• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.163-163
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• 2016

아연계 도금 강판은 우수한 내식성을 가지며 특히 아연의 희생방식기구에 의해 철의 부식을 억제하므로 선박, 건축자재, 전자기기 및 자동차 등 다양한 분야에서 그 수요와 사용범위가 증가하고 있다. 또한 도금 조성비 변화 및 다양한 표면처리 방법을 통해 가혹한 환경에서의 우수한 내식성에 대한 연구가 활발히 진행되고 있다. 그 중 갈바륨(Galvalume)은 55%의 알루미늄(Al)과 45%의 아연(Zn)으로 되어 있으며, 아연의 장점인 희생방식성과 내알카리성, 알루미늄의 장점인 내구성과 내열성, 내산성을 이상적으로 결합시킨 알루미늄(Al)-아연(Zn) 고내식 합금용융도금강판이다. 본 연구에서는 갈바륨 소재를 여러 산업현장에서 강관 형태로 사용할 경우의 내식성을 파악하기 위해 갈바륨 강관과 기존에 사용되고 있는 용융도금재인 용융아연도금 강관을 비교하며 실험을 진행하였다. 냉간압연강관에 용융아연도금 약 $25{\mu}m$, 갈바륨 약 $20{\mu}m$ 두께로 제작된 강관을 사용하였으며 제작된 도금층 표면 모폴로지는 SEM을 통해 관찰하였고, XRD 분석을 통해 결정 구조를 확인하였다. 또한 5% 염수분무 환경 중 노출시험(Salt spray test), 3% NaCl 용액에서의 자연침지 시험 및 3% NaCl 용액 중 전기화학적 양극분극 시험을 진행하여 평가하였다. 5% NaCl 환경에서의 염수분무 시험 결과 용융아연도금의 경우 단면에서는 90시간, 표면에서는 260시간 경과 후 적청이 발생하였다. 반면, 갈바륨의 경우에는 단면에서 210시간 경과 후에 적청이 발생하였고, 표면의 경우에는 900시간 이상에서도 적청이 발생하지 않았다. 이 결과를 통해 용융아연도금에 비해 갈바륨 도금의 내식성이 단면에서는 3배, 표면에서는 4~5배 이상 향상된 것으로 확인되었다. 또한 3% NaCl 용액 중 자연침지 시험 결과 용융아연도금 강관 표면은 24시간 경과 후 열화부를 중심으로 흑변하는 것을 확인할 수 있었으나 갈바륨의 경우에는 900시간 이상 실험이 진행되는 동안 No Scribe 및 Scribe 시편 모두 외관상 변화가 거의 없었다. 단면의 경우, 용융아연도금 시편은 900시간 이상 실험이 진행되는 동안 외관상 변화가 없었으며, 갈바륨 시편의 경우 300시간 경과 하면서 흰색의 아연 부식생성물이 나타났으나 900시간 이후로도 적청은 발생하지 않았다. 자연전위 측정결과 용융아연도금 및 갈바륨 시편 모두 유사한 전위거동을 나타냈지만 단면의 경우 갈바륨 시편이 용융아연도금에 비해 안정적인 거동을 보였다. 3% NaCl 용액 중 전기화학적 양극 분극 시험 결과 용융아연도금이 갈바륨에 비해 귀한 방향의 부식 전위 값을 나타냈으며, 부식 전류밀도도 용융아연도금이 갈바륨에 비해 더 높은 값을 나타내는 것을 확인할 수 있었다. 이상의 염수분무시험, 자연침지시험 및 전기화학적 양극분극시험을 통해 종합적으로 분석-고찰하여 보면, 그 부식이 진행되는 과정은 융융아연도금과 달리 갈바륨 도금의 경우가 다단계적인 부식 과정을 거치면서 우수한 내식 특성을 나타낸다는 것을 알 수 있었다. 즉, 갈바륨 도금은 그 도금 막에 분포된 합금상 원소 성분들이 상호 갈바닉(Galvanic) 작용하며 형성된 부식생성물이 수평적으로 자체 차단(Barrier) 역할을 하는 과정과 부분적 부식-회복 과정을 거치면서 다단계적으로 부식속도를 감소시키게 된다는 것을 확인 할 수 있었다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.431-438
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• 2016

Recently, Both rapid economic growth and high-quality native finishing materials demand in buildings such as local infrastructure facilities and cultural facilities have increased along with local quarries. So, increasing local quarries and environmental pollution occurred in quarries get the eyes to damaged area of the surroundings. As an example, carcinogen such as solid formed to fixing asbestos and dust have damaged to local resident. Especially, Radon gas released from asbestos can exist everywhere on earth, released soil and rock as radioactive substances, can be caused lung cancer followed by a smoking. When pollution source to indoor air quality that lacking ventilation rate of the residential building moved in a cycle, human responses such as headache, dizziness, etc. get appear, so on it threatened resident's physical condition. Thus, we need to urgent attention to reduction harmful substance. In the case of radon gas of the pollution source to indoor air quality in housing, it has characteristic that keep on going through half-life released from source, we need to control radon gas source than source removal. We set on vermiculite addition ratio to 10% which has harmful substances adsorption performance, proceed experiment to basalt waste rock addition ratio 50, 60, 70, 80(%). The result of an experiment, based on 'KS F 4035, precast terrazzo', we can be obtainable in the best terrazzo at basalt waste rock addition ratio 70%.

