• Asian Journal of Turfgrass Science
• /
• v.25 no.2
• /
• pp.133-137
• /
• 2011

Winterkill can be defined as any injury including freeze stress kill, winter desiccation, and low temperature disease to turfgrass plants that occurs during the winter period. The major damages from winterkill were low temperature kill, crown hydration, and winter desiccation. Low temperature kill is caused by air and soil temperature. Soil temperature affect more severe to turfgrass than air temperature because low soil temperature cause fetal damage to turfgrass crown. Crown hydration is a form of winter injury in which intercellular water within the plant freezes and causes physical injury to the cell membrane and wall. This is eventually resulted in dehydration of cell. Winter desiccation is the death of leaves or whole plants due to drought during the winter period. To reduce winterkill damage, cultivar selection is very important. If changing cultivar is not allowed, cold temperature hardiness needs to be increased by providing nutrients especially phosphorus and potassium in the late fall. Turf cover is effective way to reduce winterkill damage. Remaining snow is positive process to reduce winterkill damage by insulating soil temperature. The previous researches reported many materials as turf cover such as straw, polypropylene, polyester, and wood mat. Aeration and topdressing is one of the process against winterkill. Both methods are mainly conducted to reduce thickness of thatch layer. In recent, relatively new materials called black or winter topdressing sand are used to protect soil temperature from low air temperature and thaw ice crystal that may remain in soil.

• 한국유가공학회:학술대회논문집
• /
• 2006.06a
• /
• pp.29-45
• /
• 2006

최근에 들어 웰빙(well-being)과 함께 로하스(LOHAS: Lifestyle of Health and Sustainability)란 개념이 급속도로 확산되고 있으며, 이를 만족하는 식품으로 친환경 농산물과 유기 가공 식품이 대두되고 있다. 여러 마케팅 조사에서도 친환경 농산물과 유기 가공 식품의 소비자 선호도는 상당히 높게 나타난다. 이러한 다양한 소비자의 요구에 맞춰 우리의 2세에게 더욱 안전하고 좋은 품질의 이유식을 제공하고 나아가 한계에 이른 '지구와 환경을 해치지 않는 지속가능 한 소비'를 유도하고자 업체들은 유기농 이유식을 개발하고 있다. 유기농 소비자 10명 가운데 7명은 최근의 웰빙 붐 때문에 유기농에 관심을 가지게 됐으며, 가격이 다소 비싸더라도 가족의 건강을 위해 친환경 농산물을 구입하는 것으로 나타났으며, 국내외를 막론하고 친환경 농산물과 유피 가공 식품의 시장 동향을 살펴보면 지속적으로 증가하고 있으나, 아직까지 일반 제품에 비해 미미한 수준이며, 국내는 인증 제도가 없으나, 유기 가공 식품표시기준에 따라 표시되고 있다. 일반적으로 이유식이라 함은 식품공전에서 영 ${\cdot}$ 유아용 곡류 조제식만을 말하지만 넓게 축산물의 조제유류, 영아용 조제식, 성장기용 조제식, 기타 영 ${\cdot}$ 유아식을 포함할 수 있으며, 유기농 이유식 제조 현황을 살펴보면 동결, 분무, 드럼 등의 건조와 퍼핑이나 Extruder를 통한 알파화로 원료를 가공하여 은 살균, 멸균, 균질, 혼합, 건조, 냉각, 포장 등의 다양한 공정으로 이루어진 분무건조나 유동층이나 연속식 과립기를 사용하여 분말이나 입자형 이유식을 생산하며, 동결 건조를 하여 열수를 가해 죽 상태로 먹을 수 있도록 한 제품, 데워서 떠 먹일 수 있도록 병조림이나 레토르트 유동식 제품, 바로 마실 수 있는 쥬스류, 두유류, 과자 등으로 생산하고 있다. 주된 메이저4사는 일동후디스, 남양유업, 매일유업, 파스퇴르유업으로 다양한 제품들을 생산하고 있으며, 두유를 위주로 한 정식품, 연세우유와 종근당건강, 다양한 다국적 기업들의 제품이 수입되고 있는 실정이다. 이유식 시장도 96년 하반기부터 정체를 보이는 상태다. 2002년도 이유식 시장은 약 1,300억원 규모로 업체들의 고가 신제품과 유기농 이유식 출시로 판매 금액은 소폭 상승하였으나 판매 수량은 큰 변동이 없다. 저출산에 따른 양육비 집중과 유기농 제품에 대한 저변이 크게 확산돼 베이비 웰빙은 어느 정도 예견된 일이거니와 이미 미국 등 선진국에선 유아에 그치지 않고 아동까지 유기농과 고급 원료를 사용한 고가의 웰빙 제품이 봇물을 이루고 있는 상황이어서 유아식 시장은 어느 때보다 경쟁이 치열할 것이며, 국내 식품 업체들이 너도나도 유기농 제품과 매장사업에 뛰어들고 있다. 유기 가공 식품의 지속적인 발전을 위해서 (1) 국내산/수입산 공통으로 인증 제도가 도입되고 원료 농산물뿐만 아니라, 모든 공정이나 공장에 대한 종합적 관리와 동일한 인증 표시가 이루어져야 한다. (2) 정부 부처의 이기를 타파할 수 있는 법정부적 기구나 대책이 필요하다. (3) 유기 가공 식품을 취급하는 업계에서는 기존 3%의 비의도적 혼입치의 고려나 상한선 재설정을 요구하고 진정한 유기 가공 식품으로 공정 경쟁한다. (4) 활발한 인증심사원의 교육과 배출로 인증이나 심사기관의 민간 이양을 적극 장려하고 국가관 상호 신뢰를 구축한다. (5) 각 소비자 단체나 소비자는 환경을 살리고 생명체의 공생이라는 관점에서 최선의 길이 유기농 제품임을 인식하고 소비하여 우리의 다음 세대에게서 빌려온 소중한 환경을 물려준다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.17 no.1
• /
• pp.29-36
• /
• 2019

