• Journal of Korean Society of Forest Science
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• v.99 no.2
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• pp.204-212
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• 2010

This study was performed in 22 unthinned Larix olgensis plantations in northeast China. Data were collected on 95 sample trees of different canopy positions and the diameter at breast height ($d_{1.3}$) ranged from 5.7 cm to 40.2 cm. The individual tree models for the prediction of vertical distribution of live crown, branch and needle biomass were built. Our study showed that the crown, branch and needle biomass distributions were most in the location of 60% crown length. These results were also parallel to previous crown studies. The cumulative relative biomass of live crown, branch and needle were fitted by the sigmoid shape curve and the fitting results were quite well. Meanwhile, we developed the crown ratio and width models. Tree height was the most important predictor for crown ratio model. A negative competition factor, ccf and bas which reflected the effect of suppression on a tree, reduced the crown ratio estimates. The height-diameter ratio was a significant predictor. The higher the height-diameter ratio, the higher crown ratio is. Diameter at breast height is the strongest predictor in crown width model. The models can be used for the planning of harvesting operations, for the selection of feasible harvesting methods, and for the estimation of nutrient removals of different harvesting practices.

• Journal of the Korean Society of Combustion
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• v.14 no.4
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• pp.17-24
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• 2009

Reburning is one of the most useful technologies for reducing nitric oxide in economically and technically. The reburning process was demonstrated as an effective NOx reduction method through injection of a secondary hydrocarbon fuel. An experimental study has been conducted to evaluate the effect of biomass reburning on NOx and CO formation in a light oil flamed combustion furnace. Reburning tests on NOx reduction of air-carried rice husk powder as the reburn fuel and light oil as the main fuel were performed in flames stabilized by a co-flow swirl and fuel staged burner, which was mounted at the front of the furnace. The results included flue gas emissions and temperature distribution in the furnace for several kinds of experimental conditions. It was observed clearly that NOx concentrations in the exhaust have considerably decreased due to effect of biomass reburning. The maximum NOx reduction rate was 42% when the reburn fuel fraction was 0.18. The CO emissions were kept under 42 ppmv in all experimental tests. And this paper makes clear that in order to decrease NOx concentration in the exhaust when the biomass reburning system is adapted, the control of some factors such as reburn fuel fraction and reburn zone fraction is very important.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.09a
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• pp.15-32
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• 2006

Biomass had been attracted public attention as eco-friendly resource which not increases the greenhouse gas like carbon dioxide. In this study, it had been collected pyrolytic products such as bio-oil, char and pyrolytic gas from various biomass in a fluidized bed reactor which is one of the fast pyrolysis processes. To understand the characteristics of biomass pyrolysis, the variation of products yield and chemical composition was determined with various operating parameters like temperature, gas velocity($U_{0}/U_{mf}$) and bed height(L/D). In the optimum operating conditions, gas yield and water content was the lowest and concentration of guaiacols and syringols were the highest. The maximum yields of bio-oil was from 55% to 58% at $400^{\circ}C$.

• New & Renewable Energy
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• v.20 no.1
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• pp.145-174
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• 2024

Addressing climate change necessitates evidence-based policies grounded in science. The use of forest biomass for energy production is based on a broad scientific consensus at the international level. However, some environmental groups in South Korea are opposing this system of energy production. Through this study, the authors aim to reduce unnecessary confusion and foster an atmosphere conducive to meaningful evidence-based policies. We have classified the issue into eight categories: biological carbon cycle, carbon debt, nature-based solutions, air emissions, cascading principles and sustainability certification, forest environmental impacts, climate change litigation, and the behavior of environmental groups and public perception. Consequently, the following key points were derived: (1) the actions of some environmental groups seem to follow a similar pattern to denialist behavior that denies climate change and climate science; (2) the quality of evidence for campaigns that oppose the use of forest biomass for energy production is low, with a tendency to overgeneralize information, high uncertainty, and difficulty in finding new claims.; (3) most of the public believes that forest biomass energy is necessary, and the governments of major countries are aware of its importance. Significantly, Forest biomass for energy is based on an overwhelming level of scientific consensus recognized internationally.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.281-285
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• 2007

We conducted research to determine the effects of forest tending works (FTW) on forest carbon (C) storage in Korean red pine forests by estimating changes in the quantity and distribution of stored organic C in an approximately 40-year-old red pine stand after FTW. We measured organic C storage (above- and belowground biomass C, forest floor C, and soil C at 50 cm depth) in the Hwangmaesan Soopkakkugi model forest in Sancheonggun, Gyeongsangnam-do before and after the forest was thinned from a density of 908 trees/ha to 367 trees/ha. The total C stored in tree biomass was 69.5 Mg C/ha before FTW and 38.6 Mg C/ha after FTW. The change in total C storage in tree biomass primarily resulted from the loss of 19.9 Mg C/ha stored in stem biomass after FTW. The total C pool in this red pine stand was 276 Mg C/ha before FTW and 245.1 Mg C/ha after FTW. Prior to FTW, 71.5% of the total C pool was stored in mineral soil, 25.2% in tree biomass, and 3.3% in the forest floor, where as after FTW 80.5% of the total C pool was stored in mineral soil, 15.7% in tree biomass and 3.7% in the forest floor. These results suggest that the development of site-specific tending techniques may be required to minimize the loss of tree biomass C storage capacity in red pine stands from FTW.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.384-395
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• 2012

