Sample records for barberton greenstone belt

  1. Polyphase thrust tectonic in the Barberton greenstone belt (United States)

    Paris, I. A.


    In the circa 3.5 by-old Barberton greenstone belt, the supracrustal rocks form a thick and strongly deformed thrust complex. Structural studies in the southern part of the belt have shown that 2 separate phases of over-thrusting (D sub 1 and D sub 2) successively dismembered the original stratigraphy. Thrust nappes were subsequently refolded during later deformations (D sub 3 and D sub 4). This report deals with the second thrusting event which, in the study region appears to be dominant, and (unlike the earlier thrusting), affects the entire supracrustal pile. The supracrustal rocks form a predominantly NE/SW oriented, SE dipping tectonic fan (the D sub 2 fan) in which tectonic slices of ophiolitic-like rocks are interleaved with younger sedimentary sequences of the Diepgezet and malalotcha groups. Structural and sedimentological data indicate that the D sub 2 tectonic fan was formed during a prolonged, multi-stage regional horizontal shortening event during which several types of internal deformation mechanisms were successively and/or simultaneously active. Movement appears to have been predominantly to the NW and to the N. During D sub 2, periods of quiescence and sedimentation followed periods of thrust propagation. Although the exact kinematics which led to the formation of this fan is not yet known, paleoenvironmental interpretations together with structural data suggest that D sub 2 was probably related to (an) Archean collision(s).

  2. Archaean greenstone belt tectonism and basin development: some insights from the Barberton and Pietersburg greenstone belts, Kaapvaal Craton, South Africa (United States)

    de Wit, Maarten J.

    The sediments in two of South Africa's major Archaean greenstone belts, the Barberton and Pietersburg greenstone belts, span an age range of some 800 million years. Both greenstone belts represent remnants of extensive fold and thrust belts with complex, but different polyphase tectonic histories. The oldest sediments were deposited between circa 3470 and 3490 M.a. on oceanic like crust preserved in the Barberton belt, possibly at the same time as sedimentation on similar oceanic crust preserved in the Pietersburg belt. Thereafter, the geologic evolution of these two belts diverged considerably. In the Barberton belt, there is clear evidence that the oceanic crust and sediments were obducted onto an intra-arc basin environment within 50 million years of its formation. The sequence was later further imbricated by northwest directed thrust stacking between 3300-3200 M.a. Basin development during both periods of thrusting took place in close proximity to active "calc-alkaline" arc systems. Deformation of the sediments within these basins took place while the same sediments were being deposited. Sedimentation took place predominantly in subaqueous environments, ranging from submarine mid-fans below the photic zone to tidal flats and deltaic plains. The sediments represent a polyhistory successor-type basin: early basins developed along a complex subduction related plate boundary; these basins later evolved into foreland depositories along and within collisional environments of an accretionary orogen. Late in the history of the Barberton greenstone belt (circa 3100 M.a.), the rocks were in places thermally reactivated and probably subjected to extensional processes; these processes overlapped in time with the main episodes of economic gold mineralization, and are of "early Witwatersrand-basin" age. The oceanic-like crust (including associated sediments) preserved in the Pietersburg belt was not significantly deformed until at least 500 million years after its formation

  3. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa (United States)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.


    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  4. The stratigraphy of the 3.5-3.2 Ga Barberton Greenstone Belt revisited: A single zircon ion microprobe study

    International Nuclear Information System (INIS)

    Recent field and geochemical studies indicate a need to test the stratigraphy of the ca. 3.5 Ga Barberton Greenstone Belt as it is presently adopted. This work uses the ion microprobe SHRIMP, to attempt such a test. Results show that: (1) Volcaniclastic sediments of the Theespruit Formation (<3453±6 Ma) could be younger than the (structurally) overlying mafic and ultramafic volcanics of the Komati Formation (3482±5 Ma). A major structural discontinuity may therefore exist between the two formations. (2) An age of 3538±6 Ma established for a tectonic wedge of tonalitic gneiss within the Theespruit Formation confirms the presence of a sialic basement and deformed unconformity below that unit. The tonalitic gneiss is the oldest unit yet recorded within the greenstone belt, equal in age to the older components of the adjacent Ancient Gneiss Complex. (3) The interpreted ages of felsic volcanic rocks from both the Hooggenoeg (3445±8 Ma) and Theespruit Formations and the nearby Theespruit Pluton (3437±6 Ma) are essentially the same, and corroborate field and geochemical evidence that the felsic units were probably cogenetic and emplaced simultaneously as high-level equivalents of trondjhemite-tonalite plutons that intrude the greenstone belt at its southwestern extremity. (4) Felsic-intermediate volcanic-volcaniclastic rocks locally separating the two major groups (the Fig Tree and Moodies Groups) which overlie the Onverwacht Group record a second major peak of tonalitic magmatism in the Barberton terrain at about 3250 Ma. This is close to the age of the Kaap Valley tonalite pluton which intrudes the Barberton Greenstone Belt at ca. 3226 Ma along its northwestern margin. The present results indicate the Barberton Greenstone Belt is part of an allochthonous sequence containing major tectonic and stratigraphic breaks, with a protracted history; of which the last 200 million years, at least, evolved within a tectonically active convergent environment. (orig.)

  5. The rheological behaviour of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa


    M. Ledevin; Arndt, N.; Davaille, A.; Ledevin, R.; Simionovici, A.


    In the Barberton Greenstone Belt, South Africa, a 100–250 m thick complex of carbonaceous chert dikes marks the transition from the Mendon Formation to the Mapepe Formation (3260 Ma). The sub-vertical- to vertical position of the fractures, the abundance of highly shattered zones with poorly rotated angular fragments and common jigsaw fit, radial structures, and multiple injection features point to repetitive hydraulic fracturing that released overpressured fluids trapped wi...

  6. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa


    M. Ledevin; Arndt, N.; Simionovici, A.


    A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average) and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at...

  7. Early terrestrial impact events: Archean spherule layers in the Barberton Greenstone Belt, South Africa (United States)

    Ozdemir, Seda; Koeberl, Christian; Schulz, Toni; Reimold, W. Uwe; Hofmann, Axel


    In addition to the oldest known impact structure on Earth, the 2.02-billion-year-old Vredefort Structure in South Africa, the evidence of Early Earth impact events are Archean spherule beds in South Africa and Australia. These spherules have been interpreted as condensation products from impact plumes and molten impact ejecta or/and impact ejecta that were melted during atmospheric re-entry [e.g., 1,2]. The 3.2-3.5 Ga spherule layers in the Barberton Greenstone Belt in South Africa currently represent the oldest known remnants of impact deposits on Earth. Aiming at identification of extraterrestrial components and to determine the diagenetic and metamorphic history of spherule layer intersections recently recovered in the CT3 drill core from the northeastern part of the Barberton Greenstone Belt, we have studied samples from these layers in terms of petrography and geochemistry. All samples, including spherule layer intersections and intercalating country rocks, were studied for mineral identification by optical and electron microscopy, as well as electron microprobe analysis (EPMA) at Natural History Museum Vienna and Museum für Naturkunde Berlin (MfN). Major and trace element compositions were determined via X-ray fluorescence spectrometry at MfN and instrumental neutron activation analysis (INAA) at University of Vienna. Os isotopes were measured by thermal ionization mass spectrometry (N-TIMS) at University of Vienna. Eighteen spherule beds are distributed over 150 meter drill core in CT3. Spherules are variably, deformed or undeformed. The high number of these layers may have been caused by tectonic duplication. Spherule beds are intercalated with shale, chert, carbonate, and/or sulfide deposits (country rocks). The size range of spherules is 0.5 to 2 mm, and some layers exhibit gradation. Shapes of spherules differ from spherical to ovoid, as well as teardrops, and spherules commonly show off-center vesicles, which have been interpreted as a primary

  8. Palaeoarchean Barite Deposits in the Barberton Greenstone Belt: Origin and Links to Early Microbial Life (United States)

    Mason, P. R.; Peters, A.; Nijman, W.; Reimer, T. O.; Whitehouse, M. J.


    Barite deposits are considered important for identifying microbial S cycling in Archean rocks since they can provide information about S isotopes in coexisting sulfate and sulfide minerals. However the degree to which barite and pyrite in metasedimentary rocks are related remains unclear. In this study we have investigated the origin of barite and pyrite in four main horizons seen in both outcrop and fresh drill core material from the Lower Mapepe formation (3.26 to 3.23 Ga), Barberton Greenstone Belt, South Africa. Host rocks include shales, cherts, tuffs and conglomerates that are variably silicified and/or affected by carbonate alteration. The high-energy depositional environment of the host rocks, mineralogical textures, barite chemistry and the occurrence of feldspars from the rarely-found celsian-hyalophane-orthoclase series suggest a seafloor exhalative origin for the barite. In contrast pyrite is closely associated with cherts and dolomitic units where rare earth element and Y data support a marine influence. Pyrite chemistry (Co/Ni= 0.1-1, Se/S <5 x 10- 5) also indicates a low temperature sedimentary origin. Multiple S isotope data (32S, 33S, 34S, determined by SIMS) for pyrite indicates a number of arrays with limited δ34S fractionation at constant Δ33S associated with individual syn-sedimentary microcrystalline pyrite layers. Isolated euhedral pyrites in massive chert and barite rich units show much more scatter and larger degrees of Δ33S variation (-1 to +4 ). Our results are consistent with models invoking microbial mass dependent fractionation of a heterogeneous elemental sulfur source derived from atmospheric photolysis. The sulfate reservoir can also be linked to photolysis but there is no clear relationship between the barite and pyrite S isotope data, suggesting that microbial (or abiotic) sulfate reduction was absent at this time or that the basinal sulfate concentration must have remained significantly lower than the mM level prior to barite

  9. Extensional tectonics during the igneous emplacement of the mafic-ultramafic rocks of the Barberton greenstone belt (United States)

    Dewit, M. J.


    The simatic rocks (Onverwacht Group) of the Barberton greenstone belt are part of the Jamestown ophiolite complex. This ophiolite, together with its thick sedimentary cover occupies a complex thrust belt. Field studies have identified two types of early faults which are entirely confined to the simatic rocks and are deformed by the later thrusts and associated folds. The first type of fault (F1a) is regional and always occurs in the simatic rocks along and parallel to the lower contacts of the ophiolite-related cherts (Middle Marker and equivalent layers). These fault zones have previously been referred to both as flaser-banded gneisses and as weathering horizons. In general the zones range between 1-30m in thickness. Displacements along these zones are difficult to estimate, but may be in the order of 1-100 km. The structures indicate that the faults formed close to horizontal, during extensional shear and were therefore low angle normal faults. F1a zones overlap in age with the formation of the ophiolite complex. The second type of faults (F1b) are vertical brittle-ductile shear zones, which crosscut the complex at variable angles and cannot always be traced from plutonic to overlying extrusive (pillowed) simatic rocks. F1b zones are also apparently of penecontemporaneous origin with the intrusive-extrusive igneous processs. F1b zones may either represent transform fault-type activity or represent root zones (steepened extensions) of F1a zones. Both fault types indicate extensive deformation in the rocks of the greenstone belt prior to compressional overthrust tectonics.

  10. The rheological behavior of fracture-filling cherts: example from Barite Valley dikes, Barberton greenstone Belt, South Africa. (United States)

    Ledevin, Morgane; Arndt, Nicholas; Simionovici, Alexandre


    A 100m-thick complex of black carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the chert dikes (ca. 1m on average) and by the abundance of completely shattered rocks. Similar structures occur in many greenstones worldwide. Here we investigate (1) the origin of the dikes and (2) the nature of the material that precipitated to form the fracture-filling chert. The dike-and-sill organization of the plumbing system and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the fractures, a particularity attributed to the confinement of the hydrothermal system below an impermeable cape of chert. The location of the dikes beneath an impact spherule bed leads us to propose that the hydrothermal circulation was related to the impact. The present site may have been located at the external margin of a large crater. The geometry of the dikes and the petrography of the cherts indicate that the fluid that invaded the fractures was thixotropic. The injection of black chert into extremely fine fractures is evidence oflow viscosity at the time of injection while the lack of closure of larger veins below eroded country blocks and the suspension of fragments in a chert matrix provides evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a fluid. The presence of abundant clay-sized particles of silica

  11. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

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    M. Ledevin


    Full Text Available A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the

  12. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa (United States)

    Ledevin, M.; Arndt, N.; Simionovici, A.


    A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average) and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the veins. Stirring and

  13. Texture-specific Si isotope variations in Barberton Greenstone Belt cherts record low temperature fractionations in early Archean seawater (United States)

    Stefurak, Elizabeth J. T.; Fischer, Woodward W.; Lowe, Donald R.


    Sedimentary cherts are unusually abundant in early Archean (pre-3.0 Ga) sequences, suggesting a silica cycle that was profoundly different than the modern system. Previously applied for the purpose of paleothermometry, Si isotopes in ancient cherts can offer broader insight into mass fluxes and mechanisms associated with silica concentration, precipitation, diagenesis, and metamorphism. Early Archean cherts contain a rich suite of sedimentological and petrographic textures that document a history of silica deposition, cementation, silicification, and recrystallization. To add a new layer of insight into the chemistry of early cherts, we have used wavelength-dispersive spectroscopy and then secondary ion mass spectrometry (SIMS) to produce elemental and Si and O isotope ratio data from banded black-and-white cherts from the Onverwacht Group of the Barberton Greenstone Belt, South Africa. This geochemical data is then interpreted in the framework of depositional and diagenetic timing of silica precipitation provided by geological observations. SIMS allows the comparison of Si and O isotope ratios of distinct silica phases, including black carbonaceous chert beds and bands (many including well-defined sedimentary grains), white relatively pure chert bands including primary silica granules, early cavity-filling cements, and later quartz-filled veins. Including all chert types and textures analyzed, the δ30Si dataset spans a range from -4.78‰ to +3.74‰, with overall mean 0.20‰, median 0.51‰, and standard deviation 1.30‰ (n = 1087). Most samples have broadly similar δ30Si distributions, but systematic texture-specific δ30Si differences are observed between white chert bands (mean +0.60‰, n = 750), which contain textures that represent primary and earliest diagenetic silica phases, and later cavity-filling cements (mean -1.41‰, n = 198). We observed variations at a ∼100 μm scale indicating a lack of Si isotope homogenization at this scale during

  14. Compositional Grading in an Impact-produced Spherule Bed, Barberton Greenstone Belt, South Africa: A Key to Condensation History of Rock Vapor Clouds (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.


    The chemical and physical processes by which spherules form during the condensation of impact-produced rock vapor clouds are poorly understood. Although efforts have been made to model the processes of spherule formation, there is presently a paucity of field data to constrain the resulting theoretical models. The present study examines the vertical compositional variability in a single early Archean spherule bed in the Barberton Greenstone Belt (BGB), South Africa, in order to better identify the process by which impact vapor clouds condense and spherules form and accumulate. The BGB spherule beds are suitable for this type of study because of their great thickness, often exceeding 25cm of pure spherules, due to the massive sizes of the impactors. Two main problems complicate analysis of vertical compositional variability of graded spherule beds: (1) differential settling of particles in both the vapor and water column due to density and size differences and (2) turbulence within the vapor cloud. The present study compares sections of spherule bed S3 from four different depositional environments in the Barberton Greenstone Belt: (1) The Sheba Mine section (SAF-381) was deposited under fairly low energy conditions in deep water, providing a nice fallout sequence, and also has abundant Ni-rich spinels; (2) Jay's Chert section (SAF-380) was deposited in subaerial to shallow-water conditions with extensive post-depositional reworking by currents. The spherules also have preserved spinels; (3) the Loop Road section (loc. SAF-295; samp. KSA-7) was moderately reworked and has only rare preservation of spinels; and (4) the shallow-water Barite Syncline section (loc. SAF-206; samp KSA-1) has few to no spinels preserved and is not reworked. Although all of the spherule beds have been altered by silica diagenesis and K-metasomatism, most of the compositional differences between these sections appear to reflect their diagenetic histories, possibly related to their differing

  15. Inferred Primary Compositions of Archean Spherules Formed by the Condensation of an Impact-produced Rock Vapor Cloud, Barberton Greenstone Belt, South Africa (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.


