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alkej-676
Wear Behavior Performance of Polymeric Matrix Composites Using Taguchi Experiments
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This research estimates the effect of independent factors like filler  (3%, 6%, 9%, 11% weight fraction), normal load (5N, 10N, 15N), and time sliding (5,7 , 9 minutes) on wear behavior of unsaturated polyester resin reinforced with jute fiber and waste eggshell and, rice husk powder composites by utilizing a statistical approach. The specimens polymeric composite prepared from resin unsaturated polyester filled with (4% weight fraction) jute fiber, and (3%, 6%, 9%, 11% weight fraction) eggshell, and rice husk by utilizing (hand lay-up) molding. Dry sliding wear experiments were carried utilizing a standard (pin on disc test setup) following a well designed empirical schedule that depends on Taguchi’s experimental design L9 (MINITAB 16) with the determined (S/N) ratio and analysis of different (ANOVA) optimal factors to minimize the wear rate. Results exhibit that the presence the of 11% weight fraction eggshell and rice husk powder with 4% weight fraction jute fiber improves the wear resistance of unsaturated polyester composite materials significantly. The filler content was observed to be the major significant factor influencing the wear rate followed by time sliding and normal load. From the results of the S/N ratio, the optimization of wear parameters is obtained at specimens A3, A6, A7, and A10 as to minimize wear rate.

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Publication Date
Fri Oct 25 2013
Journal Name
International Endodontic Journal
Fabrication and characterization of polymer composites for endodontic use
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Aim To develop a low-density polyethylene–hydroxyapatite (HA-PE) composite with properties tailored to function as a potential root canal filling material. Methodology Hydroxyapatite and polyethylene mixed with strontium oxide as a radiopacifier were extruded from a single screw extruder fitted with an appropriate die to form fibres. The composition of the composite was optimized with clinical handling and placement in the canal being the prime consideration. The fibres were characterized using infrared spectroscopy (FTIR), and their thermal properties determined using differential scanning calorimetry (DSC). The tensile strength and elastic modulus of the composite fibres and gutta-percha were compared, dry and after 1 month storage in

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Publication Date
Sun Jun 03 2012
Journal Name
Baghdad Science Journal
Mechanical properties of carbon nanotube reinforced Epoxy Resin composites
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Overlapped have been prepared from epoxy resin material added to carbon Nanotube and percentages weight (0.1, 0.05, 0.01) % Studied the mechanical properties of the composite (bending, tensile an d hardness) has been found that the Flexural and tensile modulus of the composites were higher than the pure epoxy resin this may be due to the high mechanical strength of carbon nano tube (CNT). The hardness of the epoxy carbon Nanotube composites increased and the reason is due to increased overlap and stacking between the additives and material basis, which reduces the movement of polymer molecules leading to increased resistance to scratching material and cutting, will become more resistance to plastic deformation.

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Publication Date
Wed Dec 20 2017
Journal Name
Materials Science-poland
Preparation and electrical properties of polyimide/carbon nanotubes composites
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Abstract<p>Polyimide/MWCNTs nanocomposites have been fabricated by solution mixing process. In the present study, we have investigated electrical conductivity and dielectric properties of PI/MWCNT nanocomposites in frequency range of 1 kHz to 100 kHz at different MWCNTs concentrations from 0 wt.% to 15 wt.%. It has been observed that the electrical conductivity and dielectric constants are enhanced significantly by several orders of magnitude up to 15 wt.% of MWCNTs content. The electrical conductivity increases as the frequency is increased, which can be attributed to high dislocation density near the interface. The rapid increase in the dielectric constant at a high MWCNTs content can be explained by the form</p> ... Show More
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Publication Date
Mon Dec 31 2012
Journal Name
Al-khwarizmi Engineering Journal
Speech Compression Using Multecirculerletet Transform
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Compressing the speech reduces the data storage requirements, leading to reducing the time of transmitting the digitized speech over long-haul links like internet. To obtain best performance in speech compression, wavelet transforms require filters that combine a number of desirable properties, such as orthogonality and symmetry.The MCT bases functions are derived from GHM bases function using 2D linear convolution .The fast computation algorithm methods introduced here added desirable features to the current transform. We further assess the performance of the MCT in speech compression application. This paper discusses the effect of using DWT and MCT (one and two dimension) on speech compression. DWT and MCT performances in terms of comp

