Modeling of agglomerates formation and evolution at combustion of aluminized propellants in intra-chamber environments

In the present paper, the solution of the problem of agglomerates parameters calculation in combustion chamber environments is described. For this, a method of two-dimensional axisymmetric multiphase quasistationary flow calculation has been developed. The method uses previously developed models of agglomerates formation and their evolution within multiphase flow with considering of interactions between agglomerates and gaseous combustion products. Parametric study of the developed models with respect to intra-chamber environments has been performed

New Generation of High-Energy Chemical Propellants Based on Nano-Components

A possibility of designing propellant, in which the energy of intermolecular interaction in addition to chemical energy can be used, is considered. Application fine nano-components (clusters) in similar propellants is supposed. The method, which is based on positions of nanothermodynamics, is developed for determination of thermodynamic functions of similar particles (enthalpy, chemical potential, chemical affi nity in relation to various environments etc.). It is considered that for set of particles positions of classical and statistical thermodynamics are to the full right. Application of optimizing procedure is discussed. The standard system of readout, ideology of В«supramoleculeВ» and principles of statistical thermodynamics are applied to searching nanoparticles thermodynamic functions. The comparative analysis of this method and the method of quantum chemistry is carried out. Effi ciency of the suggested method is demostrated. Results of calculations have allowed drawing a conclusion that use of fi ne nano-components allows increasing essentially an energy potential of the propellants. High activity of fi ne nanoparticles results in rather high probability of coagulation of these particles and their interaction with environment. It is obvious that realization of this phenomena leads to sharp falling of a store of fine nanoparticles energy. Thus, a considerable problem at developing propellants on the basis of the specifi ed components is stabilization of nanoparticles. The analysis of various ways of this problem solution is carried out. It is shown that the method of steric (polymeric) stabilization of nano-particles is preferable. The estimation of stabilized nanoparticles characteristics and of stabilizing polymer weight is carried out. It is shown that application of polymeric coverings insignifi cantly reduces an energy potential of nanoparticles. The results obtained allow estimating the possibilities and operation conditions of different propellants

Влияние системы налогообложения на использование производственных ресурсов предприятий

The paper considers taxation problems of production resources in the Republic of Belarus. It has revealed disadvantages of the current taxation system and some recommendations on taxation rates have been proposed with the purpose to stimulate resource saving and innovation introduction at enterprises.Рассмотрены проблемы налогообложения производственных ресурсов в Республике Беларусь, выявлены недостатки существующей налоговой системы и предложены рекомендации по изменению ставок налогов с целью стимулирования ресурсосбережения и внедрения инноваций на предприятиях

Обратное рассеяние ультразвуковых волн как основа метода контроля структуры и физико-механических свойств чугунов

Increasing the reliability of control of cast iron structure and its physical and mechanical characteristics is an important scientific and technical task of the machine-building industry. The paper studies the possibilities of controlling the structure of cast irons using structural noise created by ultrasonic scattering on graphite inclusions of different shapes. The subject of the present studies was such characteristics of structural noise as amplitude-temporal A(t) and as root mean square value of the amplitude of the ultrasonic waves backscattering field AN, compared with the data on ultrasonic velocity and strength or tensile strength of cast iron samples. As a result of the studies, a significant difference between the amplitude parameters of the AN structural noise obtained for samples with different shapes of graphite inclusions at 5 MHz was revealed for the first time. So, for example, for samples of gray cast iron (Russian: СЧ10, СЧ15, СЧ20, СЧ25), having predominantly plate-like form of graphite inclusions, the value of AN on 14–15 dB exceeds that measured in high-strength specimens of the cast iron with the prevailing form of spherical graphite inclusions ВЧ50 (Russian), etc. At the same time growth of longitudinal ultrasonic velocity amounted to 20–25 %. The method of rejection of gray cast iron from high-strength cast iron according to the data of amplitude parameters of structural noise AN at unilateral and local sounding of the object without using an additional reference signal reflected from its oppositional wall is suggested.Повышение надёжности контроля структуры чугунов и их физико-механических характеристик является важной научно-технической задачей машиностроительной промышленности. В работе изучены возможности контроля структуры чугунов, используя структурный шум, создаваемый рассеянием ультразвуковых колебаний на графитовых включениях разной формы. Предметом настоящих исследований являлись такие характеристики структурного шума как амплитудновременные А(t) и среднеквадратичные амплитуды AN волн рассеяния, сопоставляемые с данными по скорости ультразвуковых колебаний, а также прочностью или временным сопротивлением на растяжение образцов чугунов. В результате исследований впервые выявлено существенное различие между амплитудными параметрами структурного шума AN, полученными для образцов с разной формой графитовых включений на частоте 5 МГц. Так, например, для образцов серого чугуна (СЧ10, СЧ15, СЧ20, СЧ25), имеющих преимущественно пластинчатую форму графитовых включений, величина AN на 14–15 дБ превышает ту, что измерена в высокопрочных чугунах с превалирующей формой включений графита шаровидной формы – ВЧ50. При этом, рост продольной скорости ультразвука с увеличением временного сопротивления составил ≈ 20–25 %. Предложен метод отбраковки серого чугуна от высокопрочного по данным амплитудных параметров структурного шума AN при одностороннем и локальном прозвучивании объекта без использования дополнительного опорного сигнала, отражённого от его оппозитной стенки

