• Economic and Environmental Geology
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• v.42 no.4
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• pp.357-366
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• 2009

Since weathering weakens the rock fabric and exaggerates any structural weakness, it affects mechanical properties as well as physical and chemical properties of rock. Weathering leads to a decrease in density, strength, friction angle and cohesion, and subsequently it affects negatively on the stability of rock slope. The purpose of the study is to investigate the changes of the rock slope stability caused by discontinuities which have different weathering grades. For that, the discontinuity samples which are divided into two different weathering grades are obtained from the field and tested their mechanical properties such as JCS, JRC and residual friction angle. In order to evaluate the effects on the stability of slope due to weathering, the deterministic analysis is carried out. That is, the factors of safety for planar failure are calculated for rock masses which have two different weathering grades, such as fresh and weathered rock mass. However, since the JRC and friction angle values are widely scattered and the deterministic analysis cannot consider the variation, the factors of safety cannot represent properly the stability of the rock slope. Therefore, the probabilistic analysis has been used to consider the scattered values. In the deterministic analysis, the factors of safety for the fresh discontinuity and weathered discontinuity are 1.25 and 1.0, respectively. The results indicate the fresh discontinuities are stable for planar failure and the weathered discontinuities are marginally stable. However, the probabilities of failure for the fresh discontinuity and weathered discontinuity are 25.6% and 45.9%, respectively. This shows that both discontinuities are analyzed as unstable in the probabilistic analysis.

• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.46-52
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• 2021

In this study, the on-site location identification and response system was proposed by accurately checking the location information of rescue requesters in the buildings using the smartphone Wi-Fi AP. The location server was requested to measure the strength of the Wi-Fi AP at least 25 times at 8 different building location points. And the accuracy of the position and the error range were checked by analyzing the coordinate values of the received positions. In addition, the response time was measured by changing the conditions of location information in three groups to compare the response time for saving lives with and without location information. The minimum and maximum error values for the eight cases were found to be at least 4.137 m and up to 14.037 m, respectively, with an average error of 9.525 m. Compared to the base transceiver station (BTS) based position error value of 263m, the range could be reduced by up to 93%. When the location information was given, it took 10 minutes and 50 seconds to save lives; however, when there was no location information at all, rescue process took more than 45 minutes. From this research effort, it was analyzed that the acquisition of the location information of rescuees in the building using the smartphone Wi-Fi AP approach is effective in reducing the life-saving time for on-site responses.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.434-442
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• 2017

The UV light in sunlight breaks down the chemical bonds in a polyolefin polymer through a process called photodegradation, ultimately causing cracking, chalking, colour changes, and loss of physical properties such as impact strength, tensile strength, elongation, and others. UV absorbers are used to prevent or terminate the oxidation of plastics by UV light. They are receptive to UV radiation and dissipate the energy harmlessly as heat. Benzotriazoles and benzophenones are used mainly in polyolefins such as polyethylene and polypropylene. In this study, we have developed a method for the analysis of 12 UV absorbers, which are Uvinul 3000, Cyasorb UV 24, Uvinul 3040, Tinuvin 312 and P, Seesorb 202, Chimassorb 81, Tinuvin 329, 234, 326, 328 and 327, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The UV absorbers in food simulants were determined by reversed-phase high performance liquid chromatograph-ultraviolet detector with 310 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.049~0.370 mg/L), and limits of quantification (0.149~1.120 mg/L). The recoveries of UV absorbers spiked to four food simulants ranged from 70.05% to 110.13%. The developed method would be used as a reliable tool to determine concentrations of the migrated UV absorbers.

• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.510-519
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• 2021

The purpose of this study was to investigate the effect of the microbial reduction and quality maintenance of the physical and chemical pretreatment of Allium monanthum. For physical treatment, handwash, bubble wash and ultrasonication were conducted at 50℃ and 60℃ for 1, 3 and 5 minutes, respectively, and for chemical treatment the sample was immersed in fumaric acid and acetic acid of 1.5% and 2% concentrations for 1, 3 and 5 minutes, respectively. As a result of the microorganism and quality analysis, 3 minutes of bubble wash was the most effective physical pretreatment in reducing fungi although the effect on reducing total viable bacterial was small. Furthermore, 5 minutes of ultrasonication at 60℃ significantly reduced microorganisms, but also resulted in the reduction of the a value of chromaticity, which cause the green color to fade. With chemical pretreatment, it was found that treating with fumaric acid was more effective in reducing the total viable bacteria and fungi than acetic acid. The result shows that 1.5% concentration of fumaric acid is the most effective with 3 minutes of treatment time. The quality of Allium monanthum were compared in the combination of the two most effective microorganism reduction pretreatments: 3 minutes of bubble wash (B3) and 3 minutes in 1.5% fumaric acid (F153). As a result of analyzing the quality characteristics over 9 days of storage at 4℃ after the treatments, it was revealed that the BF treatment is more effective in reducing fungi than the total viable bacteria. The results shows that the BF treatment is more effective in reducing total viable bacteria, whereas the F153 treatment is more effective in reducing fungi. Also, it was found that the 𝚫E value in BF was the lowest, whereas F153 treatment showed the green color faded. The maximum cohesiveness changed more significantly in the green stems than in the roots. On the 9th day of storage, the hardness of the green stem was found to be maintained at the highest level (P<0.05) after F153 treatment, whereas that of the roots decreased (P<0.05) since the 6th day after the bubble wash. Considering the reduction of microorganisms and the quality maintenance of Allium monanthum, the most effective pretreatment methods were 3 minutes in 1.5% fumaric acid for reducing microorganisms and maintaining color and maximum cohesiveness, and the combined process could also be effective if the expiration period is within 3 days.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.69-74
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• 2013

This study has been performed for 150 days from February 1 - June 31, 2012 aiming at analyzing biologically hazardous factors in order to develop HACCP system for the vinegared pickle radishes. A process chart was prepared as shown on Fig. 1 by referring to manufacturing process of manufacturer of general vinegared pickle radishes regarding process of raw agricultural products of vinegared pickle radishes, used water, warehousing of additives and packing material, storage, careful selection, washing, peeling off, cutting, sorting out, stuffing (filling), internal packing, metal detection, external packing, storage and consignment (delivery). As a result of measuring Coliform group, Staphylococcus aureus, Salmonella spp., Bacillus cereus, Listeria Monocytogenes, E. coli O157:H7, Clostridium perfringens, Yeast and Mold before and after washing raw radishes, Bacillus cereus was $5.00{\times}10$ CFU/g before washing but it was not detected after washing and Yeast and Mold was $3.80{\times}10^2$ CFU/g before washing but it was reduced to 10 CFU/g after washing and other pathogenic bacteria was not detected. As a result of testing microorganism variation depending on pH (2-5) of seasoning fluid (condiment), pH 3-4 was determined as pH of seasoning fluid as all the bacteria was not detected in pH3-4. As a result of testing air-borne bacteria (number of general bacteria, colon bacillus, fungus) depending on each workplace, number of microorganism of internal packing room, seasoning fluid processing room, washing room and storage room was detected to be 10 CFU/Plate, 2 CFU/Plate, 60 CFU/Plate and 20 CFU/Plate, respectively. As a result of testing palm condition of workers, as number of general bacteria and colon bacillus was represented to be high as 346 $CFU/Cm^2$ and 23 $CFU/Cm^2$, respectively, an education and training for individual sanitation control was considered to be required. As a result of inspecting surface pollution level of manufacturing facility and devices, colon bacillus was not detected in all the specimen but general bacteria was most dominantly detected in PP Packing machine and Siuping machine (PE Bulk) as $4.2{\times}10^3CFU/Cm^2$, $2.6{\times}10^3CFU/Cm^2$, respectively. As a result of analyzing above hazardous factors, processing process of seasoning fluid where pathogenic bacteria may be prevented, reduced or removed is required to be controlled by CCP-B (Biological) and threshold level (critical control point) was set at pH 3-4. Therefore, it is considered that thorough HACCP control plan including control criteria (point) of seasoning fluid processing process, countermeasures in case of its deviation, its verification method, education/training and record control would be required.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.140-147
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• 2016

