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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Gas Processing Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: modeling,System identification,Debutanizer Column,Dynamic Neural Networks
- چکیده:
- چکیده انگلیسی: Â Abstract: In this paper, Artificial Neural Network (ANN) was used for modeling the nonlinear structure of a debutanizer column in a refinery gas process plant. The actual input-output data of the system were measured in order to be used for system identification based on root mean square error (RMSE) minimization approach. It was shown that the designed recurrent neural network is able to precisely predict and track the response of the actual system. The comparison between the results of this paper and those of the most recent published studies as NARX model indicates the significance of the proposed approach.
- انتشار مقاله: 26-03-1395
- نویسندگان: Majid Amidpour,Gholam Reza Salehi,Ali Ghaffari,Hamed Sahraei
- مشاهده
- جایگاه : پژوهشی
- مجله: Gas Processing Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Simulated Annealing,Exergy analysis,Irreversibility Index,process simulation,Process Optimization
- چکیده:
- چکیده انگلیسی: Abstract: In this paper, an exergy analysis approach is proposed for optimal design of distillation column by using simulated annealing algorithm. First, the simulation of a distillation column was performed by using the shortcut results and irreversibility in each tray was obtained. The area beneath the exergy loss profile was used as Irreversibility Index in the whole column. Then, First Optimization Algorithm (simulated annealing, SA) was implemented to Grassroots (Number of tray (N) vs. Reflux Ratio (RR)) and Retrofit (Nof vs. Feed splitting) cases, respectively. Next, SA was used to find the maximum recovery in a simple column by seven different variables (Feed Temperature, Feed Pressure, Reflux Rate, Number of theoretical stage, Feed Trays (Feed Splitting, three variables)) simultaneously. During the search for maximum recovery, it was tried to find a better Irreversibility Index. In the second part, SA optimization algorithm was used for a complex column with one pump-around and feed splitter to find a better condition, which means to find the best location for pump-around and feed trays in Distillation column. The main objective in SA was to maximize the recovery of the desired component and to find a better minimum Irreversibility Index. This method was implemented in de-ethanizer in the first optimization without using pump-around with seven degrees of freedom, Recovery growth was 5.1% and reduction in irreversibility index was 3%. At the best Irreversibility Index, growth of recovery was about 3.7% and irreversibility index reduction was 25%. In the second optimization with pump-around or eight different variables, in the best condition, Recovery Growth was 6.2% but had a very high Irreversibility Index. At the best irreversibility index, recovery reduction was 17% but reduction in irreversibility index was about 21% comparing with initial point. As a result, it is shown that, regarding recovery and Irreversibility, pump-around shouldnât be used in a column. Without using pump-around, a better condition, considering both factors, can be achieved.
- انتشار مقاله: 26-03-1395
- نویسندگان: Gholam Reza Salehi,Majid Amidpour,Amir Salehi,Mostafa Maleki,Bahram Ghorbani
- مشاهده
- جایگاه : پژوهشی
- مجله: Gas Processing Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Mixed Refrigerant Cycle,Low Temperature Process,Optimal Operating Conditions
- چکیده:
- چکیده انگلیسی: Abstract: Minimizing the work consumed in refrigeration system is the most effective measure to reduce the cost of products in sub-ambient chemical processes. The introduction of mixed working fluids into refrigeration system in place of pure working fluids is a recent advancement applied in the field. Due to the lack of systematic design method for Mixed Refrigerant Cycle (MRC), conventional approaches are largely trial-and-error, and therefore, operations might be far away from Optimal operating conditions. In this paper, a novel method for systematic design of MRCs with a given configuration is presented. It combines the benefits of thermodynamics approach and mathematical optimization. An ethylene process was chosen as a typical example of low temperature process. The simulation results show that MRCs can improve the thermodynamic performance of refrigeration system in the case of using Optimal operating conditions and also proper arrangement of the cycle components (cycle configuration).
