Sharif Digital Repository

Present work focuses on the influence of Heteroatom(s) on the bacisity of specific group of amines through the intramolecular hydrogen bonding. This group includes Aza-Crown Ethers specifically. We used Spartan and Gaussian packages to gain optimized structures for all compounds in order to explore the influence of the intramolecular hydrogen bonding on the bacisity of amines. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6-311++G(d,p) level of theory. The Hf/6-31+G(d,p) level was used for all single point calculations in the solution phase. As commonly used solvents in organic and biological reactions, the solution phase calculations were carried... 

Using thick plates is common in different industries including ship and pressure vessel manufacturing.In this research a plate forming method called line heating is examined. This method requires basic equipment and is very economical.Heat transfer between gas torch and plate is studied in more detail. Impingement jet model is used to simulate the effect of torch on plate. Velocity and temperature fields of exiting air are calculated in Fluent, a commercial software. Then heat is transferred between hot air and plate, which is related to velocity field and both temperature distribution of air and plate. In this method torch moves along the plate. In order to simulate this movement, a moving... 

This thesis addresses the problem of configuration selection for an urban air mobility EVTOL aircraft utilizing a robust controller approach.First of all, to arrive at a final configuration, different feasible concepts for an urban transportation EVTOL aircraft have been proposed and studied during several brainstorming sessions. As a result, five potentially viable configurations have been selected for further investigation and analysis. These preliminary designs have been nominated utilizing the method of decision matrices and considering the design team and control system designer’s selection criteria. Finally, a tilt-rotor tandem-wing configuration has been selected to go through the... 

In this study, using the B3LYP/6-3111++g(d,p) computational level, we have explored the possibility of formation of some organic and bioorganic cation-cation clusters (CCC) in the absence of any anionic stabilizing species. Furthermore, we have shown the existence of a barrier energy for exothermic dissociation of these clusters. Herein, we have selected some biomolecules such as the chloroquine (CQ) antimalarial drug . The selected molecules possess the basic sites and can function as both hydrogen bond donors and acceptors. Also, a facile and direct synthetic route toward the rhodanine derivatives and thiazolidine-2,4-diones via a three-component coupling of carbon disulfide, primary... 

This thesis is divided into two parts: In part I, which is theoretical part, we were looking for a computational method which is extensively comparable with experimental results to determine pKa of wide variety of organic compounds. The pKa is an important property in many sciences such as chemistry, biology, and material science, since inclination of a compound to donate or accept a proton is fundamental to understanding many chemical and biochemical processes. Experimentally determined pKa values are not always available from literature sources and often estimated values are employed in their place. It is useful, therefore, to have reliable and accurate means of calculating relative and/or... 

Hydrogen bonding is an important weak interaction encountered in gas, liquid, as well as solid phase. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology. Amides have several applications as drugs, antibacterials and antifungals. Different substituents can affect the acidity of amides. Investigation have shown that hydroxyl function group can increase the acidity of many organic molecules through interamolecular hydrogen bonding. The goal of this project is to investigate the acidity of cyclic amides and barbiturates by adding hydroxyl group in the gas and solution phase. All the gas phase optimizations and... 

Hydrogen bonding is an important weak interaction encountered in gas and liquid, as well as solid phase. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology. Beta diketones have several applications in organic, inorganic and analytical chemistry. Different substituents can affect the acidity of beta diketones. Investigation have shown that hydroxyl function group can increase the acidity of many organic molecules through interamolecular hydrogen bonding. The goal of this project is to investigate the acidity of hydroxyl containing beta diketones in the gas and solution phase. All the gas phase optimizations... 

One of the goals of the current research is to investigate natural structures to inhibit Ras proteins that belong to the family of guanosine triphosphatase proteins. For example, one of the common mutations is Kras mutations, which are seen exclusively in pancreatic ductal adenocarcinoma. Changes in Kras protein expression are observed in 30 percent of lung cancer cases. Kras mutations occur in 35-45 percent of colon cancers, leading to drug resistance. Our work method in this research is that we collect a dataset of natural compounds for the target protein. Then, the binding energies of these structures with the receptor protein are calculated through Autodoc Vina. After that, using deep... 

Hydrogen bonding is an important weak interaction encountered in gas, liquid, as well as solid phases. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology.
Polyols or polyhydric alcohols are, strictly speaking, simply organic chemicals containing more than two hydroxyl groups. Each hydroxyl is attached to separate carbon atoms of an aliphatic skeleton.They may also contain ester, ether, amide, acrylic, metal, metalloid and other functionalities; along with hydroxyl groups. Polyols are obtained from many plant and animal sources and are synthesized by a variety of methods. Among important properties of... 

