• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.65-71
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• 1997

The energy supplied by motor of extruder, being known mostly to be dissipated as heat, was classified into two kinds of energy: a thermal energy by heat dissipation and a purely mechanical energy. The thermal energy was defined as a energy in terms of temperature rise and the mechanical energy as the motor energy minus the heat dissipated energy. A method to derive the thermal energy and the relative mechanical energy (the mechanical energy calculated regarding the mechanical energy at the lowest screw speed as zero) under the condition of constant barrel temperature was developed by which an extrusion case was analyzed. When extruding com grits with moisture $(27{\sim}37%)$ at low barrel temperature $({\leq}80^{\circ}C)$, the thermal energy slightly increased with increase in the moisture content, whereas the relative mechanical energy increased to a great extent. When increasing the screw speed, the thermal energy was nearly kept constant, whereas the relative mechanical energy largely varied. It is concluded that as the moisture content increases, the role of the mechanical energy becomes more effective than the heat energy dissipated from the motor energy.

• Korean Journal of Community Nutrition
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• v.23 no.2
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• pp.93-101
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• 2018

Objectives: With the increasing number of single households and so-called Honbab-jok, those who eat alone, people tend to enjoy convenient and simple meals, such as single dish meals. This study was performed to provide data on the energy and nutrient content, and nutritional adequacy of single-dish meal. Methods: From the literature reviews, 61 types of single-dish meals were selected, and divided into 4 groups (steamed rice, noodle, porridge, and sandwich burger), and a further 11 sub-groups (bibimbab, fried rice, topped rice, rolled rice/ warm noodle, cold noodle, seasoned noodle, dukgook/ porridge/, and sandwich, burger). In addition, 382 junior high school students from Gyeonggi, Sejong, Jeonbuk, and Chungnam areas were recruited for the survey. The survey questionnaires were composed of the characteristics, preference, and intake frequency of single-dish meals. The representative energy content (arithmetic mean) of single-dish meals were calculated, and compared with the energy contents of preference and intake frequency-weighted values adjusted. The representative nutrient contents, energy contribution ratio, and INQ (index of nutritional quality) of a single-dish meal were calculated for a nutritional adequacy evaluation. Results: The study subjects considered a single-dish meal as tasty, simple and fast to prepare, inexpensive, nutritious, and no low calorie food. The preference scores of all but 1 sub-group of singledish meals were ${\geq}5.00$ (5.00~5.97), and 1 sub-group (porridge) was 4.67 on a 7-point scale. The intake frequency of 11 sub-groups were 0.31~1.71/week, porridge was the lowest at 0.31 and warm noodles was the highest at 1.71. Fried rice, rolled rice, and warm noodle' intake frequency were ${\geq}1/week$. The representative energy of steamed rice, noodle, sandwich burger were 443, 429, and 428 kcal, respectively, and that of porridge was 264 kcal. Less than 5% differences in the representative energy of 4 groups were observed when adjusted for the preference or intake frequency-weighted values. The energy contribution ratio of macro-nutrients calculations showed that porridge was a high carbohydrate and low fat food, whereas sandwich burger were high fat and low carbohydrate foods. The INQ of calcium and vitamin C were less than 1.0 in all 4 food groups, but the INQ of protein and thiamin were > 1.0 in all 4 single-dish food groups. Conclusions: The representative energy in the 4 groups of single-dish meal was 264~450 kcal, which is a rather low calorie meal, and the energy contribution ratio of macro-nutrients were inadequate. The protein and thiamin levels were sufficient but the calcium and vitamin C levels were insufficient in all 4 groups of a single-dish meal judged by the INQ. The additional intake of fruits and milk dairy products between meals with a single-dish meal, supply of calcium and vitamin C may increase, which will result in an improved nutritional balance.

