10,667 research outputs found
Institutionalized Discrimination in the Legal System: A Socio-Historical Approach
Despite many of the social, political, and economic changes of the 1960s, discrimination is still prevalent in the United States. Increasingly, evidence of discrimination can be seen in our nation\u27s courts, institutions of higher education, in public policy decisions, and every social, political and economic institution. The question of how this can be in these days of ethnic and cultural diversity has aroused considerable interest among social scientists, as well as among the general public. One area that has been the target of considerable research is the criminal justice system. Wilbanks[1] has suggested that it is a myth that the criminal justice system is racist and discriminates against blacks and other minorities. This paper argues to the contrary. It is suggested that Wilbanks has inappropriately applied a microlevel analysis to a macrolevel phenomenon. Examining the historical-structural nature of the legal systems points to great disparities in the status quo of US jurisprudence
Survey and analysis of research on supersonic drag-due-to-lift minimization with recommendations for wing design
A survey of research on drag-due-to-lift minimization at supersonic speeds, including a study of the effectiveness of current design and analysis methods was conducted. The results show that a linearized theory analysis with estimated attainable thrust and vortex force effects can predict with reasonable accuracy the lifting efficiency of flat wings. Significantly better wing performance can be achieved through the use of twist and camber. Although linearized theory methods tend to overestimate the amount of twist and camber required for a given application and provide an overly optimistic performance prediction, these deficiencies can be overcome by implementation of recently developed empirical corrections. Numerous examples of the correlation of experiment and theory are presented to demonstrate the applicability and limitations of linearized theory methods with and without empirical corrections. The use of an Euler code for the estimation of aerodynamic characteristics of a twisted and cambered wing and its application to design by iteration are discussed
Towards reproducible research of event detection techniques for Twitter
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Hydrogen Generation Catalyzed by Fluorinated Diglyoxime−Iron Complexes at Low Overpotentials
Fe^(II) complexes containing the fluorinated ligand 1,2-bis(perfluorophenyl)ethane-1,2-dionedioxime (dAr^FgH_2; H = dissociable proton) exhibit relatively positive Fe^(II/I) reduction potentials. The air-stable difluoroborated species [(dAr^FgBF_2)_2Fe(py)_2] (2) electrocatalyzes H_2 generation at −0.9 V vs SCE with i_(cat)/i_p ≈ 4, corresponding to a turnover frequency (TOF) of ~ 20 s^(–1) [Faradaic yield (FY) = 82 ± 13%]. The corresponding monofluoroborated, proton-bridged complex [(dArFg2H-BF2)Fe(py)2] (3) exhibits an improved TOF of ~ 200 s^(–1) (i_(cat)/i_p ≈ 8; FY = 68 ± 14%) at −0.8 V with an overpotential of 300 mV. Simulations of the electrocatalytic cyclic voltammograms of 2 suggest rate-limiting protonation of an Fe“0” intermediate (k_(RLS) ≈ 200 M^(–1) s^(–1)) that undergoes hydride protonation to form H_2. Complex 3 likely reacts via protonation of an Fe^I intermediate that subsequently forms H_2 via a bimetallic mechanism (k_(RLS) ≈ 2000 M^(–1) s^(–1)). 3 catalyzes production at relatively positive potentials compared with other iron complexes
A Systems Theory Perspective
Aktualisierung: Am 12. Oktober 2018 wurde die digitale Version des Buchbeitrags um den fehlenden Teil (Seiten 53-66) ergänzt
Multi-Scale Diagnosis of Lithium-Ion Batteries Using Correlative Dilatometric, Acoustic and X-ray Imaging Techniques
There are growing concerns over the environmental, climate and health impacts associated with the use of non-renewable fossil fuels. Therefore, affordable, renewable energy storage devices are becoming increasingly critical as a necessary route to transition to a clean energy ecosystem. In particular, lithium-ion batteries (LiBs) as a storage solution would enable renewable energy generation to be stored until required. To overcome the limitations of LiBs in performance, capacity, power and lifetime, it is important to understand the degradation mechanism of LiB electrodes. For example, during battery operation, electrodes undergo bulk volume changes that can exacerbate electrode strain and particle cracking, which in turn contribute to the electrode’s cumulative degradation. Hence, understanding how electrodes dilate can be of critical value in improving the durability of these energy storage devices.
In this thesis, in-situ electrochemical dilatometry (ECD) will be carried out in combination with microscopy techniques, such as scanning emission microscopy (SEM) and X-ray computed tomography (X-ray CT), to investigate bulk volume changes of LiB electrodes. X-ray CT will be carried out across multiple length-scales to allow visual interpretation of the entire cell architecture and electrode morphology. Image-based modelling and quantification of X-ray images will be carried out to reveal physical parameters of electrodes such as porosity and surface area. Finally, acoustic measurements will reveal the physical changes undergone by LiBs during operation.
The experiments reported in this work successfully demonstrate a multi-scale approach to assessing the degradation mechanisms undergone by LiBs during operation, from an electrode to whole cell assemblies. Insights from ECD and acoustic measurements can be used to inform electrode design in future generation LiBs
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