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.

The noise of large and high-power machines was evaluated and the establishment of mitigation measures was studied. The noise level of large machinery and high-power machinery installed at domestic plant sites was investigated and compared with the noise disclosure regulations to see if they met the standards of the Occupational Safety and Health Act. This investigated the soundproofing design of large and high-power machines and the soundproofing design of complex noise of large machines installed in the plant, and prepared the design standards of the plant design company. In the future, we will compile a database of data to secure standards for research and plant design related to noise reduction, and propose noise improvement and management measures for large and high-power machines.

The tribological properties of TiC, TiN and TiC/TiN coatings on steels prepared by the cathodic-arc (CA) ion plating technique were investigated. Experiments were carried out on a tribo-test machine using a Falex journal V block system. The friction and wear characteristics of the coatings were determined by varying the applied load and sliding speed. The TiC, TiN and TiC/TiN coatings markedly increased the tribological characteristics of the surface. As far as a single layer coating was concerned, TiN goes better results than TiC. However, the TiC/TiN multilayer coating performed better than either single layer coating. The major factor in the improved performance of the multilayer coating was the role of TiC in improving the adhesion between the external TiN layer and the substrate steel.

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.

Most domestic pilots are trained at local airfields using propeller aircraft. Training aircraft are mainly trained in the airspace around the aerodrome, and mainly take-off and landing exercises that require a lot of practice among flight control skills. Aircraft noise is a sound that humans do not want. In this study, based on the Rotax 914 engine used in Korea, the propeller blade angle was changed by 1 degree for the 3-leaf “K company” propeller and the 3-leaf GSC wooden propeller, and the engine RPM was changed to examine the noise and thrust changes. The purpose of this study is to check whether noise and thrust loss are the least at the engine's maximum RPM, and to propose an aircraft operation plan in the noisy aerodrome area based on the values.

A theoretical model has been studied to describe the sound radiation analysis for a railway under the action of harmonic moving line point forces. When a railway is analyzed, it had been modeled as curved beams with distributed springs and dash-pots that represent the radial, tangential stiffness and damping of rail, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force(T), damping coefficient(C) and stiffness of foundation(κ2) will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number(M), wave-number ratio(γ) and stiffness factor(ψ).

Noise is a sound that humans do not want. In this study, noise is measured for C172, the most frequently used general aviation trainer in Korea and abroad. In addition, in this study, noise measurement points are selected for Muan Airport, where most of the domestic training aircraft fly under the supervision of the Ministry of Land, Infrastructure and Transport. Based on this, the measured data is scaled and analyzed. In addition, we intend to analyze what characteristics C172 aircraft have unique through frequency analysis of noise of C172. Through this, it is intended to understand what type of noise training aircraft affect in future studies.

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.

Various kinds of friction materials were manufactured by adding 10%, 20%, and 30% of reduced iron, respectively, which has been obtained during the reduction process of blast furnace sludge extracted from the blast furnace, and its iron oxide, instead of existing barium sulfate(BaSO4) among the components of automobile brake friction materials. Fundamental physical property test and friction performance test, etc., using a brake dynamometer were carried out against these friction materials. Furthermore, when the expensive filling material, BaSO4 was substituted by reduced iron and added to the friction material, the added content of reduced iron for an excellent friction characteristic considering the heat emission temperature, wear, etc., was 10%. In the fundamental physical property test, as the added content of blast furnace sludge or reduced iron increased, and as the content increased, the shear strength and bonding strength of friction materials decreased, but both of them indicated sufficient strengths to be applied to a friction material. Even in the frictional performance test using a brake dynamometer, as the added content of blast furnace sludge or reduced iron increased, the friction coefficient reacted insensibly to brake deceleration, and its stability was improved.

The styling of automobile wheels and their effect on vehicle appearance has increased in importance in recent years. The wheel designer has been given the task of insuring that a wheel design meets its engineering objectives without affecting the styling theme. The wheel and tire system is considered as a vehicle component whose dynamic modal information of the tire/wheel system are employed in the modal synthesis model of the vehicle. The Modal characteristics of a Automobile wheel play an important role to judge a ride comfortability and quality for a Automobile. In this paper, the modal characteristics of a Al-alloy and steel wheel for Automobile are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function method. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.

