Al-Qadisiyah Journal for Engineering Sciences

This work seeks to use both traditional control algorithms and advanced optimization algorithms to enhance the performance of a DC-DC converter. The chosen algorithm was Proportional-Integral-Derivative (PID) based on gray wolf optimization (GWO). The PID controller is known for its ease of control and wide range of industrial applications. This type of controller has been used successfully in many types of systems, such as power electronics, automation systems, robotics, etc., due to its ability to effectively optimize the system's parameters with minimal effort from the user. To test this new technique on a DC-DC converter, different simulations were conducted using a MATLAB environment where various parameters that can simulate various uses for the DC-DC converter within electrical systems were set. After conducting these tests, it was found that PID based on GWO controller had good performance (rise time 0.0004 sec, settling time 0.0001sec) when compared with other traditional controllers (increase time 0.00416 sec, settling time 0.000323sec), reliability, efficiency, higher accuracy, low cost, etc. As expected, GWO showed better results than conventional methods like PID or PI controllers due to the fact that it’s an evolutionary approach that allows more flexibility during the configuration process.

¬The widespread of a Wireless Local Area Network (WLAN) access network in residential areas provides low-cost and high-speed access to the Third-Generation Partnership Project (3GPP) services for end users. This has virtually made WLAN to be a complementary access network to Universal Mobile Telecommunications System (UMTS). WLAN and UMTS's interoperability is made possible using a mobility management mechanism in IP Multimedia Subsystems (IMS) architecture. Current problems in mobility management mechanisms are found in device mobility, such as mobile phones. Such problems affect several layers and disrupt services. In this paper, IMS mobility management mechanisms with G1 mobile phone as an IMS client testbed are implemented, and its impact on the Quality of Experience (QoE) during end-to-end VoIP call session and its conformity to the 3GPP requirements of seamless service continuity is evaluated. The QoE driven mobility management mechanism is then proposed and evaluated to improve the QoE and meet the 3GPP requirements of seamless service continuity during the handover between UMTS and WLAN access networks. Preliminary results show that there is an improvement in QoE, and the requirements of 3GPP service continuity were met. The proposed Quality of Service (QoS) driven mobility management mechanism will help develop dual-mode mobile handsets with QoE adaptability.

The mechanical design of metals must deal with structures collapsing due to cracks occurring in the material. This study focused on the edge crack at non-proportional cycle loading because it propagates quickly. This research attempted to determine two mathematical models that could predict the crack propagation rate for thin samples of aluminum alloy types 6061 and 5052 under constant tensile stresses and cyclic shear stress applied within the elastic limits of the material using Griffith energy of dynamic fracture. This was performed to evaluate if these models can predict crack growth rates and compare them with the numerical results of a computer system in the ANSYS program R1 2021. The direction of the crack path was calculated and compared with the analytical program. The results of the two mathematical models in predicting the dynamic growth rate in the studied alloys gave low error rates to the numerical solution.

This research aims to find ways to use different mixtures instead of R134a refrigerants that are more efficient and better for the environment. The Kyoto Protocol states that hydrofluorocarbon refrigerants must be replaced due to their high Global Warming Potential values, contributing to environmental damage. The two mixtures tested in this research were both types of refrigerants with different performances, temperatures, and pressures. The first mixture comprises R 134a and R1234yf (10:90% by weight), while the second mixture is R600a and R290 (60:40% by weight). The study revealed that the coefficient of performance of the first and second mixture is higher than R134a by 20.44% and 16%, respectively. Also, the power input of R134a is higher than that of the first mixture by 15.3%, while the second mixture is lower than R134a by 25.8%.

In this research, an assessment was conducted for several materials to examine their efficiency for sorption phosphate and their potential use as filter media. This work focuses on seeking materials that can achieve high, rapid, and robust phosphate retention. To assess the phosphate removal efficiency, batch-mode testing was conducted. The capability of the selected materials for effectively removal the phosphate is largely influenced by their inherent properties. Therefore, this research determines the effectiveness of the material by examining its physical and chemical characteristics. The selection method for these materials was guided by the understanding that the sorbents that have the most effective behavior for phosphate tend to contain easily soluble Ca/Mg compounds or Fe/Al hydroxides. The findings of the batch experiments demonstrated that material such as Bio ash (Bio-A) exhibited superior phosphate removal performance throughout the entire duration of the experiments. In contrast, materials calcium carbonate (C-C) and conventional silica (C-S) displayed relatively poor removal performance compared to Bio-A.

