Sharif Digital Repository

The system considered on this structure is for the design on mid-high Buildings from 15 and 20 floors above the base level and n floors below the base level and the limitation of the number of floors is due to the computer facility and restrictions. There is going to be an irregularity in some chosen floor at lower-floor, mid-floor, or upper-floor which is assuming one floor from the structure to have a different height with respect to the others. The height of the considered floor is going to increase up to 25% with respect to the other floors and the design of outriggers with these three assumptions is going to be assessed separately. In this system, a central core of steel is constructed... 

In this work the effect of recycling process and nanometric CaCO3 on the rheological and heat-sealing properties of co-polymer Polypropylene (R40) was studied. Nanocomposites with recycled and neat matrix were prepared with twin extruder. Complex viscosity, dynamic modulus, flexural and tensile properties, impact strength and sealing ability of nanocomposites of neat Co-PP (R40) and Recycled Co-PP (RPP) determined according to the relevant standard specifications.Rheological analysis revealed that incorporation of nanofiller enhances values of Complex viscosity and dynamic modulus, broadening molecular weight distribution (MWD) and decrease cross over point (ωc, GC) for RPP. In this study,... 

Conformal Field Theory provides an efficient method for studying physical problems in critical point. Correlation length becomes converge in this point. It can also be clarified that some curves are observed in geometrical phase transition which are conformal invariant and they can be studied using SLE(k). The first mathematical generalization of SLE(k) while keeping the self-similarity property, leads to SLE(k,p). Conformal field theory and SLE are interrelated and their parameters are interpretable for each other. One usually studies the problem in the upper-half plane. Here we consider the problem using a map like (w=L/π Ln z) between the upper-half plane and a special region (e.g. a... 

Achieving low group velocity of light can result progress in many fields. In this project by using complex time domain frequency, achieving method to zero group velocity is proposed. The proposed structures in this thesis consist of two lossless and lossy structures which by considering the modes with complex time frequency are excitable. Using leaky modes to analyze these structures, made them suitable as they can be excited from free space. Using slow light can lead to optimized devices because of the more interaction of light and matter which besides smaller devices too. Additionally slow light is being considered in designing optical memories, quantum computers, optical processors and... 

A power plant cooling tower is like a tower, which needs to be studied very carefully from the aerodynamics point of view. Both the aerodynamics forces on the plume and intake stram are affected by the local winds and the performance of cooling tower decreases. There is a symmetric turbulent flow through the cooling tower if there is no. Wind blowing creates different vorticies, which appear in the lower section of the tower. Their periodic and wuick movments causes deficiency in towers performance and efficiency. Additionally there is wind effect on the plane of cooling tower and this causes a chocked plume which is named Wind Cover. The objective of this study is to decrease the adverse... 

In this research, we studied the effect of compatibilizer and short glass fiber on microstructure and mechanical properties of PBT/PC blends. Fisrt, Antioxidants and sodium pyrophosphate dibasic were used to suppress transesterification in PBT/PC Blend. The results showed that best composition occur when both of them are used. In the next step, we used 3%wt MBS (methyl methacrylate-butadiene-styrene) and saw that this weight percent of this compatibilizer doesn’t useful. Moreover addition of short glass fiber to PBT/PC was examined and the results showed that mechanical properties of composite are extensively increased. Also in this step, we proved this idea that we can replace some of PBT... 

The importance of housing, as one of the most important consumable and investable household goods, is not hidden from anyone. The cost of housing (which can include the cost of renting a property, the cost of repaying a purchase loan, or the opportunity cost of its purchase capital) is a large part of the consumption basket expenses of households. Housing is considered the biggest asset of many Iranian households. As a result, access to an accurate prediction with the least error becomes doubly important for Iranian families. In addition to households, knowing the factors affecting the equilibrium price and estimation of housing valuation for governments (a useful tool for fair taxation) and... 

Self-Assembly (SA) plays a critical role in the formation of different phenomena in nature. This phenomenon can be defined as an arrangement of meaningful patterns with the aggregate behavior of simpler structures. One of the examples of Self-Assembly can be considered of the formation of ice crystals from ice molecules. Previous works mainly focus on graph grammar and self-assembly in fully observable environments. These algorithms mainly consist of two main stages: first, constructing simpler structures and then joining these simpler structures to form a complex structure. The challenges of the previous work can be considered as the necessity of a central controller in the formation of... 

This research investigates the impact of mass labor migration on the incentives for adopting artificial intelligence (AI) technologies in industries. The study adopts a theoretical framework based on the model introduced by Acemoglu and Restrepo in their seminal 2016 paper. In the modeling framework of this research, there is a representative firm and a technology monopolist. The representative firm operates under a task-based production function, which allows the substitution of workers’ tasks with machines powered by AI, up to the technological capacity available. The technology monopolist determines the technological capacity of the firm, provided that it has sufficient incentive to... 

In this research, Cu-TATAB/Polyurethane (PU) nanocomposite fibers were prepared via electrospinning method in order to increase the overall extraction efficiency. The incorporation of Cu-TATAB, as a metal organic framework (MOF), in the synthesized nanocomposite contributed to the enhanced efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of organochlorine species and their determination was subsequently performed by gas chromatography-mass spectrometry (GC-MS). To achieve the maximum efficiency of the synthesized sorbent, the parameters of MOF percentage in nanocomposites, solvent type and volume, desorption time, solution ionic strength and... 

