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[Display omitted] • Differences on aroma profiles between Fujian and Yunnan white teas were revealed. • 28 Chiral free and glycosidically bound volatiles were identified and compared. • Linalool and α-terpineol showed the opposite major configurations in two white teas. • Glycosidically bound linalool oxides were directly quantified for the first time. • Fujian and Yunnan white teas could be distinguished based on nine key compounds. The Fujian and Yunnan provinces in China are the most representative origins of white tea. However, the key differences in the chemical constituents of the two white teas have rarely been revealed. In this study, a comprehensive comparison of the aroma profiles, chiral volatiles, and glycosidically bound volatiles (GBVs) in Fujian and Yunnan white teas was performed, and 174 volatiles and 28 enantiomers, including 22 volatiles and six GBVs, were identified. Linalool, linalyl-β-primeveroside (LinPrim), and α-terpineol presented the opposite dominant configurations in Fujian and Yunnan white teas, and the chiral GBVs were firstly quantified with significant differences in the contents of R -LinPrim and β- d -glucopyranosides of (2 R , 5 R)-linalool oxide A and (2 R , 5 S)-linalool oxide B. Moreover, discrimination functions for Fujian and Yunnan white teas were created using nine key variables with excellent reliability and efficiency. These results provide a new method for objectively distinguishing authentic white teas according to geographical origin. [ABSTRACT FROM AUTHOR]

For drag and heat flux reduction, many strategies equipped with jets have got lots of attentions recently. However, the establishment process of jet flow still remains unclear. In this investigation, an in-house code was developed to simulate the establishment process of spiked lateral jet flow and to uncover flow mechanisms. Firstly, code verification and validation were performed. Then the establishment process of spiked lateral jet in hypersonic flows is thoroughly investigated. Besides, some factors influencing the establishment process of spiked lateral jet are also explored. The results showed that the establishment process of spiked lateral jet in hypersonic flows is a strong transient process and contains complex flow phenomena. During the whole process, the aerodynamic drag firstly drops and then rises accompanying by fluctuation to a stable value. Increasing the lateral jet pressure would lead to severer interaction between the lateral jet and blunt body resulting in more dramatic fluctuation of aerodynamic drag. Besides, for fixed lateral jet pressure, longer spike is recommended. The transient flow structure is highly dominated by the lateral jet location and proper lateral jet location can decrease the fluctuation of aerodynamic drag during the establishment process of spiked lateral jet in hypersonic flows. [ABSTRACT FROM AUTHOR]

• Economic Policy Uncertainty (EPU) affects the volume and composition of fund flows to the US. • Elevated EPU increases equity fund flows and Treasury flows into the US in the medium-term. • Fund flows to the US are more sensitive to US EPU compared to global EPU. In this letter, we examine the impact of economic policy uncertainty (EPU) on aggregate fund flows to the United States (US). US and global EPU are strongly and negatively related to equity fund flows in the short run. However, initial declines reverse over the medium term and have a positive cumulative effect on equity allocations to the US. EPU is positively related to Treasury flows in the short run that indicates managers reallocate their portfolios following uncertainty shocks. Indeed, we show a negative relation between equity fund flows and Treasury flows. Furthermore, both types of fund flows are more sensitive to US EPU compared to global EPU. [ABSTRACT FROM AUTHOR]

A pressure control method that incorporates parameter adaptation has been devised for the pressure control system of pintle solid rocket motors, which exhibit notable nonlinearities and uncertainties in parameters. Firstly, the mathematical relationship between pressure and pintle displacement is derived using the zero-dimensional interior ballistic model., and the state space equation is deduced by incorporating the dynamics of motor inertia load. Secondly, by capitalizing on the robustness of robust control, the parameter identification capabilities of adaptive control, and the rigor of Lyapunov stability theory, the proposed approach enables precise control of the pintle position while effectively addressing uncertainties, thereby enhancing the overall performance and stability of the system. Finally, the aforementioned theoretical framework has been validated through rigorous numerical simulations. The findings demonstrate a notable enhancement in the pressure response speed of the adaptive robust controller, with improvements of 10.01 % and 13.16 %, 0.03 % and 1.54 %, 0.06 % and 22.39 % in different orders of magnitude of free volume as compared to the robust controller and PID controller, respectively. Moreover, it is evident that the adaptive robust controller relies on the accuracy of the model. The applied controller demonstrates notable advantages in terms of stability, robustness, and accuracy, thereby substantially enhancing the overall performance of the pressure control system. • The state space equation for the pressure of the pintle solid rocket motors is derived. • The pressure dynamics equation and the motor inertial load equation are combined. • An adaptive robust controller with respect to pressure is designed. • The controller response laws for various free volumes, pressure index and characteristic velocity are obtained. • The adaptive robust controller exhibits a higher dependence on model accuracy is observed. [ABSTRACT FROM AUTHOR]

