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    Lifetable analysis of Spodoptera exigua Hübner on alternate hosts from cotton agroecosystem for estimating annual population build-up

    , Article International Journal of Pest Management ; Volume 67, Issue 3 , 2021 , Pages 252-259 ; 09670874 (ISSN) Ahmad, F ; Saeed, S ; Chen, T ; Saeed, Q ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    Understanding the population growth patterns of Spodoptera exigua on alternate host plants can provide valuable information for developing an effective pest management program. In this study, using age-specific lifetable indices, we evaluated the role of alternate crops commonly found in cotton agroecosystem of Pakistan to better understand population dynamics of S. exigua. The longest larval and pupal periods (16.35 and 9.95days, respectively) were observed on spinach, while the shortest periods were recorded on okra (13 days) and cauliflower (8.4 days), respectively. Relatively more female moths (61%) were produced on spinach with low rm (0.095) and λ (1.0997) while highest rm (0.120) and... 

    Lifetable analysis of Spodoptera exigua Hübner on alternate hosts from cotton agroecosystem for estimating annual population build-up

    , Article International Journal of Pest Management ; Volume 67, Issue 3 , 2021 , Pages 252-259 ; 09670874 (ISSN) Ahmad, F ; Saeed, S ; Chen, T ; Saeed, Q ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    Understanding the population growth patterns of Spodoptera exigua on alternate host plants can provide valuable information for developing an effective pest management program. In this study, using age-specific lifetable indices, we evaluated the role of alternate crops commonly found in cotton agroecosystem of Pakistan to better understand population dynamics of S. exigua. The longest larval and pupal periods (16.35 and 9.95days, respectively) were observed on spinach, while the shortest periods were recorded on okra (13 days) and cauliflower (8.4 days), respectively. Relatively more female moths (61%) were produced on spinach with low rm (0.095) and λ (1.0997) while highest rm (0.120) and... 

    PRI (Palm Rotation Indicator): a metric for postural stability in dynamic nonprehensile manipulation [electronic resource]

    , Article Journal of MECHANIKA ; 2012, Vol. 18, No. 4, pp. 461-466 Beigzadeh, B. (Borhan) ; Meghdar, Ali ; Sohrabpour, Saeed ; Sharif University of Technology
    Abstract
    In this study, we discuss the postural stability of a nonprehensile manipulation problem, which deals with multibody objects. As a metric for postural stability, we define PRI. Then, the system is posturally stable, if PRI is inside the convex hull of the object-manipulator contact surface. We then discuss that dynamic biped locomotion is a special case of dynamic nonprehensile manipulation in all aspects; we prove that ZMP (zero-moment point) and FRI (zoot rotation indicator) are special cases of PRI (palm rotation indicator). Simulations and experiments corresponding to simple examples support the results  

    Photocatalytic mechanism of action of apatite-coated Ag=AgBr=TiO 2 on phenol and Escherichia coli and Bacillus subtilis bacteria under various conditions

    , Article Progress in Reaction Kinetics and Mechanism ; Vol. 1 , Vol.36 (1) , 2011 , pp.38-52 Elahifard, M. R. (Mohammad Reza) ; Gholami, M. R. (Mohammad Reza) ; Rahimnejad, S. (Sara) ; Pourbaba, R. (Reza) ; Haghighi, S.(Saeed) ; Sharif University Of Technology
    2011
    Abstract
    Multi-component photocatalysts based on apatite-coated Ag/AgBr/TiO(2) were prepared by the deposition method. The effects of various kinds of apatites, with hydroxyl and fluoro substituents, on photocatalytic activity were investigated. The antibacterial processes in the dark, and under visible light, on two types of bacteria indicate that the multi-composites can inhibit the growth of bacteria by two different mechanisms. TEM images and optical microscopic data demonstrate that by attaching the nanosize catalyst to the outer membrane of the cell, the bacteria could not derive nourishment from surrounding media, i.e. this component acts as bacteria-static. The mechanism for deactivation of... 

