Sharif Digital Repository

The importance of the issue of laws of nature is obvious so that some say the purpose of science is discovering the laws of nature. In his “laws and symmetry” (1989) van Fraassen takes an antirealistic position toward the laws. His project is to clear science from metaphysics, and since the notion of laws of nature has heavy metaphysical presuppositions it should be eliminated from the literature of science. He tries to provide three kinds of arguments against the notion of laws: first, historical arguments, second, arguing in favor of insufficiency of all presented accounts of laws, and third, rejecting the tasks that accounts of laws should do. In van Frassen’s view, studies of science... 

Past theory-changes in science were sometimes accompanied by radical conceptual shifts. This has urged some philosophers of science to project the same possibility onto current theories and suspend belief in the conceptual parts of our current best scientific theories. This type of argument is called the “pessimistic induction” (PI) and is often used by scientific anti-realists. Scientific realists, on the other hand, have argued against PI, by insisting that past theory-changes were not as radical as anti-realists suggest, as well as by appealing to the differences between current and past science. In recent decades, anti-realists, such as Kyle Stanford and Brad Wray, have renewed the... 

The No-Miracle Argument (NMA), the primary argument employed by realists to support their position, has been understood in two different ways: as a kind of IBE and as a probabilistic argument. Following an overview of this argument and its status, this dissertation addresses and evaluates the most recent version of NMA given as a kind of IBE, as well as the many versions of its probabilistic forms. I then move on to the criticisms of the NMA's probabilistic forms. Among these criticisms, I have devoted three chapters on the base rate fallacy, which has received little attention to date. In the first of these three chapters, I discuss the base rate fallacy criticism and the responses of... 

Various philosophical views on scientific models, in this research, are reviewed and criticized. From a syntactic point of view, a scientific theory is nothing but its models, and this is the theory that illustrates how the model is constructed. Pragmatic view, by adopting a pluralistic view, argue that the interpretive model provides the basis for the concretization of the abstract concepts of the theory, and it is possible that representational model is incompatible with the theory itself. The model works better than theory even in functions such as prediction, explanation and representation in some places. A group of philosophers believe that with the introduction of fiction discussion,... 

Technology, especially in recent centuries, has changed human form of life. Case studies show that there is a mutual relationship between human being and technology; Human is a technological being and technology is also a social entity. Therefore, trying to develop a conceptual framework to describe the important role of technical artifacts in our life can be regarded as a legitimate philosophical concern. Peter Paul Verbeek is one of the contemporary philosophers who take this concern seriously. He, by using the doctrines of The Empirical Turn in the philosophy of technology, has developed a lexical system, called post-phenomenology, to describe the role of Technology in human’s perception... 

Scientific Essentialism is a relatively new theory which aims to give fruitful answers to some of the major problems of philosophy of science by using a rich background of essentialist metaphysics and discoveries of the Modern Science. This thesis particularly explores Scientific Essentialism’s answer to the interwoven problems of Laws of Nature and Counterfactual Conditionals. First of all, it seems that Scientific Essentialism is able to solve the problem of Laws of Nature without encountering the difficulties which other theories had. Also, being rich in metaphysics enables Scientific Essentialism to provide a considerable solution to the problem of Counterfactual Conditionals. Finally,... 

Different views and approaches have been adopted regarding the nature of scientific theories in the philosophy of science, which can be generally divided into two main parts: A) Syntactic (linguistic) approach, which is also called the traditional or received view, B) Semantic approach (model-based view).The main and dominant idea in the syntactic view, first proposed by logical empricists is that a scientific theory is an axiomatic system in a formal language (first-order language) that is subject to deduction and is partially interpreted by a set of correspondence rules. This view has been the subject of numerous attacks and criticisms since the 1960s, after which an alternative approach,... 

All the main knowledge currents —from the humanities to the experimental sciences— consider themselves explicitly or implicitly indebted to Neo-Kantianism, an approach that, by removing the sensory-material component from the production of reality, prevented the entry of all accidental and unexpected elements into the various fields of human knowledge and gave a not very productive peace to the European world: the peace that came to Europe not only in experimental sciences but also in politics and economy, but it made the existence of Europe weak and sterile. This is the judgment that I have tried to make as far as I can to show what fate the acceptance of Neo-Kantianism brings to man. The... 

Earlier in the philosophical tradition, the realists’ view that world exist in itself, independently of our knowledge, had been challenged by idealists, who denied such existence and considered the world and its objects as a function of (our) perception. Today, some philosophers have challenged the (scientific) realists’ belief in the existence of scientific unobservable entities, such as electrons, quarks, forces, gravitational fields, cells, bacteria, genes and so on, that are posited by the modern scientific theories. The debates which have been made in this regard, in recent decades, have spurred an important controversy known as “scientific realism and antirealism debate” in the field... 

Nowadays, microgyroscopes are among the most important products of MEMS. The production of small, precise and inexpensive gyroscopes has become possible as the result of recent developments in fabrication technology. In this thesis it is intended to introduce a new method for manufacturing more precise microgyroscopes regarding manufacture facilities. Using this new method, sensitivity and resistance of microgyroscopes are increased against noises which are primarily caused by vibration and rotation about undesirable axes. The rotational movement imposed on the gyro is detected through fluid flow within its torus channel. This transformation facilitates the measurement of the initial motion.... 

