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Effect of geometry on the fixation strength of anterior cruciate ligament reconstruction using bashti technique
, Article Journal of Knee Surgery ; Volume 35, Issue 5 , 2022 , Pages 539-547 ; 15388506 (ISSN) ; Nourani, A ; Borjali, A ; Mohseni, M ; Ghias, N ; Korani, H ; Chizari, M ; Sharif University of Technology
Georg Thieme Verlag
2022
Abstract
The goal of this study is to investigate the effects of tendon and cannulated drill bit diameter on the strength of the bone and site hold tendon inside (BASHTI) fixation technique for an anterior cruciate ligament (ACL) reconstruction. Bovine digital tendons and Sawbones blocks were used to mimic the ACL reconstruction. Mechanical strength of the specimens was measured using a cyclic loading continued by a single cycle pullout load until failure to simulate the real postsurgical loading conditions. Finally, failure modes of specimens and ultimate failure load were recorded. The maximum possible tendon surface strain (i.e., tendon compression [TC]) for tendon diameters of 6, 7, 8, and 9 mm...
A comprehensive approach for the validation of lumbar spine finite element models investigating post-fusion adjacent segment effects
, Article Journal of Biomechanics ; Volume 121 , 2021 ; 00219290 (ISSN) ; Arjmand, N ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Spinal fusion surgery is usually followed by accelerated degenerative changes in the unfused segments above and below the treated segment(s), i.e., adjacent segment disease (ASD). While a number of risk factors for ASD have been suggested, its exact pathogenesis remains to be identified. Finite element (FE) models are indispensable tools to investigate mechanical effects of fusion surgeries on post-fusion changes in the adjacent segment kinematics and kinetics. Existing modeling studies validate only their intact FE model against in vitro data and subsequently simulate post-fusion in vivo conditions. The present study provides a novel approach for the comprehensive validation of a lumbar...
The effect of mixing molar ratios and sand particles on microstructure and mechanical properties of metakaolin-based geopolymers
, Article Materials Chemistry and Physics ; Volume 240 , 2020 ; Nemati, A ; Khodabandeh, A. R ; Baghshahi, S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this study the influence of the molar ratios such as SiO2:Al2O3:Na2O:H2O, as well as the sand particles on the mechanical performance, shrinkage and microstructure of metakaolin based geopolymers was studied. Considering different content of the reactive silica and alumina in metakaolin, forty eight different compositions were prepared. The proper condition for achieving the highest mechanical performance as well as less structural defects by tailoring the curing condition, molar ratios and addition of sand particles are presented. Special attention was paid to the incorporation of sand particles up to 70 wt% on the microstructure, shrinkage and mechanical properties of metakaolin based...
Effect of mineral fillers on the performance, rheological and dynamic viscosity measurements of asphalt mastic
, Article Construction and Building Materials ; Volume 222 , 2019 , Pages 390-399 ; 09500618 (ISSN) ; ur Rehman, Z ; Hassan Khan, A ; Qamar, S ; Niaz Akhtar, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The principal objective involved in this research is to explore the mechanical behaviour of the binder using different mineral fillers such as stone dust (SD), brick dust (BD) and fly ash Class F (FA). Currently, a large quantity of roads is being constructed under the China-Pakistan Economic Corridor (CPEC) project. It is a major concern for quality of road to with stand heavy loads. For the investigation of the quality of roads, it is mandatory to evaluate the behaviour of mineral fillers addition in asphalt mastic. Fatigue cracking, thermal cracking and permanent deformation have been found a major common distress in the construction of road networks. In this study, the behaviour of...
Experimental and numerical study on choosing proper pulse shapers for testing concrete specimens by split hopkinson pressure bar apparatus
, Article Construction and Building Materials ; Volume 125 , 2016 , Pages 326-336 ; 09500618 (ISSN) ; Naghdabadi, R ; Ashrafi, M. J ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Dynamic behavior of concrete specimens is investigated experimentally and numerically by split Hopkinson pressure bar (SHPB) tests. In order to accurately determine dynamic properties of brittle materials such as concrete, specimens should be subjected to particular pulse loading that can be generated by using pulse shapers. Choosing proper pulse shaper dimensions helps to obtain dynamic stress equilibrium, achieve constant strain rate and minimize pulse oscillation in the concrete specimens. To this end, SHPB tests are performed for concrete specimens and effective parameters on shaping pulses such as striker bar velocity, diameter and thickness of the pulse shaper are studied...
