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    Flower-like boehmite nanostructure formation in two-steps

    , Article Journal of Coordination Chemistry ; Volume 67, Issue 3 , 1 February , 2014 , Pages 555-562 ; ISSN: 00958972 Zanganeh, N ; Zanganeh, S ; Rajabi, A ; Allahkarami, M ; Rahbari Ghahnavyeh, R ; Moghaddas, A ; Aieneravaie, M ; Asadizanjani, N ; Sadrnezhaad, S. K ; Sharif University of Technology
    Reaction between AlCl3 and TEA (triethanolamine) gave Al(OH)3 colloidal nanocrystals that were precursors to nucleation and growth of boehmite under hydrothermal conditions. Transition electron microscopic (TEM) observations revealed that flower-like nanostructures were produced through a binary self-assembly system. In the first stage, nanostrips organize themselves to form a bundle, because of NH4 + and TEA. In the second stage, the bundles form flower-like nanostructures due to the interaction of nitrate with TEA. The size of the nanopetals (length 100-200 nm; width 100-150 nm; and thickness 20-70 nm) was measured through TEM. X-ray diffraction and Brunauer-Emmett-Teller (BET-N2) results... 

    Fabrication and applications of self-assembled nanopillars

    , Article AIMS Materials Science ; Volume 4, Issue 4 , 2017 , Pages 905-919 ; 23720484 (ISSN) Ji, H. F ; Samadi, M ; Gu, H ; Tomchak, V ; Qiao, Z ; Sharif University of Technology
    AIMS Press  2017
    In this mini-review, we summarize fabrication methods, formation mechanisms, factors that control the characteristics, and applications of self-assembled nanopillars. Nanopillars prepared both in the gas phase and in solutions are discussed. © 2017 Hai-Feng Ji, et al  

    Capacity Optimization of the Pride Engine Assembly Line

    , M.Sc. Thesis Sharif University of Technology Moalleman, Mehran (Author) ; Esharagh Niaye Jahromi, Abdolmajid (Supervisor)
    In this project optimization of the assembly line balancing of Pride Motor is considered. The technical specification and limitizations as well as the production process of the product of this line is studied and documented through opc-fpc diagram, and assembly charts. Differential time study procedures are studied and the stop watch approach is selected to calculate the normal time of each operation. Through evaluation of line bottle necks the most important stations are reconsidered and have been pointed out.Considering operations procedure, priorities of the operations in the line, number of operations in each station, and requirements of investments for the changes, a solution for... 

    A lean manufacturing roadmap for an automotive body assembly line within axiomatic design framework

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 17, Issue 1 , 2004 , Pages 51-72 ; 17281431 (ISSN) Houshmand, M ; Jamshidnezhad, B ; Sharif University of Technology
    National Research Center of Medical Sciences  2004
    In this paper we are to present a practical application of Axiomatic Design (AD) methodology, as a roadmap to lean production, in redesigning a car body assembly line. Axiomatic Design theory provides a framework to simplify the whole problem. According to the AD principles, a hierarchical structure has been developed. The developed structure originated in lean manufacturing principles and existing conditions of an assembly line, revealed that elimination of all kinds of waste is a prerequisite for other functional requirements. Several main sources of waste were recognized in the assembly line and some practical solutions are suggested to alleviate these problems. In the initial survey, it... 

    A new approach to assembly level programming

    , Article EUROCON 2007 - The International Conference on Computer as a Tool, Warsaw, 9 September 2007 through 12 September 2007 ; December , 2007 , Pages 439-445 ; 142440813X (ISBN); 9781424408139 (ISBN) Sahraeian, M. E ; Vosoughi Vahdat, B ; Sharif University of Technology
    In assembly level programming we need to know the mnemonic of each assembly instruction. But it is not so easy to remember mnemonics of all instructions, while the instruction set of Pentium processor includes 280 instructions. In this paper we introduce a new programming approach to assembly level programming in which most important assembly instructions (about 100 instructions) can be substituted for simple equivalents. These equivalent instructions are based on simple familiar operators and make a large simplification in assembly programming. This new language has a free format structure and hence is called Free Format Assembly Language. Evaluating the performance of this language using a... 

