Sharif Digital Repository

More than half a century has passed since the start of research on seismic liquefaction phenomenon in cohesionless soils, and various researchers has proposed different correlations for liquefaction prediction based on in situ tests. However, there still exists a great uncertainty in liquefaction prediction correlations, and liquefaction still occurs in different parts of the world. Hence, the main objective of this research is to reduce uncertainty in seismic liquefaction initiation correlations. While the technical literature indicates that soil resistance can alter due to liquefaction and shaking events and soil resistance after the liquefaction is not necessarily indicative of it prior... 

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,... 

The aim of this project is design and implementation of the “gradiometer RF SQUID base Vibrating Sample Magnetometer (VSM)”. Different sections of the system have been designed such as pick up coils, vibration system and electronic circuits. The piezoelectric crystal has been concerned for vibration system. At the first step, we have implemented the basic VSM system. In the basic system, voltage induces in two series opposite pick up coils and its output is recognizable via electronic circuits. At the second phase of the project, the electronic circuits of basic VSM system have been replaced with the RF SQUID gradiometer and its electronic circuits. Afterwards, the sensitivity and the gain... 

Activated Carbon as a highly efficient and low price absorbent has manifold functions in separation and absorption processes in liquid or gas phases. These applications in liquid phase include bleaching in sugar syrup, water and wastewater treatment and in gas phase utilizing them in gas masks and solvent recycling process. Wide variety of base materials could be used to produce activated carbon. For instance rare cellulose materials -wood, coconut shell, Pyrenees and agricultural wastes-, carbon materials-coal, petroleum coke, tar- and polymer materials- tires and plastics wastes- could be mentioned. In this thesis, feasibility of producing activated carbon based on using walnut, almond... 

Suspension system is one of the most influential components of vehicle in the area of stability and comfort. The suspension system is designed based on the use of the vehicle and stable characteristics. Obviously, being distant from the designed spots and applying various gates, its optimized performance is lost. Semi-active suspensions by changing their features get floating designed spots to be created and suspension system is always in optimum conditions through a suitable control. This research covers the efficacy of using damper Magneto Rheological which is called damper (MR) on the performance of vehicle suspension system in reducing vibrations. This damper is considered as a device in... 

A novel SPME fiber was prepared using sol-gel technology with ethoxylated nonylphenol as a precursor and used for development of a headspace solid phase microextraction coupled with gas chromatography-mass spectrometry method for quantification of 13 priority polycyclic aromatic hydrocarbons in water samples. The fused silica is the material that has recently been used as a substrate in sol-gel works for preparation of SPME fibers. Given that its drawbacks such as breakability and fragility which make the work tedious and time consuming¬, in this survey stainless steel wires were chosen as a substrate for coating the sol-gel film on them. The fibers made from steel are vary sturdy and aren’t... 

Since direct measurement of neutron energy, unlike measuring the energy of ionizing radiation, is difficult, and the use of indirect methods for detecting and measuring neutron energy with high resolution and acceptable efficiency are not possible, the neutron time of flight method is the only direct neutron energy spectroscopy method. This issue is considered and evaluated in two methods: direct and scattering neutron time of flight. For this purpose, we have considered the 241Am-9Be source. In this method, neutron velocity can be determined by measuring time. is the time for the neutron that travels at distance of . The next method is the dispersed neutron time of flight method, in... 

The Pulse Laser Deposition (PLD), Sputtering, Evaporation and Metal-Organic Chemical Vapor Deposition are the common methods for thin film fabrication. The mentioned methods are very costly for commercials application. Due to the importance of cost in large thin film fabrication, scientist tried to find a low-cost method. The low-cost non-hazardious Metal Organic Deposition (MOD), method which is based on chemical manufacturing method was developed. The type of the solvent and removal the destructive residual materials are the main challenge in this method. In this project, by utilizing acetyl acetone method, high quality MOD YBCO superconducting thin film has been fabricated and will be... 

The short-term expansion planning of the private utilities, as well as the emerging technologies such as photovoltaic panels (PVs), plug-in hybrid electric vehicles (PHEVs), cryptocurrency mining, and storage elements spread, make the long-term load estimation of distribution transformers (DTs) noticeably imprecise. In response, the number of overload and underload transformers is growing in recent years. The utilities normally analyze the loading of their DTs annually to determine the DTs, which should be replaced. The simplest, but expensive way is to substitute them with the newly purchased DTs. However, financial profit motivates the utilities to relocate in-service undersized and... 

Because of the inability of conventional methods to regenerate the infarcted part of the heart, regenerative medicine based on using scaffolds and hydrogels incorporation with cells and biological factors emerges as a promising approach. Micro-structures, especially hollow microcapsules created by the microfluidic system, has received a great deal of attention due to their inspired biomimetic structures, providing complete coverage cells, and preventing an immune response, consequently. This study aimed to use a microfluidic system to fabricate hollow microcapsules and investigate the behavior of rat cardiomyoblast cells (H9C2) along with exosomes within these structures. These structures'...