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Comparative assessment of mechanical and chemical fluid diversion techniques during hydraulic fracturing in horizontal wells

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Petroleum Science 2023年第6期20卷 3582-3597页

作者： Maunish S.Shah subhash n.Shah Drilling Cementingand Stimulation Research CenterDepartment of Petroleum EngineeringSchool of Energy TechnologyPandit Deendayal Energy UniversityRaisanGandhinagarGujaratIndia Mewbourne School of Petroleum and Geological Engineering The University of OklahomaNormanOKUSA

The application of fluid diversion during hydraulic fracturing is an evolving technology and has become popular amongst E&P operators over the past few *** primary objective of the fluid diversion is to improve hydraulic fracturing treatment by increasing stimulated reservoir volume and improving hydrocarbon *** is possible by achieving any of the following objectives:creating uniform distribution of treatment slurry within the target zone;treating unstimulated and under-stimulated zones;or by increasing fracture density by creating a complex fracture *** fluid diversion application is also helpful in decreasing the number of stages(by increasing stage length)for multi-stage plug-n-perf(PnP)fracturing *** is also applied to prevent fracture-driven interactions between adjacent wells,which is currently a major issue,especially in *** addition,for successful refracturing treatment,the diverter application is essential for isolating the existing fractures and redirecting the treatment slurry to the desired unstimulated *** diversion methods can be broadly categorized into the mechanical and chemical *** established mechanical diversion techniques are frac plugs,expandable casing patches,expandable liners,swellable packers,straddle packer assembly,sand plugs,frac sleeves,perforation ball sealers,and limited entry *** different chemical diversion techniques are particulates,fibers,gels,surfactants,perforation pods,and composite *** paper describes the current status of established mechanical and chemical diverter technologies and examines their comparative advantages and *** techniques are suitable for diverter application,but the technique is selected based on the desired objective and conditions of the wellbore and *** general guidelines for selecting diversion techniques and operational considerations are also provided in the *** diagnosis of diversion treatme

关键词： Fluid diversion Diverter Diverting agents Multi-stage fracturing Hydraulic fracturing Horizontal well

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In vitro antioxidant and antimicrobial activity cycloart-23-ene-3β,25-diol(B2) isolated from Pongamia pinnata(***)

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Asian Pacific Journal of Tropical Medicine 2011年第11期4卷 910-916页

作者： Sachin L Badole Anand A Zanwar Abhijeet n Khopade subhash L Bodhankar Department of Pharmacology Poona College of PharmacyBharati Vidyapeeth UniversityPaud RoadErandwanePuneMaharashtraIndia

Objective:To evaluate the in-vitro antioxidant and antimicrobial activity of cvcloart-23- ene-3β,25-diol(called as B2) isolated from stem bark of Pongamia ***:In vitro antioxidant activity of B2 was determined by methods for determination of Dl’PH radical scavenging,reducing power,superoxide anion radical scavenging,hydroxyl radical scavenging, hydrogen peroxide scavenging,metal chelating and nitric oxide radical scavenging at the doses of 20.***.60.80 and 100μg/mL,respectively.3 -tocopherol with same concentration was used as a standard *** vitro antimicrobial activity of B2 was determined by cup plate method in different concentration range of 10-100μg/***:The results indicated that dose dependent%reduction against DPPH radical,reducing power,superoxide anion radical scavenging,hydroxyl radical scavenging,metal chelating,hydrogen peroxide scavenging and nitric oxide radical scavenging by B2 andβ-***:It is concluded that cycloart 23-ene-3β,25 diol(B2) showed dose dependent antioxidant activity.B2 showed more DPPH radical scavenging,reducing power,superoxide scavenging,hydroxyl radical scavenging, metal chelating scavenging,hydrogen peroxide radical scavenging and nitric oxide radical scavenging activity thanβ-tocopherol and in case of antimicrobial activity B2 exhibited broad-spectrum activ ity against bacteria and strong activity against yeast type of fungi.