    Based on the lunar cratering record, impacts were larger and more frequent on the early Earth than they are today. There is no persevered record of these early terrestrial impacts because rocks of this age have been obliterated by tectonism and erosion. The oldest known evidence of impacts on Earth lies in four beds (S1, S2, S3 and S4) in the Barberton Greenstone Belt (BGB), South Africa, ranging in age from about 3.24 to 3.47 Ga. These beds are composed in large part of sand-sized spherical particles, termed spherules, that are thought to have formed by the condensation of rock vapor clouds ejected above the atmosphere as a result of large impacts. Spherule beds S2 and S3 are both about 20 cm thick where composed entirely of fall-deposited spherules and up to a meter thick where spherules are mixed with locally derived debris. The diameters the bolides have been estimated to be between 20 and 50 km, based on bed thickness, size of the largest spherules, Ir fluence and extraterrestrial Cr.

  16. Physics of crustal fracturing and chert dike formation triggered by asteroid impact, ˜3.26 Ga, Barberton greenstone belt, South Africa (United States)

    Sleep, Norman H.; Lowe, Donald R.


    asteroid impacts, reflected in the presence of spherule beds in the 3.2-3.5 Ga Barberton greenstone belt (BGB), South Africa, generated extreme seismic waves. Spherule bed S2 provides a field example. It locally lies at the contact between the Onverwacht and Fig Tree Groups in the BGB, which formed as a result of the impact of asteroid (possibly 50 km diameter). Scaling calculations indicate that very strong seismic waves traveled several crater diameters from the impact site, where they widely damaged Onverwacht rocks over much of the BGB. Lithified sediments near the top of the Onverwacht Group failed with opening-mode fractures. The underlying volcanic sequence then failed with normal faults and opening-mode fractures. Surficial unlithified sediments liquefied and behaved as a fluid. These liquefied sediments and some impact-produced spherules-filled near-surface fractures, today represented by swarms of chert dikes. Strong impact-related tsunamis then swept the seafloor. P waves and Rayleigh waves from the impact greatly exceeded the amplitudes of typical earthquake waves. The duration of extreme shaking was also far longer, probably hundreds of seconds, than that from strong earthquakes. Dynamic strains of ˜10-3 occurred from the surface and downward throughout the lithosphere. Shaking weakened the Onverwacht volcanic edifice and the surface layers locally moved downhill from gravity accommodated by faults and open-mode fractures. Coast-parallel opening-mode fractures on the fore-arc coast of Chile, formed as a result of megathrust events, are the closest modern analogs. It is even conceivable that dynamic stresses throughout the lithosphere initiated subduction beneath the Onverwacht rocks.

  17. Carbonaceous matter and putative microfossils of the mid-Archean Kromberg type-section re-visited, Barberton Greenstone Belt, South Africa (United States)

    McLoughlin, Nicola; Grosch, Eugene


    Silicified seafloor sediments of the Kromberg Formation from the Onverwacht Group of the Barberton greenstone belt (BGB), South Africa, have been argued to contain some of the world's oldest preserved carbonaceous microfossils. Previous studies of these cherts have reported filamentous, spheroidal and ellipsoidal microfossils in thin-section (Walsh 1992); and bacteriomorph like structures in HF-etched samples (Westall et al. 2001). These microtextural studies however, lack supporting in-situ geochemical data, and are hampered to some degree by re-mobilisation of the carbonaceous matter (Van Zuilen et al. 2007). In light of these concerns, and ongoing debates surrounding carbonaceous remains in other Archean cherts (e.g., W Australia), further in-situ data from the Kromberg is required to positively identify carbonaceous matter of biogenic origin. New data will also help to address outstanding questions regarding the relative contribution of benthic versus planktonic microorganisms, and the putative microbial metabolisms involved. This study focuses on surface samples and drill core from the Barberton Scientific Drilling Programme, (BSDP, Grosch et al. 2009) from the southeastern limb of the Onverwacht anticline of the BGB. We sampled the Footbridge chert and a second chert horizon in drill core KD1 of the BSDP in the upper Kromberg Fm; and surface outcrops of two black cherts from the lower Kromberg Fm. Sedimentological logging reveals horizons rich in volcaniclastics with interbedded finely laminated grey-black chert, also intrusive black cherts, and sulphide rich horizons. The TOC of the sampled cherts is 1.24 to 5.40 wt%. Preliminary bulk carbon isotope values range from δ13C -21.1 to -35.3o values that are consistent with organic matter produced by anoxygenic photosynthesis. Microfabrics preserved in the Kromberg cherts include, primary wispy-laminated carbonaceous films suggesting compaction of early carbonaceous laminae. Also large composite carbonaceous

  18. Spherule Beds 3.47-3.24 Billion Years Old in the Barberton Greenstone Belt, South Africa: A Record of Large Meteorite Impacts and Their Influence on Early Crustal and Biological Evolution (United States)

    Lowe, Donald R.; Byerly, Gary R.; Kyte, Frank T.; Shukolyukov, Alexander; Asaro, Frank; Krull, Alexander


    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approx. 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record.

  19. Chronology of early Archaean granite-greenstone evolution in the Barberton Mountain Land, South Africa, based on precise dating by single zircon evaporation (United States)

    Kruener, Alfred; Byerly, Gary R.; Lowe, Donald R.


    Precise Pb-207/Pb-206 single zircon evaporating ages are reported for low-grade felsic metavolcanic rocks within the Onverwacht and Fig Tree Groups of the Barberton Greenstone Belt (BGB), South Africa, as well as for granitoid plutons bordering the belt. Dacitic tuffs of the Hooggenoeg Formation in the upper part of the Onverwacht Group are shown to yield ages between 3445 + or - 3 and 3416 + or - 5 Ma and to contain older crustal components represented by a 3504 + or - 4 Ma old zircon xenocryst. Fig Tree dacitic tuffs and agglomerates have euhedral zircons between 3259 + or - 3 Ma in age which are interpreted to reflect the time of crystallization. The comagmatic relationships between greenstone felsic volcanic units and the surrounding plutonic suites are keynoted. The data adduced show that the Onverwacht and Fig Tree felsic units have distinctly different ages and thus do not constitute a single, tectonically repeated unit as proposed by others. It is argued that conventional multigrain zircon dating may not accurately identify the time of felsic volcanic activity in ancient greenstones, and that the BGB in the Kaapval craton of southern Africa and greenstones in the Pilbara Block of Western Australia may have been part of a larger crustal unit in early Archaean times.

  20. Review of tungsten mineralisation in greenstone belts in the eastern and north-eastern Transvaal

    International Nuclear Information System (INIS)

    Tungsten (scheelite) mineralisation is known to occur, occasionally as noteworthy deposits, in the Swazian greenstone belts in the Eastern and North-Eastern Transvaal. An outline and description are given of all known scheelite occurrence in the Sutherland and Murchison Ranges and possibilities of finding such mineralisation in the Barberton greenstone belt are described. Scheelite deposits in these environments: (i) are commonly associated with gold and/or antimony mineralisation; (ii) although found in a variety of host types, commonly occur in amphibolitic and siliceous carbonate rocks; (iii) are found in host rocks belonging to widely separated stratigraphic units in the greenstone belt succession; (iv) display no obviously consistent genetic associations; (v) are typically weakly mineralised. Attention is drawn to the recently postulated theory that tungsten, and spatially related antimony and mercury, mineralisation in the Murchison Range owes its origin to syngenetic processes of concentration, the implications of which, may prove to be important to future investigations. All indications are, however, that the mineralisation is not characterised by any one particular mode of occurrence and that it may not be all of the same age and origin. All known scheelite deposits in the region under review have thus far proved to be of little economic importance

  1. Archaean greenstone belts and associated granitic rocks - A review (United States)

    Anhaeusser, Carl R.


    Archaean greenstone belts and associated granitic rocks comprise some of the most diverse rock types on the Earth's surface and were formed during the early stages of the development of the planet from Eoarchaean to Neoarchaean times - a period extending back from about 4000 to 2500 million years ago. Because of their great age, these rocks have received unprecedented attention from a wide spectrum of Earth scientists striving to learn more about the evolution of the Earth, including its crust, hydrosphere, atmosphere, the commencement of life, and the nature and distribution of mineral deposits. The knowledge gained thus far has accumulated incrementally, beginning with solid field-based studies, the latter being supplemented with increasingly advanced technological developments that have enabled scientists to probe fundamental questions of Earth history. Archaean granite-greenstone terranes display considerable variability of lithologies and geotectonic events, yet there are unifying characteristics that distinguish them from other geological environments. Most greenstone belts consist of a wide variety of volcanic and sedimentary rocks that reflect different evolutionary conditions of formation and all have invariably been influenced by subsequent geotectonic factors, including the intrusion of ultramafic, mafic and granitic complexes, resulting in widespread deformation, metamorphism, metasomatism, as well as mineralization. Geochemical and isotopic age determinations have shown how complex these ancient rocks are and efforts at understanding the nature and evolution of the hydrosphere, atmosphere and primitive life have made Archaean terranes exciting environments in which to study. Conflicting views as to the nature, history and origin of many of the rock types and events in Archaean terranes has been ongoing and stimulating. This review attempts to describe the main lithotypes and other characteristics of granite-greenstone belt geology and points to some

  2. The auriferous placer at Mount Robert, Pietersburg Greenstone belt

    International Nuclear Information System (INIS)

    The Mount Robert gold placer near Potgietersrus occurs in coarse, matrix-supported conglomerates of the Uitkyk Formation within the Pietersburg greenstone belt. Sedimentological and mineralogical investigations indicate that the conglomerates and the ore minerals were derived from a greenstone provenance, and that they were deposited in a braided river environment within a rapidly subsiding trough. Lack of sedimentological concentration of the heavy minerals is considered to be the main reason for the low and erratic gold grades encountered (usually below 1 g/t) and, thus, the failure of all past mining ventures. The mineralogical composition of the Mount Robert ore closely resembles that of the Witwatersrand deposits. However, uraninite is absent, probably as a result of its complete removal by weathering processes. Remaining small uranium concentrations can still be detected within the conglomerates where they occur associated with grains of carbonaceous matter, leucoxene aggregates, and secondary iron-hydroxides. U3O8 values found in the conglomerates are given

  3. Scheelite distribution a long of amphibolitic belt from greenstone belt Barbacena, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    In the middle southern portion of the Minas Gerais state a 60 Km long and 12 Km wide tungsten belt was discovered, and related to the amphibolitic rocks of the Barbacena Greenstone. Tungsten, present as scheelite, is associated with amphibolites, amphibole schists and amphibole gneisses, with chemical characteristics indicating an igneous origin. Chemical analyses on pan concentrates by I.C.P. showed high values on lead, tin, yttrium, lanthanum, cerium and zirconium, and average values for zinc and copper. The scheelite mineralization is probably strata bound and has a possible submarine exhalative origin. (author)

  4. Zircon Lu-Hf systematics: Evidence for the episodic development of Archaean greenstone belts (United States)

    Smith, P. E.; Tatsumoto, M.; Farquhar, R. M.


    A combined U-Th-Pb and Lu-Hf isotopic study of zircons was undertaken in order to determine the provenance and age of an Archean granite-greenstone terrain and to test the detailed application of the Lu-Hf system in various Archean zircons. The eastern Wawa subprovince of the Superior province consists of the low grade Michipicoten and Gamitagama greenstone belts and the granitic terrain. The Hf isotopic data indicate that the typical lithological features of a greenstone belt cycle could be accommodated in a crustal growth model that involved decreasing depth of melting in three isotopically distinct reservoirs: mantle, lower crust and upper crust. The model age of the sources given by the intersection of the lower crustal curve with the bulk earth evolution curve is about 2900 My, in good agreement with the zircon U-Pb basement age. This linear array also has a similar intersection age to that of Proterozoic carbonatite complexes. The general convergence of the other reservoir vectors around this age suggests that mantle depletion, crustal extraction and intracrustal differentiation were all part of the same episodic event. It is also apparent that recycling of older basement was important in the formation of many of the later greenstone belt rocks.

  5. The Murchison Greenstone Belt, South Africa: Accreted slivers with contrasting metamorphic conditions


    Block, Sylvain; Moyen, Jean-François; Zeh, Armin; Poujol, Marc; Jaguin, Justine; Paquette, Jean-Louis


    This paper presents new petrological and geochronological data for the ∼3.09-2.92 Ga Murchison Greenstone Belt (MGB), located in South Africa's Kaapvaal Craton, and discusses their geotectonic implications. The MGB is made of three tectono-metamorphic units: the Silwana Amphibolites, the Murchison Unit and the La France Formation. They underwent contrasting clockwise pressure-temperature-deformation (P-T-D) histories, and are separated from each other by relatively narrow, high-strain shear z...

  6. Petrology and geochemistry of metamorphosed komatiites and basalts from the Sula Mountains greenstone belt, Sierra Leone (United States)

    Rollinson, Hugh

    The Sula Mountains greenstone belt is the largest of the late-Archaean greenstone belts in the West African Craton. It comprises a thick (5km) lower volcanic formation and a thinner (2km) upper metasedimentary formation. Komatiites and basalts dominate the volcanic formation and komatiites form almost half of the succession. All the volcanic rocks are metamorphosed to amphibolite grade and have been significantly chemically altered. Two stages of alteration are recognised and are tentatively ascribed to hydrothermal alteration and later regional amphibolite facies metamorphism. Ratios of immobile trace elements and REE patterns preserve, for the most part, original igneous signatures and these are used to identify five magma types. These are: low-Ti komatiites - depleted in light REE; low-Ti komatiites - with flat REE patterns; high-Ti komatiitic basalts - with flat REE; low-Ti basalts - depleted in light REE; high-Ti basalts - with flat REE patterns. Much of the variation between the magma types can be explained in terms of different melt fractions of the mantle source, although there were two separate mantle sources one light REE depleted, the other not. The interleaving of the basalts and komatiites produced by this melting indicates that the two mantle sources were melted simultaneously. The simplest model with which to explain these complex melting processes is during melting within a rising mantle plume in which there were two different mantle compositions. The very high proportion of komatiites in the Sula Mountains relative to other greenstone belts suggests either extensive deep melting and/or the absence of a thick pre-existing crust which would have acted as a ``filter'' to komatiite eruption.

  7. The structural history and mineralization controls of the world-class Geita Hill gold deposit, Geita Greenstone Belt, Tanzania (United States)

    Sanislav, I. V.; Brayshaw, M.; Kolling, S. L.; Dirks, P. H. G. M.; Cook, Y. A.; Blenkinsop, T. G.


