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SURFACE FINITE ELEmENTS FOR PARABOLIC EQUATIONS

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Journal of Computational mathematics 2007年第4期25卷 385-407页

作者： G. Dziuk C.m. Elliott Abteilung für Angewandte mathematik University of Freiburg Hermann-Herder-Straβe 10 D-79104Freiburg i. BrGermany Department of mathematics University of Sussex Falmer Brighton BN1 9RF United Kingdom

In this article we define a surface finite element method （SFEm） for the numerical solution of parabolic partial differential equations on hypersurfaces F in R^n＋1. The key idea is based on the approximation of F by a polyhedral surface Гh consisting of a union of simplices （triangles for n = 2, intervals for n = 1） with vertices on Г. A finite element space of functions is then defined by taking the continuous functions on Гh which are linear affine on each simplex of the polygonal surface. We use surface gradients to define weak forms of elliptic operators and naturally generate weak formulations of elliptic and parabolic equations on Г. Our finite element method is applied to weak forms of the equations. The computation of the mass and element stiffness matrices are simple and straightforward. We give an example of error bounds in the case of semi-discretization in space for a fourth order linear problem. Numerical experiments are described for several linear and nonlinear partial differential equations. In particular the power of the method is demorrstrated by employing it to solve highly nonlinear second and fourth order problems such as surface Allen-Cahn and Cahn-Hilliard equations and surface level set equations for geodesic mean curvature flow.

关键词： Surface partial differential equations Surface finite element method Geodesic curvature Triangulated surface.

Biochar-compost-based controlled-release nitrogen fertilizer intended for an active microbial community

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Frontiers of Agricultural Science and Engineering 2024年第2期11卷 326-343页

作者： Robiul Islam RUBEL Lin WEI Salman ALANAZI Abdulkarim ALDEKHAIL Anne CmCIDREIRA Xufei YANG Sanjita WASTI Samarthya BHAGIA Xianhui ZHAO Department of Agricultural and Biosystem Engineering South Dakota State UniversityBrookingsSD 57007USA Tickle College of Engineering University of Tennessee KnoxvilleKnoxvilleTN 37996USA Oak Ridge National Laboratory Oak RidgeTN 37830USA

Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers(CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new ***, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer(BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50(dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid(PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures(4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N(ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h(8 days). Fourier-transform infrared spectroscopy(FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry(DSC)tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in t

关键词： Soil microbial community biochar compost controlled-release nitrogen fertilizer polylactic acid spray coating

Optimization of mechanical and Wear Properties of Functionally Graded Al6061/SiC Nanocomposites Produced by Friction Stir Processing(FSP)

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Acta metallurgica Sinica(English Letters) 2015年第5期28卷 584-590页

作者： m.Saadatmand J.Aghazadeh mohandesi Department of mining and metallurgical Engineering Amir Kabir University of Technology

The objective of present work is to apply the friction stir processing （FSP） to fabricate functionally graded SiC particulate reinforced Al6061 composite and investigate the effect of SiC particle mass fraction distribution on the mechanical properties and wear behavior ofAl6061/SiC composite. Regarding the obtained results in this work, with increasing SiC mass fraction, elongation decreased, but hardness enhanced. However, the optimized functionally graded composite with the highest tensile strength and wear resistance was achieved for composite with 10 wt% surface SiC. Also, the results showed that wear resistance and tensile strength decreased for composite with 13 wt% surface SiC, due to reinforcement particle clustering depending on high SiC mass fraction.

关键词： Functionally graded composite Wear mechanical properties Friction stir processing (FSP)

Chemoprevention of esophageal adenocarcinoma

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Gastroenterology Report 2020年第4期8卷 253-260,I0001页

作者： Erik J.Snider Andrew m.Kaz John m.Inadomi William m.Grady Division of Gastroenterology Department of Internal MedicineUniversity of Washington School of MedicineSeattleWAUSA Gastroenterology Section VA Puget Sound Health Care SystemSeattleWAUSA Clinical Research Division Fred Hutchinson Cancer Research CenterSeattleWAUSA

