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Tytuł:
Diagnostics the natural frequencies of the automobile disc and their analysis
Autorzy:
Vavro, J.
Kopecky, M.
Saga, M.
Powiązania:
https://bibliotekanauki.pl/articles/327416.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
diagnostics
frequency
experimental measurement
shape of disc
Opis:
The article deals with the analysis of the natural discs frequencies realized by the means of mathematic simulation by the finite elements method, by which the programs AutoCAD and Cosmos M were used. First fifty natural frequencies are presented for the listed type of the steel disc. The experimental measurement for the listed disc type was made by the Doppler vibrometer. The results of the measurement are presented in a graphic form and the measurement was performed in radial and axial direction.
Źródło:
Diagnostyka; 2004, 30, T. 2; 165-168
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in aerodynamic parameters for 5-stage steam turbine during warming and gradual start-up to nominal operating parameters
Autorzy:
Hoznedl, M.
Bednář, L.
Tajč, L.
Powiązania:
https://bibliotekanauki.pl/articles/175267.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam turbine
experimental measurement
warming
start-up
efficiency
Opis:
The results of experiments on the 5-stage steam turbine are presented. The parameters of individual stages as well as the whole turbine are observed during the gradual start-up to nominal operating parameters. The pressures and temperatures are shown at stages in idling, heating up the experimental turbine and during the transition to operating speed. A greater attention is devoted to three selected operational conditions with different processed enthalpy drops. Problems with efficiency and enthalpy drops measurement during warming are described. The attempts to measure flow parameters quickly and without time for heating of turbine casings and other parts are often in the experimental research caused byprice of the survey. This contributionÞs task is to inform about these situations and to avoid confused and untrue results obtained by somewhat hasty measurements due to reduction and optimisation of costs.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2016, 134; 45-62
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of a Directional Dependenceon Mechanical Properties of Composites Reinforced with Chopped Carbon Fibre Produced by Additive Manufacturing
Autorzy:
Majko, Jaroslav
Handrik, Marian
Vaško, Milan
Sága, Milan
Kopas, Peter
Dorčiak, Filip
Sapietová, Alžbeta
Powiązania:
https://bibliotekanauki.pl/articles/27313864.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
experimental measurement
physical properties
3D printing
composite
fibre reinforcement
MATLAB
Opis:
Progress in the industry is accompanied by the development of new materials and more efficient technological production processes. At present, additive production is becoming very attractive in all industries (research, development, production), which brings a number of advantages compared to subtractive methods (customization, production speed, control of material properties by users, etc.). The main advantage of 3D printing is the controlled deposition of material in defined places. Instead of demanding manual labour, fully automated production via computers leads to the manufacturing of complex components from materials whose production in conventional ways would be problematic or even impossible. Because these are new technologies, the main direction of research at present is to identify the basic physical properties of these materials under different types of loading. The main goal of this article is to observe the dependence of the behaviour of the extruded material (thermoplastic reinforced with chopped carbon fibre) on the printing parameters (thickness of the lamina, the orientation of the fibres of the printed material, etc.). Based on published scientific works, it appears that these settings have a significant impact on the achieved physical properties. This is the reason why the authors decided to analyze the influence of these parameters on the basis of processed data from experimental measurements of mechanical properties in the MATLAB program. As this is FFF printing, an essential condition is to identify and specify the directional dependence of the behavior of the printed material. This physical phenomenon is a necessary condition for gradual knowledge for the purposes of a subsequent mathematical description of the material properties. According to the authors, for the purposes of modeling these materials in FEM-based programs, it is essential to define the directional dependence in the plane of the lamina.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 455--461
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Data-based method for the determination of temperature dependence of heat capacity of highly dispersed powders
Autorzy:
Karnina, A.
Gyrenko, A.
Klymenko, A.
Mysov, O.
