Comparison of Prediction Programs for Short Wave Circuit Link from Iraq to Test points on Both Earth Hemispheres during Solar Minimum

This paper compare the accurecy of HF propagation prediction programs for HF circuits links between Iraq and different points world wide during August 2018 when solar cycle 24 (start 2009 end 2020) is at minimun activity and also find out the best communication mode used. The prediction programs like Voice of America Coverage Analysis Program (VOACAP) and ITU Recommendation RS 533 (REC533 ) had been used to generat HF circuit link parameters like Maximum Usable Frequency ( MUF) and Frequency of Transsmision (FOT) .Depending on the predicted parameters (data) , real radio contacts had been done using a radio transceiver from Icom model IC 7100 with 100W RF power, tuner box and homemade dipole antenna of 10 m length and 8m height above ground. From correlation between the predicted data and observed data the result was not accurate .

Evaluation of the Main Causes of Diesel Engine Injector Failure using Fault Tree Analysis

This paper is based on the application of the root cause analysis principle of diesel engine injector failure in diesels Haditha station. The maintenance of the diesel engine injector contains many problems that lead to the injector stopping; several reasons lead to such Problems. Fault tree analysis (FTA) is one of the most widely used methods in the industrial sector to perform reliability analysis of complex engineering systems. A fault tree is a logical representation of the relationship of primary/basic events that lead to a given undesirable event (i.e., top event). This research aims to present the (FTA) technology and how to use it in analyzing the causes of problems that lead to the injector stop working, and how to calculate the probability of occurrence of such problems. Implementation of FTA based on the probabilities of the causes under the top event and canalization lead to the calculated probability value (0.80). The plant management can define a specific plan to reduce these problems, because failure of an important engine part (injector) with such a large value leads to long downtime hours compared to operating hours.

Analysis and Evaluation of a Quasi-Passive Lower Limb Exoskeleton for Gait Rehabilitation

Using lower limb exoskeletons in healthcare sector like for rehabilitation is an important application. Lower limb exoskeletons can help in performing specific functions like gait assistance, and physical therapy support for patients who are lost their ability to walk again. Since active lower limb exoskeletons require more complicated control instrumentation and according to the limitations of the power/weight ratio that arises in such exoskeletons, many quasi-passive systems have developed and employed. This paper presents the design and testing of lightweight and adjustable two degree of freedom quasi-passive lower limb exoskeleton for improving gait rehabilitation. The exoskeleton consists of a high torque DC motor mounted on a metal plate above the hip joint, and a link that transmit assistance torque from the motor to the thigh. The knee joint is passively actuated with spring. The action of the passive component (spring) is combined with mechanical output of the motor to provide a good control on the designed exoskeleton during walking. The results show that muscles' efforts on both the front and the back sides of the user's leg were decreased when walking using the exoskeleton with the motor and spring.

صمام تحكم اتجاهي يكون مغلقا في العاده

نبذة مختصرة. تم تصميم هذا الصمام للاستخدام في صمامات التحكم الاتجاهية ، وذلك باستخدام صفات السائل المغنطيسي الريولوجي ، وتم إنشاء الاتصال المباشر بين المجالات المغناطيسية وطاقه السوائل الذكيه من دون استخدام اجزاء المتحركة كالبكرة. للوصول إلى أفضل تصميم ، تم تشغيل المحاكاة باستخدام برنامج(FEMM) لتحليل العناصر المحدودة لصمامات الرنين المغناطيسي. تم الحصول على أفضل أداء للصمام باستخدام صمام تحكم اتجاهي مغلق في الحالة العادية ،كذلك نتائج المحاكاة التي تكشف عن كثافة التدفق المغناطيسي المثلى في حالة عدم وجود التيار وفي حالة تسليط التيار، بالإضافة إلى الضغط الأمثل . أخيرًا ، أثبت صمام فعاليته في التحكم باتجاه وسرعة المشغلات الهيدروليكية بشكل متناسب ، ويسمح التصميم الجديد باستبدال الصمامات الهيدروليكية لتكون أصغر واقل تعقيد.

Robust Computed Torque Control for Uncertain Robotic Manipulatorss

This paper presents a robust control method for the trajectory control of the robotic manipulator. The standard Computed Torque Control (CTC) is an important method in the robotic control systems but its not robust to system uncertainty and external disturbance. The proposed method overcome the system uncertainty and external disturbance problems. In this paper, a robustification term has been added to the standard CTC. The stability of the proposed control method is approved by the Lyapunov stability theorem. The performance of the presented controller is tested by MATLAB-Simulink environment and is compared with different control methods to illustrate its robustness and performance.