Test data compression strategy while using hybrid-BIST methodology
, Article Proceedings of IEEE East-West Design and Test Symposium, EWDTS 2013, Rostov-on-Don ; Sept , 2013 ; 9781479920969 (ISBN) ; Tabandeh, M ; Haghbayan, M. H ; Sharif University of Technology
2013
Abstract
In this paper a strategy is proposed for compressing the test data while using concurrent hybrid-BIST methodologyfor testing SoCs. In the proposed method, in addition tousing BIST strategy for testing cores with deterministic sequential test patterns in an SoC( Without using scan chains), (ATE) is used for testing cores with deterministic test patterns through Test Access Mechanism (TAM) or functional bus. As will be shown in experimental results, this process compresses hybrid-BIST overall test patterns considerably that affects the overall Test Application Time (TAT) in comparison with pure deterministic, pure pseudo random, and combination of deterministic and pseudo random test patterns
Effect of molybdenum on grain boundary segregation in Incoloy 901 superalloy
, Article Materials and Design ; Volume 46 , 2013 , Pages 573-578 ; 02641275 (ISSN) ; Abbasi, S. M ; Sharif University of Technology
2013
Abstract
In this paper, the effect of molybdenum on the grain boundary segregation of other elements was studied in Incoloy 901 superalloy. Initially, five alloys were prepared with different percentages of Mo by using a vacuum induction furnace. Then, these alloys were remelted by Electro-slag remelting (ESR) process and after homogenizing at 1160 °C for 2. h followed by air cooling, were rolled. The effect of Mo on segregation of elements was evaluated with Scanning Electron Microscopy, Linear Analysis, and the mechanical tests. The results showed that the grain boundary segregations of elements in Incoloy 901 superalloy were decreased by increasing of molybdenum content up to 6.7% and the...
Effect of 10Ce-TZP/Al2O3 nanocomposite particle amount and sintering temperature on the microstructure and mechanical properties of Al/(10Ce-TZP/Al2O3) nanocomposites
, Article Materials and Design ; Volume 50 , 2013 , Pages 85-91 ; 02641275 (ISSN) ; Pech Canul, M. I ; Bahrami, A ; Sharif University of Technology
Elsevier Ltd
2013
Abstract
A zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al2O3 nanocomposite) can be a good substitute as reinforcement in metal matrix composites. In the present study, the effect of the amount of 10Ce-TZP/Al2O3 particles on the microstructure and properties of Al/(10Ce-TZP/Al2O3) nanocomposites was investigated. For this purpose, aluminum powders with average size of 30μm were ball-milled with 10Ce-TZP/Al2O3 nanocomposite powders (synthesized by aqueous combustion) in varying amounts of 1, 3, 5, 7, and 10wt.%. Cylindrical-shape samples were prepared by pressing the powders at 600MPa for 60min while heating at 400-450°C. The specimens were then characterized by scanning and...
Ceria reinforced nanocomposite solder foils fabricated by accumulative roll bonding process
, Article Journal of Materials Science: Materials in Electronics ; Volume 23, Issue 9 , September , 2012 , Pages 1698-1704 ; 09574522 (ISSN) ; Kokabi, A. H ; Miyashita, Y ; Mutoh, Y ; Rezayat, M ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer
2012
Abstract
As one of the key technologies for high performance electronic devices, composite solders have been recently developed to improve thermal and mechanical properties of solder joints. In this study, accumulative roll bonding process was used as an effective alternative method for manufacturing high-strength, finely dispersed, void-free and highly uniform Sn-Ag-Cu/CeO 2 nanocomposite solders. Microstructural investigation of nanocomposite solders revealed that homogenous distribution of CeO 2 nanoparticle has been achieved and the eutectic as-cast morphology of the solder changed to recrystallized fine grained structure. As a result of severe plastic deformation during rolling, brittle and...
Electrodeposition and characterization of Ni-Co/SiC nanocomposite coatings
, Article Journal of Alloys and Compounds ; Volume 509, Issue 39 , 2011 , Pages 9406-9412 ; 09258388 (ISSN) ; Dolati, A ; Ahmadi, M. R ; Sharif University of Technology
2011
Abstract
Ni-Co/SiC nanocomposite coatings were electrodeposited in a modified watt type of Ni-Co bath containing 20 nm SiC particles to be codeposited. Potentiodynamic polarization tests were conducted to study the effect of the SiC particulates on the electrodeposition of Ni and Co. Scanning electron microscopy was used to assess the morphology of the Ni-Co alloy and Ni-Co/SiC nanocomposite coatings. The distribution of the particulates in the matrix was considered by means of transmission electron microscopy. Applying nanomechanical testing instruments coupled to atomic force microscopy, mechanical properties of the alloy and composite coatings were studied and compared. The presence of 11 vol.%...
