• Journal of Soil and Groundwater Environment
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• v.21 no.5
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• pp.8-15
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• 2016

Bioremediation, which uses microbes to degrade most organic pollutants in soil and groundwater, can be used in solving environmental issues in various polluted sites. In this research, a wind-driven bioventing system is built to degrade about 20,000 mg/kg of high concentration diesel pollutants in soil-pollution mode. The wind-driven bioventing test was proceeded by the bioaugmentation method, and the indigenous microbes used were Bacillus cereus, Achromobacter xylosoxidans, and Pseudomonas putida. The phenomenon of two-stage diesel degradation of different rates was noted in the test. In order to interpret the results of the mode test, three microbes were used to degrade diesel pollutants of same high concentration in separated aerated batch-mixing vessels. The data derived thereof was input into the Haldane equation and calculated by non-linear regression analysis and trial-and-error methods to establish the kinetic parameters of these three microbes in bioventing diesel degradation. The results show that in the derivation of μ_m (maximum specific growth rate) in biodegradation kinetics parameters, K_s (half-saturation constant) for diesel substance affinity, and K_i (inhibition coefficient) for the adaptability of high concentration diesel degradation. The K_s is the lowest in the trend of the first stage degradation of Bacillus cereus in a high diesel concentration, whereas K_i is the highest, denoting that Bacillus cereus has the best adaptability in a high diesel concentration and is the most efficient in diesel substance affinity. All three microbes have a degradation rate of over 50% with regards to Pristane and Phytane, which are branched alkanes and the most important biological markers.

• Tribology and Lubricants
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• v.22 no.4
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• pp.190-195
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• 2006

A simple and effective analysis method is presented for gaining a complete transient temperatures on the internal and external surfaces of a 40 mm gun tube subjected to a series of rapid firings. Two series of temperature data for both Hs and As were measured by using two rapid response k-type surface thermocouples near the firing origin and the muzzle. With other available temperature data, patterns of temperature variations of the gun tube as a function of time variable were driven through complete evaluations of the data. It is found that overall temperature gradients which increase exponentially toward saturation temperature, actually consist of a series of linear temperature gradients corresponding to the firing sequences. Under the similar firing sequences, patterns of temperature variations fur both the surface temperatures near the chamber and those near the muzzle were found to have linear temperature gradients with different values and the same response frequencies, i.e. they had peaks and lows in temperatures at the same time. The resultant complete temperature data can be used as the fundamental bases for analysis of thermoelastic properties of the materials such as thermal strain and stress, and f3r the prediction of cannon tube life-time through calculation of wear rate.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.119-131
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• 2020

A numerical model was developed using COMSOL Multiphysics to evaluate groundwater flow that causes radionuclide migration in the unsaturated zone of a near-surface disposal facility, which is considered as a domestic low and an intermediate-level radioactive waste disposal facility. Each scenario was modeled by constructing a two-dimensional domain that included the disposal vault, backfill, disposal cover, and unsaturated aquifer. A comparison of the continuous and intermittent rainfall conditions exhibited no significant difference in any of the factors considered except the wave pattern of water saturation. The input data, such as porosity and residual water content of the unsaturated aquifer, were observed to not have a significant effect on the groundwater flow. However, the hydraulic conductivity of the unsaturated aquifer was found to have a significant effect on the groundwater flow. Therefore, it is necessary to assess the hydraulic conductivity of an unsaturated aquifer to determine the extent of groundwater infiltration into the disposal vault.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2185-2191
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• 2015

With the advance of the environment where we can get various multimedia contents, adult image detection has become an important issue these days. In this paper, we suggest a method of robustly detecting navel areas from input images which can be usefully utilized in adult image detection. The suggested algorithm first extracts face regions and extracts candidate nipple areas using a nipple map. Our method then selects only actual nipple regions by filtering candidate areas with geometrical features and an average nipple filter. Subsequently, the method robustly detects navel areas by using the structural relation with the nipple areas and applying edge and saturation images. Experimental results show that the suggested algorithm can effectively detect navel regions.

