Sharif Digital Repository

Graphene, the newborn nanomaterial whose unique properties has extensively drawnattention of many scientists in the recent years, is an ideal candidate for sensing applications due to its exclusive properties like extremely high specific surface area, excellent electrical conductivity, andcapability of being easily functionalized. In this research, after reviewing the attempts already performed on detection of DNA, in order to detect the four bases of DNA (G, A, T, and C) via electrochemical approach, graphene nanosheets were synthesized by the popular Hummer’s method and were deposited on a graphite rod by electrophoretic deposition with a vertical preferred orientation. To eliminate the... 

In the past decade, with the expansion of e-commerce, there has been an unprecedented growth in demand for online retailing. Due to this growth, fast, efficient, and flawless delivery of shipments to final customers has become especially important. On the other hand, the expansion of urbanization and the increase in urban traffic have also created obstacles to efficient delivery. These factors have introduced new challenges for logistics service provider companies. Several innovations have been proposed in recent years to address these problems. Delivery of goods to locations such as the trunk-in-car or shared delivery locations like lockers is one of the key innovations in solving logistics... 

Analysis of semen and quality assessments of sperm cells is of great importance in scrutiny of male fertility. Several methods have been introduced for analyzing and identification of the sperm motility and morphology in a semen sample. Identifying and tracking of rapid and variant movements of multiple sperms, in a short duration of time, is somewhat difficult and complex for human, even for an expert. Then applying semi-automated or automated (un-supervised) methods, based on image analysis and computing, spread fast and computer aided semen analyzer systems, became wildly used in clinical and research laboratories.
In this paper we propose an efficient multiple tracking methods to... 

Infertility is an important problem to deal in medicine. In every four couples, on average, one couple is affected by infertility in developing countries. In the majority of cases, the infertility of men has a relationship with spermatozoa and semen, and can be measured by semen and spermatozoa analysis for more advanced diagnosis and treatments. Analysis of the movement patterns of spermatozoa were performed by expert screeners earlier, but nowadays, many of these analyzes are performed using computer-based systems called computer assisted sperm analysis (CASA). The benefits of using CASA instead of expert screeners are achieving system-independency and numerical results at the end of the... 

Design and construction process of special kind of sputter ion pump is described briefly in this paper. In order to investigate the optimization of effective parameters in choosing and designing ILSF ion pumps, this pump has been designed and manufactured. By optimizing some parameters such as dimension and shape of penning cells, anode voltage, magnetic field and internal structure of pump, it is possible to significantly decrease the cost of construction and operation of synchrotron vacuum system. By using the results of simulations and calculations of electromagnetic field, plasma simulation or glow discharge, titanium sputtering, etc., critical parameters in design of internal structure... 

In this thesis a digital electronic readout system is designed and constructed for MWPC detector. This detector is aimed to be used in ILSF synchrotron. The detector readout system is based on delay line and position of incoming photon can be underestood from delay of cathode signals arrivals. The detector has two dimentional position detecting system and the instruments used in every dimention are identical. Every dimention has a start and stop signal, the time difference between these two signals can be detected by time to amplitude converter or time to digital converter. In this thesis time to digital converter has been used and the time diference of start and stop signals arrivals is... 

This research concerns investigating the behavior of two-phase flow in the inlet and outlet of the microchannels.Both the droplet based and the continuous microfluidics are considered. For the continuous system whenthe minor fluid enters the microchannel, due to ratio of viscosity of two fluids, viscous folding occurs.Viscous folding phenomena is similar to the buckling phenomena in solids.This means that the viscosity of the fluid, which is applied to two sides of the fluid layer, causes folding the fluid layer and changing the shape of it. For the study we employ a VOF based numerical routine. In order to verify numerical results, the grid and the time step independenciesare checked. In... 

Trip demand analysis is among the most important parts in comprehensive transportation studies. Developing four stage models including trip generation, trip distribution, mode choice, and assignment are so common in demand analyzing. In this study, trip generation models have been studied and to analyze data, two different methods including OLR and GWR are utilized. This study aims to examine relationship between aggregate zones in order to forecast future trips. Moreover, results of modeling trip generation with two different methods, OLR and GWR, are compared. Comparing different levels of aggregation reveals that as the number of zones decreases, the results get better. Decreasing number...