• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.123-130
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• 2023

As part of the research on cultural factors that determine international tourism demand, this study was conducted based on regional interest and the need for understanding religion. The purpose of this study is to empirically test how religious factors affect tourism demand in Korea to find out that religious factors are important considerations in establishing tourism policies and strategies. To achieve the purpose of this study, the research target areas were selected as Thailand, Indonesia, and the Philippines, which have relatively many tourists visiting Korea among Southeast Asian countries and are well known for their religious characteristics. GDP and nominal exchange rate, which are economic factors, were selected as explanatory variables. And religious diversity was selected as a characteristic factor variable of the tourism demand model based on the characteristic theory. An empirical analysis was conducted through a gravity model. As a result of the estimation, it was found that GDP has a positive effect on tourism demand in Korea. Nominal exchange rate variables and religious diversity variables were found to have a negative effect on tourism demand in Korea. We have confirmed that religion is an important factor in choosing tourist destinations for Filipino, Thai, and Malaysian tourists visiting Korea, and they choose religiously similar destinations.

• Clean Technology
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• v.30 no.1
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• pp.28-36
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• 2024

As demand for electric vehicles increases, the market for lithium-ion batteries is also rapidly increasing. The battery life of lithium-ion batteries is limited, so waste lithium-ion batteries are inevitably generated. Accordingly, lithium was selectively preleached from waste lithium iron phosphate (LiFePO₄, hereafter referred to as the LFP) cathode material powder among lithium ion batteries, and iron phosphate (FePO₄) powder was recovered. The recovered iron phosphate powder was mixed with alkaline sodium carbonate (Na₂CO₃) powder and heat treated to confirm its crystalline phase. The heat treatment temperature was set as a variable, and then the leaching rate and powder characteristics of each ingredient were compared after water leaching using Di-water. In this study, lithium showed a leaching rate of approximately 100%, and in the case of powder heat-treated at 800 ℃, phosphorus was leached by approximately 99%, and the leaching residue was confirmed to be a single crystal phase of Fe₂O₃. Therefore, in this study, lithium, phosphorus, and iron components were individually separated and recovered from waste LFP powder.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.370-377
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• 2014

Research was initiated to evaluate cool-season grass (CSG) overseeding effects on coverage and species transition in Korean lawngrass (Zoysia japonica Steud.) and to determine CSGs and their seeding rate for a practical overseeding. Treatments were comprised of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), tall fescue (TF, Festuca arundinacea Schreb.) and their mixtures. Significant differences were observed in turfgrass coverage and species transition. Since overseeding, the coverage was highest in PR, followed by TF and lowest in KB. The highest coverage in polystand was associated with Mixture IV (TF 50 + PR 50) at a seeding rate of $150gm^{-2}$ which had highest PR and TF, but without KB. Regarding turfgrass transition, zoysiagrass recovery continued to come back up to 80% from late March. But it reduced after early October. Zoysiagrass in monostand was greatest in KB and lowest in TF, but variable in polystand. For the fast and great coverage in winter, it would be the best to apply with PR at $100gm^{-2}$ and equal combination of PR and TF by 1/2 in the mixture at $150gm^{-2}$. For the smooth spring transition to zoysiagrass, however, KB application at $50gm^{-2}$ is recommended.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.10-21
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• 2006

