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Wyszukujesz frazę "micro model" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Modelling and Simulation of the Magnesium Primary Phase Crystallization in the AZ91/SiCp Composite Dependent on Mass Fraction of SiCp
Autorzy:
Lelito, J.
Krawiec, H.
Vignal, V.
Gracz, B.
Żak, P. L.
Szucki, M.
Powiązania:
https://bibliotekanauki.pl/articles/356885.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical simulation
AZ91/SiCp composite
micro-model
Opis:
The aim of this work is to develop a numerical model capable of predicting the grain density in the Mg-based matrix phase of an AZ91/SiC composite, as a function of the total mass fraction of the embedded SiC particles. Based on earlier work in a range of alloy systems, we assume an exponential relationship between the grain density and the maximum supercooling during solidification. Analysis of data from cast samples with different thicknesses, and mass fractions of added SiCp, permits conclusions to be drawn on the role of SiCp in increasing grain density. By fitting the data, an empirical nucleation law is derived that can be used in a micro model. Numerical simulation based on the model can predict the grain density of magnesium alloys containing SiC particles, using the mass fraction of the particles as inputs. These predictions are compared with measured data.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 29-32
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methodology of Comparative Validation of Selected Foundry Simulation Codes
Autorzy:
Ignaszak, Z.
Popielarski, P.
Hajkowski, J.
Codina, E.
Powiązania:
https://bibliotekanauki.pl/articles/379771.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
castings defect
simulation codes
cast iron
macromodel
micro model
proces krzepnięcia
wada odlewu
żeliwo
model makro
model mikro
Opis:
The validation of each simulation code used in foundry domain requires individual approach due to its specificity. This validation can by elaborated on the basis of experimental results or in particular cases by comparison the simulation results from different codes. The article concerns the influence of grey cast iron density curve and different forms of solid fraction curve Fs=f(T) on the formation of shrinkage discontinuities. Solid fraction curves applying Newtonian Thermal Analysis (NTA) were estimated. The experimental and numerical simulation tests were performed on the castings, which were made with Derivative Thermal Analysis (DerTA) standard cups. The numerical tests were realized using NovaFlow&Solid (NF&S), ProCast and Vulcan codes. In this work, the coupled influence of both curves on the dynamics of the shrinkage-expansion phenomena and on shrinkage defects prognosis in grey cast iron castings has been revealed. The final evaluation of the simulation systems usefulness should be based on validation experiment, preceded by comparing the simulation results of available systems which are proposed in given technology.
Źródło:
Archives of Foundry Engineering; 2015, 15, 4; 37-44
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Small Wind Turbine Output Model for Spatially Constrained Remote Island Micro-Grids
Autorzy:
Žigman, D.
Meštrović, K.
Tomiša, T.
Powiązania:
https://bibliotekanauki.pl/articles/2172468.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
wind turbine
small wind turbine
decision tree model
artificial neural network model
random forest model
micro-grids
spatially constrained remote Island micro-grids
remote Island micro-grid
Opis:
Modelling operation of the power supply system for remote island communities is essential for its operation, as well as a survival of a modern society settled in challenging conditions. Micro-grid emerges as a proper solution for a sustainable development of a spatially constrained remote island community, while at the same time reflecting the power requirements of similar maritime subjects, such as large vessels and fleets. Here we present research results in predictive modelling the output of a small wind turbine, as a component of a remote island micro-grid. Based on a month-long experimental data and the machine learning-based predictive model development approach, three candidate models of a small wind turbine output were developed, and assessed on their performance based on an independent set of experimental data. The Random Forest Model out performed competitors (Decision Tree Model and Artificial Neural Network Model), emerging as a candidate methodology for the all-year predictive model development, as a later component of the over-all remote island micro-grid model.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2022, 16, 1; 143--146
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining the Key Factors for the Advertisement on Micro Cinema Using Grey Relational Analysis and Dramaturgy Model
Autorzy:
Wu, Jia-Fen
Lee, Tzong-Ru
Jioe, Irsan Prawira Julius
Chien, Chun-Yu
Mendy, Lesse L.
