FEM model of the ohmic resistance of IP-SOFCs

In the present work, the ohmic resistance of an integrated planar-SOFC (IP-SOFC) has been evaluated by developing a model whose equations have been solved numerically through an FEM method. The model allows to estimate the distribution of voltage and current density in the cell. A comparison between simulated and experimental data of area specific resistance is reported, which shows satisfactory agreement. The mathematical model has also been used to carry out some parametric studies for optimisation purposes. Indeed, a reduction in cell pitch length and an increase in electrode thickness are predicted to lead to a reduction in ohmic losses in IP-SOFCs.     

Investigation of the thermal, mechanical, and fracture properties of alumina-epoxy composites

A combination of dynamic shear rheology, thermomechanical analysis (TMA), scanning electron microscopy (SEM), Near-Edge X-ray Absorption Fine Structure (NEXAFS), and fracture toughness testing was utilized to characterize the thermal, mechanical, chemical, and fracture properties of alumina (α-Al₂O₃)-filled epoxy resins as a function of average filler size, size distribution, particle shape, loading, and epoxy crosslink density. In general the cured properties of the filled composites were robust. Small changes in particle size, shape, and size distribution had little impact on the final properties. Resin crosslink density and filler loading were the most critical variables, causing changes in all properties. However, most applications could likely tolerate small changes in these variables also. SEM and NEXAFS characterization of the fracture surfaces revealed that the fracture occurs at the filler interface and the interfacial epoxy composition is similar to the bulk resin, indicating a weak epoxy-alumina interaction. These results are critical for implementation of particulate-filled polymer composites in practical applications because relaxed material specifications and handling procedures can be incorporated in production environments to improve efficiency.     

Comparative Study of Models on Confinement of Concrete Cylinders with Fiber-Reinforced Polymer Composites

The use of fiber-reinforced polymer (FRP) composites for strengthening and/or rehabilitation of concrete structures is gaining increasing popularity in the civil engineering community. One of the most attractive applications of FRP materials is their use as confining devices for concrete columns, which may result in remarkable increases of strength and ductility as indicated by numerous published experimental results. Despite a large research effort, a proper analytical tool to predict the behavior of FRP-confined concrete has not yet been established. Most of the available models are empirical in nature and have been calibrated against their own sets of experimental data. On the other hand, the experimental results available in the literature encompass a wide range of values of the significant variables. The objective of this work is a systematic assessment of the performance of the existing models on confinement of concrete columns with FRP materials. The study is conducted in the following steps: the experimental data on confinement of concrete cylinders with FRP available in the technical literature are classified according to the values of the significant variables; the existing empirical and analytical models are reviewed, pointing out their distinct features; the whole set of available experimental results is compared with the whole set of analytical models; and strengths and weaknesses of the various models are analyzed. Finally, a new equation is proposed to evaluate the axial strain at peak stress of FRP-confined concrete cylinders.     

Aspects of social and emotional competence in adult attention-deficit/hyperactivity disorder.

Social and emotional competence were evaluated using self-report and behavioral measures in adults with attention-deficit/hyperactivity disorder (ADHD) and controls. Adults with ADHD viewed themselves as less socially competent but more sensitive toward violations of social norms than controls. Films depicting emotional interactions were used to assess linguistic properties of free recall and perceived emotional intensity. Although adults with ADHD used more words to describe the scenes, they used fewer emotion-related words, despite rating the emotions depicted as more intense than did controls. In contrast, no group differences for words depicting social or cognitive processes were observed. Overall, adults with ADHD appear more aware of their problems in social versus emotional skills. Findings may have implications for improving the psychosocial functioning of these adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

成品率的预测准确度有多高

成品率预测是可制造性设计（DFM）的基础之，但它还远不止于此。IBM系统和技术群300mm半导体运营副总裁DanArmbrust说：“我们精确预测成品率的能力就是我们的经济模式。”Armbrust是SEMICON West 2007成品率论坛讨论DFM现状的三位参与者之一。与他共同参加讨论的是Synopsys公司DFM解决方案副总裁Anantha Sethuraman和Photronics公司的CTO Chris Progler。     

Can being scared cause tummy aches? Naive theories, ambiguous evidence, and preschoolers' causal inferences.

