Thermal dehydration tests of FLiNaK salt for thermal-hydraulic experiments

Che Shuai,Zhang Sheng,Burak Adam,Sun Xiaodong 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.3

Fluoride-salt-cooled High-temperature Reactor (FHR) is a promising nuclear reactor technology. Among many challenges presented by the molten fluoride salts is the corrosion of salt-facing structural components. Higher moisture contents, in the FLiNaK (LiF-NaF-KF, 46.5–11.5-42 mol%) salt, aggravate intergranular corrosion and pitting for the given alloys. Therefore, several thermal dehydration tests of FLiNaK salt were performed with a batch size suitable for thermal-hydraulic experiments. Thermogravimetric Analysis (TGA) was performed for the three constituent fluoride salts individually. Preliminary thermal dehydration plans were then proposed for NaF and KF salts based on the TGA curves. However, the dehydration process may not be required for LiF since its low mass loss (<1.3 wt%). To evaluate the performance of these thermal dehydration plans, a batch-scale salt dehydration test facility was designed and constructed. The preliminary thermal dehydration plans were tested by varying the heating rates, target temperature, and holding time. The sample mass loss data showed that the high temperatures (>500 ◦C) were necessary to remove a significant amount of moisture (>1 wt%) from NaF salt, while relatively low temperatures (around 300 ◦C) with a long holding time (>10 h) were sufficient to remove most of the moisture from KF salt.

Effects of sludge pyrolysis temperature and atmosphere on characteristics of biochar and gaseous products

Shuai Guo,Xiaoyan Xiong,Deyong Che,Hongpeng Liu,Baizhong Sun 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.1

In view of the importance of inert-atmosphere sludge pyrolysis for effective waste recycling and carbon emission reduction, this study probed the effects of temperature (300-700 oC) and atmosphere (100% N2, 10 CO2/90% N2, or 100% CO2) on the properties of biochar and gases obtained by sludge pyrolysis in a horizontal tube furnace. The emissions of NO, SO2, H2S, and CO increased with increasing temperature, as the inhibitory effect of CO2 on the formation of these gases (observed at <500 oC) concomitantly weakened and was superseded by the reaction of CO2 with carbon at higher temperature to afford gaseous products. The specific surface area (SBET) and pore volume of the biochar produced in the presence of CO2 increased with increasing temperature up to 500 oC, while at higher temperatures the inhibitory effect of CO2 on pore structure development resulted in a decreased SBET and an increased macropore content. These results show that pyrolysis is an effective treatment method for sludge; it can remove 48% N and 50% S in sludge and mitigate the emission of polluting gases. When CO2 participates in the pyrolysis reaction, the SBET of biochar increases significantly. In general, sludge biochar has the potential to be applied as fuel and as an adsorbent.

Response surface analysis of energy balance and optimum condition for torrefaction of corn straw

Shuai Guo,Tiankuo Guo,Deyong Che,Hongpeng Liu,Baizhong Sun 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.5

Corn straw has potential as a biofuel, and is generated in large amounts globally. However, this potentialremains underutilized, and torrefaction is one of the processes that can be implemented to improve the energy grade ofthis biomass. In this study, three process parameters (temperature, heating rate, residence time) were investigated usinga response surface method to optimize the torrefaction process of corn straw. At 242.26 oC, a 60 min residence time,and 6.28 oC/min heating rate, the mass yield and higher heating value (HHV) reached their maximum values. Temperaturewas the most important factor influencing torrefaction, followed by residence time and then heating rate. Thegas and liquid by-products were measured by mass spectrometry and mass spectrometry-gas chromatography, and theheat demand of torrefaction was measured by thermogravimetric analysis-differential scanning calorimetry. The HHVof the by-products changed little before 240 oC but increased considerably as the temperature further increased. TheHHV at 242 oC was 1,273 kJ/kg. When the heat loss was 50%, 242 oC was the critical point of energy balance, and afterthat the torrefaction process was energy self-sufficient. These findings provide data to support the establishment ofsemi-industrial or industrial corn straw torrefaction devices.

