• 한국노년학
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• v.30 no.4
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• pp.1345-1357
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• 2010

This research, with the participants of the female elderly using a home-visit bath among long-term care services, made an in-depth analysis of what they experience while getting a home-visit bath. We conducted in-depth interviews with 8 elderly people. According to the result, the female elderly experienced the absence of a caregiver, difficulty in carrying out daily life due to physical diseases, getting what they need by themselves, getting comfortable in body and mind, accepting their given situation though feeling shame at getting a bath, and expressing their desires. In addition, they had a close relationship with a care helper. On the basis of the results, a systematic training system which could intensify the professionalism of care helpers was suggested. For the enhancement of the elderly's emotional stability in a long-term care, an integrated case management system was also suggested, which supports the family by organizing an integrated network by region between a long-term care service, home-visit care service, welfare center, and the National Health Insurance Corporation.

• The Journal of Advanced Prosthodontics
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• v.15 no.5
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• pp.227-237
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• 2023

PURPOSE. This study aimed to assess and compare the color stability, flexural strength (FS), and surface roughness of occlusal splints fabricated from heat-cured acrylic resin, milled polymethyl methacrylate (PMMA)-based resin, and 3D-printed (PMMA) based-resin. MATERIALS AND METHODS. Samples of each type of resin were obtained, and baseline measurements of color and surface roughness were recorded. The specimens were divided into three groups (n = 10) and subjected to distinct aging protocols: thermomechanical cycling (TMC), simulated brushing (SB), and control (without aging). Final assessments of color and surface roughness and three-point bending test (ODM100; Odeme) were conducted, and data were statistically analyzed (2-way ANOVA, Tukey, P <.05). RESULTS. Across all resin types, the most significant increase in surface roughness (Ra) was observed after TMC (P < .05), with the 3D-printed resin exhibiting the lowest Ra (P < .05). After brushing, milled resin displayed the highest Ra (P < .05) and greater color alteration (∆E₀₀) compared to 3D-printed resin. The most substantial ∆E₀₀ was recorded after brushing for all resins, except for heat-cured resin subjected to TMC. Regardless of aging, milled resin exhibited the highest FS (P < .05), except when compared to 3D-printed resin subjected to TMC. Heat-cured resin exposed to TMC demonstrated the lowest FS, different (P < .05) from the control. Under control conditions, milled resin exhibited the highest FS, different (P < .05) from the brushed group. 3D-printed resin subjected to TMC displayed the highest FS (P < .05). CONCLUSION. Among the tested resins, 3D-printed resin demonstrated superior longevity, characterized by minimal surface roughness and color alterations. Aging had a negligible impact on its mechanical properties.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.169-185
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• 2023

The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.

• KIPS Transactions on Computer and Communication Systems
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• v.13 no.1
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• pp.21-30
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• 2024

As the self-driving car market continues to grow, the need for charging infrastructure is growing. However, in the case of a wireless charging system, stability issues are being raised because it requires a large amount of power compared with conventional wired charging. SAE J2954 is a standard for building autonomous vehicle wireless charging infrastructure, and the standard defines a communication method between a vehicle and a power transmission system. SAE J2954 recommends using physical media such as Wi-Fi, Bluetooth, and UWB as a wireless charging communication method for autonomous vehicles to enable communication between the vehicle and the charging pad. In particular, UWB is a suitable solution for indoor and outdoor charging environments because it exhibits robust communication capabilities in indoor environments and is not sensitive to interference. In this standard, the process for building a wireless power transmission system is divided into several stages from the start to the completion of charging. In this study, UWB technology is used as a means of fine alignment, a process in the wireless power transmission system. To determine the applicability to an actual autonomous vehicle wireless power transmission system, experiments were conducted based on distance, and the distance information was collected from UWB. To improve the accuracy of the distance data obtained from UWB, we propose a Single Model and Multi Model that apply machine learning and deep learning techniques to the collected data through a three-step preprocessing process.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.4
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• pp.203-214
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• 2023

In this study, the physical properties and fracture characteristics according to the tensile load are evaluated on the materials of the polymeric filler and carbon fiber-based composite sleeve technique. The polymeric filler and the composite sleeve technique are applied to areas where the pipe body thickness is reduced due to corrosion in large-diameter water pipes. First, the tensile strength of the polymeric filler was 161.48~240.43 kg_f/cm², and the tensile strength of the polyurea polymeric filler was relatively higher than that of the epoxy. However, the tensile strength of the polymeric filler is relatively very low compared to ductile cast iron pipes(4,300 kg_f/cm²<) or steel pipes(4,100 kg_f/cm²). Second, the tensile strength of glass fiber, which is mainly used in composite sleeves, is 3,887.0 kg_f/cm², and that of carbon fiber is up to 5,922.5 kg_f/cm². The tensile strengths of glass and carbon fiber are higher than ductile cast iron pipe or steel pipe. Third, when reinforcing the hemispherical simulated corrosion shape of the ductile cast iron pipe and the steel pipe with a polymeric filler, there was an effect of increasing the ultimate tensile load by 1.04 to 1.06 times, but the ultimate load was 37.7 to 53.7% compared to the ductile cast iron or steel specimen without corrosion damage. It was found that the effect on the reinforcement of the corrosion damaged part was insignificant. Fourth, the composite sleeve using carbon fiber showed an ultimate load of 1.10(0.61T, 1,821.0 kg_f) and 1.02(0.60T, 2,290.7 kg_f) times higher than the ductile cast iron pipe(1,657.83 kg_f) and steel pipe(2,236.8 kg_f), respectively. When using a composite sleeve such as fiber, the corrosion damage part of large-diameter water pipes can be reinforced with same level as the original pipe, and the supply stability can be secured through accident prevention.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.194-199
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• 2024

