This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditi...This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditional methods like blow-down and co-production have limitations, including sand production, water coning, and inefficiency in strong aquifers. To overcome these issues, this research explores CO2 injection near the edge aquifer, aiming to reduce water influx and enhance gas recovery through the propagation of a CO2 plume in the gas-water contact zone. Both synthetic and real compositional reservoir models were studied, with CO2 injection performed while maintaining reservoir pressure below 90% of the initial level. Results show that CO2 sequestration significantly improved recovery, particularly in higher permeability reservoirs, where it reduced aquifer influx and increased gas production by 26% under challenging conditions. While CO2 dissolution in water decreased aquifer influx by 39%, its adverse effect on sweep efficiency led to a reduction in gas and water production by 4.2% and 10%, respectively. The method's effectiveness was not significantly impacted by aquifer permeability, but it was sensitive to vertical-to-horizontal permeability ratios. When applied to a real gas reservoir, the proposed method increased gas production by 14% compared to conventional techniques, with minimal CO2 production over a 112-year period. This study demonstrates the potential of CO2 sequestration as a comprehensive solution for enhancing gas recovery, reducing water production, and mitigating environmental impacts in water-drive gas reservoirs.展开更多
Objective:To determine brucellosis's epidemiologic,laboratory,diagnostic and public health features considering brucellosis is endemic in Azna County,western Iran.Methods:This descriptive cross-sectional study was...Objective:To determine brucellosis's epidemiologic,laboratory,diagnostic and public health features considering brucellosis is endemic in Azna County,western Iran.Methods:This descriptive cross-sectional study was investigated on 43 patients with brucellosis in Azna County. The subjects were the patients with symptoms correspondent with brucellosis and positive Wright and 2ME tests. A questionnaire about demographic,epidemiological and laboratory findings was filled in. Afterwards,patients were treated using usual antimicrobial drugs regimen. The collected data were analyzed by SPSS software version 16.Results:Forty-three subjects were found to be positive in laboratory tests. Incidence of Brucellosis was 59.31 per hundred thousand population. About 34.9% of patients were female and 65.1%male. Nearly 95.2% of human cases were living in rural and 4.8%in urban areas. Around 20.9%of patients had history of animal contact. The commonest transmission was unpasteurized dairy products(79.1%). The most contagious seasons were summer and spring(60.3%). The most common age group was 15-24(27.9%),and about 60.5%of the patients were between 15-44 years old. Disease was more common among housewives(30.2%) and farmers(20.9%). The majority of the patients had Wright test titre=1:320(54.1%) and 2ME test titre=1:160(56.1%) in serological titration.Doxycycline with Rifampin was used for treatment of the greatest of patients(60.4%).Conclusions:In order to control this zoonotic disease,close cooperation of health and veterinary organizations is necessary.展开更多
In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were...In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, inductively coupled plasma atomic emission spectrometer （ICP-AES）, temperature programmed reduction （H2-TPR）, CO chemisorption, energy dispersive X-ray （EDX） and scanning electron microscopy （SEM） techniques. Kinetic properties of all catalysts were investigated in a batch re- actor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/AlzO3 catalyst enhances its activity as compared to Fe/AlaO3. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/AlzO3 catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fez（MoO4）3 phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fez（MoO4）3 phase has low reducibility, therefore the Fe2（MoO4）3 phase significantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al2O3 catalyst. Overall, this study introduces Fe-Mo/Al2O3 as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.展开更多
AIM: To study the loss of heterozygosity (LOH) at 8p21-23 locus in diffuse gastric cancer.METHODS: To evaluate the involvement of this region in gastric cancer, we used eight microsatellite markers covering two Mb of ...AIM: To study the loss of heterozygosity (LOH) at 8p21-23 locus in diffuse gastric cancer.METHODS: To evaluate the involvement of this region in gastric cancer, we used eight microsatellite markers covering two Mb of mentioned region, to perform a high-resolution analysis of allele loss in 42 cases of late diffuse gastric adenocarcinoma.RESULTS: Six of these STS makers: D8S1149, D8S1645, D8S1643, D8S1508, D8S1591, and D8S1145 showed 36%, 28%, 37%, 41%, 44% and 53% LOH, respectively.CONCLUSION: A critical region of loss, close to the NAT2 locus and relatively far from FEZ1 gene currently postulated as tumor suppressor gene in this region.展开更多
Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz...Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.展开更多
【目的】蛀茎夜蛾Sesamia spp.是伊朗和其他国家(包括印度、巴基斯坦、斯里兰卡和日本)甘蔗上最具破坏性的害虫。蛀茎夜蛾幼虫钻蛀茎秆,对茎秆产生为害,降低重量和含糖量并降低甘蔗汁品质。应用抗性品种是一种有效的工具,对环境无不利...【目的】蛀茎夜蛾Sesamia spp.是伊朗和其他国家(包括印度、巴基斯坦、斯里兰卡和日本)甘蔗上最具破坏性的害虫。蛀茎夜蛾幼虫钻蛀茎秆,对茎秆产生为害,降低重量和含糖量并降低甘蔗汁品质。应用抗性品种是一种有效的工具,对环境无不利影响。本研究旨在评价甘蔗商业品种对蛀茎夜蛾的抗性。【方法】在伊朗Ahwaz的Salman-Farsi Agro-industry Farms于2013-2014和2014-2015两个连续年份,采用随机区组设计进行5次重复试验。应用了CP69-1062,CP48-103,CP57-614,CP73-21,SP70-1143,IRC99-01,IRC99-02和L62-96 8个品种。在收获前,随机取20株完整的甘蔗茎秆进行蛀茎夜蛾的为害评估。记录受害茎秆百分比、被钻蛀的节间百分比(percent of internodes bored,IB)、出口孔的数目、活的蛀茎夜蛾的数目、每品种每公顷面积中蛾的繁殖量(moth production per hectare of each variety,MP)。【结果】各测定参数在品种间均存在显著差异。从被钻蛀的节间百分比和蛾的繁殖指数判断,L62-96是最敏感的品种(2014年:14.58%IB,95 200 MP/ha;2015年:16.76%IB和111 300 MP/ha),其次是CP69-1062和CP48-103;CP57-614是这两年中抗性最强的品种(2014年:1.24%IB,8 400 MP/ha;2015年:1.02%IB,7 000 MP/ha)。【结论】建议限制敏感品种的栽培,并应用其他控制措施,结合品种抗性,以治理敏感品种中的蛀茎夜蛾。展开更多
Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engine...Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engineering calculations.The experimental measurements,Equations of State （EoS） and empirical correlations are the most common sources of z-Factor calculations.There are more than twenty correlations available with two variables for calculating the z-Factor from fitting in an EoS or just through fitting techniques.However,these correlations are too complex,which require initial value and more complicated and longer computations or have magnitude error.The purpose of this study is to develop a new accurate correlation to rapidly estimate z-Factor.Result of this correlation is compared with large scale of database and experimental data also.Proposed correlation has 1.660 of Absolute Percent Relative Error （EABS） versus Standing and Katz chart and has also 3.221 of EABS versus experimental data.The output of this correlation can be directly assumed or be used as an initial value of other implicit correlations.This correlation is valid for gas coefficient of isothermal compressibility （cg） calculations also.展开更多
Determining the rate of asphaltene particle growth is one of the main problems in modeling of asphaltene precipitation and deposition.In this paper,the kinetics of asphaltene aggregation under different precipitant co...Determining the rate of asphaltene particle growth is one of the main problems in modeling of asphaltene precipitation and deposition.In this paper,the kinetics of asphaltene aggregation under different precipitant concentrations have been studied.The image processing method was performed on the digital photographs that were taken by a microscope as a function of time to determine the asphaltene aggregation growth mechanisms.The results of image processing by MATLAB software revealed that the growth of asphaltene aggregates is strongly a function of time.Different regions could be recognized during asphaltene particle growth including reaction-and diffusion-limited aggregation followed by reaching the maximum asphaltene aggregate size and start of asphaltene settling and the final equilibrium.Modeling has been carried out to predict the growth of asphaltene particle size based on the fractal theory.General equations have been developed for kinetics of asphaltene aggregation for reaction-limited aggregation and diffusion-limited aggregation.The maximum size of asphaltene aggregates and settling time were modeled by using force balance,acting on asphaltene particles.Results of modeling show a good agreement between laboratory measurements and model calculations.展开更多
ObjectiveTo evaluate the antibacterial effect and physicochemical properties of essential oil of Zataria multiflora Boiss.MethodsAntibacterial activity of essential oil of Zataria multiflora Boiss was assessed by agar...ObjectiveTo evaluate the antibacterial effect and physicochemical properties of essential oil of Zataria multiflora Boiss.MethodsAntibacterial activity of essential oil of Zataria multiflora Boiss was assessed by agar disc diffusion and minimal inhibitory concentration(MIC) was tested by E test.ResultsThe essential oil of Zataria multiflora Boiss was effective on pathogenic bacteria particularly Staphylococcus aureus (S. aureus). The MIC values of the target cultures ranged from 0.39 mg/mL to 1.56 mg/mL. The physicochemical properties like effects of pH, temperature, detergents, and enzymes on the activity of essential oil from Zataria multiflora Boiss were also determined. The essential oil was quite stable to temperature as tested against S. aureus and Escherichia coli (E. coli). The essential oil was very stable over a wide range of pH. The antibacterial activity of essential oil was insensitive to various protein-denaturing detergents (Such as Tween 80, Tween 20, Triton 100, etc.) and enzymes (namely proteinase K, trypsin, lipase, and lysosyme).ConclusionsA potential use of the essential oil from Zataria multiflora Boiss is suggested. More studies including further purification, mass spectra, nuclear magnetic resonance (NMR) and evaluation of toxicity are needed for confirmation of this suggestion.展开更多
An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructur...An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that a-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.展开更多
Nanofluids and low-salinity water(LSW)flooding are two novel techniques for enhanced oil recovery.Despite some efforts on investigating benefits of each method,the pros and cons of their combined application need to b...Nanofluids and low-salinity water(LSW)flooding are two novel techniques for enhanced oil recovery.Despite some efforts on investigating benefits of each method,the pros and cons of their combined application need to be evaluated.This work sheds light on performance of LSW augmented with nanoparticles through examining wettability alteration and the amount of incremental oil recovery during the displacement process.To this end,nanofluids were prepared by dispersing silica nanoparticles(0.1 wt%,0.25 wt%,0.5 wt% and 0.75 wt%)in 2,10,20 and 100 times diluted samples of Persian Gulf seawater.Contact angle measurements revealed a crucial role of temperature,where no wettability alteration occurred up to 80 ℃.Also,an optimum wettability state(with contact angle 22°)was detected with a 20 times diluted sample of seawater augmented with 0.25 wt% silica nanoparticles.Also,extreme dilution(herein 100 times)will be of no significance.Throughout micromodel flooding,it was found that in an oil-wet condition,a combination of silica nanoparticles dispersed in 20 times diluted brine had the highest displacement efficiency compared to silica nanofluids prepared with deionized water.Finally,by comparing oil recoveries in both water-and oil-wet micromodels,it was concluded that nanoparticles could enhance applicability of LSW via strengthening wettability alteration toward a favorable state and improving the sweep efficiency.展开更多