Powiązania:
https://bibliotekanauki.pl/articles/411297.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
highly dispersed powder
heat capacity
equations
experimental measurement
uncertainty of measurements
Opis:
Accuracy of engineering and economic calculations in different areas requires the use of accurate and prompt values of heat capacity for new or modified materials. A number of existing methods have an error in measuring the heat capacity of powder materials, and use non-standard devices and electric heaters which are not produced industrially. This work is aimed at developing the method for determining the heat capacity of the powder, accuracy evaluation of this method and mathematical processing of experimental data to determine the temperature dependence of the molar heat capacity. To solve the problem the method based on the DTA technique was developed. The measuring apparatus for determining the temperature dependence of the heat capacity includes two standard cups for DTA analysis with investigated material and MgO, heat-variable resistor of film type Pt100, multichannel recorder. The apparatus is placed in a drying oven. From the theory of heat transfer and the assumption about steady-flow heat transfer the equation for molar heat capacity was obtained. The method requires the measuring of temperature of the investigated material and MgO during the linear heat of the drying oven as well as air temperature in the oven. Empirical values of heat capacity of standard substances calculated by the equation for each temperature were compared with the values from reference data. The uncertainty of finding the heat capacity did not exceed 0,5%.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2015, 4, 4; 23-28
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydraulic transients analysis in pipe networks by the method of characteristics (MOC)
Autorzy:
Wichowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/240954.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
hydraulic transients
method of characteristics
single pipe
experimental measurement
pipe networks
numerical simulations
Opis:
The paper presents results of an experimental and theoretical study of the hydraulic transients in straight pipes and numerical simulations of unsteady flow in pipe networks. A mathematical model consists of a set of partial differential equations of hyperbolic type, which have been transformed by the method of characteristics into ordinary differential equations which are solved by the predictor-corrector method. Experimental tests have been performed, in order to examine the hydraulic transients phenomenon, in a single straight steel pipe. The experiments were carried out in the hydraulic laboratory of the Institute of Water Supply and Water Engineering, Environmental Engineering Faculty, Warsaw University of Technology. The numerical results show that the presented one dimensional model for a single pipe correctly describes the phenomenon since there is a good agreement with experimental maximum and minimum oscillations. In the paper, selected exemplary equations in a difference form for the pipe networks are also presented. One calculation example is given relating to the complex water-pipe network consisting of 17 loops, 48 pipelines and 33 nodes, supplied by two independent sources. Water-hammer throughout the whole pipeline network was caused by closing the gate valve at mid-point of one selected pipe. The results of the numerical calculations are presented in graphic form with respect to the final cross-sections of pipes.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 3; 267-291
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Axial stiffness for large-scale ball slewing rings with four-point contact
Autorzy:
Hrcek, Slavomir
Kohar, Robert
Steininger, Jan
Powiązania:
https://bibliotekanauki.pl/articles/2090718.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stiffness
experimental measurement
slewing ring
deformation constant
sztywność
pomiar eksperymentalny
pierścień obrotowy
stała deformacji
Opis:
This article deals with the design of slewing rings (slewing bearings). A fully parametric, 3D virtual model of a ball slewing ring with four-point contact was created in the PTC/Creo Parametric CAD system. This model was subsequently used for finite-element analysis using Ansys/Workbench CAE software. The purpose of the FEM analysis was to determine the axial stiffness characteristics. Results of FEM analysis were experimentally verified using a test bench. At the end of the article, we present the nomograms of the deformation constant for different pitch diameters, rolling element diameters and contact angles.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; e136725, 1--11
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Axial stiffness for large-scale ball slewing rings with four-point contact
Autorzy:
Hrcek, Slavomir
Kohar, Robert
Steininger, Jan
Powiązania:
https://bibliotekanauki.pl/articles/2173594.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stiffness
experimental measurement
slewing ring
deformation constant
sztywność
pomiar eksperymentalny
pierścień obrotowy
stała deformacji
Opis:
This article deals with the design of slewing rings (slewing bearings). A fully parametric, 3D virtual model of a ball slewing ring with four-point contact was created in the PTC/Creo Parametric CAD system. This model was subsequently used for finite-element analysis using Ansys/Workbench CAE software. The purpose of the FEM analysis was to determine the axial stiffness characteristics. Results of FEM analysis were experimentally verified using a test bench. At the end of the article, we present the nomograms of the deformation constant for different pitch diameters, rolling element diameters and contact angles.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; art. no. e136725
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the transformation of long gravity waves on a sloping beach
Autorzy:
Szmidt, J.K.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/49151.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
long wave
gravity wave
transformation
wave transformation
sloping beach
wave gauge
propagation
investigation
experimental measurement
Opis:
The transformation of long water waves arriving at a sloping beach is investigated. An approximate theory is presented for plane periodic waves propagating in water of non-uniform depth. The theoretical description of the phenomenon, based on certain kinematic assumptions, is formulated in the material variables, and the solution is constructed by applying the Hamilton variational principle. In order to assess the accuracy of the formulation and to learn more about long wave transformation, experimental measurements were carried out in a laboratory flume. In the experiments, a water wave, generated by a piston-type wave maker placed at one end of the flume, propagated towards a rigid inclined ramp installed at the other end of the flume. The wave transformation along the direction of its propagation was recorded by a set of wave gauges installed along the flume. The wave run- up on the sloping beach was measured with a special conductivity gauge placed alongside the ramp. Comparison of the theoretical results with experimental data indicates that the proposed theoretical formulation provides a good description of the main features of wave transformation behaviour over a sloping beach, except in the vicinity of the shore point, where some discrepancies occur.
