Small hypervelocity particles captured in aerogel collectors: Location,extraction, handling and storage     

Andrew J. Westphal  Christopher Snead  Janet Borg  Eric Quirico  Pierre‐Ivan Raynal  Michael E. Zolensky  Gianluca Ferrini  Luigi Colangeli  Pasquale Palumbo 《Meteoritics & planetary science》2002,37(6):855-865

Abstract— It has now been about a decade since the first demonstrations that hypervelocity particles could be captured, partially intact, in aerogel collectors. But the initial promise of a bonanza of partially‐intact extraterrestrial particles, collected in space, has yet to materialize. One of the difficulties that investigators have encountered is that the location, extraction, handling and analysis of very small (10 μm and less) grains, which constitute the vast majority of the captured particles, is challenging and burdensome. Furthermore, current extraction techniques tend to be destructive over large areas of the collectors. Here we describe our efforts to alleviate some of these difficulties. We have learned how to rapidly and efficiently locate captured particles in aerogel collectors, using an automated microscopic scanning system originally developed for experimental nuclear astrophysics. We have learned how to precisely excavate small access tunnels and trenches using an automated micromanipulator and glass microneedles as tools. These excavations are only destructive to the collector in a very small area—this feature may be particularly important for excavations in the precious Stardust collectors. Using actuatable silicon microtweezers, we have learned how to extract and store “naked” particles—essentially free of aerogel—as small as 3 μm in size. We have also developed a technique for extracting particles, along with their terminal tracks, still embedded in small cubical aerogel blocks. We have developed a novel method for storing very small particles in etched nuclear tracks. We have applied these techniques to the extraction and storage of grains captured in aerogel collectors (Particle Impact Experiment, Orbital Debris Collector Experiment, Comet‐99) in low Earth orbit.  相似文献   

A stratigraphic and tectonofacies framework of the “calcari aLucina” in the Apennine Chain,Italy     

F. Ricci Lucchi  G. B. Vai 《Geo-Marine Letters》1994,14(2-3):210-218

The Apennine Chain provides the first example of stratigraphic (time) and synsedimentary tectonic (space) distribution of the calcari aLucina Miocene equivalents of modern cold-vent carbonates. Chemosynthetic faunal assemblages and related carbonate deposits are found at different stratigraphic levels, with peaks during Langhian-Serravallian and late Tortonian-early Messinian times. A general increase in frequency and volume occurs with time. A genetic link between venting and the Messinian Evaporite event is difficult to demonstrate. However,Lucina limestones are limited to preevaporitic times, and their maximum abundance is reached just before the onset of the Messinian Evaporite accumulation.Lucina limestones occur in almost all tectofacies of the orogen, from backland to foreland.  相似文献   

The Deep-Sea Fan deposits of the miocene Marnoso-Arenacea formation,northern Apennines     

Franco Ricci Lucchi 《Geo-Marine Letters》1983,3(2-4):203-210

Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored (choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis on “inner” or “autocyclic” mechanisms.  相似文献   

Low multipath antennas for GNSS-based attitude determination systems applied to high-altitude platforms   总被引：1，自引：1，他引：0  

Luigi Boccia  Pasquale Pace  Giandomenico Amendola  Giuseppe Di Massa 《GPS Solutions》2008,12(3):163-171

High-altitude platforms (HAPs) are a flexible and attractive technology for providing innovative wireless services. These aerial platforms can be successfully employed for mobile or broadband communications and for disaster monitoring or response. However, one of the open issues is whether HAP stations can provide reliable services without temporal outages owing to stratospheric winds that can cause positional and attitude instabilities thus affecting the communication system operation. To counteract this issue, one possible solution is to use reconfigurable antennas whose pointing direction can be adjusted depending on the platform spatial orientation. However, this would require real-time three-axial attitude data. As a possible solution, this paper will review the potential of GNSS-based attitude determination systems with reference to HAP stations. In particular, it will be shown how the use of a particular class of low multipath and lightweight antennas can provide a high degree of accuracy without altering the avionic ballast.  相似文献   

