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Quantitative investigation of nanofluid imbibition in tight oil reservoirs based on NMR technique

Petroleum Science 2022年第5期19卷 2185-2198页

作者： Tian-Tian Zhang Zhi-Ping Li Caspar Daniel Adenutsi Yong-Zhou Wei Zhen-Fu Ma Qing You School of Energy Resources China University of GeosciencesBeijing10083China Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering Beijing10083China core and Rock Properties Laboratory Department of Petroleum EngineeringFaculty of Civil and Geo-EngineeringKwame Nkrumah University of Science and TechnologyKumasiGhana Binnan Oil Production Plant Shengli Oilfield CompanySINOPECBinzhou256606ShandongChina Hekou Oil Production Plant Shengli Oilfield CompanySINOPECDongying257200ShandongChina

Nanofluids have been effective chemical additives for enhanced oil recovery(EOR)in tight oil reservoirs due to their special properties.However,oil imbibition recoveries vary for different nanofluids.The oil/water distribution in rocks during imbibition using various nanofluids was less discussed in previous studies.In this study,we systematically examined the imbibition efficiencies of various nanofluids at60℃.Furthermore,the migration of nanofluids and oil distribution in the rock pores were monitored using nuclear magnetic resonance(NMR).The nanofluids were prepared by dispersing silica nanoparticles and five different types of surfactants i.e.,anionic-nonionic,anionic,nonionic,amphoteric and cationic surfactants in deionized(DI)water.Subsequently,interfacial tension(IFT)and contact angle measurements were conducted to reveal the underlying EOR mechanisms of various nanofluids.The experimental results showed that the EOR potential of the different types of nanofluids was in the order anionic-nonionic>anionic>nonionic>amphoteric>cationic>brine.Anionic-nonionic(sodium lauryl ether sulfate(SLES))and anionic(sodium dodecyl sulfonate(SDS))nanofluids exhibited excellent capability of wettability alteration,and increased oil recovery by 27.96%and 23.08%,respectively,compared to brine.The NMR results also showed that mesopores(0.1-1μm)were the dominant developed pores in the rocks,and contributed the most to imbibition efficiency.In addition,the imbibition of nanofluids initially took place in mesopores and micropores before moving into macropores.This study provides fundamental information on the selection of nanofluids for EOR in tight oil reservoirs.The study also improved the understanding of oil/water distribution during the imbibition of the proposed nanofluids.

关键词： Nanofluids Spontaneous imbibition Nuclear magnetic resonance(NMR) Oil migration Tight oil reservoir

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Aggregated structures and their functionalities in hydrogels

Aggregate

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Aggregate 2021年第2期2卷 16-27页

作者： Kunpeng Cui Jian Ping Gong Institute for Chemical Reaction Design and Discovery(WPI-ICReDD) Hokkaido UniversitySapporoJapan Soft Matter GI-core Hokkaido UniversitySapporoJapan faculty of Advanced Life Science Hokkaido UniversitySapporoJapan

Biological soft tissues and hydrogels belong to the same category of soft and wet matter.Both of them are composed of polymer network and a certain amount of water,and permeable to small molecules.Biological tissues possess elaborated structures and exhibit outstanding functionalities.On the other hand,hydrogels are usually amorphous with poor functionality.In recent years,various hydrogels with robust functionalities have been developed by introducing aggregated structures into the gel networks,widely extend their applications in diverse fields,such as soft actuators,biological sensors,and structural biomaterials.Four strategies are usually used to fabricate aggregated structure into hydrogels,including molecular self-assembling,microphase separation,crystallization,and inorganic additives.Different aggregated structures entail the gel very different functionalities.A simple aggregated structure is able to bring multiple functionalities and a combination of mechanical performances of the hydrogels.In this review,we describe the strategies used to construct aggerated structure in hydrogels and discuss about the close relation between the aggregated structure and functionality.We also highlight the role of nonequilibrium aggregated structure in fabricating hydrogels with dynamic memorizing-forgetting behavior and point out the remaining challenges.

