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МАТЕМАТИКА И ЕСТЕСТВЕННЫЕ НАУКИ


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51МАТЕМАТИКА (2481)

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53ФИЗИКА (2347)

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59ЗООЛОГИЯ (306)

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FRAGILITY, TETRAGONALITY, CHANGE THE MORPHOLOGY MARTENSITE, DESTABILIZATION OF AUSTENITE WITH CARBON IF IT MORE THAN ~ 0,5 %, AS A RESULT OF THE PRESENCE OF A PERCEIVED INTERMEDIATE PHASE ~ FE42C

Автор: Shakhnazarov

Using analogies, descriptions, illustrations and quotations from the works of famous metallurgical scientists, an attempt was done to link tetragonality, fragility, changes in the morphology of the martensite, destabilization of austenite carbon when % С > (~ 0,5 %) with intermediate phase ~ Fe42С (~ 0,5 % C). If % C > 0,5: martensite begins to change the morphology from dislocation to twin structure and become catastrophically fragile as well as becomes tetragonal without clasuse on smoothback during quench cooling; ferrite loses its ability to be widmanstatten and strengthen as a result of natural aging after subcritical quenching; the yield strength of ferrite-cementine mixture, regardless form of cementite, even begins to fall; the interval of martensite transformation starts to decrease, etc.

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FINITE ELEMENT MODELLING OF PIPELINE WITH VOLUMETRIC DEFECT (КОНЕЧНО-ЭЛЕМЕНТНОЕ МОДЕЛИРОВАНИЕ ТРУБОПРОВОДА С ОБЪЁМНЫМ ДЕФЕКТОМ)

Автор: Lyapin

Рассмотрена нелинейная задача о моделировании поврежденного трубопровода под действием внутреннего давления. При помощи метода конечных элементов построены поля смещений, пластических деформаций и напряжений в среде. Расчет проведен с использованием модели пластичности для материала трубопровода. Проанализирован уровень напряжений в различных областях конструкции. В качестве материала использован наиболее распространенный сплав, применяемый при создании нефтяных трубопроводов. Изучено влияние геометрии дефекта на напряженно-деформированное состояние структуры. Получены результаты, позволяющие сократить расходы на создание тестовых образцов.

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FEASIBILITY STUDY — VITAMIN D LOADING DETERMINATION BY FTIR-ATR

Purpose: The aim of the present study was to develop a simple and accurate way to measure vitamin D levels. Vitamin D nowadays is measured by a variety of methods which their common drawbacks are expensive equipment and the need for high trained technical staff. In this research we measured vitamin D levels by means of Fourier transform infra red method in conjugation with the evanescent wave spectroscopy technique, in order to develop a simpler vitamin D measurement method. Methods: Blood samples were collected from patients with vitamin D deficiency at five intervals before and up to 16 days after they took a dose of 200,000 IU vitamin D3. Samples were measured by the conventional bio-chemical method and by the evanescent wave spectroscopy means. Results: Correlation was found between the vitamin D levels measured by the traditional method and by the evanescent wave spectroscopy technique. The absorption lines occurred prominently in the IR spectral regions of the Amide I (≈1650 cm−1),Amide II (≈1530 cm−1) and the (≈3400 cm−1) absorption band which is attributed to the hydroxyl group indicated by the O-H stretch. In addition, the examination of the blood samples using the evanescent wave spectroscopy with clustering techniques facilitated the discrimination between vitamin D deficiency and normal vitamin D levels. Practical relevance: This study demonstrates the potential of using the Fourier transform infra red method in conjugation with the evanescent wave spectroscopy techniquecoupled with multivariate analysis as a nonexpensive, rapid and accurate alternative to the routine methodologies.

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First Yaroslavl Summer School on Discrete and Computational Geometry. July - August, 2012

ЯрГУ

The International Delaunay Laboratory of Discrete and Computational Geometry introduces a new books series: the Delaunay Library. We open the series with the First Yaroslavl Summer School on Discrete and Computational Geometry, which contains lecture notes accompanying the short courses delivered in July and August of 2012. We hope this volume will be useful to all students and post graduates interested in the current state-of-the-art in this field. Funded by Russian Government Grant 220 / Contract 11.G34.31.0053/

Предпросмотр: First Yaroslavl Summer School on Discrete and Computational Geometry. July August, 2012. Lecture Notes.pdf (0,3 Мб)
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Floresiensis homo?

Автор: Комаров
ПРОМЕДИА: М.

При раскопках был найден древне-индонезийский карлик, который имеет сходства с особым видом человека.