Journal of Engineering and Sustainable Development (JEASD)

This article presents design and simulation of a new compact four-element dual-band MIMO frequency reconfigurable antenna that can be reconfigured for WiMAX and LTE applications. The antenna includes four elements at the same FR4 substrate with an optimized overall size of 65x65x1.6 mm3 and an optimized partial GND plane of 30x11.125 mm2. The reconfiguration rate is between 2.41 and 3.99 GHz that can cover the WiMAX and LTE wireless devices by applying just one RF (PIN) switch to change the operating frequency. The antenna operates on the two states of the PIN diode under its two states ON and OFF with (2.7 GHz, and 2.8 GHz) resonant frequencies respectively. The proposed antenna produces acceptable simulation results for the MIMO system by achieving gain from (3-7.2) dBi, less than -14.5 dB coupling effect, less than 0.28 envelope correlation coefficient, and diversity gain range from 8.4-10.

In concrete when tensile stress surpasses the strength of the traction contributes to cracking, which is called shrinkage cracking. Shrinking allows for curling and folding of concrete. The principal goal of this research work is to develop optimal Eco-friendly concrete mixtures by using Response Surface Methodology (RSM), including different quantities of polypropylene fiber used in concrete pavement, identify the shrinkage factor (shrinkage cracking) in the concrete pavement. The testing program included using of thirty mixtures to investigate four parameters namely cement content (300,400 and 500) kg / m3, steel fiber (0, 0.075, and 0.15 vol. %), three separate amounts of polypropylene fiber (0, 0.35, and 0.7 vol. %), and (0, 5, and 10 %) silica fume by cement weight. The results indicated that the amount of cement is the higher factors affecting the shrinkage cracking of concrete. For the purpose of obtaining the best mixture for optimal components to design concrete mixtures used in the concrete pavement that give the compressive strength [> 30 MPa], flexural strength [> 4.1 MPa], minimum CO2 emissions, less cost, and fewer cracks width according to requirements and Iraqi specifications are cement [385.94] kg/m3, silica fume [0.000198Vol.%], steel fiber [0.0564 Vol.%], PP fibers [0.2926 Vol.%], Carbon dioxide emissions [379.59] kg CO2 -e / m3, total cost 99.96 USD / m3, and crack width [0.1]mm.

The purpose of this paper was concerned of the behavior of six samples of deep beams under the influence of pure torsion. Such samples were self-compacting concrete (SCC) and two ratios of Steel Fibers (SF (were also added (0.75 % and 1.5 %). This study examined the behavior of the samples when pure torsion was applied and reacted to angles of torsion, longitudinal strains and concrete strains. It was obvious from the results of the test that the addition of steel fiber to the SCC mixture increased the strength of the compression and tensile strength, which increased the hardness of the samples, thereby decreasing the response of the samples to the angle of twisting, longitudinal strains of concrete and concrete strains.

Tigris River is the only potable source in Baghdad city therefor many water treatment plants were built on the banks such as Al-Karkh, Sharq Dijla, Al-Sadr, Al-Wathba, Al-Karama, AlQadisia, Al-Dora, Al-Wahda, and Al-Rashed project. Tigris River suffers from the pollution that comes from various sources such as Industry, domestic sanitation, and farming activities therefore several indices were used to calculate water quality within Baghdad to convert physicochemical parameters of water to a single value that represents the river status (good, bad, very bad, etc..). The aim of this review paper to show the results of previous studies about the water quality for the Baghdad region. Most results showed that water quality was good in the north of the city of Baghdad and bad in the south of Baghdad. The deterioration of water quality was due to many reasons such as the discharge of wastewater directly into the river without pretreatment, increase in (Eclectic conductivity, Turbidity, and total suspended solids, total hardness, Iron ion, the fecal coliform) concentrations, and Climate change, therefore, Tigris River needs intensive treatment before using by humans.

