Thermoanalytical characterization of several Antarctic meteorites

Thermodynamic data for several meteorites from Antarctica (5 achondrites, 2 chondrites, and 1 iron) were derived. The thermochemical response to heating in air was examined. The effects of oxidation processes can often be better identified by comparing the differential thermal analysis (DTA)-curves for heating in air with those obtained for heating in an oxidation-suppressed argon atmosphere. The thermoanalytical method can be helpful in determining the degree of weathering of meteoritic material

Analysis of ecological intensity of metallurgical production

Ferrous metallurgy is inherently a highly intensive field in terms of energy and raw materials. The impacts of high energy intensity are enormous: the necessary production of larger amount of energy related to high emissions of pollutants and greenhouse gases, associated with increasing negative impacts on the state of the environment and the health of inhabitants. The article suggests the possibility of using the method of structural analysis to calculate direct and complex ecological intensity and to use it as a basis to determine the ecological intensity of the individual metallurgical technologies. The processing of ecological structural model can significantly contribute to the identification of ecologically intensive final products and can improve the decision-making process in this area

Academic Resilience: A Retrospective Study of Adults With Learning Difficulties

This article reports qualitative analyses of two sets of retrospective interviews with adults with learning difficulties. The purpose of the study was to examine the high school experiences of these adults from a holistic perspective to understand possible factors that contributed to one group staying in school and the other group leaving school early. One set of interviews was conducted with adults who had returned to complete high school at an adult learning center (the late successful group). The second set of interviews was conducted with the early successful group, adults who had completed high school during adolescence. Interview questions focused on interests, friends, and general aspects of the high school experience. Analyses yielded three themes: intrapersonal support, interpersonal support, and institutional support. These data suggest that schools might act in a number of ways to counter the high rate of early leaving by adolescents with learning disabilities, including building strong teacher-student relationships, using students' interests to develop curricula and structured activities, and fostering a sense of purpose.Cet article expose deux analyses qualitatives de deux séries d'entrevues rétrospectives auprès d'adultes présentant des difficultés d'apprentissage. Le but de l'étude consistait à examiner, dans une perspective holistique, les expériences qu'avaient vécues ces adultes quand ils étaient au secondaire, pour ensuite déterminer si des facteurs avaient influencé le fait que certaines personnes étaient restées à l'école alors que d'autres avaient décroché. Une série d'entrevues a été effectuée auprès d'adultes qui avaient repris leurs études secondaires dans un institut d'apprentissage pour adultes (le groupe de diplômés tardifs). La deuxième série d'entrevues a eu lieu auprès d'adultes ayant terminé l'école secondaire alors qu'ils étaient adolescents dégroupe de diplômés précoces). Les questions d'entrevues portaient sur les intérêts, les amis et les aspects généraux de leur expérience à l'école secondaire. Trois thèmes sont ressortis des analyses: l'appui intrapersonnel, l'appui interpersonnel et l'appui institutionnel. Ces données donnent à penser que les écoles pourraient intervenir de diverses façons pour contrer le taux élevé de décrochage chez les adolescents ayant des difficultés d'apprentissage. Parmi ces stratégies notons la création de rapports solides entre les enseignants et les élèves, le développement de programmes d'études et d'activités structurées basés sur les intérêts des élèves et le fait de favoriser des buts bien précis

Anti-dumping proceedings in metallurgical brand

Dumping can be generally defined as an unfair trade practice, in which a manufacturer sells identical products or very similar products in the foreign market at price that is lower than their normal value in the domestic market. Metallurgical materials and products are among those products which the anti-dumping duty is often imposed on. The market with metallurgical products and the methodology used for calculating the dumping range have certain specific features related to the decisions on possible dumping and its amount, as presented in the article

Deuteron spin-lattice relaxation in the presence of an activation energy distribution: Application to methanols in zeolite NaX

