Tikrit Journal of Engineering Sciences

For the first time, dual-performance perfection technologies were used to kinematically operate sophisticated robots. In this study, the trajectory development of a robot arm is optimized using a dual-performance perfection technique. The proposed approach alters the robot arm\'s Kinematics by creating virtual points even if the robotic system is not redundant to make it kinematically suitable for biomedical applications. In the suggested method, an appropriate objective function is chosen to raise one or maybe more performance measures while lowering one or more kinematic characteristics of a robot arm. The robot arm\'s end effector is set in place at the crucial locations, and the dual performance precision algorithm changes the joints and virtual points due to the robot arm\'s self-motion. As a result, the ideal values for the virtual points are established, and the robot arm\'s design is changed. Accordingly, this method\'s ability to visualize modifications made to the processor\'s design during the optimization problem is one of its benefits. The active robotic arm is used as a case study in this article. The task is defined as choosing the best path based on the input target\'s position and direction and is used in X-ray robot systems. The outcomes demonstrate the viability of the suggested approach and can serve as a useful prototype for an intelligent X-ray robot.

In electrodialysis, an ion exchange membrane removes unwanted ions from wastewater and toxic metal ions from effluents. Montmorillonite-based modified \"polyethersulfone membranes\" have been studied as a potential small-scale electrodialysis approach for removing ions from wastewater. The study featured several steps, including solid polymerization, electrolyte balance, and removal of each component from the water. The study used three distinct “cation-exchange membranes (CEM)\" types. The selected water body was diluted 100 times before being added to the electrodialysis cell in amounts of the center, cathodic, and anodic chambers, each containing 55, 30, and 40 mL. The initial pH for the real solutions of the water body was 7.16 at 25°C. Compared to \"Sulfonated poly arylene ether sulfone (S-PESOS)\" (23.23%) and Nafion® (35.34%), \"hexamethylenediamine (HEXCl)\" stands out as the only cross-linked material with significantly high-water content. When the membrane water content is too high, the membrane may lose its mechanical strength and cannot provide enough ionic conductivity. The semi-empirical model\'s parameters were estimated to simulate the elimination of Na+, K+, Ca2+, and Mg2+ by three membranes. HEXCl and S-PESOS were electrodialyzed and used to treat the serial dilution from the water with cationics. The removal rate gradually rose after the electrodialysis started.

Image deblurring is a common issue in low-level computer vision aiming to restore a clear image from a blurred input image. Deep learning innovations have significantly advanced the solution to this issue, and numerous deblurring networks have been presented to recover high-quality images. This study aims to investigate the impact of Blind deconvolution and Non-Blind Deconvolution (Weiner Filter, Regularized Filter, and lucky Richardson) deblurring techniques and blind deconvolution to retrieve the original image from the blurring and the noisy images. Point Spread Function (PSF) is required to perform the deconvolution process. MATLAB program is utilized in this study as a suitable tool for image processing. Peak to Signal Ratio (PSNR) and structural index similarity (SSIM) are the major parameters used to examine image quality. The results showed that the Regularized Filter was an effective technique to deblur the blurry image, and it achieved the largest PSNR and best SSIM with the prior information about the PSF for different degrees of blurring angle. These four deblurring techniques were unsuccessful in restoring the original image from the image with Gaussian noise.

The presence of hazardous metals, such as nickel and copper, has been identified in the effluents of the textile industries. Due to such hazardous components, this waste water exhibits a significant chemical oxygen demand (COD). Various methods are used to reduce the COD presence in the effluents. This investigation employs hydrodynamic cavitation, to decrease COD levels potentially. This reduction is achieved by implementing different orifice plate designs, including 3-star pattern, 3-circular hole pattern, 5-star pattern, and 5-circular hole pattern, as part of an innovative strategy. According to current investigations, implementing the 5-circular hole layout significantly reduced of COD by 49.14%. In contrast, using the 5-star design yielded a low drop of 34.15% COD. These experimental findings indicated that the most effective orifice plate for removing COD from textile wastewater was a circular design with 5- holes.

