Effect of facility variation on the acoustic characteristics of three single stream nozzles

The characteristics of the jet noise produced by three single stream nozzles were investigated statistically at the NASA-Lewis Research Center outdoor jet acoustic facility. The nozzles consisted of a 7.6 cm diameter convergent conical, a 10.2 cm diameter convergent conical and an 8-lobe daisy nozzle with 7.6 cm equivalent diameter flow area. The same nozzles were tested previously at cold flow conditions in other facilities such as the Royal Aircraft Establishment (RAE) 7.3 m acoustic wind tunnel. The acoustic experiments at NASA covered pressure ratios from 1.4 to 2.5 at total temperatures of 811 K and ambient. The data obtained with four different microphone arrays are compared. The results are also compared with data taken at the RAE facility and with a NASA prediction procedure

Hydrogen bonds and asymmetrical heat diffusion in a-Helices. A Computational Analysis

In this work, we report the heat rectifying capability of a-helices. Using molecular dynamics simulations we show an increased thermal diffusivity in the C-Terminal to N-Terminal direction of propagation. The origin of this effect seems to be a function of the particular orientation of the hydrogen bonds stabilizing these a-helices. Our results may be relevant for the design of thermal rectification devices for materials science and lend support to the role of normal length hydrogen bonds in the asymmetrical energy flow in proteins

Using tactical and operational factors to assess strategic alignment: an SME study

The strategic use of Information Technology (IT), better known as strategic alignment, has significantly increased, as a result of the strong dependence of organisational activity on Information Systems (IS) and their related technologies. Strategic alignment is considered as a key element to improve performance on organisations, enhance efficiency and allow organisations to be more competitive in their respective industry. One of the first steps towards achieving strategic alignment is to have adequate means to measure it. Current assessment approaches, though, are mainly focused at the strategic level but provide little insight at tactical and operational levels, which are recognized as important areas for achieving strategic alignment. Furthermore, most of the existing approaches are tested in large organisations and there is little research on assessing the effectiveness of these approaches for Small and Medium Enterprises (SMEs). This paper proposes an alternative instrument that rather than focusing only at the strategic level it aims to have a better understanding by measuring alignment at tactical and operational levels. Finally this paper presents the findings of applying this instrument on an SME