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| 1 | Diagnostic dilemma of abdominal tuberculosis in non-HIV patients:An ongoing challenge for physicians显示文摘AIM: To assess the clinical features, yield of the diagnostic tests and outcome of abdominal tuberculosis in non-HIV patients. METHODS: Adult patients with discharge diagnosis of abdominal tuberculosis (based upon; positive microbiology, histo-pathology, imaging or response to trial of anti TB drugs) during the period 1999 to 2004 were analyzed. Patient’s characteristics, laboratory investigations, radiological, endoscopic and surgical findings were evaluated. Abdominal site involved (intestinal, peritoneal, visceral, and nodal) and response to treatment was also noted. RESULTS: There were 209 patients enrolled. One hundred and twenty-three (59%) were females. Symptoms were abdominal pain 194 (93%), fever 134 (64%), night sweats 99 (48%), weight loss 98 (47%), vomiting 75 (36%), ascites 74 (35%), constipation 64 (31%), and diarrhea 25 (12%). Sub-acute and acute intestinal obstruction was seen in 28 (13%) and 12 (11%) respectively. Radiological evidence of pulmonary tuberculosis was found in 134 (64%) patients. Basis of diagnosis of abdominal tuberculosis were radiology (Chest and barium X-Rays, Ultrasound and CT scan abdomen) in 111 (53%) and histo-pathology (tissue obtained during surgery, colonoscopy, CT or ultrasound guided biopsy, laparoscopy and upper gastro intestinal endoscopy) in 87 (42%) patients. Mycobacterium culture was positive in 6/87 (7%) patients and response to therapeutic trial of anti tubercular drugs was the basis of diagnosis in 5 (2.3%) patients. Predominant site of involvement by abdominal TB was intestinal in 103 (49%) patients, peritoneal in 87 (42%) patients, solid viscera in 10 (5%) and nodal in 9 (4%) patients. Response to medical treatment was found in 158 (76%) patients andadditionally 35 (17%) patients also underwent surgery. In a 425 ± 120 d follow-up period 12 patients died (eight post operative) and no case of relapse was noted. CONCLUSION: Abdominal TB has diverse and non- specific symptomatology. No single test is adequate for diagnosis of abdominal tuberculosis in all patients. Abdominal TB in non-HIV patients remains an ongoing diagnostic dilemma requiring a high index of clinical suspicion. | Rustam Khan Shahab Abid Wasim Jafri Zaigham Abbas Khalid Hameed Zubair Ahmad | 2006 | World Journal of Gastroenterology2006,12,39: | 17 |
| 2 | 高锰酸钾改性桉木生物炭对Pb(Ⅱ)的吸附特性显示文摘以桉木为原料,使用高锰酸钾对桉木生物炭(BC)进行改性,制备改性生物炭(KBC).对其进行表征,并进行了水溶液中Pb(Ⅱ)的静态吸附实验,探究了溶液pH、吸附剂投加量、吸附时间、温度和初始浓度对Pb(Ⅱ)的吸附效果影响.结果表明,最佳吸附反应pH为5,吸附在6 h达到饱和,当温度为25℃,Pb(Ⅱ)的初始浓度为100 mg·L^(-1),吸附剂投加量为0.06 g时,KBC对Pb(Ⅱ)的最大吸附量为83.059 mg·g^(-1),去除率为99.67%.KBC对Pb(Ⅱ)的吸附遵循二级动力学模型和Langmuir等温吸附模型,其是发生在均匀表面的单层吸附.采用BET、SEM-EDS、XRD、FT-IR和XPS对吸附剂进行表征分析,发现吸附机制主要是KBC含氧和KBC含锰基团通过络合作用和沉淀作用来吸附Pb(Ⅱ),以及在吸附过程中生物炭表面会形成—O—Pb—O—双齿配合物.因此,高锰酸钾改性BC可以作为一种很好的Pb(Ⅱ)吸附剂. | 莫贞林 曾鸿鹄 林华 Asfandyar Shahab 石清亮 张华 | 2021 | 环境科学2021,42,11: | 17 |
| 3 | Functional gastrointestinal disorders and gut-brain axis: What does the future hold?显示文摘Despite their high prevalence, lack of understanding of the exact pathophysiology of the functional gastrointestinal disorders has restricted us to symptomatic diagnostic tools and therapies. Complex mechanisms underlying the disturbances in the bidirectional communication between the gastrointestinal tract and the brain have a vital role in the pathogenesis and are key to our understanding of the disease phenomenon. Although we have come a long way in our understanding of these complex disorders with the help of studies on animals especially rodents, there need to be more studies in humans, especially to identify the therapeutic targets. This review study looks at the anatomical features of the gut-brain axis in order to discuss the different factors and underlying molecular mechanisms that may have a role in the pathogenesis of functional gastrointestinal disorders. These molecules and their receptors can be targeted in future for further studies and possible therapeutic interventions. The article also discusses the potential role of artificial intelligence and machine learning and its possible role in our understanding of these scientifically challenging disorders. | Kashif Mukhtar Hasham Nawaz Shahab Abid | 2019 | World Journal of Gastroenterology2019,25,5: | 15 |
