Sharif Digital Repository

Apatite-coated Ag/AgBr/TiO2 was prepared by deposition of Ag as noble metal to generate electron-hole pairs by extending the excitation wavelength to visible light region, AgBr as photo-sensitizer to increasing yield of photo catalyst, and apatite as adsorption bio ceramic for adsorbing pollutants and micro organisms respectively. The bactericidal experiments in dark media indicated that only novel catalyst show inhibiting growth of bacteria. In this case Transmission electron microscopy image illustrated that catalyst nano particles adhere to the outer membrane of the cell and acts as inhibitor to nourish of bacteria from around media. The mechanism for deactivation E-Coli and B.Sub in the... 

Let G be a graph with adjacency matrix A and Δ be a diagonal matrix whose diagonal entries are the degree sequence of G. Then the matrices L = Δ− A and Q = Δ+A are called Laplacian matrix and signless Laplacian matrix of G, respectively. The eigenvalues of A, L, and Q are arranged decreasingly and denoted by λ1 ≥ · · · ≥ λn, μ1 ≥ · · · ≥ μn ≥ 0, and q1 ≥ · · · ≥ qn ≥ 0, respectively. The energy of a graph G is defined as E(G) :=
n
i=1
|λi|.
Furthermore, the incidence energy, the signed incidence energy, and the H¨uckel energy of G are
defined as
IE(G) :=
n
i=1
√
qi, LE(G) :=
n
i=1
√
μi, HE(G) :=

2
r
i=1 λi, n=... 

A traffic classifier maps each input stream into a pre-defined traffic class. If the traffic is encrypted using a protocol, such as SSL, or is protected using an encrypted tunnel, it's content would be hidden from the classifier, in which case the common traffic classification methods will be ineffective. Although common security mechanisms which provide information confidentiality to user can't hide all properties of messages, including length and time. Some of the newly presented methods of traffic classification utilize these properties and can actually classify messages without accessing their content. We will study such methods and their limitations in this thesis. Of all the encrypted... 

Drilling Operations constitute more than fifty percent of total costs of well construction operations. Due to this fact, optimization of drilling operations could have significant effect on decrease in total costs of well construction. It is mentioning worthy that there are a variety of parameters which affect drilling operations from the view point of optimization. In many cases several of those aforementioned parameters are contrary in nature. Thus obtaining an integrated approach to optimize the operation by considering these effects is necessity. The goal of this thesis is to investigate different influential parameters of drilling operation optimization and to develop computer-based... 

Scale formation is an unpleasant phenomenon that occurs when the mixed fluids are incompatible. The scales damage the reservoir, wellbore and the surface facilities. They reduce the effective fluid path and increase the pressure drop of the system; so it is necessary to study the precipitation thermodynamics of scale formation, and present a trustable method for banning the scales from precipitation. In this project, it has been tried to study the value of precipitated scale due to the mixing of two incompatible waters (Civand and Sea Water). The results of which are compared with the results of a geochemical software named PHREEQC. Then, the performance of hydro chloridric acid as a scale... 

We report on numerical and intelligent modeling of three-dimensional laminar flow of non-Newtonian fluids driven by axial pressure gradient in annular media consisting of a coaxially rotating inner cylinder. This is an example of a rotating Couette flow with vast applications in food, oil and gas, and chemical engineering industries. We study the dynamics of pressure in and the velocities (in three directions X, Y and Z) of every grid in presence of rotation and without that by means of CFD. Afterward, we develop a novel predictive model based on an Artificial Neural Network (ANN). The hybrid ANN framework is trained and tested by over 100000 data which collected by CFD. We then perform... 

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.... 

In this dissertation, we introduced a Fuzzy based representation and comparison method for sequential patterns such as speech and online handwriting. The new model, called Fuzzy Elastic Matching Machine (FEMM), is simpler than traditional HMM based approaches and is not based on the common statistical assumptions of HMM systems. The model was tested on isolated word and phoneme recognition tasks in speech recognition domain and isolated letter recognition in Persian handwriting recognition. We showed that this method is faster than traditional HMM based models and more robust to noise. To train the model, we introduced a Symbiogenesis-based evolutionary training algorithm. This algorithm... 

In recent years, unmanned vehicles have intensively been developed to reduce human dangers for marine applications. Predicting the hydrodynamic coefficients of an autonomous underwater vehicle is important during the vehicle’s design phase. In other words to design an AUV, one must clarify its maneuverability and controllability based on a mathematical model. The mathematical model contains various hydrodynamic forces and moments expressed collectively in terms of hydrodynamic coefficients. Therefore, the correct values of the coefficients must be known to precisely design the controller of AUVs.SUT-2 is an AUV, being developed by Marine Engineering Laboratory of Sharif University of... 

Most of the current application and potential FGM included in the areas related to contact mechanic .These issues essentially are related to the transfer of force between two objects, that in general is with friction, so in this study the contact under the loading of horizontal and vertical with its different aspect such as the effect of contact region, the effect of round and also the effect of getting harden and soften of FGM.
The used method is a numerical method ¬(finite element method) that will resulted in contact equation discretisce by use of Penalty method. In this thesis is also presented the needed algorithms for solving the problem and the finite element code for solving the...