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Wyświetlanie 1-14 z 14
Tytuł:
Competitive Nucleation in Grey Cast Irons
Autorzy:
Arab, N.
Powiązania:
https://bibliotekanauki.pl/articles/382159.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast iron
competitive nucleation
undercooling
cooling curve
grain refining
żeliwo
nukleacja
przechłodzenie
krzywa krzepnięcia
rozdrabnianie ziarna
Opis:
Cast irons are good examples of materials which are more sensitive to chemical composition and production conditions. In this research to improve casting quality, solidification and nucleation process in grey cast iron was investigate. In particular, attempts have been made to rationalize variation in eutectic cells with nucleation sites and eutectic solidification undercooling. Four castings with different diameter and similar chemical composition and pouring temperature and different inoculant percentage was casted. The cooling curve and maximum and minimum undercooling for each castings was measured. Also optical metallography and image analyzer has been used to determine the average eutectic cells diameter, and linear and surface densities, and volume density was calculated. The results of this research show a competitive behavior between nucleation sites and eutectic undercooling. Higher nucleation sites and higher eutectic undercooling cause higher eutectic cell density. But increasing nucleation sites by introducing inoculants to molten metal, is accompanied with reduction in eutectic undercooling. It means that inoculation and undercooling have opposite effect on each other. So, to achieve maximum cell density, it is necessary to create an optimization between these parameters.
Źródło:
Archives of Foundry Engineering; 2017, 17, 4; 185-189
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Elaboration Conditions on the Structural, Morphological and Luminescence Properties of ZnO Nanopowders
Autorzy:
Arab, L.
Guergouri, K.
Powiązania:
https://bibliotekanauki.pl/articles/1401219.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
81.07.Wx
81.20.Fw
07.57.Ty
78.55.Qr
68.37.Hk
Opis:
Pure ZnO nanopowders were synthesized by the sol-gel method, which has several advantages, among which we include, achieving low temperature deposition and synthesis of new hybrid organo-mineral materials. The effect of the elaboration conditions (the elaboration concentrations ratio of precursors $(C_{Z}//C_{A})$, the gelling temperature $(T_g)$ and the gelling time $(t_g)$) on the structural, morphological and luminescence properties of ZnO nanopowders has been investigated. The chemical composition of the powders, determined by FTIR spectroscopy, indicate the exclusive presence of Zn-O bonds, as it is shown by the XRD spectra. The XRD results indicate also that the synthesized ZnO powder is a solid solution, crystallizing in pure würtzite structure with a minimum grain size of about 23 nm for the powders prepared using: $C_{Z}//C_{A}$=0.06%, $T_g$=130°C and $T_g$=4 h. The morphological aspect, given by the SEM images, revealed that the powders are made of sheets, consisting of small particles agglomerated together. The photoluminescence study of the ZnO powders shows spectra with luminescence peaks from green to ultraviolet light, the more intensive emission is connected to the peaks of the blue luminescence.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 940-942
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Humour and belonging: a thematic review
Autorzy:
Arab, Reza
Milner Davis, Jessica
Powiązania:
https://bibliotekanauki.pl/articles/2098506.pdf
Data publikacji:
2022-08-11
Wydawca:
Krakowskie Towarzystwo TERTIUM
Tematy:
humour
laughter
belonging
inclusion
exclusion
Opis:
Serving as introduction to this Special Issue, this article presents a thematic review of topics involved in studies on humour and belonging. It briefly elaborates on the intricacies of concepts such as humour, sense of humour and belonging and their relationships. It then provides a selective review of some major relevant studies. Finally, the themes and contents of the Special Issue are introduced.
Źródło:
The European Journal of Humour Research; 2022, 10, 2; 1-13
2307-700X
Pojawia się w:
The European Journal of Humour Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Globotriaosyl ceramide (Gb_3) expression in human tumour cells: Intracellular trafficking defines a new retrograde transport pathway from the cell surface to the nucleus, which correlates with sensitivity to verotoxin
Autorzy:
Lingwood, Clifford
Khine, Aye
Arab, Sara
Powiązania:
https://bibliotekanauki.pl/articles/1044809.pdf
Data publikacji:
1998
Wydawca:
Polskie Towarzystwo Biochemiczne
Źródło:
Acta Biochimica Polonica; 1998, 45, 2; 351-359
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Taguchi Method for Investigating the Mechanical Properties of a Microalloyed Steel
Zastosowanie metody Taguchi do badania właściwości mechanicznych stali niskostopowych
Autorzy:
Ayaz, M.
