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,... 

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... 

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.

 

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... 

According to today’s medicine progress, the need for improving the medical facilities have been increased. Within the human body, the biomolecules concentration gradient is regulating the cell functions. Biological processes such as immune response, wound healing, and cancer metastasis have been affected by the bimolecular concentration gradient. So understanding the cell behavior in the presence of a chemical gradient can improve the understanding from these biological processes, and also would help in medical researches. On the other hand, finding the appropriate dose of the drugs and in some cases finding the most effective drug is a clinical challenge that made a new field of research in... 

In this thesis, we introduce a novel Artificial Intelligence (AI) system inspired by the philosophical and psychoanalytical concept of imagination as a ``Re-construction of Experiences". Our AI system is equipped with an imagination-inspired module that bridges the gap between textual inputs and other modalities, enriching the derived information based on previously learned experiences. A unique feature of our system is its ability to formulate independent perceptions of inputs. This leads to unique interpretations of a concept that may differ from human interpretations but are equally valid, a phenomenon we term as ``Interpretable Misunderstanding". We employ large-scale models,... 

The primary objective of this thesis is to provide solutions addressing some security loopholes in continuous variables quantum key distribution protocols. The coherent detection method is utilized in this particular quantum key distribution scheme, which is a phase-sensitive detection. To measure in the quantum noise limit in the detection part, we need a local optical oscillator, which must possess a high intensity and a consistent phase correlation with the quantum signal. Therefore, reconstructing the emitter’s reference phase in the receiver’s detection system is considered as one of the most critical challenges in these protocols. In order to attain this goal, in the early versions of... 

The development of clean, renewable and alternative sources of fossil fuels has increased in recent years due to various factors such as environmental pollution, reduced fossil fuel resources and increased energy consumption. The application of microbial fuel cells is one of the clean energy production methods using renewable sources such as municipal sewage. The microbial fuel cell converts the chemical energy stored in organic materials into electrical energy and simultaneously purifies the sewage. Increasing current density and power density are the most important challenges for microbial fuel cells. In this study, the two biocatalysts of Shewanella Oneidensis MR1 and Escherichia coli... 

In this study, the performance of different boundary conditions in dynamic analysis of embankment dams, with consideration of dam-foundation interaction, is compared. All of models are in 2D space. The behavior of dam and the foundation are assumed to be linear elastic. Dam is built of compacted clay, whereas three types of soil are considered for foundation: loose, Medium and dense sand. Direct method is used for dam-foundation interaction analysis. We used Finite Element Method (FEM) using 8-node, quadrilateral and isoparametric elements to analyse the models. The incitement is horizontal displacement with different frequencies that is applied to lower boundary of foundation. In addition,... 

Landslide is a natural hazard associated with economic losses and fatalities. The geometric of the slope, the soil properties, hydrological factors, and groundwater are important factors that affect the stability of a slope. The landslide investigation is important due to the identification and prevention of damages. Thus, more researchers studies on this subject. The new questions in this field are “how can simulate the vegetation effects in slope stability analysis?” and “what effects do precipitation and infiltration have on landslide triggering?”. Although the classic methods of slope stability analysis provide the initial information for the design, they have limitations in answering... 

This thesis presents a probabilistic framework for prioritizing the highway bridge network for seismic retrofitting and structural health monitoring. The basis of this framework is the risk analysis of the bridge network, which includes bridges and the links connecting them in the transportation network. Risk is defined as the probability of exceeding the sum of all losses incurred to the community in the event of a hazard. These losses include the direct economic cost of bridge repairs and damage to vehicles due to bridge failure, the socioeconomic cost of increased travel time for transportation network users, the indirect economic cost of excess fuel consumption and depreciation of...