关键词： Antibacterial activity Antifungal activity In vitro antioxidant Cycloart-23-ene-3β 25-diol(B2) Pongamia pinnata

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Observer-based Adaptive Optimal Control for Unknown Singularly Perturbed nonlinear Systems With Input Constraints

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IEEE/CAA Journal of Automatica Sinica 2017年第1期4卷 48-57页

作者： Zhijun Fu Wenfang Xie subhash Rakheja Jing na College of Mechanical Engineering Zhejiang University of Technology Department of Mechanical & Industrial Engineering Concordia University Faculty of Mechanical & Electrical Engineering Kunming University of Science & Technology

This paper introduces an observer-based adaptive optimal control method for unknown singularly perturbed nonlinear systems with input constraints. First, a multi-Time scales dynamic neural network MTSDnn observer with a novel updating law derived from a properly designed Lyapunov function is proposed to estimate the system states. Then, an adaptive learning rule driven by the critic nn weight error is presented for the critic nn, which is used to approximate the optimal cost function. Finally, the optimal control action is calculated by online solving the Hamilton-Jacobi-Bellman HJB equation associated with the MTSDnn observer and critic nn. The stability of the overall closed-loop system consisting of the MTSDnn observer, the critic nn and the optimal control action is proved. The proposed observer-based optimal control approach has an essential advantage that the system dynamics are not needed for implementation, and only the measured input U+002F output data is needed. Moreover, the proposed optimal control design takes the input constraints into consideration and thus can overcome the restriction of actuator saturation. Simulation results are presented to confirm the validity of the investigated approach. © 2014 Chinese Association of Automation.

关键词： Closed loop systems Cost functions Lyapunov functions neural networks nonlinear systems Optimal control systems Perturbation techniques

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Variations in body melanisation, ovariole number and fecundity in highland and lowland populations of Drosophila melanogaster from the Indian subcontinent

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Insect Science 2008年第6期15卷 553-561页

作者： subhash Rajpurohit Ravi Parkash Seema Ramniwas Shama Singh Department of Biochemistry and Genetics Maharshi Dayanand University Rohtak 124001 India

We investigated geographical variations in three fitness-related traits （body melanisation, ovariole number and fecundity） in laboratory-reared offspring of 10 populations of Drosophila melanogaster. The populations were collected from adjacent lowland and highland localities （-80-100 km apart） in the tropical as well as subtropical regions （11.15-31.06°n） covering a linear distance about 3 000 kilometers from south to north on the Indian subcontinent. Persistence of within- as well as between-population differences at 21 ℃ suggest that observed variations in fitness-related traits have a genetic basis. Populations from higher altitudes showed consistently higher trait values （1.4-fold increase） as compared with their corresponding lowland populations. By contrast, latitudinal variations were about two-fold higher across the entire continent. Along latitude as well as altitude, population means showed higher correlation values （r 〉 0.98） between all the three fitness traits. However, on the basis of within-population analysis （assorted darker and lighter flies）, changes in body melanisation were significantly correlated with fecundity but not with ovariole number. Thus, analysis of within-population trait variability should be preferred as compared with data on population means for adaptive significance of fitness-related traits. In the present study, the role of climatic selection is evident from regression analysis with changes in annual average temperature of the sites of origin of populations along latitude as well as altitude.

关键词： altitude body melanisation Drosophila melanogaster fecundity latitude ovariole number

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Improved thermoelectric property of cation-substituted CaMnO_3

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Chinese Physics B 2015年第9期24卷 542-547页

作者： Pradeep Kumar subhash C.Kashyap Vijay Kumar Sharma H.C.Gupta Department of Physics Shyam Lal CollegeUniversity of Delhi Department of Physics Indian Institute of Technology Delhi

Single-phase pristine and cation-substituted calcium manganite（Ca1-xBixMn1-yVyO3-δ） polycrystalline samples were synthesized by the solid state reaction technique. Their thermoelectric properties were measured by a set up that was designed and assembled in the laboratory. The Ca1-x BixMn1-yVyO3-δsample with x = y = 0.04 has shown a power factor（S^2σ） of 176 μW/m/K^2 at 423 K, which is nearly two orders of magnitude higher than that of the pristine sample（2.1 μW/m/K2）. The power factor of the substituted oxide remains almost temperature independent as the Seebeck coefficient increases monotonically with temperature, along with the simultaneous decrease in electrical resistivity which is attributed to enhanced electron density due to co-doping of bismuth and vanadium and grain boundary scattering. These cation-substituted calcium manganites can be used as a potential candidate for an n-type leg in a thermoelectric generator（module）.

