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Moving computational multi-domain method for modelling the flow interaction of multiple moving objects

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Advances in Aerodynamics 2022年第1期4卷 78-95页

作者： Momoha Nishimura Masashi Yamakawa Shinichi Asao Seiichi Takeuchi mehdi Badri Ghomizad Department of Mechanical and System Engineering Kyoto Institute of TechnologyKyotoJapan Department of Mechanical Engineering College of Industrial TechnologyHyogoJapan

This study proposes a method for modelling the flow interaction of multiple moving objects where the flow field variables are communicated between multiple separate moving computational *** of using the conventional approach with a single fixed computational domain covering the whole flow field,this method advances the moving computational domain(MCD)method in which the computational domain itself moves in line with the motions of an object *** computational domains created around each object move independently,and the flow fields of each domain interact where the flows *** eliminates the spatial restriction for simulating multiple moving ***,a shock tube test verifies that the overset implementation and grid movement do not adversely affect the results and that there is communication between the grids.A second test case is conducted in which two spheres are crossed,and the forces exerted on one object due to the other’s crossing at a short distance are *** results verify the reliability of this method and show that it is applicable to the flow interaction of multiple moving objects.

关键词： Crossing Moving boundary problems Compressible flow Moving mesh method

A Study on Flame Forming of Bowl Shaped Surface with Various Spiral Irradiating Schemes

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Acta Mechanica Solida Sinica 2016年第3期29卷 328-336页

作者： mehdi Safari Department of Mechanical Engineering Arak University of Technology

In this paper, various strategies of spiral irradiating scheme for the flame forming of a bowl shaped surface are investigated experimentally and numerically. Experimental work is performed using a flame torch integrated with a 2-axis CNC workstation. The ABAQUS implicit solver is used in the numerical simulation. Three different strategies of the spiral irradiating scheme are investigated for the flame forming of a bowl shaped surface. The first strategy is the Simple spi- ral irradiating scheme, the second is the Rotational spiral irradiating scheme, and the third is the Symmetrical-Rotational spiral irradiating scheme. The results show that using the Symmetrical- Rotational spiral irradiating scheme, a bowl shaped surface with the maximum deformation can be produced, followed by using the Rotational scheme, and the Simple spiral scheme. It is also concluded from the results that the spiral irradiating scheme with Symmetrical-Rotational, Rota- tional and Simple spiral schemes lead to the maximum symmetries in the produced bowl shaped surface, respectively. All the numerical results are in good agreement with the experimental ob- servations.

关键词： flame forming bowl shaped surface spiral irradiating strategy

BLUNT CRACK-TIP ELASTOPLASTIC ZONE OF MIXED MODE FRACTURE

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Acta Mechanica Solida Sinica 2014年第5期27卷 531-541页

作者： mehdi Khojastehpour Department of Biosystems Engineering Ferdowsi University of Mashhad

This article discusses the characterization of fracture process zone at the tip of a blunt crack in elastoplastic materials under mixed mode loading. The analysis includes the description of elastoplastic zone geometry around the blunt crack tip for predicting crack growth direction. The deformed zone appearing at the crack front is described by presenting a criterion based on the subloading surface concept falling within the framework of unconventional plasticity. The mixed mode crack propagates along the minimum value of the elastoplastic region. The present solutions are reduced to those previously reported in literature, when the elastic perfectly plastic material is considered.

关键词： crack fracture elastic plastic materials stress concentration

Epidemiological aspect of retinoblastoma in the world: a review of recent advance studies

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International Journal of Ophthalmology(English edition) 2023年第6期16卷 962-968页

作者： Leili Koochakzadeh Abbasali Yekta Hassan Hashemi Reza Pakzad Samira Heydarian mehdi Khabazkhoob Department of Pediatrics Children’s Medical Center HospitalTehran University of Medical SciencesTehran ***Iran Refractive Errors Research Center Mashhad University of Medical SciencesMashhad 3453545Iran Noor Research Center for Ophthalmic Epidemiology Noor Eye HospitalTehran ***Iran Department of Epidemiology Faculty of HealthIlam University of Medical SciencesIlam ***Iran Department of Rehabilitation Science School of Allied Medical SciencesMazandaran University of Medical SciencesSari ***Iran Department of Basic Sciences School of Nursing and MidwiferyShahid Beheshti University of Medical SciencesTehran ***Iran

