Sharif Digital Repository

The issue of automation has always been a concern for humans over the years. Replacing humans with machines or intelligent software to perform various tasks can significantly improve the accuracy and speed of those activities. One of the long-standing aspirations of humanity has been the automation of driving. In addition to freeing individuals from the time-consuming task of driving, automating vehicles can also dramatically reduce road accidents. To achieve this goal, vehicles need to be equipped with various sensors such as radar, cameras, lidar, and more. Each of these sensors has its advantages and disadvantages, and as a result, all of them must be used for safe driving. In this... 

Superparamagnetic core/shell nonporous (S1) and core/shell/shell mesoporous (S2 and S3) nanocomposite magnetite/silica particles with a magnetite cluster core of 130±30 nm, a nonporous silica shell of 90±10 nm thickness, and a mesoporous silica shell of 70±15 nm thickness were prepared thorough a simple method. Mesoporous particles were prepared with two BJH pore sizes (2.44 for S2 and 3.76 nm for S3 particles, respectively). The fabricated S1, S2 and S3 particles present high saturation magnetization values of 20, 13 and 17 emu/g, respectively. As a biological application, the lipase from Pseudomonas cepacia was successfully immobilized onto the amino-functionalized nanocomposite particles... 

In this project a knee prostheses wear testing simulator based on a parallel mechanism for applying forces and torques, is designed. First according to ISO 14243 standard required degrees of freedom and design constraints are determined and also regarding simulator requirements some considerations in design are outlined. Considering all of these parameters, literature has been searched for proper parallel mechanism and because no suitable parallel mechanism, which is a 3 DoF 2T1R paralle mechanism with rotational degree about z axis, has been found; several new designs of proper mechanism have been presented. Scoring different mechanisms according to outcomed parameters from standard and... 

Fighting contagious microbial diseases is considered a serious health issue, which has attracted much attention in worldwide. Thus, development of new materials based on nanostructures as a new generation of antibiotics to address this challenge has been of interest to researchers in recent years. Nanostructures based on metallic oxide semiconductors such as oxides with light absorption, production of electron-hole pairs in needle like structures cause tearing bacterial membrane and eventually destroy the bacterium. To this end, we designed experiments to study mechanism and physics governing the process of bacterial degradation to determine the best conditions for inhibiting bacteria... 

Oscillators are an important building block in the design of synthesizers for RF system applications. State-of-the-art operation defines that an oscillator should have the best spectral purity while consuming a low amount of power. In recent years, several methods have been presented for reducing phase noise separately in the 1/f2 and 1/f3 regions. As CMOS technology advances, the amount of power supplies decreases, which worsens the inherent flicker noise. In this thesis, it has been tried, while investigating the existing methods in the phase noise in this region, it presents the proposed oscillator which is based on a three-coupled transformer. This voltage bias oscillator operates at a... 

Approximately 1.36 billion people worldwide suffer from sleep apnea, necessitating accurate diagnosis and treatment. Traditional sleep clinics rely on Polysomnography (PSG)-based monitoring devices. However, these devices are not only voluminous but also prohibitively expensive, requiring numerous sensors and wires that disrupt sleep and cause discomfort for patients. To address these challenges, we have developed a wireless wearable system. This system comprises three sensor blocks, each capable of capturing vital signs from the body, resulting in a total of eight signals. The first two sensor blocks capture signals from the body, which are subsequently modulated and transmitted to a user's... 

The continuous growth of network traffic and people's demand for higher data rates, have driven wireline communication systems towards higher data rates. In these systems, the power consumption of these transmitters and receivers is a crucial and influential factor. This paper presents two different solutions to reduce the power consumption and area of these systems. In the first solution, a low-power phase shifter with variable phase and amplitude control is introduced. The changes in these parameters are mutually orthogonal, ensuring that a change in one characteristic does not affect the others. This phase shifter can be used to generate clock pulses with different phases in wireline... 

