• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.156-169
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• 1997

This study was designed to evaluate the influences of evaporation of liquid of dental cements by drying during long term using. Zinc phosphate cement, polycarboxylate cement, and glass ionomer cement were used, and evaluated the properties as follows; consistency, setting time, film thickness, solubility, and compressive strength according to the ADA specification. The specimens of control group were made by mixing the newly opened liquid using the powder-liquid ratio recommended by the manufacturer, and the specimens of ES groups were made by mixing the 10% evaporated liquid by drying with the powder-liquid ratio recommeded by the manufacturer, and the specimens of EM group were made by mixing the 10% evaporated liquid with the powder-liquid ratio modified for standard consistency. The following conclusions were drawn ; 1. The viscosity of mixture of all kinds of cements were increased by the evaporation of liquid, especially the viscosity of glass ionomer cement were influenced significantly. 2. The amount of liquid should be increased to get a standard consistency at the using of evaporated liquid of cement, the most significant increase of liquid amount was required on Ketac-Cem. 3. The setting times were increased at both cases of mixing of evaporated liquid with powder - liquid ratio recommended by manufacturer or modifided through consistency test. 4. At an experimental group of mixing of the evaporated liquid with powder-liquid ratio recommended by manufacturer, solubility was decreased and film thickness was increased. 5. By the result of evaporation of cement liquid, the compressive strength of polycarboxylate cement was increased slightly and it of glass ionomer cement was increased, however, by the increase of amount of liquid to be possible to manipulate the compressive strength were decreased.

• 대한치과보철학회지
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• 제45권6호
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• pp.735-742
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• 2007

Statement of problem. Although a number of previous investigations have been carried out on the polymerization shrinkage-strain kinetics of provisional crown and fixed partial denture (FPD) materials, the effect of the changes of liquid monomer to powder ratio on its polymerization shrinkage-strain kinetics has not been reported. Purpose. The purpose of this study was to investigate the influence of liquid monomer to powder ratio of polymer-based provisional crown and FPD materials on the polymerization shrinkage-strain kinetics. Material and methods. Chemically activated acrylic provisional materials (Alike, Jet, Snap) were investigated. Each material was mixed with different liquid monomer to powder ratios by volume (1.0:3.0, 1.0:2.5, 1.0:2.0, 1.0:1.5, 1.0:1.0). Time dependent polymerization shrinkage- strain kinetics of all materials was measured by the bonded-disk method as a function of time at $23^{\circ}C$. Five recordings were taken for each ratio. The results were statistically analyzed using one-way ANOVA and the multiple comparison Scheffe test at the significance level of 0.05. Trends were also examined by linear regression. Results. At 5 minutes after mixing, the polymerization shrinkage-strains of all materials ranged from only 0.01% to 0.49%. At 10 minutes, the shrinkage-strain of Alike was the highest, 3.45% (liquid monomer to powder ratio=1.0:3.0). Jet and Snap were 2.69% (1.0:2.0) and 1.58% (1.0:3.0), respectively (P>0.05). Most shrinkage (94.3%-96.5%) occurred at 30 minutes after mixing for liquid monomer to powder ratio, ranging from 1.0:3.0 to 1.0:1.0. The highest polymerization shrinkage-strain values were observed for the liquid monomer to powder ratio of 1.0:3.0. At 120 minutes after mixing, the shrinkage-strain values were 4.67%, 4.18%, and 3.07% for Jet, Alike, and Snap, respectively. As the liquid monomer to powder ratio increased, the shrinkage-strain values tend to be decreased linearly (r=-0.769 for Alike, -0.717 for Jet, -0.435 for Snap, $r^2=0.592$ for Alike, 0.515 for Jet, 0.189 for Snap; P<0.05). Conclusion. The increase of the liquid monomer to powder ratio from 1.0:3.0 to 1.0:1.0 had a significant effect on the shrinkage-strain kinetics of polymer-based crown and FPD materials investigated. This increased the working time and decreased the shrinkage-strain during polymerization.