关键词： thermoelectric materials solid state reaction Seebeck coefficient power factor

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Potential of conservation tillage and altered land configuration to improve soil properties,carbon sequestration and productivity of maize based cropping system in eastern Himalayas,India

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International Soil and Water Conservation Research 2021年第2期9卷 279-290页

作者： Gulab Singh Yadav Anup Das subhash Babu Kamal Prasad Mohapatra Rattan Lal Dipjyoti Rajkhowa Indian Council of Agricultural Research(ICAR) Research Complex for North Eastern HillRegionTripura CentreTripuraIndia ICAR eIndian Agricultural Research Institute New DelhiIndia ICAR-national Bureau of Plant Genetic Resources New DelhiIndia Carbon Management and Sequestration Center Ohio State UniversityColumbusUSA ICAR Research Complex for nEH Region Nagaland CentreNagalandIndia

Poor soil properties especially low soil organic carbon(SOC)and nutrient and water retention capacities are major concern for sustainable agriculture in *** experiments were conducted to assess the effects of six combinations of tillage[conventional tillage(CT)and no-till(nT)]and land configurations[flat bed planting(FB),ridge and furrow planting(RF),and raised bed planting(RB)]on productivity and carbon(C)-sequestration potential of maize[(Zea mays L.)for green-cob in summer]-maize(for grains in rainy season)-field pea[(Pisum sativum *** winter]cropping system under humid mildtropical climate of Tripura,*** maize under nT-FB in 2012 and nT-RF in 2013 produced significantly higher green cob yield than that under ***,in rainy season,CT produced higher maize grain yield than nT *** pea seed yield was significantly the highest under *** two cropping cycles,nT systems had higher available n,P,K and 18.6e31.4%higher soil moisture content after rainy season maize than CT *** highest SOC-stock(0e30 cm)was observed under nT-FB,whereas,SOC-sequestration rate was maximum under nT-RB(0.85 Mg ha1 year1).Therefore,nT based systems can enhance the productivity and improve SOC-sequestration in cultivated soils of eastern ***,study recommended adoption of nT-RB/nT-FB to raise maize-maize-field pea system for improving productivity,improving C-sequestration and soil properties in the eastern Himalayas and similar eco-regions elsewhere.

关键词： Soil fertility Carbon sequestration Soil moisture Low productivity Hill ecosystem

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Reproductive phenology of Calophyllum inophyllum in Yeppoon, Australia and Meegoda Western Province, Sri Lanka

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Journal of Forestry Research 2011年第4期22卷 615-619页

作者： subhash Hathurusingha nanjappa Ashwath Kolitha Wijesekara David Midmore Centre for Plant and Water Science CQ University Rockhampton 4702 Australia Faculty of Science and Technology Uva Wellassa University Badulla 90000 Sri Lanka

Reproductive phenology of multiple use native plant Calo- phyllum inophyllum L. was studied in Yeppoon （23°7＇60＂ S, 150°43＇60＂ E）, northern Australia （southern hemisphere） and in Meegoda （6°18＇51＂n, 80°31＇3＂E）, Sri Lanka （northern hemisphere）. C. inophyllum trees in Yeppoon, Australia had relatively shorter flowering periods, shorter floral life spans, longer fruit life spans, smaller flowers and larger fi＇uits compared to those in Meegoda, Sri Lanka. Although the number of flower buds/ inflorescence was comparatively higher in Meegoda, C. inophyllum trees in both locations had similar mean number of mature fruits/cluster due to the higher floral abscission in C. inophyllum trees at Meegoda. Despite having a comparatively lower fruit yield （664 000 fruts·ha^-1·a^-1）, C. inophyllum trees in Yeppoon hdd lligher kernel weights （2988.0±853.2 kg·ha^-1·a^-1） and oil yields （1 33226±380.5 kg·ha^-1·a^-1） compared to those in Meegoda.

关键词： Calophyllum inophyllum Flowering F ruCting Inflorescence Phenology

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Tissue-specific Temporal Exome Capture Revealed Muscle-specific Genes and SnPs in Indian Buffalo(Bubalus bubalis)

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Genomics, Proteomics & Bioinformatics 2012年第2期10卷 107-113页

作者： subhash J.Jakhesara Viral B.Ahir Ketan B.Padiya Prakash G.Koringa Dharamshibhai n.Rank Chaitanya G.Joshi Department of Animal Biotechnology College of Veterinary Science&Animal HusbandryAnand Agricultural UniversityAnand 388001India Department of Animal Genetics and Breeding College of Veterinary Science&Animal HusbandryAnand Agricultural UniversityAnand 388001India

