• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.3
• /
• pp.152-159
• /
• 2010

Recently, the public interest in eco-friendly material and structure has been increasing and many Hwang-toh researches are being actively performed. Hwang-toh is one of the traditional environment friendly construction materials used as a construction and plastering material. Hwang-toh has many advantages as construction material due to its high heat storage capacity, auto-purification, antibiotic ability, and infrared ray emission characteristics. But, currently it has not been developed into construction material and used in modern construction due to its low strength and dry shrinkage cracking prone characteristics. According to the recent researches and study results, Hwang-toh can be used as a natural pozzolanic material like fly-ash or pozzolan. In this study, mechanical properties and structural flexure behavior experiments of slag, recycled PET fiber, and Hwang-toh added concrete are carried out. The test results showed that drying shrinkage of concrete mixed with Hwang-toh has lower compressive strength and elastic modulus than those of control cement concrete specimen, but it has the similar flexural behavior in reinforced concrete beams.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.235-235
• /
• 2009

본 연구는 친환경 신새생 에너지를 이용한 전력 시스템을 개발함으로써 전력 IT인 Smart Grid 기술 활용과 더불어 예기치 못한 정전으로부터 중요한 전자 장비를 보호하는 UPS 기능을 갖는 친환경 3.0kW급 하이브리드 연료전지 UPS 시스템을 개발하는 것이다. 이를 위하여 시뮬레이션 기법을 이용하여 소형 경량화에 따른 구성 부품 배치 합리화 및 발생열 최적화 설계를 도출하였으며, 연료전지용 장수명 밀폐형 Ni-MH전지, 고효율 전력변환기, 하이브리드 PMS의 설계 및 제작과 개발된 3kW급 하이브리드 연료전지 UPS 시스템 기능 및 성능 평가를 공인 기관에서 검증받았다. 본 연구를 통하여 개발된 연료전지용 장수명 100Ah급 밀폐형 Ni-MH전지는 밀폐화와 더불어 장수명화 및 저온 방전 특성이 우수한 뿐만 아니라 KS규격을 모두 만족하였으며, 내구성도 DOD100%에서 1,093cycle의 결과를 얻을 수 있었다. 또한, 전지 설계 및 제작 기술뿐만 아니라 양산화 관련 기술들이 개발되어 향후 고용량, 고출력, 장수명의 축전지가 필요로 하는 분야에 적용될 수 있는 기반이 마련되었다. 또한 고효율 전력 변환기 및 연료전지과 축전지를 조절하는 PMS을 탑재한 소형 경량화 된 친환경 IT제품의 이미지를 구현하였다.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.5
• /
• pp.103-111
• /
• 2010

This research aims to make a contribution to the development of waterproofing technique for rooftops by analyzing and understanding the problems of the currently used waterproofing method and their causes. To do this, this research developed an eco-friendly waterproofing method that supplements the weaknesses of the conventionally used method by analyzing the problems of leakage resulting from design and construction work to diminish leakage, improving the quality of construction work, reducing labor required and the period of construction, and improving environment alconditions. The characteristics of the newly developed method are comparatively analyzed with the convention alpractices, and are evaluated on the site.

• Journal of IKEEE
• /
• v.20 no.2
• /
• pp.200-204
• /
• 2016

In this paper, we have estimated the performance of an overflow valve for EURO type CRDI(common rail direct injection) engine. In order to implement the overflow valve with friendly circumstance, it is necessity for considering spring load. Especially, the performance evaluation of diesel car with accuracy control will be considered a mileage improvement and circumstance regulation. In order to evaluate the performance of overflow valve, The leak test system checks the pressure, switching time and operating time under 3.0 bar below 100 cc, 3.3 bar among 150 cc and 200 cc, finally 4.0 bar upper 250 cc.

• Journal of the Korea Convergence Society
• /
• v.12 no.4
• /
• pp.87-94
• /
• 2021

While the shielding substances of radiation shields in medical institutions are beginning to be replaced by environmentally friendly materials, radiation protection according to the shielding properties of environmentally friendly substances is becoming an important factor rather than the existing lead shielding properties. Tungsten and barium sulfate are representative shielding materials similar to lead, and are made in sheets or fiber form with eco-friendly materials. Ytterbium is an impermeable material used as a fluorine compound in the dental radiation field. This study aims to evaluate the shielding performance in the x-ray shielding area by comparing the shielding properties of ytterbium by energy band and that of existing eco-friendly materials. When three types of shielding sheets were fabricated and tested under the same process conditions, the shielding performance of the medical radiation area was about 5 % difference from tungsten. Furthermore, shielding performance was superior to barium sulfate. In the cross-sectional structure of the shielding sheet, there was a disadvantage that the arrangement of particles was not uniform. Ytterbium oxide showed sufficient potential as a medical radiation shielding material, and it is thought that it can improve the shielding performance by controlling the particle arrangement structure and particle size.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.2
• /
• pp.170-178
• /
• 2015