• Journal of Korean Association for Spatial Structures
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• v.8 no.5
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• pp.47-58
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• 2008

Spatial structure is an appropriate shape that resists external force only with in-plane force by reducing the influence of bending moment, and it maximizes the effectiveness of structural system. With this character of the spatial structure, generally long span is used. As a result, large deflection is accompanied from the general frame. the structure is apt to result in a large deflection even though this structure experiences a small displacement in absence. Usually, nonlinear analysis in numerical analysis means geometric nonlinearity and material nonlinearity and complex nonlinearity analysis considers both of them. In this study, nonlinear equation of equilibrium considering geometric nonlinearity as per finite element method was applied and also considered the material nonlinearity using the relation of stress-strain in element. It is applied to find unstable result for tracing load-deflection curve in the numerical analysis tech. especially Arc-length method, and result of the analysis was studied by ABAQUS a general purpose of the finite element program. It is found that the present analysis predicts accurate nonlinear behavior of plane and space truss.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.87-94
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• 2000

Crack sealing, a routine and necessary part of pavement maintenance, is a dangerous, costly, and labor-intensive operation. Within the North America, about ${\$}200$ million is spent annually on crack sealing, with the Texas Department of Transportation (TxDOT) spending about ${\$}7$ million annually (labor alone accounts for over 50 percent of these costs). Prompted by concerns of safety and cost, the University of Texas at Austin, in cooperation with TxDOT and the Federal Highway Administration (FHWA) has developed a unique computer-guided Automated Road Maintenance Machine (ARMM) for pavement crack sealing. In 1999, successful field tests have been undertaken in 8 States around the U.S. This paper first describes significance of the automated crack sealing and technical advances in automated crack sealers including the ARMM, developed in the U.S. It then discusses the ARMM's field implementation and performance evaluation results, and improvements and modifications suggested through the technology evaluation during the field trials. Current research efforts and future work plans in its further development are also presented in this paper.

• Korean Journal of Construction Engineering and Management
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• v.16 no.6
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• pp.112-123
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• 2015

Many disputes are happened with various causes in overseas construction projects. One of major disputes is closely related with nominated subcontractors (NSC). This paper investigates 30 judical precedents for Singapore, Malaysia and Hongkong to analyze the detailed disputes related with the NSC, and then the judical precedents are classified into 6 categories: Delay and Defect Trouble (T1), Contract Relation (T2), Payment Trouble (T3), Set-off (T4), Liquidation (T5) and so forth (T6). According to the analytical results, the frequency of occurrence of disputes is considerably related with social and economical changes, and the dispute between NSC and employer for residential and commercial building projects is the most frequently happened case. As the results of analysis, therefore, it is concluded that the employer needs to response aggressively to the problems related with NSC, and it is also important to make the council for communication among related bodies. Furthermore, the institutional reform that make the role and the responsibility of employer consistent under considering contract terms and conditions is considered as the most important and fundamental issue.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.1019-1022
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• 2007

Recent construction projects are becoming larger, more complex and higher rising. Accordingly, necessity of the VE is emphasized as more suitable for expense, function and quality. However, the VE is not functional because of difficulty of application process or of the methods in use in the field of construction. One of the alternative is to introduce the incentive system to activate the VE in the field of construction. By using the incentive system, employers can reduce the relevant project's prime cost and builders will maximize profit creation. In domestic case, they presented the systematic support policy 'Technical development compensation system' which is similar to the 1992 American's VE incentive system about builder's technical development effort but the result was not positive. This study investigates both domestic and other country's construction VE incentive system and reported problems in the construction VE incentive system to executives and construction VE experts. From this survey, conclusions were drawn about problems in the domestic construction VE incentive system's similarity system: 'Insufficiency of the construction VE incentive's article and standards', 'Insufficiency of the appraiser of the construction VE and of the full charge department' etc. I had interviews with the experts of the construction VE which were based on the above-mentioned problems and then presented 'Improvement of the construction VE's incentive system relevant law and system', 'Construction VE experts and construction formation' etc. for ways to bring acceptance of the construction VE in the construction industry.

