• Title/Summary/Keyword: FROST

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A Study on the Development Lightweight Aggregate using Clink Ash for Reduction in Freezing Ground (지반의 동결저감 대책기술을 수립하기 위한 클링커애쉬 인공경량골재 개발에 관한 연구)

  • Moon, Jong-Wook
    • Fire Science and Engineering
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    • v.23 no.6
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    • pp.116-125
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    • 2009
  • This study is progressed function ratio, it's trued taste by an experiment to present data for human work light weight aggregate development that use clink ash progressed liquid limit, small success limit, wear loss in quantity, sand equivalent, sieve cutting examination. 80 : 20's match of function rain examination is 1.4, and that use rubble Goljae as ckink ash lightweight aggregate's capacity ratio increases by 1.0 increase of function rain many. Also, examination multiplied delicate flavor gradually according to increase of the mixing rate, and absorption coefficient increased. This is judged by phenomenon that appear by special quality upper clink ash of polystyrene bid and porosity's increase between lightweight aggregate. It is case that use aggregate of wear loss in quantity is 13.5 in sand equivalent and a wear loss in quantity experiment and although case that mix 20% increases by 14.4, this phenomenon by weak tissue of lightweight aggergate be judge. When it's as a these experiment, the statue prevention floor of a street improvement specifications is prescribing so that satisfy by sand equivalent 20, CBR 10. This is showed result that this satisfies in quality standard all in match experiment ago that see.

An Experimental Study on the Creep Behavior of Frozen Sand (동결 사질토의 크리프 거동에 관한 실험적 연구)

  • Chae, Deokho;Kim, Youngseok;Lee, Jangguen;Cho, Wanjei
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.2
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    • pp.27-36
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    • 2014
  • Due to the latitudinal location of Korea, the seasonally frozen ground has been focused on as research topics such as the frost heaving under the asphalt road rather than the permafrost ground. However, the recent construction of the second Korean Antarctic research station, the Jangbogo station and the participation on the development of the natural gas pipeline in Russia arouse the research interests on the behavior of the permafrost ground. At the design process of the geotechnical structures on the permafrost ground, the evaluation of the creep characteristics of the frozen soil is very crucial. Since the domestic specification on the frozen soil testing does not exist currently, it is necessary to evaluate the creep characteristics of frozen soils systematically with regard to the affecting factors. Therefore, the creep characteristics of the frozen specimens of dense Jumoonjin sand were evaluated under various loads at -5 and $-10^{\circ}C$. Based on the test results, as the load became close to the strength and the temperature became lower, the duration of the secondary creep became shorter and more distinct tertiary creep responses were observed.

Estimating on the Erosion and Retreat Rates of Sea-cliff Slope Using the Datum-point in Pado-ri, the Western Coast of Korea (침식기준목을 이용한 파도리 해식애 사면의 침식·후퇴율 산정)

  • JANG, Dong-Ho;PARK, Ji-Hoon
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.3
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    • pp.71-82
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    • 2012
  • This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

Postharvest Handling and Marketing Management for Making High Salability of Sweetpotatoes (상품성 제고를 위한 고구마 수확 후 관리 및 출하기술)

  • Jeong, Byeong-Choon
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2001.06a
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    • pp.51-64
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    • 2001
  • The qualities including taste of sweetpotato stored during the winter which can display in the spring market in Korea are affected by availability of storage for the roots. In order to make high storage availability of sweetpotato, the postharvest handlings should be done thoroughly from the moment of harvest until shipping them to the market. A lot of procedures that must be handled carefully for improving postharvest management are as follows; digging, trimming, gathering, putting in storage containers, carrying them from field to house, curing, storing, washing, drying, selecting marketable roots, packing and shipping to the market, etc.. Sweetpotatoes have a high moisture content, and a relatively thin and delicate skin, and are sensitive to chilling, so careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. From now on research has concentrated on the improvement of postharvest conditions to increase yield and lower disease rates. Storage, which makes sweetpotatoes available through out the year, benefits both the producer and the consumer. Seven very important points must be needed in order to get the best quality marketable roots in the storing of sweetpotatos : $\circled1$The storage house must be clean and sanitary, $\circled2$The crop must be harvested before the first frost to avoid low-temperature injury, $\circled3$Particular care must be taken to avoid cutting, bruising, or other injuries of the sweetpotatoes during digging, picking up, grading, placing in containers, and moving to the storage house, $\circled4$Select sound, disease-free roots for storage $\circled5$Sweetpotatoes should be stored in properly stacked containers $\circled6$Cure immediately after harvest, preferably at 32∼33$^{\circ}C$ and 90 to 95 percent relative humidity for 4 to 7 days, After curing the temperature should be reduced to 13$^{\circ}C$ to 16$^{\circ}C$ by ventilating the storage with outside air. $\circled7$Store at 12$^{\circ}C$ to 14$^{\circ}C$ and a relative humidity of 80 to 85 percent. Storage houses should be located on suitable sites and should be tightly constructed and insulated so that temperature and humidity will be uniform. Sweetpotatoes are usually not washed and graded, and lately sometimes washed, graded, waxed, before being shipped to market. Consumer packaging of sweetpotatoes in paper boxes(10-15kg) or film bags is done mainly to aid marketing. The shelf life of washed roots in consumer packs in only 1 to 2 weeks. Weight loss of roots during marketing is much less in perforated film bags than in mesh and paper bags. Perforation of 0.8 to 1kg polyethylene bags with about six 6mm holes is essential ; to lower the internal relative humidity and avoid excessive sprouting, rooting, and dampness. Development and use of better postharvest handling with good storage facilities or marketing methods can minimize sweetpotate losses and has an effect of indirectly increasing productivity and farmer’s income.