К вопросу о расчете оптимального объема поставки материала

The paper proposes a model which makes it possible to calculate optimum volume of material delivery to an enterprise. It provides minimum expenses which are intended for meeting annual material requirements.The proposed model takes into account imputed expenditures which are non-eamed revenue of the enterprise due to freezing of circulating medium at storage reserve.Calculative example of optimum volume of material delivery is given in the paper.Предложена модель определения оптимального объема поставки материала на предприятие, которая обеспечивает минимальные расходы на годовую потребность в материалах данного наименования.В рассмотренной модели учтены вмененные затраты, представляющие недополученный предприятием доход от «замораживания» оборотных средств в складском запасе.Приведен пример расчета оптимального объема поставки материала

Обоснование условий расчетов за продукцию

The paper proposes a model that presupposes granting more favorable payment (discount) conditions with the purpose to expedite payments for products. Dependence for calculation of discount rate has been deduced on the basis of information about an actual cost of debtor’s accounts receivable. The example of discount calculation depending on a maturity of debtor’s accounts receivable is given in the paper.Предложена модель предоставления покупателям льготных условий расчетов (скидок) за ускорение оплаты продукции. На основании информации о реальной стоимости дебиторской задолженности выведена зависимость для определения величины скидки. Приведен пример расчета скидок в зависимости от срока погашения дебиторской задолженности

Backscattering of Ultrasonic Waves as the Basis of the Method of Control of Structure and Physicо-Mechanical Properties of Cast Irons

Increasing the reliability of control of cast iron structure and its physical and mechanical characteristics is an important scientific and technical task of the machine-building industry. The paper studies the possibilities of controlling the structure of cast irons using structural noise created by ultrasonic scattering on graphite inclusions of different shapes. The subject of the present studies was such characteristics of structural noise as amplitude-temporal A(t) and as root mean square value of the amplitude of the ultrasonic waves backscattering field AN, compared with the data on ultrasonic velocity and strength or tensile strength of cast iron samples. As a result of the studies, a significant difference between the amplitude parameters of the AN structural noise obtained for samples with different shapes of graphite inclusions at 5 MHz was revealed for the first time. So, for example, for samples of gray cast iron (Russian: СЧ10, СЧ15, СЧ20, СЧ25), having predominantly plate-like form of graphite inclusions, the value of AN on 14–15 dB exceeds that measured in high-strength specimens of the cast iron with the prevailing form of spherical graphite inclusions ВЧ50 (Russian), etc. At the same time growth of longitudinal ultrasonic velocity amounted to 20–25 %. The method of rejection of gray cast iron from high-strength cast iron according to the data of amplitude parameters of structural noise AN at unilateral and local sounding of the object without using an additional reference signal reflected from its oppositional wall is suggested