In this study, an experimental analysis of noise reduction in road traffic by applying the Micro Grooving technique to concrete highway pavements is explored. Initiated in 1984 to address the aging and damage issues observed in South Korea's concrete highways, Micro Grooving is known for creating fine grooves on the cement pavement surface to increase friction, prevent hydroplaning, and inhibit ice formation, while reducing vehicle friction noise by 3∼5dB(A). It is determined from noise measurement results that the application of the Micro Grooving method can be expected to reduce roadside noise and enhance the safety of drivers' driving experience.

Internal combustion engine is the main source of environmental pollutants and therefore advanced technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, when the exhaust gas is released from the automotive muffler, exhaust noise has many bad influence on the surrounding environment. In order to reduce the exhaust noise, it is necessary that automotive muffler must be designed for best exhaust efficiency. The sound insulation room was installed for the analysis of an acoustics characteristics of the noise from automotive muffler, in this study. Exhaust gas noise, noise distribution characteristics, pressure and temperature of exhaust gas were investigated with the change of annulus temperature of air cooled annulus automotive muffler and cooled annulus automotive muffler. The following results were obtained with this study. From the frequency analysis of automotive muffler, high noise distribution was observed in the range 100~2000Hz. It means that the noise in this range has an dominate influence for the overall noise. Noise reduction of automotive muffler was affected by the temperature of annulus. It is caused the result that the high temperature and pressure of exhaust gas are changed lower by the drop of annulus temperature. The tendencies of noise, the temperature and pressure of exhaust gas are similar to the performance curve of engine. Exhaust gas pressure is determined by the r.p.m. of engine and affected by the cooling performance of automotive muffler.

Metal material production process machinery is becoming larger due to the development of industry. Since there are many overseas manufacturers of large machines used in industrial fields, there are limitations in investigating the manufacturer's noise prediction method and measurement method. A noise map was prepared to obtain information necessary for noise reduction and to effectively manage noise companies. It was modeled with the drawings provided to prepare the noise map and the results of the actual measurement of the site. In order to improve the noise environment of workers, there was a noise reduction effect when a soundproof wall was installed between the noise source and the worker's workplace.

The main noise of a large machine can be divided into the noise generated during the work process and the noise of the equipment used in the work. The main noise in the noisy area is the air propagation sound caused by the operation of the rotating body. This is not fixed, but changes depending on the situation at the time of measurement. Workplaces exposed to noise can harm workers' health and cause related industrial disasters, resulting in many complaints and social problems, and eventually lead to a lot of damage in terms of productivity. Large machines that need noise reduction the most are motors, pumps, fans, blowers, and compressors. To reduce noise, mechanical structure or material changes are most effective. In this study, the noise reduction method and noise management method of large machines were investigated. To measure noise, the same method as ISO 3744 in Europe and JISA 8305 in Japan was used as KS A ISO 3744, KS A ISO 3746, which is a method of measuring the acoustic power level of machinery.

Due to the development of the industry, the machinery of plant facilities becomes large and operates at high speed and high power. Workers at plant facility sites are exposed to high noise and impact noise, and the number of people with noise-induced hearing loss is increasing every year. Therefore, in order to minimize such damage, many efforts have been made to reduce the noise of large machines in production facilities. Measures, education, and recommendation of wearing hearing protectors are needed to protect the hearing of workers in high noise industries. In addition, it is urgent to reduce noise sources by blocking noise propagation paths, such as installing noise boxes and silencers, and installing facilities and equipment that generate less noise. It is necessary to repair the noise reduction device of the large machine of the plant or to study the noise reduction device when designing the plant.

Noise is unwanted sound and nerve jarring sound or mentally and physically harmful sound to the human body. In the 20th century, the aviation industry have been comprehensive industry of all areas and humanity have been globalized, the number of aircraft operated have been increased continuously. We confirmed that the actual measured noise data was consistent with the aircraft average noise data to calculate noise maps of INM version 7.0. and based on this, the actual flight scenarios and the noise map were created. For making the noise map, we assumed that the maximum number of flight is operated.

A powder in sheath rolling method was applied to the fabrication of a carbon nano tube (CNT) reinforced aluminum composite. A 6061 aluminum alloy tube with outer diameter of 31 mm and wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powder and CNTs with a volume content of 5% was filled in the tube by tap filling and then processed to an 85% reduction using multi-pass rolling after heating for 0.5 h at 400˚C. The specimen was then further processed at 400˚C by multi-pass hot rolling. The specimen was then annealed for 1 h at various temperatures that ranged from 100 to 500˚C. The relative density of the 5vol%CNT/Al composite fabricated using powder in sheath rolling increased with increasing of the rolling reduction, becoming about 97% after hot rolling under 96 % total reduction. The relative density of the composite hardly changed regardless of the increasing of the annealing temperature. The average hardness also had only slight dependence on the annealing temperature. However, the tensile strength of the composite containing the 6061 aluminum sheath decreased and the fracture elongation increased with increasing of the annealing temperature. It is concluded that the powder in sheath rolling method is an effective process for fabrication of CNT reinforced Al matrix composites.

