• Computers and Concrete
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• v.13 no.3
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• pp.325-342
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• 2014

The use of lightweight aggregate (LWA) instead of ordinary aggregate may make lightweight aggregate concrete, which possesses many advantages such as lightweight, lower thermal conductivity, and better fire and seismic resistance. Recently the developments of LWA have been focused on using industrial wastes as raw materials to reduce the use of limited natural resources. In view of this, the intent of this study was to apply Taguchi optimization technique in determining process condition for producing synthetic LWA by incorporating waste thin film transition liquid crystal displays (TFT-LCD) glass powder with reservoir sediments. In the study the waste TFT-LCD glass cullet was used as an additive. It was incorporated with reservoir sediments to produce LWA. Taguchi method with an orthogonal array L16(45) and five controllable 4-level factors (i.e., cullet content, preheat temperature, preheat time, sintering temperature, and sintering time) was adopted. Then, in order to optimize the selected parameters, the analysis of variance method was used to explore the effects of the experimental factors on the performances (particle density, water absorption, bloating ratio, and loss of ignition) of the produced LWA. The results showed that it is possible to produce high performance LWA by incorporating waste TFT-LCD glass cullet with reservoir sediments. Moreover, Taguchi method is a promising approach for optimizing process condition of synthetic LWA using recycled glass cullet and reservoir sediments and it significantly reduces the number of tests.

• Geomechanics and Engineering
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• v.8 no.1
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• pp.53-66
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• 2015

Plastic wastes, particularly polyethylene terephthalate (PET) generated from used bottled water constitute a worldwide environmental issue. Reusing the PET waste for geotechnical applications not only reduces environmental burdens of handling the waste, but also improves inherent engineering properties of soil. This paper investigated factors affecting shear strength improvement of PET-mixed residual soil. Four variables were considered: (i) plastic content; (ii) plastic slenderness ratio; (iii) plastic size; and (iv) soil particle size. A series of unconfined compression tests were performed to determine the optimum configurations for promoting the shear strength improvement. The results showed that the optimum slenderness ratio and PET content for shear strength improvement were 1:3 and 1.5%, respectively. Large PET pieces (i.e., $1.0cm^2$) were favorable for fine-grained residual soil, while small PET pieces (i.e., $0.5cm^2$) were favorable for coarse-grained residual soil. Higher shear strength improvement was obtained for PET-mixed coarse-grained residual soil (148%) than fine-grained residual soils (117%). The orientation of plastic pieces in soil and frictional resistance developed between soil particles and PET surface are two important factors affecting the shear strength performance of PET-mixed soil.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.2
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• pp.209-215
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• 2022

This study aims to analyze the livelihood resources and income diversification of informal recyclers in the Mekong River Delta (MRD). The multiple linear regression model was applied to determine income diversification and total household income with the sustainable livelihood analysis framework developed by the United Kingdom Department for International Development (2000), including human resources, physical resources, natural resources, financial resources, and social resources. The results indicated that up to 25% of itinerant waste buyers worked on average more than 7.3 hours/day, which was higher than the urban near-poor level regulated by the Vietnam government. The results of the regression model revealed that total households' income was affected by the factors of health status, gender, urban location type 1, the amount of potential savings, and informal credit participation, while the factors of health status, urban location, the amount of potential savings, and informal credit participation have the effect of diversifying farm household income. Thus, if the informal waste recycling sector is supported and regulated by proper government management, it will not only help poor households diversify their income, but it will also help poor households diversify their income, particularly women's income, which is vulnerable and lower than male income in the MRD.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.674-680
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• 2022

