• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.360-368
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• 2017

In order to investigate the durability of high performance polymer concrete composites, polymer concrete specimens were prepared using the ortho-type unsaturated polyester resin (UPR) and iso-type UPR as a polymer binder and the calcium carbonate and silica fine powder as a filler. The durability of polymer concrete specimens was measured by hot water resistance, chemical resistance, pore analysis and SEM observation. The compressive strength of the specimen using the iso-type UPR was higher than that of using the ortho-type UPR, and the compressive strength of the specimen using the silica fine powder was higher than that of using the calcium carbonate filler. From hot water resistance results, it was found that the specimen using the iso-type UPR was superior to that of using the ortho-type UPR and the specimen using the calcium carbonate filler was superior to that of using the silica fine powder. The compressive strength reduction rate was measured after the chemical resistance test and the sodium hydroxide solution showed the highest reduction rate, followed by sulfuric acid, hydrochloric acid and calcium chloride solutions. When using the alkaline solution of sodium hydroxide, the weight reduction rate of the specimen using calcium carbonate was lower than that of using silica fine powder, while for the acidic solutions of sulfuric acid and hydrochloric acid, the weight reduction rate of the specimen using the silica fine powder was lower than that of using calcium carbonate.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.4
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• pp.393-402
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• 1995

Experiments were conducted to evaluate the nutritive values of supplemental L-lysine, liquid and powder type, and DL-methionine in weanling pigs. For feeding trial, 165 weanling pigs were treated in 2 controls; 18 and 16% CP, 6 supplementations of lysine alone to 16% CP diets; 0.1, 0.2 and 0.4% of liquid and powder type each, and 3 supplementations of lysine + methionine to 15% CP diets; 0.05 + 0.025, 0.1 + 0.05 and 0.2 + 0.1%. Pigs were fed for 5 week to investigate the protein sparing effect of supplemental amino acid, and the optimal supplemental level. A metabolic trial included the measurements of digestibilities of dry matter, crude protein, crude fat, crude fiber, energy, phosphorus and amino acids. The liver acinar cell culture was conducted for the protein synthesis activity of the pigs fed each experimental diet. Supplementation of both type of L-lysine in 16% CP diet showed improved daily weight gain and feed efficiency which were compatible with those of pigs fed 18% CP diet. Groups fed liquid lysine did not differ from those fed powder type in growth performance. Supplementation of lysine and methionine to 15% CP diet did not improve growth performance of pigs to the extent that 18% CP diet was fed. In nutrient digestibility, 16% CP control diet showed significantly (p < 0.05) lower crude protein digestibility than any other treatments. Digestibilities of 16% CP diets with lysine supplementation were equal to that of 18% CP control, while digestibilities of 15% CP diets with the supplementation of lysine + methionine was inferior to that of 18% CP control. Supplementation of lysine alone reduced the nitrogen excretion compared to the none supplemented control groups. However, addition of lysine + methionine excreted more nitrogen than controls. Pigs fed diet supplemented with lysine alone, or lysine + methionine excreted less fecal phosphorus than those fed none supplemetation. Retained protein from liver tissue of pigs fed 18% diet was significantly (p < 0.05) greater than those fed 16% CP diet. A significant difference (p < 0.05) was observed in physical type of lysine. Feeding of powder type showed less secreted protein and greater retained protein in the culture of liver acinar cell. It is concluded that supplementation of lysine at the level of 0.1 to 0.2% can spare 2% of dietary protein and reduce nitrogen excretion by 19.3%. Also, no difference in nutritional values was observed between liquid and powder lysine in weanling pigs.

• Journal of Powder Materials
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• v.10 no.5
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• pp.349-352
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• 2003

This study examined the correlation of various operational factors including reaction temperature and the quantity of reductant and diluent with the characteristics of powder using $K_2$ TaF$_{7}$ as feed materials, Na as a reductant and KCl/KF as a diluent. Also to control the particle size and shape, external supply system developed, it can provide a feed material and a reductant at a fixed quantity and evaluated the characteristics of tantalum powder. When the external supply system was applied instead of the batch type process that charges feed material, reductant and diluent at the same time, it was possible to induce regular reduction reaction between feed material and reductant, which increased the recovery rate and reduced the mixture of impurities. In particular, the application of the external supply system enabled the control of reaction temperature and reaction speed according to the feeding rate of feed material during reduced reaction, and resultantly it enabled the manufacturing of granular-shaped powder with a regular granularity of 2∼3 ${\mu}{\textrm}{m}$ and purity of 99.5%.

• Resources Recycling
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• v.20 no.6
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• pp.37-42
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• 2011

Copper chip scrape has been occurred by cutting of copper pipe. The feasibility of copper chip scrape into the copper powder by milling was studied. Two milling type such as rod milling and horizontal balling milling were applied in this research. Copper chip can not fragmented into powder by using rod milling. In contrast to rod milling, copper chip can be changed into powder by horizontal ball milling for above 36 hours. It was found that recycling of copper chip scraps into copper powder by horizontal ball milling is possible and powder fraction percent ($75{\sim}150{\mu}m$) of milled copper chip for 48 hours is 25.3%.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.480-481
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• 2006

