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Wyświetlanie 31-45 z 73
Tytuł:
Combustability of building products versus fire safety
Autorzy:
Fangrat, J.
Powiązania:
https://bibliotekanauki.pl/articles/200506.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
building performance
buildings fire safety
building products
fire properties
Euroclass
wydajność budowy
bezpieczeństwo pożarowe
wyroby budowlane
Euroklasa
Opis:
The combustion process is described and analysed based on the experimental results in the context of building fire safety. Data are obtained by means of five standard methods: ISO 5657 ignitability test, ISO 5657 cone calorimeter, ISO 9705 room corner test, EN ISO 1716 small calorimeter, and EN ISO 1182 small furnace. Various categories of building products were tested: cellulose based products (particle boards, plywoods), solid wood, floor coverings, concrete, ceramics, insulations (thermal and/or acoustic), boards (wall/ceiling), mortars, adhesives, and thin coatings. The studied products exhibited very different fire properties from non-combustible to easily combustible. In order to more effectively differentiate non-combustibles and combustibles within building products, the modified heat of combustion was calculated using all test results according to EN ISO 1716 and EN ISO 1182. The revision of criteria for Euro class A1 and A2 is proposed to obtain more realistic reaction-to-fire evaluation. In conclusion, it is advised to use single limit for heat of combustion for A1 and A2 Euro class. The proposed approach for modified heat of combustion is a convenient tool for the fast and cost-effective initial test method for non-combustibility evaluation and seems to be the proper method for distinguishing between non-combustibles and combustibles within building products. It is a better reflection of the real physical process of combustion than the current one. The third A1 criterion is questionable, regarding time to auto-ignition in EN ISO 1182 cylindrical furnace. The measurement for gross heat of combustion by EN ISO 1716 method is proposed for all Euro classes of building products with different limit values.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 4; 709-717
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving Efficiency of CCS Numerical Simulations Through Use of Parallel Processing
Poprawa wydajności obliczeń numerycznych symulacji COS poprzez wykorzystanie przetwarzania równoległego
Autorzy:
Konopka, K.
Miłkowska-Piszczek, K.
Trębacz, L.
Falkus, J.
Powiązania:
https://bibliotekanauki.pl/articles/356050.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous casting of steel
efficiency of numerical calculations
numerical modelling
ProCAST
ciągłe odlewanie stali
wydajność obliczeń numerycznych
modelowanie numeryczne
Opis:
The study presents the findings of research concerning the possibilities for application of parallel processing in order to reduce the computing time of numerical simulations of the steel continuous casting process. The computing efficiency for a CCS model covering the mould and a strand fragment was analysed. The calculations were performed with the ProCAST software package using the finite element method. Two computing environments were used: the PL-Grid infrastructure and cloud computing platform.
W pracy przedstawiono wyniki badań dotyczących możliwości zastosowania przetwarzania równoległego w celu skrócenia czasu trwania obliczeń numerycznych symulacji procesu ciągłego odlewania stali. Przeanalizowano wydajność obliczeń dla modelu COS obejmującego krystalizator i fragment pasma. Obliczenia przeprowadzono przy pomocy pakietu oprogramowania ProCAST w oparciu o metodę elementów skończonych. Wykorzystano dwa środowiska obliczeniowe: infrastrukturę PL-Grid i chmurę obliczeniową.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 1; 235-238
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the conditions for the exhaustion of the stability margin in the rail track of freight cars with three-piece bogies
Autorzy:
Domin, Yurii V.
Domin, Rostysla Yu.
Cherniak, Ganna Yu.
Nozhenko, Volodymyr S.
Powiązania:
https://bibliotekanauki.pl/articles/1833607.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
freight cars
derailment
traffic safety
dynamic performance
computer simulation
wagony towarowe
wykolejenie
bezpieczeństwo na drodze
wydajność dynamiczna
symulacja komputerowa
Opis:
The research on improvement of methodical approaches to definition of the probable reasons of infringement of conditions of stability of freight cars from derailment is carried out. Using a basic computer model of the dynamics of a freight car, the influence of the characteristics of the technical condition of their running gear and track on the indicators of empty cars stability from derailment was studied through the computational experiment. The article presents the main statements of the research methodology, which provides the analysis of probable causes of derailment of freight cars by conducting a series of numerical experiments with logging the progress of calculations and saving the results. Factor analysis was used to interpret the calculated data with an assessment of each of the factors influence or their combination on the probability of derailment. The developed procedure of the simulation experiment provides a step-by-step study of the freight cars derailment conditions, including factors structuring and ranking, development of experimental plan, calculating coefficients of wheel pairs resistance to derailment from rails, provided that the wheel flange rolls onto the rail head, and determining the degree of influence of relevant factors on the dynamic stability of cars from derailment. A comparative analysis of the stability of cars in rail tracks was performed using the introduced concept of the combined coefficient of stability of wheel pairs against derailment. Determining the probable causes of car derailment is based on scanning the parameter field. The results of the parametric study revealed the degree of influence on the freight cars stability of running gear technical condition characteristics. In particular, it is determined that the most dangerous in terms of stability loss of empty cars in the track is the exceeding of the wedges of the vibration dampers.
