Sharif Digital Repository

High-frequency oscillations (HFOs) in brain electrical signals are activities within the 80–500 Hz frequency range that are distinct from the baseline and include at least four oscillatory cycles. Research indicates that HFOs could serve as potential biomarkers for neurological disorders. Manual detection of HFOs is time-consuming and prone to human error, making automated HFO detection methods increasingly necessary. These automated methods typically rely on the signal's energy within the HFO frequency band. Tensor decompositions are mathematical models capable of extracting hidden information from multidimensional data. Due to the multidimensional nature of brain electrical signals, tensor... 

Flow analysis in and out of the pressure-swirl injector in supercritical condition is investigated in this thesis. These injectors widely are used in different industries such gas turbine combustion chamber and liquid fuel rockets. Flow simulation in these injectors is so complex because of existence of gas core in axial region and high swirl and axial speeds in injectors. Unlike subcritical condition, droplet and ligament don’t form in supercritical condition so injector performance represents with two parameters including liquid film thickness in vortex chamber and liquid spreading angle. Mass flow, geometric constant, length and the distance between tangential inlet and injector head, are... 

In this experimental study, a series of wind tunnel tests were performed to examine the wake flow profile over three swept wings with sweep angles of 23, 33 and 40 degrees with similar aspect ratio at various conditions. The airfoil of wing was a NACA 6-series airfoil designed to provide a laminar flow on the front half of the airfoil. The tests, made at a mid aerodynamic chord Reynolds number of 8×〖10〗^5, covered an angle of attack range of -2 to 10 degree. The wing tip vortex effects are eliminated by placing an End-plate on the wing tip.The tests were carried out at two main section of wing and two various position from behind of wing. A total pressure rake and transducers was used to... 

Asparagainase is a therapeutic enzyme which has been a subject of research for decades. The enzyme catalyzes the hydrolysis of the amide group in asparagine and similar amides. Altering the substrate specificity and stabilization of this enzyme can increase its therapeutic properties. Moreover, asparaginases may be evolved to catalyze the hydrolysis of other similar compounds. These can be achieved through directed evolution and computational methods.In this study, the gene encoding L-asparaginase II enzyme from E. coli was amplified by polymerase chain reaction (PCR) and was cloned into an expression vector. The recombinant protein was expressed by an appropriate host secreting the... 

The quest for increasing the efficiency of internal combustion engines is going on since the invention of automobile in the world. Wear between cylinder and ring is one of the major parameters reducing the engine performance. So many parameters are affecting the wear losses. Temperature plays a key role on the severity of wear condition in internal combustion engines. In conventional cast iron cylinders, we are not able to increase the temperature from a defined level; one reason is that the wear rate on cylinder ring contact will increase excessively. One of the major benefits of using ceramic coating is their ability to withstand in higher temperatures, while having adequate hardness to... 

Prediction of shear plane angle is a way for prediction of the mechanism of chip formation, machining forces and so on. In this study, Merchant, Corrected Merchant, Lee and Shaffer, Lee and Shaffer with Built up Edge, Corrected Lee and Shaffer and Slip line theories are used for prediction of shear plane angles and cutting forces in machining of Al/SiCp metal matrix composite. The experimental cutting forces are compared with the calculated cutting force based on shear plane angles extracted from Merchant, Corrected Merchant, Lee and Shaffer, Lee and Shaffer with Built up Edge, Corrected Lee and Shaffer and Slip line theories. The variation of these cutting forces with cutting speed, feed... 

With advancement of science of aircraft design and limitations of traditional manufacturing methods, using new ones in order to improve efficiency is needed. Among those methods to improve structure efficiency are weight reduction or increase in strength. Increasing strength-to-weight ratio and reduction of weight could be achieved by using composite materials and topology optimization respectively. Manufacturing such parts with efficient design using traditional methods is hard or impossible. Additive manufacturing as a new technology which is being developed every day, can be a big help to aerospace industry. Considering the importance of strength-to-weight ratio in aerospace industry and... 

