• Journal of the Korean Wood Science and Technology
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• v.52 no.1
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• pp.1-12
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• 2024

Betung bamboo (Dendrocalamus asper) is used as a building and handicraft material in Indonesia; however, bamboo needs to be dried to increase its stability. This study aimed to evaluate the efficiency of drying bamboo using solar energy and different drying oven designs. The betung bamboo pieces were dried using a direct solar dryer (direct drying) and an indirect solar dryer (indirect drying) and then the decrease in levels that occurred based on the relative humidity (RH) and temperature values achieved in the two dryers were compared. The highest average temperature in the direct indirect drying oven compartment was 60.1 ± 13.1℃ with 19.9 ± 16.4% RH and 60.2 ± 11.9℃ with 19.5 ± 15.5% RH, respectively. The drying defect in indirect drying was lower than that in direct drying, and indirect drying had a 61.7% greater average water loss than direct drying with significant difference (95%, analysis of variance) based on water loss/compartment volume parameters. Thus, the solar drying oven can be used to air-dry bamboo (14%) for 7 d from an initial moisture content of 70%-80% in bamboo strips. The results of this research can be used for small-scale bamboo processing industries that have limited use of electrical energy with quite good results.

• Journal of the Korean Institute of Rural Architecture
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• v.26 no.3
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• pp.11-18
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• 2024

As the complexity and diversity of modern urban development increases, the importance of external space planning in urban development projects is growing. This study analyzes the importance and characteristics of each major to enhance the utility value of external space, which aims to improve the efficiency of external space planning and ultimately improve the quality of life of residents. To this end, we reviewed relevant literature, legal guidelines, checklists, and guidelines, and derived 17 external space indicators through expert surveys and FGIs, and organized them into five major categories: accessibility, connectivity, suitability, stability and locality, and landscape planning through FGIs with experts in architecture, urbanism, and landscape architecture. As a result of the analysis, urban planning and design majors prioritized planning that considers the hierarchy and characteristics of the landscape structure, securing public space through the connection of open spaces and pedestrian paths, and connecting organic and three-dimensional buildings, streets, and parks; architectural planning and design majors prioritized harmony with the surrounding environment, securing public space through the connection of open spaces and pedestrian paths, and connecting organic and three-dimensional buildings, streets, and parks; and landscape (environmental) and landscape majors prioritized harmony with the surrounding environment, connecting with adjacent buildings, streets, parks, and green spaces, and planning with integrated landholdings. This emphasizes that urban development projects should secure publicness and integration through harmonious connections with adjacent buildings, streets, parks, and green spaces. This study developed evaluation indicators for evaluating the external space planning of urban development projects and quantified them through the hierarchical analysis method (AHP), which will be useful for future policy formulation and practical application in the fields of urban planning and design, architectural planning and design, landscape (environment), and landscape architecture.

• Tribology and Lubricants
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• v.40 no.4
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• pp.111-117
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• 2024

Due to global CO₂ emission reductions and fuel efficiency regulations, the trend toward transitioning from internal combustion engine vehicles to electric vehicles (EVs) has accelerated. Consequently, the problem of EV failures has become a focal point of active research. The parasitic capacitance generated during motor-shaft rotation induces voltage that deteriorates the raceway and ball surfaces of bearings, causing electrical damage in EVs. Despite numerous attempts to address this issue, most studies have been conducted under high viscosity lubricant and low load conditions. However, due to factors such as high-speed operation, rapid acceleration and deceleration, motor heating, and motor system-decelerator integration, current EV applications have shown diminished stability in lubrication films of motor bearings, thereby leveraging the investigation to address the risk of electrical damage. This study investigates the electrical damage to rolling bearing elements in EV motor drive systems. The experimental analysis focuses on the effects of electric currents and operational loads on bearing integrity. A test rig is designed to generate high-rate voltage specific to a motor system's parasitic capacitance, and bearing samples are exposed to these currents for specified durations. Component evaluation involves visual inspections and vibration measurements. In addition, a predictive model for electrical failure is developed based on accumulated data, which demonstrates the ability to predict the likelihood of electrical failure relative to the duration and intensity of current exposure. This in turn reduces uncertainties in practical applications regarding electrical erosion modes.

• Journal of agricultural medicine and community health
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• v.49 no.3
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• pp.235-256
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• 2024

