Sharif Digital Repository

In Laws and Lawmakers: Science Metaphysics and the laws of nature, Mark Lang has presented an engagingly written, tightly argued, and novel philosophical account of the laws of nature. One of the intuitions behind the notion of a law of nature is, roughly, that of the many regularities we observe in the world there are some which appear to be due to mere happen-stance(“accidental” regularities, in the philosopher’s jargon)while others, which we call “laws,” seem to be possessed of a degree of necessity. although many philosophers, and certainly most scientists, will readily agree that there is a difference between logical, law-like, and accidental regularities, spelling out the nature of... 

Lots of micro hydropower potentials are spread all around Iran country. They have the capability to produce electricity for workhouses, residential areas, agricultural and animal husbandries and recreational tourism centers. Hence, Sharif University of Technology and Iran Water and Power Resources Development Corporation decided to design and produce three types of hydro micro turbines to cover all range of micro hydropower potentials available in Iran. These three types of micro turbines are Pelton, Banki and Axial and they are designed in order to cover high, middle and low heads in sequence. Frequency control of micro hydropower plants is so vital due to plant off-grid. The most prevalent... 

In order to control accesses in semantic environments, a semantic-based access control and policy specification language should be choosen. Upon to them, some security mechanisms should be designed and implemented. Several access control models and policy specification languages have been arisen, but seldom have focused on designing mechanisms to satisfy their models in any environment. In this thesis, we focus on implementation aspects of access control in semantic environments. We chose semantic web as our studying environment and an extension of the SBAC model named MA(DL)2 as our access control model. To control accesses in the selected environment, we divide semantic web into some... 

In recent decades one neo-Aristotelian school in metaphysics has appeared that with reconstruction on concept of "potency" or "power" try to explain metaphysical problems as: properties ,causation, laws of nature ,modalities and … .this school contradict all classical views in analytic metaphysics ,because they have commitment to Humean metaphysics that all metaphysical categories supervene on distinct particular facts in nature. Dispositional essentialism is one neo-Aristotelian theory saying that some natural properties have dispositional essence. In strong view of this theory, identity of properties supervenes on the structure of a network of properties and therefore properties are... 

The Concept of causation plays a major role in Hume’s philosophy and as yet has been debated between philosophers. This Thesis aims to Consider the main part of Hume’s view about Causation, but it also Ventutes into more recent approaches in this subject. In first chapter, we attend to Consider The project of Hume named "Seience of man" and The associative mechanism of causation is expressed. In Second chapter, We turn to three famous interpretations of Hume’s view and the meaning of two definitions of Causation is discussed. In third chapter, we try to analyse the real nature of necessary Connection. According to fourth chapter, we again attend to three interpretations and recognize the... 

In this study, using a non-interference experimental method, the chemical luminosity of CH* in co-flow diffusion flames with soot and using natural gas hydrocarbon in a laminar flow regime has been investigated. In addition to experimental research, in current research, numerical simulation has been used to extract information such as temperature field, mass fraction of species, and flow structure and comparison and validation with experimental results. Numerical simulation has been used to simulate the mechanism of CH* species formation. Two different mechanisms have been used. In addition, the Soot simulation model from the Moss-Brookes model and radiation heat transfer mechanism... 

Modern physics and the standard metaphysical point of view, together, result a contradiction which we will explore its roots in this thesis. Be- sides, focusing on various identifications of individuality and the prin- ciple of identity of indiscernibles will made us to choose between to metaphysical and equal pockets, Particles as individuals and particles as non-individuals.Physics alone could not help to choose between these too pockets. Therefore, we will face a metaphysical under-etermination which we have to break in order to save our realistic ontological com-mitments. By a breif study among the possible ways for breaking that underdetermination, structural realism will be the most... 

Intelligent design theory is based on this idea that Darwinian theory of evolution can not explain Irreducibly complexities in organisms. Intelligent design theory in explaining these complexities conclude the existence of an intelligent designer. It is claimed that by remaining officially agnostic about the nature of the designer, intelligent design theory can be offered as a scientific claim, rather than a religious one, which could make it a viable alternative to Darwinism. In this thesis we study sober's point of view on intelligent design. Sober believes that, initially, we shoud present the strongest formulation of intelligent design theory and then evaluating whether this theory is a... 

The environmental impacts of chemical processes significantly affect the design of these processes and emphasize issues such as changing the reaction path, separation methods, thermal integration, and finally multi-objective optimization. Therefore, it is necessary to investigate the influence of environmental indicators in the design of chemical processes. The background system in this assessment includes two process units, olefin and polyolefin. Environmental impacts assessment has been carried out using the ReCiPe endpoint method (an efficient method for life cycle impact assessment that will be described in chapter 2) and these impacts have been determined in the form of damage to human... 

recent years, by the huge increase in the number of components on a board, the bus routing problem and minimizing the number of layers of a board has emerged as a significant challenge in designing Printed Circuit Boards (PCBs). Two related theoretical problems to bus routing are the Rectangle Escape Problem (REP) and the maximum independent set of rectangles problem where both of these problems are NP-hard in the general form. In this thesis we study some variants of these problems and try to improve the running time or approximation factor of the best algorithms previously provided for solving them. The maximum disjoint set of boundary rectangles problem is a variant of the maximum... 

With the daily increasing demand for energy, we are facing many crises, such as environmental pollution and global warming, etc. Geopolitical issues can also lead to problems for some countries in reaching the energy demand considered in their development plan of them. For this purpose, a part of the global research is focused on removing these obstacles. One of the methods that can be used to produce cleaner fuel, or more precisely "biofuel", is the gaseous fermentation of synthesis gas by microorganisms and algae. A rod-shaped, anaerobic microorganism called Clostridium ljungdahlii uses synthesis gas for its reproduction. In other words, this bacterium can ferment carbon monoxide, carbon... 

In the present study, the Ricci curvature is defined on the graphs by using two methods and the lower bounds are obtained. In the first method, which is related to Bakry and Emery, a definition for Ricci curvature and lower bounds would be obtained by using Curvature-Dimension inequalities.The second method which is related to Ollivier, is based on the fact that in Riemannian Geometry,the Ricci Curvature controls the velocity of convergence and divergence of emanated geodesics from a same source. Next, the more Curvature-Dimension inequalities for Ricci curvature would be obtained by using local clustering. Finally, the Bonnet-Myers theorem would be proved on the graphs.
 

In this thesis, a discrete exterior calculus is studied. Discrete exterior calculus is an attempt to create a discrete analogy of differential geometry and topology which is potentially applicable in computer science and physics. At first, simplicial complexes are presented as approximation of smooth manifolds. Then discrete forms and discrete exterior derivative are defined. We will observe that Stokes, theorem can be stated and proved in discrete analogy too. We will obtain Hodge operator by using dual complex and after that discrete Laplacian and Heat kernel will be calculated by using Hodge operator. In addition, we will define discrete vector field independent of discrete forms and then...