Peaceman Well Block Problem For Time-Dependent Flows of Compressible Fluid

We consider sewing machinery between finite difference and analytical solutions defined at different scales: far away and near the source of the perturbation of the flow. One of the essences of the approach is that coarse problem and boundary value problem in the proxy of the source model two different flows. In his remarkable paper Peaceman propose a framework how to deal with solutions defined on different scale for linear \textbf{time independent} problem by introducing famous, Peaceman well block radius. In this article we consider novel problem how to solve this issue for transient flow generated by compressiblity of the fluid. We are proposing method to glue solution via total fluxes, which is predefined on coarse grid and changes in the pressure, due to compressibility, in the block containing production(injection) well. It is important to mention that the coarse solution "does not see" boundary. From industrial point of view our report provide mathematical tool for analytical interpretation of simulated data for compressible fluid flow around a well in a porous medium. It can be considered as a mathematical "shirt" on famous Peaceman well-block radius formula for linear (Darcy) transient flow but can be applied in much more general scenario. In the article we use Einstein approach to derive Material Balance equation, a key instrument to define $R_0$. We will enlarge Einstein approach for three regimes of the Darcy and non-Darcy flows for compressible fluid(time dependent): $\textbf{I}. Stationary ; \textbf{II}. Pseudo \ Stationary(PSS) ; \textbf{III}. Boundary \ Dominated(BD).

High-Frequency Capacitor with Working Substance "Insulator–Undoped Silicon–Insulator"

The study of the parameters of capacitors with various working substances is of interest for the design and creation of electronic elements, in particular for the development of high-frequency phase-shifting circuits. The purpose of the work is to calculate the high-frequency capacitance of a capacitor with the working substance insulator undoped silicon insulator at different applied to the capacitor direct current (DC) voltages, measuring signal frequencies and temperatures. A model of such the capacitor is proposed, in which 30 µm thick layer of undoped (intrinsic) crystalline silicon (i-Si) is separated from each of the capacitor electrodes by 1 µm thick insulator layer (silicon dioxide). The dependences of the capacitor capacitance on the DC electrical voltage U on metal electrodes at zero frequency and at the measuring signal frequency of 1 MHz at absolute temperatures T = 300 and 400 K are calculated. It is shown that the real part of the capacitor capacitance increases monotonically, while the imaginary part is negative and non-monotonically depends on U at the temperature T = 300 K. An increase in the real part of the capacitor capacitance up to the geometric capacitance of oxide layers with increasing temperature is due to a decrease in the electrical resistance of i-Si layer. As a result, with an increase in temperature up to 400 K, the real and imaginary parts of the capacitance take constant values independent of U. The capacitance of i-Si layer with an increase in both temperature T and voltage U is shunted by the electrical conductivity of this layer. The phase shift is determined for a sinusoidal electrical signal with a frequency of 0.3, 1, 10, 30, 100, and 300 MHz applied to the capacitor at temperatures 300 and 400 K

Высокочастотный конденсатор с рабочим веществом «изолятор нелегированный кремний изолятор»