A series of V2O5 catalysts supported on multiwall carbon nanotube (MWCNT), single wall carbon nanotube (SWCNT) and graphene were synthesized by hydrothermal and reflux methods for oxidative dehydrogenation of propane (ODHP) to propylene. The catalysts were characterized by techniques including the BET surface area measurements, XRD, FTIR, H2-TPR, NH3-TPD, FESEM and UV-vis diffuse reflectance. The performance of the catalysts and the supports were subsequently examined in a fixed bed reactor. The vanadium catalyst supported on graphene with C/V molar ratio of 1:1 synthesized through the hydrothermal method had the best performance under the reactor test conditions of 450°C, feed C3H8/Air... 

Over the last few years, much effort has been directed into developing new materials that have specific antibacterial and antifungal activities that can be used to fight infections and to create sterile conditions. Nanotechnology could become very important in this research field, providing the tools needed to synthesize copper-containing nanomaterials showing an enhanced bioactivity. This nanomaterials have been used in a number of textiles, plastics and ceramics coming on the market in recent years. In this thesis, we synthesized copper-polymer nanocomposites by blending of pre-formed copper nanoparticle into pre-synthesized polymer. We used a new method of nanoparticle preparation by... 

This thesis is divided into three parts: In part I, structure and electronic properties of ionic liquids based on N7, N9-dimethylguaninium cation and α-amino acid (Gly, His, Phe, Try, and Tyr) anions and also ionic liquids based on 1-ethyl-3-methylimidazolium [emim]+ cation and alkyl-trifluoroborate ([RBF3]-, R=n-CmH2m+1 (m=1-5)) anions were discussed at the DFT(B3LYP)/6-311++G(d,p) level of theory. Then, the effect of chain length in anion on the nature and strength of interaction between cation and anion was investigated. Our results indicated that interaction energy values decrease with the increase in side chain size in anion. NBO and QTAIM results indicated that the interaction in these... 

Acidity values of some compound (e.g., alkanes, alcohols, carboxylic acids and amines) with or without boron substitute have been studied theoretically to evaluate the influence of boron on acidity of organic functional groups. We have derived the unoccupied reactive orbital that show the maximum localization on the boron pπ atomic orbital overlapping with the lone-pair orbital of an electron donor. Localization of unoccupied reactive orbital on the boron pπ atomic and the polarizability of the boron center are two factors which affect acidity values of functional groups. Conformational searching was performed using MM (Molecular Mechanics). The most important conformations were optimized at... 

It is believed that intramolecular hydrogen bonding and also conjugation can affect the acidity power of organic molecules. But simultaneous effects of intramolecular hydrogen bonding and conjugation have not investigated systematically yet. In this project, we choose Ascorbic acid as a basic structure. Then we have changed its structure conveniently, and have explored the roles of hydrogen bonding and conjugation on the acidity of this molecule by using B3LYP functional with the 6-311++G(d,p) basis set. After that we similarly investigate these effects on the acidity of three different systems, including enols, enamines and alcohols. In this project we probe the effect of different hydrogen... 

Brown and Henneaux showed that asymptotic symmetries of asymptotically form a conformal group in two dimensions [1]. Also they could derive classical central charge of theory. Fourteen years later, Maldacena, conjectured that this Holographic correspondence could be true for a specific theory a simplified chromodynamics in the boundary of ), this holographic theory attracted physicist communitee's attention. Many physicists tried to make this conjecture more precise. It is worth to say that, no example of holographic correspondence has been completely proven, till now, Because of the difficulty of the calculation. However these days we consider Madacena conjectrure in any arbitrary... 

This thesis contributes two separate predictive direct torque control methods; based on hysteresis and fuzzy logic for Brushless Doubly Fed Induction Machine (BDFM). Initially Chapter 1, focuses on BDFM history and concept of this machine and after that a short review about the development of BDFM and the Field Oriented Control will be studied. Chapter 2 introduces the d-q-0 state transformation matrix, dynamic equation of BDFM and represents its steady-state equivalent. Furthermore, in this chapter the bond graph model of BDFM is studied and via distinguishing all energy ports the bond graph model of this motor is introduced and validated, finally the result of this model is compared with... 

This study discusses about mass customization and optimization of supply network in which both goal considering to set the flow of raw material and final product to satisfy the customer demand. The mass customization is more important concept in this study, so that this goal is placed to the first objective. In this research, the model which contained both goal is presented. The model focus on mass customization and try to satisfy various products demand, which constitute 3 kind of speed demands. Each product can satisfy in 3 way: fast, normal, slow.In the first model the new approach present in which the speed affects all of supplying, manufacturing and distributing system. The system try... 

Knowledge Based Firms are considered to be important for the economic development of a country in regards to both employment growth and innovative activity. The latter is believed to contribute significantly to the increase in productivity and therefore the competitiveness of Iran’s economy. This study contributes to the above literature by investigating the factors that are believed to treat the growth of such firms in Iran. The purpose of this study is to identify functional risks of vital signs monitors via Fault Tree Analysis (FTA) method to use as a guide for manufacturers to identify and control hazards. Therefore, 30 knowledge based firms were selected as sample. Then, based on a...