• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.2
• /
• pp.182-190
• /
• 2009

Statement of problem: Microleakage at the occlusal and gingival margin of Class V cavities restored with composite resin has traditionally been considered an obstacle to successful restoration. Purpose: The aim of this study was to assess the effectiveness of three different surface sealants(Fortify, Permaseal and Biscover LV) on the marginal sealing of Class V light-activated composite resin restorations(Z250). Material and methods: Forty noncarious human premolars and molars extracted within a three-month period were selected. Class V cavities with the occlusal margin in enamel and gingival margin in cementum were prepared in both buccal and lingual surfaces. The teeth, randomly assigned in four groups with twenty cavities in each group, were restored with composite resin after applying an adhesive system(Clearfil SE bond). After the finishing and polishing procedures, the restorations were covered with a specific surface sealants, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled, and immersed in a 2% methylene blue solution for twenty four hours and sectioned longitudinally. The marginal microleakage was evaluated at the occlusal and gingival interfaces using a microscope and compared among the four groups using ANOVA test and Wilcoxon Rank-Sum test($\alpha$=0.05). Results: Statistical analysis showed that there was significantly less leakage when the surface sealants were used than there was in control group(P<.05). There were no significant differences of microleakage at occlusal and gingival margins among groups. There were no significant differences between microleakage of occlusal and gingival margins in each group. Fortify was not statistically different from control group at the gingival margin(P>.05). Conclusion: Application of surface sealants was an effective method of surface coating in reducing microleakage at occlusal and gingival margins of Class V composite resin restorations. However, it is certain that some microleakage still occurred despite the application of surface sealants, especially gingival margins.

• Food Science of Animal Resources
• /
• v.31 no.2
• /
• pp.296-303
• /
• 2011

This study was conducted to determine the effects of stevia (Stevia rebaudiana Bertoni) and charcoal supplementation on meat quality traits in finishing pigs. A total of 420 pigs (LYD) were randomly allocated into seven treatments with three replications. The dietary treatments were T1 (control, basal diet), T2 (basal diet+0.3% stevia), T3 (basal diet+0.6% stevia), T4 (basal diet+0.3% charcoal), T5 (basal diet+0.6% charcoal), T6 (basal diet+0.3% stevia+0.3% charcoal), and T7 (basal diet+0.6% stevia+0.6% charcoal). Pigs were slaughtered conventionally on each marketing day and chilled overnigth. At 24 h postmortem, the Longissimus muscle from left side between the 6th and 14th rib was removed for the meat quality traits. The T6 group showed a higher pH, water holding capacity (p<0.05), and lower drip loss (p<0.05) than those in the T1 group. The T6 group showed lower (p<0.05) $L^*$ (lightness) and $b^*$ (yellowness) values and higher $a^*$ (redness) color value than those in the T1 group, resulting in a redder surface meat color. In the subjective evaluation, marbling and color scores improved in the T6 group compared to those in the other treatments. In the panel test, the T6 group tended to have higher tenderness and juiciness scores than those in the T1 group. In the storage characteristics, all treatments showed similar 2-thiobarbituric acid and volatile basic nitrogen values as well as total microbial counts during 7 d of cold storage. As a result, dietary supplementation with 0.3% stevia and 0.3% charcoal showed the highest meat quality traits and storage characteristics in finishing pigs.

• The korean journal of orthodontics
• /
• v.27 no.5 s.64
• /
• pp.791-800
• /
• 1997

Sixty premolars extracted for orthodontic treatment were divided into four groups, and the residual resin was removed with four different rotary finishing instruments at a fixed speed of $18,500{\pm}300 rpm$ on the low speed handpiece. The instruments were G1; No.169L carbide fissure bur, G2: No.2 round bur, G3; No.4 round bur, G4: No.8 round bur. Then, the enamel received a S-second polishing with a rubber cup and a pumice. To find the extent of loss on the enamel at this point, prophylaxis was done with the rubber cup and pumice prior to bonding of the bracket(P1) and removal of residual resin by means of appropriate procedure applicable to each respective group(P2) followed. The final polishing was done with the rubber cup and pumice(P3), and the enamel surface roughness was measured each by the surface measuring instrument. The whole process was observed under a scanning electron microscope to gain the following results: At P2, the enamel surface roughness in G1 showed most smoothly with $2.60{\pm}0.55{\mu}m;\;in\;G2,\;3.24{\pm}0.80{\mu}m;\;in\;G3,\;3.44{\pm}0.94{\mu}m;\;in\;G4,\;3.89{\pm}0.54{\mu}m$, the roughest. G2 and G3 showed no statistical significance(P>0.05). At P3, the enamel surface roughness in G1 showed most smoothly with $2.29{\pm}0.47{\mu}m;\;in\;G2,\;2.44{\pm}0.56{\mu}m;\;in\;G3,\;2.44{\pm}0.56{\mu}m;\;in\;G4,\;2.92{\pm}0.43{\mu}m$, the roughest. G1 vs G2, G3, and G2 vs G3 had no statistical significances(p>0.05). In all groups, P2 and P3 showed rougher in surface roughness than P1, and P2 rougher than P3(p<0.01). In a case of 5-second prophylaxis with the rubber cup and the pumice on a virgin, normal enamel, fine scratches were found under the scanning electron microscope. In all four groups, unremovable gouges remained even after polishing with the ubber and pumice; residual resin was not observed with naked eye when finished with the rubber and pumice, but the resin debris was observed under the scanning electron microscope.

