58 research outputs found

    Literature review and experimental investigation of heat pipes

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    Tests on heat pipes determine operational limits, external boundary conditions, noncondensable gas effects, startup behavior, and geometric configurations. Experiment consists of design, construction, and testing of an apparatus for measuring wick properties, conventional heat pipes and coplanar heat pipes

    Quaternary glacial history of the Mediterranean mountains

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    Glacial and periglacial landforms are widespread in the mountains of the Mediterranean region. The evidence for glacial and periglacial activity has been studied for over 120 years and it is possible to identify three phases of development in this area of research. First, a pioneer phase characterized by initial descriptive observations of glacial landforms; second, a mapping phase whereby the detailed distribution of glacial landforms and sediments have been depicted on geomorphological maps; and, third, an advanced phase characterized by detailed understanding of the geochronology of glacial sequences using radiometric dating alongside detailed sedimentological and stratigraphical analyses. It is only relatively recently that studies of glaciated mountain terrains in the Mediterranean region have reached an advanced phase and it is now clear from radiometric dating programmes that the Mediterranean mountains have been glaciated during multiple glacial cycles. The most extensive phases of glaciation appear to have occurred during the Middle Pleistocene. This represents a major shift from earlier work whereby many glacial sequences were assumed to have formed during the last cold stage. Glacial and periglacial deposits from multiple Quaternary cold stages constitute a valuable palaeoclimatic record. This is especially so in the Mediterranean mountains, since mountain glaciers in this latitudinal zone would have been particularly sensitive to changes in the global climate system. © 2006 Edward Arnold (Publishers) Ltd

    Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)

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    Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem
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