This study aimed to obtain basic information on the indoor environmental hygiene of non-disinfected libraries used for paper records preservation in the Nara Repository of National Archives, Korea. Microorganisms were investigated in dust samples collected from bookshelves of five libraries using the swab method. Bacterial concentration ranged from 6 CFU/m2 up to 1,730 CFU/m2 . A total of 11 bacterial species belonging to five genera were identified, with Bacillus being the predominant genus. Some bacterial species forming colonies with pigmentation on TSA media were also present. No bacterial species capable of producing cellulases were found. However, one species that could have harmful effects on human health was discovered. For fungi, concentration ranged between 6 CFU/m2 to 1,660 CFU/m2, and a total of six fungal species belonging to five genera were found. Some fungal species forming pigmented colonies on PDA media were also present. Additionally, three species that could have harmful effects on human health were identified. This study’s data suggests that microbial contamination in the dust is relatively low, but the dust in the bookshelves of non-disinfected libraries at the Nara Repository requires management. This is the first report conducted on microorganisms in the dust of bookshelves at the National Archives in Korea.

Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.

Airborne bacteria are an important environmental factor that affects the hygiene of mushroom cultivation houses, as they can act as contaminants or pathogens in mushroom cultivation. To determine the distribution of airborne bacteria in the air of wood ear mushroom cultivation houses, air sampling and temperature and humidity measurements were conducted at three wood ear mushroom farms located in Iksan and Wando in 2022. Sampled air was analyzed to measure bacterial concentration levels and identify bacterial species. There was no significant difference in temperature and humidity changes detected between the three mushroom growing houses. Additionally, the concentration of bacteria in the air did not exceed 800 CFU/m², which is the maximum amount of airborne bacteria allowed by the Ministry of Environment’s indoor air quality maintenance standards. Eleven species of bacteria belonging to 11 genera were isolated and identified from air samples. These include five species of Micrococcales, four species of Bacilli, one species of Actinomycetia, and one species of Mycobacteriales. Of the 11 species identified, five are known to affect human health. However, no mushroom pathogens or species causing food poisoning were found.

The present study was carried out to investigate the concentration and species diversity of airborne fungi in thermophilic mushroom cultivation houses. Fungal concentration measurements were performed in April and May 2022 for a Pleurotus ostreatus cultivation house, in July and August 2023 for a Pleurotus sajor-caju and Agaricus blazei cultivation house, and in June, July and August 2023 for a Pleurotus pulmonarius, Pleurotus sajor-caju and Calocybe indica cultivation house. The airborne fungal concentration was 2.95 × 102 CFU/m3~105CFU/m3, above 105CFU/m3, and 1.12 × 103 CFU/m3~ 9.17 × 103 CFU/m3 in the three cultivation houses, respectively. A total of 8 genera and 22 species of airborne fungi were isolated from three mushroom cultivation houses. 5 genera and 7 species were identified from P. ostreatus cultivation house. Furthermore, 4 genera 6 species were found from A. blazei and C. indica cultivation house. In addition, 5 genera and15 species were isolated from P. pulmonarius, P. sajor-caju and C. indica cultivation house. Among the fungi isolated, the class of Eurotiomycetes was the most common. Among the 22 fungal species, Aspergillus flavus, A. ochraceus A. sydowii, A. tubingensis, A. westerdijkiae, Penicillium brevicompactum, P. citrinum, and P. steckii have been reported as harmful species to mushrooms, food, and human.

Airborne bacteria in mushroom growing environments are a potential risk of contamination in commercial mushroom production. Controlling contamination in mushroom farms requires understanding the bacterial ecology in the cultivation environment. This study was conducted to investigate the concentration and species diversity of floating bacteria in a thermophilic mushroom cultivation room. Temperature, humidity, temperature, humidity, and bacterial concentration measurements were performed in April and May 2022 for a Pleurotus ostreatus cultivation house, in July and August 2023 for a Pleurotus sajor-caju and a Agaricus blazei cultivation house, and in June, July and August 2023 for a Pleurotus pulmonarius, Pleurotus sajor-caju and Calocybe indica cultivation house. The airborne bacterial concentration was 5.27 × 103~105 CFU/m3, 3.81 × 102 ~1.37 × 103 CFU/m3, and 2.55 × 102 ~1.37 × 102 CFU/m3 in the three cultivation houses, respectively. A total of 23 genera and 37 species of airborne bacteria were isolated from the three mushroom cultivation houses. 12 genera and 18 species were identified from P. ostreatus cultivation house. Furthermore, 4 genera and 4 species were found from A. blazei and C. indica cultivation house. In addition, 11 genera and 18 species were isolated from P. pulmonarius, P. sajor-caju and C. indica cultivation house. Among the bacteria isolated, the Bacilli class was the most common, followed by Gammaproteobacteria. Among the 37 bacterial species, it was determined that Bacillus cereus, B. licheniformis, Cedecea neteri, Exiguobacterium acetylicum and Raoultella terrigena could negatively affect humans or foodstuff. Cedecea neteri is also known to cause diseases among mushrooms.

