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alkej-148
Experimental Investigation of Using Evaporative Air Cooler for Winter Air-Conditioning in Baghdad
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This paper presents an efficient methodology to design modified evaporative air-cooler for winter air-conditioning in Baghdad city as well as using it for summer air-conditioning by adding a heating process after the humidification process. laboratory tests were performed on a direct evaporative cooler (DEC) followed by passing the air on hot water through heat exchanger placed in the coolers air duct exit. The tests were conducted on the 2nd of December /2011 when the ambient temperature was 8.1°C and the relative humidity was  (68%). The air flow rate is assumed to vary between 0.069 to 0.209 kg/s with constant water flow rate of 0.03 kg/s in the heat exchanger. The performance is reported in terms of effectiveness of DEC, saturation efficiency of DEC, outlet temperature of air and cooling capacity. Heat transfer rate in heat exchanger mode is also estimated. The paper presents the mathematical development of the equations of thermal exchanges through DEC and HE. prediction of air condition that exits o this system show that the present system could bring the air stream to a comfortable winter zone .

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Preparation and Characterization of Bimetallic Catalyst (NiO – CoO) for Desulfurization of Gas Oil
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In this study NiO - CoO bimetallic catalysts are prepared with two Ni/Co ratios (70:30 and 80: 20) using the precipitation method of nitrate salts. The effects of Ni /Co ratio and preparation methods on the catalyst are analyzed by using different characterization techniques, i.e. atomic absorption (AA) , XRD, surface area and pore volume measurements according to the BET method . The results indicate that the best catalyst is the one containing the percentage of Ni :Co ( 70 : 30 ). Experiments indicate that the optimal conditions to prepare catalyst are stirring for three hours at a temperature of 60oC of the preparation , pH= (8-9) , calcination temperature at 400oC for two hours

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Publication Date
Fri Jun 24 2022
Journal Name
Iraqi Journal Of Science
Water Balance for Ali AL-Gharbi-Northeast of Missan Governorate- Southeast of Iraq
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Ali AL-Gharbi area lies to the northeast of Missan Governorate, southeast of Iraq. The meteorological data recorded in Ali AL-Gharbi station for the period (1994-2014) were used to assess the climatic condition of the study area, it was found that the monthly mean of rainfall is (15.35 mm), relative humidity (43.95 %), the temperature (24.50 C◦), wind speed (4.35 m/sec) and the strongest and most frequent winds are the northwest, sunshine (8.54 h/day) and evaporation (305.73 mm).The results of the data analysis show that, the climate of study area is characterized by dry and relatively hot in summer, and cold with low rain in winter. This study shows that, there is water surplus of (35.69 %) of the total rainfall amount which is equivalen

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Publication Date
Thu Mar 30 2023
Journal Name
Iraqi Journal Of Science
Determination of the Mathematical Model for Plasma Electronic Coefficients of the Earth's Ionosphere
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In this research, electron coefficients such as total collision frequency (colt/N), total ionization frequency (viz/N), and Power (P/N) for different gases such as (Ar, He, N2 and O2 (in Earth’s ionosphere have been calculated by applying the Boltzmann equation utilizing BOLSIG +, and it has been discovered that there is a significant impact of reducing the electric field (E/N) on electronic coefficients under which (E/N) increases. In addition, influence of (E/N) on electronic coefficients was studied. Reducing the electric field was chosen in the restricted range (1-100) Td, and the electronic coefficients for gases in the limited range (50-2000) km of the Earth's ionosphere. A positive correlation has been explained between all the

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Publication Date
Wed Apr 01 2020
Journal Name
Civil Engineering Journal
Model Development for the Prediction of the Resilient Modulus of Warm Mix Asphalt
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Increasing material prices coupled with the emission of hazardous gases through the production and construction of Hot Mix Asphalt (HMA) has driven a strong movement toward the adoption of sustainable construction technology. Warm Mix Asphalt (WMA) is considered relatively a new technology, which enables the production and compaction of asphalt concrete mixtures at temperatures 15-40 °C lower than that of traditional hot mix asphalt. The Resilient modulus (Mr) which can be defined as the ratio of axial pulsating stress to the corresponding recoverable strain, is used to evaluate the relative quality of materials as well as to generate input for pavement design or pavement evaluation and analysis. Based on the aforementioned preface, it is

