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Modeling of fiber bridging in fluid flow for well stimulation applications

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Petroleum Science 2020年第3期17卷 671-686页

作者： Mehdi Ghommem Mustapha Abbad Gallyam Aidagulov steve Dyer Dominic Brady Department of Mechanical Engineering American University of ShaijahSharjah 26666United Arab Emirates Schlumberger Dhahran Carbonate Research Center Dammam/Doha Camp 31942Kingdom of Saudi Arabia Schlumberger Completions RosharonTX 77583USA

Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation *** materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix *** the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not *** current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular *** is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and *** modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage *** this work,we develop a numerical model to study fiber dynamics in fluid *** employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected *** discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous *** focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in *** trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental *** present numerical investigation reveals that the bridging capability of the fi

关键词： Fiber bridging Fiber flocculation Modeling and numerical simulation Discrete element method Fiber-fluid coupling Sensitivity analysis

Droplet digital microfluidic system for screening filamentous fungi based on enzymatic activity

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Microsystems & Nanoengineering 2022年第6期8卷 97-112页

作者： Kenza Samlali Chiara Leal Alves Mara Jezernik steve C.C.Shih Department of Electrical and Computer Engineering Concordia UniversityMontréalQCCanada Centre for Applied Synthetic Biology Concordia UniversityMontréalQCCanada Department of Chemical Engineering and Applied Chemistry University of TorontoTorontoONCanada Department of Biology Concordia UniversityMontréalQCCanada

Fungal cell-wall-degrading enzymes have great utility in the agricultural and food *** cell-wall-degrading enzymes are known to have functions that can help defend against pathogenic *** existing methods used to discover these enzymes are not well adapted to fungi culture and morphology,which prevents the proper evaluation of these *** report the first droplet-based microfluidic method capable of long-term incubation and low-voltage conditions to sort filamentous fungi inside nanoliter-sized *** new method was characterized and validated in solid-phase media based on colloidal chitin such that the incubation of single spores in droplets was possible over multiple days(2–4 days)and could be sorted without droplet *** long-term culture,we examined the activity of cell-wall-degrading enzymes produced by fungi during solid-state droplet fermentation using three highly sensitive fluorescein-based *** also used the low-voltage droplet sorter to select clones with highly active cell-wall-degrading enzymes,such as chitinases,β-glucanases,and β-Nacetylgalactosaminidases,from a filamentous fungi droplet library that had been incubated for>4 *** new system is portable,affordable for any laboratory,and user-friendly compared to classical droplet-based microfluidic *** propose that this system will be useful for the growing number of scientists interested in fungal microbiology who are seeking high-throughput methods to incubate and sort a large library of fungal cells.

关键词： system fluid culture

A Study of the Energy Management System in the Georgetown Public Hospital Cooperation (GPHC) in Guyana

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A Study of the Energy Management System in the Georgetown Pu...

作者： steve Ramsarran 湖南大学

学位级别：硕士

医院是全球医疗健康系统的支柱,本文对位于圭亚那乔治敦市的乔治敦公立医院(GPHC)的能量管理系统进行了研究。能量管理可以描述为通过不断努力降低能耗来提高现有医院能量利用效率的一种方式,包括以维持所获得的能量效率收益的方式来运... 详细信息

医院是全球医疗健康系统的支柱,本文对位于圭亚那乔治敦市的乔治敦公立医院(GPHC)的能量管理系统进行了研究。能量管理可以描述为通过不断努力降低能耗来提高现有医院能量利用效率的一种方式,包括以维持所获得的能量效率收益的方式来运营和维护医院。该研究是从乔治敦公立医院能量管理系统的角度进行的,以证明实施能量管理计划的重要性。本文分析了2018年乔治敦公立医院能量载体及其消费结构,结果表明:日常用电折算的燃料消耗了855.5吨,用于产生蒸汽的燃料消耗了156.2吨,用于应急发电的液化石油气消耗了12.2吨,用于发电的柴油消耗了4.2吨。另外,本文还确定了能源消耗的总体指标和通用指数,结果表明:该医院2018年病人每日人均能源消费为8.20 kg,大约消费9.82美元(USD)。从温室气体排放(GHG)分析,等效CO对健康有害,同时,日常用电是最高的能量载体且明确了耗电量最多的设备。本文通过对往年数据进行分析,获得了每个能量载体的消耗率,并计算了能量载体每年的总成本,根据锅炉和柴油发电机计算了温室气体排放量。等效二氧化碳是影响最大的气体,质量为50153740 kg千克。

关键词：医院能源管理系统能量载体指标和温室气体

Research on the atomic force microscopy-based fabrication of nanochannels on silicon oxide surfaces

