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Plants have evolved diverse secondary metabolites to counteract biotic stress. Volatile organic compounds (VOCs) are released upon herbivore attack or pathogen infection. Recent studies suggest that VOCs can act as signalling molecules in plant defence and induce resistance in distant organs and neighbouring plants. However, knowledge is lacking on the function of VOCs in biotrophic fungal infection on cereal plants.We analysed VOCs emitted by 13 ± 1‐day‐old barley plants (Hordeum vulgare L.) after mechanical wounding using passive absorbers and TD‐GC/MS. We investigated the effect of pure VOC and complex VOC mixtures released from wounded plants on the barley–powdery mildew interaction by pre‐exposure in a dynamic headspace connected to a powdery mildew susceptibility assay. Untargeted metabolomics and lipidomics were applied to investigate metabolic changes in sender and receiver barley plants.Green leaf volatiles (GLVs) dominated the volatile profile of wounded barley plants, with (Z)‐3‐hexenyl acetate (Z3HAC) as the most abundant compound. Barley volatiles emitted after mechanical wounding enhanced resistance in receiver plants towards fungal infection. We found volatile‐mediated modifications of the plant–pathogen interaction in a concentration‐dependent manner. Pre‐exposure with physiologically relevant concentrations of Z3HAC resulted in induced resistance, suggesting that this GLV is a key player in barley anti‐pathogen defence.The complex VOC mixture released from wounded barley and Z3HAC induced e.g. accumulation of chlorophyll, linolenic acid and linolenate‐conjugated lipids, as well as defence‐related secondary metabolites, such as hordatines in receiving plants. Barley VOCs hence induce a complex physiological response and disease resistance in receiver plants. [ABSTRACT FROM AUTHOR]

The objective of this paper is to present a procedure for high sheet temperature air channel testing of dual-track thermal seams for 0.75 mm thick polyvinyl chloride (PVC) geomembranes. This objective is accomplished by developing relationships between seam peel strength and seam burst pressure for sheet temperatures ranging from 46.7°C to 62.8°C during field air channel testing. This paper extends the original relationships presented by Thomas et al. and Stark et al., which extend only to 46.7°C, because a sheet temperature greater than 46.7°C is frequently encountered during hot summer months. The original relationship is extended to 62.8°C using the Arrhenius model, and a polynomial equation is presented that can be used to convert the sheet temperature during field air channel testing to the air channel pressure required to ensure that the specified seam peel strength of 2.6 N/mm is met or exceeded. Thus the proposed relationship and equation allow the seam peel strength to be verified by field air channel testing without conducting destructive tests. [ABSTRACT FROM AUTHOR]

This paper describes a final cover slope failure at a municipal solid waste containment facility. The lessons learned from this case history include: (i) slope stability analyses should be conducted whenever field conditions differ from initial design assumptions, such as a steeper slope and different geosynthetics; (ii) published values of interface strength/friction angle should not be used for final design, instead site-specific interface testing should be used; (iii) final cover slope angle should not exceed the lowest geosynthetic interface strength in the cover system to prevent tension in the geosynthetics and/or progressive slope failure of the slope; and (v) designers should resist the temptation to utilise a pre-existing final cover design without performing the necessary field reconnaissance, interface testing, analysis, and design for the new site. [ABSTRACT FROM AUTHOR]