Źródło:
Archives of Transport; 2021, 57, 1; 119-129
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of new chemical test reactions to study mass transfer from shrinking droplets and micromixing in the rotor-stator mixer
Autorzy:
Bałdyga, J.
Kotowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/184911.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
efficiency of mixing
mass transfer
micromixing
rotor-stator mixer
test reaction
wydajność mieszania
transfer masy
mikromieszanie
reakcja testowa
Opis:
A pair of fast competitive reactions, neutralization and 2,2-dimetoxypropane (DMP) hydrolysis, has been applied do study mass transfer and micromixing in a T 50 Ultra-Turrax® - IKA rotor-stator device. In experiments the dispersed organic phase containing p-Toluenesulfonic acid (pTsOH) dissolved in diisopropyl ether, whereas the continuous phase was represented by the aqueous solution of sodium hydroxide, 2,2-dimetoxypropane (DMP) and ethanol. During mixing a fast mass transfer of a solute (pTsOH) from organic phase droplets, which were shrinking due to fast dissolution of the organic solvent, was followed by micromixing and chemical reactions in the continuous phase. Measured hydrolysis yields were applied to express effects of mixing on the course of chemical reactions. Modeling was based on application of models describing drop breakup, mass transfer in the liquid-liquid system and micromixing. Combined effects of mass transfer and drop breakage on drop population were expressed using the population balance equations. The model has been used to interpret experimental results, in particular to identify the efficiency of mixing.
Źródło:
Chemical and Process Engineering; 2017, 38, 3; 477-489
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance comparison of different aerodynamic shapes for autonomous underwater vehicles
Autorzy:
Khalin, Anatoliy
Kizilova, Nataliya
Powiązania:
https://bibliotekanauki.pl/articles/139785.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autonomous underwater vehicle
aerodynamic performance
lifting force
CFD modeling
autonomiczny pojazd podwodny
wydajność aerodynamiczna
siła podnoszenia
modelowanie CFD
Opis:
A brief review of the existing autonomous underwater vehicles, their types, design, movement abilities and missions is presented. It is shown, the shape optimization design and enhancement of their efficiency is the main problem for further development of multipurpose glider technologies. A comparative study of aerodynamic performance of three different shape designs (the airfoil NACA0022 based (I), flattened ellipsoidal (II) and cigar-type (III) bodies of the same volumes) has been carried out. Geometrical modelling, meshing and computational fluid dynamics (CFD) simulations have been carried out with AnSys15.0. The pathlines and wall shear stress distributions have been computed to understand the advantages and disadvantages of each shape. The lift and drag coefficients, aerodynamic quality, power index and pitching moment have been computed. The higher efficiency of the shape I/shape II at higher/lower angles of attack (greater than 20o and less than 20o) has been found. The shape III develops high speeds at the same angles of attack and has higher manoeuvrability at relatively low aerodynamic quality. The comparative analysis of the flow capabilities of studied autonomous undersea vehicles proposes some design improvement for increasing their energy efficiency and flow stability.
Źródło:
Archive of Mechanical Engineering; 2019, LXVI, 2; 171-189
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary evaluation of seismic performance of engineering structures with perform 3D
Autorzy:
Li, Dongmei
Powiązania:
https://bibliotekanauki.pl/articles/230293.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PERFORM 3D
analiza elasto-plastyczna
wydajność sejsmiczna
kąt przemieszczenia
kondygnacja
elastoplastic analysis
seismic performance
storey
displacement angle
Opis:
This study analyzed the role of PERFORM 3D in the preliminary evaluation of seismic performance of engineering structures. Firstly, PERFORM 3D was briefly introduced, and its material constitutive model and basic model were analyzed. Then, taking a high-rise building project in Yulin, Shaanxi, China, as an example, PERFORM 3D was used to evaluate its seismic performance. After establishing the engineering model, five seismic waves were selected for simulation. The results showed that the maximum values of X-axis inter-story displacement angle and Y-axis displacement angle were 1/500 and 1/360 respectively, which were far less than the standard limit; the overall energy dissipation was good, the damping was small, the overall deformation was good, and the seismic performance was also good. In conclusion, PERFORM 3D has a good performance in the preliminary evaluation of seismic performance of engineering, and it is worth further promotion and application.