The study of the parameters of capacitors with various working substances is of interest for the design and creation of electronic elements, in particular for the development of high-frequency phase-shifting circuits.The purpose of the work is to calculate the high-frequency capacitance of a capacitor with the working substance "insulator-undoped silicon-insulator" at different applied to the capacitor direct current (DC) voltages, measuring signal frequencies and temperatures.A model of such the capacitor is proposed, in which 30 µm thick layer of undoped (intrinsic) crystalline silicon (i-Si) is separated from each of the capacitor electrodes by 1 µm thick insulator layer (silicon dioxide).The dependences of the capacitor capacitance on the DC electrical voltage U on metal electrodes at zero frequency and at the measuring signal frequency of 1 MHz at absolute temperatures T = 300 and 400 K are calculated. It is shown that the real part of the capacitor capacitance increases monotonically, while the imaginary part is negative and non-monotonically depends on U at the temperature T = 300 K. An increase in the real part of the capacitor capacitance up to the geometric capacitance of oxide layers with increasing temperature is due to a decrease in the electrical resistance of i-Si layer. As a result, with an increase in temperature up to 400 K, the real and imaginary parts of the capacitance take constant values independent of U. The capacitance of i-Si layer with an increase in both temperature T and voltage U is shunted by the electrical conductivity of this layer. The phase shift is determined for a sinusoidal electrical signal with a frequency of 0.3, 1, 10, 30, 100, and 300 MHz applied to the capacitor at temperatures 300 and 400 K.Исследование параметров электрических конденсаторов с различными рабочими веществами представляет интерес для проектирования и создания элементов электроники, в частности для разработки высокочастотных фазосдвигающих цепей.Цель работы рассчитать высокочастотную электрическую емкость конденсатора с рабочим веществом «изолятор нелегированный кремний изолятор» при различных подаваемых на конденсатор постоянных напряжениях, частотах измерительного сигнала и температурах.Предложена модель такого конденсатора, в которой слой нелегированного (собственного) кристаллического кремния (i-Si) толщиной 30 мкм отделен от каждого из электродов конденсатора слоем изолятора (диоксида кремния) толщиной 1 мкм.Рассчитаны зависимости емкости конденсатора от постоянного электрического напряжения U на металлических электродах на нулевой частоте и на частоте измерительного сигнала 1 МГц при абсолютных температурах T = 300 и 400 К. Показано, что действительная часть емкости конденсатора монотонно возрастает, а мнимая часть отрицательна и немонотонно зависит от U при температуре T = 300 К. Увеличение действительной части емкости конденсатора до геометрической емкости оксидных слоев при увеличении температуры обусловлено уменьшением электрического сопротивления слоя i-Si. Вследствие этого с увеличением температуры до 400 К действительная и мнимая части емкости принимают постоянные значения, независящие от U. Емкость слоя i-Si при увеличении как температуры T, так и напряжения U шунтируется электрической проводимостью этого слоя. Определен сдвиг фаз для синусоидального электрического сигнала с частотой 0,3; 1; 10; 30; 100 и 300 МГц, подаваемого на конденсатор при температурах 300 и 400 К

Схема элемента Пельтье на полупроводниках с прыжковым переносом электронов по дефектам

The study of thermoelectric properties of crystalline semiconductors with structural defects is of practical interest in the development of radiation-resistant Peltier elements. In this case, the spectrum of energy levels of hydrogen-like impurities and intrinsic point defects in the band gap (energy gap) of crystal plays an important role.The purpose of this work is to analyze the features of the single-electron band model of semiconductors with hopping electron migration both via atoms of hydrogen-like impurities and via their own point triplecharged intrinsic defects in the c- and v-bands, as well as to search for the possibility of their use in the Peltier element in the temperature range, when the transitions of electrons and holes from impurity atoms and/or intrinsic defects to the c- and v-bands can be neglected.For Peltier elements with electron hopping migration we propose: (i) an h-diode containing |d1)and |d2)-regions with hydrogen-like donors of two types in the charge states (0) and (+1) and compensating them hydrogen-like acceptors in the charge state (−1); (ii) a homogeneous semiconductor containing intrinsic t-defects in the charge states (−1, 0, +1), as well as ions of donors and acceptors to control the distribution of t-defects over the charge states. The band diagrams of the proposed Peltier elements in equilibrium and upon excitation of a stationary hopping electric current are analyzed.A model of the h-diode containing hydrogen-like donors of two types |d1) and |d2) with hopping migration of electrons between them for 50 % compensation by acceptors is considered. It is shown that in the case of the reverse (forward) electrical bias of the diode, the cooling (heating) of the region of the electric double layer between |d1)and |d2)-regions is possible.A Peltier element based on a semiconductor with point t-defects is considered. It is assumed that the temperature and the concentration of ions of hydrogen-like acceptors and donors are to assure all t-defects to be in the charge state (0). It is shown that in such an element it is possible to cool down the metal-semiconductor contact under a negative electric potential and to heat up the opposite contact under a positive potential.Исследование термоэлектрических свойств кристаллических полупроводников с дефектами структуры представляет практический интерес при создании радиационно-стойких элементов Пельтье. При этом важную роль играет спектр уровней энергии водородоподобных примесей и собственных точечных дефектов в энергетической щели (запрещённой зоне) кристалла.Цель работы анализ особенностей одноэлектронной зонной модели полупроводников с прыжковой миграцией электронов как по атомам водородоподобных примесей, так и по собственным точечным трёхзарядным дефектам, а также поиск возможности их использования в элементе Пельтье в области температур, когда переходами электронов и дырок с атомов примесей и/или собственных дефектов в cи v-зоны можно пренебречь.В качестве элементов Пельтье с прыжковой миграцией электронов предложены: 1) h-диод, содержащий |d1)и |d2)-области с водородоподобными донорами двух сортов в зарядовых состояниях(0) и (+1) и компенсирующие их водородоподобные акцепторы в зарядовом состоянии (−1); 2) однородный полупроводник, содержащий собственные t-дефекты в зарядовых состояниях (−1, 0, +1), а также ионы доноров и акцепторов для управления распределением t-дефектов по зарядовых состояниям. Проанализированы зонные диаграммы предлагаемых элементов Пельтье в равновесии  и при возбуждении стационарного прыжкового электрического тока.Рассмотрена модель h-диода, содержащего водородоподобные доноры двух сортов |d1) и |d2) с прыжковой миграцией между ними электронов при компенсации их на 50 % акцепторами. Показано, что при обратном (прямом) электрическом смещении диода возможно охлаждение (нагревание) области двойного электрического слоя между |d1)и |d2)-областями.Рассмотрен элемент Пельтье на основе полупроводника с точечными t-дефектами. Принималось, что температура, а также концентрации ионов водородоподобных акцепторов и доноров таковы, что практически все t-дефекты находятся в зарядовом состоянии (0). Показано, что в таком элементе возможно охлаждение контакта металл-полупроводник, находящегося под отрицательным электрическим потенциалом, и нагревание противоположного контакта, под положительным потенциалом

