Denture bases are fabricated routinely using Poly(methyl methacrylate) (PMMA) acrylic resin. Yet, it is commonly known for its major drawbacks such as insufficient strength and ductility. The purpose of this study was to improve the performance of PMMA acrylic resin as a denture base material by reinforcement with surface treated lithium disilicate glass ceramic powder. The ceramic powder was prepared by grinding and sieving IPS e.max CAD MT blocks. Then, the powder was surface treated with an organosilane coupling agent (TMSPM) and added to PMMA in amount of 1%, 3%, 5% and 7% by weight. Characterizations of the powder was done by particle size analysis, XRD and FTIR. Transverse strength, Impact strength, Shore D hardness and surface roughness were tested for the prepared composites and neat PMMA. Particle size analysis showed that the average particle diameter was 1.46 µm. XRD confirmed the microstructure of IPS e.max CAD MT. FTIR showed the presence of TMSPM functional groups in the powder after treatment and there was a chemical interaction between the treated powder and the PMMA after the addition. One-way ANOVA and Tukey’s HSD test showed that there was a highly significant increase (P < 0.01) in transverse strength, impact strength and hardness with non-significant increase in roughness for 1% group. The mean values of 1% group were 67.3 MPa for transverse strength, 5.21 kJ/m2 for impact strength, 89.8 for Shore D hardness and 1.22 µm for surface roughness. While for control group, mean values were 59.3 MPa for transverse strength, 3.74 kJ/m2 for impact strength, 87.1 for Shore D hardness and 1.1 µm for surface roughness. However, with higher amounts of powder, there was a highly significant decrease in transverse strength and increase in roughness which was considered undesirable. In conclusion, reinforcing PMMA denture base material with 1% lithium disilicate glass ceramic powder may have the potential for enhancing the clinical performance of this material.
Thin films whose compositions can be expressed by (GeS2)100-xGax (x=0, 6,12,18) formula were obtained by thermal evaporation technique of bulk material at a base pressure of ~10-5 torr. Optical transmission spectra of the films were taken in the range of 300-1100 nm then the optical band gap, tail width of localized states, refractive index, extinction coefficient were calculated. The optical constants were found to increase at low concentration of Ga (0 to12%) while they decreases with further addition of Ga. The optical band gap was found to change in opposite manner to that of optical constants. The variation in the optical parameters are explained in terms of average bond energy
... Show MoreThe effect of Al dust particles on glow discharge regions, discharge
voltage, discharge current, plasma potential, floating potential,
electron density and electron temperature in planar magnetron
sputtering device has been studied experimentally. Four cylindrical
Langmuir probes were employed to measure plasma parameters at
different point on the radial axis of plasma column. The results
shows the present of Al dust causes to increase the discharge voltage
and reduce the discharge current. There are two electron groups in
the present and absent of Al dust particles. The radial profiles of
plasma parameters in the present of dust are non- uniform. The
floating potential of probe becomes more negatively while
Sulphated zirconia (SZ) is one of the most important solid acid catalysts was synthesize at different operating conditions, different calcination temperature and sulfonating time has been used. The prepared catalyst was distinguished by X-ray Diffraction (XRD), particle size and morphology of catalyst were checked by atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively, in addition to analysis by (DTA) Differential thermally and Energy Dispersive X-Ray (EDX). Finally, the N2 adsorption-desorption was used to measure the surface area (BET) and pore volume. High degree of tetragonal crystallinity was obtained 90 %, and surface area of 169 m2/g and pore volume of 0.39 cm3g-1 at 600°C calcination temperature for 3
... Show MoreThin films of In2O3-CdO at various CdO contents (0.01, 0.02, 0.03, 0.04 and 0.05) were deposited on transparent substrate which is glass using chemical spray pyrolysis deposition method at substrate temperature 150oC. The structural properties was studied to characterize the prepared materials by XRD analysis. Surface morphology has been illustrated using scanning electron microscopy which proved the nanosize of prepared materials. This materials have been used as gas sensor for toxic gas which is hydrogen sulfide H2S. The sensitivity and response speed have been investigated with addition of CdO nanoparticles. © 2021, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
Suggested in this study the introduction of monomers have the ability to interact with polyester Rzn way confused or Alchapak Vodev polycarbonate first Almiaal acrylate ????? grains and offered models for high temperature and for a period of time of 40 days and absorbance and penetration and after color changes resulting from the storage heat higher using shades where models were extractedthermal storage and take measurements and then returned periodically results were consistent with theoretical expectations and mixing
This paper provides the result of an investigation to use of crushed clay brick as
aggregates in producing concrete. Eight different crushed clay brick aggregate concretes were
used in this investigation. Compressive strength, splitting tensile strength and pulse velocity of
crushed clay brick aggregates concrete were determined and compare to natural aggregate
concrete. The compressive strength of crushed clay brick aggregates concretes were always
lower than the compressive strength of natural aggregates concrete regardless the age of
concrete, but the crushed clay brick aggregates concrete showed better performance as the age of
concrete increases and average reduction in compressive strength were 33.5% at the age
Bentonite is widely used in industrial applications. The present study reports the effect of adding different weights of ZnO to the Iraqi bentonite, on surface area, pore volume and real density. These surface properties were evaluated for pure and modified bentonite. The modification was made by adding different ZnO weights such as; ( 0.5%, 1%, 5%, 10% ). The effect of heat exposing for all modified clay samples at 500 ?C have been also evaluated. The results show that the addition of 0.5% ZnO leads to increase the surface area percentage about 36%, increase pore volume percentage about 5.48% and increase the real density percentage about 27.116%. When the samples exposed to 500 ?C, their surface area and pore volumes have been decreased a
... Show More57 isolates of Mycobacterium tuberculosis and Mycobacterium bovis were identified; they were isolated from different clinical sources which included sputum, bronchial wash, abscess, pleural fluid, gastric fluid, eye fluid, and CSF, also urine and ear swab. This investigation was carried out on 198 patient attended National Reference Laboratory for T.B during September 2009. Also the study declared that the ratio of separation of this bacterium from male was (67.6%) and it’s higher than the ratio of separation this bacterium from females which was (32.3%). The susceptibility of Mycobacterium tuberculosis to melatonin was evaluated. Many concentrati
... Show MoreIn this paper the definition of fuzzy normed space is recalled and its basic properties. Then the definition of fuzzy compact operator from fuzzy normed space into another fuzzy normed space is introduced after that the proof of an operator is fuzzy compact if and only if the image of any fuzzy bounded sequence contains a convergent subsequence is given. At this point the basic properties of the vector space FC(V,U)of all fuzzy compact linear operators are investigated such as when U is complete and the sequence ( ) of fuzzy compact operators converges to an operator T then T must be fuzzy compact. Furthermore we see that when T is a fuzzy compact operator and S is a fuzzy bounded operator then the composition TS and ST are fuzzy compact
... Show MoreThe microstructure and wear properties of 392 Al alloy with different Mg contents were studied using centrifugal casting. All melted alloys were heated to 800 ºC and poured into the preheated centrifugal casting mold (200-250 ºC) at different mould rotational speeds (1500, 1900 and 2300 r.p.m). It is clear from the results obtained that wear rate was dependent on the Mg content, applied load and mould rotational speed. Furthermore, wear test showed that the minimum wear rate was found in the inner layer of produced rings at mould rotational speed of 1900 r.p.m and Mg content of 5%.