Journal of Engineering

Twisted tape insertion in the smooth plain tube is one of the types of passive methods used to enhance heat transfer. Swirl fluid flow inside the tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with a twisted tape of twist ratio of y = (H/D) = (150/17) =8.8 along the plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nusselt number and overall enhancement ratio results are presented for both empty and inserted plain tube with a comparison between the two cases. An increase of 0.76 to 2.36 overall enhancement is predicted with twist ratio 8.8 for Reynolds number 784 to 7000 respectively.

An experimental investigation has been made to study the influence of using v-corrugated aluminum fin on heat transfer coefficient and heat dissipation in a heat sink. The geometry of the fin is changed to investigate its performance. 27 circular perforations with 1 cm diameter were made. The holes were designed in two ways: inline arrangement and staggered arrangement along the corrugated edges. The experiments were conducted in an enclosure under natural convection. Three different voltages were supplied to the heat sink to study their effects on the fins' performance. All the studied cases were compared with a v-corrugated smooth solid fin. Each experiment was repeated twice to reduce error, and data were recorded after reaching steady-state conditions. The results showed that the v-corrugated fin dissipated heat two to three times more than a flat plate with the same dimensions mentioned in past research. Additionally, the inline perforated fin showed higher enhancement percentages than the solid one by 15%, 32%, and 36% for 110V, 150V, and 200V supplied voltages, respectively. Finally, the staggered perforation arrangement provided the highest enhancement percentages with 22%, 42%, and 45% for the same supplied voltages.

Petroleum refineries generate significant amounts of oily sludge, posing environmental threats if untreated. This study explores a hybrid process combining ultrasonic treatment with froth flotation to treat oily sludge from the bottom of crude oil tanks at Al-Daura refinery. The optimal conditions—30 minutes treatment time, 60-micron ultrasonic wave amplitude, and a solvent-to-oily sludge ratio of 4—yielded a 65% base oil recovery. Additionally, 83% of the solvent was recovered, and the separated water was reused. Among three sonic probes tested, results indicated that exceeding optimal ultrasound intensity adversely affected process efficiency. Incorporating 0.05% NaOH increased oil recovery from 50% to 65%. This hybrid method offers an environmentally friendly solution for treating refinery-produced oily sludge.

In this study, polymeric ultrafiltration (UF) membranes were prepared by the phase inversion method to obtain both antibacterial and organic antifouling properties. The membranes were cast from a solution of polyvinylidene fluoride (PVDF), and formative silver (Ag) nanoparticles were successfully immobilized on the polymer. This was done using N,N-dimethylformamide (DMF), which serves as a solvent for the PVDF polymer and a reducing agent for silver ions. The effect of silver nanoparticles additives on the performance of the polymeric ultrafiltration membrane was verified. Chemical composition and morphology of the membrane surfaces were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antibacterial property of the modified membrane and the influence of silver nanoparticles on pure water flux of the composite membrane at 0.2 MPa were also examined. The experimental results concluded that the composite membrane properties were improved by the integration of Ag nanoparticles. The grafted membrane with silver nanoparticles demonstrated a clear ability to inhibit the growth of E. coli, Pseudomonas aeruginosa, and Bacillus cereus, whereas the pure PVDF membrane (without any additives) did not show any effect in preventing the growth of these bacterial species. The pure water flux, porosity, and mean pore size of the composite membrane reached 261.8 L/m²·h, 85.4%, and 0.0206 µm, respectively, which were significantly higher than those of the pure PVDF membrane.