• Journal of Welding and Joining
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• 제23권6호
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• pp.99-105
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• 2005

The mixing ratio effect of the GTD-111(base metal) powder and the GNI-3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder on TLP(Transient Liquid Phase) bonding phenomena and mechanism was investigated. At the mixing ratio of the base metal powder under $50wt\%$, the base metal powders fully melted at the initial time and a large amount of the base metal near the bonded interlayer was dissolved by liquid inter metal. Liquid insert metal was eliminated by isothermal solidification which was controlled by the diffusion of B into the base metal. The solid phases in the bonded interlayer grew epitaxially from the base metal near the bonded interlayer inward the insert metal during the isothermal solidification. The number of grain boundaries farmed at the bonded interlayer corresponded with those of base metal. At the mixing ratio above $60wt\%$, the base metal powder melted only at the surface of the powder and the amount of the base metal dissolution was also less at the initial time. Nuclear of solids firmed not only from the base metal near the bonded interlayer but also from the remained base metal powder in the bonded interlayer. Finally, the polycrystal in the bonded interlayer was formed when the isothermal solidification finished. When the isothermal solidification was finished, the contents of the elements in the boned interlayer were approximately equal to those of the base metal. Cr-W borides and Cr-W-Ta-Ti borides formed in the base metal near the bonded interlayer. And these borides decreased with the increasing of holding time.

• Journal of Welding and Joining
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• 제25권3호
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• pp.64-71
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• 2007

The dissolution phenomenon of the solid phase powder and base metal by liquid phase insert metal during Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111(base metal) powder and the GNi3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder was investigated. In case of the mixed powder contains modified GTD111 powder 50wt%, all of the powder was melted by liquid phase at 1423K. At the temperature between solidus and liquidus of GNi3, liquid phase penetrated into the boundary of the modified GTD111 powder and solid particle separated from powder was melted easily because area of reaction was increased. With increasing mixing ratio of the modified GTD111, it needed the higher temperature to melt all of the modified GTD111 powder. During Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111 50wt% and GNi3 50wt% as insert metal, width of the bonded interlayer was increased with increasing bonding temperature by reaction of the base metal and liquid phase in insert metal. Dissolution of the base metal and modified powder by liquid phase progressed all together and after all of the powder was melted nearly, the dissolution of the base metal occurred quickly.

• 자원환경지질
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• 제33권6호
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• pp.519-524
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• 2000

This study has been performed to evaluate the possibility of utilizing stone powder sludges from stone quarry and manufacturing plant as adsorbents for heavy metals in industrial wastewater. The stone powder sludges from stone quarry (IS-01) have the most effective adsorption capacity (above 95％ of initial concentrations) under the given experimental conditions of reaction times (Pb : 15 min, Cu : 2 hr, Zn : 48 hr), initial acidity of solution (pH>3) and dosage (sludge/liquid ratio : 0.02). The stone powder sludges from manufacturing plant (CW-01) show relatively high adsorption capacity (about 95％ of initial concentrations) only for Pb with a reaction times of 12 hours, initial acidity of solution (pH>3) and dosage (sludge/liquid ratio : 0.02). The stone powder sludges (IS-01) from stone quarry having relatively excellent adsorption capacity under the given experimental conditions show their potential utilization as heavy metal adsorbents.

• The Korean Journal of Ceramics
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• 제3권4호
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• pp.235-238
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• 1997

Basic properties of new cement pastes based on the system $CaO-Al_2O_3-P_O_5-H_2O$were studied Phosphoric acid solutions and calcium dialuminate clinkers synthesized by the hydration-burning method were used for liquid and powder components of the paste, respectively Variation in the compositions of the paste was achieved by changing the liquid/powder ratio and the concentration of phosphoric acid solution. The hardening rate of the paste was so largely affected by the amount of phosphoric acid that hardening was inhibited with the low-concentrated solution but was explosively accelerated with the high-concentrated solution. The phosphoric acid solutions of concentration of 45~50% and the liquid/powder ratio of 0.5~1.5 were favoured for the high early-strength cement paste with the reasonable hardening rate and high strength. The binding phase of hardened paste was the dense amorphous gel of the system $CaO-Al_2O_3-P_O_5-H_2O$. in which the unreacted calcium dialuminate grains were embeded.

• 대한치과보철학회지
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• 제38권2호
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• pp.214-225
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• 2000

