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%% Book Chapters
@misc{fds192605,
Author = {L.E. Howle},
Title = {Topics in Heat Transfer},
Booktitle = {Transport Phenomena in Porous Media, Second
Edition},
Publisher = {Pergamon},
Editor = {D.B. Ingham and I. Pop},
Year = {2002},
Key = {fds192605}
}
%% Papers Published
@article{fds355638,
Author = {Wu, CY and Nowacek, DP and Nousek-McGregor, AE and McGregor, R and Howle, LE},
Title = {Computational fluid dynamics of flow regime and hydrodynamic
forces generated by a gliding North Atlantic right whale
(Eubalaena glacialis)},
Journal = {Marine Mammal Science},
Volume = {37},
Number = {3},
Pages = {826-842},
Year = {2021},
Month = {July},
url = {http://dx.doi.org/10.1111/mms.12798},
Abstract = {Accurate estimates of drag on marine animals are required to
investigate the locomotive cost, propulsive efficiency, and
the impacts of entanglement if the animal is carrying
fishing gear. In this study, we performed computational
fluid dynamics analysis of a 10 m (length over all) right
whale to obtain baseline measurements of drag on the animal.
Swimming speeds covering known right whale speed range
(0.125 m/s to 8 m/s) were tested. We found a weak dependence
between drag coefficient and Reynolds number. At a swimming
speed of 2 m/s, we analyzed the boundary layer thicknesses,
the flow regimes, and drag components. We found the thickest
boundary layer at the lateral sides of the peduncle, whereas
the boundary layer thickness over the outer part of the
flukes was less than 1.7 cm. Laminar flow occurred over the
anterior ~0.6 LoA and turbulent flow from ~0.8 LoA to the
fluke notch. On the surfaces of the flukes outside of the
body wake region, flow was laminar. Our most significant
finding is that the drag coefficient (0.0071–0.0059) of a
right whale for swimming speeds ranging from 0.25 m/s to 2
m/s is approximately twice that of many previous estimates
for cetaceans.},
Doi = {10.1111/mms.12798},
Key = {fds355638}
}
@article{fds354607,
Author = {Schwartz, FR and Lewis, DS and King, AE and Murphy, FG and Howle, LE and Kim, CY and Nelson, RC},
Title = {Hemodialysis catheter integrity during mechanical power
injection of iodinated contrast medium for computed
tomography angiography.},
Journal = {Abdom Radiol (Ny)},
Volume = {46},
Number = {6},
Pages = {2961-2967},
Year = {2021},
Month = {June},
url = {http://dx.doi.org/10.1007/s00261-020-02905-9},
Abstract = {PURPOSE: CT angiography (CTA) requires vascular access with
flow rates of 5-7 mL/s. Hemodialysis (HD) is performed at
6-10 mL/s. The purpose of our study is to evaluate the
structural integrity of HD catheters in the administration
of contrast media via a mechanical power injector under
varying conditions. METHODS: Four HD catheters were
evaluated in an in vitro study. Tested were contrast media
type (iopamidol 300 and 370 mgI/mL), temperature (25 and 37
°C), catheter diameter (14 Fr to 16 Fr all with
double-lumen capacity), catheter length (19-32 cm), and
simultaneous double-lumen or single-lumen injection within
each of the catheters. Peak plateau pressures (psi) were
recorded with flow rates from 5 to 20 mL/s in 5 mL/s
increments. In total, 864 unique injections were performed.
RESULTS: No catheter failure (bulging/rupture) was observed
in 864 injections. Maximum pressure for single-lumen
injection was 51.7 psi (double-lumen: 26.3 psi). Peak
pressures were significantly lower in simultaneous
double-lumen vs. single-lumen injections (p < 0.001) and
low vs. high viscosity contrast media (p < 0.001).
Neither larger vs. smaller diameter lumens (p = 0.221)
nor single-lumen injection in arterial vs. venous
(p = 0.834) were significantly different. CONCLUSION: HD
catheters can be used to safely administer iodinated
contrast media via mechanical power injection in in vitro
operating conditions. Maximum peak pressure is below the
manufacturer's 30 psi limit at flow rates up to 20 mL/s in
double-lumen injections and up to 10 mL/s in single-lumen
injections, which is higher than the usual maximum of
8 mL/s for CT angiography in clinical settings.},
Doi = {10.1007/s00261-020-02905-9},
Key = {fds354607}
}
@article{fds366345,
Author = {King, AE and Andriano, NR and Howle, LE},
Title = {Trinomial decompression sickness model using full, marginal,
and non-event outcomes.},
Journal = {Computers in Biology and Medicine},
Volume = {118},
Pages = {103640},
Year = {2020},
Month = {March},
url = {http://dx.doi.org/10.1016/j.compbiomed.2020.103640},
Abstract = {Decompression sickness (DCS) is a condition associated with
reductions in ambient pressure during underwater diving and
altitude exposure. Determining the risk of DCS from a dive
exposure remains an active area of research, with the goal
of developing safe decompression schedules to mitigate the
occurrence of DCS. This work develops a probabilistic model
for the trinomial outcome of full, marginal, and no DCS. The
model treats full DCS and marginal DCS as separate, fully
weighted hierarchical events. Six variants of
exponential-exponential (EE) and linear-exponential (LE)
decompression models were optimized to fit dive outcomes
from the BIG292 empirical human dive trial data of 3322
exposures. Using the log likelihood difference test, the LE1
trinomial marginal model was determined to provide the best
fit for the data. The LE1 trinomial marginal model can be
used to better understand decompression schedules, expanding
upon binomial models which treat marginal DCS as either a
fractionally weighted event or a non-event. Future work
could investigate whether the use of marginal DCS cases
improves multinomial probabilistic DCS model performance.
Model improvement could include the addition of a fourth
outcome, where full DCS is split and categorized as serious
or mild DCS, creating a tetranomial model with serious,
mild, marginal, and no DCS outcomes for comparison with the
presently developed model.},
Doi = {10.1016/j.compbiomed.2020.103640},
Key = {fds366345}
}
@article{fds350186,
Author = {King, AE and Howle, LE},
Title = {Tetranomial decompression sickness model using serious,
mild, marginal, and non-event outcomes},
Journal = {Informatics in Medicine Unlocked},
Volume = {20},
Year = {2020},
Month = {January},
url = {http://dx.doi.org/10.1016/j.imu.2020.100371},
Abstract = {Decompression sickness (DCS) is a condition resulting from
reductions in ambient pressure, causing inert gas bubbles in
tissues. This work focuses on hyperbaric exposures,
specifically DCS resulting from underwater diving. Signs and
symptoms of DCS can range from mild skin rashes and joint
pain to serious neurological and cardiological malfunction,
and even death. Marginal DCS is defined as symptoms
associated with DCS that resolve spontaneously without
recompression treatment. There are two categories of
decompression modeling used to mitigate risk of DCS:
deterministic and probabilistic; neither address DCS symptom
severity. Symptom severity is important to U.S. Navy dive
planning, as the Navy has different limits for the number
allowable cases of mild-symptom DCS and more severe-symptom
DCS for a given dive. In this work, a probabilistic model
for predicting the tetranomial outcomes of serious, mild,
marginal, and no DCS was developed, analyzed, and compared
with trinomial and trinomial marginal models from our
previous works. Six variants of exponential-exponential
(EE1) and linear-exponential (LE1) models were calibrated
with 3322 air and N2–O2 dive exposures detailed in the
BIG292 empirical human dive trial data set. Two methods of
symptom severity splitting were compared. The log likelihood
difference test indicated the LE1 model using a
previously-disclosed Type A/B splitting provided the best
fit to the empirical dive data of all tetranomial models
tested in this work. When comparing this tetranomial model
to our previous trinomial and trinomial marginal models
using the Pearson chi-squared statistic, we find that the
tetranomial and trinomial marginal models’ predictions of
marginal DCS are not aligned well with the incidence of
marginal DCS in the data. Both the trinomial marginal model
in our previous work and tetranomial model presented here
are unable to accurately replicate the occurrence of
marginal DCS events observed in the BIG292 dataset. These
marginal DCS events may hinder model fit during calibration.
We recommend the use of the trinomial model from our
previous work, which simultaneously predicts the probability
of mild, serious, and no DCS.},
Doi = {10.1016/j.imu.2020.100371},
Key = {fds350186}
}
@article{fds350257,
Author = {Di Muro and G and Murphy, FG and Vann, RD and Howle,
LE},
Title = {Are interconnected compartmental models more effective at
predicting decompression sickness risk?},
Journal = {Informatics in Medicine Unlocked},
Volume = {20},
Year = {2020},
Month = {January},
url = {http://dx.doi.org/10.1016/j.imu.2020.100334},
Abstract = {Interconnected tissue compartmental models having two,
three, or four compartments, one or more of which was
risk-bearing, have been previously investigated for
predicting the probability of decompression sickness (DCS)
in compressed gas diving. We extend this prior work under
general conditions to multiple risk-bearing compartments
while providing exact risk function integrals. Four
biophysical models based on different inter-compartmental
connections ranging from uncoupled to fully coupled with
bidirectional interaction were trained on a large data set
to reject unjustified model parameters. We also explore how
coupled models (and similar uncoupled models) perform for
the prediction of DCS in humans when extrapolated to dives
outside of the training set. The most successful model
assumes slower tissues influence faster tissues with all
compartments bearing risk and provide very good predictions
for dives with surface decompression using
oxygen.},
Doi = {10.1016/j.imu.2020.100334},
Key = {fds350257}
}
@article{fds348943,
Author = {Dunford, RG and Denoble, PD and Forbes, R and Pieper, CF and Howle, LE and Vann, RD},
Title = {A study of decompression sickness using recorded depth-time
profiles.},
Journal = {Undersea & Hyperbaric Medicine : Journal of the Undersea and
Hyperbaric Medical Society, Inc},
Volume = {47},
Number = {1},
Pages = {75-91},
Year = {2020},
url = {http://dx.doi.org/10.22462/01.03.2020.9},
Abstract = {INTRODUCTION: 122,129 dives by 10,358 recreational divers
were recorded by dive computers from 11 manufacturers in an
exploratory study of how dive profile, breathing gas (air or
nitrox [N2/O2] mixes), repetitive diving, gender, age, and
dive site conditions influenced observed decompression
sickness (DCSobs). Thirty-eight reports were judged as DCS.
Overall DCSobs was 3.1 cases/10⁴ dives. METHODS: Three
dive groups were studied: Basic (live-aboard and
shore/dayboat), Cozumel Dive Guides, and Scapa Flow wreck
divers. A probabilistic decompression model, BVM(3),
controlled dive profile variability. Chi-squared test,
t-test, logistic regression, and log-rank tests evaluated
statistical associations. RESULTS: (a) DCSobs was 0.7/10⁴
(Basic), 7.6/10⁴ (Guides), and 17.3/104 (Scapa) and
differed after control for dive variability (p ≺ 0.001).
(b) DCSobs was greater for 22%-29% nitrox (12.6/10⁴) than
for 30%-50% nitrox (2.04/10⁴) (p ≤ 0.0064) which did not
differ from air (2.97/1010⁴). (c) For daily repetitive
dives (≺12-hour surface intervals (SI)), DCS occurred only
following one or two dives (4.3/1010⁴ DCSobs; p ≺ 0.001)
where SIs were shorter than after three or more dives. (d)
For multiday repetitive dives (SIs ≺ 48 hours), DCS was
associated with high multiday repetitive dive counts only
for Guides (p = 0.0018). (e) DCSobs decreased with age at
3%/year (p ≤ 0.0144). (f) Males dived deeper (p ≺ 0.001)
but for less time than females (p ≺ 0.001). CONCLUSION:
Collecting dive profiles with dive computers and controlling
for profile variability by probabilistic modeling was
feasible, but analytical results require independent
confirmation due to limited observed DCS. Future studies
appear promising if more DCS cases are gathered,
stakeholders cooperate, and identified data collection
problems are corrected.},
Doi = {10.22462/01.03.2020.9},
Key = {fds348943}
}
@article{fds339865,
Author = {Howle, LE and Kraus, SD and Werner, TB and Nowacek,
DP},
Title = {Simulation of the entanglement of a North Atlantic right
whale (Eubalaena glacialis) with fixed fishing
gear},
Journal = {Marine Mammal Science},
Volume = {35},
Number = {3},
Pages = {760-778},
Publisher = {WILEY},
Year = {2019},
Month = {July},
url = {http://dx.doi.org/10.1111/mms.12562},
Abstract = {Population estimates of the critically endangered North
Atlantic right whale (Eubalaena glacialis) put the number of
individuals at 458 with the actual number likely being lower
due to a recent unusual mortality event. Entanglement with
fixed fishing gear is the most significant cause of
mortality of North Atlantic right whales. There remains
little documentation of how North Atlantic right whales
become enwrapped during an encounter with fixed fishing
gear. In order to gain a better understanding of how
entanglements might occur, an interactive simulator was
developed that allows the user to swim a virtual whale model
using a standard game controller through a gear field in an
attempt to re-create an entanglement. The morphologically
accurate right whale model produces realistic swimming
motions and is capable of pectoral fin motions in response
to user input. Using the simulator, gear entanglements
involving the pectoral flippers including ropes wrapping
around the body and entanglements involving the tailstock
were re-created. Entanglements involving the pectoral
flippers with body wraps were more easily generated than
entanglements involving the tailstock only. The simulator
should aid scientists, fisheries experts, fishing gear
designers, and bycatch reduction scientists in understanding
entanglement dynamics and testing potential new gear
configurations.},
Doi = {10.1111/mms.12562},
Key = {fds339865}
}
@article{fds329829,
Author = {Murphy, FG and Hada, EA and Doolette, DJ and Howle,
LE},
Title = {Probabilistic pharmacokinetic models of decompression
sickness in humans: Part 2, coupled perfusion-diffusion
models.},
Journal = {Computers in Biology and Medicine},
Volume = {92},
Pages = {90-97},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1016/j.compbiomed.2017.11.011},
Abstract = {Decompression sickness (DCS) can be experienced following a
reduction in ambient pressure; such as that associated with
diving or ascent to high altitudes. DCS is believed to
result when supersaturated inert gas dissolved in biological
tissues exits solution and forms bubbles. Models to predict
the probability of DCS are typically based on nitrogen
and/or helium gas uptake and washout in several theoretical
tissues, each represented by a single perfusion-limited
compartment. It has been previously shown that coupled
perfusion-diffusion compartments are better descriptors than
solely perfusion-based models of nitrogen and helium uptake
and elimination kinetics observed in the brain and skeletal
muscle of sheep. In this work, we examine the application of
these coupled pharmacokinetic structures with at least one
diffusion compartment to the prediction of the incidence of
decompression sickness in humans. We compare these models to
LEM-NMRI98, a well-described U.S. Navy gas content model,
consisting of three uncoupled perfusion-limited compartments
incorporating oxygen and linear-exponential kinetics.
