In this study, a different design of passive air Solar Chimney(SC)was tested by installing it in the south wall of insulated test room in Baghdad city. The SC was designed from vertical and inclined parts connected serially together, the vertical SC (first part) has a single pass and Thermal Energy Storage Box Collector (TESB (refined paraffin wax as Phase Change Material(PCM)-Copper Foam Matrix(CFM))), while the inclined SC was designed in single pass, double passes and double pass with TESB (semi refined paraffin wax with copper foam matrix) with selective working angle ((30o, 45o and 60o). A computational model was employed and solved by Finite Volume Method (FVM) to simulate the air induced through the test room by SC effect. The governing equation of Computational Fluid Dynamic (CFD) model was developed by the effective heat capacity method equation to describe the heat storage and release from PCM-CFM. Practical and computational Results referred to increase in thermal conductivity of the paraffin wax that supported by CFM than 10 times, while the ventilation effect is still active for hours after sun set amount. The maximum ventilation mass flow rate with TESB collector was 36.651 kg/hr., when the overall discharge coefficient equals 0.371. Also, the experimental results referred to the best working angle range 45~60o, while the highest approaching temperature (between air and collector) was appeared for the double passes flat plate collector. Results gave higher heat storage efficiency 47% when the maximum solar radiation 780 W/m2 at 12.00 pm, and the energy summation through duration of charging time was 18460 kJ. Double passes SC at 60o angle presented the highest efficiency with value approaching to 73%, while TESB collector efficiency depicted highest efficiency value 70% at 12:00 pm.
The research was conducted in one of the fields of the Department of Plant Production in the desert region (tomato development project) affiliated with the Directorate of Agriculture of the Holy Karbala Governorate for the purpose of studying the effect of spraying the shoots of the Kohlrabi plant (hybrid) with the Nano biopolymer (Chitosan) and the Azotobacter bio inoculum on the roots of the plant seedlings in terms of growth indicators and yield for the autumn agricultural season. 2023-2024 ,The means were compared according to the Duncan multiple ranges test at significant to level of 0.05.with R.C.B.D . The first factor was spraying the shoots with Nano- Chitosan at a concentration of (0, 1, and 2) g L-1, two weeks after transplanting,
... Show More
This article investigates the development of the following material properties of concrete with time: compressive strength, tensile strength, modulus of elasticity, and fracture energy. These properties were determined at seven different hydration ages (18 h, 30 h, 48 h, 72 h, 7 days, 14 days, 28 days) for four pure cement concrete mixes totaling 336 specimens tested throughout the study. Experimental data obtained were used to assess the relationship of the above properties with the concrete compressive strength and how these relationships are affected with age. Further, this study investigates prediction models available in literature and recommendations are made for models that are found suitable for application to early age conc
... Show MorePolyvinyl alcohol, (PVA) was prepared using polyvinyl acetate emulsion (manufactured by Al-Jihad factory,
That-Al-Sawary Company) as a local raw material. In this investigation, polyvinyl acetate emulsion was converted to
solid form by coagulation the polymer from its emulsion using sodium sulphate salt as coagulant aid, then alcoholyzed
the solid polyvinyl acetate in methanol using sodium hydroxide as catalyst, polyvinyl alcohol produced by this method is
a dry, white to yellow powder.
Three affecting variables on the degree of hydrolysis of PVA were studied, these variable are Catalyst to
polymer weight ratio in the range of 0.01 – 0.06, reaction time in the range of 20 – 90 min, and reaction temperature in
the
Drilling fluid loss during drilling operation is undesirable, expensive and potentially hazardous problem.
Nasiriyah oil field is one of the Iraqi oil field that suffer from lost circulation problem. It is known that Dammam, um-Radoma, Tayarat, Shiranish and Hartha are the detecting layers of loss circulation problem. Different type of loss circulation materials (LCMs) ranging from granular, flakes and fibrous were used previously to treat this problem.
This study presents the application of rice as a lost circulation material that used to mitigate and stop the loss problem when partial or total losses occurred.
The experim
... Show MoreAn experimental study was carried out for an evaporative cooling system in order to investigate the effect of using an aluminum pad coated with fabric polyester. In the present work, it was considered to use a new different type of cooling medium and test its performance during the change in the wet-bulb temperature and dry-bulb temperature of the supply air outside of the pad, the relative humidity of the supply air, the amount of air supplied (300-600) CFM and also the change of the amount of circulated water (1.75, 2.5, 4.5) liter per minute. A decrease in the WBT of the air was obtained, whereas the WBT of the air entering the pad was 26.5 . In contrast, the WBT of the outside air had reached 23 even though eva
... Show MoreThe present work is devoted to investigate the performance of a homemade Y-shape catalytic microreactor for degradation of dibenzothiophene (DBT), as a model of sulphur compounds including in gas oil, utilizing solar incident energy. The microchannel was coated with TiO2 nanoparticles which were used as a photocatalyst. Performance of the microreactor was investigated using different conditions (e.g., DBT concentration, LHSV, operating temperature, and (H2O2/DBT) ratio). Our experiments show that, in the absence of UV light, no reaction takes place. The results revealed that outlet concentration of DBT decreases as the mean residence time in the microreactor increases. Also, it was noted that operating temperature s
... Show MoreDifferent parameters of double pipe helical coil were investigation experimentally. Four coils were used; three with a curvature ratio (0.037, 0.031, and 0.028) and 11mm diameter of the inner tube while the fourth with 0.033 curvature ratio and 13 mm diameter of the inner tube. The hot water flow in the inner tube whereas the cold water flows in the annulus. The inlet temperatures of hot and cold water are 50 0C and 18 0C respectively. The inner mass flow rate ranges from 0.0167 to 0.0583 kg/s. The results show the Nusselt number increase with increase curvature ratio. The Nusselt number of the coil with 0.037 curvature ratio increases by approximately 12.3 % as compare with 0.028 curvature ratio. The results also r
... Show MoreContinuous escalation of the cost of generating energy is preceded by the fact of scary depletion of the energy reserve of the fossil fuels and pollution of the environment as developed and developing countries burn these fuels. To meet the challenge of the impending energy crisis, renewable energy has been growing rapidly in the last decade. Among the renewable energy sources, solar energy is the most extensively available energy, has the least effect on the environment, and is very efficient in terms of energy conversion. Thus, solar energy has become one of the preferred sources of renewable energy. Flat-plate solar collectors are one of the extensively-used and well-known types of solar collectors. However, the effectiveness of the coll
... Show MoreThe largest use of x-ray in medical by dentists, employers or persons that needed by patients with specific conditions, lead to higher exposure of x-ray that may cause many diseases. In the present work radiography films have been used in evaluating the efficiency of using unsaturated polyester polymer reinforced with lead oxide (PbO) as shield material for medical x-ray devices, many parameters studied like concentration and thickness that they are increasing the attenuation of x-ray in them. The results show that the attenuation of X-ray increasing with concentration of reinforced material and with thickness, and the optical density decreases with increasing concentration from 0% to 50%, we chose 30% as suitable concentration to increase
... Show More