Sharif Digital Repository

Bread, as an essential item in Iranian food menu, is a very sensitive food item in our country. However, the bread types currently produced in the country have a low quality and consequently a high level of losses. The proposed solution for this problem is to change the pattern of bread production from the traditional method to the industrial method. In this research, after designing a feasibility structure, we evaluate the project of building an industrial bread production factory from two technical and financial points of view and estimate total investiment costs and production costs. Then we estimate the sale income and evaluate indexes like net present value, internal rate of return,... 

The problem of PM pollutants has become one of the main environmental concerns of Tehran city due to the growth of city population and industrialization. As a consequence of this problem there is an increasing trend in the number of unhealthy days in Tehran in terms of air quality in recent years. Solving this problem needs strict regulations to limit the amount of pollutants released from vehicles, industries and power plants. To help this cause, this study investigates the effect of emissions and climate change under RCP scenarios on future PM2.5 concentration in Tehran by using WRF-SMOKE-CMAQ modeling system. The result of simulation of climate conditions under RCP8.5 scenario in 2050... 

Vertical turbulent mixing in lakes plays a critical role in the distribution and transfer of nutrients, oxygen, and heat, significantly impacting lake productivity and the growth of algae and aquatic plants. During summer, the persistent and intense solar radiation creates a thermal stratification in lakes, which inhibits deep vertical mixing. In stratified lakes and oceans, small-scale mixing processes are key drivers of vertical fluxes that transport particles and substances, including nutrients, pollutants, and microorganisms. Despite the significant influence of small-scale turbulent mixing, numerical models of stratified lakes often neglect these effects due to the challenges associated... 

The purpose of this research is to investigate the capability of process-oriented modeling and deep learning for monitoring and forecasting the water quality of stratified lakes and to provide a unified framework integrating these two models to improve the monitoring and prediction of water quality. In this thesis, the process-oriented General Ocean Turbulence Model (GOTM) has been developed to simulate the hydrodynamic and thermodynamic processes of Gull Lake from 2008 to 2017. Subsequently, the MLP deep learning model has been employed to study the lake's key water quality indicators during this period. Meteorological data serves as input for the GOTM. Calibration and validation of the... 

High-quality online services demand reliable and fast packet delivery at the network layer. However, clear evidence documents the existence of compromised routers in the ISP and enterprise networks, threatening network availability and reliability. A compromised router can stealthily drop, modify, inject, or delay packets in the forwarding path to launch Denial-of-Service, surveillance, man-in-the-middle attacks, etc. So researches tried to create intrusion detection methods to identify adversarial routers and switches. To this end, data-plane fault localization (FL) aims to identify faulty links and is an effective means of achieving high network availability. FL protocols use... 

Confining nematic liquid crystal between two curved boundary conditions while the nematic molecules have a degenerate planar anchoring leads to complex and beautiful textures of molecular disparagement(defect) in the bulk and on the surfaces. Such the liquid crystal shells are made with double-emulsion techniques in microfluidic devices have provided applications for micro-scale colloidal linkers.In this work, we have numerically minimized the elastic energy in one-constant approximation in present of Fournier’s degenerate surface potential with finite element method. The nematic shell is confined between two spherical surfaces that we have studied the final energies and their related... 

A liquid crystal is a state of matter composed of highly anisotropic building blocks. When liquid crystals are exposed to surfaces with given shapes and anchoring conditions, the orientation of their molecules gets spatially disordered and topological defects may form in the system. The interplay between liquid crystals and the geometry and topology of the colloidal particles has motivated extensive recent studies.In this thesis, we present the numerical modeling results for two faceted colloidal particles in a thermotropic nematic liquid crystal. To obtain the equilibrium nematic field with a finiteelement method, we numerically minimize the free energy of the system that based on the... 

Providing high bandwidth network infrastructures for ever increasing need of data transport is of great importance. The underling infrastructure for many communication services such as GSM/3G/4G mobile networks and Internet services is Synchronous Digital Hierarchy (SDH) optical transport systems. SDH are standardized protocols that multiplex multiple lower rate digital bit streams, such as E1 and Ethernet, and transfer them synchronously over optical fiber using lasers or LEDs. In addition to high data transfer rates, flexible network management and protection mechanisms have great importance, hence are part of SDH standards. In order to obtain flexible network architecture and protected... 