In this study, it was developed eco-friendly alkali-activated slag fiber reinforced concrete using ground granulated blast furnace slag, alkali activator (water glass, sodium hydroxides), and steel fiber. Eight reinforced concrete beam using alkali-activated slag concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, mixed/without of steel fiber. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The reinforced concrete beams using the eco-friendly alkali-activated slag fiber reinforced concrete was failed by the flexure or flexure-shear in general. In addition, the maximum strength increased with the adding the mol of sodium hydroxide, and the specimen reinforced the steel fiber showed the value of maximum strength which is increased by 15.8% through 25.9%. It is thought that eco-friendly alkali-activated slag fiber reinforced concrete can be used with construction material and product to replace normal concrete. If there is applied to structures such as precast concrete member and production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.

• Journal of the Korea Concrete Institute
• /
• v.25 no.3
• /
• pp.261-269
• /
• 2013

In this study, it was developed eco-friendly inorganic binding material concrete using ground granulated blast furnace slag and alkali activator (water glass, sodium hydroxides). Eight reinforced concrete beam using inoganic binding material concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, type of admixture and admixture. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The eco-friendly concrete using inorganic binding material encouraged alkali activation reaction was rapidly hardening speed and showed possibility as a high strength concrete. Also, the RC beams using new materials showed similar behavior and failed similarly with RC beam used portland cement. It is thought that eco-friendly inorganic binding material concrete can be used with construction material and product as a basic research to replace cement concrete. If there is application to structures in PC member as well as production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.

• International Journal of Highway Engineering
• /
• v.13 no.2
• /
• pp.85-93
• /
• 2011

This study experimented to evaluate the environment friendly high performance ternary cement concrete deck overlay pavement using mineral admixture such as fly ash and ground granulated blast-furnace slag. It was measured to find best binder mixing according to replacement rate of mineral admixture with compressive strength and flexural strength. After finding best binder, it is also experimented to evaluate durability on chloride penetration resistance, freezing- thawing resistance, scaling resistance of deicing chemicals, abrasion resistance, alkali-silica reactivity test and bonded environment friendly high performance ternary cement concrete deck overlay pavement experimented to evaluate bonded old deck and new concrete overlay pavement using special polymer cement mortar. In additions, bonded environment friendly high performance ternary cement concrete deck overlay pavement by experimental construction was evaluated at interchange bridge of North Yeoju. Result, examination was indicated better binding with binder replacement of cement 70%, ground granulated blast-furnace slag 15% and fly ash 15%. And special polymer cement mortar used in old deck and new overlay concrete was indicated better bonding both laboratory and construction.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.04a
• /
• pp.77-82
• /
• 2009

Many countries have been interested in sustainable development of buildings for environmental preservation. Thus it is significant to assess building envelopes in terms of $CO_2$ emissions owing to Kyoto Protocol. In this paper, a Double Skin Facade(DSF) installed in a general office building was assessed by $CO_2$ emissions(one of the performance-based assessment). To predict $CO_2$ emissions caused by the building energy consumption, the dynamic simulation program(Energy Plus) and $CO_2$ emission factor was used. Because DSF has various airflow regimes, pre-simulation runs were conducted to decide proximate optimal airflow regimes depending on seasonal variation. It is shown that the DSF can achieve 17.1-36.5% of annual energy savings.

• Journal of Ocean Engineering and Technology
• /
• v.30 no.1
• /
• pp.57-67
• /
• 2016

As a new technical approach, an attempt was made to realize a photovoltaic system for an eco-environmental leisure ship by simultaneously actuating nine photovoltaic solar panels in association with the application of a sail-controlling system using wind energy. In this approach, the photovoltaic system consisted of a solar module, an inverter, a battery, and the relevant components, while the sail-controlling device was equipped with sail up/down and mast turning systems. The previously mentioned eco-environmental leisure ship utilizes a photovoltaic hybrid system that uses solar and wind energy as renewable energy sources. Furthermore, this research included a performance evaluation of the manufactured prototype, the acquisition of the purposed quantity values, and development of the purposed items. The significant items, including the sail up/down speed (seconds) and mast turning angle (degrees) were evaluated for a performance test. A wind direction sensitivity of 90% and maximum instant charging power of 900 W were also obtained in the process of the performance evaluation. In addition, the maximum sail time was also evaluated in order to acquire the optimum value. The performance evaluation showed that the prototype with a photovoltaic hybrid system was suitable for sailing an eco-environmental leisure ship using solar and wind energy.