| 4 | Is it time to replace propranolol with carvedilol for portal hypertension?显示文摘Beta-adrenergic receptor antagonists(β-blockers) have been well established for use in portal hypertension for more than three decades. Different Non-selective β-blockers like propranolol, nadolol, timolol, atenolol, metoprolol and carvedilol have been in clinical practice in patients with cirrhosis. Carvedilol has proven 2-4 times more potent than propranolol as a beta-receptor blocker in trials conducted testing its efficacy for heart failure. Whether the same effect extends to its potency in the reduction of portal venous pressures is a topic of on-going debate. The aim of this review is to compare the hemodynamic and clinical effects of carvedilol with propranolol, and attempt assess whether carvedilol can be used instead of propranolol in patients with cirrhosis. Carvedilol is a promising agent among the beta blockers of recent time that has shown significant effects in portal hypertension hemodynamics. It has also demonstrated an effective profile in its clinical application specifically for the prevention of variceal bleeding. Carvedilol has more potent desired physiological effects when compared to Propranolol. However, it is uncertain at the present juncture whether the improvement in hemodynamics also translates into a decreased rate of disease progression and complications when compared to propranolol. Currently Carvedilol shows promise as a therapy for portal hypertension but more clinical trials need to be carried out before we can consider it as a superior option and a replacement for propranolol. | Shahab Abid Saadat Ali Muhammad Asif Baig Anam Akbar Waheed | 2015 | World Journal of Gastrointestinal Endoscopy2015,7,5: | 13 |
| 5 | DFT Investigations(Geometry Optimization, UV/Vis, FT-IR, NMR, HOMO-LUMO, FMO, MEP, NBO, Excited States) and the Syntheses of New Pyrimidine Dyes显示文摘In the present work, the molecular structures of two new synthesized dyes:(4,6-dimethylpyrimidin-2-ylamino)(5-p-tolylisoxazol-3-yl)methanol(PS-1) and N-(4,6-dimethylpyrimidin-2-yl)-5-phenylisoxazole-3-carboxamide(PS-2), have been investigated using density functional theory(DFT) in dimethylformamide(DMF) for the first time. The electronic spectra of new dyes in a DMF solvent were carried out by time dependent density functional theory(TD-DFT) method. After quantum-chemical calculations two new dyes for the optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. NucleusIndependent Chemical Shifts(NICS) calculations have also been carried out for the title compounds. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV spectra. The HOMO and LUMO molecular orbitals, excitation energies and oscillator strengths for the dyes have also been calculated and presented. | MASOOME Sheikhi SIYAMAK Shahab LIUDMILA Filippovich EVGENIJ Dikusar MEHRNOOSH Khaleghian | 2018 | Chinese Journal of Structural Chemistry2018,37,8: | 12 |
| 6 | Hot deformation behavior of microstructural constituents in a duplex stainless steel during high-temperature straining显示文摘The hot deformation characteristics of 1.4462 duplex stainless steel(DSS)were analyzed by considering strain partitioning between austenite and ferrite constituents.The individual behavior of ferrite and austenite in microstructure was studied in an iso-stress condition.Hot compression tests were performed at temperatures of 800-1100 C and strain rates of 0.001-1 s 1.The flow stress was modeled by a hyperbolic sine constitutive equation,the corresponding constants and apparent activation energies were determined for the studied alloys.The constitutive equation and law of mixture were used to measure the contribution factor of each phase at any given strain.It is found that the contribution factor of ferrite exponentially declines as the Zener-Hollomon parameter(Z)increases.On the contrary,the austenite contribution polynomially increases with the increase of Z.At low Z values below 2.6.