7,298 research outputs found
Some properties of aqueous solutions of cetyl trimethyl ammonium bromide in the presence of substituted benzoic acid salts
This work is chiefly concerned with the properties of aqueous solutions of cetyl trimethyl ammonium bromide (CTAB) in the presence of certain additives which are mainly derivatives of benzoic acid such as sodium salicylate or sodium p-chlorobenzoate. In the first part of the work, the adsorption of CTAB from its aqueous solutions on to graphite alumina, titanium dioxide and silica has been studied. In all cases, the CTAB appears to be adsorbed by an ion exchange process. A bimolecular layer is formed. In the first layer, the ionic head of the CTA+ is held to the surface by chemical forces while the paraffin chain is oriented away from the surface and in the second layer, the reverse orientation occurs. The effect of seven benzoic acid salts on the amount of CTA+ adsorbed on alumina has been found to be qualitatively related to their effects on the viscosity of CTAB solutions. The sodium salicylate - CTAB system has been examined in more detail and an adsorbed film containing equimolecular amounts of salicylate and CTA+ has been found to form on alumina. The salicylate - CTA+ complex covers a greater part of the surface than the CTA+ alone and consequently gives a better measure of the surface area of the powder. The sedimentation volume of titanium dioxide in CTAB solutions has also been investigated and the effect of sodium salicylate y sodium p-chlorobenzoate and sodium p-hydroxybenzoate on this sedimentation volume has been related to their effects on the viscosity of CTAB solutions. In the second part of the work, the approximate activity coefficient of Br in CTAB solutions was measured using electrolytically prepared silver-silver bromide electrodes. The critical micelle concentrations of CTAB (in .002M KBr) and of dodecyl trimethyl ammonium bromide were determined by this method and found to agree with the values obtained by other workers. The activity coefficient of Br was also measured in solutions containing CTAB and salts similar to those used in the adsorption and sedimentation work. Changes in the activity coefficient of Br on addition of these salts were again found to be related to their effects of the viscoity of CTAB solutions. Finally, a preliminary attempt was made to investigate the elastic properties of the visco-elastic solutions. These solutions were contained in the gap between two vertical co-axial glass cylinders which were caused to oscillate harmonically. The response of the liquid was observed by focussing a microscope on a very small bead which had been suspended in the liquid. The results again showed that the salicylate -CTA+ complex acquires some stability when the salicylate and the CTA+ are present in equimolecular amounts. The structure of the solutions, particularly the p-chlorobenzoate - CTA+ solutions, seems to be altered on shearing. An effort has been made to interpret the results of different types of experiments in terms of long threadlike aggregates formed by interaction of the CTA+ with the organic salt
Exploring More-Coherent Quantum Annealing
In the quest to reboot computing, quantum annealing (QA) is an interesting
candidate for a new capability. While it has not demonstrated an advantage over
classical computing on a real-world application, many important regions of the
QA design space have yet to be explored. In IARPA's Quantum Enhanced
Optimization (QEO) program, we have opened some new lines of inquiry to get to
the heart of QA, and are designing testbed superconducting circuits and
conducting key experiments. In this paper, we discuss recent experimental
progress related to one of the key design dimensions: qubit coherence. Using
MIT Lincoln Laboratory's qubit fabrication process and extending recent
progress in flux qubits, we are implementing and measuring QA-capable flux
qubits. Achieving high coherence in a QA context presents significant new
engineering challenges. We report on techniques and preliminary measurement
results addressing two of the challenges: crosstalk calibration and qubit
readout. This groundwork enables exploration of other promising features and
provides a path to understanding the physics and the viability of quantum
annealing as a computing resource.Comment: 7 pages, 3 figures. Accepted by the 2018 IEEE International
Conference on Rebooting Computing (ICRC
Mental Disorder, Substance Use and Criminal Justice Contact
In May 2003, the Minister of State for Mental Health brought together representatives from Ministry of Health Services (MOHS), Ministry of Children and Family Development (MCFD), Ministry of Attorney General (MAG) and the Ministry for Public Safety and Solicitor General (MPSSG) to address the prevalence of people with mental and substance use disorders who are involved in the justice system. The result was a cross-ministry commitment to develop a report about mentally disordered offenders in the justice system in order to identify the high priority and long-term issues for this population and provide recommendations to address these concerns. The many challenges associated with mental health, substance use and the justice system are recognized world wide, and a number of reforms are underway in different jurisdictions. Invariably, these reforms reflect a combination of local needs, resources, legislation and a consideration of available evidence. A critical first step in the process of reform is careful review of available information. In British Columbia, the provincial government has formed an interministerial steering committee, with research support provided through the University of British Columbia. The UBC team, in collaboration with other experts in Canada and abroad, collected and analysed information in the following formats: Literature Review: A scholarly review of the international literature. To our knowledge, this is the most comprehensive review available of the professional literature pertaining to mental disorders, substance use disorders and criminal justice contact. Survey of Other Jurisdictions: A survey highlighting areas of need and opportunities for reform in jurisdictions across Canada and elsewhere. BC Data Analysis: A report examining the administrative data for addressing mental illness and substance use in relation to the justice system in BC. These analyses are based on an unprecedented linkage of administrative information concerning corrections and health services for the population. In 1999/2000, there were 52,000 individuals (43,859 adults and 8,234 youth) involved with the provincial corrections system. Almost 15,000 (29 percent) of the total cohort were classified as mentally disordered offenders. The prevalence rate is nearly twice the rate for the general British Columbia population.
 
Assessing U.S. Food Wastage and Opportunities for Reduction
Reducing food wastage is one of the key strategies to combat hunger and sustainably feed the world. We present a comprehensive analysis of available data, despite uncertainties due to data limitation, indicating that the U.S. loses at least 150 million metric tonnes (MMT) of food between farm and fork annually, of which about 70 MMT is edible food loss. Currently, \u3c2% of the edible food loss is recovered for human consumption. A reasonably-attainable goal of food waste reduction at the source by 20% would save more food than the annual increase in total food production and would feed millions of people. This is an opportunity of significant magnitude, offering food security and resource and environmental benefits with few negatives. Seizing this opportunity requires technological innovation, policy intervention, and public outreach. This U.S.-based analysis is pertinent to other mid- to high-income countries
Regarding Pilot Usage of Display Technologies for Improving Awareness of Aircraft System States
ed systems and the procedures for ng in complexity. This interacting trend places a larger burden on pilots to manage increasing amounts of information and to understand system interactions. The result is an increase in the likelihood of loss of airplane state awareness (ASA). One way to gain more insight into this issue is through experimentation using objective measures of visual behavior. This study summarizes an analysis of oculometer data obtained during a high-fidelity flight simulation study that included a variety of complex pilot-system interactions that occur in current flight decks, as well as several planned for the next generation air transportation system. The study was comprised of various scenarios designed to induce low and high energy aircraft states coupled with other emulated causal factors in recent accidents. Three different display technologies were evaluated in this recent pilot-in-the-loop study conducted at NASA Langley Research Center. These technologies include a stall recovery guidance algorithm and display concept, an enhanced airspeed control indication of when the automation is no longer actively controlling airspeed, and enhanced synoptic diagrams with corresponding simplified electronic interactive checklists. Multiple data analyses were performed to understand how the 26 participating airline pilots were observing ASA-related information provided during different stag specific events within these stages
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