In this work, varying compositions of SiO2 micro filler were added
with the Polyvinyl Chloride (PVC) and samples have been prepared
using film casting technique. The results have been analyzed and
compared for PVC samples with (1 wt%, 3 wt%, 5 wt% and 10 wt%)
SiO2 micro filler. Mechanical characteristics such as tensile strength,
elongation at break and Young`s modulus were measured for all the
samples, where the tensile strength was increased from 8.39 Mpa for
purified PVC to 16 Mpa for 3% SiO2/PVC composite. Also, thermal
conductivity measurement values illustrated that composite materials
have a good thermal insulation at 10 wt. %, thermal conductivity was
decreased from 0.1684 W/m. K for PVC to 0.1310W/m. K at 10%
SiO2/PVC composite. Absorptivity test was also carried out for these
samples, the results of this study proved that PVC and SiO2-PVC
composites have low diffusion coefficients ranging from (10-13- 10-10
m2/s). Similarly, the dielectric properties like dielectric constant, loss
factor, resistance, and volume resistivity were performed; the
dielectric constant was increased from 2.1039 for PVC to 3.658 for
3% SiO2/PVC composites, while the dielectric loss factor was
decreased from 0.0144 for PVC to 0.0137 for 5%SiO2/PVC
composite. The values of resistance were increased from
17259.99(Ω) for purified PVC to 29185.75(Ω) for 10% SiO2/PVC
composites. Volume resistivity was increased from 0.3794 x109 (Ω.
cm) for PVC to 0.5179x109 (Ω. cm) for 10% SiO2/PVC composites.
FTIR spectroscopy was employed for all PVC-composite samples
and its results were investigated, there are systematic increases in
absorbance intensity spectra with SiO2 ratios attributed to good
distribution of inorganic fillers (Symmetric increases). The
microstructure and morphology of the prepared samples were
investigated by using optical microscope. It can be observed that, the
samples with (3% SiO2/PVC) are glossy and smooth without
agglomeration of (SiO2) particles in (PVC) matrix. The results
demonstrate that PVC-composite films prepared in this study show
promising potential to achieve good materials for plastic packaging
applications.
In this paper, magnesium oxide nanoparticles (MgO NPS) have been prepared and characterized and its concentration effect has been studied on polymers surface (MgO NPS). The results showed that the degradation of poly methyl methacrylate increased when using such metal oxide. The results also showed that the metal oxide increased the degradation of poly methyl methacrylate. X-ray diffraction, scanning electron microscopy, atomic force microscopy were used to study the morphological characteristics and size of nano MgO particles analysis. Films were prepared by mixing the different masses of MgO NPS (0.025, 0.05, 0.1, 0.2 and 0.4) % with a polymer solution ratio (W/V) 7 %. Photo-
... Show MoreIn this work polymeric composites were done from unsaturated polyester as a matrix reinforced with glass fiber type (E-glass) with two different volume fraction 20% & 40%. Fatigue tests showed that the number of fatigue cycles to failure limit for samples reinforced with uniform (woven Roving 0-90°) E-glass fiber and random (continuous fibers) with volume fraction 40% more than that for the same samples with volume fraction 20%. Also the fatigue results showed that the uniform samples failed with fatigue cycles more than that of random.