    The Geita Hill gold deposit is located in the Archean Geita Greenstone Belt and is one of the largest gold deposits in East Africa. The Geita Greenstone Belt experienced a complex deformation and intrusive history that is well illustrated and preserved in and around the Geita Hill gold deposit. Deformation involved early stages of ductile shearing and folding (D1 to D5), during which episodic emplacement of large diorite intrusive complexes, sills, and dykes occurred. These ductile deformation phases were followed by the development of brittle-ductile shear zones and faults (D6 to D8). The last stages of deformation were accompanied by voluminous felsic magmatism involving the intrusion of felsic porphyry dykes, within the greenstone belt, and the emplacement of large granitic bodies now forming the margins of the greenstone belt. Early, folded lamprophyre dykes, and later lamprophyre dykes, crosscutting the folded sequence are common, although volumetrically insignificant. The gold deposit formed late during the tectonic history of the greenstone belt, post-dating ductile deformation and synchronous with the development of brittle-ductile shear zones that overprinted earlier structural elements. The main mineralizing process involved sulfide replacement of magnetite-rich layers in ironstone and locally the replacement of ferromagnesian phases and magnetite in the diorite intrusions. The intersection between the brittle-ductile (D6) Geita Hill Shear Zone and different structural elements of ductile origin (e.g., fold hinges), and the contact between banded ironstone and folded diorite dykes and sills provided the optimal sites for gold mineralization.

  8. Micro-PIXE elemental imaging of pyrites from the Bulawayan-Bubi Greenstone Belt, Zimbabwe

    International Nuclear Information System (INIS)

    Micro-PIXE at the NAC nuclear microprobe was used for studies of a sequence of unusual pyrite-bearing carbonate sediments from the east of Turk Mine, Bubi Greenstone Belt, Zimbabwe. This pyrite mineralization shows a variety of textures, and its petrographic interpretation needed more solid geochemical evidence. Elemental maps were obtained using Dynamic Analysis (DA) (a rapid matrix transform method) which forms part of the GeoPIXE software package, and were complemented by point analyses in selected areas. The implemented on-demand beam deflection system allowed for count rates of the order of 3000 counts/s with negligible dead time. The distribution of As and other elements confirmed the petrographic interpretation of three different pyrite generations. In addition, point analyses showed that Sb and Pb were significantly elevated in the zones of As enrichment

  9. Geochemistry of the Neoarchaean Volcanic Rocks of the Kilimafedha Greenstone Belt, Northeastern Tanzania

    Directory of Open Access Journals (Sweden)

    Charles W. Messo


    Full Text Available The Neoarchaean volcanic rocks of the Kilimafedha greenstone belt consist of three petrological types that are closely associated in space and time: the predominant intermediate volcanic rocks with intermediate calc-alkaline to tholeiitic affinities, the volumetrically minor tholeiitic basalts, and rhyolites. The tholeiitic basalts are characterized by slightly depleted LREE to nearly flat REE patterns with no Eu anomalies but have negative anomalies of Nb. The intermediate volcanic rocks exhibit very coherent, fractionated REE patterns, slightly negative to absent Eu anomalies, depletion in Nb, Ta, and Ti in multielement spidergrams, and enrichment of HFSE relative to MORB. Compared to the other two suites, the rhyolites are characterized by low concentrations of TiO2 and overall low abundances of total REE, as well as large negative Ti, Sr, and Eu anomalies. The three suites have a εNd (2.7 Ga values in the range of −0.51 to +5.17. The geochemical features of the tholeiitic basalts are interpreted in terms of derivation from higher degrees of partial melting of a peridotite mantle wedge that has been variably metasomatized by aqueous fluids derived from dehydration of the subducting slab. The rocks showing intermediate affinities are interpreted to have been formed as differentiates of a primary magma formed later by lower degrees of partial melting of a garnet free mantle wedge that was strongly metasomatized by both fluid and melt derived from the subducting oceanic slab. The rhyolites are best interpreted as having been formed by shallow level fractional crystallization of the intermediate volcanic rocks involving plagioclase and Ti-rich phases like ilmenite and magnetite as well as REE-rich phases like apatite, zircon, monazite, and allanite. The close spatial association of the three petrological types in the Kilimafedha greenstone belt is interpreted as reflecting their formation in an evolving late Archaean island arc.

  10. Geotectonic evolution of granitoid-greenstone belts from Crixas, Guarinos, Pilar de Goias - Hidrolina (Goias), Brazil

    International Nuclear Information System (INIS)

    The area in discussion, in a geologic context, constitutes one of the most interesting and complex, within the South American Platform, in Brazilian territory, over which granitoid-greenstone belts are outstanding. The Goiano Complex is the oldest unit in the geologic column herein adopted and composed largely of granitoids, gneiss and migmatites, in the amphibolite facies. Dated samples of the complex have shown two isochrones of Rb/Sr reference, the oldest one is 2.926 +- 65 m.y. and the 87 Sr/86 Sr initial ratio of 0.7001 and the youngest on of 2.471 + 20 m.y. and 87 Sr/86 Sr initial ratio of 0.701. Although the initial ratios data of the Rb/Sr isochron, as well as the parameters in the Pb/Pb analyses may indicate material of mantle source, it may be interpreted, with the help of field data, that the youngest values may indicate the reworking of crustal sialic rocks formed 2.925 +- 65 m.y. ago (oldest isochron), with primitive material contribution. Before such reworking volcanic-sedimentary sequence was deposited over the already formed sialic crust, and it is denominated Pilar de Goias Supergroup which characterizes the Greenstone Belts in the region. The Archean age for the supergroup was evident through the age results of its ultramafic rocks, showing 2.600 m.y. isochron age, with Sm/Nd methods. Besides the geochronology and field studies, basic information for the construction of the geologic column herein presented, there has been done petrographic and litho geochemical studies, both in the Goiano Complex and Pilar de Goias Supergroup, as for the Pilar de Goias Supergroup, the studies were concentrated on its mafic-ultramafic rocks. (author)

  11. Single zircon ages for felsic to intermediate rocks from the Pietersburg and Giyani greenstone belts and bordering granitoid orthogneisses, northern Kaapvaal Craton, South Africa (United States)

    Kröner, A.; Jaeckel, P.; Brandl, G.


    Previous models for the temporal evolution of greenstone belts and surrounding granitoid gneisses in the northern Kaapvaal Craton can be revised on the basis of new single zircon ages, obtained by conventional UPb dating and PbPb evaporation. In the Pietersburg greenstone belt, zircons from a metaquartz porphyry of the Ysterberg Formation yielded an age of 2949.7±0.2 Ma, while a granite intruding the greenstones, and deformed together with them, has an age of 2853 + 19/-18 Ma. These data show felsic volcanism in this belt to have been coeval with felsic volcanism in the Murchison belt farther east, and the date of ˜2853 Ma provides an older age limit for deformation in the region. In contrast, a meta-andesite of the Giyani greenstone belt has a zircon age of 3203.3±0.2 Ma, while a younger and cross-cutting feldspar porphyry has an emplacement age of 2874.1±0.2 Ma. The meta-andesite is intercalated with various mafic and ultramafic rocks and, therefore, the age of 3.2 Ga appears plausible for the bulk of the Giyani greenstones. Granitoid gneisses surrounding the Pietersburg and Giyani belts vary in composition from tonalite to granite and texturally from well-layered to homogeneous but strongly foliated. These rocks yielded zircon ages between 2811 and 3283 Ma. The pre-3.2 Ga gneisses are polydeformed and may have constituted a basement to the Giyani greenstone sequence, while the younger gneisses are intrusive into the older gneiss assemblage and/or into the greenstones. The Giyani and Pietersburg belts probably define two separate crustal entities that were originally close together but were later displaced by strike-slip movement.

  12. Archaean hydrothermal zircon in the Abitibi greenstone belt: Constraints on the timing of gold mineralisation

    International Nuclear Information System (INIS)

    Hydrothermal zircons have been found in Archaean mesothermal Au-veins and altered wallrock selvages at Val d'Or, in the Abitibi greenstone belt of Canada. The zircons are paragenetically associated with vein quartz, tourmaline, mica, carbonate, scheelite, pyrite, and gold. Zirconium mobility, and the consequent occurrence of hydrothermal zircon, may be associated with the intense tourmalinisation characteristic of Archaean gold deposits in this district. The SHRIMP ion-microprobe has been used to analyse hydrothermal zircons from four separate mines spatially associated with the Bourlamaque batholith, and has yieleded ages constraining formation of the Au-bearing vein systems to within 20 Ma of emplacement of the pluton. The ion microprobe data reveal multiple stages of hydrothermal zircon growth in the vein systems, contemporaneous with the regional metamorphic peak and late kinematic activity along regional structures. Younger (including Proterozoic) ages previously obtained for the veins, using other minerals and isotopic schemes, must reflect either alteration or renewed mineral growth during much later reactivation of fluids along the same structures up to 400 Ma after initial formation of the veins. (orig.)

  13. Drilling for the Archean Roots of Life and Tectonic Earth in the Barberton Mountains

    Directory of Open Access Journals (Sweden)

    Nicola McLoughlin


    Full Text Available In the Barberton Scientific Drilling Program (BSDP we successfully completed three drill holes in 2008 across strategically selected rock formations in the early Archean Barberton Greenstone Belt, South Africa. This collaborative project’s goal is to advance understanding of geodynamic and biogeochemical processes of the young Earth. The program aims to better define and characterize Earth’s earliest preserved ocean crust shear zones and microbial borings in Archean basaltic glass, and to identify biogeochemical fingerprints of ancient ecological niches recorded in rocks. The state-of-the-art analytical and imaging work will address the question of earliest plate tectonics in the Archean, the δ18O composition, the redox state and temperature of Archean seawater, and the origin of life question.

  14. Isotopic geochronological evidence for the Paleoproterozoic age of gold mineralization in Archean greenstone belts of Karelia, the Baltic Shield (United States)

    Larionova, Yu. O.; Samsonov, A. V.; Shatagin, K. N.; Nosova, A. A.


    The Rb-Sr age of metasomatic rocks from four gold deposits and occurrences localized in Archean granite-greenstone belts of the western, central, and southern Karelian Craton of the Baltic Shield has been determined. At the Pedrolampi deposit in central Karelia, the dated Au-bearing beresite and quartz-carbonate veins are located in the shear zone and replace Mesoarchean (˜2.9 Ga) mafic and felsic metavolcanic rocks of the Koikar-Kobozero greenstone belt. At the Taloveis ore occurrence in the Kostomuksha greenstone belt of western Karelia, the dated beresite replaces Neoarchean (˜2.7 Ga) granitoids and is conjugated with quartz veins in the shear zone. At the Faddeinkelja occurrence of southern Karelia, Aubearing beresite in the large tectonic zone, which transects Archean granite and Paleoproterozoic mafic dikes, has been studied. At the Hatunoja occurrence in the Jalonvaara greenstone belt of southwestern Karelia, the studied quartz veins and related gold mineralization are localized in Archean granitoids. The Rb-Sr isochrons based on whole-rock samples and minerals from ore-bearing and metasomatic wall rocks and veins yielded ˜1.7 Ga for all studied objects. This age is interpreted as the time of development of ore-bearing tectonic zones and ore-forming hydrothermal metasomatic alteration. New isotopic data in combination with the results obtained by our precursors allow us to recognize the Paleoproterozoic stage of gold mineralization in the Karelian Craton. This stage was unrelated to the Archean crust formation in the Karelian Block and is a repercussion of the Paleoproterozoic (2.0-1.7 Ga) crust-forming tectonic cycle, which gave rise to the formation of the Svecofennian and Lapland-Kola foldbelts in the framework of the Karelain Craton. The oreforming capability of Paleoproterozoic tectonics in the Archean complexes of the Karelian Craton was probably not great, and its main role consisted in reworking of the Archean gold mineralization of various

  15. Evidence for spreading in the lower Kam Group of the Yellowknife greenstone belt: Implications for Archaean basin evolution in the Slave Province (United States)

    Helmstaedt, H.; Padgham, W. A.

    The Yellowknife greenstone belt is the western margin of an Archean turbidite-filled basin bordered on the east by the Cameron River and Beaulieu River volcanic belts (Henderson, 1981; Lambert, 1982). This model implies that rifting was entirely ensialic and did not proceed beyond the graben stage. Volcanism is assumed to have been restricted to the boundary faults, and the basin was floored by a downfaulted granitic basement. On the other hand, the enormous thickness of submarine volcanic rocks and the presence of a spreading complex at the base of the Kam Group suggest that volcanic rocks were much more widespread than indicated by their present distribution. Rather than resembling volcanic sequences in intracratonic graben structures, the Kam Group and its tectonic setting within the Yellowknife greenstone belt have greater affinities to the Rocas Verdes of southern Chile, Mesozoic ophiolites, that were formed in an arc-related marginal basin setting. The similarities of these ophiolites with some Archean volcanic sequences was previously recognized, and served as basis for their marginal-basin model of greenstone belts. The discovery of a multiple and sheeted dike complex in the Kam Group confirms that features typical of Phanerozoic ophiolites are indeed preserved in some greenstone belts and provides further field evidence in support of such a model.

  16. Petrographic and mineragraphic investigations of the archaean gold placer at Mount Robert in the Pietersburg greenstone belt, Northern Transvaal

    International Nuclear Information System (INIS)

    The fossil gold placer on Mount Robert near Potgietersrus, northern Transvaal, occurs in the Uitkyk Formation. This formation consists of arenaceous rocks with interlayered conglomerates and shales, and occurs at the top of the Archaean Pietersburg Sequence which forms the Pietersburg greenstone belt. The host rock of the occurrence consists of conglomerates. Its fragments indicate that the provenance area consisted of acid porphyritic lava, chert, banded iron-formation, quartzite, basic lava, vein quartz, and shale. It is suggested that the Uitkyk sediments were transported over short distances and originated from the erosion of a greenstone terrane. The mineralogy of the ore is relatively simply and resembles that of the much younger Witwatersrand banket. Rounded allogenic and, to a lesser extent, idiomorphic to hypidiomorphic authigenic pyrite form the main constituents. Less abundant but genetically interesting ore minerals that have been found so far are leucoxene-rutile, chromite, molybdenite, zircon, carbonaceous matter, and brannerite. The Mount Robert occurrence can be regarded as a primitive forerunner of the Witwatersrand goldfield. Ineffective sedimentary enrichment processes and an environment unfavourable for life-forms that could have acted as biogenic gold and uranium concentrators are regarded as possible reasons for the low gold content and scarcity of uranium-bearing minerals in the investigated Uitkyk conglomerates

  17. Diamonds in an Archean greenstone belt: Diamond suites in unconventional rocks of Wawa, Northern Ontario (Canada) (United States)

    Kopylova, Maya; Bruce, Loryn; Ryder, John


    Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites. In contrast, Wawa diamonds are hosted in "unconventional", non-kimberlitic rocks that formed contemporaneously with the mafic and sedimentary rocks of the Archean Michipicoten Greenstone Belt (MGB). We studied two diamond suites that occur within the 2.9-2.7 Ga greenschist facies rocks of MGB located in the southwest portion of the Superior Craton (E. Canada). The first diamond suite henceforth referred to as the Wawa breccia diamonds (384 stones), are hosted in the 2618-2744 Ma calc-alkaline lamprophyres and volcaniclastic breccias, contemporaneous with pillow basalts and felsic volcanics of MGB. The second suite, the Wawa conglomerate diamonds (80 crystals), are hosted in the 2697-2700 Ma poorly sorted sedimentary polymictic conglomerate which is interpreted as a proximal alluvial fan debris flow in a fan-delta environment. The majority of the diamonds was found within the matrix of the conglomerate. The diamondiferous breccia occurs 20 km north of the town of Wawa, whereas the conglomerate is found 12 km northeast of Wawa. Diamonds from the 2 occurrences were characterized and described for provenance studies. Both the breccia and conglomerate diamonds show similar crystal habits, with the predominance of octahedral single crystals and ~ 10% of cubes. The conglomerate diamonds are significantly less resorbed (no resorbtion in 43% of the stones) than the breccia diamonds (8% non-resorbed stones). In both suites, only 21-24% show high degrees of resorption. The majority of crystals in both suites are colourless, with some yellow, brown and grey stones. Conglomerate diamonds had a wider variety of colours that were not seen in the breccia diamonds, including green and pink. The breccia diamonds contain 0-740 ppm N and show two modes of N aggregation at 0-30 and 60-95%. Among the breccia diamonds, Type IaA stones comprise 17%, whereas IaAB stones make up 49% of the

  18. Geochemistry and petrogenesis of intrusions at the Golden Pride gold deposit in the Nzega greenstone belt, Tanzania (United States)

    Kwelwa, Shimba; Manya, Shukrani; Vos, Ivo M. A.


