• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.22-28
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• 2011

With the increasing cultivation of acid-loving plants such as blueberries, the artificial acidification of soils is frequently required. This research was conducted to determine the application rates of elemental sulfur (S) required in the soil acidification for blueberry cultivation. Laboratory incubation experiment was conducted to acidify three arable soils (pH 6-7) of different texture to pH 4.5-5.0 by the addition of varying amounts of elemental S. All rates of elemental S addition reduced soil pH, although the efficacy of acidification was related to the application rate and soil characteristics. pH reduction was slow in sandy loam soil, and the final equilibrium pH was obtained after 60, 43, and 30 days of incubation in sandy loam, loam, and silty clay, respectively. Although the final pHs obtained after 93 days of incubation were not significantly different among the three soils, the equilibrium pH was relatively higher in soil of higher clay content in the application rates of 1.5-2.0 g S $kg^{-1}$ soil. The estimated amounts of elemental S required in lowering pH to 4.5-5.0 were 0.59-1.01, 0.67-1.03, and 0.53-0.88 g S $kg^{-1}$ for sandy loam, loam, and silty clay, respectively. The lowest estimated amount of elemental S in the acidification of silty clay soil was attributable to the low organic matter content. For clay soils containing optimum level of organic matter, the application rates of elemental S should be much higher than those values estimated in this research. Soil acidification did not significantly increase the available concentrations of Ca, Mg and K. Extractable Cu and Zn was not greatly affected by the acidification, but extractable Fe, Mn, and Al in the acidified soils were higher than those found in non-acidified soils. Such increases in solubility are attributable to the dissolution of oxides and hydroxides of the elements.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.1013-1021
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• 2017

Exposure to Diesel Particulate Matter (DPM) potentially causes adverse health effects (e.g. respiratory symptoms, lung cancer). Due to a lack of data on Elemental Carbon (EC) exposure levels in underground copper ore mining (unlike other underground mining industries such as non-metallic and coal mining), this case study aims to provide individual miners' EC exposure levels, and information on their work practices including use of personal protective equipment. EC measurement was carried out during different work activities (i.e. drilling, driving a loader, plant fitting, plant operation, driving a Specialized Mining Vehicle (SMV)) as per NIOSH Method 5040. The copper miners were working 10 h/day and 5 days/week. This study found that the most significant exposures to EC were reported from driving a loader (range $0.02-0.42mg/m^3$). Even though there were control systems (i.e. water tanks and DPM filters) on the diesel vehicles, around 49.5% of the results were over the adjusted recommendable exposure limit ($0.078mg/m^3$). This was probably due to: (1) driver's frequently getting in and out of the diesel vehicles and opening the windows of the diesel vehicles, and (2) inappropriate maintenance of the diesel vehicles and the DPM control systems. The use of the P2 type respirator provided was less than 19.2%. However, there was no significant difference between the day shift results and the night shift results. In order to prevent or minimize exposure to EC in the copper ore mine, it is recommended that the miners are educated in the need to wear the appropriate respirator provided during their work shifts, and to maintain the diesel engine and emission control systems on a regular basis. Consideration should be given to a specific examination of the diesel vehicles' air-conditioning filters and the air ventilation system to control excessive airborne contaminants in the underground copper mine.

• Journal of Environmental Health Sciences
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• v.33 no.6
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• pp.479-487
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• 2007