In recent years, there has been an increase of interest in the flow of gases at relatively high pressures and high temperatures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well ...In recent years, there has been an increase of interest in the flow of gases at relatively high pressures and high temperatures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well as through the porous media constituting natural petroleum reservoirs, requires knowledge of the viscosity of the fluid at the pressure and temperature involved. Although there are numerous publications concerning the viscosity of methane at atmospheric pressure, there appears to be little information available relating to the effect of pressure and temperature upon the viscosity. A survey of the literature reveals that the disagreements between published data on the viscosity of methane are common and that most investigations have been conducted over restricted temperature and pressure ranges. Experimental viscosity data for methane are presented for temperatures from 320 to 400 K and pressures from 3000 to 140000 kPa by using falling body viscometer. A summary is given to evaluate the available data for methane, and a comparison is presented for that data common to the experimental range reported in this paper. A new and reliable correlation for methane gas viscosity is presented. Predicted values are given for temperatures up to 400 K and pressures up to 140000 kPa with Average Absolute Percent Relative Error （EABS） of 0.794.展开更多
Rock typing is an important tool in evaluation and performance prediction of reservoirs.Different techniques such as flow zone indicator(FZI),FZI~*and Winland methods are used to categorize reservoir rocks into distin...Rock typing is an important tool in evaluation and performance prediction of reservoirs.Different techniques such as flow zone indicator(FZI),FZI~*and Winland methods are used to categorize reservoir rocks into distinct rock types.Generally,these methods are applied to petrophysical data that are measured at a pressure other than reservoir pressure.Since the pressure changes the pore structure of rock,the effect of overburden pressure on rock typing should be considered.In this study,porosity and permeability of 113 core samples were measured at five different pressures.To investigate the effect of pressure on determination of rock types,FZI,FZI~*and Winland methods were applied.Results indicated that although most of the samples remain in the same rock type when pressure changes,some of them show different trends.These are related to the mineralogy and changes in pore system of the samples due to pressure change.Additionally,the number of rock types increases with increasing pressure.Furthermore,the effect of overburden pressure on determination of rock types is more clearly observed in the Winland and FZI~*methods.Also,results revealed that a more precise reservoir dynamic simulation can be obtained by considering the reservoir rock typing process at reservoir conditions.展开更多
This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni...This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.展开更多
Knowing the current condition of the faults and fractures in a reservoir is crucial for production and injection activities.A good estimation of the fault reactivation potential in the current stress field is a useful...Knowing the current condition of the faults and fractures in a reservoir is crucial for production and injection activities.A good estimation of the fault reactivation potential in the current stress field is a useful tool for locating the appropriate spot to drill injection wells and to calculate the maximum sustainable pore pressure in enhanced oil recovery and geosequestration projects.In this study,after specifying the current stress state in the Gachsaran oilfield based on Anderson’s faulting theory,the reactivation tendency of four faults(F1,F2,F3,and F4)in the Asmari reservoir is analyzed using 3D Mohr diagrams and slip tendency factors.Results showed that all the faults are stable in the current stress state,and F2 has the potential to undergo the highest pore pressure build-up in the field.On the other hand,F3 has the proper conditions(i.e.,strike and dip referring to σHmax orientation)for reactivation.Stress polygons were also applied to show the effect of the pore pressure increase on fault stability,in a graphical manner.According to the results,the best location for drilling a new injection well in this part of the field is the NW side of F2,due to the lower risk of reactivation.It was found that both methods of 3D Mohr diagrams and slip tendency factors predict similar results,and with the lack of image logs for stress orientation determination,the slip tendency method can be applied.The results of such studies can also be used for locating safe injection points and determining the injection pressure prior to numerical modeling in further geomechanical studies.展开更多
