Wasit Journal of Engineering Sciences

In recent years, the fields of robotics have witnessed major developments, and simulation tools have played an important role in facilitating research and development.

The WidowX250-6DOF robotic arm and the Rviz visualization tool are used in this study to look at how altering joint angles affects the position and orientation of the end-effector. The main goal of this study is to incorporate ROS on a Linux platform in order to give the widowX-250 a simulation environment. Important tasks like the application of forward, position/trajectory control and inverse kinematics should be enabled by this platform. ROS, together with Gazebo, RViz, and MoveIt, are crucial technologies for this project. The goal of this research is to gain a better understanding of how variations in joint angles impact the positioning and orientation of the robot\\\'s end-effector. The research helps to improve robotic arm control tactics and applications in many different industries, including manufacturing, automation, and robotics.

The multi-input-multi-output-antenna Scheme is regarded as the most promising method for next-generation wireless communication networks that employ millimeter-wave (mm-wave) frequencies and enable them to have a large information throughput. As a result of the large number of radio frequency chains, MIMO mm-wave technology has difficulty with energy consumption. The beam space MIMO (or BS-MIMO for short) reduces the total number of radio frequency components or chains (RF-Chains) without degrading performance significantly. Yeti, VS-MIMO restricts the number of clients that can be supported at the same time-frequency domain (cannot exceed the overall RF-chains number ). In order to cope with such problems, it has been intended to include the NOMA technique (which stands for Non-Orthogonal-Multiple-Access) with the concept of beam space to create the extra model of Non-Orthogonal beam space-MIMO (NOMA-BS-MIMO). With such a scheme the base station can support the service for more than one client (supposed to have correlated channels) through the same beam employing the same radio frequency chain, causing the total clients number greater than the number of employed radio chains in the system.

In this research, the Spectral Efficiency of a proposed Non-Orthogonal beam space-MIMO has been considered. More specifically, the research proposes and develops a simple iterative algorithm with near-perfect performance in terms of system Spectral Efficiency. To achieve rate balancing across users, the proposed method, SLNR-IV, employs the signal-to-leakage-plus-noise ratio (SLNR) and the intermediate value method. Considering algorithm validity and a particular parameter setting scenario, the proposed strategy improves bandwidth efficiency by around 15% in comparison to the conventional approach based on OFDM and Zero-forcing digital precoder.

Channel equalization is crucial to the efficiency of wireless network systems. To improve communication reliability and decrease computing complexity, 5G networks have made great progress with the help of deep learning (DL). When applied to 5G and future networks, deep learning has been proven to increase system performance while decreasing computational complexity. ZF is often used to acquire a channel equalizer because of its inexpensive cost and lack of statistical expertise; nonetheless, ZF has a large equalizer error. Because of the limitations of the Minimum Mean Square Error (MMSE) method, deep learning models provide a more convenient solution for solving the channel equalizer issue. Since deep learning may give a better performance-complexity trade-off, it can be used to enhance MMSE and ZF channel equalizers. Its generalization and resilience also make it an attractive tool for use in this context. To address the shortcomings of the ZF and MMSE equalizers, this thesis focuses on developing a DL-based channel equalizer. An Orthogonal Frequency-Division Multiplexing (OFDM)-based single-input-single-output (SISO) system is used to measure the DL-based equalizer\'s efficacy. Simulation results show that the DL-based channel equalizer can achieve at least a 3 dB gain in SNR over the MMSE equalizer for a SER = 10-3 in low and high selective channel models, respectively, validating the performance of the benchmarked equalizer using different frequency selectivity levels. Furthermore, the DL-based equalizer results in a drastic decrease in computing complexity in contrast to the ZF and MMSE equalization techniques.

It is a very importance, both theoretically and practically, to create an indicator system to evaluate the factors affecting construction productivity. This paper uses the expert consultation opinion, the questionnaire survey technique, and the documentary research methods to analyze the and prioritizing influencing factors on construction productivity and evaluate it from the aspects of construction, management, special circumstances, and building the evaluation index system of those factors. Based on the principle of Dempster-Schaffer evidence theory to make group decisions by constructing a comprehensive judgment matrix (to effectively gather the opinions of experts and solve the problem of conflicting opinions, then determine the weights of the indicators through the analytical hierarchy process,. In the end, an index system was obtained to evaluate the factors affecting construction productivity in Iraqi projects, including three first-level indicators/indicators, seven secondary indicators, and 56 third-level indicators, which provides theoretical guidance for project departments in order to study these factors. And work towards developing a system to effectively increase project productivity.

The two biggest issues we have are the energy crisis and global warming. Both issues are made worse by the use of traditional air conditioners. Therefore, numerous techniques were devised to overcome that, including solar ventilation, solar cooling, and solar thermoelectric modules. The most suitable choice was solar thermoelectric cooling because it was safe for the environment, provided a significant drop in car cabin temperatures, and avoided using hazardous refrigeration fluids.

