Sharif Digital Repository

The principle of micromechanics has been used to determine the maximum allowable press-fit for the hip stem during total hip arthroplasty. A 2D parametric solution has been presented. Bone and stem cross sections are modeled parametrically with respect to their geometry and mechanical properties. Surrounding soft tissue is also modeled and all the participating materials are considered as linear isotropic. Drucker-Prager fracture criterion is used to interpret the fracture phenomenon which is considered as both strain- and stress-state fracture. Considering presence of a thin layer of cancellous bone in the model caused a significant increase in results in comparison with previous numerical... 

In this work a new innovative microfluidic system for the selection of motile sperms was developed. The novel aspect of this work is based on the fact the motile sperms follow microchannel walls. Immotile sperms are not able to follow curved paths and therefore their movement toward the outlet gets hindered and most of them could not reach to the outlet. But motile sperms, moving alongside the microchannel walls, reach to the outlet and get separated from the immotile ones. After designing, 3 microfluidic chips having curved microchannels with curvature radius of 150, 300 and 600 micrometer and one with a straight microchannel were fabricated using photolithography and soft lithography.... 

Parkinson's is a disease caused by a disorder in the central nervous system of the body. There is no definite cure for this disease, but one of the ways to prevent the progress of this disease is to use movement therapy. One of the goals of designing wearable systems consisting of inertial sensors is to make it possible to perform this movement therapy from a distance. The purpose of the present study and research is to use the approach of simple and complex activities in order to increase the accuracy in the detection of activities and also to solve the problems of the previous system, with the help of creating the ability to detect complex meaningful activities for Parkinson's patients. In... 

In the recent decades, Polymer Electrolyte Membrane Fuel Cells (PEFC) have been known as an appropriate type of fuel cells, due to being electrochemical converter and clean energy generator with high power density and having low operation temperature and launch time. Palatine is one of the major materials that are used in electro-catalysts of fuel cell. Due to shortage of palatine resources and its high price, fuel cell production is not economical. To achieve economic conditions for production of fuel cell, two major methods are proposed:
1) Reduction of the employed amount of palatine in electro-catalyst
2) Full replacement of palatine with cheap materials
In the current... 

The oxidation-reduction (redox) responsive micelle system is based on a diselenide-containing triblock copolymer, poly(ε-caprolactone)-bis(diselenide-methoxy poly(ethylene glycol)/poly(ethylene glycol)-folate) [PCL-(SeSe-mPEG/PEG-FA)2]. Resulting in the development of tumor-targeted delivery for hydrophobic anticancer drugs. The diselenide bond, as redox-sensitive linkage, was designed, so it is located at the hydrophilic/hydrophobic hinge to allow complete micelles collapse and efficient drug release, in redox environments. The amphiphilic block copolymers self-assembled into micelles at concentrations above the critical micelle concentration (CMC) in an aqueous environment. Dynamic light... 

In this thesis, we give necessary and sufficient conditions for a simplicial com- plex with small codimension to satisfy the Serre’s condition (Sr) as well as the CMt property. We also give a connection between being (Sr) and being CMt. Also, we focus on the dimension of dual modules of local cohomology of Stanley– Reisner rings to obtain a new vector which contains important information on the Serre’s condition (Sr) and the CMt property as well as the depth of Stanley–Reisner rings. We prove some results in this regard including lower bounds for the depth of Stanley–Reisner rings. Further, we give a characterization of (d − 1)-dimensional simplicial complexes with codimension two which are... 

In recent years, the reductive dehalogenation of the chlorinated hydrocarbons using nanoscale zerovalent iron (nZVI) represents a promising approach for underground remediation. Regarding commercialization of this technique, instability and unknown nature of nZVI particle are still challenging tasks that should be considered.
In the current work, Nanoscale zero-valent iron (nZVI) and palladized iron (Pd/Fe) bimetallic particles were synthesized and employed to react with chlorinated compound (PCE) in water to investigate its degradation behaviors. The results show that the reactant ratio, stabilizer amount and temperature are the main parameters with the considerable effect on PCE...