• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.56-68
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• 1997

This study was carried out to evaluate the capacity of environment purification of forest and to reveal formation processes of stream water quality by evaluating water quality variations in forest hydrological processes. Water quantity, pH, electric conductivity(EC), dissolved oxygen(DO), and dissolved matter concentrations were monitored in open rainfall, throughfall, stemflow, litter flow and short-term stream flow for one unit storm, and also for those were monitored in long-term stream flow in Palgong, Yongsung, and Daedong catchments. The results were summarized as follows; 1. pH and DO values of stream flow were increased as the flux increased but EC values were decreased. 2. pH values of stemflow and throughfall were decreased with the lapse of rainfall time with lower values than open rainfall. Arid EC values were higher in initial rainfall period but lower gradually with the lapse of time than open rainfall. In litter flow, pH values were lower than open rainfall but EC values were higher. In stream flow, pH values of stream flow showed a high level in initial rainfall period and decreased remarkably with the lapse of time, but it recovered after the rainfall stopped. And however, the values of EC showed almost reverse tendency. DO values of litter flow and stream flow were decreased gradually with the lapse of time in litter flow and stream flow but there were no any tendency in open rainfall, stemflow and throughfall. 3. pH values of stemflow and throughfall in Quercus acutissima were higher than in Pinus densiflora, but EC values were lower. Total amount of canons in stemflow was higher in Pinus densiflora than in Quercus acutissima. 4. pH, DO, EC and total amount of cation values in hydrological processes were in the order of; litter flow

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.415-421
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• 2004

Litter wastes on highway runoff are gradually being considered one of the major pollutants of concern in protecting the integrity of receiving waters for beneficial use. The California State Water Resources Control Board has identified in their 303(d) list at least 36 water bodies where trash or litter is considered a pollutant of concern. The first TMDL adopted by the Region 4 (Los Angeles area) of the California State Water Quality Control Board was for trash in the Los Angeles River. The first flush characteristic study was developed to obtain first flush water quality and litter data from representative stormwater runoff from standard highway drainage outfalls in the Los Angeles area. Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over two years. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. The event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. Event mean concentrations were ranged 0.0021 to 0.259g/L for wet gross pollutants and 0.0001 to 0.027g/L for wet litters. The first flush phenomenon was evaluated and the impacts of various parameters such as rainfall intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Litter volume and loading rates appear to be directly related to peak storm intensity, antecedent dry days and total flow volume.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.1
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• pp.111-122
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• 2009

Abatements of TN and ${NO_3}^-$-N in a horizontal subsurface-flow wetland with litter layer on its surface were compared with those without one. The wetland was constructed in 2001 on floodplain of the Gwangju Stream which flows through Gwangju City in Korea. Its dimensions were 29m in length, 9m in width and 0.65m in depth. A bottom layer of 45cm was filled with crushed granites (15~40mm in diameter) and a middle layer of 10cm had pea pebbles. An upper layer of 5cm contained coarse sands. Reeds (Phragmites australis) growing in natural wetlands were transplanted on its surface. Water of the stream was channelled into the wetland by gravity flow and its effluent was discharged back into the stream. Average Litter layer of 12.2cm was formed on its surface in 2007. The layer and above-ground parts of reeds were eliminated in April 2008. Volumes and water quality of influent and effluent of the wetland were analyzed from May to November in 2007 and 2008, respectively. Inflow into the wetland both in 2007 and 2008 averaged approximately 40$m^3$/day and hydraulic residence time both in 2007 and 2008 was about 1.5days. Influent TN concentration in 2007 and 2008 averaged 3.96 and 3.89mg/L, respectively and average influent ${NO_3}^-$-N concentration in 2007 and 2008 was 2.11 and 2.05mg/L, respectively. With a 0.05 significance level, influent concentrations of TN and ${NO_3}^-$-N, temperatures and pH of effluent, and heights and stem numbers of reeds showed no difference between the wetland with litter layer and without one. TN retention in the wetland with litter layer and without one averaged 64,76 and 54.69%, respectively and ${NO_3}^-$-N removal averaged 60.83 and 50.61%, respectively. Both TN and ${NO_3}^-$-N abatement rates in the wetland with litter layer were significantly high (TN abatement: p<0,001, ${NO_3}^-$-N abatement: p=0.001) when compared with those without one. The subsurface-flow wetland having litter layer on its surface was more efficient for TN and ${NO_3}^-$-N removal.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1634-1641
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• 2003

