A facile and efficient method was developed to prepare highly stretchable and conductive graphene conductors with wrinkled structures by the mechanical stretching and shrinking of elastomeric substrates, in which graphene inks were printed on a prestretched elastomeric substrate. Stretchable and exfoliated graphene inks were prepared by mixing graphite and Ecoflex in a shear-assisted fluid dynamics reactor. The resultant graphene conductor exhibited excellent stretchability at 150% strain and high electrical conductivity of 64 ± 1.2 S m− 1. The resistance of the conductor did not change in bent, twisted, and stretched states. The resistance did not change during 10,000 cycles of stretching/releasing, with a maximum strain of 150%. Based on the graphene conductor, a stretchable conductometric sensor with a two-electrode configuration was fabricated to measure impedance changes at different concentrations of electrolyte ions. This sensor exhibited a good and linear sensitivity curve (298.61 Ω mM− 1, R2 = 0.999) in bent and stretched states.

L-asparaginase (ASNase) is a therapeutic enzyme used to treat acute lymphoblastic leukemia. Currently, the most widely used ASNases are originated from bacteria. However, owing to the adverse effects of bacterial ASNases, new resources for ASNase production should be explored. Fungal enzymes are considered efficient and compatible resources of natural products for diverse applications. In particular, fungal species belonging to the genus Trichoderma are well-known producers of several commercial enzymes including cellulase, chitinase, and xylanase. However, enzyme production by marine-derived Trichoderma spp. remains to be elucidated. While screening for extracellular ASNase-producing fungi from marine environments, we found four strains showing extracellular ASNase activity. Based on the morphological and phylogenetic analyses using sequences of translation elongation factor 1-alpha (tef1α), the Trichoderma isolates were identified as T. afroharzianum, T. asperellem, T. citrinoviride, and Trichoderma sp. 1. All four strains showed different ASNase activities depending on the carbon sources. T. asperellem MABIK FU00000795 showed the highest ASNase value with lactose as a carbon source. Based on our findings, we propose that marine-derived Trichoderma spp. are potential candidates for novel ASNase production.

The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I0, I25, and I50 (where irrigation volume of I25 and I50 was 25% and 50% higher than I0, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I0 treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I25 and I50 treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I0) than the higher volume (I25 or I50). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I0 treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I25 irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I0 treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I0 treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I25 was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.

Molten salts based on magnesium chloride can be used in the nuclear power reactor because they have a high heat capacity and heat stability, and allow for a faster neutron spectrum. However, magnesium chloride is highly hygroscopic, leading to the formation of moisture-related impurities, which result in the corrosion of structural materials and negatively affect the operation of the reactor. The dehydration of magnesium chloride is studied using both thermal and electrochemical treatments. According to previous studies, water impurities in magnesium chloride molten salt transform into magnesium oxide over 650 degrees Celsius. The temperature profile of the molten salt is suggested to separate magnesium chloride and magnesium oxide, focusing on cooling rate near the freezing point of magnesium chloride. Two layers separated by a phase boundary on the salt surface appear due to the density difference between magnesium oxide and magnesium chloride. Further, the removal of oxide ions remaining in the molten salt is carried out by electrochemical treatment. Two different cells, each consisting of two electrodes, are used. One cell is composed of graphite anode and nickel cathode. The other is composed of tin oxide anode and nickel cathode. As the reaction proceeds, carbon dioxide and oxygen are generated in graphite and tin oxide, respectively, and magnesium electrodeposition occurs at the cathode. The amount of purified magnesium oxide is measured to the endpoint, which is notified by the reduced current. The efficiency of each method is compared by measuring the weight ratio of the purified part to the unpurified part. Thermogravimetric analyzer (TGA) and UV-vis spectroscopy are used to check the quality of the purified part. Only magnesium oxide remains at a temperature above the boiling point of magnesium chloride. Therefore, the amount of magnesium oxide in the purified part can be measured by the mass change of the salt through the TGA method. For UV-vis spectroscopy, the transmittance is measured which depends on the weight percent of the impurities in the purified part. The suggested purification method using both thermal and electrochemical treatment is assessed quantitatively and qualitatively. It is expected that hygroscopic molten salts other than magnesium chloride will be able to be dehydrated through the above process.

Molten chloride salts are promising candidates as a coolant for Molten Salt Reactors (MSRs) because of their low cost, high specific heat transfer, and thermal energy storage capacity. The NaCl- MgCl2 eutectic salts have enormous latent heat (430 kJ/kg) and financial advantage over other types of molten chloride salt. Despite the promise of the NaCl-MgCl2 eutectic salt, problems associated with structural material corrosion in the MSR system remain. The hygroscopicity of NaCl-MgCl2 and high MSRs operating temperature accelerate corrosion within structural alloys. Especially, MgCl2 reacts with H2O in the eutectic salt to produce HCl and Cl2, which are known to further exacerbate corrosion by the chlorination of structural materials. Therefore, several studies have worked to purify impurities associated with MgCl2, such as H2O. Thermal salt purification of NaCl-MgCl2 eutectic salt is one method that reduces HCl and Cl2 gas generation. However, MgO and MgOHCl are generated as the byproduct of thermal purification through a reaction between MgCl2 and H2O. The corrosion behavior of MgO within structural alloys after thermal treatment is not well known. This paper demonstrates corrosion behavior within structural alloy after thermal treatment at various temperature profiles of the NaCl-MgCl2 eutectic salt. According to the temperature range, MgCl2·H2O are separated at 100~200°C, and MgOHCl and HCl begin to occur at 240°C or higher. Finally, MgOHCl produces MgO and HCl at 500°C or higher temperatures. After thermal treatments, the H2O, MgOHCl, and MgO content were measured by Thermo Gravimetric Analyzer (TGA) to evaluate significant products causing corrosion. The structural materials were analyzed by the Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) and using the mass change method to observe the type of localized corrosion, the corrosion rate, and the corrosion layer thickness. This study is possible in that it can reduce economic costs by reducing the essential use of expensive, high-purity molten salts because it is related to a substantial financial cost problem considering the amount of molten salt used in industrial sites.

Corrosion products generated from the oxidation of structure materials are deposited on the surface of coolant systems, forming CRUD (Corrosion Related Unidentified Deposits). The CRUD deposition on the fuel surface has influenced the heat transfer through the fuel rod. When CRUD was deposited on a fuel surface, heat resistance may increase, and this increase in heat resistance leads to the increase in temperature distribution from cladding to coolant. Also, the temperature distribution is related to the radiolytic and chemical reactions within the CRUD deposits. This influence may be enough to change the pH distribution within the CRUD deposits. To estimate the influence of thermal resistance, the composition, microstructure, and vapor fraction within the CRUD should be considered, by investigating the thermal conductivity model of CRUD deposits. Therefore, in this study, the CRUD thermal conductivity was studied through the literature study, by considering composition, capillary flow characteristics, and vapor fraction. For the uncertainty parameters, a sensitivity study was conducted to check the degree of influence on thermal conductivity. The effective thermal conductivity was applied to the radiochemistry model within the CRUD deposits and an analysis of the influence in radiolysis reaction within the CRUD deposits with a fixed thickness.