[ $PM_{2.5}$ ], particulate matter less than 2.5 um in a diameter, can penetrate deeply into the lungs. Exposure to $PM_{2.5}$ has been associated with increased hospital visits for respiratory aliments as well as increase mortality. $PM_{2.5}$ is a byproduct of combustion processes and as such has a complex composition including a variety of metallic elements, inorganic and organic compounds as well as biogenic materials (microorganisms, proteins, etc). In this study, the average concentrations of fine particulates $PM_{2.5}$ have been measured simultaneously in Asan and Seoul, Korea, by using particulate matter portable sampler from September 2001 to August 2002. Sample collection filters were analyzed by ICP-OES to determine the concentrations of metallic elements (As, Ni, Fe, Cr, Cd, Cu, Pb, Zn, Si). Annual mean $PM_{2.5}$ concentrations in Asan and Seoul were 37.70 and $45.83\;{\mu}g/m^3$, respectively. The highest concentrations of $PM_{2.5}$ were found in spring season in both cities and the concentrations of measured metallic elements except As in Asan were higher than those in Seoul, suggesting that yellow dust in spring could affect $PM_{2.5}$ concentrations in Asan rather than Seoul. The correlation coefficients of Pb and Zn were 0.343 for Asan and 0.813 for Seoul during non-yellow dust condition, suggesting that Pb and Zn were influenced with the same sources. The correlation coefficients between Si and Fe in the fine particulate mode were 0.999 (Asan) and 0.998 (Seoul) during yellow dust condition. It was suggested that these two elements were impacted by soil-related transport from China during the yellow dust storm condition.

• Journal of The Korean Astronomical Society
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• v.40 no.3
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• pp.67-82
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• 2007

The basic building block of solar filaments/prominences is thin threads of cool plasma. We have studied the spectral properties of velocity threads, clusters of thinner density threads moving together, by analyzing a sequence of $H{\alpha}$ images of a quiescent filament. The images were taken at Big Bear Solar Observatory with the Lyot filter being successively tuned to wavelengths of -0.6, -0.3, 0.0, +0.3, and +0.6 ${\AA}$ from the centerline. The spectra of contrast constructed from the image data at each spatial point were analyzed using cloud models with a single velocity component, or three velocity components. As a result, we have identified a couple of velocity threads that are characterized by a narrow Doppler width($\Delta\lambda_D=0.27{\AA}$), a moderate value of optical thickness at the $H{\alpha}$ absorption peak($\tau_0=0.3$), and a spatial width(FWHM) of about 1". It has also been inferred that there exist 4-6 velocity threads along the line of sight at each spatial resolution element inside the filament. In about half of the threads, matter moves fast with a line-of-sight speed of $15{\pm}3km\;s^{-1}$, but in the other half it is either at rest or slowly moving with a line-of-sight velocity of $0{\pm}3km\;s^{-1}$. It is found that a statistical balance approximately holds between the numbers of blue-shifted threads and red-shifted threads, and any imbalance between the two numbers is responsible for the non-zero line-of-sight velocity determined using a single-component model fit. Our results support the existence not only of high speed counter-streaming flows, but also of a significant amount of cool matter either being at rest or moving slowly inside the filament.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.484-489
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• 2012

The objective of this work presented here was focused on analysis of particulate matter and nitrogen oxide characteristics in ESC test mode from heavy-duty diesel engine installed on-road vehicles applicable to prime propulsion engine for marine vessels. The authors confirmed that a large quantity particulate matter were emitted in high power density condition, nitrogen oxide characteristics were dependent on exhaust gas temperature. Particulate matters were reduced by 1/100~1/1,000 times in post DPF with test modes but filtration efficiency was decreased in the engine power fluctuation. In the case of the high speed and power condition, the exhaust level of particulate matters was increased according to increment of temperature of gas flowing into DPF. The orders of magnitude for particle concentration levels from the analysis of size distribution of particulate matters of test engine was different. Both emitting nano-sized particles below 100nm regardless of DPF and non-DPF.

