The purpose of this paper is to demonstrate to the practicing engineers, how to apply the advanced composite materials theory to the slab bridges. For general construction material used, there is certain theoretical limit in sizes. For super slab bridges construction, the reduction in panel weight is the first step to take in order to break such size limits. For a typical slab bridges panel, both concrete and advanced composite sandwich panels are considered. The concrete panel is treated as a special orthotropic plate. Advanced composite sandwich panels are considered as a self-weights less than one tenth of that of concrete panel, with deflections less than that of the concrete panel. This conclusion gives good guide line for design of the light weight of slab bridges.

The air brake chamber is needed higher sealing performance and durability for the safety and confidential operation, especially, in brake systems of commercial vehicle. For higher sealing, we applied new clamping technique differentiated methods of other global manufacturers. And we developed the power spring and spring guide made from light engineering plastic with high durability in repeated condition. We also have achieved the basic performance test like sealing test in compressed air and various environment tests in dust and salty water for new manufactured air brake chambers. As a result, the air brake chamber applied light weight and high durable power spring is satisfied all demand specification conditions for commercial vehicle

Recently, sewer–pipe constructions replacing deteriorated pipes are currently underway in the downtown area. To resolve many problems in the conventional method of open-cut construction, lining-board system using light-weight GFRP panels is developed. The pultruded GFRP panels can be successfully used for the developed lining-board system as temporary decks and retaining walls in virtue of light weight, high strength and high durability. In this paper, the structural safety and serviceability of the lining-board system are examined through FE analyses and experiments. Further more, a field application of the lining-board system is presented. The field application shows that quality and environment of construction can be significantly improved.

PURPOSES: The purpose of this paper is to demonstrate to the practicing engineers, how to apply the advanced composite materials theory to the road structures. For general construction material used, there is certain theoretical limit in sizes. For super road structure construction, the reduction in panel weight is the first step to take in order to break such size limits. METHODS: For a typical road structures panel, both concrete and advanced composite sandwich panels are considered. The concrete panel is treated as a special orthotropic plate. RESULTS: All types of advanced composite sandwich panels are considered as a self-weights less than one tenth of that of concrete panel. The concrete panel is treated as a special orthotropic plate to obtain more accurate result. CONCLUSIONS: Advanced composite sandwich panels are considered as a self-weights less than one tenth (10%) of that of concrete panel, with deflections less than that of the concrete panel. This conclusion gives good guide line for design of the light weight of road structures.

The purpose of this study is to look into the weight-lightening phenomenon of the roof structure of some Hanok(韓屋), the Korean traditional houses found from the survey on the distribution and actual state of urban traditional houses existing in the whole region of Jung-gu, Daegu, Korea. As a result of judging from the pre-test of building registers for the research area, approximately 5,000 wood structure houses were found. A field data survey based on these findings showed that there are 1,752 Hanok houses. And the further classification of the Korean traditional houses by roof structure type shows that about 35% of them underwent weight lightening. While this kind of light-weight Hanok is different from the concept of traditional Hanok, they also show the survival method of Hanok that reflects the economical and technological phases of that period. It is expected that deeper understanding on the urban traditional houses will be possible through carrying out in-depth researches on techniques of the light-weight roof structure of the urban traditional houses that are supposed to have functioned as dwellings as commercial products.

대형구조물 설계 건설시 가장 큰 제한 조건은 모든 건설재료에는 치수의 한계가 있다. 따라서 본 논문 에서는 고전 보 이론에 의하여 단순 지지된 비등방성 슬래브의 처짐값을 구한 후 그 값을 비교 하였고, 특별 직교이방성 판 이론에 의하여 콘크리트와 샌드위치 교량의 물성을 비교하여 그 결과에 따른 처짐비와 강성값을 비교하였다. 경계조건은 임의의 경계조건을 갖는 판에 대한 해석해가 없기 때문에 부득이하게 네변이 모두 단순지지 되었을 경 우로 해석을 하였고 복합재료의 인장강도는 콘크리트나 강재보다 훨씬 높으므로 비교대상은 처짐으로 하였다. 즉, 철근 콘크리트와 동일하거나 작은 처짐을 일으키는 몇 가지 샌드위치판을 선택하여 고려하였다.

Robotic manipulators are increasingly deployed in complex environments or to perform complex tasks. Studies on dual-arm-robots have been continually carried out in robotics areas to provide robots in dangerous environments, similar to those which human beings would be normally in, without a special change to the working environment. In previous study, a dual-arm-robot has been designed. The robot, however, has some defects in its heavy weight and big shape. In order to reduce weight of an arm robot, the robot has been designed using a hollow-shaft-servo- assembly. The hollow-shaft-servo-assembly is composed of a hollow-shaft-servo-motor, a hollow- shaft-harmonic-drive, a hollow-shaft-brake, a hollow-shaft-encoder, and a servo-drive.

