• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.837-845
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• 2017

A recirculating integrated system composed of a fluidized biofilter filled with waste-tire crumb media fixed with return sludge from wastewater treatment facility of D dyeing industrial center, and a UV/photocatalytic reactor packed with calcined $TiO_2$ coated-glass beads as photocatalyst-support, was constructed and was run to treat authentic textile-dyeing wastewater from D-dyeing industrial center, which was mixed with an alkaline polyester-weight-reducing wastewater and a wastewater from sizing process. As a result, its total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were ca. 81% and 55%, respectively. The synergy effect of the recirculating integrated system to enhance total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were evaluated at most ca. 7% and 3%, respectively. The fluidized biofilter and the UV/photocatalytic reactor were responsible for ca. 94% and 6% of the total $COD_{cr}$ removal efficiency, respectively, and were also responsible for ca. 86% and 14% of the total color-removal efficiency, respectively. Thus, the degree of the UV/photocatalytic reactor-unit process's contribution to RE(tot) of color, was about 2.4 times of that to RE(tot) of $COD_{cr}$. Therefore, the UV/photocatalytic reactor facilitated the more effective elimination of colors by breaking down the chemical bonds oriented from colors of dyes such as azo-bond, than $COD_{cr}$. In addition, the effect of the removal efficiency of each unit process(i.e., the fluidized biofilter or the UV/photocatalytic reactor) of the recirculating integrated system on RE(tot) of $COD_{cr}$ and colors, was analysed by establishing its model equation with an analytic correlation.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.68-78
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• 2020

According to the new climate change agreement, technology development to reduce greenhouse gases is actively conducted worldwide, and research on energy efficiency improvement in the field of power generation and transmission and distribution is underway [1,2]. Economic analysis of the operation method of storing and supplying surplus electricity using energy storage devices, and using energy storage devices as a frequency adjustment reserve power in regional cogeneration plants has been reported as the most profitable operation method [3-7]. Therefore, this study conducted an economic analysis for the installation of energy storage devices in the combined heat and power plant in the Czech Republic. The most important factor in evaluating the economics of battery energy storage devices is the lifespan, and the warranty life is generally 10 to 15 years, based on charging and discharging once a day. For the simulation, the ratio of battery and PCS was designed as 1: 1 and 1: 2. In general, the primary frequency control is designed as 1: 4, but considering the characteristics of the cogeneration plant, it is set at a ratio of up to 1: 2, and the capacity is simulated at 1MW to 10MW and 2MWh to 20MWh according to each ratio. Therefore, life was evaluated based on the number of cycles per year. In the case of installing a battery energy storage system in a combined heat and power plant in the Czech Republic, the payback period of 3MW / 3MWh is more favorable than 5MW / 5MWh, considering the local infrastructure and power market. It is estimated to be about 3 years or 5 years from the simple payback period considering the estimated purchase price without subsidies. If you lower the purchase price by 50%, the purchase cost is an important part of the cost for the entire lifetime, so the payback period is about half as short. It can be, but it is impossible to secure profitability through the economy at the scale of 3MWh and 5MWh. If the price of the electricity market falls by 50%, the payback period will be three years longer in P1 mode and two years longer in P2 and P3 modes.

• Progress in Medical Physics
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• v.12 no.2
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• pp.113-124
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• 2001

For veterinary imaging diagnosis, we obtained MR images of the canine brain, spine, kidney and pelvis from 3T MRI system which was equipped with the world first 3T active shield magnet. Spin echo (SE) and fast Spin Echo (FSE) images were obtained from the canine brain, spine, kidney and pelvis of normal and sick dogs using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. In addition, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix=512$\times$512, field of view (FOV)=20cm, slice thickness=3 w, number of excitations (NEX)=1. For T1-weighted MR images, we used TR=500 ms, TE=10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE=108 ms. Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.57 system. The high resolution images acquired in this study represent more than a 4-fold increase in in-plane resolution relative to conventional images obtained with a 20 cm field of view and a 5 mm slice thickness. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods. Moreover, MRI technique could begin to apply for veterinary medicine in Korea.

• Clean Technology
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• v.26 no.2
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• pp.102-108
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• 2020

In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH₃/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg^-1/2 m^-1/2 S^-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg^-1/2 m^-1/2 S^-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.