Esophageal adenocarcinoma(EAC)is a major cause of cancer-related death,particularly in Western populations,and is rapidly rising in Asian populations at this *** all EACs develop from the precursor lesion Barrett’s esophagus(BE),which is the most significant risk factor for ***,the rates of progression from BE to EAC are low and patients with BE are ***,any strategy for EAC prevention must carry a low risk of harm in order to be clinically *** current EAC-screening and BE-surveillance methods carry some procedural risk and are burdensome,there is an opportunity for chemoprevention,*** or dietary factors that may prevent BE from progressing to EAC.A variety of candidate chemoprevention therapies have been assessed to ***-pump inhibitors(PPIs)are the best studied and have modest EAC-chemoprevention efficacy in BE patients,with a recent randomized trial showing that high-dose PPI may be more effective than low-dose *** and other non-steroidal anti-inflammatory drugs have moderate quality observational and randomized-trial evidence for preventing progression of BE to EAC,but their risks for harm have precluded their routine clinical *** therapies(statins,metformin,female sex hormones)generally do not have strong evidence to support their use in EAC *** progress has been made in this field,there is still a need for more effective and safe chemoprevention therapies for EAC.

关键词： Barrett’s esophagus esophageal adenocarcinoma chemoprevention

早期认知障碍患者的认知功能和双重任务步态的临床研究

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中国康复医学杂志 2021年第5期36卷 546-552页

作者：钟倩朱奕吴含高雅新孙翠云 Nawab ali 吴希希王彤南京医科大学第一临床医学院江苏省南京市210029 南京医科大学第一附属医院康复医学中心南京大学医学院附属鼓楼医院康复医学科江苏省人民医院钟山康复分院

目的:探索早期认知障碍患者双重任务下步态参数与认知功能之间的关系。方法:本研究共纳入轻度认知障碍者(mCI)20例,主观认知下降者(SCD)34例,认知功能正常者(NC)24例,均采用三维运动捕捉系统及建模仿真分析软件进行单任务及双重任务下... 详细信息

目的:探索早期认知障碍患者双重任务下步态参数与认知功能之间的关系。方法:本研究共纳入轻度认知障碍者(mCI)20例,主观认知下降者(SCD)34例,认知功能正常者(NC)24例,均采用三维运动捕捉系统及建模仿真分析软件进行单任务及双重任务下步态参数(步长、步速、步频、步态周期)的采集与分析。结果:双重任务下mCI组步频(步/min)(102.173±11.941)小于SCD组步频(110.500±10.435)(PmCI组步态周期(s)(1.209±0.133)较NC组步态周期(1.122±0.117)和SCD组步态周期长(1.116±0.102)(Pm)及步速(m/s)下降(PmCI组在双重任务下步速、步频及步态周期均下降(P<0.01)。相关性分析显示步速与记忆和语言功能存在正性相关(P=0.005,r=0.312;P=0.014,r=0.277;P=0.005,r=0.317),步频与记忆功能存在正性相关(P=0.010,r=0.289;P=0.012,r=0.283),步态周期与记忆功能存在负性相关(P=0.001,r=﹣0.354),与执行功能存在正性相关(P=0.022,r=0.258)。结论:双重任务下步态参数可作为早期评估认知功能的辅助指标。

关键词：轻度认知障碍主观认知下降双重任务步态分析

HIGH-TEmPERATURE OXIDATION OF FGH96 P/m SUPERALLOY

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Acta metallurgica Sinica(English Letters) 2007年第2期20卷 102-110页

作者： F.J. Liu m.C. Zhang J.X. Dong Y. W. Zhang School of materials Science and Engineering University of Science and Technology BeijingBeijing 100083 China Central Iron and Steel Research Institute Beijing 100081 China

High temperature oxidation behaviors of FGH96 P/m superaUoy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing, X-ray diffraction, SEm （scanning electron microscopy）, and EDS （energy dispersive X-ray spectroscopy） analyses, the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased, the oxidation rate, the scale thickness, and scale spallation increased. FGH96 P/m superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law, and the oxide layer was mainly composed of Cr2O3 TiO2 and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium. titanium, and oxygen through the oxide scale.

关键词： FGH96 P/m superalloy high temperature oxidation oxide scale

New opportunities and challenges in surveying underground cavities using photogrammetric methods

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International Journal of mining Science and Technology 2021年第1期31卷 9-13页

作者： malte J.m.Gurgel Axel Preusse Institute for mine Surveying Mining Subsidence Engineering and Geophysics in MiningRWTH Aachen UniversityAachen 52062Germany

