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Thermal Efficiency for Passive Solar Chimney with and Without Heat Storage material
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In this study, a different design of passive air Solar Chimney(SC)was tested by installing it in the south wall of insulated test room in Baghdad city. The SC was designed from vertical and inclined parts connected serially together, the vertical SC (first part) has a single pass and Thermal Energy Storage Box Collector (TESB (refined paraffin wax as Phase Change Material(PCM)-Copper Foam Matrix(CFM))), while the inclined SC was designed in single pass, double passes and double pass with TESB (semi refined paraffin wax with copper foam matrix) with selective working angle ((30o, 45o and 60o). A computational model was employed and solved by Finite Volume Method (FVM) to simulate the air induced through the test room by SC effect. The governing equation of Computational Fluid Dynamic (CFD) model was developed by the effective heat capacity method equation to describe the heat storage and release from PCM-CFM. Practical and computational Results referred to increase in thermal conductivity of the paraffin wax that supported by CFM than 10 times, while the ventilation effect is still active for hours after sun set amount. The maximum ventilation mass flow rate with TESB collector was 36.651 kg/hr., when the overall discharge coefficient equals 0.371. Also, the experimental results referred to the best working angle range 45~60o, while the highest approaching temperature (between air and collector) was appeared for the double passes flat plate collector. Results gave higher heat storage efficiency 47% when the maximum solar radiation 780 W/m2 at 12.00 pm, and the energy summation through duration of charging time was 18460 kJ. Double passes SC at 60o angle presented the highest efficiency with value approaching to 73%, while TESB collector efficiency depicted highest efficiency value 70% at 12:00 pm.

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Publication Date
Wed Sep 29 2021
Journal Name
College Of Islamic Sciences
The attitude of Imam Ibn Jarir al-Tabari to the occurrence of unanimous and its convening by statement of the majority in light of his interpretation - Jami` al-Bayan on the interpretation of the verse of the Qur’an -‘‘Applied Models’’
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The research deals with the statement of the importance of unanimous in Islamic Sharia in terms of being the third source of Islamic legislation after the Holy Qur’an and the Sunnah of the Prophet, and the extent of interest of the scholars of interpretation in it, and those who took great interest in mentioning what was agreed upon in every site that necessitated mentioning its issues within, or mentioning an event that has encountered an unanimous, and in various sciences, to extract and extrapolate Sharia rules when these rules are lost in the texts, because it is based on them and derived from them. Among these distinguished scholars is Muhammad bin Jarir al-Tabari. Besides, the research discusses in

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Publication Date
Tue May 01 2018
Journal Name
Journal Of Physics: Conference Series
Partial substitution of Zn Effects on the Structural and Electrical Properties of High Temperature Hg<sub>0.95</sub>Ag<sub>0.05</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>8+δ</sub> Superconductors
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Publication Date
Mon Oct 01 2018
Journal Name
Iraqi Journal Of Physics
A three-stage blumlein-circuit to generate transversely excited atmospheric nitrogen laser by using three spark gaps
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In this research constructed N2 laser system by use developed method of electric discharge. In this method used four step of electric discharge by using four capacitors, three spark gaps, high tension power supply varying in range from 12kV to 24 kV and three resistors, this method called three stage blumlein circuit. The breakdown time delay of these parallel spark gaps cement strong ultraviolet preionization in the laser channel, thus the result of these amendments the laser output is many doubled and is more increasing than that obtained using the one and two stage blumlein circuits. This system has been designed and operated to give pulse laser with wavelength at 337.1 nm. This laser system can operate without mirrors and optical res

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Publication Date
Mon Jul 01 2019
Journal Name
Journal Of Physics: Conference Series
Cu (In, Ga) Se2 an absorber layer of photovoltaic devices
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CIGS nanoink has synthesized from molecular precursors of CuCl, InCl3, GaCl3 and Se metal heat up 240 °C for a half hour in N2-atmosphere to form CIGS nanoink, and then deposited onto substrates of soda-lime glass (SLG). This work focused on CIGS nanocrystals, indicates their synthesis and applications in photovoltaic devices (PVs) as an active light absorber layers. in this work, using spin-coating to deposit CIGS layers (75 mg/ml and 500 nm thickness), without selenization at high temperatures, were obtained up to 1.398 % power conversion efficiency (PCE) at AM 1.5 solar illumination. Structural formations of CIGS chalcopyrite structure were studied by using x ray diffraction XRD. The morphology and composition of CIGS were studied using

