Tikrit Journal of Engineering Sciences

To meet the high throughput demands, the 3rd Generation Partnership Project has specified the low-density parity check (LDPC) codes in the fifth generation-new radio 5G-NR standard with rate and length compatibility and scalability. This paper presents an extensive performance evaluation and enhancement of LPDC using the protograph-based construction defined in the 5G-NR standard. Firstly, the protograph-LDPC with layered offset min-sum (OMS) decoding, polar with successive cancellation list (SCL), and block turbo code are implemented and compared. Puncturing and shortening are applied to maintain block length at 1024 and code rate at 1/2 for all codes for comparison fairness. The results showed that P-LDPC outperforms its counterparts in terms of bit/ frame error rate (BER/ FER) behavior for given signal-to-noise ratios. Then, different P-LDPC settings were realized to study the effects of base graph selection (Graph1 or Graph2), code rate change (1/3 - 2/3), and block lengths increase (260 – 4160 bits). The simulation outcomes proved that BER performed better for lower coding rates or higher block lengths. Furthermore, P-LDPC behavior was examined over a Rayleigh flat-fading channel to achieve a 12.5 dB coding gain at 0.001 BER compared with uncoded transmission.

The output of three-phase induction motors (3IM) is adversely affected by voltage imbalance. This work analyzes and estimates the output of a 3PIM operating on a balanced supply while contrasting it with a "single phasing" case. Simulation additionally makes use of MATLAB /SIMULINK. The effects of single phasing on a 3PIM's performance for system rerating are suggested. An example was given using a 4 kW 3PIM. It is not a big problem; however, it should be considered if a three-phase motor is purposely connected to a single-phase source or whenever a three-phase source loses one of its phases due to a fault. When a three-phase motor operates in a single-phase, the motor will continue to try to run the load until it is destroyed or the protective components remove the motor from the line. The outcome of single phasing is an increase in phase currents, which causes overheating and damage to the motor. A downline on the distribution grid or a blown pole upper fuse might cause a phase loss on a three-phase line. A single-phase overload condition that causes one fuse to blow or a device breakdown inside the end-user facility may also result in a single-phase loss.

Due to the serious wizards that industrial waste causes to humans, animals, and plants, besides the fact that wastewater from refineries contains many harmful compounds and that this type of industry is prevalent in most countries, the issue of protecting the environment from industrial waste is importance at the recent time. The organic contaminants elimination from the wastewater connected with the Iraqi refinery at Qayyarah served as our case study. The chemical oxygen demand (COD) was the organic contaminants measure. A titanium electrode (cathode) and an aluminum electrode (anode) were combined with the electrocoagulation and Photo-Fenton-processes. Using a Mini Tab program, the Taguchi method Utilizing statistical techniques, successfully obtained the outcomes and final values. The most effective removal of COD was 90.148. With a standard deviation of 2.651, the best conditions for this experiment were as follows: The time required to achieve this removal efficiency was 50 minutes, 8 pH, 400 mg/L of hydrogen peroxide, 20 mg/L of ferrous sulfate, and a current density of 15 mA cm-2. Through ANOVA analysis of this process, it was found that the current density (C.D.) significantly influenced the removal efficiency, affecting it by 47.79%, followed by the electrolytic solution effect by 18.31%, and the hydrogen peroxide and ferrous sulfate concentrations effect by 12.55% and 2.36%, respectively. Also, a mathematical equation was found to describe the studied case. The reaction kinetics were also investigated, and the reaction rate constant (cm/s) was determined at ideal conditions, with km = 6.60546 x 10-5.

This research experimentally investigates the flexural behavior of rectangular hollow flange cold-formed steel I-beam (RHFCFSIB) under two concentrated loads at the same distance from the support. All specimens were at a constant clear span of (L=1500mm), a constant beam specifications (t=4mm) web, flange thickness (h=300mm) for beam′s depth, and flange width of (bf=150mm). The connecting distance between the bolts, i.e., connects the web to the flanges, was (L/6), and eight stiffeners for each beam were placed under the load bearing points and at the support points on each side. The experimental program included assembling the parts to make beams and testing four specimens under two-point loads. The major parameters adopted in the current research included the flange depth, i.e., hf=30,60,90, and 120mm. The results showed that the beam with a flange depth of 30 mm had a higher ultimate load than other beams; however, it was the highest beam deflection. The beam with a flange depth of 120mm was the best section as a flexural member. The ultimate capacity of this beam increased by 15.34% and 6.4% compared to beams with flange depths of 60mm and 90mm and decreased by 12.9% compared to a beam with a flange depth of 30 mm. The maximum deflection at beam mid-span with a flange depth of 120 mm decreased by 53.8%, 44%, and 19.94% compared to beams with flange depths of 30 mm, 60mm, and 90mm, respectively. Therefore, the flange depth significantly influenced the flexural behavior by increasing the flange depth. Also, the ultimate capacity increased, and the deflection was reduced. The main conclusions drawn from the study were discussed and summarized. The research showed that the Hollow flanged sections gave the best results for flexural behavior.

