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Petroleum 2021年第4期7卷 407-413页

作者： Md Nahin mahmood Boyun Guo Department of Petroleum and Mining Engineering Chittagong University of Engineering&TechnologyChattogram4349Bangladesh Department of Petroleum Engineering University of LouisianaLafayetteLA70504USA

Development of marine gas hydrate resources presents a huge challenge to the energy industry owing to the well production complications such as wellbore collapse,sand production,and low *** lateral wells(RLW)and horizontal snake wells(HSW)have been proposed separately to mitigate these *** compare the productivity potentials of these two types of wells using the recently developed analytical models and field case data from a gas hydrate reservoir in the South China *** is concluded that RLW will yield slightly higher gas productivity than HSW under similar con*** analysis with the well models indicates that the productivity of RLW is directly proportional to the number of laterals,length of laterals,and radius of laterals,while the productivity of HSW is directly proportional to the length and radius of the horizontal *** decision of using RLW or HSW can be made based on economic analysis of well completion and production,which should be addressed in future studies.

关键词： Natural gas hydrate Radial lateral wells Horizontal snake wells Productivity

Causes of recurring drought patterns in Xinjiang, China

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Journal of Arid Land 2010年第4期2卷 279-285页

作者： Rashed mahmood Babar KHAN Nansen-Zhu International Research Center Institute of Atmospheric Physics CAS Xinjiang Institute of Ecology and Geography CAS

Xinjiang Uygur Autonomous Region of China, with its unique topography and geographical location receives very less precipitation in summer as compared with other parts of China. The region is a land locked where moisture is supplied only by westerly winds from Atlantic Ocean as the moisture coming from Indian Ocean is mostly blocked by the Himalayas Range and the Tibetan plateau. In such a scenario, Xinjiang faces severe drought conditions offering significant challenges to water management. In this paper, we analyzed the drought periods in Xinjiang and discussed the various factors that might have influenced precipitation over the past forty-four years. For this purpose, we defined three periods of consecutive four years for high and low precipitation intensities. The average observed precipitation was 1.05 mm/day and 0.7 mm/day in summer (June-July-August) for the Tianshan Mountain region and Junggar Basin of Xinjiang, respectively. The drought conditions indicated that high sea level pressure, wind divergence and low convection were the prominent features that caused the droughts, which often do not allow the condensation process to coagulate the tiny water droplets into relatively large raindrops reducing the amount of precipitation in the region. The period of 1983-1986 is the lowest precipitation interval indicating the severe drought in the western Xinjiang (i.e western Tianshan Mountain region), for which, less moisture availability, strong divergence and less convection could be the most influencing factors.

关键词： Xinjiang drought topography moisture availability convection raindrops divergence

Hybrid Dynamic Neural Network and PID Control of Pneumatic Artificial Muscle Using the PSO Algorithm

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International Journal of Automation and computing 2020年第3期17卷 428-438页

作者： Mahdi Chavoshian Mostafa Taghizadeh mahmood Mazare School of Mechanical Engineering Sh.Beheshti UniversityTehran 16589-53571Iran

Pneumatic artificial muscles(PAM)have been recently considered as a prominent challenge regarding pneumatic actuators specifically for rehabilitation and medical *** accomplishing accurate control of the PAM is comparatively complicated due to time-varying behavior,elasticity and ambiguous characteristics,a high performance and efficient control approach should be *** of the mentioned challenges,limited course length is another predicament with the PAM *** this regard,this paper proposes a new hybrid dynamic neural network(DNN)and proportional integral derivative(PID)controller for the position of the *** order to enhance the proficiency of the controller,the problem under study is designed in the form of an optimization *** the potential of particle swarm optimization,it has been applied to optimally tune the PID-DNN *** verify the performance of the proposed controller,it has been implemented on a real-time system and compared to a conventional sliding mode *** and experimental results show the effectiveness of the proposed controller in tracking the reference signals in the entire course of the PAM.

关键词： Dynamic neural network(DNN)control hybrid control pneumatic muscle particle swarm optimization sliding mode control

Phytochemical investigation of medicinally important plants of the Pothohar region of Pakistan

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Journal of Traditional Chinese Medicine 2020年第5期40卷 883-890页

作者： Amna Rabab Sobia Kanwal Tariq mahmood Department of Plant Sciences Quaid-i-Azam UniversityIslamabad 45320Pakistan Department of Zoology University of GujratSub-Campus Rawalpindi 46000Pakistan