    Measuring routine childhood vaccination coverage in 204 countries and territories, 1980–2019: a systematic analysis for the Global Burden of Disease Study 2020, Release 1

    , Article The Lancet ; Volume 398, Issue 10299 , 2021 , Pages 503-521 ; 01406736 (ISSN) Galles, N. C ; Liu, P.Y ; Updike, R.L ; Fullman, N ; Nguyen, J ; Rolfe, S ; Sbarra, A.N ; Schipp, M.F ; Marks, A ; Abady, G.G ; Abbas, K.M ; Abbasi, S.W ; Abbastabar, H ; Abd-Allah, F ; Abdoli, A ; Abolhassani, H ; Abosetugn, A.E ; Adabi, M ; Adamu, A.A ; Adetokunboh, O.O ; Adnani, Q.E.S ; Advani, S.M ; Afzal, S ; Aghamir, S.M.K ; Ahinkorah, B.O ; Ahmad, S ; Ahmad, T ; Ahmadi, S ; Ahmed, H ; Ahmed, M.B ; Ahmed Rashid, T ; Ahmed Salih, Y ; Akalu, Y ; Aklilu, A ; Akunna, C.J ; Al Hamad, H ; Alahdab, F ; Albano, L ; Alemayehu, Y ; Alene, K.A ; Al-Eyadhy, A ; Alhassan, R.K ; Ali, L ; Aljunid, S.M ; Almustanyir, S ; Altirkawi, K.A ; Alvis-Guzman, N ; Amu, H ; Andrei, C.L ; Andrei, T ; Ansar, A ; Ansari-Moghaddam, A ; Antonazzo, I.C ; Antony, B ; Arabloo, J ; Arab-Zozani, M ; Artanti, K.D ; Arulappan, J ; Awan, A.T ; Awoke, M.A ; Ayza, M.A ; Azarian, G ; Azzam, A.Y ; B, D.B ; Babar, Z.-U.-D ; Balakrishnan, S ; Banach, M ; Bante, S.A ; Bärnighausen, T.W ; Barqawi, H.J ; Barrow, A ; Bassat, Q ; Bayarmagnai, N ; Bejarano Ramirez, D.F ; Bekuma, T.T ; Belay, H.G ; Belgaumi, U.I ; Bhagavathula, A.S ; Bhandari, D ; Bhardwaj, N ; Bhardwaj, P ; Bhaskar, S ; Bhattacharyya, K ; Bibi, S ; Bijani, A ; Biondi, A ; Boloor, A ; Braithwaite, D ; Buonsenso, D ; Butt, Z.A ; Camargos, P ; Carreras, G ; Carvalho, F ; Castañeda-Orjuela, C.A ; Chakinala, R.C ; Charan, J ; Chatterjee, S ; Chattu, S.K ; Chattu, V.K ; Chowdhury, F.R ; Christopher, D.J ; Chu, D.-T ; Chung, S.-C ; Cortesi, P.A ; Costa, V.M ; Couto, R.A.S ; Dadras, O ; Dagnew, A.B ; Dagnew, B ; Dai, X ; Dandona, L ; Dandona, R ; De Neve, J.-W ; Derbew Molla, M ; Derseh, B.T ; Desai, R ; Desta, A.A ; Dhamnetiya, D ; Dhimal, M.L ; Dhimal, M ; Dianatinasab, M ; Diaz, D ; Djalalinia, S ; Dorostkar, F ; Edem, B ; Edinur, H.A ; Eftekharzadeh, S ; El Sayed, I ; El Sayed Zaki, M ; Elhadi, M ; El-Jaafary, S.I ; Elsharkawy, A ; Enany, S ; Erkhembayar, R ; Esezobor, C.I ; Eskandarieh, S ; Ezeonwumelu, I.J ; Ezzikouri, S ; Fares, J ; Faris, P.S ; Feleke, B.E ; Ferede, T.Y ; Fernandes, E ; Fernandes, J.C ; Ferrara, P ; Filip, I ; Fischer, F ; Francis, M.R ; Fukumoto, T ; Gad, M.M ; Gaidhane, S ; Gallus, S ; Garg, T ; Geberemariyam, B.S ; Gebre, T ; Gebregiorgis, B.G ; Gebremedhin, K.B ; Gebremichael, B ; Gessner, B.D ; Ghadiri, K ; Ghafourifard, M ; Ghashghaee, A ; Gilani, S.A ; Glăvan, I.-R ; Glushkova, E.V ; Golechha, M ; Gonfa, K.B ; Gopalani, S.V ; Goudarzi, H ; Gubari, M.I.M ; Guo, Y ; Gupta, V.B ; Gupta, V.K ; Gutiérrez, R.A ; Haeuser, E ; Halwani, R ; Hamidi, S ; Hanif, A ; Haque, S ; Harapan, H ; Hargono, A ; Hashi, A ; Hassan, S ; Hassanein, M.H ; Hassanipour, S ; Hassankhani, H ; Hay, S.I ; Hayat, K ; Hegazy, M.I ; Heidari, G ; Hezam, K ; Holla, R ; Hoque, M.E ; Hosseini, M ; Hosseinzadeh, M ; Hostiuc, M ; Househ, M ; Hsieh, V.C.