• Journal of Powder Materials
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• v.1 no.2
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• pp.181-189
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• 1994

The compacts of pure and phosphorus-coated iron powder with 0~0.8%C were sintered at $1100^{\circ}C$ for 40 min. in cracked ammonia gas atmosphere. The tensile and impact strengths were measured and the relationship of the results with carbon content, phosphorus, quenching and tempering was investigated. The results obtained can be summarized as follows : (1) The tensile strength of sintered compacts increased slowly with carbon content. Increase in tensile strength by heat treatment was evident especially in the low carbon specimen. The specimen with phosphorus showed higher strength compared to pure iron compacts value. (2) No inflection point of elasticplastic deformation on stress-strain curve was observed in sintered steel. The elastic modulus of sintered steel had the same tendency as tensile strength. But the elongation showed the opposite tendency. (3) The impact absorption energy of sintered steel without addition of phosphorus decreased successively with carbon content and by quenching and tempering. On the contrary, addition of phosphorus resulted in an increase of the impact absorption energy. Quenching and tempering did not affect the impact energy especially in high carbon content. (4) The main fracture source was pore in specimen and the propagation of crack occured mostly along the grain boundaries. But the intragranular fracture was also observed in high carbon, quenched and tempered specimen, and especially in the specimen with phosphorus.

• Journal of Powder Materials
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• v.17 no.2
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• pp.130-135
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• 2010

Sm-16.7wt%Co alloy powders were prepared by high energy ball milling under the conditions of various milling time and the content of process control agent (PCA), and their microstructure and magnetic properties were investigated to establish optimum processing conditions. The initial powders employed showed irregular shape and had a size ranging from 5 to $110\;{\mu}m$. After milling for 5 h, the shape of powders changed to round shape and their mean powder size was approximately $5\;{\mu}m$, which consisted of the agglomerated nano-sized particles with 15 nm in diameter. The coercivity was reduced with increasing the milling time, whereas the saturation magnetization increased. As the content of PCA increased, the powder size minutely decreased to approximately $7\;{\mu}m$ at the PCA content of 10 wt%. The XRD patterns showed that the main diffraction peaks disappeared apparently after milling, indicating the formation of amorphous structure. The measured values of coercivity were almost unchanged with increasing the content of PCA.

• Journal of Biosystems Engineering
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• v.14 no.3
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• pp.207-214
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• 1989

In this study, impact force and angular displacement of the pendulum were measured by the load cell and potentiometer. Mechanical behavior of rough rice under impact loading was able to analyze precisely and efficiently, because measured data were accumulated and handled by the automatic data acquisition system making use of microcomputer system. Impact force and angular displacement were measured with a resolutiln of 1/1500 seconds in time. Mechanical behavior such as force and energy at rupture point of Japonica type and Indica type rough rice were measured with this system. After impact loading, the damage of rough rice was examined with the microphotograph and an allowable impact force was measured. The results obtained in this study are summarized as follows. 1. Machanical behavior of rough rice under impact loading was analyzed precisely and efficiently because measured data were accumulated and handled by this data acquisition system. 2. Rupture force and rupture energy of rough rice were appeared to be the lowest value in the range of 16 to 18 % moisture content, and rupture force and rupture energy of Japonica type were higher than those of Indica type in each level of moisture content. 3. From the result of the damage examined after the impact loading, allowable impact force was the lowest in the range of 16 to 18 % moisture content, and the value of the allowable impact force of Japonica type was higher than that of Indica type in each level of moisture content.

• Earthquakes and Structures
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• v.1 no.2
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• pp.147-162
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• 2010

The ground acceleration measured at a point on the earth's surface is composed of several waves that have different phase velocities, arrival times, amplitudes, and frequency contents. For instance, body waves contain primary and secondary waves that have high frequency content and reach the site first. Surface waves are composed of Rayleigh and Love waves that have lower phase velocity, lower frequency content and reach the site next. Some of these waves could be of more damage to the structure depending on their frequency content and associated amplitude. This paper models critical earthquake loads for single-degree-of-freedom (SDOF) inelastic structures considering evolution of the seismic waves in time and frequency. The ground acceleration is represented as combination of seismic waves with different characteristics. Each seismic wave represents the energy of the ground motion in certain frequency band and time interval. The amplitudes and phase angles of these waves are optimized to produce the highest damage in the structure subject to explicit constraints on the energy and the peak ground acceleration and implicit constraints on the frequency content and the arrival time of the seismic waves. The material nonlinearity is modeled using bilinear inelastic law. The study explores also the influence of the properties of the seismic waves on the energy demand and damage state of the structure. Numerical illustrations on modeling critical earthquake excitations for one-storey inelastic frame structures are provided.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.77-80
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• 2011

