This study examines experimentally the performance of a horizontal triple concentric tube heat exchanger TCTHE made of copper metal using water as cooling fluid and oil-40 as hot fluid. Hot fluid enters the inner annular tube of the TCTHE in a direction at a temperature of 50, 60 and 70 oC and a flow rate of 20 l/hr. On the other hand, the cooling fluid enters the inner tube and the outer annular tube in the reverse direction (counter current flow) at a temperature of 25 oC and flow rates of 10, 15, 20, 25, 30 and 35 l/hr. The TCTHE is composed of three copper tubes with outer diameters of 34.925 mm, 22.25 mm, and 9.525 mm, and thicknesses of 1.27 mm, 1.143 mm, and 0.762 mm, respectively. TCTHE tube's length was 670 mm. Nusselt number, overall heat transfer coefficient, convective heat transfer coefficient (CHTC), friction factor and pressure drop were measured from the obtained experimental results and plotted in graphs against Reynold number and volumetric flow rate of water. These parameters appeared good results in the cooling process. Nusselt numbers increased linearly with DIW flow rate for both C1 and C2 reaching maximum values of 38.25 and 14.64 respectively. CHTC increased linearly with the DIW flow rate for both C1 and C2 reaching maximum values of 2934.3 and 871.7 respectively. Overall heat transfer coefficient of DIW reached maximum values of 296.36 and 251.4 at 35 l/hr for C1 and C2, respectively. Friction factor DIW in C1 and C2 decreased with the volumetric flow rate increases, reaching minimum values of 0.04 and 0.25 respectively. Pressure drop of DIW increased linearly with flow rate reaching maximum values of 81.4 and 4.31 for C1 and C2 respectively. This in turn leads to reduced TCTHE length and size leading to a decrease in the construction cost of the heat exchanger.
The current Iraqi standard specifications for roads and bridges allowed the prepared Job-Mix Formula for asphalt mixtures to witness some tolerances with regard to the following: coarse aggregate gradation by ± 6.0 %, fine aggregate gradation by ± 4.0 %, filler gradation by ± 2.0 %, asphalt cement content by ± 0.3 % and mixing temperature by ± 15 oC. The objective of this work is to evaluate the behavior of asphalt mixtures prepared by different aggregates gradations (12.5 mm nominal maximum size) that fabricated by several asphalt contents (40-50 grade) and various mixing temperature. All the tolerances specified in the specifications are taken into account, furthermore, the zones beyond these tolerances
... Show MorePapillary thyroid carcinoma (PTC) represents the most prevalent kind of thyroid gland cancer, making up around 80% of all occurrences of thyroid cancer. Evidence shows that Syndecan-1 (SDC-1) expression is lost in a number of benign and malignant epithelial neoplasms, although its expression profile in thyroid gland neoplasms is yet unknown. Therefore, the aim of this study was to assess SDC-1 expression in papillary thyroid carcinoma patients, as well as the relationship between age and gender and SDC-1 expression. To undertake a detailed investigation of SDC-1 in normal and malignant tissues, tissue sections were used to examine SDC-1 expression in 70 tissue samples, 50 distinct PTC (6 males and 44 females) and 20 normal tissue ty
... Show MoreThe distress of moisture induced damage in flexible pavement received tremendous attention over the past decades. The harmful effects of this distress expand the deterioration of other known distresses such as rutting and fatigue cracking. This paper focused on the efficiency of using the waste material of demolished concrete to prepare asphalt mixtures that can withstand the effect of moisture in the pavement. For this purpose, different percentages of waste demolished concrete (0, 10, 20, 30, 50, 70 and 100) were embedded as a replacement for coarse aggregate to construct the base course. The optimum asphalt contents were determined depending on the Marshall method. Then after, two parameters were founded to evaluate the moisture
... Show MoreThis study has evaluated the humoral immune response in Golden Hamsters experimentally infected with Leishmania donovani along (4) times of follow up (15, 30, 60, 90) days after infection. Indirect haemagglutination test was used to determine the antibody titer through the various stages of the study. Also the progress of the infection was studied depending on some of the visceral changes caused by the parasite, like weight of liver, length & weight of spleen & the count of Leishmania parasites in spleen were measured. Results has shown that there was an increase in antibody titer & the maximum value was recorded at the 4th day of follow up (90 days after infection) as well as that there was an increase in the length of the spleen, weight
... Show MoreI found that it does not meet some of the requirements, including browsing and organizing structural elements, which is something in which the researcher found a scope for research, and from here she can formulate the problem of her research with the following question: Is there an actual need to develop user interface designs in the websites of Iraqi colleges of fine arts? The research included four chapters (the first chapter - the research problem - the second chapter (theoretical framework), which included three sections, the first is to identify the user interface, the second topic is the structural elements, and the third topic includes the rules of interface design and the dimensions of interaction), as well as the third chapter i
... Show MoreObjectives: to assess the normal range of different lip parameters with gender difference and its role in esthetic procedures for Iraqi people. Methods: direct lip measurements were performed with closed lip position using a digital vernier caliper in 132 young Iraqi subjects (89 female and 43 male). Results: Lip measurements showed sexual dimorphism with higher value in men than women in six parameters. Cutaneous height of the upper lip was higher in both sexes. The mustache area in males was longer in males compared to females. Also, it was noticed that upper lip vertical thickness had a higher value, especially in subjects with cosmetic procedures. In addition to that, vertical upper lip thickness showed a higher rise in values
... Show MoreBackground: Leishmaniasis is important public
health problem owing to its impact on morbidity
and mortality and difficulties in application of
effective control measures.
Objective: The aim of the study is to evaluate the
using of impregnate bed nets in the control of
leishmaniasis.
Methods: The study was conducted throughout
the years 2004 and 2005, in Diala Governorate
(about 60km north-east Baghdad). This is the first
study in Iraq for evaluation of the impregnated bed
net in control of leishmaniasis. Two villages were
selected to achieve this aim. The nets were
distributed for the first village to be used by their
population. The second village was served as
control.
Results: The
... Show MoreThis study aims to suggest an alternative to the use of quality agricultural soil in the brick industry (Iraq). The Late Miocene claystone bed in the Injana Formation in central Iraq was targeted through the study of 18 exposed sections that were sampled by using the trench sampling method. The claystones are characterized by quartz (36.4%) followed by calcite (32.8%), quartz (36.4%) feldspar (2.6%), gypsum (1.3%) and dolomite (0.7%), kaolinite (10.5%), illite (7.7%), chlorite (6.7%), palygorskite (6.0%) and montmorillonite (0.7%). New thermal mineral phases were formed at 950°C, including diopside (62.9%), quartz (18.4%), wollastonite (8.28%), akermanite (7.6%), Anorthite (6.25%), Nosean (4.9%), gehlenite (3.75%) and Lazurite (3.1
... Show More