Arab, N. B.
Khaki, D. M.
Powiązania:
https://bibliotekanauki.pl/articles/353590.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Taguchi method
strain hardening exponent
yield strength
microalloyed steel
hot rolling
metoda Taguchi
wykładnik utwardzenia
granica plastyczności
stal niskostopowa
walcowanie na gorąco
Opis:
In the present investigation, the effects of processing parameters, such as roughing, finishing and coiling temperatures, on the strain hardening exponent and yield strength of a Nb-microalloyed steel has been studied by Taguchi method. In order to achieve maximum n-value and yield strength, tests were done in a laboratorial pilot considering a L16 orthogonal array of Taguchi method under following condition: roughing temperature of 1000, 1050, 1100, 1150°C, finishing temperature of 800, 850, 900, 950°C, coiling temperature of 550, 600, 650, 700°C. Then, analysis of variance and signal to noise ratios are performed on the measured data. The results indicated that the finishing and coiling temperatures were the major factor affecting the mechanical properties. The confirmation tests at optimal conditions approve the effectiveness of this robust design methodology in investigating the hot rolling process of the microalloyed steels.
W niniejszej pracy, metodą Taguchi badano wpływ parametrów obróbki takich jak temperatura obróbki zgrubnej, wykańczającej i zwijania na wykładnik utwardzenia i granicę plastyczności stali niskostopowej. W celu uzyskania maksymalnej wartości wykładnika n i granicy plastyczności, badania przeprowadzono w skali laboratoryjnego pilota uwzględniając ortogonalną macierz L16 metody Taguchi pod następującymi warunkami: temperatura obróbki zgrubnej: 1000, 1050, 1100, 1150° C, temperatura obróbki wykańczającej: 800, 850, 900, 950° C, temperatura zwijania: 550, 600, 650, 700° C. Następnie dokonano analizy wariancji stosunku sygnału do szumu na zmierzonych danych. Wyniki wskazują, że temperatury obróbki wykończeniowej i zwijania były głównym czynnikiem wpływającym na własności mechaniczne. Testy przeprowadzone w optymalnych warunkach potwierdziły skuteczności zaprojektowanej metodologii w badaniach procesu walcowania na gorąco stali niskostopowych.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 3; 853-858
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shear strength of compacted Chlef sand: effect of water content, fines content and others parameters
Autorzy:
Bouri, Djamel
Krim, Abdallah
Brahim, Abdelkader
Arab, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/178905.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fines content
water content
direct shear test
friction angle
cohesion
Opis:
This paper presents a laboratory study of the combined effect of the water content and fines content on the mechanical behaviour of Chlef sand in a medium dense state (RD = 65%) and dense state (RD = 80%). Several mechanical parameters were evaluated such as shear strength, cohesion and friction angle at different water content w = 0, 1, 2 and 3% and different fines content Fc = 0, 10, 20, 30 and 40%. The test results showed that the shear strength of Chlef sand decrease with the increase fines content Fc = 0 to 40%, our tests result also showed that the water content has a significant influence on the shear strength which decreases with the increase in the water content w = 0 to 3%. The fines content and the water content have a significant influence on the mechanical parameters c and ɸ. Cohesion increases with the percentage of fines and decreases with the increase of the water content while the friction angle decreases with the increase the fines content and the water content.
