Search for: lubrication
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    Effects of lubrication procedure on the consolidation, sintering and microstructural features of powder compacts

    , Article Materials and Design ; Volume 24, Issue 8 , 2003 , Pages 585-594 ; 02641275 (ISSN) Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2003
    The role of lubrication procedure on the consolidation behavior of metallic powders and subsequent microstructural development during sintering was investigated. Iron powder and iron-0.8 w/o graphite powder mixture were used as model materials. The effects of die wall lubrication procedure were compared to the traditional admixed powder lubrication method. The influences of manufacturing parameters such as the compacting pressure in the range of 150-800 MPa and the sintering temperature from 400 to 1300 °C were studied. It was found that the lubrication procedure has a great influence on the consolidation and microstructural features of the materials investigated. Admixed lubricant aids the... 

    Microbial population control in emulsion oil

    , Article Scientia Iranica ; Volume 6, Issue 5 , 2000 , Pages 111-114 ; 10263098 (ISSN) Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
    Sharif University of Technology  2000
    In this paper, controlling microbial degradation of water based metalworking system fluid, emulsion oil, is investigated using glutaraldehyde as biocide. Microbial population was determined through colony counting method. Evaluation and results demonstrate that a 15 day treatment by glutaraldehyde results in higher resistance to microbial deterioration. Analysis of variance through multiple comparison tests was conducted and Least Significant Difference (LSD) was determined. An overall observed paired difference between the first and second treatment is significant; therefore, the first treatment, with an addition of glutaraldehyde every 15 days is suggested  

    Effect of different lubricant on microstructure of second cold rolled silicon steel used in transformer core

    , Article Proceedings of the 10th International Conference on Steel Rolling, 15 September 2010 through 17 September 2010, Beijing ; 2010 ; 9787502453596 (ISBN) Eftekhari, S. A ; Akbarzade, A ; Mirahmadi Khaki, D ; Aminnejad, F ; Sharif University of Technology
    One of the important parts of each transformer is core. It is made from multilayer silicon steel sheets. Silicon steel has high magnetic permission, high electrical resistance and minimum hysterics loss. In different metal forming process, lubrication is done for reducing friction effects. In this research, effect of 3 different type lubricants, mineral material (castor oil), organic material (glycerol), and semi organic material (paraffin) with and without additive (graphite) is investigated. Also, effect of 2 industrial lubricants (suds and motor oil) is compromised with above lubricants. Results show the best lubricant for second cold rolling of silicon steel is semi organic (paraffin)... 

    Nanomaterial-assisted pyrolysis of used lubricating oil and fuel recovery

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Alavi, E ; Abdoli, M. A ; Khorasheh, F ; Nezhadbahadori, F ; Bayandori Moghaddam, A ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas... 

    Analaysis of Ultrasonic Vibration Assisted Turing of Engineering Ceramics

    , M.Sc. Thesis Sharif University of Technology Zabihi Hosseini, Morteza (Author) ; Movahhedi, Mohammad Reza (Supervisor) ; Akbari, Javad (Supervisor)
    Due to high strength, hardness and high resistance to abrasion, ceramics are difficult for machining. Also as the conductivity coefficient of these materials is low, major amount of produced heat during machining process will be absorbed in the cutting tool which causes intensive wear in cutting tool edge. As a result employing traditional machining for these materials because of low machining speed, tool wear, high roughness and large cutting force, has little efficiency in practice. Therefore non-traditional machining method may improve efficacy. In this thesis effect of utilizing ultrasonic vibration in machining process of fused cast silica ceramic has been studied. Aim of this study at... 

    Experimental Study of the Ionic Liquids Application in the Minimum Quantity Lubrication System for Drilling P20 Steel

    , M.Sc. Thesis Sharif University of Technology Mostafaloo, Mohsen (Author) ; Akbari, Javad (Supervisor)
    This study investigates the application of ionic liquids as a lubricant in the minimal lubrication system for P20 steel drilling. due to the wide use of cutting fluids in machining processes, it is important to research in this regard to reduce emissions of pollutants, reduce friction, and consequently reduce energy consumption and machining costs. in recent years, ionic liquids have been considered as a new lubricant due to the structure and composition of the special chemical in the fields of: bearings, metal forming, etc. however, in the application of ionic liquids as fluids In the process of machining, very little research has been done. Therefore, deserves that examining the effect of... 

