Engineering and Technology Journal

The user’s handoff is still an arguable issue that many mobile communication systems face, especially with the exploded growth of users and internet-based applications. There is a critical need for adequate quality of service (QoS) to meet the stringent requirements. This paper aims to study the overall performance and feasibility of several QoS mechanisms with the single-homed and multi-homed networks/nodes fluctuating resource availability. It investigates the adaptability of multi-interfaced multi-homed techniques to enhance the essential governing parameters, i.e., throughput, end-to-end latency, processing time, and jitter. Moreover, the paper introduces an interface selectivity technique for the multi-homed node to adopt the optimal interface, which offers the best services to explore the enhancements of the overall network performance. The overall results show how the introduced mechanism managed to keep the communication going on the multi-homed node. Furthermore, the results show that site multi-homing provides a better overall end-to-end latency over host multi-homing as it supports the entire network.

Although using a PV grid-tide system has many advantages, connecting the PV to the grid creates a new challenge at the power quality level. The PV grid-tide plant (250 kW), implemented at the Iraqi ministry of electricity building, was taken as a case steady to examine the power quality issue at various irradiance levels. The plant was described in detail and built using MATLAB2018b/Simulink. The developed system was examined at various irradiance levels. The results showed that an increased irradiance level leads to an enhancement in the power quality. The total harmonic distortion (THD) decreases with the increase of irradiance. Such behavior has a good impact on the power quality, where the (THD) is considered a crucial parameter in the power quality issue and increased irradiance level, leading to increased injected power to the grid. Up to the date of writing this study, the power quality effect of the installed (250 kW) PV grid-tied system on Iraqi grid utility was not previously studied, whether for the studied system or another PV grid-tied system installed in Iraq.

Graphene oxide synthesis by hummers method and reduction by the green chemical method using green tea. Preparation films with reduced graphene oxide (rGO) and Silver Nanoparticles (AgNPs) by a spin coating method. The preparation films and Nanomaterial characteristics with X-Ray diffraction (XRD) GO has a peak at (2θ = 11.22̊ ). While rGO has a wider peak at (2θ = 26.2̊ ). The (rGO +AgNPs) films have five obvious diffraction angles. In Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), flaky sheet (rGO), and spherical (AgNPs) with Nanosize about ~20 nm, the peaks of EDX indicated the presence of Carbon, silver, and oxygen. The energy gap was calculated from the absorbance spectrum and seemed to decrease with increasing AgNPs.

The importance and accuracy of the human visual system have led scientists and researchers to do their best to study it, know its problems, and how to treat them.
The eye lens tilt is possibly due to a specific accident such as a blow or the like. So, this manuscript was submitted to study the human eye lens tilting effect on visual performance and determine the tolerance tilt values. Using (ZEMAX-EE) software program and relying on the Liou and Brennan model Eye (LBME), one of the most accurate models for studying the eye, and some basic criteria used to describe the image formed in an optical system, such as Modulation Transfer Function (MTF), Root Main Square-spot size (RMSS), and simulated image including aberration, the study of the lens tilt effect on visual quality was conducted. The calculation of the area under the MTF curve was also used to determine the tolerance tilt values. Where the lens was tilted from (-5 to 5) degrees by (1 degree) on the (X and Y) axes, for zero decentering, with visible wavelength (0.486, 0.587, 0.656) µm, pupil diameter (2.5 mm), and field of view (5^o).The results were that vision worsened when the lens was tilted due to reduced MTF. Sagittal MTF was less sensitive than Tangential due to the nature of the lens structure. The area under the MTF curve results also proved that the tilt is less than (5) degrees does not affect the visual much, so it was necessary to determine the tilt tolerance values.It was concluded that the visual quality was inversely proportional to the tilt increase. Exceeding the tilt (5) degrees led to visual deterioration due to increased optical aberration where the tolerance tilt ranges were (± 5.1) degrees and (- 5.9 to 9) degrees on the (x and y) axes, respectively.

In recent years, electronic transformers and electronic devices (nonlinear loads) have increased. These loads are the source of harmonics (non-sinusoidal and distorted waves) and the interactive force that affects the performance of the power system network. Also, it badly affects the power factor and electrical energy on the scales of efficiency and quality. For this reason, a system called “Active Power Filters” has been adopted. It provides an effective alternative to traditional LC passive power filters. It can improve network performance by treating and reducing harmonics, improving power factor and quality, avoiding resonance between the filter and the network, and reducing reactive power. This paper presents a study on the shunt active power filters device and how to connect it to the distribution network and A review of the bathing control strategies in the methods of calculating current and power, methods of controlling the PWM device, the most prominent techniques for improving the PID control system, and the most prominent algorithms applied in that to improve the safety performance of the  Shunt  Active Power Filter (SAPF) on the one hand and to demonstrate the ability of different systems to compensate for THD on the other hand. APF performance fluctuates from one control strategy to another. It reduced (THD) between 0.9% and 13% in several control techniques applied with PWM. The aim of this paper is to illustrate the techniques applied to control the performance of the "Shunt Active Power Filter" to reduce THD