Preferred Language
Articles
/
alkej-463
Numerical Investigation of Transient Heat Conduction through a Thermal Insulation of Temperature Dependant Thermal Properties
...Show More Authors

The two-dimensional transient heat conduction through a thermal insulation of temperature dependent thermal properties is investigated numerically using the FVM. It is assumed that this insulating material is initially at a uniform temperature. Then, it is suddenly subjected at its inner surface with a step change in temperature and subjected at its outer surface with a natural convection boundary condition associated with a periodic change in ambient temperature and heat flux of solar radiation. Two thermal insulation materials were selected. The fully implicit time scheme is selected to represent the time discretization. The arithmetic mean thermal conductivity is chosen to be the value of the approximated thermal conductivity at the interface between adjacent control volumes. A temperature dependent specific heat capacity proposed by a 4th Degree polynomial is fitted. A good agreement is obtained when the predicted results are compared with those obtained from the analytical solution.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Dec 18 2019
Journal Name
Baghdad Science Journal
Spectrophotometric Determination of Mesalazine in Pharmaceutical Preparations by Oxidative Coupling Reactions with m-Aminophenol and 2,6- Dihydroxybenzoic Acid
...Show More Authors

     Tow simple, rapid and sensitive spectrophotometric methods for the determination of mesalazine in pharmaceutical preparations have been carried out. The proposed methods depend on oxidative coupling reaction of mesalazine with m-aminophenol in the existence of N-bromosuccinamide in alkaline medium (method A) and 2,6-dihydroxybenzoic acid in the existence of sodium metaperiodate in basic medium (method B) to produce colored products , show highest absorptions at 640 (nm) and 515 (nm), alternately. Beer’s law was consistent in concentrations extent of 1.25-30 and 0.5-12.5 (µg.mL-1) with molar absorptivity of 0.36×104 and 0.77×104 L.mol-1.cm<

... Show More
View Publication Preview PDF
Scopus (5)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Fri Nov 01 2019
Journal Name
Journal Of Engineering
Prediction of Heat Transfer Coefficient and Pressure Drop in Wire Heat Exchanger Working with R-134a and R-600a
...Show More Authors

An experimental and theoretical works were carried out to model the wire condenser in the domestic refrigerator by calculating the heat transfer coefficient and pressure drop and finding the optimum performance. The two methods were used for calculation, zone method, and an integral method. The work was conducted by using two wire condensers with equal length but different in tube diameters, two refrigerants, R-134a and R-600a, and two different compressors matching the refrigerant type. In the experimental work, the optimum charge was found for the refrigerator according to ASHRAE recommendation. Then, the tests were done at 32˚C ambient temperature in a closed room with dimension (2m*2m*3m). The results showed that th

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Aug 13 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Temperature and Doping Dependencies Junction Of Polythiophene Schottky Barrier
...Show More Authors

 The junction between  polythiophene,  a conducting  polymer formed by  electrochemical polymerization,  and n-type silicon was  studied the temperature and doping dependencies were observed in the junction characteristics. The increase of junction  temperature leads to increase the saturation current, the barrier height, and decrease of the ideality factor for  junction. While the reduction in doping concentration causes a decrease  in the forward current. The results were  explained  according to the conventional  Schottky diode theories. 

View Publication Preview PDF
Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Temperature Effect on Power Drop of Different Photovoltaic Modules
...Show More Authors

Solar module operating temperature is the second major factor affects the performance of solar photovoltaic panels after the amount of solar radiation. This paper presents a performance comparison of mono-crystalline Silicon (mc-Si), poly-crystalline Silicon (pc-Si), amorphous Silicon (a-Si) and Cupper Indium Gallium di-selenide (CIGS) photovoltaic technologies under Climate Conditions of Baghdad city. Temperature influence on the solar modules electric output parameters was investigated experimentally and their temperature coefficients was calculated. These temperature coefficients are important for all systems design and sizing. The experimental results revealed that the pc-Si module showed a decrease in open circuit v

... Show More
View Publication Preview PDF
Publication Date
Mon Jun 30 2003
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Two-Phase Pressure Drop Through Obstructions
...Show More Authors

View Publication Preview PDF
Publication Date
Wed Feb 19 2020
Journal Name
International Journal Of Innovation, Creativity And Change
Secure Image Steganography Through Multilevel Security
...Show More Authors

The concealment of data has emerged as an area of deep and wide interest in research that endeavours to conceal data in a covert and stealth manner, to avoid detection through the embedment of the secret data into cover images that appear inconspicuous. These cover images may be in the format of images or videos used for concealment of the messages, yet still retaining the quality visually. Over the past ten years, there have been numerous researches on varying steganographic methods related to images, that emphasised on payload and the quality of the image. Nevertheless, a compromise exists between the two indicators and to mediate a more favourable reconciliation for this duo is a daunting and problematic task. Additionally, the current

... Show More
Publication Date
Thu Sep 01 2022
Journal Name
Computers And Electrical Engineering
Automatic illness prediction system through speech
...Show More Authors

View Publication
Scopus (6)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Tue Feb 20 2024
Journal Name
Arab Gulf Journal Of Scientific Research
Investigation of Pseudomonas aeruginosa bacteria in a number of Baghdad schools and extent of their resistance to disinfectants and sterilizers
...Show More Authors

Purpose This study was design to investigate of Purpose This study was design to investigate of P. aeruginosa, an example of Gram-negative bacteria, in seven primary and secondary schools of Baghdad city, and the effects of Ethanol and Dettol of P. aeruginosa biofilm. Design/methodology/approach Seventy swabs were collected from seven primary and secondary schools of Baghdad city, Iraq, during November -December 2022. Swabs were collected from classes desk, doors handles, students hands and water taps. Standard microbiological testing methods were used on the samples for isolation and identification. The ability of bacteria to form biofilm and the effects of Ethanol and Dettol on “preformed” biofilms was examined by microtiter plate wi

... Show More
Scopus
Publication Date
Wed Dec 30 2009
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Mass Transfer Correlations for a Rotating Cylinder Electrode under lsothermal and Controlled Heat Transfer Condition
...Show More Authors

Mass transfer correlations for iron rotating cylinder electrode in chloride/sulphate solution, under isothermal and
controlled heat transfer conditions, were derived. Limiting current density values for the oxygen reduction reaction from
potentiostatic experiments at different bulk temperatures and various turbulent flow rates, under isothermal and heat
transfer conditions, were used for such derivation. The corelations were analogous to that obtained by Eisenberg et all
and other workers.

View Publication Preview PDF
Publication Date
Tue Sep 01 2020
Journal Name
Journal Of Engineering
Experimental Study on Heat Transfer and Flow Characteristics in Subcooled Flow Boiling in a Microchannel
...Show More Authors

The current study presents an experimental investigation of heat transfer and flow characteristic for subcooled flow boiling of deionized water in the microchannel heat sink. The test section consisted of a single microchannel having 300μm wide nominal dimensions and 300μm height (hydraulic diameter of 300μm). The test section formed of oxygen-free copper with 72mm length and 12mm width. Experimental operation conditions spanned the heat flux (78-800) kW/m2, mass flux (1700 and 2100) kg/m2.s at 31˚C subcooled inlet temperature. The boiling heat transfer coefficient is measured and compared with existing correlations. Also, the experimental pressure drop is measured and compared with microscale p

... Show More
View Publication Preview PDF
Crossref (1)
Crossref