×1015(lnZ=35.5),a negative contribution factor is determined for austenite that is attributed to dynamic recrystallization.At high Z values,the contribution factor of austenite is about two orders of magnitude greater than that of ferrite,and therefore,austenite can accommodate more strain.Microstructural characterization via electron back-scattered difraction(EBSD)confirms the mechanical results and shows that austenite recrystallization is possible only at high temperature and low strain rate. | Amir Momeni Shahab Kazemi Ali Bahrani | 2013 | International Journal of Minerals,Metallurgy and Materials2013,20,10: | 11 |
| 7 | 智能代理在油藏建模中的应用显示文摘利用人工智能和机器学习技术,采用人工神经网络开发并验证了用于油藏模拟历史拟合、敏感性分析和不确定性评估的智能代理模型,将其应用于油藏模拟的两个案例中。第1个案例研究了代理模型在油藏模型历史拟合中的应用,输出结果预测了井的产量;第2个案例研究了基于人工神经网络的代理模型在CO2提高采收率油藏快速建模中的应用,目标为预测油藏压力和相饱和度在注入期间以及注入后的分布,预测效果均良好。相比基础数值模拟模型,智能代理模型运行单次模拟只需几秒钟,总节省98.9%的运算时间。智能代理模型在运算速度、消耗时间以及成本等方面都有巨大的优势。此外,智能代理模型与基础油藏模型模拟结果非常接近。 | SHAHKARAMI Alireza MOHAGHEGH Shahab | 2020 | 石油勘探与开发2020,47,2: | 10 |
| 8 | Hepatitis C virus core protein modulates several signaling pathways involved in hepatocellular carcinoma显示文摘Hepatocellular carcinoma(HCC) is the fifth most common cancer, and hepatitis C virus(HCV) infection plays a major role in HCC development. The molecular mechanisms by which HCV infection leads to HCC are varied. HCV core protein is an important risk factor in HCV-associated liver pathogenesis and can modulate several signaling pathways involved in cell cycle regulation, cell growth promotion, cell proliferation, apoptosis, oxidative stress and lipid metabolism. The dysregulation of signaling pathways such as transforming growth factor β(TGF-β), vascular endothelial growth factor(VEGF), Wnt/β-catenin(WNT), cyclooxygenase-2(COX-2) and peroxisome proliferator-activated receptor α(PPARα) by HCV core protein is implicated in the development of HCC. Therefore, it has been suggested that this protein be considered a favorable target for further studies in the development of HCC. In addition, considering the axial role of these signaling pathways in HCC, they are considered druggable targets for cancer therapy. Therefore, using strategies to limit the dysregulation effects of core protein on these signaling pathways seems necessary to prevent HCV-related HCC. | Shahab Mahmoudvand Somayeh Shokri Reza Taherkhani Fatemeh Farshadpour | 2019 | World Journal of Gastroenterology2019,25,1: | 8 |
| 9 | Predictive factors for early aspiration in liver abscess显示文摘AIM: To determine the predictive factors for early aspiration in liver abscess. METHODS: A retrospective analysis of all patients with liver abscess from 1995 to 2004 was performed. Abscess was diagnosed as amebic in 661 (68%) patients, pyogenic in 200 (21%), indeterminate in 73 (8%) and mixed in 32 (3%). Multiple logistic regression analysis was performed to determine predictive factors for aspiration of liver abscess. RESULTS: A total of 966 patients, 738 (76%) male, mean age 43 ± 17 years, were evaluated: 540 patients responded to medical therapy while adjunctive percutaneous aspiration was performed in 426 patients. Predictive factors for aspiration of liver abscess were: age ≥ 55 years, size of abscess ≥ 5 cm, involvement of both lobes of the liver and duration of symptoms ≥ 7 d. Hospital stay in the aspiration group was relatively longer than in the non aspiration group. Twelve patients died in the aspiration group and this mortality was not statistically significant when compared to the non aspiration group. CONCLUSION: Patients with advanced age, abscess size > 5 cm, both lobes of the liver involvement and duration of symptoms > 7 d were likely to undergo aspiration of the liver abscess, regardless of etiology. | Rustam Khan Saeed Hamid Shahab Abid Wasim Jafri Zaigham Abbas Mohammed Islam Hasnain Shan Shaalan Beg | 2008 | World Journal of Gastroenterology2008,14,13: | 8 |
