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The moisture sorption isotherm of wheat gluten/epoxydized sesame or sunflower oil resin was determined at 25, 40, and 55°C. The resin was prepared by cross-linking epoxydized oil and wheat gluten using 1, 2, and 3% zinc chloride as the catalyst. The experiment was carried out over 0.1–0.9 water activity (a w) range using gravimetric sorption analyzer (Q 2000, TA Instruments, New Castle, PA, USA). The resin isotherms were found to be type III shape where the equilibrium moisture content (EMC) was higher at lower temperatures. The EMC of gluten epoxy resin was dependent on the degree of cross-linking because more cross-linking decreased EMC. The Guggenheim Anderson-de Boer (GAB) parameters support the theory of the free volume as it relates to monolayer absorption. This could be attributed to the decrease in the number of water binding sites due to the development of dense areas during cross-linking and increase in the free volume. The GAB and Brunauer–Emmett–Teller were found to be suitable for predicting the water sorption isotherm for gluten protein resin because it provided low root mean square error. The heat of sorption based on the Clausius–Clapeyron equation (qst) increased with decrease in moisture content. [ABSTRACT FROM AUTHOR]

Global urbanization drastically reshapes the land–atmosphere interactions, biogeochemical cycles, and ecosystems in the integrated earth system. Urban trees are used extensively for providing desirable ecosystem services, especially to mitigate elevated thermal stress in cities. Urban trees differ markedly from their natural counterparts in the physiology due to their close interactions with anthropogenic stressors. Here we present the cooling capacity of urban trees in response to thermal extremes in cities of the contiguous United States. The cooling capacity is quantified as the surface cooling rate, which is expressed as the negative ratio of land surface temperature (LST) changes to fractional tree cover (FTC) changes, i.e., –ΔLST/ΔFTC. Results show that the surface cooling rate is dominated by plant transpiration up to 1.336 °C per percentage of FTC in heat waves; its temperature dependence remarkably resembles the thermodynamic liquid-water-vapor equilibrium. Urban trees also exert pseudo cooling effect in cold waves in contrast to the anthropogenic heat emission. The average surface cooling rate in cold waves is 0.022 °C per percentage of FTC, which is much smaller than that in heat waves (0.202 °C per percentage of FTC). The enhanced cooling capacity of urban trees will enable their provision of better ecosystem services to the urban environment for projected future increase of extreme heat. Unlabelled Image • The surface cooling rate of urban trees during heat and cold waves is quantified. • Temperature dependence of tree cooling resembles the phase equilibrium of water. • The cooling of urban trees is dominated by plant transpiration in heat waves. • The synthetic cooling of cities is regulated by anthropogenic heat in cold waves. • Urban trees are ahead of the global change responses than their rural counterparts. [ABSTRACT FROM AUTHOR]

Landfalling--tropical cyclone (TC) rainfall is an important element of inland flood hazards in the eastern United States. The projection of landfalling-TC rainfall under anthropogenic warming provides insight into future flood risks. This study examines the frequency of landfalling TCs and associated rainfall using the GFDL Forecast-Oriented Low Ocean Resolution (FLOR) climate model through comparisons with observed TC track and rainfall over the July--November 1979--2005 seasons. The projection of landfalling-TC frequency and rainfall under the representative concentration pathway (RCP) 4.5 scenario for the late twenty- first century is explored, including an assessment of the impacts of extratropical transition (ET). In most regions of the southeastern United States, competition between increased storm rain rate and decreased storm frequency dominates the change of annual TC rainfall, and rainfall from ET and non-ET storms. In the northeastern United States, a prominent feature is the striking increase of ET-storm frequency but with tropical characteristics (i.e., prior to the ET phase), a key element of increased rainfall. The storm-centered rainfall composite analyses show the greatest increase at a radius of a few hundred kilometers from the storm centers. Over both ocean and land, the increase of rainfall within 500 km from the storm center exceeds the Clausius--Clapeyron scaling for TC-phase storms. Similar results are found in the front-left quadrant ofET-phase storms. Future work involving explorations ofmultiplemodels (e.g., higher atmospheric resolution version of the FLOR model) for TC-rainfall projection is expected to add more robustness to projection results. [ABSTRACT FROM AUTHOR]

ABSTRACT The mean North American and world climates have warmed since the 19th century following the anthropogenic emission of large quantities of greenhouse gases. It has been suggested that this warming may increase the frequency or severity of droughts. We define a quantitative and objective aridity index that describes the precipitation forcing function of drought. Using the extensive historical database of precipitation records, we evaluate changes in the aridity in the 48 contiguous United States. The area-averaged mean fractional rate of change of aridity of 1218 sites in the period 1893-2013 was (−6.6 ± 0.4) × 10− 4 per year; the 48 contiguous United States became less arid. The rate of decrease of aridity was roughly consistent with expectations from the Clausius-Clapeyron relation and the rate of warming. The fractional rate of change of aridity was nearly uncorrelated with the aridity itself, but there were regional differences: many Western and coastal Southeastern sites showed increasing aridity, but regions of rapidly decreasing aridity were found in a band 85∘-100∘W and the Northeast. [ABSTRACT FROM AUTHOR]