• Korean Journal of Environment and Ecology
• /
• v.25 no.6
• /
• pp.893-902
• /
• 2011

The purpose of this study was to survey structures and growth conditions of Pinus densiflora village groves, and to establish management strategies for their desirable growth and conservation. Twelve village groves were selected in western Gangwon province for the study. The age of the study groves ranged from 50 to 200 years. Average dbh (diameter at breast height) and density of trees for each study grove were 27~52cm and 0.5~9.3 trees/$100m^2$, respectively. Soil environments were favorable to Pinus densiflora growth in the majority of the study groves, but 2 study groves with sandy soils showed considerably poor nutrient contents. Low tree vitality was found in some of the study groves due to poor conditions of root growth from soil fill and trampling. There were detachment of cambial tissue and damage of stem cavity at 6 study groves, which were caused by artificial injury, careless pruning, and frost damage. Light disease damage by Rhizosphaera kalkhoffii and phomopsis blight were found at 6 study groves. Light pest damage by Thecodiplosis japonensis was also found at 6 study groves, but the pest damage at 2 study groves was relatively considerable. Thus, major factors limiting normal growth of Pinus densiflora village groves were infertility, soil fill and trampling, stem damage, and disease and pest. Desirable management strategies were explored to solve growth-related problems and to conserve the study groves. The management strategies included fertilization of organic matter and lime, removal of soil fill, soil plowing and graveling, wood-trail installation or woodchip mulching, supply of wood fences and protective frames, surgical operation for damaged stems, vitality enhancement, and trunk injection to improve growth environments or control stem damage and disease/pest.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.834-840
• /
• 2018

In this study, the characteristics of air pollutant emissions from ships' engines have been investigated by conducting E2 and E3 cycle mode tests. A engine 360Ps (Doosan L126TIH engine) and 400kW dynamometer Horiba-Schenck were utilized for engine tests. The FTIR analyzer and SPC were used to measure exhaust gas (NOx, SOx etc.) and PM (particulate matter), respectively. The results showed that the emissions of THC and CO produced from engine were increased with the increase of sulfur content in fuel oils at E2 and E3 cycle modes. The kinetic viscosity of the fuel increased as the sulfur content of the fuel increased, thereby the specific fuel oil consumption (SFC) of the engine improved. This result is considered to be due to improved combustion conditions due to increased average diameters of sprayed particles and due to increased kinetic viscosity under constant fuel injection pressure in this study. In the case of NOx emission, this study showed no significant change in amount of sulfur content.

• Journal of Environmental Science International
• /
• v.12 no.1
• /
• pp.47-54
• /
• 2003

This paper have examined the optimum combination of SNCR and SCR by varying SNCR injection temperature and NSR ratio along with SCR space velocity. NOx reduction experiments using a SNCR/SCR combined process have been conducted in simple NO/NH$_3$/O$_2$ gas mixtures. Total gas flow rate was kept constant 4 liter/min throughout the SNCR and SCR reactors, where initial NOx concentration was 500 ppm in the presence of 5% O$_2$. Commercial catalyst, sulfated V$_2$O$\_$5/-WO$_3$/TiO$_2$, was used for SCR NOx reduction. The residence time and space velocity were around 1.67 sec, 2,400 h$\^$-1/ and 6,000 h$\^$-1/ in the SNCR and SCR reactors, respectively. SNCR NOx reduction effectively occurred in a temperature window of 900-950$^{\circ}C$. About 88% NOx reduction was achieved with an optimum temperature of 950$^{\circ}C$ and NSR=1.5. SCR NOx reduction using commercial V$_2$O$\_$5/-WO$_3$-SO$_4$/TiO$_2$ catalyst occurred in a temperature window of 200-450$^{\circ}C$ 80-98% NOxreduction was possible with SV=2400 h$\^$-1/ and a molar ratio of 1.0-2.0. A SNCR/SCR(SV=6000 h$\^$-1/) combined process has shown same NOx reduction compared with a stand-alone SCR(SV=2400 h$\^$-1/) unit process of 98% NOx reduction. The NH$_3$-based chemical could routinely achieve SNCR/SCR combined process total NOx reductions of 98% with less than 5 ppm NH$_3$ slip at NSR ranging from about 1.5 to 2.0, SNCR temperature of 900$^{\circ}C$-950$^{\circ}C$, and SCR space velocity of 6000 h$\^$-1/. Particularly, more than 98% NOx reduction was possible using the combined process under the conditions of T$\_$SNCR/=950$^{\circ}C$, T$\_$SCR/=350$^{\circ}C$, 5% O$_2$, SV=6000 h$\^$-1/ and NH$_3$/NOx=1.5. A catalyst volume was about three times reduced by SNCR/SCR combined process compared with SCR process under the same controlled conditions.

