Sharif Digital Repository

This thesis presents the results of the performance of a novel technology called submerged membrane electro-bioreactor (SMEBR). The SMEBR treats wastewater by combining membrane filtration, electrokinetic phenomena, and biological processes in one reactor, and improves treatment performance while helping to control membrane fouling. The newly designed SMEBR system was based on applying an intermittent direct current (DC) field between immersed perforated electrodes around a membrane filtration module. The SMEBR system significantly reduced the fouling rate when iron worked as electrodes and an intermittent DC with an operational different mode was applied.
In Phase 1 of this project,... 

The tolerance stack-up in mechanical assemblies is closely related to the quality of finished products and to the costs of production. In practice, choosing a large tolerance range will result in performance reduction. On the other hand, with small tolerances considered, production costs will increase. Tolerance allocation is a useful tool to control the dimensional and geometric variables of the product, so design engineers can control the final product quality level, production cost, and other variables. The proposed method for tolerance design considers the effects of degradation and quality loss over time and allocates tolerances so that, the functional key characteristic satisfies, as... 

The capability to control and maintain upright posture is a fundamental requirement for humanoid robots. Although many control algorithms were successfully presented, it seems developing a new controller inspired from human balance strategy would greatly improve performance and reduce energy consumption. To study the control strategy used by human nerves system more precisely, a balancing exercise was designed and implemented. Five human subjects were asked to stand on an unstable tilting board and balance the board. Instantaneous Eulerian angles of body segments of human subjects were captured by utilizing Xsense orientation sensors. A humanoid robot standing on the tilting board was... 

Metal sheets are widely used in different industries such as ship building and pressure vessels. One of the most important things in these industries is to create the desired sheets through line heating process. Designing the heating lines in order to get the desired shape with the sufficient accuracy has always been a concern for the engineers in this process. In this research, different methods of designing the heating lines for creating special surfaces are discussed. By integrating the two algorithms called distance based criterion method and angle based criterion method in MATLAB, the heating path and its parameters are defined. These two algorithms can be used in order to predict the... 

Image inpainting is the process of reconstructing lost parts of damaged images based on collected local information, or even general information, as prior knowledge. The image inpainting’s objective is to improve the damaged images, for example restoring missing pixels caused by folding, erasing background’s text in an image, removing watermarks from an image, or editing an image such as eliminating an object or a person from the image. The majority of the image inpainting algorithms approaches the problem by signal restoration from remaining samples or iterative methods to complete the damaged images. Algorithms based on samples, algorithms based on partial differential equations, and... 

Application of canard next to the wing have been widely used in military industry for decades. Although it’s most application is in supersonic flying objects, It has to do it’s duty in lower air speeds too. The aim of this study was to investigate the influence on the wing due to the presence of canard in supersonic flow regime. But because of the importance of the issue, significant attempts has been conducted in subsonic flow regime. High research volume, Absence of a comprehensive theory in this branch and the local defense industry demand as a developing country on the other hand, delivers the importance and applicability of the subject. Another issue of importance is that the... 

Using field assisted dissociation model and with a classic view the dissociation probability is calculated when it a molecule is exposed with a Ti:sapphire laser with wavenumber of 800nm and the energy of . using gradient optimization method we find a tailored two rectangular laser pulse for controlling the dissociation of C-H bond of . Using classical method reduced the complicacy of solving schrodinger equation. In our optimization method in contrast with the usual controlling method experimental data is not needed and this reduced the controlling costs.

 

Human joints wear gradually by diseases like arthrosis and will fail. The Pain from joint erode, preventing tracking daily activities, wont disappear by medicines and joint replacement is a common treatment. Hip joint as one of the most important, largest and heaviest joints of the body,is no exception.
Over 600,000 worldwide annual hip replacement surgery is done. The joints are designed in such a way that it can move 15 years without significant wear. Different materials such as ceramics, polymers and metals are used in making it which before in vivo use, itmust succeed many tests like wear test.
Since making artificial joints become increasingly important in recent years and... 

Destruction of green lands, especially forests, is one of the most common forms of environmental degradation. Meanwhile, political institutions can play an important role in protecting or destroying the environment, especially forests. The creation of town and village councils as a change in political institutions and decentralization can have an impact on the environment. Land use change, implementation of development projects and the task of overseeing the implementation of environmental protection laws are among the duties and powers of councils that affect the coverage of various areas. At different eras, town and village councils’ elections have been annulled or dissolved in a... 

Robust model predictive control(RMPC) is a control strategy that has been widely adopted in industry and academic researches.In this project we have modified robust nonlinear model predictive control using SOS and dynamic feedback. In this control strategy we will linearize the nonlinear model of the system about it’s operating point. We will consider the error of linearization as an uncertainty and find an upper bound for uncertainty. Then we will change control objective to minimizing this upper bound. The most advantage of changing the control objective is that nonlinear system results a non-convex optimization problem but this strategy terminates a convex optimization problem. To find... 

In this study, the effects of treatment time and power of Low-frequency (LF) O2 plasma has been investigated for the surface treatment of polyethersulfone (PES) gas separation membranes. PES membranes prepared using dry/wet phase inversion using ternary mixtures containing 1-methyl-2-pyrrolidone (NMP) as solvent, water as non-solvent. The optimum polymer concentration was 32 wt.% , 61 wt.% and 7 wt.% for PES,1-methyl-2-pyrrolidone and water respectively. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. After treatment gas permeances of around 0.81 GPU for CO2, and 0.073 GPU for CH4 with selectivities of around 11.23 for CO2/CH4 were obtained.... 

Optical neural networks (ONNs) are custom optical circuits promising a breakthrough in low-power, parallelized, and high-speed hardware for the growing demands of artificial intelligence applications. All-optical implementation of ONNs has proven burdensome chiefly due to the lack of optical devices that can emulate the neurons' non-linear activation function, thus forcing hybrid optical-electronic implementations. Moreover, ONNs suffer from a large footprint in comparison to their electronic (CMOS-based) counterparts. Utilizing virtual optical neurons in the time or frequency domain can reduce the number of required physical neurons, but an all-optical activation function is still required,... 

One of problemsin an inverse problem like history matching is there is no unique solution. This means that maybe several diferent permeability maps can correctly reproduced the history of fieldt but there is no garanttee that these maps accurately predidct reservoir production behavior. One way to face and deal with this problem, except manipulation of solution and optimization algorithm (inverse modeling) is to use other data sources like seismic data, Variogram, pore volume, and fracture density or any other parameter obtained from geostatistical investigations.Multi-resolution wavelet analysis can be an appropriate tool to gather the necessary information to characterize the inverse model... 

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...