Tikrit Journal of Engineering Sciences

The research strategy focuses on the effect of connecting a STATCOM to mend critical-clearing-time (CCT) for the studied system and its transient stability. This paper targets to connect STATCOM in two situations, grouped and distributed. The first situation connects STATCOM at one placement with 100 MVAR reactive power while the second situation connects two STATCOMs at two different placements with the value 50 MVAR for each one and 60 MVAR,40 MVAR in another case. It has been found through this research that when distributing the necessary compensation capacity to more than one static synchronous compensator better than from combined them in one compensator in improving the CCT. It used MATLAB / ver.2017 for simulation of our studied system (IEEE-9 nodes).

Copper-matrix composites have received a lot of attention and are used widely in various applications, such as electronics, machinery, automobile, military and aerospace; because of their remarkable electrical conductivity, high thermal conductivity and excellent mechanical properties. Among these are copper-iron composites which found many engineering applications due to the role of Fe in enhancing the mechanical properties of these composites beside its low cost. However, Fe addition reduces electrical and thermal conductivity therefore, binary Cu-Fe composites are not suitable for applications where these properties are the main requirement. Many studies have been done to enhance these properties by the addition of alloying elements. The present work aims to study the effect of adding Nano Ag on mechanical and physical properties of Cu-10 wt% Fe composites prepared by powder metallurgy technique. The results showed the effectiveness of Nano Ag in enhancing both mechanical and physical properties of Cu-10 wt% Fe composite. It is found that bulk density, electrical conductivity, and thermal conductivity have been increased by 1.19%, 46%, and 46% respectively on adding 5% Nano Ag. Hardness and compression strength have been increased by 17.3% and 32.8% respectively by adding 4% Nano Ag, while wear rate was reduced by 13.4% by adding 4% Nano Ag.

These days, homes include a variety of electrical devices that are important to families for accomplishing daily tasks. These devices are powered by electricity and in some cases, require a lot of power consumption. Home users must control these devices manually by switching them ON/OFF; this exposes them to potential electric shock and can give rise to other dangerous situations. This paper presents a new approach for creating an electrical system that makes it easy to control household domestic appliances via short message service from a smartphone device. In this manner, users can be provided with a relaxed and safe approach to using electrical devices. The result of this work, users can access to the home devices easily and interact with them without any problem of electrical shock and personal effort.

With increase in the population, the number of registered vehicles has dramatically increased over all the world, and this leads to a high rate of traffic accidents on the roads. Therefore, in order to prevent such accidents, an Intelligent Transportation Systems (ITSs) is needed to be installed to notify drivers of obstacles in advance. Recently, the Internet of things (IoT) evolves the vehicular communications and covers this technology under the Internet of vehicles (IoV) application. IoV is a new field for the automotive industry and a significant part of the smart cities. However, protecting the privacy of vehicle's location is the most challenging subject in the vehicular communication, as because it threatens the personal life of drivers. This paper provides cooperation and radio silence strategy in mix zone (CRSMZ) to protect location privacy of vehicle in IoV. The strategy implements either cooperation or radio silence depending on the speed of the vehicle while it is in mix _zone. The simulation results show that CRSMZ is an efficient strategy to protect location information of vehicle drivers. CRSMZ outperforms the existing strategies in terms of mean of the number tracker confusion, continuous tracking period and max of the entropy.

Nano-sheet transistor can be defined as a stacked horizontally gate surrounding the channel on all direction. This new structure is earning extremely attention from research to cope the restriction of current Fin Field Effect Transistor (FinFET) structure. To further understand the characteristics of nano-sheet transistors, this paper presents a review of this new nano-structure of Metal Oxide Semiconductor Field Effect Transistor (MOSFET), this new device that consists of a metal gate material. Lateral nano-sheet FET is now targeting for 3nm Complementary MOS (CMOS) technology node. In this review, the structure and characteristics of Nano-Sheet FET (NSFET), FinFET and NanoWire FET (NWFET) under 5nm technology node are presented and compared. According to the comparison, the NSFET shows to be more impregnable to mismatch in ON current than NWFET. Furthermore, as comparing with other nano-dimensional transistors, the NSFET has the superior control of gate all-around structures, also the NWFET realize lower mismatch in sub threshold slope (SS) and drain induced barrier lowering (DIBL).

This paper is a study of the dynamic behavior of the double effect evaporator on the basis of energy and material balance under unsteady state conditions inside the evaporator. The simulation process was based on a model for the intensification of tomato juice. The mathematical model was used to study the effect of operational conditions, namely, the temperature of the feed, the flow rate of the feed, and the feed concentration. The dynamic behavior of the open system was studied by measuring the temperature response of the evaporators to the change of the staging function in the temperature of the feed, the feed flow rate and the feed concentration in the rate of (±10%, ±20%).The proportional-integral-derivative and model predictive controllers were applied to solve the difficult problem by determining the best operational conditions and avoid a sharp increase in temperature. Two methods are tested to control a wide range of operating conditions and simulation results show that there is good accuracy. The MPC controller is more accurate than the PID control and faster to reach the constant value.

In this research, a computer-aided drawing system of spur gear was developed. An auto LISP programming language embedded within the AutoCAD design package was used to develop a new program to create a 3D model of a spur gear in two main stages. In the first stage, the developed program of spur gear allows automatic 2D spur gear drawing generation using the technique that depends on the half tooth thickness at the pitch diameter. In the second stage, inner profiles of a 2D spur gear views are used to create a 3D model of a spur gear. The developed program helpful for the user in drawing the spur gear modelling, due to less work and time to be spent when compared with the conventional approach, and it also improves a high degree of accuracy of spur gear modelling. The spur gear resulting from the prepared gear drawing system can also work with other popular CAD software.

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively.

The behavior of reinforced concrete members under torsional loading has interested many researchers during the last decades. These researches focused mainly on the response of reinforced concrete beams at different reinforcement conditions and the size effects. On the other hand, the behavior of concrete plates or slabs has not been investigated clearly under pure and/or combined torsional loading. In the present study, nine reinforced concrete plates were prepared and tested under pure torsion. Effect of steel reinforcement ratio and size change was studied and they have a great effect on the plated strength, capacity, stiffness and ductility. As stated by torsion theories of reinforced concrete beams, the torsional strength of slabs was upgraded also with increasing in cross section and transverse reinforcement ratio.

Voltage collapse in the power system occurs as a result of voltage instability, thus which lead to a blackout, and this is a constant concern for network workers and customers alike. In this paper, voltage collapse is studied using two approved methods: the modal analysis method and voltage stability indices. In the modal analysis method, the eigenvalues were calculated for all the load buses, through which it is possible to know the stability of the power system, The participation factor was also calculated for the load buses, which enables us to know the weakest buses in the system. As for the Voltage stability Indices method, two important indices were calculated, which are: Fast Voltage Stability Index (FVSI) and Line stability index (Lmn). These two indices give a good visualization of the stability of the system and the knowledge of the weakest buses, as well as the Maximum load-ability of the load buses. The above mentioned two methods were applied using software code using MATLAB \ R2018a program to the IEEE 30-Bus test system. In the modal analysis, the buses which have the maximum participation factor are 26, 29, and 30 this indicates that they are the weakest in the system. as well as in the voltage stability indices. These buses have the lowest maximum load ability which demonstrates the possibility of using both methods or one of them to study the voltage collapse.