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Numerical Study of Heat Transfer Enhancement in Heat Exchanger Using AL2O3 Nanofluids
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In this study, the flow and heat transfer characteristics of Al2O3-water nanofluids for a range of the Reynolds number of 3000, 4500, 6000 and 7500 with a range of volume concentration of 1%, 2%, 3% and 4% are studied numerically. The test rig consists of cold liquid loop, hot liquid loop and the test section which is counter flow double pipe heat exchanger with 1m length. The inner tube is made of smooth copper with diameter of 15mm. The outer tube is made of smooth copper with diameter of 50mm. The hot liquid flows through the outer tube and the cold liquid (or nanofluid) flow through the inner tube. The boundary condition of this study is thermally insulated the outer wall with uniform velocity at (0.2, 0.3, 0.4 and 0.5 m/s) at the cold loop and constant velocity at (0.5 m/s) at the hot loop.

The results show that the heat transfer coefficient and Nusselt number increased by increasing Reynolds number and particle concentration. Numerical results indicate that the maximum enhancement in Nusselt number and heat transfer coefficient were 9.5% and 13.5% respectively at Reynolds number of 7100 and particles volume fraction of 4%. Results of nanofluids also showed a good agreement with the available empirical correlation at particles volume fractions of 1%, 2% and 3%, but at volume fractions of 4% a slight deviation is obtained.

 

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Publication Date
Tue Jan 01 2019
Journal Name
Ieee Access
Speech Enhancement Algorithm Based on Super-Gaussian Modeling and Orthogonal Polynomials
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Publication Date
Sat Jan 01 2022
Journal Name
Technologies And Materials For Renewable Energy, Environment And Sustainability: Tmrees21gr
Theoretical investigation of charge transfer at N3 sensitized molecule dye contact with TiO2 and ZnO semiconductor
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We present a simple model of charge transfer current through sensitizer N3 molecule contact to TiO2 and ZnO semiconductors to calculate the charge transfer current. The model underlying depends on the fundamental parameters of the charge transfer reaction and it is based on the quantum transition theory approach. A transition energy, driving energy and potential barrier have been taken into account charge transfer current at N3 / TiO2 and N3 / ZnO devices with wide polarity solvents Acetic acid, 2-Methoxyethanol, 1-Butanol, Methyl alcohol, chloroform, N,N-Dimethylacetamide and Ethyl alcohol via the quantum donor-acceptor system.The effects of the transition energy and potential barrier are computed and discussion on charge transfer current.

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Publication Date
Sat Sep 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Effect Of Solvent Types On Photo Induced Electron Transfer in Methylene Blue dye MB+-- Benzophenone Ketone (ABP) System..
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Th   r:ats for the photo induced eleytr-on tra;nsfer reactions in the

Methylen-e blue 'l'vffi+ ·dye· with benzo_phenone (ABP) ketone in variety

solvc;:nts al n:loin tempemtme ha;ve qn calculated . Electron trans_ fer

-rates are large in• }stt:on;gly--'{:'lolaf- solvent and week in-l s.s :polar solvent.

the high values o:E   t±te r.tes a_f electro-n  tr;ans-fer indicate that tite dye

triplet i$ mqre, r activ.e toWard ABP ket-one.

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Publication Date
Fri Mar 30 2012
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Enhancement of Biogas production and organic reduction of sludge by different pre-treatment processes
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Anaerobic digestion (AD) is the most common process for dealing with primary and secondary wastewater sludge. In the present work, four pre-treatment methods (ultrasonic, chemical, thermal, and thermo-chemical) are investigated in Al-Rustumya Wastewater Treatment plant in order to find their effect on biogas production and volatile solid removal efficiency during anaerobic digestion.
Two frequencies of ultrasonic wave were used 30 KHz and 50 KHz during the pre-treatment. Sodium hydroxide was added in different amounts to give three pH values of 9, 10 and 11 in chemical pre-treating processes. The sludge was heated at 60oC and 80oC through thermal pre-treatment experiment. Also, the sludge was treated thermo-chemically at 80 oC and pH