High-level radioactive waste (HLW) such as spent fuel is inevitably produced when nuclear power plants are operated. A geological repository has been considered as one of the most adequate options for the disposal of HLW, and it will be constructed in host rock at a depth of 500~1,000 meters below ground level with the concept of an engineered barrier system (EBS) and a natural barrier system. The compacted bentonite buffer is one of the most important components of the EBS. As the compacted bentonite buffer is located between disposal canisters with spent fuel and the host rock, it can restrain the release of radionuclides and protect canisters from the inflow of groundwater. Because of inflow of groundwater into the compacted bentonite buffer, it is essential to investigate soil-water characteristic curves (SWCC) of the compacted bentonite buffer in order to evaluate the entire safety performance of the EBS. Therefore, this paper conducted laboratory experiments to analyze the SWCC for a Korean Ca-type compacted bentonite buffer considering dry density, confined or unconfined condition, and drying or wetting path. There was no significant difference of SWCC considering dry density under unconfined condition. Furthermore, it was found that there was higher water suction in unconfined condition that in confined condition, and higher water suction during drying path than during wetting path.

• 한국연소학회:학술대회논문집
• /
• 2014.11a
• /
• pp.29-32
• /
• 2014

The practical route for disposal of sewage sludge becomes energy recovery by combustion after its ocean dumping is banned in 2012 in Korea. Due to the high moisture content, however, sewage sludge is required to be dried before transport and combustion. In this study, pyrolysis and combustion characteristics of dried sewage sludge was investigated in a small-scale fixed bed reactor in order to provide fundamental data for energy recovery of the fuel. As the first step of combustion, the primary products of pyrolysis were analyzed in a fixed bed reactor for the condensable volatiles (tar), non-condensable gases, and char. For the combustion characteristics, another fixed bed reactor was constructed to monitor the weight and temperature of the fuel particles during ignition and combustion under different air flow rates. The test results were used to derive the ignition and burning rates.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.13 no.3
• /
• pp.168-182
• /
• 1984

For the purpose of drying high moisture rough rice effectively, from the view point of pre-drying, some basic experiments of fluidized bed drying of rough rice were carried out. The minimum fluidization velocities $(U_{mf})$ for both rough rice and glass bead were analyzed to find out fluidizing characteristics. The main results obtained were as follows ; 1) Minimum fluidization velocity of rough rice and glass bead were 2.01m/s and 4.07m/s, respectively, when using the distributor with $16\%$ opening ratio. 2) $U_{mf}$ calculated by Shirai's empirical equation and that calculated by Wen's modified equation were inconsistent with experimental data, while $U_{mf}$ calculated by Ergun's equation was consistent with the experimental data. 3) The following equations, on the basis of Leva's equation, were obtained. $$C_{mf}=1.19\times10^{-4}(Re_p)^{-0.0318)\;(rough rice)$$ $$C_{mf}=1.02imes10^{-4}(Re_p)^{-0.0047)\;(glass bead)$$