-R ; Huang, J ; Humayun, A ; Hussain, R ; Hussein, N.R ; Ibitoye, S.E ; Ilesanmi, O.S ; Ilic, I.M ; Ilic, M.D ; Inamdar, S ; Iqbal, U ; Irham, L.M ; Irvani, S.S.N ; Islam, S.M.S ; Ismail, N.E ; Itumalla, R ; Jha, R.P ; Joukar, F ; Kabir, A ; Kabir, Z ; Kalhor, R ; Kamal, Z ; Kamande, S.M ; Kandel, H ; Karch, A ; Kassahun, G ; Kassebaum, N.J ; Katoto, P.D ; Kelkay, B ; Kengne, A.P ; Khader, Y.S ; Khajuria, H ; Khalil, I.A ; Khan, E.A ; Khan, G ; Khan, J ; Khan, M.A ; Khan, M.A ; Khang, Y.-H ; Khoja, A.T ; Khubchandani, J ; Kim, G.R ; Kim, M.S ; Kim, Y.J ; Kimokoti, R.W ; Kisa, A ; Kisa, S ; Korshunov, V.A ; Kosen, S ; Kuate Defo, B ; Kulkarni, V ; Kumar, A ; Kumar, G.A ; Kumar, N ; Kwarteng, A ; La Vecchia, C ; Lami, F.H ; Landires, I ; Lasrado, S ; Lassi, Z.S ; Lee, H ; Lee, Y.Y ; Levi, M ; Lewycka, S ; Li, S ; Liu, X ; Lobo, S.W ; Lopukhov, P.D ; Lozano, R ; Lutzky Saute, R ; Magdy Abd El Razek, M ; Makki, A ; Malik, A.A ; Mansour-Ghanaei, F ; Mansournia, M.A ; Mantovani, L.G ; Martins-Melo, F.R ; Matthews, P.C ; Medina, J.R.C ; Mendoza, W ; Menezes, R.G ; Mengesha, E.W ; Meretoja, T.J ; Mersha, A.G ; Mesregah, M.K ; Mestrovic, T ; Miazgowski, B ; Milne, G.J ; Mirica, A ; Mirrakhimov, E.M ; Mirzaei, H.R ; Misra, S ; Mithra, P ; Moghadaszadeh, M ; Mohamed, T.A ; Mohammad, K.A ; Mohammad, Y ; Mohammadi, M ; Mohammadian-Hafshejani, A ; Mohammed, A ; Mohammed, S ; Mohapatra, A ; Mokdad, A.H ; Molokhia, M ; Monasta, L ; Moni, M.A ; Montasir, A.A ; Moore, C.E ; Moradi, G ; Moradzadeh, R ; Moraga, P ; Mueller, U.O ; Munro, S.B ; Naghavi, M ; Naimzada, M.D ; Naveed, M ; Nayak, B.P ; Negoi, I ; Neupane Kandel, S ; Nguyen, T.H ; Nikbakhsh, R ; Ningrum, D.N.A ; Nixon, M.R ; Nnaji, C.A ; Noubiap, J.J ; Nuñez-Samudio, V ; Nwatah, V.E ; Oancea, B ; Ochir, C ; Ogbo, F.A ; Olagunju, A.T ; Olakunde, B.O ; Onwujekwe, O.E ; Otstavnov, N ; Otstavnov, S.S ; Owolabi, M.O ; Padubidri, J.R ; Pakshir, K ; Park, E.-C ; Pashazadeh Kan, F ; Pathak, M ; Paudel, R ; Pawar, S ; Pereira, J ; Peres, M.F.P ; Perianayagam, A ; Pinheiro, M ; Pirestani, M ; Podder, V ; Polibin, R.V ; Pollok, R.C.G ; Postma, M.J ; Pottoo, F.H ; Rabiee, M ; Rabiee, N ; Radfar, A ; Rafiei, A ; Rahimi-Movaghar, V ; Rahman, M ; Rahmani, A.M ; Rahmawaty, S ; Rajesh, A ; Ramshaw, R.E ; Ranasinghe, P ; Rao, C.R ; Rao, S.J ; Rathi, P ; Rawaf, D.L ; Rawaf, S ; Renzaho, A.M.N ; Rezaei, N ; Rezai, M.S ; Rios-Blancas, M ; Rogowski, E.L.B ; Ronfani, L ; Rwegerera, G.M ; Saad, A.M ; Sabour, S ; Saddik, B ; Saeb, M.R ; Saeed, U ; Sahebkar, A ; Sahraian, M.A ; Salam, N ; Salimzadeh, H ; Samaei, M ; Samy, A.M ; Sanabria, J ; Sanmarchi, F ; Santric-Milicevic, M.M ; Sartorius, B ; Sarveazad, A ; Sathian, B ; Sawhney, M ; Saxena, D ; Saxena, S ; Seidu, A.-A ; Seylani, A ; Shaikh, M.A ; Shamsizadeh, M ; Shetty, P.H ; Shigematsu, M ; Shin, J.I ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Background: Measuring routine childhood vaccination is crucial to inform global vaccine policies and programme implementation, and to track progress towards targets set by the Global Vaccine Action Plan (GVAP) and Immunization Agenda 2030. Robust estimates of routine vaccine coverage are needed to identify past successes and persistent vulnerabilities. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020, Release 1, we did a systematic analysis of global, regional, and national vaccine coverage trends using a statistical framework, by vaccine and over time. Methods: For this analysis we collated 55 326 country-specific, cohort-specific, year-specific,... 