Utilizing modern technologies in agriculture, such as subsurface water retention techniques, has been developed to improve water storage capacities in the root zone depth. Moreover, this technique maximizes the reduction in irrigation losses and increases water use efficiency. In this paper, a polyethylene membrane was installed within the root zone of okra crop during the spring growing season of 2017 inside a greenhouse to improve water use efficiency and water productivity of the okra crop. The research was conducted in a field located in the north of Babylon Governorate in Sadat Al Hindiya Township, seventy-eight kilometers from Baghdad city. Three treatment plots were used for comparison using a surface trickle irrigation system: Polyethylene sheet (SWRT) in plot T1, controlled irrigation in plot T2, and uncontrolled irrigation in plot T3. Irrigation quantities, time of irrigation, and soil water contents were measured for all treatment plots. The results indicated that water use efficiency for the three experimental plots, T1, T2, and T3, were 2.43, 1.94, and 0.98 kg/m³, respectively. The increase in water use efficiency of the T1 plot compared with T2 and T3 plots was 25% and 148%, respectively. Additionally, the water productivity of okra crop for T1, T2, and T3 plots was 12,800.9, 8,744.8, and 4,736.3 ID/m³, respectively. The increase in water productivity of T1 compared with plots T2 and T3 was 46% and 170%, respectively. From this study, the benefit of using a membrane sheet below the soil surface resulted in an increase in yield, water use efficiency, and water productivity. Moreover, it saved water and reduced water losses by deep percolation.

This research investigates the structural behavior of reinforced concrete columns made of normal and hybrid reactive powder concrete (hybridized with steel and polypropylene fibers) when subjected to chloride salts at a concentration of 8341.6 mg/l. The study comprises two parts: an experimental study and a theoretical analysis. Three main variables were considered: concrete type, curing method, and loading arrangement. Twenty columns with dimensions of 120x120x1200 mm were cast and tested based on these variables. The columns were reinforced with Ø8 ties and Ø12 longitudinal bars, maintaining a minimum longitudinal reinforcement ratio of 0.01Ag. The specimens were divided into two main groups according to curing method: the first group consisted of ten columns cured in tap water for 28 days, with five columns each for normal and hybrid concrete. The second group comprised ten columns directly cured and fully immersed in chloride water (8341.6 mg/l) for six months, also with five columns each for normal and hybrid concrete. The specimens were tested under three types of loading: axial load, eccentric load with three different eccentricities (50, 100, and 150 mm corresponding to e/h ratios of 0.42, 0.83, and 1.25, respectively), and as beams. Experimental results indicated an increase in ultimate load capacity and higher chloride resistance for hybrid reactive powder concrete compared to normal concrete in both curing conditions (tap and chloride water), as evidenced by strain profiles. Interaction diagram charts were developed for different loading types for each specimen, showing higher values for hybrid reactive powder concrete compared to normal concrete.

This study aims to show the strength of the steel beam-concrete slab system without using shear connectors (known as non-composite action), where the effect of the friction force between the concrete slab and the steel beam has been investigated using finite element simulation. The proposed finite element model has been verified based on comparison with experimental work. Then, the model was adopted to study the system strength with different steel beam and concrete slab profiles. ABAQUS has been adopted in the preparation of all numerical models for this study. After validation of the numerical models, a parametric study was conducted, with linear and non-linear regression analysis. An equation regarding the concrete slab-steel beam system strength in non-composite action has been pointed out. The actual strength of the beam without using shear connectors has been located between full composite action and non-composite action. However, partial-composite action has been noted due to the effectiveness of friction force, which makes the beam behave as composite before the slip occurs.

The avoidance of failure in construction projects is not an easy task, which makes the failure of the construction project to achieve its objectives a major problem experienced by all countries in the world, especially Iraq. Where nearly two-thirds of the construction projects in the world have been suffered by significant problems as an increase in the cost of the project, delay in the specified duration for execution, and stopping the project. Therefore it is required to study and apply new methods for managing the construction project to ensure its success and achieve its objectives. The aim of this study is to study the Agile project management method and its impact on the construction project. In addition, to identify the values and principles of Agile project management, which can be applied in the Iraqi construction industry to be adopted it as a new method to manage the construction projects in Iraq. The researcher reviewed the relevant literature to define the method of Agile project management and its methods and impact on the construction project. Then, the researcher conducted a questionnaire survey of a sample of engineers' experts who work in four main parties in the construction project: (beneficiary, supervising, designer, and contractor). The results of this survey showed that it is possible to apply the four values of Agile project management for managing the Iraqi construction projects, and can apply eleven of the twelve principles of Agile project management for managing the Iraqi construction projects.