摘要：
More and more researchers are focusing on the service condition of operational tunnel structures. In sulfate strata, tunnel lining structures are frequently affected by sulfate erosion, resulting in structural damage. However, the fracture evolution law and destabilization damage precursors of lining structures after erosion are not clear at present. Therefore, this study aimed to analyze the failure precursors of concrete subjected to sulfate erosion by testing the uniaxial compressive strength and acoustic emission (AE) phenomenon of the specimens. The b -value in the G -R law was utilized to characterize the damage precursors of the concrete specimens during the loading process. The results indicated that the b -value changes during the loading process of the specimens exhibited distinct three -stage characteristics. Moreover, the high concentration of sulfate erosion resulted in the expansion of numerous pore -fracture structures within the concrete, and the AE was more active at all stages. Furthermore, the multifractal detrended fluctuation analysis (MF-DFA) method was employed to analyze the multifractal characteristics of the AE sequences at different stages. The findings revealed that the multifractal intensity of the AE sequences at different stages of uniaxial compression of eroded concrete is greater. In addition, for the non -eroded concrete specimen, the multifractal eigenvalue Delta f(alpha) is slightly higher during the pore -fracture compaction stage, which was dominated by weak AE signals. Strong AE signals dominate during the yielding stage, resulting in greater fluctuations in the multifractal eigenvalue Delta f(alpha) and a significant decrease in the AE b -value. In contrast, the eroded concrete specimens exhibited smaller eigenvalues Delta f(alpha) during the pore -fracture compaction stage, indicating more strong AE signals. During the yield stage, the specimens showed a decreasing trend in Delta f(alpha), accompanied by fluctuating b -value. Overall, the AE multifractal characteristics and b -value of concrete specimens are correlated and can be used to characterize the damage precursors of concrete subjected to sulfate erosion. The conclusions of the study are of theoretical significance and application value for the stability monitoring and damage prediction of tunnel linings in sulfate formations.
关键词：
biomass hot air furnace;adaptive fuzzy PID;temperature control;simulink simulation
摘要：
Timely and effective drying of agricultural products is crucial for ensuring the quality and yield of grains. Biomass drying enhances energy utilization and reduces energy pressure. To this end, a novel multi-channel circulating biomass hot air furnace was designed to provide precise control of the heat source for grain drying, thereby improving the efficiency and quality of the drying process. The combustion process utilizes a multi-channel combined air supply to ensure complete combustion of biomass pellet fuel. During the heat exchange process, heat exchange plates isolate hot and cold areas, discharging combustion exhaust, while ensuring a pure air output. Using rapeseed as the drying subject, a temperature controller based on adaptive fuzzy PID was designed, targeting the biomass hot air furnace's heat exchange system for modeling and verifying the model with the step response method. Model simulations were conducted in Matlab's Simulink module using both adaptive fuzzy PID and traditional PID controllers, for a given signal. The settling times for the conventional PID and fuzzy PID were 445 s and 364 s, respectively, with overshoots of 20.1% and 6.3%, showing that the fuzzy PID controller performed better in terms of control performance. The validation tests showed that both control methods could maintain the temperature within +/- 5 degrees C. Compared to traditional PID control, the adaptive fuzzy PID control achieved a precision of +/- 3 degrees C. At the target temperature of 90 degrees C, the error was reduced to 3.7%, with a stabilization time of 1014 s. The use of fuzzy PID control exhibited better dynamic response characteristics, meeting the drying needs of rapeseed. This study provides a theoretical basis for the structural design and control system design of biomass hot air furnaces.