    A Bayesian-reliability based multi-objective optimization for tolerance design of mechanical assemblies

    , Article Reliability Engineering and System Safety ; Volume 213 , 2021 ; 09518320 (ISSN) Ghaderi, A ; Hassani, H ; Khodaygan, S ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Tolerances significantly affect the assemblability of components, the product's performance, and manufacturing cost in mechanical assemblies. Despite the importance of product reliability assessment, the reliability-based tolerance design of mechanical assemblies has not been previously considered in the literature. In this paper, a novel method based on Bayesian modeling is proposed for the tolerance-reliability analysis and allocation of complex assemblies where the explicit assembly functions are difficult or impossible to extract. To reach this aim, a Bayesian model is developed for tolerance-reliability analysis. Then, a multi-objective optimization formulation is proposed for obtaining... 

    Prioritizing adoption barriers of platforms based on blockchain technology from balanced scorecard perspectives in healthcare industry: a structural approach

    , Article International Journal of Production Research ; 2022 ; 00207543 (ISSN) Govindan, K ; Nasr, A. K ; Saeed Heidary, M ; Nosrati-Abargooee, S ; Mina, H ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    Since the advent of blockchain technology (BT), extensive research has explored using this technology in non-financial cases. The healthcare industry is one of the non-financial sectors that BT has significantly impacted. In this paper, for the first time, barriers to implement BT-based platforms from a balanced scorecard perspective in the healthcare sector are introduced, and these barriers are prioritized using a structural approach based on the weighted influence non-linear gauge system. Unlike other structural models such as decision-making trial and evaluation laboratory (DEMATEL), in this approach, both strength and influence intensity of components are considered in the ranking... 

