• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.3B
• /
• pp.221-232
• /
• 2011

Applicability of three soil erosion models for burnt hillslopes was evaluated. The models were estimated with the data from plots established after tremendous wildfire occurred in the east coastal region. Soil erosion and surface runoff were simulated by the Water Erosion Prediction Project (WEPP) and the Revised Universal Soil Loss Equation (RUSLE) of application mode for disturbed forest areas and the Soil Erosion Model for Mountain Areas (SEMMA) developed for burnt hillslopes. Simulated sediment yield and surface runoff were compared with the measured those. In maximum value of sediment yield, three models was under-predicted and RUSLE and WEPP had difference of over two times. SEMMA showed the best model response coefficient, determination coefficient and the model efficiency. In application of models to the soil erosion according to the elapsed year after wildfire, all models were underestimated in initial stage disturbed by wildfire. Evaluation of models in this burnt hillslopes was shown the tends to under-predict soil erosion for larger measured values. Although a lot of sediment can be generated in small rainfall event as fine-grained soil of the high water repellency was exposed excessively right after wildfire, this under-prediction was shown that those models have a limit to estimate the weighted factors by wildfire.

• Journal of Korean Society of Forest Science
• /
• v.94 no.1 s.158
• /
• pp.16-20
• /
• 2005

Tricholoma matsutake ectomycorrhizas are unique in their morphology: not bifurcated broom shaped roots with not easily wettable brilliant and profuse white hyphae. To understand these characteristics the ectomycorrhizas were investigated with electron microscopy. T. matsutake ectomycorrhiza have thin mantle and typical Hartig net development in the epidermis and cortex, but no fungal mantle on the root apex. There were no penetrating hyphae inside of the cells of either epidermis, cortex or stele. Inside of the walls of epidermis and cortex cells are lined with ca. $2{\mu}m$ hemispherical amyloplasts. The brilliant hyphal surface was covered with various fine amorphous granules. The hyphal cell wall was thin membrane less than $0.3{\mu}m$ thick. There is no clamp connection on the hyphae. This thin membraneous cell wall with high elasticity can be related to survival strategy of the species without plasmolysis under frequent soil water stress environment. And the coarse hyphal surface with some water repellency can control sudden inrush of water of the hyphae with an extremely low osmotic potential. It is concluded that no mantle on the tip can induce mycorrhizas not bifurcated and that finely coarse surface of T. matsutake hyphae can make the hyphae brilliantly white but less wetted.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.3
• /
• pp.197-205
• /
• 2011

Cellulose nanofibrils (CNF) with 50~100 nm diameter were manufactured from micro-size cellulose by an application of a high-pressure homogenizer at 1,400 bar. High strength nanopapers were prepared over a filter paper by a vacuum filtration from CNF suspension. After reinforcing and dispersing CNF suspension, hydroxypropyl cellulose (HPC) and polyvinyl alcohol (PVA)-based composites were tailored by solvent- and film-casting methods, respectively. After 2, 4, 6 and 8 passes through high-pressure homogenizer, the tensile strength of the nanopapers were extremely high and increased linearly depending upon the pass number. Chemical modification of 1H, 1H, 2H, 2H-perfluorodecyl-triethoxysilane (PFDTES) on the nanopapers significantly increased the mechanical strength and water repellency. The reinforcement of 1, 3, and 5 wt% CNF to HPC and PVA resins also improved the mechanical properties of the both composites.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.345-356
• /
• 1994

Each of the three cationized compounds synthesized previously, poly(OMA-co-DAMA)[PODC], poly(DMA-co-DAMA)[PDDC] and poly(EMA-co-DAMA)[PEDC] was blended with waxes, emulsifiers and cationized fatty carbamide(ODTCC) synthesized in this study for the preparation of some durable softening water-repellenting agents, PODCW, PDDCW and PEDCW. The results of washability, tearing strength, crease recovery and contact angle of the cotton fabrics treated with PODCW, PDDCW and PEDCW with and without textile finishing resin, showed remarkable improvement of the physical properties. Rating of water repellency of cotton fabric treated with PODCW was 80, but those treated with PDDCW and PEDCW were not high enough to use in industry. Proper curing temperature of the synthesized water-repelleting agents was $140^{\circ}C$; proper using concentration was 3wt%; sodium acetate was the best catalyst for water-repellenting agents among the used, and proper concentration was 0.6wt%. From the results of reaction mechanism of cellulosic fiber with water-repellenting agent and washability of the fibers treated with water-repellenting agents the prepared water-repellenting agent proved to be durable. Surface structures of cotton fabrics treated with water-repellenting agent were investigated by SEM.