• Textile Coloration and Finishing
• /
• v.28 no.2
• /
• pp.70-76
• /
• 2016

Silver nanoparticles(AgNPs) were attached to wool fibers using glycidyltrimethylammonium chloride(GTAC), which is a type of quaternary ammonium salt. GTAC, which contains an epoxy functional group that, under high temperatures, generates a ring-opening reaction with wool fibers, which contain the amine group. Then, the AgNPs are attached to the surface of the GTAC-treated wool fibers by treatment with a silver colloidal solution. The process involves the following procedures: (1) The wool fibers are immersed in the GTAC solution, followed by pre-drying at $80^{\circ}C$ and curing at $180^{\circ}C$ to induce an alteration in the chemical structure; and (2) The wool fibers treated with GTAC are immersed in the silver colloid at $40^{\circ}C$ for 120 min to chemically induce a strong attachment of the AgNPs to the wool fibers. Scanning electron microscopy was used to analyze the influence of the concentrations of GTAC and the silver colloid, as well as the influence of the applied temperature of the silver colloid on the wool fibers, and the influence of the morphological changes in the wool fiber surfaces. As a result, the enhanced concentrations of GTAC and the silver colloid together with an elevated applied temperature of silver colloid have a tendency to increase in Ag atomic%.

• Advances in concrete construction
• /
• v.9 no.3
• /
• pp.235-248
• /
• 2020

Progressive collapse in a structure occurs when load bearing members are failed and the adjoining structural elements cannot resist the redistributed forces and fails subsequently, that leads to complete collapse of structure. Recently, construction using precast concrete technology is adopted increasingly because it offers many advantages like faster construction, less requirement of skilled labours at site, reduced formwork and scaffolding, massive production with reduced amount of construction waste, better quality and better surface finishing as compared to conventional reinforced concrete construction. Connections are the critical elements for any precast structure, because in past, major collapse of precast structure took place because of connection failure. In this study, behavior of four different precast wet connections with U shaped reinforcement bars provided at different locations is evaluated. Reduced 1/3^rd scale precast beam column assemblies having two span beam and three columns with removed middle column are constructed and examined by performing experiments. The response of precast connections is compared with monolithic connection, under column removal scenario. The connection region of test specimens are filled by cast-in-place micro concrete with and without polypropylene fibers. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection at the location of removed middle column, crack formation and failure propagation. Further, Finite element (FE) analysis is carried out for validation of experimental studies and understanding the performance of structural components. Monolithic and precast beam column assemblies are modeled using non-linear Finite Element (FE) analysis based software ABAQUS. Actual experimental conditions are simulated using appropriate boundary and loading conditions. Finite Element simulation results in terms of load versus deflection are compared with that of experimental study. The nonlinear FE analysis results shows good agreement with experimental results.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.1
• /
• pp.50-55
• /
• 2017

Foamed aluminum is an eco-friendly material that is reusable and safe against fire. These superior characteristics have many advantages in the field of building and construction and in cruise ships as sound absorbers. So far, the research on foamed aluminum has been focused on the sound absorption performance using the foaming ratio. Foamed aluminum, when compared with the existing sound absorbers such as glass wool or rock wool, has a better structural performance, and it can be installed on walls in many different ways. This study conducted experiments on the sound absorption characteristics considering the various applications of foamed aluminum. The effects of painting surfaces with the finishing material were compared to that of the normal surface, and the effects of vertical installation and hanging from the ceiling was compared with the effects of installing on the floor.