In the present study, radiation shielding and protection ability of prepared Flyash-lime-Gypsum (FaLG) bricks has been studied in terms of energy exposure build up factors and dose parameters. The energy exposure build up factors of Flyash-lime-Gypsum (FaLG) bricks have been calculated for the energy range of 0.015 MeV-15 MeV and for penetration depth upto 40 mfp directly using a new and simplified Piecewise Linear Spline Interpolation Method (PLSIM). In this new method, the calculations of G.P fitting parameters are not required. The verification and accuracy of this new method has been checked by comparing the results of exposure build up factor for NBS concrete calculated using present method with the results obtained by using G.P fitting method. Further, the relative dose distribution and reduced exposure dose rate for various radioactive isotopes without any shielding material and with Flyash-lime-Gypsum (FaLG) bricks have been calculated in the energy range of 59.59-1332 keV. On the basis of the obtained results, it has been reported that the prepared Flyash-lime-Gypsum (FaLG) bricks possess satisfactory radiation shielding properties and can be used as environmentally safe storage facilities for low level nuclear waste.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2875-2878
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• 2011

The wooden sleeper has been used at the railway track. Recently the concrete sleeper is pushing the wooden sleeper out, but huge amount of waste wooden sleepers are discharged every year. Due to the contaminant of waste wooden sleeper, its disposal is very difficult. Commonly a wood preservative such as creosote is used in the manufacturing process and it becomes major contaminant after use. And the wooden sleeper is contaminated by diesel from locomotives and lubricant oil from the maintenance of railway turnout. Currently the limitary disposal methods can be used because of high toxicity of waste wooden sleeper. Therefore the preliminary study on thermal-extraction of contaminants such as creosote, diesel and lubricant oil from waste wooden sleeper was conducted and the effects of factors were investigated.

• Journal of Families and Better Life
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• v.16 no.4
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• pp.197-220
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• 1998

This study is conducted to examine the ways to reduce the garbage amount by effective recycling food wastes in the cooking. The data is collected from 864 housewives who live in Seoul/Sungnam/Choongju by using questionnaires from 24 November 1997 to 5 January 1998. The results are as follows; The level of their needs of reusing food wastes in the cooking is high but the level of their participation and its satisfaction to reuse housewives is low. Especially they take part in reusing the garbage in pre-treatment less than edibile plate wastes. These factors result from lacking of their consciousness and knowledge of methods to reuse food wastes. Therefore it is said that consumer should make an effort themselves to participate in reusing food waste researcher should search the way to efficiently reuse the food waste and government should found the policy to provide information and education program for reusing food waste. The more seriously they perceive food waste reuse the mo e they want the way to accelerate food waste reuse by consumer researcher and government.

• Journal of the Korean Geotechnical Society
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• v.31 no.4
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• pp.5-12
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• 2015

The construction of waste landfill sites has been increased due to recent expansion of various waste. Geotextiles are widely used for the purpose of reinforcement and protection of waste inside the landfill. Geotextile affects the shear behavior of waste landfill which forms the contact surface with soil. In this study, the effect of acidic and alkaline components in leachate has been analyzed through the laboratory experiment on the shear stress reduction of the contact surface of ground-geotextile under the cyclic load. For this purpose, a dynamic contact surface shear tester has been manufactured, and cyclic simple shear tests have been performed using geotextile and soil specimen which were immersed in chemical solutions for 60 and 840 days, respectively. Based on the Disturbed State Concept, the characteristics of shear stress on the contact surface of ground-geotextile due to chemical factors have been identified by the disturbance function.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2019.10a
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• pp.134-134
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• 2019

