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    Wyświetlanie 1-15 z 15
    Tytuł:
    Algorithms for reliable networks deployment in mesh topology with flow control
    Autorzy:
    Debita, G.
    Staniec, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/226158.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    mesh
    network
    planning
    Opis:
    The article presents innovative methods for designing and controlling topology in mesh networks. The authors of the paper simulate the procedure of deploying a mesh structure and prove that the shortest path for such a network is also one with the least number of hops in the sense of intermediate nodes.
    Źródło:
    International Journal of Electronics and Telecommunications; 2010, 56, 1; 73-79
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reliable digital dead-time generator for the GaN HEMTs based H-bridge converters
    Autorzy:
    Svarny, Jiri
    Powiązania:
    https://bibliotekanauki.pl/articles/949890.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    dead-time generator
    delay-line
    GaN HEMTs
    H-bridge driver
    Opis:
    The paper deals with hardware solution of a fully digital dead-time generator. The circuit is applicable to the H-bridges based on any type of semiconductor switching devices including SiC, IGBT, Si-MOSFET and up-to-date GaN HEMTs. The generation of dead-times is ensured by commercially available silicon delay lines. High temperature stability is obtained by self-compensation of propagation delay of logic elements thanks to the symmetry of design topology. The circuit can be set-up to generate dead-times in the range from 10 ns to 500 ns. Longer dead-times are also available by simple cascading of the silicon delay lines. The key motivation for development of the circuit was unavailability of ready to use integrated solutions on the market. Moreover, contrary to the other solutions the proposed circuit is immune to prospective oscillations of an input PWM signal. The paper brings a detailed analysis of the circuit principle, results of the verification of a sample solution and an example of practical application as well.
    Źródło:
    Archives of Electrical Engineering; 2020, 69, 4; 781-792
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    RBCP-WSN : The Reliable Biderectional Control Protocol for Wireless Sensor Networks
    Autorzy:
    Golański, M.
    Schoeneich, R. O.
    Zgid, D.
    Franciszkiewicz, M.
    Kucharski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/226928.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    routing protocols
    MANET
    WSN
    Opis:
    This paper presents the Reliable Bidirectional Control Protocol (RBCP) protocol, which is a transport protocol for Wireless Sensor Networks (WSN), focused on managing sensors' behaviour. It aims to be a utility for reliable control data transferring from source to destination unit in the network. Considering the related studies on transport protocols, which are mostly dedicated to a single-direction reliable data transport, RBCP is the answer for the lack of control mechanisms in WSNs based on bidirectional communication. The first part of this paper is focused on general presentation of the proposed solution. In the next part, evaluation of the idea and final functionality are discussed. It will finally show the results of undergone testing stage.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 2; 201-207
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Being more idiographic in the nomothetic world
    Autorzy:
    Korulczyk, Tomasz
    Biela, Adam
    Blampied, Neville
    Powiązania:
    https://bibliotekanauki.pl/articles/2129704.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    longitudinal research
    Modified Brinley Plot
    Reliable Change Index
    idiographic approach
    IBM SPSS Statistics
    Opis:
    Since psychology emerged as an independent field of knowledge, there has been no consensus as to how it should develop, either, in the idiographic or nomothetic way. In the course of time, due to a commitment to what was seen as objectivity in science, the nomothetic approach came to dominate psychology. Thus, researchers used mostly quantitative psychometric methods to establish general rules of human behaviour. In doing so, the essence of nomothetic research is to be extremely careful when interpreting results not to make a reasoning mistake such as the ecological fallacy, as may happen when a researcher draws conclusions about nature of the individual in the group based on average results of the whole group. In the article, we presented two methods for longitudinal research designs which address this problem, and give more idiographic information about participants; via the Reliable Change Index and the Modified Brinley Plot. Finally, we provide a IBM SPSS Statistics syntax automatizing the whole process of computation for these new features.