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.10a
• /
• pp.301-308
• /
• 1999

With the shortage of the land and NIMBY syndrome, it is issued recently that the capacity of waste-landfill site is needed though the decreasing tendency of waste landfill. From this point, the stability is the most essential problem in the landfill that will be constructed. Advanced design and construction are most important for that. In this paper, for the study of desiccation, dry-shrinkage crack from drying and chemical reaction in cement hydration, which is occurred when the surface layer stabilization method is applied in wast landfill, laboratory test of the ground and specimen according to the mixture ratio of stabilizer is performed. From the result, it is notified that the uni-axial strength increases with the stabilizer, but dry-shrinkage increases too, therefore, it is important and the goal of this study to find the optimal mixture ratio of each stabilizer. Analysis of variance for regression with acting variables is performed to find optimal mixture ratio of each stabilizer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.184-184
• /
• 2010

ITO의 전극 패턴에 따른 유기 광기전력 소자의 전기적 특성에 대해서 연구하였다. 소자의 구조는 ITO/PEDOT:PSS(90nm)/CuPc(20nm)/$C_{60}$(40nm)/LiF(0.5nm)/Al(100nm)이고, PEDOT:PSS는 스핀 코팅한 후 $120^{\circ}C$에서 20분간 건조시켰으며, 유기물은 열증착을 하여 제작하였다. ITO 전극의 패턴을 corss-bar type과 island type으로 하여 소자의 특성을 비교하였다. 광원은 500W xenon lamp를 사용하였고, optical density filter로 광원의 세기를 조절하였으며, AM 1.5G의 스펙트럼을 조사하였다. PEDOT:PSS 층을 사용함으로서 유기 광기전력 소자의 효율, 단락 전류, 그리고 개방 전압의 향상을 얻을 수 있었다. ITO 전극 패턴에 따른 광기전력 소자의 특성은 cross-bar type에 비하여 island type의 구조에서 유기 광기전력 소자의 효율이 34% 감소하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.602-605
• /
• 1999

We dried emitting layer of EL device at 30, 80, I20 and $150^{\circ}C$ for Ihr to investigate the effects to the emission characteristics of devices. PL intensity of P3HT thin film decreased with increasing the drying temperature. But, the EL intensity and stability of device with emitting layer dried at $150^{\circ}C$ were the best. We think it s because of absence of water and remaining solvent in P3HT emitting layer. So, We suggest that the drying temperature of emitting layer of EL device should be select slightly low temperature than its glass transition temperature.

• Journal of The Geomorphological Association of Korea
• /
• v.26 no.1
• /
• pp.107-119
• /
• 2019

In recent years, the drying of the water spider habitat has been progressing rapidly. This is the primary cause of extreme climatic events in 2014/2015 with overall reduction in annual precipitation, but impermeable clayey layer formed in the superficial formation also plays an important role. The clayey layer is a critical factor in the formation of wetlands on a well-drained lava plateau, but paradoxically, it restricts the connection with ground water, increasing the instability of the water balance and making it precipitation-dependent structure. In addition, construction of roads/drainways has also caused drying of wetlands by blocking or rapidly spilling surface water/sheet flow. Therefore, to keep the wetlands sustainable, it should increase the flow into the wetlands by removing the road/drainways and floodgates installed to reduce the outflow.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.3
• /
• pp.530-539
• /
• 2003

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Charisma, Filtek P 60, Palpique Estelite, and Spectrum. Preweighed discs of each brand were exposed to 0.1N NaOH solution at $60^{\circ}C$. After 2 weeks they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth(${\mu}m$) - measured SEM and CLSM from polished circular sections of exposed specimens. The results were as follows: 1. The sequence of mass loss was in descending order by Palpique Estelite, Filtek P 60, Charisma, and Spectrum. 2. The sequence of the degree of degradation layer depth was in descending order by Filtek P 60, Charisma, Palpique Estelita, and Spectrum. 3. The sequence of the Si loss was in descending order by Chrisma, Spectrum, Palpique Estelite, and Filtek P 60. 4. The correlation coefficient between mass loss and degradation layer depth was relatively high(r=0.704, p<0.05). 5. When observed with SEM, destruction of bonding was observed between resin matrix and filler. 6. When observed with CLSM, degradation layer depth of composite resin surface was observed.