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Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
The use of two indicators of market value-added and return on capital invested in measuring the performance of the Iraqi banking sector
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For a long time, the intensification of profit represented a major goal for the company management ,but this goal confirmed a series of restrictions such the constriction on short period, the time rather than on long and medium strategic goal, the relationships with customers ,the supplies, employees , This goal is replaced by another one (intensification of the company's value) ,and the fortune of the share holders itself ,for the purpose  of creating value, the company must generate  great outcomes to cover the operating expense and to insure the a suitable compensation to the invested capital (the market value added) is  the indication used to estimate the company ability to create value –added the development

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Publication Date
Thu Apr 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of organizational stress on the Performance of professor at the Faculty of Economics and Commercial Sciences / University of Djelfa / Algeria
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The present study aims at identifying the effect of organizational pressure with its aspects (management, work team, nature and conditions of work, external environment) on job performance in all its dimensions (commitment and effort made, capabilities and the rapidity of performance, motivation and job satisfaction, work environment) for the university teacher at the Faculty of Economics, Commercial and Management Sciences at the University of Djelfa, Algeria.

     In this research, the descriptive analytical approach is used. Data was collected through the distribution of a questionnaire to a sample that included 130 permanent teachers before being analyzed using the (SPSS) statisti

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Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Encoding of QC-LDPC Codes of Rank Deficient Parity Matrix
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The encoding of long low density parity check (LDPC) codes presents a challenge compared to its decoding. The Quasi Cyclic (QC) LDPC codes offer the advantage for reducing the complexity for both encoding and decoding due to its QC structure. Most QC-LDPC codes have rank deficient parity matrix and this introduces extra complexity over the codes with full rank parity matrix. In this paper an encoding scheme of QC-LDPC codes is presented that is suitable for codes with full rank parity matrix and rank deficient parity matrx. The extra effort required by the codes with rank deficient parity matrix over the codes of full rank parity matrix is investigated.

 

 

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Publication Date
Sun Jun 01 2014
Journal Name
مجلة كلية مدينة العلم الجامعة
Palynological study for nine cultivated species of Asteraceae family
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The current research included palynological study for nine ornamental cultivated species of Asteraceae family. The study included measurement the dimensions of pollen grains and there shape in polar view and equatorial view, sculpturing,colpi length and width, spines length and number of spines rows between colpiand exine thickness, the study showed variations in pollen grains characters forthe studied taxa

Publication Date
Wed Dec 31 2014
Journal Name
Complex Metals
Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties
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New biscarboxylato zwitterionic ligands, namely bis(N-carboxylatoethyl)-4,4 -dipyridinum) L1 and bis(Ncarboxylatopropyl)-)-4,4 -dipyridinum) L2, were synthesized from the reaction of 4,4 -dipyridine with 3-bromopropanoic acid and 4-bromobutanoic acid, respectively. The reaction of these ligands and the azido coligand with some metal ions resulted in the formation of polymeric complexes of general formulae [Cr2(Ln)(N3)4]Cl2·H2O and [M2(Ln)(N3)4] xH2O, where (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); n = 1, 2; x = 1, 1, 1, 1, 0, 1, and 1, respectively.) The oxygens of the carboxylato group are coordinated to the metal ion in a bidentate fashion. The mode of bonding and overall geometry of the complexes were determin

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Publication Date
Fri Jan 01 2016
Journal Name
Al-ustath Journal For Human And Social Sciences
Infinitive Clauses as Matrix Verbs Complementationi in Shakespeare
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The aim of this research is to find out why some matrix verbs are no longer complemented by the two types of infinitive clauses as it is the case in Elizabethan English . At that time (when Shakespeare was writing ), the same matrix verb triggers the two types of infinitive clauses as its complex transitive complementation .Such free variation is not possible in Present –Day English . In this corpus – based study , it is shown that the choice of the form of the infinitive clause is not free; there are certain syntactic ,sem- antic constraints that dete, - infinitive.

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