    Źródło:
    Polish Psychological Bulletin; 2019, 50, 2; 207-216
    0079-2993
    Pojawia się w:
    Polish Psychological Bulletin
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Behave yourself! NAS-50 as a reliable tool for assessment of adolescent self-control
    Autorzy:
    Fryt, Joanna
    Smoleń, Tomasz
    Czernecka, Karolina
    Powiązania:
    https://bibliotekanauki.pl/articles/2121544.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    NAS-50
    self-control
    adolescents
    cognitive control
    impulsivity
    Opis:
    Self-control is a complex and multifaceted construct that can be regarded as an individual trait that follows its own developmental trajectory. In the presented study we used NAS-50 for the assessment of self-control in adolescents and young adults. Since the questionnaire has not been used before in underage participants we tested its reliability in adolescent and adult samples. We also investigated possible age and gender differences in self-control abilities as well as relations between NAS-50 and behavioral measures of cognitive control and impulsivity. Although the sample was quite small, the reliability of the questionnaire was similar to the results achieved by its authors. According to the predictions in the literature we did not find relations between NAS-50 and behavioral measures of cognitive control and impulsivity. We also did not observe significant age differences in the assessment of self-control abilities. The theoretical relevance of our results is discussed.
    Źródło:
    Polish Psychological Bulletin; 2019, 50, 1; 36-42
    0079-2993
    Pojawia się w:
    Polish Psychological Bulletin
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Review on Feasible and Reliable Underwater Wireless Optical Communication System for achieving High Data Rate and Longer Transmission Distance
    Autorzy:
    Joseph, Lenin
    Anandan, Sangeetha
    Powiązania:
    https://bibliotekanauki.pl/articles/2200713.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    UWOC
    underwater channel
    oceanic medium
    optical signals
    absorption
    scattering
    attenuation
    turbulence
    Opis:
    Underwater Wireless Optical Communication (UWOC) offers significant research prospective with major challenges in the design and implementation. UWOC is capable of providing high rate of data transmission across large distances. This paper attempts to focus on the intricacies of practical implementations and open research issues of UWOC systems. Critical advances and progresses made in the field, modelling techniques and link design challenges are summarised. The purpose of this review is to give suggestions towards feasible and reliable UWOC design with improved performance. Finally the major points are summarized so that it will assist the future research in UWOC.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 4; 815--823
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of small uav position and attitude with reliable in-flight initial alignment for MEMS inertial sensors
    Autorzy:
    Wang, D.
    Dong, Y.
    Li, Q.
    Wu, J.
    Wen, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/221716.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    MEMS
    INS
    GNSS
    in-flight alignment
    unmanned aerial vehicle
    Opis:
    The advance of MEMS-based inertial sensors successfully expands their applications to small unmanned aerial vehicles (UAV), thus resulting in the challenge of reliable and accurate in-flight alignment for air-borne MEMS-based inertial navigation system (INS). In order to strengthen the rapid response capability for UAVs, this paper proposes a robust in-flight alignment scheme for airborne MEMS-INS aided by global navigation satellite system (GNSS). Aggravated by noisy MEMS sensors and complicated flight dynamics, a rotation-vector-based attitude determination method is devised to tackle the in-flight coarse alignment problem, and the technique of innovation-based robust Kalman filtering is used to handle the adverse impacts of measurement outliers in GNSS solutions. The results of flight test have indicated that the proposed alignment approach can accomplish accurate and reliable in-flight alignment in cases of measurement outliers, which has a significant performance improvement compared with its traditional counterparts.
    Źródło:
    Metrology and Measurement Systems; 2018, 25, 3; 603-616
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Challenges in Producing Reliable Tensile Properties by SIMA 7075
    Autorzy:
    Erzi, E.
    Gursoy, O.
    Yüksel, Ç.O.K.
    Kirtay, S.
    Dispinar, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/380843.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    AA7075
    mechanical properties
    product development
    semi-solid processing
    thixocasting
    SIMA
    właściwości mechaniczne
    rozwój produktu
    przetwarzanie
    Opis:
    Aluminium alloys are one of the preferred materials especially for land and air transportation because of their high strength and low-density properties. Although production using casting method is economical yet it has some disadvantages. Shrinkage which is occurred due to the density difference between the solid and liquid metal is prevented by feeders which need to be calculated. Liquid metal should be transferred to the mould without any turbulence. As a result, sprues are needed to be designed precisely. On the other hand, aluminium alloys can also be shaped by forging at semi-solid temperatures. There are some advantages compared to the traditional forging methods of improving die life due to the lower tonnage values. In this study, semi-solid produced 7075 aluminium alloy die filling capabilities were investigated. To achieve semisolid structure strain induced melt activated method (SIMA) was used. The desired structure was achieved at 635°C and 30 minutes of duration of heat treatment. After determining the optimum parameters, metallographic analysis, density calculations, porosity distribution and tensile tests were carried out. It was found that the reproducibility of SIMA produced 7075 alloy was quite low. A proper tensile test result was achieved only 7 of the total 15 tests and the mean value was 386 MPa. The main reason for this scattered in mechanical properties could be the chemical composition of the alloy and the rapid solidification of the liquid eutectic phases. It is important to define the best fitting process parameters and controlling them precisely will be the most important factors for future studies.
