Sharif Digital Repository

In this project, Fe3O4 magnetic nanoparticles were prepared by co-precipitation method. For protecting them against oxidation and also avoiding from direct contact between core and additional materials that probably makes unwanted reactions, the surface of nanoparticles were coated by SiO2 layer. Being easy to modify and having the control of interactions between nanoparticles are the advantages of coating nanoparticles with silica. The obtained Fe3O4@SiO2 core-shell nanoparticles were covered by two types of polymer (PPG and PEG). The basis of the composite was characterized by VSM, TGA, SEM, XRD, and FT-IR analytical methods.
The antibacterial activities of Copper, Silver and Gold... 

Ag / AgCl /TiO2 , 2 Ap / Ag / AgCl /TiO , 2 AgI /TiO and 2 Ap / AgI /TiO were prepared by the deposition-precipitation method on 2TiO (P25) nanoparticles and their photocatalyctic activities have been investigated under visible light and dark environments. Cationic surfactant plus 2 PVPI (topical solution and dry powder) as an iodine ion source and nonionic surfactant plus KI as an iodide ion source were used to prepar 2 AgI /TiO . In less than 30 minutes, 2 AgI /TiO which has been resulted from combination of cationic surfactant and 2 PVPI showed high efficiency on Escherichia coli under visible light when small quantities of it is used . However, AgCl sample prepared with cationic... 

Behran Mehr Peyma (BMP) is an elevator equipment producer and trader in Iran which was established in 2004. At first they are producing some regular parts of elevator and then during these years they are trying to improve their work and expand their business till they have the 15% market share in elevator market in Tehran.In this thesis I am trying to use the SWOT and PETS methods to show the exact situation of BMP comparing to the whole market considering the competitors.During this reduction in the market I suggest to BMP to change some policies and use some of its strength to attract some new customers, changing their brand name and find a relation to contribute in some tenders and... 

Medical needle interventions are a common technique for accessing tissue structures.In these procedures, needles are used, for example, to extract biopsy samples, brachytherapy, and to insert drugs. In TRUS guided prostate brachytherapy application, Physicians used ulterasound imaging to steer the needle and insert radioactive seeds into cancerous tumors to irradiate surrounding tissue over several months. Prostate rotation, deformation, and unavailability of imaging data during part of the insertion path result in misplaced seeds. To overcome these problems, in this research, we modeled the prostate, its membrane and the surrounding fatty tissue as linearly elastic homogenous material, and... 

This study has investigated the effects of different environmental conditions on the bond at the interface between two fiber reinforced polymer (FRP) layers. A total of 945 single lap splice coupons with three bond length were made using wet lay-up technic. There were used three unidirectional fabrics and one type of epoxy resin. A Uniaxial tensile test was performed on samples after 2, 4, 12, 20, 28, 36 and 48 weeks of exposure. Also series of test were conducted in order to determine the minimum lap splice length of single splice FRP samples. The experimental results indicated reduction of bond strength in glass specimens that was 17 % after 48 weeks of exposure while for same amount of... 

Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. The goal of cartilage tissue engineering is to design a scaffold with proper pore structure and similar mechanical properties to the native tissue. In this study Porous scaffolds prepared from silk fibroin, chitosan and gelatin blends with varying ratio of silk fibroin and gelatin by freeze drying method were characterized for physicochemical, mechanical and biological properties. Among the... 

Deep learning, as a subdivision of machine learning, attempts to model high-level concepts by using a deep graph, consisting of several layers of linear and nonlinear transformations. Implementing these algorithms on hardware is a big challenge.¬This project offers a system in which various hardware methodologies can be used to implement deep learning algorithms side by side. The overall structure of the system consists of high-level programming interfaces for implementation and expression of machine learning algorithms by the user, which will be available as libraries in a high-level programming language such as Python, Ruby, and Julia. These interfaces allow the user to evaluate their... 

Trip distribution is the second step of the four-step travel demand modeling. Like other travel demand models, the most important objective of trip distribution models generation is forecasting the travel data of a year in the future. On the one hand, extensive changes in cities’ urban structures and people’s travel behavior during the years brings up the essential question of how temporally stable and transferable trip distribution models are? This question becomes even more important when the more complex structure of trip distribution models compared to models such as trip generation is considered. On the other hand, it is logical to assume that the consideration of the effects of urban... 

According to studies, low back pain is one of the most common and costly musculoskeletal disorders. Herniation of intervertebral discs exerts pressure on the nerves, causing pain. To alleviate this, physicians perform a procedure called nucleotomy, which removes the disc's nucleus pulposus to reduce pressure, retract the disc, and relieve pain. Accurate estimation of spinal forces during activities is essential for injury prevention, activity correction, and improved surgical techniques. Although laboratory studies on humans or cadavers are valid, they are often invasive and limited to simple scenarios, necessitating precise computational models for comprehensive biomechanical analysis.... 

Storage is well-known as the performance bottleneck in I/O intensive programs such as online transaction processing applications; thus designing a cost-effective high performance disk subsystem is a major concern in enterprise applications. Data tiering is an efficient way to optimize cost, performance, and reliability in storage servers. With the promising advantages of Solid State Drives (SSDs) over Hard Disk Drives (HDDs) such as lower power consumption and higher performance , traditional data tiering techniques should be revisited in order to use SSDs in a more efficient way. This thesis presents a data tiering technique at the Operating System (OS) level to enhance system performance... 

Integral abutment bridges (IABs) are bridges in which the deck is cast monolithically with abutment backwalls. These bridges are also jointless through deck length, due to which they act as a frame in their longitudinal direction. These differences with common seat-type bridge construction, have made IABs more economical to build and maintain and superior in seismic performance. As such, in various countries, this method of construction have been prescribed whenever possible. As an instance, integral construction is mandatory for bridges up to 60 meters in total length in England. IABs have become more of a geotechnical problem rather than simple structural problem of conventional bridges in...