Phase change material (PCM) is considered as one of the most effective thermal energy storage (TES) systems to balance energy supply and demand. A key challenge in designing efficient PCM-based TES systems lies in the enhancement of heat transmission during phase transition. This study numerically examines the privilege of employing twisted-fin arrays inside a shell-and-tube latent heat storage unit to improve the solidification performance. The presence of twisted fins contributes to the dominating role of heat conduction by their curved shapes, which restricts the role of natural convection but largely aids the overall heat-transfer process during solidification. The heat-discharge rate of twisted-fin configuration is increased by ∼14 and ∼55% compared to straight fin and no fin configurations—leading to a reduction in the solidification duration by ∼13 and ∼35%, respectively. The solidification front at various times has also been assessed through a detailed parametric study over the fin height, fin pitch number, and fin thickness. Over the range of values assumed, the fin height is the most dominant parameter – increasing the heat-retrieval rate from 10.0 to 11.4 W and decreasing the discharge time from above 3600 to 2880 s by varying the fin height from 2.5 to 7.5 mm.
The research aims to identify the effect of teaching according to the augmented reality on the technique of the visual thinking skills among scientific fifth-grade students in a biology course. In order to achieve the goal of the research, the researcher adopted the experimental approach with the partial set of the two equal groups with the dimensional test of visual thinking skills, The research population represented all the scientific students of the fifth grade for morning government schools affiliated to the General Directorate of Education of Baghdad / Karkh II, alshakerin preparatory for boys was chosen intentionally, in which two groups were chosen for this study, one group is chosen randomly as the control group via lottery, whe
... Show MoreAbstract:
The objective of this study, is to attempt to explain the reality of the Structural Imbalances in the Iraqi Economy during the period of research, by providing a quantitative analysis of the most important types of Imbalances, Which are represented by the disruption in the Productive Structure, the imbalance of the structure of Public Budget, and the imbalance of the Structure of Trade. The problem of the research, is the fact that the economy structure in Iraq has long suffered from an Imbalances in its economic structure, which are represented in the unequal relations between its constituent elements, according to the proportions levels defined by the economic theory.
... Show MoreThe Purpose of this research is analysis and discussion " The Effect of Insurace Company Capital Adequacy in it’s Profitafility: An Empirical Study compared the two insurance (national, Iraqi), for a period of one year (2005) and the year (2014), as it is framed theoretical side for two topics head adequacy money the insurance company, and the profitability of the insurance company, and I've been using the research methodology and analytical, in the analysis and measurement of the capital of the insurance company adequacy, and profitability of the company, as the capital adequacy ratio was measured by dividing the total capital available on the total capital rate risk, after measured and appreciated in two insurance research, while I u
... Show MoreBackground: The Initial (primary) stability is one of the factors that play an important role in the success of the dental implants. The purpose of this study was to evaluate the initial stability of dental implant with horizontal plate by using five analytical tests: insertion torque, removal torque, resonance frequency analysis, push-in test and pull-out test. Materials and methods: Two different lengths of dental implants (5mm and 10mm) were tested in this study; each dental implant was 4mm in diameter with a square threads shape of 1mm pitch and 0.5mm depth. The crestal area was 4.2mm diameter contained a right angle margin circumferential ring while the apical area was tapered with two self-tapping grooves. In this study, the initial s
... Show MoreDrilling with casing (DWC) can be considered as a modern drilling technique in which both of drilling and casing operations done in the same time by using the casing to transfer the hydraulic and mechanical power to the bit instead of traditional drilling string. To overcome oil well control, minimizing the total cost through enhancing drilling efficiency, drilling with casing was proposed as an enabling technology.
Two surface sections (17 1/2 - and 12 1/4- inch) were drilled successfully in Rumaila oil field with casing strings which reached 655m and 1524m measured depths respectively.
By using DWC technique, the total drill/case phase time was reduced up to 20% comparing to conventional
... Show MoreObjective: Dental caries is a chronic infectious disease that is prevalent worldwide in all age groups. Numerous attempts have been made to develop conservative approaches to halt caries progression and restore enamel defects. This study aimed to investigate the effect of applying grape seed extract and chicken eggshell extract on the microhardness of demineralized enamel in permanent teeth. Methods: Forty-eight sound upper first premolars were used. Following demineralization with the demineralizing solution for 96 hours, they were distributed into four groups consistent with the treatment agent used: group A was treated with casein phosphopeptide amorphous calcium phosphate (as a control group), group B was treated with grape se
... Show MoreKeloids are prevalent fibro-proliferative tumors, and treating them is still a challenge although intralesional injections of triamcinolone acetonide (TAC) are effective, they have frequently linked adverse effects. Pentoxifylline (PTX) is an anti-fibrotic and anti-inflammatory, and vasodilator. It has not yet been tested for intralesional injection in keloids. The aim of the study is to study the efficacy of intralesional pentoxifylline versus triamcinolone acetonide in keloid scars of 40 patients. In this study, 40 patients with keloid scars regardless of the cause of keloid born, 20 patients have injected with intralesional triamcinolone acetonide, and 20 patients with intralesional pentoxifylline every two weeks until the lesi
... Show More