检索结果-南通市图书馆

Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

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 2019年第6期16卷 1387-1402页

作者： sajjad Mahmoudi Arezou Jafari soheila Javadian Department of Petroleum Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran Department of Physical Chemistry Faculty of Basic ScienceTarbiat Modares UniversityP.O.Box 14115-175TehranIran

Recently,nanoparticles have been used along with surfactants for enhancing oil *** the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions,some effective parameters and mechanisms involved in the oil recovery have not yet been ***,the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work,and the optimal concentrations of both siO2 nanoparticle and surfactant(sodium dodecyl sulfate)have been determined by the Central Composite Design *** addition,the simultaneous effects of parameters and their interactions have been *** of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution *** surfactant makes the solution more stable if used in appropriate concentrations below the *** to the micromodel flooding results,the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant ***,in floodings with higher porous medium temperature,the oil viscosity reduction is considerable,and more oil is *** addition,the surfactant concentration plays a more effective role in reservoirs with higher *** other words,at a surfactant concentration of 250 ppm,the ultimate oil recovery is improved about 20%with a temperature increase of 20°***,when the surfactant concentration is equal to 750 ppm,the temperature increase enhances the ultimate oil recovery by only about 7%.Finally,the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm,*** is worthy to note that obtained results are validated by the confirmation test.

关键词： Enhanced heavy oil recovery Nanoparticle surfactant Temperature high salinity brine stability Micromodel Experimental design

spaceborne and ground-based sensor collaboration:Advancing resident space objects’orbit determination for space sustainability

在线全文

学校读者我要写书评

暂无评论

Astrodynamics 2024年第3期8卷 325-347页

作者： Niki sajjad Mehran Mirshams Andreas Makoto hein space Research Laboratory Department of Aerospace EngineeringK.N.Toosi University of TechnologyTehran16569-83911Iran Interdisciplinary Centre for security Reliability and Trust(SnT)University of LuxembourgLuxembourg1855Luxembourg

The limited space around the Earth is getting cluttered with leftover fragments from old missions,creating a real *** more satellites are launched,even debris pieces as small as 5 mm must be tracked to avoid ***,it is an arduous and challenging task in *** paper presents a technical exploration of ground-based and in-orbit space debris tracking and orbit determination *** highlights the challenges faced during on-ground and in-orbit demonstrations,identifies current gaps,and proposes solutions following technological advancements,such as low-power pose estimation *** to the numerous atmospheric barriers to ground-based sensors,this study emphasizes the significance of spaceborne sensors for precise orbit determination,complemented by advanced data processing algorithms and collaborative *** ultimate goal is to create a comprehensive catalog of resident space objects(RsO)around the Earth and promote space environment *** exploring different methods and finding innovative solutions,this study contributes to the protection of space for future exploration and the creation of a more transparent and precise map of orbital objects.

关键词： resident space objects(RsO) space debris orbit determination tracking ground-based sensors spaceborne sensors

Algorithms for handoff Minimization in Wireless Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computer science & Technology 2019年第4期34卷 887-900页

作者： Mansoor Davoodi Esmaeil Delfaraz sajjad Ghobadi Mahtab Masoori Institute for Advanced studies in Basic sciences Zanjan 45137-66731Iran Gran sasso science Institute L'Aquila 67100Italy

This study focuses on the problem of handoff minimization for a set of users moving in a wireless *** problem is analyzed by considering two cases for the user's movement under access point capacity constraints:1)all users move together,and 2)each user can have their chosen path within the *** the first case,we propose an optimal competitive ratio algorithm for the ***,in the second case,having the connectivity assumption,that is,"if a user is connected to an access point so long that the received signal strength of the access point is not less than a specified threshold,the user should continue his/her connection",we prove that no approach can reduce the number of unnecessary handoffs in an offline ***,without connectivity assumption,we present an optimal deterministic algorithm with the competitive ratio of n?for this problem under online setting,where n is the number of users and?is the maximum number of access points which cover any single point in the ***,we prove that the randomized version of the algorithm achieves an expected competitive ratio of O(log△).