For performing an assessment of the volume estimation accuracy using Digital Elevation Models (DEMs) generated by Unmanned Aerial Vehicles (UAVs), an evaluation of suitability has been made. The study was operated at Tikrit University, on a man-made topographic depression in the form of fishponds. The generated DEM by using the images of the UAV followed by accuracy assessment using Ground Control Points (GCPs), the points distributed evenly throughout the pond. The results showed that the Root Mean Square Error (RMSE) calculated for the DEM at the optimum flight plane ranged between 0.14 to 0.45. Comparing the pond's predicted volume utilizing UAV DEMs to the ground truth volume obtained using GNSS RTK surveying, it was discovered that the UAV DEM calculation was 97% accurate. The study came to the conclusion that the UAV Structure from Motion (SFM) method and the generated DEMs are appropriate for precisely surveying the volumes utilizing the appropriate range of flying parameters based on prior knowledge.

The modular multilevel converters (MMC) utilization has brought about a transformative impact on high voltage direct current (HVDC) transmission relying on voltage-sourced converters (VSC). However, their application in medium-voltage (MV) variable-speed motor drives has not achieved broad acceptance due to the substantial voltage fluctuation in the capacitor, especially at lower frequencies. The present study introduces a hybrid MMC (HMMC) aimed at markedly limiting capacitor voltage fluctuations, particularly during low motor speeds. Vector control was used to achieve the required motor speed. The proposed HMMC validity was confirmed through the MATLAB/ SIMULINK environment. The results were compared with conventional MMC from the standpoint of the capacitor voltage fluctuation at low frequencies.

In this study, a program was built to simulate the sudden and complete collapse of the Mosul and Badush Dams behavior towards this collapse and predict the level at which the water will balance in the two dams after the collapse, compared to different levels at the Mosul Dam before the collapse. Two mathematical models were built as inputs to this program. The first predicted the water level in the Mosul Dam reservoir in terms of its storage volume before the collapse, and the second predicted the water level in the Badush reservoir after the collapse, according to the level in the Mosul reservoir before the collapse. For each collapse scenario, the program was organized according to sequential steps summarized assuming the water level in the Badush Dam reservoir when the level stabilizes, and from it determining the water volume in Badush reservoir based on the geometric analysis of the reservoir, then the volume of water transferred from Mosul reservoir to Badush reservoir, and thus the volume of water inside Mosul reservoir before the collapse. From the first mathematical model, the level of the Mosul Dam reservoir was determined before the collapse. The second mathematical model determined the level of the Badush Dam reservoir after the collapse. The results showed that the program has high flexibility in predicting what will happen in the Badush Dam reservoir after the collapse based on the water level in the Mosul Dam reservoir before it collapses and that the limits of the program's work extend from the minimum to the maximum level in Mosul Dam at which the failure can occur. Also, the storage volume in Mosul Dam will be distributed to the two reservoirs after the failure until the level stabilizes. Badush Dam, at a level of 330.4 m (a.s.l), can expand the maximum flood wave resulting from the total and sudden collapse of Mosul Dam at its maximum level of 333 m (a.s.l).

Concrete corbels are short cantilevers subjected to monotonic and repeated loads. Repeated loads generally negatively affect the concrete structural members' strength as they decrease the resistance to external loads. To increase these loads, strengthening with carbon fiber reinforced polymer (CFRP) strips as an externally bounded technique is used. This paper studies the behavior and strength of strengthened corbels subjected to monotonic and repeated (constant and incremental) loads. The experimental program included the casting and testing of twelve double-concrete corbels. All specimens have been kept constant for corbel dimensions and main and secondary reinforcement. Nine were strengthened with CFRP strips using different patterns, while the others were left un-strengthened as control corbels. The results showed that both repeated loads' types, i.e., constant and incremental, affected the ultimate load capacity of corbels. Compared to monotonic loading, a reduction occurred in ultimate load and ultimate deflection for corbels subjected to five repeated loading cycles. For corbels strengthened by externally bounded CFRP strips under any applied loads, the ultimate load significantly increased, while the ultimate deflection decreased compared to un-strengthened at the same applied load. All corbels failed by de-bonding the CFRP strips.

RFID plays a vital role in data communication in multidimensional WSNs as it collects vast amounts of redundant data. The physical phenomena constitute the correlated observations in the space domain and generate spatial correlation. Periodic observations of sensor nodes result in a temporal correlation in the data. Reducing these spatio-temporal correlations in RFID surveillance data is necessary for the smooth functioning of the network. This paper proposes a Voronoi diagram-based spatio-temporal data redundancy elimination approach for RFID systems having multiple readers so only one reader will read every RFID tag depending on the distance between the tag and the center of the Minimum Enclosing Circle of the Voronoi cell to which the reader belongs. This approach eliminates spatial redundancy in the gathered data. Reading the RFID tags at regular time intervals larger than a chosen threshold value minimized temporal redundancy. In contrast to existing methods, the proposed technique is free from any false positive and false negative errors, with no loss of data and every tag being read by only one reader. Simulation of the proposed approach also established its superiority to the existing techniques in terms of these performance parameters.

