Diagenetically induced shear failure of fine-grained sediments and the development of polygonal fault systems   总被引：1，自引：0，他引：1  

Joe Cartwright 《Marine and Petroleum Geology》2011,28(9):1593-1610

Polygonal fault systems (PFS) are widely developed along many continental margin basins and some interior cratonic and foreland basins. They are networks of small normal faults that are usually found in tiers which are crudely layer-bound successions consisting mainly of fine-grained sediments. Their origin has been widely debated with explanations ranging from dewatering of overpressured layers to gravitational loading under fixed lateral boundary conditions. Their distribution in fine-grained intervals suggests that their genesis is connected to their initial lithology. Recent experimental work suggests that diagenesis of clay-rich sediments can lead to shear failure under low confining stresses. This explanation accords well with all subsurface observations of PFS made to date, and seems the most likely mechanism to explain their genesis. This diagenetic mode of shear fracturing in fine-grained sediments could be much more prevalent than in polygonal fault systems alone, and this has significant implications for shale gas exploration, CO₂ sequestration and exploration for methane hydrates.  相似文献   

Toxicity comparison of biosurfactants and synthetic surfactants used in oil spill remediation to two estuarine species   总被引：1，自引：0，他引：1  

Edwards KR  Lepo JE  Lewis MA 《Marine pollution bulletin》2003,46(10):1309-1316

The relative environmental toxicities of synthetic and biogenic surfactants used in oil spill remediation efforts are not well understood. Acute and chronic toxicities of three synthetic surfactants and three microbiologically produced surfactants were determined and compared in this study for the estuarine epibenthic invertebrate, Mysidopsis bahia and the inland silverside, Menidia beryllina. The toxicities of the surfactant were determined in standard laboratory static and static-renewal tests of 4-7 d duration. Results were specific to the surfactant, response parameter and test species. The LC50 values (nominal concentrations) for M. bahia ranged from 3.3 mg/l (Triton X-100) to >1000 mg/l (PES-61) and 2.5 mg/l (Triton X-100) to 413.6 mg/l (PES-61) for M. beryllina. Chronic first-effect concentrations (mg/l) for the six surfactants ranged from 2.3 to 465.0 (M. beryllina) and 1.0 to >1000.0 (M. bahia) based on reductions in growth and fecundity. Few generalizations could be made concerning the results due to their variability but M. bahia was generally the more sensitive species and the toxicities of the biosurfactants were intermediate to those of the synthetic surfactants.  相似文献   

Personalizing map content to improve task completion efficiency     

David Wilson  Michela Bertolotto  Joe Weakliam 《International journal of geographical information science》2013,27(5):741-760

Significant interaction challenges arise in both developing and using interactive map applications. Users encounter problems of information overload in using interactive maps to complete tasks. This is further exacerbated by device limitations and interaction constraints in increasingly popular mobile platforms. Application developers must then address restrictions related to screen size and limited bandwidth in order to effectively display maps on mobile devices. In order to address issues of user information overload and application efficiency in interactive map applications, we have developed a novel approach for delivering personalized vector maps. Ongoing task interactions between users and maps are monitored and captured implicitly in order to infer individual and group preferences related to specific map feature content. Personalized interactive maps that contain spatial feature content tailored specifically to users' individual preferences are then generated. Our approach addresses spatial information overload by providing only the map information necessary and sufficient to suit user interaction preferences, thus simplifying the completion of tasks performed with interactive maps. In turn, tailoring map content to specific user preferences considerably reduces the size of vector data sets necessary to transmit and render maps on mobile devices. We have developed a geographic information system prototype, MAPPER (MAP PERsonalization), that implements our approach. Experimental evaluations show that the use of personalized maps helps users complete their tasks more efficiently and can reduce information overload.  相似文献   

Non-standard structure formation scenarios     

Alexander Knebe  Brett Little  Ranty Islam  Julien Devriendt  Asim Mahmood  Joe Silk 《Astrophysics and Space Science》2003,284(2):335-340

Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by introducing self-interacting cold dark matter particles to a tuning of complex astrophysical processes such as global and/or local feedback. All these efforts attempt to soften density profiles and reduce the abundance of satellites in simulated galaxy halos. In this contribution we are exploring the differences between a Warm Dark Matter model and a CDM model where the power on a certain scale is reduced by introducing a narrow negative feature (`dip'). This dip is placed in a way so as to mimic the loss of power in the WDM model: both models have the same integrated power out to the scale where the power of the Dip model rises to the level of the unperturbed CDM spectrum again. Using N-body simulations we show that that the new Dip model appears to be a viable alternative to WDM while being based on different physics: where WDM requires the introduction of a new particle species the Dip stems from anon-standard inflationary period. If we are looking for an alternative to the currently challenged standard ΛCDM structure formation scenario, neither the ΛWDM nor the new Dip model can be ruled out with respect to the analysis presented in this contribution. They both make very similar predictions and the degeneracy between them can only be broken with observations yet to come. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