Inferring hydro-geothermal parameters from advectively perturbed thermal logs     

M. Verdoya  V. Pasquale  P. Chiozzi 《International Journal of Earth Sciences》2008,97(2):333-344

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Continental drift and rotation of the Earth     

Pasquale Sconzo 《Celestial Mechanics and Dynamical Astronomy》1980,22(1):61-62

It is shown, based on certain simplifying assumptions, that an island the size of Greenland, drifting across the North Atlantic at 10 m/century produces a change in secular rotation T=0.01 s.Presented at the Symposium Star Catalogues, Positional Astronomy and Celestial Mechanics, held in honor of Paul Herget at the U.S. Naval Observatory, Washington, November 30, 1978.  相似文献   

The urban role of a new university: a case study of Chieti-Pescara, Abruzzo, Italy     

Mosè Ricci 《GeoJournal》1997,41(4):319-324

The results of the study on the urban role of the University by the Pescara School of Architecture show that a new approach for this subject is needed. A university should be considered not only as a culture-producing institution, but also as an income producer and distributor for the area. In other words it is possible to promote the university as a strategic investment for development; and as a modernization and requalification factor both of the local production and of the human settlement and territorial structures. In the Abruzzo Region, and particularly in the Chieti-Pescara area, the university as a strategic intervention and its possible interactions with the urban system, is closely related to the nature of the urban phenomenon in this particular geographical context. Funds invested by the State in the university flow directly to individuals through the economic behavior of the university users themselves, according to an only partially measurable process. At present, in the Pescara area, it can be assumed that such economic contribution to the local system development is greater that the proceedings of the tourism industry, in an area with a well established tourist appeal.  相似文献   

Palaeomagnetic study on Vesuvius lava flows     

Pasquale Tiano  Alberto Incoronato  Donald H. Tarling 《Geophysical Journal International》2005,163(2):518-526

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Do earthquake storms repeat in the Apennines of Italy?     

Claudio Chiarabba  Pasquale De Gori  Alessandro Amato 《地学学报》2011,23(5):300-306

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Archaeoseismological evidence of past earthquakes in Rome (fifth to ninth century A.D.) used to quantify dating uncertainties and coseismic damage     

Fabrizio Galadini  Giovanni Ricci  Emanuela Falcucci  Camilla Panzieri 《Natural Hazards》2018,94(1):319-348

The transformation of Rome during the Late Antiquity and the Early Middle Ages has been investigated by archaeologists and historians. Social and political changes are the main aspects which led to a progressive modification of the urban framework; abandonment, spoliation and transformation of buildings are quite diffused as documented by the archaeological literature. The consequence of these practices is a higher vulnerability of the buildings which, from the seismological point of view, played a main role in increasing the effects of seismic shaking. A number of earthquakes have struck Rome during the period of investigation (fifth to ninth century A.D.), known from historical sources: 443, 484–508, 618, 801, 847; in some cases (443, 484–508, 801) damage has been documented. In contrast, the archaeological sources characterise collapse layers and evidence of destruction at different sites with changing and not always conclusive chronological constraints. Consequently, collapse and destruction have been alternatively attributed to the above-mentioned earthquakes. Through a geoarchaeological and stratigraphic analysis of potentially coseismic collapse units, we want (1) to describe the archaeoseismic evidence derived from recent excavations and from the available literature (e.g. Piazza Madonna di Loreto, Piazza Venezia, Palazzo Valentini Crypta Balbi, Colosseo, Basilica Hilariana, Basilica di Santa Petronilla, Santa Maria Antiqua,…); (2) to discuss the chronological problems and the uncertainty of attribution of the collapse units to known historical earthquakes; (3) to discuss the earthquake damage exaggeration due to erroneous attribution of seismic origin to the evidence of destruction derived from archaeological data. Finally, we will infer the role that earthquakes may have had on the development of the urban landscape in the fifth to ninth century A.D.  相似文献