Technological survey of tellurium and its compounds

Review includes data on the chemical and physical properties of tellurium, its oxides, and fluorides, pertinent to the process problem of handling fission product tellurium in fluoride form. The technology of tellurium handling in nonaqueous processing of nuclear fuels is also reviewed

Leaf phenolics and seaweed tannins : analysis, enzymatic oxidation and non-covalent protein binding

Upon extraction of proteins from sugar beet leaves (Beta vulgaris L.) and oarweed (Laminaria digitata) for animal food and feed purposes, endogenous phenolics and proteins can interact with each other, which might affect the protein’s applicability. Sugar beet leaf proteins might become covalently modified by phenolics through polyphenol oxidase (PPO) activity. Oligomeric phenolics from seaweed (so-called phlorotannins (PhT)) might bind non-covalently to protein. The first aim of this thesis was to study factors involved in protein modification by phenolics. The second aim was to investigate the effect of PhT supplementation to feed on in vitro ruminal fermentation. Besides PPO activity and the amount of low molecular weight phenolic substrates present, brown colour formation in sugar beet leaves was dependent on the amount of phenolics, which do not serve as a substrate of PPO. These non-substrate phenolics can engage in browning reactions by oxidative coupling and subsequent coupled oxidation of the products formed. Similar reactions might also be involved in covalent protein modification by phenolics, and therewith protein properties. High molecular weight PhT from L. digitata could potentially modify protein properties by non‑covalent interactions. L. digitata contained PhT with subunits mainly connected via C‑O-C linkages, as determined using NMR spectroscopy. Further mass spectrometric analysis revealed the presence of a wide range of oligomers with degrees of polymerisation between 3 and 27. The interaction between PhT and proteins (b-casein and bovine serum albumin) was studied using model systems with different pH values, representing the various environments throughout the ruminants digestive tract. Phlorotannins bound to protein independent of pH, and broadened the pH range of protein precipitation from 0.5 to ~1.5 pH unit around the protein’s pI. At the pH of the abomasum of 2-3, the proteins re-solubilised again, presumably by increase in their net charge. Due to their ability to form water insoluble complexes, PhT could improve ruminal fermentation in vitro in a dose dependent manner, resulting in lower methane production and ammonia (NH3) concentration. The decreased NH3 concentration reflected decreased dietary protein breakdown in the rumen, which is considered a nutritional and environmental benefit. </p

An Engineering Approach towards Action Refinement

In the abstract modelling of distributed systems we may need methods to replace abstract behaviours by more concrete behaviours which are closer to implementation mechanisms. Furthermore, we may want these methods to preserve the correctness of such a replacement. This paper introduces an approach towards action refinement in which an abstract action is replaced by a concrete activity. This approach is based on a careful consideration of the `action' and `causality relation' architectural concepts, which enable an abstract action to be replaced by many alternative concrete activities in a general way. This approach is based on the application of abstraction rules to determine whether a concrete activity conforms to an abstract action, considering the context in which the concrete activity and the abstract action are embedde

The multi-thermal and multi-stranded nature of coronal rain

In this work, we analyse coordinated observations spanning chromospheric, TR and coronal temperatures at very high resolution which reveal essential characteristics of thermally unstable plasmas. Coronal rain is found to be a highly multi-thermal phenomenon with a high degree of co-spatiality in the multi-wavelength emission. EUV darkening and quasi-periodic intensity variations are found to be strongly correlated to coronal rain showers. Progressive cooling of coronal rain is observed, leading to a height dependence of the emission. A fast-slow two-step catastrophic cooling progression is found, which may reflect the transition to optically thick plasma states. The intermittent and clumpy appearance of coronal rain at coronal heights becomes more continuous and persistent at chromospheric heights just before impact, mainly due to a funnel effect from the observed expansion of the magnetic field. Strong density inhomogeneities on spatial scales of 0.2"-0.5" are found, in which TR to chromospheric temperature transition occurs at the lowest detectable scales. The shape of the distribution of coronal rain widths is found to be independent of temperature with peaks close to the resolution limit of each telescope, ranging from 0.2" to 0.8". However we find a sharp increase of clump numbers at the coolest wavelengths and especially at higher resolution, suggesting that the bulk of the rain distribution remains undetected. Rain clumps appear organised in strands in both chromospheric and TR temperatures, suggesting an important role of thermal instability in the shaping of fundamental loop substructure. We further find structure reminiscent of the MHD thermal mode. Rain core densities are estimated to vary between 2x10^{10} cm^{-3} and 2.5x10^{11} cm^{-3} leading to significant downward mass fluxes per loop of 1-5x10^{9} g s^{-1}, suggesting a major role in the chromosphere-corona mass cycle.Comment: Abstract is only short version. See paper for full. Countless pages, figures (and movies, but not included here). Accepted for publication in the Astrophysical Journa