148 research outputs found
Integration of CSAB and ABET
The Accreditation Board for Engineering and Technology, Inc. (ABET) and the Computing Sciences Accreditation Board (CSAB) signed a Memorandum of Agreement in November 1998 to integrate CSAB\u27\u27s accreditation services with ABET, with a transition time of approximately two years. During the interim period, the operations of the Computer Science Accreditation Commission (CSAC) are contracted by CSAB to ABET. A committee with CSAC, CSAB, and ABET representation is working to set up the new commission for accrediting programs in the computing sciences. This new commission will probably be called the Computing Accreditation Commission (CAC). Other activities are underway to try to assure that this integration goes as smoothly as possible. This paper discusses from various points of view the current status of the integration and plans for the completion of the integration
Reduction in the Energy Cost of Minerals through at-the-face Comminution and Separation of Mineral and Waste [abstract]
Only abstract of poster available.Track III: Energy InfrastructureHigh-pressure waterjets penetrate into material through the pressurization and growth of small cracks within the target surface. In mineral ores the individual grains of the constituent components are defined by the grain boundaries and these provide such surface cracks. Eroding the ore by a stream of high-pressure water can thus exploit the cracks so that they grow, inter-connect and remove the ore on a grain by grain basis. This separates out the individual components of the ore, as the ore is mined.
Because the properties of the different mineral grains differ, either in size, density or shape they can be separated, often quite easily, at the mining machine, as the grains are collected after being removed from the face. Thus, at the point of mining, the valuable components of the ore can be separated and collected. The remaining waste minerals can then be left adjacent to the mining face, potentially being re-cemented to provide support to the ongoing excavation. This joint mining and separation process saves the cost of transporting the waste rock out of the mine, and the costs of conventional separation of the valuable material at the surface. In current practice, all the ore mined is crushed, at the surface, to a very fine powder in order to achieve liberation of the valuable mineral. As well as requiring considerably more energy this also produces a very fine waste product, which is more expensive to dispose of, often behind large tailings dams at the surface, at an environmental cost.
The use of pressurized cavitation to enhance the process, and reduce energy needs and process time is a part of this work. This new process is anticipated to drop the energy cost of mineral production by up to 60% and has been validated in laboratory and some field tests
Breakthrough Energy Savings with Waterjet Technology
Experiments performed at the University of Missouri-Rolla's Waterjet Laboratory have demonstrated clearly the ability of waterjets to disaggregate, in a single step, four different mineral ores, including ores containing iron, lead and copper products. The study focused mainly on galena-bearing dolomite, a lead ore, and compared the new technology with that of traditional mining and milling to liberate the valuable constituent for the more voluminous host rock. The technical term for the disintegration of the ore to achieve this liberation is comminution. The potential for energy savings if this process can be improved, is immense. Further, if this separation can be made at the mining face, then the potential energy savings include avoidance of transportation (haulage and hoisting) costs to move, process and store this waste at the surface. The waste can, instead, be disposed into the available cavities within the mine. The savings also include the elimination of the comminution, crushing and grinding, stages in the processing plant. Future prototype developments are intended to determine if high-pressure waterjet mining and processing can be optimized to become cheaper than traditional fragmentation by drilling and blasting and to optimize the separation process. The basic new mining process was illustrated in tests on two local rock types, a low-strength sandstone with hematite inclusions, and a medium to high-strength dolomite commonly used for construction materials. Illustrative testing of liberation of minerals, utilized a lead-bearing dolomite, and included a parametric study of the optimal conditions needed to create a size distribution considered best for separation. The target goal was to have 50 percent of the mined material finer than 100 mesh (149 microns). Of the 21 tests that were run, five clearly achieved