• KIEAE Journal
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• 제12권4호
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• pp.105-110
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• 2012

Recently, all of the world are facing with a serious environmental crisis of global warming due to excessive energy consumptions. The Korean Government, taking over 97% of dependence on foreign energy, has made various efforts on reducing energy and greenhouse gas emission under the motto of "Low-Carbon Green Growth". Since the building sector takes 24% of domestic energy consumption, many design standards and regulations on saving energy in new buildings have been established. However, applications of energy saving designs and techniques on the remodeling process at deteriorated buildings including educational ones have been lack. Under a situation where the number of deteriorated schools accounts for up to 50%, this paper evaluated the performances of factors for reducing energy at deteriorated middle school buildings through an energy simulation tool on a standard school model. As a result, among factors of insulation, window's SHGC, southern louver, indoor setup temperature, and system efficiency, all other factors except window's SHGC and southern louver proved contribute to reduce energy at deteriorated middle school buildings, compared with the baseline energy consumption.

• 한국농촌건축학회논문집
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• 제13권4호
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• pp.17-24
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• 2011

This research is according to the a future-oriented strategy, low-carbon green growth, and it is a basic research for dissemination of rural housing standard plan. Through the survey of plans use, we look at ways to rural housing standard plan use and then needed to establish measures for this. Looking at the type of used plans, we can find several points. One of them, 19 kinds of rural housing standard plans were used among the 61 total cases. Almost all change the plan, the reasons is different for the condition of the land, such as site conditions, family members, personal preferences, house color or material. A few cases have been constructed as rural housing standard plans, but rural housing standard plans are important data for the rural resident to determine plans, and it has an important role in the rural housing design process. Common features of the many rural houses is concrete structure, two stories, and construction period is two to three months. Land area is $300m^2$ to $600m^2$, building area is $71m^2-110m^2$. Heating system is an oil boiler.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.91-91
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• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• Advances in Energy Research
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• 제3권1호
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• pp.11-30
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• 2015

The covenant of Mayors initiative includes the commitment of the municipalities-signatories to reduce voluntarily the greenhouse gas emissions over 20--- by 2020 within their boundaries and obligates them to develop and submit an energy consumption analysis and a sustainable energy action plan within a year from the adhesion. The present paper discusses the energy profile of three medium-sized north-eastern Greek Municipalities (Kavala-MoK, Alexandroupolis-MoA, Drama-MoD) through the analysis of their municipal energy balance. The results of the total final energy consumption per capita include 14.10MWh/capita, 14.24MWh/capita and 12.91MWh/capita for MoK, MoA and MoD respectively. The analysis highlighted the increased energy consumption of the private sectors, namely residential and tertiary building sand private transport. The assessment of the municipalities' energy profiles along with examination of national regulations and action plans and investigation of best available practices within the Covenant of Mayors shaped the development of the sustainable energy action plans of the examined municipalities that is presented in this paper. The proposed pathway towards low-carbon municipalities can be considered a representative case study and a starting point for other municipalities with similar characteristics.

• Advances in concrete construction
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• 제5권5호
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• pp.539-561
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• 2017

In this study, the effects of initial damage of concrete columns on the post-repair performance of reinforced concrete (RC) columns strengthened with carbon-fiber-reinforced polymer (CFRP) composite are investigated experimentally. Four kinds of compression-damaged RC cylinders were reinforced using external CFRP composite wraps, and the stress-strain behavior of the composite/concrete system was investigated. These concrete cylinders were compressed to four pre-damaged states including low -level, medium -level, high -level and total damage states. The percentages of the stress levels of pre-damage were, respectively, 40, 60, 80, and 100% of that of the control RC cylinder. These damaged concrete cylinders simulate bridge piers or building columns subjected to different magnitudes of stress, or at various stages in long-term behavior. Experimental data, as well as a stress-strain model proposed for the behavior of damaged and undamaged concrete strengthened by external CFRP composite sheets are presented. The experimental data shows that external confinement of concrete by CFRP composite wrap significantly improves both compressive strength and ductility of concrete, though the improvement is inversely proportional to the initial degree of damage to the concrete. The failure modes of the composite/damaged concrete systems were examined to evaluate the benefit of this reinforcing methodology. Results predicted by the model showed very good agreement with those of the current experimental program.

• Structural Engineering and Mechanics
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• 제71권3호
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• pp.283-290
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• 2019

In global competition manufacturing companies have to produce modern, new constructions from advanced materials in order to increase competitiveness. The aim of my research was to develop a new composite cellular plate structure, which can be primarily used for structural elements of road, rail, water and air transport vehicles (e.g. vehicle bodies, ship floors). The new structure is novel and innovative, because all materials of the components of the newly developed structure are composites (laminated Carbon Fiber Reinforced Plastic (CFRP) deck plates with pultruded Glass Fiber Reinforced Plastic (GFRP) stiffeners), furthermore combines the characteristics of sandwich and cellular plate structures. The material of the structure is much more advantageous than traditional steel materials, due mainly to its low density, resulting in weight savings, causing lower fuel consumption and less environmental damage. In the study the optimal construction of a given geometry of a structural element of a road truck trailer body was defined by single- and multi-objective optimization (minimal cost and weight). During the single-objective optimization the Flexible Tolerance Optimization method, while during the multi-objective optimization the Particle Swarm Optimization method were used. Seven design constraints were considered: maximum deflection of the structure, buckling of the composite plates, buckling of the stiffeners, stress in the composite plates, stress in the stiffeners, eigenfrequency of the structure, size constraint for design variables. It was confirmed that the developed structure can be used principally as structural elements of transport vehicles and unit load devices (containers) and can be applied also in building construction.

