• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.156-157
• /
• 2017

It is possible in the case of the chemical admixtures for concrete currently being used in actual work sites to omit quality evaluation and replace it with the scores of the admixture manufactures; this can create a problem of decline in reliability in quality on the work site. Therefore this study sought to analyze the degree of influence changes in the solid content rate of lignin- and naphthalene-based water-reducing agents have on the fundamental characteristics of cement mortar. The results showed that in fresh mortar, the flow and amount of air decreases with decrease in the solid content ratio. In hardened mortar, the condensation strength had hardly any effect on the use of lignin-based water-reducing agent, but naphthalene-based water-reducing agent increased with the decrease in the solid content ratio.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.2308-2313
• /
• 2015

In order to produce an optimal performance solid lubricant used in the refractory slates, various compositions of starch, graphite and water were evaluated by testing their viscosity, coefficient of friction and wear performance. At 15% starch content, the degree of viscosity increment rose in proportional to graphite content and the lowest coefficient of friction was observed when the graphite content was at 30 wt%. Our results demonstrate that, as the water content decrease, the ratio of solid content increases, which compromises the surface coating resulting in increase of coefficient of friction. The best wear test result was obtained when the starch content was at 15 wt% with graphite content at either 25 wt% or 30 wt%.

• Journal of the Korean Ceramic Society
• /
• v.33 no.2
• /
• pp.169-176
• /
• 1996

The specimens which were prepared from $\alpha$-Si3N4 with additions of YAG(3Y2O3.5Al2O3)-10 wt% and various AlN contents were sintered in N2 atmosphere at 1$700^{\circ}C$ The effect of $\alpha$,$\beta$-solid solution contents and sintering time on mechanical properties were investigated. As the content of $\beta$-solid solution and sintering time increased the hardness is reduced but the hardness of specimen sintered over 10 hours is constant irrespective of sintering time. While the fracture toughness increased with increasing of $\beta$-solid solution and sintering time. The fracture toughness of specimen with 80% $\beta$-solid solution content increased from 3.89 to 6.66 MPam1/2 with sintering sintering up to 20 hours/ But the amount of increased fracture toughness of specimen with below 20% $\beta$-solid solution content is not significant.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.5
• /
• pp.509-512
• /
• 1991

Rheological property and apparent viscosity(η)of several semi-solid foods were measured with extrusion capillary viscometer. Apparent viscosities of several semi-solid foods ranged from 0.2714 Pa.s to 2.6453 Pa.s Rheological property of spread type semi-solid foods was pseudoplastic (with yield value). Especially, as the moisture content and temperature of Chungkook-jang spread increased, apparent viscosity decreased. On the contrary, as the added soybean oil content of Chungkook-jang spread increased, apparent viscosity also increased.

• Journal of the Korean Ceramic Society
• /
• v.33 no.7
• /
• pp.785-792
• /
• 1996

Formation of Solid Solution and Microstructure in Processureless sintered SiC-AlN compo-site using oxides as a sintering aid at 185$0^{\circ}C$ and 195$0^{\circ}C$ Regardless of SiC/AlN ratio in composition most of sintered specimens showed he complex structure mixed with 2H solid solution and SiC particles. High sintering temperature and large AlN content in starting composition enhanced the formation of 2H solid solution in sintered specimen 2H solid solution showed the spherical shape and core-rim structure. AlN content in the core is higher than that in the rim but SiC content . The size of 2H solid solution on fracture showed the transgranular fracture mode compared with the dispersed SiC particles which showed the intergranular fracture mode.

• Journal of Korea Foundry Society
• /
• v.36 no.6
• /
• pp.215-221
• /
• 2016

In a recent study, the microstructures and mechanical properties of AM80-xSn magnesium alloys with semi solid casting and hot extrusion process were investigated. With increasing Sn content, the amount of ${\beta}$(Mg2Sn) phase increased, while the ${\alpha}-Mg$ dendritic size decreased. The hardness was increased by the Mg2Sn as the Sn content increased. With increasing Sn content, permanent mold cast and semi solid cast AM80 Mg alloy showed less reduction of hardness and also of extruded AM80 Mg alloy after annealing. In the case of the mechanical properties, the extruded semi solid casting AM80 Mg alloy showed higher tensile strength and yield strength with increasing Sn content compared to the extruded permanent mold cast AM80 Mg alloy at room temperature.