Accidents due to aircraft fuel defects rank in the top 13 of the 34 accident types described by CAST-ICAO Common Taxonomy Team(CICTT). Aircraft accidents occur because of the inflow of moisture or pollutants depending on the distribution process and storage environment. To confirm the change in physical properties of the aircraft oil stored for a long time, we stored JET A-1 aircraft oil in a metal can to observe the change after six months. We confirmed that the aircraft oil stored for a long time satisfied the quality standards, and the stability of the fuel oil was high. However, in scenarios in which aircraft oil is stored separately on ships, onshore storage facilities, oil fields, etc., owing to the nature of missions, such as in marine police aircraft, the inflow of moisture or pollutants may likely occur due to changes in the internal and external environment. In addition, pollutants can be analyzed using existing tests and distillation properties, but for moisture, domestic and international standards and domestic laws determine the moisture separation ability of aircraft oil through the water separation index, but the moisture content is not analyzed. Therefore, aviation safety must be secured by adding quality control standards for moisture content and performing revisions to uniformize domestic and international standards and laws.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.262-268
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• 2024

In this study, the MXene/Si composite was prepared by electrostacic assembly with 2-dimensional structured titanium carbide (MXene) and nano silicon for anode material of high-performance lithium-ion battery. Ti₃C₂T_x MXene was synthesized by etching the Ti₃AlC₂ MAX with LiF/HCl, and the surface of nano silicon was charged to positively using CTAB (Cetyltrimethylammonium bromide). The MXene/Si anode composite was successfully manufactured by simple mixing process of synthesized MXene and charged silicon. The physical and electrochemical properties of prepared composite were investigated with MXene-silicon composition ratio, and the surface of electrode after cycles was analyzed to evaluate stability of the electrode. The MXene/Si composites demonstrated high initial discharge capacities of 1962.9, 2395.2 and 2504.3 mAh/g as the silicon composition ratio increased to 2, 3 and 4 compared to MXene, respectively. MXene/Si-4, which is MXene and silicon ratio with 1 : 4, exhibited 1387.5 mAh/g of reversible capacity, 74.5% of capacity retention at 100 cycles and high capacity of 700.5 mAh/g at high rate of 4.0 C. As the results, the MXene/Si composite prepared by electrostatic-assenbly could be applied to anode materials for high-performance LIBs.

• Journal of Music and Human Behavior
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• v.21 no.2
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• pp.135-157
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• 2024

In this study, the authors developed and implemented an online music-based support program to prevent burnout among university hospital nurses. This study involved 40 nurses from three university hospitals who shared their subjective experiences after participating in 8 music-based non-simultaneous online sessions. The responses were collected as qualitative data and analyzed using the qualitative content analysis method. The analysis identified 66 meaning units, 10 themes, and 3 categories, which included: 'Recovery of physical and psychological stability', 'Self-care and acceptance', and 'Rediscovery of pride and meaning as a nurse'. This study is significant for exploring the experiences of university hospital nurses who participated in a remotely implemented music-based psycho-emotional support program, with respect to burnout prevention. For future directions, we suggest a more in-depth exploration of specific burnout factors and an expansion of research through the diversification of research methods to refine programs aimed at alleviating nurse burnout.

• Journal of the Korean Wood Science and Technology
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• v.52 no.5
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• pp.423-437
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• 2024

Wood biomass, such as sawdust, particles, and chips from the wood industry, can be potentially used as a composite product. Chip block pallets (CBP) are composite products that can be produced from industrial wood waste and are in high demand in the logistics sector. Therefore, this study aimed to investigate the production of CBP from teak wood biomass with varying polyurethane contents. In addition, this study analyzed the optimum particle-size composition was determined. The CBP production of CBP be divided into two stages. The first stage evaluated the use of polyurethane adhesive content, whereas the second stage considered the effect of particle size composition. The 9 × 9 × 9 cm³ of CBP with 0.6 g/cm³ target density was fabricated using a cold press. The National Wooden Pallet and Container Association (NWPCA) standards were used to evaluate the density, moisture content, dimensional stability, water absorption, compressive strength (CS), and screw-holding strength (SHS) of our CBP products. The mechanical and physical properties of CBP products were investigated. As a result, the CBP sample prepared using 4-14 mesh particle size and 4.5% adhesive content showed the optimal strength values, such as CS of 14.67 MPa and SHS of 371.50 N. These findings demonstrate that the CBPs derived from teak wood waste closely resemble commercial chip blocks and have the potential to replace wood bearings as pallet pads.

• The Journal of Sustainable Design and Educational Environment Research
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• v.23 no.3
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• pp.1-13
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• 2024

This study aims to identify users' perceptions and needs to improve college teaching spaces in nursing education, and thus derive improvement measures. Therefore, group interviews (three to five participants per category) were conducted with professors (7), students (9), and administrative staff (8) at a college of nursing located in Seoul. All interviews were conducted face-to-face, with each interview taking approximately 60-90 min. The interview results were analyzed for professors, students, and administrative staff separately. The following implications were drawn by synthesizing the interview results for each group: (1) the physical environment and quality of interaction between professors and students need to be improved in order to enhance the quality of teaching and learning; (2) a well-designed practice environment that allows students to practice various skills with confidence needs to be provided; (3) classrooms need to be configured and arranged in a way that is appropriate the nursing curriculum and educational activities to maximize learning effectiveness; (4) spatial restructuring is necessary in terms of living and resting spaces to help nursing students manage stress and provide them with psychological stability; and (5) administrative support reflecting the nursing curriculum is needed in establishing classroom assignment criteria and space use regulations. Finally, the limitations of this study and suggestions for further research were discussed.