Źródło:
Studia Geotechnica et Mechanica; 2020, 42, 1; 18-35
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shear Strength Enhancement of Cemented Reinforced Sand: Role of Cement Content on the Macro-Mechanical Behavior
Autorzy:
Boutouba, Kheira
Benessalah, Ismail
Arab, Ahmed
Henni, Ahmed Djafar
Powiązania:
https://bibliotekanauki.pl/articles/178198.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cemented reinforced sand
direct shear test
water content
curing time
dilatant character
Opis:
Sands reinforced by hydraulic binders (cement) have constituted in recent decades a major asset for the expansion of several areas of engineering. The mechanical behavior of sand-cement mixtures has undergone some controversies studied on the Chlef sand. In this paper, we present an experimental study to investigate the mechanical behavior of a sandy soil reinforced by a hydraulic binder (cement), using the direct shear apparatus emphasizing on the shear strength characteristics and the vertical deformation variation of cemented reinforced sand. The parameters used in this study are mainly: relative density (Dr = 80%), normal stress (σn = 100, 200, 400 kPa), water content (3, 7 and 10%), cement content (2.5, 5, 7.5 and 10 %) and cure time (7, 14 and 28 days). The experimental results show that the mechanical characteristics in terms of internal cohesion (C) and internal frication angle (φ) give a better mechanical performance with the binder inclusion, and the cure conditions play an effective role on the improvement of the shear strength. This result also showed that 10% of the cement content gave us a maximum value of shear strength and an optimal influence on the mechanical characteristics. The addition of cement not only improves the shear strength of soil, but also provides diversity in the resistance against the deformations imposed load, which can be established by a dilatant character.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 4; 200-211
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Psychoacoustic Annoyance on EEG Signals of Tractor Drivers
Autorzy:
Lashgari, Majid
Arab, Mohammad Reza
Nadjafi, Mohsen
Rafiee, Mojtaba
Powiązania:
https://bibliotekanauki.pl/articles/31339953.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
EEG
Higuchi
fractal
tractor
sound.
Opis:
The purpose of this study was to evaluate the psychoacoustic annoyance (PA) that the tractor drivers are exposed to, and investigate its effects on their brain signals during their work activities. To this aim, the sound of a garden tractor was recorded. Each driver’s electroencephalogram (EEG) was then recorded at five different engine speeds. The Higuchi method was used to calculate the fractal dimension of the brain signals. To evaluate the amount of acoustic annoyance that the tractor drivers were exposed to, a psychoacoustic annoyance (PA) model was used. The results showed that as the engine speed increased, the values of PA increased as well. The results also indicated that an increase in the Higuchi’s fractal dimension (HFD) of alpha and beta bands was due to the increase of the engine speed. The regression results also revealed that there was a high correlation between the HFD of fast wave activities and PA, in that, the coefficients of determination were 0.92 and 0.91 for alpha and beta bands, respectively. Hence, a good correlation between the EEG signals and PA can be used to develop a mathematical model which quantifies the human brain response to the external stimuli.
Źródło:
Archives of Acoustics; 2022, 47, 4; 469-477
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Economical reactive powder concrete cast using available materials in North Sinai, Egypt
Autorzy:
Meleka, N. N.
Bashandy, A. A.
Arab, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/231066.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
proszek reaktywny
beton
właściwości mechaniczne
zawartość
cement
pył krzemionkowy
włókno stalowe
reactive powder
concrete
mechanical properties
silica fume
steel fiber
Opis:
In this research reactive powder concrete (RPC) was prepared using sand from North Sinai. The mechanical properties of locally cast RPC were investigated and evaluated by studying the effects of using different cement and silica fume contents and new steel fibers’ aspect ratios as reinforcement for RPC. Specimens’ preparation, curing regimes and testing procedures to evaluate the compressive strength, the modulus of elasticity, the indirect tensile strength and the flexural strength were discussed. A compressive strength of 154.5MPa, indirect tensile strength of 11.98MPa, modulus of elasticity of 45.1GPa and flexural strength of 30.26MPa have been achieved for reinforced RPC contains 800 kg/m3 cement content and silica fume content 30% of cement weight. The test results showed some improvements by increasing cement and silica fume contentsas well as adding steel fibers on the compressive strength, modulus of elasticity and indirect tensile strength.
