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This study examined the effects of group composition based on the learners' personality types as measured by the Myers-Briggs type indicator as they interacted in threaded discussions. Three groups comprised introverts, extroverts, and mixed introvert-extrovert classifications. Ninety-six participants were divided into 24 groups of 4 participants each: 8 introverted, 8 extroverted, and 8 mixed. Dependent measures included number of posted messages, social, interactive, cognitive, and metacognitive interaction as measured by Henri's (1992) scheme for coding the type of interaction. Participants in the mixed and extroverted groups posted more messages than those in the introverted group. The extroverted and mixed groups' learners showed more social, interactive, and cognitive interaction than those of the introverted group. However, the mixed group showed more metacognitive interaction than that of the extroverted group. (Contains 2 tables.)

[Display omitted] The Sudokwon landfill (SL) in the Seoul metropolitan area, South Korea, is among the world's largest landfills, striving to curtail landfill gas (LFG) emissions and achieve carbon neutrality by 2050. Since 2005, the SL Management Corporation (SLC) has measured LFG emissions (i.e., methane (CH 4) and carbon dioxide (CO 2)) using a dynamic flux chamber proposed by the US EPA. However, uncertainty prevails in validating the reduction of LFG emissions due to the limited spatiotemporal data coverage. In 2020, an eddy covariance (EC) system was installed to enhance measurements, revealing highly fluctuating LFG emissions driven by waste layer LFG production, LFG collection, and atmospheric pressure changes. During the study period, the annual CH 4 emission increased slightly from 465.0 ± 4.2 to 485.5 ± 6.4 g C m−2, while that of CO 2 decreased by 2/3 (from 408.7 ± 16.5 to 270.6 ± 18.8 g C m−2), primarily due to the doubled CO 2 uptake by the vegetated topsoil. Our first long-term (March 2020 to February 2022) quasi-continuous monitoring using EC (with a gap-filling and partitioning technique based on Random Forest) emphasizes the difficulty of temporal upscaling of discontinuously observed surface emissions to quantify the LFG inventory and the need for continuous observations or suitable proxies (e.g., atmospheric CH 4 concentration). [ABSTRACT FROM AUTHOR]

Background: The identification of predictors for body image distortion would be an especially important first step in targeting a vulnerable population and developing a nutrition intervention program. We aimed to investigate the prevalence of body image distortion and the factors associated with body image distortion among Korean high school students.Methods: We selected 20,264 normal weight high school students from the 10(th) Korea Youth Risk Behavior Web-based Survey using nationally representative data in 2014. With multivariate logistic regression, we assessed the association of body image distortion with individual demographic and socio-economic factors, weight control behaviors, and mental health characteristics.Results: The over-estimation group of body weight status, compared with the correct estimation group, was significantly more likely to be a 3(rd) year high school student [adjusted odds ratio (AOR): 1.27, 95% confidence interval (CI): 1.16-1.39], to be female [AOR: 3.52, 95% CI: 3.25-3.81], to employ unhealthy weight control behaviors [AOR: 1.54, 95% CI: 1.37-1.72], and to have a sadness [AOR: 1.25, 95% CI: 1.16-1.35] and suicidal ideation [AOR: 1.20, 95% CI: 1.08-1.33]. The under-estimation group, compared with the correct estimation group, was significantly less likely to be female [AOR: 0.23, 95% CI: 0.21-0.25] and to employ unhealthy weight control behaviors [AOR: 0.50, 95% CI: 0.43-0.59] but were more likely to have a sadness [AOR: 1.12, 95% CI: 1.03-1.21] and suicidal ideation [AOR: 1.12, 95% CI: 1.00-1.25].Conclusions: Not only the over-estimation but also the under-estimation of body weight is prevalent among high school students in South Korea. Body image distortion was significantly associated with sadness and suicidal ideation. [ABSTRACT FROM AUTHOR]

To evaluate long-term temperature changes caused by the operation of a geothermal heat pump (GHP) system, temperatures near borehole heat exchangers (BHEs) of the GHP system in Korea were measured. The temperature measurements showed increasing rates of 0.135 °C/year at a depth of 10 m and 0.118 °C/year at a depth of 50 m for approximately 10 years. Simulations for the analysis of climate change effects on measured temperature fluctuations showed that a rate of temperature increase was 0.010 °C/year at a depth of 50 m owing to changes in surface air temperatures (SATs). From two-dimensional heat transfer simulations, the discharged heat measuring 16.7 W/m in the cooling season and extracted heat measuring 12.4 W/m in the heating season could cause an annual mean temperature increase of 0.109 °C over approximately 10 years. Additionally, results of simulations for future prediction of ground temperatures assuming that the GHP system retains its level of operation showed that in 2050, temperature at a depth of 50 m will increase by approximately 3.00 °C from that in 2005. Thus, balancing the heat discharged into and extracted from the ground by considering climate change to minimize long-term changes in the ground temperature is necessary. [ABSTRACT FROM AUTHOR]

