• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.8-14
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• 2010

In this study, we experimentally investigated a compression ignition engine operated with Bio-diesel blended LPG fuel. In particular, the performance, emissions characteristics (including total hydrocarbon, carbon monoxide, nitrogen oxides, and carbon dioxides emissions), and combustion stability of a CI engine fueled with Bio-diesel blended LPG fuel were examined at 1500 rpm. The percentage of Bio-diesel in the fuel blend ranged from 20-60%. The results showed that stable engine operation was possible for a wide range of engine loads up to 40% Bio-diesel by mass. When the Bio-diesel content was increased, leading to a decrease in the lower heating value of the blended fuel, the cetane value increased, resulting in a advanced start of heat release. Exhaust emission measurements showed that THC and CO emissions were increased when using the blended fuel at low engine speeds due to partial burn from over-mixing. NOx emission was emitted less at lower loads and more at higher loads.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.235-240
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• 2014

In this study, the torrefaction of food waste was conducted to characterize its product, to find out effect of the operating temperature and to assess the feasibility of being used as fuel. The operating temperature was varid from $180^{\circ}C{\sim}270^{\circ}C$ and heat was provided by using nitrogen gas or waste oil heat carrier. The solid yield and moisture content were reduced were reduced as temperature increased. The moisture content reduction and thermochemical conversion were observed at higher than $240^{\circ}C$. At low operating temperature, heat transfer efficiency was higher with wast oil heat carrier. As temperature increases, there was not difference in heat transfer efficiency of two different heating methods. The lower heating value product was increased from 660 to 6,400 Kcal/kg with nitrogen gas and 6,890 Kcal/kg with waste oil heat carrier. The elemental analysis indicates that, as temperature increases, the carbon content of product increases and oxygen content decreases. From the analysis of O/C and H/C, the torrefaction product was close to low grade coal. The characteristics of fuel converted from the food subsequent thermochemical treatment.

• KIEAE Journal
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• v.15 no.1
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• pp.77-82
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• 2015

The purpose of this study is to compare the thermal insulation performance of windows according to the formation of air layer and to evaluate its energy efficiency on a selected standard house. A thermal insulation test, KS F 2278 was used to measure U-values (Heat transmission coefficients) for the following three cases: the first case (Case 1) is a Low-E pair glass (Argon injected), the second case (Case 2) is a Low-E pair glass with the air cap attached on the glass surface, and the third case (Case 3) is a Low-E pair glass, on the frame of which the air cap is attached. The evaluation of the energy efficiency was conducted according to a building energy calculation method from ISO 13790, calculation of energy use for space heating and cooling, using the U-values obtained from the thermal insulation tests. As results of the tests, the U-values of Case 1, Case 2, and Case 3 were $1.668W/m^2{\cdot}K$, $1.568W/m^2{\cdot}K$, and $1.319W/m^2{\cdot}K$ respectively. The Case 2 had about 5.9% lower value than the Case 1, and the Case 3 had about 20.9% lower value than the Case 1. It seems that the thermal performance of the windows is attributed to an increase of the heat resistance and the thickness of air layer. An evaluation of the energy efficiency of the three cases on the selected standard house showed that the amount of heating energy demand per unit area was $7.776kWh/m^2{\cdot}yr$ for the Case $1,6.856kWh/m^2{\cdot}yr$ for the Case 2, and $4.856kWh/m^2{\cdot}yr$ for the Case 3. This study suggests that the formation of air layer (by using air cap) and its thickness should reduce the heat energy demand and thus improve the energy saving efficiency

• Food Science and Preservation
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• v.10 no.1
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• pp.75-79
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• 2003

Total nitrogen(TN) contents in all samples were in the range of 308.3 to 925.9 mg% and TN value of kanjang prepared with high pressure(HPK)-heated bean was lower than that of normal pressure(NPK) and steam(SPK)-heated bean. TN content was slightly increased according to the heating time of bean. Amino type nitrogen(AIN) contents in all samples were in the range of 133 to 451.5 mg％ and AIN value of NPK(451.5 mg%) was higher than that of HPK(133∼171.5 mg%) and SPK(178.9∼224 mg%). Ammonia type nitrogen(AON) contents in all samples were in the range of 23.5 to 142.0 mg% and AON value of HPK was lower than that of HPK and SPK. Free amino acid(FA) contents in all samples were in the range of 133 to 451.5 mg%, and then FA content of NPK was higher than that of SPK(178.9∼224 mg%) and HPK(133 ∼171.5 mg%). Lightness(L) value of Hunter color in all samples were in the range of 45.13 to 49.08 and was similar with each other. Redness(a) and yellowness(b) value were in the range of 25.30∼34.43 and 52.55∼74.13, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.698-704
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• 2014