| 10 | Cytokine- and chemokine-induced inflammatory colorectal tumor microenvironment: Emerging avenue for targeted therapy显示文摘Colorectal cancer(CRC)is a predominant life-threatening cancer,with liver and peritoneal metastases as the primary causes of death.Intestinal inflammation,a known CRC risk factor,nurtures a local inflammatory environment enriched with tumor cells,endothelial cells,immune cells,cancer-associated fibroblasts,immunosuppressive cells,and secretory growth factors.The complex interactions of aberrantly expressed cytokines,chemokines,growth factors,and matrix-remodeling enzymes promote CRC pathogenesis and evoke systemic responses that affect disease outcomes.Mounting evidence suggests that these cytokines and chemokines play a role in the progression of CRC through immunosuppression and modulation of the tumor microenvironment,which is partly achieved by the recruitment of immunosuppressive cells.These cells impart features such as cancer stem cell-like properties,drug resistance,invasion,and formation of the premetastatic niche in distant organs,promoting metastasis and aggressive CRC growth.A deeper understanding of the cytokineand chemokine-mediated signaling networks that link tumor progression and metastasis will provide insights into the mechanistic details of disease aggressiveness and facilitate the development of novel therapeutics for CRC.Here,we summarized the current knowledge of cytokine-and chemokine-mediated crosstalk in the inflammatory tumor microenvironment,which drives immunosuppression,resistance to therapeutics,and metastasis during CRC progression.We also outlined the potential of this crosstalk as a novel therapeutic target for CRC.The major cytokine/chemokine pathways involved in cancer immunotherapy are also discussed in this review. | Ajaz A.Bhat Sabah Nisar Mayank Singh Bazella Ashraf Tariq Masoodi Chandra P.Prasad Atul Sharma Selma Maacha Thasni Karedath Sheema Hashem Syed Besina Yasin Puneet Bagga Ravinder Reddy Michael P.Frennaux Shahab Uddin Punita Dhawan Mohammad Haris Muzafar A.Macha | 2022 | Cancer Communications2022,42,8: | 8 |
| 11 | Full field reservoir modeling of shale assets using advanced data-driven analytics显示文摘Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism(sorption process and flow behavior in complex fracture systems- induced or natural) leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this technology is that it incorporates the so-called 'hard data' directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The 'hard data' refers to field measurements during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of 'soft data'(non-measured, interpretive data such as frac length, width,height and conductivity) in the reservoir models. The study focuses on a Marcellus shale asset that includes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset. | Soodabeh Esmaili Shahab D.Mohaghegh | 2016 | Geoscience Frontiers2016,7,1: | 8 |
| 12 | Helicobacter pylori infection and micronutrient deficiencies显示文摘It is known that deficiencies of micronutrients due to infections increase morbidity and mortality. This phenomenon depicts itself conspicuously in developing countries.Deficiencies of iron, vitamins A, E, C, B12, etc are widely prevalent among populations living in the third world countries. Helicobacterpylori (Hpylori) infection has a high prevalence throughout the world. Deficiencies of several micronutrients due to Hpylori infection may be concomitantly present and vary from subtle sub-clinical states to severe clinical disorders. These essential trace elementsl micronutrients are involved in host defense mechanisms,maintaining epithelial cell integrity, glycoprotein synthesis,transport mechanisms, myocardial contractility, brain development, cholesterol and glucose metabolism. In this paper Hpyloriinfection in associaed with various micronutrients deficiencies is briefly reviewed. | Javed Yakoob Wasim Jafri Shahab Abid | 2003 | World Journal of Gastroenterology2003,9,10: | 7 |
