Sharif Digital Repository

Polymeric membranes are widely used these days for wastewater treatment applications, but they still have some disadvantages due to their hydrophobicity. In this study, a novel chitosan (CTS)-grafted metal-organic framework (UiO-66-CTS MOF) was synthesized and used as a stable filler in a polysulfone (PSF) matrix to enhance the hydrophilicity of resulting mixed matrix membranes (MMMs) and prevent nanoparticle agglomeration. CTS was grafted onto UiO-66-NH2 via a Schiff-base reaction, utilizing glutaraldehyde (GA) as a linker due to the presence of amino groups in both components. The successful synthesis of MOFs was confirmed by various characterization techniques, with the results... 

Keyword spotting with high speed and accuracy is an important subject whithin speech processing domain especially when we are dealing with various transmission channels. In this research discriminative keyword spotting methods are compared with HMM-based approaches. We have employed the discriminative approaches as our baseline methods due to their higher accuracy. The drawback of the conventional discriminative methods is their high computation cost and long execution time. The discriminative approach consists of two steps: feature extraction and classification. We have proposed four ideas to improve the performance of the baseline method. To improve the speed of the process, in feature... 

Atmospheric corrosion as one of the most principal factors of destruction is not Climatic map of atmospheric corrosion is closely related to air and atmospheric factors among which we can point out to different types of atmospheric pollutions such as NOX, SOX gases and pendant materials as well as the rate of humidity and rain and even the rate of sun radiation. The effects of these factors beside each other cause the speed of corrosion from a climate to another climate to be changed, which is presentable in form of a map. There is a 2 method to provide this map. First build up a station to measure the corrosion data and collect them in a long period of time. This method are time consuming... 

Plasma electrolytic oxidation (PEO) is an advanced technique for creating composite/ceramic coatings on lightweight metals such as aluminum, magnesium, and titanium. This study aims to enhance the corrosion resistance of 5052 aluminum alloy by applying a PEO coating incorporating titanium dioxide (TiO₂) nanoparticles. Initially, samples were coated in a silicate-based electrolyte bath (containing 10 g/L sodium metasilicate and 2 g/L potassium hydroxide) at different processing times (5, 10, and 15 minutes) and current densities (0.2, 0.3, 0.4, and 0.5 A/cm²) to determine the optimal coating conditions. Once the optimal parameters were identified, TiO₂ nanoparticles were added to the... 

This research presents a new harmonic model for compact fluorescent lamps and other nonlinear loads. In recent years, nonlinear loads have gained widespread acceptance due to their characteristics. Although CFLs consume less energy, they draw extremely distorted current waveforms resulting in harmonic losses in distribution networks. The presented harmonic Norton models in this work are simple and accurate models which can consider the impact of supply voltage harmonics as well. The parameters of non linear appliances model are determined based on measurements. The characteristics of the proposed models make it suitable for analyzing the impacts of large number of CFLs or other non-linear... 

Frank Jackson’s knowledge argument is presented to show the falsity of physicalism. The argument is based on a famous thought experiment according which, Mary, a genius scientist who has spent her whole life investigating the neurophysiology of vision in a black-and-white environment, in spite of acquiring complete physical knowledge in that field, knows nothing about the phenomenological properties of seeing red. The knowledge argument has three main steps: proofing the existence of an epistemic gap, inferring an ontological gap from the epistemic gap and inferring the falsity of physicalism from the ontological gap. Different criticisms are made of each step. One of the criticisms of the... 

The goal of this research is to obtain optimal toll for saveh-salafchegan, Tehran-pardis and Ghazvin-karaj highways. To obtain optimal toll, Small and Yan value pricing model was extended and then parametrs of the model was estimated by using daily data of Maintenance and road transport Organization, then value of time parameter was structurally estimated and optimall toll was numerically obtained for the highways. Finally sensitivity analysis was performed for all parameters. Results show that optimall toll for saveh-salafchegan highway is unique and respectively, are in interval τ≤0.03 and τ≤3.72 . Magnitude of value of time of road users and difference between value of time of users... 