A process for manufacturing virally-safe porcine bone hydroxyapatite (HA) has been developed to serve as advanced xenograft material for dental applications. Porcine bone pieces were defatted with successive treatments of 30% hydrogen peroxide and 80% ethyl alcohol. The defatted porcine bone pieces were heat-treated in an oxygen atmosphere box furnace at $1,300^{\circ}C$ to remove collagen and organic compounds. The bone pieces were ground with a grinder and then the bone powder was sterilized by gamma irradiation. Morphological characteristics such as SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) images of the resulting porcine bone HA (THE Graft$^{(R)}$) were similar to those of a commercial bovine bone HA (Bio-Oss$^{(R)}$). In order to evaluate the efficacy of $1,300^{\circ}C$ heat treatment and gamma irradiation at a dose of 25 kGy for the inactivation of porcine viruses during the manufacture of porcine bone HA, a variety of experimental porcine viruses including transmissible gastroenteritis virus (TGEV), pseudorabies virus (PRV), porcine rotavirus (PRoV), and porcine parvovirus (PPV) were chosen. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the $1,300^{\circ}C$ heat treatment. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.81$$ for PRV, $${\geq_-}6.28$$ for PRoV, and $${\geq_-}5.21$$ for PPV. Gamma irradiation was also very effective at inactivating the viruses. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the gamma irradiation. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.87$$ for PRV, $${\geq_-}6.05$$ for PRoV, and $${\geq_-}4.89$$ for PPV. The cumulative log reduction factors achieved using the two different virus inactivation processes were $${\geq_-}9.30$$ for TGEV, $${\geq_-}11.68$$ for PRV, $${\geq_-}12.33$$ for PRoV, and $${\geq_-}10.10$$ for PPV. These results indicate that the manufacturing process for porcine bone HA from porcine-bone material has sufficient virus-reducing capacity to achieve a high margin of virus safety.

• Korean Journal of Community Nutrition
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• v.26 no.5
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• pp.327-336
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• 2021

Objectives: This study was conducted to create a 3D printable snack dish model for the elderly with low food or fluid intake along with barriers towards eating. Methods: The decision was made by the hybrid-brainstorming method for creating the 3D model. Experts were assigned based on their professional areas such as clinical nutrition, food hygiene and chemical safety for the creation process. After serial feedback processes, the grape shape was suggested as the final model. After various concept sketching and making clay models, 3D-printing technology was applied to produce a prototype. Results: 3D design modeling process was conducted by SolidWorks program. After considering Dietary reference intakes for Koreans (KDRIs) and other survey data, appropriate supplementary water serving volume was decided as 285 mL which meets 30% of Adequate intake. To consider printing output conditions, this model has six grapes in one bunch with a safety lid. The FDM printer and PLA filaments were used for food hygiene and safety. To stimulate cognitive functions and interests of eating, numbers one to six was engraved on the lid of the final 3D model. Conclusions: The newly-developed 3D model was designed to increase intakes of nutrients and water in the elderly with dementia during snack time. Since dementia patients often forget to eat, engraving numbers on the grapes was conducted to stimulate cognitive function related to the swallowing and chewing process. We suggest that investigations on the types of foods or fluids are needed in the developed 3D model snack dish for future studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.537-543
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• 2019