    Hearing loss prevalence and years lived with disability, 1990-2019: Findings from the Global Burden of Disease Study 2019

    , Article The Lancet ; Volume 397, Issue 10278 , 2021 , Pages 996-1009 ; 01406736 (ISSN) Haile, L. M ; Kamenov, K ; Briant, P. S ; Orji, A. U ; Steinmetz, J. D ; Abdoli, A ; Abdollahi, M ; Abu-Gharbieh, E ; Afshin, A ; Ahmed, H ; Rashid, T. A ; Akalu, Y ; Alahdab, F ; Alanezi, F. M ; Alanzi, T. M ; Al Hamad, H ; Ali, L ; Alipour, V ; Al-Raddadi, R. M ; Amu, H ; Arabloo, J ; Arab-Zozani, M ; Arulappan, J ; Ashbaugh, C ; Atnafu, D. D ; Babar, Z. U. D ; Baig, A. A ; Banik, P. C ; Bärnighausen, T. W ; Barrow, A ; Bender, R. G ; Bhagavathula, A. S ; Bhardwaj, N ; Bhardwaj, P ; Bibi, S ; Bijani, A ; Burkart, K ; Cederroth, C. R ; Charan, J ; Choudhari, S. G ; Chu, D. T ; Couto, R. A. S ; Dagnew, A. B ; Dagnew, B ; Dahlawi, S. M. A ; Dai, X ; Dandona, L ; Dandona, R ; Desalew, A ; Dhamnetiya, D ; Dhimal, M. L ; Dhimal, M ; Doyle, K. E ; Duncan, B. B ; Ekholuenetale, M ; Filip, I ; Fischer, F ; Franklin, R. C ; Gaidhane, A. M ; Gaidhane, S ; Gallus, S ; Ghamari, F ; Ghashghaee, A ; Ghozali, G ; Gilani, S.A ; Glǎvan, I. R ; Golechha, M ; Goulart, B. N. G ; Gupta, V. B ; Gupta, V. K ; Hamidi, S ; Hammond, B. R ; Hay, S. I ; Hayat, K ; Heidari, G ; Hoffman, H. J ; Hopf, K. P ; Hosseinzadeh, M ; Househ, M ; Hussain, R ; Hwang, B. F ; Iavicoli, I ; Ibitoye, S. E ; Ilesanmi, O. S ; Irvani, S. S. N ; Islam, S. M. S ; Iwagami, M ; Jacob, L ; Jayapal, S. K ; Jha, R. P ; Jonas, J. B ; Kalhor, R ; Al-Salihi, N. K ; Kandel, H ; Kasa, A. S ; Kayode, G. A ; Khalilov, R ; Khan, E. A ; Khatib, M. N ; Kosen, S ; Koyanagi, A ; Kumar, G. A ; Landires, I ; Lasrado, S ; Lim, S. S ; Liu, X ; Lobo, S. W ; Lugo, A ; Makki, A ; Mendoza, W ; Mersha, A. G ; Mihretie, K. M ; Miller, T. R ; Misra, S ; Mohamed, T. A ; Mohammadi, M ; Mohammadian Hafshejani, A ; Mohammed, A ; Mokdad, A. H ; Moni, M. A ; Kandel, S. N ; Nguyen, H. L. T ; Nixon, M. R ; Noubiap, J. J ; Nuñez Samudio, V ; Oancea, B ; Oguoma, V. M ; Olagunju, A. T ; Olusanya, B. O ; Olusanya, J. O ; Orru, H ; Owolabi, M. O ; Padubidri, J. R ; Pakshir, K ; Pardhan, S ; Kan, F. P ; Pasovic, M ; Pawar, S ; Pham, H. Q ; Pinheiro, M ; Pourshams, A ; Rabiee, N ; Rabiee, M ; Radfar, A ; Rahim, F ; Rahimi Movaghar, V ; Ur Rahman, M. H ; Rahman, M ; Rahmani, A. M ; Rana, J ; Rao, C. R ; Rao, S. J ; Rashedi, V ; Rawaf, D. L ; Rawaf, S ; Renzaho, A. M. N ; Rezapour, A ; Ripon, R. K ; Rodrigues, V ; Rustagi, N ; Saeed, U ; Sahebkar, A ; Samy, A. M ; Santric-Milicevic, M. M ; Sathian, B ; Satpathy, M ; Sawhney, M ; Schlee, W ; Schmidt, M. I ; Seylani, A ; Shaikh, M. A ; Shannawaz, M ; Shiferaw, W. S ; Siabani, S ; Singal, A ; Singh, J. A ; Singh, J. K ; Singhal, D ; Skryabin, V. Y ; Skryabina, A. A ; Sotoudeh, H ; Spurlock, E. E ; Taddele, B. W ; Tamiru, A. T ; Tareque, M. I ; Thapar, R ; Tovani-Palone, M. R ; Tran, B.X ; Ullah, S ; Tahbaz, S. V ; Violante, F. S ; Vlassov, V ; Vo, B ; Vongpradith, A ; Vu, G. T ; Wei, J ; Yadollahpour, A ; Jabbari, S. H. Y ; Yeshaw, Y ; Yiǧit, V ; Yirdaw, B. W ; Yonemoto, N ; Yu, C ; Yunusa, I ; Zamani, M ; Zastrozhin, M. S ; Zastrozhina, A ; Zhang, Z. J ; Zhao, J. T ; Murray, C. J. L ; Davis, A. C ; Vos, T ; Chadha, S ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Background: Hearing loss affects access to spoken language, which can affect cognition and development, and can negatively affect social wellbeing. We present updated estimates from the Global Burden of Disease (GBD) study on the prevalence of hearing loss in 2019, as well as the condition's associated disability. Methods: We did systematic reviews of population-representative surveys on hearing loss prevalence from 1990 to 2019. We fitted nested meta-regression models for severity-specific prevalence, accounting for hearing aid coverage, cause, and the presence of tinnitus. We also forecasted the prevalence of hearing loss until 2050. Findings: An estimated 1·57 billion (95% uncertainty... 

