• Culinary science and hospitality research
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• v.24 no.1
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• pp.105-113
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• 2018

In this study, optimized pre-treatment conditions were investigated to improve the quality of gochujang apple jangachi. The moisture content was decreased by 14% in 60% sugar solution and 17% in 30% salt solution during 12 hours. On the one hand, in the case of dry sugar and salt method, moisture content was decreased rapidly by 20% and 24%, respectively during 12 hours. Compared with the sugar and salt solution method, the dry sugar and salt method was more effective in reducing moisture content during 12 hours. In the case of osmotic dehydration of the apple parts in the dry sugar method, the moisture content of the flesh, flesh including peel, and peel of apple decreased by 23%, 20%, and 16%, respectively during 6 hours. However, in the dry salt method, the moisture content of the flesh, flesh including peel, and peel of apple decreased by 19%, 12% and 13%, respectively during 2 hours. During this time, the pH tended to decrease, regardless of the presence of sugar and salt. Total acidity was slightly increased in the case of salt. In hot air drying after osmotic dehydration, the moisture content of flesh including peel of apple decreased from 64% and 67% to 31% and 27%, respectively at 90 minutes, and from 64% and 67% to 11% and 18% at 150 minutes, respectively. The moisture content of the peel decreased from 51% to 10% at 120 minutes. As a result of the sensory evaluation, the overall acceptance of the flesh and flesh including peel was highly evaluated, resultantly, the products were considered to be suitable for the production of gochujang apple jangachi.

• Journal of Adhesion and Interface
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• v.8 no.3
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• pp.16-23
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• 2007

Polyester fabrics and knits were corona treated with different current intensity (5, 10, 15, 20 A) and feeding speed (5, 10, 15 m/min). We confirmed the surface change of polyester fabrics and knits using scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (XPS). And the change of physical properties through measuring the tensile strength, dry and wet bonding strength. Thermosetting reactive polyurethane hot melt adhesive was used in the adhesion of polyester fabrics and knits. Functional groups were introduced on PET fabrics and knits surface by treating the PET fabrics and knits in air atmosphere with corona discharge, and take placed unevenness, the result adhesion was improved. When consider both dry and wet bonding strength, we think that appropriate conditions in the PET fabrics corona treatment are feeding speed 10 m/min, current intensity 15 A and appropriate conditions in the mesh type PET knits corona treatment are feeding speed 10 m/min, current intensity above 10 A.

• Transactions of Materials Processing
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• v.31 no.3
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• pp.160-166
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• 2022

The purpose of this study is to investigate the effects of combined addition of Ca and Y on the precipitation and age-hardening behavior of an extruded AZ91 alloy by conducting the aging treatment at 200 ℃ for hot-extruded AZ91 and AZ91-0.3Ca-0.2Y alloys. In the AZ91 alloy, many Mg₁₇Al₁₂ discontinuous precipitate (DP) bands formed during air cooling immediately after extrusion are present, whereas in the AZ91-0.3Ca-0.2Y alloy, a few DP bands and numerous Al₂Y, Al₈Mn₄Y, and Al₂Ca phase particles are distributed along the extrusion direction. The peak-aging time of the AZ91-0.3Ca-0.2Y alloy is 16 hours, twice that of the AZ91 alloy. Although both alloys have similar hardness before aging treatment, the hardness after peak-aging treatment (i.e., peak hardness) of the AZ91-0.3Ca-0.2Y alloy is higher than that of the AZ91 alloy, as 93.1 and 88.7 Hv, respectively. The microstructures of both peak-aged alloys comprise DPs and continuous precipitates (CPs). However, the peak-aged AZ91-0.3Ca-0.2Y alloy has a smaller amount of DPs and a larger amount of CPs than the peak-aged AZ91 alloy. Additionally, the inter-particle spacings of DPs and CPs in the former are significantly narrower than those in the latter. These results demonstrate that the addition of small amounts of Ca and Y to a commercial AZ91 alloy considerably affects the formation rate, size, and amount of CPs and DPs during aging and resultant age-hardening behavior.

• Journal of Adhesion and Interface
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• v.7 no.3
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• pp.26-33
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• 2006

Nylon fabrics were corona treated with different current intensity (5, 10, 15, 20 A) and feeding speed (5, 10, 15 m/min). We confirmed the change of nylon fabrics surface using X-ray diffraction apparatus, scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (ESCALAB). And the change of physical properties through measuring the tensile strength, tear strength, bonding and wet bonding strength. Thermosetting reactive polyurethane hot melt adhesive was used in the adhesion of nylon fabrics. Functional groups were introduced on nylon fabric surface by treating the fabrics in air atmosphere with corona discharge, and the result adhesion was improved. Bonding strength of the nylon fabric treated with corona was increased with increasing current intensity and decreasing feeding speed.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.378-385
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• 2002

