695 research outputs found
Cost Analysis of Optimized Islanded Energy Systems in a Dispersed Air Base Conflict
The United States Air Force has implemented a dispersed air base strategy to enhance mission effectiveness for near-peer conflicts. Asset dispersal places many smaller bases across a wide geographic area, which increases resupply requirements and logistical complexity. Hybrid energy systems reduce resupply requirements through sustainable, off-grid energy production. This paper presents a novel hybrid energy renewable delivery system (HERDS) model capable of (1) selecting the optimal hybrid energy system design that meets demand at the lowest net present cost and (2) optimizing the delivery of the selected system using existing Air Force cargo aircraft. The novelty of the model’s capabilities is displayed using Clark Air Base, Philippines as a case study. The HERDS model selected an optimal configuration consisting of a 676-kW photovoltaic array, an 1846-kWh battery system, and a 200-kW generator. This hybrid energy system predicts a 54% reduction in cost and an 88% reduction in fuel usage, as compared to the baseline Air Force system. The HERDS model is expected to support planners in their ongoing efforts to construct cost-effective sites that minimize the transport and logistic requirements associated with remote installations. Additionally, the results of this paper may be appropriate for broader civilian applications
Meeting Temporary Facility Energy Demand with Climate-Optimized Off-Grid Energy Systems
Remote and contingency operations, including military and disaster-relief activities, often require the use of temporary facilities powered by inefficient diesel generators that are expensive to operate and maintain. Site planners can reduce operating costs by increasing shelter insulation and augmenting generators with photovoltaic-battery hybrid energy systems, but they must select the optimal design configuration based on the region’s climate to meet the power demand at the lowest cost. To assist planners, this paper proposes an innovative, climate-optimized, hybrid energy system selection model capable of selecting the facility insulation type, solar array size, and battery backup system to minimize the annual operating cost. To demonstrate the model’s capability in various climates, model performance was evaluated for applications in southwest Asia and the Caribbean. For a facility in Southwest Asia, the model reduced fuel consumption by 93% and saved 291 thousand. This capability is expected to support planners of remote sites in their ongoing effort to minimize fuel supply requirements and annual operating costs of temporary facilities
The C-Band All-Sky Survey: Instrument design, status, and first-look data
The C-Band All-Sky Survey (C-BASS) aims to produce sensitive, all-sky maps of
diffuse Galactic emission at 5 GHz in total intensity and linear polarization.
These maps will be used (with other surveys) to separate the several
astrophysical components contributing to microwave emission, and in particular
will allow an accurate map of synchrotron emission to be produced for the
subtraction of foregrounds from measurements of the polarized Cosmic Microwave
Background. We describe the design of the analog instrument, the optics of our
6.1 m dish at the Owens Valley Radio Observatory, the status of observations,
and first-look data.Comment: 10 pages, 11 figures, published in Proceedings of SPIE MIllimeter,
Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
(2010), Vol. 7741, 77411I-1 - 77411I-1
Laboratory and tentative interstellar detection of trans-methyl formate using the publicly available Green Bank Telescope PRIMOS survey
The rotational spectrum of the higher-energy trans conformational isomer of
methyl formate has been assigned for the first time using several pulsed-jet
Fourier transform microwave spectrometers in the 6-60 GHz frequency range. This
species has also been sought toward the Sagittarius B2(N) molecular cloud using
the publicly available PRIMOS survey from the Green Bank Telescope. We detect
seven absorption features in the survey that coincide with laboratory
transitions of trans-methyl formate, from which we derive a column density of
3.1 (+2.6, -1.2) \times 10^13 cm-2 and a rotational temperature of 7.6 \pm 1.5
K. This excitation temperature is significantly lower than that of the more
stable cis conformer in the same source but is consistent with that of other
complex molecular species recently detected in Sgr B2(N). The difference in the
rotational temperatures of the two conformers suggests that they have different
spatial distributions in this source. As the abundance of trans-methyl formate
is far higher than would be expected if the cis and trans conformers are in
thermodynamic equilibrium, processes that could preferentially form
trans-methyl formate in this region are discussed. We also discuss measurements
that could be performed to make this detection more certain. This manuscript
demonstrates how publicly available broadband radio astronomical surveys of
chemically rich molecular clouds can be used in conjunction with laboratory
rotational spectroscopy to search for new molecules in the interstellar medium.Comment: 40 pages, 7 figures, 4 tables; accepted for publication in Ap
Risperidone-induced weight gain is mediated through shifts in the gut microbiome and suppression of energy expenditure