The physics of particle acceleration at the heliospheric termination shock     

J.R. Jokipii  Joe Giacalone  Jozsef Kta 《Planetary and Space Science》2007,55(15):2267-2272

Cosmic rays are ubiquitous in space, and the essential similarity of their energy spectra in many different regions places significant general constraints on the mechanisms for their acceleration and confinement. Diffusive shock acceleration is at present the most successful acceleration mechanism proposed, and, together with transport in Kolmogorov turbulence, can account for the universal specta. A unique laboratory for studying the acceleration and transport of charged particles is the outer heliosphere, including the solar wind termination shock and heliosheath.

A widely accepted paradigm for the transport and acceleration of energetic particles in the heliosphere has evolved over the last few decades. This picture has successfully explained many features of the modulation of galactic cosmic rays and the transport and acceleration of anomalous cosmic rays at the solar-wind termination shock. Recent Voyager observations near and beyond the termination shock have revealed new, and in some cases, unexpected phenomena which have led to questions concerning the established paradigm. The physical interpretation of the observations requires a blunt termination shock, rapid inward motion of the shock and temporal variations over time scales ranging from hours to 22 years. Incorporation of these into the physics has promise of explaining most, if not, all of the observed phenomena while retaining the advantages of the termination shock paradigm for both galactic and anomalous cosmic rays.  相似文献   

Cartophilias and cartoneuroses   总被引：2，自引：0，他引：2  

Joe Painter 《Area》2006,38(3):345-347

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Jupiter: The planet,satellites and magnetosphere: edited by Fran Bagenal,Timothy E. Dowling,and William McKinnon     

Joe Giacalone 《Meteoritics & planetary science》2005,40(2):329-330

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Experimental and modelling investigations of the biogeochemistry of gas production from low and intermediate level radioactive waste     

Joe Small  Mikko Nykyri  Mika Helin  Ulla Hovi  Tuija Sarlin  Merja Itävaara 《Applied Geochemistry》2008

The degradation of organic wastes and the corrosion of metallic wastes and steel containers in low and intermediate level radioactive waste (LLW/ILW) repositories are important processes that affect repository geochemistry and the speciation and transport of radionuclides. Gas is generated in association with these degradation processes and this has the potential to overpressure the repository, which can promote transport of groundwater and gas, and consequently radionuclide transport. Microbial activity plays an important role in organic degradation, corrosion and gas generation through the mediation of reduction–oxidation reactions.  相似文献   

The king city operational doppler radar: Development,all‐season applications and forecasting     

C.L. Crozier  P.I. Joe  J.W. Scott  H.N. Herscovitch  T.R. Nichols 《大气与海洋》2013,51(3):479-516

Abstract

In 1985, the first Doppler weather radar to operate in Canada was established by the Research Directorate of the Atmospheric Environment Service (AES) at a site in King City, north of Toronto, Ontario. The initial thrust of the research program immediately recognized the advances Doppler observations would make in the operational sector and a system was devised to satisfactorily meet both needs. This paper describes the radar system, the techniques, the data processing and innovations developed to provide immediate intelligence to the data. The system was developed by adapting mainly commercial hardware and in‐house software. The system factors that are significant for operational meteorological surveillance and analysis, the display form and formats, and the sample cases illustrating the impact of Doppler observations on both synoptic and mesocale analysis in all seasons complete the discussion.

Significant factors, in both system parameters and meteorology, that impinge on the success of the Doppler radar program and its applications are summarized. There is sufficient maturity in the technology, display capabilities and meteorological knowledge to warrant network implementation. However, research and development is still needed to interpret and synthesize the voluminous amounts of available information. In particular, conceptual models of the kinematics of mesoscale systems need considerable development.  相似文献   

Establishing boundary classes for the classification of UK marine waters using phytoplankton communities   总被引：2，自引：0，他引：2  

Devlin M  Best M  Coates D  Bresnan E  O'Boyle S  Park R  Silke J  Cusack C  Skeats J 《Marine pollution bulletin》2007,55(1-6):91-103

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