349 research outputs found

    Microstructure and properties of 308LSI steel obtained by deposition of metal wire

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    Shaped metal deposition (SMD) is a relatively new technology of additive manufacturing, which creates near-net shaped components by joining metallic materials by melting the area of a welding joint in high vacuum in the range from 10-3 to 10-6 mbar. In the present study, the main mechanical properties including micro-hardness and tensile properties were investigated. Single bead walls were deposited. Test pieces were machined from the deposited walls according to the National standard of Russia Federation for the mechanical tests. The tensile properties also showed dependence on the direction of the test carried out. All the examined tensile properties of the as deposited samples are close-matched properties of the as cast material

    Охрана редких, исчезающих видов животных. снежный барс (ИРБИС)

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    Данная статья посвящена вопросам охраны редких, исчезающих видов животных, в том числе снежных барсов. Рассмотрены факторы оказывающие пагубное воздействие на животный мир, также рассмотрено правовое регулирование проблемы снижения популяции снежного барса. Обозначены основные задачи для решения данной проблемы.This article is devoted to the protection of rare, endangered species of animals, including snow leopards. The factors that have a harmful effect on the animal world are considered, as well as the legal regulation of the snow leopard population decline problem. There are outlined main tasks for solving this problem

    Un enfoque fisiológico para los procesos oceánicos y los cambios glaciares-interglaciares del CO2 atmosférico

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    18 pages, 6 figures, 1 table[EN] One possible path for exploring the Earth’s far-from-equilibrium homeostasis is to assume that it results from the organisation of optimal pulsating systems, analogous to that in complex living beings. Under this premise it becomes natural to examine the Earth’s organisation using physiological-like variables. Here we identify some of these main variables for the ocean’s circulatory system: pump rate, stroke volume, carbon and nutrient arterial-venous differences, inorganic nutrients and carbon supply, and metabolic rate. The stroke volume is proportional to the water transported into the thermocline and deep oceans, and the arterial-venous differences occur between recently-upwelled deep waters and very productive high-latitudes waters, with atmospheric CO2 being an indicator of the arterial-venous inorganic carbon difference. The metabolic rate is the internal-energy flux (here expressed as flux of inorganic carbon in the upper ocean) required by the system’s machinery, i.e. community respiration. We propose that the pump rate is set externally by the annual cycle, at one beat per year per hemisphere, and that the autotrophic ocean adjusts its stroke volume and arterial-venous differences to modify the internal-energy demand, triggered by long-period astronomical insolation cycles (external-energy supply). With this perspective we may conceive that the Earth’s interglacial-glacial cycle responds to an internal organisation analogous to that occurring in living beings during an exercise-recovery cycle. We use an idealised double-state metabolic model of the upper ocean (with the inorganic carbon/nutrients supply specified through the overturning rate and the steady-state inorganic carbon/nutrients concentrations) to obtain the temporal evolution of its inorganic carbon concentration, which mimics the glacial-interglacial atmospheric CO2 pattern[ES] Un posible camino para el estudio de la homeóstasis fuera-de-equilibrio de la tierra es suponer que resulta de la organización de sistemas pulsátiles optimizados, análoga a aquélla en seres vivos complejos. Bajo esta premisa parece natural examinar la organización de la tierra utilizando variables de tipo fisiológico. Aquí identificamos algunas de las principales variables del sistema circulatorio oceánico: tasa de bombeo del corazón, volumen de latido, diferencias arteriovenosas de carbono y nutrientes, suministro de carbono y nutrientes inorgánicos, y tasa metabólica. El volumen de latido es proporcional al transporte de agua hacia la termoclina y océano profundo, y las diferencias arterio-venosas ocurren entre las aguas profundas recientemente afloradas y aquellas altamente productivas de altas latitudes, con el CO2 atmosférico siendo un indicador de la diferencia arterio-venosa de carbono inorgánico. La tasa metabólica es el flujo de energía interna (aquí expresado como flujo de carbono inorgánico en el océano superior) requerido por la maquinaria que sostiene el sistema, i.e. respiración total de la comunidad. Se propone que la tasa de latido está impuesta externamente, un latido por año por hemisferio, y que el océano autotrófico ajusta su volumen de latido y las diferencias arteriovenosas a cambios en la demanda de energía interna, inducido por ciclos de insolación astronómica de largo período (suministro de energía externa). Bajo esta perspectiva podemos concebir que el ciclo interglacial-glacial de la tierra responde a una organización interna análoga a la que ocurre en seres vivos durante un ciclo de ejercicio-recuperación. Se utiliza un modelo metabólico idealizado de dos estados para el océano superior (con el suministro de carbono/nutrientes inorgánicos especificado mediante la tasa de recirculación de aguas profundas y las concentraciones de carbono/nutrientes inorgánicos en estado estacionario) para obtener la evolución temporal de su concentración de carbono inorgánico, la cual mimetiza el patrón glacial-interglacial del CO2 atmosféricoThis work was supported by the Spanish government through the CANOA project (CTM2005-00444/MAR)Peer reviewe

