Анализ возможных путей снижения содержания серы в чугуне

One of the ways to increase the energy efficiency and intensity of blast furnace smelting, especially when using pulverized coal fuel, is to increase the hot strength of coke. In the conditions of OJSC NLMK, an oil additive was introduced into the coal charge to improve the coke quality. At the same time, sulfur content in the coke increases, and, consequently, sulfur content in the cast iron increases as well. In this regard, the task of finding ways to improve the desulfurization of cast iron in blast furnace becomes urgent. The main factors determining the desulfurization of cast iron are slag basicity, content of MgO oxide in it, temperature of the smelting products, and the slag viscosity. The purpose of this work was to compare the efficiency of sulfur removal by increasing the slag basicity and MgO content. On the basis of well-known equations, an algorithm was developed that allows the problem to be solved. It was established that an increase in MgO content in the slag promotes desulfurization of cast iron to a greater extent than a basicity increase. In addition, an increase in MgO content by 1 % is accompanied by an increase in slag yield by 3.0 – 3.5 kg/t of cast iron. At the same time, an increase in basicity by 0.01 leads to an increase in the slag yield by 4 – 5 kg/t of pig iron. Consequently, reducing the sulfur content in pig iron by increasing the slag basicity requires less heat. In terms of the specific consumption of coke, difference in heat demand is 0.4 – 0.5 kg/t of pig iron. It is shown that with an increase in MgO content in the slag, the slag viscosity at a temperature of 1450 °C increases to a lesser extent than with an increase in basicity. © 2020 National University of Science and Technology MISIS. All rights reserved

Diagnosis and comparative analysis of surgical treatment of patients with liver alveococcosis

Rationale. Alveococcosis is a rare disease, its diagnosis and treatment depend on surgical techniques, equipment and clinical experience. The aim. To develop a diagnostic algorithm and compare the results of surgical treatment of patients with liver alveococcosis in different periods of time.Materials and methods. At the first stage, we carried out a retrospective analysis (1995–2007) of 33 patients with alveococcosis (a comparison group). At the second stage, a prospective clinical study (2008–2021) was performed on 39 patients (the main group). The number of patients was determined in accordance with the inclusion and exclusion criteria, and the study groups were comparable in age, sex, parasite localization (p > 0.05). For the names of operations, the WHO classification of alveococcosis was used.Results. In the main group, there is an increase in the applicability of: enzyme immunoassay; ultrasound and computed tomography; biopsy. Complications decreased by 2.7 times from 54.6 % in the comparison group to 20.6 % in the main group (χ2 = 8.97; df = 1; p = 0.003). The average duration of operations, as well as the average volume of blood loss in the comparison group and the main group were, respectively: with atypical resection – 220.4 and 180.2 min (p = 0.003), 640.1 and 480.0 ml (p = 0.005); with anatomical resection – 296.2 and 247.2 min (p = 0.002), 1450.2 and 1150.3 ml (p = 0.018); with cytoreductive resection – 230.2 and 200.1 min (p = 0.004), 860.3 and 670.4 ml (p = 0.001). There were 13 (39 %) cytoreductive resections in the comparison group, and 3 (8 %) in the main group (χ2 = 4.74; df = 1; p = 0.029).Conclusion. Timely diagnosis of alveococcosis leads to an increase in the number of radical resections, and modern surgical technologies and equipment can reduce the time of surgery, blood loss and the number of complications

IMPROVEMENT OF TREATMENT OF UNFORMED DUODENAL AND HIGH JEJUNAL FISTULAS

This article shows many years of surgical experience of treatment of unformed duodenal and high jejunal fistulas using specific combined methods in main treatment group. The review covers the period from 2000 to 2016 years, which includes treatment of 132 patients who suffered from unformed duodenal and high jejunal fistulas. The research was conducted on the basis of the Republic Clinical hospital of G.G. Kuvatov in Bashkortostan. We followed the purpose of analysis and evaluation of the structure and quantity of early postoperative complications, including purulent-septic complications, as well as postoperative lethality, by comparing the main and control groups of treated patients, who received different kinds of therapy of unformed duodenal and jejunal fistulas. The treatment complex (main treatment group) consists of local use of collagen to strengthen intestinal sutures; selective injections of angioprotectors to blood vessels to improve microcirculation and trophic tissues; laser and antibiotic therapy for better eradication of microorganisms. The obtained results showed that the technique developed by us allowed to reduce the frequency of inconsistency of intestinal sutures, the number of newly formed intestinal fistula and purulent-septic complications in the treatment of patients with unformed duodenal and high jejunal fistulas

