Sample processing and initial analysis techniques for Antarctic micrometeorites

Based on our initial visual selection (IVS) criteria and low vacuum (LV)-SEM/EDS data, we successfully selected candidates of unmelted chondritic Antarctic micrometeorites (AMMs) from the unsorted sample set collected by Maurette\u27s group in 1991. AEM data of some of the selected microparticles show that they are unmelted but probably dehydrated AMMs. An AMM candidate, 91-1-C4,contains ferroan (around Fo30) olivine grains which have planar channels parallel to (001). Their textures quite resemble those shown in the initial stage of iddingsite formation of olivine phenocrysts in terrestrial basalts. These findings indicate that some olivine crystals in AMMs can be altered even in the Antarctic environment

Effects of neighbouring planets on the formation of resonant dust rings in the inner Solar System

Context. Findings by the Helios and STEREO mission have indicated the presence of a resonant circumsolar ring of dust associated with Venus. Attempts to model this phenomenon as an analogue to the resonant ring of Earth - as a result of migrating dust trapped in external mean-motion resonances (MMRs) - have so far been unable to reproduce the observed dust feature. Other theories of origin have recently been put forward. However, the reason for the low trapping efficiency of Venus's external MMRs remains unclear. Aims. Here we look into the nature of the dust trapping resonant phenomena that arise from the multi-planet configuration of the inner Solar System, aiming to add to the existent understanding of resonant dust rings in single planet systems. Methods. We numerically modelled resonant dust features associated with the inner planets and specifically looked into the dependency of these structures and the trapping efficiency of particular resonances on the configuration of planets. Results. Besides Mercury showing no resonant interaction with the migrating dust cloud, we find Venus, Earth, and Mars to considerably interfere with each other's resonances, influencing their ability to form circumsolar rings. We find that the single most important reason for the weakness of Venus's external MMR ring is the perturbing influence of its outer neighbour - Earth. In addition, we find Mercury and Mars to produce crescent-shaped density features, caused by a directed apsidal precession occurring in particles traversing their orbital region

Micro-abrasion package capture cell experiment on the trailing edge of LDEF: Impactor chemistry and whipple bumper shield efficiencies

Four of the eight available double layer microparticle capture cells, flown as the experiment A0023 on the trailing (West) face of LDEF, have been extensively studied. An investigation of the chemistry of impactors has been made using SEM/EDX techniques and the effectiveness of the capture cells as bumper shields has also been examined. Studies of these capture cells gave positive EDX results, with 53 percent of impact sites indicating the presence of some chemical residues, the predominant residue identified as being silicon in varying quantities

A case report of acute dermatitis that developed during an experiment examining the bromination of 3-hexylthiophene

Occupational cases with allergic reaction to fragrance substances, which refer to various chemicals providing aroma characteristics, are arising with its recent usage diversification from pharmaceutical, perfume industry to aromatic remedies. However, chemicals responsible for fragrance allergy have hardly been identified because its component is complex and its sensitization is not frequent. This report will present a case of acute allergic dermatitis that is likely induced by 3-hexylthiophene, one of aromatic compounds often contained in fragrance substances. The case, who was a 27-year male researcher engaged in organic chemical synthesis for six years, was exposed to 3-hexylthiophene and its product (2-bromo-3-hexylthiophene) through an experiment in May 2004 and itching, swelling and eczema immediately developed from face to back. This case of sensitization to 3-hexylthiophene suggests that it be a possible allergen for fragrance allergy

Leonid Meteor Observer in LEO: A University Microsatellite to Observe a Meteor Shower from Space

This paper presents university-based design and development of a micro-satellite for the observation of a meteor shower from the low Earth orbit. The satellite will be launched as a piggy-back payload of a commercial rocket launcher, a few weeks before the 2001 or 2002 Leonid meteor maximum in which thousands of meteors are scienti_cally expected. The goal of the mission is to conduct the scienti_c observation of the prospective meteor outburst from out of atmosphere, counting the meteors in the large coverage of the night sky looked down on Earth and obtaining visible-Ultra Violet spectrographs of the meteor. Possible launch opportunity remains to be seen, but the designs of the satellite bus and scientific payloads are now initiated