Źródło:
Archives of Civil Engineering; 2013, 59, 2; 175-195
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Backlash fault suppression using LQ optimal control based rst controllers in wind turbine systems using bond graphs and matlab/simulink
Autorzy:
Arab, Mohamed
Lachouri, Abederezak
Kerikeb, Mohamed
Mehennaoui, Lamine
Bouchareb, Faouzi
Powiązania:
https://bibliotekanauki.pl/articles/2115160.pdf
Data publikacji:
2021
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
modeling
bond graph
wind turbine
backlash
quadratic linear control
RST controller
Opis:
The presence of backlash in wind turbines is a source of limitations as it introduces nonlinearities that reduce their efficiency in speed/torque control which affect the performance of the power quality. Because of production tolerances during rotation, the teeth contact is lost for a small angle; until it is re-established, it produces a backlash phenomenon. The desire to eliminate this phenomenon is often hard to realise due to the nonlinear dynamic behaviour, which arises with the presence of backlash fault in a system. Therefore, the goal of this study is to develop an LQ optimal control structure in a form of an R-S-T controller in order to reduce the disturbing torque transmitted inside the dead zone of a gearbox in the wind turbine system. The actual system is also developed to be used as a demonstration model at lectures or presentations. The efficacy of the proposed control is illustrated via simulations.
Źródło:
Acta Mechanica et Automatica; 2021, 15, 3; 154--163
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Seed Emergence, Seedling Vigor Enhancement of Some Populations From Satureja Bachtiarica With Chemical, Mechanical and Physiological Treatment
Autorzy:
Alizadeh, M. A.
Arab, H.A.
Tabaie, R.
Nasiri, M.
Jafari, A.A.
Powiązania:
https://bibliotekanauki.pl/articles/2199668.pdf
Data publikacji:
2016-12-20
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Tematy:
dormancy
germination
Satureja bachtiarica
vigor
Opis:
The seeds of 3 populations from Satureja bachtiarica were collected from three native vegetation areas (Simirom2, Sharkord and Yazd). The different treatments including: cold stratification, gibberlic acid (50 and 100 ppm) Potassium nitrate (0.2 and 0.4 percent). Physical scarification (sand paper), chemical scarification (Ethylic alcohol %70) and distilled water (control) were used for breaking dormancy of the seed samples. For greenhouse experiment, the seed samples were treated with treatments and then were sown in pots using randomize design with three replications. Emergence percentage, emergence speed, length of root and shoot, seedling length, root/shoot length ratio, vigor index, seedling fresh and dry weight, dry/fresh weight ratio were evaluated during 45 days of experiment. Comparing of population Semirom2 form savory of Bachtiary was higher than other population. It was concluded that effect of gibberlic acid and potassium nitrate was higher than physical scarification and chemical scarification comparing with control.
Źródło:
Plant Breeding and Seed Science; 2016, 74; 37-44
1429-3862
2083-599X
Pojawia się w:
Plant Breeding and Seed Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prospectivity modeling of karstic groundwater using a sequential exploration approach in Tepal area, Iran
Modelowanie występowania wód gruntowych pochodzenia krasowego w regionie Tepal w Iranie metodą badania sekwencyjnego dla potrzeb prac poszukiwawczych
Autorzy:
Sharifi, F.
Arab-Amiri, A. R.
Kamkar-Rouhani, A.
Yousefi, M.
Davoodabadi-Farahani, M.
Powiązania:
https://bibliotekanauki.pl/articles/219062.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modelowanie występowania wód
badanie sekwencyjne
logika rozmyta
wody gruntowe pochodzenia krasowego
water prospectivity modeling
sequential exploration approach
fuzzy logic
karstic groundwater
Opis:
The purpose of this study is water prospectivity modeling (WPM) for recognizing karstic water-bearing zones by using analyses of geo-exploration data in Kal-Qorno valley, located in Tepal area, north of Iran. For this, a sequential exploration method applied on geo-evidential data to delineate target areas for further exploration. In this regard, two major exploration phases including regional and local scales were performed. In the first phase, indicator geological features, structures and lithological units, were used to model groundwater prospectivity as a regional scale. In this phase, for karstic WPM, fuzzy lithological and structural evidence layers were generated and combined using fuzzy operators. After generating target areas using WPM, in the second phase geophysical surveys including gravimetry and geoelectrical resistivity were carried out on the recognized high potential zones as a local scale exploration. Finally the results of geophysical analyses in the second phase were used to select suitable drilling locations to access and extract karstic groundwater in the study area.
