Flow and Thermal Errors in Current National Weather Service Wind Chill Models

The two National Weather Service (NWS) wind chill models in operation since 2001 have inherent errors. The first model attempted and failed to make a facial surface temperature correction on the existing Siple and Passel model. The second model, intended as an improvement on the first, erred by mistakenly defining the wind chill temperature in terms of an internal body temperature rather than the facial surface temperature. To account for a boundary-layer reduction in the free-stream velocity at head level, both models incorrectly apply a constant high-percentage reduction to this velocity as measured at the NWS 10 m level. As a result of these errors, both models predict wind chill temperatures much warmer than the actual values. These warmer temperatures can instill a public complacency whereby facial freezing is viewed as a remote possibility when in reality it may be imminent.     

Synthesis of mesoporous tungsten oxide nanofibers using the electrospinning method

Mesoporous tungsten oxide nanofibers were synthesized via a 500 °C thermal treatment of composite nanofibers prepared by electrospinning an ethanol solution consisting of tungsten ethoxide, P123 triblock copolymer, and polyvinylpyrrolidone. The as-electrospun composites exhibited unwoven nanofibers with an average diameter of 233 nm and a smooth surface morphology. During the calcination process, the composite nanofibers were shrunk to 85 nm in diameter and converted into rough, wormhole-like nanofibers. These were formed by agglomerating polycrystalline WO₃ particles of 10–30 nm along the axial direction. Furthermore, a measured pore-size distribution indicated that this nanofiber mat had different types of meso-sized porosities, which may have resulted from their wormhole-like structures and inter-fiber voids. In addition, it was observed to have the intra-grain porosity with the diameter of about 1.0 nm.     

Analytical correlation and interpretation of full scale containment specimen tests

The work presented in this paper is part of an EPRI-sponsored research program to develop experimentally verified methodology for predicting failure modes and leakage characteristics of concrete containments. This paper deals specifically with recent results of the analytical correlation and interpretation of full scale containment specimen tests. The tests under consideration are a wall/skirt-basemat specimen of a typical prestressed concrete containment, a specimen with a flawed liner to study liner crack growth, and a specimen with a typical steampipe penetration. Computational models of specimens are described, and pre-test and post-test analysis results are presented. The importance of local effects is discussed, and the role of specimen tests and analysis in failure prediction of containment structures is summarized.     

Iterative compensation schemes for multimedia content authentication

Multimedia content authentication can be achieved by deriving a fragile content-based signature from a media signal and embedding it robustly back into the signal. The perturbation due to embedding needs to be compensated with mechanisms that lead to producing the original signature. Closed form solutions for compensation are not always feasible. In this paper, we propose two iterative compensation schemes to address such scenarios. The first is based on a set-theoretic approach by using projections onto convex sets (POCS), where signature generation and signal fidelity are modeled as convex constraint sets. The other scheme uses an additive iterative approach used in the cases where the POCS approach is not applicable. Examples of successful image authentication are presented to demonstrate the effectiveness of the proposed schemes over a range of watermark-embedding robustness. A comparison with the closed-form compensation scheme, when feasible, is also presented.     

Identifying correlates of breaks in occupational sitting: a cross-sectional study

Office workers are commonly targeted in interventions to modify their sitting behaviour, yet there is limited evidence of the correlates of breaks in sitting to inform intervention development. This study identifies the individual, workplace and spatial configuration correlates of the frequency of breaks in sitting (number/hour) in office workers (n?=?5531) stratified by office type (private-enclosed, shared, open plan). All behaviours and potential correlates were measured via self-report using an online cross-sectional survey. Regression analyses revealed age was the only socio-demographic characteristic associated with frequency of breaks in sitting in all office types. Greater job autonomy and local connectivity were positively associated with frequency of breaks in sitting in shared and open-plan offices. In open-plan offices co-worker proximity was negatively associated with frequency of breaks in sitting. Co-worker visibility was positively associated with frequency of breaks in sitting in all office types. This study demonstrates that individual, workplace and spatial configuration factors are all associated with the frequency of breaks in sitting and that these relationships differ by office type. These observations extend prior studies that have only examined correlates at a single level (e.g. the individual). This evidence could be useful to guide future interventions in the design of workplaces to increase breaks in sitting and workers’ physical activity.     

Water purification from metal ions using carbon nanoparticle-conjugated polymer nanocomposites

The paper deals with a novel method of obtaining nanocarbon-conjugated polymer nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of interaction of metal ions with NCPC, ability of removing metal ions from water by NCPC against pH have been studied. NCPC has a bonding capacity of 4.0-5.7 mmol/g at pH 6 for most of the divalent metal ions. Percent of sorption of Zn²⁺, Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Cr⁶⁺ ions is higher than 99%. Lifetime of NCPC before coagulation in the treated water is 1 s-1000 min and depends on the ratio of polymeric molecules and carbon nanoparticle concentrations. Results of laboratory tests of the method are described.     

Thermal conductivity prediction of foods by Neural Network and Fuzzy (ANFIS) modeling techniques

A neuro-fuzzy modeling technique was used to predict the effective of thermal conductivity of various fruits and vegetables. A total of 676 data point was used to develop the neuro-fuzzy model considering the inputs as the fraction of water content, temperature and apparent porosity of food materials. The complexity of the data set which incorporates wide ranges of temperature (including those below freezing points) made it difficult for the data to be predicted by normal analytical and conventional models. However the adaptive neuro-fuzzy model (ANFIS) was able to predict conductivity values which closely matched the experimental values by providing lowest mean square error compared to multivariable regression and conventional artificial neural network (ANN) models. This method also alleviates the problem of determining the hidden structure of the neural network layer by trial and error.