    Nanoparticulate hollow TiO 2 fibers as light scatterers in dye-sensitized solar cells: Layer-by-layer self-assembly parameters and mechanism

    , Article ChemPhysChem ; Volume 12, Issue 5 , 2011 , Pages 966-973 ; 14394235 (ISSN) Rahman, M ; Tajabadi, F ; Shooshtari, L ; Taghavinia, N ; Sharif University of Technology
    Hollow structures show both light scattering and light trapping, which makes them promising for dye-sensitized solar cell (DSSC) applications. In this work, nanoparticulate hollow TiO 2 fibers are prepared by layer-by-layer (LbL) self-assembly deposition of TiO 2 nanoparticles on natural cellulose fibers as template, followed by thermal removal of the template. The effect of LbL parameters such as the type and molecular weight of polyelectrolyte, number of dip cycles, and the TiO 2 dispersion (amorphous or crystalline sol) are investigated. LbL deposition with weak polyelectrolytes (polyethylenimine, PEI) gives greater nanoparticle deposition yield compared to strong polyelectrolytes... 

    Graphene-mediated self-assembly of gold nanorods into long fibers with controllable optical properties

    , Article Materials Letters ; Volume 224 , 2018 , Pages 13-17 ; 0167577X (ISSN) Bagheri, P ; Farivar, M ; Simchi, A ; Sharif University of Technology
    Elsevier B.V  2018
    The paper presents graphene-templated self-assembly of gold nanorods into long fibers with controllable optical properties. It is shown that the size of self-assembled nanostructures varies with time and is controlled by chemical reactions between amine groups of graphene and the functional groups of gold. The absorption peak of the nanostructures changes over time while the photoluminescence intensity is quenched. The self-assembled nanostructures with variable plasmon resonance effects are potentially usable for the fabrication of nanoscale devices for biomedical applications. © 2018 Elsevier B.V  

    Feasibility analysis of the use of rigid polyurethane foam in modular sandwich panels for rapid assembly structures

    , Article International Journal of GEOMATE ; Volume 15, Issue 51 , 2018 , Pages 113-120 ; 21862982 (ISSN) Samali, B ; Nemati, S ; Sharafi, P ; Yaghmaei, F ; Farrokhi, A ; Sharif University of Technology
    GEOMATE International Society  2018
    Mobile and rapidly assembled structures play an important role in building temporary and semi-permanent accommodations and shelters in post-disaster management. One of the most efficient construction systems that can be used in rapidly assembled buildings is lightweight panelized systems. Use of rapidly assembled panelized systems is becoming very popular for cutting the construction time and transportation costs that make them suitable options for rapid assembly construction. In addition, when acoustic and thermal insulation of buildings is important, foam filled composite sandwich panels are an effective solution. Soft, semi-rigid and rigid Polyurethane (PU) foams, which are first... 

    An imperialist competitive algorithm in mixed-model assembly line sequencing problem to minimise unfinished works

    , Article International Journal of Systems Science: Operations and Logistics ; Volume 6, Issue 2 , 2019 , Pages 179-192 ; 23302674 (ISSN) Zandieh, M ; Moradi, H ; Sharif University of Technology
    Taylor and Francis  2019
    Mixed-model assembly lines (MMALs) are a type of production lines where a variety of product models similar to product characteristics are assembled in a just-in-time production system. Usually, MMAL consists of a number of stations linked by a conveyor belt and each station has a work zone limited by upstream and downstream boundaries. To avoid improper interference between operators in the adjacent stations and excess of machine moving range, operators are forced to complete their operations within their predetermined work zone. There is a set of criteria on which to judge sequences of product models in terms of the effective utilisation of these lines. In this paper, the sequence of... 

    Glycan-mediated functional assembly of IL-1RI: structural insights into completion of the current description for immune response

    , Article Journal of Biomolecular Structure and Dynamics ; 2020 Azimzadeh Irani, M ; Ejtehadi, M. R ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Interleukin 1 Receptor type I (IL-1RI) is a multi-domain transmembrane receptor that triggers the inflammatory response. Understanding its detailed mechanism of action is crucial for treating immune disorders. IL-1RI is activated upon formation of its functional assembly that occurs by binding of the IL-1 cytokine and the accessory protein (Il-1RAcP) to it. X-ray crystallography, small-Angle X-ray Scattering and molecular dynamics simulation studies showed that IL-1RI adopts two types of ‘compact’ and ‘extended’ conformational states in its dynamical pattern. Furthermore, glycosylation has shown to play a critical role in its activation process. Here, classical and accelerated atomistic... 