The use of whole genome amplification for genomic evaluation of bovine embryos

The integration of high technologies into livestock production has been actively occurring in the last decade in the countries with a developed animal breeding. First of all, we are talking about reproductive technologies (IVF) and genomic technologies (general genomic evaluation of animal and genomic evaluation of breeding value). Combining reproductive and genomic technologies is a promising approach that allows receiving highquality breeding cattle in the shortest possible time. The basis of the proposed technology for accelerated reproduction of high-value breeding cattle is to obtain information about the genome of the embryo for genomic evaluation. The amount of genetic material that can be obtained for research is extremely limited, as it is necessary to preserve the viability of the embryo. The stage of the whole genome amplification was introduced to obtain a high quality of genetic material in a sufficient quantity. The main purpose of this work is to assess the possibility of using embryo biopsy specimens (bsp) for embryo genotyping using microarray chips and predicting the carrier status of lethal haplotypes at the embryo stage. We obtained 100 cattle embryos, of which 78 biopsy specimens were taken to analysis. For the biopsies obtained we performed the whole genome amplification. The quality and quantity of DNA for all the 78 samples after the whole genome amplification were satisfactory for further genotyping. The quality of the performed genotyping was satisfactory and allowed the assessment of lethal haplotype carriers (determining the sex of the animal and identification of the carrier status for sevenHolsteinlethal haplotypes). We tested 78 embryos. From the genotyping analysis, there was detected one carrier status for three lethal haplotypes, HH0 (Brachyspina), HH5, and HCD. The carrier status of HH0 and HH5 was confirmed by testing the casual mutation using PCR analysis. The carrier status for HCD has not been confirmed by casual mutation analysis. The situation in which an animal is an HCD carrier, but not the carrier of a casual mutation, can be explained. The putative ancestor of the haplotype is the bull HOCAN000000334489 WILLOWHOLME MARK ANTHONY (year of birth is 1975), but a casual mutation associated with this disease has arisen only in his descendant HOCAN000005457798 MAUGHLIN STORM (year of birth is 1991). The results obtained confirm the importance of testing the casual mutation in the animals that are carriers of lethal haplotypes according to the genotyping data

Разработка системы релейно-векторного управления для многофазного полупроводникового преобразователя электрической энергии

