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The aim of this thesis is to study invariants of Diophantine forms and equations. These invariants are the transformations that do not change the original equations and forms. This thesis has a different view to the concept of invariants from Hlibertian view. Based on this new definition, by having one of the solutions of the equation, new solutions can be found with invariant method. The number of these solutions can be finite or infinite. In case of infinite solutions this method is more important. The focus of this thesis is on forms and linear invariants. The most important result in this text is about two main theorems that can classify the invariants of all completely decomposable... 

The main topic of this dissertation is to find methods for obtaining parametric solutions and linear/nonlinear invariants of Diophantine equations and consists of 4 chapters. The first chapter consists of some introductory discussions. The second chapter begins with a review of linear invariant, U-invariants, covariants and the concept of semi-invariants. The generators of maximum degree 3 for producing all linear invariants are introduced in Chapter 2 as well. Moreover, the relations between 3rd and 4th degree Hilbert invariants in terms of Procesi bases are included in this chapter.In chapter 3, a general conjecture is given to check whether there are finitely many solutions to a... 

Nowadays, chemotherapy is one of the common ways to treat cancer. Although, chemotherapy is used to kill cancer cells , chemotherapy drugs also target healthy cells and tissues of the body. In practice, it is difficult to strike a balance between injectable doses of drugs and toxicity in the body, and physicians are always looking for an effective treatment plan. One of the most common drugs that physicians use in chemotherapy is cell-cycle-specific drugs. These types of chemotherapy drugs affect only a certain phase of cell cycle and to a certain extent. Since the lifetime of the cancer cells is uncertain, the effective use of these drugs depends on the correct injection time of the drugs... 

In this thesis we are going to improve an ultrasonic flowmeter accuracy by considering the influence of different parameters like temperature, pressure, etc. Firstl of all different cases of flow condition in which ultrasonic flowmeter may work are specified, then velocity and temperature profile of pipe flow are determined using Fluent software. In thr next step ultrasonic pulses transmitted are simulated by the use of code written in Matlab to find wave travel time in the flow. Evetually an accurate relation of calibration for flowmeter is determined by the use of travel time and all other flow properties to evaluate the accuracy of flowmeter in diffent cases. Relation extracted can be... 

Ethylene is considered as one of the key materials in the petrochemical industry and has a particular importance. Polymerized ethylene produces polyethylene, which is widely used in plastics and pipe-manufacturing industries. Ethylene is mainly produced by the processes of catalytic cracking or thermal cracking of heavier hydrocarbon compounds. In these processes, acetylene is produced as a by-product, which deactivates the Ziegler-Nata catalysts in the polymerization unit of ethylene. Therefore, there should be some considerations to reduce acetylene to its minimum value -around zero. For this purpose, the fixed bed catalytic reactor is used to hydrogenate acetylene to ethylene. Various... 

In this thesis, the value-ladenness or value-neutrality of technology, new social media and as a result Instagram is investigated. It is also discussed whether values can be taken into account during the design process of technical artefacts, including new social media and Instagram, and methods are developed for this purpose. Several methods have been developed for this purpose, some of them and their compatibility with modern social media are explained; including the Value-Sensitive-Design method and the disclosive computer ethics design method. The frameworks of ethical philosophy such as virtue ethics are reviewed and the appropriate ethical framework for the analysis of new social media... 

Obtaining polymers with desired properties is very important from industrial point of view. Weight average molecular weight and polydispersity are two important polymer properties. It is also important to obtain a high monomer conversion. In this thesis production of polyvinyl acetate is considered. Under special conditions, the vinyl acetate reactor dynamics become oscillatory which makes the reactor control difficult. For obtaining polymer with desired properties, an objective function which includes weight average molecular weight, polydispersity and monomer conversion has been defined. Then by minimizing this objective function the optimal temperature trajectory is obtained. In this... 

In recent years there is a growing trend in designing efficient health care systems. The applications of operations research have been instrumental in advancing this growing trend too. The blood management issue has raised concerns for human on the other hand. Blood is one of the vital commodities in the field of health. Despite significant advances in the field of medicine, a suitable replacement for this vital commodity has not been found yet. Collecting and managing the distribution of blood that is discussed in the blood supply chain management, requires careful planning and managing. In this research blood inventory management in hospitals considering the uncertainty of supply, demand... 

Generally, the costs of logistics and distribution are included in the significant share of the product price. Hence, choosing appropriate decisions and reducing these costs can have an important effect in reducing the price of products and services, increasing the competitiveness of enterprises. One of the most important measures, in order to achieve this goal, is to integrate location of distribution centers and the routing paths of goods. That how these decisions are made in the networks and discrete problems seriously has been taken into consideration but in continuous areas due to the complexity has not been studied a lot by scholars. In this study, we try to develop a model for...