Hydrophobic property of surface glaze of ceramic tiles by copper powder addition (구리 분말 첨가를 통한 도자타일 표면유약의 소수화 특성)

  • Choi, Cheong-Soo;Han, Kyu-Sung;Hwang, Kwang-Taek;Kim, Jin-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.5
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    • pp.215-221
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    • 2019
  • Ceramic tiles, which are widely used as interior and exterior materials for construction, have recently been required to have pollution prevention function. In order to remove contaminants, many researches of ceramic tiles with hydrophilic surface property through $TiO_2$ coating and hydrophobic surface property by improving the flow of water droplets have been proceeded. Expecially, it is very important to develop a surface glaze having hydrophobicity through a sintering process above $1000^{\circ}C$ without an additional coating process and the degradation of mechanical properties. In this study, surface glaze with copper powder was applied to manufacture of ceramic tile. Contact angle of ceramic tile according to thickness of surface glaze layer was investigated after the conventional sintering process. The contact angle of the ceramic tile surface without the copper powder was shown to be $25.3^{\circ}$, which is close to hydrophilic surface. However, the contact angle was increased up to $109.8^{\circ}$ when the thickness of surface glaze with the copper powder was $150{\mu}m$. The excellent hydrophobic property of the surface glaze with copper powder was resulted from the cellular structure of copper particles on the glaze surface. In addition, the mechanical properties of the developed hydrophobic ceramic tiles such as bending strength, chemical resistance, abrasion resistance, and frost resistance were well maintained and meet the criteria of 'KS L 1001 Ceramic tile'.

Numerical Analysis for Improvement of Windshield Defrost Performance of Electric Vehicle (전기자동차 전면유리 제상성능 개선을 위한 전산수치 해석)

  • Kim, Hyun-Il;Kim, Jae-Sung;Kim, Myung-Il;Lee, Jae Yeol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.477-484
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    • 2019
  • As the residence time in the vehicle increases, the passenger desires a pleasant and stable riding environment in addition to the high driving performance of the vehicle. The windshield defrosting performance is one of the performance requirements that is essential for driver's safe driving. In order to improve the defrosting performance of the windshield of a vehicle, relevant elements such as the shape of the defrost nozzle should be appropriately designed. In this paper, CFD based numerical analysis is conducted to improve defrost performance of small electric vehicles. The defrost performance analysis was performed by changing the angle of the defrost nozzle and the guide vane that spray hot air to the windshield of the vehicle. Numerical simulation results show that the defrosting performance is best when the defrost nozzle angle is $70^{\circ}$ and the guide vane installation angle is $60^{\circ}$. Based on the analytical results, the defrosting experiment was performed by fabricating the defrost nozzle and the guide vane. As a result of the experiment, it is confirmed that the frost of windshield is removed by 80% within 20 minutes, and it is judged that the defrost performance satisfying the FVMSS 103 specification is secured.

Development of a Gangwon Province Forest Fire Prediction Model using Machine Learning and Sampling (머신러닝과 샘플링을 이용한 강원도 지역 산불발생예측모형 개발)

  • Chae, Kyoung-jae;Lee, Yu-Ri;cho, yong-ju;Park, Ji-Hyun
    • The Journal of Bigdata
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    • v.3 no.2
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    • pp.71-78
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    • 2018
  • The study is based on machine learning techniques to increase the accuracy of the forest fire predictive model. It used 14 years of data from 2003 to 2016 in Gang-won-do where forest fire were the most frequent. To reduce weather data errors, Gang-won-do was divided into nine areas and weather data from each region was used. However, dividing the forest fire forecast model into nine zones would make a large difference between the date of occurrence and the date of not occurring. Imbalance issues can degrade model performance. To address this, several sampling methods were applied. To increase the accuracy of the model, five indices in the Canadian Frost Fire Weather Index (FWI) were used as derived variable. The modeling method used statistical methods for logistic regression and machine learning methods for random forest and xgboost. The selection criteria for each zone's final model were set in consideration of accuracy, sensitivity and specificity, and the prediction of the nine zones resulted in 80 of the 104 fires that occurred, and 7426 of the 9758 non-fires. Overall accuracy was 76.1%.