关键词： aggregated structure functionality hydrogel

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Predictors of Health-Related Quality of Life in Children with Cyanotic Heart Disease Who Underwent Palliative and Total Repair

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Congenital Heart Disease 2022年第3期17卷 245-267页

作者： Jutarat Tanasansuttiporn Maliwan Oofuvong Wirat Wasinwong Voravit Chittithavorn Pongsanae Duangpakdee Jirayut Jarutach Qistina Yunuswangsa Department of Anesthesiology Faculty of MedicinePrince of Songkla UniversitySongkhla90110Thailand Department of Surgery Faculty of MedicinePrince of Songkla UniversitySongkhla90110Thailand Department of Pediatrics Faculty of MedicinePrince of Songkla UniversitySongkhla90110Thailand

Background:Studies on predictors of health-related quality of life(HRQOL)in pediatric patients with cyanotic heart disease who are waiting for the next stage and those who have undergone total repair are scarce.Therefore,we aimed to identify such predictors in children who received the modified Blalock–Taussig shunt(MBTS)and those who underwent total repair.Methods:In this historical cohort and concurrent follow-up study,data of children who underwent MBTS at the age of 0–3 years between January 2005 and December 2016 at a super-tertiary care hospital in Southern Thailand were obtained.Children who were alive in December 2017 were recruited to evaluate the quality of life at least 1 year after their operation.Between January and December 2018,the“Pediatric Quality of Life Inventory 4.0 Generic core Scales”with both child self-report and parent proxy-report scores were used to examine the HRQOL.Multivariate linear regression analysis was performed to identify independent predictors of HRQOL.Beta-coefficient(β)and 95% confidence intervals(95%CIs)were calculated and considered statistically significant at p<0.05.Results:Among the 380 enrolled children,148 died,122 survived and waited for total repair,and 110 survived after total repair.In the multivariate analysis,chronic lung disease was a common predictor of lower physical and psychosocial HRQOL reported by the parents(β[95%CI]:−0.42[−0.81,−0.03]and−0.49[−0.89,−0.09],respectively).Total repair was a predictor of higher physical HRQOL according to both parents and children(β[95%CI]:0.33[0.09,0.57]and 0.70[0.36,1.03],respectively).A predictor of higher psychosocial HRQOL reported by the parents was younger age during MBTS surgery compared with older age(β[95%CI]:0.012[0.001,0.022]).In the total repair subgroup,undergoing the Fontan procedure(vs.Glenn procedure)was a predictor for lower physical HRQOL reported by the parents(β[95%CI]:−0.82[−1.52,−0.13]).Higher socioeconomic status was a predictor of both physical and psychosocial HRQOL(β[95%CI]:0.018[0.001,0.034]and

关键词： Children modified Blalock–Taussig shunt predictors health-related quality of life total repair

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Surface activity of cancer cells:The fusion of two cell aggregates

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BIOCELL 2023年第1期47卷 15-25页

作者： IVANA PAJIC-LIJAKOVIC MILAN MILIVOJEVIC faculty of Technology and Metallurgy Belgrade UniversityBelgradeSerbia

A key feature that distinguishes cancer cells from all other cells is their capability to spread throughout the body.Although how cancer cells collectively migrate by following molecular rules which influence the state of cell-cell adhesion contacts has been comprehensively formulated,the impact of physical interactions on cell spreading remains less understood.Cumulative effects of physical interactions exist as the interplay between various physical parameters such as(1)tissue surface tension,(2)viscoelasticity caused by collective cell migration,and(3)solid stress accumulated in the cell aggregate core region.This review aims to point out the role of these physical parameters in cancer cell spreading by considering and comparing the rearrangement of various mono-cultured cancer and epithelial model systems such as the fusion of two cell aggregates.While epithelial cells undergo volumetric cell rearrangement driven by the tissue surface tension,which directs cell movement from the surface to the core region of two-aggregate systems,cancer cells rather perform surface cell rearrangement.Cancer cells migrate toward the surface of the two-aggregate system driven by the solid stress while the surface tension is significantly reduced.The solid stress,accumulated in the core region of the two-aggregate system,is capable of suppressing the movement of epithelial cells that can undergo the jamming state transition;however,this stress enhances the movement of cancer cells.We have focused here on the multi-scale rheological modeling approaches that aimed at reproducing and understanding these biological systems.

