379 research outputs found
Revisiting Joan Acker's work with the support of Joan Acker
This article is a personal tribute to working with Joan Acker. I worked with Joan in 2012, helping to edit her own thoughts and reflection on how other academics evaluate and used her own theorizing, specifically her seminal work on the gender substructure and inequality regimes. However, while this article is a tribute to Joan, her work and her thinking; it is also a personal thank you to someone I will miss for her generosity and also her activism in challenging inequalities in organizations and beyond. She continues to inspire me and hopefully others to challenge for social justice. In her 80s, Joan remained committed to addressing inequalities in social relations and how these were experienced within a dynamic social and work environment. During our collaboration, she called upon academics to put theory into practice to help address visible and invisible inequalities in organizational processes. This article is inspired by that experience and it will reveal Joan's views about her own, and other academics, theorizing of her two key concepts: the gender substructure of organizations and inequality regimes in organizations and the overlap with intersectionality. This article will offer a unique opportunity to gain insight into Joan's thinking as an academic sociologist as well as a feminist activist thereby uniting Joan as a person with her concepts
Synthesis, characterization, and wear and friction properties of variably structured SiC/Si elements made from wood by molten Si impregnation
We have synthesized pre-shaped SiC/Si ceramic material elements from charcoal (obtained from wood) by impregnation with molten silicon, which takes place in a two-stage process. In the first process, a porous structure of connected micro-crystals of ÎČ-SiC is formed, while, in the second process, molten Si totally or partly infiltrates the remaining open regions. This process forms a dense material with cubic (ÎČ-)SiC crystallites, of which the majority is imbedded in amorphous Si. The synthesis of preshaped "sprocket" elements demonstrates that desired shapes of such a dense SiC/Si composite ceramic material can be achieved, thus suggesting new industrial applications. The structure and composition of numerous as-synthesized samples were characterized in detail by using a wide range of techniques. Wear and friction properties were also investigated, with polished samples. The properties found for the present samples are very promising for abrasive applications and for new generation brake systems. © 2011 Elsevier Ltd
Conversion of wooden structures into porous SiC with shape memory synthesis
Synthesis of structured silicon carbide materials can be accomplished using wooden materials as the carbon source, with various silicon impregnation techniques. We have explored the low cost synthesis of SiC by impregnation of carbon from wood with SiO gas at high temperatures, which largely retains the structure of the starting wood (shape memory synthesis). Suitably structured, porous SiC could prove to be an important type of catalyst support material. Shape memory synthesis (SMS) has earlier been tried on high surface area carbon materials. Here we have made an extensive study of SMS on carbon structures obtained from different types of wood. © 2011 Elsevier Ltd and Techna Group S.r.l
DCE Bio Detection System Final Report
The DCE (DNA Capture Element) Bio-Detection System (Biohound) was conceived, designed, built and tested by PNNL under a MIPR for the US Air Force under the technical direction of Dr. Johnathan Kiel and his team at Brooks City Base in San Antonio Texas. The project was directed toward building a measurement device to take advantage of a unique aptamer based assay developed by the Air Force for detecting biological agents. The assay uses narrow band quantum dots fluorophores, high efficiency fluorescence quenchers, magnetic micro-beads beads and selected aptamers to perform high specificity, high sensitivity detection of targeted biological materials in minutes. This final report summarizes and documents the final configuration of the system delivered to the Air Force in December 200
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Development of Millimeter-Wave Velocimetry and Acoustic Time-of-Flight Tomography for Measurements in Densely Loaded Gas-Solid Riser Flow
The MFDRC was formed in 1998 to advance the state-of-the-art in simulating multiphase turbulent flows by developing advanced computational models for gas-solid flows that are experimentally validated over a wide range of industrially relevant conditions. The goal was to transfer the resulting validated models to interested US commercial CFD software vendors, who would then propagate the models as part of new code versions to their customers in the US chemical industry. Since the lack of detailed data sets at industrially relevant conditions is the major roadblock to developing and validating multiphase turbulence models, a significant component of the work involved flow measurements on an industrial-scale riser contributed by Westinghouse, which was subsequently installed at SNL. Model comparisons were performed against these datasets by LANL. A parallel Office of Industrial Technology (OIT) project within the consortium made similar comparisons between riser measurements and models at NETL. Measured flow quantities of interest included volume fraction, velocity, and velocity-fluctuation profiles for both gas and solid phases at various locations in the riser. Some additional techniques were required for these measurements beyond what was currently available. PNNLâs role on the project was to work with the SNL experimental team to develop and test two new measurement techniques, acoustic tomography and millimeter-wave velocimetry. Acoustic tomography is a promising technique for gas-solid flow measurements in risers and PNNL has substantial related experience in this area. PNNL is also active in developing millimeter wave imaging techniques, and this technology presents an additional approach to make desired measurements. PNNL supported the advanced diagnostics development part of this project by evaluating these techniques and then by adapting and developing the selected technology to bulk gas-solids flows and by implementing them for testing in the SNL riser testbed
Hanford Tank Farms Waste Certification Flow Loop Test Plan
A future requirement of Hanford Tank Farm operations will involve transfer of wastes from double shell tanks to the Waste Treatment Plant. As the U.S. Department of Energy contractor for Tank Farm Operations, Washington River Protection Solutions anticipates the need to certify that waste transfers comply with contractual requirements. This test plan describes the approach for evaluating several instruments that have potential to detect the onset of flow stratification and critical suspension velocity. The testing will be conducted in an existing pipe loop in Pacific Northwest National Laboratoryâs facility that is being modified to accommodate the testing of instruments over a range of simulated waste properties and flow conditions. The testing phases, test matrix and types of simulants needed and the range of testing conditions required to evaluate the instruments are describe
Variable selection: current practice in epidemiological studies
Selection of covariates is among the most controversial and difficult tasks in epidemiologic analysis. Correct variable selection addresses the problem of confounding in etiologic research and allows unbiased estimation of probabilities in prognostic studies. The aim of this commentary is to assess how often different variable selection techniques were applied in contemporary epidemiologic analysis. It was of particular interest to see whether modern methods such as shrinkage or penalized regression were used in recent publications. Stepwise selection methods remained the predominant method for variable selection in publications in epidemiological journals in 2008. Shrinkage methods were not used in any of the reviewed articles. Editors, reviewers and authors have insufficiently promoted the new, less controversial approaches of variable selection in the biomedical literature, whereas statisticians may not have adequately addressed the methodâs feasibility
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