The n-type $(95%Bi_2Te_3-5%Bi_2Se_3)$ compound was newly fabricated by gas atomization and hot extrusion, which is considered to be a mass production technique of this alloy. The effect of powder size on thermoelectric properties of 0.04% $SbI_3$ doped $95%Bi_2Te_3-5%Bi_2Se_3$ alloy were investigated. Seebeck coefficient $({\alpha})$ and Electrical resistivity $(\rho)$ increased with increasing powder size due to the decrease in carrier concentration by oxygen content. With increasing powder size, the compressive strength of $95%Bi_2Te_3-5%Bi_2Se_3$ alloy was increased due to the relative high density. The compound with ${\sim}300\;{\mu}m$ size shows the highest power factor among the four different powder sizes. The rapidly solidified and hot extruded compound using $200[\sim}300{\mu}m$ powder size shows the highest compressive strength.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.324-331
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• 2014

The dispersion characteristics of AlN-4.5 wt% $Y_2O_3$ powder mixture by various dispersants were investigated in ethanol and methyethly-ketone (MEK) solvents. In general, the cationic polymer dispersants demonstrated superior dispersion of the powder as compared to the non-ionic ester-type dispersants or anionic phosphate-ester-based ones. The dispersion performance of the cationic polymer dispersants was sensitive to the type of solvent. An anhydric maleic-acid-based graft copolymer dispersant, AFB-1521, demonstrated a very good dispersion capability in ethanol but exhibited a much inferior dispersion in MEK. On the other hand, the dispersion of the powder mixture was very good with a phosphate-ester-based block polymer dispersant, BYK-111, in MEK solvent, while dispersionwas much degraded in ethanol.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.448-456
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• 1994

The reaction-sintered alumina and zirconia-alumina ceramics were fabricated from the Al/Al2O3 or Zl/ZrO2(Ca-PSZ) powder mixtures via the attrition milling. And the effects of the milling characteristics of used raw powders on reaction sintering were investigated. After attrition milling and isopressing at 400 MPa the Al/Al2O3 specimen was oxidated at 1200℃ for 8 hours followed by sintering at 1550℃ for 3 hours. Because mixed powders of flake-type Al with coarse alumina was much more effectively comminuted than the globular-type Al with coarse alumina powders, it's sintered body of more than 97% theoretical density was achived, but low contents of Al leads to relatively higher shrinkage of about 8%. And because coarse alumina particles was much more beneficial in cutting and reducing the ductile Al particles, using the coarse alumina powder was much more effective in reaction sintering. Fused Ca-PSZ powder was reaction sintered with Al at 1550℃ for 3 hours and low shrinkage ZrO2-Al2O3 composites were fabricated. But because Al/Ca-PSZ powder mixtures were not effectively milled the reaction sintering and densification was difficult. And the Ca ion in Ca-PSZ grains diffused into alumina grains during sintering so that the unstabilization of Ca-PSZ body was occured which gave the microcracks in the specimens.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.325-326
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• 2006

Using $6wt%Y_2O_3-2wt%Al_2O_3$ as sintering additives and Si as a raw powder, the continuously porous in-situ $Si_2N_2O-Si_3N_4$ bodies were fabricated by multi-pass extrusion process and their microstructures were investigated depending on the addition of carbon (0-9wt%) in the mixture powder. The introduction of $Si_2N_2O$ fibers observed in the unidirectional continuous pores as well as in the pore-frame regions of the nitrided bodies can be an effective method in increasing the filtration efficiency. In the case of no carbon addition, the network type $Si_2N_2O$ fibers with high aspect ratio appeared in the continuous pores with diameters of 150-200 nm. However, in the case of 9wt% C addition, the fibers were found without any network type and had diameters of 200-250 nm.

• Food Science of Animal Resources
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• v.43 no.6
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• pp.1031-1043
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• 2023

The purpose of this study was to investigate the functional properties of salt-soluble proteins obtained from Protaetia brevitarsis (PB) and Tenebrio molitor (TM) larvae, the interaction between these proteins and pork myofibrillar protein (MP) in a gel system. The gel properties of salt-soluble protein extracts showed that the PB had a higher viscosity than the TM protein. However, the TM protein had higher gel strength compared with the PB protein. The gelation characteristics of the pork MP gel systems added with lyophilized insect salt-soluble protein powder showed to decrease slightly viscosity compared with MP alone. Adding the TM or PB protein powder did not affect the pork MP's hydrophobicity and sulfhydryl group levels. Furthermore, the protein bands of the MP did not change with the type or amount of insect salt-soluble protein. The cooking yields of the pork MP gels containing PB or TM protein powder were higher than those without insect protein. Regardless of the type of insect salt-soluble protein added, the pork MP's gel strength decreased. Furthermore, as the level of insect powder increased, the surface protein structure became rough and porous. The results demonstrated that proteins extracted from PB and TM larvae interfered with the gelation of pork MP in a gel system.

• Journal of Powder Materials
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• v.21 no.4
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• pp.256-259
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• 2014

A magnetic powder, M-type barium hexaferrite (BaFe12O19), was consolidated with the spark plasma sintering process. Three different holding temperatures, $850^{\circ}C$, $875^{\circ}C$ and $900^{\circ}C$ were applied to the spark plasma sintering process with the same holding times, heating rates and compaction pressure of 30 MPa. The relative density was measured simultaneously with spark plasma sintering and the convergent relative density after cooling was found to be proportional to the holding temperature. The full relative density was obtained at $900^{\circ}C$ and the total sintering time was only 33.3 min, which was much less than the conventional furnace sintering method. The higher holding temperature also led to the higher saturation magnetic moment (${\sigma}_s$) and the higher coercivity ($H_c$) in the vibrating sample magnetometer measurement. The saturation magnetic moment (${\sigma}_s$) and the coercivity ($H_c$) obtained at $900^{\circ}C$ were 56.3 emu/g and 541.5 Oe for each.