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Wyświetlanie 1-15 z 304
Tytuł:
Engineering sustainable complex systems
Autorzy:
Ahram, T. Z.
Karwowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/406952.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
systems engineering
sustainability
human factors
human systems integration
complex systems
Opis:
Given the most competitive nature of global business environment, effective engineering innovation is a critical requirement for all levels of system lifecycle development. The society and community expectations have increased beyond environmental short term impacts to global long term sustainability approach. Sustainability and engineering competence skills are extremely important due to a general shortage of engineering talent and the need for mobility of highly trained professionals [1]. Engineering sustainable complex systems is extremely important in view of the general shortage of resources and talents. Engineers implement new technologies and processes to avoid the negative environmental, societal and economic impacts. Systems thinking help engineers and designers address sustainable development issues with a global focus using leadership and excellence. This paper introduces the Systems Engineering (SE) methodology for designing complex and more sustainable business and industrial solutions, with emphasis on engineering excellence and leadership as key drivers for business sustainability. The considerable advancements achieved in complex systems engineering indicate that the adaptation of sustainable SE to business needs can lead to highly sophisticated yet widely useable collaborative applications, which will ensure the sustainability of limited resources such as energy and clean water. The SE design approach proves critical in maintaining skills needed in future capable workforce. Two factors emerged to have the greatest impact on the competitiveness and sustainability of complex systems and these were: improving skills and performance in engineering and design, and adopting SE and human systems integration (HSI) methodology to support sustainability in systems development. Additionally, this paper provides a case study for the application of SE and HSI methodology for engineering sustainable and complex systems.
Źródło:
Management and Production Engineering Review; 2013, 4, 4; 4-14
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of pressure on heat transfer during pool boiling of water-A1[2]0[3] and water-Cu nanofluids on stainless steel smooth tube
Autorzy:
Cieślinski, J.T.
Kaczmarczyk, T.Z.
Powiązania:
https://bibliotekanauki.pl/articles/185613.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanofluid
ciśnienie robocze
pool boiling
operating pressure
Opis:
Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e. water-Al203 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed the test heater. The experiments have been performed to establish the influence of nanofluids concentration on heat transfer characteristics during boiling at different absolute operating pressure values, i.e. 200 kPa, ca. 100 kPa (atmospheric pressure) and 10 kPa. It was established that independent of nanoparticle materials (A1203 and Cu) and their concentration, an increase of operating pressure enhances heat transfer. Generally, independent of operating pressure, sub- and atmospheric pressure, and overpressure, an increase of nanoparticle concentration caused heat transfer augmentation.
Źródło:
Chemical and Process Engineering; 2011, 32, 4; 321-332
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pool boiling of nanofluids on rough and porous coated tubes: experimental and correlation
Autorzy:
Cieśliński, J. T.
Kaczmarczyk, T. Z.
Powiązania:
https://bibliotekanauki.pl/articles/240179.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pool boiling
nanofluids
correlation equation
rough and porous coated tubes
wrzenie w objętości
nanopłyny
równanie korelacyjne
rury z powłoką porowatą
Opis:
The paper deals with pool boiling of water-Al2O3 and water-Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.
Źródło:
Archives of Thermodynamics; 2014, 35, 2; 3-20
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic characteristics of the proton exchange membrane fuel cell module
Autorzy:
Cieśliński, J. T.
Kaczmarczyk, T. Z.
Dawidowicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/240068.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PEM fuel cell
hydrogen
dynamic characteristics
ogniwo paliwowe PEM
wodór
charakterystyka dynamiczna
Opis:
The paper describes a fuel cell based system and its performance. The system is based on two fuel cell units, DC/DC converter, DC/AC inverter, microprocessor control unit, load unit, bottled hydrogen supply system and a set of measurement instruments. In the study presented in the paper a dynamic response of the proton exchange membrane (PEM) fuel cell system to unit step change load as well as to periodical load changing cycles in the form of semi-sinusoidal and trapezoidal signals was investigated. The load was provided with the aid of an in-house-developed electronic load unit, which was fully PC controlled. The apparatus was commissioned by testing the steady-state operation of the module. The obtained efficiency of the fuel cell shows that the test apparatus used in the study provides data in substantial agreement with the manufacturer’s data.
Źródło:
Archives of Thermodynamics; 2018, 39, 4; 125--140
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Damage detection of a T-shaped panel by wave propagation analysis in the plane stress
Wykrywanie uszkodzeń w tarczy typu T z użyciem analizy propagacji fal w płaskim stanie naprężenia
Autorzy:
Rucka, M.
Witkowski, W.
Chróścielewski, J.
Wilde, K.
Powiązania:
https://bibliotekanauki.pl/articles/231134.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wykrywanie uszkodzeń
tarcza stalowa
tarcza typu T
propagacja fal
stan naprężenia płaskiego
damage detection
steel panel
T-shaped panel
wave propagation
spectral element method
Opis:
A computational approach to analysis of wave propagation in plane stress problems is presented. The initial-boundary value problem is spatially approximated by the multi-node C0 displacement-based isoparametric quadrilateral finite elements. To integrate the element matrices the multi-node Gauss-Legendre-Lobatto quadrature rule is employed. The temporal discretization is carried out by the Newmark type algorithm reformulated to accommodate the structure of local element matrices. Numerical simulations are conducted for a T-shaped steel panel for different cases of initial excitation. For diagnostic purposes, the uniformly distributed loads subjected to an edge of the T-joint are found to be the most appropriate for design of ultrasonic devices for monitoring the structural element integrity.