| 13 | Effect of angioembolisation versus surgical packing on mortality in traumatic pelvic haemorrhage: A systematic review and meta-analysis显示文摘BACKGROUND: The management of complex pattern of bleeding associated with pelvic trauma remains a big challenge for trauma surgeons. We aimed to conduct a comprehensive meta-analysis to compare the outcomes of angioembolisation and pelvic packing in patients with pelvic trauma.METHODS: We conducted a systematic search of electronic information sources, including MEDLINE; EMBASE; CINAHL; the CENTRAL; the World Health Organization International Clinical Trials Registry; Clinical Trials.gov; ISRCTN Register, and bibliographic reference lists. The primary outcome was defined as mortality. Combined overall effect sizes were calculated using randomeffects models. Results are reported as the odds ratio(OR) and 95% confidence interval(CI).RESULTS: We identified 3 observational studies reporting a total of 120 patients undergoing angioembolisation(n=60) or pelvic packing(n=60) for pelvic trauma. Reporting of the Injury Severity Score(ISS) was variable, with higher ISS in the pelvic packing group. The risk of bias was low in two studies, and moderate in one. The pooled analysis demonstrated that angioembolisation did not significantly reduce mortality in patients with pelvic trauma compared to surgery(OR=1.99; 95% CI= 0.83–4.78, P=0.12). There was mild between-study heterogeneity(I^2=0%, P=0.65).CONCLUSION: Our analysis found no significant difference in mortality between angioembolisation and pelvic packing in patients with traumatic pelvic haemorrhage. The current level of evidence in this context is very limited and insufficient to support the superiority of a treatment modality. Future research is required. | Ahmed El Muntasar Ethan Toner Oddai A.Alkhazaaleh Danaradja Arumugam Nikhil Shah Shahab Hajibandeh Shahin Hajibandeh | 2018 | World Journal of Emergency Medicine2018,9,2: | 7 |
| 14 | Prevalence of non-Helicobacter pylori duodenal ulcer in Karachi,Pakistan显示文摘AIM: To determine the prevalence of non-Helicobacter pylori (H pylori)-related duodenal ulcer in patients with acid-peptic diseases.METHODS: Medical records of patients who attended the Gastroenterology Department at Aga Khan University Hospital from 1999 to 2001 and had endoscopic diagnosis of duodenal ulcers were reviewed. Duodenal ulcer associated with H pylori was diagnosed on the basis of endoscopy,rapid urease test and histopathology whereas histories of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) related duodenal ulcers. Non-H pylori, non-NSAID duodenal ulcers were those without H pylori infection and history of NSAID intake. Co-morbid conditions associated were noted.RESULTS: Of 2 260 patients, 10% (217/2 260) had duodenal ulcer. Duodenal ulcer related to H pylori infectionaccounted for 53% (116/217), NSAID-related 10% (22/217),non-H pylori non-NSAID 29% (62/217), and 8% (17/217) had both Hpyloriinfection and histories of NSAID intake. Fifteen percent (18/116)_patients had past histories of peptic ulcer disease in Hpyloriinfection, while 8% (5/62) in non-Hpylorinon-NSAID ulcer. Co-morbid conditions in H pylori infection were seen in 23% (27/116) and 34%(21/62) in non-H pylori non-NSAID ulcer.CONCLUSION: Incidence of H pylori infection related with duodenal ulcer is common. In the presence of co-morbids, non-Hpyloriand non-NSAID duodenal ulcer is likely to be present. | Javed Yakoob Wasim Jafri Nadim Jafri Muhammad Islam Shahab Abid Saeed Hamid Hasnain AliShah Hizbullah Shaikh | 2005 | World Journal of Gastroenterology2005,11,23: | 6 |