Cancer is an abnormal growth of cells which is one of the major cause of worldwide’s mortality. Circulating Tumor Cells (CTCs) are rare cancer cells released from the primary or metastatic tumors and transported though the peripheral circulatory system and spreads in body and seize healthy organs. Early detection of CTCs can help in overtaking the cancer, hence isolation of CTCs is an essential step for many therapeutics. In spite of its clinical potential, the isolation and detection of CTCs has been a challenging task due to its rare presence amongst other blood cells (as low as 1–10 CTCs per billions of blood cells), similarity to white blood cell in size and also variability in terms of... 

The use of hyperspectral images to detect food fraud has become popular and it is necessary to develop chemometrics methods for analyzing the data from these images. Additionally, food authenticity has become a major challenge, and the focus of this thesis is on developing multivariate methods in chemometrics to extract useful information from data obtained from food authenticity verification using hyperspectral imaging (HSI). This thesis consists of six chapters. In the first chapter, a brief introduction to the fundamentals of hyperspectral imaging and food authenticity verification is presented. In the second chapter, the data structure of these images and chemometric methods including... 

In recent years membrane bioreactors (MBR) were widely used as an advanced process for industrial wastewater treatment. But fouling issue causes some restrictions in these systems. So for fouling reduction many researches were done.In this study for fouling improvement, blending of hydrophilic polymer (PAN) with main polymer PVDF was used. Blending membrane in phase inversion process with DMAC as solvent and water as non-solvent was made. For pore-forming in membranes, PVP as hydrophilic additive with three different composition was added and then for more enhancement of antifouling property of membrane, TiO2 nanoparticles with four different composition were added to polymeric... 

This projct includes the following sections: In the first section, Michael addition reaction of anthrone to nitroolefins is described in water without using any catalyst to prepare 9-(2-nitro-1-arylethyl)anthracene-10(9H)-ones. This method is green, efficient and gives high yields of products. The solvent effect is also investigated. In the second section, Considerable efforts have been directed in recent years towards the transition metal complex catalyzed oxidation of organic compounds such as olefins, sulfides, benzylics alcohols and phenolics. And due to the various advantages of supported heterogeneous catalysts and in our aim to develop a simple, more efficient and eco-friendly... 

In this research, we have tried to predict the morphology of the membranes that were prepared by phase inversion method. In this research Polyvinylinedifluoride (PVDF) and dimethylacetamide (DMAc) was used as the polymer and solvent. The affect of titanium oxide (TiO2 ) and polyvinylpyrolidene (PVP) which are respectively an inorganic and an organic additive, on the morphology of the membranes was investigated. Ternary and Quadratic phase diagrams were drawn based on the Flory Huggins theory. The interaction between components was determined and the effect of interactions and molar volumes of polymer, solvent, non-solvent and additives on the binodal line was investigated. To predict... 

We present a deep neural network to classify dermatological disease from patient images. Using self-supervised learning method we have utilized large amount of unlabeled data. We have pre-trained our model on 27000 dermoscopic images gathered from razi hospital, the best dermatological hospital in Iran, along with 33000 images from ISIC 2020 dataset. We have evaluated our model performance in semi-supervised and transfer learning approaches. Our experiments show that using this approach can improve model accuracy and PRC up to 20 percent on semi-supervised setting. The results also show that pretraining can improve classification PRC up to 20 percent on transfer learning task on HAM10000... 

Genetic heterogeneity within a tumor, which occurs during cancer evolution, is one of the reasons for treatment failure and increased chances of drug resistance. Cancer cells initially derive from a mutated progenitor cell, resulting in shared mutated genes. Throughout the course of tumor formation and progression, the occurrence of new mutations is possible, leading to the generation of cancer cells with various mutated genes. An appropriate approach is to identify the sequence of mutations that have occurred in the tumor, which can be inferred from single-cell sequencing data. Singlecell data provides valuable information about branching events in the evolution of a cancerous tumor. In...