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Information Processing in Agriculture 2019年第1期6卷 20-25页

作者： Alireza Sanaeifar abdolabbas jafari Department of Biosystems Engineering Shiraz UniversityShirazIran Lincoln Agritech Ltd. Lincoln UniversityLincolnNew Zealand

During storage,olive oil may suffer degradation leading to an inferior quality level when purchased and *** stability is one of the most important parameters for maintaining the quality of olive oil,which affects its acceptability and market *** current methods of predicting the oxidative stability of edible oils are costly and *** aim of the present research is to demonstrate the use of dielectric spectroscopy integrated with computer vision for determining the oxidative stability index(OSI)of olive *** most effective features were selected from the extracted dielectric and visual features for each olive oil *** machine learning techniques were employed to process the raw data to develop an oxidative stability prediction algorithm,including artificial neural network(ANN),support vector machine(SVM)and multiple linear regression(MLR).The predictive models showed a great agreement with the results obtained by the Rancimat instrument that was used as a reference *** best result for modelling the oxidative stability of olive oil was obtained using SVM technique with the R-value of *** can be concluded that this new approach may be utilized as a perfect replacement for quicker and cheaper assessment of olive oil oxidation.

关键词： Computer vision Dielectric spectroscopy Olive oil Oxidative stability index

Fuzzy logic classification of mature tomatoes based on physical properties fusion

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Information Processing in Agriculture 2022年第4期9卷 547-555页

作者： Seyed Mehdi Nassiri Amir Tahavoor abdolabbas jafari Department of Biosystems Engineering Shiraz UniversityShiraz 71441Iran Lincoln Agritech Ltd. Lincoln UniversityLincoln 7616New Zealand

Grading of fruits and vegetables is an initial step after *** is also an essential operation before *** the present study,different fuzzy algorithms for classifica-tion of mature tomato were applied and evaluated based on combinations of fruit color,size and *** membership functions of hardness were established by subject-ing samples to Instron compression test as well as the rates of *** sample was also used for image processing to determine the color and size of fruit using Matlab image processing *** and size fuzzy membership functions were established by pub-lished *** fuzzy If-Then rules were applied to classify the samples within five group outputs viz.“grade I”,“grade II”,“grade I-far market”,“processing”,and“storage”.Eighty-one fuzzy rules were reduced to 25 rules by combining the compatible *** fuzzy algorithms with different fuzzifiers(zmf,sigmf,gbellmf)and defuzzifiers(bisector,mom,and centroid)were applied,and the outputs were compared to the panelists’classi-fications in cross *** to the classification results,fuzzy algorithms grouped the fruits into correct classes with 90.9%,92.3%,88.7%,87.4%,92.4%and 93.3%accuracy for 6 models,*** best result was observed with zmf and sigmf,and gbellmf as fuzzifier and mom as defuzzifier with 93.3%***,the results revealed that the fusion of aforementioned tomato properties based on fuzzy membership functions could accurately classify the tomatoes in correct groups for different markets.

关键词： Fuzzy logic Grading Hardness Tomato Sorting

Non-harmonic resonance of viscoelastic structures subjected to time-dependent exponentially decreasing transverse distributed loads

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 825-840页

作者： Nasrin jafari Department of Civil Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran

In this paper,the non-harmonic resonance of Bernoulli viscoelastic beams,Kirchhoff viscoelastic plates,Timoshenko viscoelastic beams,and Mindlin viscoelastic plates subjected to time-dependent exponentially decreasing transverse distributed load is investigated for the first *** constitutive equations are expressed utilizing Boltzmann integral law with a constant bulk *** displacement vector is approximated by employing the separation of variables *** Laplace transformation is used to transfer equations from the time domain to the Laplace domain and vice *** novel point of the proposed method is to express,prove and calculate the critical time in which the displacement will be several times the displacement at time *** addition,this new method calculates the maximum deflection at the critical time,explicitly and exactly,without any need to follow the time-displacement curve with a low computational ***,the proposed method introduces the critical range of time so that the responses are greater than the responses at time zero.