Causal learning requires integrating constraints provided by domain-specific theories with domain-general statistical learning. In order to investigate the interaction between these factors, the authors presented preschoolers with stories pitting their existing theories against statistical evidence. Each child heard 2 stories in which 2 candidate causes co-occurred with an effect. Evidence was presented in the form: AB→E; CA→E; AD→E; and so forth. In 1 story, all variables came from the same domain; in the other, the recurring candidate cause, A, came from a different domain (A was a psychological cause of a biological effect). After receiving this statistical evidence, children were asked to identify the cause of the effect on a new trial. Consistent with the predictions of a Bayesian model, all children were more likely to identify A as the cause within domains than across domains. Whereas 3.5-year-olds learned only from the within-domain evidence, 4- and 5-year-olds learned from the cross-domain evidence and were able to transfer their new expectations about psychosomatic causality to a novel task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neutron Reflectometry Characterization of Interface Width between Sol-Gel Titanium Dioxide and Silicon Dioxide Thin Films

Neutron reflectometry (NR) was used to directly measure the interface width between a titanium dioxide and a silicon dioxide film deposited by sol-gel processing. In a bilayer heated to 450°C, NR measurements showed that the interface width is 0.8 nm. This width is the same as the roughness of a sol-gel silicon dioxide surface after the same heat treatment, suggesting no interdiffusion or mixing at the bilayer interface.     

Thermal Diffusivity/Conductivity and Specific Heat of Mullite-Zirconia-Silicon Carbide Whisker Composites

The thermal diffusivity of mullite-ZrO₂-SiC_w materials was determined from 25° to 1000°C for composites in which the ZrO₂ had different amounts of monoclinic and tetragonal phase, and varying SiC _w content. At 25°C the thermal diffusivity of the matrix materials increased with increasing amounts of monoclinic phase, and little or no anisotropy was seen. Composites with SiC _w additions showed significant increases in thermal diffusivity and anisotropy as compared with the matrix materials. With increasing temperature, thermal diffusivities of the matrices and their respective composites decreased, and at 1000°C differences were small. Specific heat was determined from 25° to 700°C and thermal conductivity values calculated. Specific heat increased with temperature and was not composition dependent, except for one sample. Thermal conductivity values as a function of temperature followed the same trends as the thermal diffusivity values.     

The 3DP: a processor architecture for three-dimensionalapplications

The 3DP (3-Dimensional Processor), a parallel-computing architecture that targets problems that have a 3-D numerical structure and require numerous calculations on 3-D vectors, is described. The 3DP architecture differs from traditional scalar architectures in that it operates directly on vectors. It differs from general parallel architectures in that it can solve problems that predict the behavior of highly coupled systems, and it differs from vector architectures in that it runs efficiently on length-3 vectors. Object-oriented programming on the 3DP and programming the 3DP in C++ are discussed. 3DP performance is reviewed, and the current implementation of the 3DP architecture, as an attached processor that plugs directly into Sun host VMEbus, is described     

Peritraumatic dissociation and posttraumatic stress in male Vietnam theater veterans

OBJECTIVE: The aim of this study was to determine the reliability and validity of a proposed measure of peritraumatic dissociation and, as part of that effort, to determine the relationship between dissociative experiences during disturbing combat trauma and the subsequent development of posttraumatic stress disorder (PTSD). METHOD: A total of 251 male Vietnam theater veterans from the Clinical Examination Component of the National Vietnam Veterans Readjustment Study were examined to determine the relationship of war zone stress exposure, retrospective reports of dissociation during the most disturbing combat trauma events, and general dissociative tendencies with PTSD case determination. RESULTS: The total score on the Peritraumatic Dissociation Experiences Questionnaire--Rater Version was strongly associated with level of posttraumatic stress symptoms, level of stress exposure, and general dissociative tendencies and weakly associated with general psychopathology scales from the MMPI-2. Logistic regression analyses supported the incremental value of dissociation during trauma, over and above the contributions of level of war zone stress exposure and general dissociative tendencies, in accounting for PTSD case determination. CONCLUSIONS: These results provide support for the reliability and validity of the Peritraumatic Dissociation Experiences Questionnaire--Rater Version and for a trauma-dissociation linkage hypothesis: the greater the dissociation during traumatic stress exposure, the greater the likelihood of meeting criteria for current PTSD.