Characterizing frictional behavior for use in predicting the seismic response of unattached equipment

Characterizing friction is a fundamentally important aspect of modeling the seismic response of a body resting on any mechanical interface. In the context of rigid bodies mounted within building structures, the numerous types of elements and interfaces encountered in practice require specific characterization before any modeling assumptions can be undertaken. To this end, in this paper, the specific problem of characterizing the frictional behavior for a variety of small equipment types typically found in Biological and Chemical Science laboratories is studied using two different methods of testing. A simple approach is presented to determine the instantaneous coefficients of friction considering inertial effects. Resulting coefficients of static friction μ_s and kinetic friction μ_k for these types of equipment and their plausible range of uncertainty are presented. Analytical comparisons with shake table experiments, using mean frictional resistance values, illustrate that reasonable estimations of time history response can be determined. The accuracy of the prediction increases as the effects of stick-slip are minimized.     

Relationships among remotely sensed soil moisture,precipitation and landslide events

Landslides are triggered by earthquakes, volcanoes, floods, and heavy continuous rainfall. For most types of slope failure, soil moisture plays a critical role because increased pore water pressure reduces the soil strength and increases stress. However, in-situ soil moisture profiles are rarely measured. To establish the soil moisture and landslide relationship, a qualitative comparison among soil moisture derived from AMSR-E, precipitation from TRMM and major landslide events was conducted. This study shows that it is possible to estimate antecedent soil moisture conditions using AMSR-E and TRMM satellite data in landslide prone areas. AMSR-E data show distinct annual patterns of soil moisture that reflect observed rainfall patterns from TRMM. Results also show enhanced AMSR-E soil moisture and TRMM rainfall prior to major landslide events in landslide prone regions of California, U.S.; Leyte, Philippines; and Dhading, Nepal.     

Experimental constraints on pre-eruption conditions of pantelleritic magmas: Evidence from the Eburru complex, Kenya Rift

The phase relationships and compositions of a pantellerite from the Eburru complex in the Kenya Rift Valley have been determined at 150 MPa and under reducing conditions, 2 log units below the Ni–NiO solid buffer. The effects of temperature and melt water content on phase relationships have been explored. Alkali feldspar and quartz crystallise alone at temperatures above 700 °C, irrespective of melt water content. Below 700 °C, sodic amphibole and clinopyroxene also crystallise; the amphibole being the liquidus phase under water-rich conditions. The coexistence of amphibole phenocrysts with alkali feldspar and quartz in a crystal-poor pantellerite implies temperatures below 700 °C and melt water contents higher than 4 wt.%, possibly up to 5–6 wt.%. Pantellerites have lower liquidus temperatures than associated comendites, which supports a parent–daughter relationship between the two magma types. The melts produced in the experiments extend the compositional trend displayed by the natural rock series, and reproduce some extreme compositions occasionally observed in alkaline volcanic series, with FeO contents above 12 wt.% and Na₂O contents approaching 10 wt.%. Pantellerites are therefore the true near-minimum melt compositions of alkaline oversaturated magma series.     

Satellite imagery activism: Sharpening the focus on tropical deforestation

Since the first land remote sensing satellite was launched in the early 1970s, government agencies, private companies and research institutions have used satellite imagery data for a growing range of civil and commercial applications focused on natural resource management and exploitation, and environmental monitoring. The global diffusion of remote sensing expertize, along with growing public access to satellite images, has created conditions for improving levels of global transparency. One aspect of this global transparency is the advent of new users of imagery data – or 'imagery activists'– including, among others, issue-oriented nongovernmental organizations (NGOs), media groups, multinational organizations and academic researchers who now are able to access satellite imagery in order to draw domestic and international attention to particular public policy concerns. This paper broadly surveys the contemporary phenomenon of satellite imagery activism and outlines the main challenges facing imagery activists, particularly in relation to deforestation and other forest monitoring issues.     