The Smartflower, an innovative compact energy-generation system inspired by sunflowers, stands out in energy innovation. Unlike traditional photovoltaic (PV) panels, it integrates foldable solar cells within a foundational structure for solar tracking aligned with the sun's path. The present paper focuses on designing, fabricating, and analyzing a proposed Smartflower-PV panel solar system. The study aims to comprehensively evaluate the performance of the proposed PV panel under different atmospheric conditions. The significant impact of insolation and temperature on the panel's efficiency was revealed by comparing empirical results from the PV sunflower panel with analytical calculations using MATLAB (m. file code). Enhanced solar radiation improved the system’s performance and efficiency, resulting in higher power output. Analytical insights showed a direct correlation between a 104% increase in solar radiation and parallel increases of 115% in peak power production and 100% in output current. Conversely, higher temperatures reduced power output, with a 400% temperature rise causing an 11.11% power reduction. Empirical observations align with analytical analyses under equivalent conditions, validating the model’s accuracy. This study serves as a catalyst and guide for completing and advancing the Smartflower system's manufacturing, including control, tracking, and the entire energy-generation framework.

The modern power grid faces rapid growth in load demand due to industrialization, leading to an unregulated environment and increasing adoption of renewable energy sources, which presents technical challenges, particularly in terms of stability. Hydrogen conversion technology revolutionizes clean electricity storage with renewable energy, and solar hydrogen is now available in autonomous solar systems. The efficiency of solar photovoltaic systems is closely related to using digital electronic maximum peak power tracking (MPPT) technology. The Internet of Things (IoT) is crucial for performance monitoring and real-time control of PV systems, enhancing the understanding of real-time operating parameters. IoT and wireless sensor networks for distributed solar energy devices and joint building design are essential for developing the photovoltaic construction industry. In this paper, the monitoring system that has been proposed offers a potentially effective solution for the intelligent remote and real-time monitoring of solar photovoltaic (PV) systems. It demonstrated a high level of accuracy, reaching 98.49%, and can transmit graphical representations to a smartphone application within a time frame of 52.34 seconds. Consequently, the battery's longevity was extended, energy consumption was diminished, and the quality of service (QoS) for real-time applications inside the Internet of Things (IoT) was enhanced.

Multilevel inverters (MLIs) have become more popular for medium-voltage and high-power applications. The cascaded H-bridge multilevel inverter (CHBMLI) is one of the three most popular topologies of MLIs. It was more reliable due to its fewer components per level. The number of possible output voltage levels is more than twice the number of DC sources, the most suitable topology for integration with renewable energy sources, easy to design, and has good performance with modularity. The main disadvantage of CHBMLI is the need for separate DC sources for each H-bridge. However, this can be considered as an advantage to be employed in renewable energy applications. This paper provides a review of CHBMLI topologies and pulse width modulation (PWM) techniques, including fundamental and high switching frequency techniques, such as selective harmonic elimination (SHE), space vector modulation (SVM), nearest level modulation (NLM), and Carrier-Based PWM.

The present study examined and simulated the coding or no coding performance for different configurations of multi-input, multioutput underwater wireless optical communication systems. MIMO diversity and channel coding were used to reduce the power transmitter, assuming lognormal distribution random for weak ocean turbulence. The simulation tested for a link range of 30 m in low ocean turbulence and 500 Mbps on–off-keying was also presented using Monte-Carlo. The results showed improvement in power transmitted (gain) for 2x5 compared to Uncoded SISO, which was about 33.60db using the concatenated code. So that the underwater wireless optical communications (UWOC) even now will also be significantly impacted by the Internet of Underwater Things (IoUT) and ultimate mobile technologies five generation communication systems because of their extraordinarily high demand for data safety, bit rate, energy consumption, so it is used in combined data transfer between underwater communication devices. The UWOC system based on coded MIMO may successfully be used in IoUT due to its high robustness and power qualification.

