Radiation Heating of Primary Collimators at Ramping

A time-dependent temperature map is derived for the primary jaw of the momentum collimation system during the high transient loss period which is to occur at the beginning of the ramp of acceleration. An adequate margin factor is obtained for a loss of 5% of the nominal stored beam and for the nominal parabolic ramping curve

Magnetic phase transitions in Ta/CoFeB/MgO multilayers

We study thin films and magnetic tunnel junction nanopillars based on Ta/Co$_{20}$Fe$_{60}$B$_{20}$/MgO multilayers by electrical transport and magnetometry measurements. These measurements suggest that an ultrathin magnetic oxide layer forms at the Co$_{20}$Fe$_{60}$B$_{20}$/MgO interface. At approximately 160 K, the oxide undergoes a phase transition from an insulating antiferromagnet at low temperatures to a conductive weak ferromagnet at high temperatures. This interfacial magnetic oxide is expected to have significant impact on the magnetic properties of CoFeB-based multilayers used in spin torque memories

Formation of "Lightnings" in a Neutron Star Magnetosphere and the Nature of RRATs

The connection between the radio emission from "lightnings" produced by the absorption of high-energy photons from the cosmic gamma-ray background in a neutron star magnetosphere and radio bursts from rotating radio transients (RRATs) is investigated. The lightning length reaches 1000 km; the lightning radius is 100 m and is comparable to the polar cap radius. If a closed magnetosphere is filled with a dense plasma, then lightnings are efficiently formed only in the region of open magnetic field lines. For the radio emission from a separate lightning to be observed, the polar cap of the neutron star must be directed toward the observer and, at the same time, the lightning must be formed. The maximum burst rate is related to the time of the plasma outflow from the polar cap region. The typical interval between two consecutive bursts is ~100 s. The width of a single radio burst can be determined both by the width of the emission cone formed by the lightning emitting regions at some height above the neutron star surface and by a finite lightning lifetime. The width of the phase distribution for radio bursts from RRATs, along with the integrated pulse width, is determined by the width of the bundle of open magnetic field lines at the formation height of the radio emission. The results obtained are consistent with the currently available data and are indicative of a close connection between RRATs, intermittent pulsars, and extreme nullers.Comment: 24 pages, no figures, references update

The impact of snow cover on nutrients dynamics in Western Siberia territories

International audienc

Технологические и реологические основы формования макаронных изделий в узлах прессования с предварительным двухступенчатым уплотнением, пластификацией и разогревом теста

One of efficient directions for pasta press designs modernization is installation of special conical-andcylindrical inserts in the pre-matrix space and matrix wells in front of the dies having, like Venturi tubes, narrowing zones (convergent), expansion (divergent) and a cylindrical path located between them. However, rheological aspects of such method of forming tool modernizing in relation to pasta presses have not been studied, recommendations for structural elements calculation and design have not been developed. All this is a significant obstacle for using the method in engineering and industrial practice. The research purpose is to develop rheological models the pasta dough flow in the conical-cylindrical channels of convergent-divergent inserts and to evaluate with their help the impact of structural dimensions and rheological properties on resistance to pasta dough flow. Pasta dough was considered as a rheological complex nonlinearly viscous plastic material. In technical calculations contribution of shear strength was neglected and a rheological analysis was performed using the Oswald-de-Ville power law equation. Analytical dependences obtained make it possible to calculate the pressure drops in the convergent-divergent insert and its elements. Numerical modeling was performed and calculated data were obtained regarding the impact of dimensions of structural elements of the insert and rheological parameters of pasta dough on its resistance to viscous flow. The results obtained can form the basis of engineering and technological calculations in design of convergent-divergent inserts for laboratory and industrial pasta presses.Одним из эффективных направлений модернизации конструкций макаронных прессов является установка в предматричном пространстве и колодцах матрицы перед фильерами специальных коническо-цилиндрических вставок, имеющих, подобно трубкам Вентури, зоны сужения (конфузор), расширения (диффузор) и расположенный между ними цилиндрический поясок. Однако реологические аспекты такого метода модернизации формообразующей оснастки применительно к макаронным прессам не изучены, рекомендации по расчету и проектированию конструктивных элементов не разработаны. Все это является существенным препятствием для использования метода в инженерной и производственной практике. Цель работы – разработка реологических моделей течения макаронного теста в коническо-цилиндрических каналах конфузорно-диффузорныхвставок и оценка с их помощью влияния конструктивных размеров и показателей реологических свойств на сопротивление течению макаронного теста. Макаронное тесто рассматривали как реологически сложный, нелинейно вязко-пластичный материал. При технических расчетах вкладом сдвиговой прочности пренебрегали и осуществляли реологический анализ с использованием степенного реологического уравнения Освальда-де-Вила. Получены аналитические зависимости, позволяющие производить расчет перепадов давления в конфузорно-диффузорной вставке и ее элементах. Произведено численное моделирование и получены расчетные данные по влиянию размеров конструктивных элементов вставки и расхода макаронного теста через вставку на сопротивление его вязкому течению. Полученные результаты могут составить основу инженерно-технологических расчетов при проектировании конфузорно-диффузорных вставок для лабораторных и промышленных макаронных прессов

