检索结果-南通市图书馆

International Journal of Minerals,Metallurgy and Materials 2019年第8期26卷 1005-1012页

作者： ghasem Jamali Salman Nourouzi Roohollah Jamaati Department of Materials engineering Babol Noshirvani University of Technology

In the present work,the friction stir back extrusion(FSBe)process was used as a novel method for the fabrication of AA6063 aluminum alloy *** electron microscopy(SeM)equipped with energy dispersive spectroscopy(eDS),tensile and hardness tests were *** FSBe via the rotational speed of 475 r/min resulted in fine equiaxed grains,and the mean grain size decreased from 179.0μm to 15.5μm due to the occurrence of dynamic recrystallization(DRX).Heat generated by the FSBe changed the size and volume fraction of the Mg2Si precipitated *** minimum particle size and maximum volume fraction obtained in the sample were processed by rotational speeds of 475 and 600 r/min,*** 475-r/min sample had the maximum hardness value due to having the lowest grain size(i.e.,15.5μm)and the presence of many fine Mg2Si precipitates in the aluminum *** increasing rotational speed up to 600 r/min,the hardness decreased,owing to the growth of both grains and *** FSBe process with a rotational speed of 475 r/min increased the tensile strength(from 150 to 209 MPa)and ductility(from 21.0%to 30.2%)simultaneously.

关键词： aluminum alloys friction stir back extrusion microstructure mechanical properties

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2013年第4期7卷 446-455页

作者： Mehdi VeISKARAMI ghasem HABIBAGAHI Civil engineering Department Faculty of EngineeringUniversity of GuilanRasht P.O.41635-3756Iran Civil and environmental engineering Department School of EngineeringShiraz UniversityShiraz P.O.71334-1585Iran

An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been *** kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing *** smooth and rough base strip foundations were considered associated with different collapse *** of the groundwater flow leads to a non-symmetric collapse pattern,i.e.,a weak side and a strong side in twosided collapse patterns,depending on the direction of the *** was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence,a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词： foundation bearing capacity limit analysis numerical computation plasticity seepage

New CCD photometric investigation of high amplitude δ Scuti star V2455 Cyg

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第7期20卷 134-138页

作者： Setareh Ostadnezhad ghasem Forozani Mohammad Ghanaatian Department of Physics Payame Noor University(PNU) P.O. Box 19395-3697 Tehran Iran

New V-band CCD observations of variable star V2455 Cyg were performed during two nights in September 2017. According to all times of maximum light and new maxima, the O-C curve was *** period changes of V2455 Cyg were investigated and the rate of increasing period was obtained to be(1/P) d P/dt = 1.99 × 10^-7 yr-1. Frequency analysis indicated that V2455 Cyg pulsates with the radial p mode and the fundamental frequency is 10.61574 d-1. Physical parameters of V2455 Cyg at mean temperature were determined(e.g., R = 2.52 R⊙and M = 1.92 M⊙). The position of this star in the H-R diagram confirms that V2455 Cyg is a high amplitude δ Scuti star.

关键词： techniques:photometric stars:variables:δScuti stars:individual(V2455 Cyg)

Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent: equilibrium and dynamic studies

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2019年第2期16卷 417-427页

作者： ghasem Bakhtiari Hamid Ghassabzadeh Sayed Javid Royaee Majid Abdouss Mansour Bazmi Chemistry Department Amirkabir University of Technology Refining Technology Development Division Research Institute of Petroleum Industry

This paper summarizes the results of a study of adsorption of sulfur compounds from a high-sulfur feed on improved spherical-shaped nano-AgX zeolite. For this purpose, the nano-AgX zeolite was initially synthesized and improved with silver compounds such as silver nitrate, and then it was utilized in the adsorption process. In order to investigate the equilibrium and dynamics of the adsorption process, adsorptive desulfurization of real feed(i.e., sour gas condensate from the South Pars gas field) was carried out in batch and continuous processes under several operating conditions; a temperature-dependent Langmuir isotherm model was used to fit the equilibrium data. The value of monolayer adsorption capacity(q_m) and adsorption enthalpy(ΔH) were calculated to be 1.044 mmol/g and 16.8 kJ/mol, respectively. Furthermore, a detailed theoretical model was employed in order to model the breakthrough experiments. The results revealed that an increase in the feed flow rate and 1/T values will cause linear and exponential increase in the total mass transfer coefficient(ks). Isotherm and dynamic breakthrough models were found to be in agreement with the experimental data.

