• International Journal of Highway Engineering
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• v.7 no.3 s.25
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• pp.63-69
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• 2005

For many years, the compressive strength of concrete has been regarded as an important index in determining concrete pavement quality. The compressive strength of the sample cores from the field has been used as quality index of concrete pavement. However, this process is time consuming and requires a lot of labor. Recently, the M-E Design Methodology in the pavement design based on the elastic modulus has been adopted. Therefore, several NDT methodologies have been adopted for QA/QC in the field and for the pavement design. Among various NDT methods, the wave propagation method can be used to measure the elastic modulus of concrete because the wave velocity is directly related to the elastic modulus. Therefore, in this study the wave propagation method was used for estimating the concrete modulus. The relationship between the compressive strength measured in he laboratory and the elastic modulus measured by the wave propagation method was analyzed, and the compressive strength was estimated from the elastic modulus for various mix types. The results showed that the relationship between the elastic modulus and the compressive strength was observed and the relationship varied depending on the aggregate types.

• Food Science and Preservation
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• v.19 no.5
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• pp.626-632
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• 2012

In this study, the changes that occurred in the quality of minimally processed sliced Deodeok (Codonopsis lanceolata) in relation to the packing method during storage at $7^{\circ}C$ were investigated. The storage tests were conducted for seven days using PE sealing, but PP sealing and vacuum packaging preserved the Deodeok for 14 days. On the seventh day, the vinyl-packaged Deodeok showed a remarkable fall in quality with 4.5 °Brix, but the PP-sealed and vacuum-packaged Deodeok showed slight falls with 6.4 and $6.8^{\circ}Brix$, respectively. The PE- and PP-sealed Deodeok did not show significant differences in texture and moisture content for two days, and the moisture content was highest in the vacuum-packaged Deodeok during storage. In relation to the total viable cell and the coliform count, the vacuum-packaged Deodeok showed the lowest rate of increment during storage, followed by the others. Thus, the bubble-washed and vacuum-packaged minimally processed sliced Deodeok was found to have the best quality.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.51-57
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• 1992

The preservative effect of chitosan film packing on quality of lightly-salted and dried horse mackerel was studied. In preparation of chitosan film, blue crab shell chitosan was dissolved in dilute acetic acid$(1.0\%,\;v/v)$, filtered, and spreaded on plastic plate and dried at $50\pm2^{\circ}C$. The chitosan film thus obtained was neutralized with 1.0N NaOH for 2 hrs and dried at room temperature after washing several times with distilled water. The lightly-salted and dried horse mackerel product was prepared by drying for 4 hrs at $40\pm2^{\circ}C$ in hot air dryer after packing with the chitosan film. During storage at $5.0\pm0.5^{\circ}C$, moisture content of the product was higher than that of the reference, but contents of VBN(volatile basic nitrogen) , amino nitrogen, and TMA of the product on dry basis were lower than those of the reference. Viable cell count, TBA value, and peroxide value of the product were also lower than those of the reference. Judging from the result of sensory evaluation, the chitosan film packing in the storage of lightly-salted and dried horse mackerel was remarkably elongated shelf-life of the product. From the results of chemical and sensory evaluation, it was concluded that chitosan film packing was an effective method for retaining the quality of lightly-salted and dried horse mackerel.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.9-18
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• 2008

Curling is caused by the difference in the temperature and humidity by the depth of the slab in Jointed Plain Concrete Pavement. Slab curvature shape and size change due to curling exert a profound influence on the internal stress and roughness of the pavement, affecting structural and functional performance of the pavement. Direct measurement of the slab curvature entails many problems. Many measuring instruments have to be installed at the early-stage of the pavement construction, and the behavior of the slab curvature needs to be measured accurately from the early-stage. Moreover, the cost and technical difficulty are very formidable to measure the slab curvature. This study develops a measurement method for slab curvature in jointed concrete pavement at any given time by applying Power Spectrum Density Analysis and Inverse Fast Fourier Transformation to the profile data, that can be easily obtained at the construction field site. The effectiveness of this developed method is verified by measuring the profile data of the test road of jointed concrete pavement at an inland central expressway by the hour and by examining the result of extracting the slab curvature shape from this profile data. Additionally, the profile data of CRCP(Continuously Reinforced Concrete Pavement) sections on the same expressway were obtained and analyzed at the same time. The validity of the method developed for the slab curvature shape extraction is verified by comparing the result from the analysis of the profile data of CRCP sections with that from the analysis of the prof1Ie data of jointed concrete pavement sections.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.133-137
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• 1994