Background: The adequate provision of medical care relies on the availability of a suitable number of healthcare professionals. To ensure stability in healthcare delivery, it is crucial for a country to accurately estimate and address the supply of doctors. This study aims to contribute to the formulation of effective policies for securing and distributing doctor manpower, with a focus on medically underserved areas at both the national and local government levels. Methods: Employing the system dynamics methodology, this research utilizes stock and flow diagrams, including level and rate diagrams, to quantitatively analyze the cumulative structure of the doctor supply and demand system. Results: The analysis reveals a substantial shortage of clinical doctors in Gyeongsangnam-do, amounting to 15,477 as of 2021. Projections indicate a need for an additional 7,570 doctors by the year 2050 to maintain the current healthcare service level. Examination of medical treatment rights and distribution across cities and counties indicates an insufficiency in doctor supply relative to demand in the majority of regions. Alternative scenarios, such as increasing medical school enrollments and adjusting retirement ages, were explored, yet none provided a sufficient resolution to the shortage. Conclusion: The findings underscore an impending exacerbation of the doctor shortage in Gyeongsangnam-do if the existing system is perpetuated. Addressing this issue necessitates not only augmenting the number of medical school students and adapting retirement age policies but also implementing diverse strategies employed successfully in other countries. This study serves as a foundational step in informing evidence-based policies aimed at securing an ample and appropriately distributed doctor workforce for sustainable healthcare delivery.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.581-591
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• 2023

Domestic processed food exports might increase due to the free trade agreement (FTA) and spread of the Korean Wave, Hallyu. However, the share of the domestic raw materials in the domestic processed food industry is very low at 31.4%, which limits the spillover effect on domestic agriculture. Therefore, we selected frozen dumplings as a representative processed food whose exports are growing rapidly and conducted a multiple regression analysis to examine the effects of Hallyu and FTA variables on the frozen dumpling exports. We tried to link them to an increase in agricultural income through the expansion of demand for the domestic raw materials. This study analyzed tariff indicator as the FTA variable, cosmetics export value indicator as the Hallyu Wave variable, and other variables expected to change the trade environment such as gross domestic product (GDP) and the relative exchange rate by country as the key explanatory variables that affect changes in the trade environment. The analysis showed that the core hypothesis, the Hallyu variable and the FTA variable, have a positive impact on frozen dumpling exports. Frozen dumpling exports are expected to increase as the FTAs and the spread of Hallyu are expected to continue for the foreseeable future. Therefore, we should seek ways to increase the proportion of domestically produced ingredients in the frozen dumplings to spread the economic impact to domestic agriculture. We reviewed previous studies and determined, the price-related factors play a major role in the use of imported ingredients, and that price stability and competitiveness are essential to increase the share of the domestically produced ingredients. Based on these conclusions, we reviewed the current status of food industry-related policies and determined measures needed to expand the use of domestically produced ingredients.

• Geotechnical Engineering
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• v.12 no.4
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• pp.157-178
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• 1996

Current design methods for reinforced earth structures take no account of the magnitude of the strains induced in the tensile members as these are invariably manufactured from high modulus materials, such as steel, where straits are unlikely to be significant. With fabrics, however, large strains may frequently be induced and it is important to determine these to enable the stability of the structure to be assessed. In the present paper internal design method of analysis relating to the use of fabric reinforcements in reinforced earth structures for both stress and strain considerations is presented. For the internal stability analysis against rupture and pullout of the fabric reinforcements, a strain compatibility analysis procedure that considers the effects of reinforcement stiffness, relative movement between the soil and reinforcements, and compaction-induced stresses as studied by Ehrlich 8l Mitchell is used. I Bowever, the soil-reinforcement interaction is modeled by relating nonlinear elastic soil behavior to nonlinear response of the reinforcement. The soil constitutive model used is a modified vertsion of the hyperbolic soil model and compaction stress model proposed by Duncan et at., and iterative step-loading approach is used to take nonlinear soil behavior into consideration. The effects of seepage pressures are also dealt with in the proposed method of analy For purposes of assessing the strain behavior oi the fabric reinforcements, nonlinear model of hyperbolic form describing the load-extension relation of fabrics is employed. A procedure for specifying the strength characteristics of paraweb polyester fibre multicord, needle punched non-woven geotHxtile and knitted polyester geogrid is also described which may provide a more convenient procedure for incorporating the fablic properties into the prediction of fabric deformations. An attempt to define improvement in bond-linkage at the interconnecting nodes of the fabric reinforced earth stracture due to the confining stress is further made. The proposed method of analysis has been applied to estimate the maximum tensions, deformations and strains of the fabric reinforcements. The results are then compared with those of finite element analysis and experimental tests, and show in general good agreements indicating the effectiveness of the proposed method of analysis. Analytical parametric studies are also carried out to investigate the effects of relative soil-fabric reinforcement stiffness, locked-in stresses, compaction load and seepage pressures on the magnitude and variation of the fabric deformations.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.1
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• pp.63-70
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• 2015

An inter-laboratory comparison campaign on nutrient analysis in seawater was carried out in 2010. Sets of three sterilized seawater samples (Bottle 130, 131, 132) which have enough homogeneity and stability were distributed to 10 laboratories. Participants analyzed the nutrients in their own laboratories (nitrite, nitrate, phosphate, and silicate) at least 5 times and reported the results. Statistical treatments were applied to the results to assess the precision for each laboratory and the discrepancy among laboratories. Most laboratories show within 10% of precision in all nutrient results. Degrees of scattering described as discrepancy among laboratories and relative percent difference values were 4~63% and 0.04~2217%, respectively. The statistical analysis shows that the difference among the laboratories may due to the systematic error rather than random error. When the results were corrected by the results of bottle 130 as a reference material, the degrees of scattering and the relative percent difference were improved significantly. As a result, since most participants show satisfactory precision for nutrient analyses, a use of reference materials which have homogeneity and stability was strongly recommended to improve the comparability of nutrient data.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.621-630
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• 2021