• 3D grid-based screening process could be used to quickly screen different sub-basins or aquifers for CO 2 storage potential. • Instead of estimating the storage capacity, Gravitational Number is used as screening criterion. • The proposed criteria and ranking framework are applicable to identify suitable regions for the early CCS implementation. • The ranking results of six sub-basins in the Gunsan Basin indicate that the East Sub-basin is the most promising region. This study presents an approach to screen sedimentary basins for their CO 2 geological storage potential based on a 3D grid with geological data. The 3D grid-based screening was applied to the Gunsan Basin, offshore Korea, for selecting potential sub-basins. Six sub-basins were recognized and prioritized using a set of quantifiable criteria, reflecting storage capacity, geological risk, and socio-economic aspects. Nine criteria were defined and weighed to reflect local priority and geological characteristics. Every grid cell was populated with geological and geometrical properties, scored and ranked for each criterion. Typically, the storage capacity is used for evaluating the storage potential of a basin, which, however, was not estimated here due to the low quantity of available data. Instead, the capacity potential was quantified by combining the pore volume and Gravitational Number for each grid cell. Mean score values for each sub-basin indicate that the East Sub-basin is the most promising region, containing a suitable aquifer with an estimated storage capacity of a few hundreds of MtCO 2. Therefore, we suggest that the Gunsan Basin is suitable for implementing a CCS program with an injection rate of 4 MtCO 2 /year for 30 years. Moreover, we suggest that the 3D grid-based screening process could be used to quickly screen different sub-basins or potential aquifers by depth. [ABSTRACT FROM AUTHOR]

A lake is one of the geothermal energy sources to meet increasing demands for renewable energy use. In this study, a series of numerical modeling was performed to evaluate the applicability of a close-loop lake water heat pump (LWHP) system in Lake Soyang, Korea. A non-isothermal pipe flow model was used to simulate the flow and heat transfer processes occurring in the LWHP system with the main pipe and several helical tubes for heat exchange. Based on the temperature data measured in the Lake Soyang for 4 years, the installation depth and the number of helical tubes were determined sequentially, and the sensitivities of additional installation and operation factors on the system performance were analyzed. Assuming a mild current in the lake, the installation and operation conditions for the efficient operation of the system were suggested as follows: The installation of 16 helical tubes at 50 m deep, the circulation rates of heat-carrier fluid of 189.3 L/min, the inner diameter of tubes of 32 mm, and the wall thickness and thermal conductivity of 2.9 mm and 0.4 W/mK, respectively. Considering many lakes and reservoirs in Korea, the closed-loop LWHP system would be a viable renewable energy application. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper is to present and test a model of innovativeness improvement based on the impact of organizational learning culture. The concept of organizational learning culture (OLC) is presented and defined as a set of norms and values about the functioning of an organization. They should support systematic, in-depth approaches aimed at achieving higher-level organizational learning. The elements of an organizational learning process that we use are information acquisition, information interpretation, and behavioral and cognitive changes. Within the competing values framework OLC covers some aspects of all four different types of cultures: group, developmental, hierarchical, and rational. Constructs comprising innovativeness are innovative culture and innovations, which are made of technical (product and service) and administrative (process) innovations. We use data from 201 Korean companies employing more than 50 people. The impact of OLC on innovations empirically tested via structural equation modeling (SEM). The results show that OLC has a very strong positive direct effect on innovations as well as moderate positive indirect impact via innovative culture. [Copyright &y& Elsevier]

• Helium-cooled ceramic reflector (HCCR) blanket concept was proposed as a DEMO breeding blanket in Korea. • As a pre-conceptual design study, neutronic assessment of the HCCR blanket was carried out by inserting the newly developed model into the K-DEMO three-dimensional neutronic calculation model. • As results, the peak neutron wall load of 4.06 MW/m2 was obtained at the outboard midplane blanket first wall for the fusion power of 3 GW. The overall tritium breeding ratio (TBR) was estimated as 1.10. Helium-cooled ceramic reflector (HCCR) blanket concept was proposed as a DEMO breeding blanket in Korea. It adopted lithium ceramic breeder, graphite reflector to reduce the beryllium multiplier, reduced activation ferritic-martensitic steel as a structural material, and high pressure/temperature helium as a coolant. As a pre-conceptual design study, neutronic assessment of the HCCR blanket was carried out by inserting the newly developed model into the K-DEMO three-dimensional neutronic calculation model. As results, the peak neutron wall load of 4.06 MW/m2 was obtained at the outboard midplane blanket first wall for the fusion power of 3 GW. The overall tritium breeding ratio (TBR) was estimated as 1.10. And the poloidal mean global TBR distribution at the blankets were calculated. [ABSTRACT FROM AUTHOR]