Investigation of the effect of copper addition on physical and mechanical properties of TiNi-Cu porous alloy

This work is devoted to the physical and mechanical properties of porous alloys based on TiNi alloyed with different amounts of Cu additive. We show that by doping a porous TiNi alloy with copper instead of nickel, it is possible to obtain characteristics acceptable for use in implantology and superior to those of known porous TiNi alloys. Cu addition in the range from 1 to 10 at.% is shown to optimize the properties of tested alloys. There is a decrease in the minimal martensitic transformation stress τminMs from 37 to 17 MPa when compared to initial unalloyed TiNi. Alloys with 3 and 6 at.% of Cu are found to be optimal for use in medical practice. Along with a wide temperature range of reversible deformations that cover the range of operating temperatures (273–313 K), such alloys demonstrate their martensitic transformation stress values below 28 MPs. This permits to model implantable structures of complex configuration from such materials under a certain temperature regime

Production of two-dimensional porous TiNi-based powder material by diffusion sintering and electron-beam processing

The paper addresses the study of the surface condition of two-dimensional porous TiNi-based powder materials produced by diffusion sintering and electron-beam processing. Methods of production of two-dimensional TiNibased materials to be used for the purposes of non-destructive testing have been proven. The surface condition of the produced materials is described by scanning electron microscopy and interference profilometry

Development and validation of a quantitative HPLC/MS/MS method for the determination of piperacillin in blood plasma

Reduced mortality in patients with sepsis taking piperacillin is possible when they receive a long-term infusion, which improves the effect of antimicrobials. However, such piperacillin therapy requires therapeutic drug monitoring, the use of the latest analytical equipment and developed methods for the quantitative determination of piperacilli

Numerical Modeling of the Dispersed Particles Distribution and FIxation during the Centrifugal Casting with Vertical and Horizontal Rotation Axes

Numerical modeling of the dispersed particles distribution in the production billets has been carried out. Centrifugal casting machine with vertical and horizontal rotation axes has been used. Hardening particles distribution information has been obtained. Mathematical apparatus has been developed

On the Issue of Nitrogen Solubility in Chromium-Nickel Grades of Steels

The article presents a comparative analysis of the solubility of nitrogen in chromium-nickel grades of steels. It is revealed that the existing theoretical calculations on the solubility of nitrogen in chromium-nickel steels can be applied only to austenitic grades of steels

Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector

The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV for the direct photon emission in the K- --> pi- pi0 gamma decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37+-0.39(stat)+-0.10(syst)]*10^(-5) obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.Comment: 13 pages, 8 figure