关键词： Collective cell migration Tissue surface tension Surface activity of cancer cells Viscoelasticity Solid stress The state of cell-cell adhesion contacts

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Speckle filtering of Synthetic Aperture Radar images using filters with object-size-adapted windows

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International Journal of Digital Earth 2018年第7期11卷 703-729页

作者： Sahel Mahdavi Bahram Salehi Cecilia Moloney Weimin Huang Brian Brisco C-core Faculty of Engineering and Applied ScienceMemorial University of NewfoundlandSt John’sNLCanada Department of Electrical Engineering Faculty of Engineering and Applied ScienceMemorial University of NewfoundlandSt.John’sNLCanada Canada Center for Mapping and Earth Observation OttawaONCanada

Speckle degrades the radiometric quality of a Synthetic Aperture Radar(SAR)image.Previous methods for speckle reduction have used a fixedsize window for filtering the entire image.This,however,may not be effective for the entire image,as land covers of different sizes require different filtering windows.In this paper,a novel method is proposed by which each pixel in the image is filtered with a window appropriate for the size of object within it.The real in-phase and the imaginary quadrature components of the SAR images determine the best window size and the pixels in the intensity image are filtered using their own optimal windows.The proposed method is presented for both singleand multi-polarized SAR images,and the results of several common filters that were modified are presented.This approach is applied to two RADARSAT-2 images:one over San Francisco,California,USA and the other over St.John’s,Newfoundland and Labrador,Canada,producing results that were similar to,or outperformed,comparable filters while retaining details and suppressing speckle effectively.While the method was successful for single-look intensity data,it offers great potential for multi-look and amplitude data as well.

关键词： Speckle Synthetic Aperture Radar(SAR) filters adaptive window size

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Energy-Efficient Scheduling Based on Task Migration Policy Using DPM for Homogeneous MPSoCs

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Computers, Materials & Continua 2023年第1期74卷 965-981页

作者： Hamayun Khan Irfan Ud din Arshad Ali Sami Alshmrany Department of Electrical Engineering Faculty of Engineering&Technology Superior University Lahore54000Pakistan Department of Computer Science Faculty of Computer Science&IT Superior University Lahore54000Pakistan faculty of Computer and Information Systems Islamic University of MadinahAl Madinah Al Munawarah42351Saudi Arabia

Increasing the life span and efficiency of Multiprocessor System on Chip(MPSoC)by reducing power and energy utilization has become a critical chip design challenge for multiprocessor systems.With the advancement of technology,the performance management of central processing unit(CPU)is changing.Power densities and thermal effects are quickly increasing in multi-core embedded technologies due to shrinking of chip size.When energy consumption reaches a threshold that creates a delay in complementary metal oxide semiconductor(CMOS)circuits and reduces the speed by 10%–15%because excessive on-chip temperature shortens the chip’s life cycle.In this paper,we address the scheduling&energy utilization problem by introducing and evaluating an optimal energy-aware earliest deadline first scheduling(EA-EDF)based technique formultiprocessor environments with task migration that enhances the performance and efficiency in multiprocessor systemon-chip while lowering energy and power consumption.The selection of core andmigration of tasks prevents the system from reaching itsmaximumenergy utilization while effectively using the dynamic power management(DPM)policy.Increase in the execution of tasks the temperature and utilization factor(u_(i))on-chip increases that dissipate more power.The proposed approach migrates such tasks to the core that produces less heat and consumes less power by distributing the load on other cores to lower the temperature and optimizes the duration of idle and sleep times across multiple CPUs.The performance of the EA-EDF algorithm was evaluated by an extensive set of experiments,where excellent results were reported when compared to other current techniques,the efficacy of the proposed methodology reduces the power and energy consumption by 4.3%–4.7%on a utilization of 6%,36%&46%at 520&624 MHz operating frequency when particularly in comparison to other energy-aware methods for MPSoCs.Tasks are running and accurately scheduled to make an energy-efficient processor by controlling and managing the therm

