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_2–<i>x</i>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_2–<i>x</i>Se nanoparticles (NPs) with high copper deficiency and graphene oxide (GO) is prepared by coembedding in electrospun nanofibers of a poly­(vinylpyrrolidone) (PVP) support, wherein GO in the nanofibers is converted into reduced GO (rGO) via heat treatment. The as-prepared composite Cu_2–<i>x</i>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 NaBH₄, the Cu_2–<i>x</i>Se/rGO/PVP nanofibers display a synergetic effect between Cu_2–<i>x</i>Se and rGO in PVP nanofibers compared to their independent components or corresponding nanofibers. Furthermore, the Cu_2–<i>x</i>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)/poly­(vinyl alcohol) (PVA) electrospun nanofibers, which are then applied as highly sensitive and reproducible SERS substrate with an enhancement factor (EF) of 10⁷–10⁸. When <i>p</i>-aminothiophenol (<i>p</i>-ATP) is used as an indicator with its b₂ 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