A system of relay-vector control of current in the circuit of a polyphase electric machine has been developed. For this, on the basis of the analysis of electromagnetic processes in a multiphase semiconductor converter of electrical energy, its discrete mathematical model was created, which takes into account the redistribution of electromagnetic energy by individual spatial harmonic components, depending on the number of phases. Using this mathematical model, a method for relay control of spatial harmonic components of the input current of the converter in the “tube” has been developed. The formation of polyharmonic currents in each of the phases, conjugated in shape and phase with the voltage supplying the converter at each control period, is carried out by means of the optimal voltage vector of the semiconductor switch. To select the optimal control action, the objective function of the minimum deviation of the projections of the base voltage vectors of the semiconductor switch for the j-th combination of the state of the keys from the calculated control action determined by the mathematical model is used. An objective function of this type allows one to take into account different values of the amplitudes of the base voltage vectors of the semiconductor switch in the transformed orthogonal coordinate systems. In this case, there is no need to predict changes in the instantaneous values of the input current for one or two periods ahead, which is ensured by a decrease in the number of iterations to determine the optimal control action. To check the developed provisions, a simulation model of a nine-phase semiconductor converter of electrical energy with a relay vector control system was created. The results of the study of the model confirmed the adequacy of the developed technical solutions, the use of which will ensure the most complete realization of the own advantages of a multiphase electric machine in order to generally improve the weight, size and energy indicators of the autonomous power supply system.Разработана система релейно-векторного управления током в цепи многофазной электрической машины. Для этого на основе проведенного анализа электромагнитных процессов в многофазном полупроводниковом преобразователе электрической энергии создана его дискретная математическая модель, которая учитывает перераспределение электромагнитной энергии по отдельным пространственным гармоническим составляющим в зависимости от числа фаз. С использованием данной математической модели разработан способ релейного управления пространственными гармоническими составляющими входного тока преобразователя в «трубке». Формирование в каждой из фаз полигармонических токов, сопряженных по форме и фазе с питающим преобразователь напряжением на каждом периоде управления, осуществляется посредством оптимального вектора напряжения полупроводникового коммутатора. Для выбора оптимального управляющего воздействия используется целевая функция минимума отклонения проекций базовых векторов напряжения полупроводникового коммутатора при j-й комбинации состояния ключей от расчетного управляющего воздействия, определенного посредством математической модели. Целевая функция такого вида позволяет учесть различные значения амплитуд базовых векторов напряжения полупроводникового коммутатора в преобразованных ортогональных системах координат. При этом отсутствует необходимость прогнозирования изменения мгновенных значений входного тока на один или два периода вперед, что обеспечено уменьшением количества итераций для определения оптимального управляющего воздействия. Для проверки разработанных положений создана имитационная модель девятифазного полупроводникового преобразователя электрической энергии с системой релейно-векторного управления. Результаты исследования модели подтвердили адекватность разработанных технических решений, применение которых позволит обеспечить наиболее полную реализацию собственных преимуществ многофазной электрической машины в целях общего улучшения массогабаритных и энергетических показателей автономной системы электроснабжения

Анализ особенностей магнитного поля синхронной электрической машины с многофазной дробной зубцовой обмоткой в полигармоническом режиме работы

An analytical model has been developed for calculating magnetic field in a multiphase synchronous electric machine with fractional toothed windings. For this, a harmonic analysis of the distribution functions of the magnetic field of excitation and the magnetic field of the armature reaction was carried out, taking into account the presence of higher harmonic components in the function of the magnetomotive force of permanent magnets, variable magnetic conductivity of the air gap, polyharmonic mode of operation of a multiphase electric machine and a non-sinusoidal law of variation of spatial winding functions. As a result of the analysis, the substantiation is given that in the investigated electric machine a nine-phase winding can extract with the greatest efficiency the harmonic components of the first and third order of a rotating magnetic field to create flux linkage and induce an electromotive force (as well as create a magnetomotive force with prevailing spatial harmonics of the first and third order). In the investigated electric machine, the amplitudes of the working harmonics of the induction of the modulated magnetic field of the armature reaction can be increased due to the modulation of the inoperative harmonics of the magnetomotive force of the armature response by the stator teeth to the first and third order. To check the developed provisions, a magnetostatic vector model of the magnetic field of the investigated electric machine was created. The simulation results confirmed the high efficiency of the developed analytical model for calculating the magnetic field in a synchronous electric machine with fractional toothed windings. The use of such a model will make it possible to reveal most reliably the influence of the geometricparameters of the magnetic circuit and the multiphase winding circuit on the nature of the change in the functions of the magnetic field in the air gap with the lowest time costs in the process of optimizing an electric machine.Разработана аналитическая модель для расчета магнитного поля в многофазной синхронной электрической машине с дробными зубцовыми обмотками. Проведен гармонический анализ функций распределения магнитного поля возбуждения и магнитного поля реакции якоря с учетом наличия высших гармонических составляющих в функции магнитодвижущей силы постоянных магнитов, переменной магнитной проводимости воздушного зазора, полигармонического режима работы многофазной электрической машины и несинусоидального закона изменения пространственных обмоточных функций. В результате анализа приведено обоснование, что в исследуемой электрической машине девятифазная обмотка может извлекать с наибольшей эффективностью гармонические составляющие первого и третьего порядков вращающегося магнитного поля для создания потокосцепления и наведения электродвижущей силы (а также создавать магнитодвижущую силу с преобладающими пространственными гармониками первого и третьего порядков). В исследуемой электрической машине амплитуды рабочих гармоник индукции модулированного магнитного поля реакции якоря могут быть увеличены за счет модуляции нерабочих гармоник магнитодвижущей силы реакции якоря зубцами статора до первого и третьего порядков. Для проверки разработанных положений создана магнитостатическая векторная модель магнитного поля исследуемой электрической машины. Результаты моделирования подтвердили высокую результативность разработанной аналитической модели для расчета магнитного поля в синхронной электрической машине с дробными зубцовыми обмотками. Применение такой модели позволит наиболее достоверно выявить влияние геометрических параметров магнитной цепи и схемы многофазной обмотки на характер изменения функций индукции магнитного поля в воздушном зазоре при наименьших временных затратах в процессе оптимизации электрической машины