关键词： Bernoulli and Timoshenko viscoelastic beams critical time non-harmonic resonance time-dependent decreasing exponential load Kirchhoff and Mindlin viscoelastic plates

Corrosion Behaviors of Two Types of Commercial Stainless Steel after Plastic Deformation

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Journal of Materials Science & Technology 2010年第9期26卷 833-838页

作者： Esmaeil jafari Materials Science and Engineering Department Islamic Azad University Shiraz Branch

The influence of deformation temperature,strain rate and alloying elements such as chromium,nickel,copper,on corrosion resistance of a 304 stainless steel after plastic deformation was *** techniques employed were tensile test at room and elevated temperature,deep drawing tests at various strain rates,X-ray diffraction test and potentiodynamic and cyclic polarization,metallography by optical and scanning electron *** showed that chromium,nickel and copper had a significant effect on corrosion resistance of steel after plastic *** was observed that corrosion resistance after plastic deformation was a function of deformation temperature and alloying elements.

关键词： Corrosion resistance Plastic deformation Stainless steel Phase transformation Polarization test

Cross-focusing of two chirped Gaussian laser beams and THz wave generation in plasmas of multi-ion species under a weakly relativistic and ponderomotive regime

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Plasma Science and Technology 2022年第10期24卷 1-11页

作者： M R jafari MILANI S REZAEI M J jafari Photonics and Quantum Technologies Research School Nuclear Science and Technology Research InstituteTehran 14665-678Iran Plasma and Fusion Research School Nuclear Science and Technology Research InstituteTehran 14399-51113Iran

The generation of terahertz(THz)waves via the beating of two high-intensity chirped Gaussian lasers in a multi-ion-species plasma is numerically studied by taking into account the weak relativistic and ponderomotive regime of *** coupled differential equations for beamwidth parameters are extracted by introducing the dielectric function of such plasma and using WKB and paraxial ray *** amplitude of THz radiation at beat frequency resulting from the nonlinear current density induced by the beat ponderomotive force of the cross-focusing of beams was *** impacts of the chirp frequency parameter,initial laser intensity and initial ionic species density(specifically,the presence of singly and doubly charged ions)in the plasma on THz generation were *** numerical results reveal that THz radiation generation strongly depends on the chirp frequency parameter.A specific range of chirp frequencies exists for self-focusing as well as THz generation with a'turning point',where the THz emission reaches its maximum *** results show that the strength of self-focusing and consequently the generated THz radiation are reduced by increasing the density of doubly charged ionic species in the plasma due to the suppression of the nonlinear effects.

关键词： laser–plasma interaction THz generation chirped Gaussian laser beams

Introducing the general condition for an operator in curved space to be unitary

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Chinese Physics B 2021年第8期30卷 220-223页

作者： jafari Matehkolaee Mehdi Faculty of Physics Semnan UniversitySemnan35131-19111Iran

We investigate the general condition for an operator to be *** condition is introduced according to the definition of the position operator in curved *** a particular case,we discuss the concept of translation operator in curved space followed by its relation with an anti-Hermitian *** we introduce a universal formula for adjoint of an arbitrary linear *** procedure in this paper is totally different from others,as we explore a general approach based only on the algebra of the *** approach is only discussed for the translation operators in one-dimensional space and not for general operators.

关键词： operator theory algebraic methods unitary operator translation operator

Data driven models for compressive strength prediction of concrete at high temperatures

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 311-321页

作者： Mahmood AKBARI Vahid jafari DELIGANI Department of Civil Engineering Faculty of EngineeringUniversity of KashanKashan ***Iran

The use of data driven models has been shown to be useful for simulating complex engineering processes,when the only information available consists of the data of the *** this study,four data-driven models,namely multiple linear regression,artificial neural network,adaptive neural fuzzy inference system,and K nearest neighbor models based on collection of 207 laboratory tests,are investigated for compressive strength prediction of concrete at high *** addition for each model,two different sets of input variables are examined:a complete set and a parsimonious set of involved *** results obtained are compared with each other and also to the equations of NIST Technical Note standard and demonstrate the suitability of using the data driven models to predict the compressive strength at high *** addition,the results show employing the parsimonious set of input variables is sufficient for the data driven models to make satisfactory results.

