• 한국공작기계학회논문집
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• 제16권3호
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• pp.56-63
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• 2007

Modern diesel vehicle has to comply with the EURO IV, V regulation with low level of particulate matter and smoke emission Moreover, emission standards of each countries are becoming stringent in advanced countries such as USA and Europe. Because Bio-diesel is similar to diesel fuel, it is essential to judge the environmental and health effects deriving from the use of Bio-diesel in diesel engine. The deterioration characteristics of emission in accordance with aging vehicles must be regulated for Bio-diesel. Therefore, under 1200 driving hours, 220,000km driving distance condition and full load, the deterioration characteristics of emission were estimated. We could reduce sulfur contents of fuel, particulate matter and smoke emission by using Bio-diesel and conform the influence of engine performance, emission, and fuel consumption by Bio-diesel deterioration

• 동력기계공학회지
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• 제13권1호
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• pp.65-71
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• 2009

To address the need for new intelligent sensing, this paper introduces nano sensors made of carbon nanotube (CNT) composites and presents their preliminary experiments. Having smart material properties such as piezoresistivity, chemical and bio selectivity, the nano composite can be used as smart electrodes of the nano sensors. The nano composite sensor can detect structural deterioration, chemical contamination and bio signal by means of its impedance measurement (resistance and capacitance). For a structural application, the change of impedance shows specific patterns depending on the structural deterioration and this characteristic is available for an in-situ multi-functional sensor, which can simultaneously detect multi symptoms of the structure. This study is anticipated to develop a new nano sensor detecting multiple symptoms in structural, chemical and bio applications with simple electric circuits.

• 보존과학연구
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• 통권24호
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• pp.5-28
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• 2003

Stone has been one of the most intensely studied materials in conservation. Understanding the deterioration of stone needs various knowledge in different mineralogical and physical characteristics and its weathering response under different climate and environment. The alteration and weathering of stone is affected by natural or artificial elements whether they are physical, chemical or biological damaging factors. It can be said that the bio deterioration of stone is coupled with every environmental factors, which induce decomposition of stone structure, either directly or indirectly as a form of catalysis. Many elements contribute to the deterioration of stone monuments and other objects of cultural value such as pagoda, stature of Buddha, etc. This report concentrates on the action of biodeteriorative factorsincluding bacteria, algae and higher plants. Preventive and remedial methods and a selection of chemical treatments are also described.

• 한국식품저장유통학회지
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• 제30권2호
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• pp.179-189
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• 2023

Consumers and industry experts frequently have negative perceptions of most chemical preservatives. Although most people concede that they cannot resolve global food waste issues without preservatives, they prefer products without chemical preservatives. Numerous emerging technologies is now surpassing conventional methods for mitigating microbial food deterioration in response to consumer demand and fundamental health and safety considerations, including biological antimicrobial systems such as using food-grade microorganisms and their metabolites primarily originating from microorganisms, plants, and animals. Microbial compounds, including bacteriocins, bacteriophages, and anti-fungal agents, plant extracts such as flavonoids and essential oils; and animal-originated compounds, such as lysozyme, chitosan, and lactoferrin, are considered some of the major bio-preservatives. These natural compounds can be used alone or with other preservatives to improve food safety. Hence, the use of microbes or their metabolic byproducts to extend the shelf life of foods while maintaining safety standards is known as bio-preservation. To manufacture and consume foods in a safe condition, this review primarily aims to broaden knowledge amongst industry professionals and consumers regarding bio-preservation techniques, bio-preservatives, their classifications, and distinctive mechanisms to enhance food safety.

• Ecology and Resilient Infrastructure
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• 제5권2호
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• pp.82-87
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• 2018

Proliferation of algae on the surface of concrete or mortar in aquatic habitat has a negative impact on maintenance of concrete-based structures. Growth of algae may decrease stability of structure by bio-deterioration. In this study, we developed a functional mortar for restraining bio-deterioration by using $Cu^{2+}$ ion. The mortar contains soluble glass beads made of $Cu^{2+}$ ion, which can dissolve into water slowly. Mortars prepared with different ratio of glass beads (0, 2, 5, 10, and 15%) were placed in a culture medium with algae and incubated over a month period. Water chemistry, chlorophyll-a, and extracellular enzyme activities were measured. The incubation was conducted in both freshwater and seawater conditions, to assess applicability to both aquatic conditions. Overall, mortar with Cu glass exhibited lower chlorophyll-a content, suggesting that the functional mortar reduced algal growth. DOC concentration increased because debris of dead algae increased. Cu glass also decreased phosphatase activity, which is involved in the regeneration of inorganic P from organic moieties. Since, P is often a limiting nutrient for algal production, algal growth may be inhibited. Activities of ${\beta}$-glucosidase and N-acetylglucosaminidase were not significantly affected because carbon and nitrogen mineralization may not be influenced by the Cu glass beads. Our study suggests that functional mortar with Cu glass beads may reduce the growth of algae on the surface, while it has little environmental impact.

• 원예과학기술지
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• 제33권5호
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• pp.697-704
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• 2015

본 연구는 절화 국화 'Baekma'를 일본으로 선박 수출 시 수송 환경을 분석하였으며, 절화 국화의 선도를 유지하기 위한 최적 전처리제를 구명하고자 하였다. 그 결과 일본으로 절화 국화를 수출시 약 3일~5일이 소요되었으며, 국내 이동, 선박 운송 및 일본 내에서 이동은 저온이 유지되었으나, 일본에서 검역시 상온에 노출되는 것으로 조사되었다. 이는 품질의 손상을 야기하는 것으로 수송 전체 기간동안 저온조건을 유지해야 할 것으로 판단되었다. 또한, 전처리제는 Chrysal RVB, NaOCl 처리구가 절화수명 연장에 효과적이었으며, Chrysal RVB 전처리는 절화 국화가 끝까지 만개하여 화형이 유지되었다. 박테리아 검정 결과 NaOCl, $ClO_2$ 처리구의 박테리아가 검출되지 않아 살균 성분이 세균증식을 막아준 것으로 판단되었다. 그러나 $ClO_2$처리구는 수확 후 초기 생육에 영향을 미치는 것으로 사료되었다. Chrysal RVB 처리 및 NaOCl 처리구의 엽록소 함유량이 가장 높은 것으로 조사되었다.