Iraq has a semiarid and desert climate. Also, it is predicted to be more susceptible to global warming effects. In the present study, daily climatic data from the past and projected future of the Upper Zab Basin, located in northern Iraq and considered an example of arid and semiarid climate conditions, were simulated using LARS-WG 6.0, i.e., a stochastic weather generator. The model also estimated daily rainfall and temperature. Using the RCP4.5 and RCP8.5 main emission scenarios, the future climate throughout the current century was estimated utilizing the MIROC5, CanESM2, HadGEM2-ES, ESM1-M, and CSIRO-Mk3.6.0 general circulation models (GCMs). This estimation was performed considering the significant uncertainty of future climate estimates. The model, constructed using thirty years' worth of historical data, was validated using climate data from the Upper Zab Basin in northern Iraq (1990–2021). According to the data, the average monthly maximum temperature will decline by 2.15–6.20 °C under RCP4.5 and 1.81–6.10 °C under RCP8.5 by the end of the twenty-first era for the corresponding upstream and downstream sub-basins. Precipitation projections from all GCMs showed varying patterns. Given that some models, like CanESM2, expected a rise in precipitation, while others, like MIROC5, forecasted a future with no change in precipitation or a falling trend, which illustrates the significant level of uncertainty in precipitation forecast when only one model was utilized. Also, the downstream sub-basin suffered the most during the 1999–2000 and 2007–2008 droughts, with average RDIst values of -1.97 and -1.64, respectively. However, the upstream sub-basin had moderate to severe droughts in 1999–2000 and 2007–2008, with average RDIst values of -0.81 and -1.84, respectively. The water available in the research location will be significantly impacted by variations in rainfall and temperature.

Since Makhol dam is planned to be constructed on Tigris River to the north of Baiji discharge measurement station, it is essential to study the nature of inflow into this reservoir. The information concerning this inflow is of great help in operating and management of the prospective reservoir. From our point of view, it is necessary to know how these inflows are distributed and contributed to Tigris from different upstream sources. Disaggregation flow models are stochastic generation techniques, that used to divided data into lower time scales from higher time scales using parametric approaches with two main categories: spatial and temporal. In the streamflow disaggregation model, historical data statistics (mean, skewness, standard deviation, maximum, and minimum) can be preserved while distributing single-site values to several sites in space and time. In this study, the aggregated streamflows data at a key station will be disaggregated into a corresponding series of discharges at sub-stations that are statistically similar to those observed by applying Stochastic Analysis Modeling and Simulation (SAMS 2010) software. To investigate the appropriate the disaggregation method for modeling monthly flow data, we used the annual and monthly data flow of five gauging stations in the Tigres River in Iraq (Mosul Dam station on Tigris river, Asmawah on AlKhazir river, Eski Kalak on Upper Zab, Dibs Dam on Lower Zab, and Baiji station on Tigris river) for the duration 2000–2020. The application approach's statistical outcomes were contrasted with their historical counterparts and the results showed that most years and months at all stations were in good agreement with the historical data. Therefore, we argue that this method have ability to be used when making decisions about water management strategies in these regions which is essential for water resource managers and decision makers.

Dyes are used in the textile, paper, plastics, leather, foodstuff, and artificial fiber industries. Congo red dye (CR) is one of the dyes found in industrial wastewater. The present study investigates the Congo red dye removal from aqueous solutions using low-cost adsorbents that are eco-friendly and highly efficient, such as activated carbon prepared from Buckthorn fruit (BT) under various experimental conditions, as an ideal alternative to the current expensive methods for removing dyes from aqueous solutions. X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), and Fourier-transformed infrared (FTIR) analyses were used for the fabricated-activated carbon characterization. Based on batch system experiments, various variables affecting the adsorption process were studied, including the solution’s pH, adsorbent dose, contact time, initial dye concentration, and mixing speed. The results showed that the highest dye removal efficiency was 63% at pH = 5, the contact time was 80 minutes, the dose of adsorbent was 3 g/l, and the mixing speed was 150 rpm. The data from the experiments were analyzed using the Langmuir and Freundlich model and showed a high agreement with the Langmuir model (R2 = 0.989). When studying the adsorption kinetics, the results agreed with the Pseudo-second order, where the values of K2 and R2 were 0.083g/mg. min and 0.992, respectively. The adsorption was endothermic and spontaneous, as shown by the thermodynamic parameters study at 25, 35, and 45 °C, where the ∆H was 13.709 kJ/mol and ∆G values were negative values. The study also showed the possibility of using Buckthorn fruit as a low-cost adsorbent in CR removal.

