检索结果-南通市图书馆

An Innovative Finite Element Geometric Modeling of single-Layer Multi-Bead WAAMed Part

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & sciences 2024年第3期138卷 2383-2401页

作者： Xiangman Zhou Jingping Qin Zichuan Fu Min Wang Youlu Yuan Junjian Fu Haiou Zhang seyed reza elmi hosseini College of Mechanical and Power Engineering China Three Gorges UniversityYichang443002China school of Mechanical science and Engineering Huazhong University of Science and TechnologyWuhan430074China school of Metallurgy and Materials Engineering Iran University of Science and TechnologyNarmakIran

Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.

关键词： WAAM FE coupled thermal-mechanical analysis the isosceles trapezoid-based model residual stress

Effect of thermal maturation and organic matter content on oil shale fracturing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal science & Technology 2024年第2期11卷 16-34页

作者： Fatemeh saberi Mahboubeh hosseini‑Barzi Department of Geology and Geological Engineering University of North Dakota264 Centennial DriveGrand ForksNDUSA Department of Geology and Petroleum Basins Shahid Beheshti University of TehranTehranTehran ProvinceIran

The Pabdeh Formation represents organic matter enrichment in some oil fields,which can be considered a source *** study is based on the rock–Eval,Iatroscan,and electron microscopy imaging results before and after heating the *** discovered this immature shale that undergoes burial and diagenesis,in which organic matter is converted into *** migration is the process that transports hydrocarbons in the source *** investigated this phenomenon by developing a model that simulates hydrocarbon generation and fluid pressure during kerogen-to-hydrocarbon *** initially formed at the tip/edge of kerogen and were filled with hydrocarbons,but as catagenesis progressed,the pressure caused by the volume increase of kerogen decreased due to hydrocarbon *** transformation of solid kerogen into low-density bitumen/oil increased the pressure,leading to the development of damage zones in the source *** Pabdeh Formation’s small porethroats hindered effective expulsion,causing an increase in pore fluid pressure inside the initial *** stress accumulated due to hydrocarbon production,reaching the rock’s fracture strength,further contributed to damage zone *** the expansion process,microfractures preferentially grew in low-strength pathways such as lithology changes,laminae boundaries,and pre-existing *** the porous pressure created by each kerogen overlapped,individual microfractures interconnected,forming a network of microfractures within the source *** research sheds light on the complex interplay between temperature,hydrocarbon generation,and the development of expulsion fractures in the Pabdeh Formation,providing valuable insights for understanding and optimizing hydrocarbon extraction in similar geological settings.

关键词： Oil shale Microfracture Hydrocarbon generation Organic matter Thermal maturation Primary migration

Developing a phenomenological model to simulate single and mixed scale formation during flow in porous media:Coupling a salt precipitation model with an ion transport equation under dynamic conditions

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 research 2024年第1期9卷 17-36页

作者： Erfan hosseini Dana Mohammad Nazar Negar hosseini Mohammad sarmadivaleh Exploration Directorate National Iranian Oil Company(NIOC)TehranIran Institute of Physical Chemistry and Polymer Physics Leibniz Institute of Polymer Research DresdenDresdenGermany Department of Petroleum Engineering Islamic Azad University(IAU)IlamIran WA school of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityPerthWestern AustraliaAustralia

Water flooding and pressure maintenance are recommended to improve oil recovery practices after low recovery of petroleum reservoirs occurs during primary *** crystal formation is a frequent occurrence when using these *** experimental,numerical,and theoretical studies have been done on the mechanisms underlying scaling and permeability reduction in porous media;however,there has not been a satisfactory model *** study developed a phenomenological model to predict formation damage caused by salt *** with existing models,which provide a scaling tendency,the proposed model predicts the profile of scale *** salt precipitation model simulates reactive fluid flow through porous media.A thermodynamic,kinetic,and flow hydrodynamic model was developed and coupled with the ion transport equation to describe the movement of ***,a set of carefully designed dynamic experiments were conducted and the data were compared with the model *** forecasts and experimental data were observed to have an average absolute error(AAE)ranging from 0.68%to 5.94%,which indicates the model's suitability.