    Implementing a high-order accurate implicit operator scheme for solving steady incompressible viscous flows using artificial compressibility method

    , Article International Journal for Numerical Methods in Fluids ; Volume 66, Issue 8 , July , 2011 , Pages 939-962 ; 02712091 (ISSN) Hejranfar, K ; Khajeh Saeed, A ; Sharif University of Technology
    2011
    Abstract
    This paper uses a fourth-order compact finite-difference scheme for solving steady incompressible flows. The high-order compact method applied is an alternating direction implicit operator scheme, which has been used by Ekaterinaris for computing two-dimensional compressible flows. Herein, this numerical scheme is efficiently implemented to solve the incompressible Navier-Stokes equations in the primitive variables formulation using the artificial compressibility method. For space discretizing the convective fluxes, fourth-order centered spatial accuracy of the implicit operators is efficiently obtained by performing compact space differentiation in which the method uses block-tridiagonal... 

    High-order accurate numerical solution of incompressible slip flow and heat transfer in microchannels

    , Article Lecture Notes in Computational Science and Engineering, 22 June 2009 through 26 June 2009 ; Volume 76 LNCSE , June , 2011 , Pages 419-427 ; 14397358 (ISSN); 9783642153365 (ISBN) Hejranfar, K ; Mohafez, M. H ; Khajeh Saeed, A ; Sharif University of Technology
    2011
    Abstract
    A high-order accurate implicit operator scheme is used to solve steady incompressible slip flow and heat transfer in 2D microchannels. The present methodology considers the solution of the Navier-Stokes equations using the artificial compressibility method with employing the Maxwell and Smoluchowski boundary conditions to model the slip flow and temperature jump on the walls in microchannels. Since the slip and temperature jump boundary conditions contain the derivatives of the velocity and temperature profiles, using the compact method the boundary conditions can be easily and accurately implemented. The computations are performed for a 2D microchannel and a 2D backward facing step in the... 

