Impact of metallurgical factors on the resistance of working ladle lining

This article examines the impact of main metallurgical factors on the stability of the working lining of steel ladles for plant that smelts low-alloy, carbon and low silicate assortment with turnover of more than 4,5 ladle heats/day, shares of heats processed on the ladle furnace – 100% and casting on continuous casting machine by open stream. By results of work the determinants factors and their share of influence on the stability of steel ladle have been estimated.В статье рассмотрено влияние основных металлургических факторов на стойкость рабочей футеровки сталеразливочных ковшей для завода, выплавляющего низколегированный, углеродистый и низкокремнистый сортамент с оборачиваемостью стальковша более 4,5 плавок/сутки, долей плавок обрабатываемых на установке «ковш-печь» (УКП) – 100% и разливкой на машине непрерывного литья заготовок (МНЛЗ) открытой струей. По результатам работы оценены определяющие факторы и их доля влияния на стойкость стальковша.У статті розглянуто вплив основних металургійних факторів на стійкість робочої футерівки сталерозливних ковшів для заводу, який виплавляє низьколегований, вуглецевий і низькокремнистий сортамент з оборотністю стальківша понад 4,5 плавок/добу, часткою плавок, що обробляються на установці «ківш-пічь» (УКП) – 100% і розливанням на машині неперервного лиття заготовок (МБЛЗ) відкритим струменем. За результатами роботи оцінено визначальні чинники і їх частку впливу на стійкість стальківша

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ДИНАМИКИ ДВИЖЕНИЯ ЮБКИ ПОРШНЯ В ЦИЛИНДРЕ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ

There examined method theoretical research of sectional piston skirt hydrodynamic lubrication, and influence of piston and connection rod groups options on it.В статье рассмотрена методика проведения теоретического исследования гидродинамической смазки юбки составного поршня, и влияние на нее конструктивных параметров деталей поршневой и кривошипно-шатунной групп

Multi-field continuum theory for medium with microscopic rotations

We derive the multi-field, micropolar-type continuum theory for the two-dimensional model of crystal having finite-size particles. Continuum theories are usually valid for waves with wavelength much larger than the size of primitive cell of crystal. By comparison of the dispersion relations, it is demonstrated that in contrast to the single-field continuum theory constructed in our previous paper the multi-field generalization is valid not only for long but also for short waves. We show that the multi-field model can be used to describe spatially localized short- and long wavelength distortions. Short-wave external fields of forces and torques can be also naturally taken into account by the multi-field continuum theory.Comment: 14 pages, 4 figures, submitted to International Journal of Solids and Structure

STUDY OF ACOUSTIC SIGNAL DURING LASER HYDROACOUSTIC PROCESSING OF BIOLOGICAL TISSUE BY MICROSECOND PULSES OF YTTERBIUM-ERBIUM GLASS LASER RADIATION

Subject of Research.The paper describes the research results of an acoustic signal recorded by a hydrophone while effect on a liquid by microsecond pulses of laser radiation with a wavelength of 1.54 μm and different time substructure. We discuss the influence of energy and time substructure of the laser pulse on the magnitude of generated pressure drops in the liquid and removal efficiency of cataract eye lens tissues. Method. Microsecond pulses of ytterbium-erbium glass laser radiation with different peak power of the "leading" spike and equivalent energy were delivered to the volume of distilled water through an optical fiber. The acoustic signal was registered with "NP 10-1" needle hydrophone (Dapco Inc., USA). An in vitro hydroacoustic treatment of cataract human eye lens was performed. Main Results. We obtained the dependences of the amplitude of the first (thermo-optical) and the second (associated with "collapse-rebound" process of a steam-gas cavity) components of the acoustic signal on the pulse energy for laser pulses with different time substructures. It was established that with an increase in the peak power of the "leading" spike of microsecond pulse, the threshold for the appearance of the second component decreases, and the maximum amplitude of both components increases. The angular distributions of the amplitude of acoustic signal components were obtained. It was found that the first component has a pronounced maximum amplitude in a direction perpendicular to the optical axis of the fiber, whereas the angular distribution of the second component is more uniform. In the in vitro experiment, it was shown that an increase in the peak power of the "leading" spike results in a significant increase in the removed volume and removal efficiency of the human cataract eye lens. Practical Relevance. The obtained results can be used to optimize the parameters of laser radiation for processing of tissue surrounded by a liquid, for example, during laser cataract extraction

High-frequency hopping conductivity in the quantum Hall effect regime: Acoustical studies

The high-frequency conductivity of Si delta-doped GaAs/AlGaAs heterostructures is studied in the integer quantum Hall effect (QHE) regime, using acoustic methods. Both the real and the imaginary parts of the complex conductivity are determined from the experimentally observed magnetic field and temperature dependences of the velocity and the attenuation of a surface acoustic wave. It is demonstrated that in the structures studied the mechanism of low-temperature conductance near the QHE plateau centers is hopping. It is also shown that at magnetic fields corresponding to filling factors 2 and 4, the doped Si delta- layer efficiently shunts the conductance in the two-dimensional electron gas (2DEG) channel. A method to separate the two contributions to the real part of the conductivity is developed, and the localization length in the 2DEG channel is estimated.Comment: 8pages, 9 figure