Powiązania:
https://bibliotekanauki.pl/articles/633789.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
micro cinema, micro cinema advertisement, grey relational analysis, dramaturgy model, technology, Mainland China, Taiwanese students
Opis:
Technology advancement has seemingly made the world smaller, especially with the existence of tools such as a cell phone. Along with this development, new method of marketing and promotion has been formed. One of these strategies is the use of micro cinema. After suffiient background study on the factors that seemed to affect the effectiveness of micro cinema, these factors were then used to study the response by Taiwanese students and a working group as well as the working group from Mainland China. Responses obtained from all groups were then analyzed using grey relational analysis (GRA) and then further analyzed using the modifid dramaturgy model by Grove et al. (1992). The result obtained can be used to represent the important factors in micro cinema affecting each group.
Źródło:
International Journal of Synergy and Research; 2018, 7
2083-0025
Pojawia się w:
International Journal of Synergy and Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mass model of microgasturbine single spool turbojet engine
Autorzy:
Czarnecki, M.
Powiązania:
https://bibliotekanauki.pl/articles/247344.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
gas turbine
micro gas turbine
mass model
Schreckling
turbojet
Opis:
Presented paper consists detailed mass model of micro gas turbine single spool turbojet in well-known Scheckling design layout (1R/1A). One of major criteria in aviation is weight that is granted by airworthiness requirements. At present, exempt from certification process are RC airplanes or UAV with total take-off weight less than 22.5 kg. From the 70's mass model was added as a part of aero engines design process. Engine weight affects airplane or UAV weight greatly, because it is a source of variety structure loads. Weight reduction efficiency factor, verifying in terms of design quality a micro gas turbine, and the flying object as a system. Developed computational model allows to estimate weight of the components (gas generator shaft, compressor rotor, compressor diffuser, combustor, turbine nozzle, turbine rotor, jet pipe, casings and housings) and whole engine as well. Model inputs are related to technological axisymmetric dimensions obtained from thermo gas dynamic and construction equations, making it easy to use. Obtained results was presented for several micro gas turbines (mSO1-designed by author, FD3-64, TK-50, JF-50, MW-54, KJ-66, AMT Olympus). Advantage of this model allows to avoid time consuming CAD modelling process at design study level. Presented algorithm can be used also in the design of UAV as well as issues related to the preliminary multidisciplinary design and optimization PMDO cases.
Źródło:
Journal of KONES; 2013, 20, 1; 49-54
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on combustion mode of methanol micro-reciprocating piston internal combustion engine
Autorzy:
Tang, Gang Zhi
Wang, Shuai Bin
Zhang, Li
Shang, Hui Chao
Powiązania:
https://bibliotekanauki.pl/articles/329276.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
micro-energy power systems
combustion diagnosis
combustion model
methanol
silnik spalinowy
diagnostyka spalania
model spalania
metanol
Opis:
Constrained by the micro-space structure, it is proposed to use platinum wire incandescent ignition combustion mode to achieve the operation of internal combustion engine. However, the combustion test of the platinum wire incandescent ignition in miniature piston internal combustion engine shows: the combustion mode of micro-space platinum wire incandescent ignition has a poor combustion characteristic, low heat release rate, long combustion duration, and low combustion pressure. Therefore, a homogenous charge compression ignition mode is proposed to realize the operation of miniature internal combustion engine. However, it is found that the compression combustion cannot be come true in the cold start-up state of the micro engine. And the compression combustion in the first cycle was realized by the way of increasing the temperature of the cylinder block and platinum wire appropriately. The results show that: The maximum heat release rate is obviously improved and the combustion duration shortened by 28.6ºCA, and pmi increased by 76%. So, a novel hybrid combustion mode of in-cylinder compression combustion supported by the platinum wire incandescent ignition is put forward, through the way of adjusting the temperature of platinum wire, and this combustion mode is regarded as the ideal combustion mode of micro reciprocating piston internal combustion engine.