The identity of Islamic cities is distinctly manifested through their congregational mosques, primarily characterised by their continuous and stable function, epitomised by the five daily congregational prayers. The performance of a mosque is intricately linked to a set of religious, organisational, structural, and economic determinants, and it is closely tied to the functional and architectural attributes of its elements and spaces. The historic congregational mosques in the Islamic world have predominantly adhered to the architectural model of the Prophet's Mosque, characterised by its rectangular form. In modern mosques, various factors, such as technological advancements and cultural and scientific influences, have led to architectural trends and stylistic innovations. These innovations have aimed to enhance the efficiency and performance of congregational mosques, one of which is the octagonal form. The research problem centered on the utilisation of the octagonal shape and its adaptability in the context of the congregational mosques in the city of Mosul and its suitability for optimal mosque functioning. The research sought to elucidate the appropriateness of employing the octagonal form in congregational mosques by analysing samples with octagonal layouts in Mosul to investigate the extent to which this form influenced the characteristics of the mosque. The research concluded that all octagonal layouts had undergone modifications and expansions to rectify the unsuitable layout, indicating that the octagonal form is foreign to the traditional mosque typology. Furthermore, it is subject to additional alterations to accommodate the functional and architectural requirements of the congregational mosque.

Plastic has emerged in many modern industries, and petroleum is an essential source for the manufacture of many materials of importance in our contemporary life, such as plastic bags, paints, brooms used for cleaning, and others. This study showed that it is possible to use these plastic products in other ways to reduce the plastic pollution that invades the world, and one of these ways is the possibility of adding plastic to concrete to improve some of its properties. In this work, the bristles of plastic brooms are used in the form of fibers to improve the properties of concrete, and the results showed a significant improvement in the resistance to compression, flexural, and impact resistance of concrete, in addition to a slight decrease in the density. The fibers were added in different proportions (0.6, 1.0, and 1.4) as a percentage of the concrete volume, and the duration of the test ranged between (7 and 28) days for the tests of compression, flexion, and density, while the impact resistance tested at the age of 90 days.

Space and weight constraints, as well as the time lag between energy generation and consumption, ‎are major obstacles to expanding solar water heating systems into existing structures with limited ‎space. Collecting heat with this small, evacuated tube collector (ETC) is possible. It was found ‎that the air inside the glass tube has poor thermal conductivity. An experimental and numerical ‎study was performed on an evacuated tube solar collector, incorporating a heat tube with ‎cylindrical fins to increase the contact surface between the air and the fin surface. Statistical ‎analysis software is used to verify the results in practice. The temperature data was investigated ‎using SPSS under the same flow conditions. These figures are from experiments examining the ‎effect of variable volumetric flow rate, boost type, and variance analysis on temperature ‎distribution. When analyzing the results of the trials, a significant threshold of 95% was used. ‎Therefore, we compare the calculated significance to a value of 0.05 to evaluate the efficacy and ‎capabilities of the components. The reliability and validity of the model depend on the presence of ‎two components. If the resulting value is less than the significance level (0.05), then the model can ‎be considered robust and efficient (flow rate and optimization type). If the estimated value is ‎greater than that, the variables do not affect system performance. Flow rate and type of ‎enhancement are the two factors considered in the analysis of variance.

In this study, the heat transfer enhancement was made using multiwalled carbon nanotubes (MWCNTs) with distilled water (i.e . nanofluid) in a coiled agitated vessel. The thermal conductivity of the nanofluid at a volume fraction of (0.3 Vol%) was estimated with different parameters (temperature, propeller speed, flow rate, and time ultrasonication). The statistic program Minitab software 2019, using the Box–Behnken design (BBD) method, was used to identify the important and effective parameters of the process. The optimum parameters were found 55°C, 300 rpm, 1 L/min, and time ultrasonication of 100 min with enhanced thermal conductivity of about 76.5%.

In the current study, energy analyses were performed to enhance the characteristics and forced convection performance in the horizontal annular in the case of the presence of porous material and without porous material. Many types of porous material, porosities, and diameters were used. Computational fluid dynamics was used to simulate an annuli tube in the presence of porous material and without porous material by utilizing ANSYS FLUENT software 17.2. The working fluid utilized was water with Reynolds number from 100-500 and constant wall heat flux at 150 kW/m2. Two types of porous media glass and steel balls were utilized, two different porosities (0.6 and 0.7), and two different porous material diameters (12 and 24mm). Investigations occurred under the study state for studying heat transfer properties and fluid flow in the annuli tube. The energy analysis outcomes showed that there is a relationship between Nu and Reynolds number. The highest enhancement of Nu number happened at 12mm diameter and 0.6 porosity for bolls of glass and 0.7 for bolls of steel. The rising pressure drop occurs with the rising of Re for all cases, and the diameter of 12mm gives the maximum pressure drop for both steel and glass pellets, and the uppermost pressure drop occurs at a porosity of 0.6. Compared with those in the annulus in the absence of a glass sphere as porous material at the same ball volumes.