| 15 | Itopride for gastric volume,gastric emptying and drinking capacity in functional dyspepsia显示文摘AIM To study the effect of itopride on gastric accommodation, gastric emptying and drinking capacity in functional dyspepsia(FD). METHODS Randomized controlled trial was conducted to check the effect of itopride on gastric accommodation, gastric emptying, capacity of tolerating nutrient liquid and symptoms of FD. We recruited a total of 31 patients having FD on the basis of ROME III criteria. After randomization, itopride was received by 15 patients while 16 patients received placebo. Gastric accommodation was determined using Gastric Scintigraphy. ^(13) C labeled octanoic breadth test was performed to assess gastric emptying. Capacity of tolerating nutrient liquid drink was checked using satiety drinking capacity test. Theintervention group comprised of 150 mg itopride. Patients in both arms were followed for 4 wk. RESULTS Mean age of the recruited participant 33 years(SD = 7.6) and most of the recruited individuals, i.e., 21(67.7%) were males. We found that there was no effect of itopride on gastric accommodation as measured at different in volumes in the itopride and control group with the empty stomach(P = 0.14), at 20 min(P = 0.38), 30 min(P = 0.30), 40 min(P = 0.43), 50 min(P = 0.50), 60 min(P = 0.81), 90 min(P = 0.25) and 120 min(P = 0.67). Gastric emptying done on a sub sample(n = 11) showed no significant difference(P = 0.58) between itopride and placebo group. There was no significant improvement in the capacity to tolerate liquid in the itopride group as compared to placebo(P = 0.51). Similarly there was no significant improvement of symptoms as assessed through a composite symptom score(P = 0.74). The change in QT interval in itopride group was not significantly different from placebo(0.10). CONCLUSION Our study found no effect of itopride on gastric accommodation, gastric emptying and maximum tolerated volume in patients with FD. | Shahab Abid Wasim Jafri Maseeh Uz Zaman Rakhshanda Bilal Safia Awan Aamir Abbas | 2017 | World Journal of Gastrointestinal Pharmacology and Therapeutics2017,8,1: | 6 |
| 16 | Validity and cost comparison of ^(14)carbon urea breath test for diagnosis of H Pylori in dyspeptic patients显示文摘AIM: To validate and compare the cost of microdose 14C urea breath test (UBT) with histology and rapid urease test for the diagnosis of H Pylori. METHODS: Ninety-four consecutive patients with dyspeptic symptoms undergoing gastroscopy were enrolled. Gastric biopsies were taken for histology and rapid urease test. UBT was performed after gastroscopy by microdose 14C urea capsules. Sensitivity, specificity and accuracy of UBT were calculated and compared with histology and rapid urease test. Cost comparison of these tests was also performed. RESULTS: H pylori was diagnosed by histology and rapid urease test in 66 (70%) and 61 (65%) patients, while 14C UBT detected infection in 63 (67%). Accuracy of UBT was 93% in comparison with histology while its positive and negative predictive values were 97% and 84%, respectively. Comparison of 14C UBT with rapid urease test gives an accuracy of 96%, with positive and negative predictive values of 95% and 97%, respectively. These results were highly reproducible with a Kappa test (P value < 0.001). Cost of histology or rapid urease test with gastroscopy was 110 USD or 95 USD respectively while the cost of UBT was 15 USD. CONCLUSION: Microdose 14C UBT was comparable to histology and rapid urease test. 14C UBT is an economical, self sufficient and suitable test to diagnose active H pylori infection in less developed countries. | Shahid Rasool Shahab Abid Wasim Jafri | 2007 | World Journal of Gastroenterology2007,13,6: | 5 |
