• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.116-125
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• 2014

Pyrolysis oil (PO), derived from biomass through fast pyrolysis process have the potential to displace significant amounts of petroleum fuels. The PO derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, the use of PO in a diesel engine is very limited due to its poor properties like low energy density, low cetane number, high acidity and high viscosity of PO. Therefore, one of the easiest way to adopt PO to diesel engine without modifications is blended with other fuels that have high centane number. However, PO that has high amount of polar chemicals is immiscible with non polar hydrocarbons of diesel or biodiesel. Thus, to stabilize a homogeneous phase of diesel/biodiesel-PO blends, a proper surfactant should be used. Nevertheless, PO which was produced from different biomass type have varied characteristics and this complicates the selection of a suitable additive for a specific PO-diesel emulsion. In this regard, a more simple approach such as the use of a co-solvent like ethanol or butanol to induce a more stable phase of the PO-diesel mixture could be a promising alternative. In this study, a diesel engine operated with diesel/biodiesel-PO-butanol blends was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine were examined under the engine loads of IMEP 0.2 ~ 0.8MPa.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.31-38
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• 2013

Annual ring formation is considered a source of information to investigate the effects of environmental changes caused by temperature, air pollution, and acid rain on tree growth. A comparative investigation of annual ring growth of Cryptomeria japonica in relation to environmental changes was conducted at two sites in southern Korea (Haenam and Jangseong). Three wood disks from each site were collected from stems at breast height and annual ring growth was analyzed. Annual ring area at two sites increased over time (p > 0.05). Tree ring growth rate in Jangseong was higher than that in Haenam. Annual ring area increment in Jangseong was more strongly correlated with environmental variables than that in Haenam; annual ring growth increased with increasing temperature (p < 0.01) and a positive effect of $NO_2$ concentration on annual ring area (p < 0.05) could be attributed to nitrogen deposition in Jangseong. The correlation of annual ring growth increased with decreasing $SO_2$ and $CO_2$ concentrations (p < 0.01) in Jangseong. Variation in annual growth rings in Jangseong could be associated with temperature changes and N deposition. In Haenam, annual ring growth was correlated with $SO_2$ concentration (p < 0.01), and there was a negative relationship between precipitation pH and annual ring area (p < 0.01) which may reflect changes in nutrient cycles due to the acid rain. Therefore, the combined effects of increased $CO_2$, N deposition, and temperature on tree ring growth in Jangseong may be linked to soil acidification in this forest ecosystem. The interactions between air pollution ($SO_2$) and precipitation pH in Haenam may affect tree growth and may change nutrient cycles in this site. These results suggested that annual tree ring growth in Jangseong was more correlated with environmental variables than that in Haenam. However, the further growth of C. japonica forest at two sites is at risk from the long-term effects of acid deposition from fossil fuel combustion.

• Korean Journal of Human Ecology
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• v.12 no.1
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• pp.85-94
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• 2003

With 106 detached houses where the elderly people lives, this study was conducted to perform a survey of their residential environment. The results of this study were summarized as follows: While the surveyed houses' safety, sanitation and convenience appeared to be positive, with respect to the conditions of location, 73.6% of the surveyed houses did not meet the requirements for comfort. The average area of each space indicated that the bed room was $12.09m^2$, the living room $14.38m^2$, the kitchen $8.96m^2$, the bath room $3.93m^2$, and the rest room $259m^2$. Then, 93.3% of the bed room had the doorsill. Also, 97.2% of the surveyed houses had retrievable space. The forms of the living room door were a hinged door(55.7%) and a sliding door(44.3%). The 43.4% of the finished material of the living room was wood which was highest. The cooking table forms of kitchen were mainly "ㄱ"-shaped(50.0%) and "ㅡ"-shaped(48.0%), and their average height was 815mm. The fuel used for kitchen was mainly the gas which accounted for 93.4%, but 95.3% of houses had no gas-warning devices. Most houses(77.4%) had an integrated type of bathroom and toilet. In addition, 63.2% houses had the stepped difference between the bathroom and other spaces. But they had no a sliding-prevention devices(not for 92.5%) or heating systems(not for 93.4%) in the bathroom.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.79-88
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• 2008

The production of bioethanol, which is one of the alternative fuel, cause the various problem such as agflation in human society. As a substitute for the feedstock, lignocellulosic biomass have a big potential. However, bioethanol production with cellulosic material is not commercialized due to high cost. Thermochemical pretreatment to improve the rate of enzyme hydrolysis and increase the recovery of fermentable sugar, is required in order to achieve the cost down in bioethanol production. In this study, various problems and technologies for pretreatment is introduced. Acid hydrolysis, alkali hydrolysis, steam explosion, organosolv process, ammonia explosion, and wet oxidation pretreatment remove lignin and hemicellulose, and reduce cellulose crystallinity. Optimization of pretreatment process on various sources of lignocellulosic biomass such as softwood, hardwood, and straw should be performed.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.214-225
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• 2016