Rapid and Efficient Detection of 16SrI Group Areca Palm Yellow Leaf Phytoplasma in China by Loop-Mediated Isothermal Amplification

Shao-shuai Yu,Hai-yan Che,Sheng-jie Wang,Cai-li Lin,Ming-xing Lin,Wei-wei Song,Qing-hua Tang,Wei Yan,Wei-quan Qin 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.5

Areca palm yellow leaf (AYL) disease caused by the 16SrI group phytoplasma is a serious threat to the development of the Areca palm industry in China. The 16S rRNA gene sequence was utilized to establish a rapid and efficient detection system efficient for the 16SrI-B subgroup AYL phytoplasma in China by loopmediated isothermal amplification (LAMP). The results showed that two sets of LAMP detection primers, 16SrDNA-2 and 16SrDNA-3, were efficient for 16SrIB subgroup AYL phytoplasma in China, with positive results appearing under reaction conditions of 64oC for 40 min. The lowest detection limit for the two LAMP detection assays was the same at 200 ag/μl, namely approximately 53 copies/μl of the target fragments. Phytoplasma was detected in all AYL disease samples from Baoting, Tunchang, and Wanning counties in Hainan province using the two sets of LAMP primers 16SrDNA-2 and 16SrDNA-3, whereas no phytoplasma was detected in the negative control. The LAMP method established in this study with comparatively high sensitivity and stability, provides reliable results that could be visually detected, making it suitable for application and research in rapid diagnosis of AYL disease, detection of seedlings with the pathogen and breeding of diseaseresistant Areca palm varieties.

Physiological response of red macroalgae Pyropia yezoensis (Bangiales, Rhodophyta) to light quality: a short-term adaptation

Xuefeng Zhong,Shuai Che,Congying Xie,Lan Wu,Xinyu Zhang,Lin Tian,Chan Liu,Hongbo Li,Guoying Du The Korean Society of Phycology 2023 ALGAE Vol.38 No.2

Light quality is a common environmental factor which influences the metabolism of biochemical substances in algae and leads to the response of algal growth and development. Pyropia yezoensis is a kind of economic macroalgae that naturally grows in the intertidal zone where the light environment changes dramatically. In the present study, P. yezoensis thalli were treated under white light (control) and monochromatic lights with primary colors (blue, green, and red) for 14 days to explore their physiological response to light quality. During the first 3 days of treatment, P. yezoensis grew faster under blue light than other light qualities. In the next 11 days, it showed better adaptation to green light, with higher growth rate and photosynthetic capacity (reflected by a higher rETR_max = 61.58 and E_k = 237.78). A higher non-photochemical quenching was observed in the treatment of red light than others for 14 days. Furthermore, the response of P. yezoensis to light quality also results in the difference of photosynthetic pigment contents. The monochromatic light could reduce the synthesis of all pigments, but the reduction degree was different, which may relate to the spectral absorption characteristics of pigments. It was speculated that P. yezoensis adapted to a specific or changing light environments by regulating the synthesis of pigments to achieve the best use of light energy in photosynthesis and premium growth and metabolism.

Effects of Continuous Straw Returning on Soil Functional Microorganisms and Microbial Communities

Guan Yunpeng,Wu Meikang,Che Songhao,Yuan Shuai,Yang Xue,Li Siyuan,Tian Ping,Wu Lei,Yang Meiying,Wu Zhihai 한국미생물학회 2023 The journal of microbiology Vol.61 No.1

