• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.315-321
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• 2012

Fate of acetamiprid and imidacloprid aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) were studied in a forest of Haman area. Acetamiprid 20% SL or imidacloprid 20% DC were diluted 100 times and applied two times as rate of 50 L/ha using an aircraft of Bell 206 L helicopter. Average acetamiprid deposits on forest floor ranged from 2 to 4% of standard aerial application rate. Following to the second application, acetamiprid deposits in the pine needle ranged 1.8~8.5 mg/kg and then gradually decreased to 1.2~2.1 mg/kg after 48 days. Deposits on the plant washed off by rainfall and reached to soil surface was ca. 17% of the application rate. All of acetamiprid on the ground resided in the forest floor covering the soil surface, where acetamiprid residues were decreased to a quarter at 48 days after the second application, but they were not detected in soil beneath it. And the only low level of acetamiprid residues, 0.0003 mg/L, was detected in the reservoir nearby the experimental forest on the day of aerial application. The acetamiprid detection was presumably due to spray drift. And average imidacloprid deposits on forest floor ranged from 1 to 3% of standard aerial application rate. Following to the second application, imidacloprid deposits in the pine needle analysed very low concentration of 0.1 mg/kg, but the amount of imidacloprid in wash-off in standard and two-fold treatment were ca. 8% and 4% of the application rate, respectively. Most of imidacloprid on the ground also resided in the forest floor, where imidacloprid residues were decreased to a twentieth at 111 days after the second application, and they were detected below 0.5% of the application rate in sol beneath it. And the low level of imidacloprid, 0.0003~0.0017 mg/L, were detected in the streams in the experimental forest. It was not to the level of contamination concerns.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.54-59
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• 2012

This study investigates the effect of ${\beta}$-glucans on the growth of Caenorhabditis elegans. Comparison was made among lipopolysaccharide (LPS) and ${\beta}$-glucans extracted from Phellinus baumii, in the presence of peptidoglycans which is available as the major carbon source from OP50, a non-pathogenic strain of Escherichia coli. When the three sources of carbohydrate were added singularly or in mixture to the culture media, a significant level of variation was observed with respect to fecundity. Addition of ${\beta}$-glucans appeared to increase the fecundity. When ${\beta}$-glucans was reinforced in the culture media, the fecundity increased at least 20 percent compared to the OP50-only media which exclusively contains peptidoglycans. In terms of life span, C. elegans showed a modest reduction when treated especially with ${\beta}$-glucans. C. elegans accumulated less fat in the ${\beta}$-glucans containing media different from the OP50 media. Based on the Sudan black staining, fat deposition significantly decreased corresponding to the ${\beta}$-glucans content in the media. On LPS-supplemented media, no difference was observed in fat deposition compared to the normal OP50 media. At the level of motility, ${\beta}$-glucans-treated worms moved more distance as well as LPS-treated worm. They also showed a comparable degree of motility under similar treatment with each source of carbohydrate. In conclusion, LPS and ${\beta}$-glucans, extracted from P. baumii, may not entirely replace the food required for C. elegans; however, it might be utilized as valuable alternative food source which C. elegans use as forms of carbohydrates in stead of peptidoglycan of OP50.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.94-104
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• 2009

It is urgently required to develop the production of fermentation-heat energy from the waste agricultural and forest biomass and its effective heat exchanging system for the supply of warm water to rural households and greenhouses. In this study 3 helical-type and 1 plate-type heat exchangers using 3 different waste biomasses [e.g. hardwood (HW) sawdust (100%), softwood (SW) sawdust : HW sawdust (50 : 50) and HW sawdust : grass (90 : 10)] were applied in order to find out the best heat recovery system. The heat exchanger was basically considered to improve the overall heat recovery efficiency, to minimize heat loss and to simplify manufacturing, assembling and breaking up the fermenting beds. The helical-type heat exchanger (HX-H3) installed in fermenting bed of HW sawdust : grass (90 : 10) showed relatively higher temperature profiles, in particular mid- and upper-parts than lower and surface parts during 45-day fermentation process. The maximum temperature was ranged from $40^{\circ}C$ to $65^{\circ}C$ with average $60^{\circ}C$. The water temperature of tank outlet was ranged to $33{\sim}48^{\circ}C$ during whole measuring periods. By the way plate-type one (HX-P) installed in same biomass compositional fermenting bed showed $64.5{\sim}76.5^{\circ}C$ at center part, and $43{\sim}56^{\circ}C$ and $42{\sim}58^{\circ}C$, water tank and tank outlet temperatures, respectively, during 100 day measurement. It could be concluded that the plate-type heat exchanger (HX-P) provides not only the effective heating for the rural households and greenhouses, but also having the best heat recovery performance, easy manufacturing, assembling and breaking up the systems.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.200-210
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• 2015

