The Case for the Median Fragment Size as a Better Fragment Size Descriptor than the Mean     

Finn Ouchterlony 《Rock Mechanics and Rock Engineering》2016,49(1):143-164

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Tailings composition effects on shear strength behavior of co-mixed mine waste rock and tailings   总被引：1，自引：0，他引：1  

Megan M. Jehring  Christopher A. Bareither 《Acta Geotechnica》2016,11(5):1147-1166

The objective of this study was to evaluate the effect of mine tailings composition on shear behavior and shear strength of co-mixed mine waste rock and tailings (WR&T). Crushed gravel was used as a synthetic waste rock and mixed with four types of tailings: (1) fine-grained garnet, (2) coarse-grained garnet, (3) copper, and (4) soda ash. Co-mixed WR&T specimens were prepared to target mixture ratios of mass of waste rock to mass of tailings (R) such that tailings “just filled” interparticle void space of the waste rock (i.e., optimum mixture ratio, R _opt). Triaxial compression tests were conducted on waste rock, tailings, and mixed waste at effective confining stresses (\(\sigma_{\text{c}}^{{\prime }}\)) ranging from 5 to 40 kPa to represent stresses anticipated in final earthen covers for waste containment facilities. Waste rock and co-mixed WR&T specimens were 150 mm in diameter by 300 mm tall, whereas tailings specimens were 38 mm in diameter by 76 mm tall. Shear strength was quantified using effective stress friction angles (?′) from undrained tests: ?′ for waste rock was 37°, ?′ for tailings ranged from 34° to 41°, and ?′ for WR&T mixtures ranged from 38° to 40°. Thus, shear strength of co-mixed WR&T was comparable to waste rock regardless of tailings composition. Shear behavior of WR&T mixtures was a function of R and tailings composition. Tailings influenced shear behavior for R < R _opt and when tailings predominantly were silt. Shear behavior was influenced by waste rock for R ≥ R _opt and when tailings predominantly were sand or included clay particles.  相似文献   

The role of social capital,personal networks,and emergency responders in post-disaster recovery and resilience: a study of rural communities in Indiana     

Arif Mohaimin Sadri  Satish V. Ukkusuri  Seungyoon Lee  Rosalee Clawson  Daniel Aldrich  Megan Sapp Nelson  Justin Seipel  Daniel Kelly 《Natural Hazards》2018,90(3):1377-1406

The factors that explain the speed of recovery after disaster remain contested. While many have argued that physical infrastructure, social capital, and disaster damage influence the arc of recovery, empirical studies that test these various factors within a unified modeling framework are few. We conducted a mail survey to collect data on household recovery in four small towns in southern Indiana that were hit by deadly tornadoes in March 2012. The recovery effort is ongoing; while many of the homes, businesses, and community facilities were rebuilt in 2013, some are still under construction. We investigate how households in these communities are recovering from damage that they experienced and the role of social capital, personal networks, and assistance from emergency responders on the overall recovery experience. We used an ordered probit modeling framework to test the combined as well as relative effects of (a) damage to physical infrastructures (houses, vehicles, etc.); (b) recovery assistance from emergency responders (FEMA) as well as friends and neighbors; (c) personal network characteristics (size, network density, proximity, length of relationship); (d) social capital (civic engagement, contact with neighbors, trust); and (e) household characteristics. Results show that while households with higher levels of damage experienced slower recovery, those with recovery assistance from neighbors, stronger personal networks, and higher levels of social capital experienced faster recovery. The insights gained in this study will enable emergency managers and disaster response personnel to implement targeted strategies in facilitating post-disaster recovery and community resilience.  相似文献   

Danian cool-water coral reefs in southern Scandinavia localised over seafloor highs     

Morten Bjerager  Finn Surlyk  Holger Lykke-Andersen  Nicolas Thibault  Lars Stemmerik 《Marine and Petroleum Geology》2010

Danian (Paleocene) reefs formed by ahermatypic scleractinian corals in relatively deep water are known in a few localities in southern Scandinavia. Reflection and shallow seismic profiles, and samples from drilling and scuba diving in bridge pier excavations in Øresund, the strait between Denmark and Sweden, for the first time allow interpretation of the factors that controlled the localisation of the reefs.  相似文献   

Environmental technology—Combining environmental improvement and industrial development     

Finn Kristensen 《Marine pollution bulletin》1994,29(6-12):559-561

This paper briefly gives the Norwegian government's perspective and role in promoting developments in environmental technologies. These are necessary to create environmental improvements, and thus comply with environmental standards, against a background of increasing industrial demands and developments. The role of governments in promoting and increasing co-operation and collaboration with industry is discussed. For example, the European EUREKA programme aims to promote advanced technologies but against the present environmentally sound criteria.  相似文献   

Desertification,drought and landcare: Australia's role in an international convention to combat desertification     

