Defect model for the mixed mobile ion effect revisited: an importance of deformation rates

The progress in understanding the behavior of glassy mixed ionic conductors within the concept of the defect model for the mixed mobile ion effect (V. Belostotsky, J. Non-Cryst. Solids 353 (2007) 1078) is reported. It is shown that in a mixed ionic conductor (e.g., mixed alkali glass) containing two or more types of dissimilar mobile ions of unequal size sufficient local strain arising from the size mismatch of a mobile ion entering a foreign site can not be, in principle, absorbed by the surrounding network-forming matrix without its damage. Primary site rearrangement occurs immediately, on the time scale close to that of the ion migration process, through the formation of intrinsic defects in the nearest glass network. Neither anelastic relaxation below glass transition temperature, Tg, nor viscoelastic or viscous behavior at or above Tg can be expected being observed in this case because the character of the stress relaxation in a wide temperature range is dictated above all by the deformation rates employed locally to the adjacent network-forming matrix. Since the ion migration occurs on the picosecond time scale, the primary rearrangement of the glass network adjacent to an ionic site occurs at rates orders of magnitude higher than those of the critical minimum values, so the matrix demonstrates brittle-elastic response to the arising strain even at temperatures well above Tg, which explains, among other things, why mixed alkali effect is observable in glass melts.Comment: 6 pages, 1 figure, 1 tabl

Proton Decay: Improving the sensitivity through nuclear dynamics?

The kinematics of the decay of a bound proton is governed by the proton spectral function. We evaluate this quantity in 16O using the information from nuclear physics experiments. It also includes a correlated part. The reliability of this evaluation is sufficient to open the possibility of correlated cuts in the missing mass and momentum variables in order to identify the decay events from the bound protons with a possible increase of the signal to noise ratio.Comment: 6 pages, 6 figures. CERN preprint: CERN-PH-TH/2010-036. To appear in Phys Rev

Systems Studies of Nuclear Energy Development in the USSR

It is one of the goals of the Energy program not only to do in-house research but to promote and pursue collaborative research and exchange of information with other institutions. One may view this interest as an attempt for a broader IIASA Energy program that encourages a wider vision of energy problems. Indeed, the number of groups that closely cooperate with the program is increasing; given our premise, reports of those groups may well be seen as an output of this broader Energy program. The present paper is a major contribution of the Institute of High Temperatures, Moscow, and the Siberian Power Institute, Irkutsk, USSR. It points to the systems implications of the development and future trends of the nuclear option against the background of the fuel resource situation in the USSR. Tangible contributions of this kind add to the understanding of actual systems problems. It is IIASA's intention to continue with such collaborative papers and to try to follow up on this line of activities

Численное моделирование снеговых нагрузок. Особенности и перспективы развития методики

Разработка методологии численного моделирования снеговой нагрузки сегодня является одной из важнейших задач строительной отрасли. Анализ мировых строительных норм и регламентов показывает, что ограниченного набора покрытий и схем распределения коэффициента формы μ недостаточно для обоснованного определения снеговой нагрузки, особенно на большепролётные и уникальные здания и сооружения. Применяющиеся на практике методы физического моделирования также обладают рядом существенных недостатков. В то же время современный уровень развития программных комплексов вычислительной аэрогидродинамики и большое число математических моделей снегонакопления позволяет моделировать снеговую нагрузку численно. Так, представленная в настоящей статье методика позволяет выполнять расчёт снеговой нагрузки на покрытиях зданий и сооружений в стационарной и нестационарной постановках. Нестационарная постановка даёт возможность наблюдать локальное изменение толщины снегового покрова во времени, однако является весьма ресурсоёмкой для расчёта снеговой нагрузки на покрытие в целом. Указанные недостатки решает моделирование в стационарной постановке, при котором основные уравнения модели  негонакопления решаются на «больших» временах. Полученные картины снегоотложений в сочетании с рекомендациями нормативных документов позволяют задать значение расчётного коэффициента формы μ для всех зон покрытия. На основе разработанной методики на базе НОЦ КМ им. А.Б. Золотова и Учебно-научно производственная лаборатория аэроакустических исследований строительных конструкций (УНПЛ ААИСК) НИУ МГСУ прорабатывается единая, комплексная расчётно-экспериментальная методология моделирования снеговых нагрузок, объединяющая преимущества физического и численного моделирования. Синтез двух подходов позволяет наиболее ёмко и разносторонне изучить процесс снегонакопления на покрытиях зданий и сооружений

Deviations from the Expected Relationship Between Serum FGF23 and Other Markers in Children with CKD: a cross-sectional study.