AIM：To evaluate possible risk factors for the spread of hepatitis C infection and to analyze the characteristics of the epidemiological and clinical patterns among the patients with hepatitis C infection. METHODS： D...AIM：To evaluate possible risk factors for the spread of hepatitis C infection and to analyze the characteristics of the epidemiological and clinical patterns among the patients with hepatitis C infection. METHODS： During a five-year period a cross-sectional study was conducted among HCV positive individuals referred to the Ahwaz JundiShapour University Hospitals （AJSUH） and Hepatitis Clinic from 1 Sept 1999 to 1 Sept 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion organization. Enzyme-linked immunosorbent assay and recombinant immunoblot assay anti-hepatitis C virus （HCV） tests were performed for two groups. Positive serum specimens were retested using polymerase chain reaction （PCR） for HCV RNA. Risk factors were evaluated using a questionnaire. Reported risk factors among infected subjects （＂HCV-positive＂） were compared to those of subjects never exposed （＂HCV-negative＂） to HCV. RESULTS： A total of 514 subjects were studied for HCV, of which 254 were HCV-positive and 260 HCV- negative donors comprised the control group. Mean age of the patients was 28.4 （Std 15.22） years. HCV-positive subjects were more likely to be of male gender （63% versus 37%）. Transfusion 132 （52%）, non-intravenous （n-iv） drug abuse and iv drug abuse 37 （14.5%）, haemodialysis 25 （10%）, receiving wounds at war and extramarital sexual activities （2.4%）, tattooing （3.6%） were found to be independent risk factors of being HCV-positive. No apparent risk factors could be demonstrated in 29 （11.2%） of the positive cases. CONCLUSION： Our data indicate that a history of transfusion and iv drug abuse and haemodialysis are important risk factors for HCV infection in our area and that more careful pretransfusion screening of blood for anti- HCV must be introduced in our blood banks. Improvements in certain lifestyle patterns, and customs in this area may be essential to prevent transmission of the infection.展开更多
There is a direct link between the extent of formation damage and the filtration volume of the drilling fluids in hydrocarbon reservoirs.The filtration volume can be diminished by adding different additives to the dri...There is a direct link between the extent of formation damage and the filtration volume of the drilling fluids in hydrocarbon reservoirs.The filtration volume can be diminished by adding different additives to the drilling fluids.Recently,nanoparticles have been extensively used for enhancing the filtration characteristics of the drilling fluids.However,there is no reliable model for investigating the influence of this class of additives on the performance of drilling fluids.Hence in this study,two powerful tools ELM(extreme learning machine)and PSO-LSSVM(particle swarm optimization-least square support vector machine)are applied to determine the effect of various nanoparticles on the filtration volume.The assessment of the models is carried out by computing the statistical parameters,and it is found that ELM has a greater ability to predict the filtration volumes,while PSO-LSSVM performs satisfactorily too.The model predictions and experimental results are in excellent agreement as suggested by the values of root mean squared error(RMSE=0.2459),coefficient of determination(R^(2)=0.999),and mean relative error(MRE=2.028%)for the dataset.The statistical analysis shows that the suggested model can predict the filtration volume with great accuracy.Moreover,through sensitivity analysis of the input parameters,it is found that for a specified nanoparticle,the filtration volume is highly influenced by nanoparticle concentration and it is the essential variable for the optimization process.展开更多
AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-hous...AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-household contacts of 60 index cases (40 males and 20 females) of HCV infection and 360 pair- matched controls in Ahwaz JundiShapour University Hospitals from August 1, 1998 to September 1, 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion Organization. Serum samples and demographic data and a medical history including the existence of risk factors for HCV (after a questionnaire on the risk factors for parenteral exposure) were obtained from each subject. Antibodies to HCV were detected employing a commercially available second-generation enzyme immunoassay (EIA, Abbott Ⅱ). Positive serum specimens were retested using a second-generation recombinant immunoblot assay (RIBA-2) and a polymerase chain reaction for HCV RNA. Data analysis was carried out for intra-household clustering. RESULTS: Only 4 of 300 (1.33%) cases of household contacts without percutaneous risk factors were positive for HCV Ab while the remaining 296 family contacts were negative for anti-HCV. The mean age of the index cases was 28.4 (Std 15.22) years. The anti-HCV prevalences in parents, spouses, children of the index cases were 0.87% (1/115), 3.39% (2/59)) and 0.79% (1/126), respectively. Among couple partners negative for anti-HCV antibodies, the mean duration of the sexual relationship was 6 years.The two-couple partners positive for anti-HCV antibodies married the index cases for longer than 15 years. The prevalence of positive HCV Ab among household contacts (1.33%) was not significantly higher than that in the controls (1%) (P > 0.06). CONCLUSION: Intrafamilial transmission of HCV is not the significant transmission route and sexual transmission does not seem to play a role in the intrafamilial spread of HCV infection. Intrafamilial transmission of HCV is possible but occurs at a low rate.展开更多