The Character Figuration of Yeoheon Jang Hyungwang in the folk tales (설화에 나타난 여헌(旅軒) 장현광(張顯光)의 인물 형상)

  • Jang, Jeongsoo
    • (The)Study of the Eastern Classic
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    • no.57
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    • pp.41-66
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    • 2014
  • The Purpose of this paper is, through the character-figuration aspect of existing Yeoheon Jang Hyungwang(旅軒 張顯光, 1554~1637)-related folk tales, to determine the relation between the people's awareness on Yeoheon and the change in the folk tales. Only 4 pieces of Yeoheon-related folk tales are existed ; ; Forgiving a rude son of the provincial governor generously. ; Predicting 'the frost of May' and Preventing the cold-weather damage, when he served as Euiseong governor, and ; The folk tales of origins of the place name - Chimabawi Rockand Yeoheondae. shows the great scholar's liberal-hearted and generous personality. One day Jang Hyungwang looked shabby and a young person was quite rude to him. But Jang Hyungwang forgive him generously. Also Yeoheon teach him the thrift and modesty. described him as a governor filled with a love for the people. He tried to edify the people with the Confucian ethics and improve the life's work of the people. embodied him as a government official of high integrity. When his wife received the silk slip from the people, as farewell gift, he ordered his wife return that. and show the images of the Predicting the future and an extraordinary moralizer. Generally These folk tales are based on his personality, whereabouts and the real case. So we could find his images in the folk tales are close to his actual feature - thrift, modest, noble-minded, well-versed in Iching and practicing moral statesmanship.

PCR-based markers to select plastid genotypes of Solanum acaule (Solanum acaule 색소체 유전자형 선발을 위한 특이적 분자마커 개발)

  • Park, Tae-Ho
    • Journal of Plant Biotechnology
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    • v.49 no.3
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    • pp.178-186
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    • 2022
  • The tetraploid Solanum acaule is a wild potato species from Bolivia widely used for potato breeding because of its diverse attractive traits, including resistance to frost, late blight, potato virus X, potato virus Y, potato leafroll virus, potato spindle tuber viroid, and cyst nematode. However, the introgression of useful traits into cultivated potatoes via crossing has been limited by differences in endosperm balance number between species. Somatic fusion could be used to overcome sexual reproduction barriers and the development of molecular markers is essential to select proper fusion products. The chloroplast genome of S. acaule was sequenced using next-generation sequencing technology and specific markers for S. acaule were developed by comparing the obtained sequence with those of seven other Solanum species. The total length of the chloroplast genome is 155,570 bp, and 158 genes were annotated. Structure and gene content were very similar to other Solanum species and maximum likelihood phylogenetic analysis with 12 other species belonging to the Solanaceae family revealed that S. acaule is very closely related to other Solanum species. Sequence alignment with the chloroplast genome of seven other Solanum species revealed four InDels and 79 SNPs specific to S. acaule. Based on these InDel and SNP regions, one SCAR marker and one CAPS marker were developed to discriminate S. acaule from other Solanum species. These results will aid in exploring evolutionary aspects of Solanum species and accelerating potato breeding using S. acaule.

A Study on the Application of Design Process in the Architectural Design Practice (건축설계 실무과정에서 디자인 프로세스의 적용에 관한 연구)

  • Kang, Mi-hyun;Kim, So-ra;Shin, Byeong-uk
    • Journal of the Korean Institute of Rural Architecture
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    • v.24 no.3
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    • pp.59-66
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    • 2022
  • This study aims to find out how architectural designers applied the design process and what content is applied in the practical process of architectural design in Korea, and to improve it if there is a problem. So the study is carried out by investigating 13 architects(Including one person who wants to keep his work private) with extensive experience in architectural design. The architects were questioned on how and what content the design process was used for their representative works that had been designed. And interviews and field surveys were conducted on other matters to be improved. The survey was conducted from November 2021 to July 2022. According to the conclusion of this study, First, Most architects were applying the design process in the architectural design practice. These are caused by an impact on education, but there was also an aspect of preparation in terms of guidelines such as the Architects Association and storage rights. Second, Although the design process differed in each name and phase, it was generally carried out in the order of the start phase, the planning work phase, the basic design phase, the intermediate design phase, the implementation quarterly, and construction. Third, The step-by-step work of the design process differed slightly depending on the architect, but counseling and contract work were mainly performed at the start-up phase, and field surveys, legal investigations, and case studys were conducted at the planning phase. In the basic design phase, some contents related to architectural programming, basic drawings, images, and models were used as main work contents. In the intermediate design phase, secondary contents such as licensed books and facility facilities were the main tasks. In the implementation design phase, detailed maps and various frost facilities were finally inspected. Since then, construction and supervision have been carried out in the order of progress. Forth, As for the contents to be improved in the future, the architect's ability, the designer's knowledge of the overall architecture, the design supervision system, and the expansion of time for the initial design process were answered.