• The Korean Journal of Pesticide Science
• /
• v.15 no.4
• /
• pp.471-478
• /
• 2011

The ginseng stem fungus gnat, Phytosciara procera, overwintered in old stems and roots of ginseng as a larvae from late September to early May in next year. In the late Spring they become pupa then emerged. Therefore, the first control period has to be set between late May and early June. It is a same period of elimination of ginseng flower stalks. Two or three times pest control might be needed per month for controlling adult of P. procera. Otherwise, the overwintered form as larva in old stem by removal of old stems of ginseng, the population of first generation of P. procera adults could be reduced. However, it seemed that the removal of old stems was not necessarily correlated with the population of P. procera adults in the next generation. Three kinds of environmental-friendly control agents that were mainly contained sophora extract, showed the highly insecticidal activities against larva of P. procera. Among them, one agent containing sophora extract and paraffin oil showed an ovicidal action as well as oviposition repellency.

• Journal of Sericultural and Entomological Science
• /
• v.28 no.1
• /
• pp.72-78
• /
• 1986

The studies were performed to investigate the optimum conditions for tannic processing of silk by use Chinese Gallotannin and synthesized tannic acid, which are aimed at weighting, dyeing and physical properties of tannin treated silk. 1. It was reasonable that the concentration of tannin solution is 30 grams per liter of Chinese Gallotannin, 15 grams per liter of tannic acid for the efficient weighting of processed silk. The temperature and time for tannin treatment was optimum at 80$^{\circ}C$, 60 minutes and the acidity of tannin solution at pH 2 to 3. 2. In dyeing the tannintreated silk by Acid dye Orange II, the temperature and time was reasonable at 60$^{\circ}C$, 90 minutes to control the desorption of tannin components weighted onto silk. 3. The colour differences ($\Delta$E) of dyed silk fabric by soaping could be remarkably narrowed by tannin treatment, resulting in improving the washing fastness of tannin treated silk by two grades more than that of untreated one. 4. The light fastness of tannin treated silk could be drastically improved by reducing the dye-loss of dyed silk fabric which was coused from the Ultra-violet ray irrdiation. 5. The rubbing fastness and water repellency of tannin treated silk was at the same level with that of untreated one. However, the Drape coefficient of tannin treated silk was decreased more than that of untreated one, which is closely related with fabric softness and dressing appearence.

• Korean journal of applied entomology
• /
• v.60 no.3
• /
• pp.315-322
• /
• 2021

This study investigated the acaricidal and repellent activities of various plant extracts and Cnidium officinale-derived materials against Haemaphysalis longicornis. Among the 24 methanolic plant extracts, C. officinale showed the highest acaricidal activity (93.3%) against H. longicornis. Platycodon grandiflorus, Phytolacca americana, Magnolia denudata, Houttuynia cordata, C. officinale, and Pueraria montana showed significant differences in their repellent activity. Consequently, the activity of solvent-fractionated materials and the derived material of the C. officinale, was investigated and a 90% acaricidal effect was observed three days after hexane fraction treatment, indicating that the repellent response was statistically significant. Butylidenephthalide, which is a C. officinale-derived compound, showed 90% acaricidal activity seven days after treatment. Additionally, all H. longicornis moved to the untreated area in the t-tube olfactometer experiment, confirming the repellent activity of butylidenephthalide. Therefore, the results of this study suggest the use of C. officinale crude extract and butylidenephthalide as potent acaricidals and repellents against H. longicornis, respectively.

• The Journal of Engineering Geology
• /
• v.33 no.1
• /
• pp.69-83
• /
• 2023

Forest fires increase the risk of subsequent soil erosion and mass movement in burned areas, even under rainfall conditions below landslide alert thresholds, by destroying plants and vegetation and causing changes to soil properties. These effects of forest fires can alter runoff in burned areas by altering soil composition, component minerals, soil water repellency, soil mass stability, and soil fabric. Heat from forest fires not only burns shallow organic matter and plants but also spreads below the surface, affecting soil constituents including minerals. This study analyzed X-ray diffraction and physical properties of topsoil and subsoil obtained from both burned and non-burned areas to identify the composition and distribution of clay minerals in the soil. Small amounts of mullite, analcite, and hematite were identified in burned soils. Vermiculite and mixed-layer illite/vermiculite (I/V) were found in topsoil samples from burned areas but not in those from non-burned areas. These findings show changes in soil mineral composition caused by forest fires. Expansive clay minerals increase the volume of soil during rainfall, degrading the structural stability of slopes. Clay minerals generated in soil in burned areas are therefore likely to affect the long-term stability of slopes in mountainous areas.

