Three‐dimensional Structural Analysis Approach for Aging Composite Solid Propellant Grains

The viscoelastic aging behavior of composite solid propellant grains is studied by a three‐dimensional thermoviscoelastic constitutive model with aging evolution, in which the crosslinking degree is taken as an aging variable. The resulting viscoelastic constitutive equations are numerically discretized into incremental form by integration algorithms, and the stress‐updating method is presented according to incremental law. Subsequently, the Abaqus‐based user material subroutine and its structural analysis module are constructed and validated through typical examples. Studies show that the results of structural analysis have high accuracy and are in well agreement with each other. The designed analysis module presents an effective aging‐mechanical analysis platform for further lifespan estimation of solid rocket motors.     

A new vinylpyranoanthocyanin pigment occurring in aged red wine

A new pyranoanthocyanin–vinylphenol pigment was detected in an aged Port red wine. The UV–Vis spectrum of this pigment was found to have a λ_max of 538 nm that is bathochromically shifted from that of original anthocyanins, exhibiting a more purple hue in acidic solution. This newly formed pigment was synthesized in model solution through the reaction between malvidin 3-O-glucoside–pyruvic acid adduct and vinylphenol and its structure was assigned by NMR and mass spectrometry. This pigment is reported herein for the first time.     

电动缸伺服控制系统老化试验

针对自主研发的一款电动缸产品,用PLC及伺服驱动器进行了老化运行试验。在满足负载指标的基础上,实现高、低速往复的三轴运动,考核电动缸的负载能力、噪声水平、定位能力和可靠性。试验结果表明,该电动缸能够满足负载、稳定性和噪声的性能要求。     

老练条件的变化对铝电解电容器质量的影响

铝电解电容器的老练直接影响产品的质量。老练条件的变化对铝电解电容器的电容量、漏电流有一定的影响。在额定老练电压、＋ ９０℃５ｈ 条件下老练， 能更好地改善产品质量， 提高产品合格率。采用脉冲老练可以缩短老练时间， 但漏电流回升速度快     

冰淇淋生产中老化条件的确定

冰淇淋生产中老化条件的确定是冰淇淋质量好坏的重要因素之一。根据冰淇淋的实际生产配方、加工工艺与条件，测定料液在老化时粘度的增长情况。通过凝冻操作鉴定冰淇淋质量，最终确定料液所需老化时间。     

Film Thickness of Mechanically Worked Lubricating Grease at Very Low Speeds

Several different types of commercially available greases, aged in a roll stability tester, have been tested in a ball-on-disc machine where the film thickness was measured using the interferometry method. The grease film thickness at very low speed is thicker than the base oil film thickness due to the contribution of the thickener in this regime, which practically vanishes at higher speeds. The (mechanical) aging process reduces the thickener material, decreasing the grease film thickness at very low speeds (entrainment speed less than 0.01 m/s) with aging time, whereas no significant difference was found at higher speeds where the grease film thickness still approached the calculated base oil film thickness.     

Surface potential measurement of aged Li-ion batteries using Kelvin probe microscopy

In lithium-ion batteries, several electrical and physical parameters are responsible for the degradation of the electrode materials. Here the application of Kelvin probe microscopy (KPM) is demonstrated to measure the charge sustaining capability of the LiFePO₄ cathode under aged and unaged conditions. The aged sample shows lower surface potential than the unaged sample, which can be attributed to changes in physical and chemical properties including particle size, phase of the surface layer and nanocrystalline deposits.     

A STUDY ON KINETICS OF AGING OF PAVING ASPHALT

In this paper the aging processes of two penetration-grade paving asphalt which conform to the standard of Esson Company have been studied by rotation thin film oven (RTFO). The first order aging kinetic model has been established and some kinetics parameters were calculated. The relationship between pavement properties of asphalt and aging course was revealed. The intervention of oxygen in high temperature caused oxidation reactions, which changed the composition and structure of asphalt, the aging resistant performance of asphalt was weak, and the service performance went to bad.     

Health benefits of improving air quality in the rapidly aging Korean society

Korea is experiencing an extraordinarily rapid demographic transition. We investigated the short-term association between air pollution and mortality and assessed the impact of improved air quality on mortality in a rapidly aging city, Seoul, Korea.The generalized additive model (GAM) was used to estimate the relative risks (RR) of mortality associated with changes in air pollution. The time trends, seasonal variations, day of the week effects, and weather effects were controlled in the models. To estimate the health benefits, we used the US Environmental Protection Agency's BenMAP.For people 0–64 years of age, elderly people (65+ years), and all age groups, an increase of 10 μg/m³ in PM₁₀ was associated with increases in daily death counts of 0.27% (95% CI: 0.04–0.50), 0.45% (95% CI: 0.27–0.64), and 0.37% (95% CI: 0.23–0.52), respectively. For ages 0–64 years, elderly people, and all age groups, a 10 ppb increase in 1-hour maximum ozone concentration resulted in an increased risk of daily death counts of 0.28% (95% CI: − 0.19–0.74), 0.96% (95% CI: 0.46–1.47), and 0.81% (95% CI: 0.35–1.26), respectively.For elderly people, it was estimated that the health benefits of attaining the World Health Organization's (WHO) air quality guidelines (AQGs) for PM₁₀ (24-hour average 50 μg/m³) would suggest an annual reduction of 964 (95% CI: 564–1366) premature deaths, and 329 (95% CI: 159–500) premature deaths could be prevented annually in 2015 from attaining the WHO's guidelines for ozone (8-hour average 100 μg/m³).The rapid increase of the elderly population has major consequences and implications for society and public health. This study showed that elderly people are at higher risk for the acute mortality effects of air pollution. Therefore, cleaner air will substantially contribute to improved public health in Seoul, given the growing concern about the adverse effects of air pollution for elderly people.