• Journal of Korean Society of Water and Wastewater
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• v.31 no.3
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• pp.229-236
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• 2017

In this study, a direct contact membrane module was manufactured to be used in a pilot scale membrane distillation process to treat $3m^3/day$ of the digestate produced from anaerobic digestion of livestock manure. In order to investigate the performance of the membrane module, permeate flux was measured with and without spacer inside the module under various condition of temperature difference and cross flow velocity (CFV) through the membrane surfaces. Flux recovery rate after chemical cleaning was also investigated by applying three different cleaning methods. Additionally, thermal energy consumption was theoretically simulated based on actual pilot plant operation conditions. As results, we observed flux of the module with spacer was almost similar to the theoretically predicted value because the installation of spacer reduced the channeling effect inside the module. Under the same operating condition, the permeate flux also increased with increasing temperature difference and CFV. As a result of chemical in-line cleaning using NaOCl and citric acid for the fouled membranes, the recovery rate was 83.7% compared to the initial flux when NaOCl was used alone, and 87% recovery rate was observed when only citric acid was used. However, in the case of using only citric acid, the permeate flux was decreased at a rapid rate. It seemed that a cleaning by NaOCl was more effective to recover the flux of membrane contaminated by the organic matter as compared to a cleaning by citric acid. The total heat energy consumption increased with increasing CFV and temperature difference across the membrane. Thus, further studies should be intensively conducted to obtain a high permeate flux while keeping the energy consumption to a minimum for a practical application of membrane distillation process to treat wastewater.

• Korean Journal of Remote Sensing
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• v.17 no.1
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• pp.99-109
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• 2001

In order to establish effective fishing ground environment equipment and artificial reef in coastal area, the methodology to select the most suitable area for artificial reef should be applied after analyzing the correlation between fishing ground environment and ocean environment. In this paper, thematic maps were prepared by using satellite remote sensing and GIS for the sea surface temperature, chlorophyll, transparency, the depth of sea water and the condition of submarine geologic which are considered as the most elements when selecting suitable area for artificial reef in Tong-Yong bay. Then, the most suitable area for artificial reef was selected by giving weight score depending on the suitable condition of this area and analyzing spatial data. The results showed it makes possible for this methodology, which selects the suitable area for artificial reef using satellite remote sensing and GIS, to manage the institution of artificial reef more entirely and efficiently through analyzing and visualizing.

• Journal of Korea Water Resources Association
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• v.52 no.7
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• pp.483-492
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• 2019

An analytical model was developed to estimate the stream depletion due to cyclic groundwater pumping by extending the Hunt's analytical solution which was derived from considering the hydraulic characteristics of the aquifer and the streambed. The model was applied to analyze the long-term effects of groundwater pumping on stream depletion during irrigation season. For the case of a total of 1,500 conditions according to various aquifer and streambed hydraulic characteristics and stream-well distance, the stream depletion due to cyclic groundwater pumping for 10 years was calculated and the results were graphically represented. Especially, the maximum and average stream depletion rates were calculated and compared with the results for continuous groundwater pumping. Furthermore, considering both stream depletion and return flow rates, the limit hydraulic condition that minimizes the influence of groundwater pumping for irrigation water supply on stream depletion was suggested.

• Animal Bioscience
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• v.34 no.7
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• pp.1235-1242
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• 2021

