Abstract : Silicone elastomer is widely used as the material of choice for fabricating maxillofacial prosthesis. However, silicone properties are far from ideal; low tear strength, low tensile strength and insufficient elasticity are the most undesirable properties. The purpose of this study was to evaluate the effect of addition of nano SiO2filler on tear strength, tensile strength, elongation at break, hardness and color of Cosmesil M-511 HTV maxillofacial silicone elastomer. Nano SiO2was added to the silicone base in concentrations of 4%, 5% and 6% by weight. Silicone with 0% nano filler served as a control. Tear test was done according to ISO 34-1. Tensile and elongation test was done according to ISO 37. Shore A hardness test was done according to ISO 7619. Visual color measurement test was done according to ASTM D1535. Scanning electron microscope was used to assess the efficiency of dispersing method. FTIR test was conducted to evaluate the interaction of nano SiO2with the silicone. Statistical analysis was done using one-way ANOVA and Fisher’s LSD test. SEM showed well dispersion of nano filler within the silicone matrix. FTIR indicated that nano SiO2interacted with the PDMS through its surface hydroxyl group. All nano SiO2concentration groups showed a highly significant increase in tear strength, tensile strength and elongation at break compared to the control group. The 5% group showed the highest mean values among other groups. Shore A hardness showed a highly significant increase with all nano SiO2concentrations with the increase being directly proportional to filler concentration increase. Spectrophotometer results showed a highly significant decrease in translucency of the material with all nano filler concentrations but this decrease in translucency was visually demonstrated as slight increase in color intensity. Reinforcement of M-511 silicone with 5% nano SiO2significantly improves all mechanical properties tested with a slight change of color seen visually.
This study has investigated the effect of jaundice on some
hematological and biochemical paramenters in male and female. The results have shown significant decrease in Hemoglobin concentration, packed cell volume, white blood cell count and platelet count. The biochemical parameters results have shown significant increase in prothrombine time, level of total bilirubin, Aspartale transminase and Alanin trans aminase in the serum of male and femal.
Ethanol production were evaluated by many strains with varing
degree of flocculation in fermentation medium of date extract withl 0
Brix, PHS in 30C0آ آ for آ 48hr.lt was found that ethanol production decrease with increase of flocculation degree and non-flocculant strain is آ more efficient in آ producing ethanol from flocculant strain,then
ethanol sensitivity were examined for the same strains, in liquid medium YE, it was found thatآ آ strain is more sensitive from nonآ flocculant and ethanol sensitivity depends upon flocculation degree.
Air pollution is one of the complex problems plaguing the environment at the present time
as a result of many liberation of gases, vapors and fumes of fuels and chemicals resulting
from industrial activities . It should be noted that there are some elements of the heavy
(Heavy Metals), including toxic in the air, with different concentrations in the air depending
on the nature of the area, for example be in rural areas is lower than in cities or industrial
areas as measured parts million (ppm ) or parts per billion (ppb). Some of these important
elements in the physiological processes and enzymatic organisms but become toxic and
Qatlhand-increase Tercisahaan the permissible limits Bhave nature ,The air contaminant
The present study is designed to reveal the effect of Voltarin drug on some genetic indicators such as mitotic index(MI) of bone marrow cells and chromosome aberrations(CA) .The Voltarin is one of non Steroidal Anti-inflammation drug .Three concentrations of Voltarin were used 1.6 , 2 , 2.5 mg/kg Albino mices (Mus musculus) were injected for 7 days then mitotic index (MI) was counted and chromosomal aberrations of bone marrow cells . The results could be summarized as follows : 1-The doses (1.6,2) mg/Kg showed no negative effects on&nbs
... Show MoreThe speed of skills has become linked to modern methods of individual and group play, and each of them has begun to serve the other tactically. Through the follow-up of the researchers, they noticed that there is a significant weakness in the speed of performance and slowness in mental preparation, which plays a major role in understanding mental readiness, which is linked to the speed of making decisions during the game, as well as the weakness of the physical speed of the female players, which in turn has an impact on the skill performance of the players of the Iraqi clubs, which are the main supporter of the national team. The study aimed to identify the effect of interactive speed training on the performance of some skills among
... Show MoreAir pollution is one of the complex problems plaguing the environment at the present time
as a result of many liberation of gases, vapors and fumes of fuels and chemicals resulting
from industrial activities . It should be noted that there are some elements of the heavy (Heavy
Metals), including toxic in the air, with different concentrations in the air depending on the
nature of the area, for example be in rural areas is lower than in cities or industrial areas as
measured parts million (ppm ) or parts per billion (ppb). Some of these important elements in
the physiological processes and enzymatic organisms but become toxic and Qatlhand-increase
Tercisahaan the permissible limits Bhave nature ,The air contaminant co
Lighting is a very important element of treatment if the color contains many imaging system (digital cameras) and the unit of light and the light within these units are not strong , but usefel when the light is low , in different lighting intensities conditions image quality will not persist good enough and image may become dark or slightly exposed to light which leads to lower the details in image where we can not modify contrast or light ness to compensate thr decrease without losing the light and dark deatials . So we went in this research to study the variation colored texts written on the painting and lighting cases of non –regular ( a few) and different distances . As the diversity of these texts written on the board a
... Show MoreBackground: Dental implants act as infrastructure for fixed restoration to look like as a natural tooth. Osseointegration is a biological events and considered as a base for success of dental implant. The aim of this study is to evaluate the bond strength between bone and Ti implant coated with mixture of nano hydroxyapatite-chitosan-collagen compared with Ti implants coated with nano hydroxyapatite implanted in rabbit tibia, after different period of implantation time (two and six weeks) by torque removal test. Material and methods: 36 screws of commercially pure titanium; 8mm in length and 3mm diameter , 18 screws coated with mixture of nano hydroxyapatite-chitosan-collagen and18 screws coated with nano hydroxyapatite by dip coating. St
... Show MoreWe have studied the effect of gamma irradiation on the optical transmission, absorbance, absorption coefficient, and Urbach energy for (PMMA- doped red methyl) film deposited by using solvent casting method .The optical transmission (T %) in the wavelength range (1901100 ) nm of films was measured , it was seen that all the parameters were affected by gamma irradiation.
The fouling depositions of crude oil stream were studied theoretically in a shell and tube heat exchanger to investigate the effect of depositions on the heat transfer process. The employed heat exchanger was with steam flowing in the inner tubes and crude oil in the shell at different velocities and bulk temperatures. It is assumed that fouling occurs only on the heated stream side (crude oil). The analysis was carried out for turbulent flow heat transfer conditions with wide range of Reynolds number, bulk temperature and time. Many previously proposed models for fouling resistance were employed to estimate a new model for fouling rate. It is found that the fouling rate and consequently the heat transfer coefficient were affected by Rey
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