    The greenstone sequence at Golden Pride gold deposit in Nzega greenstone belt of northern Tanzania is cross-cut by several intrusions whose geochemistry and petrogenesis is unknown. We present major and trace elements geochemistry of the Golden Pride igneous intrusions with the aim of constraining their petrogenesis and their ancient tectonic setting. The Golden Pride intrusions are geochemically categorized into two main rock suites: the granodiorites (which include the porphyries) and the lamprophyres (formerly intermediate intrusions). The granodiorites are characterized by SiO2 contents of 54.5-69.9 wt%, elevated MgO (1.22-3.59 wt%) Cr (up to 54 ppm), Mg# (35-55) pointing to a mantle component in the source. Compared to the TTG and adakites, the granodiorites are characterized by higher K2O (1.52-4.30 wt%), medium HREE (Gd/ErCN = 2.13-3.77) and marked enrichment in Ba and Sr (Ba + Sr = 819-2922 ppm) and are in these respects similar to Archean high Ba-Sr sanukitoids. The rocks in this suite are interpreted to have formed by partial melting of an enriched mantle wedge through two metasomatic events: subduction-related fluids/melts and by metasomatism related to asthenospheric mantle upwelling caused by slab break-off. Compared to the granodiorites, the lamprophyres have higher MgO contents (2.37-3.81 wt%), Cr (60-298 ppm), Co (31-57 ppm) and Mg# (32-40). They also show slight enrichment of the LREE relative to HREE (La/YbCN = 3.3-7.1), moderate Nb-Ti depletion and sub-chondritic Zr/Hf ratios (34-41). These geochemical features are attributed to derivation of the Golden Pride lamprophyres by partial melting of the amphibole-rich metasomatized mantle by slab derived hydrous fluids. Both of the Golden Pride intrusion suites show strong affinity to subduction related magmas and we interpret that the entire greenstone sequence and the associated intrusions at Golden Pride gold deposit formed in a late Archaean convergent margin.

  19. The discovery of the Neoarchean mafic dyke swarm in Hengshan and reinterpretation of the previous "Wutai greenstone belt"

    Institute of Scientific and Technical Information of China (English)


    The structural mapping and section study indicate that the "greenstone belts" in the southern to central parts of Hengshan were intensively sheared and transposed mafic dyke swarm,which originally intruded into the Neoarchean grey gneiss and high-pressure granulite terrain(HPGT).The HPGT is characterized by flat-dipping structures,to the south it became steep and was cut by the Dianmen mafic dyke swarm.After high-pressure granulite-facies metamorphic event,the mafic dyke swarm occurred,and was associated with the extensional setting and reworked by the late strike-slip shearing.The zircon age dating proves that the Dianmen mafic dyke swarm was emplaced during the period between 2499±4 Ma and 2512±3 Ma,followed by late tectonothermal reworking.The Dianmen mafic dyke swarm further documents the extensional episode in the central to northern parts of North China Craton(NCC),providing the important constraint for the limit between Archean and Proterozoic and correlation between NCC and other cratonic blocks of the world.

  20. Geochemistry of metavolcanic rocks in the Archean Greenstone Belt of Identidade, SE Para, Brazil

    International Nuclear Information System (INIS)

    The paper discusses the geochemistry of the ultramafic and mafic volcanic rocks of the Identidade belt (IDB), in order to present hypothesis about their possible sources and magmatic evolution. The chemical data were obtained by ICP method. The analytical errors are less then 5% for major elements, less than 10% for the minor ones, and around 5% for trace elements. Save additional data from the meta ultramafic rocks of the Seringa belt, situated 100 km to the west of the IDB, were also considered. The XLFRAC program was employed for fractional crystallization modelling of major elements. For trace element modelling the equations of fractional crystallization and equilibrium partial melting were applied, using an unpublished program written in Pascal. 10 figs. 8 tabs

  1. Age constraints on felsic intrusions, metamorphism and gold mineralisation in the Palaeoproterozoic Rio Itapicuru greenstone belt, NE Bahia State, Brazil (United States)

    Mello, E.F.; Xavier, R.P.; McNaughton, N.J.; Hagemann, S.G.; Fletcher, I.; Snee, L.


    U-Pb sensitive high resolution ion microprobe mass spectrometer (SHRIMP) ages of zircon, monazite and xenotime crystals from felsic intrusive rocks from the Rio Itapicuru greenstone belt show two development stages between 2,152 and 2,130 Ma, and between 2,130 and 2,080 Ma. The older intrusions yielded ages of 2,152??6 Ma in monazite crystals and 2,155??9 Ma in zircon crystals derived from the Trilhado granodiorite, and ages of 2,130??7 Ma and 2,128??8 Ma in zircon crystals derived from the Teofila??ndia tonalite. The emplacement age of the syntectonic Ambro??sio dome as indicated by a 2,080??2-Ma xenotime age for a granite dyke probably marks the end of the felsic magmatism. This age shows good agreement with the Ar-Ar plateau age of 2,080??5 Ma obtained in hornblendes from an amphibolite and with a U-Pb SHRIMP age of 2,076??10 Ma in detrital zircon crystals from a quartzite, interpreted as the age of the peak of the metamorphism. The predominance of inherited zircons in the syntectonic Ambro??sio dome suggests that the basement of the supracrustal rocks was composed of Archaean continental crust with components of 2,937??16, 3,111??13 and 3,162??13 Ma. Ar-Ar plateau ages of 2,050??4 Ma and 2,054??2 Ma on hydrothermal muscovite samples from the Fazenda Brasileiro gold deposit are interpreted as minimum ages for gold mineralisation and close to the true age of gold deposition. The Ar-Ar data indicate that the mineralisation must have occurred less than 30 million years after the peak of the metamorphism, or episodically between 2,080 Ma and 2,050 Ma, during uplift and exhumation of the orogen. ?? Springer-Verlag 2006.

  2. Structural and geochemical mapping of a Fe-mineralized quartz-mica rich unit in the Ringvassøya Greenstone Belt, West Troms Basement Complex


    Elvenes, Hallgeir


    Ringvassøy is one of a chain of large coastal islands representing the Archaean to Paleoproterozoic West Troms Basement Complex (WTBC), west of the Caledonides. On Ringvassøy, a basement of mainly tonalitic gneiss is overlain by the Ringvassøy Greenstone Belt (RGB), which is metamorphosed up to middle amphibolite facies. Tonalitic gneiss in the west and southeast of the island has U–Pb zircon ages of 2.84–2.82 Ga, similar to U–Pb zircon ages of 2.85–2.83 Ga for metavolcanics in the RGB. Mafic...

  3. Field and geochemical characterisitics of the Mesoarchean (~3075 ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in a supra-subduction oceanic crust

    DEFF Research Database (Denmark)

    Polat, A.; Appel, P.W.U.; Frei, Robert;


    The Mesoarchean (ca. 3075 Ma) Ivisaartoq greenstone belt in southern West Greenland includes variably deformed and metamorphosed pillow basalts, ultramafic flows (picrites), serpentinized ultramafic rocks, gabbros, sulphide-rich siliceous layers, and minor siliciclastic sedimentary rocks. Primary......-enriched, near-flat HREE, and HFSE (especially Nb)-depleted trace element patterns, indicating a subduction zone geochemical signature. Ultramafic pillows and cumulates display large positive initial eNd values of + 1.3 to + 5.0, consistent with a strongly depleted mantle source. Given the geological...

  4. Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil (United States)

    Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca


    Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt

  5. U-Pb SHRIMP ages of detrital zircons from Hiriyur formation in Chitradurga Greenstone belt and its implication to the Neoarchean evolution of Dharwar craton, South India

    International Nuclear Information System (INIS)

    We report newly obtained U-Pb SHRIMP ages of detrital zircons from metagreywackes in the Hiriyur Formation (Chitradurga Group, Dharwar Supergroup) from the central eastern part of the Chitradurga greenstone belt. U-Pb analyses yield three major Neoarchean age populations ranging from 2.70 - 2.54 Ga with some minor age population of Mesoarchean. The maximum age of deposition is constrained by the youngest detrital zircon population at 2546 Ma. This is the first report of the occurrence of supracrustal rocks less than 2.58 Ga in the central part of Chitradurga greenstone belt. Close evaluation of detrital ages with the published ages of surrounding igneous rocks suggest that the youngest detrital zircons might be derived from rocks of the Eastern Dharwar craton and the inferred docking of the western and eastern Dharwar cratons happened prior to the deposition of the Hiriyur Formation. The Chitradurga shear zone, dividing the Dharwar craton into western and eastern blocks, probably developed after the deposition. Furthermore, the lower intercept is interpreted as evidence for the Pan-African overprints in the study area. (author)

  6. The origin of late archaean granitoids in the Sukuma land greenstone belt of northern Tanzania: Geochemical and isotopic constraints

    International Nuclear Information System (INIS)

    Granitoids intruding the late Archaean sequences of the Sukumaland Greenstone Belt of northern Tanzania belong to two distinct geochemical suites. Suite 1 is characterised by Na2O/K2O > 1 (1.04 - 4.67), high Sr/Y (56 - 204) and Ba/Rb ratios (6.1 - 27.1) and low Rb/Sr ratios (0.08 - 0.25). The rocks are enriched in Sr (405 - 1264 ppm) and depleted in Yb (0.17 - 0.93 ppm) and Rb (56 -132 ppm). On chondrite-normalised REE diagrams, the rocks display highly fractionated patterns characterised by relative LREE enrichment ((La/Yb)N = 23 - 128 and (Gd/Yb)N = 3.10- 8.54) and lower concentrations of the HREE (YbN = 0.80 - 4.45). On primitive mantle-normalised spidergrams, Nb and Ti, together with P and Y are depleted relative to adjacent elements. The major and trace element characteristics of Suite 1 are comparable to those of typical Archaean TTG suites and High Silica Adakites (HSA). Suite 2 granitoids are characterised by Na2O/K2O N = 15 -86 and (Gd/Yb)N = 1.73 - 6.74) and are characterised by higher concentrations of the HREE (YbN = 2.1 - 6.5). On primitive mantle-normalised spidergrams, Suite 2 samples, like those of Suite 1, show relative depletion in Th, Nb and Ti, together with P and Y relative to adjacent elements. Sm-Nd mean crustal residence ages for both suites are indistinguishable and range between 2470 and 2720 Ma with a mean of 2610 ± 35 Ma (2 SE), similar to the emplacement age of 2620 ± 40 Ma. The granitoids are interpreted to have formed by partial melting at the base of a late Archaean thickened sub-arc basaltic crust. Melting to form the Suite 1 granitoids occurred in the eclogite stability field whereas Suite 2 formed by melting at shallower depth in the garnet amphibolite stability field. (author)

  7. Geochemistry of the metavolcanic rocks in the vicinity of the MacLellan Au-Ag deposit and an evaluation of the tectonic setting of the Lynn Lake greenstone belt, Canada: Evidence for a Paleoproterozoic-aged rifted continental margin (United States)

    Glendenning, Michael W. P.; Gagnon, Joel E.; Polat, Ali


    The Paleoproterozoic (ca. 1900 Ma) Lynn Lake greenstone belt of northern Manitoba, Canada, has been previously characterized as comprising a series of tectonically juxtaposed intra-oceanic-derived metavolcanic rocks. The results of more recent local and regional studies, however, support a significant contribution of continental crust during formation of the metasedimentary, metavolcanic, and intrusive igneous rocks that comprise the majority of the Lynn Lake greenstone belt. The tectonic model previously proposed for the Lynn Lake greenstone belt, however, did not consider the geodynamics of the Lynn Lake greenstone belt in the context of all available data. In this study, we report the results of outcrop mapping and petrographic analysis, as well as major, minor, and trace element geochemical analyses for 54 samples from the Northern terrane, and integrate and compare the results with data from previously published studies. These data are used to recharacterize the metavolcanic rocks and to develop a new geodynamic model for the formation of the Lynn Lake greenstone belt. Ultramafic to intermediate rocks in the vicinity of the MacLellan Au-Ag deposit are characterized primarily by E-MORB-like trace element characteristics and Th-Nb-La systematics, which are interpreted to be the result of a primary, plume-derived melt interacting with continental lithosphere at a thinned (i.e., rifted) continental margin. Similarly, the majority of the mafic to intermediate rocks that comprise the Lynn Lake greenstone belt are characterized by flat to E-MORB-like trace element patterns and Th-Nb-La systematics, which are consistent with mantle plume-derived, contaminated, oceanic continental rift or rifted margin setting rocks. This study suggests that the metavolcanic rocks of the Lynn Lake greenstone belt were derived via rifting between the Superior and Hearne Cratons, which resulted in the formation and growth of the Manikewan Ocean. Alternatively, the metavolcanic rocks

  8. Deep Metamorphic Rock Series of Bayan Wula-mountain Granite-greenstone Belt and Gold MineralizationMA Runze%巴彦乌拉山深变质岩系的花岗-绿岩带与金成矿

    Institute of Scientific and Technical Information of China (English)

    胡晰; 马润则; 陈志耕; 张腊梅; 陈娟; 刘颖倩


    A large area of Archean granite - greenstone belt exposed in Bayan wula-mountain, which bedrock outcrops good. Survey area′greenstone belt is existing as the green schist facies of tectonic schist. At present, domestic and foreign atta-ches great importance to the study of granite greenstone belt, The major reason is that research on it has mineral and geological sig-nificance. However, Gold directly affecting the financial securi-ty of the country as a precious metal, which is very important for the national economy stability. Granite - greenstone belt has a close relation with gold deposit. At present, China 's most im-portant gold producing type is greenstone type gold deposit.%巴彦乌拉山出露大面积的太古代花岗-绿岩带,基岩出露良好。本区的绿岩带是以变质程度为绿片相的构造片岩形式出现的。国内外对花岗绿岩带的研究非常重视,主要是因为其研究对矿产和地质都具有重大意义。然而金为直接影响国家金融安全的贵重金属,对于国家的经济稳定有极其重要的作用。其中花岗-绿岩带与金成矿有着密切关系。目前我国主要的产金类型为绿岩型金矿。

  9. Palaeomagnetism of Archaean rocks of the Onverwacht Group, Barberton Greenstone Belt (southern Africa): Evidence for a stable and potentially reversing geomagnetic field at ca. 3.5 Ga

    NARCIS (Netherlands)

    Biggin, A.J.; Wit, M.J. de; Langereis, C.G.; Zegers, T.E.; Voute, S.; Dekkers, M.J.; Drost, K.