the target. The samples were obtained as run-of-mine lumps of ore, which exhibited a great deal of heterogeneity within the samples. This, in turn, reduced the ability to apply detailed statistical tests to the product outcomes. Nonetheless, a regression analysis showed that operating pressures between 105 (10,000psi) and 140 (15,000psi) MegaPascals (MPa) at traverse speeds no greater than 10 cm/min (4 in/min), best generated the target result. Variation in other parameters, rotation speed, nozzle diameter, and nozzle separation angle, during the preliminary tests did not substantially change the product, and so were kept fixed during the ore mining tests. The experimental protocols were developed to include proper treatment of the lead-bearing materials, which may be considered hazardous. In anticipation of the creation of a mineral processing design for separation of the concentrates from the tailings (waste), assays were made of the metal content of each screen size for each of the 21 runs; with three screens and a pan for undersize, to give a total of 84 assays. This information will enable Dr. McNulty, project consultant, to create a flow sheet for the prototype mining machine. As a preliminary component to such a system, the experimental layout included a product-recovery system that delivered all of the fragmented product to the nest of screens which allowed study of the liberation at the different size levels. Where incomplete liberation is found, a secondary process was demonstrated for using pressurized cavitation to further comminute the material. This concept was successfully demonstrated, with a small cavitation chamber illustrating the much smaller space that such a tool requires, relative to conventional ball and rod mills. Additional testing is ongoing, external to this program, to find whether an one-step process using higher jet pressures and longer dwell times to achieve all the required comminution in mining, is more efficient than a two-step process in which normal jet pressures and feed rates do the initial mining, but full particle liberation is achieved only through secondary processing of the product in a cavitation chamber. Subsequent testing is also planned, to determine preferred methods for separating ore minerals from the waste. Tests with this system have included both the galena samples, and copper ores from Poland. The development of this tool lies within an expanding market for the use of high-pressure waterjet equipment across a broad spectrum of applications. As the industry develops new tools, it is anticipated that the research team will investigate the development of a prototype machine based on these tools, since this will simplify and speed up equipment development. It is hoped that once this is developed that can be taken into an active mine. Such a machine should be able to produce large enough samples to allow assessment of optimal operating conditions
Terahertz radiation shaping based on optical spectrum modulation in the time domain
This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.023117. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawA terahertz shaping system based on optical fiber components as opposed to traditional free-space solutions is proposed. It is based on the time-domain modulation of the optical source spectrum. Standard singlemode fiber distributes and disperses the pulse before filtering its spectral components by means of the cross-gain and cross-phase modulation effects taking place in an interferometric semiconductor optical amplifier structure. Experimental measurements are obtained, showing the tunability of the system as well as its reconfigurability. © 2012 Optical Society of America.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad (TEC2009-08078). Jesus Palaci is supported by the Formacion de Personal Investigador grant program of the Universidad Politecnica de Valencia.Palací López, J.; Bockelt, AS.; Vidal Rodriguez, B. (2012). Terahertz radiation shaping based on optical spectrum modulation in the time domain. Optics Express. 20(21):23117-23125. https://doi.org/10.1364/OE.20.023117S2311723125202
Negative Kaons in Dense Baryonic Matter
Kaon polarization operator in dense baryonic matter of arbitrary isotopic
composition is calculated including s- and p-wave kaon-baryon interactions. The
regular part of the polarization operator is extracted from the realistic
kaon-nucleon interaction based on the chiral and 1/N_c expansion. Contributions
of the Lambda(1116), Sigma(1195), Sigma*(1385) resonances are taken explicitly
into account in the pole and regular terms with inclusion of mean-field
potentials. The baryon-baryon correlations are incorporated and fluctuation
contributions are estimated. Results are applied for K- in neutron star matter.