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Chinese Science Bulletin 2010年第30期55卷 3466-3471页

作者： WANG ZhiQian JIAO NianDong TUNG steve DONG ZaiLi State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Mechanical Engineering University of Arkansas Fayetteville Arkansas 72701 USA

The atomic force microscopy (AFM)-based nanomachining of nanochannels on silicon oxide surfaces is investigated both theoretically and experimentally. The relationships of nanochannel depth versus cutting velocity,nanochannel depth versus normal force,friction force versus cutting velocity,and friction force versus normal force are systematically studied. Using the derived theory and fabrication method,a nanochannel with an expected depth can be machined simply by controlling the vertical deflection signal on the position sensitive detector of AFM. The theoretical analysis and fabrication method can be effectively used for AFM-based fabrication of nanochannels.

关键词：原子力显微镜表面氧化硅氧化物基础位置敏感探测器制造纳米通道切割速度

Awareness and Impact of Intellectual Property Rights among E-Waste Recyclers in Ghana

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Awareness and Impact of Intellectual Property Rights among E...

作者： WEPIA steve 西南科技大学

学位级别：硕士

技术的快速发展、人民生活水平的提高等导致电子垃圾成为世界上增长最快的垃圾,其处理处置不当可能对环境和人类健康造成巨大的有害影响。电子垃圾的循环利用是电子废弃物管理及处理处置的最佳方法。但其循环利用过程受知识产权的限制... 详细信息

技术的快速发展、人民生活水平的提高等导致电子垃圾成为世界上增长最快的垃圾,其处理处置不当可能对环境和人类健康造成巨大的有害影响。电子垃圾的循环利用是电子废弃物管理及处理处置的最佳方法。但其循环利用过程受知识产权的限制。本研究以加纳电子垃圾回收者为研究对象,采用文献调研、实地调查、数据统计分析等方法,讨论加纳回收者对知识产权的认知及知识产权对电子废弃物回收的影响。加纳电子垃圾回收从业人员主要是男性,受教育程度不高;大多数人不知道电子垃圾循环利用中的知识产权问题,绝大部分也不清楚本国的知识产权法,知识产权信息的获取主要源于媒体和教育。加纳电子垃圾回收绝大部分都是非正规的;循环再利用的电子垃圾主要包括手机、冰箱、电视和电脑;回收活动主要包括清洗、分类,修复、翻新、焚烧以获得有价金属;知识产权在许多方面对电子废物的回收产生了影响,如无法获得某些用于修理和翻新的零件等;建议确保加纳电子垃圾无冲突回收。论文研究有助于认识加纳电子垃圾回收的现状,提高加纳电子垃回收从业者及民众对知识产权的认识,对国际电子垃圾回收管理具有一定的意义。

关键词：知识产权电子废物回收利用加纳

Mercury concentrations in blood and feathers of nestling Bald Eagles in coastal and inland Virginia

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Avian Research 2019年第1期10卷 36-42页

作者： David E.Kramar Bill Carstensen steve Prisley Jim Campbell Department of Anthropology and Earth Science Minnesota State University Moorhead Department of Geography Virginia Tech National Council for Air and Stream Improvement

Background:Mercury(Hg) and methylmercury are widely considered significant issues for wildlife,and in particular,piscivorous birds due to their widespread availability and neurotoxic *** a substantial number of studies of Hg contamination of Bald Eagles(Haliaeetus leucocephalus) have been conducted throughout the east coast of the United States,little has been done that directly addresses Hg contamination in Bald Eagles in Virginia,particularly the inland ***:We collected blood and feather samples from nestling Bald Eagles in the coastal plain,piedmont,and western regions of Virginia in an effort to determine which areas of the state were more likely to contain populations showing evidence of Hg *** analyzed the samples for total Hg using a Milestone ***:Samples collected from individuals located in the coastal region exhibited low concentrations of Hg compared to those further inland located on freshwater rivers and *** collected from the inland population exhibited levels in some areas that are approaching what may be considered to be sub-lethal to avian health(blood:mean 0.324 mg/kg,SE = 0.13,range = 0.06-0.97 mg/kg;feather:mean = 8.433 mg/kg,SE = 0.3,range = 3.811-21.14 mg/kg).Conclusions:Even after accounting for known point-sources of Hg,the inland eagle population in Virginia is susceptible to concentrations of Hg that are significantly higher than their coastal ***,several locations besides those currently known to be impacted by point-sources are exhibiting concentrations that are approaching a sub-lethal level.

