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        검색결과 1,668

        1.
        2024.04 구독 인증기관·개인회원 무료
        As climate change and population growth raise the likelihood of natural disasters, it becomes crucial to comprehend and mitigate these risks in vital infrastructure systems, especially nuclear power plants (NPPs). This research addresses the necessity for evaluating multiple hazards by concentrating on slope failures triggered by earthquakes near NPPs over a timeframe extending up to a return period of 100,000 years. Utilizing a Geographical Information System (GIS) and Monte Carlo Simulation (MCS), the research conducts a comprehensive fragility assessment to predict failure probability under varying ground-shaking conditions. According to the Newmark displacement method, factors such as Peak Ground Acceleration (PGA), slope angle, soil properties, and saturation ratio play significant roles in determining slope safety outcomes. The investigation aims to enhance understanding seismic event repercussions on NPP-adjacent landscapes, providing insights into long-term dynamics and associated risks. Results indicate an increase in slope vulnerability with longer return periods, with distinct instances of slope failures at specific return periods. This analysis not only highlights immediate seismic impacts but also underscores the escalating risk of slope displacement across the extended return period scales, crucial for evaluating long-term stability and associated hazards near nuclear infrastructure.
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research focuses on teaching Arabic to Jewish students in Jerusalem, a city of significant cultural and religious importance for both Arabs and Jews, especially under the backdrop of the prolonged conflict between these communities. The study asserts that the political complexity inherent in this context gives rise to unique challenges in teaching Arabic in Jewish schools in Jerusalem, which is influenced by conflict and racism. These factors contribute to the formation of a psychological barrier within the Arabic educational process. The objective of the study is to provide a comprehensive overview of the status of Arabic teaching to Jews in Jerusalem, emphasizing the unique aspects of this case and addressing the challenges encountered in the process. The outcomes of this research showed that the demographic composition of Jerusalem, with concentrations of both Arabs and extremist Jews, contributes to the distinctive nature of this case compared to other Israeli-occupied cities. This demographic factor influences the goals of teaching Arabic to Jews in Jerusalem and, concurrently, intensifies the challenges faced in this educational process, setting it apart from similar endeavors in different locations.
        6,400원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present research focuses on the tribological behavior of the AA5083 alloy-based hybrid surface composite using aluminosilicate and multi-walled-carbon nanotube through friction stir processing for automotive applications. The friction stir processing parameters (tool rotation and traverse speed) are varied based on full factorial design to understand their influence on the tribological characteristics of the developed hybrid composite. The surface morphology and composition of the worn hybrid composite are examined using a field-emission scanning electron microscope and an energy-dispersive x-ray spectroscope. No synergistic interaction is observed between the wear rate and friction coefficient of the hybrid composite plate. Also, adhesive wear is the major wear mechanism in both base material and hybrid composite. The influence of friction stir process parameters on wear rate and the friction coefficient is analyzed using the hybrid polynomial and multi-quadratic radial basis function. The models are utilized to optimize the friction stir processing parameters for reducing the rate of wear and friction coefficient using multi-quadratic RBF algorithm optimization.
        4,800원
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nanostructured dysprosium oxide ( Dy2O3) was synthesized by the co-precipitation method and incorporated with graphitic carbon nitride (g-C3N4) using the ultrasonication method. The resultant product is denoted as Dy2O3/ g-C3N4 nanocomposite which was further used for electrochemical sensing of riboflavin (RF). The physicochemical properties of Dy2O3/ g-C3N4 nanocomposite were examined using several characterization techniques. The obtained results exhibit the nanocomposite formation with the preferred elemental compositions, functional groups, crystalline phase and desired surface morphology. The electrocatalytic performance of Dy2O3/ g-C3N4 nanocomposite was scrutinized with a glassy carbon electrode (GCE) via differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques with the conventional three-electrode system. The modified electrode distributes more active surface area suggesting high electrocatalytic activity for the RF detection with two linear ranges (0.001–40 μM and 40–150 μM), a low detection limit of 48 nM and sound sensitivity (2.5261 μA μM−1 cm− 2). Further, the designed sensor possesses high selectivity, excellent stability, repeatability and reproducibility. Finally, the fabricated sensor was successfully estimated for the detection of RF in actual food sample analysis using honey and milk with better recovery.
