• Food Science and Preservation
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• v.22 no.6
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• pp.838-844
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• 2015

The purpose of this study was to perform a functional components analysis and investigate the physical properties of powders made from the stems or fruit of freeze-dried Cheonnyuncho cactus (Opuntia humifusa). The functional components analysis showed that the stem and fruit powders han vitamin C levels of 42.14 mg and 105.21 mg, respectively. The stems powder contained more lutein than the fruit powder. The fruit powder contained more vitamin C than the stem powder. The SDF (soluble dietary fiber) and IDF (insoluble dietary fiber) in the stem powder were 45.24% and 22.15%, respectively, which were higher then the values for the fruit powder. The stem and fruit powders contained 19.30 mg/g and 25.10 mg/g of crude saponin, respectively. The pH of the stem and fruit powders was 5.34 and 5.07, respectively, both indicating low acidity. The L, a and b values of the stem powder color were 78.28, -3.71, and 19.19, respectively. The L, a and b values of the fruit powder color were 55.56, 24.84, and -3.18, respectively. The stems powder had a higher bulk density, water holding capacity, and swelling power than those of the fruit powder, but water-retaining capacity of the stem powder was lower than that of the fruit powder. In addition, the stems powder had a higher viscous material content and water uptake compared to the fruit powder. Based on the above results, we determined that Cheonnyuncho (Opuntia humifusa) powder had potentially useful functional components and physical properties.

• Journal of the Korean Magnetics Society
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• v.25 no.3
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• pp.67-73
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• 2015

This is a basic research for improving soft magnetic property of Fe based nano crystalline alloy powder core. The main study is done around characteristics of permeability, core loss, and DC bias depending on amount of insulation coating agent and particle size. First, $Fe_{73.5}Si_{13.5}B_9Nb_3Cu_1$ amorphous alloy ribbon was fabricated by using the planar flow casting (PFC) device. Then, heat treatment and ball milling were done to obtain alloy powder. The amount of polyether imide (PEI) added to it was varied by 0.5, 1.0, 2.0, 2.5 wt% to have compression molding into $16ton/cm^2$. After going through crystalline heat treatment, the made toroidal nano crystalline powder core ($OD12.7mm^*ID7.62mm^*H4.75mm$) had smaller permeability as amount of insulation coating agent decreases. However, it was found out that core loss and DC bias characteristics have been improved. The reason for this results were expected to be because green density of power core decreases as amorphous alloy powder particles become smaller as amount of alloy powder insulation coating agent increases, it was determined that 1 wt% of insulation coating agent is appropriate. Also, for powder core made based on alloy powder size with amount of insulation coating agent fixed at 1 wt%, effective permeability and core loss were outstanding as particle size became bigger. However, characteristics of DC bias became worse as applied DC field increases. This is expected to be due to insulation effect, residual pores, or molding density of powder core resulting from thickness of coating on surface of alloy powder.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.216-222
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• 2015

Facilities processing raw materials containing naturally occurring radioactive materials (NORM) may give rise to enhanced radiation dose to workers due to chronic inhalation of airborne particulates. Internal radiation dose due to particulate inhalation varies depending on particulate properties, including size, shape, density, and absorption type. The objective of the present study was to assess inhalation dose sensitivity to physicochemical properties of airborne particulates. Committed effective doses to workers resulting from inhalation of airborne particulates were calculated based on International Commission on Radiological Protection 66 human respiratory tract model. Inhalation dose generally increased with decreasing particulate size. Committed effective doses due to inhalation of $0.01{\mu}m$ sized particulates were higher than doses due to $100{\mu}m$ sized particulates by factors of about 100 and 50 for $^{238}U$ and $^{230}Th$, respectively. Inhalation dose increased with decreasing shape factor. Shape factors of 1 and 2 resulted in dose difference by about 18 %. Inhalation dose increased with particulate mass density. Particulate mass densities of $11g{\cdot}cm^{-3}$ and $0.7g{\cdot}cm^{-3}$ resulted in dose difference by about 60 %. For $^{238}U$, inhalation doses were higher for absorption type of S, M, and F in that sequence. Committed effective dose for absorption type S of $^{238}U$ was about 9 times higher than dose for absorption F. For $^{230}Th$, inhalation doses were higher for absorption type of F, M, and S in that sequence. Committed effective dose for absorption type F of $^{230}Th$ was about 16 times higher than dose for absorption S. Consequently, use of default values for particulate properties without consideration of site specific physiochemical properties may potentially skew radiation dose estimates to unrealistic values up to 1-2 orders of magnitude. For this reason, it is highly recommended to consider site specific working materials and conditions and use the site specific particulate properties to accurately access radiation dose to workers at NORM processing facilities.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.232-239
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• 2009

