The ageing behaviour of electric double layer (EDLC) supercapacitors during over-temperature and overvoltage stresses is described. Specific experimental tests were carried out in order to reproduce, under laboratory controlled conditions, the above-mentioned stresses. The obtained results are discussed and interpreted to define indicators that distinguish between over-temperature and over-volt...

objective: optimal dentin bonding is not always obtained in clinical practice due to func-tional forces. these forces may provide stresses throughout the tooth and restorative sys-tem, which in turn may affect the adhesive bond. this experimental study evaluated the effect of load cycling on bond strength of self-etch systems. materials and methods: one third of the coronal portions of 48 intac...

Various tests have been done of the STIS using internal wavecals to measure thermal motion of the spectral format on the detectors. In most cases, the spectral format moves less than the speci cation not to exceed 0.2 pixels per hour. Primary causes of the motion are 1) changes to the thermal design dictated by the warmer Aft Shroud environment and 2) on-orbit power cycling of MAMA electronics ...

The rate of the triacylglycerol/fatty acid substrate cycle was measured in vivo in adipose tissue of virgin and lactating rats with pups removed. The rate decreased by 70% in adipose tissue of lactating rats and increased 9-fold on removal of the pups. Similar differences in cycling rate were seen in adipose tissue incubated in vitro in the presence of isoprenaline.

Simultaneous lipolysis and reesterification form the triacylglycerol/fatty acid (TAG/FA) cycle, a substrate cycle commonly used for thermogenesis. Its rate was measured in vivo by indirect calorimetry and continuous infusion of [2-(3)H]glycerol and [1-(14)C]palmitate, after injection of leptin or vehicle saline in rabbits. Leptin stimulated in vivo lipolysis from 9.66 +/- 0.62 to 14.78 +/- 0.93...

Two novel system configurations were proposed for oxy-fuel natural gas turbine systems with integrated steam reforming and CO2 capture and separation. The steam reforming heat is obtained from the available turbine exhaust heat, and the produced syngas is used as fuel with oxygen as the oxidizer. Internal combustion is used, which allows a very high heat input temperature. Moreover, the turbine...

This paper shows the capability of current spreadsheets to define, analyse and optimise models of systems and processes. Specifically, the Microsoft spreadsheet, Excel®, is used with its built-in solver, to analyse and to optimise systems and processes of medium complexity whose mathematical models are expressed by means of non-linear systems of equations. Two hydraulic and thermal engineering-...

Models that characterize the displacement instability of the thermally grown oxide (TGO) found in some thermal barrier systems are reviewed, consolidated and extended. It is demonstrated that the simulations are only consistent with the observations whenever the bond coat and TGO both undergo plastic deformation. The TGO yields at the peak temperature, during growth, while the bond coat yields ...

Prognostics is a process of assessing the extent of deviation or degradation of a product from its expected normal operating condition, and then, based on continuous monitoring, predicting the future reliability of the product. By being able to determine when a product will fail, procedures can be developed to provide advanced warning of failures, optimize maintenance, reduce life cycle costs, ...

This paper discusses the commonly accepted method for life-time prediction for power converters in traction. The method is based on junction temperature estimation and thermal cycles on a given duty cycle. The predicted numbers of thermal cycles are compared to the curves giving the number of cycles to failure versus temperature cycles. These curves are extrapolated from power cycling tests. Po...