This study evaluated cracks and climate monitoring in Ipseok-dae columnar joints and Jigong Neodeol rock blocks in Mudeungsan National Park. The rocks' state of cracking and their surface temperatures were measured alongside air temperature, relative humidity, and wind velocity. The maximum crack behavior in Ipseok-dae was 0.367 mm at one point, and showed a slight tendency at other points. One in Jigong Neodeol was within 0.15 mm and showed a stable state with little change. The surface temperature of the Ipseok-dae columnar joints was higher on the side exposed to sunlight than on the shaded side. All blocks of Jigong Neodeol rock showed similar temperatures. The air temperature showed a similar distribution for both rock types. The air temperature showed a similar distribution for both Ipseok-dae and Jigong Neodeol. The relative humidity was mostly between 20% and 60% in Ipseok-dae and was between 20 and 70% in Jigong Neodeol. Both areas had low wind speeds, with maxima of 5 m/s in Ipseok-dae and 3 m/s in Jigong Neodeol. As a result, it is evaluated that crack behavior in Ipseok-dae columnar joints and Jigong Neodeol rock blocks have maintained a very stable state so far. The surface temperature, temperature, relative humidity, and wind velocity of the two areas showed small difference depending on the season, indicating that they were affected to some extent by the season. From a long-term perspective, this can continuously affect the deformation of the Ipseok-dae columnar joints or Jigong Neodeol rock blocks. Therefore, in order to accurately evaluate their stability, it is considered that the current microscopic delamination and exfoliation or the propagation and expansion of cracks should be continuously measured.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.427-432
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• 2006

The possibility of citron seed oil for use as food resources of fats was tested by analyzing the composition of fatty acid and oxidative stability. Oil yield from citron seed was 55.4% in without roasting and 56.8% with roasting. Total mineral content in citron seed without and with roasting were 2,820.33 mg/kg, 1,702.55 mg/kg, respectively. For all citron seed oils tested, the potassium content was found to be the highest among four kinds of minerals detected in this study. Further, major fatty acids detected in the citron seed oils were linoleic acid, oleic acid and palmitic acid. Their relative contents with respect to total fatty acid contents were 77.12% in without roasting and 67.67% in with roasting. This result indicated that roasting the citron seed decreased the acid contents. However, POV (peroxide value) and acid value of citron seed oils were in,.eased significantly with increasing the storage days and heating time. In details, POV was $84.17{\pm}1.68meq/kg$ in without roasting and $76.46{\pm}1.19meq/kg$ with roasting, after 28 days. Acid value was $9.52{\pm}0.27mg\;KOH/g,\;8.35{\pm}0.09mg\;KOH/g$, respectively, After the 48 hours heating at $180^{\circ}C$, POV of citron seed oils was increased by 3.8 times, irrespective of roasting. Yet, acid value increased dramatically 8.3 in without and 6.4 times with roasting, exhibiting its dependence on roasting. During storage time, oxidative stability of citron seed oils was higher than heating.

• Journal of Conservation Science
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• v.33 no.6
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• pp.399-416
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• 2017

The 'Wat Phou and Associated Ancient Settlements within the Champasak Cultural Landscape' of Laos was designated as a UNESCO World Cultural Heritage in 2001. The uppermost structure of the Sanctuary in Wat Phou has been destroyed and being variably damaged, maintenance is required through scientific and systematic diagnosis. The Sanctuary of Wat Phou was constructed mainly using sandstones and bricks. There are physical damages including fracture, break out, exfoliation and interval as well as biological damages by lichen, mosses and weeds. According to the ultrasonic velocity measurement and property evaluation of the sandstones of the Sanctuary in Wat Phou, weathering index of the eastern side sandstones is 0.10 to 0.74 (mean 0.36), showing MW grade. Southern and northern side sandstones have relatively higher properties with average weathering indices of 0.30 and 0.32. The results of slope analysis of the Sanctuary, indicated that the 4th spot in the southern side has the largest slope of $5^{\circ}W$, seemingly due to the unstable ground around the Sanctuary. Based on the relative level measurement and past drawings, the Sanctuary is verified to have been located on ground with a certain slope rather than flatland. The ground of the southern side is inclined $1.51^{\circ}$ more than that of the northern side, which will affect the structural stability of the temple. The interval width of the selected southern spot is the largest with an average width of 159.5 mm, and the largest width is 328.3 mm at the top, since the width increases above rather than below, seemingly due to the unequal subsidence of the ground. Constant maintenance for conservation is required for the structural stability of the Sanctuary in Wat Phou, which was partly collapsed and has also suffered physical damage.