On the formation of intermetallics during the furnace brazing of pure titanium to 304 stainless steel using Ag (30-50%)-Cu filler metals
, Article Materials and Manufacturing Processes ; Volume 25, Issue 11 , 2010 , Pages 1333-1340 ; 10426914 (ISSN) ; Abachi, P ; Dehghani, K ; Pourazarang, K ; Sharif University of Technology
2010
Abstract
In the present work, the effect of brazing pa rameters on the properties of the brazed joint of pure titanium and 304 stainless steel (304SS) was investigated. Three different Ag-Cu filler metals were used, while the temperature and time of brazing were in the range of 800-950°C and 5-45 minutes, respectively. The microstructural observations show that, depending on the brazing conditions, different intermetallic phases such as CuTi2, CuTi, Cu3Ti4, and FeTi were formed at the phases interface. Based on the microstructural observations, a model was developed to characterize the formation of phases at the interfaces and brazed joint. The results show that, while some phases may form during the...
Production of granulated-copper oxide nanoparticles for catalytic application
, Article Journal of Materials Research ; Volume 25, Issue 10 , 2010 , Pages 2025-2034 ; 08842914 (ISSN) ; Ahmadi, S. J ; Mousavand, T ; Outokesh, M ; Sharif University of Technology
2010
Abstract
Ultra fine CuO nanoparticles In the range of 2 ± 0.2 nm were synthesized by the supercritical hiydrotliermal method in a batch reactor. Itwas demonstrated that elevating the pH of the Cu2+ precursor solution to around 6 (neutral condition) not only does not lead to excessive agglomeration of the particles, but also reduces particle size and in general promotes their nanoscale characteristics. Prepared nanoparticles were immobilized in the biopolymcric matrix of barium alginate and calcined at different temperatures resulting in micro spherical granules of high porosity and elevated mechanical strength. The fabricated samples were characterized using x-ray diffractometry (XRD), transmission...
Effect of rolling speed on the occurrence of strain aging during and after warm rolling of a low-carbon steel
, Article Journal of Materials Science ; Volume 45, Issue 13 , July , 2010 , Pages 3405-3412 ; 00222461 (ISSN) ; Ohadi, D ; Serajzadeh, S ; Akhgar, J. M ; Sharif University of Technology
2010
Abstract
In this study, effect of rolling speed on strain aging phenomena in warm rolling of a carbon steel has been investigated. For this purpose, by using a mathematical model and predicting temperature and strain rate fields, the possibility of occurrence of dynamic strain aging during the warm rolling was first evaluated. In the next stage, warm-rolled samples were aged up to 11 months at room temperature for studying the kinetics of static strain aging, while mechanical tests as well as microstructural evolutions have been performed to determine the effect of strain aging on material behavior. The results indicate that dynamic strain aging may not occur for the employed rolling program;...
Microstructural study of a High Bainite Dual Phase (HBDP) steel austempered at different temperatures
, Article Defect and Diffusion Forum ; Volume 297-301 , 2010 , Pages 62-67 ; 10120386 (ISSN); 3908451809 (ISBN); 9783908451808 (ISBN) ; Ekrami, A ; Sharif University of Technology
Trans Tech Publications Ltd
2010
Abstract
4340 steel bars were austenitized at 850°C for 1 hour followed by heating at 700°C (ferrite and austenite region) for 90 min and quenching into a salt bath with different temperatures of 300, 350, 400 and 450°C. The steel bars were held for 1 hour at these temperatures before air cooling to room temperature. Various ferrite-bainite microstructures with 34% volume fraction of ferrite and different bainite morphologies were obtained. The results of SEM studies showed that by increasing the austempering temperature, the morphology of bainite varies from lower to upper bainite. According to the T-T-T diagram of the studied steel, the bainite transformation will not complete for the holding time...
Co-sintering of M2/17-4PH powders for fabrication of functional graded composite layers
, Article Journal of Composite Materials ; Volume 44, Issue 4 , 2010 , Pages 417-435 ; 00219983 (ISSN) ; Simchi, A ; Sharif University of Technology
2010
Abstract
Stepwise-graded composite layer of M2 tool stel and 17-4PH stainless steel was fabricated by a simple powder layering technique and the isothermal and nonisothermal sintering response of the bilayer were examined. It was shown that the materials exhibit poor compatibility during co-sintering, i.e., the amount of mismatch shrinkage is significant. An improved compatibility was obtained by adding 0.2 wt% B to the stainless steel powder. Formation of relatively dense layer at the bonding zone indicated an enhanced densification rate at the interface. Microstructural studies showed formation of a ferritic interface in M2/17-4PH composite and elongated grains with an intergranular boride phase...
