337 research outputs found

    Structure of the Optimal Management System for Raw Materials, Fuel and Energy Resources in Blast-furnace Production

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    The structure of optimization model of optimal management of raw materials, fuel and energy resources in the blast-furnace shop of iron and steel works is represented. The following blocks are taken as system basis: (1) calculation of the set of parameters that characterize the thermal, gas-dynamic, slag and blasting modes for every blast furnaces of the shop during the base period; (2) calculation of linearized model coefficients (constants of transferring via different exposure pathways) individually for every blast furnace as well as properties of iron ore raw materials, fluxing additions, blasting parameters, parameters of fuel-enriched blast influencing the technical-and-economic indices of separate furnaces performance, their thermal, gasdynamic and slag operation modes in the course of blast-furnace melting according to UrFU-MMT blast-furnace production model within the base period; (3) solution of tasks that consider the optimal allocation of raw materials, fuel and energy resources for the project period of blast furnaces operation; (4) analysis of obtained results and providing of recommendations on the optimization of blast furnaces parameters. The developed functional model of optimal distribution of raw materials, fuel and energy resources for the engineering and technology personnel of blast-furnace shop is illustrated; the main functions and interconnections between the separate functional blocks are defined. The functions of created ‘Optimal management of raw materials, fuel and energy resources in the blast-furnace production’ software that is realized in the Microsoft Visual Studio 2017 (С# programming language) programming environment in the form of web application are pointed out. The program product provides the engineering and technology personnel of blast furnace shop of iron andsteel works with the opportunity to solve the tasks of optimal distribution of fuel and energy resources (natural gas and oxygen consumption) within the group of blast furnaces in the different technological situations. Keywords: blast-furnace production, resources distribution optimization, fuel and energy resources, raw material resources, functional modeling, decision support system, software developmen

    Assessing the shape of the viscoplastic iron-ore zone in a blast furnace

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    A mathematical model permits assessment of the position and shape of the viscoplastic iron-ore zone (cohesion zone) in a blast furnace and identification of a rational configuration for this zone on the basis of readily available information regarding the blast furnace in the baseline period. The model also permits the solution of design problems with variation in the furnace parameters. Modeling results are outlined for the baseline and design periods. © 2013 Allerton Press, Inc

    New words in human mutagenesis

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    <p>Abstract</p> <p>Background</p> <p>The substitution rates within different nucleotide contexts are subject to varying levels of bias. The most well known example of such bias is the excess of C to T (C > T) mutations in CpG (CG) dinucleotides. The molecular mechanisms underlying this bias are important factors in human genome evolution and cancer development. The discovery of other nucleotide contexts that have profound effects on substitution rates can improve our understanding of how mutations are acquired, and why mutation hotspots exist.</p> <p>Results</p> <p>We compared rates of inherited mutations in 1-4 bp nucleotide contexts using reconstructed ancestral states of human single nucleotide polymorphisms (SNPs) from intergenic regions. Chimp and orangutan genomic sequences were used as outgroups. We uncovered 3.5 and 3.3-fold excesses of T > C mutations in the second position of ATTG and ATAG words, respectively, and a 3.4-fold excess of A > C mutations in the first position of the ACAA word.</p> <p>Conclusions</p> <p>Although all the observed biases are less pronounced than the 5.1-fold excess of C > T mutations in CG dinucleotides, the three 4 bp mutation contexts mentioned above (and their complementary contexts) are well distinguished from all other mutation contexts. This provides a challenge to discover the underlying mechanisms responsible for the observed excesses of mutations.</p

    Simulation of heat-transfer processes and assessment of the viscoplastic parameters of iron ore in blast furnaces

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    Stages in the development of an information and simulation system for assessing the position and shape of the viscoplastic iron-ore zone (the cohesion zone) in the blast furnace are outlined. This system also permits diagnostics of the zone's optimal configuration on the basis of available operational information for the furnace in the baseline period. In addition, the system proves useful during the design period, with variation in the smelting parameters. The capabilities of the corresponding software are discussed, and its use in blast-furnace control at OAO Magnitogorskii Metallurgicheskii Kombinat is demonstrated. © 2013 Allerton Press, Inc

