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At specified depths, ground temperature remains almost constant at 15°C, above atmospheric temperatures in winter and below those in summer. Ground thermal energy systems technology circulates water or brine through a heat‐collection tube buried underground and uses the ground thermal energy for air conditioning. However, depending on the facility, the total length of the heat‐collection tube can be several hundred meters. As a result, the pump can require significant electric power. In this study, we adopted a drag‐reduction technique using a cationic surfactant and a counter‐ion system. The optimal addition conditions of additives were investigated with a laboratory‐grade device. We also investigated corrosion inhibitors that do not interfere with the drag‐reduction effect. According to demonstration tests using practical ground thermal energy systems at two locations in Japan, we found that pump power consumption could be reduced by 10%–20% with suitable additive conditions. [ABSTRACT FROM AUTHOR]

Although feeding damage caused by black sea bream Acanthopagrus schlegelii has become severe in the nori Neopyropia yezoensis cultivation industry, the behavioral ecology of black sea bream in nori farms remains unclear. In this study, we monitored black sea bream around a nori farm using acoustic telemetry in order to understand the behavioral characteristics of this species. Of the 23 fish specimens tagged with acoustic transmitters, 18 fish were traced over periods > 100 days, with 8 fish considered to be feeding on cultivated nori. It is thought that the black sea bream, which were inferred to have been feeding on nori, exhibited periodicity in their behavior, feding on cultivated nori near the water surface during the day and settling on the seafloor or around seabed structures during the night. Furthermore, the feeding on nori gradually lessened when the water temperature in the cultivation grounds fell below 13 °C. Some methods aimed at reducing feeding damage are proposed that take advantage of the diurnal behavior of black sea bream to catch individuals around nori sets with gill nets or set nets during the season when the water temperature exceeds 13 °C. [ABSTRACT FROM AUTHOR]

At active volcanoes, the surface temperature and its spatial distribution can indicate changes in the underlying magmatic and hydrothermal system. Surface temperature monitoring has been widely performed using thermal remote sensing with thermal infrared (TIR) cameras. One of the drawbacks of this method is that the unknown viewing orientation of TIR images inhibits quantitative evaluations of the spatial extent and distributions of thermal anomalies. Therefore, many studies have performed 3D temperature-field reconstructions by processing TIR images photogrammetrically. However, these studies have not included the correction of TIR wave atmospheric attenuation and viewing-angle variation in emissivity in the reconstruction procedure, which can result in significant temperature misestimation. We propose a simple method that incorporates the correction into the reconstruction process, which can improve the estimation of surface temperature, especially in rugged terrains. We demonstrate our method for the active crater of Aso volcano in Japan. We create digital elevation models by applying the Structure from Motion–Multi-view Stereo algorithm to aerial visible images taken at the same time as the TIR images and then project the TIR images onto the DEM with the direct georeferencing method. The correction is carried out using the geometric parameters acquired in the process. We create 1-m resolution orthorectified thermal images of the crater on two separate dates (18 August 2020 and 16 March 2022) and calculate the heat discharge rates from steaming grounds and a volcanic lake. We find that the heat discharge rate from the fumarolic field on the south crater wall showed a sevenfold increase after the phreatic explosions that occurred on 14 and 20 October 2021. [ABSTRACT FROM AUTHOR]

This work introduces a pilot-scale experiment conducted for 18 months to study the soil heating performance of solar collectors in Japan for borehole thermal energy storage and thermal consolidation applications. In this experiment, water was heated using a solar collector and then circulated in three heat exchangers inserted into a 2.63-m3 box of kaolin clay installed in sandy ground. The solar collector had a heat collection area of 4 m2 and was attached to a 200-L water tank. The tank containing the clay was internally lined by a 6-cm-thick box of polyethylene foam to reduce heat exchange with the environment. The average clay temperature reached a maximum value of 41.1°C in the summer and a minimum of 14.9°C in the winter. The circulation water temperature varied seasonally between a daytime maximum of 77.5°C in summer and a daytime minimum of 22.5°C in winter. The experiment was simulated using a finite-element analysis model based on thermal conduction. The model used the Dittus–Boelter equation to model the heat exchangers' energy output and adopted an environmental heat exchange boundary condition using ambient temperature, wind speed, and total daily solar flux data. The numerical results accurately predicted the ground and average kaolin temperature within a 2°C–3°C margin of error. The numerical and experimental spatial distributions of kaolin temperature suggest that gravity and temperature-induced moisture transport was sufficient to measurably change the kaolin water content. Additionally, the numerical results of the sandy ground temperature revealed its sensitivity to variation of moisture content induced by evapotranspiration. Last, changing the boundary condition of the kaolin box to thermal insulation revealed that environmental heat loss accounted for a 13.5°C–19.5°C difference in the average kaolin temperature between the numerical and experimental results, emphasizing the importance of adequate thermal insulation in ground heating applications. [ABSTRACT FROM AUTHOR]