To understand microorganism effects on wild mushroom fruiting bodies, we investigated the fungi in hyphosphere soil supporting wild mushroom species Cortinarius violaceus, Amanita hemibapha, Laccaria vinacelavellanea, and Amanita verna found in the Gotjawal area of Jeju Island. Fungal species identification based on morphological traits and molecular analysis of ITS, LSU rDNA, and -tubulin gene sequences resulted in isolation and identification of eleven fungal species previously unrecorded in Korea. These newly-recorded species are: Arthrinium kogelbergensis, Kalmusia longisporum, Keithomyces carneum, Neopyrenochaeta cercidis, Penicillium ranomafanaense, Phomatodes nebulosa, Pyrenochaeta nobilis, Tolypocladium album, Talaromyces kendrickii, Talaromyces qii, and Umbelopsis gibberispora, and their morphological characteristics and phylogenetic positions are described.

The demand for LNG Carrier and LNG fuel ships are increasing due to global carbon neutrality declaration and ship emissions regulation of IMO, domestic shipyards pay technology fees(about 5~10% of ship price per vessel) to GTT company in France for making LNG cargo hold. Localization of LNG cargo hold is needed to reduce technology fees and engage technological competitiveness, it is important to secure the critical technology like automation process development of insulation system process. Especially, the automation rate of membrane-type insulation system is very low due to interference caused by corrugation and difficulty in securing optimal variable welding condition. In this study, to solve this problem, automatic welding is performed using developed automatic welding equipment on STS304L steel which is used in flat and corner area of membrane-type LNG cargo hold's lap joint. After welding, Cross-sectional observations and Tensile strength tests were conducted to evaluate reliability of equipment and welding condition. As a result of the test, it was confirmed that the strength of the welded zone exceeded that of base material, and secured the optimal welding condition to apply automatic welding.

ATP luminescence measurements (using Relative Light Units, RLU) has been used to assess the levels of bacterial contamination on the surfaces of various materials. However, not much is known about their suitability in assessing bacterial contamination on paper surfaces. This study was conducted to evaluate the feasibility of using ATP luminometers in measuring levels of bacteria contamination on paper surfaces. The three ATP luminometers studied were Clean-Q, smart PD-30, and 3M™ Clean-Trace™ LM1 manufactured by different companies. There were some differences in RLU results among the three ATP luminometers when they were tested with different concentrations of Micrococcus luteus cell suspension. 106 - 107 cells were required in order to effectively detect Bacillus subtilis, Escherichia coli, and Micrococcus luteus on the surfaces of A4 printing sheets (100 cm2) when using the three ATP luminometers. The sizes and physical properties of surface areas varied slightly among the swabs used for the three ATP luminometers. Concentration-specific measurements (RLU) of M. luteus taken from the surfaces of six kinds of paper (fine print paper, medium print paper, ground paper, newsprint paper, practice paper, tracing paper) were possible using the smart PD-30 and LM1 ATP luminometers. ATP detection values of M. luteus varied among the six types of paper. The highest ATP detection values were found on the surfaces of tracing paper. If the RLU value is recorded at the level of 1000, this could indicate a very high bacterial contamination level of 105 to 106 CFU/4 cm2.

In order to respond to environmental pollution, developed countries, including Korea, have begun to conduct research to utilize hydrogen energy. For mass transfer of hydrogen energy, storage as liquid hydrogen is advantageous, and in this case, the volume can be reduced to 1/800. As such, the transportation technology of liquefied hydrogen for ships is expected to be needed in the near future, but there is no commercialized method yet. This study is a study on the technology to test the performance of the components constituting the membrane type storage container in a cryogenic environment as a preparation for the above. It is a study to find a way to respond by analyzing in advance the problems that may occur during the shear test of adhesives. Through this study, the limitations of ISO4587 were analyzed, and in order to cope with this, the specimen was supplemented so that fracture occurred in the adhesive, not the adhesive gripper, by using stainless steel, a low-temperature steel, to reinforce the thickness. Based on this, shear evaluation was performed under conditions lowered to minus 243℃, and it was confirmed that the breaking strength was higher at cryogenic temperatures.