Fault diagnostics is an important research area including different techniques.Principal component analysis(PCA)is a linear technique which has been widely used.For nonlinear processes,however,the nonlinear principal ...Fault diagnostics is an important research area including different techniques.Principal component analysis(PCA)is a linear technique which has been widely used.For nonlinear processes,however,the nonlinear principal component analysis(NLPCA)should be applied.In this work,NLPCA based on auto-associative neural network(AANN)was applied to model a chemical process using historical data.First,the residuals generated by the AANN were used for fault detection and then a reconstruction based approach called enhanced AANN(E-AANN)was presented to isolate and reconstruct the faulty sensor simultaneously.The proposed method was implemented on a continuous stirred tank heater(CSTH)and used to detect and isolate two types of faults(drift and offset)for a sensor.The results show that the proposed method can detect,isolate and reconstruct the occurred fault properly.展开更多
文摘This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditional methods like blow-down and co-production have limitations, including sand production, water coning, and inefficiency in strong aquifers. To overcome these issues, this research explores CO2 injection near the edge aquifer, aiming to reduce water influx and enhance gas recovery through the propagation of a CO2 plume in the gas-water contact zone. Both synthetic and real compositional reservoir models were studied, with CO2 injection performed while maintaining reservoir pressure below 90% of the initial level. Results show that CO2 sequestration significantly improved recovery, particularly in higher permeability reservoirs, where it reduced aquifer influx and increased gas production by 26% under challenging conditions. While CO2 dissolution in water decreased aquifer influx by 39%, its adverse effect on sweep efficiency led to a reduction in gas and water production by 4.2% and 10%, respectively. The method's effectiveness was not significantly impacted by aquifer permeability, but it was sensitive to vertical-to-horizontal permeability ratios. When applied to a real gas reservoir, the proposed method increased gas production by 14% compared to conventional techniques, with minimal CO2 production over a 112-year period. This study demonstrates the potential of CO2 sequestration as a comprehensive solution for enhancing gas recovery, reducing water production, and mitigating environmental impacts in water-drive gas reservoirs.
基金Supported by Research and Technology Development of Ahvaz Jundishapur University Medical Sciences in collaboration on this project with No.87S.56
文摘Objective:To determine brucellosis's epidemiologic,laboratory,diagnostic and public health features considering brucellosis is endemic in Azna County,western Iran.Methods:This descriptive cross-sectional study was investigated on 43 patients with brucellosis in Azna County. The subjects were the patients with symptoms correspondent with brucellosis and positive Wright and 2ME tests. A questionnaire about demographic,epidemiological and laboratory findings was filled in. Afterwards,patients were treated using usual antimicrobial drugs regimen. The collected data were analyzed by SPSS software version 16.Results:Forty-three subjects were found to be positive in laboratory tests. Incidence of Brucellosis was 59.31 per hundred thousand population. About 34.9% of patients were female and 65.1%male. Nearly 95.2% of human cases were living in rural and 4.8%in urban areas. Around 20.9%of patients had history of animal contact. The commonest transmission was unpasteurized dairy products(79.1%). The most contagious seasons were summer and spring(60.3%). The most common age group was 15-24(27.9%),and about 60.5%of the patients were between 15-44 years old. Disease was more common among housewives(30.2%) and farmers(20.9%). The majority of the patients had Wright test titre=1:320(54.1%) and 2ME test titre=1:160(56.1%) in serological titration.Doxycycline with Rifampin was used for treatment of the greatest of patients(60.4%).Conclusions:In order to control this zoonotic disease,close cooperation of health and veterinary organizations is necessary.
基金Supported by the Iranian Nano Technology Initiative Council and Petroleum University of Technology
文摘In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, inductively coupled plasma atomic emission spectrometer （ICP-AES）, temperature programmed reduction （H2-TPR）, CO chemisorption, energy dispersive X-ray （EDX） and scanning electron microscopy （SEM） techniques. Kinetic properties of all catalysts were investigated in a batch re- actor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/AlzO3 catalyst enhances its activity as compared to Fe/AlaO3. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/AlzO3 catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fez（MoO4）3 phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fez（MoO4）3 phase has low reducibility, therefore the Fe2（MoO4）3 phase significantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al2O3 catalyst. Overall, this study introduces Fe-Mo/Al2O3 as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.
基金Supported by Research Center of Gastric and Liver Disease in Tehran Taleghani hospital
文摘AIM: To study the loss of heterozygosity (LOH) at 8p21-23 locus in diffuse gastric cancer.METHODS: To evaluate the involvement of this region in gastric cancer, we used eight microsatellite markers covering two Mb of mentioned region, to perform a high-resolution analysis of allele loss in 42 cases of late diffuse gastric adenocarcinoma.RESULTS: Six of these STS makers: D8S1149, D8S1645, D8S1643, D8S1508, D8S1591, and D8S1145 showed 36%, 28%, 37%, 41%, 44% and 53% LOH, respectively.CONCLUSION: A critical region of loss, close to the NAT2 locus and relatively far from FEZ1 gene currently postulated as tumor suppressor gene in this region.
