Intersections of sequences of ideals generated by polynomials

AbstractWe present a method for determining the reduced Gröbner basis with respect to a given admissible term order of order type ω of the intersection ideal of an infinite sequence of polynomial ideals.As an application we discuss the Lagrange type interpolation on algebraic sets and the “approximation” of the ideal I of an algebraic set by zero dimensional ideals, whose affine Hilbert functions converge towards the affine Hilbert function of I

Development of a wood-fired cooking stove to incorporate a thermo-acoustic engine-generator unit

The provision of affordable electrical power in off-grid rural areas of developing countries is a major challenge but a vital element in the battle to reduce poverty. In response to this need, the SCORE project objective was to integrate a novel technology, thermo-acoustics, into a domestic cooking stove in order to produce an adequate level of electricity supply for families in developing countries whilst also providing efficient cooking. The unit is aimed at the majority of poorer families in developing countries that do not have access to electricity and have little hope of being connected to grid electricity in the near future. The electrical generation function is a vital driver in the adoption of low emissions stoves which significantly reduce health problems from smoke inhalation. This paper describes the design of the cooking part of the stove developed within the framework of the project. Within the wood burning stove, heat released by combustion is first transferred to a thermo-acoustic engine (TAE) to generate electricity, and then to the cooking part. The paper describes the development of the design and construction of the stove to meet the above objectives. This has been progressed through extensive testing of prototype stoves and also through modelling of the heat transfer within the combustion chamber and also for the cooking part of the stove The paper presents and compares the results from the test programme and heat transfer modelling and shows how the results are being used to achieve a stove design with an acceptable level of performance. It then concludes with a discussion of how this design might be produced in developing countries

FlashCam: A fully digital camera for CTA telescopes

The future Cherenkov Telescope Array (CTA) will consist of several tens of telescopes of different mirror sizes. CTA will provide next generation sensitivity to very high energy photons from few tens of GeV to >100 TeV. Several focal plane instrumentation options are currently being evaluated inside the CTA consortium. In this paper, the current status of the FlashCam prototyping project is described. FlashCam is based on a fully digital camera readout concept and features a clean separation between photon detector plane and signal digitization/triggering electronics.Comment: In Proceedings of the 2012 Heidelberg Symposium on High Energy Gamma-Ray Astronomy. All CTA contributions at arXiv:1211.184

Comparison of earthquake-triggered turbidites from the Saguenay (Eastern Canada) and Reloncavi (Chilean margin) Fjords: implications for paleoseismicity and sedimentology

International audienceHigh-resolution seismic profiles along with physical and sedimentological properties of sediment cores from the Saguenay (Eastern Canada) and Reloncavi (Chile) Fjords allowed the identification of several decimeter to meter-thick turbidites. In both fjords, the turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663 AD (M > 7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M ~ 8) and 1575 AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575 AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In the Saguenay Fjord, the earthquake-triggered turbidites are sometimes underlying a hyperpycnite associated with the rapid breaching and draining of a natural dam formed by earthquake-triggered landslides. Similar hyperpycnal floods were also recorded in historical and continental geological archives for the 1960 and 1575 AD Chilean subduction earthquakes, highlighting the risk of such flood events several weeks or months after main earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, this paper also emphasizes the sensitivity of fjords to record historic and pre-historic seismicity