W pracy modelowano przepływy wód gruntowych w celu rozpoznania warstw wodonośnych wód pochodzenia krasowego dla potrzeb prac poszukiwawczych, poprzez analizę danych geologicznych i poszukiwawczych z rejonu doliny Kal-Qorno w regionie Tepal, w północnej części Iranu. W oparciu o analizę sekwencyjną danych geologicznych wytyczono granice obszarów do dalszych badań poszukiwawczych. Analiza obejmuje dwa zasadnicze etapy, z uwzględnieniem skali regionalnej oraz lokalnej. W pierwszym etapie w oparciu o dane o strukturach geologicznych i właściwościach skał modelowano możliwości występowania wód w aspekcie skali regionalnej. Na tym etapie w ramach poszukiwań warstw wodonośnych pochodzenia krasowego zamodelowano warstwy struktur skalnych dowodzące występowania wód w oparciu o podejście logiki rozmytej. Po wytyczeniu obszarów docelowych, w drugim etapie badań przeprowadzono szczegółowe analizy geofizyczne z wykorzystanie grawimetrii i badań oporności geo-elektrycznej w strefach potencjalnego występowania wód, w aspekcie badania w skali lokalnej. W końcowym etapie, wyniki analiz geofizycznych otrzymane w drugim etapie procedury wykorzystane zostały do wyznaczenia miejsc wykonania odwiertów do uzyskania wód gruntowych pochodzenia krasowego w badanym terenie.
Źródło:
Archives of Mining Sciences; 2017, 62, 3; 509-530
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applying In Silico approaches for designing a chimeric InaV/N-DFPase protein and evaluating its binding with diisopropyl-fluorophosphate
Autorzy:
Allahyari, H.
Karami, A.
Tebyanian, H.
Nouri, H.R.
Khodi, S.
Farnoosh, G.
Arab, S.S.
Latifi, A.M.
Powiązania:
https://bibliotekanauki.pl/articles/11162.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Źródło:
International Letters of Natural Sciences; 2019, 75
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Patterns of Relapse Risks and Related Factors among Patients with Schizophrenia in Razi Hospital, Iran: A Latent Class Analysis
Autorzy:
Noroozi, Mehdi
Alibeigi, Neda
Armoon, Bahram
Rezaei, Omid
Sayadnasiri, Mohammad
Nejati, Somayeh
Fadaei, Farbod
Ghahestany, Davood Arab
Dieji, Bahman
Ahounbar, Elahe
Powiązania:
https://bibliotekanauki.pl/articles/2127857.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Razi Hospital
Iran
Relapse Risks
Patients
Schizophrenia
Latent Class Analysis
Opis:
Objectives: Relapse is very much associated with the management of disorder during the treatment, but also many other factors could trigger it. The aim of this study was to explore classes and patterns of relapse risk in patients with schizophrenia of Razi Hospital. Methods: Using random sampling techniques, we recruited 300 participants with a diagnosis of schizophrenia in Razi hospital of Tehran (Iran) between January and May 2017 in a cross-sectional survey. We used latent class analysis (LCA) to establish a baseline model of risk profiles and to identify the optimal number of latent classes, and we used ordinal regression to identify factors associated with class membership. Results: Three classes of multiple relapse risk were identified. LCA showed that, overall, 52%, 22% and 26% of participants with schizophrenia were divided into class 1, class 2 and class 3, respectively. Compared to members in the lowest-risk class (reference group), the highest-risk class members had higher odds of being the age of disorder onset under 25 (OR = 1.4; CI: 1.42–2.33). Participants with schizophrenia who were unemployed were more likely to categorize in the highest-risk class than members of the low-risk class (OR = 2.5; CI: 1.44–4.1). Also, female patients were more likely to belong to members of the high-risk class than members of the low-risk class (OR = 2.22; CI: 1.74–7.64). Conclusion: These findings emphasize the importance of having targeted prevention programs for all domains of Age of onset, female and unemployed related. So, current study suggested that interventions should focus on these risk factors. Furthermore, Increasing the Job opportunities for participants with schizophrenia is warranted so as to prevent of schizophrenia disorder.
Źródło:
Polish Psychological Bulletin; 2018, 49, 3; 355-359
0079-2993
Pojawia się w:
Polish Psychological Bulletin
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-14 z 14

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