• Journal of Preventive Medicine and Public Health
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• v.48 no.3
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• pp.151-169
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• 2015

Objectives: The deleterious effects of air pollution on various health outcomes have been demonstrated. However, few studies have examined the effects of air pollution on liver enzyme levels. Methods: Blood samples were drawn up to three times between 2008 and 2010 from 545 elderly individuals who regularly visited a community welfare center in Seoul, Korea. Data regarding ambient air pollutants (particulate matter ${\leq}2.5{\mu}m$ [$PM_{2.5}$], nitrogen dioxide [$NO_2$], ozone [$O_3$], carbon monoxide, and sulfur dioxide) from monitoring stations were used to estimate air pollution exposure. The effects of the air pollutants on the concentrations of three liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and ${\gamma}$-glutamyltranspeptidase [${\gamma}$-GTP)]) were evaluated using generalized additive and linear mixed models. Results: Interquartile range increases in the concentrations of the pollutants showed significant associations of $PM_{2.5}$ with AST (3.0% increase, p=0.0052), ALT (3.2% increase, p=0.0313), and ${\gamma}$-GTP (5.0% increase, p=0.0051) levels; $NO_2$ with AST (3.5% increase, p=0.0060) and ALT (3.8% increase, p=0.0179) levels; and $O_3$ with ${\gamma}$-GTP (5.3% increase, p=0.0324) levels. Significant modification of these effects by exercise and alcohol consumption was found (p for interaction <0.05). The effects of air pollutants were greater in non-exercisers and heavy drinkers. Conclusions: Short-term exposure to air pollutants such as $PM_{2.5}$, $NO_2$, and $O_3$ is associated with increased liver enzyme levels in the elderly. These adverse effects can be reduced by exercising regularly and abstinence from alcohol.

• Korean Journal of Organic Agriculture
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• v.5 no.2
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• pp.117-128
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• 1997

This study was carried out to investigate the amounts of voluntary intake, digestibility and nitrogen retention in Korean native goats (KNG) fed agricultural by-products containing rice straw (RS) and apple pomace (AP) and to obtain a basic information for establishing the feeding system of KNG. The result are as follows. 1. Among the chemical composition of experimental diets, the highest values in crude protein (CP ; 18.6%) and crude ash contents (10.7%) were observed in alfalfa hay. Those of RS+AP treatment were significantly low 6.0 and 4.8%, respecitively. Acid detergent fiber (ADF), ether extract and non-structural carbohydrate (NSC) contents were shown an adverse tendency. 2. Dry matter (DM) intakes per day in KNG fed RS+commercial diet (CD), RS+AP and RS+AP+CD were significantly lower (P<0.05) 210.3, 228.3, respectively than 358.1g in alfalfa hay. 3. DM intakes per basal weight expressed as DM g/kg of BW0.75 and DM g/kg of BW(%) were highest (P<0.05) 60.5g and 3.3%, respectively in KNG fed alfalfa hay, any other treatments showed 35.6 to 42.5g and 2.0 to 2.3%, respectively and this result was similar to those of DM intake per day. 4. Digestibilities of DM, organic matter, CP, ADF, neutral detergent fiber (NDF). crude ash and ether extract in alfalfa hay and RS+AP+CD treatment were significantly higher (P<0.05) than RS+CD treatment. Those of CP, ADF and NDF of RS+AP treatment in not significantly different with these treatments. 5. NSC digestibility was higher in alfalfa hay (66.7%) than those of other treatments (44.2~52.0% ; P<0.05). 6. Nitrogen retentions expressed as N retention(g) and N retention (%) in KNG were highest (P<0.05) 0.6g and 15.6%, respectively in RS+AP+CD treatment and RS+CD treatment was lowest (P<0.05) -06g and -21.4%, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.4
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• pp.467-473
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• 2008