The modeling for fast pyrolysis of biomass in fluidized bed reactor has been developed for accurate prediction of bio-oil and gas products and for yield improvement. The purpose of this study is to analyze and to compare the CFD(Computational Fluid Dynamics) simulation results with the experimental data from the CFD simulation results with the experimental data from the reference(Mellin et al., 2014) for gas products generated during fast pyrolysis of biomass in fluidized bed reactor. CFD(ANSYS FLUENT v.15.0) was used for the simulation. Complex pyrolysis reaction scheme of biomass subcomponents was applied for the simulation of pyrolysis reaction. This pyrolysis reaction scheme was included reaction of cellulose, hemicellulose, lignin in detail, gas products obtained from pyrolysis were mainly $CO_2$, CO, $CH_4$, $H_2$, $C_2H_4$. The deviation between the simulation results from this study and experimental data from the reference was calculated about 3.7%p, 4.6%p, 3.9%p for $CH_4$, $H_2$, $C_2H_4$ respectively, whereas 9.6%p and 6.7%p for $CO_2$ and CO which are relatively high. Through this study, it is possible to predict gas products accurately by using CFD simulation approach. Moreover, this modeling approach should be developed to predict fluidized bed reactor performance and other gas product yields.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.107-121
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• 2010

We conducted a sensitivity test of Joint UK Land Environment Simulator (JULES), in which the influence of biophysical parameters on the simulation of gross primary productivity (GPP) and ecosystem respiration (RE) was investigated for two typical ecosystems in Korea. For this test, we employed the whole-year observation of eddy-covariance fluxes measured in 2006 at two KoFlux sites: (1) a deciduous forest in complex terrain in Gwangneung and (2) a farmland with heterogeneous mosaic patches in Haenam. Our analysis showed that the simulated GPP was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration for both ecosystems. RE was sensitive to wood biomass parameter for the deciduous forest in Gwangneung. For the mixed farmland in Haenam, however, RE was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration like the simulated GPP. For both sites, the JULES model overestimated both GPP and RE when the default values of input parameters were adopted. Considering the fact that the leaf nitrogen concentration observed at the deciduous forest site was only about 60% of its default value, the significant portion of the model's overestimation can be attributed to such a discrepancy in the input parameters. Our finding demonstrates that the abovementioned key biophysical parameters of the two ecosystems should be evaluated carefully prior to any simulation and interpretation of ecosystem carbon exchange in Korea.

• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.195-201
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• 1986

This study was conducted to investigate the life history of Compsidia populnea which is major species of the stem-borers on Populus alba{\times}glandulosa$. Peak emergence of the adult of Compsidia populnea L. was around 10th${\sim}$l2nd of May in Chuncheon vicinities, having one generation a year in Korea. There was a preovipositional period of 10.7 days and a ovipositional period of 14.3.days. Mean adult longevity was 11 days for male and 13.8 days for female. Individual eggs were long oval with somewhat narrowed tip at one side and soft, 2.6mm in length, 0.8mm in diameter, and were laid singly under the U-shaped scars which were made by female before oviposition. Total number of scars per female averaged 56.6 ($8{\sim}135$) and eggs were found in 67.9 percent of the total scars. Egg period was $8{\sim}11$ days at $25^{\circ}C$ constant temperature and $7{\sim}14$ days in the field condition. Early young larvae stayed for $2{\sim}3$ weeks under the scars and then boring into the xylem, forming galls at this time. Size of the gall was 1.8cm($1.3{\sim}2.5$) in length, 1.6cm($1.0{\sim}2.2$) in diameter and the length of mine was everage 3.1cm. Fully grown larvae were developed around the early October and overwintered in the mines of galls. Pupation was done around the early of April. Pupal developmental period averaged 11 days($9{\sim}13$ days) at $25^{\circ}C$ constant temperature condition.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.53-57
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• 2013