关键词： competitive ratio handoff minimization offline algorithm online algorithm wireless network

Designing Pair of Nonlinear Components of a Block Cipher over Gaussian Integers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第6期75卷 5287-5305页

作者： Muhammad sajjad Tariq shah Robinson Julian serna Department of Mathematics Quaid-I-Azam UniversityIslamabad45320Pakistan Escuela de Matemáticas y Estadística Universidad Pedagógica y Tecnológica de ColombiaTunja150003Columbia

In block ciphers,the nonlinear components,also known as sub-stitution boxes(s-boxes),are used with the purpose of inducing confusion in *** the last decade,most of the work on designing s-boxes over the points of elliptic curves has been *** main purpose of these studies is to hide data and improve the security levels of crypto *** this work,we design pair of nonlinear components of a block cipher over the residue class of Gaussian integers(GI).The fascinating features of this structure provide s-boxes pair at a time by fixing three *** the prime field dependent on the Elliptic curve(EC)provides one s-box at a time by fixing three parameters a,b,and *** newly designed pair of s-boxes are assessed by various tests like nonlinearity,bit independence criterion,strict avalanche criterion,linear approximation probability,and differential approximation probability.

关键词： Gaussian integers residue class of gaussian integers block cipher s-boxes analysis of s-boxes

On new classes of strongly Janowski type functions of complex order

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2023年第1期38卷 89-99页

作者： Khalil Ahmad Khudija Bibi M.sajjad shabbir Department of Mathematics Air UniversityPAF-ComplexSector E-9IslamabadPakistan Department of Mathematics Faculty of Basic and AppliedInternational Islamic University IslamabadPakistan Department of Mathematics University of Poonch RawalakotAzad Kashmir 12350Pakistan

We investigate some new subclasses of analytic functions of Janowski type of complex *** also study inclusion properties,distortion theorems,coefficient bounds and radius of convexity of the ***,analytic properties of these classes under certain integral operator are also *** findings are more comprehensive than the existing results in the literature.

关键词： subordination Janowski function starlike function convex function complex order

Elemental characterization of black shales of Khyber Pakthunkhawa (KPK) region of Pakistan using AAs

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2013年第3期32卷 248-251页

作者： Abdul Aziz Muhammad sajjad Bashir Mohammad Central Analytical Facility Division Pakistan Institute of Nuclear Science and Technology Department of Construction Environment Engineering University of Science and Technology

Black shale samples were collected from Chimiari Khyber Pakthunkhawa region of Pakistan and were analyzed for elemental compositions. Atomic Absorption spectrophotometry (AAs) was utilized for the determination of elements in the digested solutions. The analysis of black shale was performed precisely with relative standard deviation (RsD) lower than 2%. Results showed that the samples contained high concentrations of Ca (11.98 %), Al (7.09%), Fe (3.03%), Mg (0.59%) and Ti (0.58%).

关键词：原子吸收光谱法黑色页岩巴基斯坦元素组成表征相对标准偏差元素测定精确分析

PdCu alloy anchored defective titania for photocatalytic conversion of carbon dioxide into methane with 100% selectivity

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第4期91卷 254-265页

作者： Lina Zhang sajjad hussain Qiuye Li Jianjun Yang National&Local Joint Engineering Research Center for Applied Technology of hybrid Nanomaterials Henan UniversityKaifeng 475004HenanChina

The photoreduction of CO_(2)into Ch_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global ***,the absence of the active sites that is responsible for the adsorption and activation of CO_(2)and the generation of CO and h2via side reactions often lead to poor efficiency and low selectivity of the ***,Cu,Pd,and PdCu metal clusters cocatalyst-anchored defective TiO_(2)nanotubes(Cu/TiO_(2)-sBO,Pd/TiO_(2)-sBO,and Pd1Cu1/TiO_(2)-sBO)were designed via a simple solution impregnation reduction and applied for photocatalytic conversion of CO_(2)to Ch_(4).The Pd1Cu1/TiO_(2)-sBO photocatalyst exhibits excellent catalytic performance among the other catalysts for photoreduction of CO_(2)into Ch_(4).More interestingly,the product selectivity of Ch_(4)reaches up to 100%with a rate of 25μmol g^(-1)h^(-1).In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs)and density functional theory(DFT)simulations indicate that the main reasons for the high selectivity of Ch_(4)are attributed to the PdCu alloy and oxygen vacancies,which jointly enhance the photoinduced carrier separation and lower energy barriers of key ***,due to the tunable d-band center of the Cu site in the PdCu alloy,the generated intermediates can be well prevented from poisoning and promoted to participate in further ***,the current study will provide insight into the development of new,highly selective photocatalysts for the visible light-catalytic reduction of CO_(2)into Ch_(4).