Alumina(Al₂O₃) is a ceramic material used in industry with a range of particle sizes and characteristics. In this study, a boehmite sol was prepared by a hydrolysis and peptizing process using the Sol-Gel method from aluminum isopropoxide (AIP). γ-Al₂O₃ was prepared by drying and calcining. To prevent particle agglomeration during the manufacturing process, four kinds of polyvinyl alcohol (PVA) with molecular weights of 9,000~10,000, 31,000~50,000, 89,000~98,000, and 130,000 were added and three concentrations of HNO₃ (0.1, 0.3, 0.5 molar ratio) were added to determine their effects on the particles. The crystal structure, composition, particle size and shape of the prepared γ-Al₂O₃ were confirmed through x-ray diffraction (XRD), x-ray fluorescence analyzer (XRF), particle size analyzer (PSA), and field emission scanning electron microscopy (FE-SEM). As a result, γ-Al₂O₃ with a purity of approximately 98.2% was synthesized, and the particle size decreased and the uniformity increased with increasing ratio of HNO₃ addition and PVA molecular weight. From these results, the particle size can be controlled during the manufacturing process of γ-Al₂O₃ by controlling the addition ratio of PVA and HNO₃.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.62-68
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• 2016

The feeder cable assembly is an automotive part used for telecommunication. If it malfunctions, the control and safety of the automobile can be put at risk. ALT (Accelerated Life Testing) is a testing process for products in which they are subjected to conditions (stress, strain, temperatures, etc.) in excess of their normal service parameters in an attempt to uncover faults and potential modes of failure in a short amount of time. Failure is caused by defects in the design, process, quality, or application of the part, and these defects are the underlying causes of failure or which initiate a process leading to failure. Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. Thermal shock testing is performed to determine the ability of parts and components to withstand sudden changes in temperature. In this research, the main causes of failure of the feeder cable assembly were snapping, shorting and electro-pressure resistance failure. Using the Coffin-Manson model for ALT, the normal conditions were from Tmax = $80^{\circ}C$ to Tmin = $-40^{\circ}C$, the accelerated testing conditions were from Tmax = $120^{\circ}C$ to Tmin = $-60^{\circ}C$, the AF (Acceleration Factor) was 2.25 and the testing time was reduced from 1,000 cycles to 444 cycles. Using the Bxlife test, the number of samples was 5, the required life was B0.04%.10years, in the acceleration condition, 747 cycles were obtained. After the thermal shock test under different conditions, the feeder cable assembly was examined by a network analyzer and compared with the Weibull distribution modulus parameter. The results obtained showed good results in acceleration life test mode. For the same reliability rate, the testing time was decreased by a quarter using ALT.

• Korean Journal of Clinical Pharmacy
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• v.20 no.3
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• pp.213-220
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• 2010

Therapeutic duplication (TD) is a serious problem that frequently occurring primarily in the ambulatory setting in Korea. Implementation of concurrent drug utilization review (DUR) is a promising way to reduce inappropriate prescription and dispensing, and improve patient safety. This study was aimed to develop the process of DUR module of TD. Sixty-five drug ingredients classified into the drug category of the antipyretic, analgesic, and anti-inflammatory drug approved in Korea (The KFDA-dess nated classification codes of 114 or 264) were reviewed for this purpose. The drug ingredients (and products) were reclassified based on WHO's Anatomical, Therapeutic and Chemical (ATC) classification system. The clinical practice guidelines, textbooks and product labels on therapeutic uses of these drugs in Korea and several fores n countries were reviewed. If the drugs were categorized into the same therapeutically duplicable class, they were defined not to be used concurrently because the concurrent use was "therapeutically duplicated (unnecessary or even harmful)". Among the studied drug products, the following 5 drug classes were considto beas "therapeutic duplication": (1), on-t tooid DURnti-inflammatory drugs (NSAIDs, including s Dicylates), (2),Anilidts, (3),Opioids, (4) Ergot Dk Doids and (5) 5-$HT_1$ receptor agonot s. Therefore, concurrent prescribing or dispensing of more than 2 drug ingredients any in the above same classes should be considered as TD and needed to be warrant for careful review by pharmacists before dispensing.