    A high-order accurate implicit operator scheme for solving steady incompressible viscous flows using artificial compressibility method

    , Article Computational Fluid Dynamics 2008 ; 2009 , Pages 141-145 Hejranfar, K ; Khajeh Saeed, A ; Sharif University of Technology
    Springer berlin  2009
    Abstract
    This paper uses a fourth-order compact implicit operator scheme for solving 2D/3D steady incompressible flows using the artificial compressibility method. To stabilize the numerical solution, numerical dissipation terms and/or filters are used. Results obtained for test cases are in good agreement with the available numerical and experimental results. A sensitivity study is also conducted to evaluate the effects of grid resolution and pseudocompressibility parameter on accuracy and convergence rate of the solution. The effects of filtering and numerical dissipation on the solution are also investigated  

    Prognostic of rolling element bearings based on early-stage developing faults

    , Article International Journal of COMADEM ; Volume 23, Issue 1 , February , 2020 , Pages 55-60 Hosseini Yazdi, M ; Behzad, M ; Ghodrati, B ; Khodaygan, S
    COMADEM International  2020
    Abstract
    Rolling-element bearing (REB) failure is one of the general damages in rotating machinery. In this manner, the correct prediction of remaining useful life (RUL) of REB is a crucial challenge to move forward the unwavering quality of the machines. One of the main difficulties in implementing data-driven methods for RUL prediction is to choose proper features that represent real damage progression. In this article, by using the outcomes of frequency analysis through the Envelope method, the initiated/existed defects on the ball bearings are identified. Also, new features based on developing faults of ball bearings is recommended to estimate RUL. Early-stage faults in ball bearings usually... 

    Prognostic of rolling element bearings based on early-stage developing faults

    , Article 2nd World Congress on Condition Monitoring, WCCM 2019, 2 December 2019 through 5 December 2019 ; 2021 , Pages 333-342 ; 21954356 (ISSN); 9789811591983 (ISBN) Hosseini Yazdi, M ; Behzad, M ; Khodaygan, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Rolling element bearing (REB) failure is one of the general damages in rotating machinery. In this manner, the correct prediction of remaining useful life (RUL) of REB is a crucial challenge to move forward the unwavering quality of the machines. One of the main difficulties in implementing data-driven methods for RUL prediction is to choose proper features that represent real damage progression. In this article, by using the outcomes of frequency analysis through the envelope method, the initiated/existed defects on the ball bearings are identified. Also, new features based on developing faults of ball bearings are recommended to estimate RUL. Early-stage faults in ball bearings usually... 

    Prediction of machining chatter in milling based on dynamic FEM simulations of chip formation

    , Article Advances in Manufacturing ; Volume 6, Issue 3 , 2018 , Pages 334-344 ; 20953127 (ISSN) Jafarzadeh, E ; Movahhedy, M. R ; Khodaygan, S ; Ghorbani, M ; Sharif University of Technology
    Shanghai University Press  2018
    Abstract
    Chatter vibration is a major obstacle in achieveing increased machining performance. In this research, a finite element model of chip formation in a 2D milling process is used to predict the occurrence of chatter vibrations, and to investigate the effects of various machining parameters on this phenomenon. The dynamic properties of the machine tool at the tool tip are obtained based on experimental modal analysis, and are used in the model as the cutter dynamics. The model allows for the natural development of vibration as the result of the chip-tool engagement, and accounts for various phenomena that occur at the chip-tool interface ultimately leading to stable or unstable cutting. The... 

    The first in situ synthesis of 1,3-dioxan-5-one derivatives and their direct use in Claisen-Schmidt reactions: Synthesis of dioxanones and their Claisen-Schmidt reactions

    , Article Heterocyclic Communications ; Volume 25, Issue 1 , 2019 , Pages 85-90 ; 07930283 (ISSN) Javad Poursharifi, M ; Mojtahedi, M. M ; Saeed Abaee, M ; Hashemi, M. M ; Sharif University of Technology
    De Gruyter  2019
    Abstract
    A method is developed for in situ generation of 1,3-dioxan-5-one derivatives 2. These compounds are simple precursors for accessing carbohydrate structures and previously had to be produced via stepwise procedures using excessive amounts of reagents. In the present work, three different derivatives of 2 were synthesized via the reaction of trialkoxyalkanes with dihydroxyacetone dimer 1 in the presence of acetic acid as the catalyst. In the same pot, derivatives of 2 were reacted with aromatic aldehydes and 30 mol% of pyrrolidine to obtain high yields of the respective bischalcones 3 within short time periods. © 2019 M. Javad Poursharifi et al., published by De Gruyter 2019  