        5,200원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, in order to increase the oxidation resistance of graphite, kaolin and alumina powder with different ratios (26A-74S, 49A-51S, 72A-28S) and slurry method were used to create an aluminosilicate coating on the graphite substrate. In order to reduce the difference in the coefficients of thermal expansion of graphite with aluminosilicate coating, aluminum metaphosphate coating as an interlayer was prepared on the surface of graphite by cathodic electrochemical treatment. The isothermal oxidation test of the samples was carried out in air at a temperature of 1250 °C for 1, 3 and 5 h. The microstructure, chemical composition, and phase components of the coating were, respectively, analyzed by scanning electron microscope equipped with an energy-dispersive spectrometer and X-ray diffraction. The results indicated that, by increasing the withdrawal speed of the samples in slurry method, the amount of changes in the weight of the samples has increased and therefore had a direct effect on oxidation. In addition, it was approved that, at high-temperature oxidation, AlPO4 glass phase forms on aluminum metaphosphate interlayer which retards graphite oxidation. Along with aluminum metaphosphate, aluminosilicate coating also produces a glass phase which fills and seals the voids on the surface which prevents the oxygen to reach the surface of graphite. The created double-layer coating including an interlayer of aluminum metaphosphate + slurry coating prepared with the ratio of 26A-74S as the optimal coating in this research was able to increase the oxidation resistance of graphite by 73% at a temperature of 1250 °C.
        4,600원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The widespread and extensive use of glyphosate in agriculture has raised concerns about its potential impact on the quality and safety of agricultural products. Conventional detection methods require long analysis times, making them impractical for the rapid detection of large quantities of samples. Therefore, developing a fast and simple detection system for glyphosate pesticide residues is urgent. In this study, the development of a facile fluorescence probe synthesized using a simple one-pot hydrothermal method for the determination of glyphosate is an important step toward addressing the need for a fast and simple detection system. The present sensor was created using bovine serum albumin (BSA) as a precursor, and the sensor operates by producing an “off–on” fluorescent signal. The bovine albumin-derived BSA-CDs emitted light yellow fluorescence, but this fluorescence was quenched (or suppressed) by the presence of Cu2+ ions. However, the fluorescence can be restored by the presence of glyphosate, which interacts with the Cu2+ ions to form a complex and release the BSACDs from suppression. The functional groups in glyphosate can capture Cu2+ and break the BSA-CDs/Cu2+ combinatorial system. The BSA-CDs/Cu2+ fluorescence quenching system had good selectivity for glyphosate. The detection limit of the BSA-CD/Cu2+ fluorescence sensor was 0.05 μg/mL. This developed method was utilized to successfully detect glyphosate in Chinese wheat. The average recoveries ranged from 98.9 to 100.7%, with a relative standard deviation < 3.0%, showing good prospects for practical applicability.
        4,200원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Reproductive management practices play crucial roles to maximize the reproductive performance of cows, and thus contribute to farm profitability. We aimed to assess the reproductive management of cows currently practiced in the dairy farms in an urban farming system. Methods: A total of 62 dairy farms were randomly selected considering all size of farms such as small (1-5 cattle), medium (6-20 cattle) and large farms (> 20 cattle) from selected areas of Dhaka city in Bangladesh. The reproductive managementrelated parameters viz. estrus detection, breeding method, pregnancy diagnosis, dry cow and parturition management, vaccination and treatment of reproductive problems etc. were obtained in a pre-defined questionnaire during the farm visit. Results: The visual observation method was only used (100.0%; 62/62) for estrus detection irrespective of size of the farms; while farmers observed cows for estrus 4-5 times a day, but only for 20-60 seconds each time. Regardless of farm size, 89.0% (55/62) farms used artificial insemination (AI) for breeding the cows. Intriguingly, all farms (100.0%) routinely checked the cows for pregnancy at 35-40 days post-breeding using rectal palpation technique by registered veterinarian. However, only 6.5% (4/62) farms practiced dry cow management. Notably, all farms (100.0%) provided nutritional supplements (Vit D, Ca and P) during late gestation. However, proper hygiene and cleanliness during parturition was not practiced in 77.4% (48/62) farms; even though 96.7% (60/62) farms treated cows by registered veterinarian for parturition-related problems. Conclusions: While farmers used AI service for breeding and timely check their cows for pregnancy; however, they need to increase observation time (30 minutes/ observation, twice in a day: early morning and early night) for estrus detection, consider dry cow management and ensure hygienic parturition for maximizing production.
