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SummaryIn this paper, the adaptive back‐stepping controller is investigated for a class of strict‐feedback systems using the command filter technique. Adaptive laws are designed for updating the controller parameters when both the plant parameters and actuator‐failure parameters are unknown. Furthermore, the auxiliary dynamics is developed to deal with the input constraints. Closed‐loop stability and asymptotic‐state tracking are ensured. The method is applied to the longitudinal dynamics of a generic hypersonic aircraft in the presence of actuator faults and input constraints. Based on the parameter estimation, the command‐filtered adaptive back‐stepping control is presented. Simulation results on the control‐oriented model show that the proposed approach achieves good tracking performance. Copyright © 2015 John Wiley & Sons, Ltd.

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Higher crude‐oil prices, increases in energy imports, concerns about petroleum supplies, and greater recognition of environmental consequences of fossil fuels have spurred a search for alternative sources of fuel. In the aspect of choosing an appropriate source for a long‐term development, it is necessary to decide which is the most sustainable. This article describes a systematic method based on Analytical Hierarchical Process technique to compare biodiesel feedstock alternatives on technical, economical, and sustainable aspects throughout life cycles of biodiesel production. Five biodiesel feedstocks which are jatropha, algae, palm oil, rapeseed, and soybean are taken into consideration in a quantified evaluation. Among these alternatives and with a recommended scoring structure, biodiesel from algae is shown in the calculation results to be the highest ranking substitute for diesel fuel due to its overall better performance in the aspects of environment, economical, safety, raw material performance, and fuel performance. © 2009 American Institute of Chemical Engineers Environ Prog, 2009

The synthesis of the hexasaccharide fragment of the antitumor antibiotic landomycin A (1) (aka. NSC 639187) is described. The stereocontrolled introduction of key glycoside linkages relies on the combined application of glycosyl tetrazoles and phosphites to establish R and glycosidic linkages, respectively. Spectral comparison of landomycin A octaacetate (2) and hexasaccharide pentaacetate (3) serves to corroborate the assigned structure of 1 within the oligosaccharide domain.Deoxygenated oligosaccharides are ubiquitous among secondary metabolites, particularly within the genus streptomyces.

The new series of tellurium-containing trigonal bipyramidal clusters [Te2CrM2(CO)10]2- (M = Cr, 2a; Mo, 2b; W, 2c) has been synthesized from the ring closure reactions of the ring complexes [Te2Cr2M2(CO)18]2- (M = Cr, 1a; Mo, 1b; W, 1c) in refluxing acetone solutions. The mixed-metal ring complexes [Te2Cr2M2(CO)18]2- (M = Mo, 1b; M = W, 1c) can be obtained readily from the metal expansion reactions of the dichromium complex [Te{Cr(CO)5}2]2- with M(CO)6 (M = Mo, W) in MeCN. The ring complexes [Te2Cr2M2(CO)18]2- (M = Mo, 1b; W, 1c) each display a Te2M2 ring with each Te atom externally coordinated with one Cr(CO)5 group, while the new group 6-containing trigonal bipyramidal clusters [Te2CrM2(CO)10]2- (M = Cr, 2a; Mo, 2b; W, 2c) each consist of a CrM2 trigonal plane capped above and below by two tellurides. Complexes 1b−2c are fully characterized by IR, 125Te NMR spectroscopy, and single-crystal X-ray analysis. This paper describes a new methodology to the highly strained group 6 metal clusters [Te2CrM2(CO)10]2- (M = Cr, 2a; Mo, 2b; W, 2c) from the ring closure reactions of their corresponding ring complexes [Te2Cr2M2(CO)18]2- (M = Cr, 1a; Mo, 1b; W, 1c), and the interesting transformations and structural features of the new complexes 1b−2c are systematically studied as well.