2,997 research outputs found
Petrographic and mid-infrared spectroscopy study of shocked feldspar in the Asuka-881757 Lunar gabbro meteorite sample
Abstract
We investigated three types of shocked feldspar in the Asuka-881757,531-2 sample with midinfrared spectroscopy (reflectance mode). Under the petrographic microscope three types of site were characterized by (1) undulatory extinction, (2) undulatory extinction with isotropic patches and decreased interference color, and (3) isotropic, lath-shaped feldspars, which is indicative of maskelynite. The IR emissivity maximum (Christiansen feature=CF) changes with the chemical composition of feldspar. One of the Christiansen composition features exhibits a wave length peak of 1234 cmâ1 for anorthite; another feature appears at 1245 cmâ1 for maskelynite (Palomba et al. 2006).
With the help of IR spectroscopy we observed three vibrational types in our spectra: (1) peaks of depolimerization of SiO4 tetrahedra (500â650 cmâ1, 950â1150 cmâ1), (2) peaks of stretching and bending vibrational modes of SiO6 octahedra (750â850 cmâ1), and (3) Si-O stretching vibration of SiO4 units (Johnson and Hörz 2003; Johnson et al. 2003, 2007). All these vibration types were observed at the less shocked sites. In the spectrum of highly shocked maskelynite only a broader band close to 1000 cmâ1 was observed, which is the main vibrational band of maskelynite (Palomba et al. 2006). The calculated FWHM showed the disordering rate of shocked feldspars. On the basis of the measurements it could be concluded that the estimated shock pressure range gradually increases from 17â35 GPa for different degrees of undulatory sites, to 35â45 GPa for maskelynite sites
The anaerobic digestion of sheep manure in self-designed low-cost biogas reactor
One of the possible utilisation methods for organic wastes is anaerobe decomposition (fermentation). The main product of this process is biogas which is usually used for energy purposes due to its composition (mainly methane and carbon dioxide). The residual solid material after fermentation can be used as soil conditioner.
Lab-scale fermentation can be carried out using the âVDI 4630 â Fermentation of organic materials Characterisation of the substrate, sampling, collection of material data, fermentation testsâ standard. Based on the conditions described in the standard, a small-scale low-budget reactor system were prepared. The temperature during the holding time was controlled with water bath and the gas production was determined with fluid displacement method. A peristaltic pump was used for the recirculation of the gas to mix the base material. Furthermore, the temperatures of the environment, the water baths and the inside of each reactor was automatically registered on a data collector
Raman and infrared spectroscopy of feldspars in lunar meteorites (Asuka-881757 and Yamato- 86032)
We investigated shock metamorphism of two lunar meteorites (Asuka-881757 and Yamato-86032). We measured shocked lunar feldspars with infrared and Micro-Raman spectroscopy. These
methods are very sensitive for changing crystal lattice after amorphisation derived to shock metamorphism. With infrared spectroscopy were four different stage schocked feldspar measured, and with Micro-Raman spectroscopy 3 maskelynite grains were measured
Two body problem on two point homogeneous spaces, invariant differential operators and the mass center concept
We consider the two body problem with central interaction on two point
homogeneous spaces from point of view of the invariant differential operators
theory. The representation of the two particle Hamiltonian in terms of the
radial differential operator and invariant operators on the symmetry group is
found. The connection of different mass center definitions for these spaces to
the obtained expression for Hamiltonian operator is studied.Comment: 26 pages, LaTeX, no figures, text improve
Forsterite from Kaba Meteorite and its Implication for Astromineralogy
The Tenth Symposium on Polar Science/Poster presentations: [OA] Antarctic meteorites, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc
Petrographic and micro-Raman study of thermal and shock metamorphism in MezĆmadaras, Knyahinya and MĂłcs L-Chondrites
We investigated three Hungarian L-chondrites: MezĆmadaras, Knyahinya, and MĂłcs sample. In Knyahinya chondrite, two phenomena were observed as follows: the weak mosaicism (S4) and mechanical twins in pyroxene. The MĂłcs sample is characterized by strong shock metamorphic effects such as high density of fractures and abundant shock-veins. Planar Deformation Features (PDFs) were identified in two olivine grains, and an olivine grain shows well-developed Planar Fractures (PFs). In MezĆmadaras sample, there are irregular fractures (S1), and PFs (S3), and mechanical twins in pyroxene. We have reinvestigated of these meteorite samples using Raman spectroscopy for the identification of shock-metamorphic effects, which occurred in the structure changes of olivine and pyroxene grains. The olivine doublet peak position is shifted to higher wavenumbers, due to partly disordered olivine structure. We observed that minerals with mechanical twins exhibit less interference color, compared to the non-shocked minerals, especially pyroxene. It is important to note that, the mechanical twins were complicated to describe, only the direction of the deformation was determined. On the basis of the measured FWHM, the following structural disordering degree of the selected samples can be determined as a (growing rate): Castle Rock, MezĆmadaras, Shergotty and MĂłcs. The result reveals that amorphization rate is the highest in MĂłcs and Shergotty pyroxene grains
A review of a carbonaceous chondrite: what can we learn from the Kaba meteorite?
The Tenth Symposium on Polar Science/Poster presentations: [OA] Antarctic meteorites, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc
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