In vivo digestion and metabolism trials were conducted with 10 wethers equipped with ruminal, abomasal, and ileal cannulae to evaluate digestion of ensiled broiler litter (EBL), deepstacked broiler litter (DBL), and composted broiler litter (CBL). Wethers were fed a low protein (6.3% CP) basal diet alone or supplemented to 10.3% CP with EBL, DBL, CBL or soybean meal (SBM). All diets were formulated to be isoenergetic (56% TDN, DM basis). Apparent digestibilities of DM, OM, and ADF were not affected (p<0.05) by diet, but digestibility of CP was improved (p<0.05) by N supplementation. Apparent digestibility of CP was lower (p<0.05) for diets supplemented with CBL and DBL than for diets supplemented with SBM and EBL. Ruminal $NH_3$ concentration was 20 to 24 mg/dl at 2 h after feeding litter-supplemented diets compared with 13 mg/dl for SBM. Abomasal N, $NH_3$ N, and nonammonia N flows were increased (p<0.05) by N supplementation, whereas microbial N flow was not influenced (p<0.05) by diet. Compared with SBM and EBL, undegraded dietary CP flow to the abomasum tended to be greater (p<0.1) when wethers were fed DBL and CBLsupplemented diets. Retention of N (g/d) also was greater (p<0.05) due to greater (p<0.05) N intake and lower (p<0.05) urinary N excretion when wethers were fed diets supplemented with litter (especially EBL) vs. SBM. Overall, characteristics of ruminal fermentation and digestion indicated that broiler litter N was utilized efficiently by wethers, but ensiling may be preferable to deepstacking or composting.

• Animal cells and systems
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• v.2 no.3
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• pp.333-339
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• 1998

Litter decomposition is a key process in energy flow and nutrient cycling in the freshwater littoral zone, and is regulated by physicochemical properties of litters. Using a litterbag method, we compared the decomposition rates of 16 different litter types from 10 plant species of the emergent macrophytes for one year in the littoral zone of the Paltangho Reservoir, Korea. The regression analysis fitted to the various decomposition models showed that mass loss of the litters with time best fitted an asymptotic function. The litters of the emergent macrophytes were composed of two compartments, labile and refractory. The macrophytic litters showed a great variety in decomposition dynamics depending on sources of litters. The labile compartment of the initial litter mass was in a wide range between 18% and 99%, and their decomposition rates varied from 0.0037 to 0.0131 day-1. The decomposition processes of the emergent macrophytes were determined by the relative amounts of the labile and refractory compartments and by the decomposition rate of the habile one in the littoral zone.

• Journal of Plant Biology
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• v.25 no.3
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• pp.123-133
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• 1982

The tropic structure and the function of a small pone ecosystem under the tree stand were studied in terms of energy flow. About 28% of total solar radiation was intercepted by the tree canopy over the pond. Primary producers converted 1.1%(3,382 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$) of solar radiation (320,000 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$) into gross primary production. The amount of energy availble to the pond snail was 1,683 kcal.m-2.y-1 of the net production by primary producers and 1,033 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$ of the litter fallen into the pond. The amount of gross secondary production by the pond snail was 245 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$. Judging from these, supply of both net primary production and the litter was indispensable for the maintenance of the pond ecosystem. The total amont of energy as gross primary production plus litter was 4,415 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$(100%). Since the total respiration loss was calculated to be 1,917 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$(43.4%), the rate of energy accumulation in the pond estimated to 56.6%.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.263-273
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• 2015

