• 한국산업융합학회 논문집
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• 제22권1호
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• pp.1-9
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• 2019

In electric agricultural machine the gearbox is used to increase torque and lower the output speed of the motor shaft. The gearbox consists of several shafts, helical gears and spur gears works in series. Optimization plays an important role in gear design as reducing the weight or volume of a gear set will increase its service life and improve the bearing capacity. In this paper the basic design parameters for gear like shaft diameter and face width are considered as the input variables. The bending stress and material volume is considered as the objective function. ANSYS was used to investigate the bending stress when the variable was changed. Artificial Neural Network (ANN) was used to obtain the mathematical model of the system based on the bending stress behaviour. The ANN was used since the output system is nonlinear. The Genetic Algorithm (GA)　technique of optimization is used to obtain the optimized values of shaft diameter and face width on the pinion based on the ANN mathematical model and the results are compared as that obtained using the traditional method. The ANN and GA were performed using MATLAB. The simulation results were shown that the proposed algorithm was successfully calculated the value of shaft diameter and face width to obtain the minimal bending stress and material volume of the gearbox.

• 농업과학연구
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• 제47권4호
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• pp.1049-1056
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• 2020

Ultrafine dust causes asthma and respiratory and cardiovascular diseases when inhaled. Ammonia (NH3) plays a big role in ultrafine dust formation in the atmosphere by reacting with nitrogen oxides (NOx) and sulfur oxides (SOx) emitted from various sources. The agricultural sector is the single largest contributor of NH3, with the vast majority of emissions ensuing from fertilizers and livestock sector. Interest in using biochar to attenuate these NH3 emissions has grown. This experiment was conducted to study the effects of using rice hull biochar pyrolyzed at three different temperatures of 250℃ (BP 4.6, biochar pH 4.6), 350℃ (BP 6.8), and 450℃ (BP 10.3) on the emission of ammonia from soil fertilized with urea. The emissions of NH3 initially increased as the experiment progressed but decreased after peaking at the 84th hour. The amount of emitted NH3 was lower in soil with biochar amendments than in that without biochar. Emissions amongst biochar-amended soils were lowest for the BP 6.8 treatment, followed in an ascending order by BP 10.3 and BP 4.6. Since BP 6.8 biochar with neutral pH resulted in the lowest amount of NH3 emitted, it can be concluded that biochar's pH has an effect on the emissions of NH3. The results of this study, therefore, indicate that biochar can abate NH3 emissions and that a neutral pH biochar is more effective at reducing gaseous emissions than either alkaline or acidic biochar.

• 한국약용작물학회지
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• 제28권6호
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• pp.445-454
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• 2020

Background: Culturing wild ginseng adventitious root using plant factory technology provides genetic safety and high productivity. This production technology is drawing attention in the fields of functional raw materials and product development. The cultivation method using elicitors is key technology for controlling biomass and increasing secondary metabolites. Methods and Results: Elicitor treatments using methyl jasmonate, pyruvic acid, squalene, β-sistosterol were performed to amplify total ginsenosides (Rb1, Rc, Rb2, Rb3, and Rd) of cultured wild ginseng adventitious root. Thereafter, fermentation and steaming processes were performed to convert total ginsenosides into minor molecular ginsenosides (Rg3, Rk1, and Rg5). The result indicated that methyl jasmonate minimizes the reduction in fresh weight of cultured wild ginseng adventitious root and maximizes total ginsenosides (sum of Rb1, Rc, Rb2, Rb3, and Rd). Ginsenoside conversion results showed a maximum degree of conversion of 131 mg/g. Conclusions: In this study, we demonstrated that the optimal elicitor treatment method increased the content of total ginsenosides, while the steaming and fermentation processing method increased the content of minor ginsenosides.