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Publication Date
Mon Jun 20 2022
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
BIRDS OF CONSERVATION CONCERN AT AL-NAJAF DESERT, SOUTHERN DESERT OF IRAQ
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One eighth of the bird species in the world is considered globally threatened; the avifauna of Iraq comprises 409 species and is considered as the major indicator of the health of Iraq’s biological resources. The Iraqi geography falls into five main regions among which is the desert and semi-desert areas which cover much of the country area. Al-Najaf desert is still one of the poorly known regions from the biodiversity point of view. Birds of conservation concern are detected in Al-Najaf desert during 31 field trips to 20 sites conducted from August 2018 to April 2020, (citing literature records, and personal interviews with locals).The factors caused the bird numbers to decline in Al-Najaf desert include hunting and trapping, logging,

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Publication Date
Mon Jul 01 2019
Journal Name
Journal Of Physics: Conference Series
Effect of Nickel Substitution On Structural and Electrical Properties of Hg<sub>0.5</sub>Pb<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3-y</sub>Ni<sub>y</sub>O<sub>8+δ</sub> Superconductor Composite
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Abstract<p>six specimens of the Hg<sub>0.5</sub>Pb<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3-y</sub> <italic>Ni<sub>y</sub> </italic>O<sub>8+δ</sub> (y=0.2,0.4,0.6,0.8,1.0) superconducting compound were prepared by solid state reaction method, with sintering temperature equal to 1123K for 24 hours. The electrical resistivity was examined by the four probe technique, It was found that all the specimens have metallic behavior and increasing the critical temperature with increasing nickel concentration. The optimum critical temperature T<sub>c</sub> was found equal </p> ... Show More
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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
The substitutions of Strontium by yttrium and their effects on Bi<sub>2</sub>Sr<sub>2</sub>-<sub>x</sub>Y<sub>x</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10</sub>+<sub>δ</sub> superconducting compound
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Abstract<p>Superconducting compound Bi<sub>2</sub>Sr2-<sub>x</sub>Y<sub>x</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10+δ</sub> were Synthesized by method of solid state reaction, at 1033 K for 160 hours temperature of the sintering at normal atmospheric pressure where substitutions Yttrium oxide with Strontium. When Y2O3 concentration (0.0, 0.1, 0.2, 0.3, 0.4 and 0.5). All specimens of Bi<sub>2</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10+δ</sub> superconducting compounds were examined. The resistivity of electrical was checked by the four point probe technique, It was found th</p> ... Show More
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Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Some electrical properties of PVA:PEG/MnCl2 thin film composites
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PVA:PEG/MnCl2 composites have been prepared by adding (MnCl2) to the mixture of the poly vinyl alcohol (PVA) and poly ethylene glycol (PEG) with different weight percentages (0, 2, 4, 6, 8 and 10) wt.% by using casting method. The type of charge carriers, concentration (nH) and Hall mobility (μH) have been estimated from Hall measurements and show that the films of all concentration have a negative Hall coefficient. In D.C measurement increase temperature leads to decrease the electrical resistance. The D.C conductivity of the composites increases with the increasing of the concentration of additive particles and temperature. The activation energy decreases for all composites with increasing the concentration of the additive particles.

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Publication Date
Fri Oct 01 2021
Journal Name
Journal Of Engineering
Influence of Using Various Percentages of Slag on Mechanical Properties of Fly Ash-based Geopolymer Concrete
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In order to implement the concept of sustainability in the field of construction, it is necessary to find an alternative to the materials that cause pollution by manufacturing, the most important of which is cement. Because factory wastes provide siliceous and aluminous materials and contain calcium such as fly ash and slag that are used in the production of high-strength geopolymer concrete with specifications similar to ordinary concrete, it was necessary for developing this type of concrete that is helping to reduce CO2 (dioxide carbon) in the atmosphere. Therefore, the aim of this study was to study the influence of incorporating various percentages of slag as a replacement for fly ash and the effect of sl

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Publication Date
Mon Aug 01 2022
Journal Name
Baghdad Science Journal
Optimized Artificial Neural network models to time series
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        Artificial Neural networks (ANN) are powerful and effective tools in time-series applications. The first aim of this paper is to diagnose better and more efficient ANN models (Back Propagation, Radial Basis Function Neural networks (RBF), and Recurrent neural networks) in solving the linear and nonlinear time-series behavior. The second aim is dealing with finding accurate estimators as the convergence sometimes is stack in the local minima. It is one of the problems that can bias the test of the robustness of the ANN in time series forecasting. To determine the best or the optimal ANN models, forecast Skill (SS) employed to measure the efficiency of the performance of ANN models. The mean square error and

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