• An experiment and Discrete Element Method (DEM) analysis was carried out to fill the interior space with pebbles. • Vibrating the container while filling the pebbles is more beneficial to increase the packing fraction and simplify the filling process than vibrating after filling. • As long as the gaps between the grooved tips are wide enough, there is no problem with the pebbles filling in between them, and there was no significant negative impact on packing fraction. To develop tritium breeding technology for fusion reactors, Korea actively participated in the ITER Test Blanket Module (TBM) program, focusing on the development of a ceramic breeder-type TBM. The challenge was to introduce pebbles into the TBM without causing any damage to them. This study conducted experiments and Discrete Element Method (DEM) analyses to optimize the pebble-filling process for breeding blanket development. Even when facing obstacles such as grooved shapes on the walls of the pebble-filled space, these grooves did not significantly reduce the packing ratio. Vibrating the pebbles proved essential to increase the pebble packing ratio. Both experiments and DEM analyses confirmed an increase in pebble packing when vibration is applied. The study also investigated the impact of the timing of vibration application. It is better to vibrate after the pebble injection is done during injection to increase the pebble packing ratio. This approach increases the pebble packing ratio, but it also makes additional empty space. Consequently, maintaining continuous vibration from the initiation to the completion of the injection process can increase the packing ratio without the need to repeat the injection process to fill the empty space. [ABSTRACT FROM AUTHOR]

• The first wall fabrication technologies of the HCCR blanket using laser beam welding (LBW) and hot isostatic pressure (HIP) bonding were developed. • The LBW conditions and procedures were optimized to remove the backing strip and achieve uniform and continuous back beads. • The partial HIP bonding line caused a slight decrease in the tensile strength, but the impact on the HCCR blanket design would be negligible. The helium-cooled ceramic reflector (HCCR) concept is a primary candidate among demonstration fusion power reactor (DEMO) blanket options in Korea. The HCCR blanket is composed of a first wall (FW), a breeding zone, side cover plates and a back manifold. This study focuses on fabrication technologies for the FW using laser-beam welding (LBW) and hot isostatic pressure (HIP) bonding. Permanent backing strips in the pressure boundaries of the HCCR blanket are not allowed according to regulations related to pressure vessels and nuclear pressure vessels because high-pressure helium gas at 8 MPa is used as the coolant. LBW conditions and procedures for the fabrication of a FW without backing strips were investigated using small mock-ups with an advanced reduced-activation alloy called ARAA, which was developed in Korea. The laser beam power, thickness of the cover plate, and width of the backing strips were considered as parameters. The LBW conditions and procedures were optimized to remove the backing strip and achieve uniform and continuous back beads. After LBW, the fabrication of the FW with small mock-ups was completed by joining the back plate with HIP bonding. The small mock-ups were subject to very high temperatures exceeding 1000°C during the LBW and HIP bonding processes, which led to changes in the microstructures and hardness levels. The microstructures and hardness levels were recovered through post-heat treatments performed after HIP bonding. The microstructures of the HIP bonding interface after the heat treatments were observed. A partial HIP bonding line was confirmed and transverse tensile tests were carried out to investigate the impact of the partial HIP bonding line on the mechanical properties of the HIP bonding interface. The tensile strength of the HIP bonding interface was approx. 2% lower than that of the base metal, indicating that the partial HIP bonding line caused a slight decrease in the tensile strength, but the impact on the HCCR blanket design would be negligible. [ABSTRACT FROM AUTHOR]

• The main functions and design concepts of the HCCR breeding blanket are to be verified in ITER through the HCCR Test Blanket Module (TBM) program. • R&D activities for the HCCR TBM program in the fields of structural and breeder material, TBM set fabrication technology, tritium extraction technology, and helium cooling technology were introduced. • The maximum operating temperature and pressure conditions and thermal properties of Li 2 TiO 3 were determined by investigating the sintering phenomena and pebble degradation. • The capability of absorption and desorption of hydrogen isotopes was investigated in the cryogenic molecular sieves adopted in the TES.. • The performance curves (characteristics) of the circulator obtained with the pressure ratio data were well grouped according to the corrected speed and the corrected mass flow rate under the reference conditions of 80 bar and a 50 °C helium flow. Development of the Helium Cooled Ceramic Reflector (HCCR) breeding blanket is underway according to the development strategy of core technology for K-DEMO under the fusion energy development roadmap in Korea. The main goals are to validate integrated design tools and to develop core technologies in the field of materials, manufacturing and joining technologies, helium cooling and tritium technologies, system integration, and safety technologies. A unique graphite reflector concept was adopted to save cost by reducing the amount of beryllium neutron multiplier. The main functions and design concepts of the HCCR breeding blanket are to be verified in ITER through the HCCR Test Blanket Module (TBM) program. Not only breeder modules are to be tested in ITER but also the technologies of cooling, coolant purification, tritium extraction, etc. are to be tested or proved in ITER before employed in DEMO. This paper introduces the current updates of the design and R&D activities of the HCCR TBM systems in the preliminary design stage. [ABSTRACT FROM AUTHOR]