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Fuel loading pattern optimization of a pressurized water reactor by varying internal weights-based particle swarm optimization

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Nuclear Science and Techniques 2018年第3期29卷 61-70页

作者： Aneela Zameer sikander m.mirza Asifullah Khan Furqan mir Department of Computer and Information Sciences Pakistan Institute of Engineering and Applied Sciences (PIEAS) Department of Physics and Applied mathematics Pakistan Institute of Engineering and Applied Sciences (PIEAS) Department of Nuclear Engineering Pakistan Institute of Engineering and Applied Sciences (PIEAS)

Fuel reload pattern optimization is essential for attaining maximum fuel burnup for minimization of generation cost while minimizing power peaking factor(PPF).The aim of this work is to carry out detailed assessment of particle swarm optimization(PSO) in the context of fuel reload pattern search. With astronomically large number of possible loading patterns, the main constraints are limiting local power peaking factor, fixed number of assemblies,fixed fuel enrichment, and burnable poison rods. In this work, initial loading pattern of fixed batches of fuel assemblies is optimized by using particle swarm optimization technique employing novel feature of varying inertial weights with the objective function to obtain both flat power profile and cycle k_(eff)>1. For neutronics calculation, PSU-LEOPARD-generated assembly depletiondependent group-constant-based ADD files are used. The assembly data description file generated by PSU-LEOPARD is used as input cross-section library to mCRAC code, which computes normalized power profile of all fuel assemblies of PWR nuclear reactor core. The standard PSO with varying inertial weights is then employed to avoid trapping in local minima. A series of experiments havebeen conducted to obtain near-optimal converged fuelloading pattern of 300 mWe PWR Chashma reactor. The optimized loading pattern is found in good agreement with results found in literature. Hybrid scheme of PSO with simulated annealing has also been implemented and resulted in faster convergence.

关键词： PWR Loading pattern optimization PSO PPF In-core fuel management

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Influence of thyroid volume reduction on absorbed dose in ^(131)I therapy studied by using Geant4 monte Carlo simulation

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Chinese Physics C 2014年第5期38卷 62-68页

作者： Ziaur Rahman sikander m mirza Waheed Arshed Nasir m mirza Waheed Ahmed Health Physics Division Pakistan Institute of Nuclear Science and Technology Department of Physics and Applied mathematics Pakistan Institute of Engineering and Applied Sciences

A simulation study has been performed to quantify the effect of volume reduction on the thyroid absorbed dose per decay and to investigate the variation of energy deposition per decay due to β- and γ-activity of 131I with volume/mass of thyroid, for water, ICRP- and ICRU-soft tissue taken as thyroid material. A monte Carlo model of the thyroid, in the Geant4 radiation transport simulation toolkit was constructed to compute the β- and γ-absorbed dose in the simulated thyroid phantom for various values of its volume. The effect of the size and shape of the thyroid on energy deposition per decay has also been studied by using spherical, ellipsoidal and cylindrical models for the thyroid and varying its volume in 1-25 cm3 range. The relative differences of Geant4 results for different models with each other and mCNP results lie well below 1.870%. The maximum relative difference among the Geant4 estimated results for water with ICRP and ICRU soft tissues is not more than 0.225%. S-values for ellipsoidal, spherical and cylindrical thyroid models were estimated and the relative difference with published results lies within 3.095%. The absorbed fraction values for beta particles show a good agreement with published values within 2.105% deviation. The Geant4 based simulation results of absorbed fractions for gammas again show a good agreement with the corresponding mCNP and EGS4 results （±6.667%） but have 29.032% higher values than that of mIRD calculated values. Consistent with previous studies, the reduction of the thyroid volume is found to have a substantial effect on the absorbed dose. Geant4 simulations confirm dose dependence on the volume/mass of thyroid in agreement with mCNP and EGS4 computed values but are substantially different from mIRD8 data. Therefore, inclusion of size/mass dependence is indicated for 131I radiotherapy of the thyroid.

关键词： mean absorbed dose rate Geant4 monte Carlo simulation and 131I therapy

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Evaluation of Corrosion Product Activity in a Typical PWR with Extended Cycles and Flow Rate Perturbations

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World Journal of Nuclear Science and Technology 2017年第1期7卷 24-34页

作者： Rubina Nasir sikander m. mirza Nasir m. mirza Department of Physics Air University Islamabad Pakistan Department of Physics & Applied mathematics Pakistan Institute of Engineering & Applied Sciences Islamabad Pakistan

Effect of flow rate perturbations has been studied using the modified computer program CPAIR-P for time dependent corrosion rates in Pressurized Water Reactors (PWRs) having extended cycles. In these simulations, a decrease in the corresponding saturation values of corrosion product activity (CPA) is observed for higher pH values. Comparison of CPA’s behavior has been done for constant flow-rate case as well as for transients with elevated 10B levels (~40%) in dissolved boric acid in coolant in two operating cycles. When the flow rate is decreased in the first cycle, the saturation value of CPA attains new higher values. Also, in the second operating cycle, the saturation values are about 12% higher when compared with the values in the first cycle.