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Publication Date
Sat Dec 01 2018
Journal Name
Al-khwarizmi Engineering Journal
Experimental and Numerical Investigation for Simulation of Thermophysical Properties for Polypropylene 575 Polymer Melts in Single Screw Extruder
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A numerical model for Polypropylene 575 polymer melts flow along the solid conveying screw of a single screw extruder under constant heat flux using ANSYS-FLUENT 17.2 software has been conducted. The model uses the thermophysical properties such as Viscosity, thermal conductivity, Specific heat and density of polypropylene 575 that measured as a function of temperature, and residence time data for process simulation. The numerical simulation using CFD models for single screw extruder and the polymer extrusion was analysed for parameters such as (thermal conductivity, specific heat, density and viscosity) reveals a high degree of similarity to experimental data measured. The most important outcome of this study is that geometrical, parame

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Publication Date
Thu Nov 01 2018
Journal Name
International Journal Of Biomathematics
A non-conventional hybrid numerical approach with multi-dimensional random sampling for cocaine abuse in Spain
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This paper introduces a non-conventional approach with multi-dimensional random sampling to solve a cocaine abuse model with statistical probability. The mean Latin hypercube finite difference (MLHFD) method is proposed for the first time via hybrid integration of the classical numerical finite difference (FD) formula with Latin hypercube sampling (LHS) technique to create a random distribution for the model parameters which are dependent on time [Formula: see text]. The LHS technique gives advantage to MLHFD method to produce fast variation of the parameters’ values via number of multidimensional simulations (100, 1000 and 5000). The generated Latin hypercube sample which is random or non-deterministic in nature is further integ

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Publication Date
Tue Sep 01 2015
Journal Name
Journal Of Engineering
Experimental Study on the Effect of Using Metallic Brushes on the Charging and Discharging Time of Thermal Energy Storage Unit
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Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time

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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Numerical Simulation of The Influence of Geometric Parameter on The Flow Behavior in a Solar Chimney Power Plant System
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Numerical simulations have been carried out on the solar chimney power plant systems. This paper gives the flow field analysis for a solar chimney power generation project located in Baghdad. The continuity, Naver-stockes, energy and radiation transfer equations have been solved and carried out by Fluent software. The governing equations are solved for incompressible, 3-D, steady state, turbulent is approximated by a standard k -  model with Boussiuesq approximation to study and evaluate the performance of solar chimney power plant in Baghdad city of Iraq. The different geometric parameters of project are assumed such as collector diameter and chimney height at different working conditions of solar radiation intensity (300,450,600,750

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Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
(The role of strategices to manage the human resources in enhancement the process of knowledge management : Field Search in the Ministry of Transportation)
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The aims of the research is to know the role of strategic to manage the human resources in enhancement the process of knowledge management in the Ministry of Transportation , In addition to the effects occurred on outcomes for both the managers and practitioners .

For the purpose of achieving the objectives of the research , the researchers designed a questionnaire that included (40 Points for collecting the primary data from the sample of the research which contained (51) indiviluals. In light of that, the data was to collect and analyzed and hypotheses were tested by using the (SPSS) Program, and a number of statistical techniques was used to attain the goal of the research such as the means ,  Sta

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Publication Date
Fri Aug 28 2020
Journal Name
Iraqi Journal Of Science
Numerical Simulation of Immiscible CO2-Assisted Gravity Drainage Process to Enhance Oil Recovery
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The Gas Assisted Gravity Drainage (GAGD) process has become one of the most important processes to enhance oil recovery in both secondary and tertiary recovery stages and through immiscible and miscible modes.  Its advantages came from the ability to provide gravity-stable oil displacement for improving oil recovery, when compared with conventional gas injection methods such as Continuous Gas Injection (CGI) and Water – Alternative Gas (WAG). Vertical injectors for CO2   gas were placed at the top of the reservoir to form a gas cap which drives the oil towards the horizontal oil producing wells which are located above the oil-water-contact. The GAGD process was developed and tested in vertical wells to increase oil r

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