Statements of the problem: Many denture wearers occasionally use denture adhesives to improve denture retention, stability and chewing efficiency. An ideal denture adhesive is nontoxic, non-irritating, and provides comfort to the oral mucosa. Purpose: The purpose of this study was to evaluate the cytotoxicity and adhesive properties of a selected denture adhesive. Material and methods: To test cytotoxicity of the selected denture adhesive, mouse fibroblast cells were used in MTT testing. Cytotoxicity was examined according to the concentration of the denture adhesive and incubated for 1 to 4 days. To examine adhesive property, a denture base was fabricated on an edentulous dentiform. The adhesive was applied to the denture base, then tensile bond strength was measured, to evaluate the change in retention during 3 days. Results and Conclusion: 1. 1% and 2% concentration denture adhesive cream had no cytotoxicity. 2. The tensile bond strength of the group with both denture adhesive and artificial saliva was significantly higher than that of the group with only denture adhesive(P<.05). The tensile bond strength of the group with denture adhesive was significantly higher than that of with only artificial saliva(P<.05). 3. The tensile bond strength had no significant change during 1 hour, and then gradually decreased. After 1 day, it decrease to half. Within the limitation of this study, the tested denture adhesive had no cytotoxicilty and was effective in improving denture retention. The adhesive strength began to continuously decrease after 1 hour and it decreased to half at 1 day after application.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.325-335
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• 2008

The junction between resilient denture liner and the denture base is difficult to finish and polish due to difference of the physical property of the materials. Gaps tend to be formed during finishing and polishing procedures. The purpose of this study was measuring the width of junctional gap between $Molloplast-B^{(R)}$ and denture base material after finishing and polishing procedure, and evaluating the effect of method and direction on gap width. $Molloplast-B^{(R)}$ was processed (according to the manufacturer's instruction) against Lucitone $199^{(R)}$ acrylic resin. 50 specimens were fabricated with a raised center section. All of specimens were examined and photographed with a stereoscopic microscope(x120), and the largest gap along the junction of $Molloplast-B^{(R)}$ and acrylic resin on each specimen was measured. One-way analysis of variance(ANOVA) and independent t-test at 95% confidence level were used to analyze the data and to compare groups. The results of this study were as follows. In comparison with finishing tools, the gap width was the largest in $Molloplast^{(R)}$-Cutter and the smallest in FSQ-cross cut bur. There was statistically significant difference between FSQ-cross cut bur and $Molloplast^{(R)}$-Cutter(p<0.05). There was no significant difference in gap width between the direction of polishing. The mean value of gap width was the smallest in case of no polishing, and the largest in case of polishing with pumice & tin oxide. There was statistically significant difference between pumice and pumice & tin oxide. From the results, it is concluded that the use of $Molloplast^{(R)}$-Cutter in clinic need serious consideration even though it has good cutting ability. Further careful study is needed for finishing and polishing methods for decreasing gap width in junction of two materials.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.1-10
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• 2014