The Tigris River is the most important source of water in Iraq; however, it suffers from the impact of pollutants that disposal directly into it. In this study, the Water Quality Index (WQI) of 7 of the chemical properties (Cl-, NO3, SO4, COD, BOD5, Ca, Mg) in the Tigris River, Baghdad, Iraq was analyzed to measure the impact of liquid waste discharge in the city of medicine on the river from January to October 2020. Three points were selected as the sample location, the first point was 700 meters before the discharge point, the second point was the discharge point, and the third point was 400 meters after the discharge point. The findings revealed that the concentration of all the measured components at the region where the sanitary discharge point site2 was situated was much higher than that of the location before the sanitary discharge point site1. For example, in January Cl- the concentration at site1 was (350 mg/l) relative to site2 the concentration at (1200 mg/l). In comparison, the concentration of the constituents in the area after the sanitary discharge point site 3 was lower than that of the sanitary discharge point area site2. In addition, Cl- concentration at site3 was (750 mg/l) lower than site2 (1200 mg/l) but still higher than site1 (350 mg/l). The lower concentration at site3 suggests that the water body of the river is being diluted; however, this is not a solution as the causes of pollutants of the river are various. Most of the findings have shown that the permissible cap for the Iraqi standards and the World Health Organization (WHO) for the river maintenance system has been surpassed.

This paper explores the sizing optimization of stand -alone hybrid energy system (HES) in southern Iraq (Thi Qar province) for supply stand-alone households by the electricity. HES consist of three components (solar cell (PV), diesel generator (DG) and battery storage (BS)). Particle swarm optimization (PSO) used in this study for find optimal sizing of the HES to minimizing multi-objective, first objective is to minimizing the total system cost (TSC) that lead to minimizing cost of energy (COE). Second objective is to minimizing total emission CO2 (TECO2). The constraint of the optimization is the reliability (100 %) mean continuous provide the load demand by the electricity. The results of the optimization show the ability the algorithm to minimizing the multi-objective with continuous supply the load by the electricity through life cycle of the project (25) years.

This study presents an analysis of meteorological drought using multi time-scales of Standardized Precipitation Index SPI (6, 9 and 12 month), based on observed 49-year daily mean precipitation data records at 11 stations over the Northern region of Iraq. The detection of drought trends in results of SPI analysis was studied to identify whether there is any increase or decrease in the severity of drought at the selected meteorological Stations; Mann Kendall test and Sen's slope estimator were used to detect statistically significant trends. The results indicate that there is a statistically significant decreasing trend of SPI time series at 5% significant level in most of the selected stations. Based on drought categories the meteorological drought in the study region can be classified as mild drought.

Using epoxy to repair concrete crack is widely used for restoring concrete structure. Epoxy is used as a base material in composite materials with fillers to improve mechanical and physical properties. The study aims to modify the properties of the epoxy by adding (alumina, silicon carbide, silica fume, pumice) and using This compound is for repairing concrete cracks. Each of the materials (alumina, silicon carbide, silica fume, pumice) were used to harden the epoxy in different proportions (5, 10, 15) by weight. It has particle sizes (45 - 65μm), to prepare composite particles that can be used in construction applications. Further tests are performed to verify whether or not composites are suitable for applications. For the crack repair application, the resulting composites were tested for compression and bending. The resulting compound was applied to treat cracks in previously prepared concrete samples and several tests were performed (compression, bending, and UPV) to determine the effectiveness of this compound in treating cracks in the structural elements.

This study was conducted to assess the water quality of Tigris River within Baghdad city by using Weighted Arithmetic model. The studay area included five sites: Thiraa-Tigris (S1), Al-Muthana bridge (S2), Al-Shuhadaa bridge (S3), Al-Doraa (S4) and confluence point of the Diyala river (S5). Ten water quality parameters were used in this study, Total Hardness (TH), Calcium (Ca), Hydrogen Ion concentration (pH), Chloride (Cl), Magnesium (Mg), Nitrate (NO3), Sodium (Na), Boron (B), Turbidity (TUR) and Sulfate (SO4). Statistical analysis such as correlation and regression coefficient using the statistical program SPSS was used to evaluate the results of the water quality index as well as to find a relationship between the water quality index and the variables. Several statistical methods, Factor Analysis (FA), Principal Component Analysis (PCA), Discriminant Analysis (DA), and Time Series Analysis assess parameters affecting water quality during the study period (August-December) 2019. The results showed Poor to Unsuitable quality index in Tigris River at Baghdad city except for Al-Muthna Bridge (S2) was grade good quality index during the time. From the analysis, that the worst water quality index was found at confluence place of Diyala River (S5) and grade unsuitable quality index.