Background: The accuracy of fitness of any dental casting is imperative for the success of any prosthodontic treatment. From the time that dental casting was first introduced, efforts have been made to produce more accurate and better fitted castings with minimal marginal discrepancy. The aim of this in vitro study was to evaluate the effects of three different investing and burnout techniques on the vertical marginal discrepancies ofceramometalcopings invested with two types of phosphate- bonded investments. Materials and methods: Sixty wax patterns were fabricated on a standardized prepared brass die representing an upper central incisor by the aid of a custom-made split mold. Three different investing and burnout techniques were applied for an Iraqi investment and a commercial type; Group I:Ring investing with conventional burnout technique (RC);Group II: Ringless investing with conventional burnout technique (RLC);Group III: Ring investing with accelerated burnout technique (RA).Twenty wax patterns of each group were divided into two subgroups according to the type of investment material used (10 for each subgroup) represented as (B) for the BellaStar XL and (W) for the WYMvest investments. Complete castings were finished and seated on the metal die. The accuracy of fit of each coping was determined by measuring the vertical marginal discrepancies between the finish line on the metal die and the margins of each coping at four specific reference points on the labial, mesial, palatal, and distal aspects of the die by the aid of a light microscope supplied with a digital camera.The arithmetic mean of each three records was computed and regarded as the amount of the marginal discrepancy of each coping and was used as a unit for the statistical analysis. Results: Mean marginal accuracy for W(RLC)was found to be the least (13.839+4.5724 um) while the highest mean value related to B(RLC) (29.033+2.102 um). In general, ANOVA test showed significant results among the mean values of the Binvestment subgroups while LSD test showed non-significance between the (RA) and both the (RC) and (RLC) subgroups. On the other hand, significance was present between the (RLC) and (RA)of the Winvestment subgroups while non-significance was located between the (RC) and both the (RLC) and (RA) subgroups. Comparing similar subgroups of the two tested investments, the Student's t-test showed non-significance between the (RC) subgroups while high significance was located between the (RLC) and (RA) subgroups respectively.Concerning the vertical marginal discrepancy of the copings, applying the (RC) technique for both investments caused non-statistical significance between the labial, mesial, palatal, and distal aspects.The (RLC) technique caused high significance between the four aspects, while the (RA) technique caused non-significance between the labial aspect only and the others. Conclusion: The Iraqi investment generally produced less vertical marginal discrepancies (using the three different investing and burn-out techniques) than the commercial investment.In order to achieve a better marginal fit, it seems that ceramometalcopings invested with the commercial investment tested are better be cast using the conventional ring investing and burnout technique.
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Herein, the interfacial polymerization method has been used for the synthesis of PPy/NaVO3 composites with different compositions of NaVO3 (10 %, 20 %, 30 %, 40 % and 50 %) as an efficient electrode material for supercapacitors. The successful formation and composition of the as-prepared composites (PV1-PV5) were confirmed by FTIR, XRD, EDX, and SEM analysis. The electrochemical properties were investigated by cyclic voltammetry (CV), galvanometric charge–discharge measurement (GCD), and electrochemical impedance spectroscopy (EIS) in 0.5 M H2SO4 electrolyte. As compared to other, the PV4 composite exhibit excellent specific capacitance of 391 F g−1 at a current density of 0.75 A/g with good cycling stability of ∼59 % after 1000 cycle
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In this work, mesoporous silica SBA-15 was prepared and functionalized with amine groups (i.e., NH2) to form NH2/SBA-15. The curcumin (CUR) was encapsulated into the surface and pore of NH2/SBA-15 to create CUR@NH2/SBA-15 as an efficient carrier in drug delivery systems (DDSs). The three samples (i.e., SBA-15, NH2/SBA-15, and CUR@NH2/SBA-15) were characterized. The study investigated the effect of the carrier dose, initial CUR concentration, pH, and contact time on the CUR loading efficiency (DLE%) via adsorption. The best DLE% for the SBA-15 and NH2/SBA-15 were found to be 45% and 89.7%, respectively. The Langmuir isotherm had a greater correlation coefficient (R2) of 0.998 for SBA-15. A pseudo-secondorder kinetic model seemed to fit well
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In the present study, magnet silica-coated Ag2WO4/Ag2S nanocomposites (FOSOAWAS) were fabricated via a multistep method to address the drawbacks related to single photocatalysts (pure Ag2WO4 and pure Ag2S) and to clarify the significant influence of semiconductor heterojunction on the enhancement of visible-light-driven organic degradation. Different techniques were performed to investigate the elemental composition, morphology, magnetic and photoelectrochemical properties of the fabricated FOSOAWAS photocatalyst. The FOSOAWAS photocatalyst (1 g/L) exhibited excellent photodegradation efficiency (99.5%) against Congo red dye (CR = 20 ppm) after 140 min of visible-light illumination. This result confirmed the ability of the heterojunction be
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In this paper, isobutane (R-600a) is used as a suitable substitute for (R-134a) when changing the length of capillary tube. And the experimental data on capillary tube are obtained under different conditions such as (subcooling and ambient temperatures) on domestic refrigerator (9ft3 size), this data shows that (R-600a) a suitable substitute for (R134a) .The test presented a model for a steady state, two-phase flow in capillary tube for vapour compression system .The numerical model depends on conservation equations (mass, energy and momentum) as wall as the equation of state for refrigerant. The solution methodology was implemented by using finite difference techniques. The system results indicate that it is possible to change the refri
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This research studies the rheological properties ( plastic viscosity, yield point and apparent viscosity) of Non-Newtonian fluids under the effect of temperature using different chemical additives, such as (xanthan gum (xc-polymer), carboxyl methyl cellulose ( High and low viscosity ) ,polyacrylamide, polyvinyl alcohol, starch, Quebracho and Chrome Lignosulfonate). The samples were prepared by mixing 22.5g of bentonite with 350 ml of water and adding the additives in four different concentrations (3, 6, 9, 13) g by using Hamilton Beach mixer. The rheological properties of prepared samples were measured by using Fan viscometer model 8-speeds. All the samples were subjected to Bingham plastic model. The temperature range studi
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The research problem revolves around the Iraqi public's use of digital television and cinematic websites، and their importance to the academic study and society، as it examines the public's relationship with these websites، usage habits، and the reasons for their interaction with them. And for the prevalence of this phenomenon of use، it was necessary to address the intensity، intentionality، and timing of use to theoretically root the subject of the study، which is one of the modern studies in Iraq and the Arab world. The survey approach، where the research was based on the theory of uses and gratifications that confer positivity and activity on the mass media audience.
The researchers designed
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The aims of this study are to explore the commercial artifacts in the following three kinds of vegetables oils, Nigella Sativa, Trigonella foenum-graecum Linn,and Zingiber officinale. These oils have been very popular medicinal plants which are commonly used in traditional medicine .These commercial oils have been compared with the extracts of these plants.
The physical properties of extracts and commercial oils of these plants have been stuied. We observed that the refractive index of the plants matches and non-significant, while specific gravity of Nigella Sativa has similar specific gravity in both extracts and commercial oil in contrast with Trigonella foenum Linn,and Zingiber officinale and we found significant difference (P<