The structural and geochemical evolution of the Singhbhum granite batholithic complex, India

The Singhbhum granite batholithic complex of eastern India is composed mainly of (a) the Older Metamorphic Group, tonalite (-trondhjemite) gneiss (OMTG, 3800 Ma old), whch intruded synkinematically into the enveloping Older Metamorphic Group (OMG, > 3800 Ma old) and (b) the Singhbhum granite (SBG) consisting of three distinct but closely related phases of at least twelve separate magmatic units of granodiorite-granite (2950 Ma old), and a number of patches of granitised OMG orthoamphibolites. Geochemical studies including REE and LIL elements suggest that (a) the OMG orthoamphibolites were derived either by re-melting of a K-poor basalt (LKT) or of mantle peridotite with high concentration of LIL elements, (b) the OMG tonalite was derived by partial melting of amphibolite and (c) the Singhbhum granite magmas appear to have formed in two distinct modes: (i) partial melting of amphibolite for the magmas of phases I and II and (ii) partial melting of a siliceous, garnet-bearing granulite for magmas of the phase III units.     

An ion microprobe study of the partitioning of trace elements between clinopyroxene and liquid in the system diopside-albite-anorthite

The partitioning of trace elements (Sc, Ti, Sr and Sm) between diopsidic clinopyroxene and liquid was studied experimentally in the system diopside-albite-anorthite at 1250°C, 1300°C and 1345°C at 1 atm. Twelve different bulk compositions were selected to study the effects of temperature and chemical composition. A Cameca ion microprobe was used to determine trace element concentrations in both clinopyroxene and liquid. Experiments of different run duration $\text{1}\text{4}\text{8}\text{?}$ days) showed that equilibrium was approached in less than 4 days at 1275°C. Equilibrium was also evaluated by a reversal run. A series of runs of constant bulk composition but with variable trace element contents showed that Henry's Law was obeyed over concentration ranges of the trace elements similar to those encountered in natural systems. The partition coefficients show significant ranges: Sc, 0.345~2.61; Ti, 0.084~0.214; Sr, 0.075~0.136; Sm, 0.054~0.328; the values are comparable with those obtained experimentally by other investigators. The partition coefficients vary as a function of both temperature and chemical composition. The experimental results are discussed in terms of exchange equilibria using the Bottinga-Weill silicate melt model. It is demonstrated that analytical uncertainties of both major and trace elements play an important role in understanding trace element exchange equilibria; propagation of analytical errors in the thermodynamic treatment is equally important.     

Cadmium in tissues of lobsters captured near a lead smelter

Cadmium distribution among tissues of lobsters (Homarus americanus) from Belledune Harbour near a lead smelter was determined and compared with that of lobsters from uncontaminated areas of Stonehaven, N.B., Canada and from Maine, USA. The hepatopancreas contained more than 90% of the body burden of cadmium. High concentrations of cadmium were also present in green glands and gills. Cadmium concentrations in the hepatopancreas, gills, and green glands were correlated with the concentrations in most of the other tissues.     

A spatial and temporal drought risk assessment of three major tree species in Britain using probabilistic climate change projections

Probabilistic climate data have become available for the first time through the UK Climate Projections 2009, so that the risk of change in tree growth can be quantified. We assessed the drought risk spatially and temporally using drought probabilities calculated from the weather generator data and tree species vulnerabilities using Ecological Site Classification model across Britain. We evaluated the drought impact on the potential yield class of three major tree species (Picea sitchensis, Pinus sylvestris, and Quercus robur), which cover around 59 % (400,700 ha) of state-managed forests, across the lowlands and uplands. We show that drought impacts result mostly in reduced tree growth over the next 80 years when using B1, A1B, and A1FI IPCC emissions scenarios, but varied spatially. We found a maximum reduction of 94 % but also a maximum increase of 56 % in potential stand yield class in the 2080s from the baseline climate (1961–1990). Furthermore, potential production over the state-managed forests for all three species in the 2080s is estimated to decrease due to drought by 42 % in the lowlands and by 32 % in the uplands in comparison to the baseline climate. Our results reveal that potential tree growth and forest production on the state-managed forests in Britain is likely to reduce, and indicate where and when adaptation measures are required. Moreover, this paper demonstrates the value of probabilistic climate projections for an important economic and environmental sector.