현재, 포장시스템의 노상과 보조기층의 다짐관리는 들밀도 시험을 이용한 상대 다짐도와 평판재하시험이 널리 쓰이고 있다. 하지만, 이 두 시험법은 노상과 보조기층의 다짐관리를 평가하기엔 시간과 비용이 많이 소요되며 실측 값을 얻기에도 매우 어렵다. 이에 본 연구에서는 노상과 보조기층 시공 현장에서 다짐관리를 보다 빠르고, 적은 비용으로 측정 할 수 있는 소형충격재하시험들의 비교분석을 실시한 후, LFWD시험을 다짐평가장비로 제안하였다. 또한, 노상과 보조기층의 실내시험 및 현장 시험을 통하여 국내 도로 하부구조 재료 특성에 따른 ELFWD와 상대 다짐도, K30, 설계 MR 값과의 상관관계를 제안하였다.

Sedum속 식물을 이용하여 저관리 경량형 시스템으 로 만든 옥상녹화지에서 무관리 상태에서 3년간 생장 및 인공토양 변화를 조사한 결과 다음과 같았다. 서울 시립대 자연과학관 6층 옥상에 2003년 6월에 9종의 Sedum 식물을 식재하여 3년간 무관리 식물상태를 관 찰한 결과 Sedum 식물 9종(돌나물, 땅채송화, 바위채 송화, 큰꿩의비름, 기린초, 섬기린초, 가는잎기린초, ‘Spurium’, ‘Diffusum’) 중 땅채송화와 바위채송화는 1년차 때도 생육이 좋지 않았고 3년차 때는 완전히 사라지고 다른 이입식물로 채워졌다. 기린초와 가는잎 기린초는 1년차에 비해 생육이 감소하는 경향이 있었 으나 다른 5종의 식물은 대부분 생장이 증가하였고 관 상가치도 높았다. 돌나물을 6가지(Pm1Pr1, Pm1Pr1V1, Pr1C1, Pr1V1C1, Pm1V1, V1C1) 배지에 재식한 후 배 지 간 변화를 살펴본 결과 pH는 2003년과 2005년에 큰 변화를 보이지 않았으며 EC는 2005에 확연히 높 았다. 질소, 인, 칼륨은 식재년도(2003)에 비해 2005 년도에는 유사하거나 낮은 것을 볼 수 있었다.

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

환경변화에 따른 작물생체의 반응을 근속하고 정확히 해석하기 위하여, 로드셀과 마이크로컴퓨터를 이용하여 수경조건에서 생체중을 비파괴적으로 연속측정할 수 있는 시스템을 개발 하였다. 또한 이 시스템을 이용하여 양액의 이온농도 및 명암 조건에 따른 상추의 생장반응을 조사 하였던 바, 그 결과를 요약하면 다음과 같다. 가. 작물의 생체중을 비파단 연속적으로 측정할 수 있는 이 장치의 측정오차는 측정범위 0-2000g에서 0.05%인 土1.0g 이하로 나타났다. 나. 로드셀에서 출력된 지시중량은 수면위의 생체중량과 잘 일치하였다. 다. 상추의 생체중은 정식후 18일에 정식 당시에 비해서 44배 정도 증가하였고, 상대생장율은 정식후 5일까지는 미약하였으나 이후에 급격히 높아져 정식후 13일에 최대에 달하여 29.6% day-1 이었다. 정식후 18일간의 상대생장율은 10.7-29.6% day-1 범위에 있었다. 라. 양액의 무기 이온 농도에 따른 상추의 생장량은 EC 1.4-2.2mS/cm 에서 가장 높았으며, EC 0.7 이하나 2.8 이상에서는 떨어졌는데, 특히 지하부의 생장량은 2.8 이상의 고농도에서 현저히 낮았다. 마. 양액의 이온 농도에 따른 생체중량의 증가속도는 정식후 7일까지는 큰 차이가 없었으나 이후 차이가 나기 시작하여 정식후 20일에는 양액의 이온농도에 따라 큰 차이가 있었다. 사. 암흑 처리후 12시간 까지는 정상적으로 생체중이 증가 하였으며, 이후 78시간까지도 완만한 증가 양상을 나타내었으나 그 이후에는 감소하는 경향이었다. 아. 명조건에서 암조건으로 환경이 변화함에 따라 생체중량은 급격히 증가하였고 반대의 조건에서는 일시적인 생체중 감소가 있었는데, 이와 같은 양상은 생육단계, 광조사 시각 및 시간을 달리하 여도 같은 경향이었다.

This study was conducted examine the mechanical properties of LEFC in relation to the type of light weight aggregate and replacement ratio. For the specimen, different replacement ratio was used for recycled waste ALC and the bottom ash light weight aggregate respectively. The tests revealed that 60% of the waste ALC light weight aggregate is suitable for securing the optimal strength and light weight of the LEFC.

This study was conducted examine the mechanical properties of LEFC in relation to the type of light weight aggregate and replacement ratio. For the specimen, different replacement ratio was used for recycled waste ALC and the bottom ash light weight aggregate respectively. The tests revealed that 60% of the waste ALC light weight aggregate is suitable for securing the optimal strength and light weight of the LEFC.

Insulation materials used for building save energy and can be classified into inorganic and organic materials. Organic insulation emits toxic gases in a fire annd has lower water resistance. Inorganic insulation is heavy and has poorer thermal performance than that of organic material. This study evaluated the physical properties and fire resistance of lightweight inorganic insulation foaming material made of waste glass powder. The test results showed that the inorganic material performed well with low density and low thermal conductivity for an insulation material. Foam insulation material manufactured from glass powder was sufficient as a fire-resistant product.