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-This article presents the results of experimental and finite element analysis of mistuned free vibration of bladed disk models. Blade-to-blade variations of bladed disk assemblies result in local zoning of vibration modes as well as amplitude magnifications, which primarily reduces the high cycle fatigue life of turbomachines rotors. Geometrical mistuning and other types of mistuning were investigated to determine the level of these mode localization effects depending on various vibration parameters of a bladed disk. The main objective was to determine the order of mistuned blades in the bladed disk, leading to the largest and smallest change in vibration characteristics. Obtaining dependencies are important for following researches in this field, in particular, for calculating the fatigue life of the real bladed disks.

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A phytochemical study on fruits of Melia dubia Cav. collected in Nghe An province led to the isolation of three secondary metabolites, including 21α-O-methylmelianodiol (1), 21β-O-methylmelianodiol (2) and (21S,23R,24R)-21,23-epoxy-24-hydroxy-21β-methoxytirucalla-7,25-dien-3-one (3). The chemical structures of these compounds were determined on the basis of 1D, 2D NMR, UV, IR and MS analytical results and comparison with reported data. All three compounds (1–3) were isolated from this plant for the first time.