Simulation of a Self-Balancing Platform on the Mobile Car

In the last years, the self-balancing platform has become one of the most common candidates to use in many applications such as flight, biomedical fields, industry. This paper introduced the simulated model of a proposed self-balancing platform that described the self–balancing attitude in (X-axis, Y-axis, or both axis) under the influence of road disturbance. To simulate the self-balanced platform's performance during the tilt, an integration between Solidworks, Simscape, and Simulink toolboxes in MATLAB was used. The platform's dynamic model was drawn in SolidWorks and exported as a STEP file used in the Simscape Multibody environment. The system is controlled using the proportional-integral-derivative (PID) controller to maintain the platform leveled and compensate for any road disturbances. Several road disturbances scenarios were designed in the x-axis, y-axis, or both axis (the pitch and roll angles) to examine the controller effectiveness. The simulation results indicate that that the platform completed self-balancing under the effect of disturbance (10° and -10°) on the X-axis, Y-axis, and both axes in less than two milliseconds. Therefore, a proposed self-balancing platform's simulated model has a high self-balancing accuracy and meets operational requirements despite its simple design.

Phytotoxicity of Salvinia molesta in Diesel Exposure

Phytoremediation is one of the methods to remove various types of pollutants from water and soil using plants. Salvinia molesta, an aquatic plant, is chosen in this study to determine its ability to degrade diesel as the pollutant in synthetic wastewater with different diesel concentrations (0, 8,700, 17,400, and 26,100 mg/L) for 14 days. Total petroleum hydrocarbon (TPH) has been used as an indicator to represent diesel concentration variation in wastewater. Degradation of TPH was 85.1% for diesel concentration of 8,700 mg/L, compared with only 53.9% in the corresponding control without plant. While, acute toxicity on S. molesta exposed in diesel concentrations of 17,400 and 26,100 mg/L was observed and eventually had caused the plants to die after 14 days of exposure. Additionally, throughout the phytotoxicity test, the biomass of S. molesta was found to fluctuate confirming inhibition on plant to survive with diesel contaminated water compared with the corresponding control without contaminant. Based on the results obtained it is suggested to decrease diesel concentration less than 8,700 mg/L in future study due to insolubility of diesel in water and the toxicity to the aquatic plants

Optimization of Cutting Parameters for Milling Process of (4032) Al-Alloy using Taguchi-Based Grey Relational Analysis

The objective of this work is to study the influence of end milling cutting process parameters, tool material and geometry on multi-response outputs for 4032 Al-alloy. This can be done by proposing an approach that combines Taguchi method with grey relational analysis. Three cutting parameters have been selected (spindle speed, feed rate and cut depth) with three levels for each parameter. Three tools with different materials and geometry have been also used to design the experimental tests and runs based on matrix L9. The end milling process with several output characteristics is solved using a grey relational analysis. The results of analysis of variance (ANOVA) showed that the major influencing parameters on multi-objective response were spindle speed and cutting tool with contribution percentage (52.75%, 24%), respectively. In addition, the optimum combination of end milling process parameters was then validated by performing confirmation tests to determine the improvement in multi-response outputs. The confirmation tests obtained a minimum (surface roughness and micro-hardness) and maximum metal removal rate with grey relational grade of 0.784 and improvement percentage of 2.3%.

The The Application of Virtual Reality to (Mechatronics Engineering) by Creating an Articulated Robotic Work Cell Using EON Reality V9.22.24.24477

Virtual reality, VR, offers many benefits to technical education, including the delivery of information through multiple active channels, the addressing of different learning styles, and experiential-based learning. This paper presents work performed by the authors to apply VR to engineering education, in three broad project areas: virtual robotic learning, virtual mechatronics laboratory, and a virtual manufacturing platform. The first area provides guided exploration of domains otherwise inaccessible, such as the robotic cell components, robotic kinematics and work envelope. The second promotes mechatronics learning and guidance for new mechatronics engineers when dealing with robots in a safe and interactive manner. And the third provides valuable guidance for industry and robotic based manufacturing, allowing a better view and simulating conditions otherwise inaccessible.

Modeling and Simulation for Performance Evaluation of Optical Quantum Channels in Quantum key Distribution Systems

In this research work, a simulator with time-domain visualizers and configurable parameters using a continuous time simulation approach with Matlab R2019a is presented for modeling and investigating the performance of optical fiber and free-space quantum channels as a part of a generic quantum key distribution system simulator. The modeled optical fiber quantum channel is characterized with a maximum allowable distance of 150 km with 0.2 dB/km at =1550nm. While, at =900nm and =830nm the attenuation values are 2 dB/km and 3 dB/km respectively. The modeled free space quantum channel is characterized at 0.1 dB/km at =860 nm with maximum allowable distance of 150 km also. The simulator was investigated in terms of the execution of the BB84 protocol based on polarizing encoding with consideration of the optical fiber and free-space quantum channel imperfections and losses by estimating the quantum bit error rate and final secure key. This work shows a general repeatable modeling process for significant performance evaluation. The most remarkable result that emerged from the simulated data generated and detected is that the modeling process provides guidance for optical quantum channels design and characterization for other quantum key distribution protocols.