The purpose of this study was to investigate the effects of investing conditions on the marginal discrepancy of conical telescope outer crown with Co-Cr-Ti alloy(Dentitan) and to compare the marginal discrepancy and the retention force of outer crowns using different pattern materials(plastic foil, casting wax, pattern resin). To evaluate the effects of investing conditions on the marginal discrepancy, patterns with plastic foil were invested under three different liquid/powder ratio conditions using phosphate bonded investment(Univest-nonprecious): standard, 10% decreased and 10% increased. At each liquid/powder ratio condition, metal ring was lined with single or double layers of ceramic ring liner. The marginal discrepancy of outer crown at different investing conditions was measured by ${\times}100$ compact measuring microscope(STM5, Olympus, Japan). For measurement of the marginal discrepancy and the retention force of outer crown using different pattern materials, the investing condition of 10% decreased liquid/powder ratio and double layers of ring liner was selected because this investing condition resulted in the best fit of outer crown. Marginal discrepancy was measured in the same way above and retention force on universal testing machine. Under the conditions of this study, the following conclusions were drawn: 1. The thickness of ring liner had more influence on the marginal discrepancy of outer crown than the liquid/powder ratio, and the acceptable marginal fitness could not be expected at the investing condition directed by investment manufacturer 2. There were no differences in the marginal discrepancy of outer crown among three different pattern materials(P>0.05). 3. Casting wax showed the greatest retention force(1640g) of outer crown, followed by pattern resin(1110g), plastic foil(820g). However, there was no significant difference between plastic foil and pattern resin(P>0.05). 4. Plastic foil showed the least variation in marginal discrepancy and retention force.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.220-225
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• 2003

원자력발전소에서 발생하는 방사성 폐액은 일반적으로 액체폐기물처리계통 폐액증발기 및 농축 폐액건조설비에서 증발 및 건조 공정을 통해 수분을 함유하지 않은 분말형태로 변한다. 이 분말형태의 폐기물은, 취급 시와 처분 후 안전성을 확보할 수 있도록, 파라핀과 균일하게 혼합되어 고화된 후 철제드럼에 포장된다. 농축폐액건조설비를 이용하여 농축폐액을 건조시킨 후 분말 형태의 폐기물을 파라핀과 혼합하는 공정을 수행할 때, 방사성 폐액 중 붕소와 나트륨의 몰비가 0.2를 초과하는 경우, 분말형태의 폐기물이 파라핀과 균일하게 혼합되지 않고 층을 이루어 분리되어 드럼에 안정고화가 잘 안되는 경우가 발생하였고 또한 일부는 드럼화 전에 설비 내에 고착되는 현상이 발생하는 것을 경험하였다.

• 한국조리학회지
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• 제24권3호
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• pp.196-203
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• 2018

This study was examined the quality characteristics of dough liquid according to the additional ratio of Doraji in seaweed snack manufacturing. Firstly, the results of Doraji type (dry & powder) were as follows: Carbohydrates 77.57~79.29, crude protein 9.10-9.25, crude fat 0.96~1.33 and calories 355~366 kcal, pH 5.42~5.45, sugar $3.53{\sim}3.96^{\circ}brix$, color 33.82~44.25 (L), 2.27~3.52 (B) and total free amino acids 2,200~2,699 mg/100 g. Total polyphenol contents had dry extracts 1,931.18 mg% and powder extract 1,382.43 mg%, DPPH and ABTs radical scavenging activities tended to increase with higher treatment concentration. Next, the results showed that dough liquid for seaweed snack manufacture which was added Doraji were as follows: Color became deep poppy red with increased addition of Doraji. The texture of adhesiveness, cohesiveness, chewiness, and brittleness tended to decrease with addition of Doraji. The springness showed the opposite tendency. Accordingly, these results suggest that 20% of dry Doraji extract is a proper proportion so that it can be added to the rice dough liquid to produce form Doraji (dry and powder) containing seaweed snacks.

• 한국분말재료학회지
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• 제27권6호
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• pp.468-476
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• 2020

The bone cement used for vertebroplasty must be sufficiently injectable. The introduction of granules reduces the amount of liquid required for liquefaction, implying that higher fluidity is achieved with the same amount of liquid. By employing β-tricalcium phosphate granules with an average diameter of 50 ㎛, changes in injectability are observed based on the paste preparation route and granular fraction. To obtain acceptable injectability, phase separation must be suppressed during injection, and sufficient capillary pressure to combine powder and liquid must work evenly throughout the paste. To achieve this, the granules should be evenly distributed. Reduced injection rates are observed for dry mixing and excessive granular content, owing to phase separation. All these correspond to conditions under which the clustered granules weakened the capillary pressure. The injected ratio of the paste formed by wet mixing displayed an inverted U-type shift with the granular fraction. The mixture of granules and powder resulted in an increase in the solid volume fraction, and a decrease in the liquid limit. This resulted in the enhancement of the liquidity, owing to the added liquid. It is inferred that the addition of granules improves the injectability, provided that the capillary pressure in the paste is maintained.