This research aims to investigate the thermal performance of different thermal composite insulators, wrapped around a closed-loop copper pipe (CLP). To achieve this aim a system was designed and manufactured. It is consisted of closed water tank insulated by Rock Wool, and supplied with two electric heaters, two thermostat, a flow meter, a water pump, digital temperature scales, and four series of (CLP).
Six insulators were prepared namely; composites of Impregnated Fiberglass with Elastoclad and foaming Rubber (FER), Impregnated Fiberglass with Elastoclad resin and Polymeric Membrane (FEM), Impregnated Fiberglass with Polyurethane thermoset resin and Foaming Rubber (FUR), Impregnated Fiberglass with Polyurethane thermoset resin and Polymeric Membrane (FUM), Fiberglass woven tape (F) , and foaming rubber tape (R). Thermal conductivities of all composite specimens were measured by Lee's Disc device and their thermal performances were evaluated by measuring inlet and outlet temperature ΔTw at different flow rates. It was found from all test results that ΔTw decreased as flow rate increased.
The optimum result was obtained for the (FER) insulator at flow rate 8 L/min where ΔTw = 0.8 oC (efficiency η = 99 %).
Thermal efficiency of the prepared insulators was according to the following sequence:
FER > FEM > FUR > FUM >R > F
In this work, a series of new maleimides linked to substituted benzothiazole moiety were synthesized. Synthesis of these new cyclic imides were performed via three steps, the first one involved preparation of a series of 2-aminobenzothiazole substituted with different substituents via reaction of different primary aromatic amines with ammonium thiocyanate and bromine in glacial acetic acid. The prepared 2- amino benzothiozoles were introduced in the second step in reaction with maleic anhydride producing a series of N-(substituted benzothiazole-2-yl) maleamic acids.The resulted maleamic acids were dehydrated in the third step via treatment with acetic anhydride and anhydrous sodium acetate to afford a series of the desirable N-(substitu
... Show MoreGalway Kinnell (1927-) is considered as one of the most important contemporary American poets who brought about a drastic change in the American poetry of the nineteen sixties. Kinnell's poetry is characterized by being simple in style and deep in content. Poetry for him is a means through which he perceives the inner levels of consciousness in an attempt to comprehend the depths of the American self. Therefore, he writes narrative poems in which the emphasis is not on the rhetorical effects, but on the inner transformations through which the poet goes.
"The Bear" (1968) is typical of Kinnell's introspective poetry. It takes the form of a journey in which the rituals of hunting are used allegorically to embody the state of the sp
... Show MoreSpatial data observed on a group of areal units is common in scientific applications. The usual hierarchical approach for modeling this kind of dataset is to introduce a spatial random effect with an autoregressive prior. However, the usual Markov chain Monte Carlo scheme for this hierarchical framework requires the spatial effects to be sampled from their full conditional posteriors one-by-one resulting in poor mixing. More importantly, it makes the model computationally inefficient for datasets with large number of units. In this article, we propose a Bayesian approach that uses the spectral structure of the adjacency to construct a low-rank expansion for modeling spatial dependence. We propose a pair of computationally efficient estimati
... Show MoreSuccessfully, theoretical equations were established to study the effect of solvent polarities on the electron current density, fill factor and efficiencies of Tris (8-hydroxy) quinoline aluminum (Alq3)/ ZnO solar cells. Three different solvents studied in this theoretical works, namely 1-propanol, ethanol and acetonitrile. The quantum model of transition energy in donor–acceptor system was used to derive a current formula. After that, it has been used to calculate the fill factor and the efficiency of the solar cell. The calculations indicated that the efficiency of the solar cell is influenced by the polarity of solvents. The best performance was for the solar cell based on acetonitrile as a solvent with electron current density of (5.0
... Show MoreEndometriosis is an estrogen dependent inflammatory disorder plays a pivotal role in the reproductive system of the females which regarded as one of the most important gynecological disorders due to it is a key cause of infertility for women and also it has a remarkable impact on the women's life quality. Indeed, environmental pollution have an extremely importance in the etiology of endometriosis. Hence, the present article submits an abbreviated literature review to the biochemical role of environmental pollutants in the etiology and development of endometriosis. Anyway, this review article represented the major environmental pollutants: the organic pollutants of air, heavy metals, gaseous pollutants and the particulate matter. Th
... Show MoreAn innovative two-step noncatalytic esterifcation technique was proposed to synthesize alkyl esters from free fatty acids simulated in waste cooking oil, as a pretreatment process for biodiesel production, without adding any catalyst under normal conditions of pressure and temperature. The efect of methanol:oil molar ratio, reaction time, mixing rate, and reaction temperature were investigated. The results confrmed that the conversion of the reaction was increased when increasing the methanol molar ratio and decreased in prolonged reaction temperature. High conversion (94.545%) was successfully achieved at optimized conditions of 115:1, 65:1 methanol:oil molar ratio in the frst step and second step, respectively, other conditions i
... Show MoreThe aim of this study is to evaluating the antibacterial activity of Laurus nobilis leaves extract on E. coli isolates. Maceration and Soxhlet apparatus were used to prepare aqueous and methanolic extracts; total phenolic content and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were conducted to determine the active compounds in the extracts. The results showed that both Laurus nobilis methanolic and aqueous extracts have a noticeable effect on scavenging free radicals. Free radical scavenging activity. The total phenolic contents were 28.60 ±0.12 and 16.58 ±0.11mg/g in 50 mg/ml, in methanolic and aqueous extracts respectively. The antibacterial activity of Laurus nobilis leaves extracts showed that the methanolic extract was more effective than
... Show More