Functional properties of packaging films prepared with cellulose derivatives were measured. As a presolvation treatments of celluloses, 95% ethanol solution for methylcellulose (MC), hydroxypropyl-methylcellulose (HPMC) and ethylcellulose (EC) and water for hydroxypropyl cellulose (HPC) were used. For film sheeting, the ethanol concentration of final cellulose solution should exceed 50% for MC, HPMC and HPC and 80% for EC. Thickness and functionalities of the prepared films were varied by type, molecular weight and viscosity of the cellulose and kind of plasticizer used. Tensile strength of MC, HPMC and HPC films were $67.7{\sim}275.4\;MPa$, $124.6{\sim}260.0\;MPa$, and $14.8{\sim}29.4\;MPa$, respectively. The strength of MC and HPMC films was higher than that of low density polyethylene (LDPE) films $(13.1{\sim}27.6\;MPa)$. Solubility of the cellulose films varied widely by plasticizer used and the films containing polyethyleneglycol (PEG) as a plasticizer was more soluble than the films by glycerol. Maximum water vapor permeability and oxygen permeability of the cellulose films was more than 1,000 folds and less than one-twelfth of the LDPE film, respectively.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.3
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• pp.121-130
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• 2018

'Mats-kyeong-chae (Brassica lee ssp. namai cv. Tongssamchoo)', a new type of sweet Korean cabbage for fresh wrapping and soup cooking, was released by the Korea National College of Agriculture and Fisheries. The shelf-life and quality changes of this new cultivar was evaluated by packaging with PP (polypropylene) film bag and storing at three temperatures ($5^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$). As control, the cabbage was packaged in a corrugated paper box and stored at $25^{\circ}C$. At the storage temperature of $5^{\circ}C$, the degree of freshness, weight loss, hue angle and SPAD on cabbage packaged with PP film bag maintained its good quality and exhibited a longer period of marketable life compared to the samples stored in other treatments. Results showed that the use of PP film packaging and storing at $5^{\circ}C$ could be the optimum condition for commercial storage of 'Mats-kyeong-chae'. Further investigation on other quality parameters according to different packaging methods would be useful in maintaining the quality of 'Mats-kyeong-chae' at postharvest stages.

• Journal of Conservation Science
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• v.22
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• pp.5-14
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• 2008

The effect of air pollutants coming from internal museum materials such as wood-based products and cements on metal corrosion have been investigated. The Oddy test and the Chamber test was employed as a corrosion test. The metal pieces after the Oddy test had different corrosion types caused by the internal museum materials. The most effective wood based product was 18T HS(E0) and 9mm plywood(F0,E0). Iron(Fe) and copper(Cu) also bronze of the Chamber test had corrosion caused by Formic acid, Acetic acid, and Acetaldehyde. The packing materials in high humidity had caused more corrosion on the surface of the metal pieces than in low humidity.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.1 s.16
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• pp.77-84
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• 2005

Amount of demolished concretes is highly produced as dismantlement of structures to increased owing to usage alteration and deteriorated of concrete structures, but most of them have been used as material for simple reclamation. Therefore, if demolished concrete could be recycled as aggregate for concrete. it will contribute to solve the exhaustion of nature aggregate, in terms of saving resources and protecting environment, especially being want of resources in Korea. In this study it was investigated into experimental results that were carried out demolished concrete recycled aggregate gained from dismantled real structures and source concrete recycled aggregate produced according to respectively 5 steps of replacement ratio for recycling as pavement concrete aggregate.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.89-96
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• 2012

The Falling Weight Deflectormeter has been widely used in evaluating the structural adequacy of pavement structures. The deflections measured from the FWD are capable of estimating the stiffness of pavement layers and measuring the pavement responses in the pavement structure. The objective of paper is to develop the pavement response model using a partial least square regression technique based on the FWD deflection data. The partial least square regression method enables to solve the multicollinearity problem occurred in multiple regression model. It is also found that the pavement response model can be developed using the raw data when a partial least square regression was used.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.202-208
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• 2002

진공냉각장치의 효율적인 설계를 위하여 파일럿 규모의 진공냉각장치에서 진공압력에 따른 작물별 냉각특성과 운전조작에 따른 냉각특성을 구명하는 요인실험을 실시한 결과 가. 배추와 같이 조밀하게 결구되어 있는 작물은 프레시 포인트로부터 습구온도와 품온에 따라 진공압을 조절함으로서 표면과 심부의 온도편차를 줄일 수 있고 버섯, 상추와 같이 개체가 작은 작물은 진공압력에 따른 온도편차가 거의 나타나지 않았다. 나. 포장방법에 따른 냉각 특성에서는 무개공 및 개공율 5% 골판지상자, PE 상자, 6mm 통기공이 있는 필름 포장에서의 냉각속도는 유사한 경향을 나타냈으나 0.8mm의 통기공을 가지고있는 필름 포장에서는 냉각속도가 현저히 낮게 나타나 필름 포장을 했을 경우 최소 개공율의 구명이 필요한 것으로 나타났다. 다. 예냉전 농산물 표면에 가수를 했을 경우 배추와 같은 결구성 농산물은 감모율 저하에는 효과적이었으나 무가수에 비해 냉각균일도와 냉각속도가 낮게 나타났으며 버섯에서는 감모율 저하 및 냉각속도 향상에 효과가 있는 것으로 나타났다.