Pharmacokinetic gas content models with a diffusion
component describe the probability of DCS in human bounce
dives made with air, single non-air bounce dives, and oxygen
decompression dives better than LEM-NMRI98. However, for the
full data set, LEM-NMRI98 remains the best descriptor of the
data.},
Doi = {10.1016/j.compbiomed.2017.11.011},
Key = {fds329829}
}
@article{fds331187,
Author = {Murphy, FG and Swingler, AJ and Gerth, WA and Howle,
LE},
Title = {Iso-risk air no decompression limits after scoring marginal
decompression sickness cases as non-events.},
Journal = {Computers in Biology and Medicine},
Volume = {92},
Pages = {110-117},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1016/j.compbiomed.2017.11.012},
Abstract = {Decompression sickness (DCS) in humans is associated with
reductions in ambient pressure that occur during diving,
aviation, or certain manned spaceflight operations. Its
signs and symptoms can include, but are not limited to,
joint pain, radiating abdominal pain, paresthesia, dyspnea,
general malaise, cognitive dysfunction, cardiopulmonary
dysfunction, and death. Probabilistic models of DCS allow
the probability of DCS incidence and time of occurrence
during or after a given hyperbaric or hypobaric exposure to
be predicted based on how the gas contents or gas bubble
volumes vary in hypothetical tissue compartments during the
exposure. These models are calibrated using data containing
the pressure and respired gas histories of actual exposures,
some of which resulted in DCS, some of which did not, and
others in which the diagnosis of DCS was not clear. The
latter are referred to as marginal DCS cases. In earlier
works, a marginal DCS event was typically weighted as 0.1,
with a full DCS event being weighted as 1.0, and a non-event
being weighted as 0.0. Recent work has shown that marginal
DCS events should be weighted as 0.0 when calibrating gas
content models. We confirm this indication in the present
work by showing that such models have improved performance
when calibrated to data with marginal DCS events coded as
non-events. Further, we investigate the ramifications of
derating marginal events on model-prescribed air diving
no-stop limits.},
Doi = {10.1016/j.compbiomed.2017.11.012},
Key = {fds331187}
}
@article{fds329575,
Author = {King, AE and Murphy, FG and Howle, LE},
Title = {Bimodal decompression sickness onset times are not related
to dive type or event severity.},
Journal = {Computers in Biology and Medicine},
Volume = {91},
Pages = {59-68},
Year = {2017},
Month = {December},
url = {http://dx.doi.org/10.1016/j.compbiomed.2017.10.010},
Abstract = {Human decompression sickness (DCS) is a condition associated
with depressurization during underwater diving. Human
research dive trial data containing dive outcome (DCS,
no-DCS) and symptom information are used to calibrate
probabilistic DCS models. DCS symptom onset time information
is visualized using occurrence density functions (ODF) which
plot the DCS onset rate per unit time. For the BIG292 human
dive trial data set, a primary U.S. Navy model calibration
set, the ODFs are bimodal, however probabilistic models do
not produce bimodal ODFs. We investigate the source of
bimodality by partitioning the BIG292 data based on dive
type, DCS event severity, DCS symptom type, institution, and
chronology of dive trial. All but one variant of data
partitioning resulted in a bimodal or ambiguously shaped
ODF, indicating that ODF bimodality is not related to the
dive type or the DCS event severity. Rather, we find that
the dive trial medical surveillance protocol used to
determine DCS symptom onset time may have biased the
reported event window. Thus, attempts to develop
probabilistic DCS models that reproduce BIG292 bimodality
are unlikely to result in an improvement in model
performance for data outside of the calibration
set.},
Doi = {10.1016/j.compbiomed.2017.10.010},
Key = {fds329575}
}
@article{fds326652,
Author = {Murphy, FG and Hada, EA and Doolette, DJ and Howle,
LE},
Title = {Probabilistic pharmacokinetic models of decompression
sickness in humans, part 1: Coupled perfusion-limited
compartments.},
Journal = {Computers in Biology and Medicine},
Volume = {86},
Pages = {55-64},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1016/j.compbiomed.2017.04.014},
Abstract = {Decompression sickness (DCS) is a disease caused by gas
bubbles forming in body tissues following a reduction in
ambient pressure, such as occurs in scuba diving.
Probabilistic models for quantifying the risk of DCS are
typically composed of a collection of independent,
perfusion-limited theoretical tissue compartments which
describe gas content or bubble volume within these
compartments. It has been previously shown that
'pharmacokinetic' gas content models, with compartments
coupled in series, show promise as predictors of the
incidence of DCS. The mechanism of coupling can be through
perfusion or diffusion. This work examines the application
of five novel pharmacokinetic structures with compartments
coupled by perfusion to the prediction of the probability
and time of onset of DCS in humans. We optimize these models
against a training set of human dive trial data consisting
of 4335 exposures with 223 DCS cases. Further, we examine
the extrapolation quality of the models on an additional set
of human dive trial data consisting of 3140 exposures with
147 DCS cases. We find that pharmacokinetic models describe
the incidence of DCS for single air bounce dives better than
a single-compartment, perfusion-limited model. We further
find the U.S. Navy LEM-NMRI98 is a better predictor of DCS
risk for the entire training set than any of our
pharmacokinetic models. However, one of the pharmacokinetic
models we consider, the CS2T3 model, is a better predictor
of DCS risk for single air bounce dives and oxygen
decompression dives. Additionally, we find that LEM-NMRI98
outperforms CS2T3 on the extrapolation data.},
Doi = {10.1016/j.compbiomed.2017.04.014},
Key = {fds326652}
}
@article{fds323591,
Author = {Howle, LE and Weber, PW and Nichols, JM},
Title = {Bayesian approach to decompression sickness model parameter
estimation.},
Journal = {Computers in Biology and Medicine},
Volume = {82},
Pages = {3-11},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.1016/j.compbiomed.2017.01.006},
Abstract = {We examine both maximum likelihood and Bayesian approaches
for estimating probabilistic decompression sickness model
parameters. Maximum likelihood estimation treats parameters
as fixed values and determines the best estimate through
repeated trials, whereas the Bayesian approach treats
parameters as random variables and determines the parameter
probability distributions. We would ultimately like to know
the probability that a parameter lies in a certain range
rather than simply make statements about the repeatability
of our estimator. Although both represent powerful methods
of inference, for models with complex or multi-peaked
likelihoods, maximum likelihood parameter estimates can
prove more difficult to interpret than the estimates of the
parameter distributions provided by the Bayesian approach.
For models of decompression sickness, we show that while
these two estimation methods are complementary, the credible
intervals generated by the Bayesian approach are more
naturally suited to quantifying uncertainty in the model
parameters.},
Doi = {10.1016/j.compbiomed.2017.01.006},
Key = {fds323591}
}
@article{fds325132,
Author = {Fiore, G and Anderson, E and Garborg, CS and Murray, M and Johnson, M and Moore, MJ and Howle, L and Shorter, KA},
Title = {From the track to the ocean: Using flow control to improve
marine bio-logging tags for cetaceans.},
Journal = {Plos One},
Volume = {12},
Number = {2},
Pages = {e0170962},
Editor = {Aegerter, CM},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1371/journal.pone.0170962},
Abstract = {Bio-logging tags are an important tool for the study of
cetaceans, but superficial tags inevitably increase
hydrodynamic loading. Substantial forces can be generated by
tags on fast-swimming animals, potentially affecting
behavior and energetics or promoting early tag removal.
Streamlined forms have been used to reduce loading, but
these designs can accelerate flow over the top of the tag.
This non-axisymmetric flow results in large lift forces
(normal to the animal) that become the dominant force
component at high speeds. In order to reduce lift and
minimize total hydrodynamic loading this work presents a new
tag design (Model A) that incorporates a hydrodynamic body,
a channel to reduce fluid speed differences above and below
the housing and wing to redirect flow to counter lift.
Additionally, three derivatives of the Model A design were
used to examine the contribution of individual flow control
features to overall performance. Hydrodynamic loadings of
four models were compared using computational fluid dynamics
(CFD). The Model A design eliminated all lift force and
generated up to ~30 N of downward force in simulated 6 m/s
aligned flow. The simulations were validated using particle
image velocimetry (PIV) to experimentally characterize the
flow around the tag design. The results of these experiments
confirm the trends predicted by the simulations and
demonstrate the potential benefit of flow control elements
for the reduction of tag induced forces on the
animal.},
Doi = {10.1371/journal.pone.0170962},
Key = {fds325132}
}
@article{fds325394,
Author = {Howle, LE and Weber, PW and Hada, EA and Vann, RD and Denoble,
PJ},
Title = {The probability and severity of decompression
sickness.},
Journal = {Plos One},
Volume = {12},
Number = {3},
Pages = {e0172665},
Year = {2017},
url = {http://dx.doi.org/10.1371/journal.pone.0172665},
Abstract = {Decompression sickness (DCS), which is caused by inert gas
bubbles in tissues, is an injury of concern for scuba
divers, compressed air workers, astronauts, and aviators.
Case reports for 3322 air and N2-O2 dives, resulting in 190
DCS events, were retrospectively analyzed and the outcomes
were scored as (1) serious neurological, (2)
cardiopulmonary, (3) mild neurological, (4) pain, (5)
lymphatic or skin, and (6) constitutional or nonspecific
manifestations. Following standard U.S. Navy medical
definitions, the data were grouped into mild-Type I
(manifestations 4-6)-and serious-Type II (manifestations
1-3). Additionally, we considered an alternative grouping of
mild-Type A (manifestations 3-6)-and serious-Type B
(manifestations 1 and 2). The current U.S. Navy guidance
allows for a 2% probability of mild DCS and a 0.1%
probability of serious DCS. We developed a hierarchical
trinomial (3-state) probabilistic DCS model that
simultaneously predicts the probability of mild and serious
DCS given a dive exposure. Both the Type I/II and Type A/B
discriminations of mild and serious DCS resulted in a highly
significant (p << 0.01) improvement in trinomial model fit
over the binomial (2-state) model. With the Type I/II
definition, we found that the predicted probability of
'mild' DCS resulted in a longer allowable bottom time for
the same 2% limit. However, for the 0.1% serious DCS limit,
we found a vastly decreased allowable bottom dive time for
all dive depths. If the Type A/B scoring was assigned to
outcome severity, the no decompression limits (NDL) for air
dives were still controlled by the acceptable serious DCS
risk limit rather than the acceptable mild DCS risk limit.
However, in this case, longer NDL limits were allowed than
with the Type I/II scoring. The trinomial model mild and
serious probabilities agree reasonably well with the current
air NDL only with the Type A/B scoring and when 0.2% risk of
serious DCS is allowed.},
Doi = {10.1371/journal.pone.0172665},
Key = {fds325394}
}
@article{fds281361,
Author = {Alex Shorter and K and Murray, MM and Johnson, M and Moore, M and Howle,
LE},
Title = {Drag of suction cup tags on swimming animals: Modeling and
measurement},
Journal = {Marine Mammal Science},
Volume = {30},
Number = {2},
Pages = {726-746},
Year = {2014},
Month = {January},
ISSN = {0824-0469},
url = {http://dx.doi.org/10.1111/mms.12083},
Abstract = {Bio-logging tags are widely used to study the behavior and
movements of marine mammals with the tacit assumption of
little impact to the animal. However, tags on fast-swimming
animals generate substantial hydrodynamic forces potentially
affecting behavior and energetics adversely, or promoting
early removal of the tag. In this work, hydrodynamic loading
of three novel tag housing designs are compared over a range
of swimming speeds using computational fluid dynamics (CFD).
Results from CFD simulation were verified using tag models
in a water flume with close agreement. Drag forces were
reduced by minimizing geometric disruptions to the flow
around the housing, while lift forces were reduced by
minimizing the frontal cross-sectional area of the housing
and holding the tag close to the attachment surface.