• World Technopolis Review
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• 제7권2호
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• pp.125-134
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• 2018

The purpose of this article is to introduce and describe the case of Fukuoka Next-generation Social System Creation Hub based on the conceptual framework of regional innovation platform strategy. In short, it is a "government-issued" regional innovation platform strategy to improve innovativeness with limited creative capital through "borrowing" not money but network, wisdom, know-how, and ideas from each other between some stakeholder groups in a region. The Fukuoka Industry, Science & Technology Foundation, which is the coordinating institution of the whole program, plays the role of a platformer to unify various projects into the program crossing borders between stakeholder groups for building regional innovation platforms that lends intensive support to feedback loops between the program facilitator and its partners in the program. Thanks to being a government-issued one, it could be tied together with some wide ranging issues of policy on social innovations, such as the "low carbon society" or the "health and longevity society." But at the same time, it is a concern that many regional research institutions that have innovative potential and diverse ideas become governed by the platform without their noticing it and dealt with in the same way based on "selected" and "designated" strategic goals. Therefore, it seems that a regional innovation platform strategy is a kind of "double-edged sword" in public policy in the era of "panopticism of bureaucratic society" in Japan.

• Smart Structures and Systems
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• 제28권6호
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• pp.727-735
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• 2021

Recently, non-destructive health monitoring methods such as magnetic flux leakage (MFL) method, have become popular due to their advantages over destructive methods. Currently, numerical study on this field has been limited to simplified studies by only obtaining MFL instead of induced voltage inside coil sensor. In this study, it was proposed to perform a novel numerical simulation of MFL's coil sensor by considering vital parameters including specimen's motion with constant velocity and saturation status of specimen in time domain. A steel-rod specimen with two stepwise cross-sectional changes (i.e., 21% and 16%) was fabricated using low carbon steel. In order to evaluate the results of numerical simulation, an experimental test was also conducted using a magnetic probe, with same size specimen and test parameters, exclusively. According to comparative results of numerical simulation and experimental test, similar signal amplitude and signal pattern were observed. Thus, proposed numerical simulation method can be used as a reliable source to check efficiency of sensor probe when different size specimens with different defects should be inspected.

• Structural Engineering and Mechanics
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• 제89권4호
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• pp.349-362
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• 2024

High-performance fiber-reinforced cement composites (HPFRCC) are new materials created and used to repair, strengthen, and improve the performance of different structural parts. When exposed to tensile tension, these materials show acceptable strain-hardening. All of the countries of the globe currently seem to have a need for these building materials. This study aims to create a low-carbon HPFRCC (high ductility) that is made from materials that are readily available locally which has the right mechanical qualities, especially an increase in tensile strain capacity and environmental compatibility. In order to do this, the effects of fiber volume percent (0%, 0.5%, 1%, and 2%), and determining the appropriate level, filler type (limestone powder and silica sand), cement type (ordinary Portland cement, and limestone calcined clay cement or LC3), matrix hardness, and fiber type (ordinary and oxygen plasma treated polypropylene fiber) were explored. Fibers were subjected to oxygen plasma treatment at several powers and periods (50 W and 200 W, 30, 120, and 300 seconds). The influence of the above listed factors on the samples' three-point bending and direct tensile strength test results has been examined. The results showed that replacing ordinary Portland cement (OPC) with limestone calcined clay cement (LC3) in mixtures reduces the compressive strength, and increases the tensile strain capacity of the samples. Furthermore, using oxygen plasma treatment method (power 200 W and time 300 seconds) enhances the bonding of fibers with the matrix surface; thus, the tensile strain capacity of samples increased on average up to 70%.

• 한국구조물진단유지관리공학회 논문집
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• 제23권2호
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• pp.37-43
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• 2019

이 연구는 고성능 섬유보강 복합체(HPFRCC)의 전자파 차폐성능을 향상시키기 위한 목적으로 전기전도도, 전자파 차폐능, 역학적 강도를 조사하였다. 강섬유, 제강슬래그 미분말, 카본블랙이 전도성재료소 HPFRCC 배합에 첨가되었다. 또한, MWCNT를 수 분산 시켜 제조된 2% wt. CNT 용액을 사용하였다. 실험 결과, HPFRCC의 전기전도도는 1% 카본블랙이 첨가된 시편을 제외하고는 매우 낮은 특성을 보였다. 시멘트 매트릭스의 미세구조는 시간에 따라 변하였고, 그로 인해 HPFRCC의 전기전도성 네트워크에 부정적인 영향을 끼쳤다. 0.083 S/cm의 전도도를 갖는 HC1 시편의 경우, 수분에 의한 효과를 배제하기 위하여 72시간 60도에서 건조 양생한 후에 측정한 전기전도도가 0.0003 S/cm로 상당히 감소하였다. 전자파 차폐 성능에 가장 중요한 인자는 강섬유인 것으로 나타났으며, 반면 카본블랙과 제강슬래그 미분말의 효과는 미미하였다. 전기전도도와 전자파 차폐능의 상관관계는 이 연구에서는 뚜렸한 경향성을 나타내지는 않았다.