Braced excavation is one of the important systems used to support soil from collapse during excavation. A braced excavation system may be exposed to seismic load and undergoes more forces through the significant vibration of the surrounding soil in addition to the static and lateral loads of soil and nearby structures. The investigation of the braced excavation under the effect of earthquake behavior is still limited or poorly described. Further, this paper presents a numerical study to evaluate the vertical settlement and horizontal displacement of sheet pile wall embedded in silty clay soil in Baqubah city under the influence of the acceleration time history of the 1940 El-Centro earthquake. The study utilized the software PLAXIS 3D. A three-dimensional analysis of the braced system with dimensions of 14m×6m and an excavation depth of 7m was achieved. Three levels of strut and wale layers were used, and five struts for each level. The penetration depth for the sheet pile wall was 9m. The study showed that the El-Centro earthquake laterally moved the braced excavation system as a block mass due to the existence of the excavation system in soft silty clay. The lateral displacement reached approximately 150mm. The differences in lateral earth pressure on sheet pile wall depth a few seconds before and after the earthquake were very small.

The present study explores the guidance of a robotic arm along a predefined path by implementing an optimal fuzzy fractional order PID controller-based control strategy. This method serves as a means to address the nonlinearity and unpredictability of the robotic manipulator, contingent upon the fuzzy logic controller's specifications and the employment of a clonal selection algorithm. The dynamic equation of the manipulator was considered as an initial point, followed by designing a fuzzy controller for this purpose. To validate the effectiveness of this approach, it was compared to other techniques, such as Fuzzy, Fuzzy-PID, and fuzzy-FOPID controllers, with PID and FOPID controller parameters optimized using clonal selection algorithms. Simulation results reveal that the fuzzy-FOPID variant outperformed other methods under varying load conditions and model uncertainties, using SIMULINK/MATLAB 2014a.

In semi-arid and arid areas, there is little surface and groundwater. Consequently, efforts are being undertaken to protect and collect rainwater as much as possible. When the rainfall is irregular in arid and semi-arid regions, a large portion of it is lost as surface run-off creating a water shortage that puts people at risk. Water collection is a substitute in these circumstances and is crucial. Water harvesting is the process of collecting rainfall and run-off using various storage structures, such as tiny dams, primarily for human, agricultural, and livestock use. For the construction of storage structures to impound and harvest rain and run-off water, forming surface storage reservoirs, four sites with special hydrological and geomorphologic characteristics have been identified and pointed in the drainage map of the studied areas (Tal-Kaif, Zummar, Al-Shor, and Wadi-Almur). A dam model was created using a Global Mapper and Watershed Modeling System program, WMS. Each reservoir's geometrical dimensions and the overall volume of water held behind each site's dams were measured and computed. The four sites' combined storage capacity for water behind the dams might exceed (75×106) m3. Several dam heights were selected in each basin, and the submerged areas for each height were determined to select the optimal height in each basin, i.e., 11.75, 13.9, 9.8, and 12.3 m.

This study presents the effects of including infill panels on the non-linear dynamic response of a hypothetical reinforced concrete frame when subjected to an earthquake. Infill panels are represented by equivalent diagonal struts using three different configurations, i.e., single, double with three different connection locations with the beams, and triple struts. The main goal is to determine the simplest and most appropriate representation of the infill panels by analogous struts. The effect of panel sizes on the non-linear dynamic response of the structure is also presented in this work. The main results showed that including infill panels in the analysis reduced the natural period, roof displacement, and story drift ratio, increasing the roof acceleration and shear forces at the structure base. Utilizing the triple model and the double strut joined at the midspan of the beams showed a good agreement with those using the complete infill model.

