• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.92-101
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• 2012

The degradation of one of the commercially important hydrogel based on acrylic acid and acryl amide, (acrylic acid-co-acryl amide) hydrogels, by means of ultrasound irradiation and its combination with heterogeneous ($TiO_2$) was investigated. 24 kHz of ultrasound irradiation was provided by a sonicator, while an ultraviolet source of 16 W was used for UV irradiation. The extent of sonolytic degradation increased with increasing ultrasound power (in the range 30-80 W). $TiO_2$ sonophotocatalysis led to complete (acrylic acid-co-acryl amide) hydrogels degradation with increasing catalyst loading, while, the presence of $TiO_2$ in the dark generally had little effect on degradation. Therefore, emphasis was totally on the sonolytic and sonophotocatalytic degradation of hydrogels and a synergy effect was calculated for combined degradation procedures (Ultrasound and Ultraviolet) in the presence of $TiO_2$ nanoparticles. $TiO_2$ sonophotocatalysis was always faster than the respective individual processes due to the enhanced formation of reactive radicals as well as the possible ultrasound-induced increase of the active surface area of the catalyst. A kinetics model based on viscosity data was used for estimation of degradation rate constants at different conditions and a negative order for the dependence of the reaction rate on total molar concentration of (acrylic acid-co-acryl amide) hydrogels solution within the degradation process was suggested.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.1027-1033
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• 2009

For the assesment of pollutant loads, a monitoring has been conducted to identify hydrologic conditions and water quality of the Oenam watershed in Juam Lake, and the SWAT model integrated with GIS was applied to the watershed and evaluated for its applicability through calibration and verification using observed data. For the model application, digital maps were constructed for watershed boundary, land-use, soil series, digital elevation, and topographic input data of the Oenam watershed using Arcview. The observed runoff was 832.8 mm while the simulated runoff was 842.8 mm in 2003. The model results showed that the simulated runoff was in a good agreement with the observed data and indicated reasonable applicability of the model. In terms of nutrient load, the simulation results of T-N, T-P showed a similar trend to observed values. The observed T-N load was 10.8 kg/ha and the simulated T-N load was 7.6 kg/ha while the observed T-P load was 0.21 kg/ha and the simulated T-P load was 0.18 kg/ha. In general, SWAT model predicted observed runoff and loads of T-N and T-P after calibration with observed data in acceptable range. Overall, SWAT model was satisfactory in estimation of nutrient pollutant loads of the rural watershed.

• Korean Journal of Adult Nursing
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• v.25 no.3
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• pp.275-288
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• 2013

Purpose: The purpose of this study was to perform an economic analysis and estimate the fee for the practices that carried out by Emergency Nurse Practitioner (ENP) using relative value scale (RVS) and its conversion factor. Methods: First, we developed ENP's RVS for 25 advanced nursing services based on ENP's workload and its time spent by survey. A cost analysis was performed to evaluate the conversion factor of ENP's RVS. The share of ENP's contribution to fee-for-service in emergency setting was also analyzed. Results: Calculation of the RVS of 25 advanced nursing practices showed a range of points from 73.4 to 296.3 and an average of 145.1 points. The relevant conversion factor for advanced nursing practices among ENP was estimated at 12.2~15.9 won. The contribution rate of ENP's advanced nursing practices in the relative value scale of the national health insurance was estimated at 13.1~17.0%. Conclusion: The practices of ENP are not compensated separately and its reimbursement is usually included in physician fee. An estimation of nursing fee and an independent fee related to ENP's services shows the contribution rate to total revenue. It suggests that emergency nurse practitioners be considered as a revenue source the in emergency room.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.589-598
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• 2018

To maintain safety and reliability of reactors, redundant sensors are usually used to measure critical variables and estimate their averaged time-dependency. Nonhealthy sensors can badly influence the estimation result of the process variable. Since online condition monitoring was introduced, the online cross-calibration method has been widely used to detect any anomaly of sensor readings among the redundant group. The cross-calibration method has four main averaging techniques: simple averaging, band averaging, weighted averaging, and parity space averaging (PSA). PSA is used to weigh redundant signals based on their error bounds and their band consistency. Using the consistency weighting factor (C), PSA assigns more weight to consistent signals that have shared bands, based on how many bands they share, and gives inconsistent signals of very low weight. In this article, three approaches are introduced for improving the PSA technique: the first is to add another consistency factor, so called trend consistency (TC), to include a consideration of the preserving of any characteristic edge that reflects the behavior of equipment/component measured by the process parameter; the second approach proposes replacing the error bound/accuracy based weighting factor ($W^a$) with a weighting factor based on the Euclidean distance ($W^d$), and the third approach proposes applying $W^d$, TC, and C, all together. Cold neutron source data sets of four redundant hydrogen pressure transmitters from a research reactor were used to perform the validation and verification. Results showed that the second and third modified approaches lead to reasonable improvement of the PSA technique. All approaches implemented in this study were similar in that they have the capability to (1) identify and isolate a drifted sensor that should undergo calibration, (2) identify a faulty sensor/s due to long and continuous missing data range, and (3) identify a healthy sensor.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.3
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• pp.15-19
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• 2006

