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Modifications of Polymers through the Addition of Ultraviolet Absorbers to Reduce the Aging Effect of Accelerated and Natural Irradiation
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The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers. Recently, polyphosphates, Schiff bases, and organometallic complexes were synthesized and used as potential ultraviolet absorbers for polymeric materials. They reduced the damage caused by accelerated and natural ultraviolet aging, which was confirmed by inspecting the surface morphology of irradiated polymeric films. For example, atomic force microscopy revealed that the roughness factor of polymers’ irradiated surfaces was improved significantly in the presence of ultraviolet absorbers. In addition, the investigation of the surface of irradiated polymers using scanning electron microscopy showed a high degree of homogeneity and the appearance of pores that were different in size and shape. The current work surveys for the first time the use of newly synthesized, ultraviolet absorbers as additives to enhance the photostability of polymeric materials and, in particular, polyvinyl chloride and polystyrene, based mainly on our own recent work in the field.

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Publication Date
Wed May 29 2019
Journal Name
Iraqi Journal Of Physics
Impact strength behaviour of PMMA denture base through addition of different nanoparticles after immersion in some nutrition liquids
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Poly methyl methacrylate PMMA polymer could be considered the main material that used mostly in the recent years in denture base fabrication. It commonly known by it is poor strength properties such as low impact strength. The aim of the present research was to enhance the performance of PMMA denture base through the addition of two kind of nanoparticles (nano particles that selected from artificial and natural sources). Nano -particles from both Al2O3 and crushed peanut Peel were used for comparing purposes.Various weight fraction used in this study for both kinds of the additive (1%, 2% and 3%). Moreover, in this work a study and evaluation in impact strength (I.S.) value were done before and after immersion. The new prepared nanocompo

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Publication Date
Fri Dec 15 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The Effect of Addition of Zirconium Nano Particles on Antifungal Activity and Some Properties of Soft Denture Lining Material
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Background Microorganisms and fungal growth especially Candida albicans, on soft denture lining material are the most common problem which can lead to chronic mucosal inflammation. The aim of this study was to evaluate the effect of zirconium nanoparticles into acrylic-based heat cured soft denture lining material against Candida albicans, and the amount of zirconium ion release of soft liner/ZrNPs composite. Furthermore, evaluate shear bond strength after ZrNPs addition to soft liner. Materials and methods: Zirconium nanoparticles were added into acrylic-based soft denture liner in various percentages (1%, and 1.5% by weight). Two hundred and fifty specimens were arranged and isolated into four groups as per the test to be done The antifu

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Publication Date
Wed Dec 14 2022
Journal Name
Civil Engineering Journal
Rutting Prediction of Hot Mix Asphalt Mixtures Modified by Nano silica and Subjected to Aging Process
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High-volume traffic with ultra-heavy axle loads combined with extremely hot weather conditions increases the propagation of rutting in flexible pavement road networks. Several studies suggested using nanomaterials in asphalt modification to delay the deterioration of asphalt pavement. The current work aims to improve the resistance of hot mix asphalt (HMA) to rutting by incorporating Nano Silica (NS) in specific concentrations. NS was blended into asphalt mixtures in concentrations of 2, 4, and 6% by weight of the binder. The behavior of asphalt mixtures subjected to aging was investigated at different stages (short-term and long-term aging). The performance characteristics of the asphalt mixtures were evaluated using the Marshall s

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Publication Date
Sat Apr 01 2023
Journal Name
Journal Of Engineering
Moisture Susceptibility of Hot Mix Asphalt Mixtures Modified by Nano Silica and Subjected to Aging Process
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Moisture damage is described as a reduction in stiffness and strength durability in asphalt mixtures due to moisture. This study investigated the influence of adding nano silica (NS) to the Asphalt on the moisture susceptibility of hot-mix-asphalt (HMA) mixtures under different aging conditions. NS was mixed with asphalt binder at concentrations of 2%, 4%, and 6% by weight of the binder. To detect the microstructure changes of modified Asphalt and estimate the dispersion of NS within the Asphalt, the field emission scanning electron microscope (FE-SEM) was used. To examine the performance of Asphalt mixed with NS at different aging stages (short-term and long-term aging), asphalt mixture tests such as Marshall stability,