Źródło:
Oceanologia; 2010, 52, 3; 363-389
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The process of aluminium moduls warming in the car industry
Autorzy:
Mlýnek, J.
Srb, R.
Powiązania:
https://bibliotekanauki.pl/articles/384339.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
intensity of heat radiation
experimental measurement of radiation intensity
interpolation in multidimensional space
software implementation
Opis:
This paper concerns the heating of aluminium moulds in the car industry. The moulds are intended for the production of artificial leathers. The mould is sprinkled with a special powder and is subsequently warmed by infra heaters located above the mould. It is necessary to ensure approximately the same heat intensity radiation on the surface mould, and in this way, the same material structure and colour of the artificial leather. The mould surface is described by its elementary surfaces. A producer uses moulds of different sizes and they are often very rugged. We must keep track of possible collisions of heater locations. We have used a genetic algorithm to optimize heater locations for a given mould. In this article, we will focus on the calculation procedure of thermal radiation intensity on the mould surface and on the determination of the average aberration of radiation intensity for particular heater locations, which is an important part of our genetic algorithm.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2012, 6, 2; 47-50
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of nearby structure on the wind flow around the cube structure
Autorzy:
Olekšáková, I.
Hubová, O.
Konečná, L.
Powiązania:
https://bibliotekanauki.pl/articles/131473.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Komisja Inżynierii Budowlanej PAN Oddział w Katowicach
Tematy:
wind tunnel
turbulent wind flow
cube structure
pressure coefficient
experimental measurement
tunel aerodynamiczny
turbulentny przepływ wiatru
współczynnik ciśnienia
pomiar eksperymentalny
Opis:
The influence of a nearby structure on the turbulent wind flow around the cube structure was investigated in this paper. This problem was solved by two different methods. The first one was the numerical solution by CFD simulations. Obtained results were compared with the results from tests made in the wind tunnel. Description of the problem, theory and basic equations, specification of the 3D simulations and experimental measurements were mentioned. From the evaluation of the results, pressure coefficients for this type of structure and for three solved cases, were determined. Pressure coefficients determined by the Eurocode were larger than the values determined by the tests and CFD simulations. In the case of self-standing cube, pressure coefficients were following: Cp=-2.35 (CFD), Cp=-2.404 (test). Deviations were relatively small. Hence, used k-ε model is suitable for determination of the maximum values of pressure coefficients Cp in the investigated case.
Źródło:
Roczniki Inżynierii Budowlanej; 2015, 15; 29-35
1505-8425
Pojawia się w:
Roczniki Inżynierii Budowlanej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eksperymentalne techniki pomiaru wyobraźni wizualnej i twórczej – potencjał aplikacyjny w badaniach pedagogicznych
Experimental Techniques of Measuring Visual and Creative Imagination– Application Potential in Pedagogical Research
Autorzy:
Jankowska, Dorota Maria
Powiązania:
https://bibliotekanauki.pl/articles/2140784.pdf
Data publikacji:
2018-06-30
Wydawca:
Wydawnictwo Naukowe Dolnośląskiej Szkoły Wyższej
Tematy:
wyobraźni twórcza
wyobraźnia wizualna
pomiar wyobraźni
eksperymentalnetechniki pomiaru
creative imagination
visual imagination
imagination measurement
experimental techniquesof measurement
Opis:
W artykule przedstawiony został przegląd badań diagnostycznych mierzących wyobraźnię wizualną i twórczą, wykorzystywanych przez psychologów. Szczególną uwagę poświęcono technikompomiaru opracowanym w ramach współczesnych teorii procesu twórczego. Przeanalizowano teoretyczne założenia tych technik, procedury badania oraz czynniki wpływające na trafność i rzetelnośćpomiaru zdolności wyobrażeniowych. Wnioski płynące z tej analizy były podstawą określenia możliwości zastosowania eksperymentalnych technik pomiaru wyobraźni twórczej w badaniach pedagogicznych, zwłaszcza w diagnostyce potencjału twórczego dzieci.