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Publication Date
Tue Sep 29 2020
Journal Name
Reaction Kinetics, Mechanisms And Catalysis
Development of two-step noncatalytic esterification of waste cooking oil for biodiesel preparation
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An 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

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Publication Date
Tue May 16 2023
Journal Name
Journal Of Engineering
Application of Wavelet Packet and S Transforms for Differential Protection of Power Transformer
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The differential protection of power transformers appears to be more difficult than any type of protection for any other part or element in a power system. Such difficulties arise from the existence of the magnetizing inrush phenomenon. Therefore, it is necessary to recognize between inrush current and the current arise from internal faults. In this paper, two approaches based on wavelet packet transform (WPT) and S-transform (ST) are applied to recognize different types of currents following in the transformer. In WPT approach, the selection of optimal mother wavelet and the optimal number of resolution is carried out using minimum description length (MDL) criteria before taking the decision for the extraction features from the WPT tree

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
A Comparison of Bayes Estimators for the parameter of Rayleigh Distribution with Simulation
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   A comparison of double informative and non- informative priors assumed for the parameter of Rayleigh distribution is considered. Three different sets of double priors are included, for a single unknown parameter of Rayleigh distribution. We have assumed three double priors: the square root inverted gamma (SRIG) - the natural conjugate family of priors distribution, the square root inverted gamma – the non-informative distribution, and the natural conjugate family of priors - the non-informative distribution as double priors .The data is generating form three cases from Rayleigh distribution for different samples sizes (small, medium, and large). And Bayes estimators for the parameter is derived under a squared erro

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Crossref
Publication Date
Thu Sep 30 2021
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of Some Methods for Estimating Mixture of Linear Regression Models with Application
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 A mixture model is used to model data that come from more than one component. In recent years, it became an effective tool in drawing inferences about the complex data that we might come across in real life. Moreover, it can represent a tremendous confirmatory tool in classification observations based on similarities amongst them. In this paper, several mixture regression-based methods were conducted under the assumption that the data come from a finite number of components. A comparison of these methods has been made according to their results in estimating component parameters. Also, observation membership has been inferred and assessed for these methods. The results showed that the flexible mixture model outperformed the

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Publication Date
Wed Dec 13 2017
Journal Name
Al-khwarizmi Engineering Journal
Design and Simulation of L1-Adaptive Controller for Position Control of DC Servomotor
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This paper presents L1-adaptive controller for controlling uncertain parameters and time-varying unknown parameters to control the position of a DC servomotor. For the purpose of comparison, the effectiveness of L1-adaptive controller for position control of studied servomotor has been examined and compared with another adaptive controller; Model Reference Adaptive Controller (MRAC). Robustness of both L1-adaptive controller and model reference adaptive controller to different input reference signals and different structures of uncertainty were studied. Three different types of input signals are taken into account; ramp, step and sinusoidal. The L1-adaptive controller ensured uniformly bounded

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Publication Date
Sun Mar 30 2008
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Pyrolysis of High-density Polyethylene for the Production of Fuel-like Liquid Hydrocarbon
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Pyrolysis of high density polyethylene (HDPE) was carried out in a 750 cm3 stainless steel autoclave reactor, with temperature ranging from 470 to 495° C and reaction times up to 90 minute. The influence of the operating conditions on the component yields was studied. It was found that the optimum cracking condition for HDPE that maximized the oil yield to 70 wt. % was 480°C and 20 minutes. The results show that for higher cracking temperature, and longer reaction times there was higher production of gas and coke. Furthermore, higher temperature increases the aromatics and produce lighter oil with lower viscosity.

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