- انتشار مقاله: 26-03-1395
- نویسندگان: Mostafa Mafi,Majid Amidpour,Mojtaba Nayenian,Gholam Reza Salehi,Bahram Ghorbani
- مشاهده
- جایگاه : پژوهشی
- مجله: Gas Processing Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Simulation,Flare Gas,Expansion Turbine,economy,Environmental Flow Diagram
- چکیده:
- چکیده انگلیسی: Regarding the increased energy consumption of the processes at the operational units in the National Iranian Oil Company, the present study analyzed energy consumption at one of the gas refineries. In this refinery, which is the main supplier of Fajr Jam refinery for the national gas network, as well as an injection into the oil fields of the Iranian South oil company, the pressure of gas after passing through a Joule Thomson valvefrom120 to 70 barg reduced. This pressure drop results in the loss of gas temperature, as a result, temperature decrease to -15 °c. Due to the sudden drop in gas pressure, considerable energy, it will be lost. Replacing the Joule Thomson valve with an expansion turbine to use its recoverable energy was also studied. Based on the results from HYSYS software as well as the refinery’s operational conditions, three solutions were discussed. These solutions include (1) using an expansion turbine for power generation, (2) using an expansion turbine to generate electricity and gas condensates, and (3) using an expansion turbine to produce condensates. Based on the technical and economic analysis of the solutions, as well as the results from environmental flow diagram (EFD), which is designed to compare the rates and the sources of the environmental pollutants, the second solution with an internal rate of return (IRR) of 74.53% and a payback period (PBP) of 1.3 years is regarded as the most suitable scenario. Results from EFD indicate that using the second scenario will decrease CO, CO2, and NOX by 57% in this refinery.
- انتشار مقاله: 22-12-1398
- نویسندگان: Seyed Morteza Mousavi,Kamran Lari,Gholamreza Salehi,Masoud Torabi Azad
- مشاهده
- جایگاه : پژوهشی
- مجله: Current Medical Mycology
- نوع مقاله: Journal Article
- کلمات کلیدی: Candidiasis,Aspergillosis,Mucormycosis,Invasive fungal infections,organ transplantation
- چکیده:
- چکیده انگلیسی: Background and Purpose: Organ transplant recipients are vulnerable to fungal infections. The aim of this study was to determine the prevalence of fungal colonization and infections among patients who underwent various transplantations and molecularly characterize the etiological agents.
Materials and Methods: This study was conducted on candidates for transplantation in Imam Khomeini Hospital, Tehran, Iran, from April 2017 to April 2018. All patients were monitored for fungal colonization or infections before and after transplantation. Isolated fungi were identified using molecular methods.
Results: A total of 125 patients, including 86 males and 39 females, with the mean age of 52.2 years participated in the study (age range: 15-75 years). Out of 125 patients, 84 (67.2%) cases had fungal colonization that appeared pre- and post-transplantation in 21 and 63 cases, respectively (alone or concurrent with another infection in 55 and 29 cases, respectively). In addition, a total of 39 episodes of fungal infections were diagnosed in 36 (28.8%) recipients (alone or concurrent with colonization in 7 and 29 cases, respectively). Out of the 39 fungal infections, 9 cases appeared pre-transplantation, while the other 30 cases occurred post-transplantation. However, no fungal colonization or infection was observed in 34 (27.2%) patients. Oral candidiasis (n=20) was the most common type of infection, followed by funguria (n=7), onychomycosis (n=5), candidemia (n=3), rhinocerebral mucormycosis (n=1), cutaneous mucormycosis (n=1), cutaneous aspergillosis (n=1), and peritonitis (n=1). Six yeast species were recovered from colonization cases with the dominance of Candida albicans both before and after transplantation. The observed fungal infections were caused by 11 distinct species, including the members of Candida (i.e., C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei), Aspergillus (i.e., A. oryzae and A. candidus), Rhizopus (i.e., R. oryzae and R. microsporus), Trichosporon asahii, and Trichophyton interdigitale. The results also indicated that the development of a fungal infection post-transplantation was associated with fungal colonization (r=0.0184; P=0.043).
Conclusion: Based on the results, fungal colonization was a common finding in transplant recipients at Imam Khomeini Hospital. However, the incidence of fungal infections was comparable with those of other centers. As the oral cavity was the most common site of colonization and infection, it might be beneficial to take further care about the oral health of patients using effective mouthwash.- انتشار مقاله: 15-07-1398
- نویسندگان: Fereshteh Zarei,Jamal Hashemi,Mohamadreza Salehi,Shahram Mahmoudi,Ensieh Zibafar,Zahra Ahmadinejad,Abbas Rahimi Foroushani,Pegah Ardi,Roshanak Daie Ghazvini
- مشاهده
- جایگاه : پژوهشی
- مجله: Avicenna Journal of Phytomedicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Traditional Persian Medicine,Pemphigus vulgaris,Cassia fistula L,Topical therapy
- چکیده:
- چکیده انگلیسی: Objective: Cassia fistula L. fruit extract has been traditionally used in the treatment of pemphigus vulgaris (PV) lesions in Iran. The aim of this study was to determine the efficacy of C. fistula fruit gel on healing time of PV lesions in a clinical setting.