Hydrodynamic tag design resulted in an experimentally
measured 60% drag force reduction in 5.6 m/s flow. For all
housing designs, off-axis flow increased the magnitude of
the force on the tag. Experimental work with a common
dolphin (Delphinus delphis) cadaver indicates that the
suction cups used to attach the types of tags described here
provide sufficient attachment force to resist failure to
predicted forces at swimming speeds of up to 10 m/s. © 2013
The Authors. Marine Mammal Science published by Wiley
Periodicals, Inc. on behalf of Society for Marine
Mammalogy.},
Doi = {10.1111/mms.12083},
Key = {fds281361}
}
@article{fds281362,
Author = {Balmer, BC and Wells, RS and Howle, LE and Barleycorn, AA and McLellan,
WA and Ann Pabst and D and Rowles, TK and Schwacke, LH and Townsend, FI and Westgate, AJ and Zolman, ES},
Title = {Advances in cetacean telemetry: A review of single-pin
transmitter attachment techniques on small cetaceans and
development of a new satellite-linked transmitter
design},
Journal = {Marine Mammal Science},
Volume = {30},
Number = {2},
Pages = {656-673},
Year = {2014},
Month = {January},
ISSN = {0824-0469},
url = {http://dx.doi.org/10.1111/mms.12072},
Abstract = {Electronic tags have proven to be valuable tools in
assessing small cetacean movement and behavior. However,
problems associated with tag size and attachment have
limited duration and damaged dorsal fins. These outcomes
have motivated researchers to develop a new satellite-linked
tag design that reduces detrimental effects to tagged
animals, while increasing transmission durations. The goals
of this study were to review previous studies that deployed
single-pin transmitters and determine factors that influence
transmission duration. Then, test these factors utilizing
computational fluid dynamics (CFD) models to identify an
optimal single-pin satellite-linked tag design, and evaluate
this prototype through field studies. A review of four
projects, which deployed 77 single-pin radio tags,
determined that tags attached along the lower third of the
dorsal fin and approximately 33 mm from the trailing edge
resulted in longer transmission durations and reduced
negative impacts to the dorsal fin. Based upon these results
and CFD modeling, prototype, single-pin satellite-linked
tags (n = 25) transmitted for 163 ± 22 d (mean ± 95% CI)
which greatly exceeded transmissions for previous small
cetacean telemetry studies. These results suggest that the
newly developed single-pin satellite-linked tag design
strikes a balance between reducing impacts to the individual
while maximizing transmissions. © 2013 Society for Marine
Mammalogy.},
Doi = {10.1111/mms.12072},
Key = {fds281362}
}
@article{fds281363,
Author = {Weber, PW and Howle, LE and Murray, MM and Reidenberg, JS and Fish,
FE},
Title = {Hydrodynamic performance of the flippers of large-bodied
cetaceans in relation to locomotor ecology},
Journal = {Marine Mammal Science},
Volume = {30},
Number = {2},
Pages = {413-432},
Year = {2014},
Month = {January},
ISSN = {0824-0469},
url = {http://dx.doi.org/10.1111/mms.12040},
Abstract = {Cetaceans evolved flippers that are unique in both size and
shape probably due to selection pressures associated with
foraging and body size. Flippers function as control
surfaces for maneuverability and stability. Flippers of
cetaceans and engineered hydrofoils are similar with
streamlined cross-sections and wing-like planforms, which
affect lift, drag and hydrodynamic efficiency. Scale models
of the flippers from large-bodied (body length > 6 m)
cetaceans (fin whale, killer whale, sperm whale) were
constructed from computed tomography (CT) scans of flippers.
Flipper planforms were highly tapered for the fin whale, a
rounded, paddle-like design for the killer whale, and a
square geometry for the sperm whale. Hydrodynamic properties
of the models at varying angles of attack (-40o to 40o) were
determined in a water tunnel with a multi-axis load cell.
The flippers were found to have hydrodynamic characteristics
similar to engineered wings. Differences in flipper
morphology of large-bodied cetaceans and their hydrodynamic
performance are associated with the requirements of aquatic
locomotion involved with ecology of the whales. The flippers
of the killer whale provided the greatest maneuverability,
whereas the flippers of the fin whale had low drag for
lunging and the flippers of the sperm whale provided lift
for diving. © 2013 Society for Marine Mammalogy.},
Doi = {10.1111/mms.12040},
Key = {fds281363}
}
@article{fds281366,
Author = {Howle, LE},
Title = {Analytic gain in probabilistic decompression sickness
models.},
Journal = {Computers in Biology and Medicine},
Volume = {43},
Number = {11},
Pages = {1739-1747},
Year = {2013},
Month = {November},
ISSN = {0010-4825},
url = {http://dx.doi.org/10.1016/j.compbiomed.2013.07.026},
Abstract = {Decompression sickness (DCS) is a disease known to be
related to inert gas bubble formation originating from gases
dissolved in body tissues. Probabilistic DCS models, which
employ survival and hazard functions, are optimized by
fitting model parameters to experimental dive data. In the
work reported here, I develop methods to find the survival
function gain parameter analytically, thus removing it from
the fitting process. I show that the number of iterations
required for model optimization is significantly reduced.
The analytic gain method substantially improves the
condition number of the Hessian matrix which reduces the
model confidence intervals by more than an order of
magnitude.},
Doi = {10.1016/j.compbiomed.2013.07.026},
Key = {fds281366}
}
@article{fds281364,
Author = {Alex Shorter and K and Murray, MM and Johnson, M and Moore, M and Howle,
LE},
Title = {Drag of suction cup tags on swimming animals: Modeling and
measurement},
Journal = {Marine Mammal Science},
Year = {2013},
ISSN = {0824-0469},
Key = {fds281364}
}
@article{fds281365,
Author = {Balmer, BC and Wells, RS and Howle, LE and Barleycorn, AA and Mcclellan,
WA and Ann Pabst and D and Rowles, TK and Schwacke, LH and Townsend, FI and Westgate, AJ and Zolman, ES},
Title = {Advances in cetacean telemetry: A review of single-pin
transmitter attachment techniques on small cetaceans and
development of a new satellite-linked transmitter
design},
Journal = {Marine Mammal Science},
Year = {2013},
ISSN = {0824-0469},
Key = {fds281365}
}
@article{fds281367,
Author = {Weber, PW and Howle, LE and Murray, MM and Reidenberg, JS and Fish,
FE},
Title = {Hydrodynamic performance of the flippers of large-bodied
cetaceans in relation to locomotor ecology},
Journal = {Marine Mammal Science},
Year = {2013},
ISSN = {0824-0469},
url = {http://dx.doi.org/10.1111/mms.12040},
Abstract = {Cetaceans evolved flippers that are unique in both size and
shape probably due to selection pressures associated with
foraging and body size. Flippers function as control
surfaces for maneuverability and stability. Flippers of
cetaceans and engineered hydrofoils are similar with
streamlined cross-sections and wing-like planforms, which
affect lift, drag and hydrodynamic efficiency. Scale models
of the flippers from large-bodied (body length > 6 m)
cetaceans (fin whale, killer whale, sperm whale) were
constructed from computed tomography (CT) scans of flippers.
Flipper planforms were highly tapered for the fin whale, a
rounded, paddle-like design for the killer whale, and a
square geometry for the sperm whale. Hydrodynamic properties
of the models at varying angles of attack (-40o to 40o) were
determined in a water tunnel with a multi-axis load cell.
The flippers were found to have hydrodynamic characteristics
similar to engineered wings. Differences in flipper
morphology of large-bodied cetaceans and their hydrodynamic
performance are associated with the requirements of aquatic
locomotion involved with ecology of the whales. The flippers
of the killer whale provided the greatest maneuverability,
whereas the flippers of the fin whale had low drag for
lunging and the flippers of the sperm whale provided lift
for diving. © 2013 Society for Marine Mammalogy.},
Doi = {10.1111/mms.12040},
Key = {fds281367}
}
@article{fds281376,
Author = {Bashir, MR and Weber, PW and Husarik, DB and Howle, LE and Nelson,
RC},
Title = {Improved aortic enhancement in CT angiography using
slope-based triggering with table speed optimization: a
pilot study.},
Journal = {Int J Cardiovasc Imaging},
Volume = {28},
Number = {6},
Pages = {1533-1543},
Year = {2012},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21898186},
Abstract = {To assess whether a scan triggering technique based on the
slope of the time-attenuation curve combined with table
speed optimization may improve arterial enhancement in
aortic CT angiography compared to conventional
threshold-based triggering techniques. Measurements of
arterial enhancement were performed in a physiologic flow
phantom over a range of simulated cardiac outputs (2.2-8.1
L/min) using contrast media boluses of 80 and 150 mL
injected at 4 mL/s. These measurements were used to
construct computer models of aortic attenuation in CT
angiography, using cardiac output, aortic diameter, and CT
table speed as input parameters. In-plane enhancement was
calculated for normal and aneurysmal aortic diameters.
Calculated arterial enhancement was poor (<150 HU) along
most of the scan length using the threshold-based triggering
technique for low cardiac outputs and the aneurysmal aorta
model. Implementation of the slope-based triggering
technique with table speed optimization improved enhancement
in all scenarios and yielded good- (>200 HU; 13/16
scenarios) to excellent-quality (>300 HU; 3/16 scenarios)
enhancement in all cases. Slope-based triggering with table
speed optimization may improve the technical quality of
aortic CT angiography over conventional threshold-based
techniques, and may reduce technical failures related to low
cardiac output and slow flow through an aneurysmal
aorta.},
Doi = {10.1007/s10554-011-9945-8},
Key = {fds281376}
}
@article{fds281375,
Author = {Husarik, DB and Bashir, MR and Weber, PW and Nichols, EB and Howle, LE and Merkle, EM and Nelson, RC},
Title = {Contrast-enhanced magnetic resonance angiography: first-pass
arterial enhancement as a function of gadolinium-chelate
concentration, and the saline chaser volume and injection
rate.},
Journal = {Investigative Radiology},
Volume = {47},
Number = {2},
Pages = {121-127},
Year = {2012},
Month = {February},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21934516},
Abstract = {OBJECTIVE: To evaluate the effect of the contrast medium
(CM) concentration and the saline chaser volume and
injection rate on first-pass aortic enhancement
characteristics in contrast-enhanced magnetic resonance
angiography using a physiologic flow phantom. MATERIALS AND
METHODS: Imaging was performed on a 3.0-T magnetic resonance
system (MAGNETOM Trio, Siemens Healthcare Solutions, Inc,
Erlangen, Germany) using a 2-dimensional fast low angle shot
T1-weighted sequence (repetition time, 500 milliseconds;
echo time, 1.23 milliseconds; flip angle, 8 degrees; 1
frame/s × 60 seconds). The following CM concentrations
injected at 2 mL/s were used with 3 different contrast
agents (gadolinium [Gd]-BOPTA, Gd-HP-DO3A, Gd-DTPA): 20 mL
of undiluted CM (100%) and 80%, 40%, 20%, 10%, 5%, and 2.5%
of the full amount, all diluted in saline to a volume of 20
mL to ensure equal bolus volume. The CM was followed by
saline chasers of 20 to 60 mL injected at 2 mL/s and 6 mL/s.
Aortic signal intensity (SI) was measured, and normalized SI
versus time (SI/Tn) curves were generated. The maximal SI
(SI(max)), bolus length, and areas under the SI/Tn curve
were calculated. RESULTS: Decreasing the CM concentration
from 100% to 40% resulted in a decrease of SI(max) to 86.1%
(mean). Further decreasing the CM concentration to 2.5%
decreased SI(max) to 5.1% (mean). Altering the saline chaser
volume had no significant effect on SI(max). Increasing the
saline chaser injection rate had little effect (mean
increase, 2.2%) on SI(max) when using ≥40% of CM. There
was a larger effect (mean increase, 19.6%) when ≤20% of CM
were used. Bolus time length was significantly shorter (P <
0.001), and area under the SI/T(n) curve was significantly
smaller (P < 0.01) for the CM protocols followed by a saline
chaser injected at 6 mL/s compared with a saline chaser
injected at 2 mL/s. CONCLUSION: With 40% of CM and a fast
saline chaser, SImax close to that with undiluted CM can be
achieved. An increased saline chaser injection rate has a
more pronounced effect on aortic enhancement characteristics
at lower CM concentrations than at higher CM
concentrations.},
Doi = {10.1097/RLI.0b013e3182300603},
Key = {fds281375}
}
@article{fds281370,
Author = {Fish, FE and Weber, PW and Murray, MM and Howle, LE},
Title = {Marine applications of the biomimetic humpback whale
flipper},
Journal = {Marine Technology Society Journal},
Volume = {45},
Number = {4},
Pages = {198-207},
Publisher = {Marine Technology Society},
Year = {2011},
Month = {July},
ISSN = {0025-3324},
url = {http://dx.doi.org/10.4031/MTSJ.45.4.1},
Abstract = {The biomimetic approach seeks technological advancement
through a transfer of technology from natural technologies
to engineered systems. The morphology of the wing-like
flipper of the humpback whale has potential for marine
applications. As opposed to the straight leading edge of
conventional hydrofoils, the humpback whale flipper has a
number of sinusoid-like rounded bumps, called tubercles,
which are arranged periodically along the leading edge. The
presence of the tubercles modifies the water flow over the
wing-like surface, creating regions of vortex generation
between the tubercles. These vortices interact with the flow
over the tubercle and accelerate that flow, helping to
maintain a partially attached boundary layer. This
hydrodynamic effect can delay stall to higher angles of
attack, increases lift, and reduces drag compared to the
post-stall condition of conventional wings. As the humpback
whale functions in the marine environment in a Reynolds
regime similar to some engineered marine systems, the use of
tubercles has the potential to enhance the performance of
wing-like structures. Specific applications of the tubercles
for marine technology include sailboat masts, fans,
propellers, turbines, and control surfaces, such as rudders,
dive planes, stabilizers, spoilers, and keels.},
Doi = {10.4031/MTSJ.45.4.1},
Key = {fds281370}
}
@article{fds281381,
Author = {Fish, FE and Weber, PW and Murray, MM and Howle, LE},
Title = {The tubercles on humpback whales' flippers: application of
bio-inspired technology.},
Journal = {Integrative and Comparative Biology},
Volume = {51},
Number = {1},
Pages = {203-213},
Year = {2011},
Month = {July},
ISSN = {1540-7063},
url = {http://dx.doi.org/10.1093/icb/icr016},
Abstract = {The humpback whale (Megaptera novaeangliae) is exceptional
among the large baleen whales in its ability to undertake
aquabatic maneuvers to catch prey. Humpback whales utilize
extremely mobile, wing-like flippers for banking and
turning. Large rounded tubercles along the leading edge of
the flipper are morphological structures that are unique in
nature. The tubercles on the leading edge act as
passive-flow control devices that improve performance and
maneuverability of the flipper. Experimental analysis of
finite wing models has demonstrated that the presence of
tubercles produces a delay in the angle of attack until
stall, thereby increasing maximum lift and decreasing drag.
Possible fluid-dynamic mechanisms for improved performance
include delay of stall through generation of a vortex and
modification of the boundary layer, and increase in
effective span by reduction of both spanwise flow and
strength of the tip vortex. The tubercles provide a
bio-inspired design that has commercial viability for
wing-like structures. Control of passive flow has the
advantages of eliminating complex, costly, high-maintenance,
and heavy control mechanisms, while improving performance
for lifting bodies in air and water. The tubercles on the
leading edge can be applied to the design of watercraft,
aircraft, ventilation fans, and windmills.},
Doi = {10.1093/icb/icr016},
Key = {fds281381}
}
@article{Weber2011b,
Author = {Weber, PW and Howle, LE and Murray, MM and Corless,
JM},
Title = {A simplified mass-transfer model for visual pigments in
amphibian retinal-cone outer segments.},
Journal = {Biophysical Journal},
Volume = {100},
Number = {3},
Pages = {525-534},
Year = {2011},
Month = {February},
ISSN = {0006-3495},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21281566},
Abstract = {When radiolabeled precursors and autoradiography are used to
investigate turnover of protein components in photoreceptive
cone outer segments (COSs), the labeled components--primarily
visual pigment molecules (opsins)--are diffusely distributed
along the COS. To further assess this COS labeling pattern,
we derive a simplified mass-transfer model for quantifying
the contributions of advective and diffusive mechanisms to
the distribution of opsins within COSs of the frog retina.
