995 research outputs found
A Programming Language for Web Service Development
There is now widespread acceptance of Web services and service-oriented architectures. But despite the agreement on key Web services standards there remain many challenges. Programming environments based on WSDL support go some way to facilitating Web service development. However Web services fundamentally rely on XML and Schema, not on contemporary programming language type systems such as those of Java or .NET. Moreover, Web services are based on a messaging paradigm and hence bring forward the traditional problems of messaging systems including concurrency control and message correlation. It is easy to write simple synchronous Web services using traditional programming languages; however more realistic scenarios are surprisingly difficult to implement. To alleviate these issues we propose a programming language which directly supports Web service development. The language leverages XQuery for native XML processing, supports implicit message correlation and has high level join calculus-style concurrency control. We illustrate the features of the language through a motivating example
The growth and economic development of the drug industry in the United States
Thesis (M.B.A.)--Boston University This item was digitized by the Internet Archive
Mid-infrared light emission > 3 µm wavelength from tensile strained GeSn microdisks
GeSn alloys with Sn contents of 8.4 % and 10.7 % are grown pseudomorphically on Ge buffers on Si (001) substrates. The alloys as-grown are compressively strained, and therefore indirect bandgap. Undercut GeSn on Ge microdisk structures are fabricated and strained by silicon nitride stressor layers, which leads to tensile strain in the alloys, and direct bandgap photoluminescence in the 3–5 µm gas sensing window of the electromagnetic spectrum. The use of pseudomorphic layers and external stress mitigates the need for plastic deformation to obtain direct bandgap alloys. It is demonstrated, that the optically pumped light emission overlaps with the methane absorption lines, suggesting that GeSn alloys are well suited for mid-infrared integrated gas sensors on Si chips
Primary and albedo solar energy sources for high altitude persistent air vehicle operation
A new class of the all electric airship to globally transport both passengers and freight using a 'feeder-cruiser' concept, and powered by renewable electric energy, is considered. Specific focus is given to photo-electric harvesting as the primary energy source and the associated hydrogen-based energy storage systems. Furthermore, it is shown that the total PV output may be significantly increased by utilising cloud albedo effects. Appropriate power architectures and energy audits required for life support, and the propulsion and ancillary loads to support the continuous daily operation of the primary airship (cruiser) at stratospheric altitudes (circa 18 km), are also considered. The presented solution is substantially different from those of conventional aircraft due to the airship size and the inherent requirement to harvest and store sufficient energy during "daylight" operation, when subject to varying seasonal conditions and latitudes, to ensure its safe and continued operation during the corresponding varying "dark hours". This is particularly apparent when the sizing of the proposed electrolyser is considered, as its size and mass increase nonlinearly with decreasing day-night duty. As such, a Unitized Regenerative Fuel Cell is proposed. For the first time the study also discusses the potential benefits of integrating the photo-voltaic cells into airship canopy structures utilising TENSAIRITY®-based elements in order to eliminate the requirements for separate inter-PV array wiring and the transport of low pressure hydrogen between fuel cells
Infra-red imaging of bulk water and water-solid interfaces under stable and metastable conditions.
International audienceSuperheated water has been studied by infrared spectroscopy to examine whether the special ability of liquid water to undergo such metastable state corresponds to the development of peculiar inter-molecular networking under tension. As the best technique to superheat water is to trap the liquid inside micro-cavities in solids (the so-called ―fluid inclusions‖), the role of the water-solid interfaces to stabilize the adjoining liquid is also explored with the same infra-red micro-spectroscopy tool. The key signal is the intra- molecular OH stretching band, sensitive to the networking in the probed material. The sample of choice is liquid water occluded inside quartz cavity of micrometric size, synthetized in laboratory from pure quartz and milli-Q water. The stretching band of the superheated water shows no significant spectral difference with that of a bulk ―normal‖ water, which means that the molecular properties of the superheating liquid is quite similar to those of the stable bulk liquid. Liquid water is readily ―superheatable‖ but retains its ―normality‖ under these special conditions. Additionally, this result establishes a firm ground to justify that the properties of the former are predicted extrapolating the usual (though empirical) equation of state of the latter. The infra-red signals of the water-solid interfaces are more complex. The water-solid interfaces blue-shift the signal, affecting differently the three sub-bands of the OH-stretching. This effect was unexpected since the micro-IR spectroscopy probes volume beyond of what is classicaly assigned for the interfacial properties. In addition, the interfacial signature is clearer under superheating than with the saturation conditions, which offers an interesting (and unexpected) way to interpret the special stability of the occluded metastable water. These encouraging results give confidence on the potentialities of the high-resolution micro-spectroscopy to get insights into the molecular basis of macroscopic properties
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