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Publication Date
Sun Oct 20 2024
Journal Name
Engineering Reports
A Theoretical and Experimental Investigation of the Effects of Inverted Wings Modifications on the Stability and Aerodynamic Performance of a Sedan Car at Cornering
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ABSTRACT<p>This research examines the impact of cornering on the aerodynamic forces and stability of a Nissan Versa (Almera) passenger sedan car by introducing novel modifications. These modifications included single inverted wings with end plates as a front spoiler, double‐element inverted wings with end plates as a rear spoiler, and incorporating the ground as a diffuser under the car trunk. The goal is to enhance the performance and stability of conventional passenger cars. To ensure the accuracy of the numerical data, the study utilized multiple methodologies to model the turbulence model, ultimately selecting the most suitable option. This involved comparing numerical data with wind tunnel experimental d</p> ... Show More
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Publication Date
Sun Jun 30 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Proposed model for the work of audit committees in the public sector and its interaction with the Federal Board of Supreme Audit to reduce the incidents of fraud
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This growing interest of the international scientific specialized commissions is due to the role that the audit committee can play, as one of companies’ governance tools, to increase the accuracy and transparency of the financial information disclosed by the companies, through its oversight role on the process of preparing financial reports, its supervision on the internal audit function within the companies, and supporting its independency, as well as coordinating the efforts between the internal control unites and the external auditor represented by the (Board of Supreme Audit) to clear the observations and irregularities in order to reduce the fraud cases.

This research was built on an applied sample of audit committee works

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Publication Date
Wed Nov 28 2018
Journal Name
International Journal Of Engineering &amp; Technology
Improvement of Gypsum Soil by Using Polyurethane to Reduce Erosion and Solubility of Irrigation Canals
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The reducing of erosion and the solubility of irrigation canals soils which constructed on gypsum soil is important in civil and water resources engineering. The main problem of gypsum soils is the presence of gypsum which represents one of most complex engineering problems, especially when accompanied by the moving of water which represent dynamic load along the canal. There are several solutions to this problem, in this research “Poly urethane” is used to give the gypsum soil sufficient hardness to reduce the solubility and erosion, after compacting the soil in the canal, percentages of Poly urethane was used to making cover to the soil by mixing percent of soil with Poly urethane, and the ratio was as follows: (5 and 10) % an

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Publication Date
Mon Jan 01 2024
Journal Name
Baghdad Science Journal
Proposed Hybrid Cryptosystems Based on Modifications of Playfair Cipher and RSA Cryptosystem
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Cipher security is becoming an important step when transmitting important information through networks. The algorithms of cryptography play major roles in providing security and avoiding hacker attacks. In this work two hybrid cryptosystems have been proposed, that combine a modification of the symmetric cryptosystem Playfair cipher called the modified Playfair cipher and two modifications of the asymmetric cryptosystem RSA called the square of RSA technique and the square RSA with Chinese remainder theorem technique. The proposed hybrid cryptosystems have two layers of encryption and decryption. In the first layer the plaintext is encrypted using modified Playfair to get the cipher text, this cipher text will be encrypted using squared

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
The Use of Tea leaves Wastes to reduce Hexavalent Chromium Concentration in industrial Waste Water by Adsorption
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Abstract : A research was conducted to study the process parameters affecting hexavalent chromium Cr (VI) (carcinogenic compound) the removal percentage from the electrical industries company waste water that contain 88 mg/l of Cr (VI) concentration by adsorption onto tea wastes. Synthetic water with 88 mg/l Cr (VI) concentration was used. Several operation parameters affecting Cr (VI) removal efficiency were investigated, such as pH, initial Cr (VI) concentration, stirring time and tea wastes dose. The experimental results reveal that maximum Cr (VI) removal reached up to 94.26% at pH of 2, stirring time of 180 minute, tea wastes do

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Publication Date
Mon Oct 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Integration of Dissolved Analysis and Total Quality Management to reduce costs and improve product quality
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there is a need to use the teardown Technique in a various fields and different motives and used often by economic units as a technique to help other techniques for example, used by some economic units for the analysis of other economic units of products in order to work on the development of products and look for opportunities to improve product quality and avoid product errors competitor or reduce its costs, in addition to the services provided by quality control is used ISO 17025 integration with unassembled analysis to adjust the quality of the product by comparing the pieces produced with designed models that are also the product as a whole compared with the original design

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