Development of Smart Grid and deployment of smart meters in large scale has raised a lot of concerns regarding customers’ privacy. Consequently, several schemes have been proposed to overcome the above mentioned issue. These schemes mainly rely on data aggregation as a method of protecting users’ privacy from the grid operators. However, the main problem with most of these schemes is the fact that they require a large amount of processing power at the meter side. This, together with the fact that smart meters don’t usually have a powerful processor, can cause the unavailability of smart meter data at the required time for operators of the grid, and at the same time disables smart meters from... 

Secure routing is a major key to service maintenance in wireless ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. Wormhole attack is one of the most severe active attacks to mobile ad hoc networks. Noting the resource limitations in such networks, nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a... 

Due to anthropogenic activities and climate change, Lake Urmia, one of the largest hypersaline lakes, is exposed to desiccating. The increase in salinity in this lake up to more than 400 p.s.u has endangered the ecology of this lake. In this study, a three-dimensional, unstructured grid and finite volume model FVCOM has been developed to investigate Lake Urmia's hydrodynamics, salinity, and water temperature over the year 2016. Some of the model inputs were lake bathymetry, meteorological data (including air temperature and pressure, wind speed and direction, short-wave and longwave radiation), precipitation, evaporation, river flux, salinity, and temperature. The model was calibrated... 

Dynamic spectrum access with the aid of cognitive radio (CR) technology is a viable solution to spectrum scarcity. There are many military and emergency applications that require the use of cognitive radio ad-hoc networks (CRAHNs). In these net- works, nodes must first find each other in a wide spectrum and then exchange their desired data. The process of finding each other in a multichannel environment is a challenging task and is usually known as rendezvous. Since rendezvous is the first step in communication, disrupting will disable the nodes from establishing proper communication sessions. That results in a drastic degrade in the performance of the network. Therefore, it is important to... 

Spray-wall impingement is one of the phenomenon that associated in different subject such as spray cooling, combustion chamber and gas turbine. With the impingement of spray to the wall, liquid film begins to form. Wall film characteristics is still an important subject to study. Due to the various stages of liquid film formation from injection of spray till spray-wall impingement, the investigation of this phenomenon is far more complicated. This paper is meant to provide detailed data on spray-wall impingement and wall film formation physics with the help of computational analysis of OpenFOAM . A Lagrangian-Eulerian method based on discrete phase model (DPM) was employed to model... 

Light propagation through turbid media, such as biological tissues, experience scattering due to inhomogeneous distribution of refractive indices of their microscopic structure. Scattering and diffusion of light not only limit many optical imaging techniques, but are also big challenges for telecommunication, spectroscopy, and other optical techniques. Recently many new imaging methods are developed that work in strongly scattering media such as optical coherence tomography, diffusion tomography, and laser speckle velocimetry. In this thesis, we have studied how wavefront shaping techniques can tackle the problem of scattering. By spatially shaping the wavefront of the incident beam, using... 

Nowadays, because of the importance of saving energy resources and also environmental issues, utilization of catalysts are increased in industry and products. In the last decades, a lot of efforts have been devoted to develop novel methods for heterogenizing of the homogeneous catalyst in order to combine the advantages of the both the homogeneous and the heterogeneous catalysts. Among the different solid supports, graphene with high surface area and distinctive mechanical and electronical properties have been introduces as an emerging support for heterogenizing of the homogeneous catalysts. On the other hand, the use of ionic liquid has been developed due to a broad range of polarity, low... 

Wetlands are valuable ecosystems that have a wide variety of functions to protect biodiversity, natural, economic and social values. Hydrological changes and nutrient enrichment, resulting from population growth, economic development and climate change are threatening the wetlands. Recently, assessing spatial and temporal variations of water quality has become an important aspect of the physical and chemical characterization of aquatic environments. Anzali wetland is one of the international wetlands in Iran, located in the southern part of the Caspian Sea in Gilan province. This wetland has been exposed to many pollution sources including agricultural, industrial, and municipal wastewater...