    Palaeomagnetic data from the Palaeoarchaean Era (3.2–3.6 Ga) have the potential to provide us with a great deal of information about early conditions within, and processes affecting, the Earth's core, mantle, and surface environment. Here we present new data obtained from some of the oldest palaeoma

  10. Archean cherts from the Barberton Greenstone Belt (3.5-3.2Ga), South africa. Formation process and usability as paleo-environmental proxies


    Ledevin, Morgane,


    Archean cherts potentially constrain the primitive environment in which life emerged and evolved. These siliceous rocks formed by three processes : C-cherts (primary cherts) formed by the chemical precipitation of oceanic silica, either as a siliceous ooze (or silica gel) on the seabed, or as cement within still soft sediments at the surface ; F-cherts (fracturefilling cherts) precipitated from circulating fluids in concordant or crosscutting veins in the shallow crust ; S-cherts (secondary c...

  11. First data on Sm-Nd isotope systematics of the Kholodnikansk greenstone belt metavolcanites, the Southern Aldan shield

    International Nuclear Information System (INIS)

    The age of the Kholodnikansk greenstone metavolcanites, located in the south of the Southern Aldan shield, is determined through the method of the Sm-Nd dating with the purpose of studying its earth crust constituent segments formation. The obtained metavolcanites isochronous age, equal to 2.41±0.08 billion years testifies to the fact, that the processes of the early proterozoic activation (2.2-2.4 billion years ago) were manifested not only within the limits of the Central-Aldan complex but also in the south of the Aldan shield

  12. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail:; Armstrong, Richard [Australian National Univ., Canberra, ACT (Australia). Research School of Earth Sciences; Resende, Marcelo Goncalves [Universidade Catolica de Brasilia, DF (Brazil). Curso de Graduacao em Engenharia Ambiental


    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 {+-} 12 Ma) magmatic event. Sm-Nd isotopic data (initial e{sub CHUR} values between -10.5 and -14.9) and T{sub DM} values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  13. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

    International Nuclear Information System (INIS)

    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 ± 12 Ma) magmatic event. Sm-Nd isotopic data (initial eCHUR values between -10.5 and -14.9) and TDM values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  14. Paleoproterozoic Greenstone-Granite Belts in Northern Brazil and the Former Guyana Shield - West African Craton Province

    Directory of Open Access Journals (Sweden)

    Ian McReath


    Full Text Available The mainly meta-volcano-sedimentary Vila Nova Group and associated granites constitute separate belts, which formpart of a large paleoproterozoic (mainly rhyacian province in the Guyana Shield of which northern Brazil forms a part, andthe West African Craton. In Brazil the southwestern Serra do Ipitinga and Serra Tumucumaque-Serra do Navio belts have noobvious geometrical extensions in the Guyanas or Venezuela, and may represent deposits formed at penecontemporaneouspassive continental margins and ocean floor spreading centres. To the Northeast the Serra Lombarda-Tartarugalzinho andOiapoque belts are continuations of Guianese belts. In the former the igneous rocks have geochemical characteristics ofsuprasubduction environments. Belts in the Guyana Shield and West African Craton have many similar features. Themegaprovince evolved in a number of stages, which may have started at about 2.3 Ga, and continued with diminished activityafter 2.11 Ga. Both major juvenile additions and (possibly minor reworking of earlier crust contributed to the growth of theprovince. The major transcurrent deformation, responsible for the present structure of the belts, probably occurred duringthe later stages of evolution of the province, but metamorphism and deformation are registered even in the oldest rocks.

  15. Rochas ultramáficas plutônicas do greenstone belt Rio das Velhas na porção central do Quadrilátero Ferrífero, Minas Gerais, Brasil Plutonic ultramafic rocks of the greenstone belt Rio das Velhas in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, Brazil


    Gabriela Magalhães da Fonseca; Hanna Jordt Evangelista


    Em Amarantina, distrito de Ouro Preto, encontram-se rochas ultramáficas expostas em duas áreas com cerca de 500 m² cada. As rochas afloram no Complexo do Bação, que é o embasamento gnáissico do greenstone belt Rio das Velhas, na porção central do Quadrilátero Ferrífero (QF). O interesse no estudo petrogenético desses corpos deve-se à preservação parcial de minerais ígneos, ausentes na maior parte das rochas ultramáficas totalmente metamorfizadas do QF. Entre essas rochas, destacam-se os estea...

  16. Rochas ultramáficas plutônicas do greenstone belt Rio das Velhas na porção central do Quadrilátero Ferrífero, Minas Gerais, Brasil Plutonic ultramafic rocks of the greenstone belt Rio das Velhas in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriela Magalhães da Fonseca


    Full Text Available Em Amarantina, distrito de Ouro Preto, encontram-se rochas ultramáficas expostas em duas áreas com cerca de 500 m² cada. As rochas afloram no Complexo do Bação, que é o embasamento gnáissico do greenstone belt Rio das Velhas, na porção central do Quadrilátero Ferrífero (QF. O interesse no estudo petrogenético desses corpos deve-se à preservação parcial de minerais ígneos, ausentes na maior parte das rochas ultramáficas totalmente metamorfizadas do QF. Entre essas rochas, destacam-se os esteatitos e os serpentinitos, devido a sua importância econômica. As rochas ultramáficas de Amarantina possuem textura equigranular, fato que as caracteriza como tendo origem plutônica, isto é, trata-se de metaperidotitos. Possuem grãos maiores de olivina, piroxênio e espinélio da rocha ígnea original distribuídos em matriz metamórfica fina com talco, serpentinas, cloritas, anfibólios e minerais opacos. Escassas arita (NiSbAs e breithauptita (NiSb foram formadas a partir de pentlandita durante o metamorfismo associado a hidrotermalismo. A comparação da composição química com a de um metakomatiito com textura spinifex do QF, bem como com rochas komatitiiticas de outras partes do mundo, mostra que os metaperidotitos são, quimicamente, semelhantes aos komatiitos não-desfalcados em alumínio. Portanto é provável que as rochas ultramáficas estudadas correspondam à porção plutônica do magmatismo komatitiitico do Grupo Nova Lima, que é a unidade basal do greenstone belt Rio das Velhas.In Amarantina, district of Ouro Preto (State of Minas Gerais, Brazil, ultramafic rock exposures are found along two areas of about 500 m² each. The rocks crop out in the Bação complex, which is the gneissic basement of the Rio das Velhas greenstone belt in the central portion of the Quadrilátero Ferrífero (QF. The interest in a petrogenetic study of the ultramafic rocks is the partial preservation of igneous minerals, which are not observed

  17. The provenance and Sm/Nd Model ages of siliciclastic supracrustal rocks of the Faina and Santa Rita Greenstone belts, Goias, Brazil

    International Nuclear Information System (INIS)

    The Faina and Santa Rita greenstone belts are two N 60 deg C W trending synclinoria separated by a N 30 deg C E strike-slip fault and rest allochtonous on the adjacent Uva and Caicara granite-gneiss complexes. The belts are made up of lower metakomatiites, followed by metabasalts and thick metasedimentary sequences deposited under contrasting paleogeographic settings. In Faina, the sequence consists of two complete shelf cycles, the first resting on basalts by an erosional unconformity. In Santa Rita, the basalts give gradually place to carbonaceous metashales, unconformably overlain by metarhythmites. Provenance based on trace element geochemistry, mineral chemistry of chloride and muscovite, source-are modeling and REE elements indicate that protoliths of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita formed under the influence of a source area dominated by mafic ultramafic rocks, whilst during the sedimentation of the second shelf cycle and the metarhythmites of Santa Rita the source-area was dominated by TTG granitoids. Sm-Nd model ages of the lower sedimentary packages vary between 3.0 and 2.8 Ga and the upper between 2.7 and 2.6 Ga. These intervals coincide, respectively, with the estimated age of the underlying, and with the Sm-Nd, Rb-Sr e U-Pb ages of the main granitoids and gneisses of the adjacent complexes. The same data indicate that, during the sedimentation of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita, both basins had independent source-areas, but shared the same source during the upper sections. Weathering nature and intensity of the source-area calculated by means of geochemical a data suggest that the dramatic change of provenance from the lower to the upper sections is due to the shift from tectonically stable to unstable regimes, interpreted as resulting from the emergence of the island arc whose roots are represented by the adjacent granite-gneiss complexes. (author)

  18. Geological, geochemical and isotopic characteristics of the Archaean Kaap Valley pluton, Barberton mountain land, South Africa

    International Nuclear Information System (INIS)

    The Kaap Valley pluton consists predominantly of a homogeneous weakly foliated, hornblende-bearing tonalite. It is among the oldest granitoid bodies yet recognized in the environs of the Barberton greenstone belt, yielding 207Pb/206Pb mineral ages of about 3300 Ma and a Rb-Sr whole rock isochron age of about 3500 Ma. The Kaap Valley pluton is distinctive in many respects. Whereas all other gneiss plutons in the area are characterized by a trondhjemitic bulk composition with mafic mineralogies dominated by biotite, the Kaap Valley pluton is tonalitic in bulk composition with hornblende (plus minus minor biotite) as its major mafic phase. In this paper, the results of a detailed geological, geochemical and Pb-isotopic study of the Kaap Valley pluton are presented. Questions relating to the origin of the body are considered, with an emphasis on the formation of a tonalitic magma which is more mafic than those typically encountered in the region. Although exposure does not permit a detailed structural study of the gneiss pluton consideration is given to its mode of emplacement

  19. Ensialic tectonic setting of the archaean Rio das Velhas greenstone belt: Nd and Pb isotopic evidence from the Bonfim metamorphic complex, Quadrilatero Ferrifero, Brazil

    International Nuclear Information System (INIS)

    The Bonfim Metamorphic Complex is one of the sialic fragments that make up the Archaen crust of the Southern Sao Francisco Craton, eastern Brazil. The northern part of the Bonfim Metamorphic Complex, located in the Quadrilatero Ferrifero region, was investigated on the basis of petrology, geochemistry and U-Pb and Sm-Nd geochronology. This complex comprises eight lithostratigraphic units, six of them Neo Archaen in age, composed of trondhjemitic to granitic gneisses, intrusive granitoids and and amphibolites. The other two units are Mesoproterozoic and probably Phanerozoic mafic dikes. The origin of rock protoliths of the Bonfim Metamorphic Complex goes back to the 3200 Ma ago, as suggested by inherited U-Pb age components and Sm-Nd (TDM) crus formation ages. The main evolution of the Northern Bonfim Metamorphic Complex was associated with the Rio das Velhas Tectonothermal Event (2780 - 2700 Ma) that correlates with major Neo Archean events in the Southern Sao Francisco Craton. The Rio das Velhas event, in the Northern Bonfim Metamorphic Complex, is characteriszed by widespread metamorphism, calc-alkaline (tonalite bodies) and tholeitic magmatism within both the sialic crust and Rio das Velhas greenstone belt. The geological features together with geochemical signatures suggest a convergent margin setting for the Neoproterozoic evolution, which final steps are represented by an intrusive granite activity dated by U-Pb zircon at 2703± 24/20 Ma. During the proterozoic, the Neo-Archaen crust was affected by thermotectonic overprints, under low-grade facies metamorphic conditions, as suggested by resetting of the Rb-Sr (whole rock), and K-Ar (mineral) isotopic systems. Finally, from the petrological, geochemical and geochronological data, this paper presents a global tectonic model for the geological evolution from the Meso-to Neo Archaen in the Quadrilatero Ferrifero region. This model comprises the following geological setting and processes: active margins, mantelic

  20. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada (United States)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.


    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  1. Multiple sulfur and carbon isotope composition of sediments from the Belingwe Greenstone Belt (Zimbabwe): A biogenic methane regulation on mass independent fractionation of sulfur during the Neoarchean? (United States)

    Thomazo, Christophe; Nisbet, Euan G.; Grassineau, Nathalie V.; Peters, Marc; Strauss, Harald


    To explore the linkage between mass-independent sulfur isotope fractionation (MIF-S) and δ13Corg excursions during the Neoarchean, as well as the contemporary redox state and biogeochemical cycling of carbon and sulfur, we report the results of a detailed carbon and multiple sulfur (δ34S, δ33S, δ36S) isotopic study of the ∼2.7 Ga Manjeri and ∼2.65 Ga Cheshire formations of the Ngezi Group (Belingwe Greenstone Belt, Zimbabwe). Multiple sulfur isotope data show non-zero Δ33S and Δ36S values for sediments older than 2.4 Ga (i.e. prior to the Great Oxidation Event, GOE), indicating MIF-S thought to be associated with low atmospheric oxygen concentration. However, in several 2.7-2.5 Ga Neoarchean localities, small-scale variations in MIF-S signal (magnitude) seem to correlate with negative excursion in δ13Corg, possibly reflecting a global connection between the relative reaction rate of different MIF-S source reaction and sulfur exit channels and the biogenic flux of methane into the atmosphere during periods of localized, microbiologically mediated, shallow surface-water oxygenation. The Manjeri Formation black shales studied here display a wide range of δ13Corg between -35.4‰ and -16.2‰ (average of -30.3 ± 6.0‰, 1σ), while the Cheshire Formation shales have δ13Corg between -47.7‰ and -35.1‰ (average -41.3 ± 3‰, 1σ). The δ34S values of sedimentary sulfides from Manjeri Formation vary between -15.15‰ and +2.37‰ (average -1.71 ± 4.76‰, 1σ), showing very small and mostly negative Δ33S values varying from -0.58‰ to 0.87‰ (average 0.02 ± 0.43‰, 1σ). Cheshire Formation black shale sulfide samples measured in this study have δ34S values ranging from -2.11‰ to 2.39‰ (average 0.25 ± 1.08‰, 1σ) and near zero and solely positive Δ33S anomalies between 0.14‰ and 1.17‰ (average 0.56 ± 0.29‰, 1σ). Moreover, Δ36S/Δ33S in the two formations are comparable with a slope of -1.38 (Manjeri Formation) and -1.67 (Cheshire

  2. Rb–Sr and Sm–Nd isotope systematics and geochemical studies on metavolcanic rocks from Peddavura greenstone belt: Evidence for presence of Mesoarchean continental crust in easternmost part of Dharwar Craton, India

    Indian Academy of Sciences (India)

    M Rajamanickam; S Balakrishnan; R Bhutani


    Linear, north–south trending Peddavura greenstone belt occurs in easternmost part of the Dharwar Craton. It consists of pillowed basalts, basaltic andesites, andesites (BBA) and rhyolites interlayered with ferruginous chert that were formed under submarine condition. Rhyolites were divided into type-I and II based on their REE abundances and HREE fractionation. Rb–Sr and Sm–Nd isotope studies were carried out on the rock types to understand the evolution of the Dharwar Craton. Due to source heterogeneity Sm–Nd isotope system has not yielded any precise age. Rb–Sr whole-rock isochron age of 2551 ± 19 (MSWD = 1.16) Ma for BBA group could represent time of seafloor metamorphism after the formation of basaltic rocks. Magmas representing BBA group of samples do not show evidence for crustal contamination while magmas representing type-II rhyolites had undergone variable extents of assimilation of Mesoarchean continental crust (< 3.3 Ga) as evident from their initial Nd isotope values. Trace element and Nd isotope characteristics of type I rhyolites are consistent with model of generation of their magmas by partial melting of mixed sources consisting of basalt and oceanic sediments with continental crustal components. Thus this study shows evidence for presence of Mesoarchean continental crust in Peddavura area in eastern part of Dharwar Craton.