Two opsin-containing regions of the COS are evaluated: the
core axial array of disks and the plasmalemma. Numerical
solutions of the mass-transfer model indicate three distinct
stages of system evolution. In the first stage, plasmalemma
diffusion is dominant. In the second stage, the plasmalemma
density reaches a metastable state and transfer between the
plasmalemma and disk region occurs, which is followed by an
increase in density that is qualitatively similar for both
regions. The final stage consists of both regions slowly
evolving to the steady-state solution. Our results indicate
that autoradiographic and cognate approaches for tracking
labeled opsins in the COS cannot be effective methodologies
for assessing new disk formation at the base of the
COS.},
Doi = {10.1016/j.bpj.2010.11.085},
Key = {Weber2011b}
}
@article{Weber2011a,
Author = {Weber, PW and Howle, LE and Murray, MM and Miklosovic,
DS},
Title = {Computational evaluation of the performance of lifting
surfaces with leading-edge protuberances},
Journal = {Journal of Aircraft},
Volume = {48},
Number = {2},
Pages = {591-600},
Publisher = {American Institute of Aeronautics and Astronautics
(AIAA)},
Year = {2011},
Month = {January},
ISSN = {0021-8669},
url = {http://dx.doi.org/10.2514/1.C031163},
Abstract = {The leading-edge tubercles of humpback whale flippers have
been shown to enhance hydrodynamic performance by increasing
lift and decreasing drag poststall. To explore this effect,
computational simulations of two models based on an
idealized humpback whale flipper were conducted, one with a
smooth leading edge and one with simulatedleading-edge
tubercles. Two different commercial computational fluid
dynamics packages were used, STAR-CCM+ and SolidWorks Flow
Simulation, and the results were compared with experiment.
Numeric lift predictions in the nonstall region were
reasonably accurate (maximum error 6.6% between both codes),
while lift predictions in the poststall region were
problematic. Numeric drag predictions in the early nonstall
region were within experimental error for STAR-CCM+ using
the Spalart-Allmaras turbulence model, while both codes
exhibited drag prediction error in the stall region. Flow
visualizations showed that the smooth flipper exhibited
trailing-edge stall, while the simulated tubercle flipper
stalled in the troughs, behind the leading notches, first.
At high angles of attack, the simulated tubercle flipper
still possessed significant regions of attached flow, which
contributes to its ability to maintain increased lift
poststall. © Copyright 2010.},
Doi = {10.2514/1.C031163},
Key = {Weber2011a}
}
@article{fds281377,
Author = {Fish, FE and Weber, PW and Howle, LE and Murray, MM and Reidenberg,
JS},
Title = {Hydrodynamic performance of the flippers of large-bodied
cetaceans},
Journal = {Secondary Adaptation of Tetrapods to Life in
Water},
Year = {2011},
Key = {fds281377}
}
@article{fds281371,
Author = {Macha, DB and Nelson, RC and Howle, LE and Hollingsworth, JW and Schindera, ST},
Title = {Response},
Journal = {Radiology},
Volume = {255},
Number = {2},
Pages = {662},
Year = {2010},
Month = {May},
ISSN = {0033-8419},
url = {http://dx.doi.org/10.1148/radiol.092152},
Doi = {10.1148/radiol.092152},
Key = {fds281371}
}
@article{Weber2010,
Author = {Weber, PW and Howle, LE and Murray, MM},
Title = {Lift, drag, and cavitation onset on rudders with
leading-edge tubercles},
Journal = {Marine Technology},
Volume = {47},
Number = {1},
Pages = {27-36},
Year = {2010},
Month = {January},
ISSN = {0025-3316},
Abstract = {This paper presents the experimental measurement of lift and
drag as well as the determination of the onset of cavitation
on rudders with leading-edge protuberances (tubercles) that
are operating at low to moderate Reynolds Numbers in water.
The leading-edge shape used for the rudders in this study is
derived from our earlier work concerning the analysis of the
leading-edge morphology found on the pectoral flippers of
humpback whales. While humpback whales do not swim at speeds
that induce cavitation, engineered control surfaces based on
this bio-inspired control surface modification might operate
in cavitation conditions. This point motivates our present
work to investigate the onset of cavitation on small aspect
ratio rudders with tubercles. Our findings are that (i) the
presence of leading-edge tubercles accelerates the onset of
cavitation, (ii) the tubercles can modify the location of
the onset of cavitation, (iii) the tubercle geometry has an
influence on the rudder's hydrodynamic performance, (iv) for
the lower Reynolds Numbers considered in this paper, the
tubercles decrease lift and increase drag for angles of
attack between 15 and 22 deg, (v) for angles above 22 deg,
rudders with tubercles generate more lift than smooth
rudders, and (vi) for the higher Reynolds Numbers
investigated, the difference in performance between the
smooth and tubercled rudders diminishes, suggesting the
existence of a critical Reynolds Number for a given tubercle
geometry beyond which tubercles have no significant effect
on hydrodynamic performance. © Marine Technology.},
Key = {Weber2010}
}
@article{fds192649,
Author = {Husarik, D.B.B. and Mashir, M.S.R. and Weber, P.W. and Nichols, E.B. and Merkle, E.M. and Howle, L.E. and Nelson, R.C.},
Title = {Gadolinium-enhanced MR angiography: Effects of the contrast
media dose on peak signal intensity relative to the
injection rate of saline chaser},
Journal = {97th Scientific Assembly and Annual Meeting of the
Radiological Society of North America},
Year = {2010},
Key = {fds192649}
}
@article{fds192650,
Author = {Husarik, D.B.B. and Bashir, M.S.R. and Weber, P.W. and Nichols, E.B. and Howle, L.E. and Nelson, R.C.},
Title = {Gadolinium-enhanced MR Angiography: Effects of volume and
rate of the saline chaser on peak aortic signal
intensity},
Journal = {97th Scientific Assembly and Annual Meeting of the
Radiological Society of North America},
Year = {2010},
Key = {fds192650}
}
@article{fds192651,
Author = {Walker, J.R. and Hobbs, G.W. and Gault, K.A. and Howle, L.W. and Freiberger, J.J.},
Title = {The oxygen window's effect on decompression risk: 20fsw vs.
10fsw},
Journal = {Proceedings of the 2010 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2010},
Key = {fds192651}
}
@article{fds192652,
Author = {Walker, J.R. and Hobbs, G.W. and Gault, K.A. and Howle, L.W. and Freiberger, J.J.},
Title = {Decompression risk analysis comparing oxygen and 50% nitrox
decompression stops},
Journal = {Proceedings of the 2010 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2010},
Key = {fds192652}
}
@article{fds192653,
Author = {Vann, R.D. and Weber, P.W. and Di Muro and G., Howle and L.E.},
Title = {Adding venous gas emboli (VGE) to the linear-exponential
(LE) decompression model},
Journal = {Proceedings of the 2010 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2010},
Key = {fds192653}
}
@article{fds192654,
Author = {Husarik, D.B. and Weber, P.W. and Bashir, M.S.R. and Nichols, E.B. and Merkle, E.M. and Howle, L.E. and Nelson, R.C.},
Title = {Gadolinium-enhanced MR angiography: Optimization of contrast
media doses for imaging patients with compromised renal
function},
Journal = {Society of Computed Body Tomography and Magnetic Resonance
Meeting},
Year = {2010},
Key = {fds192654}
}
@article{Weber2009a,
Author = {Weber, PW and Murray, MM and Howle, LE and Fish, FE},
Title = {Comparison of real and idealized cetacean
flippers.},
Journal = {Bioinspiration & Biomimetics},
Volume = {4},
Number = {4},
Pages = {046001},
Year = {2009},
Month = {December},
ISSN = {1748-3182},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19834251},
Abstract = {When a phenomenon in nature is mimicked for practical
applications, it is often done so in an idealized fashion,
such as representing the shape found in nature with
convenient, piece-wise smooth mathematical functions. The
aim of idealization is to capture the advantageous features
of the natural phenomenon without having to exactly
replicate it, and it is often assumed that the idealization
process does in fact capture the relevant geometry. We
explored the consequences of the idealization process by
creating exact scale models of cetacean flippers using CT
scans, creating corresponding idealized versions and then
determining the hydrodynamic characteristics of the models
via water tunnel testing. We found that the majority of the
idealized models did not exhibit fluid dynamic properties
that were drastically different from those of the real
models, although multiple consequences resulting from the
idealization process were evident. Drag performance was
significantly improved by idealization. Overall,
idealization is an excellent way to capture the relevant
effects of a phenomenon found in nature, which spares the
researcher from having to painstakingly create exact models,
although we have found that there are situations where
idealization may have unintended consequences such as one
model that exhibited a decrease in lift performance.},
Doi = {10.1088/1748-3182/4/4/046001},
Key = {Weber2009a}
}
@article{Coursey2009,
Author = {Coursey, CA and Nelson, RC and Weber, PW and Howle, LE and Nichols, EB and Marin, D and DeLong, D},
Title = {Contrast material administration protocols for 64-MDCT
angiography: altering volume and rate and use of a saline
chaser to better match the imaging window--physiologic
phantom study.},
Journal = {Ajr. American Journal of Roentgenology},
Volume = {193},
Number = {6},
Pages = {1568-1575},
Year = {2009},
Month = {December},
ISSN = {0361-803X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19933649},
Abstract = {OBJECTIVE: The purpose of our study was to evaluate the
effect of varying volumes and rates of contrast material,
use of a saline chaser, and cardiac output on aortic
enhancement characteristics in MDCT angiography (MDCTA)
using a physiologic phantom. MATERIALS AND METHODS: Volumes
of 75, 100, and 125 mL of iopamidol, 370 mg I/mL, were
administered at rates of 4, 6, and 8 mL/s. The effect of a
saline chaser (50 mL of normal saline, 8 mL/s) was evaluated
for each volume and rate combination. Normal, reduced (33%
and 50%), and increased (25%) cardiac outputs were
simulated. Peak aortic enhancement and duration of peak
aortic enhancement were recorded. Analysis of variance
models were run with these effects, and the estimated mean
levels for the sets of factor combinations were determined.
RESULTS: Lowering the volume of contrast material resulted
in reduced peak enhancement (example, -56.2 HU [p < 0.0001]
with 75 vs 125 mL) and reduced duration of 75% peak
enhancement (example, -9.0 seconds [p < 0.0001] with 75 vs
125 mL). Increasing the rate resulted in increased peak
enhancement (example, 104.5 HU [p < 0.0001] with a rate of 8
vs 4 mL/s) and decreased duration of 75% peak enhancement
(example, -13.0 seconds [p < 0.001]). Use of a saline chaser
resulted in increased peak enhancement, and this increase
was inversely proportional to contrast material volume. Peak
enhancement increased when reduced cardiac output was
simulated. Peak enhancement decreased when increased cardiac
output was simulated. CONCLUSION: Reducing contrast material
volume from 125 to 75 mL, increasing the rate to 6 or 8
mL/s, and use of a saline chaser result in an aortic
enhancement profile that better matches the approximately
5-second imaging window possible with 64-MDCTA of the
abdomen and pelvis. Even smaller volumes of contrast
material may be adequate in patients with reduced cardiac
output.},
Doi = {10.2214/AJR.09.2670},
Key = {Coursey2009}
}
@article{Howle2009a,
Author = {Howle, LE and Weber, PW and Vann, RD},
Title = {A computationally advantageous system for fitting
probabilistic decompression models to empirical
data.},
Journal = {Computers in Biology and Medicine},
Volume = {39},
Number = {12},
Pages = {1117-1129},
Year = {2009},
Month = {December},
ISSN = {0010-4825},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19853847},
Abstract = {To investigate the nature and mechanisms of decompression
sickness (DCS), we developed a system for evaluating the
success of decompression models in predicting DCS
probability from empirical data. Model parameters were
estimated using maximum likelihood techniques. Exact
integrals of risk functions and tissue kinetics transition
times were derived. Agreement with previously published
results was excellent including: (a) maximum likelihood
values within one log-likelihood unit of previous results
and improvements by re-optimization; (b) mean predicted DCS
incidents within 1.4% of observed DCS; and (c) time of DCS
occurrence prediction. Alternative optimization and
homogeneous parallel processing techniques yielded faster
model optimization times.},
Doi = {10.1016/j.compbiomed.2009.09.006},
Key = {Howle2009a}
}
@article{Macha2009,
Author = {Macha, DB and Nelson, RC and Howle, LE and Hollingsworth, JW and Schindera, ST},
Title = {Central venous catheter integrity during mechanical power
injection of iodinated contrast medium.},
Journal = {Radiology},
Volume = {253},
Number = {3},
Pages = {870-878},
Year = {2009},
Month = {December},
ISSN = {0033-8419},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19789224},
Abstract = {PURPOSE: To evaluate a widely used nontunneled triple-lumen
central venous catheter in order to determine whether the
largest of the three lumina (16 gauge) can tolerate high
flow rates, such as those required for computed tomographic
angiography. MATERIALS AND METHODS: Forty-two catheters were
tested in vitro, including 10 new and 32 used catheters
(median indwelling time, 5 days). Injection pressures were
continuously monitored at the site of the 16-gauge central
venous catheter hub. Catheters were injected with 300 and
370 mg of iodine per milliliter of iopamidol by using a
mechanical injector at increasing flow rates until the
catheter failed. The infusion rate, hub pressure, and
location were documented for each failure event. The
catheter pressures generated during hand injection by five
operators were also analyzed. Mean flow rates and pressures
at failure were compared by means of two-tailed Student t
test, with differences considered significant at P < .05.