    Źródło:
    Archives of Foundry Engineering; 2018, 18, 3; 71-75
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development of rapid and reliable cuckoo search algorithm for global maximum power point tracking of solar PV systems in partial shading condition
    Autorzy:
    Bentata, Khadidja
    Mohammedi, Ahmed
    Benslimane, Tarak
    Powiązania:
    https://bibliotekanauki.pl/articles/1845531.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    photovoltaic system
    maximum power point tracking
    partial shading
    cuckoo search algorithm
    Opis:
    The solar photovoltaic output power fluctuates according to solar irradiation, temperature, and load impedance variations. Due to the operating point fluctuations, extracting maximum power from the PV generator, already having a low power conversion ratio, becomes very complicated. To reach a maximum power operating point, a maximum power point tracking technique (MPPT) should be used. Under partial shading condition, the nonlinear PV output power curve contains multiple maximum power points with only one global maximum power point (GMPP). Consequently, identifying this global maximum power point is a difficult task and one of the biggest challenges of partially shaded PV systems. The conventional MPPT techniques can easily be trapped in a local maximum instead of detecting the global one. The artificial neural network techniques used to track the GMPP have a major drawback of using huge amount of data covering all operating points of PV system, including different uniform and non-uniform irradiance cases, different temperatures and load impedances. The biological intelligence techniques used to track GMPP, such as grey wolf algorithm and cuckoo search algorithm (CSA), have two main drawbacks; to be trapped in a local MPP if they have not been well tuned and the precision-transient tracking time complex paradox. To deal with these drawbacks, a Distributive Cuckoo Search Algorithm (DCSA) is developed, in this paper, as GMPP tracking technique. Simulation results of the system for different partial shading patterns demonstrated the high precision and rapidity, besides the good reliability of the proposed DCSA- GMPPT technique, compared to the conventional CSA-GMPPT.
    Źródło:
    Archives of Control Sciences; 2021, 31, 3; 495-526
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development of rapid and reliable cuckoo search algorithm for global maximum power point tracking of solar PV systems in partial shading condition
    Autorzy:
    Bentata, Khadidja
    Mohammedi, Ahmed
    Benslimane, Tarak
    Powiązania:
    https://bibliotekanauki.pl/articles/1845518.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    photovoltaic system
    maximum power point tracking
    partial shading
    cuckoo search algorithm
    Opis:
    The solar photovoltaic output power fluctuates according to solar irradiation, temperature, and load impedance variations. Due to the operating point fluctuations, extracting maximum power from the PV generator, already having a low power conversion ratio, becomes very complicated. To reach a maximum power operating point, a maximum power point tracking technique (MPPT) should be used. Under partial shading condition, the nonlinear PV output power curve contains multiple maximum power points with only one global maximum power point (GMPP). Consequently, identifying this global maximum power point is a difficult task and one of the biggest challenges of partially shaded PV systems. The conventional MPPT techniques can easily be trapped in a local maximum instead of detecting the global one. The artificial neural network techniques used to track the GMPP have a major drawback of using huge amount of data covering all operating points of PV system, including different uniform and non-uniform irradiance cases, different temperatures and load impedances. The biological intelligence techniques used to track GMPP, such as grey wolf algorithm and cuckoo search algorithm (CSA), have two main drawbacks; to be trapped in a local MPP if they have not been well tuned and the precision-transient tracking time complex paradox. To deal with these drawbacks, a Distributive Cuckoo Search Algorithm (DCSA) is developed, in this paper, as GMPP tracking technique. Simulation results of the system for different partial shading patterns demonstrated the high precision and rapidity, besides the good reliability of the proposed DCSA-GMPPT technique, compared to the conventional CSA-GMPPT.
    Źródło:
    Archives of Control Sciences; 2021, 31, 3; 495-526
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reliable crack width prediction in EN 13084 & CICIND
    Autorzy:
    Noakowski, P.