In this study, we measured changes in the lignin content of acidified lignocellulosic biomass such as rice straw, saw dust, chestnut shell and peanut hull and analyzed the conversion property to cellulosic ethanol. It turns out that the lignin content increases in chestnut shell, rice straw, saw dust, peanut hull order and the conversion property to cellulosic ethanol is superior in the reverse order. Thus, the removal of lignin by acidification is necessary. In addition, as the concentration of sulfuric acid increases, the lignin content decreases and the yield of cellulosic ethanol increased. The optimum concentration of sulfuric acid is 20 wt%.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4270-4274
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• 2011

A method is proposed for determining chromium content in the carbon steel pipes of a nuclear power plant (NPP) to evaluate wall thinning caused by flow-accelerated corrosion (FAC). A flat file was used to obtain filings samples. To assess sampling quality, a disk form of SRM 1227 was ground with the flat file, and the amount of Cr in the filings was determined by ICP-AES. The content of chromium in the filings of SRM 1227 was estimated as six times higher than the certified value due to the contamination of chromium in the file. To eliminate chromium contamination from the file, it was coated with WC-12Co using high-velocity oxygen-fuel (HVOF) spraying systems. After obtaining filings samples using the coated file, Cr content in four types of disk-form SRMs was determined by ICP-AES. The recoveries of Cr in the disk-form SRMs were in the range of 95.4-102.6%, with relative standard deviations from 0.43 to 3.0%. The Cr contents in the filings collected from the used outlet headers of the nuclear power plants using the flat file coated were in the range of 0.11-0.19%.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.55-63
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• 1999

For understanding the radiation environment in the land of Korea and acquiring baseline data to be referred to at the time of a nuclear accident, cultivated soils in the $0{\sim}15cm$ layer were sampled at 33 sites scattered all over the country and $^{137}Cs$ concentrations were measured by $\gamma$-spectrometry. The soil $^{137}Cs$ concentrations were in the range of $0.7{\sim}17.7$ Bq/kg-dry in the paddy field and $1.2{\sim}27.8$ Bq/kg-dry in the upland field, The means were 6.9 Bq/kg-dry and 9.9 Bq/kg-dry, respectively. In the paddy field, the soil $^{137}Cs$ concentration was positively correlated to the organic matter content and negatively correlated to the clay content. In the upland field, it was positively correlated to the cation exchange capacity. It was revealed that soil organic matter play an important role in the change of soil $^{137}Cs$ concentration.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.375-381
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• 2012

Two experiments were conducted to establish a digestible energy (DE) content prediction model of rapeseed meal for growing-finishing pig based on rapeseed meal's chemical composition. In experiment 1, observed linear relationships between the determined DE content of 22 rapeseed meal calibration samples and proximate nutrients, gross energy (GE) and neutral detergent fiber (NDF) were used to develop the DE prediction model. In experiment 2, 4 samples of rapeseed meal selected at random from the primary rapeseed growing regions of China were used for testing the accuracy of DE prediction models. The results indicated that the DE was negatively correlated with NDF (r = -0.86) and acid detergent fiber (ADF) (r = -0.73) contents, and moderately correlated with gross energy (GE; r = 0.56) content in rapeseed meal calibration samples. In contrast, no significant correlations were found for crude protein, ether extract, crude fiber and ash contents. According to the regression analysis, NDF or both NDF and GE were found to be useful for the DE prediction models. Two prediction models: DE = 16.775-0.147${\times}$NDF ($R^2$ = 0.73) and DE = 11.848-0.131${\times}$NDF+0.231${\times}$GE ($R^2$ = 0.76) were obtained. The maximum absolute difference between the in vivo DE determinations and the predicted DE values was 0.62 MJ/kg and the relative difference was 5.21%. Therefore, it was concluded that, for growing-finishing pigs, these two prediction models could be used to predict the DE content of rapeseed meal with acceptable accuracy.