• Textile Coloration and Finishing
• /
• v.18 no.3 s.88
• /
• pp.49-58
• /
• 2006

The purpose of this study was to examine the effect of covering yarn's twist on mechanical properties of knitted fabrics of composite yarns with single covering process. Four yarns that were used in this study: two different composite yarns made from the four kinds of cotton and functional polyester-(Poly-A) with the ratio of 52:48, and the rest two yarns are the original cotton 100% yarn and the poly-A 100% yarn. The two kinds of composite yarns, CP1 and CP2, were processed on the single covering process. CP1 was applied on the single covering process with S-800 tpm, where Poly-A was used as covering yarn and cotton was used as core yarn. CP2 was applied on the same process as CP1 except that Poly-A had been applied on the two-for-one twisting process with S-400 tpm on the previous step. Sixteen mechanical properties of all the four knifed fabrics knitted under the same knitting conditions were measured by KES-FB system with the outer knit condition. And 3D CAD dressmaking simulations, which were driven by some of the mechanical properties, were presented. The results were as follows: CP2 had high RT values with twisting of covering yarn. CP2 also had high B, 2HB values because of higher linear density. SMD was affected rather by twisting of covering yarn than by fine hair of the cotton surface. Twisting of covering yarn made it decreasing T value and increasing W value. Dressmaking 3D CAD simulations showed that there are buckling effects on CP2 because of high bending rigidity and shear rigidity.

• Textile Coloration and Finishing
• /
• v.20 no.6
• /
• pp.42-50
• /
• 2008

The objective of this study is to investigate the efficacy of pomegranate hull colorant as a natural hair coloring dye. The extract of pomegranate hull was concentrated and freeze-dried to get colorant powder. Effect of dyeing condition and mordanting on the dye uptake of hair by using Al, Fe, Cu, Cr, Sn compounds, color change and colorfastness were explored. In addition, tensile strength was measured and the surface of the hair was observed. Dye uptake of hair measured by K/S value (400 nm) indicated that ionic bonding seems to be involved in the sorption of pomegranate colorant to hair. Maximum sorption was obtained at pH 3.5 and the concentration of 50% (on the weight of hair, o.w.h.). Acidic dyeing condition (pH $3.5{\sim}5.0$) showed yellow color however alkaline dyeing condition (pH $7{\sim}11$) gave reddish yellow color. Pomegranate hull colorant produced greyish brown color on hair and the hair mordanted with Fe showed dark brown color. Mordants except Fe did not increase dye uptake significantly. Mordants except Cu increased light fastness and mordants except Cr increased washing fastness level slightly. According to SEM observation and the tensile strength retention measurement, the mordant dyed hair gave more damage to hair by ultraviolet light and washing than the hair dyed without mordanting. Experimental results of K/S value and colorfastness(light and washing) supported that pomegranate hull colorant without mordanting can be used as a semi-permanent natural hair coloring dye.

• Textile Coloration and Finishing
• /
• v.20 no.2
• /
• pp.19-28
• /
• 2008

The objective of this study was to apply the statistical technique known as design of experiments to optimize the % exhaustion variables for phthalocyanine dyeing of nylon fiber. In this study, a three-factor Central Composite Rotatable Design (CCRD) was used to establish the optimum conditions for the phthalocyanine reactive dyeing of nylon fiber. Temperature, pH and liquor ratio were considered as the variable of interest. Acidic solution with higher temperature and lower liquor ratio were found to be suitable conditions for higher % exhaustion. These three variables were used as independent variables, whose effects on % exhaustion were evaluated. Significant polynomial regression models describing the changes on % exhaustion and % fixation with respect to independent variables were established with coefficient of determination, R2, greater than 0.90. Close agreement between experimental and predicted yields was obtained. Optimum conditions were obtained using surface plots and Monte Carlo simulation techniques where maximum dyeing efficiency is achieved. The significant level of both the main effects and interaction was observed by analysis of variance (ANOVA) approach. Based on the statistical analysis, the results have provided much valuable information on the relationship between response variables and independent variables. This study demonstrates that the CCRD could be efficiently applied for the empirical modeling of % exhaustion and % fixation in dyeing. It also shows that it is an economical way of obtaining the maximum amount of information in a short period of time with least number of experiments.

• Textile Coloration and Finishing
• /
• v.29 no.4
• /
• pp.195-201
• /
• 2017

To study the effect of oxyfluorination on water dispersion of phthalocyanine blue(C.I. pigment blue 15:3), the pigment was oxyfluorinated using various oxygen to fluorine ratio of the reactant gas. After the oxyfluorination of the phthalocyanine blue pigment, no significant change in FT-IR spectra was observed, whereas XPS spectra showed the introduction of oxygen and fluorine containing functional groups. This suggests that the oxyfluorination of the pigment only occurred on the surface of the pigment particle and resulted in no significant change in UV-Vis spectra of the pigment. However, the oxyflurinated pigments showed improved water dispersion, compared to the non-treated pigment. Especially, when the oxygen to fluorine ratio was 47:3, the water dispersion of the oxyfluorinated pigments significantly increased, compared to the non-treated pigments. This suggests that the oxyfluorination of the phthalocyanine blue pigment has a potential to be used as a water dispersion improving method.