Sharif Digital Repository

Bioorthogonal chemistry defines any reaction, inside or outside the living systems, without interfering with native chemical processes and 3dimensional structure of proteins. In these types of reactions water is the sole solvent; a neutral pH is required; the temperature must be up to 40 oC. The kinetics of reactions must be on the hour scale and the nontoxic reagents with low concentration must be used. One of the simplest methods of visualizing protein molecule is covalent attachment of fluorescein to protein. In this work several fluorescent compounds were synthesized. These novel compounds include acylchloride fluorescein, N-hydroxysuccinimide fluorescein, thiophenol fluorescein, and... 

In this study in-situ Al/Al3Ti was fabricated by mechanical alloying, hot extrusion and subsequent heat treatment. First, initial pure powders of Al and Ti were mechanically alloyed with 5 weight percentages of Ti for 40 hours. The as-hot extruded samples containing 5 wt% of initial Ti particles, were exposed to heating at 600 oC for various time intervals up to 10 hours. Microstructure analysis by OM and SEM proved that in-situ Al3Ti phase was formed as a layer around Ti particles by solid reactive diffusion between Al and Ti particles. After 10 hours of heating, all the Ti particles were consumed and transformed to Al3Ti. Mechanical properties of samples were investigated by Brinell... 

Traditional multi-level SRAM-based cache hierarchies, especially in the context of chip multiprocessors (CMPs), present many challenges in area requirements, power consumption, and design complexity. STT-RAM has received increasing attention because of its attractive features:good scalability, zero standby power, non-volatility and radiation hardness. The use of STT-RAM technology in the last level on-chip caches has been proposed as it minimizes cache leakage power with technology scaling down. Furthermore, the cell area of STT-RAM is only 1/4 that of SRAM. This allows for a much larger cache with the same die footprint, improving overall system... 

Nowdays, it has been shown that protein misfolding is involved in more than forty diseases including Alzheimer’s and Parkinson’s. Alzheimer’s disease is one of the most common neurodegenerative diseases that disrupts brain function. The main cause of this illness is due to formation of extracellular amyloid plaque from a 42-amino acid-peptide called amyloid beta. Amyloidosis is caused by missfolding of peptides and proteins mainly because of physical and chemical changes in biomolecule or their environment.
Therefore, in this dissertation, using synthetic and recombinant abeta peptide, kinetic of amyloidosis was examined. Ultrasmall peptides (three-amino acid), containing branched chain... 

Online advertisements have captured a major part of websites and mobile applications nowadays. In this kind of advertisements, as soon as a user interacts with a website or a mobile application, we have to decide which ad to show in a fraction of a second. In online advertising systems, revenue increases only when a user clicks on an ad banner or when they interact with the ad. So in order to select the best (most profitable) ad banner, the probability of clicking on or interacting with the ad banner must be estimated and then the most profitable ad will be selected.So one of the most essential problems in online display advertising, is estimating the probability of the click on a certain... 

To create applications for smart environments we can select from a huge variety of sensors that measure environmental parameters within the premises. Capacitive proximity sensors use weak electric fields to recognize conductive objects, such as the human body. They can be unobtrusively applied or even provide information when hidden from view which make these sensor more popular. Furthermore, these sensors are low cost, precise and low power. In this thesis, we study the construction and operation of capacitive sensors and the challenges of using them. Then we use them to produce smart devices. Smart flooring is used on the ground and it can be used to track people or fall detection. Smart... 

In this research, a review on fluoride adsorption revealed that the modification of the adsorber surface with ions like Ca2+ results in great enhancement of the fluoride adsorption. It seems that the enhancement in fluoride adsorption by the modified adsorber, is mainly due to the selective chemical binding of the fluoride ion with the surface-bound ion (Ca2+), regardless of the base material itself. In order to confirm this hypothesis, two different adsorber materials namely, γ-alumina (a material, conventionally used for fluoride removal from water and wastewater) and Micro-silica (a mineral with small adsorption capacity for fluoride) were selected for further study. It was found that the... 

In past decades, we have seen the rise of integration density in chips making it possible to design a whole system on a single chip. The previously designed interconnection architectures for multiprocessors systems cannot directly be applied in on-chip systems (especially when the number of processor elements increases) since they require a different type of a cost-performance trade-off. This is why the interconnection networks of systems-on-chip (SoC) are such a problem. Network-on-chip (NoC) was being proposed as a scalable and reusable communication platform for SoCs, which makes use of the network model to develop efficient on-chip communication infrastructures. The NoC has a layered and... 

Hyperscale cloud data center (HCDC) (a.k.a., hyperscale data center) is the backbone of a wide variety of Internet services such as web-hosting, ecommerce, social networking, software as a service (SaaS), platform as a service (PaaS), application as a service (AaaS), and cloud computing.HCDC platforms consist of massive parallel processing, high utilization rate, and high volume storage that cost hundreds of million dollars.The increased demand for various Internet services and the subsequent dramatic growth in HCDC platforms, have caused an exponential increase in utilization of energy. With energy costs on the rise and global attention focused on carbon footprints, organizations are... 

This thesis represents the obstacle avoidance of a fixed-wing small aircraft using optical flow information of cameras mounted on the aircraft. The thesis consists of two main sections. In section one, the ideal optical flow has been simulated based on the camera model, complete six DOF of flight equations, and the geometry of the environment. An analytical formula has been derived to relate the obstacle detection distance to the maneuverability of the aircraft. Having the obstacle detection distance, the control and navigation algorithms have been developed to achieve a collision-free flight for the aircraft in urban canyons and junctions. The effect of some parameters such as approach...