Sharif Digital Repository

High performance concrete has a compressive strength of more than one hundred and twenty MPa. The effect of steel fibers on the flexural fracture of this type of concrete has been studied, but the mechanical behavior of fracture of this material has not been fully studied yet. In this research, the effect of different percentages of propylene fibers on the mechanical properties of reinforced concrete will be investigated experimentaly. For this purpose, beam samples with dimensions of 40*10*10 cm, which had an initial notch with a depth of 3 cm in the lower middle of it, have been tested to investigate the effect of fiber percentage on how the crack propegate and the sample breaks. It is... 

Change detection involves comparing images of a specific area taken at different times to identify the key changes that have occurred over time. It is critically important in the field of remote sensing, with applications spanning urban planning, disaster monitoring, and environmental conservation. However, challenges such as varying weather conditions and lighting in satellite images taken at different times, as well as the presence of non-target changes, can make this task challenging. In this research, we will focus on changes in land-use, particularly in building infrastructure, which is crucial for urban development planning. Moreover, since change detection does not specify the type of... 

Supply chain consists of many important processes that are critical to be analyzed in order to enhance effectiveness and efficiency of the whole organization. This survey presents a state-of-the-art approach for evaluating the health of supply chain processes by conducting a structure based diagnostic methodology. The proposed method is conducted in an Iranian automotive manufacturer and results are validated based on internal documents. The results of assessment can be used to improve supply chain performance by suggesting various projects. Finally different analysis like theme analysis is performed on extracted diagnosis and on suggested projects  

One of the major challenges in construction of rubber modified asphalt mixtures is determination of mixing and compaction temperature (MCT). In order to estimate MCT according to Superpave volumetric mix design procedure, a temperature-viscosity relationship for the binder should be developed using ASTM D2493. This approach provides reasonable temperatures for unmodified binders which are Newtonian fluids at high temperatures and their viscosity is independent of shear rate. However, this method often yields excessively high temperatures for modified binders which exhibit non-Newtonian pseudoplastic behavior. The reason is that viscosity of modified binders depend on not only temperature but... 

One of the applications of signal digitization is its use in nuclear spectroscopy and in particular gamma ray spectroscopy. Parameters such as pulse amplitude and formation, pulse shrinkage correction or reduction, and pulse sampling are performed by the amplifier circuit and MCA. Such algorithms have advantages such as real-time pulse height analysis, high flexibility and significant cost reduction.Therefore, in this project, an attempt has been made to design a pulse analyzer system using electronic circuits and a computer ADC sound card. Optimal system will detect, amplify and shape the detector input signal, reduce the effect of pulse accumulation, count the number of pulses, and so... 

Today, lots of vulnerabilities are discovered by researchers who are analyzing the software. Some researchers study these discovered vulnerabilities and find new ones that are similar to them. So they need to first characterize each previously discovered vulnerability and extract the vulnerable context of the program, then extract new vulnerabilities based on that. Some vulnerabilities are emerging because of developer mistakes in the implementation phase. Software developers use different function calls to do the goal of the program. Incorrect invocation for functions can lead to critical vulnerabilities. Our investigation shows that the root cause for some vulnerabilities is incorrect... 

Sensors are one of the most vital instruments in Nuclear Power Plants (NPP), and operators and safety systems monitor various parts of the NPP and control transients by analyzing the values reported by the sensors. Failure to detect malfunctions or anomalies in them would lead to catastrophic consequences. A new approach based on thermo-hydraulic simulation by RELAP5 code and Feed-Forward Neural Networks (FFNN) is given to detect faulty sensors and estimate their correct value which are two main objectives of the current study. This approach consists of two main parts; The first part, Fault Detection Hyper Block (FDHB), responsible for detecting faulty sensors, and the second part,... 

The primary purpose of acidizing operations in the oil and gas industry is to enhance hydrocarbon production. Acidizing has been a common and conventional method for years, especially when production engineers face issues like declining reservoir pressure leading to reduced production rates. Initially, the treatment solution is referred to as matrix acidizing. In acidizing operations, different additives are combined with the acid to control its behavior in the reservoir. These additives may include iron control agents, corrosion inhibitors, friction reducers, and more. Incompatibility among these additives, the acid, and reservoir fluids can lead to severe damage to the reservoir.... 

The goal of this research is the simulation of the annular combustion chamber of the turbine engine utilized by liquid fuel. The achievement to this goal will lead to create numerical tools for parametric study, analysis and combustion chamber designing.For this reason simple geometry has been considered. This simplicity of geometry causes to facilitate in parametric study and decrease in saving time for modeling and meshing. This combustion chamber is a simplified model of engine CF6. In recent study, the k – ε realizable model has been used for turbulence modeling. For non-adiabatic condition, chemical reaction is dissolved by utilizing probability density function along with laminar... 

During the last few years, the study of urban environment structures is considered as a research field of interest in remote sensing. In satellite observations of the earth's surface, continuous imaging in terms of time and space has caused the remote sensing technique to be proposed as a useful and efficient tool for the analysis of urban areas. Obtaining quantitative spatial information from the urban environment in fields such as determining the height of buildings plays an essential role in urban planning, monitoring damage to buildings, establishing communication bases and digital cities. During the last two decades, the use of Tomosar approach in order to reconstruct the structures of...