• Land and Housing Review
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• v.4 no.1
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• pp.77-87
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• 2013

About 1,800 villages have released from Greenbelt since Greenbelt-reform-policy for readjustment of the area was promoted after 1997. Even though the government intended to attract planned development & improvement of these lifted villages through District Unit Plan and designating the lifted area as low-rise and low-density zoning considering the characteristics of the Greenbelt region, there are still many problems to be solved: a lack of funds, insufficient capability for self-improvement and unexecuted SOCs in long-term etc. It seems that these problems are caused by focusing on the lifting areas itself instead of researching deeply the condition and characteristics of the villages and searching proper direction/plans of improvement before lifting Greenbelt In addition, the existing plan of village improvement and management was not considering physical and spacial characteristics of the areas, social and economic situation of residents and relationship between the villages and surrounding cities, though these conditions are different among each villages, and the related regulations are applied uniformly across all the villages and those have been causing many civil appeals and environmental problems. In these respects, this study aims to consider the problems of the lifted villages using the existing researches on them and to make typology by characteristics-data of the villages and to establish improvement strategies of each types. In this study, the villages were classified into 5 types as a result of cluster analysis on 424 villages among all 1,800 through variables of locational potentiality : location, accessibility, size and form of village, condition of regulations etc. According to function of the villages, they were divided into 4 types: urban-type, rural-type, industrial-type and neighborhood-centered-type. This study also drew 4 improvement-strategy-types by combination of locational potentiality and village-function : type of improving life-environment, type of improving production-infra, type of inducing-planned-improvement and type of constructing center-of living-circle. Finally, this study suggested the directions of the each 4 types to desirable improvement and management which could be used to make and complement plans for village improvement.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.127-136
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• 2015

To evaluate the effects of limestone powder and silica fume on the properties of high-strength high-volume ground granulated blast-furnace slag (GGBFS) blended cement concrete, this study investigated the rheology, strength development, hydration and pozzolanic reaction characteristics, porosity and pore size distribution of high-strength mortars with the water-to-binder ratio of 20, 50 to 80% GGBFS, up to 20% limestone powder, and up to 10% silica fume. According to test results, compared with the Portland cement mixture, the high-volume GGBFS mixture had much higher flow due to the low surface friction of GGBFS particles and higher strength in the early age due to the accelerated cement hydration by increase of free water; however, because of too low water-to-binder ratio and cement content, and lack of calcium hydroxide content, the pozzolanic reactio cannot be activated and the long-term strength development was limited. Limestone powder did not affect the flowability, and also accelerate the early cement hydration. However, because its effect on the acceleration of cement hydration is not greater than that of GGBFS, and it does not have hydraulic reactivity unlikely to GGBFS, compressive strength was reduced proportional to the replacement ratio of limestone powder. Also, silica fume and very fine GGBFS lowered flow and strength by absorbing more free water required for cement hydration. Capillary porosities of GGBFS blended mortars were smaller than that of OPC mortar, but the effect of limestone powder on porosity was not noticeable, and silica fume increased porosity due to low degree of hydration. Nevertheless, it is confirmed that the addition of GGBFS and silica fume increases fine pores.

• Journal of agricultural medicine and community health
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• v.40 no.3
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• pp.115-125
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• 2015

Objectives: Colorectal cancer is one of the major cancers in South Korea. We described the time trends in colorectal cancer incidence in Daejeon, a metropolitan city, and Chungcheongnam-do (Chungnam), a rural province, South Korea. Methods: Using the databases from the Daejeon Cancer Registry (DCR) and the Chungnam Cancer Registry (CCR), age-standardized (to world standard population) rates for incidence (ASRW) were calculated. Average annual percent change (AAPC) was assessed as a trend indicator. The completeness (such as the mortality/incidence ratio) and validity (such as the death certificate only %, microscopic verification %, primary site uncertain %, and age unknown %) were analyzed to examine the data quality of DCR and CCR. Results: Incidence of colorectal cancer showed increasing trend in both sexes. Over the years 2000-2012 in Daejeon, ASRW was increased significantly from 37.2 to 51.7 per 100,000 person-years (AAPC, 3.9%) among men and from 17.1 to 28.4 (AAPC, 3.9%) among women, respectively. In Chungnam, ASRW was also increased from 29.8 to 50.1 per 100,000 person-years (AAPC, 5.1%) among men and from 15.9 to 26.6 (AAPC, 3.2%) among women, respectively. The AAPC for colon cancer was greater than rectal cancer in both Daejeon and Chungnam. The trend of rectal cancer incidence was differ by sex (AAPC in men vs women, 2.7% vs 1.7% in Daejeon; 3.5% vs 0.8% in Chungnam). Indices of completeness and validity showed that the quality control of DCR and CCR was adequate to describe the trends of ASRW. Conclusions: Both Daejeon and Chungnam have had a rapid increase in colorectal cancer incidence. Monitoring and intervention are required on the risk factors which may contribute to this trend.

