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 this research was the study of the educational values when Shafei, contained in hair Shafi'i, and that what the role of these values in the education of generations, and the possibility of their application in the educational curriculum. Find addressed Shafei life and his time. The values derived from his hair, as well as quoting from the Koran and influenced by it, which is evident in the hair, governance and eating Alomthal.okzlk Find the importance of this thought in modern education, so as to realism and ease of application. It is the search results, the Shafi'i put thought educationally integral based on the Koran rise to the level of theory. Find and conclusions: that education in its present situation
... Show MoreMass transfer has been studied at rotating cylinder electrodes fabricated with spiral-wound woven-wire meshes using reduction of copper as a test reaction. The experimental data were correlated by an empirical expression between the Sherwood number and the Reynolds number, both regarding the hydraulic diameter as a characteristic length. It was found that the Sherwood number was dependent upon the Reynolds number to the power of 0.521. An enhancement factor was adopted to compare the efficiency of the new rotating cylinder electrode with previous three-dimensional rotating cylinder electrodes. The results showed that the new type has a mass-transfer enhancement factor 2.3 times higher than those obtained with smooth rotating cylinder electr
... Show MoreThe experiment was conducted to study the effect of sodium chloride (NaCl) at the concentrations of 0.0, 0.5, 1.0 and 1.5% on the callus cells. The Iraq wheat variety was grown in vitro for the purpose of knowing the effect of salt stress on some indicators and cellular components of callus by using a randomized complete design, at the laboratories of tissue culture propagation date palm unit in the College of Agriculture / University of Kufa during the period 2014-2015. Fresh and dry weight, the rate of absolute growth, percentage of dry matter of callus, content of the callus cells of proline, total soluble carbohydrates, sodium and potassium ions, effectiveness of the enzymes catalase and peroxidase study shock salt proteins in callus we
... Show MoreToxoplasma gondiiis an obligate intracellular protozoan parasite of the phylum Apicomplexa, and toxoplasmosis is an important disease of both humans and economically important animals. With a limited array of drugs available there is a need to identify new therapeutic compounds. Aureobasidin A (AbA) is an antifungal that targets the essential inositol phosphorylceramide (IPC, sphingolipid) synthase in pathogenic fungi. This natural cyclic depsipeptide also inhibits
Background: Platelet-rich fibrin (PRF) is a simple, low cost and minimally invasive way to obtain a natural concentration of autologous growth factors and is currently being widely experimented in different fields of medicine for its ability to aid the regeneration of tissue with a low healing potential. Fields of application are sports medicine, orthopedics, dentistry, dermatology, ophthalmology, plastic and maxillofacial surgery, etc. The rationale for using platelets in so many fields for the treatment of different tissues is because PLTs constitute a reservoir of critical GFs and cytokines, which may govern and regulate the tissue healing process that is quite similar in all kinds of tissues. Materials and Methods: Screw titanium implan
... Show MoreIn this paper, a theoretical investigation was suggested to study underwater wireless optical communication (UWOC) system based on multiple input–multiple output (MIMO) technique. The modulation schemes such as RZ-OOK, NRZ-OOK, 32-PPM and 4-QAM applied under different coastal water types. MIMO technique enabled the system to transmit data rate with longer distance link. The performance of the proposed system examined by BER and data rate as a metrics. Several impairments such as the types of water by the attenuation of coastal water and the distance link were taken into account for the transmission of the optical signal to appreciate the reliability of the MIMO technique. The theore
This research addresses: Sharh Usul Al-Bazdawi "Explanation of the Fundamentals for Al-Bazdawi", by studying and investigating, from the beginning of prohibition chapter to its end. The researcher conducted a study about this book stating its significance and introducing the compiler and the commentator. The researcher as well mentioned that the prohibition has a special formula and requires repetition, and he went on explaining that prohibition according to Hanafis does not require absolute corruption of the prohibited matter unless based on an evidence, and that what is condemned as wrong act for itself is considered void and what is condemned as wrong act for external reasons is considered corrupt accor
... Show MoreWater is the basis of the existence of all kinds of life, so obtaining it with good quality represents a challenge to human existence and development especially in the desert and remote cities because these areas contain small populations and water purification requires great materials and huge amounts of fossil fuels resulting pollution of the environment. Cheap and environmentally friendly desalination methods have been done by using solar distillations. Passive solar stills have low yields, so in this research, the problem is overcome by connecting four heat pipes which are installed on the parabolic concentrator reflector with passive solar still to increase the temperature of hot water to more than 90°C, as a resul
... Show MoreA mathematical model was proposed to study the microkinetics of esterification reaction of oleic acid with ethanol over prepared HY zeolite catalyst. The catalyst was prepared from Iraqi kaolin source and its properties were characterized by different techniques. The esterification was done under different temperature (40 to 70˚C) with 6:1 for molar ratio of ethanol to oleic acid and 5 % catalyst loading.
The microkinetics study was done over two period of time each period was examined individually to calculate the reaction rate constant and activation energy. The impact of the mass transfer resistance to the reactant was also investigated; two different studies have been accomplished to do this purpose.
&nb
... Show More