摘要：
Anthocyanins are the most important compounds for nutritional quality and economic values of blood orange. However, there are few reports on the pre-harvest treatment accelerating the accumulation of anthocyanins in postharvest blood orange fruit. Here, we performed a comparative transcriptome and metabolomics analysis to elucidate the underlying mechanism involved in seasonal drought (SD) treatment during the fruit expansion stage on anthocyanin accumulation in postharvest ‘Tarocco’ blood orange fruit. Our results showed that SD treatment slowed down the fruit enlargement and increased the sugar accumulation during the fruit development and maturation period. Obviously, under SD treatment, the accumulation of anthocyanin in blood orange fruit during postharvest storage was significantly accelerated and markedly higher than that in CK. Meanwhile, the total flavonoids and phenols content and antioxidant activity in SD treatment fruits were also sensibly increased during postharvest storage. Based on metabolome analysis, we found that substrates required for anthocyanin biosynthesis, such as amino acids and their derivatives, and phenolic acids, had significantly accumulated and were higher in SD treated mature fruits compared with that of CK. Furthermore, according to the results of the transcriptome data and weighted gene coexpression correlation network analysis (WGCNA) analysis, phenylalanine ammonia-lyase (PAL3) was considered a key structural gene. The qRT-PCR analysis verified that the PAL3 was highly expressed in SD treated postharvest stored fruits, and was significantly positively correlated with the anthocyanin content. Moreover, we found that other structural genes in the anthocyanin biosynthesis pathway were also upregulated under SD treatment, as evidenced by transcriptome data and qRT-PCR analysis. The findings suggest that SD treatment promotes the accumulation of substrates necessary for anthocyanin biosynthesis during the fruit ripening process, and activates the expression of anthocyanin biosynthesis pathway genes during the postharvest storage period. This is especially true for PAL3, which co-contributed to the rapid accumulation of anthocyanin. The present study provides a theoretical basis for the postharvest quality control and water-saving utilization of blood orange fruit.
摘要：
Micromelalopha sieversi (Staudinger, 1892) is a significant pest of Poplar trees in China. In this study, we used high-throughput sequencing to sequence the whole mitochondrial genome of M. sieversi. The length of the genome was 15,373 base pairs. The nucleotide composition was 39.8%, 11.5%, 8.0%, and 40.7% for A, C, G, and T, respectively. We used the maximum-likelihood method to construct a molecular phylogenetic tree based on complete mitogenome sequences of 19 Noctuoidea species as ingroups and five Geometroidea species as outgroups. The results indicate that the genus Micromelalopha is closely related to the genus Clostera in family Notodontidae.
摘要：
This study aimed to analyze the effect of 1-methylcyclopropene (1-MCP) treatment on the postharvest quality, epidermal wax morphology, composition, and gene expression of Jinxiu yellow peach during cold storage. The results showed that 1-MCP treatment could maintain the postharvest quality of peach fruit as compared to control (CK) during cold storage. The wax crystals of peach fruit were better retained by 1-MCP, and they still existed in 0.6 and 0.9 µL/L 1-MCP treated fruit at 36 days. The total wax content in all the fruit increased first and then decreased during cold storage. Meanwhile, n-alkanes and primary alcohols were the main wax components. Compared to CK, 1-MCP treatment could delay the reduction of wax content during cold storage. The correlation analysis indicated that the postharvest quality of yellow peach was mainly affected by the contents of fatty acids and triterpenoids in cuticular wax. The transcriptomics results revealed PpaCER1, PpaKCS, PpaKCR1, PpaCYP86B1, PpaFAR, PpaSS2, and PpaSQE1 played the important roles in the formation of peach fruit wax. 1-MCP treatment upregulated PpaCER1 (18785414, 18786441, and 18787644), PpaKCS (18774919, 18789438, and 18793503), PpaKCR1 (18790432), and PpaCYP86B1 (18789815) to deposit more n-alkanes and fatty acids during cold storage. This study could provide a new perspective for regulating the postharvest quality of yellow peach in view of the application of cuticular wax. PRACTICAL APPLICATION: 'Jinxiu' yellow peach fruit is favorable among consumers because of its high commercial value. However, it ripens and deteriorates rapidly during storage, leading to serious economic loss and consumer disappointment. The effect of 1-methylcyclopropene (1-MCP) treatment on the postharvest quality, epidermal wax morphology, composition, and genes regulation of 'Jinxiu' yellow peach during cold storage was assessed. Compared to control, 1-MCP treatment could retain the storage quality of yellow peach by affecting cuticular wax composition and gene expression. This study could provide new perspective for regulating the postharvest quality of yellow peach in view of the application of cuticular wax.