    Harling, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/231265.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    projekt zawansowany
    konstrukcja żelbetowa
    szerokość pęknięcia
    bezpieczeństwo
    szczelność
    trwałość
    zbrojenie minimalne
    analiza nieliniowa
    advanced design
    reinforced concrete structure
    crack width
    safety
    tightness
    durability
    minimum reinforcement
    non-linear analysis
    Opis:
    Cracks in concrete are inevitable but fortunately cracking enables the structures to get rid of its bending moment peaks. The reduction is due to the redistribution of the load induced moments and cut of the temperature-imposed moments. However, cracking becomes completely harmless if the crack widths are controlled properly by reinforcement. In this regard a method for crack width prediction is presented in this paper which thanks its reliability is widely accepted in the standards EN 13084, CICIND and DIN 1056.
    Źródło:
    Archives of Civil Engineering; 2020, 66, 1; 3-23
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sn-Pd-Ni Electroplating on Bi2Te3-Based Thermoelectric Elements for Direct Thermocompression Bonding and Creation of a Reliable Bonding Interface
    Autorzy:
    Kang, Seok Jun
    Bae, Sung Hwa
    Son, Injoon
    Powiązania:
    https://bibliotekanauki.pl/articles/2049169.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    tin electroplating
    thermoelectric module
    thermocompression bonding
    Bi2Te3
    direct bonding
    Opis:
    The Sn-Ag-Cu-based solder paste screen-printing method has primarily been used to fabricate Bi2Te3-based thermoelectric (TE) modules, as Sn-based solder alloys have a low melting temperature (approximately 220°C) and good wettability with Cu electrodes. However, this process may result in uneven solder thickness when the printing pressure is not constant. Therefore, we suggested a novel direct-bonding method between the Bi2Te3-based TE elements and the Cu electrode by electroplating a 100 μm Sn/ 1.3 μm Pd/ 3.5 μm Ni bonding layer onto the Bi2Te3-based TE elements. It was determined that there is a problem with the amount of precipitation and composition depending on the pH change, and that the results may vary depending on the composition of Pd. Thus, double plating layers were formed, Ni/Pd, which were widely commercialized. The Sn/Pd/Ni electroplating was highly reliable, resulting in a bonding strength of 8 MPa between the thermoelectric and Cu electrode components, while the Pd and Ni electroplated layer acted as a diffusion barrier between the Sn layer and the Bi2Te3 TE. This process of electroplating Sn/Pd/Ni onto the Bi2Te3 TE elements presents a novel method for the fabrication of TE modules without using the conventional Sn-alloy-paste screen-printing method.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 4; 963-966
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A lag in the advancement of biotechnology; reliable control of maize stem borers in Africa
    Autorzy:
    Samuel, A.O.
    Tabbassum, B.
    Sharif, M.N.
    Bhatti, M.U.
    Nasir, I.A.
    Husnain, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/65339.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    climate change
    food security
    integrated pest management
    pest management
    pest control
    maize
    stem
    borer
    RNAi technology
    Opis:
    The future of food security in Africa is being severely threatened due to an exponential increase in population, which is almost three times the increase of food production. Maize production is constrained by stem borers which cause significant yield losses. Yield losses can be further compounded by higher temperatures due to climate changes, which are expected to increase the population of maize stem borers. While several methods have been employed in stem borer management, there is still significant damage caused by maize stem borers. This necessitates better control methods including the adoption of recent biotechnological advancement in RNA interference (RNAi) technology. This review highlights evidence of an increase in the stem borer population as well as the foreseen decline in maize production worldwide due to the effects of climatic changes. Furthermore, we have drawn attention to improved methods that have been used to control stem borers in maize production as well as a reluctant acceptance of traditional biotechnology in Africa. Finally, we suggest the application of alternative RNA interference techniques to breed maize for efficient pest control in order to achieve food security, improve nutrition and promote sustainable maize production.