• Journal of IKEEE
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• v.22 no.2
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• pp.362-368
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• 2018

This paper has implemented a mutual conversion system that mutually converts between body motion signals and both visual and auditory signals. The present study is based on intentional synesthesia that can be perceived by learning. The Euler's angle was used in body movements as the output of a wearable armband(Myo). As a muscle sense, roll, pitch and yaw signals were used in this study. As visual and auditory signals, MIDI(Musical Instrument Digital Interface) signals and HSI(Hue, Saturation, Intensity) color model were used respectively. The method of mutual conversion between body motion signals and both visual and auditory signals made it easy to infer by applying one-to-one correspondence. Simulation results showed that input motion signals were compared with output simulation ones using ROS(Root Operation System) and Gazebo which is a 3D simulation tool, to enable the mutual conversion between body motion information and both visual and auditory information.

• Journal of Fisheries and Marine Sciences Education
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• v.6 no.1
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• pp.58-76
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• 1994

Heat transfer and pressure drop measurements are made on low integral-fin tubes in turbulent water flow condition. The integral-fin tubes investigated in this paper are nominally 19mm in diameter. Eight tubes have been used with trapezoidally shaped integral-fins having fin density from 748 to 1654 fpm and 10, 30 grooves. Plain tube having same diameter as finned tube is also tested for comparison. Experiments are carried out using R-11 as working fluid. The refrigerant condensates at a saturation state of $30^{\circ}C$ on the outside tube surface cooled by coolant. The amount of noncondensable gases present in the test loop is reduced to a negligible value by repeated purging. For a given heat input to the boiler and given cooling water flow rate, all test data are taken on steady state. The heat transfer loop is used for testing single long tubes and cooling water is pumped from a storage tank through filters and flowmeters to the horizontal test section where it is heated by steam condensing on the outside of the tube. The pressure drop across the test section is measured by means of pressure gauge and manometer. Each tube tested is cleaned with sodium dichromate pickling solution and well rinsed with water prior to installation in the test section. The results obtained in this study is as follows : 1. Based on inside diameter and nominal inside area, heat transfer of finned tube is enhanced up to 4 times as that of a plain tube at constant Reynolds number and up to 2 times at constant pumping power. 2. Friction factors are up to 1.6~2.1 times those of plain tube. 3. At a given Reynolds number, Nusselt number decrease with increasing pitch to diameter. 4. The constant pumping power ratio for low integral-fin tubes increase directly with the effective area to the nominal area ratio, and with the effective area diameter ratio.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.349-356
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• 2018

In this study, the synchronous control system is designed to restrain the speed difference generated between two propellers, namely, synchronous error in a dual electric propulsion system of unmanned surface vehicle, fish finder boat, etc. The control system based on coupling structure is composed of pre-filters and speed controllers for each propulsion system and a synchronous controller cross-coupled between two propulsion systems. The pre-filter and speed controller are designed in order that the propulsion system may follow the speed reference without overshoot and input saturation. And the synchronous controller is designed in consideration of damping and quickness of the synchronous controller system after analyzing effect of the skew disturbance and mismatched dynamic characteristics on synchronous error. Finally, the simulation results show that the designed control system is effective for elimination of synchronous error.

• Journal of Environmental Science International
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• v.9 no.1
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• pp.1-11
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• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1111-1121
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• 2015

Roundabouts face a congestion problem when there are unbalanced traffic conditions, especially during peak times. The congestion at roundabouts results in long delay times and low level of service. Some research has addressed congestion problems of the metering roundabout, however, few studies have focused on the congestion issues of the double signals metering roundabout. This research bridges this gap through analyzing the congestion issues of the Old Belair double signals roundabout in Adelaide. The research proposes a new analysis method based on a four-nodes intersection in order for double signals roundabout analysis to be carried out as follows: firstly, at the modeling stage, a connection of four individual intersections, adjustment of lane geometry, input of directional traffic volumes, priority and phase time set up are proposed. Secondly, for calibration, PFF, critical gap, follow-up headway and extra bunching values have been applied. The results from the analysis show that the new method is able to analyze the delay time, level of service, degree of saturation and allow for further analysis.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.103-109
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• 2005

This paper presents the design of a broadband hybrid mixer using dual-gate FET topology with a low-pass filter which improves return loss of output to isolate RF and LO signal. The low-pass filter shows the isolation with RF and LO signal of better than 40 dBc from 1.5 GHz to 5.5 GHz. The dual-gate mixer which has been designed by using cascade topology operates when the lower FET is biased in linear region and the upper FET is in saturation region. The input matching circuit has been designed to have conversion gain from 1.5 GHz to 5.5 GHz. The designed mixer with low-pass filter shows the conversion gain of better than 7 dB from 1.5 GHz to 5.5 GHz at the low LO power level of 0 dBm with the fixed IF frequency of 21.4 MHz.