W pracy zaprezentowano podejście obliczeniowe do analizy propagacji fal w płaskim stanie naprężenia. Problem brzegowo-początkowy podlega przestrzennej aproksymacji z użyciem wielowęzłowych, izoparametrycznych, czworobocznych elementów klasy C0. Macierze elementowe są całkowane numerycznie za pomocą kwadratury Gauss-Legendre-Lobatto. Aproksymacje w dziedzinie czasu wykonano za pomocą algorytmu Newmarka. Symulacje numeryczne przeprowadzono dla tarczy w kształcie litery T dla różnych przypadków wzbudzania fali. W pracy wykazano, że dla celów diagnostyki najlepszym rodzajem obciążenia jest obciążenie liniowe równomiernie przyłożone do krawędzi tarczy.
Źródło:
Archives of Civil Engineering; 2012, 58, 1; 3-24
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Application of Acoustic Emission and Artificial Neural Networks in an Analysis of Kinetics in the Phase Transformation of Tool Steel During Austempering
Autorzy:
Łazarska, M.
Woźniak, T. Z.
Ranachowski, Z.
Ranachowski, P.
Trafarski, A.
Powiązania:
https://bibliotekanauki.pl/articles/352705.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carbon steel
austempering
lower bainite
acoustic emission (AE)
neural networks
Opis:
During the course of the study it involved tool steel C105U was used. The steel was austempered at temperatures of 130°C, 160°C and 180°C respectively. Methods of acoustic emission (AE) were used to investigate the resulting effects associated with transformations and a large number of AE events were registered. Neural networks were applied to analyse these phenomena. In the tested signal, three groups of events were identified of: high, medium and low energy. The average spectral characteristics enabled the power of the signal spectrum to be determined. After completing the process, the results were compiled in the form of diagrams of the relationship of the AE incidence frequency as a function of time. Based on the results, it was found that in the austempering of tool steel, in the first stage of transformation midrib morphology is formed. Midrib is a twinned thin plate martensite. In the 2nd stage of transformation, the intensity of the generation of medium energy events indicates the occurrence of bainite initialised by martensite. The obtained graphic of AE characteristics of tool steel austempering allow conclusions to be drawn about the kinetics and the mechanism of this transformation.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 603-609
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Application of Neural Networks for Studying Phase Transformation by the Method of Acoustic Emission in Bearing Steel
Zastosowanie sieci neuronowych do badania przemian fazowych w stali łożyskowej metodą emisji akustycznej
Autorzy:
Woźniak, T. Z.
Ranachowski, Z.
Ranachowski, P.
Ozgowicz, W.
Trafarski, A.
Powiązania:
https://bibliotekanauki.pl/articles/354378.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bearing steel
austempering
lower bainite
acoustic emission
neural networks
łożyska stalowe
hartowanie
bainit dolny
emisja akustyczna
sieci neuronowe
Opis:
The research was carried out on steel 100CrMnSi6-4 under isothermal austempering resulting in forming the duplex structure: martensitic and bainitic. The kinetics of transformation was controlled by the acoustic emission method. Complex phase transformations caused by segregation and carbide banding occur at the low-temperature heat treatment of bearing steel. At the temperature close to Ms, a certain temperature range occurs where an effect of the first product of prior athermal martensite on the bainitic transformation can be observed. In the registered signal about 15 million various events were registered. There were considered three types of acoustic emission events (of high, medium and low energy), with relatively wide sections and with different spectral characteristics. It was found that the method of acoustic emission complemented by the application of neural networks is a sensitive tool to identify the kinetics of bainitic transformation and to show the interaction between martensitic and bainitic transformations.
Badania realizowano na stali 100CrMnSi6-4 poddanej hartowaniu izotermicznemu, prowadzacemu do utworzenia struktury duplex: martenzytyczno-bainitycznej. Kinetykę przemian kontrolowano metodą emisji akustycznej. Przy niskotemperaturowej obróbce cieplnej stali łożyskowej występują złożone przemiany fazowe spowodowane segregacją i pasmowością węglików. W temperaturze zbliżonej do Ms, występuje pewien zakres temperatury, gdzie zaznacza się oddziaływanie wcześniejszego produktu przemiany martenzytycznej na przemianę bainityczną. W zarejestrowanym sygnale zarejestrowano około 15 milionów różnych zdarzeń. Uwzgledniono trzy rodzaje zdarzeń emisji akustycznej (o wysokiej, średniej i niskiej energii) o względnie szerokich przedziałach, o różnej charakterystyce widmowej. Stwierdzono, że metoda emisji akustycznej uzupełniona o zastosowanie sieci neuronowych jest czułym narzędziem do identyfikacji kinetyki przemiany bainitycznej oraz oddziaływania przemiany martenzytycznej na przemianę bainityczną.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 4; 1705-1712
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 304

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