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The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System
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Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Solving Optimal Control Linear Systems by Using New Third kind Chebyshev Wavelets Operational Matrix of Derivative
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In this paper, a new third kind Chebyshev wavelets operational matrix of derivative is presented, then the operational matrix of derivative is applied for solving optimal control problems using, third kind Chebyshev wavelets expansions. The proposed method consists of reducing the linear system of optimal control problem into a system of algebraic equations, by expanding the state variables, as a series in terms of third kind Chebyshev wavelets with unknown coefficients. Example to illustrate the effectiveness of the method has been presented.

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Publication Date
Sat Dec 11 2021
Journal Name
Engineering, Technology & Applied Science Research
Behavior of RC Beams Strengthened with NSM-CFRP Strips Subjected to Fire Exposure: A Numerical Study
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The use of Near-Surface Mounted (NSM) Carbon-Fiber-Reinforced Polymer (CFRP) strips is an efficient technology for increasing flexural and shear strength or for repairing damaged Reinforced Concrete (RC) members. This strengthening method is a promising technology. However, the thin layer of concrete covering the NSM-CFRP strips is not adequate to resist heat effect when directly exposed to a fire or at a high temperature. There is clear evidence that the strength and stiffness of CFRPs severely deteriorate at high temperatures. Therefore, in terms of fire resistance, the NSM technique has a significant defect. Thus, it is very important to develop a set of efficient fire protection systems to overcome these disadvantages. This pape

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Publication Date
Sun Sep 15 2019
Journal Name
Plant Archives
ANTIBACTERIAL ACTIVITY OF CONOCARPUS ERECTUS LEAVES EXTRACTS ON SOME MICROORGANISMS ISOLATED FROM PATIENTS WITH BURN INFECTION
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Medicinal plants are a source for a wide variety of natural active compounds and are used for the treatment of diseases throughout the world. Conocarpus erectus L. widely planted all over Iraq and has different secondary metabolites, which has been used in treatment of anemia, cancer, fever and diarrhea. The present study aims to estimate the antibacterial activity of Conocarpus erectus leaves extracts on some microorganisms collected from patients with burn infection. The study began with the collection of Conocarpus erectus leaves in June 2018 from the trees in university of Baghdad. Maceration method was used to prepare aqueous extract, while Soxhelt apparatus was used to prepare methanolic extract. The results of phytochemical test show

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Publication Date
Fri Jan 01 2021
Journal Name
Aip Conference Proceedings
Toxicity analysis of Ag/Au core/shell nanoparticles synthesizes via seed-growth on blood human components
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Publication Date
Wed Jun 29 2022
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Constructed Wetland Units Filled with Waterworks Sludge for Remediating of Wastewater Contaminated with Congo Red Dye
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The disposal of textile effluents to the surface water bodies represents the critical issue especially these effluents can have negative impacts on such bodies due to the presence of dyes in their composition. Biological remediation methods like constructed wetlands are more cost-effective and environmental friendly technique in comparison with traditional methods. The ability of vertical subsurface flow constructed wetlands units for treating of simulated wastewater polluted with Congo red dye has been studied in this work. The units were packed with waterworks sludge bed that either be unplanted or planted with Phragmites australis and Typha domingensis. The efficacy of present units was evaluated by monitoring of DO, Temperature, COD

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Publication Date
Thu Aug 01 2024
Journal Name
Advances In Science And Technology Research Journal
Power Predicting for Power Take-Off Shaft of a Disc Maize Silage Harvester Using Machine Learning
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Publication Date
Sun Jun 30 2024
Journal Name
Iraqi Journal Of Science
Detection of Zn Water Pollution by a Biosensor Based on Alkaloids Derived from Iraqi Catharanthus Roseus
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     In this work, the detection of zinc (Zn) ions that cause water pollution is studied using the CSNPs- Linker-alkaloids compound that was prepared by linking extracted alkaloids from Iraqi Catharanthus roseus plant with Chitosan nanoparticles (CSNPs) using maleic anhydride. This compound is characterized by an X-ray diffractometer (XRD) which shows that it has an orthorhombic structure with crystallite size in the nano dimension. Zeta Potential results show that the CSNPs-Linker-alkaloids carried a positive charge of 54.4 mV, which means it possesses high stability.  The Fourier transform infrared spectroscopy (FTIR) shows a new distinct band at 1708.93 cm-1 due to C=O esterification. Scanning electron microscope (SEM) image

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Robotics And Control (jrc)
Artificial Intelligence Based Deep Bayesian Neural Network (DBNN) Toward Personalized Treatment of Leukemia with Stem Cells
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The dynamic development of computer and software technology in recent years was accompanied by the expansion and widespread implementation of artificial intelligence (AI) based methods in many aspects of human life. A prominent field where rapid progress was observed are high‐throughput methods in biology that generate big amounts of data that need to be processed and analyzed. Therefore, AI methods are more and more applied in the biomedical field, among others for RNA‐protein binding sites prediction, DNA sequence function prediction, protein‐protein interaction prediction, or biomedical image classification. Stem cells are widely used in biomedical research, e.g., leukemia or other disease studies. Our proposed approach of

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Publication Date
Sat Feb 01 2020
Journal Name
Journal Of Water Process Engineering
Waterworks sludge-filter sand permeable reactive barrier for removal of toxic lead ions from contaminated groundwater
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Publication Date
Wed Mar 01 2023
Journal Name
Journal Of Ovonic Research
Effect of reduced graphene oxide hybridization on ZnO nanoparticles sensitivity to NO2 gas: A DFT study
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In the present work, a density functional theory (DFT) calculation to simulate reduced graphene oxide (rGO) hybrid with zinc oxide (ZnO) nanoparticle's sensitivity to NO2 gas is performed. In comparison with the experiment, DFT calculations give acceptable results to available bond lengths, lattice parameters, X-ray photoelectron spectroscopy (XPS), energy gaps, Gibbs free energy, enthalpy, entropy, etc. to ZnO, rGO, and ZnO/rGO hybrid. ZnO and rGO show n-type and p-type semiconductor behavior, respectively. The formed p-n heterojunction between rGO and ZnO is of the staggering gap type. Results show that rGO increases the sensitivity of ZnO to NO2 gas as they form a hybrid. ZnO/rGO hybrid has a higher number of vacancies that can b

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