We examine the channel relationship between cultural dimensions, public expenditure on education, and country level PISA test scores. We test the hypotheses that cultural dimensions impact aggregate public expenditure on education and higher expenditure improves PISA results. We find a causal relationship between measures of culture and expenditure on education. In particular, we document the negative impact of power distance and masculinity on education expenditure. In contrast, individualism and long-term orientation positively impact public expenditure. In addition, we find a strong positive association between public expenditure on education and PISA scores at the country level. These findings are robust and consistent for all PISA test types. Our research findings shed light on the important role of cultural dimensions on education expenditure and inter-country differences in PISA performance. [ABSTRACT FROM AUTHOR]

In order to gain insight into aluminum agglomeration behaviors and agglomeration processes, the aluminized fuel-rich propellants in solid fuel ramjet are investigated by using sampling method followed by scanning electron microscopy and laser scattering experimental technique on the small-scale combustion experimental system and connected-pipe experimental system. It is observed that the aluminum particles would break away from the burning surface after agglomeration, and interpocket agglomeration occurred. Under different ambient pressures, the microstructure of the combustion products and the aggregation behavior of aluminum particles are further analyzed. Based on the classical pocket theory and particle size analysis experiments, a new agglomeration size prediction model is established. It can be used to predict the agglomeration size on the burning surface. Compared with the empirical model and the typical pocket model, this model is in good agreement with the experimental results. A connected-pipe experimental system for solid fuel ramjet is established. The effects of inlet air temperatures on the combustion performance of ramjet, the microstructure and agglomeration size are studied. With the increase of inlet air temperature, the agglomeration size decreases, the pressure, temperature and thrust in the combustion chamber increase, which makes the propellant burn more fully. The characteristic velocity, specific impulse and combustion efficiency of the solid fuel ramjet increase. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Es-GC×GC-TOFMS approach to separate chiral volatiles in tea was established. • Volatile enantiomers in Wuyi rock teas from four cultivars were firstly quantitated. • Limits of quantitation of linalool oxides A−B in teas were as low as 0.2 pg/mL. • R -α-Ionone, S -(E)-nerolidol etc. were the potential markers to distinguish cultivar. • 7 Volatile enantiomers were identified as aroma-active compounds in Wuyi rock teas. Chiral volatiles play important roles in the formation of aroma quality of foods. To date, enantiomeric characteristics of chiral volatiles in Wuyi rock tea (WRT) and their aroma contributions are still unclear. In this study, an efficient enantioselective comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (Es-GC × GC-TOFMS) approach to separate and precisely quantitate 24 pairs of chiral volatiles in WRTs was established, and the enantiomeric distribution and aroma contribution of chiral volatiles among WRTs from four representative cultivars were investigated. Enantiomeric ratio (ER) of R -α-ionone (80%) in Dahongpao (DHP), ER of S -α-terpineol (57%) in Jinfo (JF), ERs of R -γ-heptanolactone (69%), S -γ-nonanolactone (55%), (2 R , 5 S)-theaspirane B (91%), concentration of S -(E)-nerolidol (313.37 ng/mL) in Rougui (RG) and concentration of R -α-ionone (33.01 ng/mL) in Shuixian (SX) were unique from other types of WRTs, which were considered as the potential chemical markers to distinguish WRT cultivars. The OAV assessment determined 7 volatile enantiomers as the aroma-active compounds, especially R -α-ionone and R -δ-octanolactone in SX, as well as S -(E)-nerolidol and (1 R , 2 R)-methyl jasmonate in RG contribute much to aroma formation of the corresponding WRTs. The above results provide scientific references for discrimination of tea cultivars and directed improvement of the aroma quality of WRT. [ABSTRACT FROM AUTHOR]