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.
Bacteriophages have the potential to eliminate both antibiotic-resistant and sensitive bacteria; as a result, they have become a major focus of such research. In contrast to antibiotics, which assault the entire bacterial population without discrimination, bacteriophages have a limited set of characteristics that allow them to target infectious microbes while avoiding friendly species (commensal microbiota). Nevertheless, large groups of naturally occurring bacteriophages that are well-differentiated and selective for the most clinically recognized pathogenic bacterial strains are required. Utilizing genetic engineering techniques that modify the target phage genome to synthesize phages with known characteristics in a brief period o
... Show MoreNowadays, information systems constitute a crucial part of organizations; by losing security, these organizations will lose plenty of competitive advantages as well. The core point of information security (InfoSecu) is risk management. There are a great deal of research works and standards in security risk management (ISRM) including NIST 800-30 and ISO/IEC 27005. However, only few works of research focus on InfoSecu risk reduction, while the standards explain general principles and guidelines. They do not provide any implementation details regarding ISRM; as such reducing the InfoSecu risks in uncertain environments is painstaking. Thus, this paper applied a genetic algorithm (GA) for InfoSecu risk reduction in uncertainty. Finally, the ef
... Show MoreImproving the ability of asphalt pavement to survive the heavily repeated axle loads and weathering challenges in Iraq has been the subject of research for many years. The critical need for such data in the design and construction of more durable flexible pavement in bridge deck material is paramount. One of new possible steps is the epoxy asphalt concrete, which is classified as a superior asphalt concrete in roads and greatly imparts the level of design and construction. This paper describes a study on 40-50 penetration graded asphalt cement mixed with epoxy to produce asphalt concrete mixtures. The tests carried out are the Marshall properties, permanent deformation, flexural fatigue cracking and moisture damage. Epoxy asphalt mixes perf
... Show MoreThe current research included palynological study for nine ornamental cultivated species of Asteraceae family. The study included measurement the dimensions of pollen grains and there shape in polar view and equatorial view, sculpturing,colpi length and width, spines length and number of spines rows between colpiand exine thickness, the study showed variations in pollen grains characters forthe studied taxa
Solid waste is considered to be one of the rescuers of pollution in case of neglecting conditions and procedures relating to specific processes of laws, systems, and contracts requirements in addition to recommendations of organizations concerned with environment issue. The environments auditing groups of intosai have taking into account the environments control by various conference and recommended that the Board of supreme audit have and environments controlling taking into consideration auditing procedures on waste management ,and also offered on evidences for experiences of members of countries in order to exchange their knowledge's and experiments .the definition of solid waste and their resources ,risks ,man
... Show MoreA- The research problem: the research problem which is the garments industry, as a
whole it does not rely on a single system in the sizes of the clothing and the working
companies, see that it is not plausible that the sizes be unificd and consistent in all companies.
The current sizes in the domestic Iraqi markets are not suitable for some females ,on the other
hand the Iraqi industry suffers the lack of a modern standard for some Iraqis female bodies.
B- The Signifiance of the research: lies in the study of the diversity of the human body
sizes and naming them to reflect the desires and requirements of the consumer and try to find
a method to meet their expectations as well as to raise the level of garments industr
In the present study, advanced oxidation process / heterogeneous photocatalytic process (UV/TiO2/Fenton) system was investigated to the treatment of oily wastewater. The present study was conducted to evaluate the effect of hydrogen peroxide concentration H2O2, initial amount of the iron catalyst Fe+2, pH, temperature, amount of TiO2 and the concentration of oil in the wastewater. The removal efficiency for the system UV/TiO2/Fenton at optimal conditions and dosage (H2O2 = 400mg/L, Fe+2 = 40mg/L, pH=5, temperature =30oC, TiO2=75mg/L) for 1000mg/L load was found to be 77%.
Aluminum foil cover around the re
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