Nanostructure and mechanical properties of 0-7 strained aluminum by CGP: XRD, TEM and tensile test
, Article Materials Science and Engineering A ; Volume 526, Issue 1-2 , 2009 , Pages 219-224 ; 09215093 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2009
Abstract
Commercial purity aluminum sheets are subjected to a severe plastic deformation technique called constrained groove pressing. In this study for the first time by using some technical optimizations, a strain magnitude of 6.9 is imposed to the sheets. The grain size evolution during severe plastic deformation is studied using Williamson-Hall analysis on X-ray diffraction pattern of the deformed samples. These results and transmission electron microscopy observations show that constrained groove pressing process can effectively refine the coarse-grained structure to an ultrafine grain range. The results of mechanical tests show that imposing strain in range of 0-5.75 causes to strengthening of...
An investigation into the effect of strain ageing on mechanical properties of low-carbon steels after warm rolling
, Article International Journal of Advanced Manufacturing Technology ; Volume 40, Issue 7-8 , 2009 , Pages 721-728 ; 02683768 (ISSN) ; Sharif University of Technology
2009
Abstract
In this study, the effect of strain ageing on mechanical properties of warm-rolled steel is investigated. Warm-rolling experiments together with mechanical testing are employed to investigate the effect of processing parameters on the ageing kinetics during and after warm rolling of a low-carbon steel. To do so, the occurrence of dynamic strain ageing is first determined by means of a two-dimensional thermo-mechanical model and then the effect of this phenomenon on the subsequent static strain ageing after warm rolling is studied employing mechanical testing. The results show that the occurrence of dynamic strain ageing during warm rolling may effectively alter the progress of the subsequent...
Comparison of mechanical properties of martensite/ferrite and bainite/ferrite dual phase 4340 steels
, Article Materials Science and Engineering A ; Volume 523, Issue 1-2 , 2009 , Pages 125-129 ; 09215093 (ISSN) ; Ekrami, A ; Sharif University of Technology
2009
Abstract
Different microstructures were produced by heat treatment of 4340 steel. These microstructures are bainite, martensite, ferrite-martensite and ferrite-bainite. Mechanical tests were carried out at room temperature. The results showed that steel with bainite-ferrite microstructure has better ductility and charpy impact energy than steels with martensite-ferrite and full bainite microstructures. But yield and tensile strengths of this steel are less than the yield and tensile strengths of the other two steels. Hardness measurements showed that their hardness is the same. Fracture surface observations of tensile specimens showed increase in toughness of bainite-ferrite in comparison to...
Properties of alumina nanoparticle-filled nitrile-butadiene-rubber/ phenolic-resin blend prepared by melt mixing
, Article Polymer Composites ; Volume 30, Issue 9 , 2009 , Pages 1290-1298 ; 02728397 (ISSN) ; Shojaei, A ; Sharif University of Technology
2009
Abstract
Effect of alumina nanoparticle (ANP) on the properties of rubber compounds based on nitrile-butadiene-rub- ber (NBR) and NBR/phenolic-resin (PH) blend is examined. To investigate the surface characteristics of the nanoparticles on the performance of nanoalumina- filled compounds, trimethoxyvinylsilane (MVS) is attached chemically on the surface of ANP through an appropriate functionalization process. Various NBR and NBR/Ph compounds filled with ANP and functionalized ANP (f-ANP) are prepared via melt mixing using traditional open two-roll mill. Microscopic analysis carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveals good dispersion of...
Failure analysis of holding U-bolts of an automobile wheels
, Article Engineering Failure Analysis ; Volume 16, Issue 5 , 2009 , Pages 1442-1447 ; 13506307 (ISSN) ; Etemadi, A. R ; Edris, H ; Sharif University of Technology
2009
Abstract
Holding U-bolts of an automobile wheels are manufactured from 10B21 boron steel rods. Changing the source of the rods from X to Y, with an identical manufacturing procedure, it was observed that parts fracture at the mechanical straightening stage (final stage of the manufacturing line). In this case study, microscopy techniques and mechanical tests were used to identify the cause of this failure. It was shown that higher contents of carbon and boron of the source Y rods promotes precipitation of boron containing carbides along the grain boundaries. These precipitates act as crack nucleation sites and are responsible for the fracture of the parts under the straightening stage stresses. Based...