Essential oils of various plants have been known for potential biological effects such as antibacterial, antifungal, spasmolytic, antiplasmodial activities and insect-repellent property. Recently, the essential oils have attracted considerable interest in oral disease therapy. This essential oil has been known as being effective on easing sick house syndrome, giving forest aroma therapy effect and acting as repellent against pest. The essential oil of Pinus koraiensi, a native plant from Hongcheon-gun, Gangwon-do, was obtained by hydrodistillation. In light of its medicinal importance, in this study its composition, antibacterial activity and the reducing effect of offensive odor have been analyzed. The composition of essential oil was determined by GC and GC-MS. We have identified 14 compounds, of which 1R-${\alpha}$-pinene (19.38 %), 3-carene (10.21 %), camphene (9.82 %), limonene (9.00 %), bicyclo[2,2,1] heptan-2-ol (8.76 %) and ${\beta}$-phellandrene (7.98 %) were the main components. Essential oils from P. koraiensis, Chamaecyparis obtusa, Abies holophylla and Pinus densiflora were compared in terms of alleviating effect of malodors caused from formaldehyde, ammonia, trimethylamine and methylmercaptan. P. koraiensis essential oil was found to decrease the amounts of ammonia and trimethylamine by 75.17 % and 77.36 %, respectively. Antibacterial activity against Streptococcus mutans and Streptococcus sobrinus, which were known as oral cavity inducer, was investigated using the paper disc agar diffusion method. The inhibition zone was observed against S. mutans (5.97 mm) and S. sobrinus (1.40 mm), respectively. P. koraiensis essential oil shown effective deodorization and inhibitory activity against oral cavity in this study might be potential material in oral sanitary industry.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.63-73
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• 2009

Recently, the use of lightweight panels in building structures has been increasing. Of the various lightweight panel types, styrofoam sandwich panels are inexpensive and are excellent in terms of their insulation capacity and their constructability. However, sandwich panels that include organic material are quite vulnerable to fire, and thus can numerous casualties in the event of a fire due to the lack of time to vacate and their emission of poisonous gas. On the other hand, lightweight foamed concrete is excellent, both in terms of its insulation ability and its fire resistance, due to its Inner pores. The properties of lightweight concrete is influenced by foaming agent type. Accordingly, this study investigates the insulation properties by foaming agent type, to evaluate the possibility of using light-weight foamed concrete instead of styrene foam. Our research found thatnon-heating zone temperature of lightweight foamed concrete using AP (Aluminum Powder) and FP (animal protein foaming agent) are lower than that of light-weight foamed concrete using AES (alkyl ether lactic acid ester). Lightweight foamed concrete using AES and FP satisfied fire performance requirements of two hours at a foam ratio 50, 100. Lightweight foamed concrete using AP satisfied fire performance requirements of two hours at AP ratio 0.1, 0.15. The insulation properties were better in closed pore foamed concrete by made AP, FP than with open pore foamed concrete made using AES.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.341-348
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• 2010

The basic principle of fry drying process of sludge lies in the rapid pressure change of sludge material caused by the change of temperature between oil and moisture due to the difference of specific heat. Therefore, the rapid increase of pressure in drying sludge induces the efficient moisture escape through sludge pores toward heating oil media. The object of this study is to carry out a systematic investigation of the influence of various parameters associated with the sludge fry drying processes on the drying efficiency. To this end, a series of parametric experimental investigation has been made together with the numerical calculation in order to obtain typical drying curves as function of important parameters such as drying temperature, sludge diameter, oil type and sludge type. In the aspect of frying temperature, especially it is found that the operation higher than $140^{\circ}C$ was favorable in drying efficiency regardless of type of waste oil employed in this study. The same result was also noted consistently in the investigation of numerical calculation, that is, in that the sludge particle drying was efficiently made over $140^{\circ}C$ irrespective of the change of particle diameter. As expected, in general, the decrease of diameter in sludge was found efficient both experiment and numerical calculation in drying due to the increased surface area per unit volume. In the investigation of oil type and property, the effect of the viscosity of waste oil was found to be more influential in drying performance. In particular, when the oil with high viscosity, a visible time delay was noticed in moisture evaporation especially in the early stage of drying. However, the effect of high viscosity decreased significantly over the temperature of $140^{\circ}C$. There was no visible difference observed in the study of sludge type but the sewage sludge with a slightly better efficiency. The numerical study is considered to be a quite useful tool to assist in experiment with more detailed empirical modeling as further work.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.548-556
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• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.