    A multi-objective lead time control problem in multistage assembly systems using an interactive method

    , Article Applied Mathematics and Computation ; Volume 176, Issue 2 , 2006 , Pages 609-620 ; 00963003 (ISSN) Azaron, A ; Kianfar, F ; Sharif University of Technology
    In this paper, we develop a multi-objective model to optimally control the lead time of a multistage assembly system, using an interactive method. The multistage assembly system is modelled as an open queueing network, whose service stations represent manufacturing or assembly operations. It is assumed that the product order arrives according to a Poisson process. In each service station, there is either one or infinite number of servers (machines) with exponentially distributed processing time, in which the service rate (capacity) is controllable. The transport times between the service stations are independent random variables with generalized Erlang distributions. The problem is... 

    A simulation optimization approach to un-paced assembly line balancing problem-II with additional reworking issue

    , Article 2011 4th International Conference on Modeling, Simulation and Applied Optimization, ICMSAO 2011, 19 April 2011 through 21 April 2011 ; April , 2011 , Page(s): 1 - 6 ; 9781457700057 (ISBN) Noushabadi, M. E ; Bahalke, U ; Dolatkhahi, K ; Yolmeh, A. M ; Sharif University of Technology
    This paper investigates the problem of assembly line balancing problem, in which the products in the production line may undergo to be reworked on the current task. Since the real manufacturing systems deal with the stochastic nature of the items in production lines, this paper considers the simple assembly line balancing problem type 2 (SALBP-II) under the conditions of stochastic processing time of tasks and the element of reworking system. Exposing to the stochastic conditions encouraged us to handle the problem via simulation optimization procedure, which uses the well known genetic algorithm as an optimization tool. Results show the adaptation and effectiveness of GA to considered... 

    Statistical error analysis for dimensional control in automotive body assembly process

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010 ; Volume 3 , 2010 , Pages 329-334 ; 9780791849170 (ISBN) Khodaygan, S ; Movahhedy, M. R ; Mirabolghasemi, A ; Zendehbad, M ; Moradi, H ; Sharif University of Technology
    In mechanical assemblies, the performance, quality, cost and assemblability of the product are significantly affected by the geometric errors of the parts. This paper develops the statistical error analysis approach for dimensional control in automotive body multi-station assembly process. In this method, the homogeneous transformation matrices are used to describe the location and orientation of part and assembly features and the small homogeneous transformation matrices are used to model the errors. In this approach, the effective errors in automotive body assembly process are classified in three categories: manufacturing errors (dimensional and geometric tolerances), locating errors... 

    Probabilistic tolerance analysis of compliant assemblies

    , Article 2007 World Congress, Detroit, MI, 16 April 2007 through 19 April 2007 ; 2007 ; 01487191 (ISSN) Babaei, E ; Movahhedy, M. R ; Sharif University of Technology
    SAE International  2007
    Tolerance analysis is essential for estimation of final error of key product characteristic (KPC) in a mechanical assembly caused by errors in production and assembly of individual parts. Many mechanical assemblies, especially in automotive and aerospace industries, include sheet metal parts with a small ratio of thickness to width or length. Such parts are substantially flexible and thus, are prone to large errors due to elastic deformations during assembly production. Phenomena such as deformation due to fixture force, spring back, welding distortion and so on are common to such parts. Unlike tolerance analysis of rigid parts, here, the elastic deformation of the parts plays a significant... 