关键词： PdCu alloy Defective TiO_(2) Photoreduction of CO_(2) Photocatalytic mechanism

Long-range precipitation forecasts using paleoclimate reconstructions in the western United states

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2016年第4期13卷 614-632页

作者： Christopher Allen CARRIER Ajay KALRA sajjad AhMAD Department of Civil and Environmental Engineering University of NevadaLas Vegas4505 S.Maryland ParkwayLas VegasIVV89154-4015USA Development Review Division Clark County Public Works500 S.Grand Central ParkwayLas VegasNV 89155USA Department of Civil and Environmental Engineering Southern Illinois University1230 Lincoln DriveCarbondaleIL 62901-6603USA

Long-range precipitation forecasts are useful when managing water *** oscillations have been shown to influence *** to a longer cycle of some of the oscillations,a short instrumental record is a limitation in using them for long-range precipitation *** influence of oscillations over precipitation is observable within paleoclimate reconstructions;however,there have been no attempts to utilize these reconstructions in precipitation forecasting.A data-driven model,Kstar,is used for obtaining long-range precipitation forecasts by extending the period of record through the use of reconstructions of *** is a nearest neighbor algorithm with an entropy-based distance ***-atmospheric oscillation reconstructions include the El Nino-southern Oscillation(ENsO),the Pacific Decadal Oscillation(PDO),the North Atlantic Oscillation(NAO),and the Atlantic Multi-decadal Oscillation(AMO).Precipitation is forecasted for 20 climate divisions in the western United states.A 10-year moving average is applied to aid in the identification of oscillation phases.A lead time approach is used to simulate a one-year forecast,with a 10-fold cross-validation technique to test the *** are used from 1658-1899,while the observed record is used from *** model is evaluated using mean absolute error(MAE),root mean squared error(RMsE),RMsE-observations standard deviation ratio(RsR),Pearson's correlation coefficient(R),Nashsutcliffe coefficient of efficiency(NsE),and linear error in probability space(LEPs) skill score(sK).The role of individual and coupled oscillations is evaluated by dropping oscillations in the *** results indicate 'good' precipitation estimates using the Kstar *** modeling technique is expected to be useful for long-term water resources planning and management.

关键词： Precipitation Oscillations Paleoclimate reconstruction Forecast Kstar

Estimating solubility of supercritical h_2s in ionic liquids through a hybrid LssVM chemical structure model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第3期27卷 620-627页

作者： Alireza Baghban Jafar sasanipour sajjad habibzadeh Zhi'en Zhang Chemical Engineering Department Amirkabir University of Technology Gas Engineering Department Petroleum University of Technology Key Laboratory of Low-grade Energy Utilization Technologies and systems Ministry of Education of China Chongqing University

Development of a predictive tool for h_2s solubility estimation can be very helpful in gas sweetening industry. Experimental databases on h_2 s solubility were rarely available, so as reliable predictive models. Thus, in this study the h_2 s solubility database was established, and then a Least-squares support Vector Machine(LssVM) approach based on the established database is proposed. Group contribution method was also applied to eliminate the model's dependence on experimental data. Accordingly, our proposed LssVM model can predict h_2 s solubility as a function of temperature, pressure, and 15 different chemical structures of Ionic liquids(ILs). Root Mean square Error(RMsE) and coefficient of determination(R^2) are 0.0122 and 0.9941, respectively. Moreover, comparison of our model with other existing models showed its reliability for h_2 s solubility in ILs. This can be very useful for engineers dealing with gas sweetening process in different applications of analysis, simulation, and designation.

关键词： Ionic liquid hydrogen sulfide LssVM Group contribution method