Within our model a second-order phase transition to the s-wave K- condensate
state occurs at rho_c \gsim 4 \rho_0 once the baryon-baryon correlations are
included. We show that the second-order phase transition to the p-wave
condensate state may occur at densities in
dependence on the parameter choice. We demonstrate that a first-order phase
transition to a proton-enriched (approximately isospin-symmetric) nucleon
matter with a p-wave K- condensate can occur at smaller densities, \rho\lsim 2
\rho_0. The transition is accompanied by the suppression of hyperon
concentrations.Comment: 41 pages, 24 figures, revtex4 styl
A polygenic risk score analysis of psychosis endophenotypes across brain functional, structural, and cognitive domains
This large multi-center study investigates the relationships between genetic risk for schizophrenia and bipolar disorder, and multi-modal endophenotypes for psychosis. The sample included 4,242 individuals; 1,087 patients with psychosis, 822 unaffected first-degree relatives of patients, and 2,333 controls. Endophenotypes included the P300 event-related potential (N = 515), lateral ventricular volume (N = 798), and the cognitive measures block design (N = 3,089), digit span (N = 1,437), and the Ray Auditory Verbal Learning Task (N = 2,406). Data were collected across 11 sites in Europe and Australia; all genotyping and genetic analyses were done at the same laboratory in the United Kingdom. We calculated polygenic risk scores for schizophrenia and bipolar disorder separately, and used linear regression to test whether polygenic scores influenced the endophenotypes. Results showed that higher polygenic scores for schizophrenia were associated with poorer performance on the block design task and explained 0.2% (p = 0.009) of the variance. Associations in the same direction were found for bipolar disorder scores, but this was not statistically significant at the 1% level (p = 0.02). The schizophrenia score explained 0.4% of variance in lateral ventricular volumes, the largest across all phenotypes examined, although this was not significant (p = 0.063). None of the remaining associations reached significance after correction for multiple testing (with alpha at 1%). These results indicate that common genetic variants associated with schizophrenia predict performance in spatial visualization, providing additional evidence that this measure is an endophenotype for the disorder with shared genetic risk variants. The use of endophenotypes such as this will help to characterize the effects of common genetic variation in psychosis
Neurotensin Receptor 1 Gene (NTSR1) Polymorphism Is Associated with Working Memory
BACKGROUND: Recent molecular genetics studies showed significant associations between dopamine-related genes (including genes for dopamine receptors, transporters, and degradation) and working memory, but little is known about the role of genes for dopamine modulation, such as those related to neurotensin (NT), in working memory. A recent animal study has suggested that NT antagonist administration impaired working memory in a learning task. The current study examined associations between NT genes and working memory among humans. METHODS: Four hundred and sixty healthy undergraduate students were assessed with a 2-back working memory paradigm. 5 SNPs in the NTSR1 gene were genotyped. 5 ANOVA tests were conducted to examine whether and how working memory differed by NTSR1 genotype, with each SNP variant as the independent variable and the average accuracy on the working memory task as the dependent variable. RESULTS: ANOVA results suggested that two SNPs in the NTSR1 gene (rs4334545 and rs6090453) were significantly associated with working memory. These results survived corrections for multiple comparisons. CONCLUSIONS: Our results demonstrated that NTSR1 SNP polymorphisms were significantly associated with variance in working memory performance among healthy adults. This result extended previous rodent studies showing that the NT deficiency impairs the working memory function. Future research should replicate our findings and extend to an examination of other dopamine modulators
Effectiveness of interventions in reducing pain and maintaining physical activity in children and adolescents with calcaneal apophysitis (Sever’s disease): a systematic review
Visuospatial working memory in children and adolescents with 22q11.2 deletion syndrome; an fMRI study
22q11.2 deletion syndrome (22q11DS) is a genetic disorder associated with a microdeletion of chromosome 22q11. In addition to high rates of neuropsychiatric disorders such as schizophrenia and attention deficit hyperactivity disorder, children with 22q11DS have a specific neuropsychological profile with particular deficits in visuospatial and working memory. However, the neurobiological substrate underlying these deficits is poorly understood. We investigated brain function during a visuospatial working memory (SWM) task in eight children with 22q11DS and 13 healthy controls, using fMRI. Both groups showed task-related activation in dorsolateral prefrontal cortex (DLPFC) and bilateral parietal association cortices. Controls activated parietal and occipital regions significantly more than those with 22q11DS but there was no significant between-group difference in DLPFC. In addition, while controls had a significant age-related increase in the activation of posterior brain regions and an age-related decrease in anterior regions, the 22q11DS children showed the opposite pattern. Genetically determined differences in the development of specific brain systems may underpin the cognitive deficits in 22q11DS, and may contribute to the later development of neuropsychiatric disorders
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