Some plant pathogenic bacteria species are environmentally high-risk organisms that have a negative impact on agricultural production. Experiments with these pathogens in a biosafety laboratory require safety protocols to prevent contamination from these pathogens. In this work, we investigated the efficacy of using UV-C irradiation for the purpose of sterilizing an important plant pathogenic bacterium, Erwinia pyrifoliae, in a laboratory setting. For the test, the pathogen (1.71 × 108 CFU/ml) was inoculated on the surface of Potato Dextrose Agar (PDA) and the inoculated media were placed on a work surface in a biosafety cabinet (Class 2 Type A1) as well as on three different surfaces located within the laboratory: a laboratory bench, a laboratory bench shelf, and the floor. All the surfaces where the media were placed were in range of the UV-C beam projected by the UV lamp installed in the ceiling of the BSL 2 Class biosafety laboratory. Measurements of the reduction rate of bacteria under UV-C irradiation were conducted at different time intervals: after 10 minutes, 30 minutes, 1 hour, 2 hours, and 3 hours, respectively. The reduction rate of bacteria ranged from 90% to 99% after 10min irradiation, from 97.8% to 100% after 30 minutes of irradiation, from 99.1% to 100% after 1 hour of irradiation, and from 99.99% to 100% after 2 hours of irradiation. After 3 hours of irradiation, the pathogen was completely killed in all the test conditions. In the cases of the laboratory bench and the shelf of the laboratory bench, the effectiveness of UV-C irradiation differed slightly between the site where the bacteria located vertically under the lamp and the site where the bacteria were located 1 meter away horizontally from the site under of the lamp.

With a rapid expansion in electric vehicles, a huge amount of the spent Li-ion batteries (LIBs) could be discharged in near future. And thus, the proper handling of the spent LIBs is essential to sustainable development in the industry of electrical vehicles. Among various approaches such as pyrometallurgy, hydrometallurgy, and direct recycling, the hydrometallurgical manner has gained interest in recycling the spent LIBs due to its high effectiveness in recycling raw materials (e.g., lithium, nickel, cobalt, and manganese). However, the hydrometallurgical process not only requires the use of large amounts of acids and water resources but also produces toxic gases and wastewater leading to environmental and economic problems, considering potential economic and environmental problems. Thus, this review aims to provide an overview of conventional and state-of-the-art hydrometallurgical processes to recover valuable metals from spent LIBs. First, we briefly introduce the basic principle and materials of LIBs. Then, we briefly introduce the operations and pros-and cons- of hydrometallurgical processes. Finally, this review proposes future research directions in hydrometallurgy, and its potential opportunities in the fundamental and practical challenges regarding its deployment going forward.

High-risk microbial pathogens are handled in a biosafety laboratory. After experiments, the pathogens may remain as contaminants. To safely manage a biosafety laboratory, disinfection of microbial contaminants is necessary. This study was carried out to evaluate the effect of UV-C irradiation for the disinfection of a high-risk plant pathogenic bacterium Erwinia amylovora in a laboratory setting. For the test, the bacterium (8.7 × 106 CFU/ml) was embedded on the surface of PDA and placed on the work surface in a biosafety cabinet (Class 2 Type A1), and on the three different surfaces of the laboratory bench, laboratory bench shelf, and the floor which were positioned in a straight line from the UV lamp installed in the ceiling of the biosafety laboratory (BSL 2 class). UV-C irradiation was administered for 10min, 30min, 1 hr, 2hr, 3 hr, and 4hr, respectively. The reduction rate of bacteria ranged from 95% to 99% in regard to 10 min irradiation, from 97% to 99% in regard to 30 min irradiation, from 99.8% to 99.9% in regard to 1 hr irradiation, and higher than 99.99% in regard to 2 hr irradiation. The bacterium was completely inactivated after 3 hr irradiation. A similar UV-C irradiation effect was obtained when the bacterium was placed at a distance of 1 m from the three different surface points. Bacterial reduction by UV-C irradiation was not significantly different among the three different surface points.