The hardware design, implementation, and digital control method for three-phase AC induction motors based on Field-Oriented Control is discussed in this work Solar-powered water pumping systems have become an practical option for remote irrigation and water supply as renewable energy sources obtain importance. This research enhances such systems performance and dependability by employing a Voltage Source Inverter. In order to optimize the energy transfer to the water pump, the recommended approach uses the Voltage Source Inverter capabilities to transform the variable DC output of the solar panels into a controlled AC supply. The research looks at the choice of power components, control algorithms, and modulation strategies while designing the Voltage Source Inverter. The most suitable modulation strategy is determined after an in-depth review of several different approaches to ensure greater pump performance. This research clarifies on how solar energy conversion and pump control work together to provide sustainable water management in off-grid areas. The research paper "Design and implementation of VSI for Solar Water Pump Control" demonstrates how solar water pumping systems can be optimized using power electronics and control. The project addresses efficiency difficulties and operational differences to create efficient and reliable solar-powered water delivery systems, which support environmental sustainability and rural development. Based on the power of the PV panel, the P&O MPPT method calculates the submersible pump speed. The sensorless speed control method eliminates the requirement for location or speed sensors. The Black Electro-Motives Force calculates speed by estimating the flux angle in the absence of mechanical speed sensors. This method reduces costs and simplifies the system simply by eliminating the requirement for expensive and complicated speed sensors. In order to determine steady-state and dynamic performance in varying insolation conditions, a prototype 5.5 KW inverter was constructed. In conclusion up, the research provided a thorough summary of the hardware and control aspects required for Field-Oriented Control in irrigation systems. The practical outcomes of this study have the potential to spur advancements in irrigation technology and the incorporation of renewable energy, resulting in substantial gains for agricultural productivity and environmental conservation.

Due to the rapid growth of the construction industry in Iraq, this study aims to identify and diagnose the reasons behind the poor performance of ready-mixed concrete production plants in Baghdad. This aim was achieved by analyzing the standards affecting the plants’ performance and identifying the cause of the deviation from their required performance using the root cause analysis technique through innovative tools and techniques, such as Pareto charts and the why technique. The study analyzed 35 reasons, divided into seven main groups: work breakdown structure, skills, shared values, systems, Administrative Styles, strategy, and staff. The results showed 23 out of 35 reasons with significant importance on the plants’ performance. The Pareto analysis revealed that nine causes out of 35 reasons were responsible for 80% of the poor plants’ performance. These included the lack of work breakdown structure in enhancing the functional performance of work teams and maximizing the utilization of their skills, as well as the insufficient number of work teams, two root causes of the work breakdown structure group. Another root cause from the skills group was the necessary skills lack among most work teams and the training programs and workshops absence for work teams. The study also found that the plant management's lack of focus on competition, excellence, and innovation was a root cause of the strategy group. In addition, the advanced techniques used for producing high-quality concrete mixes and the absence of a fair and accurate incentive and reward system were the root causes of the systems group. Furthermore, the management's failure to adopt control methods in all field and administrative work stages was a root cause of the management systems group, and the work teams' failure to adopt the knowledge-sharing approach was a root cause of the work teams' group. Using the "why" technique, it was found that the root cause was the absence of an objective, fair, and accurate incentive system in ready-mixed concrete production plants.

The study aims to reduce heat transfer in a building's conditioned space due to high environmental temperatures in the summer. The heat transfer through the building's external walls increases the need for electrical energy. This study developed four models to reduce heat transfer by covering the exterior wall of the building with perforated concrete blocks with holes, whose diameters varied within the range of 6–10 mm, distributed in three rows of variable hole diameter, each row containing three holes of equal diameter: Model A1 (the diameter of the three holes in the first row was 6 mm, and the diameter of the three holes in the second row was 8 mm, while the diameter of the three holes in the third row was 10 mm). Model A2: The hole arrangement with the sequence 10, 8, and 6 mm. Model B1: The hole arrangement was with the sequence 6, 10, and 8 mm. Model B2: The hole arrangement was with the sequence 8, 10, and 6 mm. The study examined the air gap between the building's covering blocks and the original wall. A thermal test room was built with an air conditioner and a cumulative electric energy meter to measure energy consumption. Perforated block models covered the test room's wall. Also, a numerical model was prepared using the ANSYS-Fluent package v. 16.2. The experimental and numerical results were consistent. Model B1 achieved higher electrical seasonal consumption than the conventional model, about 98.5 kilowatt-hours. While the other four models recorded low energy consumption, i.e., model A1 consumed 87.5 kilowatt-hours, with a reduction of 11.2%; model A2 consumed 83.9 kilowatt-hours, with a reduction of 15%; model B2 consumed 80 kilowatt-hours, with a reduction of 19%; and model B1 consumed 78 kilowatt-hours, with a reduction of 21%.