The evolving character of the environment makes it challenging to predict water levels in advance. Despite being the most common approach for defining hydrologic processes and implementing physical system changes, the physics-based model has some practical limitations. Multiple studies have shown that machine learning, a data-driven approach to forecast hydrological processes, brings about more reliable data and is more efficient than traditional models. In this study, seven machine learning algorithms were developed to predict a dam water level daily based on the historical data of the dam water level. Multiple input combinations were investigated to improve the model’s sensitivity, and statistical indicators were used to assess the reliability of the developed model. The study of multiple models with multiple input scenarios suggested that the bagged trees model trained with seven days of lagged input provided the highest accuracy. The bagged tree model achieved an RMSE of 0.13953, taking less than 10 seconds to train. Its efficiency and accuracy made this model stand out from the rest of the trained model. With the deployment of this model on the field, the dam water level predictions can be made to help mitigate issues relating to water supply.

Solutions for safer, more durable infrastructure are required in light of increasing traffic and severe weather in Iraq. The most significant road conservation and maintenance challenges are the pavement's low resistance to dynamic loads and short service life. As a result, vast sums of money are spent annually to enhance the road service capacities in Iraq. Thermoplastic electrometric polymers for bitumen modification create long-lasting, cost-effective roadways. This study aims to determine how the mechanical properties of neat asphalt binder change when styrene butadiene styrene (SBS) is added as a modifier. The current research investigates adding three percentages of SBS (3, 5, and 7% of the weight of bitumen). Both neat and polymer-modified bitumen (PMB) were subjected to a series of physical laboratory and Superpave tests, including a dynamic shear rheometer tester (DSR) and a storage stability test. In addition, a chemical analysis test was conducted to identify any change in the neat binder chemical composition due to the addition of SBS polymer. The results indicated that 5% of SBS polymer was the optimum addition percentage to the local asphalt in Iraq. Additionally, it reduced the susceptibility of bitumen to temperature changes and enhanced its characteristics in all laboratory tests. The obtained PMB significantly improved rutting and fatigue factors compared to the neat asphalt binder. Based on the DSR tester and the storage stability test, the ratio of 5% SBS met the requirements of class PG76-10, used in the central and southern governorates of Iraq. Using SBS polymer on the surface course in Iraq reduces road damage due to the scorching summer sun, reduces the likelihood of rutting and fatigue cracking, and works well in hot regions, resulting in roads that last longer, provide comfortable riding, and require less maintenance.

Cooperative None Orthogonal Multiple Access (C-NOMA) is a promising approach for 5G and beyond communication networks. Users will benefit from the full bandwidth of the channel without time constraints. NOMA’s features are incomplete without efficient power allocation that ensures power distribution among users fairly. Integrating power management (allocation) with Cooperative-NOMA (C-NOMA) may improve the system metrics. In addition, a physical layer security (PLS) is added to make the process of sending and receiving safe, and the system works in an integrated manner, preventing any interrupting or eavesdropping inside or outside the network. This paper demonstrates the user and channel performance of C-NOMA with Amplify-and-forward (AF) and Decode-and-forward (DF) approaches. The analysis is performed by varying the power allocation techniques to derive the best system configurations. The simulation results confirmed the analytic findings and showed that the proposed system outperforms orthogonal multiple access (OMA), conventional NOMA, and conventional cooperative NOMA, enhancing the performance metrics in terms of throughput, sum rate, and outage probability. The bit-error-rate (BER) of the far user can be identical to that of the near user if power allocation is properly set. All techniques excelled except for the fixed power allocation, which had the same BER. The Channel capacity and outage probability were also considered. A slight variation in the channel capacity in all the experiments for different numbers of users was found. The generalized power allocation for AF and DF models had the optimum channel capacity close to 14 bps/Hz. Moreover, far users always had a higher outage probability than near users and channels, and generalized power allocation was the highest outage probability technique when the transmit power was close to (4 dB).

This paper introduces the mathematical model of the leader-follower electric vehicle (EV). Consequently, the system was analyzed to obtain stability and performance. Model Predictive Control (MPC) is also proposed to fix the EV system issues. Moreover, two optimization algorithms are applied to optimize the performance of the MPC: electrically charged particle optimization (ECPO) and improved chaotic electromagnetic field optimization (ICEFO). The MPC scheme is based on the Adaptive Cruise Control System (ACCS), applied to two vehicles: the leader and follower. In this context, the simulation results of both optimization methods with the MPC scheme are presented in the result section. Finally, a comparison is made to show the proposed controller’s effectiveness with the improved optimization algorithms. Also, the ACC electric vehicle tracking system was achieved at 98% with the reference input.

This paper presents a direct algorithm for fast real discrete Fourier transform (RDFT) computing, using the discrete Fourier transform (DFT) conjugate symmetric property to reduce redundancies. In RDFT, all the input and output signals were real, which differed from complex DFT. Therefore, the structure of the proposed algorithm showed only real-data operations. The developed algorithm showed the desired properties, such as in-place computation, regularity, simplicity, and arithmetic operations reduction. The RFFT performance was compared with other related transforms, such as the fast Hartley transform (FHT) for the computation in the radix-2 algorithm. It was found that FHT showed the best performance in terms of arithmetic complexity.

