• Clean Technology
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• v.15 no.3
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• pp.186-193
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• 2009

The characteristics of product materials obtained from thermal degradation of low-qualify pyrolytic oil were investigated in this study. The reactants were produced by pyrolysis of mixed plastic waste with film type in a commercial rotary kiln reaction system. The properties of reactants were measured by elemental analysis, calorimetry analysis and SIMDIST analyst. The result of degradation experiments with different reaction temperature programs was discussed through product yields, cumulative yields and production rates of oil products. The multi-step reaction temperature program resulted in higher yields of product oils and lower yields of residues than one-step reaction temperature program. The product characteristics such as production yield and the rate of oil products etc. were influenced by reaction temperature program in the continuous thermal degradation.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.610-626
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• 2020

Objectives: This study aims to investigate the concept of microplastics and their occurrence, transport, biological effects, and management methods in the ocean. Methods: I reviewed articles on microplastics in the ocean by using the Google Scholar database. Results: Plastic litter has been reported as a ubiquitous pollutant in the ocean due to the extensive consumption of plastics and the mismanagement of plastic wastes. Microplastics are generally defined as synthetic polymer particles <5 mm in size. Microplastics generated from the degradation of plastic litter are currently a serious global concern since they spread easily all over the ocean, transfer to different tissues inside contaminated animals, and even across different trophic levels inside the food web. An additional concern is the ability of microplastics to adsorb organic and inorganic pollutants and subsequently release them into the ocean. Thus, alternatives to reduce microplastics in the ocean are discussed. Conclusions: This paper summarizes the concept of microplastics and their behavior in the ocean and suggests management methods for microplastics in support of a cleaner ocean.

• Resources Recycling
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• v.11 no.3
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• pp.37-45
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• 2002

Triboelectrostatic Separation procese is a technology that different particles charged after contact and rubbing different materials are separated in an electric field. At this time, charged polarity of different materials depends on their own work function. Therefore this study discovers work functions of various plastics and determines charging characteristics for the specific optimum operation condition. The experiment is conducted with two sample sets composed of various different plastics. Each sample is charged by contact and rubbing different materials. Surface charge of charged particles is measured by Faraday Cage. The specific work function of an each plastic is driven by measured charging amount and charged particles are separated in a certain electric field ($\pm$20 kV). At last, the relationship between charging amount and separation efficiency is induced by the separation experiment.

• Journal of Industrial Technology
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• v.17
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• pp.37-42
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• 1997

Generation and physico-chemical characteristics of municipal solid wastes are very important for sanitary management. However, that has not been investigated so far especially in chunchon. And so, we tried to examine many things in detail. It was resulted that density was $90{\sim}94kg/m^3$ in school and office zone and $290{\sim}298kg/m^3$ in apartment and market place. The compositional weight fraction was food, 40~54%, paper, 14~18%, vinyl and prastic, 14~20% in house zone and market place and paper, 42~70% in school and office zone. Moisture was estimated to be 54~57% in independent house zone, apartment and market place and 11~23% in school and office zone. And three composition was water content, 44.1%, incineration particle, 11.2%, volatile parts, 44.7% in respectively. That is because of seasonal effects and regional chracteristics. In the results of chemical composition and caloric value analysis, carbon(C) was 80% in vinyl and plastic and oxygen(O) was 54.4% in paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.135-141
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• 1989

Blast furnace slag presents coarse surface for microbes to grow on and high calcium and magnesium contents to neutralize acid to be produced during anaerobic digestion. Also, slag contains aluminum and iron oxides which would promote biological flocculation, and minerals which would stimulate microbial growth. Acid wastes like dairy waste, carbohydrate waste, sanitary landfill leachate and molases wastes were applied without neutralization to laboratory reactors to examine the applicability of blast furnace slag as media. The study results indicated slag media was effective to neutralize pH and maintain microbial population in the system. Particularly, COD removal efficiency was greater than those from plastic media operations treating dairy waste at higher loading rates.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1805-1815
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• 2019