A new method is introduced for analyzing deuteron spin-lattice relaxation in molecular systems with a broad distribution of activation energies and correlation times. In such samples the magnetization recovery is strongly non-exponential but can be fitted quite accurately by three exponentials. The considered system may consist of molecular groups with different mobility. For each group a Gaussian distribution of the activation energy is introduced. By assuming for every subsystem three parameters: the mean activation energy E-0, the distribution width sigma and the pre-exponential factor tau(0) for the Arrhenius equation defining the correlation time, the relaxation rate is calculated for every part of the distribution. Experiment-based limiting values allow the grouping of the rates into three classes. For each class the relaxation rate and weight is calculated and compared with experiment. The parameters E-0, sigma and tau(0) are determined iteratively by repeating the whole cycle many times. The temperature dependence of the deuteron relaxation was observed in three samples containing CD3OH (200% and 100% loading) and CD3OD (200%) in NaX zeolite and analyzed by the described method between 20 K and 170 K. The obtained parameters, equal for all the three samples, characterize the methyl and hydroxyl mobilities of the methanol molecules at two different locations. (C) 2012 Elsevier Inc. All rights reserved

Translational and rotational mobility of methanol-d(4) molecules in NaX and NaY zeolite cages: A deuteron NMR investigation

Nuclear magnetic resonance (NMR) provides means to investigate molecular dynamics at every state of matter. Features characteristic for the gas phase, liquid-like layers and immobilized methanol-d(4) molecules in NaX and NaY zeolites were observed in the temperature range from 300 K down to 20 K. The NMR spectra at low temperature are consistent with the model in which molecules are bonded at two positions: horizontal (methanol oxygen bonded to sodium cation) and vertical (hydrogen bonding of hydroxyl deuteron to zeolite framework oxygen). Narrow lines were observed at high temperature indicating an isotropic reorientation of a fraction of molecules. Deuteron spin-lattice relaxation gives evidence for the formation of trimers, based on observation of different relaxation rates for methyl and hydroxyl deuterons undergoing isotropic reorientation. Internal rotation of methyl groups and fixed positions of hydrogen bonded hydroxyl deuterons in methyl trimers provide relaxation rates observed experimentally. A change in the slope of the temperature dependence of both relaxation rates indicates a transition from the relaxation dominated by translational motion to prevailing contribution of reorientation. Trimers undergoing isotropic reorientation disintegrate and separate molecules become localized on adsorption centers at 166.7 K and 153.8 K for NaX and NaY, respectively, as indicated by extreme broadening of deuteron NMR spectra. Molecules at vertical position remain localized up to high temperatures. That indicates the dominating role of the hydrogen bonding. Mobility of single molecules was observed for lower loading (86 molecules/uc) in NaX. A direct transition from translation to localization was observed at 190 K. (C) 2012 Elsevier Inc. All rights reserved

Metabolic improvements following Roux-en-Y surgery assessed by solid meal test in subjects with short duration type 2 diabetes

BACKGROUND: Glucose homeostasis improves within days following Roux-en-Y gastric bypass (RYGB) surgery. The dynamic metabolic response to caloric intake following RYGB has been assessed using liquid mixed meal tolerance tests (MMTT). Few studies have evaluated the glycemic and hormonal response to a solid mixed meal in subjects with diabetes prior to, and within the first month following RYGB. METHODS: Seventeen women with type 2 diabetes of less than 5 years duration participated. Fasting measures of glucose homeostasis, lipids and gut hormones were obtained pre- and post-surgery. MMTT utilizing a solid 4 oz chocolate pudding performed pre-, 2 and 4 weeks post-surgery. Metabolic response to 4 and 2 oz MMTT assessed in five diabetic subjects not undergoing surgery. RESULTS: Significant reductions in fasting glucose and insulin at 3 days, and in fasting betatrophin, triglycerides and total cholesterol at 2 weeks post-surgery. Hepatic insulin clearance was greater at 3 days post-surgery. Subjects exhibited less hunger and greater feelings of fullness and satisfaction during the MMTT while consuming 52.9 ± 6.5% and 51.0 ± 6.5% of the meal at 2 and 4 weeks post-surgery respectively. At 2 weeks post-surgery, glucose and insulin response to MMTT were improved, with greater GLP-1 and PYY secretion. Improved response to solid MMTT not replicated by consumption of smaller pudding volume in diabetic non-surgical subjects. CONCLUSIONS: With a test meal of size and composition representative of the routine diet of post-RYGB subjects, improved glycemic and gut hormone responses occur which cannot be replicated by reducing the size of the MMTT in diabetic subjects not undergoing surgery