가시광선 영역의 스펙트럼과 근적외선 영역의 스펙트럼을 포함하는 다중스펙트럼 기반 정밀 감지 기술은 농작물 품질, 스트레스 및 식물 병 진단 등의 비침습적 분석 및 감지에 성공적으로 적용되고 있고 원격 감지를 위한 센서 기술로 인정받고 있다. 다중스펙트럼 기반 원격 감지는 다양한 작물에서 다양한 병을 감지, 모니터링 및 정량화하는 데 사용되어 왔다. 본 연구의 목적은 양파노균병 감염의 지표로 엽록소 함량 관련된 다중스펙트럼 기반 식생 지수(Vegetation Index) 지표의 사용을 평가하는 것이다. 양파노균병은 주로 2~3월에 발생하고 양파 생산에 가장 큰 손실을 야기하는 양파병 중 하나다. 2021년 3월 중순경 공간적으로 분리된 경상남도 함양과 전라남도 무안 지역에서 노균병이 심하게 걸린 양파 노지 포장을 시험구로 사용하였다. 다중스펙트럼 카메라가 장착된 드론을 사용하여 다중스펙트럼 이미지를 얻었고 농작물 식생 지수 분석에 주로 사용되는 NDVI, NDRE 및 GNDVI 값을 분석하였다. 지상 20 m에서 얻은 다중스펙트럼의 NDVI, NDRE 및 GNDVI 수치의 히스토그램은 0 에 집중되어 있었는데 이는 주로 흙과 암석에서 나타나는 수치에 해당한다. 이는 양파 재배 특성상 물 빠짐을 좋게 하기 위해 조성한 고랑들이 식생 지수 수치를 왜곡한 것을 판단되었다. 양파가 없는 고랑으로 인한 식생 지수 왜곡을 배제하기 위해 지상 2 m에서 다중스펙트럼 이미지를 얻었고 이들의 식생 지수를 분석한 결과, NDVI 수치가 건전 양파와 노균병 감염 양파 간 차이를 뚜렷하게 구분할 수 있었다. GNDV 및 NDRE 값은 완전히 성장한 식물에서 높은 엽록소 민감도를 통해 식물 발달을 분석하기 위한 NDVI에 대한 경쟁적 식생 지수인데, 2~3월경 양파의 불완전한 생육으로 인해 캐노피가 부족하여 GNDVI와 NDRE의 민감도가 떨어진 것으로 추정된다. 노균병에 걸린 양파의 NDVI 수치는 0 값에 집중되어 있는 반면, 건전한 양파는 0.5 값에 걸쳐 있었는데, 이러한 결과는 생육환경이 전혀 다르고 지역적으로 분리된 함양과 무안 지역에서 재배되고 자연적으로 발생한 양파에서도 동일한 결과를 도출하였다. 본 연구의 결과를 종합하며, NDVI는 양파노균병 발생 감지에 적용할 수 있는 것으로 평가되고 뿐만 아니라 전문가 진단에 따른 변동성과 반복성의 변화를 극복할 수 있는 대안이 될 수 있을 것으로 평가된다.

Road surfaces and tires have a great influence on road noise in automobiles. Therefore, this study attempted to investigate the effect of changes in road surface and tire tread on road noise. For six road surfaces, road noise was measured and analyzed while changing two types of tire treads. In all frequency bands, the sound pressure of the road surface with a relatively large roughness was higher than that of other roads. And in the case of a road surface with relatively large pore, it was investigated that noise was reduced compared to other road surfaces due to the sound absorption effect in the low frequency area. On roads with irregular road roughness, the high sound pressure was exhibited in all frequency bands regardless of tire tread, indicating an increase in road noise due to irregular wear on roads. It was confirmed that the noise deviation due to the change in road surface was larger than the noise deviation due to the tire structure, and it is judged that noise research according to the structure and condition of the road surface.