    Cyclotron resonance of extremely conductive 2D holes in high Ge content strained heterostructures

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    Cyclotron resonance has been observed in steady and pulsed magnetic fields from high conductivity holes in Ge quantum wells. The resonance positions, splittings and linewidths are compared to calculations of the hole Landau levels

    Optimal allocation of fuel and energy resources in the complex blast-furnace plants

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    The paper presents the model of optimal allocation of power resources in a blast furnace taking into account the change of smelting parameters. The optimization model allows to predict parameters of injected fuel on separate (at individual, in certain) blast furnaces in various technological situations. At problem formulation and task solution, the model considers the static characteristics describing the influence of changes of melting conditions on overall economic indicators of furnaces, the mathematical description external and internal limitations on operation of some blast furnaces and blast-furnace plant generally. Informational-modelling system optimization of allocation of natural gas in a blast-furnace plant was developed on the presented model. This model includes: input and adjustment of data; calculation module; optimization; output and the assaying of results. The results of comparative assaying of allocation of natural gas on the basis of operation data of the blast-furnace plant of OJSC “Magnitogorsk Iron and Steel Works ” are achieved. Analysis of the results shows that the optimization model of joint distribution of natural gas and oxygen allows to use effectively the available fuel and energy resources, taking account the technological limitations in the work of individual furnaces as well as a plant in general

    Temperature-driven single-valley Dirac fermions in HgTe quantum wells

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    We report on temperature-dependent magnetospectroscopy of two HgTe/CdHgTe quantum wells below and above the critical well thickness dcd_c. Our results, obtained in magnetic fields up to 16 T and temperature range from 2 K to 150 K, clearly indicate a change of the band-gap energy with temperature. The quantum well wider than dcd_c evidences a temperature-driven transition from topological insulator to semiconductor phases. At the critical temperature of 90 K, the merging of inter- and intra-band transitions in weak magnetic fields clearly specifies the formation of gapless state, revealing the appearance of single-valley massless Dirac fermions with velocity of 5.6×1055.6\times10^5 m×\timess1^{-1}. For both quantum wells, the energies extracted from experimental data are in good agreement with calculations on the basis of the 8-band Kane Hamiltonian with temperature-dependent parameters.Comment: 5 pages, 3 figures and Supplemental Materials (4 pages

    Algorithms and software for optimal management of raw materials, fuel and energy resources in blast furnace production

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    The structure of optimization model of optimal management of raw materials, fuel and energy resources in the blast-furnace shop of iron and steel works is represented. The following blocks are taken as system basis: 1) calculation of the set of parameters that characterize the thermal, gas-dynamic, slag and blasting modes for every blast furnaces of the shop during the base period; 2) calculation of linearized model coefficients (constants of transferring via different exposure pathways) individually for every blast furnace as well as properties of iron ore raw materials, fluxing additions, blasting parameters, parameters of fuel-enriched blast influencing the technical-and-economic indices of separate furnaces performance, their thermal, gas-dynamic and slag operation modes in the course of blast-furnace melting according to UrFU-MMK blast-furnace production model within the base period; 3) solution of tasks that consider the optimal allocation of raw materials, fuel and energy resources for the project period of blast furnaces operation; 4) analysis of obtained results and providing of recommendations on the optimization of blast furnaces parameters. The developed functional model of optimal distribution of raw materials, fuel and energy resources for the engineering and technology personnel of blast-furnace shop is illustrated; the main functions and interconnections between the separate functional blocks are defined. The functions of created "Optimal management of raw materials, fuel and energy resources in the blast-furnace production"software that is realized in the Microsoft Visual Studio 2017 (C# programming language) programming environment in the form of web application are pointed out. The program product provides the engineering and technology personnel of blast furnace shop of iron and steel works with the opportunity to solve the tasks of optimal distribution of fuel and energy resources (natural gas and oxygen consumption) within the group of blast furnaces in the different technological situations. © Published under licence by IOP Publishing Ltd