文摘Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.
文摘【目的】蛀茎夜蛾Sesamia spp.是伊朗和其他国家(包括印度、巴基斯坦、斯里兰卡和日本)甘蔗上最具破坏性的害虫。蛀茎夜蛾幼虫钻蛀茎秆,对茎秆产生为害,降低重量和含糖量并降低甘蔗汁品质。应用抗性品种是一种有效的工具,对环境无不利影响。本研究旨在评价甘蔗商业品种对蛀茎夜蛾的抗性。【方法】在伊朗Ahwaz的Salman-Farsi Agro-industry Farms于2013-2014和2014-2015两个连续年份,采用随机区组设计进行5次重复试验。应用了CP69-1062,CP48-103,CP57-614,CP73-21,SP70-1143,IRC99-01,IRC99-02和L62-96 8个品种。在收获前,随机取20株完整的甘蔗茎秆进行蛀茎夜蛾的为害评估。记录受害茎秆百分比、被钻蛀的节间百分比(percent of internodes bored,IB)、出口孔的数目、活的蛀茎夜蛾的数目、每品种每公顷面积中蛾的繁殖量(moth production per hectare of each variety,MP)。【结果】各测定参数在品种间均存在显著差异。从被钻蛀的节间百分比和蛾的繁殖指数判断,L62-96是最敏感的品种(2014年:14.58%IB,95 200 MP/ha;2015年:16.76%IB和111 300 MP/ha),其次是CP69-1062和CP48-103;CP57-614是这两年中抗性最强的品种(2014年:1.24%IB,8 400 MP/ha;2015年:1.02%IB,7 000 MP/ha)。【结论】建议限制敏感品种的栽培,并应用其他控制措施,结合品种抗性,以治理敏感品种中的蛀茎夜蛾。
基金supported by Research Institute of Petroleum Industry-Kermanshah Campus
文摘Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engineering calculations.The experimental measurements,Equations of State （EoS） and empirical correlations are the most common sources of z-Factor calculations.There are more than twenty correlations available with two variables for calculating the z-Factor from fitting in an EoS or just through fitting techniques.However,these correlations are too complex,which require initial value and more complicated and longer computations or have magnitude error.The purpose of this study is to develop a new accurate correlation to rapidly estimate z-Factor.Result of this correlation is compared with large scale of database and experimental data also.Proposed correlation has 1.660 of Absolute Percent Relative Error （EABS） versus Standing and Katz chart and has also 3.221 of EABS versus experimental data.The output of this correlation can be directly assumed or be used as an initial value of other implicit correlations.This correlation is valid for gas coefficient of isothermal compressibility （cg） calculations also.
文摘Determining the rate of asphaltene particle growth is one of the main problems in modeling of asphaltene precipitation and deposition.In this paper,the kinetics of asphaltene aggregation under different precipitant concentrations have been studied.The image processing method was performed on the digital photographs that were taken by a microscope as a function of time to determine the asphaltene aggregation growth mechanisms.The results of image processing by MATLAB software revealed that the growth of asphaltene aggregates is strongly a function of time.Different regions could be recognized during asphaltene particle growth including reaction-and diffusion-limited aggregation followed by reaching the maximum asphaltene aggregate size and start of asphaltene settling and the final equilibrium.Modeling has been carried out to predict the growth of asphaltene particle size based on the fractal theory.General equations have been developed for kinetics of asphaltene aggregation for reaction-limited aggregation and diffusion-limited aggregation.The maximum size of asphaltene aggregates and settling time were modeled by using force balance,acting on asphaltene particles.Results of modeling show a good agreement between laboratory measurements and model calculations.
文摘ObjectiveTo evaluate the antibacterial effect and physicochemical properties of essential oil of Zataria multiflora Boiss.MethodsAntibacterial activity of essential oil of Zataria multiflora Boiss was assessed by agar disc diffusion and minimal inhibitory concentration(MIC) was tested by E test.ResultsThe essential oil of Zataria multiflora Boiss was effective on pathogenic bacteria particularly Staphylococcus aureus (S. aureus). The MIC values of the target cultures ranged from 0.39 mg/mL to 1.56 mg/mL. The physicochemical properties like effects of pH, temperature, detergents, and enzymes on the activity of essential oil from Zataria multiflora Boiss were also determined. The essential oil was quite stable to temperature as tested against S. aureus and Escherichia coli (E. coli). The essential oil was very stable over a wide range of pH. The antibacterial activity of essential oil was insensitive to various protein-denaturing detergents (Such as Tween 80, Tween 20, Triton 100, etc.) and enzymes (namely proteinase K, trypsin, lipase, and lysosyme).ConclusionsA potential use of the essential oil from Zataria multiflora Boiss is suggested. More studies including further purification, mass spectra, nuclear magnetic resonance (NMR) and evaluation of toxicity are needed for confirmation of this suggestion.