    Design and Analysis of Engine Lubrication System for SP1 Engine

    , M.Sc. Thesis Sharif University of Technology Mohamadlou, Mohamad (Author) ; Shafie, Mohamad Behshad (Supervisor)
    Oil pump is a prominent part which has been described as a vehicle heart. Any malfunction or improper design may lead to engine failure. beside engine, proper design of oil route and lubrication system of vehicle, are main factor in engine design, which provide higher efficiency with lower pressure drop. lubrication system should be able to provide required pressure and flow of oil in vast range of engine rotation speed. also minimum energy waste in higher rpm is a key factor which happens due to reverse flow from output to input of pump in the relief valve. The aim of this thesis focus on design of oil pump and lubrication system of 4 cylinder 16 valve of 1600 cc inline engine. which is... 

    Lubricating flow of thixotropic fluids in slipper-pad bearing: A numerical study

    , Article Nihon Reoroji Gakkaishi ; Volume 39, Issue 4 , 2011 , Pages 153-158 ; 03871533 (ISSN) Najmi, K ; Karimzadeh, M ; Sadeghy, K ; Sharif University of Technology
    Laminar, two-dimensional flow of an incompressible thixotropic fluid obeying Moore's model is investigated numerically in a slipper-pad bearing using FVM method. Results will be presented addressing the effect of thixotropic properties and inclination angle on the pressure distribution and load-carrying capacity of the bearing. It is shown that the pressure distribution under the upper pad depends only on the buildup-to-breakdown ratio. It is also predicted that by increasing this ratio, the load-carrying capacity increases, but, the pressure distribution becomes more and more asymmetric with the maximum pressure shifting towards the outlet section of the bearing. Also, for any given set of... 

    An Experimental Investigation on the Effects of MQL Method on Grinding of Nickel Based Superalloy 738 (Inconel 738)

    , M.Sc. Thesis Sharif University of Technology Khazali, Mohsen (Author) ; Akbari, Javad (Supervisor)
    The issues relevant to lubricants in industry, construction and production processes such as machining and grinding have been recently taken into serious consideration. Unlike the positive effects of applying lubricants on machining forces, chip formation, thermal defects which lead to force reduction, lower power consumption and surface quality improvement, its conventional usage has adverse effects such as environmental problems, high cost of high volume lubricant application as well as recycling problems. Therefore, attention was drawn toward chip removal under dry or near dry conditions and as thermal defects such as surface burning is important particularly in grinding, grinding under... 

    Friction and wear performance of copper-graphite surface composites fabricated by friction stir processing (FSP)

    , Article Wear ; Volume 304, Issue 1-2 , 2013 , Pages 1-12 ; 00431648 (ISSN) Sarmadi, H ; Kokabi, A. H ; Seyed Reihani, S. M ; Sharif University of Technology
    Copper-graphite composites which have low friction coefficient can be used as bearing materials in lieu of materials containing lead which cause environmental problems. So far, some methods such as powder metallurgy and centrifugal casting have been employed to produce these composites. In this study, friction stir processing (FSP) was used to produce copper-graphite surface composites. Five tools with different pin profile were employed in order to achieve a comprehensive dispersion. Results show that the tool with triangular pin gives rise to a better dispersion of graphite particles. Furthermore, four copper-graphite composites containing different graphite content were prepared using... 