RESULTS: Injections of iopamidol with 370 mg of iodine per
milliliter generate more pressure than injections of
iopamidol with 300 mg of iodine per milliliter at the same
injection rate. All catheters failed in the tubing external
to the patient. The lowest flow rate at which catheter
failure occurred was 9 mL/sec. The lowest hub pressure at
failure was 262 pounds per square inch gauge (psig) for new
and 213 psig for used catheters. Hand injection of iopamidol
with 300 mg of iodine per milliliter generated peak hub
pressures ranging from 35 to 72 psig, corresponding to flow
rates ranging from 2.5 to 5.0 mL/sec. CONCLUSION: Indwelling
use has an effect on catheter material property, but even
for used catheters there is a substantial safety margin for
power injection with the particular triple-lumen central
venous catheter tested in this study, as the manufacturer's
recommendation for maximum pressure is 15
psig.},
Doi = {10.1148/radiol.2533081086},
Key = {Macha2009}
}
@article{Howle2009b,
Author = {Howle, LE and Weber, PW and Vann, RD and Campbell,
MC},
Title = {Marginal DCS events: their relation to decompression and use
in DCS models.},
Journal = {Journal of Applied Physiology (Bethesda, Md. :
1985)},
Volume = {107},
Number = {5},
Pages = {1539-1547},
Year = {2009},
Month = {November},
ISSN = {8750-7587},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19696367},
Abstract = {We consider the nature and utility of marginal decompression
sickness (DCS) events in fitting probabilistic decompression
models to experimental dive trial data. Previous works have
assigned various fractional weights to marginal DCS events,
so that they contributed to probabilistic model parameter
optimization, but less so than did full DCS events.
Inclusion of fractional weight for marginal DCS events
resulted in more conservative model predictions. We explore
whether marginal DCS events are correlated with exposure to
decompression or are randomly occurring events. Three null
models are developed and compared with a known decompression
model that is tuned on dive trial data containing only
marginal DCS and non-DCS events. We further investigate the
technique by which marginal DCS events were previously
included in parameter optimization, explore the effects of
fractional weighting of marginal DCS events on model
optimization, and explore the rigor of combining data
containing full and marginal DCS events for probabilistic
DCS model optimization. We find that although marginal DCS
events are related to exposure to decompression, empirical
dive data containing marginal and full DCS events cannot be
combined under a single DCS model. Furthermore, we find
analytically that the optimal weight for a marginal DCS
event is 0. Thus marginal DCS should be counted as no-DCS
events when probabilistic DCS models are optimized with
binomial likelihood functions. Specifically, our study finds
that inclusion of marginal DCS events in model optimization
to make the dive profiles more conservative is
counterproductive and worsens the model's fit to the full
DCS data.},
Doi = {10.1152/japplphysiol.00185.2009},
Key = {Howle2009b}
}
@article{Weber2009b,
Author = {Weber, PW and Coursey, CA and Howle, LE and Nelson, RC and Nichols, EB and Schindera, ST},
Title = {Modifying peripheral IV catheters with side holes and side
slits results in favorable changes in fluid dynamic
properties during the injection of iodinated contrast
material.},
Journal = {Ajr. American Journal of Roentgenology},
Volume = {193},
Number = {4},
Pages = {970-977},
Year = {2009},
Month = {October},
ISSN = {0361-803X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19770318},
Abstract = {OBJECTIVE: The purpose of this study was to compare a
standard peripheral end-hole angiocatheter with those
modified with side holes or side slits using experimental
optical techniques to qualitatively compare the contrast
material exit jets and using numeric techniques to provide
flow visualization and quantitative comparisons. MATERIALS
AND METHODS: A Schlieren imaging system was used to
visualize the angiocatheter exit jet fluid dynamics at two
different flow rates. Catheters were modified by drilling
through-and-through side holes or by cutting slits into the
catheters. A commercial computational fluid dynamics package
was used to calculate numeric results for various vessel
diameters and catheter orientations. RESULTS: Experimental
images showed that modifying standard peripheral IV
angiocatheters with side holes or side slits qualitatively
changed the overall flow field and caused the exiting jet to
become less well defined. Numeric calculations showed that
the addition of side holes or slits resulted in a 9-30%
reduction of the velocity of contrast material exiting the
end hole of the angiocatheter. With the catheter tip
directed obliquely to the wall, the maximum wall shear
stress was always highest for the unmodified catheter and
was always lowest for the four-side-slit catheter.
CONCLUSION: Modified angiocatheters may have the potential
to reduce extravasation events in patients by reducing
vessel wall shear stress.},
Doi = {10.2214/AJR.09.2521},
Key = {Weber2009b}
}
@article{Weber2009c,
Author = {Weber, Paul W. and Howle, Laurens E. and Murray, Mark M. and Fish, Frank E.},
Title = {Lift and drag performance of odontocete cetacean
flippers},
Journal = {JOURNAL OF EXPERIMENTAL BIOLOGY},
Volume = {212},
Number = {14},
Pages = {2149--2158},
Year = {2009},
Month = {July},
ISSN = {0022-0949},
url = {http://dx.doi.org/10.1242/jeb.029868},
Abstract = {Cetaceans (whales, dolphins and porpoises) have evolved
flippers that aid in effective locomotion through their
aquatic environments. Differing evolutionary pressures upon
cetaceans, including hunting and feeding requirements, and
other factors such as animal mass and size have resulted in
flippers that are unique among each species. Cetacean
flippers may be viewed as being analogous to modern
engineered hydrofoils, which have hydrodynamic properties
such as lift coefficient, drag coefficient and associated
efficiency. Field observations and the collection of
biological samples have resulted in flipper geometry being
known for most cetacean species. However, the hydrodynamic
properties of cetacean flippers have not been rigorously
examined and thus their performance properties are unknown.
By conducting water tunnel testing using scale models of
cetacean flippers derived via computed tomography (CT)
scans, as well as computational fluid dynamic (CFD)
simulations, we present a baseline work to describe the
hydrodynamic properties of several cetacean flippers. We
found that flippers of similar planform shape had similar
hydrodynamic performance properties. Furthermore, one group
of flippers of planform shape similar to modern swept wings
was found to have lift coefficients that increased with
angle of attack nonlinearly, which was caused by the onset
of vortex-dominated lift. Drag coefficient versus angle of
attack curves were found to be less dependent on planform
shape. Our work represents a step towards the understanding
of the association between performance, ecology, morphology
and fluid mechanics based on the three-dimensional geometry
of cetacean flippers.},
Doi = {10.1242/jeb.029868},
Key = {Weber2009c}
}
@booklet{Weber09,
Author = {Weber, PW and Howle, LE and Murray, MM and Fish, FE},
Title = {Lift and drag performance of odontocete cetacean
flippers.},
Journal = {The Journal of Experimental Biology},
Volume = {212},
Number = {Pt 14},
Pages = {2149-2158},
Year = {2009},
Month = {July},
ISSN = {0022-0949},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000268136600007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Cetaceans (whales, dolphins and porpoises) have evolved
flippers that aid in effective locomotion through their
aquatic environments. Differing evolutionary pressures upon
cetaceans, including hunting and feeding requirements, and
other factors such as animal mass and size have resulted in
flippers that are unique among each species. Cetacean
flippers may be viewed as being analogous to modern
engineered hydrofoils, which have hydrodynamic properties
such as lift coefficient, drag coefficient and associated
efficiency. Field observations and the collection of
biological samples have resulted in flipper geometry being
known for most cetacean species. However, the hydrodynamic
properties of cetacean flippers have not been rigorously
examined and thus their performance properties are unknown.
By conducting water tunnel testing using scale models of
cetacean flippers derived via computed tomography (CT)
scans, as well as computational fluid dynamic (CFD)
simulations, we present a baseline work to describe the
hydrodynamic properties of several cetacean flippers. We
found that flippers of similar planform shape had similar
hydrodynamic performance properties. Furthermore, one group
of flippers of planform shape similar to modern swept wings
was found to have lift coefficients that increased with
angle of attack nonlinearly, which was caused by the onset
of vortex-dominated lift. Drag coefficient versus angle of
attack curves were found to be less dependent on planform
shape. Our work represents a step towards the understanding
of the association between performance, ecology, morphology
and fluid mechanics based on the three-dimensional geometry
of cetacean flippers.},
Doi = {10.1242/jeb.029868},
Key = {Weber09}
}
@article{Vann2009,
Author = {Vann, RD and Denoble, PJ and Howle, LE and Weber, PW and Freiberger, JJ and Pieper, CF},
Title = {Resolution and severity in decompression
illness.},
Journal = {Aviation, Space, and Environmental Medicine},
Volume = {80},
Number = {5},
Pages = {466-471},
Year = {2009},
Month = {May},
ISSN = {0095-6562},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19456008},
Abstract = {omegaWe review the terminology of decompression illness
(DCI), investigations of residual symptoms of decompression
sickness (DCS), and application of survival analysis for
investigating DCI severity and resolution. The Type 1 and
Type 2 DCS classifications were introduced in 1960 for
compressed air workers and adapted for diving and altitude
exposure with modifications based on clinical judgment
concerning severity and therapy. In practice, these proved
ambiguous, leading to recommendations that manifestations,
not cases, be classified. A subsequent approach assigned
individual scores to manifestations and correlated total
case scores with the presence of residual symptoms after
therapy. The next step used logistic regression to find the
statistical association of manifestations to residual
symptoms at a single point in time. Survival analysis, a
common statistical method in clinical trials and
longitudinal epidemiological studies, is a logical extension
of logistic regression. The method applies to a continuum of
resolution times, allows for time varying information, can
manage cases lost to follow-up (censored), and has potential
for investigating questions such as optimal therapy and DCI
severity. There are operational implications as well.
Appropriate definitions of mild and serious manifestations
are essential for computing probabilistic decompression
procedures where severity determines the DCS probability
that is acceptable. Application of survival analysis to DCI
data would require more specific case information than is
commonly recorded.},
Doi = {10.3357/asem.2471.2009},
Key = {Vann2009}
}
@article{Fish2009,
Author = {Fish, FE and Timm, LL and Murray, MM and Howle, LE},
Title = {Ecological morphology of the flippers of cetaceans based on
two-dimensional geometry},
Journal = {Integrative and Comparative Biology},
Volume = {49},
Pages = {E229-E229},
Publisher = {OXFORD UNIV PRESS INC},
Year = {2009},
Month = {February},
ISSN = {1540-7063},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000268808800911&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Key = {Fish2009}
}
@article{fds192655,
Author = {Murray, M. and Weber, P. and Howle, E. and Fish, F.},
Title = {Comparison of real and idealized cetacean
flippers},
Journal = {American Physical Society Division of Fluid Dynamics
Meeting},
Year = {2009},
Key = {fds192655}
}
@article{fds192656,
Author = {Howle, L.E. and Weber, P.W. and Vann, R.D. and Denoble, P.J. and Campbell, M.C.},
Title = {Probabilistic DCS models using hierarchical outcome
severity},
Journal = {Proceedings of the 2009 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2009},
Key = {fds192656}
}
@article{fds192657,
Author = {Howle, L.E. and Weber, P.W. and Vann, R.D. and Denoble, P.J. and Campbell, M.C.},
Title = {The role of marginal outcomes in the fitting of
probabilistic DCS models},
Journal = {Proceedings of the 2009 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2009},
Key = {fds192657}
}
@article{fds192658,
Author = {Vann, R.D. and Denoble, P.J. and Howle, L.E. and Weber, P.W. and Freiberger, J.J. and Pieper, C.F. and Nord, D.},
Title = {Decompression illness (DCI) and survival
analysis},
Journal = {Proceedings of the 2009 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2009},
Key = {fds192658}
}
@article{Fish2008,
Author = {Fish, Frank E. and Howle, Laurens E. and Murray, Mark
M.},
Title = {Hydrodynamic flow control in marine mammals},
Journal = {INTEGRATIVE AND COMPARATIVE BIOLOGY},
Volume = {48},
Number = {6},
Pages = {788--800},
Year = {2008},
Month = {December},
ISSN = {1540-7063},
url = {http://dx.doi.org/10.1093/icb/icn029},
Abstract = {Synopsis The ability to control the flow of water around the
body dictates the performance of marine mammals ill the
aquatic environment. Morphological specializations of marine
mammals afford mechanisms for passive flow control. Aside
from the design of the body, which minimizes drag, the
morphology of the appendages provides hydrodynamic
advantages with respect to drag, lift, thrust, and stall.