This study predicts the long-term performance of ground source heat pump (GSHP) systems in different climatic regions of Japan. The research model calculates the dynamic heat load of a typical Japanese building in various cities using their meteorological data, considering different schedules for heating and cooling seasons. The model aims to analyze the performance degradation of the GSHP system after 15 years of operation due to the imbalanced heating and cooling loads. Additionally, it compares ground temperature changes, coefficient of performance (COP) variations, and annual operation times based on different thermal imbalance ratios (TIR) for the case studies. The results demonstrate that TIR serves as an appropriate factor for comprehensively evaluating system aspects, including GHE length, ground temperature, and COP degradation, across various climates. It was found that ground temperatures increased by a maximum of up to 4 °C in cooling-dominated regions due to higher thermal imbalance accumulative loads, while it decreased to around 1 °C in heating-dominated regions. The model also revealed that the COP decreased in the dominant operation for each case study due to induced thermal imbalance and soil temperature change. The thermal imbalance caused the system cooling COP decreased by 0.015/year in the worst case (Okinawa City) and 0.006/year in average for other cases. (1) The climatic regions of japan and the color-coded average hourly temperature for the different cities. (2) This variety causes different cooling and heating season schedules, imbalance load, and (3) Changes the ground temperature in long-term operation. [Display omitted] [ABSTRACT FROM AUTHOR]

Sustainable methods are required to reduce the risks of thermal strain and heat-related illness without exacerbating greenhouse gas emissions. We investigated the effects of sun-shade use on safe heat exposure limit on a sunny summer day using historical climate data in Japan. We simulated a heat-acclimatised person standing at rest (metabolic heat production, 70 W·m−2) and during light work (100 W·m−2) on an asphalt pavement in the sun and sun-shade. Japan has three Köppen climate regions: tropical, temperate and cold. We analysed one city in the tropical region (24°N), three cities in the temperate region (31°N, 35°N and 39°N) and one city in the cold region (40°N). Hourly data were collected from 7 AM to 6 PM, June to September, from 2010 to 2019. The day with the longest daylight hours and the greatest solar radiation intensity was used for analysis. With sun-shade (a white polyester tarpaulin/awning), ambient temperature, global solar radiation and ground surface temperature were assumed to be 0.5°C, 45% and 6°C lower than in the sun, respectively. Sun-shade use eliminated the days with at least 1 hour exceeding safe heat exposure limit at rest in all cities. The same was observed for light work in the temperate and cold cities, although the tropical city had 2 days exceeding safe heat exposure limit during the decade. Sun-shade use on a sunny summer day can be an effective and sustainable method to reduce heat exposure hazard at rest and during light work in tropical, temperate and cold climate regions. [ABSTRACT FROM AUTHOR]

Major change in the Earth’s surface temperature appears to be the most critical and universal factor for inducing coevally multiple kill mechanisms for organisms during the global environmental change episodes. Among the major extinction events during the Phanerozoic, the end-Ordovician episode shares almost the same environmental background with that of the end-Guadalupian (middle Permian). These two major extinction-relevant episodes, however, occurred respectively before and after the mid-Palaeozoic botanical revolution, i.e., the first mass development of land plants/forests. Owing to the enhanced terrestrial photosynthesis, the atmospheric CO2 content decreased irreversibly from ca. 2800–800 ppm in the Ordovician down to 400–300 ppm in the Permian. This highlights an apparent contradiction between the end-Ordovician glaciation and distinctly high atmospheric pCO2, which may suggest that one or more agents on global scale were likely responsible for the prominent global cooling besides atmospheric pCO2 with respect to the greenhouse effect. The same conundrum is much clearer in the cases of Proterozoic snowball Earth events. Ancient mid-oceanic sedimentary rocks, i.e., deep-sea cherts and atoll carbonates on top of seamounts, are valuable in recording the average regional/global changes of past oceanic domains without receiving tectonic disturbances along continental margins. The Permian mid-oceanic deep-sea cherts and paleo-atoll carbonates in South-West Japan were deposited in the mid-Panthalassa superocean that occupied nearly 70% of the Earth’s surface (the rest 30% by Pangea). The latest research results from these unique sedimentary archives in Japan are introduced with particular focus on the hiatus-bearing sea-level drop and a unique signature of extraordinarily high ³He enrichment in the extinction-relevant interval. These new lines of evidence imply non-bolide extraterrestrial agent for driving global cooling/sea-level drop. Comparative discussion with the end-Ordovician episode may open a new window for extinction study. [ABSTRACT FROM AUTHOR]