Land surface temperature (LST) is an important parameter to evaluate environmental changes. In this paper, time series analysis was conducted to estimate the interannual variations in global LST from 2001 to 2016 based on moderate resolution imaging spectroradiometer (MODIS) LST, and normalized difference vegetation index (NDVI) products and fine particulate matter (PM2.5) data from the Atmospheric Composition Analysis Group. The results showed that LST, seasonally integrated normalized difference vegetation index (SINDVI), and PM2.5 increased by 0.17 K, 0.04, and 1.02 μg/m3 in the period of 2001–2016, respectively. During the past 16 years, LST showed an increasing trend in most areas, with two peaks of 1.58 K and 1.85 K at 72°N and 48°S, respectively. Marked warming also appeared in the Arctic. On the contrary, remarkable decrease in LST occurred in Antarctic. In most parts of the world, LST was affected by the variation in vegetation cover and air pollutant, which can be detected by the satellite. In the Northern Hemisphere, positive relations between SINDVI and LST were found; however, in the Southern Hemisphere, negative correlations were detected. The impact of PM2.5 on LST was more complex. On the whole, LST increased with a small increase in PM2.5 concentrations but decreased with a marked increase in PM2.5. The study provides insights on the complex relationship between vegetation cover, air pollution, and land surface temperature.

Trapping parameters can be considered as one of the important attributes to describe polymeric materials. In the present paper, a more accurate charge dynamics model has been developed, which takes account of charge dynamics in both volts-on and off stage into simulation. By fitting with measured charge data with the highest R-square value, trapping parameters together with injection barrier of both normal and aged low-density polyethylene (LDPE) samples were estimated using the improved model. The results show that, after long-term ageing process, the injection barriers of both electrons and holes is lowered, overall trap depth is shallower and trap density becomes much greater. Additionally, the changes in parameters for electrons are more sensitive than those of holes after ageing.

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In this study, cardanol, a natural phenol, has been applied to toughen phenolic foam by bisphenol modification. In order to verify the occurrence of Friedel-Craft alkylation between cardanol and phenol on the side chain, FTIR, and NMR had been used to characterize the bisphenol successfully. With the introduction of cardanol, the viscosity of prepolymers increased. The SEM results demonstrated that the some cells with increasingly large size existed, when the dosage of cardanol increased. With respect to the mechanical properties, phenolic foams modified by 10 wt % cardanol increased by 22% in flexural strength and 28% in bending modulus compared to pure phenolic foams, which indicates that the incorporation of cardanol does improve the toughness of phenolic foams. In addition, the effects of different dosage of cardanol on the apparent density and thermal stability of phenolic foams were investigated.

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The cell distribution of open-celled phenolic foams with different contents of epoxy (0 wt %, 5 wt %, 10 wt %, 15 wt %). Abstract: A series of micro-porous phenolic open-cell sound absorbent foams reinforced by epoxy resin were fabricated by physical foaming method. The compound emulsifiers consisting of anionic and non-ionic surfactants were physical blended at high speed with modified resols, foaming agent and mixed acid curing agent. The viscosity, surface tension, gel permeation chromatography (GPC) were characterized. Fabricated foams were characterized for pore size distribution, water absorption, sound absorption, mechanical and thermal properties. Surface tension and porosity analysis demonstrated that anionic surfactant, sodium dodecyl sulfonate (SDS) promoted the formation of homogeneous micro-pores. And the open cell porosity reached up to 90%. The open-celled pore structure and cell size distribution revealed by Scanning electron microscopy (SEM) demonstrated that more homogeneous and smaller open cells existed with increasing dosage of epoxy. And the sound absorption properties were increased significantly when adding the epoxy resin, even can reached about 95%. The micro-pore and cell-distribution controlled by the content of epoxy resin and the ratio of SDS/tween-80, greatly improved the mechanical strengths of phenol-formaldehyde resin (PF).

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