This paper aims to present an overview of diagnostic tasks measuring creative imagination, appliedby psychologists in experimental studies. A special attention is given to experimental techniques formulated within the framework of major theories of creative process. The article examines theoretical assumptions of these techniques, procedures of the study and factors which influence the validity and reliability of measuring imagery abilities. The conclusions drawn from this examination provide a basis fordefining a possibility of applying experimental techniques of creative imagination measurement in educational studies, especially in the diagnostics of children’s creative potential.
Źródło:
Teraźniejszość – Człowiek – Edukacja; 2018, 21, 2(82); 103-124
1505-8808
2450-3428
Pojawia się w:
Teraźniejszość – Człowiek – Edukacja
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of Forces During the Extraction Process
Autorzy:
Biały, W.
Wedzicha, J.
Nordin, V.
Powiązania:
https://bibliotekanauki.pl/articles/2065025.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
workability
device
component forces
experimental research
measurement
Opis:
The article briefly describes the factors affecting the workability of coal seams. Next, the construction and principle of operation of a globally unique device for determining the values of forces involved in the cutting process (coal extraction) named POU-BW/01-WAP by the author were presented. It is the only device in the world that determines two of the three component forces that are involved in the cutting process. To this end, two independent measuring blocks were used, which consist of tensometric force sensors: cutting (Fs) and pick downforce (Fd). To register these forces, a real pick was used, which is used in longwall drum shearers - a conical pick. The device has ATEX certification that allows working in real conditions, as a device intended for use in potentially explosive atmospheres - in accordance with Directive 94/9/EC. The instrument has received many awards at global inventiveness and innovative solution trade shows.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2018, 1, 1; 117--128
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of thermocouple time constants as a function of fluid velocity
Autorzy:
Majdak, M.
Jaremkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/114056.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
time constant
thermocouple
transient temperature measurement
experimental analysis
Opis:
In steady-state conditions when the fluid temperature is constant, there is no damping and time lag so the temperature measurement can be performed with a high accuracy. But when the fluid temperature is varying rapidly as during the start-up, quite appreciable differences occur between the exact and measured temperature because of the time required for the transfer of heat to the thermocouple placed inside a thermometer pocket. The temperature of the fluid is one of the key parameters affecting the proper operation of thermodynamic cycles, so the precise determination of its value is very important. The speed of the response of control systems to a temperature change is closely related to the time constant of the used thermocouples. The paper presents a significant impact of fluid velocity changes (in this case air) on the value of time constants of thermometers. For this purpose, the experimental study was carried out using sheathed thermometers with different diameters and hot junctions. The time constants determined for various thermometers are compared.
Źródło:
Measurement Automation Monitoring; 2016, 62, 9; 284-287
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Separation of isochromatics and isoclinics phasemaps for the photoelastic technique with use phase shifting and a large number of high precision images
Autorzy:
Magalhaes, C. A.
Neto, P. S.
Magalhaes Jr P. A., A.
de Barcellos, C. S.
Powiązania:
https://bibliotekanauki.pl/articles/220820.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
photoelasticity
metrology
stress analysis
strain measurement
optical measurement systems
optical interferometry
experimental techniques
Opis:
Digital photoelasticity is an important optical metrology follow-up for stress and strain analysis using full-field digital photographic images. Advances in digital image processing, data acquisition, procedures for pattern recognition and storage capacity enable the use of the computer-aided technique in automation and facilitate improvement of the digital photoelastic technique. The objective of this research is to find new equations for a novel phase-shifting method in digital photoelasticity. Some innovations are proposed. In terms of phaseshifting, only the analyzer is rotated, and the other equations are deduced by applying a new numerical technique instead of the usual algebraic techniques. This approach can be used to calculate a larger sequence of images. Each image represents a pattern and a measurement of the stresses present in the object. A decrease in the mean errors was obtained by increasing the number of observations. A reduction in the difference between the theoretical and experimental values of stresses was obtained by increasing the number of images in the equations for calculating phase. Every photographic image has errors and random noise, but the uncertainties due to these effects can be reduced with a larger number of observations. The proposed method with many images and high accuracy is a good alternative to the photoelastic techniques.
