检索结果-南通市图书馆

Chinese Journal of Chemical Engineering 2019年第5期27卷 1021-1029页

作者： Mohammad Reza Aghajanzadeh Mohammad sharifi Department of Petroleum Engineering Amirkabir University of Technology

In this study, the performance of stable nanofluid containing SiO2 nanoparticles dispersed and stabilized in high salinity brine for asphaltene inhibition in dynamic condition is evaluated. In the first stage of this work, the stability of silica nanoparticles in different range of water salinity(0–100000 mg·L-1) is investigated. Next, stable nanofluid containing highest salinity is selected as asphaltene inhibitor agent to inject into the damaged core sample. The estimated values of oil recovery for base case, after damage process and after inhibition of asphaltene precipitation using nanofluid are 51.6%, 36.1% and 46.7%, respectively. The results showed the reduction in core damage after using nanofluid. In addition, the relative permeability curves are plotted for the base case, after damage process and also after inhibition of asphaltene precipitation using nanofluid. Comparison of relative permeability curves shows, relative permeability of oil phase decreased after damage process as compared with the base case. But after using nanofluid the oil relative permeability curve has shifted to the right and effective permeability of oil phase has been improved.

关键词： Formation damage Enhanced oil recovery Salinity Asphaltene Core flooding Nano particles

Airborne GNSS-Receiver Threat Detection in No-Fading Environments

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2022年第6期31卷 613-620页

作者： Omid sharifi-Tehrani Department of Electrical and Communication Engineering Imam Hussein Comprehensive UniversityTehranIran.

Jamming and spoofing detection of global navigation satellite systems(GNSS)is of great *** and military aerial platforms use GNSS as main navigation systems and these systems are main target of threat *** this paper a simple method based on different empirical probability density functions of successive received signal powers and goodness of fit tech-nique is proposed for airborne platforms such as unmanned aerial vehicle(UAV),in no fading *** two different paths between UAV-satellite and UAV-threat,experience different empirical probability density functions which can be used to distinguish between authentic and threat *** results including detection and false alarm probabilities show good perfor-mance of proposed method as well as low computational burden.

关键词： detection global navigation satellite systems(GNSS) jamming spoofing unmanned aerial vehicle

Cloud service selection using cloud service brokers: approaches and challenges

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2019年第3期13卷 599-617页

作者： Meysam VAKILI Neda JAHANGIRI Mohsen sharifi Department of Computer Engineering University of Science and Culture Tehran 14619-68151 Iran School of Computer Engineering Iran University of Science and Technology Tehran 16846-13114 Iran

Cloud computing users are faced with a wide variety of services to choose from. Consequently, a number of cloud service brokers (CSBs) have emerged to help users in their service selection process. This paper reviews the recent approaches that have been introduced and used for cloud service brokerage and discusses their challenges accordingly. We propose a set of attributes for a CSB to be considered effective. DifFerent CSBs' approaches are classified as either single service or multiple service models. The CSBs are then assessed, analyzed, and compared with respect to the proposed set of attributes. Based on our studies, CSBs with multiple service models that support more of the proposed effective CSB attributes have wider application in cloud computing environments.

关键词： cloud service broker (CSB) cloud service selection cloud computing quality of service (QoS)

New dynamic permeability upscaling method for flow simulation under depletion drive and no-crossflow conditions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2013年第2期10卷 233-241页

作者： Mohammad sharifi Mohan Kelkar McDougall School of Petroleum Engineering The University of Tulsa800 South Tucker DriveTulsaOklahoma74104United States

The main purpose of upscaling in reservoir simulation is to capture the dynamic behavior of fine scale models at the coarse scale. Traditional static or dynamic methods use assumptions about the boundary conditions to determine the upscaled properties, in this paper, we show that the upscaled properties are strongly dependent on the flow process observed at the fine scale. We use a simple no- crossflow depletion drive process and demonstrate that an upscaled property is not a constant value. Instead, if the goal is to match the performance of the fine scale model, the upscaled permeability changes with time. We provide an analytical solution to determine the upscaled permeability and present the value of upscaled permeability under limiting conditions. Our equation suggests that it is possible that upscaled value can fall outside the range of fine scale values under certain conditions. We show that for pseudo steady state flow, using common averaging methods like arithmetic or even geometric averaging methods can lead to optimistic results. We also show that the no-crossflow solution is significantly different than crossflow solution at late times. We validate our method by comparing the results of the method with flow simulation results in two and multi-layered models.