A severe defoliation by typhoon in early autumn reduces fruit quality for the current season and reserve accumulations for the next season. This study was conducted to determine the effects of foliar applications during the autumn on alleviating the damages after defoliation. Leaves of 2-year-old 'Fuyu' trees, grown in 50-L pots under a rain-shelter, were 75%-defoliated on September 9. In mid-September and early October, trees were treated either with eight foliar applications of urea or with four alternating applications of urea and $KH_2PO_4$ (urea + KP application), all at 0.5% (w/v). Trees untreated after the defoliation served as the control. The urea applications slightly increased N and P concentrations of the leaves collected on November 6, while urea + KP applications significantly increased P and K concentrations. Foliar applications did not affect fruit growth, but tended to decrease skin coloration. Fruit soluble solids increased by 1.5 and $1.0^{\circ}Brix$ for urea and urea + KP applications, respectively. There was a significant increase in dry weight of fine root for the foliar application treatments but not in those of aerial woods and larger roots. With the foliar applications, N concentration tended to increase in the permanent organs but not P and K, whereas soluble sugars and starch notably increased in shoot, trunk, or fine root regardless of the different applications. Results indicated that the foliar applications could partially help to restore fruit quality and carbohydrate accumulations in the defoliated trees.

• Journal of Life Science
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• v.28 no.11
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• pp.1339-1346
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• 2018

In Korea, edible mushrooms are produced largely on commercial artificial media, so the annual production of spent mushroom substrate (SMS), as a by-product of the mushroom industry, is estimated at over 200 million tons. This SMS is assumed to contain abundant fungal mycelia and pre-fruiting bodies, as well as various nutritive and bioactive compounds that are presently discarded. This study examined the physico-chemical, nutritional, and enzymatic characteristics of uninoculated sterilized medium (USM) and SMS of shiitake mushrooms with the aim of developing a high-value added product from SMS. The contents of crude protein, crude lipid, and ash were higher after the third SMS harvest ($SMS-A-3^{rd}$) than in USM or $SMS-A-1^{st}$. The contents of Ca, Mg, and P in $SMS-A-3^{rd}$ were 2.95, 2.35, and 2.1-fold higher compared than in USM. No As or Cd was detected in USM or SMS. The pH, Brix, and acidity were 4.6, 20.0, and 1.4, respectively in $SMS-A-3^{rd}$, but 5.6, 6.0, and 0.0, respectively, in USM. These results suggest a highly active production of soluble components and organic acids in $SMS-A-3^{rd}$. The distinct color differences noted for USM, $SMS-A-1^{st}$, and $SMS-A-3^{rd}$ could be used as a mycelial growth indicator. Enzyme activity assays using the APIZYM system showed that SMS is a potent source of hydrolysis-related enzymes, especially esterase (C4) and ${\beta}$-glucuronidase. Our results suggested that the SMS of shiitake has a high potential for use in environmental, agricultural, and stock-breeding industries, for example, as active ingredients for sewage treatment, waste-polymer degradation, and feed additives.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.622-629
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• 2022

The study aim was to derive a stem taper equation for Phyllostachys pubescens, a type of bamboo in South Korea, and to develop a stem volume table. To derive the stem taper equation, three stem taper models (Max & Burkhart, Kozak, and Lee) were used. Since bamboo stalks are hollow because of its woody characteristics, the outer and inner diameters of the tree were calculated, and connecting them enabled estimating the tree curves. The results of the three equations for estimating the outer and inner diameters led to selection of the Kozak model for determining the optimal stem taper because it had the highest fitness index and lowest error and bias. We used the Kozak model to estimate the diameter of Phyllostachys pubescens by stem height, which proved optimal, and drew the stem curve. After checking the residual degree in the stem taper equation, all residuals were distributed around "0", which proved the suitability of the equation. To calculate the stem volume of Phyllostachys pubescens, a rotating cube was created by rotating the stem curve with the outer diameter at 360°, and the volume was calculated by applying Smalian's method. The volume of Phyllostachys pubescens was calculated by deducting the inner diameter calculated volume from the outer diameter calculated volume. The volume of Phyllostachys pubescens was only 20~30% of the volume of Larix kaempferi, which is a general species. However, considering the current trees/ha of Phyllostachys pubescens and the amount of bamboo shoots generated every year, the individual tree volume was predicted to be small, but the volume/ha was not very different or perhaps more. The significance of this study is the stem taper equation and stem volume table for Phyllostachys pubescens developed for the first time in South Korea. The results are expected to be used as basic data for bamboo trading that is in increasing public and industrial demand and carbon absorption estimation.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.1-41
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• 1988

