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   

Comparative toxicities of chlorinated biphenyls on sea urchin egg fertilisation and embryogenesis     

G. Pagano  M. Cipollaro  G. Corsale  A. Esposito  E. Ragucci  G.G. Giordano  N.M. Trieff   《Marine environmental research》1985,17(2-4)

The aim of this study was to compare the biological actions of selected chlorinated biphenyls (CB's) (with different degrees of chlorine substitution), using the sea urchin test system, for their ability to affect fertilisation, embryogenesis and mitotic activity. Sea urchin embryos were exposed to the test agents throughout larval development or for shorter intervals (e.g. before or after hatching). Sperm or eggs were exposed before fertilisation, thereafter the contaminants were removed from embryo cultures. The results showed maximal activities from medium-chlorinated (tetra- and hexachloro-substituted) compounds, as compared to low- and high-chlorinated biphenyls (mono-, di- and octachloro-substituted), at nominal levels ranging from 10⁻⁶m to 10⁻⁵m. This held true for the different parameters and treatment schedules. Developmental defects were only detected following post hatching exposure of embryos to CB's, whereas pre-hatching exposure failed to reveal any embryological or cytogenetic abnormalities.  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   

Hydrogeology of thermal waters in Viterbo area, central Italy     

V. Piscopo  M. Barbieri  V. Monetti  G. Pagano  S. Pistoni  E. Ruggi  D. Stanzione 《Hydrogeology Journal》2006,14(8):1508-1521

A conceptual hydrogeological model of the Viterbo thermal area (central Italy) has been developed. Though numerous studies have been conducted on its geological, geochemical and geothermal features, there is no generalized picture defining the origin and yield of the hydrothermal system. These latter aspects have therefore become the objectives of this research, which is based on new hydrogeological and geochemical investigations. The geological setting results in the coexistence of overlapped interacting aquifers. The shallow volcanic aquifer, characterized by fresh waters, is fed from the area around the Cimini Mountains and is limited at its base by the semiconfining marly-calcareous-arenaceous complex and low-permeability clays. To the west of Viterbo, vertical upflows of thermal waters of the sulphate-chloride-alkaline-earth type with higher gas contents, are due to the locally uplifted carbonate reservoir, the reduced thickness of the semiconfining layer and the high local geothermal gradient. The hot waters (30–60°C) are the result of deep circulation within the carbonate rocks (0.5–1.8 km) and have the same recharge area as the volcanic aquifer. The upward flow in the Viterbo thermal area is at least 0.1 m³/s. This flow feeds springs and deep wells, also recharging the volcanic aquifer from below.  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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Solar irradiance in NW Italy     

V. Pasquale 《Theoretical and Applied Climatology》1987,38(2):85-92

Summary An analysis is made of the monthly mean global and diffuse irradiance values recorded by the Genoa University Geophysical Institute radiation network to derive characteristic elements of the solar climate in four typical NW Italy locations. Diffuse irradiation was estimated for the stations where diffuse irradiation data were not recorded, by using correlations between measured data with clearness parameter and sunshine index. Local factors which affect the attenuation of global irradiance under cloudless skies are discussed.

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Zusammenfassung Die vom Strahlungsaufzeichnungsnetz der Geophysikalischen Hochschule Genua aufgenommenen monatlichen Mittelwerte der Global- und Himmelsstrahlung werden untersucht, wobei charakteristische Elemente des Sonnenklimas von vier typischen Stationen in NW-Italien deduziert werden. Die Himmelsstrahlung wird für diejenigen Stationen, wo diese nicht aufgenommen wird, durch Anwendung von Korrelationen zwischen Meßwerten und einem Klarheitsparameter bzw. einer Sonnenscheinzahl geschätzt. Außerdem werden örtliche Faktoren diskutiert, die die Schwächung der Globalstrahlung unter wolkenlosem Himmel bestimmen.

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This paper is dedicated to the memory of Prof. Mario Bossolasco of whom the author had the honour of being a pupil.

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With 2 Figures  相似文献   

Detecting patterns of climate change in long-term forecasts of marine environmental parameters     

Gianpaolo Coro  Pasquale Pagano  Anton Ellenbroek 《International Journal of Digital Earth》2020,13(5):567-585

ABSTRACT

Forecasting environmental parameters in the distant future requires complex modelling and large computational resources. Due to the sensitivity and complexity of forecast models, long-term parameter forecasts (e.g. up to 2100) are uncommon and only produced by a few organisations, in heterogeneous formats and based on different assumptions of greenhouse gases emissions. However, data mining techniques can be used to coerce the data to a uniform time and spatial representation, which facilitates their use in many applications. In this paper, streams of big data coming from AquaMaps and NASA collections of 126 long-term forecasts of nine types of environmental parameters are processed through a cloud computing platform in order to (i) standardise and harmonise the data representations, (ii) produce intermediate scenarios and new informative parameters, and (iii) align all sets on a common time and spatial resolution. Time series cross-correlation applied to these aligned datasets reveals patterns of climate change and similarities between parameter trends in 10 marine areas. Our results highlight that (i) the Mediterranean Sea may have a standalone ‘response’ to climate change with respect to other areas, (ii) the Poles are most representative of global forecasted change, and (iii) the trends are generally alarming for most oceans.  相似文献