• Computers and Concrete
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• v.24 no.2
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• pp.151-158
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• 2019

The sustainable development principle of replacing natural resources with renewable material is an important research topic. In this study, waste LCD (liquid crystal display) glass powder was used to replace cement (0%, 10%, 20% and 30%) through a volumetric method using three water-binder ratios (0.47, 0.59, and 0.71) to make cement mortar. The compressive strength was tested at the ages of 7, 28, 56 and 91 days. The test results show that the compressive strength increases with age but decreases as the water-binder ratio increases. The compressive strength slightly decreases with an increase in the replacement of LCD glass powder at a curing age of 7 days. However, at a curing age of 91 days, the compressive strength is slightly greater than that for the control group (glass powder is 0%). When the water-binder ratios are 0.47, 0.59 and 0.71, the compressive strength of the various replacements increases by 1.38-1.61 times, 1.56-1.80 times and 1.45-2.20 times, respectively, during the aging process from day 7 to day 91. Furthermore, a prediction model of the compressive strength of a cement mortar with waste LCD glass powder was deduced in this study. According to the comparison between the prediction analysis values and test results, the MAPE (mean absolute percentage error) values of the compressive strength are between 2.79% and 5.29%, and less than 10%. Thus, the analytical model established in this study has a good forecasting accuracy. Therefore, the proposed model can be used as a reliable tool for assessing the design strength of cement mortar from early age test results.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.98-103
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• 2011

Photocatalysis using UV light and catalysts is an attractive low temperature and non-energy- intensive method for remediation of a wide range of chemical contaminants like chloroform (CF). Recently development of environmental friendly and sustainable catalytic systems is needed before such catalysts can be routinely applied to large-scale remediation or drinking water treatment. Titanium dioxide is a candidate material, since it is stable, highly reactive, and inexpensive. Diatoms are photosynthetic, single-celled algae that make a microscale silica shell with nano scale features. These diatoms have an ability to biologically fabricate $TiO_2$ nanoparticles into this shell in a process that parallels nanoscale silica mineralization. We cultivated diatoms, metabolically deposited titanium into the shell by using a two-stage photobioreactor and used this biogenic $TiO_2$ to this study. In this study we evaluated how effectively biogenic $TiO_2$ nanoparticles transform CF compared with chemically-synthesized $TiO_2$ nanoparticlesthe and effect of pretreatment of diatom-produced $TiO_2$ nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-$TiO_2$ particles is a factor of 3 slower than chemically-synthesized one and chloride ion production was also co-related with CF transformation, and 79~91% of CF mineralization was observed in two $TiO_2$ particles. And the period of sonication and mass transfer due to particle size, evaluated by difference of oxygen tention does not affect on the CF transformation. Based on the XRD analysis we conclude that slower CF transformation by diatom-$TiO_2$ might be due to incomplete annealing to the anatase form.

• Environmental and Resource Economics Review
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• v.30 no.2
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• pp.269-297
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• 2021

Bioplastics are attracting attention as a substitute for conventional petroleum-based plastics because they are carbon neutral and can be biodegradable. This study estimated economic and environmental impact of regulating the petroleum-based plastics industry and fostering the bioplastics industry using a Recursive Dynamic CGE Model of the Korean Economy. Results show that the regulation of the conventional plastics industry exhibits a positive environmental impact by reducing greenhouse gases and plastic waste and a negative economic impact with a decrease in GDP. Meanwhile, fostering the bioplastics industry with regulation on conventional plastics industry has similar levels of greenhouse gas and waste reduction effects when there is only regulation on the conventional plastics industry. It is also shown that expanding the production of bioplastics industry offsets existing economic losses as a form of increased GDP. If petroleum-based plastics are replaced through the expansion of bioplastics production, it can contribute to the decoupling of greenhouse gas emissions and plastic waste from economic growth.

• Fashion & Textile Research Journal
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• v.22 no.6
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• pp.853-861
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• 2020

Various types of clothing are being developed to boost thermal comfort during cold winters along with research on change of body temperature when heating is applied. There is a noticeable behavioral difference by gender when using heating panels in a cold environment; however, research on women has been insufficient. This study find a temperature range that provides sustainable thermal comfort in a low temperature environment by observing temperature and change of temperature when subjects are classified according to physical activities or cold sensitivities. For the study results, 8 women in their 20s were subjected to experiment in a low temperature environment for 75 minutes (sitting position: 30 min., running: 15 min., and sitting position: 30 min.). Subjects were asked to turn on/off the heating panel freely to analyze the range of comfortable temperature and clothing microclimate; in addition, skin temperature and heating panel temperature were measured and analyzed at 9 points. As a result, temperature at which subjects turn on and off the heating panel indicated a statistically meaningful difference between the cold sensitivity group depending on exercise or non-exercise. The range of comfortable abdomen temperature was wider than the lower back and was significantly reduced when the subject was running. The range of comfortable temperature was also largest for the heating panel temperature, microclimate, and skin temperature in suggesting that adequate adjustment will be required depending on the surrounding environment or movement of the wearer.

