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Number of results: 7
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Abstract

Diesel generator engines operate in wide load modes; therefore, it is necessary to change the percentage of the mixture of diesel and biodiesel fuel depending on the operating mode of the engine; this ensures its technical performance at the required level in all operating modes, including starting and stopping the engine. This article describes an algorithm for the operation of a diesel generator and an algorithm for determining the composition of the fuel mixture. During the study, the ratio between the components of the mixture changed, taking into account the load modes of operation of the diesel generator, indicators of fuel supply and the formulation of the fuel mixture to ensure optimal values of technical and economic indicators. To assess the efficiency of the flow of working processes in a diesel cylinder, their duration was selected, which is estimated by the duration of the processes of fuel injection, evaporation and combustion. Using the dynamic regulation of the composition of the diesel and biodiesel fuel, the total fuel consumption increased by 5.9%, but the cost of purchasing the fuel is reduced by 10% (at prices as of November 2021) and by 14.6% (based on prices as of the beginning of 2022) compared to engine operation with diesel fuel. This confirms the expediency of using the dynamic adjustment of the composition of the fuel mixture. In addition, even higher economic indicators can be achieved by using an autonomous power plant with a diesel power capacity higher than the generator capacity.
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Authors and Affiliations

Ihor Kupchuk
1
ORCID: ORCID
Serhii Burlaka
1
ORCID: ORCID
Alexander Galushchak
2
ORCID: ORCID
Tetiana Yemchyk
3
ORCID: ORCID
Dmytro Galushchak
1
Yrii Prysiazhniuk
1
ORCID: ORCID

  1. Engineering and Technology Faculty, Vinnytsia National Agrarian University, Ukraine
  2. Vinnytsia National Technical University, Ukraine
  3. Faculty of Economics and Entrepreneurship, Vinnytsia National Agrarian University, Ukraine
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Abstract

There are a huge number of objects constituting a storage place of coal mining waste in the coal basins in Poland and around the world. The article is a continuation of the study on the possibilities of using raw materials deposited on the coal mining waste dumping grounds on the example of the Przezchlebie dumping ground. The possibility of coal recovery from mining waste located on the dumping ground was analyzed. Tests on the quality parameters of waste were carried out, i.e. moisture and ash content, as well as the calorific value of raw waste. The relatively high calorific value and low ash content in the waste served as the basis for further tests related to the separation of coal. Tests on the mining waste enrichment using the complex based on the K-102 Komag pulse separator were carried out. As a result of coal separation, 7.66% of concentrate was obtained (in relation to feed) with the calorific value of 26.16 MJ/kg and ash content of 19.96%. Apart from mining waste, power plant waste (fly ash) can also be found on the dumping ground. They were subjected to tests for the possibility of using them in the production of construction materials, especially concrete and cement. Fly ash from the Przezchlebie dumping ground was classified as silica ash and it was found that it meets the requirements of Polish standard, except for the fineness of 42%. The separation of coal will eliminate the fire hazard on the dumping ground. A possible scenario of managing waste material on a dumping ground, which can be implemented in similar facilities, has been presented.

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Authors and Affiliations

Zenon Różański
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Abstract

Energy demand is increasing exponentially in the last decade. To meet such demand there is an urgent need to enhance the power generation capacity of the electrical power generation system worldwide. A combined- cycle gas turbines power plant is an alternative to replace the existing steam/gas electric power plants. The present study is an attempt to investigate the effect of different parameters to optimize the performance of the combined cycle power plant. The input physical parameters such as pressure ratio, air fuel ratio and a fraction of combustible product to heat recovery heat exchanger via gas turbine were varied to determine the work output, thermal efficiency, and exergy destruction. The result of the present study shows that for maximum work output, thermal efficiency as well as total exergy destruction, extraction of combustible gases from the passage of the combustion chamber and gas turbine for heat recovery steam generator is not favorable. Work output and thermal efficiency increase with an increase in pressure ratio and decrease in air fuel ratio but for minimum total exergy destruction, the pressure ratio should be minimum and air fuel ratio should be maximum.
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Bibliography

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Authors and Affiliations

Mohammad Nadeem Khan
1

  1. Department of Mechanical and Industrial Engineering, College of Engineering, Majmaah University, Majmaah 11952, Saudi Arabia
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Abstract