Реологическое моделирование процессов течения макаронного теста в каналах конфузорно-диффузорных вставок формующих матриц

One of efficient directions for pasta press designs modernization is installation of special conical-and-cylindrical inserts in the matrix wells in front of the dies having, like Venturi tubes, narrowing zones (convergent), expansion (divergent) and a cylindrical path located between them. However, rheological aspects of such method of forming tool modernizing in relation to pasta presses have not been studied, recommendations for structural elements calculation and design have not been developed. All this is a significant obstacle for using the method in engineering and industrial practice. The research purpose is to develop rheological models the pasta dough flow in the conical-cylindrical channels of convergent-divergent inserts and to evaluate with their help the impact of structural dimensions and rheological properties on resistance to pasta dough flow. Pasta dough was considered as a rheological complex nonlinearly viscous plastic material. In technical calculations contribution of shear strength was neglected and a rheological analysis was performed using the Oswald-de-Vila power law equation. Analytical dependences obtained make it possible to calculate the pressure drops in the convergent-divergent insert and its elements. Numerical modeling was performed and calculated data were obtained regarding the impact of dimensions of structural elements of the insert and rheological parameters of pasta dough on its resistance to viscous flow. The results obtained can form the basis of engineering and technological calculations in design of convergent-divergent inserts for laboratory and industrial matrices of pasta presses.Одним из эффективных направлений модернизации конструкций макаронных прессов является установка в колодцах матрицы перед фильерами специальных коническо- цилиндрических вставок, имеющих, подобно трубкам Вентури, зоны сужения (конфузор), расширения (диффузор) и расположенный между ними цилиндрический поясок. Однако реологические аспекты такого метода модернизации формообразующей оснастки применительно к макаронным прессам не изучены, рекомендации по расчету и проектированию конструктивных элементов не разработаны. Все это является существенным препятствием для использования метода в инженерной и производственной практике. Цель работы – разработка реологических моделей течения макаронного теста в коническо-цилиндрических каналах конфузорно-диффузорных вставок и оценка с их помощью влияния конструктивных размеров и показателей реологических свойств на сопротивление течению макаронного теста. Макаронное тесто рассматривали как реологически сложный, нелинейно вязко-пластичный материал. При технических расчетах вкладом сдвиговой прочности пренебрегали и осуществляли реологический анализ с использованием степенного реологического уравнения Освальда–де–Вила. Получены аналитические зависимости, позволяющие производить расчет перепадов давления в конфузорно-диффузорной вставке и ее элементах. Произведено численное моделирование и получены расчетные данные по влиянию размеров конструктивных элементов вставки и расхода макаронного теста через вставку на сопротивление его вязкому течению. Полученные результаты могут составить основу инженерно технологических расчетов при проектировании конфузорно-диффузорных вставок для лабораторных и промышленных матриц макаронных прессов

Prevalence of diabetes mellitus in patients with acromegaly

Early carbohydrate metabolism disorders (ECMDs) and diabetes mellitus (DM) are frequently associated with acromegaly. We aimed to assess the prevalence of ECMDs in patients with acromegaly and to compare the results with those in adults without acromegaly using two population-based epidemiologic surveys. We evaluated 97 patients with acromegaly in several phases of their disease (mean age, 56 years and estimated duration of acromegaly, 12.5 years). An oral glucose tolerance test was done in those not yet diagnosed with DM to reveal asymptomatic DM or ECMDs (impaired glucose tolerance+impaired fasting glucose). Comparisons were made between patients with acromegaly and participants from the general adult population (n=435) and an adult population with multiple type 2 diabetes risk factors (n=314), matched for gender, age and BMI. DM was diagnosed in 51 patients with acromegaly (52.5%) and 14.3% of the general population (P<0.001). The prevalence of ECMDs was also higher in patients with acromegaly than in the general population and in the high-risk group; only 22% of patients with acromegaly were normoglycaemic. The prevalence of newly diagnosed ECMDs or DM was 1.3-1.5 times higher in patients with acromegaly compared with the high-risk group. Patients with acromegaly having ECMDs or DM were older, more obese and had longer disease duration and higher IGF1 levels (Z-score). Logistic regression showed that the severity of glucose derangement was predicted by age, BMI and IGF1 levels. In patients with acromegaly, the prevalence of DM and ECMDs considerably exceeds that of the general population and of a high-risk group, and development of DM depends on age, BMI and IGF1 levels

Magnetic Field Generation in Stars

Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe