63 research outputs found
Simulation of human thermal responses in a confined space
Latest human thermal comfort models, such as the IESD-Fiala model, are active multi-nodal
thermal models that simulate physiological regulatory responses, e.g. changing metabolic rate
and skin blood flow, shivering and sweating. Commercial CFD packages, such as ANSYS
CFX, are widely used in studying transient thermal environment. The purpose of this study is
to develop and demonstrate the method for integrating human thermal comfort models with
the CFD environment for detailed transient simulations. Different integration strategies are
discussed in this paper, as well as the technical problems with using detailed (clothed) 3-D
model in the coupled simulation. It is highlighted that further research is required to exploit
the full potential of the integrated model in environmental design
A comparison of CFD and full-scale measurements for analysis of natural ventilation
CFD modelling techniques have been used to simulate the coupled external and internal flow in a cubic
building with two dominant openings. CFD predictions of the time-averaged cross ventilation flow rates
have been validated against full-scale experimental data under various weather conditions in England.
RANS model predictions proved reliable when wind directions were near normal to the vent openings.
However, when the fluctuating ventilation rate exceeded the mean flow, RANS models were incapable of
predicting the total ventilation rate. Improved results are expected by applying more sophisticated
turbulence models, such as LES or weighted quasi-steady approximations
Supplementary document for Design method of imaging optical systems using confocal flat phase elements - 6158248.pdf
Detailed discussions of Eqs. (7) and (8) in the paper are demonstrate
Synergetic Catalytic Effect of Cu<sub>2–<i>x</i></sub>Se Nanoparticles and Reduced Graphene Oxide Coembedded in Electrospun Nanofibers for the Reduction of a Typical Refractory Organic Compound
A new heterogeneous catalytic composite
composed of nonstoichiometric Cu<sub>2–<i>x</i></sub>Se nanoparticles (NPs) with high copper deficiency and graphene oxide
(GO) is prepared by coembedding in electrospun nanofibers of a polyÂ(vinylpyrrolidone)
(PVP) support, wherein GO in the nanofibers is converted into reduced
GO (rGO) via heat treatment. The as-prepared composite Cu<sub>2–<i>x</i></sub>Se/rGO/PVP nanofibers have demonstrated superior
catalytic activity toward the reduction of a refractory organic compound
by taking 4-nitrophenol (4-NP) as an example. In the presence of NaBH<sub>4</sub>, the Cu<sub>2–<i>x</i></sub>Se/rGO/PVP nanofibers
display a synergetic effect between Cu<sub>2–<i>x</i></sub>Se and rGO in PVP nanofibers compared to their independent
components or corresponding nanofibers. Furthermore, the Cu<sub>2–<i>x</i></sub>Se/rGO/PVP nanofibers exhibit a favorable water-stable
property via heat treatment to solidify the hydrophilic PVP matrix,
which makes the composite display good reusability, stability in aqueous
solution, and separability from a water medium. This work not only
presents a direct, convenient, and effective approach to doping semiconductor
nanomaterials into polymer nanofibers but also provides fundamental
routes for further investigations about the synergetic effect between
different materials based on the platform of electrospun nanofibers
visualization2.mp4
Images seen through a transparent film-based light-field near-eye display, focusing on the droid and the foreground, or the fighter and the background. The items that are not in focus appear blurry
Electrostatic Assemblies of Well-Dispersed AgNPs on the Surface of Electrospun Nanofibers as Highly Active SERS Substrates for Wide-Range pH Sensing
Surface-enhanced
Raman scattering (SERS) has shown high promise in analysis and bioanalysis,
wherein noble metal nanoparticles (NMNPs) such as silver nanoparticles
were employed as substrates because of their strong localized surface
plasmon resonance (LSPR) properties. However, SERS-based pH sensing
was restricted because of the aggregation of NMNPs in acidic medium
or biosamples with high ionic strength. Herein, by using the electrostatic
interaction as a driving force, AgNPs are assembled on the surface
of ethylene imine polymer (PEI)/polyÂ(vinyl alcohol) (PVA) electrospun
nanofibers, which are then applied as highly sensitive and reproducible
SERS substrate with an enhancement factor (EF) of 10<sup>7</sup>–10<sup>8</sup>. When <i>p</i>-aminothiophenol (<i>p</i>-ATP) is used as an indicator with its b<sub>2</sub> mode, a good
and wide linear response to pH ranging from 2.56 to 11.20 could be
available, and the as-prepared nanocomposite fibers then could be
fabricated as excellent pH sensors in complicated biological samples
such as urine, considering that the pH of urine could reflect the
acid–base status of a person. This work not only emerges a
cost-effective, direct, and convenient approach to homogeneously decorate
AgNPs on the surface of polymer nanofibers but also supplies a route
for preparing other noble metal nanofibrous sensing membranes
Coarse-to-Fine Construction for High-Resolution Representation in Visual Working Memory
<div><p>Background</p><p>This study explored whether the high-resolution representations created by visual working memory (VWM) are constructed in a coarse-to-fine or all-or-none manner. The coarse-to-fine hypothesis suggests that coarse information precedes detailed information in entering VWM and that its resolution increases along with the processing time of the memory array, whereas the all-or-none hypothesis claims that either both enter into VWM simultaneously, or neither does.</p> <p>Methodology/Principal Findings</p><p>We tested the two hypotheses by asking participants to remember two or four complex objects. An ERP component, contralateral delay activity (CDA), was used as the neural marker. CDA is higher for four objects than for two objects when coarse information is primarily extracted; yet, this CDA difference vanishes when detailed information is encoded. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057913#s2" target="_blank">Experiment 1</a> manipulated the comparison difficulty of the task under a 500-ms exposure time to determine a condition in which the detailed information was maintained. No CDA difference was found between two and four objects, even in an easy-comparison condition. Thus, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057913#s3" target="_blank">Experiment 2</a> manipulated the memory array’s exposure time under the easy-comparison condition and found a significant CDA difference at 100 ms while replicating <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057913#s2" target="_blank">Experiment 1</a>′s results at 500 ms. In Experiment 3, the 500-ms memory array was blurred to block the detailed information; this manipulation reestablished a significant CDA difference.</p> <p>Conclusions/Significance</p><p>These findings suggest that the creation of high-resolution representations in VWM is a coarse-to-fine process.</p> </div
The complex and simple shapes used in Experiment 1.
<p>The stimuli in Category 4 were from ref. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057913#pone.0057913-Alvarez1" target="_blank">[8]</a>, and the other complex stimuli were new.</p
Results of Experiments 2.
<p>The mean accuracy (A), CDA waveforms (B), and averaged CDA amplitudes of the tested time window (C) for the exposure time of 100 ms and 500 ms. Error bars in Fig. 4A and 4C denote standard error. The CDA is a difference wave, constructed by subtracting the ipsilateral from the contralateral activity according to the cued hemifield. *indicates the difference between the two conditions was significant; whereas <i>n.s.</i> indicates the difference between the two conditions was non-significant. Grey areas of the CDA waveforms denote the tested time window.</p
Example of a change trial in the left hemifield in Experiment 1.
<p>Example of a change trial in the left hemifield in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057913#s2" target="_blank">Experiment 1</a>.</p
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