Natural organic matter (NOM) removal by physico-chemical adsorption and biological oxidation was investigated in five slow sand filters with different media depths. Non-purgeable dissolved organic carbon(NPDOC) and $UV_{254}$ absorbance were measured to evaluate the characteristics of NOM removal at different filter depths. Removal efficiency of NOM was in the range of 10-40% throughout the operation time. At start-up of the filters packed with clean sand media, NOM was probably removed by physico-chemical adsorption on the surface of sand through the overall layer of filter bed. However, when Schumutzdecke layer was built up after 30 days operation, the major portion of NPDOC was removed by biological oxidation and/or bio-sorption in lower depth above 50 mm. NOM removal rate in the upper 50 mm filter bed was $0.82hr^{-1}$. It was about 20 times of the rate($0.04hr^{-1}$) in the deeper filter bed. Small portion of NPDOC could be removed in the deeper filter bed by both bio-sorption and biodegradation. SEM analysis and VSS measurement clearly showed the growth of biofilm in the deeper filter bed below 500 mm, which possibly played an important role in the NOM removal by biological activity besides the physco-chemical adsorption mechanism

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.206-213
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• 2011

An experiment was conducted to evaluate the effect of replacing barley and soybean meal in finishing diets with sesame hull (SH) on growth performance, digestibility, and carcass characteristics of Black goat kids. Twenty-one Black goat kids were assigned randomly to 0%, 10%, or 20% SH diets (7/diet). The study lasted for 63 d. Intakes of dry matter (DM), organic matter (OM), and crude protein (CP) of kids fed the 10% diet were greater (p<0.05) than for the 0% and 20% SH diets (p<0.10). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) intakes were highest (p<0.05) for kids fed the 10% SH diet when compared to 0% and 20% SH diets. Ether extract (EE) intake was greater (p<0.05) for kids fed 10% and 20% SH diets when compared to 0% SH. Digestibilities of DM, OM, CP, NDF, and ADF were similar among all diets. However, sesame hull inclusion increased (p<0.05) EE digestibility. Final body weight, total gain, average daily gain (ADG), and feed conversion ratio were comparable among all diets. Cost of gain was lower (p<0.05) in kids fed 20% SH than the 0% SH diet, while there was no difference between the 10% SH diet and the other two diets. Dressing percentage, hot and cold carcass weights, non-carcass components, carcass cut weights, and meat quality parameters were not influenced by SH. Total fat percentage in the leg was greater (p<0.05) on 0% SH than on the 10% SH diet. Results of this study demonstrated that inclusion of sesame hull at levels of 10 or 20% did not influence the performance of Black goat kids, but the cost of gain was lower.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.2
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• pp.107-114
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• 1988

Six steers of each breed type, Hereford ($H{\times}H$), Brahman ($B{\times}B$) and Brahman $\times$ Hereford ($B{\times}H$) were ranked on liveweight and allocated to three treatments, basal hay diet (Basal), Basal plus 1 kg/head/day of cottonseed meal (Basal + CSM) and Basal plus 1 kg/head/day of formaldehyde-treated sunflower meal, $Norpro^{(R)}$ (Basal + NPO). The hay was made from a pasture based predominantly on carpet grass (Axonopus affinus) growing in subtropical New South Wales, and had an estimated organic matter digestibility of 52% and a nitrogen (N) content of 7.8 g/kg dry matter (DM). The steers were accustomed to the Basal diet over 15 days and supplements offered over 42 days. Intake of the basal hay diet by steers was not increased by supplementation. When intakes were adjusted for differences between breed types in liveweight the $B{\times}H$ steers ate 25% (P<0.01) more hay than $H{\times}H$ steers (6.3 V 5.0 kg/head/d) and $B{\times}B$ steers ate 8% less hay than $H{\times}H$ steers. Supplementation significantly (P<0.01) increased liveweight gain during the experiment, being ($g/head/d\;{\pm}\;s.e.d.$) 290, 770 and $795{\pm}118$ respectively for Basal, Basal + NPO and Basal + CSM. There was no difference between supplements in the liveweight gain of steers nor between steers of different genotypes. However, there was a significant interaction (P<0.01) between breeds and treatments such that $B{\times}B$ steers gained most on the basal diet but least of the breed types when supplemented. The estimated non-degradeable fraction of N in the protein meals was 58.5 and 44.5%, respectively for NPO and CSM. Both meals increased (P<0.01) plasma urea N and rumen ammonia N concentrations.