• Current Research on Agriculture and Life Sciences
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• v.32 no.1
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• pp.1-9
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• 2014

In contrast to conventional microwaves, QRD (Quadratic Residue Diffusor) microwaves are a new energy-efficient technology that enhances the effect of sterilization based on changing the wavelength phase difference. Therefore, this study investigated the sterilization of wood using environmentally friendly and low energy consuming QRD microwaves. The results are as follows: for the QRD microwaves used in this study, the efficiency E = 5.75e0.32 S ($R^2$=0.908). Although the early water content was not constant, the average water content was 30.3% and after one week of natural drying, the water content was 22.6%, representing an average water content reduction of about 8%. When increasing the microwave level from 3 kW ~ 9 kW, the time taken for the temperature to increase was reduced. After the QRD microwave treatment, the wood samples showed no change in their flexural rigidity, compressive strength, or cleavage. The QRD microwave levels used in the experiments were 3, 5, 7, and 9 kW, where 9 kW was found to be the most efficient. Thus, for the purpose of eliminating nematodes and termites inside wood, a higher QRD microwave level was found to be more effective and energy efficient.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1391-1398
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• 2010

Reuse feasibility of MBR effluent of S Electronic Company's organic wastewater as a LCD process water was investigated by a $32m^3/d$ pilot-scale RO membrane process. The effects of operating pressure and permeate flux at constant 85% recovery of RO membrane process using MBR effluent were analyzed for transmembrane pressure and period for CIP by membrane fouling as well as rejection of TOC and conductivity. MBR effluent requires additional treatment to meet the LCD process water quality criteria of TOC<1 mg/L and conductivity<$100{\mu}S/cm$ which is stringent as compared with those of conventional reuse water quality criteria. The RO process operated at 85% recovery with stepwise increasing of permeate fluxes from 12.5 LMH to 22.0 LMH was able to meet LCD process water quality criteria. However, the transmembrane pressure increased and the period of CIP decreased as increasing permeability fluxes due to fouling of RO membrane. The optimum operational conditions of RO membrane process were permeate fluxes of 16.5~18.5 LMH with operating pressure of $6.7{\sim}12.4kgf/cm^2$ and CIP period of 20~25 days at constant 85% recovery.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.1
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• pp.1-10
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• 2016

The objective of this study was to investigate the effects of farming methods on mass balance from paddy rice. The experiment fields were established at Chunpo-myeon, Iksan-si in the Saemangeum watershed. Experiment was performed during the growing season to assess water and mass balances of the study field in 2013. The three different farming practices were applied: conventional (TR-A), drainage outlet heighten (TR-B) and slow release fertilizer use (TR-C). Drainage amount from TR-B was reduced by 28.5 % compared to the TR-A, while the amount from TR-C was similar to that of TR-A. Overall, nutrient concentration of paddy water were similar among the treatments except for T-P. Mean T-P concentration from TR-C was lower than that from TR-A (p-value<0.05). As the results of mass balance, TR-B appeared to reduce nutrient surface loss, substantially by 30.9 % and 40.8 % for T-N and T-P an compared to TR-A. TR-C treatment also demonstrated nutrient load reduction by 38.2 % and 40.1 % for T-N and T-P. The study results showed that water and fertilizer treatments are effective in surface load reduction respectively from paddy fields, and, long-term monitoring and evaluation is needed to confirm the reduction.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.1-8
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• 2002

The experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform as a general indicator organism based on chlorine, chlorine dioxide and ozone as disinfectants. The water sam-ples were taken from the outlet of settling basin in a conventional surface water treatment system that is provided with the raw water drawn from the mid-stream of the Han River. The inactivation of total coliform was experimentally ana-lyzed for the dose of disinfectant contact time, pH, Temperature and DOC. The nearly 2.4,3.0,3.9 log inactivation of total coliform killed by injecting 1 mか1 at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%(3 log), Disinfectants required were 1.70, 1.00 and 0.60 mか1 for chlorine, chlorine dioxide and ozone, respec-tively. The higher the pH is, the poorer the disinfections effects are in the range of pH 6-9 by using chlorine and ozone. But the irfluence of pH value on killing effects of chlorine dioxide is weak. The parameters estimated by the models of Chick-Watson, Hom, and Selleck from our experimental data obtained for chlorine are: log(N/ $N_{0}$ )=-0.16 CT with n= 1, log(N/ $N_{0}$ )=-0.71 $C^{0.87}$T with n$\neq$1, for Chicks-Watson model, log (N/ $N_{0}$ )= -1.87 $C^{0.47}$ $T^{0.36}$ for Hom model. For chlorine dioxide are: log(N/ $N_{0}$ )= -1.53 CT with n = 1, log(N/ $N_{0}$ )= -2.29 $C^{0.94}$T with n$\neq$1,, for Chicks-Watson model, log(N/ $N_{0}$ )= -3.64 $C^{0.43}$ $T^{0.24}$ for Hom model and for ozone are: log(N/ $N_{0}$ )= -2.59 CT with n = 1, log(N/ $N_{0}$ )= -2.28 $C^{0.36}$T with n$\neq$1, for Chicks-Watson model, log(N/ $N_{0}$ )= -4.53 $C^{0.26}$ $T^{0.19}$ for Hom model.19/ for Hom model.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.237-245
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• 2009