The flukes of cetaceans and sirenians and flippers of
pinnipeds possess geometries with flexibility, which enhance
thrust production for high efficiency swimming. The pectoral
flippers provide hydrodynamic lift for maneuvering. The
design of the flippers is constrained by performance
associated with stall. Delay of stall call be accomplished
passively by modification of the flipper leading edge. Such
a design is exhibited by the leading edge tubercles oil the
flippers of humpback whales (Megaptera novaeangliae). These
novel morphological structures induce a spanwise flow field
of separated vortices alternating with regions of
accelerated flow. The coupled flow regions maintain areas of
attached flow and delay stall to high angles of attack. The
delay of stall permits enhanced turning performance with
respect to both agility and maneuverability. The
morphological features of marine mammals for flow control
call be utilized in the biomimetic design of engineered
structures for increased power production and increased
efficiency.},
Doi = {10.1093/icb/icn029},
Key = {Fish2008}
}
@booklet{Fish08,
Author = {Fish, FE and Howle, LE and Murray, MM},
Title = {Hydrodynamic flow control in marine mammals.},
Journal = {Integrative and Comparative Biology},
Volume = {48},
Number = {6},
Pages = {788-800},
Year = {2008},
Month = {December},
ISSN = {1540-7063},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21669832},
Abstract = {The ability to control the flow of water around the body
dictates the performance of marine mammals in the aquatic
environment. Morphological specializations of marine mammals
afford mechanisms for passive flow control. Aside from the
design of the body, which minimizes drag, the morphology of
the appendages provides hydrodynamic advantages with respect
to drag, lift, thrust, and stall. The flukes of cetaceans
and sirenians and flippers of pinnipeds possess geometries
with flexibility, which enhance thrust production for high
efficiency swimming. The pectoral flippers provide
hydrodynamic lift for maneuvering. The design of the
flippers is constrained by performance associated with
stall. Delay of stall can be accomplished passively by
modification of the flipper leading edge. Such a design is
exhibited by the leading edge tubercles on the flippers of
humpback whales (Megaptera novaeangliae). These novel
morphological structures induce a spanwise flow field of
separated vortices alternating with regions of accelerated
flow. The coupled flow regions maintain areas of attached
flow and delay stall to high angles of attack. The delay of
stall permits enhanced turning performance with respect to
both agility and maneuverability. The morphological features
of marine mammals for flow control can be utilized in the
biomimetic design of engineered structures for increased
power production and increased efficiency.},
Doi = {10.1093/icb/icn029},
Key = {Fish08}
}
@article{fds281380,
Author = {Schindera, ST and Nelson, RC and Howle, L and Nichols, E and DeLong, DM and Merkle, EM},
Title = {Effect of varying injection rates of a saline chaser on
aortic enhancement in CT angiography: phantom
study.},
Journal = {European Radiology},
Volume = {18},
Number = {8},
Pages = {1683-1689},
Publisher = {Springer Nature},
Year = {2008},
Month = {August},
ISSN = {0938-7994},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18351346},
Abstract = {The effect of varying injection rates of a saline chaser on
aortic enhancement in computed tomography (CT) angiography
was determined. Single-level, dynamic CT images of a
physiological flow phantom were acquired between 0 and 50 s
after initiation of contrast medium injection. Four
injection protocols were applied with identical contrast
medium administration (150 ml injected at 5 ml/s). For
baseline protocol A, no saline chaser was applied. For
protocols B, C, and D, 50 ml of saline was injected at 2.5
ml/s, 5 ml/s, and 10 ml/s, respectively. Injecting the
saline chaser at twice the rate as the contrast medium
yielded significantly higher peak aortic enhancement values
than injecting the saline at half or at the same rate as the
contrast medium (P < 0.05). Average peak aortic enhancement
(HU) measured 214, 214, 218, and 226 for protocols A, B, C,
and D, respectively. The slower the saline-chaser injection
rate, the longer the duration of 90% peak enhancement: 13.6,
12.2, and 11.7 s for protocols B, C, and D, respectively (P
> 0.05). In CT angiography, saline chaser injected at twice
the rate as the contrast medium leads to increased peak
aortic enhancement and saline chaser injected at half the
rate tends towards prolonging peak aortic enhancement
plateau.},
Doi = {10.1007/s00330-008-0911-3},
Key = {fds281380}
}
@article{fds192606,
Author = {Vann, R.D. and Howle, L.E. and Dunford, R.G. and Denoble,
P.D.},
Title = {The optimal path},
Journal = {Decompression and the Deep Stop Workshop
Proceedings},
Publisher = {Undersea and Hyperbaric Medical Society},
Address = {Salt Lake City, UT},
Year = {2008},
Month = {June},
Key = {fds192606}
}
@article{fds192659,
Author = {Coursey, C. and Nelson, R.C. and Weber, P.W. and Nichols, E. and Marin, D. and Howle, L.E.},
Title = {Ultrafast multidetector CT angiography of the chest and
abdomen: How do alterations in rates of contrast media and
saline chaser injection and alterations in cardiac output
effect peak aortic enhancement?},
Journal = {94th Scientific Assembly and Annual Meeting of the
Radiological Society of North America},
Year = {2008},
Key = {fds192659}
}
@article{fds192660,
Author = {Murray, M. and Weber, P. and Howle, L. and Fish,
F.},
Title = {Lift and Drag of Cetacean Flippers},
Journal = {61st Annual Meeting of the APS Division of Fluid
Dynamics},
Year = {2008},
Key = {fds192660}
}
@article{fds192661,
Author = {Nichols, E. and Nelson, R.C. and Schindera, S.T. and Howle,
L.E.},
Title = {Mechanical power injection of iodinates contrast media:
quantitative assessment of angiocatheter exit jet
dynamics},
Journal = {37th Annual Postgraduate Course and Scientific Meeting of
the Society of Gastrointestinal Radiologists},
Year = {2008},
Key = {fds192661}
}
@article{fds192662,
Author = {Nichols, E. and Nelson, R.C. and Schindera, S.T. and Howle,
L.E.},
Title = {Mechanical power injection of iodinated contrast media:
quantitative assessment of angiocatheter exit jet dynamics
using different injection rates and catheter
sizes},
Journal = {104th Annual Meeting of the American Roetgen Ray
Society},
Year = {2008},
Key = {fds192662}
}
@article{fds192663,
Author = {Dunford, R.G. and Denoble, P.J. and Vann, R.D. and Shannon, J.S. and Pollock, N.W. and Howle, L.E.},
Title = {The relationship of age and BMI to Doppler-detected bubble
grades},
Journal = {Proceedings of the 2008 Underwater and Hyperbaric Medical
Society Meeting},
Year = {2008},
Key = {fds192663}
}
@article{fds192664,
Author = {Vann, R.D. and Dunford, R.G. and Denoble, P.D. and Howle,
L.E.},
Title = {The probabilities of DCS and VGE after nitrogen-oxygen
diving},
Journal = {Proceedings of the 2008 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2008},
Key = {fds192664}
}
@article{fds192665,
Author = {Howle, L.E. and Weber, P.W. and Vann, R.D.},
Title = {Is marginal DCS ("niggles") real or random
noise?},
Journal = {Proceedings of the 2008 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2008},
Key = {fds192665}
}
@article{fds192666,
Author = {Vann, R.D. and Howle, L.E. and Pieper, C.F. and Denoble, P.D. and Freiberger, J.J. and Moon, R.E.},
Title = {Statistical prediction of residual DCI symptoms after
decompression},
Journal = {Proceedings of the 2008 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2008},
Key = {fds192666}
}
@article{Miklosovic2007,
Author = {Miklosovic, DS and Murray, MM and Howle, LE},
Title = {Experimental evaluation of sinusoidal leading
edges},
Journal = {Journal of Aircraft},
Volume = {44},
Number = {4},
Pages = {1404-1408},
Publisher = {American Institute of Aeronautics and Astronautics
(AIAA)},
Year = {2007},
Month = {January},
ISSN = {0021-8669},
url = {http://dx.doi.org/10.2514/1.30303},
Abstract = {Experimental evaluation of the sinusoidal leading-edge (LE)
planforms on an NACA 63-021 airfoil section are discussed.
The larger amplitude sinusoids created 'softer' stall
characteristics by maintaining attached flow at the peaks
despite separated flow in the troughs. The addition of LE
tubercles to a three dimensional (3D) idealized flipper
increased the maximum lift coefficient while reducing the
drag coefficient over a portion of the operational envelope.
The effects of extending the stall point for lifting
surfaces at similar Reynolds numbers is considered to have
application to small-unmanned aerial vehicle (UAV). The
substantial loss in lift and increase in drag means that the
scallops had largely a 3-D benefit that is a function of the
planform shape and the Reynolds number. A flat poststall
lift curve as seen in the full-span test results is
considered to be beneficial when the blades are operating in
the neighborhood of the stall angle for lower speed,
unsteady winds.},
Doi = {10.2514/1.30303},
Key = {Miklosovic2007}
}
@article{fds192667,
Author = {Howle, L.E. and Weber, P.W. and Vann, R.D.},
Title = {A parameter estimation system with computational advantages
for fitting probabilistic decompression models to empirical
data},
Journal = {Proceedings of the 2007 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2007},
Key = {fds192667}
}
@article{fds192668,
Author = {Howle, L.E. and Weber, P.W. and Vann, R.D.},
Title = {A parameter estimation system with computational advantages
for fitting probabilistic decompression models to empirical
data},
Journal = {Proceedings of the 2007 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2007},
Key = {fds192668}
}
@article{fds192669,
Author = {Weber, P.W. and Howle, L.E. and Vann, R.D. and Pieper,
F.C.},
Title = {Probability models of mild and serious decompression
sickness (DCS)},
Journal = {Proceedings of the 2007 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2007},
Key = {fds192669}
}
@article{fds192670,
Author = {Howle, L.E. and Lebental, S. and Vann, R.D.},
Title = {Optimization of probabilistic decompression
models},
Journal = {Proceedings of the 2006 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2006},
Key = {fds192670}
}
@article{fds192671,
Author = {Vann, R.D. and Lebental, S. and Howle, L.E.},
Title = {The relative roles of surface tension and the oxygen window
in bubble resolution},
Journal = {Proceedings of the 2006 Undersea and Hyperbaric Medical
Society Meeting},
Year = {2006},
Key = {fds192671}
}
@article{fds192607,
Author = {Murray, M.M. and Miklosovic, D.A. and Fish, F. and Howle,
L.E.},
Title = {Effects of leading edge tubercles on a representative whale
flipper model at various sweep angles},
Journal = {14th International Symposium on Unmanned Untethered
Submersible Technology},
Address = {Durham, NH},
Year = {2005},
Month = {August},
Key = {fds192607}
}
@article{fds192672,
Author = {Murray, M. and Howle, L.E.},
Title = {Cavitation inception on rudder models with smooth and
scalloped leading edges},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {2005},
Key = {fds192672}
}
@article{Miklosovic2004,
Author = {Miklosovic, DS and Murray, MM and Howle, LE and Fish,
FE},
Title = {Leading-edge tubercles delay stall on humpback whale
(Megaptera novaeangliae) flippers},
Journal = {Physics of Fluids},
Volume = {16},
Number = {5},
Pages = {L39-L42},
Publisher = {AIP Publishing},
Year = {2004},
Month = {January},
ISSN = {1070-6631},
url = {http://dx.doi.org/10.1063/1.1688341},
Abstract = {The humpback whale (Megaptera novaeangliae) is exceptional
among the baleen whales in its ability to undertake
acrobatic underwater maneuvers to catch prey. In order to
execute these banking and turning maneuvers, humpback whales
utilize extremely mobile flippers. The humpback whale
flipper is unique because of the presence of large
protuberances or tubercles located on the leading edge which
gives this surface a scalloped appearance. We show, through
wind tunnel measurements, that the addition of leading-edge
tubercles to a scale model of an idealized humpback whale
flipper delays the stall angle by approximately 40%, while
increasing lift and decreasing drag. © 2004 American
Institute of Physics.},
Doi = {10.1063/1.1688341},
Key = {Miklosovic2004}
}
@booklet{Fish03,
Author = {Fish, FE and Miklosovic, DS and Murray, MM and Howle,
LE},
Title = {Delayed stall due to leading edge tubercles of the humpback
whale flipper},
Journal = {Integrative and Comparative Biology},
Volume = {43},
Number = {6},
Pages = {903-903},
Publisher = {SOC INTEGRATIVE COMPARATIVE BIOLOGY},
Year = {2003},
Month = {December},
ISSN = {1540-7063},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000222235200405&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Key = {Fish03}
}
@article{Wagner2003,
Author = {Wagner, BA and Bertozzi, AL and Howle, LE},
Title = {Positive feedback control of Rayleigh-Bénard
convection},
Journal = {Discrete and Continuous Dynamical Systems Series
B},
Volume = {3},
Number = {4},
Pages = {619-642},
Publisher = {American Institute of Mathematical Sciences
(AIMS)},
Year = {2003},
Month = {November},
ISSN = {1531-3492},
url = {http://dx.doi.org/10.3934/dcdsb.2003.3.619},
Abstract = {We consider the problem of active feedback control of
Rayleigh-Bénard convection via shadowgraphic measurement.
Our theoretical studies show, that when the feedback control
is positive, i.e. is tuned to advance the onset of
convection, there is a critical threshold beyond which the
system becomes linearly ill-posed so that short-scale
disturbances are greatly amplified. Experimental observation
suggests that finite size effects become important and we
develop a theory to explain these contributions. As an
efficient modelling tool for studying the dynamics of such a
controlled pattern forming system, we use a Galerkin
approximation to derive a dimension reduced
model.},
Doi = {10.3934/dcdsb.2003.3.619},
Key = {Wagner2003}
}
@article{Murray2003,
Author = {Murray, MM and Howle, LE},
Title = {Spring stiffness influence on an oscillating
propulsor},
Journal = {Journal of Fluids and Structures},
Volume = {17},
Number = {7},
Pages = {915-926},
Publisher = {Elsevier BV},
Year = {2003},
Month = {January},
ISSN = {0889-9746},
url = {http://dx.doi.org/10.1016/S0889-9746(03)00026-4},
Abstract = {We study the propulsive dynamics of a thin foil pitching
about its quarter chord and allowed to passively plunge.