• Animal Bioscience
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• 제35권12호
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• pp.1871-1880
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• 2022

Objective: The primary goal was to identify the effectiveness of chemical or biological additives in delaying the deterioration of early-harvested wilted rye silage after exposure to air. Methods: Rye harvested as a whole plant at the early heading stage was wilted for 24 h. The wilted forage was divided into treatments including sodium diacetate (SDA) at 3 (SDA3) and 6 g/kg (SDA6), Lactobacillus plantarum (LP), L. buchneri (LB), or their equal mixture (LP+LB) at 1×10⁶ colony-forming unit/g fresh matter. Results: After 60 d of conservation in 20-L silos, lactic acid was greater in LP and LP+LB silages than other treatments (102 vs 90.2 g/kg dry matter [DM]). Acetic acid was greatest in SDA6 (32.0 g/kg DM) followed by LB (26.1 g/kg DM) and was lowest in LP treatment (4.73 g/kg DM). Silage pH was lower with microbial inoculation and the lowest and highest values were observed in LP and untreated silages, respectively. After 60 d, neutral detergent fiber concentration was lowest in SDA6 silages, resulting in the greatest in vitro DM digestibility (846 g/kg DM). Aerobic stability was longest in SDA6 (176 h) followed by LB treatment (134 h). Instability after aerobiosis was greatest in LP silages (68 h), about 8 h less than untreated silages. After aerobic exposure, yeast and mold numbers were lowest in SDA6 silages, resulting in DM loss minimization. Exhaustion of acetic acid and lactic acid after aerobic exposure was lowest with SDA6 but greatest with untreated and LP silages. Conclusion: Treatment of early-cut wilted rye forage with SDA at 6 g/kg resulted in silages with higher feeding value and fermentation quality, and substantially delayed deterioration after aerobic exposure, potentially qualifying SDA at this load for promotion of silage quality and delaying aerobic spoilage of early-harvested (low DM) rye forage.

• 한국식품영양학회지
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• 제33권6호
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• pp.614-623
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• 2020

The objective of this study was to produce a nutrient delivery system (NDS) using sialic acid extracted from edible bird's nest (EBN), which improves brain function in patients with Alzheimer's disease and Parkinson's disease, by affinity bead technology (ABT). The inhibitory activity of acetylcholinesterase (AChE) and pyramidal cells in the dentate gyrus of the hippocampus were analyzed to investigate the effect of a sialic acid NDS on Alzheimer's disease. Also, the effect of a sialic acid NDS on Parkinson's disease was evaluated by rota-rod test and pole test in an animal model. Among the groups treated with donepezil, EBN, and sialic acid NDS, the AChE activity was the lowest in the sialic acid NDS-treated group. The results of the hippocampus analysis of the rat model confirmed that the sialic acid NDS inhibited amyloid-beta accumulation depending upon the concentration. Also, the sialic acid NDS group showed more improvement in motor deterioration than the1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced group in both the rota-rod test and pole test. Therefore, the sialic acid NDS had an effect of protecting not only Alzheimer's disease by inhibiting AChE and amyloid-beta accumulation, but Parkinson's disease by preventing neurotoxicity induced by MPTP.

• 한국농공학회논문집
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• 제64권6호
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• pp.77-86
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• 2022

Various odor reduction systems are being operated at pig houses to improve livestock odor issues. However, the quantitative evaluation of odor reduction efficiency is not sufficiently conducted. The analysis of factors that affect the reduction efficiency also has not been sufficiently conducted. Therefore, in this study, the reduction efficiency of representative odor reduction facilities (bio-curtain, scrubber) operated by domestic pig houses was evaluated. The odor reduction efficiency was evaluated by sampling the air before and after the odor reduction facility in 6 pig houses. Livestock odors were evaluated for complex odors, ammonia, hydrogen sulfide, and VOC. To find factors for reduction efficiency, temperature, humidity, pH of washing resolution, type of washing water, and ventilation rate was measured. As a result, it was found that the scrubber system had the highest reduction efficiency. The reduction efficiency was found to be affected by the scrubber's washing resolution, filler, operating conditions, and size. Bio-curtains may have problems such as deterioration of fan performance due to ventilation fan load, groundwater pollution, and excessive use of groundwater.

• Journal of information and communication convergence engineering
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• 제8권2호
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• pp.173-179
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• 2010

Over recent years, much research attention has been devoted to a two-factor authentication mechanism which integrates both tokenized pseudorandom numbers with user specific biometric features for biometric verification, known as Biohash. The main advantage of Biohash over sole biometrics is that Biohash is able to achieve a zero equal error rate and provide a clean separation of the genuine and imposter populations, thereby allowing elimination of false accept rates without imperiling the false reject rates. Nonetheless, when the token of a user is compromised, the recognition performance of a biometric system drops drastically. As such, a few solutions have been proposed to improve the degraded performance but such improvements appear to be insignificant. In this paper, we investigate and pinpoint the basis of such deterioration. Subsequently, we propose a two-level approach by utilizing strong inner products and fuzzy logic weighting strategies accordingly to increase the original performance of Biohash under this scenario.