Objective: The purpose of this study was to identify through infrared thermal imaging technology the facial surface temperature (FST) of laying hens in response to the variations in their thermal environment, and to identify the regional differences in FST to determine the most stable and reliable facial regions for monitoring of thermoregulatory status in chickens. Methods: Thirty Hy-Line Brown hens (25-week-old) were sequentially exposed to three different thermal conditions; optimal (OT, 22℃±2℃), low (LT, 10℃±4℃), and high temperature (HT, 30℃±2℃). The mean values of FST in five facial regions including around the eyes, earlobes, wattles, beak and nose, and comb were recorded through infrared thermography. The maximum FST (MFST) was also identified among the five face-selective regions, and its relationship with temperature-humidity index (THI) was established to identify the range of MFST in response to the variations in their thermal environment. Results: Hens exposed to OT condition at 15:00 displayed a higher temperature at wattles and around the eyes compared to other regions (p<0.001). However, under LT condition at 05:00 to 08:00, around the eyes surface temperature showed the highest value (p<0.01). In HT, wattles temperature tended to show the highest temperature over almost time intervals. Main distribution regions of MFST were wattles (63.3%) and around the eyes (16.7%) in OT, around the eyes (50%) in LT, and wattles (62.2%) and comb (18.3%) in HT. The regression equation between MFST and THI was estimated as MFST = 35.37+0.2383×THI (R² = 0.44; p<0.001). Conclusion: The FST and the frequency of MFST in each facial region of laying hens responded sensitively to the variations in the thermal environment. The findings of this experiment provide useful information about the effect of the thermal conditions on the specific facial regions, thus offering an opportunity to stress and welfare assessment in poultry research and industry.

• Journal of Audiology & Otology
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• v.24 no.2
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• pp.91-98
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• 2020

Background and Objectives: This study aimed to compare functional hearing with the use of a personal sound amplification product (PSAP) or a basic hearing aid (HA) among sensorineural hearing impaired listeners. Subjects and Methods: Nineteen participants with mild-to-moderate sensorineural hearing loss (SNHL) (26-55 dB HL; pure-tone average, 0.5-4 kHz) were prospectively included. No participants had prior experience with HAs or PSAPs. Audiograms, speech intelligibility in both quiet and noisy environments, speech quality, and preference were assessed in three different listening conditions: unaided, with the HA, and with the PSAP. Results: The use of PSAP was associated with significant improvement in pure-tone thresholds at 1, 2, and 4 kHz compared to the unaided condition (all p<0.01). In the quiet environment, speech intelligibility was significantly improved after wearing a PSAP compared to the unaided condition (p<0.001), and this improvement was better than the result obtained with the HA. The PSAP also demonstrated similar improvement in the most comfortable levels compared to those obtained with the HA (p<0.05). However, there was no significant improvement of speech intelligibility in a noisy environment when wearing the PSAP (p=0.160). There was no significant difference in the reported speech quality produced by either device or in participant preference for the PSAP or HA. Conclusions: The current result suggests that PSAPs provide considerable benefits to speech intelligibility in a quiet environment and can be a good alternative to compensate for mild-to-moderate SNHL.

• Korean Journal of Audiology
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• v.24 no.2
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• pp.91-98
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• 2020

Background and Objectives: This study aimed to compare functional hearing with the use of a personal sound amplification product (PSAP) or a basic hearing aid (HA) among sensorineural hearing impaired listeners. Subjects and Methods: Nineteen participants with mild-to-moderate sensorineural hearing loss (SNHL) (26-55 dB HL; pure-tone average, 0.5-4 kHz) were prospectively included. No participants had prior experience with HAs or PSAPs. Audiograms, speech intelligibility in both quiet and noisy environments, speech quality, and preference were assessed in three different listening conditions: unaided, with the HA, and with the PSAP. Results: The use of PSAP was associated with significant improvement in pure-tone thresholds at 1, 2, and 4 kHz compared to the unaided condition (all p<0.01). In the quiet environment, speech intelligibility was significantly improved after wearing a PSAP compared to the unaided condition (p<0.001), and this improvement was better than the result obtained with the HA. The PSAP also demonstrated similar improvement in the most comfortable levels compared to those obtained with the HA (p<0.05). However, there was no significant improvement of speech intelligibility in a noisy environment when wearing the PSAP (p=0.160). There was no significant difference in the reported speech quality produced by either device or in participant preference for the PSAP or HA. Conclusions: The current result suggests that PSAPs provide considerable benefits to speech intelligibility in a quiet environment and can be a good alternative to compensate for mild-to-moderate SNHL.