The exploitation of the underground is currently undergoing a major transformation *** mining,alternative ways of utilization are playing an increasingly important *** alternative utilizations include the storage of gases,the disposal of radioactive wastes,and the implementation of geothermal storage *** addition,more and more mining operations are being shut down,like the German hard coal mining industry in *** the integrity of closed mines must be ensured in the post-mining *** order to capture such large and complex structures efficiently and reliably,new surveying techniques are required.A promising approach is the use of photogrammetric methods to generate three-dimensional models of the *** is currently known mainly from aerial *** is conceivable to use such methods for underground *** recent years,significant progress has been made in the algorithm-based orientation of unstructured image *** powerful computer systems and the growing range of unmanned aerial vehicles could enable partially automated ***,a number of problems have to be solved for underground imaging *** exposure conditions complicate image ***,the models must be integrated into existing surveying systems with a sufficiently high degree of *** order to consider the numerous technical aspects,the development of an integrated capture and evaluation approach is *** could make an important contribution to the monitoring of critical cavities of different *** an approach would also fit into the current digitization trend in the mining industry and provide new opportunities for ground control in particular.

关键词： Photogrammetry Surveying Subsurface spatial planning

Cost Effective Optimal Task Scheduling model in Hybrid Cloud Environment

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Computer Systems Science & Engineering 2022年第9期42卷 935-948页

作者： m.manikandan R.Subramanian m.S.Kavitha S.Karthik Department of Computer Science&Engineering Sri Krishna College of Engineering and TechnologyCoimbatore641008India Department of Electrical and Electronics Engineering SNS College of TechnologyCoimbatore641035India Department of Computer Science&Engineering SNS College of TechnologyCoimbatore641035India

In today’s world, Cloud Computing (CC) enables the users to accesscomputing resources and services over cloud without any need to own the infrastructure. Cloud Computing is a concept in which a network of devices, located inremote locations, is integrated to perform operations like data collection, processing, data profiling and data storage. In this context, resource allocation and taskscheduling are important processes which must be managed based on the requirements of a user. In order to allocate the resources effectively, hybrid cloud isemployed since it is a capable solution to process large-scale consumer applications in a pay-by-use manner. Hence, the model is to be designed as a profit-driven framework to reduce cost and make span. With this motivation, the currentresearch work develops a Cost-Effective Optimal Task Scheduling model(CEOTS). A novel algorithm called Target-based Cost Derivation (TCD) modelis used in the proposed work for hybrid clouds. moreover, the algorithm workson the basis of multi-intentional task completion process with optimal resourceallocation. The model was successfully simulated to validate its effectivenessbased on factors such as processing time, make span and efficient utilization ofvirtual machines. The results infer that the proposed model outperformed theexisting works and can be relied in future for real-time applications.

关键词： Cost effectiveness hybrid cloud optimal task scheduling virtual machine resource allocation make span

A Novel Energy Lifting Approach Using J-Function and Flow Zone Indicator for Oil Fields

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Energy Engineering 2022年第1期119卷 253-273页

作者： m.N.Tarhuni W.R.Sulaiman m.Z.Jaafar K.m.Sabil School of Chemical and Energy Engineering Universiti Teknologi MalaysiaSkudaiJohor81310Malaysia School of Energy GeoscienceInfrastructure and SocietyHeriot-Watt University MalaysiaWilayah Persekutuan Putrajaya62200Malaysia

The X field is located in the southwestern part of block NX89 of Kentan Basin in *** field is produced from Hailan multilayer consolidated sandstone with moderate rock property and a relatively low energy *** reserve of subsurface energy sources is declining with ***,techniques were combined to achieve the energy optimization and increase hydrocarbon *** order to understand the subsurface formation of the reservoir and facilitate oil production,global hydraulic element technique was used to quantify the reservoir rock *** addition,stratigraphic modified Lorenz plot was used for reservoir *** heterogeneity was identified using stratigraphic modified Lorenz plot and Dykstra-Parsons *** J-functionwas used to average the 13 capillary pressure curves into four main curves to represent the whole reservoir based on flow zone indicator *** pressure was calculated and plotted with normalized water saturation;a single average curve was defined to represent the rest of the *** saturation was calculated using single and multiple J-functions and compared with the available *** multiple J-functions,the matching results were good for both high and low-quality layers,whereas using a single J-function,the match was poor,especially for low FZI layers such as H4c and *** rock types were identified for this reservoir ranging from medium to good reservoir quality and six different layers were *** reservoir was heterogeneous with a Lorenz coefficient value of approximately 0.72 and a Dykstra-Parsons value of *** approaches used in this paper were validated and showed improved hydrocarbon recovery factor.

关键词： Energy lifting special core analysis flow zone indicator reservoir heterogeneity water saturation Leverett J-function