This study developed hypotheses based on the geometric analysis of the Badush Dam reservoir to simulate the initial filling and operation of the dam reservoir. A mathematical equation was developed to estimate the daily demand for water behind the dam, and then build an EXCEL program for calculating the input demand, output discharges, and the storage difference for the dam reservoir. Conditions and parameters for continuous/rapid filling and others for gradual filling of the reservoir were arranged in the program. The daily input discharges records, demand, and output discharges produced for the two wet and dry years selected from the records released from Mosul dam to implement the scenarios of rapid and gradual filling of Badush reservoir. The results showed that the reservoir could be filled within 20 or 130 days, according to the continuous (rapid) filling program in the wet or dry years, respectively, and the possibility of filling the reservoir within 133 or 258 days, according to the gradual filling program in the same two wet or dry years, respectively. The operation was more flexible in the dry year than the wet because the wet years may have high daily discharge releases from Mosul Dam, which requires careful monitoring of the Badush reservoir levels. After all, it may rise in a critical period and needs quick intervention by the operator. In rapid filling, it was noted that the daily increase during the days of storage in a wet year was about 1-2 m/day while no more than 1 m/day for the dry year. Regarding the gradual filling, the daily increase during the days of storage in the wet year varied between 1-3 m/day on some days that do not coincide with the peak flood wave. In the second stage, which lasted only two days, the level rose between 3-4 m/day. The third stage, which lasted only one day and coincided with the peak flood, was accompanied by a sharper increase in the level, reaching 7 m/day. The daily level increased from a few centimeters to 2 m/day through the gradual filling in the dry year.

Electric discharge machining (EDM) is regarded as one of the most energy-efficient manufacturing processes for exceptionally accurate processing of any electrically conductive material, regardless of mechanical properties. EDM is a non-contact process utilized in various industries, including aerospace, industrial, instruments, molds, dies, and medical tools; also, it is beneficial for hard materials with simple or proficient geometries and shapes. Although EDM is for machining "difficult to machine" metals, such as those used in the mold and die industries, metal properties indicate potential capability in the domain of surface modification due to the electrical spark between the tool and the work material. This paper investigates the machining of Alloy steel X210 by using the most affecting parameters and how electrode angles contribute to responses, as MRR, Electrode wear ratio, and surface finish, which the manufacturing industry uses to make die tools, molds, automotive parts, and other products. Electrodes with angles of 0o and 90o are used to machine workpieces using WEDM (dk7740). Electrode Angle, peak discharge current, pulse-on time, and pulse-off time were controllable parameters in this study. While all other criteria are constant, variables have been studied. The effects of the four aspects on the four variables were statistically analyzed using ANOVA by MINITAB. Regression models for the responses were developed. Regression mathematical models have been developed for Alloy steel X210 workpieces to increase productivity and industry results.

The Internet of Things (IoT) technology has recently emerged as a potential global communication medium that efficiently facilitates human-to-human, human-to-machine, and machine-to-machine communications. Most importantly, unlike the traditional Internet, it supports machine-to-machine communication without human intervention. However, billions of devices connected to the IoT environment are mostly wireless, small, hand-held, and resourced-constrained devices with limited storage capacities. Such devices are highly prone to external attacks. These days, cybercriminals often attempt to launch attacks on these devices, which imposes the major challenge of efficiently implementing communications across the IoT environment. In this paper, the issue of cyber-attacks in the IoT environment is addressed. An end-to-end encryption scheme was proposed to protect IoT devices from cyber-attacks.

The idea proposed in this study can be used in remote areas to lift the water spontaneously instead of using electrical pumps. This research aims to lift the underground water to a high altitude by designing a passive system that simulates the rising water in tall plants due to capillary action and evaporation. The study assumed a set of micro-tubes to lift the underground water to a tank. The flow rate due to capillary rise and evaporation were analytically determined by mathematical models based on energy equations in fluid mechanics calculated using MATLAB software. The study results have shown that a ‎system consisting of 2-10 billion micro-tubes can supply between 16-65 kg of water daily to a tank, depending on the ‎environmental conditions‎. It was found that a set of tubes with a 20 μm diameter was a suitable choice to raise the water to 7.5 m, where 0.8 m rising was due to the capillary action, whereas the rest was due to the evaporation process suction head.