This work investigates the kinetics of catalytic dry reforming of methane (CDRM) to produce hydrogen gas using nickel-based catalysts. A new catalyst was prepared, Ni-ZrO2@MCM-41 (MCMZ) and used in the CDRM reaction. The textural, physical, and morphological scans are used to characterize the prepared catalyst. The performance of the newly prepared catalyst in terms of temperature effects and long-term stability is assessed. The reaction activation energy is studied as well. The outcomes of this study revealed that the MCMZ provided the highest conversion values for CH4 and CO2, with 89 and 91%, respectively. The optimum reaction temperature to achieve the highest syngas conversion was 800 °C. In addition, two new models that present CH4 and CO2 conversions for MCMZ as a function of reaction time to predict the rate of catalyst activity were built with very high accuracy. It was found that the activation energy was within the expected limits. Finally, the constants and reaction rate were determined. To conclude, this research creates a new catalyst with high performance to enhance hydrogen gas production from methane with carbon dioxide that contributes significantly to the field of yielding alternative energy sources.

Biodiesel production provides a diversified and renewable energy source offering lower greenhouse gas emissions than traditional diesel. It also offers economic benefits by reducing dependence on imported fossil fuels. Castor oil transesterification is an essential process in the creation of biodiesel. In this experimental study, castor oil transesterified using methanol, and potassium hydroxide was the catalyst. The effects of various reaction parameters, including temperature, the molar ratio of methanol to oil, and catalyst concentration, on the biodiesel yield were studied and optimized by the conventional method followed by the statistically based Box-Behnken design method. The maximum yield was reached at a temperature of 65°C, a molar ratio of 12:1 methanol to oil, and a catalyst concentration of 1.5% by weight. The yield of biodiesel under these conditions was 93%. The optimized results of experiments showed increases in yield to 93.36% at 65°C temperature, 14.12:1 a molar ratio methanol to oil, and a 1.12% by weight catalyst concentration; hence, the optimal temperature was the highest achieved value. The fatty acid methyl ester composition analysis revealed that the major constituents of the biodiesel were ricinoleic acid methyl ester, linoleic acid methyl ester, and oleic acid methyl ester. The findings of this research highlight the significance of selecting the appropriate reaction conditions to maximize biodiesel yield. Also, it was found that castor oil had the potential to be an essential feedstock for biodiesel production.

The growing concern about global warming and climate has raised the research field dedicated to finding solutions. One area that has received considerable attention is the exponential increase of carbon dioxide emissions from the atmosphere from the petroleum and gas industries. So, to solve this problem, researchers investigated new ways to collect CO2 from the air depending on the fact that CO2 is soluble in water because using aqueous amine absorbents to collect CO2 has a lot of drawbacks, such as the need for tremendous energy to recycle the solvent and high operational costs. In this study, a specific type of deep eutectic solvent (DES), namely Choline chloride + monoethanolamine (ChCl-MEA), was used as a promising solvent in the CO2 capture process. Solubility measurements were conducted at 1:6 molar ratios. The amines chosen are typical of basic amines. Experiment absorption data were investigated at various parameters, including a concentration range of 0–3 mol/L, temperatures ranging from 25 to 45 °C, and absorption durations ranging from 60 to 120 minutes, to get the best conditions for high-loading CO2 uptake. The study found that amine-based DESs had a significantly greater absorption capacity than monoethanolamine-based and conventional DESs. The study examined what happened when water was added to a deep eutectic solvent made of choline chloride and monoethanolamine (ChCl-MEA DES). The most effective way to absorb CO2 was physical absorption, which can hold 276.13 mol CO2 per gram of DES at 1 bar and 29.025 °C when mixed with water. The deep eutectic was mixed with water to increase the absorption efficiency. 10 ml of aqueous solution (DESs + water) was taken. The combination of DES and water significantly increased CO2's low solubility. The modified Design-Expert model satisfactorily represents the experimental solubility of CO2 in the solvent. The average percent differences between experimental and projected values were 10.7% and 6.8% for binary and ternary systems, respectively. The optimal conditions for maximum absorption rate were 29.025°C, 2.233 mol/L, and 101 minutes, with an absorption ratio of 0.0734 mol/kg.min and efficiency of absorption of 85.3% for solution DESs and water.