关键词： PWRs Corrosion Products Enriched Boric Acid Extended Cycles Flow Rate Perturbations

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Exosomes derived from tumor adjacent fibroblasts efficiently target pancreatic tumors

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Acta Pharmaceutica Sinica B 2024年第7期14卷 3009-3026页

作者： Saini Setua Shabia Shabir Poornima Shaji Ana martinez Bulnes Anupam Dhasmana Swathi Holla Nivesh K.mittal Nirakar Sahoo Tripti Saini Francesco Giorgianni mohammad sikander Andrew E.massey Bilal B.Hafeez manish K.Tripathi Vincent P.Diego meena Jaggi Junming Yue Nadeem Zafar murali m.Yallapu Stephen W.Behrman Sheema Khan Subhash C.Chauhan Department of Pharmaceutical Sciences College of Pharmacyand College of MedicineUniversity of Tennessee Health Science Center(UTHSC)MemphisTN 36163USA Department of Computer Science Islamic University of Science and TechnologyAwantiporaJ&K 192122India Department of Immunology and microbiology School of MedicineUniversity of Texas Rio Grande ValleyMcAllenTX 78504USA South Texas Center of Excellence in Cancer Research School of Medicinethe University of Texas Rio Grande ValleyMcAllenTX 78504USA Himalayan School of Biosciences and Cancer Research Institute Himalayan Institute of Medical SciencesSwami Rama Himalayan UniversityDehradun 248016India Plough Center for Sterile Drug Delivery Solutions UTHSCMemphisTN 38104USA Department of Biology College of SciencesUTRGVMcAllenTX 78539USA National Institute of Biomedical Imaging and Bioengineering(NIBIB) National Institutes of HealthBethesdaMD 20892USA South Texas Diabetes and Obesity Institute UTRGVMcAllenTX 78504USA Dept.of Laboratory medicine&Pathology University of WashingtonSeattleWA 98195USA Department of Surgery Baptist Memorial Medical EducationBaptist Memorial HospitalMemphisTN 38120USA Baptist Health Sciences University MemphisTN 38104USA

The application of extracellular vesicles,particularly exosomes(EXs),is rapidly expanding in the field of medicine,owing to their remarkable properties as natural carriers of biological *** study investigates utilization of exosomes derived from stromal cells of tumor adjacent normal tissues(NAF-EXs)for personalized medicine,which can be derived at the time of diagnosis by endoscopic ***,we show that exosomes(EXs)derived from NAFs demonstrate differential bio-physical characteristics,efficient cellular internalization,drug loading efficiency,pancreatic tumor targeting and delivery of ***-derived EXs(NAF-EXs)were used for loading ormeloxifene(ORm),a potent anti-cancer and desmoplasia inhibitor as a model *** found that ORm maintains normal fibroblast cell phenotype and renders them incompatible to be triggered for a CAF-like phenotype,which may be due to regulation of Ca^(2+) influx in fibroblast ***-EXs-ORm effectively blocked oncogenic signaling pathways involved in desmoplasia and epithelial mesenchymal transition(EmT)and repressed tumor growth in xenograft mouse *** conclusion,our data suggests preferential tropism of NAF-EXs for PDAC tumors,thus imply feasibility of developing a novel personalized medicine for PDAC patients using autologous NAF-EXs for improved therapeutic outcome of anti-cancer ***,it provides the opportunity of utilizing this biological scaffold for effective therapeutics in combination with standard therapeutic regimen.