    Индикатор для оценки обеспеченности подвижным составом городского пассажирского транспорта общего пользования

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    The objective of the article is to develop and to substantiate adequacy of the proposed indicator for assessing availability of rolling stock for urban mass transit or urban passenger transport (UPT). As such an indicator, it is recommended to use a calculated indicator: a conventional one-hundred-seat vehicle. The currently used indicators characterising provision of UPT with vehicles, consider only the physical number of the latter. This does not provide an assessment of carrying capacity of UPT, considering the existing operating conditions (real operating speeds on the routes of UPT, the existing level of the coefficient of the fleet being used on the routes as compared to the total number of fleet units, etc.). The proposed indicator of availability of the rolling stock considers not only the natural number of vehicles, but also their passenger capacity, the indicated significant technical and operational indicators of the vehicle fleet. The basis for assessing the carrying capacity of the rolling stock fleet is a conventional one-hundred-seat bus, which performs transportation on routes with an average operating speed. For real buses, this basic unit is adjusted in accordance with real travel speeds and the prevailing values of technical and operational indicators. A similar adjustment is performed for real trolleybuses and tram cars, which makes it possible to level the operational differences in the rolling stock of various types of UPT to compare them in terms of carrying capacity.The methodology used in preparation of the article is based on the integrated use of scientific knowledge in the fields of applied science on operation of transport, statistics (statistical observation and accounting of the work of UPT), a comparative analysis of indicators used in various industries, in particular, in agriculture to assess the level of provision with the main production vehicles (conventional tractor), benchmarking research and development of Russian and foreign authors on the problem of improving operation of UPT.The indicator is intended for use in development and assessment of the level of implementation of programs for development of UPT and the urban environment, analysis of the quality of transport planning and services provided to passengers, comparisons of provision with vehicles in different cities.Целью статьи являются разработка и обоснование адекватности предлагаемого индикатора для оценки обеспеченности подвижным составом городского пассажирского транспорта (ГПТ). В качестве такого индикатора рекомендовано использовать расчётный показатель – условное стоместное транспортное средство. Используемые в настоящее время показатели, характеризующие обеспеченность ГПТ транспортными средствами, учитывают только натуральное число последних. Это не обеспечивает оценки провозных возможностей ГПТ с учётом сложившихся условий эксплуатации (реальные эксплуатационные скорости движения на маршрутах ГПТ, сложившийся уровень коэффициента выпуска подвижного состава на маршруты). Предложенный индикатор обеспеченности подвижным составом учитывает не только натуральное число транспортных средств, но и их пассажировместимость, указанные существенные технико-эксплуатационные показатели парка транспортных средств. За базу для оценки провозной способности парка подвижного состава принят условный стоместный автобус, выполняющий перевозки на маршрутах со средней эксплуатационной скоростью движения. Для реальных автобусов эта базовая единица корректируется в соответствии с реальными скоростями движения и сложившимися значениями технико-эксплуатационных показателей. Аналогичная корректировка выполняется для реальных троллейбусов и вагонов трамвая, что позволяет нивелировать эксплуатационные различия подвижного состава различных видов ГПТ с целью их взаимного сопоставления по провозной возможности.Использованная при подготовке статьи методология опирается на комплексное применение научных знаний в областях прикладной науки об эксплуатации транспорта, статистики (статистическое наблюдение и учёт работы ГПТ), сравнительного анализа индикаторов, применяемых в различных отраслях, в частности, в сельском хозяйстве для оценки уровня обеспеченности основными производственными средствами (условный трактор), бенчмаркинга исследований и разработок российских и зарубежных авторов по проблеме совершенствования деятельности ГПТ.Индикатор предназначен для использования при разработке и оценке уровня исполнения программ развития ГПТ и городской среды обитания, анализа качества транспортного планирования и обслуживания пассажиров ГПТ, сравнений обеспеченности транспортными средствами различных городов
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