    The type e simple assembly line balancing problem: A mixed integer linear programming formulation

    , Article Computers and Operations Research ; Volume 64 , 2015 , Pages 168-177 ; 03050548 (ISSN) Esmaeilbeigi, R ; Naderi, B ; Charkhgard, P ; Sharif University of Technology
    Elsevier Ltd  2015
    Although the simple assembly line balancing problem (SALBP) is the topic of many studies, typically they either consider minimizing the number of stations for a given cycle time (called type one), or minimizing the cycle time for a given number of stations (called type two). Rarely, type E of the problem has been considered. In the type E, cycle time and number of stations are both decision variables, and the objective is to maximize the line efficiency. This paper presents a mixed integer linear programming formulation for the type E simple assembly line balancing problem. Moreover, to further strengthen the presented formulation, two enhancement techniques in the form of valid inequalities... 

    Supramolecular self-assembly of oleylamide into organogels and hydrogels: a simple approach in phase selective gelation of oil spills

    , Article Soft Materials ; Volume 18, Issue 1 , 2020 , Pages 55-66 Eftekhari Sis, B ; Bagheri, A ; Younesi Araghi, H ; Akbari, A ; F. Paige, M ; Sharif University of Technology
    Taylor and Francis Inc  2020
    A new gelator based of oleylamide has been introduced, which was gelled nonpolar hydrocarbon and CCl4 solvents through self-assembly. Also, the gelator formed a two-component hydrogel in combination with SDS, an anionic surfactant. UV-Vis studies revealed that the H-type and J-type aggregation of organogels in hexane and hydrogel in water, respectively. The xerogel, obtained by evaporating the solvent of organogel, selectively gelled and adsorbed oil spills on water surfaces. The effect of the various parameters, including temperature, water acidity and pH on the oil spill adsorption was studied, revealing the high ability of the xerogel to removing the oil contamination from water in up to... 

    Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum dots

    , Article ACS Applied Nano Materials ; 2021 ; 25740970 (ISSN) Fahimi Kashani, N ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M.R ; Sharif University of Technology
    American Chemical Society  2021
    Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

    U-Shaped Assembly Line Rebalancing With Cost Minimization Objectives

    , M.Sc. Thesis Sharif University of Technology Khoshnood, Sara (Author) ; Akbari, Javad (Supervisor)
    U-shaped assembly lines usually are more effective than straight lines. Therefore special attention has been paid to u-shaped line balancing problem in recent years. On the other hand most articles on the line balancing problems are investigated for the first time. However, within the lifetime of an ALB, the balancing problems do not occur only once prior to its construction, but rather continuously as rebalancing. For example whenever the demand structure or production technology changes or producing seasonal products, the ALB needs to be reconfigured. So many balancing issues in the real world are related to re-balancing of production lines.
    Therefore in this study, U-shaped assembly... 

    Assembly Line Evaluation and Optimization Focusing on Operators with Disability Using Augmented Reality Technology

    , M.Sc. Thesis Sharif University of Technology Nikoonejad, Morteza (Author) ; Haji, Alireza (Supervisor) ; Fatahi Valilaei, Omid (Co-Supervisor)
    Virtual reality (VR) is a technology which allows a user to interact with a computer-simulated environment, whether that environment is a simulation of the real world or an imaginary world. Virtual reality promotes interaction and perception of the user with the real world. Virtual elements of this technology present information for the user that the user could not identify them before.The term virtual reality is commonly used by the popular media to describe imaginary worlds that only exist in computers and our minds. AR is based on techniques developed in VR and interacts not only with a virtual world but has a degree of interdependence with the real world. Research on the manufacturing... 

    Neutronic analysis of HPLWR fuel assembly cluster

    , Article Annals of Nuclear Energy ; Volume 50 , December , 2012 , Pages 38-43 ; 03064549 (ISSN) Tashakor, S ; Salehi, A. A ; Jahanfarnia, G ; Abbaspour Tehrani Fard, A ; Sharif University of Technology
    In the present study the neutronic analysis of fuel assembly cluster of the HPLWR is discussed. Neutronic calculations are performed using WIMS-D4 and CITATION codes. Thermal-hydraulic code containing the properties and specifications of the fuel assembly of HPLWR is utilized. The calculated axial power in each selected control volume is used in the thermal-hydraulic code to get the properties of the fluid and fuel needed for further neutronic analysis. The process of coupling continues until convergence is achieved. Finally, the obtained neutronic results including axial power distribution, neutron flux, and power peaking factors are discussed in the present article