Stone cutting process that it became with the tree, after fixing with the neck which is was fixed the stone in portable type transfer and department with cutting department which is in the process of operating and it transferred it was in the process of moving with the method which cuts with hour vibration where the stone will reach to the saw blade it was caused by, the raw materials waste and the inferior good which under the actual conditions which are disconnected from the default location of the stone are caused by soaking pit of the stone were under occurring. Consequently objective of this research currently the fixation stone cutter which is used from the stone processing and cutting enterprise about lower the productivity falls on a large scale with fixation, the raw materials loss to be many is sufficient the satisfactory degree of the enterprise considerably and to be insufficient in order the problem which is like this to solve the new cutting technical develop.

Assessment of noise exposed population is to check the environment noise level and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise abatement policy and action plan by accurately finding the area that the noise causes harmful effect to human health. Recently, a noise map, which can predict noise in comprehensive area, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for noise can be considered more effectively by using assessment methods of noise exposed population for specific noise level, area and building types which are the main input factors in noise maps. In this study, we propose noise prediction at traffic noise due to noise map.

최근 기후변화 및 국제교역량, 여행객, 외국 이주민 등의 증가로 국내 농작물에 큰 피해를 입힐 수 있는 고위험 식물 병의 국내 유입이 꾸준히 증가하고 있고 이에 따라, 검역기관 종사자들의 업무량도 늘어나고 있다. 특히 ‘Candidatus Liberibacter solanacearum’가 원인병원균인 감자 제브라칩병의 경우, 발생하게 되면 감자를 초토화시켜 막대한 피해를 야기한다. ‘Ca. L. solanacearum’의 감자와 토마토 등의 가지과(Solanaceae) 작물과 당근을 포함하는 산형과(Umbelliferae) 작물이 기주가 될 수 있다. 이에 본 연구에서는 아직까지 국내에 유입되지 않은 감자 제브라칩병과 매개충인 토마토 감자 나무이(tomato potato psyllid; TPP; Bactericera cockerelli Sulc.)에 대한 예찰 조사를 수행하였다. 예찰 조사를 위해 전국을 7개 권역(경기-강원, 충청, 전북, 전남, 경북, 경남 및 제주)으로 나누고, 각 권역에 속하는 3개 지역 중심으로 수행하였는데, 경기-강원 권역은 인천, 화성, 춘천 및 홍천, 충청 권역은 공주, 세종 및 청주, 전북 권역은 익산, 완주 및 정읍, 전남 권역은 보성, 고흥 및 순천, 경북 권역은 상주, 김천 및 안동, 경남 권역은 거창, 함양 및 진주, 제주 권역은 구좌 및 성산 지역이 해당되며, 지역당 3개 지점을 두고 조사하였다. 매개충 TPP 조사를 위해 끈끈이 트랩을 이용한 조사를 병행하였다. 예찰 조사는 2018년 9월부터 10월까지 2주 간격으로 실시하였다. 2018년 예찰 조사결과, 감자 제브라칩병과 매개충인 TPP는 국내에는 확인되지 않았다. 이 연구는 식물병을 조기에 탐지하기 위해 구축된 전국적인 모니터링 네트워크를 통해 수행할 수 있었고, 국외 외래유입병들의 예찰 조사를 위한 지역 거점을 확보하는데 기여하였다고 평가된다.

최근 기후변화와 더불어 국제 교역량, 여행객 및 외국 이주민 등의 증가로 인해 국내 농작물에 큰 피해를 입힐 수 있는 고위험 식물 병의 유입 사례가 꾸준히 증가하고 있는 추세다. 특히, ‘Candidatus Liberibacter asiaticus’가 원인병원균인 감귤황룡병의 경우, 발생하게 되면 감귤과원에 큰 피해를 야기한다. 이에 본 연구에서는 아직까지 국내 유입되지 않은 감귤황룡병과 매개충인 아시아감귤나무이(Asian citrus psyllid; ACP; Diaphotima citri)에 대한 예찰 조사를 남부지역에 집중된 유자 재배지 중심으로 수행하였다. 유자는 감귤황룡병의 기주가 될 수 있는 운향과(Rutaceae)에 속하는 작물로 기후 특성상 우리 나라 전라남도와 경상남도 해안지역을 중심으로 주로 재배되고 있다. 예찰 조사는 전남과 경남에 속하는 각 3개 지역 중심으로 수행하였는데, 전남 권역은 고흥, 보성 및 광양 중심으로 그리고 경남 권역은 거제, 통영 및 남해 지역이며, 지역당 3개 지점을 두고 조사하였다. ACP 포획을 위해 끈끈이 트랩을 이용한 조사를 병행하였다. 예찰 조사는 2018년부터 2020년까지 3년에 걸쳐 수행하였고 2018년은 6월부터 10월까지, 2019년과 2020년은 4월부터 10월까지 2주 간격으로 실시하였다. 예찰 조사 결과 감귤황룡병과 매개충 ACP는 국내에서는 아직 확인되지 않았다. 이 연구는 식물병을 조기에 탐지하기 위해 구축된 전국적인 모니터링 네트워크를 통해 수행할 수 있었고, 국외 고위험 식물 병들의 예찰 조사를 위한 지역 거점을 확보하는데 기여하였다고 평가된다.