    Źródło:
    Journal of Plant Protection Research; 2018, 58, 1
    1427-4345
    Pojawia się w:
    Journal of Plant Protection Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dokładniej, rzetelniej, taniej. Badania oparte na rejestrach publicznych jako szansa dla badań społecznych w Polsce
    Accurate, Reliable and Cheap. Register-based Analysis as an Opportunity for Social Research in Poland
    Autorzy:
    Jasiński, Mikołaj
    Bożykowski, Marek
    Zając, Tomasz
    Styczeń, Marek
    Izdebski, Albert
    Powiązania:
    https://bibliotekanauki.pl/articles/427587.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    metodologia badań statystycznych
    badania losów absolwentów
    rynek pracy
    rejestr administracyjny
    Zakład Ubezpieczeń Społecznych
    statistical methodology
    research on graduates
    labour market
    administrative register
    Social Insurance Institution
    Opis:
    Badania społeczne dotyczące różnorodnych zjawisk (między innymi z zakresu procesów edukacyjnych, rynku pracy, demografii, migracji, epidemiologii) mogą być prowadzone na podstawie informacji z rejestrów administracyjnych. Znajomość potencjału oraz ograniczeń tego podejścia stwarza możliwość pogodzenia pozornie sprzecznych postulatów – prowadzenia tanich, a jednocześnie efektywnych badań złożonych zjawisk społecznych. Korzystanie z informacji z rejestrów może pomóc rozwiązać szereg metodologicznych problemów, takich jak malejący poziom realizacji sondażowych badań reprezentacyjnych, nierzetelność zbieranych informacji itp. Celem artykułu jest prezentacja specyfiki metodologii badań statystycznych wykorzystujących informacje z rejestrów. Jest to jeden z efektów projektu badawczego zrealizowanego przez Autorów. Rozważania metodologiczne uzupełniają przykładowe wyniki badań ścieżek edukacyjnych studentów oraz historii zatrudnienia absolwentów Uniwersytetu Warszawskiego z wykorzystaniem danych z rejestrów uczelni i Zakładu Ubezpieczeń Społecznych, przeprowadzonych w ramach projektu. Autorzy wyjaśniają również problemy technologiczne, administracyjne oraz organizacyjne, których przezwyciężenie jest warunkiem prowadzenia badań wykorzystujących informacje z rejestrów. Wnioski metodologiczne przedstawione w artykule rozwijają propozycje badaczy skandynawskich najbardziej doświadczonych w dziedzinie badań wykorzystujących informacje z rejestrów administracyjnych.
    A social research project concerning various social issues (including education, labour market, demography, migration, epidemiology) can be conducted with register-based analysis. The knowledge about the potential and limits of this approach allows to reconcile the seemingly contradictory features of the study of complex social phenomena: effectiveness and low cost. Register-based analysis can solve a number of methodological problems, such as a decreasing response rate and a low reliability of data. The paper presents the methodology of register-based analysis. The experiences gathered during the research project conducted by the authors allowed to improve the above mentioned methodology. The methodological reflections are complemented with the results of research on educational and professional careers of the University of Warsaw graduates, based on the registers of UW and Social Insurance Institution. In addition, the authors present selected technological, administrative, and organisational problems that need to be answered in order to conduct register-based research. The methodological conclusions of the paper develop the work of Scandinavian researchers who are the most experienced scientists in the field of register-based analysis.
    Źródło:
    Studia Socjologiczne; 2015, 1(216); 45-72
    0039-3371
    Pojawia się w:
    Studia Socjologiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A reliable method of completing and compensating the results of measurements of flow parameters in a network of headings
    O pewnej metodzie uzupełniania i wyrównywania wyników pomiarów parametrów przepływu w sieci wyrobisk górniczych
    Autorzy:
    Dziurzyński, W.
    Krach, A.