The purpose of this study was to investigate the clinical efficacy of latex cover developed for dental handpiece on contamination of microorganisms during dental treatment and to determine whether it can be an alternative to conventional sterilization such as autoclaving. E. fecaelis was used as a experimental microorganism instead of oral flora. Experimental bowl with 2 cm of rectangular cavity was fabricated for handpiece operating instead of oral cavity. Latex covers ($Orokeeper^{(R)}$, Orobiotech Co., Korea) and several handpieces were used after sterilization by autoclave. Four experiments were performed to evaluate bacterial contamination related with (1) various parts of dental handpiece, (2) swabbing time with alcohol sponge, (3) postoperative air-water spraying time and (4) consecutive use of latex covers without autoclaving. The results show that face of handpiece uncovered with latex cover was severely contaminated than the covered area and that most bacteria were removed by swabbing face and head area of dental hand-piece and by air-water spraying more than 15 seconds nearly up to the level of sterilization. Conclusively it can be suggested that use of latex cover for handpiece during dental procedure, swabbing with alcohol sponge is air-water spraying for more than 15 seconds after use of dental handpiece should be very useful and practical for prevention of cross infection and should be an alternative method for the sterilization of dental handpiece under some difficult situations not being able to sterilize a handpiece with autoclave.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.1-6
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• 2012

Down Stream K River has high COD (4-10 mg/L) and high $NH_3$-N concentration (3.5 mg/L during winter period). Although $NH_3$-N itself is not reported harmful at this level, it must be removed to meet drinking water standard (0.5 mg/L). We constructed a pilot plant modifying the processes of conventional drinking water facilities. Prechlorination and powdered activated carbon (PAC) dechlorination was adopted prior to a flocculation tank to remove ammonia and prevent disinfection byproducts (DBPs) formation. Also, GAC processes was included after sand filter to remove residual DOC. This pilot having a capacity of 36 ton/day was operated for one year. The GAC processes were successful to remove ammonia and many organic pollutants (DOC, MBAS, UV-254 nm absorbance, etc). Influent DOC concentrations were very high as 3~6 mg/L throughout the plant operation. It was impossible to achieve 1.0 mg/L effluent DOC, indicating that bed depth (2 m) should be increased to achieve more strict DOC quality standards. When $Cl_2$ dose was well controlled ($Cl_2/NH_3$-N ratio 10~11 on a weight basis), $NH_3$-N removal was 98% and THMs was very low possibly due to low free residual chlorine and PAC dechlorination.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.448-455
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• 2016

Diffuse pollution management in Korea initiated by the Ministry of Environment (MOE) resulted to the construction of pilot facilities termed Best Management Practices (BMPs). Twelve BMPs installed for the diffuse pollution management in the Kyung-An Stream were monitored since 2006. Data on the mass loading, removal efficiency, maintenance activities, etc. were gathered and utilized to conduct the evaluation of long-term performance of BMPs. The financial data such as actual construction, design and maintenance cost were also collected to evaluate the lifecycle cost (LCC) of BMPs. In this study, most of the maintenance activity was focused in the aesthetic maintenance that resulted to the annual maintenance cost of the four BMP types was closely similar ranging from 8,483 $/yr for retention pond to 8,888 $/yr infiltration system. The highest LCC were observed in constructed wetland ($418,324) while vegetated system had the lowest LCC ($210,418). LCC of BMPs was not so high as compared with the conventional treatment facility and sewage treatment plant. On the other hand, the relationship of removal efficiency on unit cost for TSS and TN was significant. This study will be used to design the cost effective BMP for diffuse pollution management and become models for LCC analysis.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.67-81
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• 1989

