KUFA JOURNAL OF ENGINEERING

In this paper, the melting processes of phase change material in a shell and tube heat exchanger by using solar thermal energy have been investigated numerically and experimentally. All experimental were outdoor tested at AL-Mussaib city-Babylon-Iraq (Lat 32.5 º North, and long 44.3 º East) with N-S collector direction at tilt angle of 32.5 º with the horizontal. The phase change material used in this work is black color Iraqi origin pure Paraffin with amount of 12 kg. In the experimental setup evacuted tube solar collector is employed for melting phase change material in shell regime. Different volume flow rates for the water flow inside the inner tube of heat exchanger namely (200, 300, and 500 LPH) for Reynolds number namely (15000, 23000, 38000) respectively were used for each season from August 2016 to January 2017. The numerical investigation involves a three dimension numerical solution of model by a commercial package ANSYS FLUENT 15.0. The boundary conditions of the model that solved by the numerical solution have been taken from the experimental tests. The experimental results indicated that the inner tube inlet and ambient temperatures has a significant effects on the melting process compared with the volume flow rates. Studying phase change material temperature distribution, it is exposed that a melting temperature of the phase change material in summer season needed time of (3-4) hours only, while it needed more time; (14-16) hours in winter season. Increasing solar radiation and ambient temperature reduces the melting time of phase change material. Increasing water temperature difference of inner tube increased the heat gained for phase change material. The results obtained from numerical solution presented the static temperature contours and showed that the temperature distribution of phase change material give good validations with experimental results with percentage deviation of 2.7%. The present experimental results have been compared with the previous studies and give a good agreement with increasing for present work of 25.9 %.

This paper presents experimental study to retrofitted reinforced concrete Hollow Section Bridge. The study was carried out on the White River Bridge structure (Bai xi da Qiao / China). The effect of retrofitting on stress and strain of beams at the critical section was studied. Evaluating the bridges girder after strengthening using new material called Polyurethane- Cement material (PUC) as an external material .This study present the strain and deflection before and after strengthening the bridge girders. The results has shown that the overall state of the bridge structural strengthening is in good condition. The enhancement was significant in stiffness of the bridge structure. Regarding to the results of static load test, the experimental values strain and deflection are less than theoretical values, indicating that the stiffness of the structure, overall deformation and integrity satisfy the designed and standard requirements and the working performance are in good condition, and flexure capacity has a certain surplus.

Three parabolic trough collectors, with its two axes sun manual tracking system were designed, constructed, and operated in order to generate hot water and moderate temperature steam. An experimental investigation for testing the performance of a PTC is presented. The tests have been carried out in NAJAF climatic conditions (32.02º N, 44.33º E) during selective days of August. The thermal performance of PTC evaluated according to the Standard ASHRAE 93-1986 (RA 91) and the efficiency curve for the PTC was estimated. In the performance analysis of the PTC array, the effects of collector inlet temperature, ambient conditions, two cases for glass receiver and the variation in mass flow rate of the working fluid were investigated. The tests were performed by collecting the data the outdoor measurements to evaluate the instantaneous thermal efficiency for PTC. A peak efficiencies close to (50%, 18.8%) were obtained for solar collectors with evacuated and non-evacuated glass receiver respectively at higher flow rate. The collector efficiency equation that is obtained in the present work agrees with other researches.

A number of studies have been conducted to specify the most effecting factors on the success of projects. Those studies titled the most influencing factor, which is the bid selection criterion. By this criterion, the most qualified bidder/contractor could be chosen where the contractor has a considerable impact upon projects successes. Moreover, the published studies helped a lot in correcting the improper adopted criterion in selecting the best bid, which is the lowest price bid. Awarding the bid depending on the lowest price bid ended many projects in failure. Therefore, this study aimed to revise the popular mistaken selection criterion, recommend an evaluation criterion, and develop a computer program that works on finding the best bid according to the recommended criterion. The suggested criterion was followed in selecting one of the contractors to construct some projects in Iraq. That projects were felicitously finished; the projects were completed on time and budget.

This study investigates the effect of Nano-zinc oxide on tensile properties of natural rubber composites by replacing the conventional zinc oxide by Nano-zinc oxide as an activator. It has a small particle size and large surface area in comparison with conventional zinc oxide. In this paper, one compound has a conventional zinc oxide as an activator with concentration 8phr (part per hundred rubber), and eight compounds have Nano-zinc oxide as an activator with concentrations of (0.2, 0.6, 1, 1.4, 1.8, 2.2, 2.6, and 4) phr. The tensile test sample carried out by using the Monsanto T10 Tensometer. Results showed that the maximum values of tensile strength and elastic modulus at 300% are found with Nano-zinc oxide at 1.8 phr. Replacing the conventional zinc oxide by Nano-zinc oxide decreased the price of the compounds because of reducing the amount of zinc oxide inside the compounds by 77.5%. It also reduced the contamination of the environment and improved the tensile strength by 38.31%.