Źródło:
Metrology and Measurement Systems; 2013, 20, 1; 127-138
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of experimental research on the durability and reliability of mining equipment
Autorzy:
Biały, W.
Powiązania:
https://bibliotekanauki.pl/articles/359457.pdf
Data publikacji:
2013
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
maintenance
reliability
methods of measurement
experimental research
measuring device
Opis:
Due to special conditions of functioning of machinery and devices used in coal mining, the process of its selection is important and should comprise variability of working conditions. A short review of methods of assessment of coal workability used as yet was done and the results were divided into groups. Significance of measurements and assessment of mechanical characteristics (including workability) is proven by worldwide in scientific centres by numerous elaborated methods of its assessment. In the article new devices used in determining and assessing mechanical characteristics of coal that significantly influence durability and reliability of mining machinery were described.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2013, 34 (106); 27-34
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of true stress in engineering materials using optical deformation measurement methods
Autorzy:
Bogusz, P.
Popławski, A.
Morka, A.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241743.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
true stress
optical deformation measurement
experimental studies
FEM
steel
Opis:
The aim of the paper is to evaluate a method of determining true stress in the steel sample subjected to static axial tensile on a universal testing machine. The tensile specimens were made of steel ST3, which was chosen because of its relatively high plastic deformations. Strain measurement was performed using traditional extensometers and additionally a non-contact optical deformation measuring system. Material properties were obtain by the extensometer measurements. The optical equipment registered the investigated sample through the optical system composed of two cameras and calculated a three-dimensional model of the material deformation in time. Displacement fields in axial and radial directions were determined with Digital Image Correlation method (DIC). Then the logarithmic axial strain map and radius shrinkage map in the area of the neck were obtained. Characteristic dimensions of the neck: curvature and width were also measured. It allowed determination of cross-section area changes in the real time, and in the result, calculation of actual true stress in the material during failure process. In this case Bridgman's and other scientists' formulas of stress distribution in the neck were applied. A numerical model, where material properties of finite elements were described by the Johnson-Cooke material model, was developed in LS-PrePost software. The FEM model was computed in LS-DYNA solver. The output tensile curve and neck curvature radius were compared with relevant data obtained from the optical measuring system.
Źródło:
Journal of KONES; 2012, 19, 4; 53-64
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Innovative solutions applied in tools for determining coal mechanical proprerties
Innowacyjne rozwiązania zastosowane w narzędziach do wyznaczania właściwości mechanicznych węgla
Autorzy:
Biały, W.
Powiązania:
https://bibliotekanauki.pl/articles/1205739.pdf
Data publikacji:
2015
Wydawca:
STE GROUP
Tematy:
workability
measurement instruments
measurement methods
experimental research
urabialność
urządzenia pomiarowe
metody pomiaru
badania eksperymentalne
Opis:
Due to very specific conditions of work of machines and equipment used in coal mining industry, the manner of their selection, taking into account the changing working conditions, is very important. Appropriate selection influences the increased durability and reliability of machines and equipment, which translates into the economic effects achieved. As the issue of measurement and evaluation of coal mechanical properties (including coal workability measurement) is of great importance, previously applied methods for coal workability evaluation have been shortly reviewed. The importance of the problem is confirmed by the number of methods developed in various research centers all over the world. The article presents new instruments for determining and evaluating the mechanical properties of coal material (workability). The instruments have been developed in Poland and the author of this article is their co-inventor. The construction, principle of operation and innovative character of solutions applied in the instruments have been presented.
Ze względu na bardzo specyficzne warunki pracy maszyn i urządzeń stosowanych w górnictwie węglowym, istotny jest sposób ich doboru, uwzględniający zmieniające się w trakcie pracy warunki. Prawidłowy dobór, wpływa na zwiększenie trwałości i niezawodności maszyn i urządzeń, co przekłada się na uzyskiwane efekty ekonomiczne. Z uwagi na ważność zagadnienia, jakim jest pomiar i ocena właściwości mechanicznych węgla (w tym pomiar urabialności węgla), dokonano krótkiego przeglądu dotychczas stosowanych metod oceny urabialności węgla na świecie. Istotę problemu potwierdza ilość opracowanych metod w różnych ośrodkach naukowych na świecie. W artykule opisano nowe, powstałe w Polsce przyrządy do wyznaczania i oceny właściwości mechanicznych materiału węglowego (urabialności), których autor niniejszego artykułu jest współtwórcą. Przedstawiono ich budowę, zasadę działania oraz innowacyjność zastosowanych rozwiązań.