    Robust tolerance design of mechanical assemblies using a multi-objective optimization formulation

    , Article SAE Technical Papers ; Vol. 1 , 2014 Khodaygan, S ; Movahhedy, M. R ; Sharif University of Technology
    2014
    Abstract
    The design process always has some known or unknown uncertainties in the design variables and parameters. The aim of robust design is minimization of performance sensitivity to uncertainties. Tolerance allocation process can significantly affect quality and robustness of the product. In this paper, a methodology to minimize a product's sensitivity to uncertainties by allocating manufacturing tolerances is presented. The robust tolerance design problem is formulated as a multi-objective optimization based on the combined function-uncertainty-cost model. Genetic algorithm is utilized to solve the multi-objective optimization and a case study is presented to illustrate the methodology  

    Manufacturing error compensation based on cutting tool location correction in machining processes

    , Article International Journal of Computer Integrated Manufacturing ; Vol. 27, Issue. 11 , 29 Oct , 2014 , pp. 969-978 ; ISSN: 0951192X Khodaygan, S ; Sharif University of Technology
    2014
    Abstract
    Inaccuracies in workpiece location lead to errors in position and orientation of machined features on the workpiece, and strongly affect the assemblability and the quality of the product. The accurate positioning of workpiece on a fixture is influenced by rigid body displacements and rotations of the workpiece due to several errors (e.g. geometric radial and position errors in locators and manufacturing tolerances of the workpiece). In this paper, an efficient approach is introduced for analysis and compensation errors in the workpiece-fixture-cutting tool system. A new mathematical formulation of workpiece-fixture modelling is proposed to establish the relationship between the locating... 

    Functional process capability analysis in mechanical systems

    , Article International Journal of Advanced Manufacturing Technology ; Vol. 73, issue. 5-8 , July , 2014 , p. 899-912 ; 02683768 Khodaygan, S ; Movahhedy, M. R ; Sharif University of Technology
    2014
    Abstract
    Functional quality in the mechanical products is governed mainly by the degree of satisfaction of the design requirements, which itself depends on the variations in the effective variables. The functional parameters cannot be easily measured in mass production, and thus, are not usually considered as a direct inspection objective. Process capability indices are useful tools for evaluating the ability of a process to produce the dependent variables of a product that meet certain specifications. In this paper, the conventional process capability concept is extended to develop a computational tool for analysis of the functional quality of a mechanical product. Through defining new proper... 

    Fuzzy-based analysis of process capability for assembly quality assessment in mechanical assemblies

    , Article International Journal of Production Research ; Volume 50, Issue 12 , 2012 , Pages 3395-3415 ; 00207543 (ISSN) Khodaygan, S ; Movahhedy, M. R ; Sharif University of Technology
    2012
    Abstract
    Process capability indices are useful tools for evaluating the ability of a process to produce products that meet certain specifications. The assembly quality is dependent on the distribution of variations of assembly dimensions, which is in turn dependent on mating conditions in the mechanical assembly. Since it is often difficult to measure the assembly dimensions in the production stages, they are not considered as a direct inspection objective. Rather, the inspection and evaluation of quality is carried out by specifying whether the assembly requirements satisfy the specified limits. Therefore, we can basethe process capability indices on the assembly dimensions. In most real life cases,... 

    Tolerance analysis of assemblies with asymmetric tolerances by unified uncertainty-accumulation model based on fuzzy logic

    , Article International Journal of Advanced Manufacturing Technology ; Volume 53, Issue 5-8 , 2011 , Pages 777-788 ; 02683768 (ISSN) Khodaygan, S ; Movahhedy, M. R ; Sharif University of Technology
    2011
    Abstract
    In mechanical assemblies, individual components are placed together to deliver a certain function. The performance, quality, and cost of the mechanical assembly are significantly affected by its tolerances. Toleranced dimensions inherently generate an uncertain environment in a mechanical assembly. This paper presents a proper method for tolerance analysis of mechanical assemblies with asymmetric tolerances based on an uncertainty model. This mathematical approach is based on fuzzy logic and tolerance accumulation models such as worst-case and root-sum-square methods. A fuzzy-based tolerance representation is developed to model uncertainty of tolerance components in the mechanical...