While nickel-based alloys have been widely used for power plants due to corrosion resistance and good mechanical properties, during the last couple of decades, failures of nuclear components increased gradually. One of main degradation mechanisms was primary water stress corrosion cracking at dissimilar metal welds of piping and reactor head penetrations. In this context, precise estimation of welding effects became an important issue for ensuring reliability of them. The present study deals with a series of finite element analyses and crack growth rate evaluation of Alloys 690/152. Firstly, variation of residual stresses and equivalent plastic strains was simulated taking into account welding of a cylindrical block. Subsequently, extraction and pre-cracking of compact tension (CT) specimens were considered from different locations of the block. Finally, crack growth curves of the alloys and heat affected zone were developed based on analyses results combined with experimental data in references. Characteristics of crack growth behaviors were also discussed in relation to mechanical and fracture parameters.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.101-111
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• 2009

In this study, the physico-chemical characteristics of municipal solid waste (MWS) which was treated in gangwon area were investigated. It is necessary to measure the characteristics of municipal solid waste for build a waste treatment and RDF facility and for data-base and total managing of the landfill. It was found that the average density of solid wastes is in the range of $101.8{\sim}199.8kg/m^3$. This MSW was composed of 30.7% of food wastes, 36.3% of papers, 15.8% of plastics & vinyls, 1.9% of textiles, 3.2% of wood and 1.5% of rubber & leathers respectively. Most of MSW are composed of food, paper and plastic waste and the combustible waste is more than 90%. For three components, moisture is 44.6%, combustible component is 47.7% and ash is 7.7% respectively. The chemical elements are carbon, oxygen, and hydrogen on the dry basis of wastes. The low heating value of the MSW measured by calorimeter was obtained as 2,631 kcal/kg, and the high heating value of the MSW was obtained as 3,310 kcal/kg.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.65-74
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• 2008

In this study, the composition and physico-chemical characteristics of municipal solid waste (MWS) which was treated in four different area were investigated. It is necessary to measure the characteristics of MSW to build a waste treatment and Refuse Derived Fuel (RDF) facility, the data-base and total managing of the landfill. It was found that the average density of solid wastes is in the range of $78.15-199.8kg/m^3$. This MSW was composed of 8.87% of food wastes, 38.8% of papers, 34.12% of plastics & vinyls, 7.16% of textiles, 0.96% of wood, 1.3% of rubber & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and more than 94% was combustible waste. For three components, moisture is 17.38%, combustible component is 69.03% and ash is 6.24%. The chemical element has the high order of carbon, oxygen, hydrogen on the dry basis of wastes. And the low heating value of the MSW which is measured by calorimeter is calculated as 2973.8 kcal/kg and high heating value of the MSW is calculated as 5209.94 kcal/kg.

• Resources Recycling
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• v.18 no.1
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• pp.13-21
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• 2009

A research on material separation of EVA and PET mixture plastic waste using a triboelectrostatic separator has been carried out. It was found that PP was the best charging material to give the highest charge on the surface of EVA and PET mixture plastics with an opposite polarity. Therefore, a charger of pipe line type using PP material was manufactured for separation of EVA and PET mixture plastic waste. At optimum test conditions that used PP cyclone charger developed in this study, we could separate out PET with a glade of 98.7% and a recovery of 89.7%.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.40-55
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• 2005

This study was carried out to discuss the feasibility of wood and plastic wastes as the raw materials for wood particle-plastic composites. For this purpose, composites were manufactured from coarse and fine wood particles and polypropylene fibers by nonwoven web process. And the effect of wood particle size on the performance of the composites were analyzed according to ASTM D 1037-93. In the physical properties of composites, water absorption decreased with the increase of target density and polypropylene fiber content. And the composites with fine wood particles appeared to have slightly lower water absorption than those with coarse wood particles. Thickness swelling did not vary significantly with the increase of target density but increased with the increase of wood particle content. And the composites with fine wood particles were significantly lower in thickness swelling than those with coarse wood particles. In the mechanical properties of composites, dry and wet MOR showed the increasing tendency with the increase of polypropylene fiber content and target density. Dry and wet MOE showed the increasing tendency with the increase of target density but only wet MOE exhibited the increasing tendency with the increase of polypropylene fiber content. Composites with fine wood particles appeared to be generally higher in wet MOR and MOE than those with coarse wood particles. In conclusion, composites with fine wood particles showed generally higher performance than those with coarse ones. Also, composites were significantly superior to control particleboards in the performance, especially in water absorption and thickness swelling.