Mild cognitive impairment (MCI) is a precursor to dementia and its early diagnosis in patients is important for appropriate intervention. In this study, an IoT (Internet of Things) device is ...developed that easily and conveniently screens for MCI, provides emotional comfort for elderly patients, and has a friendly design. It enables us to screen MCI by efficiently identifying the user's condition in non-face-to-face manner. The experimental result and survey of this study show that this device will establish itself as a distinguished companion doll that can be widely shared with the elderly.
Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe-Al-Mn-C alloys were patented in 1950s for replacement of nickel or chromium in ...corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest.
It has recently been suggested that the extraordinary strain hardening rate in Fe-16Mn-10Al-0.86C-5Ni high specific strength steel 1 is due to the high back stresses arising from the strain ...incompatibility between austenite matrix and B2-ordered intermetallic second phase 2. I argue here that the alloy matrix chemistry, particularly short-range ordering of constituent atoms, could be the intrinsic factor that affects the deformation and strain hardening, rather than the stress-strain partitioning caused by the microstructural heterogeneity.
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The Korea Oceanographic Data Center (KODC), overseen by the National Institute of Fisheries Science (NIFS), is a pivotal hub for collecting, processing, and disseminating marine science data. By ...digitizing and subjecting observational data to rigorous quality control, the KODC ensures accurate information in line with international standards. The center actively engages in global partnerships and fosters marine data exchange. A wide array of marine information is provided through the KODC website, including observational metadata, coastal oceanographic data, real-time buoy records, and fishery environmental data. Coastal oceanographic observational data from 207 stations across various sea regions have been collected biannually since 1961. This dataset covers 14 standard water depths; includes essential parameters, such as temperature, salinity, nutrients, and pH; serves as the foundation for news, reports, and analyses by the NIFS; and is widely employed to study seasonal and regional marine variations, with researchers supplementing the limited data for comprehensive insights. The dataset offers information for each water depth at a 1 m interval over 1980–2022, facilitating research across disciplines. Data processing, including interpolation and quality control, is based on MATLAB. These data are classified by region and accessible online; hence, researchers can easily explore spatiotemporal trends in marine environments.
Energy consumption in the industrial sector can be significantly reduced by improving heat transfer rates in heat exchanger circuits, pool boiling, metal cutting industries, etc. Numerous ...energy-related issues can be overcome to a large extent by improving heat flow properties by utilizing nanofluids. The present contribution reviews the improvement in thermophysical properties of metal oxide-based nanofluids. Key parameters affecting the thermophysical properties of nanofluids, such as particle volume fraction, temperature, particle size and various stabilizers, were reviewed. The importance of DLVO theory and zeta potential to control the electrostatic repulsion and pH values of nanofluids for stable nanofluid formulations were discussed. It has been observed that classical theories of thermal conductivity and viscosity cannot predict exact values for a wide range of variables. Therefore, various extensive correlations have been introduced to predict the thermophysical properties of nanofluids. In these correlations, individual dependent variables such as particle size, temperature, nanofluid layer thickness, and Brownian velocity of nanoparticles, etc. were considered for more accurate prediction. The heat transfer efficiencies of nanofluids to base fluids in the laminar and turbulent regimes have been discussed using various figures of merits. Finally, the scope of industrial applications of metal oxide-based nanofluids and future research opportunities have been discussed.
Aluminum and silicon are common alloying elements for tuning the stacking fault energy (SFE) of high Mn steels. Today the theoretical investigations on the Fe-Mn-Al/Si systems using Density ...Functional Theory (DFT) are very scarce. In the present study, we employ a state-of-the-art longitudinal spin fluctuations (LSFs) model in combination with DFT for describing the magnetic effects in Fe-Mn based alloys at finite temperature. We find that the traditional DFT-floating spin results fail to explain the experimental trends. However, the DFT-LSFs approach properly captures the Al-induced increase and Si-induced decrease of the SFE of the base alloy in line with the room-temperature observations. This finding highlights the importance of LSFs in describing the Al/Si effects on the SFE of Fe-Mn based alloys. We point out that the effects of the non-magnetic Al and Si additions on the SFE are in fact determined by the magnetic state of the host matrix. In addition, we estimate the role of carbon addition in the alloying effects of Al and Si. The present results provide a convenient pathway to access the important mechanical parameters for designing advanced high-strength alloys.