This study was conducted to investigate the effects of chestnut inner shell powder on antioxidant activities and quality characteristics of pork patties. Patties were prepared with different amounts of chestnut inner shell powder (0, 1, 3, and 5% of pork quantity). The total phenol contents and DPPH free radical scavenging activities of the patties significantly increased with increasing amount of chestnut inner shell powder. The moisture content and pH of row patties were not significantly different between the control group and treatment groups. The cooking loss rate significantly decreased with increasing chestnut inner shell powder amount. Reduction ratio of the diameter of experimental patties was lower than that of the control patties, although it was not significant. As the content of chestnut inner shell powder increased, L-value decreased while a-value increased in both row patties and cooked patties. However, b-value changed upon heating. The b-value of row patties also increased with increasing chestnut inner shell powder content, whereas the b-value of cooked patties decreased. The hardness, chewiness, gumminess, and cohesiveness of the control group were lower than those of the treatment group. The consumer acceptability score for patties with 1% chestnut inner shell powder was higher than that for patties in terms of overall preference, appearance, color, and texture. Further, overall preference, appearance, and color for patties with chestnut inner shell powder 3% were higher than those of the control group. We suggest that chestnut inner shell can be improve the quality characteristics and consumer acceptability of pork patties, as well as the development of health-oriented meat products.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.271-282
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• 2020

Sewage treatment plants are social infrastructure of cities. The sewage distribution rate in Korea is reaching 94% based on the sewage statistics based in the year of 2017. In Korean sewage treatment plants, use of PAC (Poly Aluminum Chloride) accounts for 58%. It contains a large amount of impurities (heavy metal) according to the quality standards, however, there have been insufficient efforts to reinforce the standards or technically improve the quality, which resulted in secondary pollution problems from injecting excessive coagulant. Also, the increase in the use of chemicals is leading to the increases in the annual amount of sewage sludge generated in 2017 and the need to reuse sludge. As such, this study aims to verify the possibility of reusing sludge by evaluating the stability of heavy metals based on the injection of coagulant mixture during water treatment which uses the torrefield wood powder and natural materials, and evaluating the sedimentation and heating value of sewage sludge. As a result of analyzing heavy metals (Cr, Fe, Zn, Cu, Cd, As, Pb, and Ni) from the coagulant mixture and PAC (10%), Cr, Cd, Pb, Ni, and Hg were not detected. As for Zn, while its concentration notified in the quality standards for drinking water is 3 mg/L, only a small amount of 0.007 mg/L was detected in the coagulant mixture. Maximum amounts of over double amounts of Fe, Cu, and As were found with PAC (10%) compared to the coagulant mixture. Also, an analysis of sludge sedimentation found that the coagulant mixture showed a better performance of up to double the speed of the conventional coagulant, PAC (10%). The dry-basis lower heating value of sewage sludge produced by injecting the coagulant mixture was 3,378 kcal/kg, while that of sewage sludge generated due to PAC (10%) was 3,171 kcal/kg; although both coagulants met the requirements to be used as auxiliary fuel at thermal power plants, the coagulant mixture developed in this study could secure heating values 200 kal/kg higher than the counterpart. Therefore, utilization of the coagulant mixture for water treatment rather than PAC (10%) is expected to be more environmentally stable and effective, as it helps generating sludge with better stability against heavy metals, having a faster sludge sedimentation, and higher heating value.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.975-984
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• 2018

Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. A 500 g of Quercus mongollica which grounded 0.8~1.4 mm was processed into bio-oil via fast pyrolysis for 2 seconds at $550^{\circ}C$. The esterification consists of treating pyrolysis oil with a high boiling alcohol like n-butanol at $70^{\circ}C$ under reduced pressure (100 hPa). All products are analyzed for water mass fraction, viscosity, higher heating value, pH, FT-IR and GC/MS. The water mass fraction can be reduced by 91.4 % (from 31.5 % to below 2.7 %), the viscosity by 65.8 % (from 36.5 to 12.5 cP) and the higher heating value can be increased by 96.8 % (from 3,918 to 7,712 kcal/kg), the pH by 1.3 (from 2.7 to 4.0). FT-IR and GC/MS analysis indicated that labile acids, aldehydes, ketones and lower alcohols were transformed to stable target products. Using this approach, the water content of the pyrolysis oil is reduced significantly. These improvements should allow the utilization of upgraded pyrolysis liquids in standard boilers and as fuel in CHP (Combined heat and power) plants.

• The Korean Journal of Food And Nutrition
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• v.22 no.3
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• pp.387-395
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• 2009