Footbridges, like all building structures, must be designed in a way that ensures their safe and comfortable use. Steel footbridges characterised by low vibration damping often turn out to be a structure susceptible to the dynamic influence of users during various forms of their activity. For these structures, the impact of running users may be a key type of dynamic load for the verification of the serviceability limit state due to vibrations. In the literature, there are several proposals for models of dynamic load generated by runners (models of ground reaction forces – GRF). The paper presents the characteristics, analyses and comparisons of selected GRF load models. The analyses were performed using the GRF recorded during the laboratory tests of runners (tests planned and carried out by the author) and the GRF determined using various load models. In order to illustrate the accuracy of the estimation of the dynamic response of the structure, depending on the GRF model used, dynamic field tests and dynamic numerical analyses of the selected steel footbridge were carried out. The obtained results were analysed and compared.
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Authors and Affiliations

Marek Pańtak
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, Warszawska 24, 31-155 Krakow, Poland
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Abstract

The pattern of pore water pressure dissipation from the one-dimensional consolidation test significantly affects the calculated value of the coefficient of consolidation. This paper discusses the interpretation methodology for laboratory dissipation data from the oedometer test with the pore water pressure measurements or Rowe cell test. In the analysis, the gradient-based algorithm for finding the optimal value of the coefficient of consolidation is used against experimental results, obtained for various fine-grained soils. The appropriate value of coefficient of consolidation is considered as one with the lowest associated error function, which evaluates fitness between the experimental and theoretical dissipation curves. Based on the experimental results, two different patterns of the pore water pressure dissipation are identified, and the saturation of the specimen was found to be the key factor in describing the change in the patterns. For the monotonically decreasing dissipation curve, an inflection point is identified. The values of degree of dissipation at the inflection point are close to the theoretical value of 53.4%.
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Authors and Affiliations

Bartłomiej Szczepan Olek
1
ORCID: ORCID

  1. Krakow University of Technology, Faculty of Civil Engineering, Warszawska 24, 31-155 Kraków, Poland
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Abstract

As of the spring of 2017, the HAŁDY Database is available on the Polish Geological Institute – NRI website. The geodatabase contains information and data on waste mineral raw materials collected on old heaps, industrial waste stock-piles and in post-mining settlers, from the Polish part of the Sudety Mountains. The article presents the types of data and information contained in the geodatabase and the methodology for their collection. As a result of four-year research works, field reconnaissance, archives and geological basic research, 445 objects of former mining and mineral processing were inventoried. There are 403 mine heaps, 16 industrial settlers, 23 stock-piles and 3 external dumps. These are mainly objects after coal mining and metal ores, including post-uranium. The greatest opportunities for the economic use of waste are associated with coal sludge accumulated in settlers of the liquidated Lower Silesian Coal Basin. The material from stone heaps after polymetallic, iron and fluorite ore mining is also easy to use. The issue of the economic use of post-flotation copper ore waste or the recovery of metals (including gold) from dumps of arsenic mining remains open. The limitation here is the efficiency of metal recovery technologies and environmental restrictions. Some of the objects are located in protected areas, which excludes the possibility of waste management. Some stock-piles and heaps should be carefully reclaimed and covered by environmental monitoring, due to their harmful impact on environmental components.

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Authors and Affiliations

Cezary Sroga
Stanisław Z. Mikulski
Wojciech Bobiński
Marek Adamski
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Abstract

Hydrogen is the fuel of the future, therefore many hydrogen production methods are developed. At present, fuel cells are of great interest due to their energy efficiency and environmental benefits. A brief review of effective formation methods of hydrogen was conducted. It seems that hydrogen from steam reforming of methanol process is the best fuel source to be applied in fuel cells. In this process Cu-based complex catalysts proved to be the best. In presented work kinetic equations from available literature and catalysts are reported. However, hydrogen produced even in the presence of the most selective catalysts in this process is not pure enough for fuel cells and should be purified from CO. Currently, catalysts for hydrogen production are not sufficiently active in oxidation of carbon monoxide. A simple and effective method to lower CO level and obtain clean H2 is the preferential oxidation of monoxide carbon (CO-PROX). Over new CO-PROX catalysts the level of carbon monoxide can be lowered to a sufficient level of 10 ppm.

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Authors and Affiliations

Maria Madej-Lachowska
Maria Kulawska
Jerzy Słoczyński

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