    Microstructure and Mechanical Properties of Hybrid Aluminum Matrix Composite Reinforced by Graphite Particles and Zirconium Oxide Nanoparticles Fabricated by Friction Stir Processing

    , M.Sc. Thesis Sharif University of Technology Keshavarz, Hossein (Author) ; Kokabi, Amir Hossein (Supervisor)
    In this research, aluminum matrix composites (AMCs) reinforced by different contents of zirconium dioxide nanoparticles, graphite microparticles, and a mixture of both with various hybrid ratios, into a cold-rolled Aluminum1050 as base metal, fabricated by 4-passes friction stir processing. Observations show that the processing of composites reinforced by Gr particles is significantly hard due to the low friction coefficient of graphite resulting in the decline in the maximum temperature during the process and the type of base metal. The mixtures of graphite and zirconia resulted in more homogenous dispersion of particles in the matrix due to deterring a drastic drop in friction coefficient... 

    Non-isothermal pyrolysis of used lubricating oil and the catalytic effect of carbon-based nanomaterials on the process performance

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 139, Issue 2 , 2020 , Pages 1025-1036 Alavi, E ; Abdoli, M. A ; Khorasheh, F ; Bayandori Moghaddam, A ; Sharif University of Technology
    Springer Netherlands  2020
    Pyrolysis is a commonly used method for the recovery of used lubricating oil (ULO), which should be kinetically improved by a catalyst, due to its high level of energy consumption. In this research, the catalytic effects of carbon nanotube (CNT) and graphene nanoplatelets on the pyrolysis of ULO were studied through thermogravimetric analysis. First, the kinetic parameters of ULO pyrolysis including activation energy were calculated to be 170.12 and 167.01 kJ mol−1 by FWO and KAS methods, respectively. Then, the catalytic effects of CNT and graphene nanoplatelets on pyrolysis kinetics were studied. While CNT had a negligible effect on the pyrolysis process, graphene nanoplatelets... 

    , M.Sc. Thesis Sharif University of Technology Hassan Beigee, Hamid Reza (Author) ; Ghorbani, Mohammad (Supervisor)
    Phosphating is one of the most procedures as a final surface treatment or pre-treatment (lubrication and Infrastructure color) is done on ferrous and nonferrous alloys. Phosphate coating on the wire drawing, increase speed of drwing, increase die life, increased resistance to abrasion caused by the friction reduction, reduced maintenance costs and improved surface appearance are combustible and conditions. The aim of this study was to evaluate the effects of variables such as temperature, pH bath, the coating bath components concentration on coating properties and optimize calcium zinc phosphate coating on steel wire, for better lubrication and decrease friction in the wire drawing process.... 

    Investigation on the Effect of Improper Lubrication on the Performance of Rolling Element Bearings

    , M.Sc. Thesis Sharif University of Technology Mosayebi Kulluje, Reza (Author) ; Behzad, Mehdi (Supervisor) ; Hoviattalab, Maryam (Supervisor)
    In this project, the effect of improper lubrication on vibrational behavior of rolling element bearings is investigated. Different lubrication conditions were deliberately produced using three oils with different viscosity grades on a bearing at different loads and speeds. The acceleration of bearing vibrations were measured, then analyzed by means of squared envelope analysis, a special case of cyclostationary analysis. The results and their comparison showed that decrease in lubricant’s viscosity grade can lead to an increase in magnitude of cyclic frequencies equal to cage frequency and its harmonics. This observation can be helpful in detection of lubricant degradation and in... 

    Mechanical Properties of Lubricants in Nano Powders Compaction Process Using Molecular Dynamics and Continuum Mechanics Methods

    , M.Sc. Thesis Sharif University of Technology Palahang, Pezhman (Author) ; Khoei, Amir Reza (Supervisor)
    The primary objective of this study entails the examination of the impact of lubricants intended for implementation in the compaction process of nano-powders, intending to mitigate friction at the nano scale during compaction. Molecular dynamics modeling is employed to scrutinize this phenomenon and derive the friction parameters within the framework of equations derived from continuum mechanics, based on data acquired from the nanoscale investigations. The manufacturing procedure of metallic components from metal powder compaction necessitates the application of immense pressures, thereby engendering notable friction between the powder particles and the confines of the mold. Consequently,... 