A global concern has arisen owing to rapid industrial development and population growth, resulting in energy scarcity and earth pollution. In this regard, developing green and sustainable methods for producing clean energy and solving environmental pollution problems have absorbed enormous attention. Among various auspicious strategies, semiconductor photocatalysis has been widely studied in recent years owing to its capabilities to obtain hydrogen as an energy carrier, to remove organic pollutants, and to reduce CO2 emission by converting solar energy into chemical energy. Recently, a metal-free semiconductor photocatalyst based on graphitic carbon nitride, g-C3N4, has received much... 

Recent success of Deep Learning models, resulted in their evergrowing application in many fields. However these models usually require huge datasets, which can sometimes be hard to collect. One of the challenges related to medical data, is the Batch Effect; Medical data is usually gathered through multiple experiments. Each experiment might have a slightly different conditions than the other, resulting a shift in the data related to that batch. Batch effects can have more severe impact during testing time, as the shift in the data distribution could be bigger. Many methods have been proposed to reduce or remove the effect of external conditions on data distribution.Deep Learning models have... 

Power amplifiers are used as the last block of transmitters. This block can be categorized as the one of most important part in communication systems. However, in transmitter systems which require high power to create stable link with the receivers, fabrication process like CMOS are unable to provide such level of power. Thus, designers employ another group of integrated circuits which names MMIC that offers this capability to designers. MMIC is the abbreviation of Microwave Integrated Circuit which is implemented in compound substrates like GaAs. Monolithic microwave integrated circuits enable the implementation of amplifiers in small size, large number, with high precision and appropriate... 

Platinum nanotubes were deposited inside the pores of polycarbonate template with the pore size of 200 nm by electrochemical methods. In this regard a solution containing of 0.05 M H2PtCl6 and 0. 1 M H2SO4 in doubly distilled water was utilized. The electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. It was observed that the process was conducted in several stages including; nucleation and growth in steady state regime. Furthermore, it was concluded that electrodeposition was affected by mass transport restriction and was controlled by a diffusion process. In this regard, all the voltammograms were shifted to more negative... 

Today Ethernet is the predominant technology for implementing Local Area Networks. Its privileges encourage service providers to extend Ethernet from Local Area Networks to Metropolitan Area Networks or even Wide Area Networks. Ethernet benefits such as low operational costs, well interoperability, plug-n-paly characteristic and rapid provisioning on demand make Ethernet ideal for Metropolitan Area Networks.But Ethernet by itself has some weakness like flat structure that makes it unfit for use in Metropolitan Area Networks. A suitable solution for taking advantages of Ethernet benefits in service provider network is using Ethernet in access network and applying multi-point to multi-point... 

Vehicular ad-hoc networks have attracted the attention of many researchers during the last years due to the emergence of autonomous vehicles and the safety concerns regarding their use in near future. One of the major applications in this domain is the usage of vehicle to vehicle communication for warning message dissemination in dangerous situations to prevent more damage. A number of schemes have been proposed regarding the selection of forwarding nodes in this application and there is a need for developing frameworks for analysis and comparison of the schemes in fair situation. Most of the proposed frameworks make use of simulation techniques for the analysis of schemes. However, due to... 

Paper and cardboard waste pulping consume large volumes of water, so the discharge of this effluent without proper treatment can have far-reaching environmental consequences. The color and variable COD concentration of wastewater in this industry make treating this wastewater complicated. Therefore, this study aims to reduce the COD of the wastewater treatment plant of a pulp and paper mill under different laboratory conditions to achieve environmental standards in Iran.In this study, coagulation-flocculation and the Fenton process on the wastewater entering the treatment plant were investigated first. It was found that coagulation and flocculation by 750-1250 ppm of alum coagulant and ten... 

Increasing population growth and scarcity of fresh water resources have created the challenge of water supply, especially in the Mena region. Thus, many countries in the region have turned to innovation in the development of high-energy seawater desalination technologies. Utilizing the waste heat of refineries in the desalination industry can reduce costs and preserve the environment. In this article, effective ways to use the waste heat of other flue recovery steam of Bandar Abbas oil refinery are investigated. The integration of the heat recovery system consisting of recuperative heat exchangers and heat pipes with thermal desalination plants is investigated by multi-stage flash and...