• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.105-112
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• 2005

Stabilizing and rousing sludge water generated from washing truck mixer and batcher plant can resolve inconsistency in quality and improve strength, therefore it is essential to review how to utilize it. This research conducted experiments and studied on solids of sludge water to find out the types of stabilizing agents available in conditions of producing ready mixed concretes in Korea. The result showed that oxy carboxylic acid retarder dedicated for stabilizing sludge water was most effective in decreasing solid. However, the setting time of cement paste was retarded due to surplus reactants, but it did not impede application of ready mixed concretes. When we left the sludge water mixed with stabilizing agent, it has been noted that initial retard effect recovered to the level using just service water in 7${\~}$8 days and that it is effective to use stabilized sludge water in 2${\~}$3 days. On the other hand, saccharic type super retarding agent was also outstanding in applicability by showing similar effect. The sludge water stabilizing agents currently marketed depend on imports, therefore it is necessary to locally manufacture usable stabilizing agents and to review its usability with multi-dimensional view.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.350-355
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• 2013

Little information is available for emission pathway even if HFC-134a that is known as one of the major greenhouse gases has been broadly used in Korea. This paper attempts to clarify the emission characteristics of HFC-134a used for refrigerant of cold drinking vending machines (CDVMs) at the use- and disposal-phase. We measured the residual amounts in the scrap CDVMs of 47 by applying commercial recover for refrigerant. The first-order kinetic model was introduced and the emission rate would be proportional to the remaining quantity of refrigerant. The emission factor at the use-phase was determined indirectly to be $6.9{\pm}0.7$ %/yr within a confidence interval of 95%, using information on residual amount and elapsed operation time at the disposal point. Correspondingly, the annual emission rate of HFC-134a per CDVM was determined to be 11.6 g. The average residual rate of HFC-134a in scrap CDVMs was assessed to be $62.5{\pm}2.2%$, leading to a potential emission amount of 144.8 g per scrap CDVM. The chemical compositions of refrigerants from scrap passenger vehicles are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap passenger vehicles could be reused. During the recovering process of refrigerant, the recovered refrigerant was contaminated by compressor lubricant that accounted for about 30% in weight. It is necessary to separate the refrigerant from the recovered material contaminated by lubricant for recycling and reuse the refrigerant.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.101-109
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• 2009

This CW(Construction wastes) are increasing as construction industry is growing, so many countries make efforts to recycle CW. Korea also made a stipulation for recycling CW. But the main content of this stipulation is for using recycled aggregates. Advanced countries try to increase reuse rate of not only recycled aggregate but also other kinds of wastes. So they are adopting SDM(separating dismantlement) method and we are also planning to make the system for SDM. This study is about SDM analysis through construction field investigation and difference analysis between SDM and UDM comparing predictive amount by UDM with real generated amount by SDM. First, the generated amount of construction wastes by SDM is more than estimated amount by UDM, and mixed waste was specially reduced more than UDM. The warehouse is easier than the office building to applicate SDM. But still there is no manual for SDM in the site, so establishment of SDM is demanded.

• Journal of Venture Innovation
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• v.6 no.4
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• pp.63-81
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• 2023

The purpose of this study was to utilize the Photovoice qualitative research method targeting university students. Through this method, we aimed to understand the perceptions of environmental issues, environmental barriers, and eco-friendly behaviors among university students. By employing the Photovoice methodology, we sought to share the perspectives of university students on eco-friendly behaviors, explore the motivations and manifestations of these behaviors, and reflect on their significance. The ultimate goal was to provide practical suggestions for fostering eco-friendly behaviors through an in-depth examination of the visual narratives and reflections of university students. Under the overarching theme of the environment, participants were given the opportunity to individually select and explore three specific sub-themes: 'My Concept of the Environment,' 'Environmental Barriers in My Life,' and 'My Eco-friendly Behaviors.' Participants engaged in the process of capturing photographs from their daily lives related to each theme, expressing their thoughts and perspectives through the selected images. Subsequently, they shared and discussed their insights, actively listening to the opinions of others in the group. The results of this study revealed several key findings. Firstly, participants assigned meaning to the photographs they selected by directly capturing aspects related to the environment, such as 'waste,' 'discomfort,' 'fine dust=environmental pollution,' and 'indifference.' Secondly, participants attributed meaning to the selected photographs related to environmental barriers, associating them with concepts like 'invisibility,' 'apathy,' 'social stigma,' 'inefficiency,' and 'compulsion.' Lastly, participants ascribed significance to photographs selected in the context of eco-friendly behaviors, with themes like 'recycling,' 'energy conservation,' 'reuse,' and 'reducing the use of disposable items.' Based on these research findings, the confirmation of the V-A-B (Values-Attitudes-Behavior) model was established. It was observed that consumers structure a hierarchical relationship between their personal values, attitudes, and behaviors. The study also identified clear impediments in consumers' daily lives hindering the practice of eco-friendly behaviors. In light of this, the research highlighted the need for strategies to address the discomfort or inconvenience associated with implementing environmentally friendly consumer behaviors. The implications of the study suggest that interventions or solutions are necessary to alleviate barriers and promote a more seamless integration of eco-friendly practices into consumers' daily routines.