摘要：
Polycyclic aromatic hydrocarbons (PAHs), a group of seriously hazardous environmental contaminants, have attracted extensive attention due to their carcinogenicity, genotoxicity, mutagenicity, and ubiquity. In this work, the excellent hydrophobic trifluoromethyl-enriched covalent organic framework (CF(3)-COF) was designed and synthesized as coating of solid-phase microextraction (SPME). The CF(3)-COF offered a high adsorption selectivity for PAHs, which could be attributed to the multiple interactions between the CF(3)-COF and PAHs, including hydrophobicity interaction, π-π and H bond interactions. Furthermore, headspace (HS) and direct immersion (DI) dual-mode solid-phase microextraction (HS/DI-SPME) were innovatively integrated as a dual-mode extraction by varying the length of SPME coating on stainless-steel, which could simultaneously and efficiently extract 16 PAHs with different volatile. Amazingly, the proposed strategy achieved fast adsorption for PAHs and shortened the adsorption equilibrium time to 15min. By further integrating with gas chromatography tandem mass spectrometry (GC-MS/MS), PAHs could be detected in the range of 0.008-0.16ngmL(-1) with a quantitative limit of 0.029-0.47ngmL(-1), respectively. The recoveries of PAHs in water samples ranged from 80.84 to 117.67%. This work indicates that the dual-mode CF(3)-COF-SPME is a promising candidate for the enrichment of multiple hazardous substances in complicated samples.
摘要：
This paper investigates the impact of environmental courts on pollution abatement at the city level, utilizing the establishment of environmental courts in China as a quasi-experiment. A spatial difference-in-differences model is employed to control for the influence of environmental courts on neighbouring non-pilot cities. The results underscore the effectiveness of environmental courts in reducing industrial pollutant emissions, evident in both the pilot areas and adjacent non-pilot areas. The influence of environmental courts on pollution abatement is more pronounced in cities characterized by stronger environmental regulations, higher level of economic agglomeration, and higher level of openness. Mechanism analysis shows that environmental courts promote environmental supervision by governments, public participation in environmental protection, and expenditure on environmental governance by firms. In summary, this paper unveils the tangible effects of environmental courts on pollution abatement and elucidates the mechanisms underpinning this relationship. These findings provide timely implications for regulators concerned with environmental protection.
摘要：
Efforts to curtail the escalating health threat posed by methicillin-resistant Staphylococcus aureus (MRSA), a formidable superbug, necessitate the development of innovative treatment strategies. Leveraging potential compounds from natural sources in tandem with antibiotics has emerged as a promising approach against MRSA. These strategies should enhance the antibiotic efficacy, reduce dosage and toxicity, and bypass MRSA resistance. In this study, we used a checkerboard assay to illustrate the significant synergistic anti-MRSA effect of shikimic acid (SA), a naturally occurring compound, and ceftiofur (CF). Time-kill curves further revealed that a combination of 1/4 of the minimum inhibitory concentration (MIC) of SA and 1/8 MIC of the sodium CF eradicated MRSA within 2h, with no noticeable toxicity observed with these concentrations. In vivo experiments confirmed that this combination therapy demonstrated robust antimicrobial activity against MRSA-induced bacteremia in mice, significantly reducing bacterial loads in the kidneys, liver, and spleen, attenuating inflammatory cell infiltration, and alleviating pathological damage. This study not only offers a compelling strategy, capitalizing on the synergistic potential of SA and CF, to rapidly address antibiotic resistance but also contributes significantly to the refinement of antimicrobial therapeutic strategies.
摘要：
Engelmann spruce (Picea engelmannii) is one of the most economically important tree species in the western United States. The species is widely distributed in mid- to high-elevation mountains, so its vulnerability to wind and snow is of concern to foresters. Height-to-diameter (H-D) ratio is an important metric for assessing tree stability and resistance to windstorm and icing damage. But our understanding of the variation in H-D ratio of Engelmann spruce and its driving mechanism is limited. Based on inventory data of 9004 Engelmann spruce trees from 997 permanent plots, this study used the random forest algorithm, an important machine learning method, to develop the H-D ratio model of Engelmann spruce related to competition, site condition, climate, topography and other environmental variables. We used cross-validation to train and optimize H-D ratio model, and then used variable importance ranking and partial dependence plot to quantify and analyze the effects of environmental factors on H-D ratio. Further, structural equation was used to perform path analysis between the response variable and the explanatory variables. The results reveal that competition contributes the most to changes in H-D ratio, followed by site index, topography and climate variables. The H-D ratio is positively affected by competition (DBH dominance and number of neighbors), site index, and May to September precipitation, but negatively affected by elevation. The results of path analysis indicate that the effects of elevation and May to September precipitation on H-D ratio can be mediated by site index. Although we sampled across broad climatic gradients, the effects of climate on H-D ratio were not as large as expected. In conclusion, competition is the primary driver for the variation in H-D ratio of Engelmann spruce, but the influence of environmental conditions including site quality, topography and climate on tree H-D ratio cannot be ignored. When designing management treatments for Engelmann spruce forests, we need to fully consider the potential effects of stand characteristics and environmental factors on tree stability.
