Sharif Digital Repository

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,... 

Generating real traffic and attacks for network equipment and applications are not yet considered a clear straight forward subject. To overcome this issue, we produce real traffic and then add some vulnerability attacks to it. This is an important step towards achieving security tests or evaluation methods which let us examine or assess intrusion detection (IDSs) features of a system.In this dissertation, we generate legitimate and anomalous traffic beside some attacks. Our study yields an implementation which is tested in real environment. We introduce a substantial method to generate DDoS attack in network and transport layers. We develop a software tool for this purpose. The performance... 

These days the usage of welded tailor blanks with sufficient stability and flexibility is accelerating rapidly in order to production of slighter parts and reduction of fuel consumption in transportation means. Therefore, the conjuncture of blanks by welding methods is highly considerable before forming and ultimate production. Friction Stir Welding is greatly appealing to industry as one of the newest methods of solid state welding in production of TWB blanks. In this research, the feasibility study of Friction Stir Welding of thin Al 1100 – H18 alloy blanks with 1.5, 2 and 2.5mm thickness has been evaluated first. After creation of sound welds with same thicknesses, Friction Stir Welding... 

The microstructure and wear performance of WC/Cu-Zn-Ni composite surface coating has been investigated using a combination of microscopy, hardness, and wear testing. The oxidation behavior of tungsten carbide hard metal in the temperature range between 600 and 900 ◦C was also researched. The oxidation mass gain of WC correlated almost directly with temperature as well as time. The particle of hard metal is surrounded by the α Cu+β Zn phase in the surface coating. The size of hard metal is almost unchanged from its original one. There exists an inter-diffusion zone at the interface of the hard metals and Cu-based matrix. The wear volume of the WC/Cu-Zn-Ni composite surface coatings increased... 

In this study, density, viscosity and surface tension of aqueous solution of Sulfolane, ( TEA+TMS+H2O) and (DIPA+TMS+H2O) systems were measured . Density, viscosity and surface tension were measured using pycnometer, Cannon – Fenske viscometer and Capillary rise method, respectively. Surface tension measurements of (DIPA+TMS+water) were carried out by the ring method using a LAUDR TD3 tensiometer,. The experiments were carried out in low concentrations and atmospheric pressure in the temperature range (70 - 30) . The obtained Data was modeled using empirical and thermodynamic models. Density calculation was done using the Setchenov and Redlich – Kister models.and the results indicated that... 

The need to build underground structures like tunnels, oil reservoirs are increasing and it requires a good knowledge of behavior of mass rock, exact data and parameters for safe and economic design. Filling materials which usually transfer with water into the joints reduce shear strength of joints significantly and change the behavior of the joints. To evaluate shear behavior of filled joints, 24 tests were conducted with large scale direct shear test apparatus on model rock joints with a regular “saw tooth” surface profile with the dimensions of 15cmx15cmx18cm. Filled material had specified specifications like particles size and strength parameters.
Infill thickness, moisture content... 

One of the most important conditions in weak rock masses with high overbuerden which causes problems in the tunnel construction, is squeezing condition. This is actually defined as increases in the shear deformation of the rock element, when the element is under constant deviatoric stress. Qomroud water tunnel with a length of 36 km and a drilling diameter of 4.5 meters deliveres water from the branches of the Dose to the Golpaygan and Qom. Because of a high overbuerden and existence of schist, slate, clay limestone zones, studing of squeezing potential,prediction of convergence of tunnel wall and lining pressure in this tunnel is very important.In this research, we stuied the 25th to 35th... 

The rapid pace of development of nanoscience and nanotechnology and their applications in various fields have made the study of materials in smaller scales more important than any time ever. Having an insight of materials’ microstructure and the mechanism of different phenomena in the atomic scale will be very beneficent in designing new and advanced materials or modifying the current manufacturing processes. Since molecular dynamics (MD) method has been well known as a mean of studying materials in atomic scale, it has been used in this study to investigate two different phenomena. The selection of the appropriate interatomic potential is of great importance in MD; Embedded Atom Method... 

In this thesis, combustion of liquid fuel spray under the condition of hot and diluted oxidizer, has been investigated. To this end, a novel type laboratory-scale test rig was designed to study the physics governing the MILD-Spray combustion conditions with an applied approach. The underlined test rig eliminates the operational problems of its predecessor test stands and is used for a heavier fuel with much more complex chemical composition (kerosene). The test section is axially symmetrical, in which the fuel is injected by a pressure-swirl atomizer in the direction of hot and diluted co-flowing air. With the use of the aforesaid test rig, the effect of variables such as oxygen... 

Monitoring driving behaviors of drivers, would avoid their dangerous behaviors and remarkably raise the safety. Nowadays real-time supervision is considered as one of the modern methods of controlling driving behaviors. Previously, due to expensive costs of required equipments and other restrictions, this kind of supervision hasn't been considered fairly. Nowadays increasing usage of smart phones, which contain multiple sensors, enables this type of supervision with lower costs. In the present study we would present some models, to assess the driving behavior via smart phone sensors such as accelerometer, gyroscope and rotation vector  

In practice, structures made of concrete are full of cracks. The strength of concrete is mainly determined by the tensile strength, which is about 10% of the compressive strength. As long as cracking in concrete is unavoidable, we have to try to minimize their detrimental effects. This objective can be achieved by resisting (or limiting) propagation of existing cracks. Because of this, reinforcement (mostly steel) is used to increase the carrying capacity of the material and to control the development of cracks. Concrete structures that fail, already shows a large number of large and small cracks before their maximum carrying capacity is reached. The failure of concrete can be characterized... 

The purpose of this research is to monitor the health of structures using the updated finite element model, in which digital images are used to optimize the numerical model. Structural Health Monitoring (SHM) is always an important and significant issue that has attracted the attention of many researchers in recent years. In general, some researches have been conducted in this field using physical sensors that provide discrete data to the system for analysis. Using cameras to monitor the structure makes it possible to extract continuous and integrated data from the structure using digital images, which is a significant advantage compared to physical sensors.In this research, a steel...