For the purpose of utilizing the sawdust having poor combining properties as board raw material and resulting in dimensional instability of board, polypropylene chip (abbreviated below as PP chip) or oriented PP thread was combined with sawdust particle from white meranti(Shorea sp.). The PP chip was prepared from PP thread in length of 0.25, 0.5, 1.0 and 1.5 cm for conventional blending application. Thereafter, the PP chip cut as above was combined with the sawdust particle by 3, 6, 9, 12 and 15% on the weight basis of board. Oriented PP threads were aligned with spacing of 0.5, 1.0 and 1.5cm along transverse direction of board. The physical and mechanical properties on one, two and three layer boards manufactured with the above combining conditions were investigated. The conclusions obtained at this study were summarized as follows: 1. In thickness swelling, all one layer boards combined with PP chips showed lower values than control sawdustboard, and gradually clear decreasing tendendy with the increase of PP chip composition. Two layer board showed higher swelling value than one layer board, but the majority of boards lower values than control sawdustboard. All three layer boards showed lower swelling values than control sawdustboard. 2. In the PP chip and oriented thread combining board, the swelling values of boards combining 0.5cm spacing oriented thread with 1.0 or 1.5cm long PP chip in 12 and 15% by board weight were much lower than the lowest of one or three layer. 3. In specific gravity of 0.51, modulus of rupture of one layer board combined with 3% PP chip showed higher value than control sawdustboard. However, moduli of rupture of the boards with every PP chip composition did not exceed 80kgf/cm2, the low limit value of type 100 board, Korean Industrial Standard KS F 3104 Particleboards. Moduli of rupture of 6%, 1.5cm-long and 3% PP chip combined boards in specific gravity of 0.63 as well as PP chip combined board in specific gravity of 0.72 exceeded 80kgf/$cm^2$ on KS F 3104. Two layer boards combined with every PI' chip composition showed lower values than control sawdustboard and one layer board. Three layer boards combined with.1.5cm long PP chip in 3, 6 and 9% combination level showed higher values than control sawdustboard, and exceeded 80kgf/$cm^2$ on KS F 3104. 4. In modulus of rupture of PP thread oriented sawdustboard, 0.5cm spacing oriented board showed the highest value, and 1.0 and 1.5cm spacing oriented boards lower values than the 0.5cm. However, all PP thread oriented sawdustboards showed higher values than control saw-dustboard. 5. Moduli of rupture in the majority of PP chip and oriented thread combining boards were higher than 80kgf/$cm^2$ on KS F 3104. Moduli of rupture in the boards combining longer PP chip with narrower 0.5cm spacing oriented thread showed high values. In accordance with the spacing increase of oriented thread, moduli of rupture in the PP chip and oriented thread combining boards showed increasing tendency compared with oriented sawdustboard. 6. Moduli of elasticity in one, two and three layer boards were lower than those of control sawdustboard, however, moduli of elasticity of oriented sawdustboards with 0.5, 1.0 and 1.5cm spacing increased 20, 18 and 10% compared with control sawdustboard, respectively. 7. Moduli of elasticity in the majority of PP chip and oriented thread combining boards in 0.5, 1.0 and 1.5cm oriented spacing showed much higher values than control sawdustboard. On the whole, moduli of elasticity in the oriented boards combined with 9% or less combination level and 0.5cm or more length of PP chip showed higher values than oriented sawdustboard. The increasing effect on modulus of elasticity was shown by the PP chip composition in oriented board with narrow spacing. 8. Internal bond strengths of all one layer PP chip combined boards showed lower values than control sawdust board, however, the PP chip combined boards in specific gravity of 0.63 and 0.72 exceeded 1.5kgf/$cm^2$, the low limit value of type 100 board and 3kgf/$cm^2$, type 200 board on KS F 3104, respectively. And also most of all two, three layer-and oriented boards exceeded 3kgf/$cm^2$ on KS F. 9. In general, screw holding strength of one layer board combined with PP chip showed lower value than control sawdustboard, however, that of two or three layer board combined with PP chip did no decreased tendency, and even screw holding strength with the increase of PP chip composition. In the PP chip and oriented PP thread combining boards, most of the boards showed higher values than control sawdustboard in 9% or less PP chip composition.