• Clean Technology
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• v.15 no.4
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• pp.253-257
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• 2009

The waste solution discharged form the LCD(Liquid Crystal Display) manufacturing process contains phosphoric acid, nitric acid, acetic acid and metal ions such Al and other impurities. In this study, vacuum evaporation and diffusion dialysis was developed to commercialize an efficient system for recovering the high-purity phosphoric acid and manufacturing monoammonium phosphate. By vacuum evaporation, almost 99% of nitric and acetic acid was removed. Also, by diffusion dialysis, about 97.5% of Al was removed. Monoammonium phosphate was manufactured from purified phosphoric acid and ammonium hydroxide. In order to get the optimum manufacturing condition, the molar ratio of ammonium hydroxide and phosphoric acid, pH and temperature was controlled. Using this optimum condition, we obtained the recovery rate of monoammonium phosphate of about 90%.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.107-120
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• 2014

First purpose of this study is to build Korean mountain ridgelines based on GIS by using spatial information and analyze natural environment around mountain ridgelines built before. Second purpose of this study is to integrate Korean ridgelines and natural environment built before and then provide the integrated information related to ridgelines for public. To do so, fist of all, Korean mountain ridgelines including Deagan, Jeongmeak, Gimeak, Jimeak, are built as spatial information. Second, Encoding of mountain ridgelines is conducted to analyze main and divaricate ridgelines systematically as grades of ridgelines. Third, based on spatial information, present condition using natural environment including geographical information, ecological zoning map, environmental conservation value assessment map, is analyzed. Finally, as a method integrating and using the aforementioned three information, the system providing integrated information based on GIS is proposed, To build the GIS data of Gimeak and Jimeak, they should be analyzed in more detail than Beakdu Deagan and Jeongmeak, so existing methodology to build mountain ridgelines based on GIS is improved. According to the distance of each mountain ridgeline, they are separated into five grades, and encoding of each mountain ridgeline based on Beakdu Deagan is applied to all mountain ridgelines to figure out the present condition of ridgelines themselves. In addition, according to the distance of each mountain ridgeline, it is separated into three areas: core, buffer, median zone. Based on three zones, the way to make use of the information efficiently related to mountain ridgelines is proposed. This study systematizes Korean mountain ridgelines which did not have systematic structures and then analyzes systematic mountain ridgelines. Based on this analysis, this study finds the way to makes use of information related to mountain ridgelines effectively.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.516-527
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• 2009

We assessed fish fauna and habitat suitability indexes in the Geum river basin. Field monitoring was conducted for ecological and habitat condition assessment at 23 sites from October 2007 to March 2009. The habitat suitability indexes established for dominant fish species using the monitoring data were employed to assess riverine health conditions such as composition ratio of fish species, richness and dominance indexes, bio-diversity(dominance index, diversity, evenness and richness), and water depth, velocity and substrate size. Twenty-one species(42%) including Rhodeus uyekii and Pseudopungtungia nigra were found endemic out of the 50 species in 11 families sampled during this study period. The most frequently found one was Zacco platypus(34.3%) followed by Z. koreanus(10.2%) and Coreoleuciscus splendidus(8.4%). For Z. platypus, the dominant fish species in the basin, the favored habitat conditions were estimated to be 0.1~0.9 m for water depth, 0~0.9m/s for flow velocity and silt(<0.1mm)~cobbles(100.0~300.0mm) for substrate size, respectively. Overall, it was concluded that the Geum river basin has been relatively well protected from the anthropogenic disturbance for the legally protected species including the endemic species studied in this study.

• Journal of Life Science
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• v.20 no.1
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• pp.77-81
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• 2010

We separated the bacteria showing protease activity from Reticulitermes speratus which is known as the only termite species in Korea. Then, we collected the best activated strain and studied the optimal culture condition for producing the enzyme. According to the results of observing morphological and physiological characteristics, and the type of 16S rRNA of the strain, it was identified as Serratia marcescens and named S. marcescens strain TM-3215. This strain showed the best activity under conditions of 0.8% (w/v) starch, 0.4% (w/v) peptone, 0.08% (w/v) $MgSO_4{\cdot}7H_2O$, $30^{\circ}C$ and pH 8.0. After being cultivated under optimal conditions for 9 hr, the strain produced 19.8 U/ml of enzyme, an amount 1.8 times greater than the control.