Źródło:
Archives of Civil Engineering; 2019, 65, 4; 189-201
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of labour efficiency supported by the ensembles of neural networks on the example of steel reinforcement works
Analiza wydjaności pracy wspomagana zespołem sieci neuronowych na przykładzie robót zbrojarskich
Autorzy:
Juszczyk, Michał
Powiązania:
https://bibliotekanauki.pl/articles/230439.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wydajność pracy
sieć neuronowa
prognoza
roboty zbrojarskie
zbrojenie stalowe
labour efficiency
neural network
prediction
reinforcement works
steel reinforcement
Opis:
This study presents an artificial intelligence technique based on ensemble of artificial neural networks for the purposes of analysis and prediction of labour productivity. The study focuses on the development of model that combines several artificial neural networks on the basis of real-life data collected on a construction site for steel reinforcement works. The data includes conditions, characteristics, features of steel reinforcement works and related efficiencies of workers assigned to particular tasks recorded on site. The proposed ensemble based model combines five supervised learning models - five different multilayer perceptron networks, which contribution in the prediction is weighted due to the application of generalised averaging approach. Testing results show that the proposed ensemble based model achieves the satisfactory evaluation criteria for coefficient of correlation (0.989), root-mean-squared error (2.548), mean absolute percentage error (4.65%) and maximum absolute percentage error (8.98%).
Wydajność pracy ma kluczowy wpływ na czas realizacji i koszty przedsięwzięć budowlanych. W publikacji przedstawiono wyniki prac badawczych nad wykorzystaniem zespołów sztucznych sieci neuronowych w analizie i predykcji wydajności pracy na przykładzie robot zbrojarskich. Analiza została przeprowadzona w oparciu dane zbierane przez wykonawcę w trakcie realizacji robót. Celem pracy badawczej była ocena przydatności danych zebranych przez wykonawcę robot oraz proponowanego narzędzia matematycznego do analizy i predykcji wydajności pracy.
Źródło:
Archives of Civil Engineering; 2020, 66, 1; 97-111
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pre-stress losses in FRP pre-stressed reinforced concrete – subject overview
Autorzy:
Przygocka, M.
Kotynia, R.
Powiązania:
https://bibliotekanauki.pl/articles/231356.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FRP
wydajność długoterminowa
napięcie wstępne
strata sprężania
relaksacja
reologia
long-term performance
pre-tensioning
prestress loss
relaxation
rheology
Opis:
This paper discuss the issue of pre-stress losses which occur in the FRP prestressed concrete structures. The prestress losses consist of immediate losses just after pre-tensioning of the FRP composite and time-dependent losses. Prestress losses are affected by different factors as strength properties of used materials, ambient temperature, humidity, UV radiation, bond between the FRP material and RC specimen, type of anchorage and creep of prestressing system. Two types of tests can be found in the available literature: material samples subjected to sustained uniaxial tension which verify the relaxation of FRP tendons (Wang et al., Sasaki and Nishizaki, Shi et al and Oskouei and Taleie) and flexural tests of RC beams strengthened with pre-tensioned FRPs (Wang et al.). Authors considered different types of composites: carbon (Wang et al, Sasaki and Nishizaki, Oskouei and Taleie), aramid (Sasaki and Nishizaki, Oskouei and Taleie), glass (Sasaki and Nishizaki), vinyl (Sasaki and Nishizaki) and basalt (Shi et al.).
Źródło:
Archives of Civil Engineering; 2018, 64, 4/II; 257-268
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient learning variable impedance control for industrial robots
Autorzy:
Li, C.
Zhang, Z.
Xia, G.
Xie, X.