·AIM: To collect and present updated evidence about epidemiological aspects of retinoblastoma(Rb) in the world.·METHODS: A comprehensive search without the time and language restrictions was conducted in international databases, including MEDLINE, Scopus, Web of Science, and Pub Med. The search keywords were “retinoblastoma” OR “retinal Neuroblastoma” OR “retinal glioma” OR “retinoblastoma eye cancer” OR “retinal glioblastoma”.·RESULTS: The worldwide incidence of Rb is 1 in 16 000-28 000 live births, but was higher in developing compared to developed countries. Several attempts for improving early detection and treatment had increased the Rb survival rate from 5% to 90% in developed countries over the past decade, but its survival was lower in developing countries(about 40% in low-income countries) and the majority of mortalities occurred in developing countries. The etiology of Rb could be viewed as genetics in the heritable form and environmental and lifestyle factors in the sporadic form. Some environmental risk factors such as in vitro fertilization;insect sprays;father’s occupational exposure to oil mists in metal working, and poor living conditions might play a role in the occurrence of the disease. Although ethnicity might affect Rb incidence, sex has no documented effect and the best treatment approaches were now ophthalmic artery chemosurgery and intravitreal chemotherapy.·CONCLUSION: Determining the role of genetics and environmental factors helps to accurately predict the prognosis and identify the mechanism of the disease, which can reduce the risk of tumor development.

关键词： epidemiology retinoblastoma leukocoria children RB1 gene

Dieback intensity but not functional and taxonomic diversity indices predict forest productivity in different management conditions: Evidence from a semi-arid oak forest ecosystem

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Journal of Arid Land 2022年第2期14卷 225-244页

作者： Mona KARAMI mehdi HEYDARI Ali SHEYKHOLESLAMI Majid ESHAGH NIMVARI Reza OMIDIPOUR YUAN Zuoqiang Bernard PREVOSTO Faculty of Natural Resources Chalus BranchIslamic Azad UniversityChalus 46615/397Iran Department of Forestry Chalous BranchIslamic Azad UniversityChalous 46615/397Iran Department of Rangeland and Watershed Management Faculty of Natural Resources and Earth SciencesShahrekord UniversityShahrekord ***Iran Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110164China INRAE Aix Marseille UniversityUMR RECOVERMediterranean Ecosystems and RisksAix-en-Provence 13128France

The relationships between different aspects of diversity(taxonomic,structural and functional)and the aboveground biomass(AGB)as a major component of global carbon balance have been studied extensively but rarely under the simultaneous influence of forest dieback and *** this study,we investigate the relationships between taxonomic,functional and structural diversity of woody species(trees and shrubs)and AGB along a gradient of dieback intensity(low,moderate,high and no dieback as control)under two contrasted management conditions(protection by central government *** management by natives)in a semi-arid oak(Quereus brantii Lindl.)forest *** was estimated and taxonomic diversity,community weighted average(CWM)and functional divergence indices were *** found that the aerial biomass was significantly higher in the intensively used area(14.57(±1.60)t/hm^(2))than in the protected area(8.70(±1.05)t/hm^(2))due to persistence of some large trees but with decreasing values along the dieback intensity gradient in both *** of height(H),leaf nitrogen content(LNC)and leaf dry matter content(LDMC)were also higher in the traditional managed area than in the protected *** contrast,in the protected area,the woody species diversity was higher and the inter-specific competition was more intense,explaining a reduced H,biomass and *** to the results of CWM,none of the functional diversity traits(FDvar)was affected by dieback intensity and only FDvar values of LNC,leaf phosphorus content(LPC)and LDMC were influenced by *** also found significantly positive linear relationships of AGB with CWM and FDvar indices in the protected area,and with taxonomic and structural diversity indices in the traditional managed *** results emphasize that along a dieback intensity gradient,the leaf functional traits are efficient predictors in estimating the AGB in protected forests,while taxonomic and structural indices provide bett

关键词： environmental stress sudden oak dieback degradation conservation selection effect hypothesis

Fruits and Vegetables Freshness Categorization Using Deep Learning

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Computers, Materials & Continua 2022年第6期71卷 5083-5098页

作者： Labiba Gillani Fahad Syed Fahad Tahir Usama Rasheed Hafsa Saqib mehdi Hassan Hani Alquhayz Department of Computer Science National University of Computer and Emerging SciencesIslamabad44000Pakistan Department of Computer Science Air UniversityIslamabad44000Pakistan Department of Computer Science and Information College of Science in ZulfiMajmaah UniversityAl-Majmaah11952Kingdom of Saudi Arabia