Whole genome sequencing of buffalo is yet to be completed, and in the near future it may not be possible to identify an exome （coding region of genome） through bioinformatics for designing probes to capture it. In the present study, we employed in solution hybridization to sequence tissue specific temporal exomes （TST exome） in buffalo. We utilized cDnA prepared from buffalo muscle tissue as a probe to capture TST exomes from the buffalo genome. This resulted in a prominent reduction of repeat sequences （up to 40%） and an enrichment of coding sequences （up to 60%）. Enriched targets were sequenced on a 454 pyro-sequencing platform, generating 101,244 reads contain- ing 24,127,779 high quality bases. The data revealed 40,100 variations, of which 403 were indels and 39,218 SnPs containing 195 nonsyn- onymous candidate SnPs in protein-coding regions. The study has indicated that 80% of the total genes identified from capture data were expressed in muscle tissue. The present study is the first of its kind to sequence TST exomes captured by use of cDnA molecules for SnPs found in the coding region without any prior sequence information of targeted molecules.

关键词： Hybridization Exome SnP, Bubalus bubalis Temporal gene expression 454 Sequencing

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一种基于率相关回滞的压电带载驱动建模方法

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华南理工大学学报（自然科学版） 2018年第8期46卷 57-63页

作者：冯颖冯俊杰 subhash Rakheja 姜辉华南理工大学自主系统与网络控制教育部重点实验室//自动化科学与工程学院广东广州510640 康科迪亚大学工程与计算机科学学院加拿大蒙特利尔魁北克H3G1M8 桂林电子科技大学电子工程与自动化学院广西桂林541004

以压电驱动器为代表的智能材料驱动器,以其能实现微纳米级精密驱动的优势逐步在精密装备中得以应用,但其内部的回滞非线性在微纳米级驱动性能要求下成为限制精度提升的瓶颈.文中以压电驱动器为研究对象,在不同输入信号频率的条件下研究... 详细信息

以压电驱动器为代表的智能材料驱动器,以其能实现微纳米级精密驱动的优势逐步在精密装备中得以应用,但其内部的回滞非线性在微纳米级驱动性能要求下成为限制精度提升的瓶颈.文中以压电驱动器为研究对象,在不同输入信号频率的条件下研究其带载输出特性,结合压电驱动器的机电特性,提出了一种压电驱动系统带载环境下的建模方法.该方法基于率相关Prandtl-Ishlinskii(RDPI)回滞模型,同时考虑工作频率增加时载荷对系统输出所造成的影响,以克服常规RDPI回滞模型无法表征带载条件下输出特性的局限.结合压电驱动系统带载2. 94 n工作条件,完成1～80 Hz驱动频率范围的实验验证.结果表明,文中提出的建模方法能有效地反映压电驱动器在带载环境下的输入-输出特性.

关键词：压电驱动器回滞动态特性建模

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Surface engineering of ZnO electrocatalyst by n doping towards electrochemical CO_(2) reduction

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Journal of Energy Chemistry 2024年第1期88卷 71-81,I0002页

作者： Rohini subhash Kanase Getasew Mulualem Zewdie Maheswari Arunachalam Jyoti Badiger Suzan Abdelfattah Sayed Kwang-Soon Ahn Jun-Seok Ha Uk Sim Hyeyoung Shin Soon Hyung Kang Department of Interdisciplinary Program for Photonic Engineering Chonnam National UniversityGwangju 61186Republic of Korea Graduate School of Energy Science and Technology(GEST) Chungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Department of Chemistry Education and Optoelectronic Convergence Research Center Chonnam National UniversityGwangju 61186Republic of Korea Department of Advanced Chemicals and Engineering Chonnam National UniversityGwangju 61186Republic of Korea School of Chemical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Energy Engineering Korea Institute of Energy Technology(KENTECH)Naju 58217Republic of Korea

The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(n)doping on the ECR activity of ZnO electrocatalysts was ***,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the n-doping *** an increase in the n-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped ***,the ECR performance of Zn O electrocatalysts with different n-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR *** the ECR activity increased after a small amount of n doping,it decreased for higher n doping *** them,the n:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V *** hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the n:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of n:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of n:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by n doping.

关键词： ZnO n-doped ZnO Gas-diffusion electrode CO Selectivity Electrochemical CO_(2)reduction

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