关键词： Dynamic power management dynamic voltage&frequency scaling dynamic thermal management multiprocessor system on chip complementary metal oxide semiconductor reliability

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An Optimal DPM Based Energy-Aware Task Scheduling for Performance Enhancement in Embedded MPSoC

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Computers, Materials & Continua 2023年第1期74卷 2097-2113页

作者： Hamayun Khan Irfan Ud Din Arshad Ali Mohammad Husain Department of Electrical Engineering Faculty of Engineering&Technology Superior University Lahore54000Pakistan Department of Computer Science Faculty of Computer Science&IT Superior University Lahore54000Pakistan faculty of Computer and Information Systems Islamic University of MadinahAl Madinah Al Munawarah42351Saudi Arabia

Minimizing the energy consumption to increase the life span and performance of multiprocessor system on chip(MPSoC)has become an integral chip design issue for multiprocessor systems.The performance measurement of computational systems is changing with the advancement in technology.Due to shrinking and smaller chip size power densities onchip are increasing rapidly that increasing chip temperature in multi-core embedded technologies.The operating speed of the device decreases when power consumption reaches a threshold that causes a delay in complementary metal oxide semiconductor(CMOS)circuits because high on-chip temperature adversely affects the life span of the chip.In this paper an energy-aware dynamic power management technique based on energy aware earliest deadline first(EA-EDF)scheduling is proposed for improving the performance and reliability by reducing energy and power consumption in the system on chip(SOC).Dynamic power management(DPM)enables MPSOC to reduce power and energy consumption by adopting a suitable core configuration for task migration.Task migration avoids peak temperature values in the multicore system.High utilization factor(ui)on central processing unit(CPU)core consumes more energy and increases the temperature on-chip.Our technique switches the core bymigrating such task to a core that has less temperature and is in a low power state.The proposed EA-EDF scheduling technique migrates load on different cores to attain stability in temperature among multiple cores of the CPU and optimized the duration of the idle and sleep periods to enable the low-temperature core.The effectiveness of the EA-EDF approach reduces the utilization and energy consumption compared to other existing methods and works.The simulation results show the improvement in performance by optimizing 4.8%on u_(i) 9%,16%,23%and 25%at 520 MHz operating frequency as compared to other energy-aware techniques for MPSoCs when the least number of tasks is in running state and can schedule more tasks to make an energy-efficient

关键词： Dynamic power management dynamic voltage&frequency scaling dynamic thermal management multiprocessor system on chip complementary metal oxide semiconductor reliability

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Enhancing Task Assignment in Crowdsensing Systems Based on Sensing Intervals and Location

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Computers, Materials & Continua 2022年第6期71卷 5619-5638页

作者： Rasha Sleem Nagham Mekky Shaker El-Sappagh Louai Alarabi Noha AHikal Mohammed Elmogy faculty of Computers and Information Mansoura UniversityMansoura35516Egypt faculty of Computers and Artificial Intelligence Benha UniversityBanha13518Egypt faculty of Computer Science and Engineering Galala UniversitySuez435611Egypt College of Computer and Information Systems Umm Al-Qura UniversityMecca715Saudi Arabia