Researcher design an ionic system to adsorb ions from industrial water of companies and factories, system consisted of three integrated phases designed to test the efficiency of an unspecified number of residues of food as adsorb materials. We adsorb copper and cobalt ions, these ions are available at high rates in Al Musayab thermal station, high concentration of these ions pose a threat to the health of the population. In general, the presence of these ions in the proportions set by the World Health Organization, namely, (1mg/L) are very useful for the completion of the metabolic processes of the living cell, but a greater focus for this will lead to tremendous health risks. Testing processes proved that there is an exact match between empirical testes and typical results of (Freundlich and Langmuir) models, through the mathematical analysis of the trial data under different thermal conditions, all testes proved that (husks of sunflower) is the best hypertext filtered materials for its high adsorption efficiency which equal to (71%) with enthalpy equal to (33KJ/mol), followed in the second place (peel peanuts), these peels proved have an excellent efficiency which equal to (72%) with enthalpy equal to (-14.8KJ/mol). In general, food remnants which have been selected for testing on an ion adsorption system designed by researcher have high capacity to adsorb various ionic roots of industrial water of Al-Musayab thermal station

The scrap tires considered a problematic source of waste, the old rubber tires causes a big environmental problem that is need much money and effort to disposes it safely. In Iraq there are more than two million used tires disposed to the environment annually. one of the tire’s recycling methods is the use of tire layers to produce a new rubber parts used in the engineering and industrial purposes as the bridges and machines dampers, this trend of recycling doesn’t take a sufficient care comparing with the other uses. There are a lot of studies conducted in these field, these studies suggests many methods to manage the huge number of scrap tires, the current paper aims to use the old rubber tires in engineering purposes (especially as a coupler joins the motor or engines with the other equipment as electric dynamo or pumps), the study focusing on the mechanical properties of a strip from a used tires and comparing with one prepared in the lab., and suggesting a new method to use as an engineering parts (for example the coupler lays between the IC engine and the dynamo of an electric generator). One of the results obtained from the experiments, there is no significant difference between the mechanical properties of the old and the new strip, (in the tensile test, the breaking force of the -Lab. tensile specimen- is 137 N whereas the specimen of old tire have a breaking force 113.27 N, but they are same in the elongation). A computational example is suggested to estimate the dimensions of a flexible coupler use an old tire pieces

Gray cast iron has many applications as pipes, pumps and valve bodies where it has influenced by heat and contact with other solutions . This research has studied the corrosion behavior and Vickers hardness of gray cast iron by immersion in four strong alkaline solutions (NaOH, KOH, Ca(OH)2, LiOH)with three concentrations (1%,2%,3%) of each solution. Dry sliding wear has carried out before and after the heat treatments (stress relief, normalizing, hardening and tempering). In this work, maximum wear strength has obtained at tempered gray cast iron and minimum corrosion rate has obtained in LiOH solution by forming protective white visible oxide layer.

Cuprous oxide (Cu2O) has been formed on glass substrates by dc reactive magnetron sputtering method, whereas pure target of the solid copper was sputtered with a mixture of plasma for argon gas and oxygen gas was used to form these films. Under vacuum chamber pressure of 1.2×10-5 Pa, thin film thickness was changed from 100 nm to 300 nm while other deposition parameters were fixed. The influence of changing the thickness of thin films on the electrical and the optical properties was investigated in this study. X-ray photoelectron spectroscopy (XPS), X-ray Diffractions system XRD, Atomic Force Microscopy (AFM), hall effect measurement system, UV–VIS spectrophotometer were employed to determine the characteristic of the deposited thin films. Thin film of 200 nm has observed low resistivity of 60.63 Ω cm and direct band gap of 2.5eV. This study has demonstrated that the thickness has direct influence on electrical and optical properties

In this research, Iraqi bauxite was used as raw material, after preparation the producing a grog. The mix proportion was applied, (96:4), (93:7) and (90:10) as (bauxite grog: kaolin binding ), and the sodium silicate solution as adhesive material 5% by weight of the mix.The burning temperatures for specimens' producing were 1450ᵒC. The physical investigation was carried such as (bulk density, specific gravity, apparent of porosity and water absorption). While the mechanical tests (compressive, bonding) strength, durability investigations such as (thermal shrinkage, reheating expansion and thermal shock). It was found the third group recorded the highest compression and bonding strength and thermal shock resistance and the best physical properties after burning at 1450 ºC, with mix proportion (90: 10).