• Analytical Science and Technology
• /
• v.8 no.2
• /
• pp.215-220
• /
• 1995

A simple, efficient and sensitive method was described for the simultaneous determination of catecholamine, indoleamine and related metabolites from the homogenates of the rat brain striatum by HPLC-ECD. The optimum mobile phase on a reverse phase $C_{18}$ column was 35mM sodium acetate buffer(included 10mM citric acid, 0.13mM $Na_4EDTA$, 0.58mM SOS, pH3-4):MeOH=85:15. The column temperature was $30^{\circ}C$. Dopamine(DA), 3, 4-dihydroxyphenyl acetic acid(DOPAC), homovanilic acid(HVA), 5-hydroxyindole acetic acid(5-HIAA), serotonin(5-HT) and noradrenaline(NA) could be separated and analysed to very small amount. The detection limits of this method were 2~10pg per injection for all components. The effects of age and sex of rat on the contents of the catecholamines and their metabolites in rat brain striatum were studied. The levels of DA and 5-HT contents of the 7 week old female rats were higher than those of the 7 week old male rats. As the age of rat increases, the contents of DOPAC increased significantly.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.8
• /
• pp.755-760
• /
• 2010

In this study, we mainly focused on the PM (Particulate Matter) emission characteristics of a diesel engine. To analyze particle behavior in the tail-pipe, particle emission was measured on the engine-out (downstream of turbocharger), each upstream and downstream both of DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). Moreover, particle emission contours on each sampling point were constructed. The reduction efficiency of particle number concentration and mass through the DOC and DPF was studied. Parameters such as EGR (Exhaust Gas Recirculation) and the main injection timing were varied in part load conditions and evaluated using the engine-out emissions. The DMS500 (Differential Mobility Spectrometer) was used as a particle measurement instrument that can measure particle concentrations from 5 nm to 1000 nm. Nano-particles of sizes less than 30 nm were reduced by oxidation or coagulated with solid particles in the tail-pipe and DOC. The DPF has a very high filtration efficiency over all operating conditions except during natural regeneration of DPF.

• Journal of the Korean Vacuum Society
• /
• v.19 no.5
• /
• pp.377-384
• /
• 2010

Many routes have been developed for the synthesis of signle-walled carbon nanotubes (SWCNTs). We spun fibers of SWCNTs directly from vertical furnace using a liquid source of carbon and an iron-contained molecule. The solution was prepared by ethanol as a carbon source, in which ferrocene as a catalyst, thiophene were dissolved. It was then injected from the top of the furnace into hot zone with hydrogen as a carrier gas. We successfully synthesized high-quality SWCNTs by adjusting the various experimental conditions, such as concentration of ferrocene, solution injection rate, concentration of thiophene, and hydrogen flow rate. Measurement of Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were carried out to find the optimized conditions. The synthesized SWCNTs (1.16~1.64 nm) appeared a bundle structure and well-aligned parallel to the direction of furnace. These results also provide an simple way for high-quality SWCNTs mass production and fabricating direct spining SWCNTs fiber. It will allow one-step production of SWCNTs fiber with potentially excellent properties and wide-range applications.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.5
• /
• pp.775-786
• /
• 2017