Martin Williams  Megan McCarthy  Geoff Pickup 《The Australian geographer》1995,26(1):23-32

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A review of the metallogeny and tectonics of the Lachlan Orogen     

Megan A. Hough  Frank P. Bierlein  Andy R. Wilde 《Mineralium Deposita》2007,42(5):435-448

Future mineral exploration within eastern Australia will be enhanced by resolving the tectonic evolution of the Lachlan Orogen to establish the spatial and temporal terrane distribution of the various mineral deposits. The Lachlan Orogen, from north-eastern Tasmania through to central and eastern New South Wales, is host to a number of major mineral deposit styles—including orogenic gold (e.g. Stawell, Ballarat, Bendigo), volcanic-hosted massive sulphide (e.g. Woodlawn, Currawong), sediment-hosted Cu–Au (e.g. Cobar Basin deposits), porphyry Au–Cu (e.g. Cadia, Parkes, Cowal) and granite-related Sn (e.g. Ardlethan, Beechworth). Each of these mineral deposit styles is a sensitive and diagnostic indicator of the prevalent tectonic environment during their formation. In this review, we briefly summarise the deposit- to large-scale factors that define the diverse metallogenic evolution of the Lachlan Orogen. This overview is intended to “set the scene” for subsequent specialist papers published in this thematic issue on the metallogeny and tectonics of the Lachlan Orogen in south-east Australia.  相似文献   

Theoretical intensity ratios for some Fe XIII coronal lines     

G. D. Finn  Donald A. Landman 《Solar physics》1973,30(2):381-384

Theoretical values for the relative intensities of the Fe XIII lines 110747, 110798, and 3388 are presented as functions of electron density using recent values of the cross-section for collisionl excitation by protons. Our results are compared with those of Chevalier and Lambert.  相似文献   

An evaluation of hemolymph cholinesterase activities in the tropical scallop,Euvola (Pecten) ziczac,for the rapid assessment of pesticide exposure     

Owen R  Buxton L  Sarkis S  Toaspern M  Knap A  Depledge M 《Marine pollution bulletin》2002,44(10):1010-1017

The use of sequential measurements of hemolymph cholinesterase activities as a non-invasive biomarker of seasonal organophosphate/carbamate exposure was investigated for the tropical scallop, Euvola (Pecten) ziczac. Overall activities of both acetylcholinesterase and butyrylcholinesterase were relatively high compared to studies with bivalve tissues. Acute in vivo experiments showed inhibition of hemolymph acetylcholinesterase activity at concentrations of the organophosphate insecticide chlorpyrifos of 0.1, 1 and 10 ng l(-1). Monthly sampling of hemolymph from scallops at two sites in Bermuda over a 15 month period showed seasonal acetylcholinesterase and butyrylcholinesterase inhibition. Direct and indirect evidence suggests that this inhibition did not relate to biochemical or physiological changes associated with gonad maturation and spawning, but rather reflected diffuse contamination of the marine environment by cholinesterase inhibitors or increased bioavailability of such inhibitors at these times. Repetitive sampling of scallop hemolymph for cholinesterase activities represents a rapid, sensitive and non-invasive method for assessing seasonal, sublethal pesticide exposure in these commercially important bivalves and suggests a wider use in marine pollution monitoring.  相似文献   

Application of the UKCIP02 climate change scenarios: Reflections and lessons learnt     

Megan Gawith  Roger Street  Richard Westaway  Anna Steynor 《Global Environmental Change》2009,19(1):113-121

The UKCIP02 climate change scenarios have become the standard reference for climate change in the UK since their release in 2002. This paper describes and reflects on the ways in which they have been applied. It then identifies some strengths, weaknesses and barriers to their application, and extracts key lessons that may inform the development and provision of future climate change scenarios.Analysis of the application of UKCIP02 shows that the scenarios have been used primarily as a communication device, as well as for scientific research and to inform policy and decision-making on climate change. They have played a critical role in raising awareness on climate change and in engaging organisations in the need to adapt. Their presentation in an accessible style, and their availability in a variety of formats, greatly facilitated their uptake. However, analysis has also revealed weaknesses which served as barriers to their uptake. Some of these, such as file format and accessibility issues, were readily overcome through technical solutions. Others, such as the issue of how to use uncertain information in decision-making, have only been partially addressed and remain an outstanding challenge for future scenario packages. Two key lessons have emerged which may benefit the provision of future climate scenarios in the UK and elsewhere. First, it is not enough to simply make climate change scenarios available. Their provision must be accompanied by ongoing guidance and support to ensure widespread and appropriate uptake. Second, on-going dialogue between those providing scenarios and the communities using them is fundamental to constructively meet the challenges associated with delivering credible scenarios that balance user requirements and expectations with what the science can deliver.  相似文献