BACKGROUND: High levels of fibroblast growth factor-23 (FGF23) are associated with mortality. In chronic kidney disease (CKD), FGF23 levels rise as renal function declines. We analyzed the contribution of laboratory values to the variance of FGF23 levels in relationship to a curve of expected FGF23 levels for a given GFR. METHODS: Following approval by the research ethics boards, we measured FGF23, CysC eGFR, creatinine, urea, albumin, calcium, phosphate, vitamin D metabolites, PTH, alkaline phosphatase, CRP, and venous gases in 141 pediatric CKD patients (45, 37, 32, 13 and 14 CKD stages I, II, III, IV, and V, respectively). Data were expressed as median (25th, 75th percentile). RESULTS: FGF23 correlated significantly with CysC, CysC eGFR, PTH, 1.25 (OH) CONCLUSIONS: Our data emphasize the importance of phosphate and 1.25 (OH

Relativistic eikonal description of A(p,pN) reactions

The authors present a relativistic and cross-section factorized framework for computing quasielastic A(p,pN) observables at intermediate and high energies. The model is based on the eikonal approximation and can accomodate both optical potentials and the Glauber method for dealing with the initial- and final-state interactions (IFSI). At lower nucleon energies, the optical-potential philosophy is preferred, whereas at higher energies the Glauber method is more natural. This versatility in dealing with the IFSI allows one to describe A(p,pN) reactions in a wide energy range. Most results presented here use optical potentials as this approach is argued to be the optimum choice for the kinematics of the experiments considered in the present paper. The properties of the IFSI factor, a function wherein the entire effect of the IFSI is contained, are studied in detail. The predictions of the presented framework are compared with two kinematically different experiments. First, differential cross sections for quasielastic proton scattering at 1 GeV off 12C, 16O, and 40Ca target nuclei are computed and compared to data from PNPI. Second, the formalism is applied to the analysis of a 4He(p,2p) experiment at 250 MeV. The optical-potential calculations are found to be in good agreement with the data from both experiments, showing the reliability of the adopted model in a wide energy range.Comment: 34 pages, 14 figures, accepted for publication in Phys. Rev.

Secure SNMP

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 51-52).by Eugene B. Belostotsky.M.Eng

A cross-sectional study measuring vanadium and chromium levels in paediatric patients with CKD

Objectives Although many secondary effects of high levels of vanadium (V) and chromium (Cr) overlap with symptoms seen in paediatric patients with chronic kidney disease (CKD), their plasma V and Cr levels are understudied. Design Ancillary cross-sectional study to a prospective, longitudinal, randomised controlled trial. Setting Children\u27s Hospital of Western Ontario, London Health Sciences Centre, London, Ontario, Canada. Participants 36 children and adolescents 4-18 years of age with CKD. Interventions 1-6 trace element measurements per patient. Cystatin C (CysC) estimated glomerular filtration rate (eGFR) was calculated using the Filler formula. Plasma V and Cr levels were measured using high-resolution sector field inductively coupled mass spectrometry. Anthropomorphic data and blood parameters were collected from our electronic chart programme. Water Cr and V data were obtained from the Ontario Water (Stream) Quality Monitoring Network. Primary and secondary outcome measures Primary outcomes: Plasma Cr and V. Secondary outcomes: Age, season, CysC, CysC eGFR, and Cr and V levels in environmental water. Results The median (IQR) eGFR was 51 mL/min/1.73 m 2 (35, 75). The median V level was 0.12 μg/L (0.09, 0.18), which was significantly greater than the 97.5th percentile of the reference interval of 0.088 μg/L; 32 patients had at least one set of V levels above the published reference interval. The median Cr level was 0.43 μg/L (0.36, 0.54), which was also significantly greater than the established reference interval; 34 had at least one set of Cr levels above the published reference interval. V and Cr levels were moderately correlated. Only some patients had high environmental exposure. Conclusions Our study suggests that paediatric patients with CKD have elevated plasma levels of V and Cr. This may be the result of both environmental exposure and a low eGFR. It may be necessary to monitor V and Cr levels in patients with an eGFR \u3c30 mL/min/1.73 m2