Materials and Methods: This was a randomized, double-blind placebo-controlled clinical trial that was performed in dermatology ward at Saadi hospital, affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. Right- or left- sided lesions of PV patients on standard systemic treatment were randomized for treatment with either C. fistula fruit gel or placebo prescribed twice daily. The largest diameter of each lesion was measured at the baseline (day 0) and on days 10 and 20. Epithelialization Index (EI), as outcome measure was calculated and compared between the two groups.
Results: The present study comprised 20 patients, with overall 82 cutaneous lesions including 41 lesions in the C. fistula fruit gel group and 41 lesions in the placebo group. The EI in the C. fistula fruit gel group was significantly higher than that of the placebo group both on day 10 (65±28vs 30±34; p=0.001) and at the end of the study (91±22 vs 69±49; p=0.003).
Conclusion: Topical application of C. fistula fruit gel can be considered as an effective adjuvant therapy in treatment of PV.- انتشار مقاله: 14-09-1396
- نویسندگان: Fatemh Atarzadeh,Mohammad Kamalinejad,Gholam Reza Amin,Ali Reza Salehi,Ladan Dastgheib,Amir Mohammad Jaladat,Mojtaba Heydari,Zahra Gouyandeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Avicenna Journal of Phytomedicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Traditional Persian Medicine,Pemphigus vulgaris,Cassia fistula L,Topical therapy
- چکیده:
- چکیده انگلیسی: Objective: Cassia fistula L. fruit extract has been traditionally used in the treatment of pemphigus vulgaris (PV) lesions in Iran. The aim of this study was to determine the efficacy of C. fistula fruit gel on healing time of PV lesions in a clinical setting.
Materials and Methods: This was a randomized, double-blind placebo-controlled clinical trial that was performed in dermatology ward at Saadi hospital, affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. Right- or left- sided lesions of PV patients on standard systemic treatment were randomized for treatment with either C. fistula fruit gel or placebo prescribed twice daily. The largest diameter of each lesion was measured at the baseline (day 0) and on days 10 and 20. Epithelialization Index (EI), as outcome measure was calculated and compared between the two groups.
Results: The present study comprised 20 patients, with overall 82 cutaneous lesions including 41 lesions in the C. fistula fruit gel group and 41 lesions in the placebo group. The EI in the C. fistula fruit gel group was significantly higher than that of the placebo group both on day 10 (65±28vs 30±34; p=0.001) and at the end of the study (91±22 vs 69±49; p=0.003).
Conclusion: Topical application of C. fistula fruit gel can be considered as an effective adjuvant therapy in treatment of PV.- انتشار مقاله: 14-09-1396
- نویسندگان: Fatemh Atarzadeh,Mohammad Kamalinejad,Gholam Reza Amin,Ali Reza Salehi,Ladan Dastgheib,Amir Mohammad Jaladat,Mojtaba Heydari,Zahra Gouyandeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Avicenna Journal of Phytomedicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Nigella sativa,Bleomycin,Hydroxyproline,Pulmonary inflammation Fibrosis
- چکیده:
- چکیده انگلیسی: Objective: Pulmonary fibhrosis is a disease of the connective tissues in the respiratory system. Nigella sativa has been used for the treatment of pulmonary diseases like asthma. This study investigated the early and late preventive effect of methanolic extract of N. sativa on a bleomycin- induced pulmonary fibrosis model.
Materials and Methods: This study was carried out using 52 rats. Pulmonary fibrosis was induced by a single endotracheal injection of bleomycin (5 mg/kg). Extract of N. sativa (500 mg/kg per day) or methylprednisolone succinate (4 mg/kg per day) was injected intraperitoneally in two periods (i.e. days 1-14 as early preventive group and days 15-28 days as late preventive group). The lung tissues were histologically examined at the end of each period and inspected for the amount of hydroxyproline and biomarkers of oxidative stress.
Results: The pulmonary inflammation and fibrosis were significantly decreased in groups treated with methylprednisolone and N. sativa extract compared to bleomycin group in both early and late prevention groups (p<0.001). The hydroxyproline concentration in pulmonary tissue was significantly decreased in N. sativa and methylprednisolone groups compared to the bleomycin group in both prevention groups (p<0.001). Significant reductions in lipid peroxidation (p<0.001) and increases in catalase activity were also observed in N. sativa and methylprednisolone groups compared to bleomycin group.
