"THERMO": COMPUTER PROGRAM FOR SIMULATION OF SURFACE PULSE HEATING

1.IntroductionTheoneofthemostimportantparametersofthethermalcycleduringsurfacepulseheatingistherateofheatingandcooling.Knowledgeofthesevaluesinparticulartemperatureintervalshelpstoprognosticatephasestructureintheheataffectedzones(HAZ),toanalyzecausesofthestructuretransformations.Todaythereisavoluminousliteratureoncalculationofthethermalconditionsforasolidduringsurfaceprocessing.Butthetemperaturevariationsareusuallyexaminedasafunctionoftimeorspacecoordinates.Sometimesthefirstderivativeofthete…     

A conceptual spacecraft radioisotope thermoelectric and heating unit (RTHU)

Spacecraft venturing to the outer planets and beyond—or onto the planetary surface where available solar energy is reduced—benefit from the longevity and consistency of electrical and thermal energy derived from radioisotope energy sources. A review of likely mission requirements and concept studies of small electrical generating units (<10 W_e) reveals a potential opportunity for a unit with an electrical output of around 1 W_e that can also supply some heat to the spacecraft to aid thermal control: a radioisotope thermoelectric and heating unit. This power requirement cannot be achieved with current US space‐qualified modular radioisotope fuel assemblies. Additionally, new European programmes consider ²⁴¹Am fuel to be much more cost effective than ²³⁸Pu. Taken together, these factors provide the rationale for taking a relatively ‘clean‐sheet’ approach to design of a radioisotope thermoelectric and heating unit fuelled with ²⁴¹Am. In this paper, initial requirements and performance targets for such a unit are developed, a simple concept design and thermal model is presented and the performance and mass are estimated. The results suggest that units generating 1–2 W_e may achieve a specific power of around 0.7–0.9 W_e kg^?1 without the thermal inputs to spacecraft becoming impractically large. Such units can use a bismuth telluride thermoelectric material, which is commercially applied in terrestrial applications and is therefore likely to incur lower cost and development risk than more specialised compounds. This study may form the basis of a more detailed design effort. Copyright © 2011 John Wiley & Sons, Ltd.     

Progressive multifocal leukoencephalopathy in a patient with hypogammaglobulinemia

Baker's yeast reduction of methyl and ethyl (2-oxocyclohexyl) acetates proceeded with enantio- and diastereo-selectivity, affording the corresponding (2S)-trans-alcohols (major), (2S)-cis-alcohols (minor), and the unaltered (1S)-ketones with high optical purity.     

Patient-specific bronchoscopy visualization through BRDF estimation and disocclusion correction

This paper presents an image-based method for virtual bronchoscope with photo-realistic rendering. The technique is based on recovering bidirectional reflectance distribution function (BRDF) parameters in an environment where the choice of viewing positions, directions, and illumination conditions are restricted. Video images of bronchoscopy examinations are combined with patient-specific three-dimensional (3-D) computed tomography data through two-dimensional (2-D)/3-D registration and shading model parameters are then recovered by exploiting the restricted lighting configurations imposed by the bronchoscope. With the proposed technique, the recovered BRDF is used to predict the expected shading intensity, allowing a texture map independent of lighting conditions to be extracted from each video frame. To correct for disocclusion artefacts, statistical texture synthesis was used to recreate the missing areas. New views not present in the original bronchoscopy video are rendered by evaluating the BRDF with different viewing and illumination parameters. This allows free navigation of the acquired 3-D model with enhanced photo-realism. To assess the practical value of the proposed technique, a detailed visual scoring that involves both real and rendered bronchoscope images is conducted.     

Time dependence of the radiation-induced EPR signal in sucrose

Sucrose and common household sugars (e.g. cane) have been studied as dosemeters for a wide variety of applications. However, previous studies of the post-irradiation time dependence of irradiated sugar did not include an electron paramagnetic resonance (EPR) reference material. This work employs synthetic ruby as an EPR reference material to remove significant spectrometer/environmental influences on the measured time-dependent changes in the EPR spectral amplitude of irradiated sucrose. As such, these more accurate measurements should replace the previously published data.     

A protection strategy for inverter-interfaced islanded microgrids with looped configuration

Electrical Engineering - Development of an efficient protection strategy is one of the main barriers in paving the way for the implementation of inverter-based microgrids. The limited fault current...     

Finding Diachronic Like‐Minded Users

User communities in social networks are usually identified by considering explicit structural social connections between users. While such communities can reveal important information about their members such as family or friendship ties and geographical proximity, just to name a few, they do not necessarily succeed at pulling like‐minded users that share the same interests together. Therefore, researchers have explored the topical similarity of social content to build like‐minded communities of users. In this article, following the topic‐based approaches, we are interested in identifying communities of users that share similar topical interests with similar temporal behavior. More specifically, we tackle the problem of identifying temporal (diachronic) topic‐based communities, i.e., communities of users who have a similar temporal inclination toward emerging topics. To do so, we utilize multivariate time series analysis to model the contributions of each user toward emerging topics. Further, our modeling is completely agnostic to the underlying topic detection method. We extract topics of interest by employing seminal topic detection methods; one graph‐based and two latent Dirichlet allocation‐based methods. Through our experiments on Twitter data, we demonstrate the effectiveness of our proposed temporal topic‐based community detection method in the context of news recommendation, user prediction, and document timestamp prediction applications, compared with the nontemporal as well as the state‐of‐the‐art temporal approaches.