• Advances in concrete construction
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• v.2 no.2
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• pp.145-162
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• 2014

In this study, the fracture toughness $K_{IC}$ of high performance concrete (HPC) was determined by conducting three-point bending tests on eighty notched HPC beams of $500mm{\times}100mm{\times}100mm$ at high temperatures up to $450^{\circ}C$ (hot) and in cooled-down states (cold). When the concrete beams exposed to high temperatures for 16 hours, both thermal and hygric equilibriums were generally achieved. $K_{IC}$ for the hot concrete sustained a monotonic decrease tendency with the increasing temperature, with a sudden drop at $105^{\circ}C$. For the cold concrete, $K_{IC}$ sustained a two-stage decrease trend, dropping slowly with the heating temperature up to $150^{\circ}C$ and rapidly thereafter. The fracture energy-based fracture toughness $K_{IC}$' was found to follow similar decrease trends with the heating temperature. The weight loss, the fracture energy and the modulus of rapture were also evaluated.

• Advances in concrete construction
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• v.2 no.2
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• pp.125-144
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• 2014

The development in roller compacted concrete (RCC) is replacing the conventionally vibrated concrete (CVC) for faster construction of dam during last three-four decades. Notwithstanding, there have been relatively less works reported on the utilization of RCC in dam constructions, especially the dams having considerable height. Further, the Ghatgar dam was the only dam in the tropical country like India constructed using the technology of RCC until two years back. However, with the completion of 102.4 m high Middle Vaitarana Dam (MVD), owned by Muncipal Corporation of Greater Mumbai (MCGM), India, has become the first largest roller compacted concrete dam. The paper traces step by step aspects of the mix design of RCC in respect of the afore-mentioned project besides the construction aspects; and also, demonstrates as to how 12.15 lacs cubic meter of roller compacted concrete was placed within the record duration of 15.2 months, thus, rendering the MVD as the ninth fastest RCC dam in the world. The paper also discusses the various mix proportioning, quality control, constructional features and instrumentation with respect to the high RCC dam such as Middle Vaitarana.

• Advances in concrete construction
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• v.6 no.3
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• pp.297-309
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• 2018

The objective of this study was to evaluate the influence of silica fume (SF) on the hydration heat and compressive strength of concrete. Portland cement with w/(c+sf) ratios varying between 0.25 to 0.45 was substituted by 10%, 20% and 30% of SF by mass. A superplasticizer was used to maintain a fluid consistency of the concrete. The heat of hydration was monitored continuously by a semi-adiabatic calorimetric method for 10 days at $20^{\circ}C$. Compressive strengths are tested for each mixture until age of 180 days. The results show that silica fume considerably influences the evolution and the ultimate values of the compressive strengths as well as the hydration heat especially for 10% rate. The w/b ratio has a considerable effect where its decrease modifies compressive strength and hydration heat more than silica fume. The correlation of the obtained results allows deducing of ultimate properties as well as the ages to reach half of their values. The correlation coefficients are close to unity and reflect the judicious choice of these relationships to be used to predict compressive strength and hydration heat.

• Advances in concrete construction
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• v.6 no.3
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• pp.311-322
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• 2018

This paper presents an experimental investigation on the performance of concrete with and without glass powder (GP) subjected to elevated temperatures. Mechanical and physicochemical properties of concretes were studied at both ambient and high temperatures. One of the major environmental concerns is disposal or recycling of the waste materials. However, a high volume of the industrial production has generated a considerable amount of waste materials which have a number of adverse impacts on the environment. Further, use of glass or by-products in concrete production has advantages for improving some or all of the concrete properties. The economic incentives and environmental benefits in terms of reduced carbon footprint are also the reason for using wastes in concrete. The occurrence of spalling, compressive strength, mass loss, chemical composition, crystalline phase, and thermal analysis of CPG before and after exposure to various temperatures (20, 200, 400, and $600^{\circ}C$) were comprehensively investigated. The results indicated that, the critical temperature range of CPG was between $400^{\circ}C$ and $600^{\circ}C$.

• Architectural research
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• v.19 no.3
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• pp.53-61
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• 2017

This study aims to understand and analyze the social recognition and debate shown during the progress of the Asian Culture Complex (ACC) public project as well as the environmental evaluation performed by provincial community members. A 30-question survey based on a Likert scale was conducted with 150 experts. The study showed, first, that despite controversies over landmarks and historical locations, the quality of the architect's first draft was considered fairly high. However, vibrant landmarks were greatly desired. Furthermore, respondents reported conflicting recognitions of the same concept, which were defined differently depending on the terms and concepts used by the architect. Second, historical locations were considered important. The architects' final design was modified based on quality and in response to social pressure, resulting in the partial retention of the provincial government annex building. Although the first draft was considered to be of high quality, the modified plan was considered even better than the original design, revealing the 2-fold characteristics of the identical phenomenon in the environmental evaluation. Third, many groups held opinions that were balanced between the architects' originality and the value of community-based recognition; hence, the social inclination and evaluation of the project differed across the public.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.3
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• pp.307-314
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• 1996

