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Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh number and number of foam fins in the axial direction, on fluid flow and heat transfer characteristics, were examined. The current model was valid with the available published results and good agreement is noticed. Results showed that as the Rayleigh number increases the dominated of convection mode increases and average Nusselt increases. It was found that at Rayleigh of 106 Nusselt reached its higher value which is 4.6 for the case of adding seven axial metal foams. A comparison between adding foam fins and copper fins was established for a range of Rayleigh numbers between 104 and 106. It showed a good enhancement in Nusselt number and the greatest enhancement percentage was 45.9% at Rayleigh equal 106 for the case of using seven sections of foam fins. |
Objective: the aim of this study is to invest age and determine the effect of using (2) packing
technique (conventional and new tension technique) on hardness of (2) types of heat cure acrylic
resin which are (Ivoclar and Qual dental type).
Methodology : this study was intended the using of two types of heat cure acrylic (IVoclar and
Qual dental type) which are used in construction of complete denture which packed in two different
packing technique (conventional and new tension technique) and accomplished by using a total of
(40) specimens in diameter of ( 2mm thickness, 2 cm length and 1 cm width) . This specimens were
sectioned and subdivide into (4) group each (10) specimens for one group , then signed as (A, Al B
The aim of this work is the synthesis of new grafted PVA polymer with a derivative of Erythro-ascorbic acid (pentulosono-ɣ -lactone-2, 3-enedianisoate). All synthesized compounds were characterized by thin layer chromatography (TLC) and FTIR spectra and aldehyde was also characterized by (U.V-Vis), 1HNMR, 13CNMR and mass spectra. They were also evaluated for antimicrobial properties by dilute method against four pathogenic bacteria (Escherichia coli ,Klebsiella pneumonae, Staphylococcus aureus, Staphylococcus Albus) and two fungal (Aspergillus Niger, Yeast). All polymer metal complexes showed good activities against the various microbial isolates. The polymer metal complexes showed higher activity than the free polymer. The order of increa
... Show MoreAzo-ligand-(HL) ([4- ((2-hydroxyquinolin-3-yl) diazenyl) -N- (5-methylisoxazol-3yl) benzenesulfonamide]), (2- hydroxy quinolin derivative),reacts with the next metal ions (Cr (III), Fe (III),Co (II) and Cu(II)) forming stable complexes with unique geometries such as(tetrahedral for bothCo (II) and Cu (II), octahedral for both Cr (III) and Fe (III)). The creation of such complexes was detected by employing spectroscopic means involving ultraviolet-visible which proved the obtained geometries, Fourier transfer proved the involvement of coordinated water molecule in all complexes besides the pyrolysis (TGA & DSC) studies proved the coordination of water residues with metal ions inside the coordination sphere as well as chlorine atoms. Moreover
... Show MoreFind cares studying the aesthetics of environmental art, one of the topics that is one of the problems of the aesthetic side in the arts of postmodernism, so this research came as an attempt to get to know the aesthetic concepts of environmental art that can be learned from functional testing in the formation of the post-modern control. The research involved four chapters: The first chapter discusses the general framework of the research methodology, as it was displayed in itThe research problem and its importance and define its objective to identify the aesthetics of environmental art at the level of the body, meaning, the receiver .ozlk in Iraq and America as the spatial limits of the time limits are period stretching from 1970 to 2006
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Background: Drawing blood to measure total serum bilirubin is painful & time consuming. Transcutaneous bilirubinometer working by multiwavelength spectral reflectance from the skin surface on forehead or upper sternum is a quick & painless technique. Objectives: to compare the effectiveness of transcutaneous (over the upper sternum and forehead) and serum bilirubin measurement of neonate with jaundice. Subjects and Methods: This is a cross sectional prospective study. It enrolled 175 jaundiced neonates & excluded those exposed to phototherapy. It was conducted at Child Central Teaching Hospi |
Through this research, We have tried to evaluate the health programs and their effectiveness in improving the health situation through a study of the health institutions reality in Baghdad to identify the main reasons that affect the increase in maternal mortality by using two regression models, "Poisson's Regression Model" and "Hierarchical Poisson's Regression Model". And the study of that indicator (deaths) was through a comparison between the estimation methods of the used models. The "Maximum Likelihood" method was used to estimate the "Poisson's Regression Model"; whereas the "Full Maximum Likelihood" method were used for the "Hierarchical Poisson's Regression Model
... Show MoreTo decrease the impact on the environment of building waste, the recycled aggregate may be used in various sustainable engineering applications, such as roller compacted concrete pavement (RCCP). This research examined how using recycled aggregate as a partial replacement for natural aggregate as coarse or fine affected the mechanical properties of roller-compacted concrete pavement. The recycled aggregate was crushed and sieved to coarse and fine aggregate before being used in the roller-compacted concrete pavement. Compressive strength, splitting tensile strength, and flexural strength were all evaluated after the samples were prepared at 28 and 90 days of curing. According to the study's findings, the partial replacem
... Show MoreThis experiment presented essential oils by GC/MS, pigment content, and their antioxidant activities as well as sensory evaluation of delight samples. Limonene (66.88%) was the most prevalent yield. The peels of clementine had DPPH and ABT Scavenging activity. All levels of pigment extract had better scores for all sensory values and recorded acceptable scores in terms of appearance, color, aroma, and overall acceptability compared to control delight. Besides, delight samples containing 15 mg astaxanthin pigment extract showed maximum sensory scores compared to other samples and control delight. On the other hand, the product was less acceptable to the panelists compared to control in the case of the addition of 3.75 mg astaxanthin pigme
... Show MoreThe aim of this study is to make the inventory for Umbelliferae family for the purpose of identifying the samples that were collected over long periods and saved in the herbarium of Iraq Natural History Museum/ University of Baghdad. We found that the herbarium plants were very large and varied from different parts for Iraq, in different and varied environments, which collected and arranged according to a very specific system in the herbarium for remaining an important source to all graduate students and researchers to take advantage for these plants. Also, the flowering and fruiting periods for these plants in Iraq were recorded in different regions. Most these plants begin to flower in the spring and thrive at fields and farms.
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