This study was conducted to investigate the effects of starch concentrations and heating conditions on the gel characteristics of arrowroot starch. Arrowroot starch gels with various pHs, and starch concentrations, were prepared using different temperatures and heating times, and then stored for 24 hrs at $4^{\circ}C$. The hardness of sample gels made at pH 2.0 and 4.0 increased as the starch concentration increased from 7% to 10%, with the maximum value of 94 N being obtained when the gel was prepared at pH 4.0 with a starch concentration of 10%. The maximum hardness of samples prepared with concentrations of starch ranging from 7~9% appeared at $80^{\circ}C$, regardless of the heating temperature and time. Furthermore, the hardness of samples prepared at greater than $100^{\circ}C$ was relatively lower than that of samples prepared at other temperatures. When a starch concentration of 8% was used, the degree of gelatinization(DR) increased as the heating temperature increased, with the maximum value of DR being about 76% at $120^{\circ}C$, regardless of heating time. After storage for 24 hrs, the hardness of samples prepared at $70^{\circ}C$, $80^{\circ}C$ and $90^{\circ}C$ appeared to decrease, while that of samples prepared at $100^{\circ}C$, $110^{\circ}C$ and $120^{\circ}C$ increased. The correlation between hardness and the degree of gelatinization or retrogradation was very high when samples were prepared at $80^{\circ}C$ with a starch concentration of 9%, as indicated by a correlation coefficient of greater than 0.95. Overall, the microstructures of freeze-dried arrowroot starch gel were composed of a continuous network of amylose and amylopectin with fragmented ghost structures in an excluded phase, but these ghost structures were more evident after storage and with increased heating temperature.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.762-771
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• 1987

Friction welding is a fusion process in which the necessary heat is generated by clamping one of the two pieces to be welded in a stationary chuck and rotating the other at high speed with an axially applied load. It is essentially a variation of the pressure welding process but utilizes a novel heating method. In addition to the foregoing advantages, it has also been reported excellent for welding dissimilar materials. Therefore, this study reported on investigating the strength behavior for the frictionally welded domestic structural steel SM45C and SUS304. The results obtained by the experiments are as follows. (1) The highest tensile strength of the best friction welded specimen (B4) is about 3% lower than that of SM-45C base metal, and 9% lower than that of SUS304 base metal. The heat treated specimens (850.deg.C 1hr A.C) have almost same value of tensile strength. (2) The strain of SM45C base metal is 27.3% and that of SUS304 is 42%, that of the best friction welded specimen (B4) appeared as 11.9% which is about 50% lower than the base metal, so, this same phenomenon apeared in all the other welding conditions. (3) The bending strength of SM45C base metal is 123kgf/mm$^{2}$ and that of SUS304 is 127kgf/mm$^{2}$. The best specimen (B4) appeared as 121kgf/mm$^{2}$ which is almost same bending strength for both base metals. (4) The friction welded condition involving maximum strength is determined by P$_{1}$=8kgf/mm$_{2}$, P$_{2}$=22kgf/mm$_{2}$, T$_{1}$=10sec, T$_{2}$=2sec, and amount of upset 7.6mm. (5) The interface of two dissimilar materials are mixed strongly, and welded zone is about 1.03mm and also the heat affected zone is about 2.36mm at SM45C while about 1.85mm at SUS304, therefore the welded zone and heat affected zone are very narrow to compare with those of the other welding materials.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1750-1757
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• 2000

A total of 864 broiler chicks were used at Kansas State University and the University of Nebraska to determine the effects of heat treatment of two soybean genotypes on the growth performance. The soybeans were Williams 82 variety with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Heat treatment (autoclaving at $121^{\circ}C$ and $1.1kg/cm^2$) was applied for 0, 3, 6, 12, 18, and 24 min, resulting in a $2{\times}6$ factorial arrangement of treatments. Station and station treatment effects occurred, indicating that response in nutritional value of the soybean genotypes to heat treatment varied from year to year and location to location. However, the interactions were in magnitude of response rather than direction of response, with greater reductions in trypsin inhibitor concentrations for the soybeans heat processed at the Nebraska location. Pooled data indicated that -K supported greater (p<0.001) ADG, ADFI and gain/feed than the +K genotype. As the length of heat treatment increased, the ADG, ADFI, and the gain/feed ratio increased for chicks fed both soybean genotypes (p<0.0001). However, heating the -K soybeans resulted in a greater response in ADG, ADFI, and gain/feed than heating the +K soybeans (genotype heat treatment interaction, p<0.001). Pancreatic weights (mg pancreas/g of BW) of chicks fed -K soybeans were reduced compared to those from chicks fed +K (p<0.001). Increasing heat treatment decreased pancreas weights in chicks fed both soybean genotypes (p<0.001). Chicks fed heated soybeans in the Nebraska experiment had lower pancreatic weights than chicks fed heated soybeans in the Kansas experiment (station heat treatment interaction, p<0.0001). Chick growth performance was improved and pancreatic weights decreased by feeding raw -K soybeans versus raw +K soybeans, and by increasing heat treatment of both soybean genotypes. However, the response to heat treatment was not independent of genotype. Both +K and -K soybeans heated for 24 min supported similar ADG, ADFI, gain/feed, and pancreas weights, although chicks fed raw +K soybeans had lower growth performance than chicks fed -K soybeans. In conclusion, raw -K soybeans supported greater growth performance in broiler chicks than raw +K soybeans, although this advantage was lost when both soybean genotypes were heated for 24 min. Heat treatment of +K soybeans supported similar growth performance to heated -K soybeans, even though +K soybeans supported lower rates and efficiencies of gain than -K soybeans when fed raw.