Journal of Engineering

The research addresses one of the costliest problems in hydrocarbon production from unconsolidated sandstone reservoirs: sand production. The study developed a computer program to predict the onset of sand production by estimating the critical pressure drop. The results indicate that the pressure drawdown required to produce free sand oil flow rate decreases with increasing skin factor. Additionally, free sand oil production cannot be prevented at a well-flowing pressure of 500 psi. The outcomes are presented as a function of free sand production with critical flow rates for reservoir pressure decline.

The study investigates the dynamic behavior of a concrete foundation under combined dynamic and seismic loads. The foundation is modeled on the top surface of one-layer dry sand with various states (loose, medium, and dense). The dynamic investigation is performed numerically using PLAXIS 3D software. A harmonic load with an amplitude of 10 kPa at frequencies of 10, 15, and 20 Hz is applied, along with a seismic load based on the acceleration-time input of an earthquake that hit Halabjah city, north of Iraq. The study evaluates the effects of relative density, embedded depth, and frequency on the foundation's performance. Results indicate that relative density significantly affects the resistance to settlement, with denser soils providing greater resistance. Additionally, increasing the embedding depth reduces total stress and displacement, while changes in frequency from 10 to 20 Hz decrease displacement.

The study reviews previous research on designing LPG systems for residential buildings. LPG, consisting of propane, butane, or a mixture of both, is extracted from natural gas and refined. The review highlights safety concerns, such as gas leakage, which can lead to fires or explosions. Recommendations include placing gas leak detectors at specific distances from the gas source and above the ground. The study emphasizes the need for new techniques using hardware and software components to ensure fast and effective results.

The study evaluates and develops the Hilla-Daghara rivers system, which includes Shatt Al-Hilla and Shatt Al-Daghara. Fieldwork was conducted from October to December 2020 using M9, S5 devices, and staff gauges to measure discharges and water levels. A one-dimensional model was developed using HEC-RAS, calibrated and verified by field measurements. The discharge capacity in Shatt Al-Hilla and Shatt Al-Daghara was found to be 200 m³/s and 50 m³/s, respectively. Four development scenarios were simulated to improve the capacity of Shatt Al-Hilla to 303 m³/s and Shatt Al-Daghara to 75 m³/s. The earthworks volume for development was estimated at 5.89 Mm³ for Shatt Al-Hilla and 0.54 Mm³ for Shatt Al-Daghara, with costs of 11.780 billion IQD and 1.080 billion IQD, respectively.

This paper provides an overview of self-repairing technology based on microcapsules for cementitious composites. The technique involves releasing self-repairing factors from microcapsules when cracks occur in concrete. The review discusses various repairing factors, investigative methodologies, and assessment criteria. Nondestructive methods are commonly used to evaluate the self-repairing behavior. However, challenges such as crack spread behavior, repairing agent kinetics, and the impact of capsules on mechanical properties require further investigation.

The analysis of rigid pavements is complex due to cyclic loads causing fatigue and climatic conditions affecting performance. The study uses ABAQUS software to simulate the response of fiber reinforced concrete pavement under dynamic loading. Good agreement was observed between laboratory and finite element results, with maximum differences in ultimate loads and deflection being 6% and 8% for monotonic loading, and 10% and 18% for repeated load.

This paper focuses on the stone matrix asphalt (SMA) technology, which is developed to guard against rutting distress. Fibers play a crucial role in stabilizing and preventing the drain down problem caused by the necessity of high binder content coupled with their strengthening effect. A set of specimens with cylindrical and slab shapes were fabricated by including jute, polyester, and carbon fibers. For each type, three contents of 0.25%, 0.5%, and 0.75% by weight of mixture were added by lengths of 5, 7.5, and 10 mm. The prepared mixtures were tested to gain the essential parameters discriminated by the values of drain down, Marshall quotient, rut depth, and dynamic stability. It has appeared that the fibers rate of 0.5% and 7.5 mm length is much appropriate to yield the best performance of modified mixtures. At these values, carbon fibers recorded the highest increase level of rutting resistance and dynamic stability by 53% and 100%, respectively, while jute fibers exhibited the lowest improvement by only 34% and 63%, respectively. Nevertheless, they produced mixtures having the lowest drain down value. Regarding the index of plastic stiffness, polyester fibers embedded mixtures occupied the first rank of increasing by 38%.