This study examined the changes in soil enzymatic activity, microbial carbon source metabolic diversity, and straw decomposition rates in paddy fields treated with 1, 2, or 3 years of straw returning (SR1–SR3). The soil’s ability to decompose straw and cellulolytic bacteria increased with the number of treatment years (1: 31.9% vs. 2: 43.9% vs. 3: 51.9%, P < 0.05). The numbers of Azotobacter, Nitrobacteria, cellulolytic bacteria, and inorganic phosphate bacteria increased progressively with the numbers of straw returning years. Cellulolytic bacteria and inorganic phosphate bacteria were significantly positively correlated with the decomposition rate (r = 0.783 and r = 0.375, P < 0.05). Based on 16S sequencing results, straw returning improved the microbial diversity of paddy soils by increasing unclassified bacteria and keeping dominant soil microorganism populations unchanged. The relative importance of individual microbial taxa was compared using random forest models. Proteobacteria, ammoniating bacteria, and potassium dissolving bacteria contributed to peroxidase activity. The significant contributors to phosphate monoesterase were Acidobacteriota, Desulfobacterota, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria. Proteobacteria, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria contributed to urease activity. Desulfobacterota, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria contributed to the neutral invertase activity. In conclusion, soil microbial community structure and function were affected within 2 years of straw returning, which was driven by the combined effects of soil organic carbon, available nitrogen, available potassium, and pH. With elapsing straw returning years, soil properties interacted with soil microbial communities, and a healthier soil micro-ecological environment would form.

Removal of Acid Red G dye from aqueous solutions by adsorption to MCM-41-layered double hydroxides composite

Yisong Wang,Tao Du,Lifeng Zhou,Yanli Song,Shuai Che,Xin Fang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.3

MCM-41 supported layered double hydroxides (LDH) composite materials (ML) were synthesized and studied for removal of Acid Red G (ARG), an anionic dye, with the adsorption method. ML was prepared using in situ synthesis procedure for the low supersaturation coprecipitation method, and ML10 and ML20 presented promising application towards ARG dye adsorption capacity in industrial wastewater. Powder samples were characterized by Xray diffraction, FTIR spectroscopy, scanning electron microscopy and energy dispersive spectrometry. The effects of different reaction time, initial solution pH and temperature on the dye adsorption capacity were investigated. Adsorption process was well described by pseudo-second-order kinetic model and Langmuir isotherm model. The fitting curves showed that ML10 and ML20 had higher adsorption rates and maintained a certain theoretical saturated adsorption capacity (92.19807mg/g and 96.41947mg/g, respectively) compared with LDH.

ALKBH5 facilitates CYP1B1 mRNA degradation via m6A demethylation to alleviate MSC senescence and osteoarthritis progression

Ye Guiwen,Li Jinteng,Yu Wenhui,Xie Zhongyu,Zheng Guan,Liu Wenjie,Wang Shan,Cao Qian,Lin Jiajie,Su Zepeng,Li Dateng,Che Yunshu,Fan Shuai,Wang Peng,Wu Yanfeng,Shen Huiyong 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Improving health and delaying aging is the focus of medical research. Previous studies have shown that mesenchymal stem cell (MSC) senescence is closely related to organic aging and the development of aging-related diseases such as osteoarthritis (OA). m6A is a common RNA modification that plays an important role in regulating cell biological functions, and ALKBH5 is one of the key m6A demethylases. However, the role of m6A and ALKBH5 in MSC senescence is still unclear. Here, we found that the m6A level was enhanced and ALKBH5 expression was decreased in aging MSCs induced by multiple replications, H2O2 stimulation or UV irradiation. Downregulation of ALKBH5 expression facilitated MSC senescence by enhancing the stability of CYP1B1 mRNA and inducing mitochondrial dysfunction. In addition, IGF2BP1 was identified as the m6A reader restraining the degradation of m6A-modified CYP1B1 mRNA. Furthermore, Alkbh5 knockout in MSCs aggravated spontaneous OA in mice, and overexpression of Alkbh5 improved the efficacy of MSCs in OA. Overall, this study revealed a novel mechanism of m6A in MSC senescence and identified promising targets to protect against aging and OA.