Экспериментальное исследование напряженно-деформированного состояния юбки поршня двигателя внутреннего сгорания на безмоторном стенде

The article describes the features developed by the authors of the profiling method of the piston skirt, provides the main parameters that affect the lubrication conditions of the piston skirt and the magnitude of mechanical losses. In computational studies, the basic formulas are given for determining the thickness of the oil layer in a piston skirt - cylinder sleeve conjunction to assess the nature of friction. To determine the deformations, the finite element method is used on the spatial model of the piston. To verify the finite element model, a stand for experimental studies was developed. The article describes the developed stand, the methodology and results of experimental studies of the stress-strain state of the two-piece piston skirt obtained at this stand and a comparative analysis of the results of the calculated and experimental studies of the stress-strain state of the two-piece piston skirt of a diesel engine. The research results showed that the developed stand can be used to verify mathematical models for calculating the stress-strain state of the piston skirt in the pilot production of internal combustion engine pistons to accelerate and reduce the cost of the piston design development process, as well as the results of experimental studies obtained at the stand, can be used as initial data for the developed mathematical model of the dynamics of the movement of the piston and the profiling of the piston skirt.В статье представлены особенности разработанной авторами методики профилирования юбки поршня, приведены основные параметры, влияющие на условия смазывания юбки поршня и величину механических потерь. В расчетных исследованиях даны основные формулы для определения толщины масляного слоя в сопряжении «юбка поршня - цилиндр» для оценки характера трения. Для определения деформаций используется метод конечных элементов на пространственной модели поршня. Для верификации конечно-элементной модели был разработан стенд для экспериментальных исследований. В статье описаны разработанный стенд, методика проведения и результаты экспериментальных исследований напряженно-деформированного состояния юбки составного поршня, полученные на данном стенде, выполнен сравнительный анализ результатов расчетных и экспериментальных исследований напряженно-деформированного состояния юбки составного поршня дизеля. Исследование показало, что разработанный стенд может применяться для верификации математических моделей расчета напряженно-деформированного состояния юбки поршня в опытном производстве поршней двигателя внутреннего сгорания для ускорения и удешевления процесса разработки их конструкции. Результаты экспериментальных исследований, полученные на стенде, также могут быть использованы в качестве исходных данных для разработанной математической модели динамики движения поршня и профилирования юбки поршня

Search for light pseudoscalar sgoldstino in K- decays

A search for the light pseudoscalar sgoldstino production in the three body K- decay K-->pipi0P has been performed with the ISTRA+ detector exposed to the 25 GeV negative secondary beam of the U70 proton synchrotron. No signal is seen. An upper limit for the branching ratio Br(K->pipi0P), at 90% confidence level, is found to be around 9*10**-6 in the effective mass m(P) range from 0 till 200 MeV, excluding the region near m(pi0) where it degrades to 3.5*10**-5.Comment: 10 pages, LATEX, 8 EPS figures, revised version, to be published in Phys.Lett.

High statistic measurement of the K- -> pi0 e- nu decay form-factors

The decay K- -> pi0 e- nu is studied using in-flight decays detected with the ISTRA+ spectrometer. About 920K events are collected for the analysis. The lambda+ slope parameter of the decay form-factor f+(t) in the linear approximation (average slope) is measured: lambda+(lin)= 0.02774 +- 0.00047(stat) +- 0.00032(syst). The quadratic contribution to the form-factor was estimated to be lambda'+ = 0.00084 +- 0.00027(stat) +- 0.00031(syst). The linear slope, which has a meaning of df+(t)/dt|_{t=0} for this fit, is lambda+ = 0.02324 +- 0.00152(stat) +- 0.00032(syst). The limits on possible tensor and scalar couplings are derived: f_{T}/f_{+}(0)=-0.012 +- 0.021(stat) +- 0.011$(syst), f_{S}/f_{+}(0)=-0.0037^{+0.0066}_{-0.0056}(stat) +- 0.0041(syst).Comment: 11 pages, 8 figures. Accepted by Phys.Lett.

Measurement of the Dalitz plot slope parameters for K- -> pi0 pi0 pi- decay using ISTRA+ detector

The Dalitz plot slope parameters g, h and k for the K- -> pi0 pi0 pi- decay have been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV negative secondary beam of the U-70 PS. About 252 K events with four-momenta measured for the pi- and four involved photons were used for the analysis. The values obtained g=0.627+/-0.004(stat)+/-0.010(syst), h=0.046+/-0.004(stat)+/-0.012(syst), k=0.001+/-0.001(stat)+/-0.002(syst) are consistent with the world averages dominated by K+ data, but have significantly smaller errors.Comment: LaTeX, 10 pages, 8 eps-figures, update of IHEP 2002-1