The present work presents a new experimental study of the enhancement of turbulent
convection heat transfer inside tubes for combined thermal and hydrodynamic entry length of one
popular “turbulator” (twisted tape with width slightly less than internal tube diameter) inserted for
fire tube boilers. Cylindrical combustion chamber was used to burn (1.6 to 7kg/h) fuel oil #2 to
deliver hot gases with ranges of Reynolds number (10500 to 21700), and (11400 to 24150) for both
empty and inserted tube respectively.A uniform wall temperature technique was used by keeping
approximately constant water temperature difference (25ºC) between inlet and exit cooling water in
parallel flow shell and tube heat exchanger. The test tube consisted of smooth carbon steel tube of
(2400mm) long and (52mm) internal diameter. This test tube instrumented to derive local heat
transfer coefficient and local flue gasses static pressure.The experimental results show that for the
same fuel consumption, twisted tape insert with (H/D = 11.15) enhanced the mean Nusselt number
in (75.2%), (68.8%), (49.8%), (40.3%), and (16.7%) for fuel consumption (7kg/h), (6.16kg/h),
(4.5kg/h), (3.24kg/h), and (1.6kg/h) respectively.A set of empirical correlations that permit the
evaluation of the mean Nusselt number (for developing and fully developed region), and average
Nusselt number (for developed region) for empty and inserted tube are generated for engineering
applications.
In recent decades, tremendous success has been achieved in the advancement of chemical admixtures for Portland cement concrete. Most efforts have concentrated on improving the properties of concrete and studying the factors that influence on these properties. Since the compressive strength is considered a valuable property and is invariably a vital element of the structural design, especially high early strength development which can be provide more benefits in concrete production, such as reducing construction time and labor and saving the formwork and energy. As a matter of fact, it is influenced as a most properties of concrete by several factors including water-cement ratio, cement type and curing methods employed.
Because of acce
This study has been conducted to examin the effect of sodium propionate at different level of 0.03,0.06,0.10% on the number of bacteria and mold and to extend the storage life of laboratory processed biscuit. The results indicated that the use of 0.10% sodium propionate prolonged the storage peroid until the third month, while the use of 0.20% sodium propionate showed no growth of bacteria up to six month of storage, three types of bacteria has been isolated from processed biscuit, namely, Staphylococcus aureus, Bacillus cereus, Esherichia coli. using 0.10% sodium propionate showed no growth of mold up to three month of storage ,while using of 0.15 % and 0.20% sodium propionate prevent the growth
... Show MoreThis research is considered as the beginning of other studies about the iraqi the public and their relationship with the various state institutions. Recently, such studies used to be almost non-existent. The main characteristic that distinguishes the scientific studies, is the fact that it involves a specific problem that needs to be studied and analysed from multiple aspects, otherwise the definition of problem identification wouldn’t have been narrowing the topic into what the researcher wants to address, also not what the title is referring to as topics which the researcher doesn’t want to address. The problem in this research resides in the lack of well planned scientific programs that aims at building a positive mental picture a
... Show MoreOur goal in this research, some new nucleoside analogues was synthesized. Starting from ?-D glucose which was converted to per acetylated ?-D gluco pyronoside then converted to active from(1-Bromo Sugar (2) as a sugar moiety.The base moiety 2-substituted benzimidazole was prepared from condensation of phenylene diamine with different aromatic aldehydes, which were subjected to amino alkylation via Mannich reaction forming new nucleobase derivatives. Condensation of nucleobase with bromo sugar through nucleophilic substitution of anomeric carbon with nitrogen forming new protected nucleoside analogues then hydrolyzed with sodium methoxide in methanol to obtain our target, the free nucleoside analogues. All prepared compound were identified b
... Show MoreObjective(s): To evaluate students’ communication skills and their academic performance; to compare between the students relative to communication skills and their academic performance in the University of Baghdad and to identify the relationship between students’ communication skills, academic performance and their socio-demographic characteristics of age, gender, grade and socioeconomic status. Methodology: A descriptive design, using the evaluation approach, is carried through the present study to evaluate colleges’ students’ communication skills and their academic performance in the University of Baghdad for the period of January 7th 2019 to August 28th 2019. A non-probability, purposive sample, of (80) university students, i
... Show MoreNiO0.99Cu0.01 films have been deposited using thermal evaporation
technique on glass substrates under vacuum 10-5mbar. The thickness
of the films was 220nm. The as -deposited films were annealed to
different annealing temperatures (373, 423, and 473) K under
vacuum 10-3mbar for 1 h. The structural properties of the films were
examined using X-ray diffraction (XRD). The results show that no
clear diffraction peaks in the range 2θ= (20-50)o for the as deposited
films. On the other hand, by annealing the films to 423K in vacuum
for 1 h, a weak reflection peak attributable to cubic NiO was
detected. On heating the films at 473K for 1 h, this peak was
observed to be stronger. The most intense peak is at 2θ = 37
Gas Chromatography GC, Gas Chromatography–Mass spectrometry GC/MS techniques used for analysis of the crude oils that taken from (10) producing wells in Nasiriyah oil field including (NS-1, NS-3, NS-4, NS-5, NS-6, NS-7, NS-8, NS-9, NS-10, and NS-12) from Mishrif reservoir . This reservoir is one of the important reservoirs in Al-Nasiriyah oil field, and it will be the main subject in the current study in order to provide information of crude oil analysis in this area, also to provide information on its characterizations. Mishrif Formation is one of the principle carbonate reservoir in central and southern Iraq. It is part of the wasia group and widespread throughout the Arabian gulf, It is deposited during Cenomanian-Early Turonian cyc
... Show MoreThis Study aims to engineering geological evaluation of Fatha and Injana Formations in northern Hamrin anticline throughout geological and engineering geological Survey including Preparing engineering geological map (Scale1:90000) and Studying rock Slopes Stability in (6) Stations ,representing all types of failures (taken place and possible).General Survey for rock Slopes included Classification and engineering description according to [1], [2]. The slopes in the area are Classified based on the direction of the Strike Slopes and Strike of beds into Parallel, Oblique Lateral and orthogonal Slopes according to [3].Classification and the Slope Types are Concordant Slope and discordant Slope . The rocks in the area consists of two engineer
... Show MoreAsthma is a disease characterized by hyper reactivity of the trachea and bronchi to reversible either spontaneously or as a result of treatment.
In this study serum magnesium, Zinc, and reduced glutathione levels
were meas ured in order to determine their levels in the asthmatic patients and comparing these levels with healthy controls.
Fifty- four asthmatic patients were enrolled in the study and had their pulmonary function test, and the levels of Mg,Zn
... Show MoreObjective:
To assess the subjective rating of quality of life of college students in University Of Science And Technology in Jordan as a sample of healthy educated
young population through applying the WHOQOL-BREF instrument as a field trial in Jordan and to compare the finding with similar previous study.
Methods
Three hundreds forms of Arabic version of the self-reporting questionnaire WHOQOL-BREF were distributed to students of third class attending the lecture
halls in three colleges (college of Engineering, college of science, college of medicine) in the university campus in AL Ramtha–Jordan from the first of March
to first of may 2007., with respect to university regulations,interested parti