Resilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixing as filler dispersion method and the surface topography, respectively. Both SEM and AFM images showed that the zirconia nanopowder were distributed fairly well within the polymer. Statistically, highly significant increase in tear strength, tensile strength and hardness with non-significant decrease in elongation at break and non-significant increase in surface roughness were seen with 1% and 2% groups. Whereas with 3% group, there was significant improvement in tear strength, tensile strength and hardness but there was significant undesirable decrease in elongation and increase in roughness. Cytotoxicity test revealed that the addition of zirconia nanopowder was nontoxic to Rat Embryonic Fibroblast (REF) cells and there was non-significant change in the cell viability of all study groups after 24- and 72-hours incubation periods. In conclusion, the addition of 2% by weight nano zirconia to VST-50 maxillofacial silicone could be beneficial in enhancing its performance.
In this research has been the manufacture and study the properties of the solar cell type retail hybrid manner thermal evaporation emptiness were studying the properties of the cell at room temperature showed measurements stream circuit behavior linear cell manufacturers reached were calculated efficiency tool cell manufacturers, as well as the expense of workers filling the cell
The reaction of(2-oxo-2H-chromen-3-Carbonyl chloride)(k1) with hydrazine in boiling ethanol gives the hydrazide(K2).When compound (k2) reacts with various aromatic aldehydes ,the corres ponding Schiff bases(k3–k4) achieve new series of thiazotidines (k5–k6) and azetidinones (k7–k8) obtained from the reactions of appropriate Schiff bases with mercapto acetic acid and chloro acetyl chloride respectively. All the compounds are characterized by FT-IR,1H-NMR and GC-Ms.
Individual mobility is an outcome of the rapid changes in life; it is revealed in particular literary works within the end of the 19th century. Mobility is clearer in modern time as the individual has become physically freer in his movement. But the individual’s freedom is often conditioned by restrictions. Usually, change stimulates individuals to obtain new structure of feeling; the individual mocks or rages against institutions, or he would comply, suffering rapid personal deterioration as he faces effective stability or institutions. There is a continuous sense of “deadlock.” Sylvia Plath’s novel reflects the depression of an intellectual young woman who fails to find her right path muddled by an inconsistent, confusing
... Show MoreF index is a connected graph, sum of the cubes of the vertex degrees. The forgotten topological index has been designed to be employed in the examination of drug molecular structures, which is extremely useful for pharmaceutical and medical experts in understanding the biological activities. Among all the topological indices, the forgotten index is based on degree connectivity on bonds. This paper characterized the forgotten index of union of graphs, join graphs, limits on trees and its complements, and accuracy is measured. Co-index values are analyzed for the various molecular structure of chemical compounds
This study is conducted to carry out a straightforward way appropriate for quality monitoring and stability of arc stud welding process, followed by a number of procedures to control the quality of welded samples, namely torque destructive testing and visual inspection context. Those procedures were being performed to support the monitoring system and verify its validity. Thus, continuous on-line monitoring guarantees earlier discovering stud welding defects and avoiding weld repeatability. On-line welding electronic monitoring system is for non destructive determining if a just completed weld is satisfactory or unsatisfactory, depending on welding current peak value detected by the system. Also, it has been observed significant ha
... Show MoreAbsorption and lifetime measurements were made for C6H6. and C6D6 molecules in pure solid phase and in solid matrices of Ar, N2, CO, and CO2. All measurement are made at low temperatures ranging between 12-50 K. A modified least square fitting deconvolution was utilized to measure the fluorescence lifetime with an error less than 1%. The results show that the use of matrix isolation technique offer a unique environment that minimize the perturbation of the molecular or atomic system and hence facilitate spectral analysis.
Many of the signs that the global energy system indicate the start of a period of transition from total dependence on fossil energy sources, especially oil, into a new era in which alternative energy sources play an important role in meeting the growing needs of energy demand, so sought many of the developed countries through research the studies carried out to try to bring renewable energy sources and non-renewable (shale oil, oil sands, solar energy, wind energy .... etc) replace traditional fossil energy sources (oil, gas, coal) and despite the recent availability dramatically and spread throughout the the world, but they are going to dry up in the foreseeable future. So many countries, especially the developed sought to find
... Show MoreThe genera and species of Liliaceae show a considerable structural diversity of leaves and especially stems. This paper presents a morphological and anatomical study of the leaves and stems of Asphodelus microcarpus. The results showed that the investigated species had typical morphological characters. and also that it could be distinguished from another plant not only by its morphological but anatomical characters as well.