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Experimental study on thermo‐hydraulic performance of metal foam twisted tape in a double pipe heat exchanger
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Abstract<p>A recent study compared experimentally the hydraulic and thermal activity of twisted tape inserts for two types, metal foam twisted tape (MFTT) and traditional twisted tape (TTT), in a double pipe heat exchanger. The investigation goal of the innovatively designed MFTT is to enhance the heat transfer process, which provides a higher thermal enhancement factor over those of TTT under the same conditions. Heat transfer activity in terms of Nusselt number (<italic>Nu</italic>) and Nusselt number ratio (<italic>Nu</italic>/<italic>Nu</italic><sub>o</sub>) as the heat exchanger equipped with the proposed MFTT and TTT inserts with various tape‐twist ratios (<italic>y</italic>/<italic>W</italic> = 3.6, 5.2, and 6.8) are considered over various values of Reynolds numbers (16,300 < <italic>Re</italic> < 32,500). The results reveal an improvement in heat transfer rate with both MFTT and TTT and this improvement is proportional inversely to the twisted ratio, but the MFTT showed the highest value of heat transfer compared to TTT and clear tube. Also, the <italic>Nu</italic> of MFTT augments averaged about 175%–230% compared to the TTT depending on the twist ratio and about 275% and 500% over that of the clear tube. At a twist ratio of 3.6, the heat transfer coefficient is recorded at 37% and 45% for MFTT and TTT models, respectively, with an increase in Re. However, friction factor (<italic>f</italic>) increases about 35% for MFTT with decreasing in twist ratio (from 6.8 to 3.6). The effectiveness of the proposed MFTT in the range of <italic>Re</italic> used is found to be about 12%, 15%, and 18% higher than those induced by TTT at twisted tape ratio (<italic>y</italic>/<italic>w</italic> = 3.6, 5.2, and 6.8), respectively.</p>
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Publication Date
Thu Dec 10 2009
Journal Name
Iraqi Journal Of Laser
Bactericidal effect of Q-switched Nd:YAG laser (1064 nm ) on Streptococcus mutans from carious teeth ,in vitro study
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Dental caries (tooth decay) is one of the most prevalent infectious disease and although of multifactorial origin, Streptococcus mutans is considered the principal pathogen in its development (i.e. bacterial processes damage hard tooth structure (enamel, dentine and cementum), producing dental cavities (holes in the teeth). The bactericidal properties of the Nd:YAG laser has been researched analyzing its use in caries prevention and bacterial reduction. One hundred twenty five samples were collected from carious teeth and isolated bacteria were diagnosed using microscopic examination, culture, biochemical tests, and Api 20 strep system. The results of this study showed that a noticeable decrease in the viability of Streptococcus mutans w

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Publication Date
Sat Aug 23 2025
Journal Name
Journal Of Physical Education
Consecutive Case Study of Detraining On Some Functional, Physical, Body and Compound Skills Variables In Advance Basketball Players
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Publication Date
Mon Dec 03 2018
Journal Name
Journal Of Engineering
The Effect of Urban Land Use Changing on Green Area Neighborhoods No. 336 & 338 in Baghdad – Case Study
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The role of the green areas lies in being one of the systems that plays the vital role in achieving the environmental dimension besides the socio-cultural body and the economic dimension in the hidden value of ecosystem services. However, many developing countries are characterized by a state of low community environmental awareness, which coincides with the basic need for land for housing and other uses, to take precedence over nature protection strategies. In the absence of clear planning and long-term planning strategies, all this led to abuses and violations of urban land use. In Iraq, the situation became more apparent due to the political, security and social conditions that followed the year 2003. Hence, the resea

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Publication Date
Sun Sep 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Sharing knowledge on organizational innovation Field study in the arab company , for detergents and chemical
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ABSTRACT

Impkact  of  Knowledge  sharing  on  organizational  innovation  Impriscal  study in Arabic company . 

of  Knowledge Management is  the  main  component  Knowledge  sharing  system, it mean the exchange if  Knowledge, ideas, and good  practice with  another  individual . Knowledge sharing between persons, then its values can growth .

It is vry important because it can provide us with the contention between virus peoples . the interaction among the people can pass all kind of Knowledge among them. the connection and interaction and interaction enabl

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Publication Date
Sat Aug 23 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of ER: YAG laser on enamel resistance to caries during orthodontic treatment: An in vitro study
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Background: One common undesirable side effect of orthodontic treatment with fixed appliances is the development of incipient caries lesions around brackets, particularly in patients with poor oral hygiene. Different methods have been used to prevent demineralization; the recent effort to improve the resistance against the demineralization is by the application of lasers. Materials and method: Thirty human premolars extracted for orthodontic purposes were used to test the effect of two energy level of ER-YAG laser on enamel resistance to demineralization. The brackets were bonded on the teeth and all the labial surface excluding 2 mm area gingival to the brackets were painted with acid resistance varnish. Three groups were generated. The fi

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
Theoretical Study of The Heating Effect of Laser Radiations on SiUcaGlass Systems
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A theoretical study has been proposed to investigate the effects of different laser radiations (Nd - glass, DF and C02) as a heating source on different glass samples (Optical glass, Bk - 7 and Soda - lime glass) and different waves lengths (10.6, 3.8, 1.6) ???. The heat changes as which are resulted due irradiation with laser sources have been determined by using the one dimension mathematical relation as a function of time (t) and depth (z). The results of the study show ed that the irradiation with C02 laser had a greater effect than DF laser, while the effects of Nd - glass laser were minimal with a power density of (1.8*10?? w/m2) within atime(l^sec).(Forboth Kinds) The change in the temperatures were not exceeded than (70"K) in all sa

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Publication Date
Sat Jan 05 2019
Journal Name
Iraqi Journal Of Physics
Study the effect of CaCO3 nanoparticles on physical properties of biopolymer blend
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Chitosan (CH) / Poly (1-vinylpyrrolidone-co-vinyl acetate) (PVP-co-VAc) blend (1:1) and nanocomposites reinforced with CaCO3 nanoparticles were prepared by solution casting method. FTIR analysis, tensile strength, Elongation, Young modulus, Thermal conductivity, water absorption and Antibacterial properties were studied for blend and nanocomposites. The tensile results show that the tensile strength and Young’s modulus of the nanocomposites were enhanced compared with polymer blend [CH/(PVP-co-VAc)] film. The mechanical properties of the polymer blend were improved by the addition of CaCO3 with significant increases in Young’s modulus (from 1787 MPa to ~7238 MPa) and tensile strength (from 47.87 MPa to 79.75 MPa). Strong interfacial

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Publication Date
Sun Jul 01 2018
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
STUDY ON DIVERSITY OF BEES (HYMENOPTERA, APOIDEA) FROM DIFFERENT REGIONS OF IRAQ
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    The fauna of bees (Hymenoptera, Apoidea) from different regions of Iraq is surveyed in this study; there were 16 species, 13 genera that belong to four families which are collected in this investigation.

 

    Also, all the species that are recorded for Iraq in previous investigations are revised; totally there are 110 species, 32 genera belonging to  five families: Apidae, Andernidae, Colletidae, Halictidae and Megachilidae were listed.

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Publication Date
Mon Jan 01 2018
Journal Name
Aip Conference Proceedings
Study the effect of nano SiO2 on dielectric strength property of zirconia
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Publication Date
Mon Jan 01 2018
Journal Name
Aip Conference Proceedings
Study the effect of nano SiO2 on dielectric strength property of zirconia
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