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.
Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connection
... Show MoreThe nanostructured MnO2 /carbon fiber (CF) composite electrode was prepared using the anodic electrodeposition process. The crystal structure and morphology of MnO2 particles were determined with X-ray diffraction and field-emission scanning electron microscopy. The electrosorptive properties of the prepared electrode were investigated in the removal of cadmium ions from aqueous solution, and the effect of pH, cell voltage, and ionic strength was optimized and modeled using the response surface methodology combined with Box–Behnken design. The results confirm that the optimum conditions to remove Cd(II) ions were: pH of 6.03, a voltage of 2.77 V, and NaCl concentration of 3 g/L. The experimental results showed a good fit for the Freundli
... Show MoreThe dependence of the energy losses or the stopping power for the ion contribution in D- T hot plasma fuels upon the corresponding energies and the related penetrating factorare arrive by using by a theoretical approximation models. In this work we reach a compatible agreement between our results and the corresponding experimental results.
The aim of the research is to shed light on identifying the extent of the university professor's competencies and their roles in managing and training participants in e-training workshops as a pedagogical point view. The research sample consisted of a group of (30) university professors (lecturers) in the training workshops, in scientific,humanitarian and social disciplines, including (12) a university professor (holding a trainer certificate), , the research methodology is descriptive, and the community is a group of trained participants. (115) participated in (40) e-training workshops organized by the Center for Continuing Education at the University of Baghdad (and the selection of workshops within the researcher's specialization in the
... Show Moreلطالما كان انتظار الملأ للخلاص والتي ترتبط بشكل اساسي بال "منتظر" او ال "مخلص" جزءا من الوعي الجمعي الذي تطور ليكون مرتبطا بالنمط البدائي والذي بدوره أصبح مرآةً تنعكس على اساسها فرص الانسان نحو النجاة. في مسرح القرن العشرين, لم تنفك فكرة الانتظار ان ترتبط بمسرحية صاموئيل بيكيت العبثية " في انتظار غودو" كونها مثالا رمزيا بالرغم من انه تجسيد شخصية "غودو" وقعت تحت وطأة الكثير من عمليات التحوير والتغيير في اطاره
... Show MoreVarious theories have been proposed since in last century to predict the first sighting of a new crescent moon. None of them uses the concept of machine and deep learning to process, interpret and simulate patterns hidden in databases. Many of these theories use interpolation and extrapolation techniques to identify sighting regions through such data. In this study, a pattern recognizer artificial neural network was trained to distinguish between visibility regions. Essential parameters of crescent moon sighting were collected from moon sight datasets and used to build an intelligent system of pattern recognition to predict the crescent sight conditions. The proposed ANN learned the datasets with an accuracy of more than 72% in comp
... Show MorePolyaromatic hydrocarbons (PAHs) are a group of aromatic compounds that contain at least two rings. These compounds are found naturally in petroleum products and are considered the most prevalent pollutants in the environment. The lack of microorganism capable of degrading some PAHs led to their accumulation in the environment which usually causes major health problems as many of these compounds are known carcinogens. Xanthene is one of the small PAHs which has three rings. Many xanthene derivatives are useful dyes that are used for dyeing wood and cosmetic articles. However, several studies have illustrated that these compounds have toxic and carcinogenic effects. The first step of the bacterial degradation of xanthene is conducted by d
... Show MoreEmotional blackmail is generally defined as manipulating others' emotions for personal gain. It is a type of manipulation that damages healthy relationships among people and turns them into toxic relations leaving the victim in a state of depression and under stress of losing something s/he holds dear. This study aims to identify the pragmatic techniques of emotional blackmail used by both blackmailers and victims in "No One Would Tell" (2018). To do so, the researchers developed an eclectic model comprising Forward and Frazier's (1997) emotional blackmail, Searle’s speech acts (1979), Brown and Levinson’s politeness strategies (1987), Culpeper’s impoliteness strategies (1996, 2005), and Mayfield's taxonomy of fallacy (2007)
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