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Wyszukujesz frazę "Ranjbar, M." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
A new empirical correlation for estimating bubble point pressure using the genetic algorithm
Autorzy:
Heidarian, M.
Karimnezhad, M.
Schaffie, M.
Ranjbar, M.
Powiązania:
https://bibliotekanauki.pl/articles/184188.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
bubble point pressure
empirical correlations
Middle East
genetic algorithm
PVT properties
Opis:
In this paper, a new and more accurate correlation to predict bubble point pressure (Pb) for Middle East crudes by using the genetic algorithm (GA) is attempted. For this purpose, a total of 286 data sets of different crude oils from Middle East reservoirs were used as training data for constructing the correlation. The general form of the correlation was found by several regressive examinations. To improve the correlation, the genetic algorithm was applied. To validate the correlation, 143 data sets of different crudes from Middle East reservoirs which were different from the training data were used as test data for calculating mean absolute relative error (MARE) and correlation coefficient (R2) between the predicted values from the proposed correlation and the experimental values. In addition, the MARE and R2 were calculated for previous correlation in the test data. The results show that the proposed correlation is more accurate than all of the previous correlations exclusively for Middle East crudes.
Źródło:
Geology, Geophysics and Environment; 2017, 43, 1; 33-41
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of higher mode effects and lateral load patterns in pushover analysis of steel frames with steel shear wall
Autorzy:
Ghanoonibagha, M.
Gol, M. R. A.
Ranjbar, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/102543.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
load patterns
steel shear wall
static nonlinear
dynamic nonlinear
Opis:
When an earthquake occurs, the structure will enter into a nonlinear stage; therefore, new approaches based on nonlinear analysis are needed to flourish with the purpose of more realistic investigations on seismic behavior and destruction mechanism of structures. According to the modern philosophy, “Performance-based Earthquake Engineering” is formed in which simple nonlinear static analyses are mostly used in order to determine the structure’s behavior in nonlinear stage. This method assumes that the structure response is only controlled by the main mode and the shape of this mode will remain the same, while it enters the nonlinear stage. Both of these assumptions are approximations, especially in high buildings, which have a long period. It seems that constant load pattern used in these methods cannot consider all of the effects properly. In this paper, an attempt was made to study the accuracy of these methods in comparison to nonlinear dynamic analysis, by considering various load patterns existing in FEMA, also load patterns proportional to higher modes in nonlinear static method, and employing an approximative method of MPA modal analysis, study the accuracy of these methods in comparison to nonlinear dynamic analysis. For this purpose, three steel frames of 4, 8, and 12-stories with steel shear wall have been studied.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 29; 13-27
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of compressed heat exchanger efficiency by using genetic algorithm
Autorzy:
Ghorbani, M.
Ranjbar, S. F.
Powiązania:
https://bibliotekanauki.pl/articles/266267.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
wymiennik ciepła
spadek ciśnienia
pojemność cieplna
optymalizacja
algorytm genetyczny
heat exchanger
pressure drop
heat capacity
optimization
genetic algorithm
Opis:
Due to the application of coil-shaped coils in a compressed gas flow exchanger and water pipe flow in airconditioner devices, air conditioning and refrigeration systems, both industrial and domestic, need to be optimized to improve exchange capacity of heat exchangers by reducing the pressure drop. Today, due to the reduction of fossil fuel resources and the importance of optimal use of resources, optimization of thermal, mechanical and electrical devices has gained particular importance. Compressed heat exchangers are the devices used in industries, especially oil and petrochemical ones, as well as in power plants. So, in this paper we try to optimize compressed heat exchangers. Variables of the functions or state-of-the-machine parameters are optimized in compressed heat exchangers to achieve maximum thermal efficiency. To do this, it is necessary to provide equations and functions of the compressed heat exchanger relative to the functional variables and then to formulate the parameter for the gas pressure drop of the gas flow through the blades and the heat exchange surface in relation to the heat duty. The heat transfer rate to the gas-side pressure drop is maximized by solving the binary equation system in the genetic algorithm. The results show that using optimization, the heat capacity and the efficiency of the heat exchanger improved by 15% and the pressure drop along the path significantly decreases.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 461-472
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: an incubation study
Autorzy:
Jalali, M.
Lotf, M.S.
Ranjbar, F.
Powiązania:
https://bibliotekanauki.pl/articles/971127.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
salinity
sodicity
agricultural residues
bioremediation
incubation
Opis:
Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evalu- ate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treat- ed soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO 3 -) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incuba- tion. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) >12.7% (canola residue-treated soil) >11.1% (wheat residue-treated soil) >9.6% (sunflower residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the appli- cation of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition.