Non-Orthogonal Multiple Access (NOMA) is a cutting-edge technology that permits several users to use the same frequency resources and transfer data at once. Visible light communication also known as VLC, is an innovative technology that offers access to an unoccupied spectrum, enables fast data transmission speeds, thereby making it a complementary addition to current radio frequency technology. Although VLC has its advantages, it also comes with some downsides. One major issue is the modulation bandwidth of LEDs, which can be quite challenging when creating high speed VLC systems. Non-orthogonal multiple access (NOMA), particularly power-domain NOMA (PD-NOMA), has become a viable multiple access approach, ensuring sufficient bandwidth allocation for VLC systems. This study delves into multiple access techniques in VLC systems, in particular NOMA, and discusses its fundamental principles, key ideas and practical implementations like vehicular communication. It also addresses the associated hurdles, such as ensuring equitable distribution of optical power among users, leveraging MIMO technology, and grappling with LED nonlinearity issues. In summary, we underscore the significance of utilizing NOMA-VLC technology to enhance wireless communication systems and optimize spectral efficiency.

Solar energy is a key player among other renewable energies that reduce greenhouse gases and replace conventional fuel, i.e., to solve global warming and fossil fuel descending issues. However, the thermal solar systems’ performance should be enhanced to cope with intermittent solar radiation. Metal foam can be used as an enhancer in solar collectors’ receivers. However, metal foams are associated with pressure drop. To benefit from the metal foam as a thermal enhancer and overcome the pressure drop issue, the present study numerically and experimentally investigates a novel Compound Parabolic Solar Collector (CPC) receiver with innovative uneven metal foam inserts of varying thickness. Two pores per inch (PPI) Cu-foam inserts, PPI10 and PPI20, were tested. These inserts were strategically placed at three different positions along the receiver, with thicknesses of 3 cm, 2 cm, and 1 cm starting from the inlet side. In the experimental part, three tubular receivers were tested, empty, i.e., without metal foam, inserted with Cu-foam of PPI10, and inserted with Cu-foam of PPI20. The experiments were conducted from 09:00 AM to 04:00 PM. The investigation involved water volume flow rates from 0.2 to 0.6 l/min. The numerical part included solving the governing equations, i.e., mass, momentum, and energy conservation, simulating conditions similar to the experiments. The Brinckman model described the fluid flow through the metal foam. The thermal performance of the CPC system was evaluated using the Nusselt number (Nu), thermal efficiency, water bulk temperature, and water outlet-inlet temperature difference. Inserting Cu-foam of PPI20 resulted in the hourly maximum Nu and thermal efficiency compared to the empty and PPI10 cases. Experimentally, the hourly maximum Nu was 8.9, 8.4, and 7.9 for PPI20, PPI10, and empty receivers, respectively, at 0.6 l/min. The average thermal efficiency was 88.3, 85, and 81.9 for PPI20, PPI10, and empty receivers, respectively, at 0.6 l/min. As for the outlet-inlet water temperature difference, the highest values were at 0.2 l/min. Again, PPI20 recorded the best results, i.e., 23.3 K, 21.5 K, and 20.2 K for PPI20, PPI10, and empty cases, respectively.

The owner of construction projects often faces difficulty choosing the appropriate project delivery system. The construction project’s owner must choose a suitable project delivery system throughout the project's early decision-making stages. This choice greatly impacts the success of the project. This paper aims to construct a method for project delivery decisions. This method can provide a reference for the owner to select the proper project delivery system. This research described the factors affecting the decision about the project delivery method through a literature review. These factors were categorized into eight groups: scope, time, quality, cost, risk and relationships, owner organization, project characteristics, and external environmental factors. Then, a combined methodology of Stepwise Weight Assessment Ratio Analysis (SWARA) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are proposed for project delivery system selection. The SWARA is used to determine the factors’ weights. The TOPSIS technique determines the rank of the alternatives proposed for the delivery system in the various categories. The results showed the most significant factors related to the cost with a weight of 0.335, and the design-build is the closest to the ideal solution and ranked first among the other suggested project delivery systems with a relative closeness of 0.829. This paper stipulates the basis for such a process of decision-making.