Sharif Digital Repository

increased cohesion up to 4H pencil. Results of immersion test in water showed stability of coatings. Polarization test in naphtha and water mixture for stainless steel, copper and aluminum meshes demonstrated 98.89%, 86.25% and 66.6% protection efficiency respectively. In order to study of oil and water separation efficiency, mixtures of water and naphtha with different content of naphtha were used. Separation test for 200μm St.St mesh in different slopes demonstrated that changing of slop increase separation efficiency up to 95.5% for water and up to 100% for naphtha. Separation test for meshes with different pore size demonstrated that meshes with small pore size are more appropriate for... 

The railroad blocking problem emerges as an important issue at the tactical level of planning in freight rail transportation. This problem consists of determining the paths of each shipment which minimize the total cost subject to the key constraints such as limitation on travel time, limitation on number of dispatched trains, and limitation on the number of cars classified at each station. The multi-path railroad blocking model is developed and then a new heuristic algorithm based on the Lagrangian relaxation technique to solve the realistic rail network is introduced.To consider the uncertainty which is inherent in the demand and travel time (as a supply indicator of rail system), a... 

The purpose of this study is to find the conflicting assumptions of the main actors in the legislation process of Knowledge-based Act. Collecting and classifying all documents related to this policy process, and based on interviews with main actors involved in this process (with different objectives) and using thematic analysis, we first attempt to classify the main actors involved in the process. Second, we analyze the conflicting paradigms which have led to political conflicts in the process. This analysis helps to improve the policy process of similar acts in future  

Vortex-induced vibration is a known phenomenon in fluids flow that is being studied in different fields of engineering and usually, we want to reduce the harmful effects of this phenomenon on the subjected structures. Also, it is possible to use this phenomenon for harvesting clean energy from fluids flow. Energy harvesting from vortex-induced vibrations is based on the maximizing of flow instead of its reduction, and the utilization of these vibrations instead of their suppression. Vortex induced vibrations occur in any ranges of Reynolds numbers. Only in three transient regions cause a reduction in vortex-induced vibrations; therefore, even in streams with a velocity less than 0.2 m/s, it... 

In this study a droplet-based microfluidic system is desighned and fabricated to effectiverly lyse MCF7 cells and extract and purify their DNAs. The main purpose of this study is to transfer all the steps from macro scale to a microfluidic system containing a fluidic chip. This system is a semi automatic system and every part of the lysis and purification process is performed in one step. The first step is to encapsulate single cells and multi cells inside the droplets. By controlling the concentration of the cell solution, the number of encapsulated cells inside the droplet is efficiently and easily controlled and the cells were encapsulated as single cells and as multi cells inside the... 

One of the influential factors affecting the future price trends of a stock is the public sentiment surrounding that particular stock. In recent years, researchers have employed Natural Language Processing (NLP) techniques to analyze textual data present on social networks, aiming to investigate public opinions. However, there has been limited attention given to validating the users expressing opinions concerning the stock market. Much of the opinions shared on social networks lack a thorough examination and analysis of the market, often being solely based on the author's sentiments. This research endeavors to validate active users on the social network 'X' (Twitter) by developing a... 

The development of intrinsic theories for area-minimization problems was motivated in the 1950 by the diffichlty to prove, existence for the Plateau problem for surfaces in Euclidean spaces of dimension higher than two. After the pioneering work of R. Caccioppoli and E. De Giorgi on set with finite perimeter, W. H. Fleming and H. Federer developed the theory of currents, which leads to existence results for the Plateau problem for oriented surfaces of any dimension and codimension. The aim of this paper is to develop an existence of the Federer-Fleming theory to spaces without a differentiable structure, and virtually to any complete metric space. The starting point of our research has been... 

In this thesis, vve generali :ed the notion of (upper) gradient to arbitrary func- tions on a. metric measure space a.nd under some conditions -vve study deriva- t.ives of Lipschitz functions and their differential properties. Finally, we consider metric measure spaces that satisfy certa.in additiona.l conditions and give more detailed study of these notions  

Ground squeezing is defined as time-dependent shear displacement of rock mass that causes the decrease of the calculated excavation area of tunnels.Ground squeezing is one of the phenomenons that causes serious problems including the collapse of tunnels’ walls and TBM jamming during the construction of tunnels. Hence, the assessment of ground squeezing is an essential issue in tunneling. In this thesis, different ground squeezing potential prediction methods will be assessed. These methods consist of empirical, semi-emperical, analytical, and numerical methods. After assessing the ground squeezing potential, if it is evaluated high for a project, it will be required to consider the... 

Suppose $X$ is a locally compcat Hausdorf‌f space. We denote by $C_0(X)$ the Banach space of all continuous functions real or complex-valued def‌ined on $X$ which vanish at inf‌inity, equipped with the supremum norm. Suppose linear subspace $A$ of $C_0(X)$ is strongly separating, that is, for all pair of distinct points $x_1,x_2 \in X$, there exists $f \in A$ such that $|f(x_1)|\neq |f(x_2)|$. In this thesis, we show that Shilov boundary of $A$ exists and is closure Choquet boundary of $A$. Furthermore, \ we show that a linear isometry $T$ of $A$ onto such a subspace $B$ of $C_0(Y)$ induces a homeomorphism $h$ between two certain subspaces of the Shilov boundaries of $B$ and $A$, sending the...