The popularity of mobile devices with sensors is captivating the attention of researchers to modern techniques,such as the internet of things(IoT)and mobile crowdsensing(MCS).The core concept behind MCS is to use the power of mobile sensors to accomplish a difficult task collaboratively,with each mobile user completing much simpler micro-tasks.This paper discusses the task assignment problem in mobile crowdsensing,which is dependent on sensing time and path planning with the constraints of participant travel distance budgets and sensing time intervals.The goal is to minimize aggregate sensing time for mobile users,which reduces energy consumption to encourage more participants to engage in sensing activities and maximize total task quality.This paper introduces a two-phase task assignment framework called location time-based algorithm(LTBA).LTBA is a framework that enhances task assignment in MCS,whereas assigning tasks requires overlapping time intervals between tasks and mobile users’tasks and the location of tasks and mobile users’paths.The process of assigning the nearest task to the mobile user’s current path depends on the ant colony optimization algorithm(ACO)and Euclidean distance.LTBA combines two algorithms:(1)greedy online allocation algorithm and(2)bio-inspired traveldistance-balance-based algorithm(B-DBA).The greedy algorithm was sensing time interval-based and worked on reducing the overall sensing time of the mobile user.B-DBA was location-based and worked on maximizing total task quality.The results demonstrate that the average task quality is 0.8158,0.7093,and 0.7733 for LTBA,B-DBA,and greedy,respectively.The sensing time was reduced to 644,1782,and 685 time units for LTBA,B-DBA,and greedy,respectively.Combining the algorithms improves task assignment in MCS for both total task quality and sensing time.The results demonstrate that combining the two algorithms in LTBA is the best performance for total task quality and total sensing time,and the greedy algorithm follows it then B-DBA.

关键词： Mobile crowdsensing online task assignment participatory sensing path planning sensing time intervals ant colony optimization

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Seismic loss assessment of RC high-rise buildings designed according to Eurocode 8

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 807-824页

作者： Jelena Pejovic Nina Serdar faculty of Civil Engineering University of MontenegroBulevar Dzordza Vasingtona bbPodgorica 81000Montenegro

A probabilistic seismic loss assessment of RC high-rise(RCHR)buildings designed according to Eurocode 8 and located in the Southern Euro-Mediterranean zone is presented herein.The loss assessment methodology is based on a comprehensive simulation approach which takes into account ground motion(GM)uncertainty,and the random effects in seismic demand,as well as in predicting the damage states(DSs).The methodology is implemented on three RCHR buildings of 20-story,30-story and 40-story with a core wall structural system.The loss functions described by a cumulative lognormal probability distribution are obtained for two intensity levels for a large set of simulations(NLTHAs)based on 60 GM records with a wide range of magnitude(M),distance to source(R)and different site soil conditions(SS).The losses expressed in percent of building replacement cost for RCHR buildings are obtained.In the estimation of losses,both structural(S)and nonstructural(NS)damage for four DSs are considered.The effect of different GM characteristics(M,R and SS)on the obtained losses are investigated.Finally,the estimated performance of the RCHR buildings are checked to ensure that they fulfill limit state requirements according to Eurocode 8.

关键词： RC high-rise buildings seismic loss assessment loss functions nonlinear time-history analysis(NLTHA) cumulative lognormal probability distribution random effects Eurocode 8

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Base lubricants for green stamping:The effects of their structure and viscosity on tribological performance

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Friction 2023年第9期11卷 1741-1754页

作者： Marko POLAJNAR LucijaČOGA Mitjan KALIN Laboratory for Tribology and Interface Nanotechnology Faculty of Mechanical EngineeringUniversity of LjubljanaLjubljana 1000Slovenia

The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed.In this investigation,the tribological performance of four base oils with different chemical structures(paraffinic and naphthenic)and viscosities(2 and 20 cSt),as well as water,was evaluated for the stamping of steel sheets and compared with a non-lubricated contact.Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts.Low-viscosity(LV)naphthenic oil performs very like both high-viscosity(HV)oils.A surprising exception is the LV paraffinic oil,with several-times-higher friction and wear compared to dry contact.This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low,leading to lubricant starvation.In contrast,HV oils provide a sufficiently thick lubricating film,while strong cohesive forces help in the film’s strength,lessening wear,and reducing friction.In thin-film lubrication with LV oils,such as when stamping,it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation,thus ensuring lower friction,less wear,and a longer lifetime of the contact.

关键词： stamping viscosity water paraffinic oil naphthenic oil wetting

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