Effective Targeted Chemoprophylaxis of Recurrent Liver Echinococcosis with Haplotype CYP1A2F1*A/A: a Clinical Case

Background. One of the main long­term quality criteria for treatment and prevention of echinococcosis is postoperative relapse, which rate varies widely within 3–54% between medical facilities. The genetic traits of recurrent liver echinococcosis comprise an important subject of research into its etiopathogenetic factors for  an effective prognosis of cyst relapse and treatment personalisation.Materials and methods. Bashkir State Medical University (Ufa, Russia) provided facilities to study targeted  chemoprophylaxis efficacy in a case of relapsed liver echinococcosis with haplotype CYP1A2F1*A/A (AA) and the  UM phenotype of ultrarapid albendazole sulfoxide­to­albendazole sulfone metaboliser.Results and discussion. The clinical case presented illustrates the rationale behind personalised  chemoprevention of recurrent echinococcosis with albendazole based on genotyping data. Genotyping allows  detection of an ultrafast metaboliser haplotype in blood implicating a rapid degradation of administered albendazole, reduced antiparasitic impact of drug therapy and more feasible relapse, in contrast with a normal metaboliser phenotype.Conclusion. A successful secondary prevention of relapsed echinococcosis suggests the efficacy of personalising  albendazole­based chemoprophylaxis of recurrent echinococcosis with genotyping data

Perforated Peptic Ulcer Combined with Posttraumatic Diaphragmatic Hernia in Third Gestation Trimester: a Clinical Case

Background. Gastric and duodenal ulcers are extremely rare in pregnancy, according to published literature. Peptic ulcer is found in 1 per 4,000 pregnant women, a figure probably underestimated due to its hampered diagnosis in pregnancy. Pregnancy peptic ulcer is considered less expected. Perforated gastric and duodenal ulcers comprise about 1.5 % of total acute abdominal diseases, and the perforation rate in ulcer patients ranges within 5–15 %. This complication afflicts the ages of 20–40 years in men much more frequently than in women. Three perforation types occur: free into abdominal cavity (87 %), contained (9 %), into lesser omentum and retroperitoneal tissue (4 %).Materials and methods. The clinical case describes surgical management of posttraumatic diaphragmatic hernia-comorbid perforated gastric ulcer in a pregnant woman in third trimester. Surgery with postoperative patient management enabled for a favourable outcome.Results and discussion. Perforation-entailing gastric and duodenal ulcers in pregnant women have received negligible attention due to rarity in clinical practice. Paul et al. described 14 cases of duodenal perforation in pregnancy, all fatal.Conclusion. Early diagnosis of surgical pathology during gestation is still difficult contributing to the development of severe complications associated with high mortality. The patient’s admission to a level III interspecialty hospital was key to enable a timely consilium-driven decision of caesarean intervention for saving the child, diagnosing intraoperatively life-threatening complicated surgical diseases and opting for radical surgery that ended in a favourable outcome