Engineering polymers are being increasingly used in a wide number of applications related to tribological properties. Many chemical and physical methods have been utilized to modify polymer surfaces by depositing thin inorganic films. Most of these techniques are based upon the use of high energy sources that ultimately can damage polymer surfaces either chemically or physically. Incorporation of fillers as reinforcing materials significantly changes various properties of thermoplastics. Friction stir processing (FSP) is a tool to modify the surface properties of materials. It has been developed for upper surface modification of metals in recent studies, exclusively by making surface... 

In this study, role of molecular weight and Molecular Weight Distribution (MWD) on joint strength of polypropylene was investigated by hot plate welding. Standard tensile specimens of three different co-polypropylene with low, medium and high Melt Flow Index (MFI) values (MR230C, 440L and 548R respectively) were injected and welded after cutting. Hot plate welding device was used to join specimens. Melt Flow Index and dynamic rheology tests were employed in order to study the rheological behavior of polymers melt. Furthermore tensile test was done to investigate joint strength of specimens at 150, 175 and 200 ͦ C. It was observed that in constant temperature, increasing viscosity (typically... 

By the advance of wireless communication systems, requirements to more advanced systems is increased. Circularly polarized antennas are considered as a robust solution to the demands of contemporary systems because of their unique attributes. This polarization is being used in various systems like satellite communication, global navigation system, mobile communications, wireless sensors, radio frequency identification, wireless power transmission and etc. Different designs are proposed to achieve circular polarization which among them the ones using single feeding techniques are more favored because of their ease of fabrication and excitation. In this thesis, three circularly polarized... 

The primary goal of seismic design requirements of building codes is to protect life safety of occupants during severe earthquakes. Thus it is required that collapse probability of designed buildings to be acceptably low. However current design codes are strength based and intrinsically experimental. Thus collapse safety of buildings designed by these codes is not known quantitatively. The history of formation and update of seismic building codes is marked by big earthquakes; often serving as landmarks for the evolution of seismic codes and detecting its deficiencies. As time passes, the design criteria become more and more articulate and ambitious, just as the design objectives evolve from... 

One of the most efficient methods in stiffening tall buildings to withstand lateral loads such as wind loading is to link the shear resisting core to the exterior columns using outrigger trusses. Many tall buildings such as Taipei 101 have benefited from outriggers. In this system, the outriggers force the perimeter frame to take part in resisting the bending moment of the lateral load acting on the structure by developing axial restraining forces in the windward and the leeward columns of the perimeter frame and forming a resisting moment.Most of the present analytical methods have studied the performance of outrigger braced structures neglecting shear deformation of the shear wall core and... 

Determining nonlinear dynamic behavior of structures is always one of the main goals of structure and earthquake engineers. The Modal Incremental Dynamic Analysis (MIDA) is one of the newest methods for analyzing the seismic behavior of structures. Indeed, this method has superseded the exact IDA method which is too complicated and prolix. Although, this method represents approximate results, high accuracy, fastness and low cost procedure made it an efficient and useful technique. Many researchers have used this method and investigated the accuracy of that and achieved proper results. Up to now no one has applied this method on structures which are equipped with dampers. In the procedure of... 

Existing design methods for steel frames has been improved over the last three decades in order to incorporate the behavior of semi-rigid steel connections in furtherance of frame design and since the analysis and design of structures is often done based on the assumption of completely rigid or pinned behavior,therefore, the actual behavior of connections and their modeling can help to understand the actual behavior of structures.Knowledge of the initial rotational stiffness of the connection is important for elastic analysis of structures. Investigations show that structures with semi-rigid connections have many features which are the causes to prefer these kinds of connections to the... 

To investigate the accurate performance of a structure, the knowledge of the way its connections function, is of great importance. Moreover, cognition of the actual behavior of connections which is often semi-rigid can lead to better apprehension of the actual and more accurate behavior of structures, whilst it is often considered to be pinned or fully-rigid.Therefore, in this study a new semi-rigid steel connection of beam to column will be introduced, and its behavior will be investigated using commercial finite element packages along with mathematical approximate modeling methods. One of the features of this connection is that its behavior mainly depends uponfolding of top and bottom... 

Iron is a common impurity in copper minerals. The presence of iron in hydrometallurgical copper PLS causes continuous reactions between Fe(II) and Fe(III) ions. In order to improve energy efficiency and product quality iron removal shall be done. In this study separation of iron from Sarcheshme copper leaching liquor containing 6 g/L Fe, was conducted by solvent extraction using D2EHPA in kerosene. Chloric acid solution was used to strip the loaded iron from organic phase. Results of extraction experiments designed by taguchi method showed 92.49% iron recovery and 2.44% copper extraction under optimum condition. Using same method for stripping experiments, it was found that variation of time... 

Steel plate shear walls (SPSWs) are popular lateral force resisting systems whose practical applications range from high seismic regions to medium and low seismic areas and wind load applications. The factors which make SPSW attractive include its energy dissipation capacity, excellent ductility, constructability, speed of construction compared to concrete shear walls, reduced architectural footprint compared to concrete shear walls, and increased inelastic deformation capacity as compared to braced frames and concrete shear walls.
In this research, characteristics and behavior of un-stiffened perforated SPSWs using non-linear finite elements software has been investigated. In order to...