In shallow water active sonar environment, reverberation which is a non-white noise is one of the main source of performance degradation of target detection. In this case, the received signal is whitened before applying matched filter known as an optimum filter in the presence of white noise. However implementation of this method is very difficult because of the non-stationary characteristic of reverberation. Traditionally reverberation is assumed local stationary. In this paper, we estimate a range of stationary of reverberation signal, and then propose a pre-whitening method which improve the performance of pre-whitening block normalized matched filter in presence of non-white reverberation noise. Proposed whitener shows better whitening performance than traditional whitener because it use later as well as before reverberation of target signal. To evaluate performance of the proposed whitener, an actual measurement data sampled at the East-Sea is used for computer simulation. The target detector with new whitener is shown better performance than detector with traditional whitener.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.325-332
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• 2006

The dynamic responses of human standing postural control were investigated when subjects were exposed to long-term horizontal vibration. It was hypothesized that the motion of standing posture complexity mainly occurs in the mid-sagittal plane. The motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced anterior/posterior (AP) motion. The platform acceleration and the trunk angular velocity were used as the input and the output of the system, respectively. A method was proposed to identify the complexity of the standing posture dynamics. That is, during AP platform motion, the subject's knee, hip and neck were tightly constrained by fixing assembly, so the lower extremity, trunk and head of the subject's body were individually immovable. Through this method, it was assumed that the ankle joint rotation mainly contributed to maintaining their body balance. Four subjects took part in this study. During the experiment, the random vibration was generated at a magnitude of $0.44m/s^2$, and the duration of each trial was 40 seconds. Measured data were estimated by the coherence function and the frequency response function for analyzing the dynamic behavior of standing control over a frequency range from 0.2 to 3 Hz. Significant coherence values were found above 0.5 Hz. The estimation of frequency response function revealed the dominant resonance frequencies between 0.60 Hz and 0.68 Hz. On the basis of our results illustrated here, the linear model of standing postural control was further concluded.

• Environmental Analysis Health and Toxicology
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• v.23 no.4
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• pp.257-265
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• 2008

Nanotechnology is emerging as one of the key technologies of the 21 st century and is expected to enable one to broaden the applicability across a wide range of sectors that can benefit public and improve industrial competitiveness. Already, consumer products containing nanomaterials are available in markets including coatings, computers, clothing, cosmetics, sports equipment and medical devices. Recently, Institute of Occupational Medicine in UK reported an occupational hygiene review for nanoparticles in the viewpoint of nanotoxicity. They reported that the exposure control is very important issues in workplace for exposure assessment, but no proper methods are available to measure the extent of exposures to nanoparticles in the workplace. Therefore, for the estimation of exposure of nanomaterials, we have to approach the material-balance methodology, which similarly carried out in TRI (toxic release inventory) for hazardous chemicals. In order to use this methodology, the exposure source of nanomaterials should be determined firstly. Therefore, herein we investigated the main sources and processes for the exposure to nanomaterals by conducting the survey. The results could be used to define and assess nanohazard sources.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.10-17
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• 2008

The objective of this study was to estimate the pollutant loads from paddy fields by cultivation practices using a non-point-sources models. One of them is CREAMS-PADDY model that was developed considering the water balance and mass balance of paddy fields. The CREAMS-PADDY model was applied to provide basic data to reduce runoff loadings under various scenarios such as various water management control and various fertilizer condition. The model was verified against T-N, T-P and runoff flow data collected during cropping periods at 2000. The model results agreed well with the measured data in verification. The results showed that the model could be used for estimating the runoff loadings from irrigated paddy fields by cultivation practices was possible. Comparison of simulated the standard height and the sluice management of T-N and T-P runoff loadings from paddy fields were +32.4%, +10.3% in 10 mm below the standard height, -29.2%, -35.9% in 20 mm above the standard height, 52.6%, 59.0% in 40 mm above the standard height, respectively. Comparison of simulated the standard fertilizer and the fertilizer control of T-N and T-P runoff loadings from paddy fields were -1.3%, -21.7%in reduction of conventional fertilizer 30%, -1.0%, -12.5% in reduction of standard fertilizer 30%, respectively. Therefore, reducing nonpoint-sources nutrient loading by reducing fertilization may not work well in the range of normal paddy rice farming practices, and instead it could be achieved by reducing surface drainage outflow.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.490-497
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• 2007

A Combined sewer overflows (CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available (which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a continuous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban drainage system used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range $3{\times}DWF$ (dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a decision of storage volume for CSOs reduction and water quality protection.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.303-310
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• 2015

This study was conducted to estimate of carbon stock and greenhouse gas (GHGs) removals by tree species and forest type at Gangwon province. We used a point sampling data with permanent sample plots in national forest inventory and national emission factors. GHGs emissions was caclulated using the stock change method related to K-MRV and IPCC guidance. Total carbon stock and greenhouse gas removals were high in deciduous forest and species than in coniferous. The range of annual net greenhouse gas emissions in other deciduous species was from $-11,564.83Gg\;CO_2\;yr^{-1}$ to $-13,500.60Gg\;CO_2\;yr^{-1}$ during 3 years (2011~2013). On the other hand, coniferous forest was temporally converted to source due to reducing of growing stock in 2012. It was that growing stocks and forest area were likely to reduce by the deforestation and clear cutting. This study did not consider other carbon pools (soil and dead organic matter) due to the lack of data. This study needs to complement the activity data and emission factors, and then will find the way to calculate the greenhouse gas emissions and removals in the near future.