Gasification is one of the important contribution to resource recycling by conversion of biomass to a variety of energy sources such as alcohol, SNG etc., and to global warming prevention by reduction of green house gases such as $CO_2$. The aim of this study is to draw the optimal operation condition of dual fluidized-bed gasifier with biomass fuel, to verify SNG production efficiency and to establish the basis for the domestic commercialization of dual fluidized bed gasification. As a result, dual fluidized-bed gasifier has the optimal conditions at $826^{\circ}C$ with steam input 1,334 g/hr, air input 5.56 L/min. The carbon conversion is 81% and SNG production efficiency was $CH_4$ 92%.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.241-254
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• 2015

This study attempts to examine farmers' preference and perception towards cropland agroforestry (CAF) and its economic benefits in Bangladesh. It surveys 84 farmers of two sub-districts named Manirampur and Bagherpara under Jessore district of Bangladesh to address the study objectives with the help of a questionnaire during the period of June to July 2013. We follow a multistage random sampling procedure for selecting respondents of the survey. A total of 27 plant species under 19 families are identified in the surveyed crop fields, among which 11 are tree species and 1 is shrub from 8 families and 15 species are agricultural crops from 11 families. According to the survey findings, most of the farmers prefer multipurpose tree species like Swietenia macrophylla (67 percent), Phoenix sylvestris (48 percent), Mangifera indica (48 percent) and Cocos nucifera (43 percent). We also find that Curcuma longa (92 percent), Oryza spp. (56 percent), Solanum melongena (43 percent) and Amorphophallus campanulatus (33 percent) are the available agriculture crops which are grown in association with trees in the study area. The surveyed farmers report that they practice CAF to get fuel wood, fodder, juice, fruit and food for family consumption and revenue earnings. About 76 percent of the surveyed farmers endorse the existence of a positive interaction between trees and agriculture crops, while the rest 24 percent endorse the existence of a negative interaction between trees and agriculture crops. This study finds that CAF farmers on an average earn US$ 1,410 per farm per year and the yearly average revenue difference between CAF and non-cropland agroforestry (NCAF) farmers is US$ 214. Overall, CAF needs to develop through scientific intervention in the study area to conserve the biodiversity and to enhance farmers' sustainable livelihood.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.683-690
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• 2017

Wood pellet (WP), empty fruit bunch (EFB) and palm kernel shell (PKS) which are biomass fuels for power generation are selected to study the characteristics of torrefaction process. These biomass fuels are torrefied at $220^{\circ}C$, $250^{\circ}C$, and $280^{\circ}C$. The heating value of biomass fuels is increased depending on the torrefaction temperature. However, due to energy yield decline, it is not always desirable to torrefy biomass at higher temperature. Considering the mass yield and energy yield after torrefaction, the most proper temperature conditions for torrefaction of WP is $250-280^{\circ}C$ and for EFB, PKS are $220-250^{\circ}C$. Additionally, to investigate the phenomenons of chlorine release during torrefaction process, Ion Chromatography (IC) method was used. In the case of EFB and PKS torrefied at $300^{\circ}C$, the chlorine component has been reduced by 97.5% and 95.3% compared to the raw biomass, respectively. In conclusion, torrefied biomass can be used as alternative fuels in replacement of coals for both aspects of heating value and chlorine corrosion problems.

• 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.10 no.4
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• pp.34-41
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• 2001

A research was performed to evaluate a use of shredder residue to currently dispose of at landfills. Laboratory analyses were conducted to determine especially the fuel characteristics of shredder residue. For this aim, shredder residue was classified by the particle size as well as by the type of material and the content of Cl, S, ash, and calorific value were determined. Due to the chlorinated plastic content of shredder residue, mean concentration of Cl was found to exceed 4wt% except one sample while that of S was ranged from 0.25 to 0.39 wt%. As far as calorific value was concemed, plastic was observed to be more than 10,000 kcal/kg while wood/paper and fiber accounted for approximately 4,000 kcal/kg. Shredder residue was found to contain varying trace amounts of metal elements, including Fe of 6∼8.5 wt%. Hg and Cr(VI) were not detected, however, while Cd was contained as small as 0.0004-0.0009 wt%.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_1
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• pp.149-159
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• 2022

Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.