OBJECTIVE:To report the phytochemical composition(flavonoids,phenolics,saponins,tannins,and terpenoids)and biological activities(antioxidant,phytotoxic,cytotoxic,antifungal activities)of medicinally important plants of Pothohar ***:In the current study various qualitative and quantitative phytochemical tests were conducted to investigate the phytochemical composition of plant extracts prepared in benzene,chloroform and *** same extracts were further utilized in different biological activities i.e.,antioxidant[total antioxidant capacity,total reducing power,and 2,2-diphenyl-1-picrylhydrazyl(DPPH)scavenging assay],phytotoxicity(Radish seed bioassay),brine shrimp cytotoxicity and antifungal activities(against four pathogenic fungal strains).RESULTS:Phytochemical analysis indicate flavonoids,phenolics,saponins,tannins and terpenoids were present in almost all plants however,maximum amount of total phenolic and flavonoid contents was reported in of Malva parviflora and Lepidium *** of Malva parviflora and Lepidium pinnatifidum also depicted the superlative antioxidant activity(total antioxidant capacity,total reducing power,and DPPH scavenging activity).Maximum fungal growth inhibition was demonstrated by extracts of Centaurea calcitropa,Vicia sativa and Malva *** maximum cytotoxicity was shown by the extracts of Centaurea ***,for phytotoxicity assay the highest allelopathic potential was exhibited by extracts of Lepidium *** prejudiced results;the best results were obtained by Methanol followed by Chloroform and ***:Centaurea calcitropa,Vicia sativa,Malva parviflora and Lepidium pinnatifidum are most promising medicinal plants of Pothohar region for future studies.

关键词： Centaurea Malva Cytotoxins Antifungal agents Phytotoxicity Pothohar region

Exact solutions for the flow of second grade fluid in annulus between torsionally oscillating cylinders

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Acta Mechanica Sinica 2011年第2期27卷 222-227页

作者： Amir mahmood Saima Parveen Najeeb Alam Khan Department of Mathematics COMSATS Institute of Information Technology Lahore Pakistan Abdus Salam School of Mathematical Sciences Lahore Pakistan Department of Mathematics University of Karachi Karachi-75270 Pakistan

The velocity field and the associated shear stress corresponding to the torsional oscillatory flow of a second grade fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. At time t = 0, the fluid and both the cylinders are at rest and at t = 0 ＋ , cylinders suddenly begin to oscillate around their common axis in a simple harmonic way having angular frequencies ω 1 and ω 2 . The obtained solutions satisfy the governing differential equation and all imposed initial and boundary conditions. The solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for Newtonian fluid are also obtained as limiting cases of our general solutions.

关键词： Second grade fluid · Velocity field · Shear stress · Longitudinal oscillatory flow · Laplace and Hankel transforms

Characterization of porous Ti-bioglass composite produced by mechanical milling and space holder sintering

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Rare Metals 2015年第9期34卷 638-644页

作者： Saeed Riahi Mohammad Rajabi Sayed mahmood Rabiee Department of Mechanical Engineering Babol Noshirvani University of Technology

In this study, porous titanium-10 wt% bioglass(BG) composites were fabricated by the process of combining mechanical alloying with space holder sintering. The pore morphology and phase constituents of the milled powders and porous compacts were characterized by scanning electron microscopy(SEM), X-ray diffractometry(XRD), and Fourier transform infrared spectroscopy(FT-IR). The mechanical properties were determined by running compression test. The porosity of the sintered samples shows a downward trend with the increase of milling time. As the porosity increases, both the compressive strength and elastic modulus decrease. The results illustrate that the fabricated porous compacts with high porosity and suitable mechanical properties have the potential application in bone tissue engineering.

关键词： Titanium Bioglass Porous material Mechanical milli

Daily, monthly and annual thermal performance of a linear Fresnel reflector to drive an organic Rankine-cycle system

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Clean Energy 2021年第4期5卷 673-689页

作者： Hassan mahmood Khaled Hossin Mechanical and Construction Engineering University of NorthumbriaNewcastle upon TyneUK Mechanical and Industrial Engineering Department American University of Ras Al KhaimahRas Al KhaimahUnited Arab Emirates Mechanical Engineering Department University of BenghaziBenghaziLibya

The organic Rankine cycle(ORC)coupled with a linear Fresnel reflector(LFR)utilizes a low-grade heat *** article presents the study of a small-scale LFR-ORC power-generation plant under the climatic conditions of Almatret,*** mathematical modelling is performed using thermodynamic equations and simulations are conducted to evaluate the optical performance of the LFR system and thermal performance of the ORC ***-62 is used as a heat-transfer fluid(HTF)in the solar field,whereas NOVEC^(TM) 649 is used as the working fluid in the ORC power *** LFR is integrated with a thermal-storage unit based on a two-tank system and stores the solar thermal energy via a heat *** thermal-energy output of the receiver tube of the LFR system is 108 kW and thermal losses are 7.872 kW during the peak time operation of a day at 1:00 *** mechanical power output of the ORC turbine is 7.296 kW using the specific design conditions and the two-tank thermal-storage system adds 4 operation hours to the power plant after sunset.