文摘An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that a-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.
文摘Nanofluids and low-salinity water(LSW)flooding are two novel techniques for enhanced oil recovery.Despite some efforts on investigating benefits of each method,the pros and cons of their combined application need to be evaluated.This work sheds light on performance of LSW augmented with nanoparticles through examining wettability alteration and the amount of incremental oil recovery during the displacement process.To this end,nanofluids were prepared by dispersing silica nanoparticles(0.1 wt%,0.25 wt%,0.5 wt% and 0.75 wt%)in 2,10,20 and 100 times diluted samples of Persian Gulf seawater.Contact angle measurements revealed a crucial role of temperature,where no wettability alteration occurred up to 80 ℃.Also,an optimum wettability state(with contact angle 22°)was detected with a 20 times diluted sample of seawater augmented with 0.25 wt% silica nanoparticles.Also,extreme dilution(herein 100 times)will be of no significance.Throughout micromodel flooding,it was found that in an oil-wet condition,a combination of silica nanoparticles dispersed in 20 times diluted brine had the highest displacement efficiency compared to silica nanofluids prepared with deionized water.Finally,by comparing oil recoveries in both water-and oil-wet micromodels,it was concluded that nanoparticles could enhance applicability of LSW via strengthening wettability alteration toward a favorable state and improving the sweep efficiency.
基金supported by the Research Institute of Petroleum Industry-Kermanshah Campus.
文摘In recent years, there has been an increase of interest in the flow of gases at relatively high pressures and high temperatures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well as through the porous media constituting natural petroleum reservoirs, requires knowledge of the viscosity of the fluid at the pressure and temperature involved. Although there are numerous publications concerning the viscosity of methane at atmospheric pressure, there appears to be little information available relating to the effect of pressure and temperature upon the viscosity. A survey of the literature reveals that the disagreements between published data on the viscosity of methane are common and that most investigations have been conducted over restricted temperature and pressure ranges. Experimental viscosity data for methane are presented for temperatures from 320 to 400 K and pressures from 3000 to 140000 kPa by using falling body viscometer. A summary is given to evaluate the available data for methane, and a comparison is presented for that data common to the experimental range reported in this paper. A new and reliable correlation for methane gas viscosity is presented. Predicted values are given for temperatures up to 400 K and pressures up to 140000 kPa with Average Absolute Percent Relative Error （EABS） of 0.794.
文摘Rock typing is an important tool in evaluation and performance prediction of reservoirs.Different techniques such as flow zone indicator(FZI),FZI~*and Winland methods are used to categorize reservoir rocks into distinct rock types.Generally,these methods are applied to petrophysical data that are measured at a pressure other than reservoir pressure.Since the pressure changes the pore structure of rock,the effect of overburden pressure on rock typing should be considered.In this study,porosity and permeability of 113 core samples were measured at five different pressures.To investigate the effect of pressure on determination of rock types,FZI,FZI~*and Winland methods were applied.Results indicated that although most of the samples remain in the same rock type when pressure changes,some of them show different trends.These are related to the mineralogy and changes in pore system of the samples due to pressure change.Additionally,the number of rock types increases with increasing pressure.Furthermore,the effect of overburden pressure on determination of rock types is more clearly observed in the Winland and FZI~*methods.Also,results revealed that a more precise reservoir dynamic simulation can be obtained by considering the reservoir rock typing process at reservoir conditions.
文摘This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.
文摘Knowing the current condition of the faults and fractures in a reservoir is crucial for production and injection activities.A good estimation of the fault reactivation potential in the current stress field is a useful tool for locating the appropriate spot to drill injection wells and to calculate the maximum sustainable pore pressure in enhanced oil recovery and geosequestration projects.In this study,after specifying the current stress state in the Gachsaran oilfield based on Anderson’s faulting theory,the reactivation tendency of four faults(F1,F2,F3,and F4)in the Asmari reservoir is analyzed using 3D Mohr diagrams and slip tendency factors.Results showed that all the faults are stable in the current stress state,and F2 has the potential to undergo the highest pore pressure build-up in the field.On the other hand,F3 has the proper conditions(i.e.,strike and dip referring to σHmax orientation)for reactivation.Stress polygons were also applied to show the effect of the pore pressure increase on fault stability,in a graphical manner.According to the results,the best location for drilling a new injection well in this part of the field is the NW side of F2,due to the lower risk of reactivation.It was found that both methods of 3D Mohr diagrams and slip tendency factors predict similar results,and with the lack of image logs for stress orientation determination,the slip tendency method can be applied.The results of such studies can also be used for locating safe injection points and determining the injection pressure prior to numerical modeling in further geomechanical studies.