关键词： Upscaling permeability reservoir simulation no-crossflow depletion drive

A review of fluid displacement mechanisms in surfactant-based chemical enhanced oil recovery processes:Analyses of key influencing factors

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第3期19卷 1211-1235页

作者： Ahmed Bashir Amin sharifi Haddad Roozbeh Rafati School of Engineering Kings CollegeUniversity of AberdeenAB243UEUK

Surfactant-based oil recovery processes are employed to lower the interfacial tension in immiscible displacement processes,change the wettability of rock to a more water-wet system and emulsify the oil to displace it in subsurface porous ***,these phenomena can reduce the capillary pressure and enhance spontaneous *** key factors affecting such immiscible displacement process are temperature,salinity and p H of the fluids,surfactant concentration and ***,before any surfactant flooding process is applied,extensive studies of fluid-fluid and rock-fluid interactions are *** use of other chemicals along with surfactants in chemical enhanced oil recovery(c EOR)processes have been widely considered to exploit the synergy of individual chemicals and complement the weakness arises from each of them during immiscible displacement of fluids in porous ***,such combinations of chemicals lead to alkaline-surfactant(AS),surfactantpolymer(SP),alkaline-surfactant-polymer(ASP),and nanoparticle-surfactant(NS)flooding processes,among *** this review study,we categorised the role and displacement mechanisms of surfactants and discussed the key factors to be considered for analysing the fluid displacement in porous media.

关键词： Alkaline surfactant(AS)flooding Alkaline-surfactant-polymer(ASP)flooding Enhanced oil recovery(EOR) Interfacial tension(IFT) Nanoparticle-surfactant(NS)flooding Surfactant adsorption Surfactant-polymer(SP)flooding Wettability alteration

Coupled and splitting bedload sediment transport models based on a modified flux-wave approach

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2021年第1期36卷 38-49页

作者： Hossein Mahdizadeh Soroosh sharifi Department of Civil Engineering University of Birjand Department of Civil Engineering University of Birmingham

Numerical modeling of free-surface flow over a mobile bed with predominantly bedload sediment transport can be done by solving the shallow water and Exner equations using coupled and splitting *** coupled method uses a coupling of the governing equations at the same time step leading to a non-conservative *** splitting method solves the Exner and the shallow water equations in a separate manner,and is only capable of modeling weak free-surface and bedload *** the current study,an extended version of a Godunov-type wave propagation algorithm is presented for modeling of morphodynamic systems using both coupled and splitting *** the introduced coupled method the entire morphodynamic system is solved in the form of a conservation *** the splitting technique,a new wave Riemann decomposition is defined which enables the scheme to be utilized for mild and strong *** consider the bedload sediment discharge within the Exner equation,the Smart and Meyer-Peter & Miiller formulae are *** was found that the coupled solution gives accurate predictions for all investigated flow regimes including pro pagation over a dry-state using a Courant-Friedrichs-Lewy(CFL) number equal to ***,the splitting method was able to model all flow regimes with a lower CFL number of 0.3.

关键词： Bedload sediment transport Coupled solution Flux-wave method Shallow water equations Splitting technique Wave propagation algorithm

Synthesis of highly selective and stable mesoporous Ni-Ce/SAPO-34 nanocatalyst for methanol-to-olefin reaction:Role of polar aprotic N,N-dimethylformamide solvent

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2018年第5期16卷 113-122页

作者： Hossein Akhoundzadeh Majid Taghizadeh Hassan sharifi Pajaie Chemical Engineering Department Bahai Noshirvani University of TechnologyP.O.Box 484Babo***Iran Wood and Paper Science Department Faculty of Natural ResourcesSariAgricultural Sciences and Natural Resource UniversityP.O.Box 737SariIran

A series of mesoporous nanocrystalline silicoaluminophosphate (SAPO)zeolites (SAPO-34)were synthesized via an ultrasonic and microwave-assisted hydrothermal method in the presence of [3- (trimethoxysilyl)propyl]octadecyldimethylammonium chloride and cetyltrimethylammonium bromide surfactants as soft *** and cerium were then doped on SAPO-34using incorporation and impregnation methods,and all the catalysts were applied to the methanol-to-olefin (MTO)reaction. The catalysts were characterized using X-ray diffraction,field-emission scanning electron microcopy, inductively coupled plasma-atomic emission spectroscopy,transmission electron microscopy,Fourier- transform infrared spectroscopy,Brunauer-Emmett-Teller analysis,NH3temperature-programmed desorption analysis,and thermogravimetric *** the impregnation method,the effect of using protic or aprotic solvents as impregnation media on the physico-chemical properties of the metal-based SAPO-34was *** and N,N-dimethylformamide (DMF)were employed as the protic and aprotic solvents,*** catalyst prepared using the aprotic DMF solvent exhibited higher dispersion and lower aggregation of metal species compared with that prepared using the protic water ***,the sample synthesized using the incorporation method exhibited good catalytic performance;however,the Ni-Ce[SAPO-34 sample prepared using the impregnation method and aprotic DMF solvent exhibited superior catalytic performance in the MTO reaction.