        4,000원
        10.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flexible supercapacitors (FS) are ideal as power backups for upcoming stretchable electronics due to their high power density and good mechanical compliance. However, lacking technology for FS mass manufacturing is still a significant obstacle. The present study describes a novel method for preparing FS based on reduced graphene oxide (RGO) using the N+ plasma technique, in which N+ reduces graphene oxide on the surface of a cotton/polyester substrate. The effect of aloe vera (AV) as a natural reducing & capping agent and carbon nanotubes (CNT) as nanoconductors on the electrochemical performance of the electrodes is studied. FESEM and XPS were employed to investigate the electrodes' structural and chemical composition of electrodes. The galvanostatic charge–discharge curves of electrodes revealed the enhancement of the electrochemical activity of the as-prepared electrode upon additions of AV and CNT. The areal capacitance of the RGO, RGO/AV, and RGO/ AV/CNT supercapacitors at 5 mV/s was 511, 1244.5, and 1879 mF/cm2, respectively. The RGO electrode showed capacitive retention of 80.9% after 2000 cycles enhanced to 89.7% and 92% for RGO/AV and RGO/AV/CNT electrodes, respectively. The equivalent series resistance of the RGO electrode was 126.28 Ω, decreased to 56.62 and 40.06 Ω for RGO/AV and RGO/ AV/CNT electrodes, respectively.
        4,000원
        18.
        2023.10 구독 인증기관·개인회원 무료
        19.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Evaluating the effectiveness of the radiation protection measures deployed at the Centralized Radioactive Waste Management Facility in Ghana is pivotal to guaranteeing the safety of personnel, public and the environment, thus the need for this study. RadiagemTM 2000 was used in measuring the dose rate of the facility whilst the personal radiation exposure of the personnel from 2011 to 2022 was measured from the thermoluminescent dosimeter badges using Harshaw 6600 Plus Automated TLD Reader. The decay store containing scrap metals from dismantled disused sealed radioactive sources (DSRS), and low-level wastes measured the highest dose rate of 1.06 ± 0.92 μSv·h−1. The range of the mean annual average personnel dose equivalent is 0.41–2.07 mSv. The annual effective doses are below the ICRP limit of 20 mSv. From the multivariate principal component analysis biplot, all the personal dose equivalent formed a cluster, and the cluster is mostly influenced by the radiological data from the outer wall surface of the facility where no DSRS are stored. The personal dose equivalents are not primarily due to the radiation exposures of staff during operations with DSRS at the facility but can be attributed to environmental radiation, thus the current radiation protection measures at the Facility can be deemed as effective.
        4,200원
        20.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Structural inversion refers to the reverse reactivation of extensional faults that influence basin shortening accommodated by contractional faults or folds. On the Korean peninsula, Miocene inversion structures have been found, but the Cretaceous rocks on Geoje Island may have undergone inversion as early as the Upper Cretaceous. To evaluate the structural inversion on Geoje Island, located on the eastern side of South Korea, and to determine the effects of preexisting weakness zones, field-based geometric and kinematic analyses of faults were performed. The lithology of Geoje Island is dominated by hornfelsified shale, siltstone, and sandstone in the Upper-Cretaceous Seongpori formation. NE and NW-oblique normal faults, conjugate strike-slip (NW-sinistral transpressional and E-W-dextral transtensional) faults, and NE-dextral transpressional faults are the most prominent structural features in Geoje Island. Structural inversion on Geoje Island was evidenced by the sinistral and dextral transpressional reactivation of the NW and NE-trending oblique normal faults respectively, under WNW-ESE/NW-SE compression, which was the orientation of the compressive stress during the Late Cretaceous to Early Cenozoic.
        4,900원
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