DIYALA JOURNAL OF ENGINEERING SCIENCES

Internal or liquid-suction heat exchangers are used with the main goal of ensuring the entry of refrigerant in the liquid phase to the expansion device. The greatest COP gain is primarily determined by the thermodynamic parameters linked to the relative increase in refrigerating effect. Large latent heat of vaporisation refrigerants often does not gain as much from condenser subcooling in support of a cooling system. Computational fluid dynamics (CFD) is used to study the effects of the turbulence model, which requires the solution of two transport equations. A technique was developed to study the thermal effect on the heat exchange process between two fluids. To observe the temperature effect on 17 tubes, the diameter was altered twice, first to 6 mm and then to 4 mm. The flow procedure transpired in one direction, and the tube housing the tubes had a diameter of 50 mm. In the best-case scenario, the pipe diameter is 4 mm, and the heat exchanger is 300 mm in length. The results indicate an improved enthalpy of 423.2 h [KJ/M] in the simulated cases. The length of the heat exchanger greatly affects the values of the exit temperatures and the temperature difference. For a length of 225 mm, the temperature reached 15.73 °C, and for 300 mm, it reached 13.847 °C. The significant reduction in temperatures increases the coefficient in the refrigeration cycle. A high coefficient of cooling in the heat exchanger appears when the length is 300 mm compared with other lengths.

Main seismic situations have appeared that the tunnels in weak soil may be suffer large seismic damage. Suitable modeling can have great significance for predicting and estimating their seismic acting. This paper examines the effect of the tunneling process and the seismic effect on the tunnel model and the surrounding soil on it. The data of this research is from Almafraq overhead intersection project in the Diyala government, the soil consists of clay and sand layers in which the tunnel is set up. The data obtained from field and laboratory investigations of soil layers and the analysis of the tunneling model by three-dimensional finite element analyses using PLAXIS 3D (V 20), the Mohr-Coulomb (MC) model is employed to demonstrate the behavior of soil-structure interaction in a soil tunnel. Plastic counting was used to act as an elastic-plastic distortion. Three sections are chosen in the vertical direction to experiment with the tunnel\'s impact and seismic effect on nearby soils. From proceeding FE analysis, the results of calculation by math measurement appeared to main variations in stresses that happen in soils zones nearby the tunnel edges and below the tunnel essentially affect nearness to soils. The increasing pressure becomes smaller as much as you went away horizontally from the tunnel and start to decrease for lengths more than 15m from the tunnel edge\'s, so it was observed that the most probable safe distance (2D) from the tunnel, which D represents the diameter of the tunnel, this for tunneling. Also, the upper zone of the tunnel considers safer at 58% because it is far from the influence of the earthquake and its soil is clay, while the critical zone locates in contact with the tunnel. Furthermore, it was noted that the amount of settlement of the soil is so little in a phase of tunnelling compared to the dynamic rate of 86%.

Dehydration of ethanol is one of the crucial processes as it is considered a green route for producing ethylene and diethyl ether and is promoted mainly by economics and environmental appeal. In this study, different kinetic models for ethanol dehydration to ethylene and diethyl ether were developed based on two parallel reactions and different mechanisms. Additionally, a mathematical model of a packed bed reactor was also suggested based on a set of hypotheses for investigating the axial concentration profile of ethanol. Kinetic parameters of each model were estimated by nonlinear regression analysis of obtained experimental data reported in the literature at temperatures between (523.15 – 623.15) K. The analysis showed that the single-site model I for ethylene formation and dual-site (LHHW) model for diethyl ether formation gave the best representation of experimental data compared to other proposed models. Kinetic parameters were found to be in good accordance with the Arrhenius equation with acceptable straight-line plots, and they have been satisfactorily correlated as functions of reaction temperature. The mathematical model presented a smooth linear change in ethanol concentration at various temperatures. The AARD% obtained for each chosen ethylene and diethyl ether formation model were about (1.4502-2.5978) and (0.9135-2.9394), respectively.