关键词： Bald Eagle Haliaeetus leucocephalus Mercury Methyl-mercury Virginia

Underworld-GT Applied to Guangdong,a Tool to Explore the Geothermal Potential of the Crust

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Journal of Earth Science 2015年第1期26卷 78-88页

作者： steve Quenette Yufei Xi John Mansour Louis Moresi David Abramson Monash e Research Centre Monash UniversityClayton 3800Australia The Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological Sciences School of Earth Sciences The University of MelbourneMelbourne 3010Australia Research Computing Centre The University of QueenslandSt Lucia 4072Australia

Geothermal energy potential is usually discussed in the context of conventional or engineered systems and at the scale of an individual reservoir. Whereas exploration for conventional reservoirs has been relatively easy, with expressions of resource found close to or even at the surface, exploration for non-conventional systems relies on temperature inherently increasing with depth and searching for favourable geological environments that maximise this increase. To utilitise the information we do have, we often assimilate available exploration data with models that capture the physics of the domi- nant underlying processes. Here, we discuss computational modelling approaches to exploration at a regional or crust scale, with application to geothermal reservoirs within basins or systems of basins. Target reservoirs have （at least） appropriate temperature, permeability and are at accessible depths. We discuss the software development approach that leads to effective use of the tool Underworld. We explore its role in the process of modelling, understanding computational error, importing and exporting geological knowledge as applied to the geological system underpinning the Guangdong Province, China.

关键词： Underworld-GT geothermal potential computational modelling approach Guangdong.

Correlating Bladder Cancer Risk Genes with Their Targeting MicroRNAs Using MMiRNA-Tar

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Genomics, Proteomics & Bioinformatics 2015年第3期13卷 177-182页

作者： Yang Liu steve Baker Hui Jiang Gary Stuart Yongsheng Bai Department of Electrical and Computer Engineering Rose-Hulman Institute of Technology Department of Math and Computer Science Indiana State University Department of Biostatistics University of Michigan Department of Biology Indiana State University The Center for Genomic Advocacy Indiana State University

The Cancer Genome Arias （TCGA）（http：//***） is a valuable data resource focused on an increasing number of well-characterized cancer genomes. In part, TCGA provides detailed information about cancer-dependent gene expression changes, including changes in the expression of transcription-regulating microRNAs. We developed a web interface tool MMiRNA-Tar （http：f/***-Tar） that can calculate and plot the correlation of expression for mRNA-microRNA pairs across samples or over a time course for a list of pairs under different prediction confidence cutoff criteria. Prediction confidence was estab- lished by requiring that the proposed mRNA-microRNA pair appears in at least one of three target prediction databases： TargetProfiler, TargetScan, or miRanda. We have tested our MMiRNA-Tar tool through analyzing 53 tumor and 11 normal samples of bladder urothelial carcinoma （BLCA） datasets obtained from TCGA and identified 204 microRNAs. These microRNAs were correlated with the mRNAs of five previously-reported bladder cancer risk genes and these selected pairs exhib- ited correlations in opposite direction between the tumor and normal samples based on the cus- tomized cutoff criterion of prediction. Furthermore, we have identified additional 496 genes （830 pairs） potentially targeted by 79 significant microRNAs out of 204 using three cutoff criteria, i.e.,false discovery rate （FDR）〈 0.1, opposite correlation coefficient between the tumor and normal samples, and predicted by at least one of three target prediction databases. Therefore, MMiRNA- Tar provides researchers a convenient tool to visualize the co-relationship between microRNAs and mRNAs and to predict their targeting relationship. We believe that correlating expression profiles for microRNAs and mRNAs offers a complementary approach for elucidating their interactions.

关键词： The Cancer Genome Atlas Bladder cancer MicroRNA mRNA Correlation Target prediction

Two Bioinspired Mobile Manipulators with Rolling Locomotion

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Journal of Bionic Engineering 2016年第1期13卷 48-58页

作者： Saber Mahboubi Heydarabad Mir Masoud Seyyed Fakhrabadi steve Davis Samia Nefti-Meziani School of Computing Science & Engineering University of Salford Manchester The Crescent M5 4WT UK School of Mechanical Engineering College of Engineering University of Tehran Tehran Iran

This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing to increase the robot ma- neuverability. Indeed, the capability of rolling motion is added to ordinary quadruped robots. This capability causes increment in maneuvering of the robots. Manipulators can be embedded into the robots to add the ability of transferring materials into the shell and conducting some tasks such as repairing. In this paper, after analysis of motion principles of the rolling robots, their dynanlic equations are derived. Different simulations of two bioinspired mobile robots are presented in order to scrutinize various capabilities of the proposed designs. Walking capabilities of the robots and their advantages are discussed in detail. The comprehensive simulation results of the robots in various motion modes are presented. Finally the first prototype is introduced to verify the motion mechanisms.

关键词： bionics rolling robot quadruped robot Lagrange equations