The problem of quadrotors formation flying via optimal approach is investigated using the idea of cooperative and multi-level control. In this respect, a low level optimal control formulation of quadrotors is formulated for stability and tracking where the required tracking commands are generated via the high level controller over a simpler translational dynamics of quads. The idea of multi-level controllers enables one to develop formation keeping controls for complex dynamics systems, where varying agents in terms of dynamics and platform could be utilized. Due to inherent difficulties in implementing acceleration commands emanated out of the high level controller, an inverse dynamic... 

Gas injection is one of the common methods for enhance oil recovery from oil reservoirs. At miscible injection condition, the efficiency of the process is majorly affected by the molecular diffusion coefficient of the gas in the oil. Therefore, the accurate value of this coefficient is an essential for applying in reservoir simulator. However, determination of this coefficient only is possible through experimental methods. In this study, pressure decay method was applied to determine the diffusion coefficient of nitrogen, methane and carbon dioxide gases in crude oil. The reasons for choosing this method are : accuracy in designing the experiment, covering a wide range of pressure... 

The purpose of this research is to monitor the health of structures using the updated finite element model, in which digital images are used to optimize the numerical model. Structural Health Monitoring (SHM) is always an important and significant issue that has attracted the attention of many researchers in recent years. In general, some researches have been conducted in this field using physical sensors that provide discrete data to the system for analysis. Using cameras to monitor the structure makes it possible to extract continuous and integrated data from the structure using digital images, which is a significant advantage compared to physical sensors.In this research, a steel... 

Aluminum Bronzes have many applications in marine environments. These alloys suffer from both hot cracking and cold cracking. In order to overcome the hot cracking and cold cracking, Semisolid Stir Joining method and a proper thermal cycle was used respectively. Effects of temperature, stirring rate, and tool type were investigated in Semisolid Stir joining method. In this method, butt joint design was used in order to place specimens, and the specimens were heated up to specific temperatures (920, 925, 930°C). A stirrer (Cylindrical and Grooved tool) with three rotational speeds (800, 1200, 1600 RPM) was introduced into the stir weld seam. Welded specimens were cooled to the 900°C... 

Nowadays, one of the problems of network designers and users is the correctness of network equipment functionality. Since routers play an important role in information transfer between various networks and communicate with each other through a routing protocol, any violation of such protocol can result in the network's failure or defective transfer of data. Thus, being assured of the conformance of the implemented protocol in a router with what has been defined in the protocol's standard is of great significance. To this end, before using or exposing a router, network equipment testers should run protocol conformance tests on it and insure its correct functionality. This brings up the... 

In order to increase the network performance, to discover network security threats, to guarantee the quality of services, to simulate networks and develop new network protocols, network designers and operators need software tools to analyze the network traffic. The first step to do this analysis is network monitoring. This can be done by using various software and hardware tools.
In this research we developed a tool which analyzes the network traffic using appropriate statistical methods. The models which are analyzed in this application are: Poisson, Self-similar and Weibull. This application analyzes the network traffic based on this statistical models and calculates their parameters.... 

The increasing number of road accidents and fatalities have yielded the introduction of several solutions by related industries such as automobile manufacture. Proposed solutions can be classified into two categories: passive, such as airbags, and active such as ABS ad ITS-based technologies. Inter vehicles communication let the communication between vehicles(V2V) or between vehicles and road infrastructure (V2I) by relying on DSRC technology and standards. Intelligent Transportation System (ITS) has three main types of applications namely safety, traffic and commercial. Safety applications are the main goal of vehicular communication, and real time guarantee in safety applications is so... 

In real-time systems, jobs that miss their deadline are considered worthless or ineffective. Nowadays, real-time applications (such as multimedia) that communicate through software-defined networks (SDN) are widely used and will continue to expand in the future. SDN is an emerging network architecture in which control plane is separated from data plane to manage it directly. In this research, we make changes to the controller and the switch used in such network to deliver real time packets or real-time flows (such as video) on time, as much as possible. As missed deadline packets are worthless and they waste bandwidth, dropping them is a solution. Moreover, the controller can drop flows that...