We estimated the global inflow and stock of plastic marine debris. In South Korea, we estimated that the annual inflow of plastic marine debris (72,956 tons) was about 1.4% of annual plastics consumption (5.2 million tons) in 2012. By applying this 1.4% ratio to global plastics production from 1950 to 2013, we estimated that 4.2 million tons of plastic debris entered the ocean in 2013 and that there is a stock of 86 million tons of plastic marine debris as of the end of 2013, assuming zero outflow. In addition, with a logistic model, if 4% of petroleum is turned into plastics, the final stock of plastic marine debris shall be 199 million tons at the end. As the inflow and the stock are different units of measurement, better indicators to assess the effectiveness of inflow-reducing policies are needed. And, as the pollution from plastic marine debris is almost irreversible, countermeasures to prevent it should be valued more, and stronger preventive measures should be taken under the precautionary principle. As this is a preliminary study based on limited information, further research is needed to clarify the tendency of inflow and stock of plastic marine debris.

• Asian Journal of Turfgrass Science
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• v.11 no.4
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• pp.281-288
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• 1997

This study was performed to find out the mineral cycles of sulphur in dynamic grassland ecosystems in a steady state condition at the northwest side on Mt. Kwanak. The experimental results may be summarized on the communities of a Zoysia japonica and a Miscanthus sinensis as follows. As compared with some properties of the surface soils among two semi-natural grasslands, sulphur war greater quantity in a Miscanthus sinensis than in a Zoysia japonica on Mt. Kwanak . For the case of steady production and release, the raion of annual mineral production to the amount accumulated on the top of mineral soil in a steady state provides the estimates of release constant k. The release constants on sulphur of the litter were 0.54 in a Zoysia japonica and 0.36 in a Miscanthus sinensis grassland. The half times of S required for the release or accumulation of the litter on the grassland were 1.28 years in a Zoysia japonica and 1.93 years in a Miscauthus sinensis The amounts of annual cycles for sulphur in the grassland ecosystem under the steady-state conditions were 20.65g /$m^2$ in a Zoysia japonica and 26.28g /$m^2$ in a Miacanthus sinensis grassland. Key words: Zoysia japonica Miscanthus sinensis Mt. Kwanak, Sulphur, Mineral cycles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.10
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• pp.1020-1026
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• 2012

This paper proposes a new type of high-frequency directional valve controlled by the piezostack actuator associated with displacement amplifier. As a first step, a dynamic model of directional valve which can operate at 200 Hz with a flow rate of 12 litter/min is derived by considering pressure drop and flow force. As a second step, an appropriate piezostack is selected by considering actuation force as well as field-dependent displacement. Subsequently, in order to control spool displacement and flow rate a proportional-derivative(PD) controller is designed based on the 3rd-order valve system. Control performances such as sinusoidal trajectory tracking of the spool displacement in time domain are evaluated. In addition, the field-dependent flow rate is also presented to verify the required performance of the valve system.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.2
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• pp.178-184
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• 1997

Vocal nodule due to vocal hyperfunction is one of the representative chronic diseases of vocal folds, and it can be cured by surgical movement, and/or voice therapy. The present study is, focusing on the latter, to compare the acoustic and aerodynamic results of the pretreatment with those of posttreatment, and then to investigate the objective date on the efficiency of the voice therapy for the patients with vocal nodules. 11 females(age : 7-49) and 5 males(age : 8-40), total 16 patients wi vocal nodules treated by voice therapy were participated as subjects. Six measurements and comparisons of pretreatment and posttreatment of the results were performed : litter, shimmer, and noise-to-harmonic ratio as acoustic analyses ; maximum phonation time, mean flow rate, and the subtraction of mean flow rate from maximum flow rate as aerodynamic analyses. As a result, 14 of 16 subjects showed improvement at more than 4 of 6 measurements, and in group data, every measurements of posttreatment was improved significantly than the pretreatment. On the whole, the improvement of aerodynamic aspects was more statistically significant than that of acoustic ones.