The aim in this study is to develop the combined EGR system with a non-thermal plasma reactor for reducing exhaust emissions and improving fuel economy in turbo intercooler ECU common-rail diesel engines. At the first step, in this paper, the characteristics of performance and $NO_x{\cdot}THC$ emissions under four kinds of engine loads are experimentally investigated by using a four-cycle, four-cylinder, direct injection type, water-cooled turbo intercooler ECU common-rail diesel engine with a combined plasma exhaust gas recirculation(EGR) system operating at three kinds of engine speeds. The EGR system is used to reduce $NO_x$ emissions, and the non-thermal plasma reactor and turbo intercooler system are used to reduce THC emissions. The plasma system is a flat-to-flat type reactor operated by a plasma power supply. The fuel is sprayed by pilot and main injections at the variable injection timing between BTDC $15^{\circ}$ and ATDC $1^{\circ}$ according to experimental conditions. It is found that the specific fuel consumption rate with EGR is increased, but the fuel economy is better than that of mechanical injection type diesel engine as compared with the same output. Results show that $NO_x$ emissions are decreased, but THC emissions are increased, as the EGR rate is elevated. $NO_x$ and THC emissions are also slightly decreased as the applied electrical voltage of the non-thermal plasma reactor is elevated. Thus one can conclude that the influence of EGR in $NO_x$ and THC emissions is larger than that of the non-thermal plasma reactor, but THC emissions are greatly influenced by the non-thermal plasma reactor as the EGR rate is elevated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.1
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• pp.15-20
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• 2011

[ $^7Li$ ]Magic Angle Spinning (MAS) NMR spectroscopy has been used to study the lithium local environments in $Li_4P_2O_7$ and$LiFePO_4$ materials. The purpose of this study was to know the structure of the solid electrolyte interphase (SEI) in lithium ion cells composed of $LiFePO_4$ as cathode material. $Li_4P_2O_7$ and $LiFePO_4$ were prepared by a solid-state reaction. The $^7Li$ MAS NMR experiments were carried out at variable temperatures in order to observe the local structure changes at the temperatures in $Li_4P_2O_7$ system. The $^7Li$ MAS NMR spectra of in $Li_4P_2O_7$ indicate that the lithium local environments in $Li_4P_2O_7$ were not changed in the temperature range between $27^{\circ}C$ and $97^{\circ}C$ Through this work, we confirmed that the small amount of $Li_4P_2O_7$ less than 5.0 wt% in $LiFePO_4$ could be clearly measured by the $^7Li$ MAS NMR spectroscopy at high spinning rate over than 11 kHz.

• Journal of Multimedia Information System
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• v.5 no.4
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• pp.235-244
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• 2018

Potential maximum soil moisture retention (S) is a dominant parameter in the Soil Conservation Service (SCS; now called the USDA Natural Resources Conservation Service (NRCS)) runoff Curve Number (CN) method commonly used in hydrologic modeling for event-based flood forecasting (SCS, 1985). Physically, S represents the depth [L] soil could store water through infiltration. The depth of soil moisture retention will vary depending on infiltration from previous rainfall events; an adjustment is usually made using a factor for Antecedent Moisture Conditions (AMCs). Application of the method for continuous simulation of multiple storms has typically involved updating the AMC and S. However, these studies have focused on a time step where S is allowed to vary at daily or longer time scales. While useful for hydrologic events that span multiple days, this temporal resolution is too coarse for short-term applications such as flash flood events. In this study, an approach for deriving a time-variable potential maximum soil moisture retention curve (S-curve) at hourly time-scales is presented. The methodology is applied to the Napa River basin, California. Rainfall events from 2011 to 2012 are used for estimating the event-based S. As a result, we derive an S-curve which is classified into three sections depending on the recovery rate of S for soil moisture conditions ranging from 1) dry, 2) transitional from dry to wet, and 3) wet. The first section is described as gradually increasing recovering S (0.97 mm/hr or 23.28 mm/day), the second section is described as steeply recovering S (2.11 mm/hr or 50.64 mm/day) and the third section is described as gradually decreasing recovery (0.34 mm/hr or 8.16 mm/day). Using the S-curve, we can estimate the hourly change of soil moisture content according to the time duration after rainfall cessation, which is then used to estimate direct runoff for a continuous simulation for flood forecasting.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1030-1035
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• 2012