• Journal of agricultural medicine and community health
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• v.37 no.4
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• pp.233-245
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• 2012

Objectives: Understanding the predictor of immunization status in childhood is critical issue to improve National Immunization Program (NIP). The aims of this study were to verify the status of up-to-date or complete immunization coverage and to investigate its related factors. Methods: As of 2005, according to local residence registry data, there were 2,188 children who aged 12 to 35 months in Nonsan city, Korea. We conducted household survey for aged 12 to 35 months children, using questionnaires to obtain data on the status of immunization such as BCG, DTaP (diphtheria, tetanus, and pertussis), Polio, and MMR (mump, measles, rubella). Finally 1,472 participated in the survey. The operating definitions used in this study were following; "Complete immunization rate" refers to the rate of children who received all immunization within recommended age intervals fully "on-time"; "The 4:3:1 series" means status of receiving the fourth diphtheria-tetanus-pertussis (4 DTP), the third Polio (3 Polio), and the first measles-mumps-rubella (1 MMR) doses. Multivariate logistic regression analyses were used to determine factors affecting complete vaccination coverage of children. Results: Immunization rates of vaccine based on the vaccination card were from 92.7% to 96.4% except 4th DTaP (79.3%). Complete immunization rate of Korea NIP was 74.0% and that of the 4:3:1 series was 77.1%. A parent as primary caregiver (OR 0.59, 95% CI 0.39-0.87 at 19-35 months of children's age) and first-born children (OR 1.79, 95% CI 1.05-3.03 at 24-35 months of children's age) were significantly related to complete immunization coverage of Korea NIP. And a parent as primary care giver (OR 0.58, 95% CI 0.38-0.88 at 19-35 months of children's age) and first-born children (OR 1.94, 95% CI 1.21-3.14 at 19-35 months, OR 2.23, 95% CI 1.27-3.91 at 24-35 months of children's age) were significantly related to complete immunization rate of 4:3:1 series. Conclusions: Government should take actions to increase complete immunization rate. In particular, intervention on the secondary caregiver and non-first-born children should be needed.

• Journal of agricultural medicine and community health
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• v.38 no.1
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• pp.14-24
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• 2013

Objectives: Pregnant women in rural areas do not have access to sufficient obstetric services in their own communities due to the shortage of obstetricians. Therefore, most of these women must seek obstetrician outside of their communities. The purpose of this study was to investigate the relationship between obstetric complications and accessibility to local obstetric care in Korea. Methods: This study was an ecological study in which the unit of analysis was an administrative district. Using Korea National Health Insurance Corporation data, the total number of deliveries and the delivery proportion within and outside of the community from 2001 to 2008 were calculated for 232 administrative districts nationwide. Three outflow levels were categorized based on each district's out-of-community delivery proportion: high outflow (upper one third), moderate outflow (middle one third), and low outflow (lower one third). In addition, three obstetric complication rates (the rate of complications following abortion, ectopic and molar pregnancy, the abortion rate, and the eclampsia rate) were calculated for the 232 districts. One-way ANOVA and multivariate linear regression were used to evaluate obstetric complications among the three outflow levels. Results: The high outflow districts had higher rates of eclampsia and complications following abortion, ectopic, and molar pregnancy compared to the other districts (ANOVA, p<0.05). However, there was no significant difference in the abortion rate among the three groups. Multiple linear regression analysis showed that high outflow districts were statistically significant in the rate of complications following abortion, ectopic and molar pregnancy and eclampsia rate after adjusting for local tax per capita (p<0.01). Conclusion: These results indicate that poor access to local obstetric care correlate with poor obstetric outcomes (delayed or excessive bleeding, embolism, genital tract or pelvic infection, shock or other complications following abortion and ectopic or molar pregnancy, or eclampsia).