The nutritional value of perishable food items,such as fruits and vegetables,depends on their freshness *** existing approaches solve a binary class problem by classifying a known fruit\vegetable class into fresh or rotten *** propose an automated fruits and vegetables categorization approach that first recognizes the class of object in an image and then categorizes that fruit or vegetable into one of the three categories:purefresh,medium-fresh,and *** gathered a dataset comprising of 60K images of 11 fruits and vegetables,each is further divided into three categories of freshness,using hand-held *** recognition and categorization of fruits and vegetables are performed through two deep learning models:Visual Geometry Group(VGG-16)and You Only Look Once(YOLO),and their results are ***-16 classifies fruits and vegetables and categorizes their freshness,while YOLO also localizes them within the ***,we have developed an android based application that takes the image of the fruit or vegetable as input and returns its class label and its freshness degree.A comprehensive experimental evaluation of proposed approach demonstrates that the proposed approach can achieve a high accuracy and F1score on gathered FruitVeg Freshness *** dataset is publicly available for further evaluation by the research community.

关键词： Fruits and vegetables classification degree of freshness deep learning object detection model VGG-16 YOLO-v5

Simultaneous multiple time scale imaging for kHz-MHz high-speed accelerometry

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Photonics Research 2022年第7期10卷 1712-1722页

作者： VASSILY KORNIENKO DAVID ANDERSSON mehdi STITI JONAS RAVELID SIMON EK ANDREAS EHN EDOUARD BERROCAL ELIAS KRISTENSSON Division of Combustion Physics Department of PhysicsLund UniversityLundSweden

Fast transient events,such as the disintegration of liquid bodies or chemical reactions between radical species,involve various processes that may occur at different time ***,there are two alternatives for monitoring such events:burst-or high-speed *** imaging at ultrahigh speeds(~100 MHz to THz)allows for the capture of nature's fastest processes but only for a narrowly confined period of time and at a repetition rate of~10 *** long lasting,rapidly evolving transient events requires a significantly higher repetition rate,which is met by existing~kHz to 1 MHz high-speed imaging ***,the use of such systems eliminates the possibility to observe dynamics occurring on the sub-microsecond time *** this paper,we present a solution to this technological gap by combining multiplexed imaging with high-speed sensor technology,resulting in temporally resolved,high-spatial-resolution image series at two simultaneous time *** further demonstrate how the collection of such data opens up the tracking of rapidly evolving structures up to MHz burst rates over long durations,allowing,for the first time,to our knowledge,the extraction of acceleration fields acting upon the liquid bodies of an atomizing spray in two dimensions at k Hz frame rates.

关键词： repetition high transient

Human reliability analysis in maintenance team of power transmission system protection

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Protection and Control of Modern Power Systems 2020年第1期5卷 290-302页

作者： mehdi Tavakoli mehdi Nafar Department of Electrical Engineering Marvdasht BranchIslamic Azad UniversityMarvdashtIran

The requirement for reliable electrical energy supply increases continuously because of its vital role in our ***,events due to various factors in the power grid can cause energy supply to be *** of these factors is human error and thus human reliability analysis is a serious element in the *** first step is to identify the roots of human error,on which there has been limited research in this *** this paper,the potential and actual causes of human error in maintenance teams of power transmission system protection are identified and predicted within a framework of human factors analysis and classification system ***,human error factors are ranked to help improve human *** proposed method is implemented in the Fars Electricity Maintenance Company.

关键词： Power transmission system protection Maintenance teams Human reliability HFACS method

Movement of Intransitive Permutation Groups Having Maximum Degree

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Chinese Annals of Mathematics,Series B 2012年第1期33卷 143-148页

作者： mehdi ALAEIYAN mehdi REZAEI School of Mathematics Iran University of Science and Technology

Let G be a permutation group on a set Ω with no fixed points in,and m be a positive *** the movement of G is defined as move(G):=sup Γ {|Γg\Γ| | g ∈ G}.It was shown by Praeger that if move(G) = m,then |Ω| 3m + t-1,where t is the number of G-orbits *** this paper,all intransitive permutation groups with degree 3m+t-1 which have maximum bound are ***,a positive answer to her question that whether the upper bound |Ω| = 3m + t-1 for |Ω| is sharp for every t > 1 is given.

关键词：置换群运动正整数固定点出版社 tgt 移动