关键词： Ni-Ce/SAPO-34 MTO reaction Impregnation Aprotic solvent Protic solvent

Shape factor for regular and irregular matrix blocks in fractured porous media

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2020年第1期17卷 136-152页

作者： Peyman Rostami Mohammad sharifi Morteza Dejam Department of Petroleum Engineering Amirkabir University of Technology(Polytechnic of Tehran)Hafez AvenueP.O.Box 15875-4413TehranIran Department of Petroleum Engineering College of Engineering and Applied ScienceUniversity of Wyoming1000 E.University AvenueLaramieWY 82071-2000USA

Describing matrix–fracture interaction is one of the most important factors for modeling natural fractured reservoirs.A common approach for simulation of naturally fractured reservoirs is dual-porosity modeling where the degree of communication between the low-permeability medium(matrix)and high-permeability medium(fracture)is usually determined by a transfer *** of the proposed matrix–fracture functions depend on the geometry of the matrix and fractures that are lumped to a factor called shape ***,there is no unique solution for calculating the shape factor even for symmetric *** fine-scale modeling is a tool for calculating the shape factor and validating the current solutions in the *** this study,the shape factor is calculated based on the numerical simulation of fine-grid simulations for single-phase flow using finite element *** the best of the author’s knowledge,this is the first study to calculate the shape factors for multidimensional irregular bodies in a systematic *** models were used,and shape factors were calculated for both transient and pseudo-steady-state(PSS)cases,although in some cases they were not clarified and assumptions were not *** boundary condition dependency of the shape factor was also investigated,and the obtained results were compared with the results of other *** show that some of the most popular formulas cannot capture the exact physics of matrix–fracture *** obtained results also show that both PSS and transient approaches for describing matrix–fracture transfer lead to constant shape factors that are not unique and depend on the fracture pressure(boundary condition)and how it changes with time.

关键词： Fractured reservoirs Shape factor Matrix–fracture boundary conditions Computational fluid dynamic(CFD)

A new post-coding approach for PAPR reduction in DC-biased optical OFDM systems

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2019年第4期15卷 302-305页

作者： Abbas Ali sharifi Department of Electrical Engineering University of Bonab

The high peak-to-average power ratio(PAPR) is one of the main drawbacks in orthogonal frequency division multiplexing(OFDM) communication systems, which also exists in the optical OFDM(O-OFDM) systems. In this letter, a new approach based on the discrete Hartley transform(DHT) post-coding technique is proposed to reduce PAPR of an O-OFDM signal in visible light communication systems. The proposed method is compared with Walsh-Hadamard transform(WHT) and discrete cosine transform(DCT) techniques in terms of PAPR reduction and bit error rate(BER)performance. Experimental results indicate that the proposed DHT post-coding method remarkably reduces the PAPR of an OFDM signal for optical intensity modulated direct detection systems without any corruption in the BER performance.

关键词： peak-to-average power ratio(PAPR) optical OFDM(O-OFDM) discrete Hartley transform(DHT)

Street network patterns for mitigating urban heat islands in arid climates

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2023年第1期16卷 3145-3161页

作者： Kimia Chenary Ali Soltani Ayyoob sharifi Department of Architecture and Urban Planning Bojnourd UniversityBojnourdIran Injury Studies FHMRIBedford ParkAustralia UniSA Business University of South AustraliaAdelaideAustralia Department of Urban Planning Shiraz UniversityShirazIran The IDEC Institute and Network for Education and Research on Peace and Sustainability(NERPS) Hiroshima UniversityHigashihiroshimaJapan

This study explores the impact of street pattern measurements on urban heat islands(UHI)in the arid climate of Mashhad,*** Landsat-8 top-of-the-atmosphere(TOA)brightness images from 2013 to 2021,average values of normalized difference vegetation index(NDvI)and land surface temperature(LST)were *** pattern measurements,including closeness-centrality,straightness,and street orientation,were employed to analyse the patterns in each *** results indicated that districts with higher straightness and lower closeness-centrality exhibit,cooler surface *** correlations were observed between LST and NDVl,straightness,and local *** research highlighted the importance of considering street network measurements in long-term urban planning and design to mitigate the UHI effect in arid regions.A moderate grid street pattern with a reasonable distribution of green spaces throughout the region is suggested to reduce surface temperatures *** pattern indexes,such as straightness and local closeness-centrality,are identified as significant factors in urban design to mitigate *** findings have implications for urban planners,who can use this information to create street network patterns with lower UHI effects by reducing local closeness-centrality and increasing straightness.

关键词： Urban heat island Urban form Street network pattern Green space distribution