• Resources Recycling
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• v.21 no.6
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• pp.12-22
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• 2012

This study investigated a utilization technology of light burned dolomite. light burned dolomite ($CaMg(CO_3)_2$) generated in furnace (steel manufacturer) is an alternative to quick lime. Using light burned dolomite has an effect on reducing the consumption of fluorite slag MgO concentration in supersaturated solution by prolonging the life of softening effect. Armophous MgO, not containing periclase is formed by firing dolomite under $800^{\circ}C$. It has larger surface area and higher reactivity than periclase, and also shows better expansion effect than quicklime. Due to those effects, therefore, armophous MgO produced from light burned dolomite is used as an alternative expansion agent in mortar. In the experiment, characteristics of light burned dolomite were compared to those of existing expansion agents such as anhydrite and quicklime. Then, each expansion and shrinkage rates were measured over a period of about 3 months in both of 1m Jis mold at labscale and apartment mortar flooring at field scale. In the result, it was observed that light burned dolomite in mortar flooring more compensates for the expansion and shrinkage rates than the existing expansion agents, showing low expansion rate of below 0.05% and also decreases the crack.

• Archives of design research
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• v.17 no.1
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• pp.37-48
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• 2004

Keiji Kobo is a unique self-generated design research group in Japan, which was founded in 1928 when Bauhaus movement was in its peak, and which lasted ten years until the end of the Second World War, when any activity of the group became virtually impossible due to the war. With insight to see the future, the group aimed at Modern Design advocating a new spirit in architecture, and played a significant role in prosperity of Japanese Modern Design assimilating Western design trends. Pursuing of craft works for everyday life--practical furniture works--Keiji Kobo actively executed various projects to realize modern philosophy. The range of the works of this group was very large: survey, mock-up, experiment, research, exhibition, lecture, order-based sale, advertising and writing. The works of the group were oriented to serious academicism, not compromising with commercialism. Considering the peculiar political situation such as Japanese Militarism, the spirit of functionalism that the group pursued was surprisingly academical and pure. This group was relatively small and clumsy, which lasted as short as around ten years. However, strong motivation was in their seemingly quiet movements, and the influence of the group cannot be underestimated even with today's criteria. There were a number of pioneers who contributed to today's prosperity of Japan and Keiji Kobo can be estimated to be one of the pioneers in the field of design. It was found that the contemporary intellectuals hoped that the committment and activity of the group would contribute to modernization of the life quality of ordinary people. In a sense, Keiji Kobo can be estimated to be a little Japanese equivalent for Bauhaus that could not fully bloom.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.927-939
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• 2015

It appears that the rapid advance in technology has allowed to broaden the variety of rail systems technology, thereby fostering new business opportunity in rail industry. The direction of rail systems operations is mainly two fold. In one direction, long distance operations between mega cities are pursued with help of high speed trains under development. In the other case, relatively short distance operations for covering intra-city or suburban area are becoming popular. A good example of the latter case is light rail transit (LRT) systems. Due to the short distance operation, it is thus expected that both the development and operation cost for LRT systems be reduced to some extent. The cost reduction desired in there can be gained by scaling down the sizes of both the trains and stations as compared to those of normal rail systems. However, it is not well known how the LRT stations can be scaled down. The objective of this paper is to study on how to slim down the stations (particularly, the functions room) of LRT systems. To achieve the objective, an approach is studied based on a modified method of design structure matrix (DSM). Specifically, using the enhanced DSM method, an integrated architecture is developed for the functions room, in which equipments are housed to perform the functions of electricity, signaling, and communication for LRT stations. The use of the result indicates that the desired reduction can be obtained with the approach taken in the paper.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.2
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• pp.63-74
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• 2016

The purpose of this study is to expand a prospect of a few-remaining Byeolseo scenic sites of Gangwon-do(Province) through determining placeness formation, prospect characteristics, and landscape meanings of Gumi(Nine beauties) and Sipalgyung(18 scenic views) in Gumijeongsa. Gumijeongsa, which is located in a riverside of the Goljicheon(stream), a part of upstream of Namhangang, is the oldest existing Nujung architecture in the Jeongseon area. This study tried to unearth the Gumijonegsa's locational and formational characteristics through literature review and a field survey. Especially, through the field survey, this study tried to figure out the landscape meanings and contents of Gumi and Sipalgyung by Gumijeongsa's position and its prospect compositions. As a result of this study, Gumi and Sipalgyung of Gumijeongsa are variations of typical traditional culture of Gugok(Nine river bends) and Palgyung(Eight scenic views). Ja Lee, the founder, administrated Gumijeongsa as a core residence of Gugok culture. He established beautiful nine viewpoints from the building, named Gumi, and added 18 detailed landscapes(two landscapes for one beauties), instead of establishing nine river bends of the stream. The Gumi and Sipalgyung are formed by reflection of beautiful locational characteristics from the views in Gumijeongsa, thus the Gumi is the concept which is a unique variation of Gugok and Palgyung culture.