Conclusion: This study suggested that N. Sativa extract is effective for early and late prevention of pulmonary fibrosis and inflammation. However, more studies are needed to identify its anti-inflammatory and anti-fibrotic mechanisms in the respiratory system.- انتشار مقاله: 27-06-1396
- نویسندگان: Hamid Reza Poursalehi,Mitra Samareh Fekri,Fariba Sharififar,Ali Mandegary,Atefeh Izadi,Rahil Mahmoodi,Mohammad Hadi Nematollahi,Fateme Porgholamhosein,Vahideh Ghorani,Masome Samareh Fekri
- مشاهده
- جایگاه : پژوهشی
- مجله: Biofuel Research Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Genetic Engineering,Biodiesel,Nonedible oil plants,Oil content,Oil composition,Biotic and abiotic stress tolerance
- چکیده:
- چکیده انگلیسی: Biodiesel has huge potentials as a green and technologically feasible alternative to fossil diesel. However, biodiesel production from edible oil crops has been widely criticized while nonedible oil plants are associated with some serious disadvantages, such as high cost, low oil yield, and unsuitable oil composition. The next generation sequencing (NGS), omics technologies, and genetic engineering have opened new paths toward achieving high performance-oil plants varieties for commercial biodiesel production. The intent of the present review paper is to review and critically discuss the recent genetic and metabolic engineering strategies developed to overcome the shortcoming faced in nonedible plants, including Jatropha curcas and Camelina sativa, as emerging platforms for biodiesel production. These strategies have been looked into three different categories. Through the first strategy aimed at enhancing oil content, the key genes involved in triacylglycerols (TAGs) biosynthesis pathway (e.g., diacylglycerol acyltransferase (DGAT), acetyl-CoA carboxylase (ACCase), and glycerol‐3‐phosphate dehydrogenase (GPD1)), genes affecting seed size and plant growth (e.g., transcription factors (WRI1), auxin response factor 19 (ARF19), leafy cotyledon1 (LEC1), purple acid phosphatase 2 (PAP2), G-protein c subunit 3 (AGG3), and flowering locus T (FT)), as well as genes involved in TAGs degradation (e.g., sugar-dependent protein 1 triacylglycerol lipase (SDP1)) have been deliberated. While through the second strategy targeting enhanced oil composition, suppression of the genes involved in the biosynthesis of linoleic acids (e.g., fatty acid desaturase (FAD2), fatty acid elongase (FAE1), acyl-ACP thioesterase (FATB), and ketoacyl-ACP synthase II (KASII)), suppression of the genes encoding toxic metabolites (curcin precursor and casbene synthase (JcCASA)), and finally, engineering the genes responsible for the production of unusual TAGs (e.g., Acetyl-TAGs and hydroxylated fatty acids (HFA)) have been debated. In addition to those, enhancing tolerance to biotic (pest and disease) and abiotic (drought, salinity, freezing, and heavy metals) stresses as another important genetic engineering strategy to facilitate the cultivation of nonedible oil plants under conditions unsuitable for food crops has been addressed. Finally, the challenges faced prior to successful commercialization of the resultant GM oil plants such have been presented.
- انتشار مقاله: 13-03-1397
- نویسندگان: Gholamreza Salehi Jouzani,Reza Sharafi,Saeed Soheilivand
- مشاهده
- جایگاه : پژوهشی
- مجله: Biofuel Research Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Lignocellulosic biomass,Bioethanol,Biobutanol,Bioalcohols,Consolidated bioprocessing,Starchy biomass
- چکیده:
- چکیده انگلیسی: Recently, lignocellulosic biomass as the most abundant renewable resource has been widely considered for bioalcohols production. However, the complex structure of lignocelluloses requires a multi-step process which is costly and time consuming. Although, several bioprocessing approaches have been developed for pretreatment, saccharification and fermentation, bioalcohols production from lignocelluloses is still limited because of the economic infeasibility of these technologies. This cost constraint could be overcome by designing and constructing robust cellulolytic and bioalcohols producing microbes and by using them in a consolidated bioprocessing (CBP) system. This paper comprehensively reviews potentials, recent advances and challenges faced in CBP systems for efficient bioalcohols (ethanol and butanol) production from lignocellulosic and starchy biomass. The CBP strategies include using native single strains with cellulytic and alcohol production activities, microbial co-cultures containing both cellulytic and ethanologenic microorganisms, and genetic engineering of cellulytic microorganisms to be alcohol-producing or alcohol producing microorganisms to be cellulytic. Moreover, high-throughput techniques, such as metagenomics, metatranscriptomics, next generation sequencing and synthetic biology developed to explore novel microorganisms and powerful enzymes with high activity, thermostability and pH stability are also discussed. Currently, the CBP technology is in its infant stage, and ideal microorganisms and/or conditions at industrial scale are yet to be introduced. So, it is essential to bring into attention all barriers faced and take advantage of all the experiences gained to achieve a high-yield and low-cost CBP process.
- انتشار مقاله: 30-07-1393
- نویسندگان: Gholamreza Salehi Jouzani,Mohammad J. Taherzadeh
- مشاهده