Źródło:
Polish Journal of Soil Science; 2020, 53, 1
0079-2985
Pojawia się w:
Polish Journal of Soil Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the dose enhancement factor of high intensity low mono-energetic X-ray radiation with labeled tissues by gold nanoparticles
Autorzy:
Ranjbar, H.
Shamsaei, M.
Ghasemi, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/148638.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiation therapy
energy optimization
dose enhancement factor
dose absorption
gold nanoparticles
MCNPX code
Opis:
The aim of radiotherapy is to maximize the dose applied to the tumor while keeping the dose to the surrounding healthy tissue as low as possible. To further enhance dose to a tumor, techniques to radiosensitization of the tumor, using high atomic number elements, have been proposed. The aim of this study was to investigate the influence of using gold nanoparticles as a contrast agent on tumor dose enhancement when the tissue is irradiated by a typical mono energy X-ray beam. To improve the conventional radiotherapy enhancement of the absorbed dose in a tumor tissue and to spare the skin and normal tissues during irradiation in the presence of concentration agent, a model based on a Monte Carlo N-Particle eXtended (MCNPX) computer code has been designed to simulate the depth dose in a phantom containing an assumed tumor. Test was carried out in two phases. In phase 1, verification of this model using the MCNPX was evaluated by comparing the obtained results with those of the published reports. In phase 2, gold was introduced into assumed tumor inside the phantom at different depths in the simulation program. Simulation was performed for four different concentrations of gold nanoparticles using a low mono-energetic parallel beam of synchrotron radiation. The obtained results show that the optimum energy for dose enhancement is found to be around 83–90 keV for all gold concentrations. The dose enhancement factor is increased linearly with concentration and diminished in depth along the central beam in the tumor. This approach of introducing contrast agents in conventional radiotherapy could hopefully prepare new treatment planning and improve the efficiency of tumor therapy.
Źródło:
Nukleonika; 2010, 55, 3; 307-312
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of blood flow rheology using second-grade viscoelastic model (Phan-Thien–Tanner) within carotid artery
Autorzy:
Ramiar, A.
Larimi, M. M.
Ranjbar, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/307522.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tętnica szyjna
model lepkoplastyczny
przepływ pulsujący
naprężenie ścinające
OpenFOAM
carotid artery
viscoelastic model
pulsatile flow
shear stress
Opis:
Purpose: Hemodynamic factors, such as Wall Shear Stress (WSS), play a substantial role in arterial diseases. In the larger arteries, such as the carotid artery, interaction between the vessel wall and blood flow affects the distribution of hemodynamic factors. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a second-grade viscoelastic fluid and the effects of viscoelastic on blood flow in carotid artery is investigated. Methods: Pulsatile flow studies were carried out in a 3D model of carotid artery. The governing equations were solved using finite volume C++ based on open source code, OpenFOAM. To describe blood flow, conservation of mass and momentum, a constitutive relation of simplified Phan-Thien–Tanner (sPTT), and appropriate relations were used to explain shear thinning behavior. Results: The first recirculation was observed at t = 0.2 s, in deceleration phase. In the acceleration phase from t = 0.3 s to t = 0.5 s, vortex and recirculation sizes in bulb regions in both ECA and ICA gradually increased. As is observed in the line graphs based on extracted data from ICA, at t = 0.2 s, τyy is the maximum amount of wall shear stress and τxy the minimum one. The maximum shear stress occurred in the inner side of the main branch (inner side of ICA and ECA) because the velocity of blood flow in the inner side of the bulb region was maximum due to the created recirculation zone in the opposite side in this area. Conclusions: The rheology of blood flow and shear stress in various important parts (the area that are in higher rates of WSS such as bifurcation region and the regions after bulb areas in both branches, Line1–4 in Fig. 7) were also analyzed. The investigation of velocity stream line, velocity profile and shear stress in various sections of carotid artery showed that the maximum shear stress occurred in acceleration phase and in the bifurcation region between ECA and ICA which is due to velocity gradients and changes in thinning behavior of blood and increasing strain rate in Newtonian stress part.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 3; 27-41
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidative toxic stress and p53 level in healthy subjects occupationally exposed to outdoor air Pollution – a cross-sectional study in Iran
Autorzy:
Vandchali, N.R.
Koolivand, A.
Ranjbar, A.
Zarei, P.
Fathi, M.
Malekafzali, S.
Mollamohammadi, N.
Jalali-Mashayekhi, F.
Powiązania:
https://bibliotekanauki.pl/articles/28762963.pdf
Data publikacji:
2020
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2020, 27, 4; 585-590
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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