Coarse grains of soil particles play an important role in the geotechnical problems. Therefore, it is necessary to predict of CBR value from some physical properties that easy, low time consume, and limited facility for laboratory experiments. In this paper, an attempt has been conducted to correlate CBR value of coarse-grained soils based on some physical properties such as grain size analysis (percentage finer sieves 25, 9.5, 4.75, 2.36, 1.18, 0.3, and 0.075mm), particles fraction as Gravel (G), Sand (S), and Fines (F). Other parameters taken into consideration are Compaction Characteristics namely optimum moisture content (OMC) and maximum dry density (MDD). The tests conducted for determining grain size, MDD and OMC are easy cheaper and less time to consume than soaking CBR test. The correlation established was in the form of an equation of soaked CBR value as a function of different soil properties using regression analysis.

In this research, aimed to study the behavior of simply supported steel concrete composite beams with normal and high compressive strength of the concrete slab under the action of a span mid-point external load. The steel I-section beam is located at the bottom of reinforced concrete slab and connected with it by stud shear connectors. Eight composite beams were tested under the action of a monotonic load, half of them had a normal strength concrete slab while the others with a high strength concrete slab. Four degrees of shear connection interaction (100%, 80%, 60%, and 40%) were used for both groups of the tested beams. It was noticed that there are no essential differences between the modes of failure that occurred in the tested beams with normal strength concrete and those with high strength concrete. It was also found that there is an increase in the initial stiffness of the beams when the concrete changed from normal to high strength for different degrees of shear connections, but this increment reduced with increasing the degree of the shear connection. It was noted that the ultimate capacity of the tested beams was increased with enhancement of the strength of the adopted concrete from normal to high strength. The results showed that, when the concrete compressive strength was increased from 32.6 MPa to 72.8 MPa, the ultimate moment capacity of the specimens was increased from 28% for 100% shear connection, and it is increased to 38% for specimens with 40% shear connection.

Remanufacturing is a powerful tool for developing ecological approach for many application Degrade honeycomb sheets for architectural use in construction are broadly used for ceiling, cladding and interiors applications End-of-life vehicle steel sections are used as cores to produce honeycomb steel where there are only three sections can be used such sections are attributed in the final products liability and quality. Remanufacturing of steel sections Remanufacturing of end of life steel vehicles sections in to honeycomb cores is targeting to reduce power ,material and fossil carbon emissions of end of life steel vehicles frame is studied and disassembled to classify the suitable parts for Remanufacturing the cores for steel honeycomb steel also thin steel sheets are used to covers. Remanufacturing and testing routes are figured and .Mechanical properties are tested and registered to be used for performance study end of life vehicle sections can be successfully degraded in to honeycomb cores to substitute current consumption of materials. Mechanical properties can be developed to match construction application standards by exploiting of sustainable assembling technology by using screens .As a conclusion reliable steel honeycomb can be matured by exploiting in remanufacturing technology and assembly techniques end –of- life sections can contribute to reduce power, materials consumption and carbon emissions.

A paper focuses on the investigation ofthe stress-strain for E-glass fiber /polyester composite plates subjected to the uniform temperature at various factors, such as fiber volume fraction and fiber orientation. To study the stress analysis of composite plate two methods are used: The First method is an experimental test by applying a uniform temperature on the composite plate inside the furnace and a measure the deformation of the plate by using dial gage. The second method based on a finite element solution using ANSYS (ver. 15) program. The results presented here that, the maximum strain in longitudinal direction occurs at a ply angle (90º), whereas the minimum value at a ply angle (0º). However, the maximum strain in transverse direction occurs at a ply angle (0º) whereas the minimum value at a ply angle (90º). In general, the magnitude of thermal strain increases with increasing temperature difference (∆T) and decreases with increasing the fiber volume fraction ( Comparison the results of the experimental test with the numerical analysis of the thermal strain and evaluated the agreement between the two methods used, the maximum discrepancywas 19.7%.

Expansive soils are characterized by their considerable volumetric deformations representing a serious challenge for the stability of the engineering structures such as foundations. Consequently, the measurements of swelling properties, involving swelling and swell pressure, become extremely important in spite of their determination needs a lot of time with costly particular equipment. Thus, serious researches attempts have been tried to remedy such soils by means of additives such as cement, lime, steel fibers, stone dust, fly ash and silica fume. In this research the study of silica fume has studied to treatment expansion soil, the clay soil was brought from Al-Nahrawan in Baghdad. The soil selected for the present investigation prepared in laboratory by mixing natural soil with different percentages of bentonite (30, 50 and 70% by soil dry weight). The test program included the effect of bentonite on natural soil then study the effect of silica fume (SF) on prepared soil by adding different percentage of silica fume (3, 5, and 7 by weight) to the prepared soils and the influence of these admixtures was observed by comparing their results with those of untreated soils (prepared soils). The results show that both liquid limit and plasticity index decreased with the addition of silica fume, while the plastic limit is increase with its addition. As well as, a decrease in the maximum dry unit weight with an increase in the optimum water contents have been obtained with increasing the percentage of addition of the silica fume. It is also observed an improvement in the free swell, swelling pressure by using silica fume. It can be concluded that the silica fume stabilization may be used as a successful way for the treatment of expansive clay.