Źródło:
Diagnostyka; 2020, 21, 1; 97-103
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integro-differential form of the first-order dual phase lag heat transfer equation and its numerical solution using the Control Volume Method
Autorzy:
Ciesielski, M.
Mochnacki, B.
Majchrzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/38606551.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
micro-scale heat transfer
dual phase lag model
integro-differential equation
Control Volume Method
Opis:
The start point of the dual phase lag equation (DPLE) formulation is the generalized Fourier law in which two positive constants (the relaxation and thermalization times) appear. This type of equation can be used (among others) to describe the heat conduction processes proceeding in micro-scale. Depending on the number of components in the development of the generalized Fourier law into a power series, one can obtain both the first-order DPLE and the second-order one. In this paper the first-order dual phase lag equation is considered. The primary objective of this research is the transformation of DPLE differential form to the integro-differential one supplemented by the appropriate boundary-initial conditions. The obtained form of the differential equation is much simpler and more convenient at the stage of numerical computations – the numerical algorithm based on the three-time-level scheme reduces to the two-time-level one. To find the numerical solution, the Control Volume Method is used (the heating of thin metal film subjected to a laser beam is considered). The choice of the numerical method was not accidental. The method has a simple physical interpretation ensuring the preservation of the local and global energy balances. To our knowledge, it has not been used so far in this type of tasks. In the final part of the paper the examples of numerical simulations are presented and the conclusions are formulated.
Źródło:
Archives of Mechanics; 2020, 72, 5; 415-444
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of consolidation settlement and creep deformation of artificial island revetment structure in a large-scale marine reclamation land project
Autorzy:
Zhao, J.
Zhou, T.
Wang, G.
Powiązania:
https://bibliotekanauki.pl/articles/258848.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine reclamation land
Soft-Soil-Creep model
consolidation settlement
pore pressure
micro-structure
numerical analysis
Opis:
In order to analyze the influential factors of soft foundation settlement in a marine reclamation land project, the consolidation settlement and pore pressure dissipation of the entire area are numerically simulated using Soft-SoilCreep Model, in which the PLAXIS finite element software for professional geotechnical engineering is applied and empirical data of Japanese Kansai’s airport project are used. Moreover, the figures of settlement and pore pressure results in the different basic period are drawn, and the corresponding analysis conclusions are obtained based on the comparison among the results from the computational parameters of depth. In addition,, the influence rules of various parameters on settlement results is concluded through running the parameter sensitivity analysis in Soft-Soil-Creep Model, and the experience and conclusions can be for reference in the design and con-struction of similar large-scale marine reclamation land project. Also the empirical value method of the creep index has not been applied widely. Further research needs to be done.
Źródło:
Polish Maritime Research; 2015, S 1; 35-42
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of the thermodynamic parameters in failure conditions of the micro-CHP cycle
Autorzy:
Matysko, R.
Mikielewicz, J.
Ihnatowicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/239967.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
micro-CHP system
transient model
failure states
multifuel boiler system
heating system
układ mikro CHP
model przejściowy
stan awaryjny
kocioł
system ogrzewania
Opis:
The paper presents the calculations for the failure conditions of the ORC (organic Rankine cycle) cycle in the electrical power system. It analyses the possible reasons of breakdown, such as the electrical power loss or the automatic safety valve failure. The micro-CHP (combined heat and power) system should have maintenance-free configuration, which means that the user does not have to be acquainted with all the details of the ORC system operation. However, the system should always be equipped with the safety control systems allowing for the immediate turn off of the ORC cycle in case of any failure. In case of emergency, the control system should take over the safety tasks and protect the micro-CHP system from damaging. Although, the control systems are able to respond quickly to the CHP system equipped with the inertial systems, the negative effects of failure are unavoidable and always remain for some time. Moreover, the paper presents the results of calculations determining the inertia for the micro-CHP system of the circulating ORC pump, heat removal pump (cooling condenser) and the heat supply pump in failure conditions.
Źródło:
Archives of Thermodynamics; 2014, 35, 1; 43-59
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the Alternating Direction Implicit Method for numerical solution of the dual phase lag equation
Autorzy:
Ciesielski, M.