Specifically, we focus on the effect of variations in
translational spring stiffness on propulsor plunge and on
the minimum oscillation frequency required to produce
positive thrust. Our numerical simulation utilizes a
two-dimensional hydroelasticity model of the propulsor-fluid
system in a constant velocity free stream. The pitch is
forced at the quarter chord by a drive shaft and the
dynamics of the fluid-structure interaction coupled to the
strength of a translational spring determines the plunge
amplitude. We use an unsteady two-dimensional vortex lattice
method to model the hydrodynamics of the propulsor producing
thrust in a potential flow field. The phase relationship
between the driving angle and the plunge displacement is
discussed, along with the effects of changing spring
stiffness on thrust and efficiency. We show that passive
plunge reduces the critical frequency for positive thrust
production. This allows simple one-actuator input to compete
with more complicated two-actuator systems. © 2003 Elsevier
Ltd. All rights reserved.},
Doi = {10.1016/S0889-9746(03)00026-4},
Key = {Murray2003}
}
@article{fds192673,
Author = {Murray, M. and Miklosovic, D. and Fish, F. and Howle,
L.},
Title = {Stall delay by leading edge tubercle in humpback whale
flipper},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {2003},
Key = {fds192673}
}
@article{02457184256,
Author = {Hasik, MJ and Kim, DH and Howle, LE and Needham, D and Prush,
DP},
Title = {Evaluation of synthetic phospholipid ultrasound contrast
agents.},
Journal = {Ultrasonics},
Volume = {40},
Number = {9},
Pages = {973-982},
Year = {2002},
Month = {November},
ISSN = {0041-624X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12385954},
Keywords = {Ultrasonics;Agents;Carbon;Benchmarking;Backscattering;Echocardiography;Proteins;Dissolution;},
Abstract = {The echogenic properties of synthetic, phospholipid
encapsulated, air-filled microbubbles with various
carbon-chain length as ultrasound contrast agents are
investigated through the use of a flow-through laboratory
ultrasound system. Specifically, we investigate the effect
of shell carbon-chain length on the ultrasonic signal for a
variety of flow rates. Averaged, integrated backscatter
power measurements from the lipid encapsulated agents are
benchmarked against those of Albunex (Albunex is a
registered trademark of Molecular Biosystems, Inc., San
Diego, CA), a commercially available, air-filled protein
microbubbles contrast agent, approved for clinical use in
echocardiography in the United States by the Food and Drug
Administration. We find that the lipid encapsulated agents
sustain less damage leading to gas dissolution or particle
destruction as compared to Albunex in the slow-flow studies
performed. The carbon-chain length of the encapsulating
lipid molecule is shown not to observably affect the
backscattered amplitude of ultrasound at flow velocities
exceeding 7 mm/s.},
Doi = {10.1016/s0041-624x(02)00384-0},
Key = {02457184256}
}
@article{fds192608,
Author = {Martin, J.I. and Howle. L.E. and Murray, M.M.},
Title = {Optimization of undulatory flap propulsors},
Journal = {12th International Symposium on Unmanned Untethered
Submersible Technology},
Address = {Durham, NH},
Year = {2001},
Month = {August},
Key = {fds192608}
}
@article{fds192609,
Author = {Moore, N.J. and Howle. L.E. and Murray, M.M.},
Title = {Controlling an output wave shape during undulatory
swimming},
Journal = {12th International Symposium on Unmanned Untethered
Submersible Technology},
Address = {Durham, NH},
Year = {2001},
Month = {August},
Key = {fds192609}
}
@article{fds192610,
Author = {Murray, M.M. and Howle, L.E.},
Title = {Response of compliant foils to dynamic loadings produced by
oncoming vorticies},
Journal = {12th International Symposium on Unmanned Untethered
Submersible Technology},
Address = {Durham, NH},
Year = {2001},
Month = {August},
Key = {fds192610}
}
@article{6674901,
Author = {Howle, LE},
Title = {The effect of boundary properties on controlled
Rayleigh-Benard convection},
Journal = {Journal of Fluid Mechanics},
Volume = {411},
Pages = {39-58},
Publisher = {Cambridge University Press (CUP)},
Year = {2000},
Month = {May},
url = {http://dx.doi.org/10.1017/S0022112099007910},
Keywords = {Benard convection;bifurcation;boundary layers;thermal
conductivity;thermal diffusivity;},
Abstract = {We investigate the effect of the finite horizontal boundary
properties on the critical Rayleigh and wave numbers for
controlled Rayleigh-Benard convection in an infinite
horizontal domain. Specifically, we examine boundary
thickness, thermal diffusivity and thermal conductivity. Our
control method is through perturbation of the lower-boundary
heat flux. A linear proportional-differential control method
uses the local amplitude of a shadowgraph to actively
redistribute the lower-boundary heat flux. Realistic
boundary conditions for laboratory experiments are selected.
Through linear stability analysis we examine, in turn, the
important boundary properties and make predictions of the
properties necessary for successful control experiments. A
surprising finding of this work is that for certain
realistic parameter ranges, one may find an isola to
time-dependent convection as the primary
bifurcation.},
Doi = {10.1017/S0022112099007910},
Key = {6674901}
}
@article{6468250,
Author = {Chen, D and Wang, HO and Howle, LE},
Title = {Bifurcation control of Rayleigh-Benard convection},
Journal = {Ieee Conference on Control Applications Proceedings},
Volume = {1},
Pages = {377-382},
Address = {Kohala Coast, HI, USA},
Year = {1999},
Month = {December},
url = {http://dx.doi.org/10.1109/CCA.1999.806663},
Keywords = {Benard convection;bifurcation;fluid mechanics;limit
cycles;multidimensional systems;nonlinear systems;partial
differential equations;},
Abstract = {Bifurcation control deals with the modification of the
bifurcation characteristics of a parameterized nonlinear
system by a judiciously designed control input. In this
paper, we investigate the problem of active control of
Rayleigh-Benard convection (RBC) via a bifurcation control
approach. Active control of Rayleigh-Benard convection is a
problem of importance to both theoretical research and
industrial applications. Several forms of bifurcation
control laws are designed based on the mathematical analysis
of the governing partial differential equations for RBC.
Simulations as well as experimental studies have been
carried out to validate the control designs. A composite
bifurcation control law combining a linear control law and a
cubic control law is found to be most effective and flexible
for this problem.},
Key = {6468250}
}
@article{99074715653,
Author = {Gustafson, MR and Howle, LE},
Title = {Effects of anisotropy and boundary plates on the critical
values of a porous medium heated from below},
Journal = {International Journal of Heat and Mass Transfer},
Volume = {42},
Number = {18},
Pages = {3419-3430},
Publisher = {Elsevier BV},
Year = {1999},
Month = {September},
url = {http://dx.doi.org/10.1016/S0017-9310(99)00028-9},
Keywords = {Porous materials;Anisotropy;Plates (structural
components);Thermal diffusion in solids;Mechanical
permeability;},
Abstract = {We present a linear stability analysis of
Horton-Rogers-Lapwood convection in an anisotropic porous
medium bounded by finite-property plates of infinite
horizontal extent. Critical values for the onset of
convection are obtained using a continuation method. These
values are compared with experimental data. The effects of
plate diffusivity, plate diffusivity, plate thickness, and
anisotropy in the diffusivity and permeability of the porous
medium on these critical values are explored. We find that
the predicted critical values from our stability analysis
agree favorably with available precision experimental
measurements.},
Doi = {10.1016/S0017-9310(99)00028-9},
Key = {99074715653}
}
@article{fds192611,
Author = {L.E. Howle},
Title = {Undulatory Flap Propulsion},
Journal = {11th International Symposium on Unmanned Untethered
Submersible Technology},
Pages = {487-493},
Address = {Durham, NH},
Year = {1999},
Month = {August},
Key = {fds192611}
}
@article{6456481,
Author = {Craciunescu, OI and Howle, LE and Clegg, ST},
Title = {Experimental evaluation of the thermal properties of two
tissue equivalent phantom materials.},
Journal = {International Journal of Hyperthermia : the Official Journal
of European Society for Hyperthermic Oncology, North
American Hyperthermia Group},
Volume = {15},
Number = {6},
Pages = {509-518},
Year = {1999},
ISSN = {0265-6736},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10598948},
Keywords = {bio-optics;biological effects of radiation;biological
tissues;calorimetry;density;hyperthermia;muscle;numerical
analysis;radiation therapy;specific heat;temperature
distribution;temperature measurement;thermal
conductivity;thermal diffusion;thermal diffusivity;},
Abstract = {Tissue equivalent radio frequency (RF) phantoms provide a
means for measuring the power deposition of various
hyperthermia therapy applicators. Temperature measurements
made in phantoms are used to verify the accuracy of various
numerical approaches for computing the power and/or
temperature distributions. For the numerical simulations to
be accurate, the electrical and thermal properties of the
materials that form the phantom should be accurately
characterized. This paper reports on the experimentally
measured thermal properties of two commonly used phantom
materials, i.e. a rigid material with the electrical
properties of human fat, and a low concentration polymer gel
with the electrical properties of human muscle.
Particularities of the two samples required the design of
alternative measuring techniques for the specific heat and
thermal conductivity. For the specific heat, a calorimeter
method is used. For the thermal diffusivity, a method
derived from the standard guarded comparative-longitudinal
heat flow technique was used for both materials. For the
'muscle'-like material, the thermal conductivity, density
and specific heat at constant pressure were measured as: k =
0.31 +/- 0.001 W(mK)(-1), p = 1026 +/- 7 kgm(-3), and c(p) =
4584 +/- 107 J(kgK)(-1). For the 'fat'-like material, the
literature reports on the density and specific heat such
that only the thermal conductivity was measured as k = 0.55
W(mK)(-1).},
Doi = {10.1080/026567399285503},
Key = {6456481}
}
@article{6295269,
Author = {Chen, D and Wang, HO and Howle, LE and Gustafson, MR and Meressi,
T},
Title = {Amplitude control of bifurcations and application to
Rayleigh-Benard convection},
Journal = {Proceedings of the Ieee Conference on Decision and
Control},
Volume = {2},
Pages = {1951-1956},
Address = {Tampa, FL, USA},
Year = {1998},
Month = {December},
url = {http://dx.doi.org/10.1109/CDC.1998.758606},
Keywords = {Benard convection;bifurcation;feedback;flow
control;nonlinear control systems;partial differential
equations;},
Abstract = {Bifurcation control deals with the modification of the
bifurcation characteristics of a parameterized nonlinear
system by a judiciously designed control input. In this
paper, we focus on the problem of controlling the amplitude
of bifurcated solutions. It is shown that the amplitude of
the bifurcated solutions is directly related to the
so-called bifurcation stability coefficient. The bifurcation
amplitude control is applied to the active control of
Rayleigh-Benard convection. Cubic feedback control laws are
designed to suppress the convection amplitude. From the
mathematical analysis of the governing partial differential
equations, two (spatially) distributed cubic control laws,
one in pseudo-spectral coordinates and one in physical
spatial coordinates, are proposed. Simulation results
demonstrate that both are able to suppress the convection
amplitude. A composite bifurcation control law combining a
linear control law and a cubic control law is considered to
be most effective and flexible for this problem.
Experimental investigations are ongoing to accompany the
theoretical findings.},
Key = {6295269}
}
@article{fds281379,
Author = {Howle, L and Schaeffer, DG and Shearer, M and Zhong,
P},
Title = {Lithotripsy: The treatment of kidney stones with shock
waves},
Journal = {Siam Review},
Volume = {40},
Number = {2},
Pages = {356-371},
Publisher = {Society for Industrial & Applied Mathematics
(SIAM)},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1137/S0036144597322630},
Abstract = {This paper discusses mathematical models for the response of
a small air bubble in water to an ultrasound pulse, a
context that arises in the modern treatment for kidney
stones. The paper reviews Rayleigh's 1917 theory for bubble
response, applies asymptotics to describe large-amplitude
solutions of Rayleigh's equations, and briefly discusses
effects neglected in the simple model. The style is
expository, intended both to introduce this application to
mathematicians and to illustrate the use of asymptotic
methods to nonmathematicians.},
Doi = {10.1137/S0036144597322630},
Key = {fds281379}
}
@article{fds192674,
Author = {L.E. Howle},
Title = {Undulatory Flap Pair Propulsion},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192674}
}
@article{fds192675,
Author = {Hasik, M.J. and Howle, L.E. and Needham, D.},
Title = {Effect of Contrast Agent’s Lipid Carbon Chain Length on
Backscattered Ultrasound Amplitude},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192675}
}
@article{fds192676,
Author = {Gustafson, M.R. and Howle, L.E. Experimental},
Title = {Control of Horton-Rogers-Lapwood Convection using
Shadowgraphic Input},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192676}
}
@article{fds192677,
Author = {Murray, M.M. and Howle, L.E.},
Title = {Translational Spring Stiffness Influence on an Oscillating
Propulsor},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192677}
}
@article{fds192678,
Author = {Gustafson, M.R. and Howle, L.E.},
Title = {Boundary Effects on the Onset of Convection in Porous
Media},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192678}
}
@article{fds192679,
Author = {Murray, M.M. and Howle, L.E.},
Title = {Reduced Order Hydroelasticity Modeling of a Flexible
Propulsor},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192679}
}
@article{fds192680,
Author = {Howle, L. E.},
Title = {Boundary Effects in Controlled Rayleigh-Bénard
Convection},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192680}
}
@article{fds192681,
Author = {Meressi, T. and Howle, L.E.},
Title = {Linear and Nonlinear Control of Rayleigh-Bénard
Convection},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1998},
Key = {fds192681}
}
@article{97043592459,
Author = {Howle, LE and Behringer, RP and Georgiadis, JG},
Title = {Convection and flow in porous media. Part 2. Visualization
by shadowgraph},
Journal = {Journal of Fluid Mechanics},
Volume = {332},
Pages = {247-262},
Publisher = {Cambridge University Press (CUP)},
Year = {1997},
Month = {February},
url = {http://dx.doi.org/10.1017/s0022112096004004},
Keywords = {Fluids;Porous materials;Heat convection;Flow
patterns;Thermal conductivity;},
Abstract = {We present results for pattern formation at the onset of
convection in fluid-saturated porous media obtained by a
novel variation on the shadowgraphic technique (modified
shadowgraphic technique). Both ordered and disordered media
are used, each exhibiting distinct behaviour. Ordered porous
media are constructed from grids of overlapping bars.
Convective onset in this type of medium is characterized by
a sharp, well-defined bifurcation to straight parallel
rolls. The orientation of the convection rolls is determined
by the number of bar layers, Nb; odd Nb leads to rolls with
axes perpendicular to the direction of the top and bottom
bars, and even Nb to rolls at 45° to the bars. Disordered
porous layers are produced by stacking randomly drilled
disks separated by spacers. In this system, we observe a
rounded bifurcation to convection with localized convection
near convective onset. More specifically, the flow patterns
take on one of several different three-dimensional cellular
structures after each cycling through convective onset.