关键词： Improved oil recovery Water flooding Formation damage scaling tendency salt precipitation

solar and wind energy potential assessment for razavi Khorasan Province in Iran

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 Central south University 2024年第6期31卷 2027-2038页

作者： hosseini Amirpouya rAMEZANI Faeze MIrhosseini Mojtaba school of Advanced Technologies Iran University of Science and TechnologyTehranIran

This study aims to evaluate the solar and wind energy potential across razavi Khorasan Province,Iran,with a specific focus on the Khaf region.A preliminary assessment of mean solar radiation,mean wind speeds,and Weibull distribution parameters was conducted for different towns and zones within the *** findings showed that Khaf has favorable characteristics for further *** solar and wind energy metrics examined include global horizontal irradiance,clearness index,wind rose patterns,and turbulence *** a height of 40 m,Khaf’s wind power density reached 1650 W/m^(2),indicating exceptional wind energy generation ***,Khaf received an average annual solar radiation of 2046 kW·h/m^(2),representing significant solar energy *** these substantial renewable resources in Khaf could allow razavi Khorasan Province to reduce reliance on fossil fuels,improve energy sustainability,and mitigate climate change *** research contributes an in-depth assessment of razavi Khorasan's solar and wind energy potential,particularly for the promising Khaf *** work may examine optimal sites for renewable energy projects and grid integration strategies to leverage these resources.

关键词： solar energy wind energy razavi Khorasan radiation Weibull distribution

Theoretical framework of the Isfahani style: Inspiring sustainable aspects of a vernacular urban development

在线全文

学校读者我要写书评

暂无评论

Frontiers of Architectural research 2024年第2期13卷 349-369页

作者： Hatef Jafari sharami seyed Jamalaldin hosseini Department of Architecture and Urbanism University of EyvanekeyEyvanekey 99888-35918Iran Faculty of Civil and Architecture University of EyvanekeyEyvanekey 99888-35918Iran

The Isfahani style represents a method of traditional Iranian architecture and urban development that existed in the early 20th century and is regarded as a leading model in most traditional Iranian cities. It exhibits several vigorous features contributing to its recognition as a traditional approach to sustainable architecture and urban development. This research endeavors to reveal a theoretical framework beneath these inspiring aspects using the typology of sustainable modern forms, including the hierarchy, passive design strategies, compactness, density, diversity, mixed land use, pluralism, balance, good composition, and integration over time. To this end, the study employs qualitative research methods, drawing from traditional samples, to identify innovative, energy and socially efficient, and low-impact strategies implemented in this vernacular architecture of Iran's semi-arid and hot climates. The findings revealed that the neighborhood concept as a local and plural community (Mahalla) was a vital phenomenon in Iran's urban development. Apparently, the demise of this paradigm effectively played an important role in the numerous challenges regarding the social, energy, and economic viability of modern Iranian cities. Hence, this study presented theoretical frameworks—aligned with sustainable concepts—from the Isfahani style through its analysis, classification, and interpretation, which can contribute to modern urban development.

关键词： Isfahani style Vernacular urban development sustainable urban development Iranian cities Vernacular architecture

simulation of Case Depth of Cementation steels According to Fick’s Laws

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and steel research International 2012年第11期19卷 71-78页

作者： s.r.elmi hosseini Faculty of Engineering Department of Materials Science and EngineeringUniversity of Sistan and Baluchestan

The carburizing process is the enrichment of the depth of low carbon steels with carbon. It leads to samples with a combination of high surface hardness and high core toughness and to an impact strength that is required for many engineering parts. The material studied is a low carbon steel. The carbon content is little in this type of steel （wc = 0.2 ~）. The calculation of case depth is very important for cementation steels that are hardened in the carburi- zing process. The effective case depth is defined as the perpendicular distance from the surface to a place at which the hardness is HV 550. Nowadays, a great number of studies have been carried out on the simulation of effective case depth, but no studies have been conducted to determine the numerical relation between the total case depth on one hand and the carburizing time and the effective case depth on the other hand. The steel specimens were subjected to graphite powder. Then, they were heat treated at 925 ~C for about 3, 5, 8 and 12 h, respectively. Then, these parts were quenched in oil. To determine the effective case depth, the micr0hardness test was performed on the cross-section of specimens. Plotting the case depth vs carburizing time, the required conditions for obtaining the specified case depth were determined. Also, the comparison between the case depths in numerical solution and the actual position in pack carburizing was performed.