AbstractRisperidone is a second-generation antipsychotic that causes weight gain. We hypothesized that risperidone-induced shifts in the gut microbiome are mechanistically involved in its metabolic consequences. Wild-type female C57BL/6J mice treated with risperidone (80μg/day) exhibited significant excess weight gain, due to reduced energy expenditure, which correlated with an altered gut microbiome. Fecal transplant from risperidone-treated mice caused a 16% reduction in total resting metabolic rate in naïve recipients, attributable to suppression of non-aerobic metabolism. Risperidone inhibited growth of cultured fecal bacteria grown anaerobically more than those grown aerobically. Finally, transplant of the fecal phage fraction from risperidone-treated mice was sufficient to cause excess weight gain in naïve recipients, again through reduced energy expenditure. Collectively, these data highlight a major role for the gut microbiome in weight gain following chronic use of risperidone, and specifically implicates the modulation of non-aerobic resting metabolism in this mechanism
Dorsal Scapular Artery Variations And Relationship To The Brachial Plexus, And A Related Thoracic Outlet Syndrome Case
Knowledge of the relationship of the dorsal scapular artery (DSA) with the brachial plexus is limited. We report a case of a variant DSA path, and revisit DSA origins and underinvestigated relationship with the plexus in cadavers. The DSA was examined in a male patient and 106 cadavers. In the case, we observed an unusual DSA compressing the lower plexus trunk, that resulted in intermittent radiating pain and paresthesia. In the cadavers, the DSA originated most commonly from the subclavian artery (71%), with 35% from the thyrocervical trunk. Nine sides of eight cadavers (seven females) had two DSA branches per side, with one branch from each origin. The most typical DSA path was a subclavian artery origin before passing between upper and middle brachial plexus trunks (40% of DSAs), versus between middle and lower trunks (23%), or inferior (4%) or superior to the plexus (1%). Following a thyrocervical trunk origin, the DSA passed most frequently superior to the plexus (23%), versus between middle and lower trunks (6%) or upper and middle trunks (4%). Bilateral symmetry in origin and path through the brachial plexus was observed in 13 of 35 females (37%) and 6 of 17males (35%), with the most common bilateral finding of a subclavian artery origin and a path between upper and middle trunks (17%). Variability in the relationship between DSA and trunks of the brachial plexus has surgical and clinical implications, such as diagnosis of thoracic outlet syndrome
An open-source deep learning algorithm for efficient and fully-automatic analysis of the choroid in optical coherence tomography
Purpose: To develop an open-source, fully-automatic deep learning algorithm,
DeepGPET, for choroid region segmentation in optical coherence tomography (OCT)
data. Methods: We used a dataset of 715 OCT B-scans (82 subjects, 115 eyes)
from 3 clinical studies related to systemic disease. Ground truth segmentations
were generated using a clinically validated, semi-automatic choroid
segmentation method, Gaussian Process Edge Tracing (GPET). We finetuned a UNet
with MobileNetV3 backbone pre-trained on ImageNet. Standard segmentation
agreement metrics, as well as derived measures of choroidal thickness and area,
were used to evaluate DeepGPET, alongside qualitative evaluation from a
clinical ophthalmologist. Results: DeepGPET achieves excellent agreement with
GPET on data from 3 clinical studies (AUC=0.9994, Dice=0.9664; Pearson
correlation of 0.8908 for choroidal thickness and 0.9082 for choroidal area),
while reducing the mean processing time per image on a standard laptop CPU from
34.49s (15.09) using GPET to 1.25s (0.10) using DeepGPET. Both
methods performed similarly according to a clinical ophthalmologist, who
qualitatively judged a subset of segmentations by GPET and DeepGPET, based on
smoothness and accuracy of segmentations. Conclusions :DeepGPET, a
fully-automatic, open-source algorithm for choroidal segmentation, will enable
researchers to efficiently extract choroidal measurements, even for large
datasets. As no manual interventions are required, DeepGPET is less subjective
than semi-automatic methods and could be deployed in clinical practice without
necessitating a trained operator. DeepGPET addresses the lack of open-source,
fully-automatic and clinically relevant choroid segmentation algorithms, and
its subsequent public release will facilitate future choroidal research both in
ophthalmology and wider systemic health.Comment: 8 pages, 2 figures, 3 tables. Currently in submission to ARVO TVST
(Association for Research in Vision and Ophthalmology, Translational Vision
Science & Technology). GitHub link to codebase provided upon publicatio
Probing Ion-Ion and Electron-Ion Correlations in Liquid Metals within the Quantum Hypernetted Chain Approximation
We use the Quantum Hypernetted Chain Approximation (QHNC) to calculate the
ion-ion and electron-ion correlations for liquid metallic Li, Be, Na, Mg, Al,
K, Ca, and Ga. We discuss trends in electron-ion structure factors and radial
distribution functions, and also calculate the free-atom and metallic-atom
form-factors, focusing on how bonding effects affect the interpretation of
X-ray scattering experiments, especially experimental measurements of the
ion-ion structure factor in the liquid metallic phase.Comment: RevTeX, 19 pages, 7 figure
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