This study was performed to develop the source profiles for fine particles ($PM_{2.5}$) emitted from the biomass burning. The multi-method research strategy included a usage of combustion devices such as field burning, fireplace, and residential wood burning to burn rice straw, fallen leaves, pine tree, and oak tree. The data were collected from multiple sources and measured water-soluble ions, elements, elemental carbon (EC), and organic carbon (OC). From this study, it turned out that OC (34~67%) and EC (1.2~39%) are the major components emitted from biomass burning. In the case of burning rice straw at field burning, OC (66.6%) was the most abundant species, followed by EC (4.3%), $Cl^-$ (3.6%), Cl (2.1%), and $SO^{2-}_4$(1.9%). Burning rice straw, fallen leaves, pine tree, and oak tree at fireplace, the amount of OC was 58.5%, 52.7%, 52.5%, and 61.2%, and that of EC was 1.2%, 18.4%, 36.5%, and 2.7%, respectively. The ratio of OC for the burning of pine tree and oak tree from the residential wood burning device was 56.9% and 34.3%, and that of EC was 25% and 38.6%, respectively. Applying the measured data with respect to the proportion of components emitted from biomass burning to reference model, it turned out that self-diagnosed result was appropriate level, and the result based on the model is in highly corresponding to actual timing of biomass burning.

• KSBB Journal
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• v.27 no.2
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• pp.97-102
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• 2012

In the present study, the biomass productivity of two green microalgae (Chlorella sp. and Dunaliella salina DCCBC2) were assessed in a 12 L tubular photobioreactor under optimum culture conditions. In the batch culture optimization process, the Chlorella sp. biomass was obtained as 1.2 g/L under atmospheric air as a sole $CO_2$ source and other culture conditions as follows: light intensity, temperature, pH, $NH_4Cl$ and $K_2HPO_4$ were 100 ${\mu}E/m^2/s$, $27^{\circ}C$, 7.0, 20.0 mM and 2.0 mM, respectively. On the other hand, 2.9 g/L of D. salina DCCBC2 biomass production was observed under the following conditions: light intensity, temperature, pH, $KNO_3$ and $K_2HPO_4$were 80 ${\mu}E/m^2/s$, $27^{\circ}C$, 8.0, 3.0 mM and 0.025 mM, respectively. At 1% $CO_2$ supply to the reactor, the Chlorella sp. production was reached 1.53 g/L with 25% increment under the same operating conditions. In addition, the maximum D. salina DCCBC2 biomass was observed as 3.40 g/L at 3% $CO_2$ concentration. Based on the aforementioned optimized conditions, the dilution rate and maximal biomass productivity of Chlorella sp. and D. salina DCCBC2 in the continuous cultivation were 0.4/d and 0.6 g/L/d and 0.6/d and 1.5 g/L/d, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.969-976
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• 2015

Macroalgal community structure was seasonally examined at Hakampo (Taean) in western coast of Korea from February 2007 to October 2010. Also, the effects of "Hebei Spirit" oil spill on the seaweed community structure were evaluated. A total of 101 macroalgal species were identified, comprising 12 green, 18 brown and 71 red algae. Species richness ranged 58-65 species with maximal in 2008 and minimal in 2009. Seaweed biomass ranged $75.81-102.06g\;dry\;wt./m^2$ (mean, $88.78g/m^2$) with maximal in 2008 and minimal in 2010. Vertical distribution from the high to low intertidal zone was Neorhodomela aculeata and Polyopes affinis; Corallina pilulifera and Chondrus ocellatus; Sargassum thunbergii and Ulva australis. Coarsely-branched seaweeds comprised the highest proportion of biomass ($37.17g/m^2$, or 41.86% of the total biomass) and ecological state group I (ESG I) seaweed biomass was between 81.67-85.44%. Also, ephemeral macroalgae including Ulva species sharply increased in species number and biomass within 1-2 year from the "Hebei Sprit" oil spill in the mid and low intertidal zone. Hakampo rocky shore is still good condition as evaluated based on macroalgal species number, biomass, and composition in functional form and ESG I seaweeds.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.61-64
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• 2013

Biomass is well known for organic resources photosynthesized by carbon dioxide water in the air and thus it can be widely used in the form of energy and production for various kinds of materials. Through pyrolysis, biomass can be transformed into solid(biochar), liquid(bio-oil), and combustible gas on the different condition of temperature and heating rate. That's why biomass can be practically used to preprocess and produce a variety of elements. This work is to analyze the characteristics of slow pyrolysis of three different kinds of biomass extracted from Indonesia. They showed similar moisture content and combinations of combustible matters and had quite a large discrepancy in the ash among them like 2.1 & of Bagasse, 91% of PKS, and 20.9% of Paddy Straw, respectively. yield of biochar, solid form of the biomass, steadily decreased when the temperature went up and that of bio-oil the highest at the temperature of 500 degrees Celsius. At the same temperature range, PKS bio-oil showed 51.4 % of yield and Bagasse had 55.1% while it turned out that Paddy straw showed the lowest yield of 37.2%. The apparent density was also measured to figure out the density of each product from the pyrolysis experiments at the temperature of 500 degrees Celsius. The result was like these; the density of biochar was 0.17, the lowest, and that of Tree stem was 1.3 when mixed by an equal amount of biochar and bio-oil.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.453-465
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• 2014

The paper provides a review on bio-oil production technology from biomass by using fast pyrolysis to use heating fuel, power fuel and transport fuel. One of the most promising methods for a small scale conversion of biomass into liquid fuels is fast pyrolysis. In fast pyrolysis, bio-oil is produced by rapidly heating biomass to intermediate temperature ($450{\sim}600^{\circ}C$) in the absence of any external oxygen followed by rapid quenching of the resulting vapor. Bio-oil can be produced in weight yield maximum 75 wt% of the original dry biomass and bio-oils typically contain 60-75% of the initial energy of the biomass. In this study, it is described focusing on the characterization of feedstock, production principle of bio-oil, bio-oil's property and it's application sector.