Zhu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/200716.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
variable impedance control
reinforcement learning
efficient
Gaussian process
industrial robots
impedancja
poprawa efektywności
wydajność
model Gaussa
roboty przemysłowe
Opis:
Compared with the robots, humans can learn to perform various contact tasks in unstructured environments by modulating arm impedance characteristics. In this article, we consider endowing this compliant ability to the industrial robots to effectively learn to perform repetitive force-sensitive tasks. Current learning impedance control methods usually suffer from inefficiency. This paper establishes an efficient variable impedance control method. To improve the learning efficiency, we employ the probabilistic Gaussian process model as the transition dynamics of the system for internal simulation, permitting long-term inference and planning in a Bayesian manner. Then, the optimal impedance regulation strategy is searched using a model-based reinforcement learning algorithm. The effectiveness and efficiency of the proposed method are verified through force control tasks using a 6-DoFs Reinovo industrial manipulator.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 201-212
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities of increasing production efficiency by implementing elements of augmented reality
Autorzy:
Trojanowska, Justyna
Kaščak, Jakub
Husár, Jozef
Knapčíková, Lucia
Powiązania:
https://bibliotekanauki.pl/articles/2173703.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
production efficiency
production equipment
augmented reality
Industry 4.0
maintenance
wydajność produkcji
sprzęt produkcyjny
rozszerzona rzeczywistość
Przemysł 4.0
utrzymanie
Opis:
The publication reflects the current situation concerning the possibilities of using augmented reality (AR) technology in the field of production technologies with the main intention of creating a tool to increase production efficiency. It is a set of individual steps that respond in a targeted manner to the possible need for assisted service intervention on a specific device. The publication chronologically describes the procedure required for the preparation and processing of a CAD model. For this preparatory process, the PTC software package is used which meets the requirements for each of the individual operations. The first step is the routine preparation of CAD models and assemblies. These are prepared based on real models located on the device, and their shape and dimensions correlate with the dimensions of the model on the device. The second phase is the creation and timing of the disassembly sequence. This will provide the model with complete vector data, which is then paired with the CAD models in AR. This phase is one of the most important. It determines the location of the model concerning its relative position on the device, provides information on the relocation of parts of the model after the sequence is started, and essentially serves as a template for the interactive part of the sequence. The last two phases are used to connect CAD models with vector data, determine their position for the position mark, and prepare the user interface displayed on the output device. The result of this procedure is a functional disassembly sequence, used for assisted service intervention of a worker in the spindle drive of the Emco Mill 55 device.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 6; art. no. e143831
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Operational problems of 2+1 bypass road sections
Autorzy:
Tracz, M.
Kieć, M.
Powiązania:
https://bibliotekanauki.pl/articles/223969.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bypass
lane road
speed
overtaking
traffic performance
operating
travel speed
obwodnica
pas drogowy
prędkość jazdy
wyprzedzanie
wydajność ruchu
bezpieczeństwo
Opis:
The paper presents several problems of designing trunk-road bypasses of towns, which can be very helpful in improving their traffic performance. Such roads perform supplementary functions to the operation of network of motorways and express-roads constructed in Poland over the last decade. These problems include: selection of the cross section, selection and design of intersections and interchanges on bypasses, safety and traffic operation problems. The authors highlight the advantages of bypasses and point out some errors, which can be seen in the operation stage, basing on research and observation of 8 bypasses. In the paper traffic operation and road safety analyses for Zyrardow bypass are presented. The final part of the paper gives conclusions and recommendations for 2+1 bypass use and design.
Źródło:
Archives of Transport; 2016, 38, 2; 79-89
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of various mining equipment used for roadway development in coal mines
Ocena efektywności specjalistycznego sprzętu górniczego używanego do drążenia chodników w kopalniach węgla
Autorzy:
Su, Okan
Powiązania:
https://bibliotekanauki.pl/articles/219303.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wydajność produkcji
tempo penetracji skał
prace strzałowe
wyrobiska skalne
drążenie tuneli
production rate
penetration rate
blasthole drilling
mine roadway
rock excavation
Opis:
This study attempts to evaluate the field performance of various mining equipment used at the development galleries of coal mines. These are hand-held and jumbo rock drills, and a road header used in mechanical excavation. For this purpose, the penetration rates of rock drills were monitored and measured in the field. The physical, mechanical, and drillability properties were determined through the collected samples in order to understand the complex interactions between the rock and bit/pick. The abrasive mineral content was also analyzed with XRD analysis to examine the wear on the cutting/drilling tools. Besides, the specific energy of the equipment was calculated relying on the operational parameters. A comparison of the monthly advance and production rates of the drilling rigs and roadheader was made. The relations among operating power, specific energy, and design of buttons/picks were investigated. It has been found that the average advance and production rates of the mining equipment are consistent with the penetration rate. The results verified that the roadheader used in mechanical excavation and the jumbo drill used in drilling and blasting technique are the machines maximizing the advance and production rates.