摘要：
Marginal lands, such as those with saline soils, have potential as alternative resources for cultivating dedicated biomass crops used in the production of renewable energy and chemicals. Optimum utilization of marginal lands can not only alleviate the competition for arable land use with primary food crops, but also contribute to bioenergy products and soil improvement. Miscanthus sacchariflorus and M. lutarioriparius are prominent perennial plants suitable for sustainable bioenergy production in saline soils. However, their responses to salt stress remain largely unexplored. In this study, we utilized 318 genotypes of M. sacchariflorus and M. lutarioriparius to assess their salt tolerance levels under 150 mM NaCl using 14 traits, and subsequently established a mini-core elite collection for salt tolerance. Our results revealed substantial variation in salt tolerance among the evaluated genotypes. Salt-tolerant genotypes exhibited significantly lower Na+ content, and K+ content was positively correlated with Na+ content. Interestingly, a few genotypes with higher Na+ levels in shoots showed improved shoot growth characteristics. This observation suggests that M. sacchariflorus and M. lutarioriparius adapt to salt stress by regulating ion homeostasis, primarily through enhanced K+ uptake, shoot Na+ exclusion, and Na+ sequestration in shoot vacuoles. To evaluate salt tolerance comprehensively, we developed an assessment value (D value) based on the membership function values of the 14 traits. We identified three highly salt-tolerant, 50 salt-tolerant, 127 moderately salt-tolerant, 117 salt-sensitive, and 21 highly salt-sensitive genotypes at the seedling stage by employing the D value. A mathematical evaluation model for salt tolerance was established for M. sacchariflorus and M. lutarioriparius at the seedling stage. Notably, the mini-core collection containing 64 genotypes developed using the Core Hunter algorithm effectively represented the overall variability of the entire collection. This mini-core collection serves as a valuable gene pool for future in-depth investigations of salt tolerance mechanisms in Miscanthus.
摘要：
Self-constructed water-in-oil emulsions can be stabilized by a natural pentacyclic triterpenoid, betulin. A higher betulin concentration (3%) results in smaller emulsion droplet sizes. Microscopy, confocal laser scanning microscopy and rheology indicate that the stabilizing mechanism is attributed to betulin crystals on the emulsion interface and within the continuous phase, thereby enabling excellent freeze/thaw and thermal stability. The betulin Pickering emulsion (1%) significantly increased betulin bioaccessibility (22.4%) compared to betulin alone (0.2%) and betulin-oil physical mixture (7.9%). A higher level of betulin at 3% leads to smaller emulsion particle size, potentially resulting in a greater surface area. This, in return, promotes a higher release of free fatty acids (FFA), contributing to the release and solubilization of betulin from emulsions. Additionally, it leads to the formation of micelles, further increasing betulin bioaccessibility (29.3%). This study demonstrates Pickering emulsions solely stabilized by phytochemical betulin provides an innovative way to improve its bioaccessibility.
摘要：
Hydrochar serves not only as a fuel source but also as a versatile carbon material that has found extensive application across various domains. The application performance of hydrochar, e.g., energy recovery and carbon stability, is substantially influenced by its mass yield, higher heating value (HHV), and compositions (C, H, O, N, S, and ash), so the prediction and engineering of these properties is promising. In this study, two machine learning algorithms, namely gradient boosting regression (GBR) and random forest (RF), were used to predict the hydrochar properties mentioned above. The GBR models (with test regression coefficient (R2) values of 0.87-0.98 for single-target prediction and average test R2 of 0.93 for multi-target prediction) exhibited superior predictive capabilities to the RF models (with test R2 of 0.78-0.97 for single-target and average test R2 of 0.90 for multi-target prediction). The interpretation of ML models revealed the importance ranking of features for all targets. Then, engineering hydrochar was carried out through three different optimizations to the as-built multi target prediction model: i) optimizations of HTC conditions for given biomass samples; ii) optimization of biomass mixture recipes; iii) simultaneous optimization of both biomass mixing recipes and HTC conditions.
