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.
This research aims to know the intellectual picture the displaced people formed about aid organizations and determine whether they were positive or negative, the researchers used survey tool as standard to study the society represented by displaced people living in Baghdad camps from Shiites, Sunnis, Shabak, Turkmen, Christians, and Ezidis.
The researcher reached to important results and the most important thing he found is that displaced people living in camps included in this survey hold a positive opinion about organizations working to meet their demands but they complain about the shortfall in the health care side.
The research also found that displaced people from (Shabak, Turkmen, and Ezidi) minorities see that internati
Recently, complementary perfect corona domination in graphs was introduced. A dominating set S of a graph G is said to be a complementary perfect corona dominating set (CPCD – set) if each vertex in is either a pendent vertex or a support vertex and has a perfect matching. The minimum cardinality of a complementary perfect corona dominating set is called the complementary perfect corona domination number and is denoted by . In this paper, our parameter hasbeen discussed for power graphs of path and cycle.
Many critics suggest that Beckett’s early plays are comic because they focus their analyses on the use comic elements. Waiting for Godot is one of Beckett’s early plays, and it has been heavily analyzed and read as a comic text partly because its subtitle is “a tragicomedy in two acts” and also because of the comic techniques used in the play. The present paper, however, attempts to read the play as a piece in which comedy fails to produce any effects on the characters who remain apparently very desperate and frustrated throughout the play. The characters perform different comic acts, but they do not really feel amused or entertained. The paper suggests that the acts these characters put on stage are only means to pass t
... Show MoreAThe Bridge Maintenance Management System (BMMS) is an application system that uses existing data from a Bridge Management System database for monitoring and analysis of current bridges performance, as well as for estimating the current and future maintenance and rehabilitation needs of the bridges. In a transportation context, the maintenance management is described as a cost-effective process to operate, construct, and maintain physical money. This needs analytical tools to support the allocation of resources, materials, equipment, including personnel, and supplies. Therefore, Geographic Information System (GIS) can be considered as one tool to develop the road and bridge maintenanc
To make iron oxide nanoparticles (IONPs), a simple chemical approach was used to combine iron chloride (FeCl2+FeCl3) salt with onion peel extract. According to the study, iron salts can be converted into IONPs by the biomolecules in onion peel extract. From FeCl2+FeCl3 to γ -Fe2O3, the approach changes iron oxide NPs' size, shape, purity and phases. In water treatment, γ -Fe2O3 NPs are critical for the removal of the color methylene blue (MB). X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet (UV-Vis) and photoluminescence (PL) spectroscopy were used to identify IONPs. Results from the XRD experiment showed crystals having a
... Show MoreThe current research aims to identify measure classroom flexibility for kindergartens children, identify the correlation between the classroom flexibility of kindergartens children and the gender of the child, and identify the correlation between the classroom flexibility of kindergartens children and their classroom. The current research sample consisted of (200) boys and girls selected randomly from the governmental Riyadh affiliated with the six directorates of education of Baghdad on both sides (al-karkh - al-rasafa). in order to achieve the objectives of the current research, this required including two tools, one is the scale of classroom flexibility for the kindergartens' children, which was constructed by the researcher based on
... Show More