Źródło:
Management Systems in Production Engineering; 2015, 4 (20); 202-209
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Split Hopkinson Pressure Bar impulse experimental measurement with numerical validation
Autorzy:
Baranowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/221627.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Split-Hopkinson Pressure Bar
impulse measurement
experimental testing
numerical studies
Opis:
Materials and their development process are highly dependent on proper experimental testing under wide range of loading within which high-strain rate conditions play a very significant role. For such dynamic loading Split Hopkinson Pressure Bar (SHPB) is widely used for investigating the dynamic behavior of various materials. The presented paper is focused on the SHPB impulse measurement process using experimental and numerical methods. One of the main problems occurring during tests are oscillations recorded by the strain gauges which adversely affect results. Thus, it is desired to obtain the peak shape in the incident bar of SHPB as “smooth” as possible without any distortions. Such impulse characteristics can be achieved using several shaping techniques, e.g. by placing a special shaper between two bars, which in fact was performed by the authors experimentally and subsequently was validated using computational methods.
Źródło:
Metrology and Measurement Systems; 2014, 21, 1; 47-58
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of roofs for diagnostic purposes
Pomiary przekryć na potrzeby diagnostyczne
Autorzy:
Deska, K.
Pawlowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/78070.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
measurement
roof
experimental research
geometrical structure
building construction
technical condition
constructional element
Opis:
This paper depicts selected methods used in measuring roofs for diagnostic purposes, as well as conclusions from experimental research about their use to date.
Artykuł przedstawia wybrane metody stosowane w pomiarach przekryć na potrzeby diagnostyczne oraz wnioski z dotychczasowych badań doświadczalnych odnośnie ich wykorzystania.
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2013, 15, 1
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Force analysis and simulation – experimental research on the measurement of cylindrical surface profiles
Autorzy:
Nozdrzykowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/135450.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
energy converter crankshafts
measurement of geometric deviations
force analysis
practical application
simulations
experimental tests
Opis:
The results of tests presented herein can have practical applications for the adjustment of rotary speed to ensure constant contact between the measuring sensor’s spindle tip and the crankshaft journal of a piston energy converter, whose roundness profile is being measured. Analytical considerations have been supported by the results of simulations as well as experimental tests. The research has also shown that an increase in rotary speed affects the obtained profile shape and the value of determined roundness deviation.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 48 (120); 37-42
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of constrained experimental designs on finite spaces for a modified Ek-optimality criterion
Autorzy:
Uciński, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/1838172.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
constrained optimum experimental design
minimal sum of largest eigenvalues
generalized simplicial decomposition
optimal measurement selection
Opis:
A simple computational algorithm is proposed for minimizing sums of largest eigenvalues of the matrix inverse over the set of all convex combinations of a finite number of nonnegative definite matrices subject to additional box constraints on the weights of those combinations. Such problems arise when experimental designs aiming at minimizing sums of largest asymptotic variances of the least-squares estimators are sought and the design region consists of finitely many support points, subject to the additional constraints that the corresponding design weights are to remain within certain limits. The underlying idea is to apply the method of outer approximations for solving the associated convex semi-infinite programming problem, which reduces to solving a sequence of finite min-max problems. A key novelty here is that solutions to the latter are found using generalized simplicial decomposition, which is a recent extension of the classical simplicial decomposition to nondifferentiable optimization. Thereby, the dimensionality of the design problem is drastically reduced. The use of the algorithm is illustrated by an example involving optimal sensor node activation in a large sensor network collecting measurements for parameter estimation of a spatiotemporal process.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 4; 659-677
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Przyrządy do wyznaczania właściwości mechanicznych węgla
The new tools for determining the mechanical properties of coal
Autorzy:
Biały, W.