In this research, we analysed design and CFD analysis of an inflow radial turbine for OTEC with an output power of 8kW using an working fluid of ammonia. The inflow radial turbine consists of scroll casing, vain nozzle with 18 blade numbers and rotor blade with 13 blade numbers. Mass flow rate, and inlet temperature are 0.5kg/s and $25^{\circ}C$ respectively, and variable rotational speeds were applied between 12,000 and 36,000 with 3,000 rpm intervals. As the results according to the rotational speeds, the designed speed is 24,000 rpm where maximum efficiency exists. The maximum efficiency and output power are 88.66% and 8.52kW, respectively. Through this study, we expect that the analysed results will be used as the design material for the composition of the turbine optimal design parameters corresponding to the target output power under various working material conditions.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.453-460
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• 2011

This study was carried out to test a red pepper tedding factors which is needed for design and development of an auto-tedding machine and a performance. According to this test, the results can be summarized as follows: The results of the tedding factors test according to shape of rotary blade, which is the 0.4 to 0.5 mm brush type, was found to be the most appropriate. As a result of tedding ratio which includes brush diameters, driving velocities and rotation velocities, there was generally no significance difference, but the red pepper tedding efficiency was found to be 39.7%. The moisture drying rate of red pepper was found to be 0.9 %w.b./h in prototype auto-tedding machine and 0.4 %w.b./h in traditional practice. The drying time was found to be 3 days in prototype auto-tedding machine and the traditional practice was 6 days. The average variable coefficient of the red pepper moisture content was found to be 16.8% in prototype auto-tedding machine in comparing with the traditional practice of 35.0%. This test showed a difference around two times, and this difference was evaluated to be the reason for irregular drying and different drying times.

• Parasites, Hosts and Diseases
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• v.58 no.3
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• pp.229-236
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• 2020

Cutaneous leishmaniosis (CL) is the most common form of leishmaniasis.CL caused by L. major and L. tropica is endemic in 17 provinces of Iran. This study was carried out to elucidate situation of CL in Ardabil province and to predict distribution of Phlebotomus papatasi and Phlebotomus sergenti (Diptera: Psychodidae) as vectors of CL in the region. In this cross-sectional study, data on CL patients were collected from local health centers of Ardabil province, Iran during 2006-2018 to establish a geodatabase using ArcGIS10.3. A total of 20 CL cases were selected randomly and skin samples were collected and analyzed by PCR method. MaxEnt 3.3.3 model was used to determine ecologically suitable niches for the main vectors. A total, 309 CL human cases were reported and the highest incidence rate of disease was occurred in Bilasavar (37/100,000) and Germi (35/100,000). A total of 2,794 sand flies were collected during May to October 2018. The environmentally suitable habitats for P. papatasi and P. sergenti were predicted to be present in northern and central areas of Ardabil province. The most variable that contributed ratio in the modeling were Isothermality and slope factors. Ardabil province is possibly an endemic are for CL. The presence of P. papatasi and P. sergenti justifies local transmission while the vectors of CL are existing in the northern and central areas of the province.

• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.681-688
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• 2005

The high-temperature deformation mechanisms of a ${\alpha}+{\beta}$ titanium alloy (Ti-6Al-4V), near-a titanium alloy (Ti-6.85Al-1.6V) and a single-phase a titanium alloy (Ti-7.0Al-1.5V) were deduced within the framework of inelastic-deformation theory. For this purpose, load relaxation tests were conducted on three alloys at temperatures ranging from 750 to $950^{\circ}C$. The stress-versus-strain rate curves of both alloys were well fitted with inelastic-deformation equations based on grain matrix deformation and grain-boundary sliding. The constitutive analysis revealed that the grain-boundary sliding resistance is higher in the near-${\alpha}$ alloy than in the two-phase ${\alpha}+{\beta}$ alloy due to the difficulties in relaxing stress concentrations at the triple-junction region in the near-${\alpha}$ alloy. In addition, the internal-strength parameter (${\sigma}^*$) of the near-${\alpha}$ alloy was much higher than that of the ${\alpha}+{\beta}$ alloy, thus implying that dislocation emission/ slip transfer at ${\alpha}/{\alpha}$ boundaries is more difficult than at ${\alpha}/{\beta}$ boundaries.