  3. The 3.26-3.24 Ga Barberton asteroid impact cluster: Tests of tectonic and magmatic consequences, Pilbara Craton, Western Australia (United States)

    Glikson, Andrew; Vickers, John


    The location in the Barberton Greenstone Belt (Kaapvaal Craton) of ∼3.26-3.24 Ga asteroid impact ejecta units at, and immediately above, a sharp break between a > 12 km-thick mafic-ultramafic volcanic crust (Onverwacht Group ∼3.55-3.26 Ga, including the ∼3.298 > 3.258 Ga Mendon Formation) and a turbidite-felsic volcanic rift-facies association (Fig Tree Group ∼3.258-3.225 Ga), potentially represents the first documented example of cause-effect relations between extraterrestrial bombardment and major tectonic and igneous events [D.R. Lowe, G.R. Byerly, F. Asaro, F.T. Kyte, Geological and geochemical record of 3400 Ma old terrestrial meteorite impacts, Science 245 (1989) 959-962; D.R. Lowe, G.R. Byerly, F.T. Kyte, A. Shukolyukov, F. Asaro, A. Krull, Spherule beds 3.47-3.34 Ga-old in the Barberton greenstone belt, South Africa: a record of large meteorite impacts and their influence on early crustal and biological evolution, Astrobiology 3 (2003) 7-48; A.Y. Glikson, The astronomical connection of terrestrial evolution: crustal effects of post-3.8 Ga mega-impact clusters and evidence for major 3.2 ± 0.1 Ga bombardment of the Earth-Moon system, J. Geodyn. 32 (2001) 205-229]. Here we correlate this boundary with a contemporaneous break and peak magmatic and faulting events in the Pilbara Craton, represented by the truncation of a 3.255-3.235 Ga-old volcanic sequence (Sulphur Springs Group-SSG) by a turbidite-banded iron formation-felsic volcanic association (Pincunah Hill Formation, basal Gorge Creek Group). These events are accompanied by ∼3.252-3.235 Ga granitoids (Cleland plutonic suite). The top of the komatiite-tholeiite-rhyolite sequence of the SSG is associated with a marker chert defined at 3.238 ± 3-3.235 ± 3 Ga, abruptly overlain by an olistostrome consisting of mega-clasts of felsic volcanics, chert and siltstone up to 250 × 150 m-large, intercalated with siliciclastic sedimentary rocks and felsic volcanics (Pincunah Hill Formation-basal Gorge

  4. Timing of deposition and provenance of stromatolitic carbonates from the 2.7 Ga. Belingwe Greenstone Belt/Zimbabwe Craton: constraints from Pb-Pb and Sm-Nd systematics

    International Nuclear Information System (INIS)

    Full text: Pb-Pb isochron ages have been obtained for stromatolitic limestones from the late Archaean Belingwe Greenstone Belt, providing direct age constraints on the deposition of these shallow water marine sediments. Samples from the Manjeri Formation and stratigraphically upper Cheshire Formation yield ages of 2700±49 Ma (MSWD = 13) and 2543±53 Ma (MSWD 5.6), respectively. These data are in agreement with published U-Pb zircon and Pb-Pb whole rock ages of stratigraphically enclosing volcanics, and we interpret our Pb-Pb ages as the timing of diagenesis and minimum age of carbonate precipitation. A 2400±53 Ma age (MSWD = 0.66) for one sample from the Cheshire Formation is considered to be unrelated to a depositional/ diagenetic event. We infer that this age may reflect a craton wide thermal/ chemical disturbance event or tectonic activity along the crustal-scale Mtshingwe fault. Carbonate samples collected from a sheared contact have also been subjected to Pb isotope analysis in an attempt to obtain absolute age constraints on deformation. Geological information precludes this age from being meaningful and this, along with a high MSWD value, indicates open-system behaviour and/or mixing relationships between isotopic end-members. A step-dissolution procedure using dilute acetic and hydrochloric acids has been applied to sub-samples from individual hand-specimens. This technique enables to recover radiogenic and common Pb, and thus is of particular utility where single hand-specimens are to be dated. Calculated model μ-values for Manjeri and Cheshire limestones are 8.4±0.02 and 9.02±0.01, similar to values for ca. 3.5 and 2.9 Ga.- old Archaean basement units adjacent to the Belingwe Belt. Negative ε-Nd (T-deposition) and ∫Sm/Nd suggest derivation of the REE from old, LREE enriched continental crust. 2-stage Nd model ages for the carbonates indicate that precursor rocks were extracted from the mantle 3.5 - 3.8 Ga. (Cheshire Formation) and 3.3 Ga. (Manjeri

  5. Isotope age of the rare metal pegmatite formation in the Kolmozero-Voron'ya greenstone belt (Kola region of the Fennoscandian shield): U-Pb (TIMS) microlite and tourmaline dating (United States)

    Kudryashov, Nikolay; Lyalina, Ludmila; Mokrushin, Artem; Zozulya, Dmitry; Groshev, Nikolay; Steshenko, Ekaterina; Kunakkuzin, Evgeniy


    The Kolmozero-Voron'ya greenstone belt is located in the central suture zone, which separates the Murmansk block from the Central-Kola and the Keivy blocks. The belt is represented by volcano-sedimentary rocks of Archaean age of 2.9-2.5 Ga. Rare metal pegmatites (Li, Cs with accessory Nb, Ta, and Be) occur among amphibolite and gabbroid intrusions in the northwestern and southeastern parts of the belt. According to the Rb-Sr data, the age of pegmatites was considered to be 2.7 Ga. Until recently there was no generally accepted point of view on the origin of pegmatites. Now we have isotopic data for a range of rock complexes that could pretend to be parental granites for the rare metal pegmatites. These are granodiorites with the zircon age of 2733±Ma, and microcline and tourmaline granites, which Pb-Pb isochronal age on tourmaline from the tourmaline granite located near the deposit is estimated to be 2520±70 Ma. The pegmatite field of the Vasin Myl'k deposit with the lepidolite--albite--microcline--spodumene--pollucite association is located among amphibolites in the northwestern part of the belt. The deposit is represented by subparallel low-angle zoned veins up to 220 m long and 5 m thick dipping in the southeastern direction at an angle of 10° too 30°. The minerals of the columbite--tonalite group from Vasin Myl'k deposit include microlite, simpsonite, and torolite, and are the oldest among different minerals represented by several generations in pegmatites under consideration. Zircons from the pegmatites are mostly represented by crystals with the structure affected by the action of fluids that put certain restrictions on its use as a geochronometer of the crystallization process. Microlite from the pegmatite taken from the dump of a prospecting drill hole was used for U--Pb (TIMS). The mineral is represented by 0.5--1.0 mm long euhedral octahedral crystals. It is brown in color, and transparent. The microlite crystals were preliminarily cleaned from

  6. Geodynamic evolution of the West Africa between 2.2 and 2 Ga: the Archaean style of the Birimian greenstone belts and the sedimentary basins in northeastern Ivory-Coast; Evolution de l`Afrique de l`Ouest entre 2,2 Ga et 2 Ga: le style archeen des ceintures vertes et des ensembles sedimentaires birimiens du nord-est de la Cote-d`Ivoire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, M.; Pouclet, A. [Orleans Univ., 45 (France); Delor, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Simeon, Y. [ANTEA, 45 - Orleans (France); Alric, G. [Etablissements Binou, 27 - Le Mesnil-Fuguet (France)


    The litho-structural features of Palaeo-proterozoic terrains of northeastern Ivory-Coast, greenstones belts and then sedimentary (basin Birimian), are similar to those of Archaean terrains. Their early deformation is only voluminal deformation due to granitoid intrusions, mainly between 2.2 and 2.16 Ga. The shortening deformation (main deformation) is expressed by right folds and transcurrent shear zones ca 2.1 Ga. Neither thrust deformation nor high pressure metamorphic assemblages are known. This pattern of flexible and hot crust, at least between 2.2 and 2.16 Ga, is pole apart to a collisional pattern, proposed for West African Craton by some authors. The Archaean/Palaeo-proterozoic boundary would not represent a drastic change of the geodynamic evolution of the crust. (authors). 60 refs., 5 figs., 6 photos.

  7. Archaean crustal evolution in eastern Finland : New geochronological and geochemical constraints from the Kuhmo terrain and the Nurmes belt


    KÀpyaho, Asko


    This thesis summarises the results of four original papers concerning U-Pb geochronology and geochemical evolution of Archaean rocks from the Kuhmo terrain and the Nurmes belt, eastern Finland. The study area belongs to a typical Archaean granite-greenstone terrain, composed of metavolcanic and metasedimentary rocks in generally N-S trending greenstone belts as well as a granitoid-gneiss complex with intervening gneissic and migmatised supracrustal and plutonic rocks. U-Pb data on migmatite m...

  8. Apartheid's Alcatraz: The Barberton Prison Complex During the Early 1980s - Part One


    Stephen Allister Peté.


    The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this a...

  9. Apartheid's Alcatraz: the Barberton Prison Complex during the early 1980s - Part two


    Stephen Allister Peté.


    The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this a...

  10. Geology of East Egypt greenstone field in Neoproterozoic isoand arc: Reconstruction of Iron formation sedimentary environment. (United States)

    Kiyokawa, S.; Suzuki, T.


    Geology of East Egypt greenstone-granit belt which is northern part of Nubia shield was identified neoproterozoic island arc amalgamated sections. There are several iron formation within these greenstone belt. Age data shows this iron formation may be overlaped during 700 Ma Snowball period, how ever, there is no detail report of well preserved ice related evidences. We now started detail field work for identified tectonic reconstruction, original stratigraphy around Iron formation and sedimentary environment during the iron formation sedimentation area. East Egyptian shield was divided three geology, Proterozoic greenstone complex, 700-600 Granitic domes and cover sequence (Hammamet Group). We focus three area to identified sedimentary environment of iron sedimentation. Along the north-south trend of Wadi EL Dabban area are, we named Wadi branch as West site is RW-0 ~ 12, East site is RE-0 ~ 12 from north to south. Northern area is structurally moderate, southern portion is north dipping. Southern portion was intruded by granite and several place contain granitic dikes. Northeast to eastern area are identified younger sedimentary sequence (Hammamat Group) which is unconformablly overlay on the other iron formation bearing greenstone belt. Structurally these area is divided four units. Wadi was divided by right-lateral strike-ship fault. The displacement are more than 3 km. Also north dipping faults are identified.East-West trend fault are divided two units. It is divided NE, SE, NW and NS units.SW unit is most well preserved thick sequence of the Iron formation. SW unit is well preserved iron formation sequence within thick volcaniclastics. This unit mostly north dipping around 40-60 degree. Structural repetition in not well understand. Reconstract stratigraphy in this unit is at least 4000m in thickness. 5 member is identified in this sequence. Several thin iron formations are observed with in pillow lava and volcaniclastic sequence. These very thick

  11. Granite-greenstone terranes in the Pilbara Block, Australia, as coeval volcano-plutonic complexes: Evidence from U-Pb zircon dating of the Mount Edgar Batholith

    International Nuclear Information System (INIS)

    The Mount Edgar Batholith in the Pilbara Block, Western Australia, consists, in part, of a gneiss complex that resembles other Archean high-grade gneiss terranes. The complex is extensively intruded by variably foliated granitoids which also intrude the surrounding greenstone succession, the Warrawoona Group. The contact between the greenstone belt and the gneiss complex is tectonic. Field evidence indicates that the banded gneisses are the oldest part of the batholith; zircon U-Pb ages for three samples are 3429±13 Ma, ≥ 3443±10 Ma and 3448±8 Ma, all very similar to the age of zircons in the felsic volcanic rocks near the base of the greenstone succession. Two granitoids, representing pre- and post-tectonic phases respectively, give zircon ages of 3304±10 Ma and 3314±13 Ma, thereby constraining the major structural events to be contemporary with granite magmatism, consistent with a diapiric model for the tectonic evolution of the batholith. These ages are similar to the zircon age for terminal volcanism in the Warrawoona Group, but are ≅ 100 Ma older than the precisely-defined Rb-Sr whole-rock ages obtained throughout the batholith. Batholith-wide resetting or late closure of Rb-Sr isotopic systems is implied, possibly associated with late fluid circulation. The temporal coincidence between plutonism and volcanism in the Mount Edgar region strongly suggests that the greenstone succession contains the extrusive equivalents of both the ≅ 3300 Ma granites and the ≅ 3440 Ma gneisses in the batholith. The isotopic evidence, combined with the structural data, indicates that the granites cannot be derived from the surrounding greenstone belt. Further, there is no compelling evidence for a sialic basement to the greenstone succession. (orig.)

  12. Microstructural analysis of a subhorizontal gold-quartz vein deposit at Donalda,Abitibi greenstone belt,Canada: Implications for hydrodynamic regime%加拿大Abitibi绿岩带Donalda金矿近水平含金石英脉的显微构造分析及其对成矿流体动力学的指示

    Institute of Scientific and Technical Information of China (English)

    池国祥; Jayanta Guha


    位于加拿大Abitibi绿岩带南部的Donalda金矿床主要由近水平的、与剪切带近垂直的含金石英脉组成,矿脉厚度0.3~0.5m,含大量与脉壁平行的条带,指示多期次裂隙扩张和矿物沉淀。原生石英c-轴方位测量显示石英生长方向垂直于脉壁,指示断裂属张性,矿物沉淀属空间充填。显微裂隙、细脉及流体包裹体面(FIPs)的方位测量指示原生矿物受到了近直立的最大主压应力(σ1)作用,与区域性的、近水平的南北向挤压应力不符。这一矛盾现象可用流体压力在超静岩和静水压力之间周期性变化及近水平断裂的周期性张开与闭合来解释。当流体压力大于静岩压力时,断裂张开,原生矿物沉淀,而当流体压力减小时,断裂上盘往下垮,两盘突出的矿物碰撞、碾压形成与脉壁平行的变形条带。由于断裂两盘岩石不是沿整条断裂都互相接触,两盘相顶部分承受的垂直应力大于水平方向的挤压应力,这就解释了为什么显微构造指示近直立的最大主压应力(σ1)。这个流体-构造模式支持断层阀模式,并且无须改变区域应力场就可解释脉体内局部主压应力的变化。%The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists mainly of a subhorizontal gold-quartz vein perpendicular to subvertical shear zones.The 0.3-0.5 m thick vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening and mineral precipitation.Measurement of the c-axis of primary growth quartz indicates that quartz preferentially grew perpendicular to the fracture,suggesting open space filling and/or extensional nature of the fracture.Measurement of the orientations of microfractures,veinlets and fluid-inclusion planes(FIPs) crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum principal stress(σ 1),which is

  13. Geochemical evolution of magmatism in Archean granite-greenstone terrains (United States)

    Samsonov, A. V.; Larionova, Yu. O.