The rate of evolution of ethylent by tomato plants was rapidly increased by ozone fumigation. In the present study, the mechanism of ethylent evolution by ozone was investigated in experiments with aminoethoxyvinylglycine (AVG) and tiron, which inhibit the formation of ethylene and peroxidation of lipids, respectively. Pretreatment with AVG significantly inhibited the ozone-induced ethylent evolution, but the treatment of plants with tiron did not inhibit. These results indicate that the induction of the evolution of ethylene by ozone involves the pathway via aminocyclopropane-1-carboxylate (ACC), while not released as a result of the peroxidation of lipids. Ozone-induced ethylent evolution was greater in dar- than light-incubated, intact tomato plants. The difference between dark- and light-ethylene evolution was examined with diuron, an inhibitor of photosynthetic electron transport. The inhibitor treatment promoted ethylent evolution. These results suggest that ethylent retention and metabolism in plants were regulated by internal $CO_2$ levels which, in turn, were controlled in large part by photosynthesis. Thus, ethylene was retained in illuminated leaf tissue under low intenal $CO_2$ concentration which may develop in a sealed container without exogenously supplied $CO_2$.

• KIEAE Journal
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• v.16 no.1
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• pp.103-110
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• 2016

Purpose: This study suggests the multi-purposed emotional space that is one of the alternatives to reuse idle spaces in the city. Because human who is living in modern society begins pursue new contents and leisurely life all the time and live toward the period of high emotion with personal characteristics, architectural industry also need to change its planning and design to satisfy contemporary man and to adjust rapid social mobility. Method: For this study, the buildings where are located near Asia Cultural Complex (ACC) and leaved as idle spaces now that is used for important facilities are used to apply the multi-purposed emotional Space. Essential methodology and terminology were examined to estimate and construct the multi-purposed emotional space. Result: The multi-purposed emotional space provides that people aggressively request subjects to satisfy their emotional attractiveness as well as comforts and pleasures beyond the functional basic requirements in space. On the other words, it can be regarded as limited context to physical space responsive to social and environmental changes for the surrounding, and may maximize user experiences. Since emotions tend to be abstract and subjective while architectural space has pretty physical properties, this study attempts to integrate contrastive properties between emotional and architectural spaces to make a real object.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.357-359
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• 2000

This paper is to introduce the R&D project called "Improvement of Automatic Gene-ration Control Related Systems for New Energy Management system". The principal objective of this project is to demonstrate AGC operation capabilities that are suitable to new EMS environment and to show the validity of Set-Point Control Method. A number of developments and enhancements have been made to the generator's Remote Terminal Unit in which new ASTC is being developed and installed. The so-called ACC Signal Transfer Card(ASTC) will include RTU's Set-Point Control capabilities. It is expected that over next few months both RTU & DCS software modifications will be given and a relatively new Set-Point Control Method will be chosen instead of those from more conventional method, pulse control method.

• Journal of the Korean Wood Science and Technology
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• v.20 no.1
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• pp.15-22
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• 1992

This study was performed to investigate the corrosion of metal fasteners in waterborne preservative-treated wood. Of all the metal tested, steel exhibited the greatest amount of corrosion across all preservatives and exposure conditions whereas stainless steel was totally inert. Galvanized steel corroded at a much lower rate compared to steel and the corrosion of brass was negligible. Among the preservatives, CCA-Type B was the most corrosive system tested. The sequence for the average corrosivity across all metals was: CCA-type B>CCA-Type C${\geq}$ACC${\geq}$CCA-Type A. Across all metals and retentions the salt formulations were more corrosive than the oxide and the corrosion was increased with the increse in the amount of preservative loadings. The amount of corrosion was also increased with the increase in exposure relative humidity (RH) across all metals and presevatives However, at the 60% RH exposure condition, the corrosion of metals was very negligible. Consequently, it can be concluded that across all metals oxide-type preservatives should be used to prevent the corrosion problem of metal fasteners in contact with treated wood and the use of steel nail preservative-treated wood should be avoided without distinction of end-use location, i.e., exterior or interior, and the use of stainless steel or at least brass nail in damp exterior condition was strongly recommended.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.58-66
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• 2011

Arsenic pollution is a serious global concern which affects all life forms. Being a toxic metalloid, the continued search for appropriate technologies for its remediation is needed. Phytoremediation, the use of green plants, is not only a low cost but also an environmentally friendly approach for metal uptake and stabilization. However, its application is limited by slow plant growth which is further aggravated by the phytotoxic effect of the pollutant. Attempts to address these constraints were done by exploiting plant-microbe interactions which offers more advantages for phytoremediation. Several bacterial mechanisms that can increase the efficiency of phytoremediation of As are nitrogen fixation, phosphate solubilization, siderophore production, ACC deaminase activity and growth regulator production. Many have been reported for other metals, but few for arsenic. This mini-review attempts to present what has been done so far in exploring plants and their rhizosphere microbiota and some genetic manipulations to increase the efficiency of arsenic soil phytoremediation.