• 한국군사과학기술학회지
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• 제25권4호
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• pp.434-442
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• 2022

Highly toxic chemical warfare agents(CWA) could be used in chemical warfare and terrorism. The protection of skin is crucial for civilians and soldiers, because the primary routes of exposure to CWA are inhalation and skin absorption. Thus, topical skin protectants(TSP) have been studied and developed in many countries to complement protective equipments. In this study, in-vitro test procedure was optimized and established using a flow-through diffusion cell system containing excised hairless mouse skin in an attempt to assess the effectiveness of various TSP formulations against nerve agent simulants. In addition, the test results on the formulations including the ingredients used in SERPACWA(Skin Exposure Reduction Paste Against Chemical Warfare Agent) and IB-1(TSP of Israel) were included, indicating that the formulations with perfluorinated compounds were more effective than the glycerin-based formulations.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.609-628
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• 2015

Thie study presents the biomass-derived jet (bio-jet) fuel production technologies for greenhouse gas (GHG) reduction in aviation sector. The aviation sector is responsible for the 2% of the world anthropogenic $CO_2$ emissions and the 10% of the fuel consumption: airlines' costs for fuel reach 30% of operating costs. In addition, the aviation traffic is expected to double within 15 years from 2012, while fuel consumption and $CO_2$ emissions should double in 25 years. Biojet fuels have been claimed to be one of the most promising and strategic solutions to mitigate aviation emissions. This jet fuel, additionally, must meet ASTM International specifications and potentially be a100% drop-in replacement for current petroleum jet fuel. In this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways are reviewed for process, economic analysis and life cycle assessment (LCA) on conversion pathways to bio-jet fuel.

• Journal of Applied Biological Chemistry
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• 제59권3호
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• pp.173-178
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• 2016

Phenyllactic acid (PLA), which is a known antimicrobial compound, can be synthesized through the reduction of phenylpyruvic acid (PPA) by lactate dehydrogenase of lactic acid bacteria (LAB). PLA-producing LAB was isolated from coffee beans, and the isolated LAB was identified as Lactobacillus zeae Y44 by 16S rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. zeae Y44 was assessed for both its capability to produce the antimicrobial compound PLA and its antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Colletotrichum aculatum). PLA concentration was found to be 4.21 mM in CFS when L. zeae Y44 was grown in MRS broth containing 5 mM PPA for 12 h. PLA production could be promoted by the supplementation with PPA and phenylalanine (Phe) in the MRS broth, but not affected by 4-hydroxy-phenylpyruvic acid, and inhibited by tyrosine as precursors. Antifungal activity assessment demonstrated that all fungal pathogens were sensitive to 5 % CFS (v/v) of L. zeae Y44 with average growth inhibitions ranging from 27.8 to 50.0 % (p<0.005), in which R. solani was the most sensitive with an inhibition of 50.0 %, followed by B. cinerea and C. aculatum. However, pH modification of CFS to pH 6.5 caused an extreme reduction in their antifungal activity. These results may indicate that the antifungal activity of CFS was caused by acidic compounds like PLA or organic acids rather than proteins or peptides molecules.

• Journal of Periodontal and Implant Science
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• 제40권1호
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• pp.25-32
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• 2010

Purpose: The performance of implant surgery in the posterior maxilla often poses a challenge due to insufficient available bone. Sinus floor elevation was developed to increase the needed vertical height to overcome this problem. However, grafting materials used for the sinus lift technique eventually show resorption. The present study radiographically compared and evaluated the changes in height of the grafting materials after carrying out maxillary sinus elevation with a window opening procedure. This study also evaluated the difference between two xenogenic bone materials when being used for the sinus lifting procedure. Methods: Twenty-one patients were recruited for this study and underwent a sinus lift procedure. All sites were treated with either bovine bone (Bio-$Oss^{(R)}$) with platelet-rich plasma (PRP) or bovine bone (OCS-$B^{(R)}$)/PRP. A total of 69 implants were placed equally 6-8 months after the sinus lift. All sites were clinically and radiographically evaluated right after the implant surgery, 7-12 months, 13-24 months, and 25-48 months after their prosthetic loading. Results: Changes of implant length/bone length with time showed a statistically significant decreasing tendency (P<0.05). There was no significant change in the Bio-$Oss^{(R)}$ group (P>0.05). In contrast, the OCS-$B^{(R)}$ group showed a significant decrease with time (P<0.05). However, no significant difference was observed between the two groups (P>0.05). Conclusions: The results showed that there was significant reduction in comparison with data right after placement, after 7 to 12 months, 13 to 24 months, and over 25 months; however, reduction rates between each period have shown to be without significance. No significant difference in height change was observed between the Bio-$Oss^{(R)}$ and the OCS-$B^{(R)}$ groups.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.62-72
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• 2015