关键词： Pancreatic cancer Tumor adjacent normal tissue fibroblasts(NAF) Desmoplasia Extracellular vesicles Exosomes Tumor targeting Ormeloxifene Personalized medicine

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metabolic investigations in patients with hepatitis B and C

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World Journal of Gastroenterology 2010年第5期16卷 603-607页

作者： Abdul Aziz mastoi Bikha Ram Devrajani Syed Zulfiquar Ali Shah Qasim Rohopoto sikander Ali memon marya Baloch Ghulam Ali Qureshi Waqas Sami m.A.Kazi Institute of Chemistry University of SindJamshoro 75000Pakistan Department of medicine Liaquat University of Medical and Health SciencesJamshoro 75000Pakistan medical Research Centre Liaquat University of Medical and Health SciencesJamshoro 75000 Pakistan Department of Biochemistry University of Health SciencesLahore 54600Pakistan

AIm:To investigate the similarities and dissimilarities in patients with hepatitis B and hepatitis C,clinically and metabolically. mETHODS:Fifty patients with hepatitis B virus and hepatitis C virus infection were included in this study, along with fifty healthy controls for comparison *** blood(10 mL)samples from patients and healthy subjects were collected and made to clot before serum was separated and immediately levels of the enzymes,alkaline phosphatase(ALK),creatinine phosphokinase(CPK),lactate dehydrogenase (LDH),serum glutamate oxaloacetate transaminase(sGOT)and serum glutamate pyruvate transaminase(sGPT)were determined by a kit *** total con-tent of each metal the serum samples were analyzed using atomic absorption *** of cholesterol,triglycerides,urea,creatinine and uric acid were determined using a kit method on microlab 300. RESULTS:Serum magnesium and copper levels remained unchanged,whereas the concentration of zinc decreased and iron increased significantly in both groups of *** antioxidant activity was significantly decreased in both hepatitis B and *** the enzymes analyzed,ALK,s-GPT,LDH and s-GOT were all significantly increased in both patients with hepatitis B and C whereas CPK was significantly decreased in patients with hepatitis B and remained unchanged in patients with hepatitis C. CONCLUSION:The information accumulated by this study will help provide a better understanding of involved metabolic processes in order to design appropriate therapeutic approaches for treating these patients,so they can recover and lead normal lives.

关键词： Hepatitis B virus Hepatitis C virus Antioxidant activity metal content Enzyme activity

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光场粒子图像测速技术在超音速射流中的实验研究和验证

光场粒子图像测速技术在超音速射流中的实验研究和验证

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作者： sikander Sheikh 上海交通大学

学位级别：硕士

光场粒子图像测速(light-field particle image velocimetry,LFPIV)是一种新兴且有发展潜力的单相机三维流场测量技术。现存的其他三维粒子图像测速技术有以下几个局限性:(1)实验设备复杂,(2)设备占用空间大,(3)处理时间长和(4)基于多... 详细信息

光场粒子图像测速(light-field particle image velocimetry,LFPIV)是一种新兴且有发展潜力的单相机三维流场测量技术。现存的其他三维粒子图像测速技术有以下几个局限性:(1)实验设备复杂,(2)设备占用空间大,(3)处理时间长和(4)基于多相机系统。本文提出利用LFPIV来规避上述局限性。文中介绍了使用LFPIV来精确获取超声速射流三维速度场的实验,借以初次验证LFPIV在高速可压缩流体中的可行性。在此之前,LFPIV仅被应用在低速射流和涡流中。为了验证整个系统的功效,采取了以下的验证手段:(1)定性验证,即对比纹影结果中超声速射流的激波结构和马赫环以及(2)定量验证,即对比二维PIV中超声速射流的剖面速度分布图和马赫数分布,两者结果的误差约为1%。在本文涉及的研究中,超音速喷嘴是基于双半径法和特征线法来设计的。为了验证喷嘴出口处均匀激波的存在,画出了喷嘴的二维计算模型并在此基础上通过ANSYS来模拟。同时还在低、中、高的精细度条件下进行了网格无关性测试。在本文的实验中,使用了总计三套设备来做定性和定量的分析:(1)纹影实验,(2)二维PIV(粒子为直径1μm的氧化铝颗粒)和(3)LFPIV实验(粒子为直径0.5μm的氧化铝颗粒)。基于镜面纹影的实验研究使用了水平和竖直两组刀片,其结果表明所设计喷嘴外的流动具有过膨胀、完美膨胀和欠膨胀的特性。结果也可用来提取激波几何结构,以便在之后的实验中对比定性验证LFPIV的测量。利用二维PIV对该超音速射流做实验研究,从150个拍摄处理得到的瞬态速度场中得出平均速度在y方向上和x方向上的值。其中,计算获得的y方向上平均马赫数为0.9-1.2,整个射流(含外部边界区域)的速度范围约为280m/s至384m/s。最后,利用新兴且具有创新性的LFPIV初测测量超音速射流,其结果马赫数约为0.9-1.2,整个射流(含外部边界区域)的速度范围为231m/s至385m/s。此结果通过与二维PIV结果的对比得到了验证。此外,还在概率分布函数和累计概率分布函数上开展了速度差异分析。二维PIV与LFPIV的速度绝对值差异大约为1%,马赫数分布差异大约为1.2%,表明了两者的结果具有相似性、可比性。本文的创新点在于:(1)首次验证了LFPIV在超声速可压缩流体中的应用,(2)设计了超声速喷嘴,并基于此开展纹影、二维PIV和三维PIV实验,(3)在受限光学窗口系统中使用LFPIV,即用单相机实现超音速射流三维速度场测量,(4)通过紧凑的单相机系统获得了与其他多相机三维PIV技术可比的结果,(5)定量定性地比较分析了二维PIV和LFPIV所获的结果。