    Density Profiles in Random Quantum Spin Chains

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    We consider random transverse-field Ising spin chains and study the magnetization and the energy-density profiles by numerically exact calculations in rather large finite systems (L128L\le 128). Using different boundary conditions (free, fixed and mixed) the numerical data collapse to scaling functions, which are very accurately described by simple analytic expressions. The average magnetization profiles satisfy the Fisher-de Gennes scaling conjecture and the corresponding scaling functions are indistinguishable from those predicted by conformal invariance.Comment: 4 pages RevTeX, 4 eps-figures include

    Методы повышения эффективности работы газотурбинных установок

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    Объект исследования: газотурбинная установка. Цель работы: аналитический обзор современных направлений повышения эффективности работы ГТУ, сравнительный расчет простой и регенеративной ГТУ при заданных равных условиях. Для достижения поставленной цели рассмотрены следующие задачи: проведение литературного обзора современных направлений повышения эффективности работы газотурбинных установок; сравнительный тепловой расчет простой и регенеративной ГТУ при заданных равных условиях; Определение сметной стоимости работ по монтажу регенератора; анализ вредныхThe object of the study: gas turbine plant. The purpose of the work: analytical review of modern directions of increasing the efficiency of GTP operation, comparative calculation of simple and regenerative GTP under given equal conditions. To achieve this goal, the following tasks are considered: conducting a literature review of modern technologies to increase the efficiency of gas turbine plants; comparative heat calculation of simple and regenerative gas turbine plant (efficiency, specific fuel consumption, heat rate) for given equal conditions; determination of the estimated cost of

    Grid-Adapted FUN3D Computations for the Second High Lift Prediction Workshop

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    Contributions of the unstructured Reynolds-averaged Navier-Stokes code FUN3D to the 2nd AIAA CFD High Lift Prediction Workshop are described, and detailed comparisons are made with experimental data. Using workshop-supplied grids, results for the clean wing configuration are compared with results from the structured code CFL3D Using the same turbulence model, both codes compare reasonably well in terms of total forces and moments, and the maximum lift is similarly over-predicted for both codes compared to experiment. By including more representative geometry features such as slat and flap brackets and slat pressure tube bundles, FUN3D captures the general effects of the Reynolds number variation, but under-predicts maximum lift on workshop-supplied grids in comparison with the experimental data, due to excessive separation. However, when output-based, off-body grid adaptation in FUN3D is employed, results improve considerably. In particular, when the geometry includes both brackets and the pressure tube bundles, grid adaptation results in a more accurate prediction of lift near stall in comparison with the wind-tunnel data. Furthermore, a rotation-corrected turbulence model shows improved pressure predictions on the outboard span when using adapted grids

    Incidence rates of progressive childhood encephalopathy in Oslo, Norway: a population based study

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    <p>Abstract</p> <p>Background</p> <p>Progressive encephalopathy (PE) in children is a heterogeneous group of diseases mainly composed of metabolic diseases, but it consists also of neurodegenerative disorders where neither metabolic nor other causes are found. We wanted to estimate the incidence rate and aetiology of PE, as well as the age of onset of the disease.</p> <p>Methods</p> <p>We included PE cases born between 1985 and 2003, living in Oslo, and registered the number presenting annually between 1985 and 2004. Person-years at risk between 0 and 15 years were based on the number of live births during the observation period which was divided into four 5-year intervals. We calculated incidence rates according to age at onset which was classified as neonatal (0–4 weeks), infantile (1–12 months), late infantile (1–5 years), and juvenile (6–12 years).</p> <p>Results</p> <p>We found 84 PE cases representing 28 diagnoses among 1,305,997 person years, giving an incidence rate of 6.43 per 100,000 person years. The age-specific incidence rates per 100,000 were: 79.89 (<1 year), 8.64 (1–2 years), 1.90 (2–5 years), and 0.65 (>5 years). 66% (55/84) of the cases were metabolic, 32% (27/54) were neurodegenerative, and 2% (2/84) had HIV encephalopathy. 71% (60/84) of the cases presented at < 1 year, 24% (20/84) were late infantile presentations, and 5% (4/84) were juvenile presentations. Neonatal onset was more common in the metabolic (46%) (25/55) compared to the neurodegenerative group (7%) (2/27). 20% (17/84) of all cases were classified as unspecified neurodegenerative disease.</p> <p>Conclusion</p> <p>The overall incidence rate of PE was 6.43 per 100,000 person years. There was a strong reduction in incidence rates with increasing age. Two-thirds of the cases were metabolic, of which almost half presented in the neonatal period.</p
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