关键词： cementation steel carburizing case depth Fick's law simulation

An efficient tool for Parkinson's disease detection and severity grading based on time-frequency and fuzzy features of cumulative gait signals through improved LsTM networks

在线全文

学校读者我要写书评

暂无评论

Medicine in Novel Technology and Devices 2024年第2期22卷 38-50页

作者： Farhad Abedinzadeh Torghabeh Yeganeh Modaresnia seyyed Abed hosseini Department of Biomedical Engineering Mashhad BranchIslamic Azad UniversityMashhadIran Department of Electrical Engineering Mashhad BranchIslamic Azad UniversityMashhadIran

Parkinson's disease(PD)is a widespread neurodegenerative condition that affects many individuals *** identification and monitoring of disease progression are crucial to effectively managing symptoms and preventing motor *** research proposes an automated PD diagnosis and severity-grading model based on time-frequency and fuzzy features using improved uni-directional and bi-directional long short-term memory networks with sensitive hyperparameters *** utilize vertical ground reaction force signals collected from Physionet's publicly available dataset recorded during regular and dual-task clinical trials of walking *** the cumulative signal of both feet was then utilized and segmented into 30-s windows without further ***,we extracted only four key time-frequency and fuzzy features from each segment,effectively capturing the signal's inherent *** optimization is employed in both detection and grading approaches to fine-tune the two critical hyperparameters:the initial learning rate and the number of hidden units in the *** detection phase yields an exceptional accuracy of 99.19%,surpassing state-of-the-art studies with the same *** the grading phase,classification based on the unified PD rating scale values achieves an accuracy of 92.28%.The proposed study delves into the potential of cumulative gait signals as a powerful diagnostic tool for PD,aiming to extract precise and intricate information by implementing straightforward and minimal processing *** method demonstrates significant effi-ciency in terms of complexity,cost,and energy consumption by utilizing a single-dimensional signal,eliminating the need for pre-processing steps,and limiting the features used for training.

关键词： Parkinson's disease grading Cumulative gait signal Vertical ground reaction force fuzzy feature Bayesian optimization Long short-term memory

New insights on the role of chondroitin sulfate proteoglycans in neural stem cell–mediated repair in spinal cord injury

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural regeneration research 2025年第6期20卷 1699-1700页

作者： seyed Mojtaba hosseini soheila Karimi-Abdolrezaee Department of Physiology and Pathophysiology Spinal Cord Research CentreRady Faculty of Health SciencesUniversity of ManitobaWinnipegMBCanada Manitoba Multiple sclerosis research Center WinnipegMBCanada Children Hospital research Institute of Manitoba WinnipegMBCanada

Extensive neurodegeneration is a hallmark of traumatic spinal cord injury (sCI) that underlies permanent sensorimotor and autonomic impairments (Alizadeh et al.,2019).Following the primary impact,the spinal cord undergoes a cascade of secondary injury mechanisms that are driven by disruption of the blood-spinal cord ba rrier,vascula r inju ry,glial reactivity,neu roinfla mmation,oxidative stress,lipid peroxidation,and glutamate excitotoxicity that culminate in neuronal and oligodendroglial cell death,demyelination,and axonal damage(Alizadeh et al.,2019).To achieve a meaningful functional recovery after sCI,regeneration of new neurons and oligodendrocytes and their successful growth and integration within the neural network are critical steps for reconstructing the damaged spinal cord tissue (Fischer et al.,2020).

关键词： peroxidation Fischer injury

Influence of soaking time in deep cryogenic treatment on the microstructure and mechanical properties of low-alloy medium-carbon HY-TUF steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第6期23卷 658-666页

作者： Ahmad Zare s.r.hosseini Department of Materials Engineering Maleke-ashtar University of Technology

The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distribution mapping by electron backscatter diffraction show that the deep cryogenic process causes a decrease in the content of retained austenite and an increase in the volume fraction of η-carbide with increasing soaking time up to 48 h. The decrease in the content of retained austenite from ~1.23vol% to 0.48vol% suggests an isothermal martensitic transformation at 77 K. The η-type precipitates formed in deep cryogenic-treated martensite over 48 h have the Hirotsu and Nagakura orientation relation with the martensitic matrix. Furthermore, a high coherency between η-carbide and the martensitic matrix is observed by high-resolution transmission electron microscopy. The variations in macrohardness, yield strength, ultimate tensile strength, and ductility with soaking time in the deep cryogenic process show a peak/plateau trend.

关键词： low alloy steel medium carbon steel cryogenic treatment microstructure mechanical properties fractography