Powiązania:
https://bibliotekanauki.pl/articles/281757.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
micro-scale heat transfer
dual phase lag model
control volume method
alternating direction implicit method
numerical simulation
Opis:
The problem discussed in the paper concerns the numerical modeling of thermal processes proceeding in micro-scale described using the Dual Phase Lag Model (DPLM) in which the relaxation and thermalization time appear. The cylindrical domain of a thin metal film subjected to a strong laser pulse beam is considered. The laser action is taken into account by the introduction of an internal heat source in the energy equation. At the stage of numerical modeling, the Control Volume Method is used and adapted to resolve the hyperbolic partial differential equation. In particular, the Alternating Direction Implicit (ADI) method for DPLM is presented and discussed. The examples of computations are also presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 839-852
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suppressing Side-Lobes of Linear Phased Array of Micro-Strip Antennas with Simulation-Based Optimization
Autorzy:
Kozieł, S.
Ogurtsov, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/220985.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear antenna array
micro-strip antenna array
phased antenna array
antenna optimization
antenna array optimization
simulation-based optimization
surrogate model
Opis:
A simulation-based optimization approach to design of phase excitation tapers for linear phased antenna arrays is presented. The design optimization process is accelerated by means of Surrogate-Based Optimization (SBO); it uses a coarse-mesh surrogate of the array element for adjusting the array’s active reflection coefficient responses and a fast surrogate of the antenna array radiation pattern. The primary optimization objective is to minimize side-lobes in the principal plane of the radiation pattern while scanning the main beam. The optimization outcome is a set of element phase excitation tapers versus the scan angle. The design objectives are evaluated at the high fidelity level of description using simulations of the discrete electromagnetic model of the entire array so that the effects of element coupling and other possible interaction within the array structure are accounted for. At the same time, the optimization process is fast due to SBO. Performance and numerical cost of the approach are demonstrated by optimizing a 16-element linear array of microstrip antennas. Experimental verification has been carried out for a manufactured prototype of the optimized array. It demonstrates good agreement between the radiation patterns obtained from simulations and from physical measurements (the latter constructed through superposition of the measured element patterns).
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 193-203
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The problems of hydrodynamic non-isothermal lubrication
Problemy hydrodynamicznego nieizotermicznego smarowania
Autorzy:
Wierzcholski, K.
Powiązania:
https://bibliotekanauki.pl/articles/190086.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
liquid viscosity
changes in thin gap height direction
temperature
adhesion
or phospholipids
analytical model
micro-bearings
joints applications
initial results
lepkość cieczy
zmiany po grubości cienkiej warstwy
temperatura
adhezja
fosfolipidy
model analityczny
mikrołożyska
stawy
wstępne rezultaty
Opis:
The classical hydrodynamic theory of slide bearing lubrication has been constituted on the assumption of constant pressure and viscosity perpendicular to the thin oil layer thickness. These fundamental assumptions are in contradiction to contemporary achievements connected with new devices such as micro-bearing, nano-bearing, magnetic bearings, artificial joints in humanoid robots, micro-motors. Therefore, new methods of measurements and calculations using AFM and a new mathematical computer programs are needed. Energy conservation equations after boundary layer simplifications confirm the fact that temperature gradient variations across the film thickness have the same order of magnitude as the variations in longitudinal or circumferential directions. The fact that temperature gradient variations cross the bearing gap height can be significantly large are evident, despite the temperature differences across the film thickness that are negligibly small. This statement cannot be compliant with the assumption of a constant viscosity value in the gap height direction. It