Roller Compacted Concrete Pavement (RCCP) is placed by roller compaction of a mixture of less cement and unit water content and more aggregates and provides excellent early strength development with the help of interlocking of aggregates and hydration. The unit cement content of RCC pavements accounts for 85% of conventional pavements, with low drying shrinkage. As low drying shrinkage leads to smaller crack widths than ordinary concrete, RCC pavements can help elevate reflecting crack resistance if applied to a base layer of a composite pavement system. In a composite pavement with an asphalt surface laid over a concrete base, pavement temperature change is important in predicting pavement performance. As movement of the lower concrete layer is determined by temperature depending on pavement depth, temperature data of the pavement structure serves as an important parameter to prevent and control reflecting crack. Among the causes of reflecting crack, horizontal behavior of the lower concrete layer and curling-caused vertical behavior of joints/cracks are considered closely related to temperature change characteristics of the lower concrete course (Baek, 2010). Previous studies at home and abroad about reflecting crack have focused on pavement behavior depending on daily and yearly in-service temperature changes of a composite pavement (Manuel, 2005). Until now, however, studies have not been conducted on initial temperature characteristics of concrete in composite pavements where asphalt surface is placed over an RCC base. Annual temperature changes of in-service concrete pavements go up to 60 ℃, and those of asphalt overlays become around the twice at 110 ℃. This study evaluated initial crack behavior of composite pavement by investigating pavement temperature by depth of an RCC base and analyzing joint movement depending on change to temperatures of continuously jointed pavements. Findings from the study suggest that in composite pavements and asphalt overlays, time of laying asphalt has an important impact on crack behavior and reflecting crack.

In recent years, pavement distresses have been caused by diverse factors such as spalling, deterioration of repaired sections, blow-up, and alkali aggregate reaction due to changing climate environment of a concrete pavement and its construction and maintenance conditions (supply of materials, increase in use of de-icers, etc,). As a leading repair method for deteriorated concrete pavements, partial-depth repair is implemented in accordance with guidelines of material properties for joints of a concrete pavement and field application evaluation systems, but still some of the repaired sections become deteriorated again at an early stage due to poor construction quality and failure of response to environmental impacts. Distresses that can be corrected with partial-depth repairs are largely divided into those of repair materials and of the existing pavement bonded to repair materials, and combined distress of repair materials and the existing pavement. Although re-repair methods should be different by distress type and scale than conventional pavement repair methods, appropriate repair methods and guidance for re-repairs have not been in place so far, and therefore currently, re-repair practices follow the existing manual of partial depth repairs. Therefore, this study evaluated concrete bond characteristics by removing method and repair scope for an experimental section of frequently distressed pavements to determine a re-repair scope and method for deteriorated partial depth repair sections of concrete pavement, the number of which has increased over time.

The composition of the deicer sprayed on the highway is spreading over the highway by the scattering or snow removal activity, or car movement and consequently affecting the vegetation environment around the highway. These are the cause of the damage of fruit trees and crops, and also the cause of corrosion of highway structures. The goal of this study is to estimate the detected range of deicer components from a highway. The concentration of the deicer components in gauze and soil were investigated according to the crossing distance from the highway. The data collected were then used to estimate the concentration range of deicer components in a rage of distance up to 100 m from the highway where the deicer was spread. The sample time and weight of gauze were measured before and after installation, and the soil was collected at more than three points in parallel with the highway at the gauze installation point. The components in gauze and soil were investigated in addition to the deicer components (Ca2+, Na+, Cl-) as well as Mg2+ and K+. As Ca2+ and Cl- components of deicer were affected by agricultural use, Na+ component was selected as a tracer and further SAR (Sodium Adsorption Ratio) of soil was analyzed to examine the degree of influence on vegetation indirectly. The gauze concentration was evaluated by the concentration of the deicer ingredient at the background concentration of the blank gauze. The total amount of the deicer sprayed in the study road for 4 months (winter season) was about 93 ton/km. In the gauze test, the spread of the deicer was detected at a distance of 100 m in study area, but the concentration of the deicer in the gauze by distance decreased rapidly within 10 m from the highway. And concentration of the deicer components in gauze and soil came down after rainy season (August ~ Sep.). The results showed that the components of the deicer could be spread widely by the wind. The effective range of the deicer on vegetation based on SAR in soil was estimated to be less than 20 m from the highway. This study examines the concentration changes of the deicer components in gauze and soils and shows that deicer components sprayed on the highway are accumulated and moved over time by wind, snow removal, terrain, water system and land use around the highway.