• Earthquakes and Structures
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• v.23 no.6
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• pp.493-502
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• 2022

In recent decades, infrastructural development has exploded, particularly in the coastal region of Saudi Arabia. The rising demand of most consumed aggregate in construction can be effectively compensated by the alternative material like scoria which lavishly exists in the western region. Scoria is characterized as lightweight aggregate beneficially used to develop lightweight concrete (LWC) - a potential alternative of normal weight concrete (NWC) ensuring reduction in the structural element's size, increase in building height, comparatively lighter foundation, etc. Hence, the goal of this study is to incorporate scoria-based structural lightweight concrete and evaluate its impact on superstructure and foundation design beside contributing to the economy of construction. Fresh, mechanical, and rheological properties of the novel LWC have been investigated. The structural analyses employ the NWC as well as LWC based structures under seismic and wind loadings. The commercial finite element package - ETABS was employed to find out the change in structural responses and foundations. The cost estimation and SWOT analysis for superstructure and foundation have also been carried out. It was revealed that the developed LWC enabled a more flexible structural design. Notable reduction in the steel and concrete prices of LWC might be possible in the low-rise building. It is postulated that the cost-effective and eco-friendly LWC will promote the usage of scoria as an effective alternative in Saudi Arabia and GCC countries for structurally viable LWC construction.

• Journal of the Korean institute of surface engineering
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• v.55 no.3
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• pp.180-186
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• 2022

The production of hydrogen via water electrolysis (i.e., green hydrogen) using renewable energy is key to the development of a sustainable society. However, most current electrocatalysts are based on expensive precious metals and require the use of highly purified water in the electrolyte. We demonstrated the preparation of a non-precious metal catalyst based on CuCo₂O₄ (CCO) via simple electrodeposition. Further, an optimization process for electrodeposition potential, solution concentration and electrodeposition method was develop for a catalyst-substrate integrated electrode, which indicated the highly electrocatalytic performance of the material in electrochemical tests and when applied to an anion exchange membrane water electrolyzer.

• Korean Journal of Organic Agriculture
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• v.30 no.3
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• pp.409-422
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• 2022

Southern blight caused by Sclerotium rolfsii is a serious soilborne disease in economically important crops including pepper. In this study, we conducted a selection of antagonistic bacterial strains and organic materials to biologically control the disease. Out of 39 strains isolated from soils at Jinju in Korea, strain JJ2-01 showed the highest mycelial growth inhibition; garlic oil among various organic materials significantly reduced disease incidence and severity. When a combination of strain JJ2-01 and garlic oil, or each was drenched into the pepper plants, combined treatment and garlic oil significantly suppressed the disease development, however, acid phosphatase activity in garlic oil-treated plants decreased. In the case of combined treatment, the soil activities did not affect by treatment, while soil urease activity was significantly increased by the combined treatment. Therefore, given soil quality and health for sustainable agriculture, the combination of strain JJ2-01 and garlic acid was an effective application for environmental-friendly control of Southern blight in pepper plants.

• The Research Journal of the Costume Culture
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• v.30 no.4
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• pp.513-528
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• 2022

The purpose of this study is to understand the concept of zero-waste design and to apply Sophia Vyzoviti's folding techniques to develop a zero-waste fashion design method that contributes to sustainable fashion design. In this study, we explore the method and characteristics of zero-waste fashion design based on the concept of folding described in Sophia Vyzoviti's book on folding techniques. Using the autonomy of Sophia Vyzoviti's folding technique, four changeable folding fashion designs were developed and produced, demonstrating zero-waste fashion design. The results were as follows. First, the development of fashion designs using Sophia Vyzoviti's folding techniques enabled the development and production of free and creative zero-waste fashion designs that were three-dimensional, continuous, fluid, and full of potential. Second, the production of zero-waste patterns was further developed into a transformable fashion design that can be used with geometric patterns. These folding techniques produced a fashion design method that could transform one piece of clothing, demonstration the potential for maintenance of creativity using a zero-waste design based on these folding techniques. Third, the double-faced fabric, Neoprene, was chosen as an appropriate material as it emphasizes the depth of folding with application of two colors and its cotton/polyester blend that is suitable for folding.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1226-1236
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• 2022

Because students majoring in construction-related fields must develop a broad repository of knowledge and skills, effective transferal of these is the primary focus of most academic programs. While inculcation of this body of knowledge is certainly critical, actual construction projects are complicated ventures that involve levels of risk and uncertainty, such as resistant neighboring communities, unforeseen weather conditions, escalating material costs, labor shortages and strikes, accidents on jobsites, challenges with emerging forms of technology, etc. Learning how to develop a level of discernment about potential ways to handle such uncertainty often takes years of costly trial-and-error in the proverbial "school of hard knocks." There is therefore a need to proactively expedite the development of a sharpened intuition when making decisions. The AGC Education and Research Foundation case study committee was formed to address this need. Since its inception in 2011, 14 freely downloadable case studies have thus far been jointly developed by an academics and industry practitioners to help educators elicit varied responses from students about potential ways to respond when facing an actual project dilemma. AGC case studies are typically designed to focus on a particular concern and topics have thus far included: ethics, site logistics planning, financial management, prefabrication and modularization, safety, lean practices, preconstruction planning, subcontractor management, collaborative teamwork, sustainable construction, mobile technology, and building information modeling (BIM). This session will include an overview of the history and intent of the AGC case study program, as well as lively interactive demonstrations and discussions on how case studies can be used both by educators within a typical academic setting, as well as by industry practitioners seeking a novel tool for their in-house training programs.

• Elastomers and Composites
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• v.58 no.1
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• pp.32-43
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• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.