Background:The technology of nanoparticles has been expanded to many aspects of modern life. Titanium dioxide nanoparticles were of many nanomaterials utilized in biomedical applications. The interactions between nanoparticles and proteins are believed to be the base for the biological effect of the nanoparticles. The oxidation reaction of many substances is catalyzed by oxidizing enzymes called peroxidases. The activity of salivary peroxidase is elevated with periodontal diseases. the aim ofthis study is to examine the action of titanium dioxide nanoparticles on salivary peroxidase activity.Material and method75 participants were enrolled in this study—Periodontitis group with 44 participants and the non-periodontitis group with 31 pa
... Show MoreThe study aims to measure the impact of reporting on value creation on the earnings quality of the economic unit by presenting and discussing the conceptual aspects of the value creation process through multi-capital and the importance of reporting it in Iraqi private banks in addition to presenting and analyzing the concept of profit quality and its measurement models. Therefore, the checklist prepared for this purpose was used based on previous studies related to the subject in order to determine the level of reporting of the research sample banks by analyzing the content of the annual reports of those banks as well as adopting the Tobin's Q scale to measure the value of the economic unit and then using some statistical models to
... Show MoreBackground: The microhardness of a composite resin is a vital parameter that is used to determine its clinical behavior. Measuring the microhardness of a composite resin has been used as an indirect method to assess its degree of conversion and extent of polymerization. The purpose of this in vitro study was to evaluate the effect of three curing distances (0, 2, and 4 mm) on the microhardness of the top and bottom surfaces of three types of flowable bulk-fill composite resins (smart dentin replacement, Opus bulk fill flow, and Tetric N). Material and method: Sixty-three specimens from the three types of composite resins (n=21) were fabricated using Teflon mold with a 4mm depth and a 5 mm internal diameter and cured for 20 seconds. For e
... Show MoreThis article examines and proposes a dietary chain model with a prey shelter and alternative food sources. It is anticipated that mid-predators' availability is positively correlated with the number of refuges. The solution's existence and exclusivity are examined. It is established that the solution is bounded. It is explored whether all potential equilibrium points exist and are locally stable. The Lyapunov approach is used to investigate the equilibrium points' worldwide stability. Utilizing a Sotomayor theorem application, local bifurcation is studied. Numerical simulation is used to better comprehend the dynamics of the model and define the control set of parameters.
Objectives To compare the clinical efficacy of microvascular decompression surgery (MVD) and gamma knife radiosurgery (GKR) as a treatment for patients with primary trigeminal neuralgia (TN) and evaluate the outcome regarding pain relief, recurrence, and complications with both modalities of treatment. Patients and Methods A randomized prospective study conducted in SaadAlwitry Neurosciences Hospital, Baghdad, Iraq. Eighty-four patients with TN from January 2016 to January 2018, 45 patients had GKR while 39 patients treated with MVD. The pain evaluated pre-and post-operatively using the Barrow Neurological Institute Pain Intensity scale (BNIPI), visual analog scale (VAS) and Brief Pain Inventory Facial (BPI-Facial) scoring systems. In GKR p
... Show MoreObjective: The aim of this study is to find out the impact of life events upon onset of depression, to describe the
prevalence of life events among depressed patients.
Methodology: Retrospective a case-control study conducted in AL-Diwanyia Teaching Hospital, Psychiatric
Department on A non-probability (purposive sample) of (60) depressed patients and (60) of healthy person were matched
with them from general population. The data were collected through the use of semi-structured interview by
questionnaire, which consists of two parts (1) divide, section A. cover letter and B. Sociodemographic data which consists
of 9-items, (2) Life events questionnaire consists of 51-items distributed to six dimensions include, family
Background: Alveolar ridge expansion is proposed when the alveolar crest thickness is ≤5 mm. The screw expansion technique has been utilized for many years to expand narrow alveolar ridges. Recently, the osseodensification technique has been suggested as a reliable technique to expand narrow alveolar ridges with effective width gain and as little surgical operating time as possible. The current study aimed to compare osseodensification and screw expansion in terms of clinical width gain and operating time. Materials and methods: Forty implant osteotomies were performed in deficient horizontal alveolar ridges (3–5 mm). A total of 19 patients aged 21–59 years were randomized into two groups: the screw expansion group, which invo
... Show More: The aim of this research is to investigate the impact of Woods ' strategy in collecting second graders average for physics. To achieve the objective researcher coined the following hypothesis: there was no statistically significant difference at a level (0.05) between the average grades of the experimental group students studying physics as Woods and strategy between the average control group students who are studying the same article in the regular way. Test collection. Search sample amounted to (83) students and (42) students for the experimental group, and (41) students for the control group. Students were subjected to test experiment is composed of (30) after the completion of the experiment. And use appropriate statistical methods re
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