Journal of Engineering

his paper investigates the impact of electromagnetic pollution in some hospitals and schools in Al-Najaf City. The study focuses on the power density (PD) measurements and specific absorption rates (SAR) in these locations. A field survey was conducted on six major hospitals and 38 schools distributed over the central neighborhoods in Al-Najaf City. The results showed that PD measurements for four out of six hospitals and 27 out of 38 schools were higher than the biological limit (BL) adopted in this study, indicating potential harmful effects on brain and body tissues. The highest PD value recorded was 5.62 mW/m² in Al-Sadr Teaching Hospital. When compared with the limits set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), the PD measurements were below the recommended limit. However, SAR values were above the biological limit for four hospitals and several schools. The study highlights the need for measures to mitigate electromagnetic pollution in these sensitive areas.

This paper investigates the flow in manifolds, which is considered an advanced problem in hydraulic engineering applications. The objectives of the study are to determine the uniformity (qn/q1 ratio of the discharge at the last outlet, qn, to the discharge at the first outlet, q1) and total head losses of the flow along straight and rectangular loop manifolds under different flow conditions. The straight pipes were 18 m and 19 m long with a diameter of 25.4 mm (1.0 in), while the rectangular loop configuration had a length of 19 m and a diameter of 25.4 mm (1.0 in). A constant head of 2.10 m was used in the supply tank. The study found that outlets spacing and manifold configuration are the main factors affecting the uniformity of flow distribution and friction head losses along manifolds. For larger outlet spacing, the uniformity coefficient was found to be 0.96, indicating improved flow distribution. The rectangular loop manifold showed better uniformity and lower friction head loss compared to the straight manifold.

This paper introduces a complete design and simulation of a controller for the double fed induction generator (DFIG) turbine utilized in a solar updraft tower (SUT). The design includes daily average load estimation, annual solar irradiance, and temperature monitoring and logging. Due to low wind speeds in Baghdad, the SUT was designed to generate electrical power based on the temperature difference between external and internal air. The proposed controller uses vector control with a PI controller to feed the power of the rotor circuit parts. The DFIG consists of two back-to-back PWM inverters connected between the stator and the rotor. The goal is to design and simulate a controller for two DFIGs under various operating conditions driven by a wind turbine rotated by the warm wind effect inside the SUT. The controller maintains the magnitude and frequency of the output voltage constant and stabilizes irrespective of wind speed variations, extracting maximum output power. The controller also provides maximum power point tracking (MPPT) to the turbine according to the available wind speed. Simulation results using MATLAB/Simulink confirm the controller's performance, demonstrating better stability and faster response.

This paper investigates the mobilized shaft resistance of axially loaded, long slender piles embedded in dense, dry sand when subjected to pullout force. The study includes both experimental and numerical analyses. The experimental setup involved an instrumented model pile, while the finite element method was used for numerical analysis. The hypoplasticity model was employed to model the soil adjacent to and surrounding the pile using ABAQUS FEA (6.17.1). The soil-structure interface behavior was examined under different confining pressures and surface roughness conditions. The results showed a dilation behavior for piles with rough and medium roughness surfaces, while contraction behavior was observed for smooth surfaces. A significant shear strength degradation of about 10% was noted under low confining pressure, compared to a lesser reduction of about 2% under high confining pressure. Good agreement was found between the experimental and numerical results.

This paper explores the use of microbially induced calcite precipitation (MICP) as an innovative and sustainable ground improvement method for soft clay soils. The study utilizes ureolytic bacteria, specifically locally isolated Bacillus sonorensis from Iraqi soil samples, to produce calcite and enhance soil strength1. Three concentrations of the bacteria (0.25M, 0.5M, and 1M) were tested. The results showed significant improvements in the unconfined compressive strength of the soft clay, with increases ranging from 3 to 5 times for certain bacterial strains1. This technique offers a sustainable approach to soil stabilization in the construction industry.

This paper presents numerical and experimental studies on the elastic behavior of glass fiber reinforced polymer (GFRP) with stiffeners in the GFRP section's web to prevent local buckling. The GFRP profiles were connected to the concrete deck slab by shear connectors. Two full-scale simply supported composite beams (with and without stiffeners) were tested under impact load (three-point load) to assess their structural response. The results showed that the maximum impact force, maximum deflection, damping time, and damping ratio of the composite beam were affected by the GFRP stiffeners. The experimental results indicated that the damping ratio and deflection were diminished compared to the hybrid beam without stiffeners by 16% and 22%, respectively, and increasing damping time by 26%. Finite element models were used to study pre-failure behavior. The numerical modeling results showed good agreement with experimental data in terms of loading path and final load. The damping ratio and midspan deflection values were greater than the experimental values by 6% and 12%, respectively.

This paper presents a study on the assessment and management of groundwater quality in Baghdad, Iraq, using Geographic Information Systems (GIS) and the Water Quality Index (WQI). The study utilized five chemical parameters, including Electrical Conductivity (EC), Chloride (Cl-), Bicarbonate (HCO3-), Sodium Percentage (Na%), and Sodium Absorption Ratio (SAR), to create a database of water quality. These parameters were inputted into the GIS platform to produce spatial distribution maps for each parameter using the inverse distance weighting (IDW) technique. The WQI values were also reassigned to the GIS environment to generate IWQI maps. The results showed that only 25% of the studied samples fall in the Low Restriction (LR) category, indicating that this water can be used for irrigation purposes without reservation. However, 94% of the groundwater was found to be moderate to highly restricted for use in irrigation and can be used only in soils with high permeability without compact layers, requiring moderate leaching of salts. The map results also showed that 26% of the studied water samples should be avoided and not used for irrigation under normal conditions because they fall within the Severe Restriction (SR) categories.

This paper explores the properties of porous asphalt concrete, which is a modern paving method that allows the free passage of fluids through its layers, thereby controlling or reducing runoff and water accumulation. The study tested the volumetric and physical properties of the porous mixture and examined the use of carbon fibers as a mixture improver1. The best gradient for the porous asphalt mixture was selected based on the largest proportion of air voids, and the optimum asphalt ratio was determined according to standard specifications. Samples were prepared with and without carbon fibers and tested using a Marshall device to calculate stability and flow values1. The results showed an increase in stability and a decrease in flow and drain down rate for samples containing carbon fibers.

This study explores the potential of a local sustainable energy network in a pre-existing context to develop a novel design beneficial to the environment. The concept of smart cities is still in the developmental phase, and it is crucial to discover new solutions that show direct benefits to the people by transforming their city from a traditional to a smart city. Using experience and knowledge from successful projects in various European and non-European smart cities, this study demonstrates the practical potential of gradually moving existing cities to the level of smart cities by developing available environmental resources. Data shows that using residual heat in a small neighborhood results in a lower annual gas consumption of at least 732,200 m³, leading to a reduction of CO₂ emissions by 1,303,316 kg.