关键词： Process design Desulfurization Dynamic adsorption Gas condensate equilibrium

estimation of rock uniaxial compressive strength for an Iranian carbonate oil reservoir: Modeling vs. artificial neural network application

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2018年第4期3卷 336-345页

作者： Maryam Hassanvand Siyamak Moradi Moslem Fattahi ghasem Zargar Mosayyeb Kamari Department of Petroleum engineering Abadan Faculty of Petroleum EngineeringPetroleum University of TechnologyAbadanIran Department of Chemical engineering Abadan Faculty of Petroleum EngineeringPetroleum University of TechnologyAbadanIran National Iranian South Oil Company AhvazIran

estimation of rock mechanic parameters is an important issue in reservoir *** compressive strength(UCS)and elastic modulus are the most important factors in determining the rock mechanic parameters in petroleum engineering *** to the parameters in fields such as designing fracture,analyzing of wellbore stability and drilling programming are very *** most accurate method to assign the aforementioned parameters is measuring these parameters in a *** determination of these parameters is problematic work due to technology issues,lack of laboratory equipment and coring problems in oil and gas wells,so indirect estimation of these parameters is *** well log data is the cheapest and most available approach in order to indirectly estimate these *** this investigation,different models including multiple linear regression(MLR)and artificial neural network(ANN)(i.e.,multi linear perceptron(MLP)and radial basis function(RBF))were utilized for prediction of UCS via the three parameters of porosity,density and water *** data were obtained from analysis of sonic,neutron,gamma ray and electric *** best results were obtained from a 3-15-1 MLP network which included one hidden layer and 15 neurons from the hidden layer using the trial and error method,and a 3-17-1 RBF which included 17 hidden neurons and a spread ò of *** core data from one of the carbonate Iranian oil fields(Asmari reservoir)were utilized for training,validation and testing of the networks,and correlation coefficients of 0.68,0.90 and 0.83 were obtained for MLR,MLP and RBF,respectively.

关键词： Uniaxial compressive strength Artificial neural network Porosity Linear regression Water saturation

Prediction of asphaltene precipitation using support vector regression tuned with genetic algorithms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum 2016年第3期2卷 301-306页

作者： Mohammad Ghorbani ghasem Zargar Hooshang Jazayeri-Rad Department of Petroleum engineering Petroleum University of Technology(PUT)AhwazIran Department of Instrumentation and Automation Petroleum University of Technology(PUT)AhwazIran

Due to the severe and costly problems caused by asphaltene precipitation in petroleum industry,developing a quick and accurate model,to predict the asphaltene precipitation under different conditions,seems *** this study,a new model,namely genetic algorithm e support vector regression(GA-SVR)is proposed,which is applied to predict the amount of asphaltene *** is used to select the best optimal values of SVR parameters and kernel parameter,simultaneously,to increase the generalization performance of the *** GA-SVR model is trained and tested on the experimental data sets reported in *** performance of the GASVR model is compared with two scaling equation models,using statistical error measures and graphical *** results show that the prediction performance of the proposed model,is highly reliable and satisfactory.

关键词： Asphaltene precipitation Prediction Support Vector Regression(SVR) Genetic Algorithm(GA) Parameter optimization

Predicting COVID-19 fatality rate based on age group using LSTM

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2021年第12期14卷 564-574页

作者： Zahra Ramezani Seyed Abbas Mousavi ghasem Oveis Mohammad Reza Parsai Fatemeh Abdollahi Jamshid Yazdani Charati Department of epidemiology and Biostatistics School of HealthMazandaran University of Medical SciencesSariIran Department of Psychiatry Psychiatry and Behavioral Sciences Research CenterAddiction InstituteMazandaranUniversity of Medical SciencesSariIran Health vice-chancellor of Mazandaran University of Medical Sciences SariIran Control Disease Center Mazandaran University of Medical SciencesSariIran Department of Public Health Psychiatry and Behavioral Sciences Research CenterMazandaran University of Medical SciencesSariIran

