Aerogel keystones: Extraction of complete hypervelocity impact events from aerogel collectors     

Andrew J. Westphal  Christopher Snead  Anna Butterworth  Giles A. Graham  John P. Bradley  Sa&#x;a Bajt  Patrick G. Grant  Graham Bench  Sean Brennan  Piero Pianetta 《Meteoritics & planetary science》2004,39(8):1375-1386

Abstract— In January 2006, the Stardust mission will return the first samples from a solid solar system body beyond the Moon and the first samples of contemporary interstellar dust ever collected. Although sophisticated laboratory instruments exist for the analysis of Stardust samples, techniques for the recovery of particles and particle residues from aerogel collectors remain primitive. Here, we describe our recent progress in developing techniques for extracting small volumes of aerogel, which we have called “keystones,” which completely contain particle impacts but minimize the damage to the surrounding aerogel collector. These keystones can be fixed to custom‐designed micromachined silicon fixtures (so called “microforklifts”). In this configuration, the samples are self‐supporting, which can be advantageous in situations where interference from a supporting substrate is undesirable. The keystones may also be extracted and placed onto a substrate without a fixture. We have also demonstrated the capability of homologously crushing these unmounted keystones for analysis techniques that demand flat samples.  相似文献   

New insights into volcanic processes from deep mining of the southern diatreme within the Argyle lamproite pipe,Western Australia     

Rayner  Murray J.  Moss  Stephen W.  Lorenz  Volker  Jaques  A. Lynton  Boxer  Grant L.  Smith  Chris B.  Webb  Kimberley 《Mineralogy and Petrology》2018,112(2):351-363

Underground mining and deep drilling of the richly diamondiferous ~1.2 Ga Argyle lamproite in Western Australia has prompted a re-evaluation of the geology of the pipe. Argyle is considered to be a composite pipe that formed by the coalescence of several diatremes and has been offset and elongated by post-emplacement faulting. Recent geological studies have recognised at least five distinct volcaniclastic lamproite lithofacies with differing diamond grades. The new data suggest that the centre of the southern (main) diatreme is occupied by well-bedded, olivine lamproite lapilli tuff with very high diamond grades (>10 ct/t). Characteristic features include a clast-supported fabric and high modal abundance of densely packed lamproite lapilli and coarse-grained, likely mantle-derived olivine now replaced by serpentine and/or talc. The persistence of small-scale graded and cross-bedding in this lithofacies to depths of ~1.5 km below the original surface prior to erosion suggests phreatomagmatic volcanism forming the diatreme was syn-eruptively accompanied by subsidence of the tephra, maintaining a steep-walled diatreme in the water-saturated country rock sediments.

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A conceptual model of avalanche hazard     

Grant Statham  Pascal Haegeli  Ethan Greene  Karl Birkeland  Clair Israelson  Bruce Tremper  Chris Stethem  Bruce McMahon  Brad White  John Kelly 《Natural Hazards》2018,90(2):663-691

This conceptual model of avalanche hazard identifies the key components of avalanche hazard and structures them into a systematic, consistent workflow for hazard and risk assessments. The method is applicable to all types of avalanche forecasting operations, and the underlying principles can be applied at any scale in space or time. The concept of an avalanche problem is introduced, describing how different types of avalanche problems directly influence the assessment and management of the risk. Four sequential questions are shown to structure the assessment of avalanche hazard, namely: (1) What type of avalanche problem(s) exists? (2) Where are these problems located in the terrain? (3) How likely is it that an avalanche will occur? and (4) How big will the avalanche be? Our objective was to develop an underpinning for qualitative hazard and risk assessments and address this knowledge gap in the avalanche forecasting literature. We used judgmental decomposition to elicit the avalanche forecasting process from forecasters and then described it within a risk-based framework that is consistent with other natural hazards disciplines.  相似文献   

Appropriate aspirations for effective post-mining restoration and rehabilitation: a response to Kaźmierczak et al.     

Adam T. Cross  Renee Young  Paul Nevill  Tein McDonald  Karel Prach  James Aronson  Grant W. Wardell-Johnson  Kingsley W. Dixon 《Environmental Earth Sciences》2018,77(6):256

Confusion surrounding the definition and application of terminology in post-mining ecological repair has resulted in uncertainty for industry, the scientific community and regulators. This lack of clarity may underrepresent high aspirations or could be misused to disguise low aspirations and so is problematic for setting objectives, establishing goals and assessing recovery trajectories. We respond to a recently published analysis of the ecosystem repair literature, where we highlight inconsistencies stemming from inadequate reference to a large proportion of the restoration and rehabilitation literature. We outline increasingly well-accepted and internationally applied definitions concerning the restoration and recovery process and invite both the mining industry and policy-makers to re-examine their terminology in the interests of attaining an internationally agreed nomenclature. Clarity in the use and understanding of terminology will align post-mining targets with community expectation, enhance the capacity of the mining industry to understand and meet these targets, and foster better analysis and more industry-relevant discussion of recovery methodologies by the scientific community and practitioners.  相似文献   

