생활권 수목이란 주민들이 생활하는 지역에 식재된 수목으로, 가로수, 학교수목, 아파트 수목 등 종류가 다양 하며 도시경관과 생활환경 개선의 이점을 제공한다. 그러므로 생활권 수목의 유지와 관리에 있어서도 인근 주민 에 혐오감이나 피해가 없도록 방제를 수행하는 것이 매우 중요하다. 일반적인 경엽살포의 경우, 약액 비산에 의해 주민들의 활동 제한, 안전사고 및 재산상 피해가 발생할 수 있으므로 사용이 제한적이다. 이러한 문제를 해결하기 위해, 나무에 약제를 직접 주입하는 나무주사(trunk injection)가 보편적인 생활권 수목 방제법으로 주목 받고 있으며, 이는 주입물질의 손실이 없고, 외부환경에 크게 영향 받지 않는다는 장점이 있다. 하지만 생활권 수목 전반에 대한 나무주사 처리방법이 명확하지 않아 약효가 일부 가지에서만 나타나는 등 사후 검증 및 관리가 미흡한 실정이다. 본 연구는 생활권 수목 병해충 방제 나무주사 제품의 효과제고를 위한 기존 처리방법 개선 및 최적의 약제처리 방법을 검증하였다. 느티나무외줄면충(Colopha moriokaensis)을 대상으로 시험을 진행하였 으며, Acetamiprid을 시험약제로 사용하였다. 느티나무에 대하여 약제처리 위치, 주입량, 천공수, 주사시기에 따른 약효 및 약해를 확인하였으며, 이를 바탕으로 최적의 약제처리 방법을 제시하였다.

The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.

PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.

The microstructure, phase, and mechanical properties of three aged porcelain insulators which were manufactured in different years (1973, 1995 and 2008) and which were used in the field for different amounts of time, were investigated. With X-ray 3D computed tomography (CT), defects with ~mm size can be detected without destroying the aged insulators. Defects of small specimens, which are cut from the aged insulators and polished, are analyzed with optical and scanning electron microscopy (OM and SEM), and defects of um size are detected by OM and SEM. The number and size of defects in all the aged insulators are similar. Porcelain insulators manufactured in 1973 contain more SiO2 (quartz and cristobalite) than those manufactured in 2008. Those manufactured in 2008 contain more Al2O3 than those manufactured earlier. The Vickers hardness of the insulator manufactured in 1973 has the lowest value. The formation of the cristobalite (SiO2) in the insulator manufactured in 1973 which can come from the phase transformation of quartz can cause stress in the insulator by formation of microcracks, which can lead to the low hardness of the insulator.