This study investigates the in-situ implementation of bio-regenerated iron mineral catalyst to remove explosive compounds in ground water at a military shooting range in operation. A bio-regenerated iron mineral catalyst was synthesized using lepidocrocite (iron-bearing soil mineral), iron-reducing bacteria Shewanella putrefaciens CN32, and electron mediator (riboflavin) in the culture medium. This catalyst was then injected periodically in the ground to build a redox active zone acting like permeable reactive barrier through injection wells constructed at a live fire military shooting range. Ground water and core soils were sampled periodically for analysis of explosive compounds, mainly RDX and its metabolites, along with toxicity analysis and REDOX potential measurement. Results suggested that a redox active zone was formed in the subsurface in which contaminated ground water flows through. Concentration of RDX as well as toxicity (% inhibition) of ground water decreased in the downstream compared to those in the upstream while concentration of RDX reduction products increased in the downstream.

• The Plant Pathology Journal
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• 제25권3호
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• pp.263-269
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• 2009

Bacterial wilt, Fusarium wilt and Foot rot caused by Ralstonia solanacearum, Fusarium oxysporum, and Phytophthora capsici respectively, continue to be severe problems to tomato, potato and black pepper growers in Vietnam. Three bio-products, Bacillus vallismortis EXTN-1 (EXTN-1), Bacillus sp. and Paenibacillus sp. (ESSC) and Bacillus substilis (MFMF) were examined in greenhouse bioassay for the ability to reduce bacterial wilt, fusarium wilt and foot rot disease severity. While these bio-products significantly reduced disease severities, EXTN-1 was the most effective, providing a mean level of disease reduction 80.0 to 90.0% against bacterial wilt, fusarium wilt and foot rot diseases under greenhouse conditions. ESSC and MFMF also significantly reduced fusarium wilt, bacterial wilt and foot rot severity under greenhouse conditions. Bio-product, EXTN-1 with the greatest efficacy under greenhouse condition was tested for the ability to reduce bacterial wilt, fusarium wilt and foot rot under field condition at Song Phuong and Thuong Tin locations in Ha Tay province, Vietnam. Under field condition, EXTN-1 provided a mean level of disease reduction more than 45.0% against all three diseases compared to water treated control. Besides, EXTN-1 treatment increased the yield in tomato fruits 17.3% than water treated control plants.

• 한국분무공학회지
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• 제19권3호
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• pp.115-122
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• 2014

As a demand for an automobile increases, air pollution and a problem of the energy resources come to the fore in the world. Consequently, governments of every country established ordinances for green-house gas reduction and improvement of air pollution problem. Especially, as international oil price increases, engine using clean energy are being developed competitively with alternative transportation energy sources development policy as the center. Bio ethanol, one of the renewable energy produced from biomass, gained spotlight for transportation energy sources. Studies are in progress to improve fuel supply methods and combustion methods which are key features, one of the engine technologies. DI(Direct Injection), which can reduce fuel consumption rate by injecting fuel directly into the cylinder, is being studied for Green-house gas reduction and fuel economy enhancement at SI(Spark Ignition). GDI(Galoine Direct Injection) has an advantage to meet the regulations for fuel efficiency and $CO_2$ emissions. However it produces increased number of ultrafine particles, that yet received attention in the existing port-injection system, and NOX. As fuel is injected into the cylinder with high-pressure, a proper injection strategy is required by characteristics of a fuel. Especially, when alcohol type fuel is considered. In this study, we tried to get a base data bio-ethanol mixture in GDI, and combustion for optimization. We set fuel mixture rate and fuel injection pressure as parameters and took a picture with a high speed camera after gasoline-ethanol mixture fuel was injected into a constant volume combustion chamber. We figured out spraying characteristic according to parameters. Also, we determine combustion characteristics by measuring emissions and analyzing combustion.