It is well known fact that the filed asphalt mixture is aged in the truck while hauling and queuing for one to four hours before dumping to the hopper of the paver. This aging, which is called short-term aging (STA), affect the physical and mechanical properties of asphalt mixture. For example, the maximum theoretical density of mixture is changed before and after STA. Therefore, when the asphalt mixture specimen is prepared for testing various physical and mechanical properties in laboratory, the mixture should be STA conditioned by a most-likely STA condition of the field. This is the reason why the STA should be performed properly. This study initiated to investigate STA conditioning protocols, set forth many agencies in the world, and to suggest a proper STA protocol which simulates field HMA condition as most likely as possible. According to this study, it was suggested that the blended loose mix for one specimen poured in a canister should be kept in a drying oven (no forced draft) without cap at 163±2℃ and for 70±15 min for normal HMA mix. This protocol was suggested based on that the absolute viscosity level of the recovered binder after STA should be a similar level of the same binder after a standard RTFO run.

최근 봄철 기온이 높아짐에 따라 마늘 뿌리응애 피해가 늘어나고 있는 실정이다. 이러한 뿌리응애 피해를 최소하 하고자 발생양상과 22종의 약제에 대하여 살비효과를 조사하였다. 마늘 재배시기 중 뿌리응애의 발생은 충북 보은 등 5지역에서 2015년부터 2017년까지 3년간 3월부터 6월까지 뿌리응애 발생밀도를 조사하여 발생양상을 확인하였다. 뿌리응애는 2016년에 가장 많이 발생하였으며, 발생시기는 월동 후 3월 상순부터 발생하여 6월 중순경까지 지속적으로 밀도가 높아지는 양상을 나타내었다. 조사된 5지역 중 가장 높은 밀도로 조사된 보은지역은 6월 상순경 주당 13.3마리가 발생하였다. 뿌리응애에 대하여 우수한 살비효과를 나타낸 약제는 분무처리시 약제처리 10일 후에서 dimethoate, azocyclotin, abamectin, hexythiazox, cabosulfan, spirotetramat, benfuracarb가 90% 이상의 살비효과를 나타내었다

본 조사는 채집방법에 따른 곤충군집을 비교하기 위해 공검지 습지보호지역 내에서 쓸어잡기, 함정트랩, 버킷트랩 세 가지 방법을 이용하였다. 조사 시기는 5월 15~16일, 8월 3~4일, 11월 6~7일 총 3회 실시하였으며, 조사는 보호지역 중심부에서 실시하였다. 본 연구결과 세 방법으로 총 7목 51과 110속 120종 14,717개체가 채집되었다. 채집방법별로 쓸어잡기에서 4목 25과 36속 37종 331개체, 함정트랩에서 3목 12과 18속 19종 30개체, 버킷트랩에서 6목, 38과 76속, 84종, 14,121개체가 조사되었다. 군집 분석결과 다양도 지수는 쓸어잡기가 3.63으로 가장 높게 나타났으며 풍부도 지수는 버킷트랩이 8.69로 가장 높게 나타났다. 유사도 지수는 세 방법이 서로 0.2이하로 매우 낮았다.

Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in forest is considered as a serious forest pest in pine trees. In this study, we collected entomopathogenic fungi from soil and assessed their virulence against the adults of the inset using a spray method in laboratory condition. Two entomopathogeinc fungi isolates showed high virulence against the adults. In the concentration of 1.0 × 107conidia/ml, the mortality rate of the adults were 53% and 60%. In semi-field condition, one isolate showed a virulence of 60% against the adult. Consequently, we confirmed the possibility of the fungal isolates in controlling the beetles. In near the future, we will investigate several factors which is possibly related to the control of the forest insect pest using entomopathogenic fungi in field conditions, given the importance of fungal formulation and practical application methods.

The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest. Therefore, this study provides a screening method to select entomopathogenic fungi, having high virulence against H. longicornis. The virulence test was conducted by dipping method with a conidial suspension (1×107 conidia/ml). As a result, cadavers of H. longicornis infected with entomopathogenic fungi were obtained by this method. Based on this results, we selected several isolates having high virulence to H. longicornis. We suggest that, selected isolates in this study can be used for the control of H. longicornis.

Entomopathogenic fungi have been known as promising candidates for biological control of insect pests. Recently, researchers consider the fungal thermotolerance in formulations and field applications. In this study, we investigated the production of thermotolerant Isaria javanica and I.fumosorosea conidia through grain-based solid cultures and exposure to light stress. As results, of the ten grain substrates, Italian millet, rice, perilla seed and sesame, rice, sorghum produced highly thermotolerant conidia in the strains. The two strains were exposed to a light stress and a heat stress. And they showed enhanced thermal stability compared to control, when exposed to 45°C for 2 hours. This work suggests that heat-resistant entomopathogenic fungal conidia can be produced by grain-based solid cultures and exposure to light stress.

Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) is a serious insect pest of various crops in the world. The management of this pest mainly have relied on chemical agents. However, the overuse of chemical agents for long times causes insect resistance, and negative effects on environment. Therefore, alternative control methods, such as biological control, that are less harmful to the environment and have different mode of action are needed to control this pest. In this study, we isolated entomopathogenic fungi from Korean soil, and characterized them via morphological and molecular identifications and pathogenicity check against Tenebrio molitor larvae. The isolated fungi were subjected to virulence assay against T. Palmi with a conidial suspension of 1×107 conidia/ml in laboratory conditions. This entomopathogenic fungi library would be a good resource to select effective strains for the control of T. palmi in fields.

Entomopathogenic fungi play an important natural role in regulating their insect host populations, and their ecology was also associated with plant and soil. These microorganisms have been living by reacting to insect, plant and environmental factor. The advanced bioinformatics technology such as next-generation sequencing and RNA sequencing has revolutionized in understanding of entomopathogenic fungi. Recently studies provided a lot of information on evolutionary relationships and virulence-related characteristics. We are starting to know where these microorganisms from is, and how they live in nature. The bioinformatics technology will give us further our understanding of the natural roles of these fungi in nature.

수출 시 절화 장미의 재배 및 공선단계의 관행 기술을 개선하고자 수출 절화 장미 ‘Beast’와 ‘Cappucino’의 관행 관리 실태를 조사하였다. 일본으로 장미를 수출하는 파주시와 전주시의 재배농가 농가와 공선장 내 채화와 선별 시 사용하는 관리도구의 청결수준을 조사한 결과, 채화가위, 길이 선별 가위와 장갑과 선별대, 포장 시 사용하는 장갑과 선별대에서 300CFU･mL-1이상의 박테리아수가 검출되었다. 파주시 재배 농가 저온고 내 절화가 담긴 저장수는 2.8×105CFU･mL-1로 박테리아가 검출되었으며, Chrysal RVB clear intensive(Chrysal, Netherlands, 1%)를 사용하는 전주시 농가의 저장수에서는 4.7×105CFU･mL-1로 검출되었다. 파주시 공선장의 수출박스내 박테리아수는 후처리제(Al2O3, pH 4.5)를 사용함에도 불구하고 2.7ⅹ104CFU･mL-1이었다. 한편 파주시 재배농가에서 포장을 마친 국내 생산수출용 ‘Beast’와 ‘Beast’의 가공장미인 매직로즈의 절화보존제(Florallife-Clear200, Oasisfloral, Japan) 유무에 따른 절화수명 연장 효과를 알아보고자 실험한 결과, ‘Beast’의 경우 절화보존제 처리구의 절화수명은 TW에 비해 3일 절화수명을 연장시킬 수 있었다. 반면 매직로즈의 절화수명은 TW와 절화보존제처리 간 유의적 차이가 없었다. 이때 보존용액 내 박테리아수는 ‘Beast’의 경우 TW와 절화보존제 처리구에서 각각 8.1×104, 2.0×103CFU･mL-1이었으며, 매직로즈의 경우 9.9×104, 1.0×103CFU･mL-1이었다. ‘Cappuccino’를 이용하여 국내용 선별 단계(건식운송)와 수출단계(습식운송)를 마친 절화의 절화수명을 조사한 결과, 국내유통용의 절화수명은 8일인 반면 수출용은 12일로, 습식운송했던 수출용 절화가 건식운송한 국내유통용절화보다 4일 길었다. 이에 따른 절화수명종료 현상은 국내유통용처리에서는 꽃목굽음(bent neck)과 꽃잎 탈리 현상이 각각 50%로 나타났고, 수출용처리구에서는 꽃잎탈리는 72.7%, 꽃목굽음은 18.2%이 나타났으며, 국내유통용처리에서 나타나지 않았던 잿빛곰팡이병이 9.1%로 나타났다.

The purpose of this study was to examine the relationship of fatigue and stress in seafarers. Ninety healthy adults were recruited and cumulative fatigue, stress index and stress resistance of seafarers were measured using autonomic nervous system analysis device (SA-6000; Medicoa Co. Ltd. Korea). The stress index had a significant correlation with the degree of resistance (p<.01). Cumulative fatigue and the stress index had a strong positive correlation (r=.781) with the stress resistance, cumulative fatigue had a strong negative correlation (r=.782) (p<0.01). Furthermore, the stress index had a strong negative correlation with the degree of resistance (r=.924) (p<.01). The present study indicate that there are significant correlation between the cumulative fatigue and stress index, cumulative fatigue and stress resistance, as well as stress index and stress resistance in the seafarers (p<.01).