The products of composites material are very sesetive to many variables, such as manufacturing process, additive materials, …. etc. Filler or additive plays a major role to determine the formation of the properties and behavior of the composites. In this study, polyethylene terephthalate-based compounds were produced and characterized. The work is concerned to prepare samples of Polyethylene terephthalate (PET) - zinc-ferrite (ZnFe2O4) with different addition ratio as zinc-ferrite (1, 2, 5, 10, 15 and 20) wt% obtained from mixing the solution with a hot pressing method applied under optimum conditions. The densities of the composites for all samples were calculated. Through the work the diffusion of zinc-ferrite into the grain of Polyethylene terephthalate has been noted. Structural properties are studied by using X-ray powder pattern, the results of the XRD diffraction analysis showed that the structure for pure PET has four broad peaks at the (2θ=16.46°,17.45°, 22.72°,25.98°). The non-crystalline behavior of the polymer and the ceramic compound indicates the presence of a crystalline phase with a single cubic structure with a space group fd-3m (227)) (a=b=c=8.44 Å, V=601.45 (Å)³). While adding zinc-ferrite to PET in different concentrations to obtain (PET / ZnFe2O4) composites material will increase the intensity of the X-ray peaks, and change the location of the peaks with the addition of zinc-ferrite. It is noted that X-ray diffraction patterns for PET / ZnFe2O4 (20%) indicates that there was no apparent variation of the patterns of pure Zn-ferrite ceramic diffraction which showed that the crystalline structure remains stable in PET / ZnFe2O4. In addition, the electrical properties of the compounds represented by the dielectric constant (real and imaginary), dielectric loss ( tanδ) and the A.C conductivity as a function of a range of frequencies (50Hz-1MHz) have been measured. The results indicated that these properties increase with increasing concentrations of ceramic addition. On the other hand, these properties decrease with increasing frequency due to the change in polarization mechanisms. It has been proven that these prepared superposed materials possess good stability properties in a wide range of frequencies, making these polymeric overlays of wide use in many applications. As for the measurements of Shore D hardness, it has been shown that the hardness of the compounds increases with increasing ceramic concentrations.
The present study was undertaken to study the effect of apigenin and luteolin on physiological and histological changes in rats treated with cytarabine drugs. Thirty-five albino healthy male adult rats with equal age weighing 250 -300g were enrolled. Rats were randomly divided into seven groups according to the treatment. Group “1” was treated with normal saline and served as the control group. Groups “2,3 and 4” received cytarabine, apigenin, and luteolin respectively, while groups 5, 6, and 7 received a combination of “apigenin + cytarabine”, “luteolin + cytarabine”, and “apigenin + luteolin + cytarabine”, respectively. After one week of treatment, all seven groups of rats were
... Show MoreAims: This study was done to investigate the effect of low energy laser therapy on bone healing at the extraction site. Materials and methods:(24) male albino rats were exposed to the extraction procedure of the maxillary first molar on the first day of a seven day experiment and these animals were divided into two main groups; the control group and the laser group. The laser experiment involved using (Ga-As infrared diode laser) from optodent by directing the probe over the extraction site. The control group consisted of 4 rats, and the laser group was subdivided into 5 subgroups of 4 rats each. The laser dose was as follows: B1: a single dose of 5 minutes immediately after extraction.,
... Show MoreThe study aims to indicate the role of the mechanisms and principles of corporate governance in the activation of social responsibility reports, and increase disclosure, to achieve sustainability, legitimacy, and integrity of the business. Through the presentation of the conceptual framework for corporate governance and social responsibility, identify the key dimensions of social responsibility and the statement of the relationship between the mechanisms of governance and social responsibility reports in accordance with these dimensions. To prove the hypothesis research has selected a sample of listed companies in the Iraqi market for securities,
... Show MoreObjective(s): The world of dentistry is constantly evolving, and with the advent of 3D printing technology, the possibilities are endless. However, little is known about the effects of adding ZrO2 NPs to the denture base resin of 3D additive manufacturing technique.Aim of this study is to evaluate the behavior of resin which is used to 3D printing of denture base with the addition of ZrO2 NPs on denture adaptation property and diametral compression strength.Methods: 60 samples were printed, 30 disks for diametral compressive test and 30 denture base for denture adaptation test. Three groups per test (n=10). The control group for each test included unreinforced 3Dprinted denture base resin, and the other groups were reinforced with (2&
... Show MoreObjectives: to compare health of mothers and neonatal among age groups, to find out the correlation between
age groups and mother and neonatal health.
Methodology: A descriptive study was carried out at delivery rooms of three teaching hospitals in Baghdad city
from Feb. 28th through May. 28th
, 2013. A purposive (non-probability) sample of 300 laboring women was selected
from delivery rooms categorized into three groups, group 1 (≤19) years, group 2 their age between (20-35) years
old and group 3 their age (≥35) years. The data were collected through the use of constructing questionnaire, an
interview technique with mothers and reviewing their medical records as means of data collection; The
questionnaire con
The CdSe pure films and doping with Cu (0.5, 1.5, 2.5, 4.0wt%) of thickness 0.9μm have been prepared by thermal evaporation technique on glass substrate. Annealing for all the prepared films have been achieved at 523K in vacuum to get good properties of the films. The effect of Cu concentration on some of the electrical properties such as D.C conductivity and Hall effect has been studied.
It has been found that the increase in Cu concentration caused increase in d.c conductivity for pure CdSe 3.75×10-4(Ω.cm)-1 at room temperatures to maximum value of 0.769(Ω.cm)-1 for 4wt%Cu.All films have shown two activation energies, where these value decreases with increasing doping ratio. The maximum value of activation energy was (0.319)eV f
Breast cancer is one of the most important malignant diseases all over the world. The incidence of breast cancer is increasing around the world and it is still the leading cause of cancer mortality An Approximately 1.3 million new cases were diagnosed worldwide last year. With areas rising increasing, risk factors for breast cancer including obesity, early menarche, alcohol and smoking, environmental contamination and reduced or late birth rates become more prevalent. In Iraq, breast cancer ranks first among types of cancers diagnosed in women. This study was conducted on one hundred twenty women with breast cancer that was evaluated and investigated for the possible role of the risk factors on the development of breast cancer in females. T
... Show MoreWhen optimizing the performance of neural network-based chatbots, determining the optimizer is one of the most important aspects. Optimizers primarily control the adjustment of model parameters such as weight and bias to minimize a loss function during training. Adaptive optimizers such as ADAM have become a standard choice and are widely used for their invariant parameter updates' magnitudes concerning gradient scale variations, but often pose generalization problems. Alternatively, Stochastic Gradient Descent (SGD) with Momentum and the extension of ADAM, the ADAMW, offers several advantages. This study aims to compare and examine the effects of these optimizers on the chatbot CST dataset. The effectiveness of each optimizer is evaluat
... Show MoreBackground: The aim of the study was to evaluate the amount of changes in the horizontal and vertical maxillary arch dimensions measurements following the premature loss of primary molars. Materials and methods: The sample consist of (50) children with unilateral prematurely extracted either first or second primary molars at the mixed dentition stage. Results and Conclusions: Results shows that there was an increase in the vertical incisor to canine distance (A) with both premature loss of first & second primary molars due to distal movement of primary canines and at the same time there were a significant loss of space in the extraction space with premature loss of second primary molar due to a mesial movement of maxillary first permanent
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