This study reports on natural convection heat transfer in a square enclosure of length (L=20 cm) with a saturated porous medium (solid glass beads) having same fluid (air) at lower horizontal layer and free air fill in the rest of the cavity's space. The experimental work has been performed under the effects of heating from bottom by constant heat flux q=150,300,450,600 W/m2 for four porous layers thickness Hp (2.5,5,7.5,1) cm and three heaters length δ(20,14,7) cm. The top enclosure wall was good insulated and the two side walls were symmetrically cooled at constant temperature. Four layers of porous media with small porosity, Rayleigh number range (60.354 - 241.41) and (Da) 3.025x10-8 has been investigated. The obtained data of temperature from testing rig are used to extract the temperature distribution, local Nusselt number and average Nusselt number. Moreover, a comparison between the numerical result of the same problem published recently and present experimental results has been executed and discussed. It is evinced that; the heat transfer and fluid flow are affected by thickness of porous layer and be maximum at porous layer thickness (0.25L) with larger heater length(20cm) and heat flux (q= 600 Watt/m2) which is approximately (180%) for the average Nu when compared with (Hp=0.75L). Also, the effect of the increasing in heater length (δ) on the averaged heat transfer enhancement is more pronounced for large heater size and 25% of average enhancement is achieved for (δ=20cm) compared to (δ=7cm). However, the greater temperature distribution is found at Hp=2.5cm and 5cm at bottom and first quarter of the cavity (heater surface height Y=0 cm and Y=5 cm) respectively and minimum temperature at top (insulation wall Y=20 cm). Nearly, same shape for heat transfer for different case with clearly difference at small heater (δ=7cm).
Abstract:
The models of time series often suffer from the problem of the existence of outliers that accompany the data collection process for many reasons, their existence may have a significant impact on the estimation of the parameters of the studied model. Access to highly efficient estimators is one of the most important stages of statistical analysis, And it is therefore important to choose the appropriate methods to obtain good estimators. The aim of this research is to compare the ordinary estimators and the robust estimators of the estimation of the parameters of
... Show MoreA new Schiff base [1-((2-(1H-indol-3-yl)ethylimino)methyl)naphthalene-2-ol] (HL) has been synthesized by condensing (2-hydroxy-1-naphthaldehyde) with (2-(1H-indol-3-yl)ethylamine). In turn, its transition metal complexes were prepared having the general formula; [Pt(IV)Cl2(L)2], [Re(V)Cl2(L)2]Cl and [Pd(L)2], 2K[M(II)Cl2(L)2] where M(II) = Co, Ni, Cu] are reported. Ligand as well as metal complexes are characterized by spectroscopic techniques such as FT-IR, UV-visible, 13C & 1H NMR, mass, elemental analysis. The results suggested that the ligand behaves like a bidentate ligand for all the synthesized complexes. On the other hand, theoretical studies of the ligand as well its metal complexes were conducted at gas phase using Hyp
... Show Moreفي هذا البحث تم تحضير المركبات المعدنية النانوية الجديدة لأيونات البلاتين 4+و الذهب 3+ مع ليكاند قاعدة مانخ جديد مشتق من السيبروفلوكساسين بطريقة الموجات فوق الصوتية. تم تشخيص المعقدات النانوية والليكاند الجديد بأستخدام تقنيات فيزيائية و كيميائية مختلفة مثل أطياف الاشعة تحت الحمراء، حيود الاشعة السينية ، المجهر الالكتروني الماسح ، المجهر الالكتروني النافذ و مجهر القوة الذرية. تم تحديد نشاط مضادات الأك
... Show MoreRespiratory tract infections in sheep are among the important health problems that affect all sheep ages around the world. Nine bacterial isolates obtained from sheep with respiratory tract infections were selected to be used in the current study. The isolates included 3 Staphylococcus aureus, 4 Klebsiella pneumoniae, and 2 Pseudomonas aeruginosa. Following the primers design by the Primer3Plus software tool and optimization of the conventional polymerase chain reaction (PCR), the primers were validated for their use in the multiplex PCR experiments. The MFEprimer program was used to check the suitability of the primer set combinations for multiplex PCR. The MFEprimer software was successful in designing the multiplex-PCR experiments and de
... Show MoreThis research deals with one scene from the movie Romeo and Juliet, which is the balcony scene, due to the importance of this scene in the formation of the construction of the subsequent events of the movie.
The first chapter contained the methodological framework of the research, where the research problem was identified in how Zeffirelli dealt with the balcony scene in the play Romeo and Juliet and enriched it in the cinematic language with a comparison with the original text of the scene. In the balcony scene with comparative parts between the film and the text and the limits of the research that was limited to the film Zeffirelli and the translated text by Munis Taha Hussein.
The second chapter contained the theoretic
... Show MoreThe nucleon momentum distributions (NMD) and elastic electron scattering form factors of the ground state for some 1f-2p-shell nuclei, such as 58Ni, 60Ni, 62Ni, and 64Ni
isotopes have been calculated in the framework of the coherent fluctuation model (CFM) and expressed in terms of the weight function lf(x)l2 . The weight function (fluctuation function) has been related to the nucleon density distribution (NDD) of the nuclei and determined from the theory and experiment. The NDD is derived from a simple method based on the use of the single particle wave functions of the harmonic oscillator potential and the occupation numbers of the states. The feature of the l
Objective(s): To assess the level of depression and anxiety among school age children with acute lymphoblastic leukemia under chemotherapy treatment and to find out the relationship between the level of depression and anxiety among the affected children and their demographic characteristics.
Methodology: A cross-sectional study was conducted on school age children both gender having acute lymphoblastic leukemia under chemotherapy treated and their age between 6 years to 12 years. The study started from the period of September, 19th 2020 to March,1st 2021. Non-probability (Purposive) sample of (114) children with acute lymphoblastic leukemia under chemotherapy was selected in attending hospital wards, outpatient and counseling clinics
This paper presents a computer simulation model of a thermally activated roof (TAR) to cool a room using cool water from a wet cooling tower. Modeling was achieved using a simplified 1-D resistance-capacitance thermal network (RC model) for an infinite slab. Heat transfer from the cooling pipe network was treated as 2-D heat flow. Only a limited number of nodes were required to obtain reliable results. The use of 6th order RC-thermal model produced a set of ordinary differential equations that were solved using MATLAB - R2012a. The computer program was written to cover all possible initial conditions, material properties, TAR system geometry and hourly solar radiation. The cool water supply was considered time
... Show MorePlantation of humic acid nanoparticles on the inert sand through simple impregnation to obtain the permeable reactive barrier (PRB) for treating of groundwater contaminated with copper and cadmium ions. The humic acid was extracted from sewage sludge which is byproduct of the wastewater treatment plant; so, this considers an application of sustainable development. Batch tests signified that the coated sand by humic acid (CSHA) had removal efficiencies exceeded 98 % at contact time, sorbent dosage, and initial pH of 1 h, 0.25 g/50 mL and 7, respectively for 10 mg/L initial concentration and 200 rpm agitation speed. Results proved that physicosorption was the predominant mechanism for metals-CSHA interaction because the sorption data followed
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