Aircraft noise loss in residential areas around small heliports is becoming more and more serious. Under the condition of long-term exposure to aircraft noise, it will not only cause physical and mental harm to human body, but also cause social and economic losses to the living environment around the airport. Therefore, it has been a serious contradiction factor in the community for a long time. This study points out the impact of noise caused by helicopter flying in aviation brigade of small heliport on the nearby residence area, The fixed noise monitoring system is set up to measure the aircraft noise every day. and selects the measurement site to facilitate the impact of noise caused by helicopter flight on the surrounding life.

The area around a certain airbase was affected by the noise of military helicopters, which seriously reduced the quality of the living environment in the surrounding area. In this paper, an automatic noise measurement system is set at 3 measurement points around the flight path of the 00 flight field. The fixed noise monitoring system is set up to measure the aircraft noise every day。 and selects the measurement site to facilitate the impact of noise caused by helicopter flight on the surrounding life. There is also a manual noise level measurement of the helicopter's maximum noise level for 7 days at 3 locations. Calculate the WECPNL value of 3 measuring points. Analyze the correlation between the aircraft noise evaluation unit WECPNL-Lden.

최근 기후변화 및 국제교역량, 여행객, 외국 이주민 증가 등으로 국내 농작물에 큰 피해를 입힐 수 있는 고위험 식물병의 유입이 꾸준히 증가하고 있다. 검역 대상인 병원체의 수가 증가함에 따라 검역기관 및 연구원의 업무량이 증가하고 있다. 본 연구에서는 지역별 주요 수출대상 과수인 포도, 단감, 감귤의 국내 미기록 병과 원인병원체에 대한 예찰조사를 수행하였다. 이를 위해 전국을 경기-강원, 충청, 전북, 전남, 경북, 경남 그리고 제주 등 7개 권역으로 나누고 각 권역 소재 대학에서 예찰조사를 수행하여 예찰네트워크를 구축하고자 하였다. 포도 대상 병은 모두 4종으로, Pierce’s disease (Xylella fastidiosa), brown rot (Monilinia fructigena), anthracnose (Greeneria uvicola), 그리고 esca (Phaeomoniella chlamydospora)을 조사하였고 경기-강원, 충청도, 전라북도, 그리고 경상북도 권역을 중심으로 각 권역당 3개 지역 그리고 지역당 3개 지점을 두고 조사하였다. 단감은 모두 3종으로, brown spot (Fusicladium levieri), black leaf spot (Adisciso kaki), 그리고 black spot (Phoma kakivora)을 조사하였고 국내 단감 주생산지인 경상남도와 전라남도 권역을 중심으로 각 권역당 3개 지역 그리고 지역당 3개 지점을 두고 조사하였다. 감귤 대상 병은 모두 2종으로, citrus scab (Elsinoë australis), Septoria spot (Septoria citri)을 조사하였고 감귤 주생산지인 제주권역을 중심으로 조사하였다. 모두 9종에 대한 예찰조사는 2019년 4월부터 10월까지 2주간격으로 실시하였다. 예찰조사결과 주요 수출대상 과수인 포도, 단감, 감귤의 국내미기록병 9종에 대한 원인병원체는 발견되지 않았다. 이 연구를 통해 식물병을 조기에 탐지할 수 있는 전국적인 모니터링 시스템을 구축하였고, 국외 외래유입병들의 예찰조사를 위한 지역 거점을 확보하였다고 평가된다.