关键词：光场成像三维粒子图像测速技术超音速射流纹影二维PIV 光场PIV

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不同耕作措施下夏玉米生长季农田CO_2排放速率及其与土壤温度的关系

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西北农业学报 2013年第6期22卷 53-59页

作者：禄兴丽 sikander Khan Tanveer 廖允成温晓霞西北农林科技大学农学院陕西杨凌712100

采用定位试验,系统研究翻耕(CT)、旋耕(RT)、免耕不覆盖(NT)3种不同耕作措施下土壤CO2排放速率,并对CO2排放速率和10cm土壤温度进行回归模拟。结果表明:夏玉米生育期CO2排放速率表现为翻耕(CT)>旋耕(RT)>免耕不覆盖(NT),平均分别为585.... 详细信息

采用定位试验,系统研究翻耕(CT)、旋耕(RT)、免耕不覆盖(NT)3种不同耕作措施下土壤CO2排放速率,并对CO2排放速率和10cm土壤温度进行回归模拟。结果表明:夏玉米生育期CO2排放速率表现为翻耕(CT)>旋耕(RT)>免耕不覆盖(NT),平均分别为585.675、457.875和184.95mg·m-2·h-1。并且3种耕作措施之间差异均达到显著水平(Pm地温相关系数分别为0.624、0.609和0.606。CO2排放速率和土壤温度呈指数函数关系(Pm地温对夏玉米生育期农田CO2排放通量进行估算表明,CT、RT和NT处理CO2排放量分别为1.47、1.15和0.46kg·m-2。

关键词：耕作措施夏玉米土壤CO2排放速率土壤温度

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新疆地区幽门螺杆菌cagA、vacA基因型与常见胃病的关系研究

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新疆医科大学学报 2016年第2期39卷 160-163,168页

作者：阿孜尔古丽.阿布都克日木许海峰刘玉梅娜迪热.铁列吾汗布海里且木.吾甫尔斯坎德尔.努尔买买提德力夏提.依米提新疆医科大学基础医学院病原生物学教研室乌鲁木齐830011 克拉玛依市中心医院检验科新疆克拉玛依834000 新疆医科大学第一附属医院检验中心乌鲁木齐830054 新疆医科大学第一附属医院超声诊断科乌鲁木齐830054 新疆维吾尔自治区人民医院消化内科乌鲁木齐830001 新疆维吾尔自治区人民医院胃肠外科乌鲁木齐830001

目的探讨新疆维吾尔族和汉族患者的幽门螺杆菌分离株cagA、vacA基因型与常见胃病的相关性。方法采用聚合酶链反应(PCR)方法检测92例胃病患者(慢性胃炎、萎缩性胃炎、胃溃疡和胃癌)的幽门螺杆菌vacA和cagA基因型。结果维吾尔族与汉族胃... 详细信息

目的探讨新疆维吾尔族和汉族患者的幽门螺杆菌分离株cagA、vacA基因型与常见胃病的相关性。方法采用聚合酶链反应(PCR)方法检测92例胃病患者(慢性胃炎、萎缩性胃炎、胃溃疡和胃癌)的幽门螺杆菌vacA和cagA基因型。结果维吾尔族与汉族胃病患者中幽门螺杆菌cagA基因检出率高,均为84.8%,但cagA基因的分布无明显差异。在92株菌株中vacA m2、s1a、m1b、s2的检出率分别为67.4%、61.9%、18.5%和4.3%。维、汉族胃病患者最常见的vacA基因型为s1a、m2。维吾尔族胃癌患者vacA m2基因型检出率高于汉族胃癌患者,而vacA m1b基因型检出率低于汉族患者。汉族胃溃疡患者vacA m2基因型检出率显著高于胃癌患者;各胃病组vacA m1b基因型检出率从高到底依次为慢性胃炎、胃溃疡、胃癌,差异有统计学意义(P<0.05)。结论胃癌患者的vacA基因型分布可能与民族的不同而有区别,此结果可能为未来幽门螺杆菌的基因治疗提供一定的研究基础。

关键词：幽门螺杆菌 cagA基因 vacA基因 PCR

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