关键词： solar energy linear Fresnel reflector energy storage organic Rankine cycle

SI Engine Fueled with Gasoline, CNG and CNG-HHO Blend: Comparative Evaluation of Performance, Emission and Lubrication Oil Deterioration

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Journal of Thermal Science 2021年第4期30卷 1199-1211页

作者： USMAN Muhammad HAYAT Nasir BHUTTA Muhammad mahmood Aslam Department of Mechanical Engineering University of Engineering and TechnologyLahore 54890Pakistan

Hydroxy gas (HHO) is one of the potential alternative fuels for spark ignition (SI) engine,notably due to simultaneous increase in engine performance and reduction in exhaust ***,impact of HHO gas on lubrication oil for longer periods of engine operation has not yet been *** study focuses on investigation of the effect of gasoline,CNG and CNG-HHO blend on lubrication oil deterioration along with engine performance and emissions in SI *** unit produces HHO gas at 4.72 L/min by using 6 g/L of KOH in the aqueous *** was supplied to the test engine at a pressure of 0.11 MPa using an electronically controlled solenoid *** tests were carried out at different speeds at 80%open throttle condition and various performance parameters such as brake power (BP),brake specific fuel consumption(BSFC),brake thermal efficiency (BTE),exhaust gas temperature and exhaust emissions (HC,CO_(2),CO and NO_(x))were *** addition,various lubrication oil samples were extracted over 120 h of engine running while topping for drain out volume and samples were analyzed as per ASTM ***-HHO blend exhibited better performance i.e.,15.4%increase in average BP in comparison to CNG,however,15.1%decrease was observed when compared to ***-HHO outperformed gasoline and CNG in the case of HC,CO_(2),CO and brake specific fuel consumption (31.1%decrease in comparison to gasoline).On the other hand,CNG-HHO produced higher average NO_(x) (12.9%) when compared to CNG ***,lubrication oil condition(kinematic viscosity,water contents,flash point and total base number (TBN)),wear debris (Iron (Fe),Aluminum(Al),Copper (Cu),Chromium (Cr)) and additives depletion (Zinc (Zn),Calcium (Ca)) presented a significant degradation in the case of CNG-HHO blend as compared to gasoline and *** oil analyses illustrated 19.6%,12.8%and 14.2%decrease in average viscosity,flash point and TBN for CNG-HHO blend ***,

关键词： spark ignition engine compressed natural gas hydrogen lubrication oil deterioration emission

Big Data Analytics in Telecommunications: Literature Review and Architecture Recommendations

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IEEE/CAA Journal of Automatica Sinica 2020年第1期7卷 18-38页

作者： Hira Zahid Tariq mahmood Ahsan Morshed Timos Sellis Faculty of Computer Science Institute of Business AdministrationKarachi 75270Pakistan School of Engineering and Technology CQUniversityMelbourne Victoria 3000Australia University of Technology Hawthorn VIC 3122Australia

This paper focuses on facilitating state-of-the-art applications of big data analytics(BDA) architectures and infrastructures to telecommunications(telecom) industrial *** companies are dealing with terabytes to petabytes of data on a daily basis. Io T applications in telecom are further contributing to this data deluge. Recent advances in BDA have exposed new opportunities to get actionable insights from telecom big data. These benefits and the fast-changing BDA technology landscape make it important to investigate existing BDA applications to telecom sector. For this, we initially determine published research on BDA applications to telecom through a systematic literature review through which we filter 38 articles and categorize them in frameworks, use cases, literature reviews, white papers and experimental validations. We also discuss the benefits and challenges mentioned in these articles. We find that experiments are all proof of concepts(POC) on a severely limited BDA technology stack(as compared to the available technology stack), i.e.,we did not find any work focusing on full-fledged BDA implementation in an operational telecom environment. To facilitate these applications at research-level, we propose a state-of-the-art lambda architecture for BDA pipeline implementation(called Lambda Tel) based completely on open source BDA technologies and the standard Python language, along with relevant *** discovered only one research paper which presented a relatively-limited lambda architecture using the proprietary AWS cloud infrastructure. We believe Lambda Tel presents a clear roadmap for telecom industry practitioners to implement and enhance BDA applications in their enterprises.

关键词： Big data analytics BDA pipeline BDA technology stack lambda architecture python systematic literature review telecommunications

CHAIN CONDITIONS FOR C＊-ALGEBRAS COMING FROM HILBERT C＊-MODULES

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Acta Mathematica Scientia 2018年第4期38卷 1163-1173页

作者： mahmood POURGHOLAMHOSSEIN Mohammad ROUZBEHANI Massoud AMINI Department of Mathematics Faculty of Sciences University of Qom Qom Iran Department of Mathematics Faculty of Mathematical Sciences Tarbiat Modares University 14115-134 Tehran Iran

In this paper we define and study chain conditions for Hilbert C＊-modules through their C＊-algebras of compact operators and discuss their perseverance under Morita equivalence and tensor products. We show that these chain conditions are passed from the C＊-algebra to its Hilbert module under certain conditions. We also study chain conditions for Hilbert modules coming from inclusion of C＊-algebra with a faithful conditional expectation.

关键词： Hilbert C*-module Noetherian and Artinian C*-algebras purely infinite C*-algebras Morita equivalence