    Evolution of Archean magmatism is one of the key problems concerning the early formation stages of the Earth crust and biosphere, because that evolution exactly controlled variable concentrations of chemical elements in the World Ocean, which are important for metabolism. Geochemical evolution of magmatism between 3.5 and 2.7 Ga is considered based on database characterizing volcanic and intrusive rock complexes of granite-greenstone terrains (GGT) studied most comprehensively in the Karelian (2.9-2.7 Ga) and Kaapvaal (3.5-2.9 Ga) cratons and in the Pilbara block (3.5-2.9 Ga). Trends of magmatic geochemical evolution in the mentioned GGTs were similar in general. At the early stage of their development, tholeiitic magmas were considerably enriched in chalcophile and siderophile elements Fe2O3, MgO, Cr, Ni, Co, V, Cu, and Zn. At the next stage, calc-alkaline volcanics of greenstone belts and syntectonic TTG granitoids were enriched in lithophile elements Rb, Cs, Ba, Th, U, Pb, Nb, La, Sr, Be and others. Elevated concentrations of both the “crustal” and “mantle-derived” elements represented a distinctive feature of predominantly intrusive rocks of granitoid composition, which were characteristic of the terminal stage of continental crust formation in the GGTs, because older silicic rocks and lithospheric mantle were jointly involved into processes of magma generation. On the other hand, the GGTs different in age reveal specific trends in geochemical evolution of rock associations close in composition and geological position. First, the geochemical cycle of GGT evolution was of a longer duration in the Paleoarchean than in the Meso-and Neoarchean. Second, the Paleoarche an tholeiitic associations had higher concentrations of LREE and HFSE (Zr, Ti, Th, Nb, Ta, Hf) than their Meso-and Neoarchean counterparts. Third, the Y and Yb concentrations in Paleoarchean calc-alkaline rock associations are systematically higher than in Neoarchean rocks of the same type

  14. Apartheid's Alcatraz: The Barberton Prison Complex During the Early 1980s - Part Two

    Directory of Open Access Journals (Sweden)

    Stephen Allister Peté.


    Full Text Available The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this article is on the treatment of "normal" as opposed to "political" prisoners during the period in question, allowing the "voices" of ordinary prisoners – often sidelined and silenced – to be brought to the fore. The Barberton Prison Complex is examined through the lens of public discourse, as reflected in a wide range of South African newspapers published at the time. By analysing a large number of reports dealing with events at Barberton during the period in question, in both English and Afrikaans language newspapers, as well as in both politically conservative and politically liberal newspapers, this article attempts to capture both the "smell" and the "feel" of what it was like to be imprisoned in one of apartheid's toughest prison complexes. Furthermore, this article seeks to show that – despite legislative measures restricting the publication of information on conditions inside apartheid prisons – the press was able to provide a steady stream of information to the South African public on the shocking events which occurred at Barberton during the period in question. Part Two of the article examines a string of violent incidents which occurred within the Barberton Prison Complex during the course of 1983, leading to nine inmate deaths. The response of the authorities to this orgy of violence at Barberton is discussed, including the findings of a committee of enquiry. It is concluded that the events at Barberton during the early 1980s were

  15. Late Archean intermediate-felsic magmatism of the South Vygozersky and Kamennozersky greenstone structures of Central Karelia (United States)

    Myskova, T. A.; Zhitnikova, I. A.; L'vov, P. A.


    The geochemistry and zircon geochronology (U-Pb, SHRIMP-II) of Late Archean intermediate-felsic dikes and plagiogranites of the Shilossky massif of the South Vygozersky and Kamennozersky greenstone belts of Central Karelia were studied. Subvolcanic rocks of the dike complex vary in composition from andesitobasalts to rhyolites, in structural-textural peculiarities, and in the formation age, from 2862 ± 8 to 2785 ± 15 Ma. Compositionally and geochronologically (2853 ± 11 Ma), plagiogranites of the Shilossky massif of the South Vygozersky greenstone belts are close to the most ancient dacite and granodiorite porphyry dikes. Dikes intruded synchronously with intrusion of plagiogranites over a period of at least 70 m.y. Geochronologically, subvolcanic rocks of the dike complex and plagiogranites of the Shilossky massif are similar to granitoids of the TTG assemblages of I- and M-type granites. The Sm-Nd model age of some dikes (2970-2880 Ma) is close to the age of rock crystallization, which is evidence in favor of juvenile origin of magma. Dikes with more ancient model age (3050 Ma) are presumed to contain crustal material. Variations in age and ɛNd (from -2.7 to +2.9) indicate the absence of a unified magmatic source.

  16. Apartheid's Alcatraz: The Barberton Prison Complex During the Early 1980s - Part One

    Directory of Open Access Journals (Sweden)

    Stephen Allister Peté


    Full Text Available The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this article is on the treatment of "normal" as opposed to "political" prisoners during the period in question, allowing the "voices" of ordinary prisoners – often sidelined and silenced – to be brought to the fore. The Barberton Prison Complex is examined through the lens of public discourse, as reflected in a wide range of South African newspapers published at the time. By analysing a large number of reports dealing with events at Barberton during the period in question, in both English and Afrikaans language newspapers, as well as in both politically conservative and politically liberal newspapers, this article attempts to capture both the "smell" and the "feel" of what it was like to be imprisoned in one of apartheid's toughest prison complexes. Furthermore, this article seeks to show that – despite legislative measures restricting the publication of information on conditions inside apartheid prisons – the press was able to provide a steady stream of information to the South African public on the shocking events which occurred at Barberton during the period in question. Part One of this article deals with the deaths of three prisoners and the injury of many others during a day of violence at the Barberton prison farm on 29 December 1982, as well as the broader political implications of the criminal trial - known as the "heat exhaustion trial" - which followed. It is contended that the events surrounding the infamous "heat exhaustion trial" may be seen

  17. Silica precipitation triggered by clastic sedimentation in the Archean : new petrographic evidence from cherts of the Kromberg type section, South Africa


    M. Ledevin; Arndt, N.; Simionovici, A.; Jaillard, Etienne; Ulrich, M.


    The Kromberg Formation (ca. 3432 Ma) in the Barberton Greenstone Belt, South Africa, contains well-preserved chert beds at the tops of turbidite deposits. At the interface, siltstone, which consist of Kfeldspar, K-mica, microquartz with minor lithic fragments and heavy minerals, grades into chert, which consists of microquartz and minor K-mica (

  18. Compositional variations in the Mesoarchean chromites of the Nuggihalli schist belt, Western Dharwar Craton (India): calculations of parental melts and implications for tectonic settings

    DEFF Research Database (Denmark)

    Mukherjee, R; Mondal, S K; Rosing, Minik Thorleif;


    The chromite deposits in the Archean Nuggihalli schist belt are part of a layered ultramafic-mafic sequence within the Western Dharwar Craton of the Indian shield. The 3.1-Ga ultramafic-mafic units occur as sill-like intrusions within the volcano-sedimentary sequences of the Nuggihalli greenstone...

  19. Compositional variations in the Mesoarchean chromites of the Nuggihalli schist belt, Western Dharwar Craton (India): potential parental melts and implications for tectonic setting

    DEFF Research Database (Denmark)

    Mukherjee, R.; Mondal, S.K.; Rosing, M.T.;


    The chromite deposits in the Archean Nuggihalli schist belt are part of a layered ultramafic-mafic sequence within the Western Dharwar Craton of the Indian shield. The 3.1-Ga ultramatic-mafic units occur as sill-like intrusions within the volcano-sedimentary sequences of the Nuggihalli greenstone...

  20. On the metamorphic history of an Archaean granitoid greenstone terrane, East Pilbara, Western Australia, using the 40Ar/39Ar age spectrum technique

    International Nuclear Information System (INIS)

    Age spectrum analyses of blue-green hornblendes from amphibolites from the Western Shaw Belt, East Pilbara, Western Australia, indicate an age of at least 3200 Ma for early regional metamorphism. Ages on hornblende and muscovite from the narrow contact zone with the adjacent Yule Batholith probably data updoming of the granitoid gneiss terranes at 2950 Ma. Hornblendes from within the Shaw Batholith and from a contact zone of a post-tectonic granitoid yield ages of 2840-2900 Ma, indicating either prolonged high temperatures within the granitoid gneiss terranes or a separate thermal pulse associated with the intrusion of post-tectonic granitoids. The preservation of very old hornblendes in a narrow greenstone belt surrounded by massive granitoid gneiss domes indicates that remarkable contrasts in metamorphic geotherms existed over short distances during the Late Archaean, suggesting that updoming occurred during a period of rapid tectonism. (orig.)

  1. Mesoarchean sanukitoid rocks of the Rio Maria Granite-Greenstone Terrane, Amazonian craton, Brazil (United States)

    de Oliveira, Marcelo Augusto; Dall'Agnol, Roberto; Althoff, Fernando Jacques; da Silva Leite, Albano Antonio


    The Archean sanukitoid Rio Maria Granodiorite yielded zircon ages of ˜2.87 Ga and is exposed in large domains of the Rio Maria Granite-Greenstone Terrane, southeastern Amazonian craton. It is intrusive in the greenstone belts of the Andorinhas Supergroup, in the Arco Verde Tonalite and Caracol Tonalitic Complex (older TTGs). Archean potassic leucogranites, younger TTGs and the Paleoproterozoic granites of Jamon Suite are intrusive in the Rio Maria Granodiorite. The more abundant rocks of the Rio Maria Granodiorite have granodioritic composition and display medium to coarse even-grained textures. These rocks show generally a gray color with greenish shades due to strongly saussuritized plagioclase, and weak WNW-ESE striking foliation. The significant geochemical contrasts between the occurrences of Rio Maria Granodiorite in different areas suggest that this unit corresponds in fact to a granodioritic suite of rocks derived from similar but distinct magmas. Mingling processes involving the Rio Maria Granodiorite and similar mafic to intermediate magmas are able to explain the constant occurrence of mafic enclaves in the granodiorite. The associated intermediate rocks occur mainly near Bannach, where mostly quartz diorite and quartz monzodiorite are exposed. The dominant rocks are mesocratic, dark-green rocks, with fine to coarse even-grained texture. The Rio Maria Granodiorite and associated intermediate rocks show similar textural and mineralogical aspects. They follow the calc-alkaline series trend in some diagrams. However, they have high-Mg#, Cr, and Ni conjugate with high contents of large ion lithophile elements (LILEs), typical of sanukitoids series. The patterns of rare earth elements of different rocks are similar, with pronounced enrichment in light rare earth elements (LREEs) and strong to moderate fractionation of heavy rare earth elements (HREEs). Field aspects and petrographic and geochemical characteristics denote that the granodiorites and

  2. Barberton-Phalaborwa airborne geophysical survey (25/78) - preliminary report on airborne radiometric data

    International Nuclear Information System (INIS)

    Forty-two uranium and mixed uranium and thorium anomalies were selected from the analogue radiometric records generated during theBarberton-Phalaborwa airborne geophysical survey. Thirty-eight of the anomalies plotted over rocks of the Timeball Hill and Daspoort Formations, and ground follow-up work is recommended for these anomalies. Two more anomalies probably originate from rocks of the Palabora Igneous Complex, another anomaly overlies a diabase intrusive, and the remaining anomaly appears related to an outlier of Ecca Group rocks

  3. Great Belt

    DEFF Research Database (Denmark)

    Sørensen, Carsten S.; Kristensen, Per S.; Erichsen, Lars

    This paper describes aspects of the soil investigations and geotechnical evaluations for the foundation design of the 6.6 km long Great Belt West Bridge. The gravity foundations rest predominantly on glacial tills and pre-quaternary limestone. Special investigations for assessment of the soil pro...... properties for ship impact and ice loading are described briefly, and first experiences from settlement monitoring of the structure during erection are presented....

  4. Barberton-Phalaborwa airborne geophysical survey (25/78): anomaly supplement to preliminary report on airborne radiometric data

    International Nuclear Information System (INIS)

    Photo-copies of the 42 uranium anomalies selected from the analogue spectrometer records of block 25/78 (Barberton-Phalaborwa) are presented for reference during ground follow-up operations. It is expected that the data in the report will be used during ground follow-up operations. The systems for anomaly selection and anomaly numbering are discussed

  5. Earth's Archean Impact Record In The ICDP Drilling "Barberton Mountain Land". (United States)

    Fritz, Jörg; Schmitt, Ralf-Thomas; Reimold, Uwe; Koeberl, Christian; Mc Donald, Ian; Hofmann, Axel; Luais, Beatrice


    The marine meta-sedimentary successions in the "Barberton Mountain Land" are formed by Archean volcanic and sedimentary rocks including the oldest known impact ejecta layers on Earth. The chemical signature (high iridium concentrations, chromium isotopic ratios) of some of these up to tens of cm thick Archean spherule layers advocate that these ejecta deposits represent mainly extraterrestrial material [1]. These ejecta layers contain millimetre sized spherules that are larger and accumulated thicker layers compared to any impact ejecta layer known from Phanerozoic sediments, including the global ejecta layer of the Chicxulub impact catering event terminating the Mesozoic era of Earth's history [2]. The Archean spherule layers are interpreted as products of large impacts by 20 to >100 km diameter objects [3, 4]. Identifying traces of mega-impacts in Earth's ancient history could be of relevance for the evolution of atmosphere, biosphere, and parts of the Earth's crust during that time. In addition, recognizing global stratigraphic marker horizons is highly valuable for inter-correlating sedimentary successions between Archean cratons [5]. However estimates regarding size of the impact event and correlations between the different outcrops in the Barberton mountain land are complicated by post depositional alterations of the tectonically deformed sediments [6, 7]. The relatively fresh samples recovered from below the water table during the 2011-2012 ICDP drilling "Barberton Mountain Land" are promising samples to investigate and to discriminate primary and secondary features of these rare rocks. We plan to conduct 1) petrographic, micro-chemical and mineralogical characterization of the impact ejecta layers, 2) bulk chemical analyses of major and trace elements, and 3) LAICP- MS elemental mapping of platinum group element (PGE) distributions. and elemental analyses of moderately siderophile elements. This aims at 1) characterization of the ejecta layers, 2

  6. Age of the Mulcahy Lake intrusion, northwest Ontario, and implications for the evolution of greenstone-granite terrains

    International Nuclear Information System (INIS)

    Zircon data from a 63 km2 layered mafic intrusion in the Wabigoon subprovince, the Mulcahy Lake gabbro, show that the gabbro crystallized at 2733.2(+1.0-0.9) Ma. The largely unaltered and unmetamorphosed gabbro intrudes tholeiites of the Crow Lake-Savant Lake greenstone belt which were generated over at least a 10 Ma time span. Rb-Sr and Sm-Nd data were obtained for pristine whole rock and mineral separates from the intrusion. The Rb-Sr data show disturbances in the system, particularly in the case of pyroxenes. Samples with low Rb/Sr ratios indicate an initial Sr ratio of 0.7007 for an age of 2733 Ma. The Sm-Nd age is 2744+-55 Ma, and an epsilon Nd value of +2.6+-1.2 indicates a light rare earth element depleted source. The Sm-Nd data shows less disturbance than the Rb-Sr data. Granitic and mafic intrusives with similar initial ratios occur 80 km to the south in the Quetico subprovince. Primary hornblende was analyzed for 40Ar/39Ar. The age obtained is 2703+-20 Ma, clearly younger than the zircon age indicating some argon loss. (orig.)

  7. Age range of formation of sedimentary-volcanogenic complex of the Vetreny Belt (the southeast of the Baltic Shield) (United States)

    Mezhelovskaya, S. V.; Korsakov, A. K.; Mezhelovskii, A. D.; Bibikova, E. V.


    As a result of studying the Vetreny Belt greenstone structure (the southeast of the Baltic Shield), zircons from terrigenous deposits of the Toksha Formation, underlying the section of the sedimentary-volcanogenic complex, and zircons of the Vetreny Belt Formation, deposits of which crown the section, were dated. The results of analysis of age data of detrital zircons from quartzites of the Toksha Formation indicate that Mesoarchean greenstone complexes and paleo-Archean granitogneisses of the Vodlozero Block (Karelia) were the provenance area from which these zircons were derived. The occurrence of the youngest zircons with age of 2654.3 ± 38.5 Ma is evidence that the formation of the Vetreny Belt, including the Toksha Formation, began no earlier than this time. Zircons from volcanic rocks of the Vetreny Belt yielded the age of 2405 ± 5 Ma. Thus, the age interval of the formation of the sedimentary-volcanogenic complex of the Vetreny Belt ranges from 2654.3 ± 38.5 to 2405 ± 5 Ma.