Prior austenite grain size plays an important role in the production of high strength hot-rolled steel. This study investigated the effect of Ti and C contents on the precipitates and prior austenite grain size. Steel with no Ti solutes had prior austenite grain size of about 620 μm. The addition of Ti ~ 0.03 wt.% and 0.11 wt.% reduced the prior austenite grain size to 180 μm and 120 μm, respectively. The amount of Ti required to significantly decrease the prior austenite grain size was in the range of 0.03 wt.%. However, the amount of carbon required to significantly decrease the prior austenite grain size was not present from 0.04 wt.% to 0.12 wt.%. Oxides of Ti (Ti2O3) were observed as the Ti content increased to 0.03 wt.%. The specimen containing 0.11 wt.% of Ti exhibited the complex carbides of (Ti, Nb) C. The formation of Ti precipitates was critical to reduce the prior austenite grain size. Furthermore, the consistency of prior austenite grain size increased as the carbon and Ti contents increased. During the reheating process of hot-rolled steel, the most critical factor for controlling the prior austenite grain size seems to be the presence of Ti precipitates.

담배와 고추의 주요해충인 담배나방 [Helicoverpa assulta(Guenee)]의 미생물적 방제법을 개발하기 위하여, 아직 국내에서 보고되지 않은 담배나방 핵다각체병 바이러스 담배나방 사충으로 부터 분리하고, 바이러스의 전자현미경 관찰 및 바이러스 DNA의 제한효소 분석 등을 통한 생화학적 특성을 조사하였다. 담배나방 핵다각체병 바이러스의 다각체는 구형에 가까운 20면체로서 크기는 평균 약 1.0m 정도이고, 다수의 바이러스 입자가 다각체 단백질에 포매되어 있었다. 포매된 바이러스 입자는 한개의 봉상 nucleocapsid가 하나의 envelope 내에 매립된 형태의 SNPV(single embedded nuclear polyhedrosis virus)로, 형태는 전형적인 봉상으로서 그 크기는 약 였다. 또한 다각체 단백질의 SDS-PAGE 분석 결고, 분자량은 약 31 Kd이었으며, 담배나방 핵다각체병바이러스 DNA를 분리하여 EcoRI. HindIII 등 수종의 제한효소로 처리분석한 결과, 그 genome의 크기는 약 120Kb 정도였다. 본 핵다각체병바이러스는 담배나방 유충에만 병원성을 나타내 기주특이성을 보였다.

본 연구는 선진 유가 사상을 정치적 측면과 윤리적 측면에서 입체적으로 분석 함으로써 그것의 공사문제를 규명하는 데 목적이 있다. 먼저, 家와 國의 영역 문제로 설명할 수 있는 부분과 해명되지 않는 부분이 무엇인지 드러낸다. 다음 으로, 그 해명되지 않는 부분이 단순히 인간의 본성 문제로 설명되는지, 만약 해명되지 않는 부분이 있다면 그것이 무엇인지 확인한다. 마지막으로, 그 해명 되지 않는 부분이 도덕 감정과 공동선의 상호작용임을 밝힘으로써 선진 유교의 공사관을 그림을 그려낼 것이다. 유교가 감정윤리라는 점에서 이모티비즘과 어 떻게 다른지, 그리고 그 차별성을 통해 유교의 감정윤리가 어떻게 공공성을 획 득할 수 있는지 해명한다.

A concrete-filled arch rib causes to increase effectively sectional strength and resistance against buckling, and minimize stiffeners. Since a reduced beam theory includes the effect of variable section properties, it is suitable to structural analysis of new composite girder such as SB-Arch girder. Analysis results are verified by experimental method, and arch behaviors and/or arching effects are shown to be increased for SB-arch girder with 20m span.

In this study, an analysis model with circular arc on the plane is chosen as a representative section of the steel box girder. The steel box girder has thin-walled cross section. When working load is increased in the outer sector, the behavior of the negative reaction and overturning moment are shown up. Curved bridge has a central angle from about 4 to 26 degree. Negative reaction and overturning moment are analyzed according to increase of a central angle from 4 to 26 degree as well as shape factor.