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•Traditional floating spin models fail to account for the experimental trends.•Longitudinal spin fluctuations yield stacking fault energies in good agreement with experiments.•The magnetic state of the host Fe-Mn alloy is determinative for the alloying trends on the stacking fault energy.
The Yellow Sea Bottom Cold Water (YSBCW) refers to seawater with a water temperature of 10 °C or less found at the bottom of the center of the Yellow Sea. The spatiotemporal variability of the YSBCW ...directly affects the distribution of organisms in the marine ecosystem. In this study, hydroacoustic and net surveys were conducted in April (spring) to understand the spatial distribution of the sound scattering layer (SSL) and estimate the density of Euphausia pacifica (E. pacifica) in the YSBCW. Despite the shallow water in the YSBCW region, E. pacifica formed an SSL, which was distributed near the bottom during the daytime; it showed a diel vertical migration (DVM) pattern of movement toward the surface during the nighttime. The mean upward and downward swimming speeds around sunset and sunrise were approximately 0.6 and 0.3–0.4 m/min, respectively. The E. pacifica density was estimated in the central, western, and eastern regions; the results were approximately 15.8, 1.3, and 10.3 g/m2, respectively, indicating significant differences according to region. The results revealed high-density distributions in the central and eastern regions related to the water temperature structure, which differs regionally in the YSBCW area. Additional studies are needed regarding the spatial distribution of E. pacifica in the YSBCW and its relationship with various ocean environmental parameters according to season. The results of this study contribute to a greater understanding of the structure of the marine ecosystem in the YSBCW.
Japanese anchovy (Engraulis japonicus) is an economically important species found in the coastal waters of the northwestern Pacific Ocean. To conduct effective acoustic surveys on the spawning or ...fishing grounds of this species, the target strength (TS, dB re 1 m2) during its growth stages must be understood. However, knowledge regarding the TS of juvenile Japanese anchovies is limited. To address this knowledge gap, we measured the TS and proposed equation models for juvenile Japanese anchovies while describing the TS differences between young and adult anchovies. We evaluated 21 live anchovies using 38, 120, and 200 kHz transducers. TS models were fitted for the juvenile stage of anchovies, considering different frequencies. The mean TS values of young and adult anchovies were similar to those reported in previous TS studies, whereas the TS values of juvenile anchovies were significantly lower. Thus, applying the same TS equation based on the acoustic characteristics of anchovies at different growth stages, especially for juvenile anchovies, may not be appropriate. These findings underscore the importance of adopting a suitable TS equation specific to the growth stages of Japanese anchovies for accurate data analysis in acoustic surveys conducted on spawning and fishing grounds.
Aluminum monoxide (AlO) and a nonstoichiometric alumina (n-alumina) with its chemical composition similar to that of AlO were proposed theoretically for a promising low-loss plasmonic material. ...However, they were rarely studied due to the high thermodynamic instability. Recently, n-aluminas with their O/Al atomic ratios close to 1 were found to form on Al nanospheres synthesized by electrical explosion. Although a new bulk plasmon resonance was observed below the excitonic transition energy from the n-aluminas, no investigation into surface plasmon resonance – the key component for plasmonics - was conducted yet. Here I report on surface plasmons of the n-aluminas discovered by spatially-resolved electron energy loss spectroscopy. Energy loss spectra collected from local spots of the n-aluminas are analyzed to reveal that there are two types of n-aluminas; one with two surface plasmons (n-alumina A) and the other with one surface plasmon (n-alumina B). Remarkably, the oscillator strengths of the novel surface plasmons are as high as that of surface plasmon of Al. The electronic band structure proposed for the n-alumina A shows a lossless energy zone. Consequently, current study demonstrates that the n-aluminas have the potential as a new low-loss plasmonic material.
•Nonstoichiometric alumina (n-alumina) is studied for a new plasmonic material.•The n-alumina can have one or two novel surface plasmon resonances.•The oscillator strengths of the novel surface plasmons are very high.•The n-alumina shows only a small amount of damping at optical frequencies.•The n-alumina may have the desirable zero-loss zone in the energy band structure.
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