The fiber-reinforced composite materials possess advantage for structural purpose in various industries. Delamination is recognized as one of the major causes of damage during drilling of fiber reinforced composites, which not only reduces the structural integrity, but also has the potential for long-term performance deterioration. It is difficult to produce precise quality holes with high efficiency by conventional drilling method. Drilling is frequently applied in production cycle while the anisotropy and nonhomogeneity of composite materials affect the chip deformation and machining behavior during drilling. In this thesis, a new non-traditional drilling technology is presented for solve... 

Superalloys are widely used in aerospace and power industries due to the good performance at high temperatures for examples gas turbines, steam turbines and aircraft components. In addition to the turbines cobalt-base superalloys are used in medical implants such as knee and hip joints. The main strengths of the superalloys are heat-resistant, retaining their high mechanical and chemical properties at high temperatures, high melting temperatures, high corrosion resistance, resistance to thermal fatigue, thermal shock, creep, and erosion. Because of difficult to machine properties of superalloys, grinding is one of the effective methods for machining superalloys. The surface integrity of the... 

U-shaped assembly lines usually are more effective than straight lines. Therefore special attention has been paid to u-shaped line balancing problem in recent years. On the other hand most articles on the line balancing problems are investigated for the first time. However, within the lifetime of an ALB, the balancing problems do not occur only once prior to its construction, but rather continuously as rebalancing. For example whenever the demand structure or production technology changes or producing seasonal products, the ALB needs to be reconfigured. So many balancing issues in the real world are related to re-balancing of production lines.
Therefore in this study, U-shaped assembly... 

Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to reduce machining forces is application of ultrasonic vibrations. In this study ultrasonic assisted drilling is applied to reduce thrust force in drilling of GFRP laminates. In order to conduct experiments a setup is designed and fabricated to apply both vibrations and rotation to drill bits. Using Taguchi method, a set of experiments is conducted with feed rate, spindle speed, point angle and ultrasonic vibration amplitude as control factors. The results show that applying... 

Lameness in dairy cattle is a crucial welfare issue after infertility and mastitis in dairy industry, and over the years scientists are attempting to present a detection method. In recent it is attracting more attention to make the identification and discrimination of sounds and lames systematic and automatic. Right now, the most hopeful results have been obtained through the measurement of Ground Reaction Forces (GRF) of hooves, and analysis of load distribution between four legs, which seems applicable for wide use in dairy industry.However, the accuracy, validity, and reliability of discrimination is still far from an acceptable point, that is because of a great lack in understanding... 

Drilling super alloys with a good hole quality and acceptable surface finish is a constant challenge in modern industries dealing with such materials. Ultrasonic assisted drilling is a modern and nonconventional method of drilling which has attracted many researchers attention recently. In this study deep drilling on Inconel 738 LC is done using ultrasonic assisted drilling technique and the results are compared with those of Electro Discharge Machininng or EDM method. The results show that Ultrasonic Assisted Drilling or UAD is an appropriate alternative for EDM of Inconel. The whole process time is decrease dimensional accuracy is improved and surface roughness is decreased significantly.... 

Hydrocephalus is a desease which causes by unnatural accumulation of cerebrospinal fluid in the brain ventricles. One of the most convenient ways to treat hydrocephalus disease is to use a brain shunt which consists of ventricular catheter, valve and distal catheter. Ventricular catheter obstruction is the main reason for shunt replacement in the human brain. This project attempts to remove obstruction of the ventricular catheter by mechanical forces. For this purpose, a magnet and a variable magnetic field suggested to apply mechanical force on a brush sliding on the shunt. On the inner surface of the ring-shaped magnet, brushes have been embedded and the magnet is placed on the outer... 

Ultrasonically assisted machining process has been introduced as an effective solution to improve machining quality of mechanical parts. This study aims to reduce the drilling induced delamination to increase mechanical properties of CFRP laminates. Delamination decreases the strength of laminates under static and dynamic loads. Drilling parameters (feed and spindle speed) and ultrasonic vibrations amplitude are chosen as design experiment factors. Taguchi design of experiments method is used to study the effect of input factors on drilling thrust force, delamination factor and residual strength of drilled laminates. Input factors are in three levels and Taguchi L9 array is utilized. To... 

Ultrasonic assisted grinding is a novel method for improving the grinding process of difficult-to-cut materials. In the present research a novel set-up has been designed and manufactured for utilizing ultrasonic vibrations in cylindrical grinding. The designed ultrasonic head vibrates a rotating workpiece in axial direction. An alumina-zirconia ceramic (AZ90) has been selected as the workpiece material. Energy aspects and workpiece surface characteristics of ultrasonic assisted cylindrical grinding (UACG) and conventional cylindrical grinding (CG) processes have been analytically modeled and corresponding grinding experiments have been performed. The combined kinematics of the cylindrical... 

The issues relevant to lubricants in industry, construction and production processes such as machining and grinding have been recently taken into serious consideration. Unlike the positive effects of applying lubricants on machining forces, chip formation, thermal defects which lead to force reduction, lower power consumption and surface quality improvement, its conventional usage has adverse effects such as environmental problems, high cost of high volume lubricant application as well as recycling problems. Therefore, attention was drawn toward chip removal under dry or near dry conditions and as thermal defects such as surface burning is important particularly in grinding, grinding under...