    Dewetting of evaporating thin films over nanometer-scale topographies

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Vol. 90, issue. 1 , July , 2014 ; ISSN: 15393755 Akbarzadeh, A. M ; Moosavi, A ; Moghimi Kheirabadi, A ; Sharif University of Technology
    A lubrication model is used to study dewetting of an evaporating thin film layer over a solid substrate with a nanometer-scale topography. The effects of the geometry of the topography, the contact angle, the film thickness, and the slippage on the dewetting have been studied. Our results reveal that the evaporation enhances the dewetting process and reduces the depinning time over the topography. Also it is shown that the depinning time is inversely proportional to the slippage and increasing the contact angle may considerably reduce the depinning time, while the film thickness increases the depinning time  

    Coupled effects of suction and degree of saturation on large strain shear modulus of unsaturated sands

    , Article Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 ; Vol. 2, issue , July , 2014 , p. 1559-1564 ; 978-1-138-00150-3 Jafarzadeh, F ; Ahmadinezhad, A ; Sadeghi, H ; Sharif University of Technology
    Predictions of soil behavior in response to dynamic loads require an understanding of dynamic properties of soil. Studies on dynamic properties of unsaturated soils at large-strains are quite limited, while some dynamic loadings, like earthquakes, are in the medium to large-strain ranges. A cyclic simple shear apparatus was developed to measure large-strain shear modulus and damping ratio under different matric suction or degree of saturation. Six cyclic tests, with referring to the soil-water retention curve, were conducted on clean medium sand. Results indicated that shear modulus slightly increases when suction varies from zero up to the air entry value. Approaching the residual value, a... 

    Droplet breakup in an asymmetric microfluidic T junction

    , Article European Physical Journal E ; Volume 34, Issue 8 , 2011 ; 12928941 (ISSN) Bedram, A ; Moosavi, A ; Sharif University of Technology
    Breakup of non-uniform droplets in an asymmetric T junction consisting of an inlet channel and two different-size outlet channels has been investigated numerically. Also, an analytical approach in the limit of the lubrication approximation has been extended to provide some analytical relations to study the system and verify the numerical results. Parameters that are important in the performance of the system have been determined and discussed. Our results indicate that smaller droplets can be produced by increasing the capillary number. As the geometry becomes symmetric the pressure drop decreases. Our results also reveal that the breakup time and the pressure drop for this system are... 

    Dynamics of nanodroplets on wettability gradient surfaces

    , Article Journal of Physics Condensed Matter ; Volume 23, Issue 8 , February , 2011 ; 09538984 (ISSN) Moosavi, A ; Mohammadi, A ; Sharif University of Technology
    A lubrication model is used to study the dynamics of nanoscale droplets on wettability gradient surfaces. The effects of the gradient size, size of the nanodroplets and the slip on the dynamics have been studied. Our results indicate that the position of the center of mass of the droplets can be well described in terms of a third-order polynomial function of the time of the motion for all the cases considered. By increasing the size of the droplets the dynamics increases. It is also shown that the slip can considerably enhance the dynamics. The results have been compared with the results obtained using theoretical models and molecular dynamics simulations  

    Production of Cu-Sn-graphite-SiC composite coatings by electrodeposition

    , Article Surface and Coatings Technology ; Volume 216 , 2013 , Pages 207-214 ; 02578972 (ISSN) Asnavandi, M ; Ghorbani, M ; Kahram, M ; Sharif University of Technology
    Cu-Sn composites incorporated with graphite and/or SiC particles were produced by electrodeposition technique. The effect of particle concentration in the plating bath and current density on tin content and volume percentage of particles in the coatings has been investigated. Structure, morphology, micro hardness and wear properties of the coatings have been studied. The results showed that particles cause an increase of tin content in the plated Cu-Sn. Graphite and silicon carbide particles had different effects on coating hardness; 7.8. vol.% graphite decreased the hardness of Cu-Sn layer from 231. Hv to 172. Hv whereas, 5.1. vol.% SiC raised the hardness to 316. Hv. Moreover, friction...