has been proven that hydrodynamic pressure is not constant across the film thickness for non-Newtonian oils with Rivlin Erickson constitutive equations. For pseudo-plastic non-Newtonian oils, the apparent dynamic viscosity significantly decreases with shear rate increases. However, for pseudo-plastic oils, the shear rate increments during the oil flow are strictly connected with the average flow velocity increments. Therefore, the apparent dynamic viscosity depends strongly on the oil velocity gradients. It is evident that flow velocity gradients across the film thickness have intensive variations, particularly in regions where gap height attains the least value. In these places, the dynamic viscosity attains the largest variations in gap height directions. If gap height in micro-bearing is smaller than one micrometre, than the largest oil dynamic viscosity increments caused by the velocity variations across the film thickness are located near the superficial layer of the movable journal surfaces in the case of the hydrodynamic lubrication by rotation, but in the neighbourhood where each of two come near lubricated surfaces during the squeezing. Hence, in these places, dynamic viscosity increases across the film thickness and attains the local maximum values. A gap height smaller than one micrometre has the largest oil dynamic viscosity increments caused by the adhesion force variations across the film thickness located near the motionless sleeve surfaces. In a similar manner, the influences on the viscosity variations caused by the luster points of concentrations of nano particles as oil inhibitors or oil additives smaller than 5 nm occurring in micro-bearing gaps and the cluster concentration regions of collagen fibres occurring in human joint gap are observed. This paper describes and comments on the above-mentioned problem of oil viscosity changes in the gap height direction, and it presents the apparent dynamic viscosity functions for Newtonian and non-Newtonian oils as well indicates the largest viscosity variations in bearing gap height direction and gives examples of initial calculation results.
W niniejszej pracy wykazano, że lepkość dynamiczna nie-newtonowskiego nieizotermicznego czynnika smarującego zmienia się po kierunku wysokości szczeliny łożyskowej oraz że zmiany te mają istotny wpływ na parametry pracy poprzecznego łożyska ślizgowego łącznie z siłami tarcia, współczynnikami tarcia oraz zużyciem materiału. Zmiany lepkości nieizotermicznej nienewtonowskiej cieczy smarującej po grubości warstwy czynnika smarującego uzasadnia się poprzez: · wpływ zmian gradientów temperatury po grubości warstwy smarującej, · wpływ zmian wartości składowych prędkości nienewtonowskiego, nieizotermicznego oleju po kierunku wysokości szczeliny, · wpływ lokalizacji w cieczy smarującej obszarów skupienia (clustering regions) nanometrowych cząsteczek i ich liczebności. Dla wyjaśnienia mechanizmu opisanych wpływów podano komentarze. 1. Zmiany wartości temperatury pomiędzy powierzchnią czopa i panewki są małe i ich wartość osiąga zaledwie od 3 K do 7 K. Dlatego nie mają one wpływu na zmiany lepkości po grubości warstwy, chociaż z równania zachowania energii wynika zmienność wartości temperatury po kierunku wysokości szczeliny łożyska. Jednak zmiany gradientów temperatury po kierunku wysokości szczeliny mogą być znaczące i one wpływają na zmiany lepkości w kierunku wysokości szczeliny. 2. Zmiany wartości składowych prędkości nienewtonowskiego, nieizotermicznego oleju po kierunku wysokości szczeliny są znacząco malejące (rosnące), powodują spadek (wzrost) prędkości deformacji w cieczach nienewtonowskich, a stąd na mocy praw mechaniki cieczy odpowiednio znacząco wzrasta (maleje) lepkość. 3. Obszary skupienia dotyczą: inhibitorów, dodatków polimerowych, zanieczyszczeń solami ołowiu, molekuł magnetycznych o ok. 2–5 nm wielkości cząsteczek w obszarze szczeliny smarnej łożysk mechanicznych oraz chondrocytów, włókien kolagenowych, miceli, liposomów, fosfolipidów o wielkości 5 nm w obszarze cieczy synowialnej wypełniającej szczelinę stawu. Obszary skupienia lokalizują się na ogół w pobliżu współpracujących powierzchni i tam wywołują znaczne wzrosty lepkości pozornej cieczy smarującej. 4. Siły adhezji w szczelinach łożysk o wysokości poniżej mikrometra osiągają największe wartości w pobliżu współpracujących powierzchni, powodując w tych obszarach największe wzrosty lepkości oleju po kierunku wysokości szczeliny.
Źródło:
Tribologia; 2016, 268, 4; 211-223
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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