Oxidant radicals are implicated as a causal factor in the pathogenesis of neurobiological disorders and neuro-degenerative diseases. The objective of this study was to investigate the antioxidant activity of edible plants against oxidative stress in bovine brain tissue. Fifty five kinds of edible plants grown in Korea were dried either by freeze-drying or hot-air drying (7$0^{\circ}C$), and evaluated for their antioxidant activity by measuring TBARS (thiobarbituric acid-reactive substances) in brain homogenates subjected to Fe$^{+2}$_mediated lipid peroxidation with or without the addition of botanical extracts. Heat-drying decreased the antioxidant activity of most plant extracts by 10~81%, compared with freeze-drying. However, Aruncus americanus, Ligularia stenocephala, Artemisia princceps var. orientalis, Petasites japonicus and Aster scaber showed very strong antioxidant activities regardless of processing, with or without heat treatment. The $IC_{50}$/ values of the methanol extracts from these edible plants were in the range of 0.093~0.379 mg/$m\ell$, which was lower than that of ascorbic acid (0.79 mg/$m\ell$). Thermal processing of some edible plants enhanced their antioxidant activity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.279-286
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• 2005

This study presents experimental results on the heat transfer coefficients in the film boiling region of spray cooling for actual metallurgical process. In this study, the heat flux distributions of a two dimensional dilute spray impinging on a hot plate were experimentally investigated. A stainless steel block was cooled down from intial temperature of about $800^{\circ}C$ by twin fluid (air-water) flat spray. It was found from the experimental results that the heat transfer area was classified into the stagnation region and wall-flow region. In the stagnation region, the experimental data of local heat transfer coefficient was closely correlated with the local droplet-flow-rate supplied from the spray nozzle directly. Thus, the local heat transfer coefficients are in good agreement with the predicted values from the correlations proposed by our previous study. In wall-flow region, however, remarkable differences are observed between experimental data and predicted values because the number of rebound droplets increase with increasing the distance from the stagnation point.

• Korean Journal of Materials Research
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• v.27 no.9
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• pp.477-483
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• 2017

This present study deals with the microstructure and tensile properties of 600 MPa-grade high strength and seismic resistant reinforcing steels. The high strength reinforcing steel (SD 600) was fabricated by Tempcore processing, while the seismic resistant reinforcing steel (SD 600S) was air-cooled after hot-rolling treatment. The microstructure analysis results showed that the SD 600 steel specimen consisted of a tempered martensite and ferrite-pearlite structure after Tempcore processing, while the SD 600S steel specimen had a fully ferrite-pearlite structure. The room-temperature tensile test results indicate that, because of the enhanced solid solution and precipitation strengthening caused by relatively higher contents of C, Mn, Si and V in the SD 600S steel specimen, this specimen, with fully ferrite-pearlite structure, had yield and tensile strengths higher than those of the SD 600 specimen. On the other hand, the hardness of the SD 600 and SD 600S steel specimens changed in different ways according to location, dependent on the microstructure, ferrite grain size, and volume fraction.

• Journal of the Korean Wood Science and Technology
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• v.16 no.1
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• pp.3-8
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• 1988

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.164-170
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• 2007

The Tancheon wastewater treatment plant(WWTP) in Seoul using anaerobic digestion to reduce the outlet sludge produces anaerobic digester gas which contains 65% $CH_4$ and 35% $CO_2$. The gas purification equipment was installed and operated to use Anaerobic Digester Gas(ADG) as a fuel for molten carbonate fuel cell(MCFC). The processes consist of the desulfurizer and the adsorption tower to remove $H_2S$ and siloxane in the gas. The gas purification equipment removed virtually over 95% of $H_2S$ and over 99% of siloxane. Results has demonstrated that the fuel cell can produce electrical output and hot water with negligible air emissions of CO, NOx and $SO_2$. The site provides the first opportunity in Korea for demonstrating Molten carbonate fuel cell(MCFC) which the digester gas was applied to the fuel gas.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.153-163
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• 2021

This study was conducted to examine the effects of starch noodles (dangmyeon; SNs) with different starch sources and porcine intestines (PIs) with different pH on the rehydration stability of Korean blood sausage (sundae). Mungbean SN3 and PI3 (pH 9.18) showed significantly higher values of 80.69%-91.67% and 79.66%-80.98%, respectively, regardless of the drying methods (hot air, vacuum and freeze drying) (p<0.05). A number of larger pores were observed only in the cross-section of the freeze dried SN and PI through SEM. SN2 (potato starch) and PI3 (pH 9.18) showed lower expansion (⁎ΔL 6.90 mm) and higher expansion ratio (⁎ΔL 26.29 mm), respectively, after rehydration of freeze dried sample (p<0.05). From the application of SN2 (potato starch) and PI (0.5%-2.0% Na-pyrophosphate) to freeze dried sundae manufacturing, higher rehydration stability of more than 91.5% was obtained. These results suggested that potato SN and treatment of PI with Na-pyrophosphate is useful for desirable rehydration stability of freeze dried sundae.