文摘AIM：To evaluate possible risk factors for the spread of hepatitis C infection and to analyze the characteristics of the epidemiological and clinical patterns among the patients with hepatitis C infection. METHODS： During a five-year period a cross-sectional study was conducted among HCV positive individuals referred to the Ahwaz JundiShapour University Hospitals （AJSUH） and Hepatitis Clinic from 1 Sept 1999 to 1 Sept 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion organization. Enzyme-linked immunosorbent assay and recombinant immunoblot assay anti-hepatitis C virus （HCV） tests were performed for two groups. Positive serum specimens were retested using polymerase chain reaction （PCR） for HCV RNA. Risk factors were evaluated using a questionnaire. Reported risk factors among infected subjects （＂HCV-positive＂） were compared to those of subjects never exposed （＂HCV-negative＂） to HCV. RESULTS： A total of 514 subjects were studied for HCV, of which 254 were HCV-positive and 260 HCV- negative donors comprised the control group. Mean age of the patients was 28.4 （Std 15.22） years. HCV-positive subjects were more likely to be of male gender （63% versus 37%）. Transfusion 132 （52%）, non-intravenous （n-iv） drug abuse and iv drug abuse 37 （14.5%）, haemodialysis 25 （10%）, receiving wounds at war and extramarital sexual activities （2.4%）, tattooing （3.6%） were found to be independent risk factors of being HCV-positive. No apparent risk factors could be demonstrated in 29 （11.2%） of the positive cases. CONCLUSION： Our data indicate that a history of transfusion and iv drug abuse and haemodialysis are important risk factors for HCV infection in our area and that more careful pretransfusion screening of blood for anti- HCV must be introduced in our blood banks. Improvements in certain lifestyle patterns, and customs in this area may be essential to prevent transmission of the infection.
文摘There is a direct link between the extent of formation damage and the filtration volume of the drilling fluids in hydrocarbon reservoirs.The filtration volume can be diminished by adding different additives to the drilling fluids.Recently,nanoparticles have been extensively used for enhancing the filtration characteristics of the drilling fluids.However,there is no reliable model for investigating the influence of this class of additives on the performance of drilling fluids.Hence in this study,two powerful tools ELM(extreme learning machine)and PSO-LSSVM(particle swarm optimization-least square support vector machine)are applied to determine the effect of various nanoparticles on the filtration volume.The assessment of the models is carried out by computing the statistical parameters,and it is found that ELM has a greater ability to predict the filtration volumes,while PSO-LSSVM performs satisfactorily too.The model predictions and experimental results are in excellent agreement as suggested by the values of root mean squared error(RMSE=0.2459),coefficient of determination(R^(2)=0.999),and mean relative error(MRE=2.028%)for the dataset.The statistical analysis shows that the suggested model can predict the filtration volume with great accuracy.Moreover,through sensitivity analysis of the input parameters,it is found that for a specified nanoparticle,the filtration volume is highly influenced by nanoparticle concentration and it is the essential variable for the optimization process.
文摘AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-household contacts of 60 index cases (40 males and 20 females) of HCV infection and 360 pair- matched controls in Ahwaz JundiShapour University Hospitals from August 1, 1998 to September 1, 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion Organization. Serum samples and demographic data and a medical history including the existence of risk factors for HCV (after a questionnaire on the risk factors for parenteral exposure) were obtained from each subject. Antibodies to HCV were detected employing a commercially available second-generation enzyme immunoassay (EIA, Abbott Ⅱ). Positive serum specimens were retested using a second-generation recombinant immunoblot assay (RIBA-2) and a polymerase chain reaction for HCV RNA. Data analysis was carried out for intra-household clustering. RESULTS: Only 4 of 300 (1.33%) cases of household contacts without percutaneous risk factors were positive for HCV Ab while the remaining 296 family contacts were negative for anti-HCV. The mean age of the index cases was 28.4 (Std 15.22) years. The anti-HCV prevalences in parents, spouses, children of the index cases were 0.87% (1/115), 3.39% (2/59)) and 0.79% (1/126), respectively. Among couple partners negative for anti-HCV antibodies, the mean duration of the sexual relationship was 6 years.The two-couple partners positive for anti-HCV antibodies married the index cases for longer than 15 years. The prevalence of positive HCV Ab among household contacts (1.33%) was not significantly higher than that in the controls (1%) (P > 0.06). CONCLUSION: Intrafamilial transmission of HCV is not the significant transmission route and sexual transmission does not seem to play a role in the intrafamilial spread of HCV infection. Intrafamilial transmission of HCV is possible but occurs at a low rate.
基金Project(1390/2)supported by Khuzestan Gas Company,Iran
文摘Fault diagnostics is an important research area including different techniques.Principal component analysis(PCA)is a linear technique which has been widely used.For nonlinear processes,however,the nonlinear principal component analysis(NLPCA)should be applied.In this work,NLPCA based on auto-associative neural network(AANN)was applied to model a chemical process using historical data.First,the residuals generated by the AANN were used for fault detection and then a reconstruction based approach called enhanced AANN(E-AANN)was presented to isolate and reconstruct the faulty sensor simultaneously.The proposed method was implemented on a continuous stirred tank heater(CSTH)and used to detect and isolate two types of faults(drift and offset)for a sensor.The results show that the proposed method can detect,isolate and reconstruct the occurred fault properly.