Powiązania:
https://bibliotekanauki.pl/articles/113103.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
urabialność
urządzenia pomiarowe
metody pomiaru
badania eksperymentalne
workability
methods of measurement
experimental research
measuring device
Opis:
Ze względu na bardzo specyficzne warunki pracy maszyn i urządzeń stosowanych w górnictwie węglowym, istotny jest sposób ich doboru, uwzględniający zmieniające się w trakcie pracy warunki. Prawidłowy dobór, wpływa na zwiększenie trwałości i niezawodności maszyn i urządzeń, co przekłada się na uzyskiwane efekty ekonomiczne. Z uwagi na ważność zagadnienia, jakim jest pomiar i ocena właściwości mechanicznych węgla (w tym pomiar urabialności węgla), dokonano krótkiego przeglądu dotychczas stosowanych metod oceny urabialności węgla na świecie. Istotę problemu potwierdza ilość opracowanych metod w różnych ośrodkach naukowych na świecie. W artykule opisano nowe, powstałe w Polsce przyrządy do wyznaczania i oceny właściwości mechanicznych materiału węglowego (urabialności), których autor niniejszego artykułu jest współtwórcą. Przedstawiono ich budowę, zasadę działania oraz oryginalność zastosowanych rozwiązań. Godnym podkreślenia jest fakt, że opisane przyrządy na Międzynarodowych Targach Innowacji Technologicznych w Brukseli, zdobyły ZŁOTY i SREBRNY MEDAL.
The extremely specific environment of work of machines and equipment used in coal mining causes that their selection, taking into consideration the changing conditions, is a matter of great significance. Adequate selection enhances the durability and reliability of machines and equipment, which translates into the obtained economic effects. Due to the significance of coal mechanical properties measurement and evaluation (including coal workability measurement), the previously applied methods for coal workability assessment have been reviewed. The im-portance of the problem is confirmed by the number of methods developed in different research centres all over the world. The article presents new measuring devices for determining and evaluating the mechanical properties of coal material (workability), whose co-creator is the author of this article. The construction, the principle of operation and the originality of the ap-plied solutions have been described. Worth emphasising is the fact that the presented instru-ments were awarded GOLD and SILVER MEDAL at International Trade Fair For Technological Innovation in Brussels.
Źródło:
Systemy Wspomagania w Inżynierii Produkcji; 2018, 7, 1; 20-31
2391-9361
Pojawia się w:
Systemy Wspomagania w Inżynierii Produkcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The optical system for elongation measurement of highly deformable materials
Eksperymentalny system do pomiaru wydłużeń materiałów o wysokiej odkształcalności
Autorzy:
Lutowski, Z.
Marciniak, T.
Bujnowski, S.
Boroński, D.
Powiązania:
https://bibliotekanauki.pl/articles/256635.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy
Tematy:
experimental methods
machine vision
displacements measurement
high elongation measurement
highly deformable materials
metoda eksperymentalna
widzenie maszynowe
pomiar przemieszczeń
pomiar dużych odkształceń
wysoko odkształcalne materiały
Opis:
Displacement measurement in systems exploring the mechanical properties of materials may relate to different physical quantities. It is often related to the measurement of the displacement of working elements executing the load or the measurement of the elongation of the tested measurement area. From the technical point of view, the most complicated aspect to measure is the elongation of the tested measurement area, particularly for objects that have a structure that makes it difficult to mount external sensors, such as inductive, piezoelectric or laser extensometers. The “whole measurement procedure” is based on the detection of the marker’s location. Displacements of markers between adjacent frames exceeding a fixed value are treated as a rupture in the tested object. The disappearance of one of the markers from the camera’s view is treated also as the object rupture. Very good results of marker detection on transparent materials were obtained by the using a fluorescent marker and lighting it with ultraviolet light.
Pomiar przemieszczenia w systemach do badań własności mechanicznych może dotyczyć różnych wielkości fizycznych. Najczęściej związany jest z pomiarem przemieszczenia elementów roboczych realizujący obciążenie, pomiarem odległości pomiędzy uchwytami, w których mocowane są obiekty badań lub pomiarem wydłużenia ich części pomiarowej. Najbardziej skomplikowany z technicznego punktu widzenia jest pomiar wydłużenia części pomiarowej obiektów badań, w szczególności w przypadku obiektów, których budowa utrudnia mocowanie zewnętrznych czujników, takich jak np. czujniki tensometryczne, indukcyjne, laserowe lub piezoelektryczne. Proponowana metoda pomiaru opiera się na detekcji położenia znaczników. Przemieszczenia znaczników pomiędzy sąsiednimi ramkami obrazu przekraczające założoną wartość traktowane są jako zerwanie obiektu. Jako zerwanie obiektu traktowane jest również zniknięcie z pola widzenia kamery jednego ze znaczników. Bardzo dobre wyniki detekcji znacznika na materiałach transparentnych uzyskano, używając fluorescencyjnego znacznika i oświetlając go światłem ultrafioletowym.