W artykule podjęto próbę oceny efektywności pracy sprzętu górniczego rozmaitego typu, wykorzystanego do drążeniach chodników w kopalniach węgla, np. wszelkiego rodzaju urządzeń wiertniczych od wiertarek ręcznych po wozy wiertnicze oraz urządzenia do drążenia tuneli i wyrobisk. W tym celu monitorowano i mierzono skuteczność i tempo penetracji skał przy użyciu urządzeń ręcznych oraz wozów wiertniczych w warunkach terenowych. Własności fizyczne, mechaniczne oraz urabialność skał określano na podstawie badania zebranych próbek, co umożliwia pełniejsze zrozumienie złożonych oddziaływań pomiędzy skałą a wiertłem/ końcówką. Zawartość substancji ściernych określono w oparciu o metodę analizy rentgenowskiej dyfrakcyjnej (XRD) i na tej podstawie określano zużycie narzędzi wiertniczych i urabiających. Poziom energii rozporządzalnej obliczono w oparciu o parametry eksploatacyjne sprzętu. Porównano miesięczne wyniki postępu i wydajności pracy poszczególnych urządzeń wiertniczych i urządzenia do drążenia tuneli. Zbadano zależności pomiędzy wydajnością roboczą i energią rozporządzalną a konstrukcją końcówek odpowiednich narzędzi. Stwierdzono że średni postęp i średnia wydajność robocza urządzeń idą w parze z tempem wnikania (penetracji skał). Uzyskane wyniki potwierdziły, że maksymalny postęp pracy i wydajność produkcji osiągnąć można dzięki zastosowaniu urządzenia do drążenia tuneli wykorzystywanego do drążenia wyrobisk, wozów wiertniczych do prac otworowych oraz technik strzałowych.
Źródło:
Archives of Mining Sciences; 2019, 64, 4; 797-812
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of CFD simulations of the flow pattern in an agitated system with a pitched blade worn turbine
Autorzy:
Skocilas, J.
Fort, I.
Jirout, T.
Powiązania:
https://bibliotekanauki.pl/articles/185244.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pitched blade impeller
erosion wear
ensemble-average mean velocity
impeller
pumping capacity
CFD simulation
prędkość uśredniona
wirnik
wydajność pompy
symulacji CFD
Opis:
This paper presents a numerical analysis of an agitated fully baffled cylindrical vessel with a down pumping four blade worn or unworn pitched blade impeller (= 45[degrees] and 30[degrees]) under a turbulent flow regime. CFD simulations predict the pumping capacity of the system equipped by worn and unworn pitched blade impeller. Experimental data were taken from the authors’ previous work and compared with results of numerical computations. A good agreement with experimental data was obtained. The ensemble-average mean velocity field with worn and unworn impellers was computed. It follows from the simulation results that the wear rate of the impeller blade has a significantly negative effect on the velocity distribution in an agitated liquid. The greater the destruction of the worn blade, the higher is the deformation of the velocity field around the rotating impeller, with a simultaneous decrease in impeller pumping capacity.
Źródło:
Chemical and Process Engineering; 2013, 34, 1; 39-49
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying OpenMP thread mapping for parallel linear algebra kernels on multicore system
Autorzy:
Bylina, B.
Bylina, J.
Powiązania:
https://bibliotekanauki.pl/articles/200778.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
computation performance
OpenMP standard
nonnegative matrix factorization
thread mapping
energy consumption
wydajność obliczeniowa
Standard OpenMP
nieujemna faktoryzacja macierzy
mapowanie
zużycie energii
Opis:
Thread mapping is one of the techniques which allow for efficient exploiting of the potential of modern multicore architectures. The aim of this paper is to study the impact of thread mapping on the computing performance, the scalability, and the energy consumption for parallel dense linear algebra kernels on hierarchical shared memory multicore systems. We consider the basic application, namely a matrix-matrix product (GEMM), and two parallel matrix decompositions (LU and WZ). Both factorizations exploit parallel BLAS (basic linear algebra subprograms) operations, among others GEMM. We compare differences between various thread mapping strategies for these applications. Our results show that the choice of thread mapping has the measurable impact on the performance, the scalability, and energy consumption of the GEMM and two matrix factorizations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 6; 981-990
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steady-state and transient heat transfer through fins of complex geometry
Autorzy:
Taler, D.
Taler, J.
Powiązania:
https://bibliotekanauki.pl/articles/240664.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fin of complex geometry
fin efficiency
finite volume method
finite element method
geometria złożona
wydajność
metoda objętości skończonych
metoda elementów skończonych
Opis:
Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.
Źródło:
Archives of Thermodynamics; 2014, 35, 2; 117-133
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 31-45 z 73

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