Monitoring sediment flux is crucial especially for maintaining river systems to understand morphological behaviors. Recently, hydroacoustic backscatter (or SNR) as a surrogate to empirically estimate suspended sediment concentration has been increasingly highlighted for more efficient acquisition of sediment dataset, which is difficult throughout direct sediment sampling. However, relevant contemporary researches have focused on wide range solution applicable for large natural rivers where H-ADCPs with relatively low acoustic frequency have been widely utilized to seamlessly measure streamflow discharge. In this regard, this study aimed at investigating hydroacoustical characteristics based on a very recently released H-ADCP (SonTek SL-3000) with high acoustic frequency of 3 MHz in order to capitalize its capacity to be applied for suspended sediment monitoring in laboratory conditions. SL-3000 was tested in a laboratory flume to collect SNR in conjunction with LISST-100X for actual sediment concentration and particle distribution in both sand and silt sediment injection in various amount. Conventional algorithms to correct signal attenuations for water and sediment were carefully tested to validate whether they can be applied for SL-3000. As result of analyzing the SNR-SSC correlation trand, through further study in the future, it is confirmed that SSC can be observed indirectly by using the SNR.

• International Journal of Oral Biology
• /
• v.40 no.3
• /
• pp.117-125
• /
• 2015

The present study investigated the role of central $GABA_A$ and $GABA_B$ receptors in orofacial pain in rats. Experiments were conducted on Sprague-Dawley rats weighing between 230 and 280 g. Intracisternal catheterization was performed for intracisternal injection, under ketamine anesthesia. Complete Freund's Adjuvant (CFA)-induced thermal hyperalgesia and inferior alveolar nerve injury-induced mechanical allodynia were employed as orofacial pain models. Intracisternal administration of bicuculline, a $GABA_A$ receptor antagonist, produced mechanical allodynia in naive rats, but not thermal hyperalgesia. However, CGP35348, a $GABA_B$ receptor antagonist, did not show any pain behavior in naive rats. Intracisternal administration of muscimol, a $GABA_A$ receptor agonist, attenuated the thermal hyperalgesia and mechanical allodynia in rats with CFA treatment and inferior alveolar nerve injury, respectively. On the contrary, intracisternal administration of bicuculline also attenuated the mechanical allodynia in rats with inferior alveolar nerve injury. Intracisternal administration of baclofen, a $GABA_B$ receptor agonist, attenuated the thermal hyperalgesia and mechanical allodynia in rats with CFA treatment and inferior alveolar nerve injury, respectively. In contrast to $GABA_A$ receptor antagonist, intracisternal administration of CGP35348 did not affect either the thermal hyperalgesia or mechanical allodynia. Our current findings suggest that the $GABA_A$ receptor, but not the $GABA_B$ receptor, participates in pain processing under normal conditions. Intracisternal administration of $GABA_A$ receptor antagonist, but not $GABA_B$ receptor antagonist, produces paradoxical antinociception under pain conditions. These results suggest that central GABA has differential roles in the processing of orofacial pain, and the blockade of $GABA_A$ receptor provides new therapeutic targets for the treatment of chronic pain.

• Korean Journal of Construction Engineering and Management
• /
• v.12 no.2
• /
• pp.111-120
• /
• 2011

High-rise buildings have recently increased over the residential, commercial and office facilities, thus an understanding of construction cost for high-rise building projects has been a fundamental issue due to enormous construction cost as well as unpredictable market conditions and fluctuations in the rate of inflation by long-term construction periods of high-rise projects. Especially, recent violent fluctuations of construction material prices add to problems in construction cost forecasting. This research, therefore, develops a time-series model with the Box-Jenkins methodologies and material prices time-series data in Korea in order to forecast future trends of unit prices of required materials. BIM (Building Information Modeling) approaches are also used to analyze injection time of construction resources and to conduct quantity takeoff so that total material price can be forecasted. Comparative analysis of Predictability of tentative ARIMA (Autoregressive Integrated Moving Average) models was conducted to determine optimal time-series model for forecasting future price trends. Proposed BIM based time series forecasting model can help to deal with sudden changes in economic conditions by estimating future material prices.

• Journal of the Korean Institute of Gas
• /
• v.19 no.4
• /
• pp.1-7
• /
• 2015

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions of automotive had many problem that cause of ambient pollution, health effects. Based on various test modes and ambient conditions, this paper discusses the characteristics of LPG on exhaust emissions and greenhouse gases. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of vehicle test mode and ambient condition, exhaust emission, greenhouse gas emission was analyzed.