Utilization of organic waste as a renewable energy source is promising for sustainability and mitigation of climate change. Pyrolysis converts organic waste to gas, oil, and biochar by incomplete biomass combustion. Biochar is widely used as a soil conditioner and adsorbent. Biochar adsorbs/desorbs metals and ions depending on the soil environment and condition to act as a nutrient buffer in soils. Biochar is also regarded as a carbon storage by fixation of organic carbon. Phosphorus (P) and nitrogen (N) are strictly controlled in many wastewater treatment plants because it causes eutrophication in water bodies. P and N is removed by biological and chemical methods in wastewater treatment plants and transferred to sludge for disposal. On the other hand, P is an irreplaceable essential element for all living organisms and its resource (phosphate rock) is estimated about 100 years of economical mining. Therefore, P and N recovery from waste and wastewater is a critical issue for sustainable human society. For the purpose, intensive researches have been carried out to remove and recover P and N from waste and wastewater. Previous studies have shown that biochars can adsorb and desorbed phosphates implying that biochars could be a complementary fertilizer. However, most of the conventional biochar have limited capacity to adsorb phosphates and nitrate. Recent studies have focused on biochar impregnated with metal salts to improve phosphates and nitrate adsorption by synthesizing biochars with novel structures and surface properties. Metal salts and metal oxides have been used for the surface modification of biochars. If P removal is the only concern, P adsorption kinetics and capacity are the only important factors. If both of P and N removal and the application of recovery are concerned, however, P and N desorption characteristics and bioavailability are also critical factors to be considered. Most of the researches on impregnated biochars have focused on P removal efficiency and kinetics. In this study, coffee waste is thermally treated to produce biochar and it was impregnated with Mg/Al to enhance phosphates and nitrate adsorption/desorption and P bioavailability to increase its value as a fertilizer. Kinetics of phosphates and nitrate adsorption/desorption and bioavailability analysis were carried out to estimate its potential as a P and N removal adsorbent in wasewater and a fertilizer in soil.

• Journal of Environmental Health Sciences
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• v.15 no.2
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• pp.51-58
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• 1989

In order to estimate unit loading factors of N, and P for controlling eutrophication of Youngsan lake. This study was performed in 4 kinds of pollutant sources from domestic sewage, industrial waste water, livestock stall waste water and drainage of agricultural area during the period from april to october 1988. These results were as follows: 1. The sewage flow for domestic waste water was 191.2 l/capita, day and that of the gray and toilet waste water among the domestic waste water were shown 152.9 l/capita, day(80%) and 38.3 l/capita, day(20%), respectively. 2. The unit loading factor total nitrogen(T-N) for domestic waste water was 7.582g/capita, day, and that of the gray and toilet waste water among the domestic waste water were 1.826g/ capita, day(24.1%) and 5.756g/capita, day(75.9%), respectively. The other hand, the unit loading factors of total phosphorus(T-P) for domestic waste water was 0.925g/capita, day, and that of gray and toilet waste water among the domestic waste water were 0.470g/capita, day(50.8%) and 0.455g/capita, day(49.2%), respectively. 3. In offering Price per million won, the T-P loading factor for drinking manufacture, confectionery manufacture, beer-manufacture and fibre manufacture in the industrial pollutant sources estimate to be 0.350g/day, 0.099g/day, 32.351g/day and 1.536g/day, while T-N loading factor about them in the industrial pollutant sources estimate to be 4.117g/day, 2.414g/day, 106.726g/day and 60.504g/day, respectively. 4. The T-P loading factor according to wash-water of milch cow and pig were 6.735g/day and 18.526g/day, in case of T-N they were 42.397g/day and 27.226g/day, respectively. 5. The T-P loading factor for pollutants drainage in the Paddy fields, fields and forests area were 0.082g/are, day, 0.014g/are, day and 0.002g/are, day, and the T-N loading factor were 0.309g/are, day, 0.158g/are, day and 0.064g/are, day, respectively. The diffrent of the loading factor for pollutants discharges in the agricultural area were resulted from the rainful intensity, the rainful, the amount of fertilization manure, and etc.

• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.113-121
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• 1997

LHR(Landfill Hazard Ranking Model) was developed for assessing the relative hazard of landfills by using the method of value-structured approach. LHR consists of combining a multiattribute decision-making method with a qualitative risk assessment approach. A pairwise comparision method was applied to determine weights of landfill factors related. To prove the validity of weights allocation of landfill hazard evaluation factors, sensitivity analysis was applied. Firstly, the impact on landfill hazard score according to variations of weights of landfill hazard factors was analyzed. Secondly, the impact on landfill hazard score according to conditions change of landfill hazard factors was analyzed. As a result of sensitivity analysis, LHR composite scores are largely influenced by some factors following sequential order such as waste volume, proximity to sensitive environments, containment facilities, distance from drinking water supplies, and waste toxicity. The relative order of landfill hazard evaluated by LHR is not influenced by the weights change of individual factors. Therefore, LHR seems to be a credible model to determine priorities of landfill remediation based on the vulnerability of water resources.