Źródło:
Problemy Eksploatacji; 2013, 2; 7-17
1232-9312
Pojawia się w:
Problemy Eksploatacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Empirical testing of inventories applying on-board measurements of exhaust emissions at port and at sea
Autorzy:
Jahangiri, S.
Nikolova, N.
Tenekedjiev, K.
Powiązania:
https://bibliotekanauki.pl/articles/2140922.pdf
Data publikacji:
2018
Wydawca:
Fundacja Centrum Badań Socjologicznych
Tematy:
emission pollution in ports
emission inventory
on-board measurement
experimental ranking of inventory procedures
additive value functions
Opis:
We present a comprehensive case study to identify the best vessel-specific inventory family that predicts the primary emissions from an ocean-going vessel when at berth, while maneuvering and while cruising. The main purpose of the paper is to generalize the implication of the case study by advising a novel policy, which will allow different authorities to estimate the shipping emissions in a cost-effective and reliable way. The emissions rates of nitrogen oxides, sulphur oxides, carbon dioxide, carbon monoxide, hydrocarbon, and particulate matter from the main engine and from the auxiliary engines are measured for different modes of ship operations in an on-board experiment campaign. The measured total emission amounts were predicted with 13 families of emission inventories and prediction deviations have been calculated. A procedure was advised for estimating the prediction inventory deviations of the combined hourly emission amounts from the main engine plus the auxiliary engines. Each inventory family has been formalized as a six-dimensional vector of prediction deviations for any mode of operation. The best vessel-specific inventory families were identified using the minimal mean absolute deviation criteria. A more rational procedure to rank inventories is considered, which treats the missing value problem and constructs a six-attribute value function. The use of preferential analysis and value functions further clarifies the recommended choice of inventory method. In this case study we demonstrated that the most suitable inventory families will provide reliable predictions with acceptable deviations from the measured emissions. At berth and for maneuvering, the best inventory family turned out to be MOPSEA (with 32.2 % and 39.6 % mean absolute deviations respectively). For cruising, the most precise inventory family is MEET (with 59.2% mean absolute deviation), whereas MOPSEA being the third best. However, some of the other inventories produce unacceptably high deviation, well above 100%. The practical implication is that while inventory methods can produce precise and cost-effective predictions, they should never be used without experimental verification. That is why, we provide an algorithm to use on-board experimental measurements to identify the best vessel-specific inventory family, which predicts the primary emission of a ship at a given mode of operation. The proposed algorithm and the implications of the case study are utilized to motivate a proposal for a novel future policy for a cost-effective and reliable emission estimation from shipping.
Źródło:
Journal of Sustainable Development of Transport and Logistics; 2018, 3, 2; 6-33
2520-2979
Pojawia się w:
Journal of Sustainable Development of Transport and Logistics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the acoustic climate during the drilling of gas wells in post-mining areas
Autorzy:
Macuda, J.
Łukańko, Ł.
Hendel, J.
Powiązania:
https://bibliotekanauki.pl/articles/298852.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
coal mine methane
post-mining area
experimental gas well
coal gobs
noise
noise emission from rig
noise measurement
Opis:
Coal mine methane from post extraction coal gobs is most efficiently produced with drilling wells realized from the surface. In Polish conditions, such wells are most frequently drilled in highly urbanized areas and residential quarters. The drilling of such wells creates the hazard of exceeding admissible noise levels in the areas requiring acoustic protection during the day and night. Therefore it is very important to assess the level of noise emitted by the rig and to establish the isophones 45 dB and 55 dB for various field conditions. With such information, the location of the rig can be properly selected at the stage of well design. The level of noise emitted in the environment during the drilling of experimental gas well Wieczorek-AGH-1, was established on the basis of noise analyses performed within the well pad area and its closest vicinity with the reference method, described in the Regulation of the Environment Minister of 30 October 2014 concerning the requirements of the analyses of emissions and the quantity of water consumption (Official Journal of 2014, item 1542), hereinafter called the Regulation.
Źródło:
AGH Drilling, Oil, Gas; 2017, 34, 4; 917-932
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
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