| 17 | Simulation of Vortex-Induced Vibrations of A Cylinder Using ANSYS CFX显示文摘In this paper, vortex-induced vibrations of a cylinder are simulated by use of ANSYS CFX simulation code. The cylinder is treated as a rigid body and transverse displacements are obtained by use of a one degree of freedom spring damper system. 2-D as well as 3-D analysis is performed using air as the fluid. Reynolds number is varied from 40 to 16000 approx., covering the laminar and turbulent regimes of flow. The experimental results of(Khalak and Williamson, 1997) and other researchers are used for validation purposes. The results obtained are comparable. | Abu Bakar IZHAR Arshad Hussain QURESHI Shahab KHUSHNOOD | 2014 | China Ocean Engineering2014,28,4: | 5 |
| 18 | Effect of water salinity on oil/brine interfacial behaviour during low salinity waterflooding: A mechanistic study显示文摘In recent years,controlling the salinity and composition of the injected water has become an emerging enhanced oil recovery(EOR)technique,often described as low salinity(LS)waterflooding.This work is done with the intention to contribute to the ongoing discussions about LS waterflooding mechanism(s).For this purpose,a series of different experiments were conducted.At first,the effect of salinity on the interfacial tension(IFT)and the contact angle was evaluated with a crude oil sample.Then to achieve more accurate results in observing oil/water interface,similar IFT experiments were also carried out on a synthetic oil containing asphaltenes.Thereafter,microscopic visualization using glass micromodel was performed on the interface of the synthetic oil sample and brines.Four brine solutions including Sea Water(SW),it's dilutions and formation water(FW)were used for various experiments.Finally,to investigate the presented mechanism by other authors,a series of Environmental Scanning Electron Microscopy(ESEM)analysis on the synthetic oil was carried out to understand better the phase behaviour after contacting both synthetic oil and water phases from the micromodel experiment.Based on the existing mechanism,there exists an optimal concentration beyond which dilution is no longer an effective process. | Peyman Rostami Mohammad Fattahi Mehraban Mohammad Sharifi Morteza Dejam Shahab Ayatollahi | 2019 | Petroleum2019,5,4: | 5 |
| 19 | The impact of connate water saturation and salinity on oil recovery and CO2 storage capacity during carbonated water injection in carbonate rock显示文摘Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively. | Mahmood Shakiba Masoud Riazi Shahab Ayatollahi Mostafa Takband | 2019 | Chinese Journal of Chemical Engineering2019,27,7: | 4 |
| 20 | Geostatistics Studies and Geochemical Modeling Based on Core Data,Sheytoor Iron Deposit,Iran显示文摘In general,the purpose of the mineralization modeling is the advancement of a mineral exploration project and ultimately,the extractive design of a deposit,which is one of the most important stages in mining engineering.Mineralization modeling is divided into two general categories,superficial and deep modeling.In surface modeling,the aim is finding abnormal locations in terms of mineralization at the study area,which is commonly used in the early stages of exploration as one of the means for locating exploratory boreholes.After drilling in the study area with the aim of identifying mineralization and reserve estimation it is necessary to obtain deep mineralization position and its geometric features,using statistical and modeling methods.Using mathematical,statistical and modeling methods,we can predict the position of iron mineralization in places where drilling is not done and eventually reach a three-dimensional model of the mineral materials underground.As a case study,the deep information about the boreholes of the sheytoor mining area in Yazd province of Iran was investigated.Iron mineralization was modeled as 2D cumulative model and 3D block model,and the results were presented.Finally the geochemical threshold and the anomalous limit of iron element are calculated by concentration-volume(C-V)fractal method in this deposit.Geochemical threshold and the anomalous limit for Fe in this deposit are 24.7%and 34.3%respectively. | Aref Shirazi Adel Shirazy Shahab Saki Ardeshir Hezarkhani | 2018 | Journal of Geological Resource and Engineering2018,6,3: | 4 |