Objective: To predict the daily incidence and fatality rates based on long short-term memory(LSTM) in 4 age groups of COVID-19 patients in Mazandaran Province, ***: To predict the daily incidence and fatality rates by age groups, this epidemiological study was conducted based on the LSTM model. All data of COVID-19 disease were collected daily for training the LSTM model from February 22, 2020 to April 10, 2021 in the Mazandaran University of Medical Sciences. We defined 4 age groups, i.e., patients under 29, between 30 and 49, between 50 and 59, and over 60 years old. Then, LSTM models were applied to predict the trend of daily incidence and fatality rates from 14 to 40 days in different age groups. The results of different methods were compared with each ***: This study evaluated 5 0826 patients and 5 109 deaths with COVID-19 daily in 20 cities of Mazandaran Province. Among the patients, 25 240 were females(49.7%), and 25 586 were males(50.3%). The predicted daily incidence rates on April 11, 2021 were 91.76, 155.84, 150.03, and 325.99 per 100 000 people, respectively;for the fourteenth day April 24, 2021, the predicted daily incidence rates were 35.91, 92.90, 83.74, and 225.68 in each group per 100 000 people. Furthermore, the predicted average daily incidence rates in 40 days for the 4 age groups were 34.25, 95.68, 76.43, and 210.80 per 100 000 people, and the daily fatality rates were 8.38, 4.18, 3.40, 22.53 per 100 000 people according to the established LSTM model. The findings demonstrated the daily incidence and fatality rates of 417.16 and 38.49 per 100 000 people for all age groups over the next 40 days. Conclusions: The results highlighted the proper performance of the LSTM model for predicting the daily incidence and fatality rates. It can clarify the path of spread or decline of the COVID-19 outbreak and the priority of vaccination in age groups.

关键词： COVID-19 Long short-term memory model Incidence rate Fatality rate Prediction Age classification

Biozonation and Paleobathymetry on Foraminifera Upper Cretaceous Deposites of Central Iran Basins (Isfahan, Baharestan Section)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Geology 2014年第8期4卷 343-353页

作者： Bita ghasem Shirazi Lida Bakhshandeh Abdollah Yazdi Department of Geology Kahnooj Branch Islamic Azad University Kerman Iran Department of Geology Science and Research Branch Islamic Azad University Tehran Iran

In this study Late Cretaceous stratum in central Iran, Baharestan section in Isfahan area, was evaluated by biozonation and paleobathymetry.?These sediments have 89 meters thick, and strata have been formed of marl and marl limestone. In order to indicate the ancient depth of Upper Cretaceous at this time, planktonic and benthic foraminifera were studied. The percentage of the total planktonic foraminifera to the whole sample of foraminifera after the removal of indwell benthic foraminifera (%P*) using the formula?D?=?e(3.58718 + (0.03534?×?%P*))?was identified and depth of 200 - 450 meters was achieved for them. In the present investigation, 30 planktonic species of 11 genus have been identified. The Upper Cretaceous deposit was divided to 6 biozones on the basis of planktonic foraminifera which are cosmopolitan and consist of: Biozone 1—Marginotruncana sigali-Dicarinella primitiva?partial range zone;?Biozone 2—Dicarinella concavata?interval zone;?Biozone 3—Dicarinella asymetrica?total range zone;Biozone 4—Globotruncanita elevata?partial range zone;Biozone 5—Globotruncana ventricosa?interval zone;Biozone 6—Radotruncana calcarata?interval zone.?Based on planktonic foraminifera, the Upper Cretaceous sediments in the study area are of the Turonian-Late Campanian ages.

关键词： Biozonation Foraminifera Central Iran Paleobathymetry Turonian Late Campanian

Oral Desmopressin in the Management of Adults with Nocturia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Urology 2011年第4期1卷 72-75页

作者： Shahram Gooran Sevil Nasirmohtaram Mohammad ghasem Mohseni Behzad Narouie 不详

We investigated the efficacy of oral desmopressin in the treatment of adult nocturia. In an analytical study between 2007-2009 in Zahedan-Iran, Thirty patients ≥55 years with verified nocturia (≥two voids/night) were enrolled. Patients with a history of an obstructive cause of nocturia, those with diseases getting worse by the anti-diuretic affect of desmopressin and those with well-defined curable causes (e.g. cystitis) were excluded. Patients received 0.2 mg of oral desmopressin at bed time for a period of 3 weeks. p en as the significant level. All 30 patients enrolled completed the trial. Fourteen (47 %) patients receiving desmopressin had fewer than half the number of nocturnal voids relative to base line (p e mean number of nocturnal voids decreased from 4.6 to 2.4 (p e (10%), headache (3%) and dizziness (3%) were reported. All adverse events were of mild intensity and there were no instances of hyponatremia. Oral desmopressin is an effective treatment in patients with nocturia and is well-tolerated.

关键词： Nocturia Desmopressin Arginine Vasopressin