These observations may be described by two different
mechanisms: random spatial fluctuations in the Rayleigh
number (Zimmermann et al. 1993), and/or spatial variation in
the thermal conductivity on the length scale of the
convection wavelength (Braester & Vadasz
1993).},
Doi = {10.1017/s0022112096004004},
Key = {97043592459}
}
@article{97123952256,
Author = {Howle, LE},
Title = {Linear stability analysis of controlled Rayleigh-Bénard
convection using shadowgraphic measurement},
Journal = {Physics of Fluids},
Volume = {9},
Number = {11},
Pages = {3111-3113},
Publisher = {AIP Publishing},
Year = {1997},
Month = {January},
ISSN = {1070-6631},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1997YE01200001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We conduct a linear stability analysis of Rayleigh-Bénard
convection in an infinite horizontal layer with active
control of the lower boundary heat flux. A simple linear
proportional control loop uses a shadowgraph of the
convection pattern to actively distribute the constant-mean
lower boundary heat flux while the upper boundary is kept at
a constant temperature. We find it possible to shift the
convection threshold by a factor of approximately 3. This is
a companion paper to our recent experimental work. © 1997,
American Institute of Physics. All rights
reserved.},
Doi = {10.1063/1.869428},
Key = {97123952256}
}
@article{97093817438,
Author = {Murray, MM and Tong, HL and Howle, LE and Zhong, P},
Title = {Response to a lithotripter shock wave of a cavitation bubble
surrounded by a viscoelastic membrane},
Journal = {American Society of Mechanical Engineers, Fluids Engineering
Division (Publication) Fed},
Volume = {21},
Pages = {6pp},
Address = {Vancouver, Can},
Year = {1997},
Month = {January},
Keywords = {Bubbles (in fluids);Cavitation;Shock waves;Membranes;Tissue;Mathematical
models;Pressure;},
Abstract = {A model is proposed for the dynamics of an in vivo
cavitation bubble. The model includes the effects of a
viscoelastic membrane. It can accurately describe bubble
dynamics when subjected to a focused shock wave
source.},
Key = {97093817438}
}
@article{97073735242,
Author = {Howle, LE},
Title = {Active control of Rayleigh-Bénard convection},
Journal = {Physics of Fluids},
Volume = {9},
Number = {7},
Pages = {1861-1863},
Publisher = {AIP Publishing},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1063/1.869335},
Abstract = {We report on stabilizing the unstable no-motion state in a
moderate aspect ratio one-dimensional Rayleigh-Bénard
convection experiment. A linear proportional control
algorithm uses shadowgraphic convection images to determine
heat flux perturbations which are applied to the lower
boundary by a network of local heaters. We show that simple
linear control stabilizes the otherwise unstable no-motion
(conduction) state over a substantial range of supercritical
Rayleigh numbers, © 1997 American Institute of
Physics.},
Doi = {10.1063/1.869335},
Key = {97073735242}
}
@article{97013479926,
Author = {Howle, LE},
Title = {Control of Rayleigh-Bénard convection in a small aspect
ratio container},
Journal = {International Journal of Heat and Mass Transfer},
Volume = {40},
Number = {4},
Pages = {817-822},
Publisher = {Elsevier BV},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1016/0017-9310(96)00174-3},
Keywords = {Fluids;Control;Feedback;Heat flux;Heating;Prandtl
number;},
Abstract = {Active control of Rayleigh-Bénard convection in small
aspect ratio horizontal layer, by perturbation of the lower
thermal boundary condition, is shown. These experiments use
a novel shadowgraphic system to measure the departure of a
high Prandtl number fluid from the no-motion state. A
proportional control scheme uses the shadowgraphic
information as feedback to determine the lower boundary heat
flux distribution. An array of individually controlled
heaters imposes the heating distribution. Significant
suppression of the convection amplitude is possible to at
least 10 times the critical Rayleigh number. This convection
control method provides an economical alternative to
magnetic convection suppression. Copyright © 1996 Elsevier
Science Ltd.},
Doi = {10.1016/0017-9310(96)00174-3},
Key = {97013479926}
}
@article{fds192602,
Author = {Gustafson, M.R. and Murray, M.M. and Howle, L.E.},
Title = {Active control of Rayleigh-Bénard convection in a moderate
aspect ratio container},
Journal = {Proceedings of the 1997 ASME Fluids Engineering Division
Summer Meeting},
Year = {1997},
Key = {fds192602}
}
@article{96063225477,
Author = {Howle, LE},
Title = {A comparison of the reduced Galerkin and pseudo-spectral
methods for simulation of steady Rayleigh-Bénard
convection},
Journal = {International Journal of Heat and Mass Transfer},
Volume = {39},
Number = {12},
Pages = {2401-2407},
Publisher = {Elsevier BV},
Year = {1996},
Month = {January},
url = {http://dx.doi.org/10.1016/0017-9310(95)00346-0},
Keywords = {Numerical methods;Finite difference method;Mathematical
models;Computational complexity;Equations of
motion;Linearization;},
Abstract = {A study of the computational efficiency of two numerical
methods based on a mixed finite difference-Galerkin
technique is undertaken. This study uses steady
Rayleigh-Bénard convection in a periodic container as a
model problem. The formulation and linearization of the
reduced Galerkin and pseudo-spectral methods is discussed. A
new technique for reducing the computational effort of
evaluating the convolution sums is used. It is found that
the reduced Galerkin method allows greater linearization of
the equations of fluid motion. Additionally, the reduced
Galerkin method is approximately three times faster than the
pseudo-spectral method for the problem studied. Copyright ©
1996 Elsevier Science Ltd.},
Doi = {10.1016/0017-9310(95)00346-0},
Key = {96063225477}
}
@article{fds192682,
Author = {Howle, L.E. and Behringer, R.P.},
Title = {Floquet Stability Analysis of the Onset of Convection in
Periodic Porous Media},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1996},
Key = {fds192682}
}
@article{97073731561,
Author = {Gustafson, MR and Howle, LE},
Title = {Control of Rayleigh-Benard convection in small aspect ratio
containers},
Journal = {American Society of Mechanical Engineers, Fluids Engineering
Division (Publication) Fed},
Volume = {216},
Pages = {77-81},
Address = {Hilton Head, SC, USA},
Year = {1995},
Month = {December},
Keywords = {Thermal gradients;Energy efficiency;Boundary conditions;Heat
flux;Aspect ratio;Thermodynamic stability;},
Abstract = {If the temperature gradient across a horizontal fluid layer
is great enough, Rayleigh-Benard convection (RBC) is
initiated and thermal transport is increased. Eliminating
RBC at higher than critical temperature gradient would allow
these gradients to be maintained at lower energy cost.
Conversely, causing convection to occur at a lower thermal
gradient would allow greater thermal transport at lower
temperatures. In any case, controlling RBC would optimize
many processes involving thermal gradients across fluids.
Thus, the active suppression or enhancement of convection
through selective perturbation of the thermal boundary
conditions was investigated by considering a bulk fluid
contained within a 2:1:1 rectangular cell.},
Key = {97073731561}
}
@article{94091406941,
Author = {Howle, LE},
Title = {Efficient implementation of a finite-difference/galerkin
method for simulation of large aspect ratio
convection},
Journal = {Numerical Heat Transfer, Part B: Fundamentals},
Volume = {26},
Number = {1},
Pages = {105-114},
Publisher = {Informa UK Limited},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1080/10407799408914920},
Keywords = {Finite difference method;Tensors;Mathematical
models;Boundary layers;Approximation theory;Function
evaluation;Computational methods;},
Abstract = {The efficiency of a mixed finite-difference / Galerkin
method is examined for simulation of steady two-dimensional
Rayleigh-Bénard convection of large aspect ratio. It is
found that computation time is reduced by an order of
magnitude for large-aspect-ratio systems if the summations
resulting from the formation of inner products are expanded
prior to code compilation. The expansion of the summations
is carried out by a source code utility, which writes the
expanded and simplified source. This eliminates the need to
store and multiply sparse tensors. The method extends to
large-aspect-ratio problems that would previously be
computationally impractical using the finite-difference/Galerkin
technique. © 1994 Taylor & Francis Group,
LLC.},
Doi = {10.1080/10407799408914920},
Key = {94091406941}
}
@article{94091378780,
Author = {Howle, LE and Georgiadis, JG},
Title = {Natural convection in porous media with anisotropic
dispersive thermal conductivity},
Journal = {International Journal of Heat and Mass Transfer},
Volume = {37},
Number = {7},
Pages = {1081-1094},
Publisher = {Elsevier BV},
Year = {1994},
Month = {January},
ISSN = {0017-9310},
url = {http://dx.doi.org/10.1016/0017-9310(94)90194-5},
Keywords = {Porous materials;Thermal conductivity;Anisotropy;Hydrodynamics;Tensors;},
Abstract = {A numerical simulation is undertaken in order to study the
effect of anisotropy of the effective thermal conductivity
tensor on heat transport in the porous medium
Rayleigh-Bénard problem. The momentum equation includes an
inertial drag (Forchheimer) term. The effective thermal
conductivity tensor, in the energy equation, contains an
isotropic stagnant component and a hydrodynamic dispersive
component with principal axes aligned with the local
velocity vector and with magnitude proportional to the local
velocity amplitude. A parametric study of two-dimensional
steady cellular convection reveals the following. (1)
Dispersion increases the net heat transfer after a Rayleigh
number ~ 100-200. As the degree of anisotropy of the
effective thermal conductivity is increased, the wall
averaged Nusselt number is decreased. (2) Using the
available Rayleigh number-wavenumber variation data does not
affect the divergence between simulation and experiment. ©
1994.},
Doi = {10.1016/0017-9310(94)90194-5},
Key = {94091378780}
}
@article{fds192683,
Author = {L.E. Howle},
Title = {Suppression of Natural Convection in Small Aspect Ratio
Containers},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1994},
Key = {fds192683}
}
@article{94021214765,
Author = {Howle, LE and Behringer, RP and Georgiadis, JG},
Title = {Visualization of natural convection in ordered and
disordered porous layers},
Journal = {American Society of Mechanical Engineers, Fluids Engineering
Division (Publication) Fed},
Volume = {172},
Pages = {387-395},
Address = {New Orleans, LA, USA},
Year = {1993},
Month = {December},
Keywords = {Heat convection;Porous materials;Flow interactions;Computer
simulation;Mechanical permeability;},
Abstract = {The recent Modified Shadowgraphic Technique is used to study
pattern formation of convecting flows in fluid saturated
porous layers. Both regular and random media are explored,
each exhibiting distinct primary bifurcation behavior. In
regular porous layers, consisting of grids of overlapping
bars, the preferred wave pattern at onset is parallel rolls
with roll orientation determined by bar orientation at the
upper and lower boundaries. The random medium shows a
different disorganized convection pattern with each cycling
through the onset of convection. The experimental work is
complemented by large scale numerical simulation of large
aspect ratio convection in porous layers with uniform
permeability and with spatially varying permeability. The
influence of the permeability field on pattern selection is
explored.},
Key = {94021214765}
}
@article{fds304959,
Author = {Howle, L and Behringer, RP and Georgiadis, J},
Title = {Visualization of convective fluid flow in a porous
medium},
Journal = {Nature},
Volume = {362},
Number = {6417},
Pages = {230-232},
Publisher = {Springer Nature},
Year = {1993},
Month = {January},
url = {http://dx.doi.org/10.1038/362230a0},
Abstract = {WHEN a horizontal layer of fluid is heated from below, it
may undergo Rayleigh-Benard convection (RBC), leading to the
spontaneous appearance of regular patterns of fluid flow1.
The shadow-graph technique 2, which allows visualization of
the convection patterns, has assisted in developing an
understanding of RBC. Related to RBC is convection in a
fluid permeating a porous medium (called
Horton-Rodgers-Lapwood convection or HRLC) when it is heated
from below3-7. HRLC is relevant to geothermal applications
and to flow in soils. Pattern formation in HRLC is less
easily visualized by shadowgraph techniques because of the
difficulties of transmitting light through the porous
medium. Here we show how these difficulties can be overcome
by constructing porous media in which the interfaces between
solid and liquid are either parallel or perpendicular to the
confining boundaries of the experimental system. Convection
in such a medium can be visualized using conventional
shadowgraph methods, and we compare the stationary flow
patterns observed against measurements of heat transport. ©
1993 Nature Publishing Group.},
Doi = {10.1038/362230a0},
Key = {fds304959}
}
@article{fds281378,
Author = {Howle, LE and Behringer, RP and Georgiadis, JG},
Title = {Visualization of convective fluid flow in a porous
medium},
Journal = {Nature},
Volume = {362},
Number = {7},
Pages = {230-232},
Year = {1993},
Abstract = {WHEN a horizontal layer of fluid is heated from below, it
may undergo Rayleigh-Benard convection (RBC), leading to the
spontaneous appearance of regular patterns of fluid flow.
The shadow-graph technique, which allows visualization of
the convection patterns, has assisted in developing an
understanding of RBC. Related to RBC is convection in a
fluid permeating a porous medium (called
Horton-Rodgers-Lapwood convection or HRLC) when it is heated
from below. HRLC is relevant to geothermal applications and
to flow in soils. Pattern formation in HRLC is less easily
visualized by shadowgraph techniques because of the
difficulties of transmitting light through the porous
medium. Here we show how these difficulties can be overcome
by constructing porous media in which the interfaces between
solid and liquid are either parallel or perpendicular to the
confining boundaries of the experimental system. Convection
in such a medium can be visualized using conventional
shadowgraph methods, and we compare the stationary flow
patterns observed against measurements of heat
transport.},
Key = {fds281378}
}
@article{fds192604,
Author = {Howle, L.E. and Georgiadis, J.G. and Behringer,
J.G.},
Title = {Shadowgraphic visualization of natural convection in
rectangular-grid porous layers},
Journal = {Topics in Heat Transfer},
Volume = {206},
Pages = {17-23},
Editor = {Topics in Heat Transfer},
Year = {1992},
Key = {fds192604}
}
@article{fds192684,
Author = {Howle, L.E. and Behringer, R.P. and Georgiadis,
J.G.},
Title = {Convection in Porous Media: Visualization by a Novel
Shadowgraphic Technique},
Journal = {APS Division of Fluid Dynamics Meeting},
Year = {1992},
Key = {fds192684}
}
@article{fds192685,
Author = {Howle, L.E. and Behringer, R.P. and Georgiadis,
J.G.},
Title = {Shadowgraphic Visualization of Natural Convection in
Rectangular-Grid Porous Media},
Journal = {ASME National Heat Transfer Conference},
Year = {1992},
Key = {fds192685}
}
%% Other
@misc{fds192686,
Author = {Di Muro and G., Howle and L.E. and Vann, R.D.},
Title = {Partitioned risk analysis of NAVY decompression
dives},
Pages = {818},
Publisher = {NAVSEA},
Year = {2010},
Month = {December},
Key = {fds192686}
}
@misc{fds192687,
Author = {L.E. Howle},
Title = {WhalePower Wenvor Blade. A report in the efficiency of a
WhalePower Corp. 5 meter prototype wind turbine
blade},
Pages = {16},
Publisher = {WhalePower Corporation},
Year = {2009},
Month = {January},
Key = {fds192687}
}
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