A geoprivacy manifesto   总被引：1，自引：0，他引：1       下载免费PDF全文

Carsten Keßler  Grant McKenzie 《Transactions in GIS》2018,22(1):3-19

As location‐enabled technologies are becoming ubiquitous, our location is being shared with an ever‐growing number of external services. Issues revolving around location privacy—or geoprivacy—therefore concern the vast majority of the population, largely without knowing how the underlying technologies work and what can be inferred from an individual's location (especially if recorded over longer periods of time). Research, on the other hand, has largely treated this topic from isolated standpoints, most prominently from the technological and ethical points of view. This article therefore reflects upon the current state of geoprivacy from a broader perspective. It integrates technological, ethical, legal, and educational aspects and clarifies how they interact and shape how we deal with the corresponding technology, both individually and as a society. It does so in the form of a manifesto, consisting of 21 theses that summarize the main arguments made in the article. These theses argue that location information is different from other kinds of personal information and, in combination, show why geoprivacy (and privacy in general) needs to be protected and should not become a mere illusion. The fictional couple of Jane and Tom is used as a running example to illustrate how common it has become to share our location information, and how it can be used—both for good and for worse.  相似文献   

A fundamental dispute: A discussion of “On some fundamentals of igneous petrology” by Bruce D. Marsh,Contributions to Mineralogy and Petrology (2013) 166: 665–690     

Rais Latypov  Tony Morse  Brian Robins  Richard Wilson  Grant Cawthorn  Christian Tegner  Marian Holness  Charles Lesher  Steve Barnes  Brian O’Driscoll  Ilya Veksler  Michael Higgins  Allan Wilson  Olivier Namur  Sofya Chistyakova  Richard Naslund  Peter Thy 《Contributions to Mineralogy and Petrology》2015,169(2):1-10

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Preface: Hydrogeology of shallow thermal systems     

Diana M. Allen  Peter Bayer  Grant Ferguson  Philipp Blum 《Hydrogeology Journal》2014,22(1):1-6

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The political ecology of territoriality: territorialities in farmer–herder relationships in Northern Ghana     

Rita Yembilah  Miriam Grant 《GeoJournal》2014,79(3):385-400

Fulani herder and farmer relationships in West Africa have always been troublesome as a result of farmers’ fundamental rejection of the herders’ inroads into their areas and also because of increased competition for available resources. In countries such as Ghana, local and even national campaigns have been launched to expel the herders but they persist. This case-study which utilised interviews and group discussions involving farmers and herders, sought to understand the dynamics and subtleties of herders’ resilience in an environment where natural resource access and use rights are tied to common property principles and where herders have no enshrined land and resource rights. Using territoriality as the analytical capsule, we found that the herders’ persistence is related to mainly non-territoriality where the goal is to influence relationships and resource access but not control area. Categorising their non-territorial expression into persuasive and aggressive forms, we provide a new platform for deconstructing farmer-herder relationships in the West African sub-region.  相似文献   

A comparison of usefulness of 2D and 3D representations of urban planning     

Grant Herbert 《制图学和地理信息科学》2013,40(1):22-32

Very little existing literature has addressed the issues of the perceived usefulness of 3D visualizations over 2D and the use of cartographic shadow representations in the planning community. Urban planning has moved toward a 3D, geographic-information-system-centric, and functional decision support framework. This study aims to examine the preferences of urban planning professionals with respect to 2D and 3D visualizations in a case study. The authors built a 3D representation of a proposed building along with the existing urban environment in Queenstown, New Zealand and conducted a usefulness test through a survey and interview. Based on the survey, the study evaluated the degree of task utility perceived in each visualization method, the effect on the mental image, and shadow representation preferences. The findings support the literature that the benefits of using a 2D or 3D model are closely related to the types of planning tasks undertaken. The findings also reveal a complex view of planning activities, suggesting that planners themselves cannot be treated as a single group for research purposes.  相似文献   

Observations and implications of damage from the magnitude Mw 6.3 Christchurch, New Zealand earthquake of 22 February 2011   总被引：1，自引：1，他引：0  

Sean Wilkinson  Damian Grant  Elizabeth Williams  Sara Paganoni  Stuart Fraser  David Boon  Anna Mason  Matthew Free 《Bulletin of Earthquake Engineering》2013,11(1):107-140

This paper describes the observations made by a reconnaissance team following the 22nd February 2011, M_w 6.3, Christchurch, New Zealand earthquake (GNS Science, 2011). The team comprised of members of the UK based Earthquake Engineering Field Investigation Team who spent 5 days collecting observations on damage resulting from the earthquake. Although the magnitude of this earthquake was not particularly high (M_w 6.3), the shallow focus and close proximity resulted in locally very high ground motions, widespread damage and 182 fatalities. The earthquake is also particularly notable for the widespread liquefaction it caused, landslides and rockfalls in the hills south of Christchurch, and the significant damage suffered by unreinforced masonry and historic structures. Over wide areas of central Christchurch, recorded accelerations were in excess of those required by the current New Zealand seismic loadings standard (NZS1170.5:2004: Standards New Zealand 2004) and therefore the earthquake presented a valuable opportunity to assess performance of modern buildings under code-level ground acceleration.  相似文献