scholarly journals Production of ferroalloys in rotary tilting furnaces

2021 ◽  
pp. 19-23
Author(s):  
S. L. Rovin ◽  
L. E. Rovin
Keyword(s):  
Machine Building ◽  
Maximum Efficiency ◽  
Active Oxidation ◽  
Reduction Processes ◽  
Small Production ◽  
Building Enterprise ◽  
New Generation

The article presents an analysis of methods that can be used for low‑tonnage production of ferromanganese, ferrosilicon and other ferroalloys in the conditions of a machine‑building enterprise using its own waste, including dispersed. It is proposed to carry out the production of ferroalloys in rotary tilting furnaces (RNP) of a new generation, which have maximum efficiency when heating and melting dispersed materials, allow active oxidation and reduction processes and are able to provide the necessary profitability even with small production volumes.

scholarly journals Some methods of improving the quality of electronic archives at the machine-building enterprise

2021 ◽  
Vol 190 ◽  
pp. 18-22
Author(s):  
Polina Abrosimova ◽  
Stepan Sivkov ◽  
Galina Romanova ◽  
Alexandr Mashkin
Keyword(s):  
Machine Building ◽  
Building Enterprise

New Promising Generation of Twin-Gondola LNG Carriers Optimized with the Aid of CFD Calculations

2005 ◽  
Author(s):  
Henk V. Valkhof ◽  
Eduardo Minguito ◽  
Klaas Kooiker
Keyword(s):  
Viscous Flow ◽  
Far East ◽  
Point Of View ◽  
Maximum Efficiency ◽  
Hull Form ◽  
Overall Design ◽  
Computational Fluid Dynamics Cfd ◽  
New Generation ◽  
Hydrodynamic Optimization ◽  
Adequate Design

As natural gas is becoming an important energy source, a large fleet is needed to transport it in liquefied form across the oceans in specially designed LNG carriers from mainly the Middle East towards the Far East. During the overall design process of such a vessel the shape of the hull form and its propulsors play an important role from a hydrodynamic point of view. This paper describes the design of a twin-gondola LNG carrier for Navantia. The twingondola aft body has proven to be an adequate design concept, but due to the complexity of the flow around the aft body the design should be carried out with great care. Computational Fluid Dynamics (CFD) tools are extremely valuable in the hydrodynamic optimization process of the hull. In this design both potential flow codes and viscous flow codes have been used to obtain the optimum hull form. With the results of the PARNASSOS viscous flow calculations it was possible to make decisions with regard to the horizontal angle and the inclination of the gondolas, and the slope of the buttocks in the area between the gondolas. Special attention has been paid to avoid flow separation around the aft body. The gondolas have been oriented in such a way that maximum efficiency is achieved. The performance of the resulting design has been verified by model tests in MARIN’s Deep Water Towing Tank. Given the very promising results of this new generation of LNG carriers, achieving besides the excellent propulsive properties also a higher payload target, the yard became more competitive and is expecting quite some orders for this particular ship type.

scholarly journals THE FORMATION OF METHEMOGLOBIN BY STREPTOCOCCUS VIRIDANS

1916 ◽  
Vol 24 (4) ◽  
pp. 315-327 ◽  
Author(s):  
Francis G. Blake
Keyword(s):  
Blood Cells ◽  
Chemical Nature ◽  
Oxidation Process ◽  
Streptococcus Viridans ◽  
Bacterial Cells ◽  
Active Oxidation ◽  
Oxidation Processes ◽  
Reduction Processes ◽  
Methemoglobin Formation ◽  
Metabolic Activities

Cultures of Streptococcus viridans when brought into contact with red blood corpuscles have the power of transforming oxyhemoglobin into methemoglobin. The reaction occurs only in the presence of living streptococci when they are able to carry on their metabolic activities. The intensity of the reaction runs roughly parallel with the period of growth and multiplication of the bacteria and gradually diminishes and disappears as growth ceases. There is no apparent relation between the activity of a given strain of Streptococcus viridans in producing methemoglobin and its source or virulence. If the streptococci are suspended in salt solution they are unable to change oxyhemoglobin into methemoglobin unless some nutrient substance is present. Of the various nutrient substances tested dextrose is the most efficient in enabling the organisms to bring about the reaction. The reaction does not occur in the absence of oxygen, and is retarded by an excess of oxygen. Substances which tend to reduce the metabolic activities of the bacteria to a minimum exert an inhibitory action on methemoglobin formation. While not definitely proving it to be so, the results obtained in the above experiments strongly support the supposition that the reaction is not due to injurious substances produced by the bacteria or to products arising from the decomposition of the nutrient material present, but rather to the metabolic activities of the bacteria themselves when they are surrounded by environmental conditions which render growth and multiplication possible. The exact chemical nature of the change of oxyhemoglobin to methemoglobin is not known, but it is probably an oxidation process or a combination of reduction and oxidation processes, as pointed out by Heubner. As Cole has shown, the action of aminophenol is of great interest in this connection, in that it acts like a catalytic agent in being able to transform much more hemoglobin into methemoglobin than would be possible if the reaction were a simple molecular one. The metabolic activities of bacteria are largely in the nature of oxidation and reduction processes. The transformation of oxyhemoglobin into methemoglobin by streptococci of the viridans type, therefore, may be analogous to the action of such substances as aminophenol, and the reaction may be due to the active oxidation and reduction processes occurring in the neighborhood of the bacterial cells. The failure of the reaction to occur in the absence of oxygen and its retardation in the presence of an excess of oxygen, both with streptococci and with pneumococci (Cole) would seem to support this theory. Such results, however, may be due to the abnormal conditions surrounding the bacteria with consequent inhibition of their metabolic activities. Cole concluded as the result of his study of methemoglobin formation by pneumococci that since bacteria may injure red blood cells apparently by disturbances in oxidation in the immediate neighborhood of the organisms rather than by the production of a definite toxin, it is possible that bacteria may injure other tissue cells in a like manner and that the pathological effects produced by these bacteria may be explained on this basis. The experimental results recorded above have shown that the formation of methemoglobin by Streptococcus viridans in no way differs from its formation by pneumococci, and they lend support to the theory that bacteria may be injurious to tissues because of the disturbances in oxidation brought about by the metabolic activities of the organisms, especially those associated with growth and multiplication. It is believed that this theory may be particularly applicable to the pathological effects caused by Streptococcus vindans because the lesions produced by it, whether single or multiple, both in man and in experimental animals, are prone to be localized and associated with the actual presence of the streptococci in the lesions.