The present numerical study aims to explore the effect of metal foam’s volume on the performance of a double-pipe heat exchanger in comparison with a smooth pipe (HXS). It used water as operating fluid at flow rate 2lpm, the outer stainless steel pipe has outer diameter (Do=60mm) and length (L=609.6mm), and inner copper pipe with outer diameter (do=20mm). The numerical simulation was conducted by ANSYS FLUENT 2020 R2 software and open-cell copper foam (CF) with porosity (0.9) was used. The cases considered in the analysis include a heat exchanger with a complete fill of copper foam (HXF), and a partial fill heat exchanger. The latter was made by inserting a complete rings of copper foam baffles (CFB) to decrease volume of a CF. Then, the baffles volumes was increased by increasing the thickness and their number. Three parameters were varied and their influence on performance evaluate criteria (PEC) were investigated. They are pore density (PPI), thickness of baffles (tc), and number of baffles (nob). Results showed that, heat transfer rate (Qave) and the pressure drop (∆p) increased with increase pore density, and well distribution of a CFB increase thermal performance while the pressure drop did not change with use same volume of CF.

The effect of subcooling inlet has a big effect of the flow patterns for the flow boiling through a microchannel. Higher subcooling lower mass flux will delay the nucleate boiling and vice versa. The water flow boiling inside a microchannel has been analyzed numerically. The microchannel depth was 0.24 mm while the length was 40 mm. The supplied heat fluxes were 500 kW·m-2, 1000 kW·m-2and 1500 kW·m-2 with mass velocities of 400 kg·m-2·s-1 and 800 kg·m-2·s-1. The degrees of subcoooling of inlet water were 5oC, 10oC, 15oC, 20oC, and 25oC. The results showed that the degree subcooling has a considerable impact on both the wall temperature and flow patterns. The rise in the degree of subcooling kept the nucleate flow boiling and retarded the development of convective boiling. In addition, there was a reflection point at which the impact of heat flux on the average of the convective coefficient of heat transfer was altered. The increase in the heat flux may lead to an increase or reduction in the average HTC with respect to the location of the reflection point. The reflection points were 7oC and 5oC for the mass velocities 400 kg·m-2·s-1 and 800 kg·m-2·s-1. Thus, both the degree of subcooling and the heat flux should be simultaneously considered when it comes to the enhancement of HTC during the flow boiling inside the microchannels.

In this work, a numerical study of a thermal performance of water flow inside a dimpled pipe. The effect of three types of dimples (circular, square and rhombus) studied in the numerical simulation. A commercial program called ANSYS was used to model the flow through a circular pipe .The three-dimensional governing differential equations of mass, momentum, and energy were used together with the (K − ε ) model to evaluate the impact of dimples on a turbulent flow and the velocity field. The study was carried out in the Reynolds number (Re) range (2500–15000). The research results demonstrate that the presence of a dimple on the pipe surface greatly increases the rate of heat transmission and the friction factor compared to a normal smooth pipe. Also, the numerical study demonstrated that the Nusselt number (Nu) in case of circular dimples at diameter (4 , 6 and 8) mm was (22, 28 and 43) % greater than the smooth surface. It is discovered that the improved pipe with circular dimples have a benefit for increased heat transmission efficiency compared with the square and rhombus dimples. Additionally , circular dimples have the ability to supply the lowest friction factor (f) when compared to other types of dimple. The pipe with circular dimples with D= 4mm , at Reynolds number 2500 provided the largest thermal performance criterion (PEC) value about 1.44.

In this study, we investigated Terasil blue dye absorption on modified rice husk through batch and continuous trials. In continuous mode includes experimental tests in an inverse fluidized bed teqnique at various times and under various operating conditions (bed height, initial concentration, and varying flow rate) were investigated. The effect of various factors like pH, contact time, agitation speed and particle size on the removal efficiency (%) the Terasil blue dye were thoroughly investigated. The maximum removal efficiency (%) was achieved up to pH 7.0. Removal efficiency (%) increased with increasing contact time. The maximum removal efficiency (%) was achieved @200 RPM (rate per minute). Increasing in the particle size caused decreased in the removal efficiency (%). In batch experiments the Freundlich, and Temkin models showed good agreement with R2 value while the Langmuir model had moderate agreement. The value of qe is 1.73 mg/g under specific conditions; the Langmuir model provides q-max of 0.0078 mg/g and K-L of 0.0801 L/mg.Ongoing tests conducted in an inverse fluidized bed offer valuable insights into the hydrodynamic behavior of the system.



The collected data effectively demonstrates the variations in pressure drops and bed heights. There is a positive correlation between bed height and fluid velocity, suggesting a significant association within the dynamics of fluidized beds.

Using the Internet, nothing is secure and as we are in need of means of protecting our data, the use of passwords has become important in the electronic world. To ensure that there is no hacking and to protect the database that contains important information such as the ID card and banking information, the proposed system stores the username after hashing it using the 256 hash algorithm and strong passwords are saved to repel attackers using one of two methods:

-The first method is to add a random salt to the password using the CSPRNG algorithm, then hash it using hash 256 and store it on the website.

-The second method is to use the PBKDF2 algorithm, which salts the passwords and extends them (deriving the password) before being hashed and stored on the website.

The results of the two methods are compared in terms of speed and resistance to attackers, then password attacks are analysed in addition to calculating the strength of the password, the time it takes for the user to log in, and the time required for the attacker to guess the passwords per second. The Wolfram Alpha is used to calculate the mathematic operations and system implementation was done by using IntelliJ IDEA with java FX.