• Korean Journal of Soil Science and Fertilizer
• /
• v.41 no.4
• /
• pp.260-266
• /
• 2008

Small lysimeter experiment under rain shelter plastic film house was conducted to investigate the effect of soil characteristics on the leaching and soil solution concentration of nitrate and phosphate. Three soils were obtained from different agricultural sites of Korea: Soil A (mesic family of Typic Dystrudepts), Soil B (mixed, mesic family of Typic Udifluvents), and Soil C (artificially disturbed soils under greenhouse). Organic-C contents were in the order of Soil C ($32.4g\;kg^{-1}$) > Soil B ($15.0g\;kg^{-1}$) > Soil A ($8.1g\;kg^{-1}$). Inorganic-N concentration also differed significantly among soils, decreasing in the order of Soil B > Soil C > Soil A. Degree of P saturation (DPS) of Soil C was 178%, about three and fifteen times of Soil B (38%) and Soil A (6%). Prior to treatment, soils in lysimeters (dia. 300 mm, soil length 450 mm) were tabilized by repeated drying and wetting procedures for two weeks. After urea at $150kg\;N\;ha^{-1}$ and $KH_2PO_4$ at $100kg\;P_2O_5\;ha^{-1}$ were applied on the surface of each soil, total volume of irrigation was 213 mm at seven occasions for 65 days. At 13, 25, 35, 37, and 65 days after treatment, soil solution was sampled using rhizosampler at 10, 20, and 30 cm depth and leachate was sampled by free drain out of lysimeter. The volume of leachate was the highest in Soil C, and followed by the order of Soils A and B, whereas the amount of leached nitrate had a reverse trend, i.e. Soil B > Soil A > Soil C. Soil A and B had a significant increase of the nitrate concentration of soil solution at depth of 10 cm after urea-N treatment, but Soil C did not. High nitrate mobility of Soil B, compared to other soils, is presumably due to relatively high clay content, which could induce high extraction of nitrate of soil matrix by anion exclusion effect and slow rate of water flow. Contrary to Soil B, high organic matter content of Soil C could be responsible for its low mobility of nitrate, inducing preferential flow by water-repellency and rapid immobilization of nitrate by a microbial community. Leached phosphate was detected in Soil C only, and continuously increased with increasing amount of leachate. The phosphate concentration of soil solution in Soil B was much lower than in Soil C, and Soil A was below detection limit ($0.01mg\;L^{-1}$), overall similar to the order of degree of P saturation of soils. Phosphate mobility, therefore, could be largely influenced by degree of P saturation of soils but connect with apparent leaching loss only more than any threshold of P accumulation.

• 보존과학연구
• /
• s.33
• /
• pp.45-55
• /
• 2012

A beeswax-treated paper has no air permeability but has the water repellency compared with a general Hanji. Because of these properties, the differences of the aging factors and mechanisms between the outer partition of beeswax-treated paper that is affected by the surrounding conservation environment and the inner partition of it that is not affected are bigger than general books. In this research, we analyzed and compared the aging characteristics through the accelerated aging of the beeswax-treated paper by some air and humidity conditions. The results of the physical and optical analysis after the artificial aging, it was shown that the oxygen accelerates the aging of the beeswax-treated paper and the condition with the humidity 50% RH is more stable than the condition with the humidity 0% RH. The results of the CG/MS analysis that was conducted to figure out the decomposition charateristics of the beeswax according to the air quality and the humidity, a low molecular weight compound that the number of carbon is C9-C20 including a fatty acid such as a palmitic acid was increased as the aging was progressed. However, under the same environment, a compound that the number of carbon is C21-C36 including a hydrocarbon and a aliphatic alcohol and a high molecular weight compound that the number of carbon is more than C34 including a wax ester were decreased. A rate of change according to the air quality and the humidity was similar to the beeswax-treated papers.