Temperature influences the toxicity, behavioral, and physiology response of chlorfenapyr, fipronil, imidacloprid, and indoxacarb to Reticulitermes flaviceps

Han Hui,Liu Yu,Yang Shimeng,Xue Haozhe,Zhang Dayu,Xie Yongjian 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.2

A comprehensive understanding of the interaction between pesticides and climate change is critical to the safety of pesticide applications. Many insecticides are actually more toxic at higher temperatures. However, little is currently known about the effect of temperature on the toxicity of chemicals. In order to fill this knowledge gap and improve our understanding of the mechanisms of temperature effects, the present study investigated the toxic, physiological, and behavioral effects of four insecticides, chlorfenapyr, fipronil, imidacloprid, and indoxacarb, on subterranean termites, Reticulitermes flaviceps at different temperatures (24 to 32 ◦ C). The results show that the sensitivity of R. flaviceps to chrofenapyr (LC 50 = 8.67–152.49 mg/L), fipronil (LC 50 = 10.14–36.84 mg/L), imidacloprid (LC 50 = 184.27–326.47 mg/L) and indoxacarb (LC 50 = 12.23–46.23 mg/L) substantially increased when the temperature alters from 24 to 32 ◦ C. Additionally, the activities of three detoxification en zymes [glutathione S-transferases (GSTs), carboxylesterase (CarE), and cytochrome P450 (P450)] of R. flaviceps were also measured of four insecticide at various temperatures. Correlation analysis reveals that changes in GSTs CarE and P450 activities of R. flaviceps are closely related to their sensitivity to chlorfenapyr, fipronil, imida cloprid, and indoxacarb. Meanwhile, the speed of action (LT 50 value) of four insecticides is positively affected by temperature. In addition, intoxication, ataxia, and moribundity behaviors were observed in most concentrations and temperature combinations for chlorfenapyr, fipronil, and imidacloprid–exposed termite. The findings of our research emphasize that in the context of global climate change, the development and application of pesticides should consider the temperature dimension.

Analysis of the Climate inside Multi-span Plastic Greenhouses under Different Shade Strategies and Wind Regimes

Keshi He,Dayue Chen,Lijuan Sun,Zhenyu Huang,Zhenglu Liu 한국원예학회 2014 원예과학기술지 Vol.32 No.4

In this work, the effects of shade combination, shade height and wind regime on greenhouse climate were quantified. A two-dimensional (2-D) computational fluid dynamics (CFD) model was developed based on an 11-span plastic greenhouse in eastern China for wind almost normal to the greenhouse orientation. The model was first validated with air temperature profiles measured in a compartmentalized greenhouse cultivated with mature lettuce (Lactuca sativa L., ‘Yang Shan’). Next, the model was employed to investigate the effect of shade combinations on greenhouse microclimate patterns. Simulations showed similar airflow patterns in the greenhouse under different shade combinations. The temperature pattern was a consequence of convection and radiation transfer and was not significantly influenced by shade combination. The use of shade screens reduced air velocity by 0.02-0.20 m·s<SUP>-1</SUP>, lowered air temperature by 0.2-0.8℃ and raised the humidity level by 0.9-2.0% in the greenhouse. Moreover, it improved the interior climate homogeneity. The assessment of shade performance revealed that the external shade had good cooling and homogeneity performance and thus can be recommended. Furthermore, the effects of external shade height and wind regime on greenhouse climate parameters showed that external shade screens are suitable for installation within 1 m above roof level. They also demonstrated that, under external shade conditions, greenhouse temperature was reduced relative to unshaded conditions by 1.3℃ under a wind speed of 0.5 m·s<SUP>-1</SUP>, whereas it was reduced by merely 0.5℃ under a wind speed of 2.0 m·s<SUP>-1</SUP>. Therefore, external shading is more useful during periods of low wind speed.

Analysis of the Climate inside Multi-span Plastic Greenhouses under Different Shade Strategies and Wind Regimes

He, Keshi,Chen, Dayue,Sun, Lijuan,Huang, Zhenyu,Liu, Zhenglu Korean Society of Horticultural Science 2014 원예과학기술지 Vol.32 No.4

In this work, the effects of shade combination, shade height and wind regime on greenhouse climate were quantified. A two-dimensional (2-D) computational fluid dynamics (CFD) model was developed based on an 11-span plastic greenhouse in eastern China for wind almost normal to the greenhouse orientation. The model was first validated with air temperature profiles measured in a compartmentalized greenhouse cultivated with mature lettuce (Lactuca sativa L., 'Yang Shan'). Next, the model was employed to investigate the effect of shade combinations on greenhouse microclimate patterns. Simulations showed similar airflow patterns in the greenhouse under different shade combinations. The temperature pattern was a consequence of convection and radiation transfer and was not significantly influenced by shade combination. The use of shade screens reduced air velocity by $0.02-0.20m{\cdot}s^{-1}$, lowered air temperature by $0.2-0.8^{\circ}C$ and raised the humidity level by 0.9-2.0% in the greenhouse. Moreover, it improved the interior climate homogeneity. The assessment of shade performance revealed that the external shade had good cooling and homogeneity performance and thus can be recommended. Furthermore, the effects of external shade height and wind regime on greenhouse climate parameters showed that external shade screens are suitable for installation within 1 m above roof level. They also demonstrated that, under external shade conditions, greenhouse temperature was reduced relative to unshaded conditions by $1.3^{\circ}C$ under a wind speed of $0.5m{\cdot}s^{-1}$, whereas it was reduced by merely $0.5^{\circ}C$ under a wind speed of $2.0m{\cdot}s^{-1}$. Therefore, external shading is more useful during periods of low wind speed.

Multi-objective optimization modification of a tooth surface with minimum of flash temperature and vibration acceleration RMS

Xigui Wang,Yongmei Wang,Yixiang Liu,Xinbo Zhang,Dayu Zheng 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

The minimum of tooth surface flash temperature and vibration acceleration RMS design is proposed and analyzed. The tooth contact analysis (TCA) and the load tooth contact analysis (LTCA) method and multi-objective optimization are also detailed. Satisfying design variables in multiple physical quantities leads to the minimum of multi-objective optimization. Considering the tooth surface loading conditions are uniform or not, the optimal modification of the tooth surface for improving gear comprehensive characteristics under various load bearing conditions is improved. The tooth surface flash temperature and vibration acceleration root mean square (RMS) values in different transmission modes of marine ship power rear gears drive system are derived. This research considers the multi-objective optimization modifications of tooth surface, and its main purpose is to propose an approach to help design tooth corrections to simultaneously optimize several objective physical quantities.

Enhanced activity and hydrothermal stability of Rh-based three-way catalyst for emission control from motorcycles with the assistance of monoethanolamine

Li Lan,Jinfeng Wang,Shanhu Chen,Dacheng Li,Hongmei Li,Dayu Liu,Wei Wang,Yaoqiang Chen 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.71 No.-

In this work, an advanced Rh/CeO2–ZrO2 (Rh/CZ) three-way catalyst was synthesized with the assistanceof monoethanolamine. Compared with conventional Rh/CZ, the dispersion and oxidation state of Rhspecies, as well as the hydrothermal aging resistance are remarkably modified. That is, upon agingtreatment, conventional Rh/CZ undergoes severe agglomeration of Rh species and formation of largeamount of reduction-resistive RhO2, resulting in serious catalyst deactivation. Fortunately, after theintroduction of monoethanolamine, the sintering of Rh species and transformation into inactive RhO2upon aging are effectively suppressed. Consequently, improved reducibility and advanced three-waycatalytic activity are achieved for the modified catalyst.