This experiment was carried out to know the mothod of changing the step of moisture content schedule with time in conventional kiln drying. For the purpose of this object. we made drying model by applying the moisture diffusion model by J.FSiau(1984) to average moisture content equation by J.Crank(1956) derived it from Fick's second law. And to verify this method of drying model. 2.5cm-thick boards and 5.0cm-thick dimension lumbers of Pinus densiflora were kiln-dried with the schedule of T11-C3 and T10-C4, respectively. And then the drying rates were investigated and compared with those calculated from drying model. The results obtained were as follows 1. Average drying rate and total drying time of board to dry to 6.5% moisture content were 0.64%/hr and 109hr., and those of dimension lumber to dry to 8.3% moisture content were 0.4%/hr. and 162hr., respectively. 2. The moisture content of shell and core decreased by equalizing treatment and increased by conditioning treatment both on board and dimension lumber. But the moisture gradient was lower after conditioning than after equalizing. 3. As the drying was proceeded, the transverse bound water diffusion coefficient all but linearly decreased, the water vapor diffusion coefficient abruptly curvilinearly increased, while the transverse diffusion coefficient curvilinearly decreased both on board and dimension lumber. But each of diffusion coefficients on board was larger than that on dimension lumber. 4. Compared to experimential drying rate of board. theoretical drying rate was larger at 30.0%-21.8% moisture content range and was similiar at 21.8%-5.4% moisture content. And in case of dimension lumber, the drying rate was similiar at 30.0%-16.1% moisture content range but theoretical drying rate was much lower at 16.1%-8.3% moisture content range. 5. The possibility of adapting this drying model to changing the moisture content schedule step with time was in the range of 21.8%-5.4% moisture content on board. And in the case of dimension lumber that was in the range of 30.0%-16.1% moisture content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.573-581
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• 1987

The fish meat paste products are rapidly growing in its production. However, the recent prohibition of AF-2 gives a lot of difficulties in the marketing of fish meat paste products manufactured ty the conventional procedures. The present study aims to obtain the optimal conditions for retaining tile quality of the fish meat paste products with long shelf-life on the market. The fried fish meat paste was sealed in the retort pouches and sterilized under the conditions which the Fo value designated to 6. The effects of the sterilization temperature and the diameter of the products on the quality factors such as jelly strength, water holding capacity, texture and in vitro protein digestibility were investigated. The jelly strength and hardness increased as the sterilization temperature increased. On the other hand, there were no differences found in water holding capacity and elasticity. Of the samples, product with diameter of 12mm showed the highest values of jelly strength, hardness, L values and in vitro protein digestibility which sterilized at $124^{\circ}C$. However. tile results of the organoleptic tests showed rather score in the products with diameter of 16 mm than 12 mm which were sterilized at $124^{\circ}C $. From the results described above, it was concluded that the fried fish meat paste products with 16 mm or less in a diameter which were sterilized at higher temperature could keep high quality.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.189-196
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• 2012

Purpose: The sufficiency of skin dose and the reemergence of patient set-up position to the success of skin cancer radiation treatment is a very important element. But the conventional methods to increase the skin dose were used to vacuum cushion, bolus and water tank have several weak points. For this reason, we producted Foxtail Millet Vacuum Cushion and evaluated the efficiency of the Foxtail Millet Vacuum Cushion in skin cancer Radiation treatment. Materials and Methods: We measured absolute dose for 3 materials (Foxtail Millet Vacuum Cushion, bolus and solid water phantom) and compared each dose distribution. We irradiated 6 MV 100 MU photon radiation to every material of 1 cm, 2 cm, 3 cm thickness at three times. We measured absolute dose and compared dose distribution. Finally we inspected the CT simulation and radiation therapy planing using the Foxtail Millet Vacuum Cushion. Results: Absolute dose of Foxtail Millet Vacuum Cushion was similar to absolute dose of bolus and solid water phantom's result in each thickness. it Showed only the difference of 0.1~0.2% between each material. Also the same result in dose distribution comparison. About 97% of the dose distribution was within the margin of error in the prescribed ranges ($100{\pm}3%$), and achieved the enough skin dose (Gross Tumor Volume dose : $100{\pm}5%$) in radiation therapy planing. Conclusion: We evaluated important fact that Foxtail Millet Vacuum Cushion is no shortage of time to replace the soft tissue equivalent material and normal vacuum cushion at the low energy radiation transmittance. Foxtail Millet Vacuum Cushion can simultaneously achieve the enough skin dose in radiation therapy planing with maintaining normal vacuum cushion' function. Therefore as above We think that Foxtail Millet Vacuum Cushion is very useful in skin cancer radiation treatment.