Season influence on rapid thermal sensation assessment by young adults

Thermal comfort is one of the most important ergonomic aspects of building occupancy. In this research, laboratory experiments are performed in a climatic chamber and described in detail. Experiments are carried out under two scenarios: with two different college students cohorts and with five different but comparable experimental conditions in each cohort. Three hundred twenty-two individual assessments under specific controlled thermal environment conditions are collected. The actual thermal sensation assessments obtained in the experiments are compared to the results obtained by a predicted mean vote (PMV) model. The correlation analysis shows that statistically significant differences are meaningful between the spring-summer and the autumn-winter experiments but not between genders. This paper discusses the plausible factors contributing to the different correlations experienced in the autumn-winter and spring-summer experiments. A correction factor between PMV according to Fanger's comfort equation and the actual thermal sensation values reported by the participants is also sought with a focus on the seasonal effects. The predicted results are in good agreement with the experimental results. This allows for further considerations about the influence of the season on the initial thermal sensations experienced by young adults.info:eu-repo/semantics/publishedVersio

Giant thermoelectric effect in graphene-based topological insulators with nanopores

Designing thermoelectric materials with high figure of merit $ZT=S^2 G T/\kappa$ requires fulfilling three often irreconcilable conditions, i.e., the high electrical conductance $G$, small thermal conductance $\kappa$ and high Seebeck coefficient $S$. Nanostructuring is one of the promising ways to achieve this goal as it can substantially suppress lattice contribution to $\kappa$. However, it may also unfavorably influence the electronic transport in an uncontrollable way. Here we theoretically demonstrate that this issue can be ideally solved by fabricating graphene nanoribbons with heavy adatoms and nanopores. These systems, acting as a two-dimensional topological insulator with robust helical edge states carrying electrical current, yield a highly optimized power factor $S^2G$ per helical conducting channel. Concurrently, their array of nanopores impedes the lattice thermal conduction through the bulk. Using quantum transport simulations coupled with first-principles electronic and phononic band structure calculations, the thermoelectric figure of merit is found to reach its maximum $ZT \simeq 3$ at $T \simeq 40$ K. This paves a way to design high-$ZT$ materials by exploiting the nontrivial topology of electronic states through nanostructuring.Comment: 7 pages, 4 figures; PDFLaTe

Mining, analyzing, and modeling text written on mobile devices

AbstractWe present a method for mining the web for text entered on mobile devices. Using searching, crawling, and parsing techniques, we locate text that can be reliably identified as originating from 300 mobile devices. This includes 341,000 sentences written on iPhones alone. Our data enables a richer understanding of how users type “in the wild” on their mobile devices. We compare text and error characteristics of different device types, such as touchscreen phones, phones with physical keyboards, and tablet computers. Using our mined data, we train language models and evaluate these models on mobile test data. A mixture model trained on our mined data, Twitter, blog, and forum data predicts mobile text better than baseline models. Using phone and smartwatch typing data from 135 users, we demonstrate our models improve the recognition accuracy and word predictions of a state-of-the-art touchscreen virtual keyboard decoder. Finally, we make our language models and mined dataset available to other researchers.</jats:p

Design of a UWB printed G-shaped monopole antenna using characteristic modes

© 2014 IEEE. This paper presents a novel G-shaped compact monopole UWB antenna printed on FR4 substrate with coplanar waveguide (CPW) feeding. The proposed antenna operates over the frequency band between 3 and 11 GHz offering a fractional impedance bandwidth of around 110 %. The antenna is designed by analysing the modal currents calculated using the characteristic mode theory. Experimental results on reflection coefficient agree well with simulations and the proposed antenna has a desirable gain and radiation pattern characteristics over the ultra-wideband frequency range. The overall dimensions of the antenna are 28 × 35 × 1.6 mm3 which makes it a good candidate for many ultra-wide-band radio applications