scholarly journals RISK ASSESSMENT OF HEALTH DISORDERS IN EMPLOYEES AT THE MACHINERY ENTERPRISE

2020 ◽  
Vol 99 (1) ◽  
pp. 76-79
Author(s):  
Lyubov A. Balabanova ◽  
S. K. Kamaev ◽  
A. A. Imamov ◽  
O. R. Radchenko
Keyword(s):  
High Risk ◽  
Working Conditions ◽  
Preventive Measures ◽  
Risk Groups ◽  
Machine Building ◽  
Occupational Factors ◽  
Building Enterprise ◽  
The Impact ◽  
Occupational Contact ◽  
Male Workers

Introduction. Adverse effects of environmental factors can cause dysfunction of organs and systems, hormonal dysfunction, genetic disorders, which can adversely affect the health of future generations. The aim is to study occupational risk factors and assess their impact on the health of male workers of machine-building enterprises, to develop preventive measures. Material and methods. The working conditions of 318 male workers of the main professions of the machine-building enterprise (miller, locksmith, electric and gas welder, turner, caster, etc.), having occupational contact with harmful occupational factors, were studied in comparison with 148 employees of the control group. Epidemiological, socio-hygienic, statistical and risk calculation methods were used. Results. 68.2% of respondents were found to have occupational contact with cutting fluid, 24.3% contact with chemicals, 14.4% - with heavy metals, 66.2% of respondents work in conditions of noise exposure, 40.1% - local vibration, 22.3% - in conditions of hypothermia, 14.4% - in conditions of overheating. Excess of maximum permissible concentrations of benzo(a)pyrene, aerosols of mineral oils, epichlorohydrin was detected in the air of the working zone. At workplaces, there were excess levels of noise, general vibration, thermal radiation. The impact of harmful occupational factors in the workplace was established to create a high risk to the health of workers. Conclusion. Working conditions of workers of the machine-building enterprise are mainly estimated as harmful. Critical organs and systems for the development of occupational pathology were identified, the high carcinogenic risk from exposure to benzo(a)pyrene was revealed. Employees of the machine-building enterprise were shown to have a high risk of oncology, respiratory diseases, central nervous system diseases, pathology in offspring. As a result, risk groups were formed and targeted preventive measures were proposed, including monitoring of the health status of high-risk groups, occupational selection, and medical examinations.

scholarly journals Integral risk assessment to optimize expenses for occupational safety measures at a machine-building enterprise

2019 ◽  
Vol 17 (3) ◽  
pp. 10-22
Author(s):  
Vitalii Bezsonnyi
Keyword(s):  
Risk Assessment ◽  
Occupational Safety ◽  
Workplace Safety ◽  
Machine Building ◽  
Assessment Procedure ◽  
Safety Measures ◽  
Safety And Health ◽  
Building Enterprise ◽  
Integral Assessment ◽  
Industrial Risks

In the absence of uniform and unified requirements for the assessment of industrial risks at an enterprise, the system approach remains the only tool for a comprehensive assessment of the workplace safety. Implementation of Occupational Safety and Health (OSH) system involves identifying, analyzing and reducing risks at the workplace. The purpose of the article is to calculate the minimum expenses for occupational safety measures and minimize production risks identified through the developed procedure for analyzing the hazards of the machine-building enterprise. The research methodology is based on the integrated use of qualitative and quantitative approaches to risk assessment, namely, structured assessment and integral assessment using the “rucksack problem” optimization model. The study identifies the risks that are most common and the most serious ones. The procedure of risk reduction is proposed, which is to determine the minimum costs for achieving each of the integral assessments for the machine-building enterprise. The practical value of work consists in the ability to directly apply the developed methodology for risk assessment at the enterprises of the machine-building industry, and to easily adapt the risk assessment procedure to other conditions.

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