The fatigue life of aluminum alloys (7001–T6) and shot peening at various temperatures are predicted in this study. Shot peening (SP) steel balls is a surface treatment technique that can help minimize damage. This study set out to conduct an experimental investigation in order to ascertain the amount of damage caused by fatigue buildup for AA7001-T6 under rotating bending loading and a stress ratio R = -1. RT (room temperature), 330 °C, and SP + 330 °C were the temperatures used in the testing. To predict the fatigue life under high temperatures, it was suggested to use a modified damage stress model that had been established to take damage at different load levels into account. To determine the most damage (Miner's rule), the output of the current model was compared to experimental findings and the output from the fatigue damage model. The comparison showed that the current model had a respectable level of safety, whereas the miners' model had two models: one for low-high loading and the other for high-low loading, and the results were suitable for extending fatigue life. Despite the fact that H-L loading has a longer fatigue life (19477) cycles than the experimental (16433 cycles), L-H loading is conservative (Nf is 19477 cycles less than the experimental (24733 cycles) (non-conservative).

Chemical stabilization of soil is essential for construction work because it improves engineering characteristics of soil, such as swelling soil stability. The main objective of the research is to investigate the impact of adding Metakaoline (MK) on the behavior of expansive soil to reduce swelling. Different amounts of Metakaoline, such as 2 %, 4 %, and 6 % of the weight of dry soil, are used to prepare the soil specimens. The engineering properties of the soil sample are examined using a variety of laboratory tests (consolidation, swelling potential, and liner shrinkage) original and treated soil at various mixing ratios to determine the swell potential and swelling pressure. The findings showed that the addition of MK has caused a reduction in the swelling reaching about 91% with 4% MK at 14 days, Also, the swelling pressure decreased from 110 kPa to 30 kPa with 4% Metakaolin.

The historic city of Mosul, with its unique urban characteristics, is one of the few cities that is still inhabited, but the recent war has made it lose important and large parts of its traditional fabric, especially its distinctive riverfront. This research deals with the principle of Integrative Conservation as a conservation approach that is characterized by interest in both the urban and human dimensions, and it can provide adequate means to accomplish the process of preserving the historic urban fabric in a way that meets the contemporary requirements of life and preserves the historic value. The research aims to explore what are the criteria for Integrative Conservation most affecting the vitality of the historic urban fabric on the riverfront of Mosul old city. This is followed by the methodology of analysing previous studies to determine the most important Integrative Conservation criteria, and it is assumed that the accessibility and connectivity criteria are the most influential on the vitality of the city, using the Space Syntax to measure its indicators.

Infrastructure services are closely related to human life and development, as they are an essential indicator of the progress of life in countries. Infrastructure projects including the water sector are indeed the backbone of a country's economic development, providing many social, economic and environmental benefits. This paper aims to study the existing infrastructure (water sector) in Diyala Governorate, analyse the available data, prepare indicators of deficit ratios according to international standards, and propose possible solutions to address the problems in this sector. Data were collected for the water sector, which included the quantities of potable water supplied for the past eleven years. The results showed that the deficit rate in the water sector amounted to 32% in 2021, as evidenced by the deficit rates and the presence of clear deficiencies in the water sector in Diyala Governorate, and this deficiency does not result only from lack of availability, but rather due to a weak planning vision and the absence of future plans that take into account the increase in the governorate population. The results of predicting using simple linear regression using the Spss program version 26 showed that the demand for drinking water will reach 554,354 m³ per day in 2035. Three plans have been proposed to address the current deficit and future demand in the water sector, which is a short-term plan extending from 2022 to 2025, addressing 50% of the current deficit in 2021; A medium-term plan extending from 2022 to 2027 addresses the current deficit once and for all, and a long-term plan extending from 2022 to 2035 addresses the current deficit and future demand in the water sector.

Geotechnical engineers have a difficult time working with soft soils because they require a long time to reach their final settlement and drain water under pressure. Granular columns and other modern technology are only two of the many methods utilised to hasten this levelling. In this study, the alteration of clay soils with a granular column and the evacuation of water by an electric field were replicated using 2D engineering and a finite component. Solid mechanics and electrical interfaces were built using the drag interface. Mohr–Coulomb theory relies on a granular column and fine clay soil at the mechanical contact and employs electro-osmosis to describe a model’s electric field’s impact. For a period of 6 months, the pore water pressure for fine clay soil was calculated. Result showed that when the electric current was applied with a voltage of 5 V, the pwp in soil increased in the first 2 months and then began to decrease gradually, reaching 120 kPa in the sixth month. When the applied voltage was increased to 15 V, the pwp decreased in the first 2 months from the previous ratio of voltage, then it began to decrease gradually and reached 70 kPa in the sixth month. When the applied voltage was further increased to 30 V, the pwp in the soil decreased in the first 2 months from the previous ratios of voltages, then it began to decrease gradually and reached 40 kPa. The percentage of water leaving the soil when an electric current of 5–15 V was applied was 64%. When the voltage was increased to 15–30 V, the value became 75%. That is, as the applied voltage increased, more water was discharged from the soil. The soil settlement also increased with an increase in voltage. The improvement percentage and the percentage of water leaving the soil were 50% at 5–15 V and 71% at 15–30 V.