    Pałka, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/220068.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    measurements in headings
    database
    forecasting the ventilation process
    safety of the mine ventilation system
    pomiary w wyrobiskach
    baza danych
    prognozowanie procesu przewietrzania
    bezpieczeństwo systemu wentylacji kopalni
    Opis:
    Forecasting a ventilation process is based on two factors: using a validated software (Dziurzyński et al., 2011; Pritchard, 2010) and a properly prepared database encompassing the parameters describing the flow of air and gases, compatible with the adopted mathematical model of the VentGraph software (Dziurzyński, 2002). With a body of measurement data and a mathematical model for computer calculations and air flow simulation at our disposal, we proceed to develop a numerical model for a chosen network of mine headings. Preparing a numerical model of a ventilation network of a given mine requires providing a collection of data regarding the structure of the network and the physical properties of its elements, such as headings, fans, or stoppings. In the case of fire simulations, it is also necessary to specify the parameters describing the seat of a fire and the properties of the rocks of which the rock mass is comprised. The methods which are currently applied to this task involve manual ventilation measurements performed in headings; the results obtained in the course of these measurements constitute a basis for determining physical parameters, such as the aerodynamic resistance of a heading, density of the flow of air, or natural depression. Experience shows that – due to difficulties regarding accessibility of headings, as well as the considerable lengths of the latter – there are some nodes and headings in mines where such measurements are not performed. Thus, an attempt was made to develop a new methodology that would provide the missing data on the basis of some other available information concerning – for example – the air density, the geometry of headings and elevations. The adopted methodology suggests that one should start with balancing the air mass fluxes within the structure of a network of headings. The next step is to compile a database concerning the pressure values in the network nodes, based on the measurement results – and provide the missing pressure values on the basis of the available results of measurements carried out in adjacent nodes, as well as the pressure value calculated on the basis of the heading geometry and the given volumetric flow rate. The present paper discusses the methodology of compensating and balancing the volumetric air flow rates within a network of headings (Chapter 2) and the methodology of determining pressure values (Chapter 3) in the nodes of the network. The developed calculation algorithms – verified by means of sample calculations performed for a selected area of a mine ventilation network – were introduced into the VentGraph software system. The calculation results were presented in tabular form. The Summary section discusses the minuses and pluses of the adopted methodology.
    Podstawą prognozy procesu przewietrzania jest posługiwanie się zwalidowanym programem komputerowym (Dziurzyński i in., 2011; Pritchard, 2010) oraz poprawnie przygotowaną bazą danych zawierającą parametry opisujące przepływ powietrza i gazów, zgodną z przyjętym modelem matematycznym w programie komputerowym VentGraph (Dziurzyński, 2002). Dysponując bazą danych pomiarowych oraz przyjętym do obliczeń komputerowych i symulacji procesu przewietrzania modelem matematycznym przystępujemy do opracowania modelu numerycznego dla wybranej sieci wyrobisk kopalni. Przygotowanie modelu numerycznego sieci wentylacyjnej danej kopalni wymaga dostarczenia zestawu danych dotyczących struktury sieci i własności fizycznych jej elementów, tj. wyrobisk, wentylatorów, tam, a przy symulacji pożaru dodatkowo wymagane jest podanie parametrów opisujących ognisko pożaru oraz własności skał górotworu. Obecna praktyka postępowania polega na tym, że wykonuje się ręczne pomiary wentylacyjne w wyrobiskach górniczych, a uzyskane wyniki stanowią podstawę do wyznaczenia parametrów fizycznych takich jak: opór aerodynamiczny wyrobiska, gęstość przepływającego powietrza i naturalna depresja. Z uwagi na występujące trudności w dostępności wyrobisk jak również na znaczne ich długości, praktyka pokazuje, że pomiary nie są realizowane we wszystkich węzłach i wyrobiskach kopalni. Dlatego podjęto próbę opracowania nowej metodyki prowadzącej do uzupełnienia brakujących danych na podstawie innych dostępnych danych dotyczących np. gęstości powietrza, geometrii wyrobisk i kot niwelacyjnych. Z przyjętej metodyki wynika, że w pierwszej kolejności należy wykonać bilans strumieni masy powietrza w strukturze sieci wyrobisk. Następnie zbudować bazę danych ciśnień w węzłach sieci w oparciu o pomiary i uzupełnić brakujące ciśnienia na podstawie dostępnych wyników pomiarów w sąsiednich węzłach oraz ciśnienia obliczonego z wartości oporu aerodynamicznego wyznaczonego na podstawie geometrii wyrobiska i znanego strumienia objętości. W artykule przedstawiono metodykę wyrównywania i bilansowania strumieni objętości powietrza w sieci wyrobisk (rozdz. 2) oraz metodykę wyznaczania ciśnień (rozdz. 3) w węzłach sieci wyrobisk. Opracowane algorytmy obliczeń wprowadzono do systemu programów VentGraph, które zostały sprawdzone poprzez obliczenia dla przykładu wybranego rejonu kopalnianej sieci wentylacyjnej. Wyniki obliczeń przedstawiono w postaci tabelarycznej. W podsumowaniu omówiono wady i zalety przyjętej metodyki.
    Źródło:
    Archives of Mining Sciences; 2015, 60, 1; 3-24
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

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