关键词： data driven model compressive strength oncrete high temperature

Investigation of parameters influencing erosive wear using DEM

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Friction 2020年第1期8卷 136-150页

作者： Akbar jafari Reza ABBASI HATTANI Department of Mechanical Engineering Sirjan University of TechnologySirjan ***Iran

The effects of several parameters on the erosive wear were studied using the discrete element method(DEM).The Finnie model was implemented using an open‐source *** the time integration,the Gear algorithm was used,and to ensure the accuracy of the DEM results,a time‐step sensitivity analysis was *** problem was modeled in two parts:first,the impact of a single particle on a surface was modeled,and then a more general model was prepared to examine the wear of surfaces under the flow of *** effects of the surface area,impact angle,speed,particle size,particle density,Young’s modulus,Poisson’s ratio,and restitution coefficient on the wear were studied numerically,and the results are discussed herein.

关键词： wear erosion Finnie discrete element

Serendipity in Recommender Systems:A Systematic Literature Review

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Journal of Computer Science & Technology 2021年第2期36卷 375-396页

作者： Reza jafari Ziarani Reza Ravanmehr Department of Computer Engineering Central Tehran BranchIslamic Azad UniversityTehran ***Iran

A recommender system is employed to accurately recommend items,which are expected to attract the user's *** over-emphasis on the accuracy of the recommendations can cause information over-specialization and make recommendations boring and even *** and diversity are two partly useful solutions to these ***,novel and diverse recommendations cannot merely ensure that users are attracted since such recommendations may not be relevant to the user's ***,it is necessary to consider other criteria,such as unexpectedness and *** is a criterion for making appealing and useful *** usefulness of serendipitous recommendations is the main superiority of this criterion over novelty and *** bulk of studies of recommender systems have focused on serendipity in recent ***,a systematic literature review is conducted in this paper on previous studies of serendipity-oriented recommender ***,this paper focuses on the contextual convergence of serendipity definitions,datasets,serendipitous recommendation methods,and their evaluation ***,the trends and existing potentials of the serendipity-oriented recommender systems are discussed for future *** results of the systematic literature review present that the quality and the quantity of articles in the serendipity-oriented recommender systems are progressing.

关键词： systematic literature review recommender system serendipity evaluation metric evaluation method

Experimental study and a proposed new approach for thermodynamic modeling of wax precipitation in crude oil using a PC-SAFT model

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Petroleum Science 2016年第1期13卷 155-166页

作者： Taraneh jafari Behbahani Research Institute of Petroleum Industry (RIPI) P.O.Box 14665-1998 Tehran Iran

A powerful method is necessary for thermodynamic modeling of wax phase behavior in crude oils,such as the perturbed-chain statistical associating fluid theory（PC-SAFT）.In this work,a new approach based on the wax appearance temperature of crude oil was proposed to estimate PC-SAFT parameters in thermodynamic modeling of wax precipitation from crude *** proposed approach was verified using experimental data obtained in this work and also with those reported in the *** order to compare the performance of the PC-SAFT model with previous models,the wax precipitation experimental data were correlated using previous models such as the solid solution model and multi-solid phase *** results showed that the PC-SAFT model can correlate more accurately the wax precipitation experimental data of crude oil than the previous models,with an absolute average deviation less than 0.4 %.Also,a series of dynamic experiments were carried out to determine the rheological behavior of waxy crude oil in the absence and presence of a flow improver such as ethylene–vinyl acetate *** was found that the apparent viscosity of waxy crude oil decreased with increasing shear ***,the results showed that the performance of flow improver was dependent on its molecular weight.

关键词： crude deviation thermodynamic viscosity copolymer appearance rheological hydrocarbons verified powerful