In this study, Peng-Robinson equations of state associated with three different mixing rules used to predict the experimental solubility data of two acid gases, carbon dioxide and hydrogen sulfide in seven ionic liquids. The solubility data were obtained from different literature in pressure range (0.119 – 65.2) bar and verity range of temperatures (298.2 – 353) K. Mixing rules, used the modified Van der Waal (MR1), the Quadratic (MR2) and the Wong Sandler (MR3). The ionic liquids critical properties were correlated by modified Lydersen-Joback-Reid technique. The Average Absolute Relative Deviation (%AARD) was applied to compare the experimental data and that obtained from the model. The evaluated critical properties give a very close result with the literature. The mathematical model in almost systems using the three mixing rule gives good agreement with experimental data only in H2S - ILs systems gives very high deviation from the experimental data when use MR3. Quadratic mixing rule (MR2) was the best comparing with MR1 and MR3, give the lowest range %AARD 0.9 to 21.

Building maintenance is one of the critical issues that maintenance managers should prioritize. As a result, evaluating the performance status of maintenance is required to understand the reality of maintenance in construction projects and to ensure that maintenance meets the required goals and improves building preservation. Therefore, the aim of this study is to evaluate the state of building maintenance performance in construction projects. The field survey included preparing a list of the questionnaire, conducting a statistical analysis of a Sample Questionnaire, and discussing the results. Note that the research has achieved practical results The results showed that the average value for the axis (encouragement/development) reached (2.31), which is the lowest value in the questionnaire, showing that was an absence of professional development and employee training through a training course, as well lack to carry out follow-up work on the status of performance of the functions of the main building elements, in addition to the scarcity of taking into account the design, construction phase and how to perform maintenance, and therefore the failure to apply these factors will harm the process maintenance and efficiency.

Thermoacoustic refrigeration is among the best alternatives to conventional refrigeration systems because of the use of inert gases for instance helium or air. On the contrary, refrigerants used in some conventional refrigeration systems are very harmful to the ozone layer and can contribute to global warming problems. In addition, in the event of their leakage, they cause harm to humans. Thermoacoustic technology can be described as a clean, renewable technology. The thermoacoustic refrigerator's main function is to utilize sound waves to create a cooling effect. The aim of this research is to design a standing wave thermoacoustic refrigerator driven by an acoustic driver using the simulation program DELTAEC to achieve high cooling capacity and improve the coefficient of performance. In addition, it discusses the design process. Besides that, the influence of significant stack and resonator parameters (inertance and compliance) is discussed in order to assist thermoacoustic researchers in better understanding and designing the thermoacoustic refrigerator. According to the results obtained, the designed thermoacoustc refrigerator performed best. It has achieved a cooling load (cooling capacity) of 312W and a COP of 1.9275 at a difference in temperature of 25K between the AHX and CHX.

Induction machines are a crucial type of electrical equipment utilized as motors in various industries and single-phase forms in household applications. They make up more than 80% of the industrial motors used today. This paper presents a dynamic simulation of three-phase induction machines based on the (d-q) model, providing a clear and easy-to-understand explanation of the behavior of the induction motor in the synchronous reference frame. The simulation is implemented using SIMULINK/MATLAB software, and full-order model analysis is conducted for transient analysis. However, modeling induction machines as part of power system analysis can be done with a less detailed model than the full-order one. In this paper, a reduced-order model is employed to simulate the induction motor using MATLAB/SIMULINK. The results of the reduced-order system and the full-order framework are compared to investigate the model's limits, and the computational benefits of saving time during large power system simulations justify the relative decrease in accuracy. The use of a reduced-order model results in a significant reduction in computation time when simulating large and very large-scale power systems, with a much higher accuracy in transient analysis than the conventional steady-state model.