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Formation of linear polyenes -(CH=CH)- during thermal dehydration of thin layers (9-20 μm) of poly(vinyl alcohol) containing phosphotungstic-acid and aluminum-chloride catalysts was investigated. It was found that the concentration of long-chain ( n ≥ 8) polyenes in films containing phosphotungstic acid increased smoothly with increasing annealing time although the kinetics of the dehydration were independent of the film thickness. The polyene ( n ≥ 8) formation rate in films containing aluminum chloride dropped quickly with decreasing film thickness and increasing annealing time. As a result, long-chain polyenes practically did not form regardless of the annealing time for a film thickness of 11 μm. [ABSTRACT FROM AUTHOR]

Hot tearing has been an issue for many casting alloys, and much work has been devoted over the years to understanding the underlying mechanism, and to be able to mitigate it during casting. Unfortunately, the literature and therefore our understanding to date has been a bit muddled, as conflicting data and theories exist. In addition, many of the tests that have been developed to evaluate hot tearing have been qualitative in nature. Through the Light Metals Alliance, WPI's Metal Processing Institute and CANMET joined forces in 2006 to clarify our understanding of hot tearing and to enable us to control it during casting. This paper contains an overview of the authors' work; describes the quantitative test that was developed and discusses the processing variables that are needed to control and to mitigate hot tearing. [ABSTRACT FROM AUTHOR]

Abstract   We provide a convenient recipe for fabricating reliable superconducting microbolometers as acoustic phonon detectors with sub-nanosecond response, using image-reversal optical lithography and dc-magnetron sputtering, and our recipe requires no chemical or plasma etching. Our approach solves the traditional problem for granular aluminium bolometers of unreliable (i.e., non-Ohmic) electrical contacts by sequentially sputtering the granular aluminium film and then a palladium capping layer. We use dc calibration data, the method of Danilchenko et al. (Acta Phys. Pol. A 103(4):325, [2003]) and direct nanosecond-pulsed photoexcitation to obtain the microbolometer’s characteristic current, thermal conductance, characteristic relaxation time, and heat capacity. We also demonstrate the use of the deconvolution algorithm of Edwards et al. (J. Phys. E Sci. Instrum. 22:582, [1989]) to obtain the phonon flux in a heat pulse experiment with nanosecond resolution. [ABSTRACT FROM AUTHOR]