• Environmental Engineering Research
• /
• v.23 no.4
• /
• pp.456-461
• /
• 2018

The solid-state anaerobic digestion (SS-AD) has promoted the development and application for biogas production from biomass which operate a high solid content feedstock, as higher than 15% of total solids. However, the digested byproduct of SS-AD can be used as a fertilizer or as solid fuel, but it has serious problems: high moisture content and poor dewaterability. The organic residue from SS-AD has to be improved to address these problems and to make it a useful alternative energy source. Hydrothermal carbonization was investigated for conversion of the organic residue from the SS-AD of livestock waste to solid fuels. The effects of hydrothermal carbonization were evaluated by varying the reaction temperatures within the range of $180-240^{\circ}C$. Hydrothermal carbonization increased the calorific value through the reduction of the hydrogen and oxygen contents of the solid fuel, in addition to its drying performance. Therefore, after the hydrothermal carbonization, the H/C and O/C atomic ratios decreased through the chemical conversion. Thermogravimatric analysis provided the changed combustion characteristics due to the improvement of the fuel properties. As a result, the hydrothermal carbonization process can be said to be an advantageous technology in terms of improving the properties of organic waste as a solid-recovered fuel product.

• Journal of the Korean Ceramic Society
• /
• v.41 no.9
• /
• pp.647-652
• /
• 2004

In aqueous tape casting of alumina slurry systems, the relationships between the suspension compositions and the defects of the dried tapes were discussed. The suspensions compositions were controlled with the ratios of the solids, water and organics binder contents. The effects of the thickness of dried tape and kinds of binder system were also examined. In the defect free region, the apparent viscosity showed nearly same value due to the count balancing effect of solid and organic binder content on the apparent viscosity. When water content was constant, increasing solid led to decrease of organic binder content. The defect free region was narrowed with increasing of casting thickness. When linear type acrylic emulsion binders system (D1000 and D 1035) were used, defect free zone formed the belt type in the triangle of solid, water and organic binder content according to the line of constant water contents. However the defect free region was not found in the cross-link type emulsion binder system (D 1050).

• Journal of Biosystems Engineering
• /
• v.12 no.1
• /
• pp.39-44
• /
• 1987

Measurement methods of moisture content were compared with 7 dried vegetables (red pepper, onion, green onion, garlic, ginger, carrot and radish). The moisture contents of dried vegetables having different moisture contents were determined by atmospheric oven drying, infrared balance, vacuum oven and Karl Fisher methods. Vacuum oven and Karl Fisher methods gave the relatively agreed results and considered to give the accurate moisture content. Atmospheric oven drying and infrared balance methods resulted in higher moisture content than methods mentioned above, because of the thermal decomposition of solid. Calibration of the moisture data of atmospheric oven drying method into the vacuum oven data was undertaken. The thermodecomposable solid fraction was high in onion, radish, green onion and carrot, and was in the range of 8.0-11.7% of the total solid in these products.

• Journal of the Korean Society of Combustion
• /
• v.13 no.2
• /
• pp.23-32
• /
• 2008

Gasification characteristics in the fluidized bed reactor are essential for the design of a gasification furnace to optimize the operation condition. Moisture content of the solid fuel is one of the important factors to influence directly the gasification characteristics. So it is necessary to investigate the effect of moisture content of solid fuel in partial oxidation condition. Gasification characteristics are investigated with results from thermogravimetric analyzer and lab-scale fluidized bed reactor for wood and RDF samples along with changing moisture contents. Additionally lab-scale fluidized bed reactor was run continuously and gas concentrations at the exit were measured. It is observed that the rate of reaction in partial oxidation condition is between the results from the combustion environment and from the inert condition. Moisture content in a particle slows down the heating rate of a particle. So, reaction is delayed by the moisture content. However, RDF samples those are easy to break-up don't show the effect of moisture content. The result of continuous operation condition shows that proper moisture content promotes gasification because steam from the particles helps gasification of the solid fuel. A simulation to predict the syn-gas composition was conducted by the Aspen Plus process simulator. The cold gas efficiency of the experiment was compared with results from the simulation.