  8. Belt attachment and system

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abraham D.; Davidson, Erick M.


    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  9. The Glória quartz-monzodiorite: isotopic and chemical evidence of arc-related magmatism in the central part of the Paleoproterozoic Mineiro belt, Minas Gerais State, Brazil


    Ciro A. Ávila; Wilson Teixeira; Umberto G. Cordani; Héctor R. Barrueto; Ronaldo M. Pereira; Veridiana T.S. Martins; Liu Dunyi


    The Glória quartz-monzodiorite, one of the mafic plutons of the Paleoproterozoic Mineiro belt, is intrusive into banded gneisses, amphibolites, schists and phyllites of the Rio das Mortes greenstone belt, in the southern portion of the São Francisco Craton, State of Minas Gerais, Brazil. The Glória quartz-monzodiorite yields a SHRIMP U-Pb zircon age of 2188 ± 29 Ma, suggesting a tectonic relationship with the pre-collisional phase of the Mineiro belt. According to the Nd isotopic evide...

  10. Results of the ground follow-up of 34 airborne, radiometric anomalies in block 25/78, Barberton-Phalaborwa

    International Nuclear Information System (INIS)

    Thirty-four out of the 42 selected anomalies of the Barberton Phalaborwa airborne radiometric survey (block 25/78) were followed up in the field. The results of the survey show that none of the anomalies have any immediate economic potential. The highest values (up to 355 ppm eU3O8) were obtained over an anomaly on sheet 2430 DC, near Pilgrims Rest. The magnetic field of the ferruginous quartzites - over which most of the anomalies occur - affected both scintillometer and spectrometer results in several areas

  11. Geochemical variability in the green stone belts of Goias (Brazil): the Hidrolina and Crixas sequences

    International Nuclear Information System (INIS)

    The greenstone belts of Crixas and Hidrolina of Goias, Brazil are dismembered components of the same body or of originally adjacent belts. Their tectono-metamorphic history and stratigraphy is similar, as well as their igneous components (meta-komatiites, meta-basalts and felsic meta-volcanics). Chemically, they differ for the CaO and Al2O3 versus MgO trends and for the behaviour of many incompatible and compatible trace elements (Cr, Ni, Ti, Sc, Y, Zr, P). The difference in the trace element behaviour has been mainly attributed to a compositional and modal heterogeneity of the mantle source, which was probably spinel-richer at Crixas than at Hidrolina. The X-ray fluorescence analytical methods employed for major and trace elements determinations on the 120 Crixas samples were the same as used at Hidrolina. (author)

  12. Aspects of the Petrology and Geochemistry of Greenstones: with special reference to SW England and Wales

    Directory of Open Access Journals (Sweden)

    P.A. Floyd


    Full Text Available The use of texture, petrology and geochemistry of Neolithic greenstone hand axes, to determine provenance, is well established. However, as many UK greenstones are essentially meta-dolerites (mildly metamorphosed medium-grained basic rocks it is often necessary to consider the type and degree of alteration superimposed on the primary igneous mineralogy to establish different petrological groups of axes. In particular, alteration and texture can be highly variable in any one large outcrop that might have been used for the manufacture of axes. Similarly, geochemical fingerprinting of axes and subsequent comparison with known outcrops will only be successful if sufficient chemical data are available from any suspected source region when the full range of natural variation has been ascertained.



    Ramadan Elaiess


    The aim of this paper is to explore Greenstone open source digital library software which considered to be one of most essential open-source Content Management Systems (CMSs) that are available for use in creating, organizing, and managing Arabic content on the Internet. It focuses on the appropriateness of the system for Arabic content from different perspectives, such as its ability to support the Arabic language and to sustain and maintain different file formats. It also aims to examine Gr...

  14. Source heterogeneity for the major components of ~3.7 Ga banded iron formations (Isua Greenstone Belt, Western Greenland)

    DEFF Research Database (Denmark)

    Frei, Robert; Polat, Ali


    protocrustal landmass (eNd(3.7 Ga)   + 1.6). The validity of two different and periodically interacting water masses (an essentially two-component mixing system) in the deposition of alternating iron- and silica-rich layers is also reflected by systematic trends in germanium (Ge)/silicon (Si) ratios. These...

  15. An overview of the lithological and geochemical characteristics of the Mesoarchean (ca. 3075) Ivisaartoq greenstone belt, southern West Greenland

    DEFF Research Database (Denmark)

    Polat, A.; Frei, Robert; Appel, P.W.U.;


    Ca-plagioclase and are interpreted as anorthositic cumulates of the lower oceanic crust brought to the surface by upwelling gabbroic magmas. Alternatively, the inclusions may represent the xenoliths from older (>3075 Ma) anorthositic crust onto which the Ivisaartoq magmas were emplaced as an...

  16. Approche métallogénique du "Greenstone Belt" de Bogoin (RCA). Sa minéralisation en or


    Biandja, Jean


    La minéralisation aurifère primaire du secteur de Bogoin se présente sous forme d'un stockwerk quartzeux de direction N-S encaissé dans des roches vertes. Ces dernières appartiennent à une série métamorphique (limite faciès schistes verts-amphibolite) plissée en un synclinorium de direction N-S qui dessine un "doigt de gant" dans un vaste massif granito-gneissique. La foliation principale (SP) est plan axial de cette structure. L'ensemble est réputé archéen. Le synclinal s'ennoie vers le Sud ...

  17. Rare earth chemistry of gold-bearing sedimentary carbonate horizons from the Abitibi Greenstone Belt, Ontario, Canada

    International Nuclear Information System (INIS)

    The ankerite, gold ore bodies of the Dome Mine, Timmins, Ontario are interflow units, 1 to 3 m thick in a sequence of tholeiitic basalts. The units consist of discontinuous layers of ferroan dolomite, chert and pyroclastic material, and laminations of iron sulfides, tourmaline, and graphite. They have been interpreted as sediments on the basis of their internal structure. Seven Rare Earth elements (REE) (Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb) were determined by instrumental neutron activation analysis, on 10 samples of carbonate material from the ankerite units. The chondrite normalized REE plots have relatively flat patterns with, in some cases, positive Europium anomalies. The flat patterns suggest that the fluids from which the carbonate precipitated was in equilibrium with volcanic rocks of tholeiitic and komatiitic composition. The positive Europium anomalies imply that the fluids were reducing at times. Such patterns are characteristic of Archaean sediments and also the precipitates associated with the discharge of hydrothermal solutions from vents on the East Pacific Rise

  18. Age succession of metamorphism, paleovolcanism and granitoid magnetism processes in greenstone belts of Middle Dnieper region (Ukrainian shield)

    International Nuclear Information System (INIS)

    Time succession of paleovolcanism, granatoid magmatism and metamorphism process is considered on the basis of geological, petrological and geochronological data obtained using U-Pb isochronous method by accessory zircons. Paleovolcanism process prevailed 3200-3000 billions of years ago, granatoid magmatism-3100-2950 millions of years ago and regional metamorphism-3000-2840 millions of years ago

  19. Riding the belt

    Energy Technology Data Exchange (ETDEWEB)

    Potts, A.


    Recent developments in conveyor systems have focused on accessories rather than the belt itself. Radio frequency identification (RFID) is a technology using transponders embedded in conveyor belts and this is the latest development at the German firm Contitech. The system described in the articles developed with Moers, features transponders for cooling, controlling and monitoring conveyor belts. Other developments mentioned include a JOKI drum motor featuring a fully integrated gearbox and electric motor enclosed in a steel shell, from Interoll; a new scraper cleaning system from Hosch, new steel cord belting from Fenner, a conveying system for Schleenhain lignite opencast mine by FAM Foerdelantigen Magdeburg; new bearings from Nadella (the sales arm of Intersoll-Rand), an anti-shock belt transfer table from Rosta and new caliper disc brakes from GE Industrial.

  20. Cabacal belt, southern Amazon craton in Mato Grosso-Brazil: Implications for the tectonic evolution (more complications)

    International Nuclear Information System (INIS)

    The Amazon Craton covers an area of about 250000Km2 on the northern part of the South America. The Precambrim time history of the craton has been divided in geochronological provinces (Cordani et al. 1979; Teixeira et al. 1989; Tassinari et al. 1996; Tassinari and Macambira, 1999; and Santos et al. 2000). The Cabacal Belt covers an area of approximately 350 square kilometers in the southern region of the Amazon Craton, Mato Grosso-Brazil. It is a narrow NNW trending belt of greenchist to amphibolite grade volcano-sedimentary rocks intruded by plutonic rocks of tonalitic to granitic composition and mafic sills/dikes (Pinho et al., 1997). To the East it is bounded by Mesoproterozoic sediments of the Aguapei Group. To the West it is separated from the Araputanga Belt by a metamorphic complex, chiefly made of orthogneisses. The Cabacal Belt is one of the three NNW trending belts from the Alto Jauru Greenstone Belt. As a whole, the supracrustal rocks of the Cabacal Belt consist of three units: a basal unit comprising mafic lavas and breccias; a middle unit of felsic to intermediate metavolcanics rocks with interlayered tuffs and sediments; and a top unit of dacite-rhyodacit lavas, tuffs, and sediments (clastic and chemical). Monteiro et al. (1986) named these units as Mata Preta (MPF), Manuel Leme (MLF) and Rancho Grande (RGF) formations respectively. Leite et al. (1986) used the name Quatro Meninas Complex for the basic unit We analyzed zircons from seven samples in the Cabacal Belt, including samples from the volcano-sedimentary sequence, from intrusive bodies, and from the gneiss that separates the Cabacal Belt from the Araputanga Belt (au)

  1. Precambrian Cratons and Fold-Belts in Brazil: Overview (United States)

    Fuck, R.


    The main Precambrian terrains recognized in Brazil comprise the Amazonian, São Francisco and Rio de la Plata cratons, surrounded by Neoproterozoic Brasiliano fold belts, making up the Borborema, Mantiqueira and Tocantins provinces. The Amazonian craton comprises an Archean core, surrounded by Paleoproterozoic terrains (Maroni-Itacaiunas, Ventuari-Tapajós, Rio Negro-Juruena), which southwestwards give way to the Mesoproterozoic Rondoniano-San Ignacio and Sunsas belts, the latter thought to be related to the Grenville belt of North America. The São Francisco craton comprises several Archean blocks (Gavião, Serrinha, Jequié) amalgamated by the Paleoproterozoic high-grade Itabuna-Salvador-Curaçá orogen. The Rio de la Plata craton, largely covered by Phanerozoic strata, is made of Paleoproterozoic basement gneiss and several Paleoproterozoic greenstone belts. Other cratonic blocks are hidden below large Phanerozoic basins, like the Paranapanema and Parnaíba blocks below the Paraná and Parnaíba basins, respectively. Several smaller Archean/Paleoproterozoic blocks appear within the Brasiliano provinces: some were strongly reworked during the Neoproterozoic orogenic events (São José do Campestre, Pernambuco-Alagoas, Goiás, Guanhães, Juiz de Fora, Curitiba), others were only marginally affected (São Luiz, Rio Apa, Luís Alves). The Brasiliano provinces are the result of Neoproterozoic to early Paleozoic orogenic events within the framework of West Gondwana amalgamation. The Mantiqueira Province extends from eastern Brazil to southern Uruguay and includes the Araçuaí, Ribeira and Dom Feliciano fold belts, bordering the São Francisco, Paranapanema and Rio de la Plata cratons and surrounding the Luís Alves craton. The Tocantins province in central Brazil includes the Araguaia, Paraguay and Brasília fold belts, the former bordering the Amazonian craton, the second bordering both the southern Amazonian craton and the Rio Apa block, and the last established on

  2. Dynamic characteristics of conveyor belts

    Institute of Scientific and Technical Information of China (English)

    HOU You-fu; MENG Qing-rui


    The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and theological constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.

  3. The JET belt limiter

    International Nuclear Information System (INIS)

    A limiter with an effective area in contact with the plasma of about 16 m2 is presently being manufactured for installation in 1987. This belt limiter consists of two toroidal rings located above and below the equatorial plane of the vacuum vessel. Each of the two rings comprises a structure with water cooling pipes and fins welded to the pipes. The limiter material in contact with the plasma (graphite or beryllium) is inserted between fins in the form of tiles. The belt limiter is designed to handle up to 40 MW of total power at flux densities of 3 - 5 MW/m2 for 10 s and to permit rapid exchange of different limiter materials. The design and manufacture of the belt limiter and the results of thermomechanical analysis for different edge properties, power levels and shot repetition rates, are reported. (author)

  4. The jet belt limiter

    International Nuclear Information System (INIS)

    A limiter with an effective area in contact with the plasma of about 16 m/sup 2/ is presently being manufactured for installation in 1987. This belt limiter consists of two toroidal rings located above and below the equatorial plane of the vacuum vessel. Each of the two rings comprises a structure with water cooling pipes and fins welded to the pipes. The limiter material in contact with the plasma (graphite or beryllium) is inserted between fins in the form of tiles. The belt limiter is designed to handle up to 40 MW of total power at flux densities of 3 - 5 MW/m/sup 2/ for 10 s and to permit rapid exchange of different limiter materials. This paper describes the design and manufacture of the belt limiter and the results of thermomechanical analysis for different edge properties, power levels and shot repetition rates

  5. Coal belt options

    Energy Technology Data Exchange (ETDEWEB)



    Whether moving coal long distances overland or short distances in-plant, belt conveyors will always be in demand. The article reports on recent systems developments and applications by Beumer, Horizon Conveyor Equipment, Conveyor Dynamics, Doppelmayr Transport Technology, Enclosed Bulk Systems, ContiTech and Bateman Engineered Technologies. 2 photos.

  6. Metamorphic belts of Anatolia (United States)

    Oberhänsli, Roland; Prouteau, Amaury; Candan, Osman; Bousquet, Romain


    Investigating metamorphic rocks from high-pressure/low-temperature (HP/LT) belts that formed during the closure of several oceanic branches, building up the present Anatolia continental micro-plate gives insight to the palaeogeography of the Neotethys Ocean in Anatolia. Two coherent HP/LT metamorphic belts, the Tavşanlı Zone (distal Gondwana margin) and the Ören-Afyon-Bolkardağ Zone (proximal Gondwana margin), parallel their non-metamorphosed equivalent (the Tauride Carbonate Platform) from the Aegean coast in NW Anatolia to southern Central Anatolia. P-T conditions and timing of metamorphism in the Ören-Afyon-Bolkardağ Zone (>70?-65 Ma; 0.8-1.2 GPa/330-420°C) contrast those published for the overlying Tavşanlı Zone (88-78 Ma; 2.4 GPa/500 °C). These belts trace the southern Neotethys suture connecting the Vardar suture in the Hellenides to the Inner Tauride suture along the southern border of the Kirşehir Complex in Central Anatolia. Eastwards, these belts are capped by the Oligo-Miocene Sivas Basin. Another HP/LT metamorphic belt, in the Alanya and Bitlis regions, outlines the southern flank of the Tauride Carbonate Platform. In the Alanya Nappes, south of the Taurides, eclogites and blueschists yielded metamorphic ages around 82-80 Ma (zircon U-Pb and phengite Ar-Ar data). The Alanya-Bitlis HP belt testifies an additional suture not comparable to the northerly Tavşanlı and Ören-Afyon belts, thus implying an additional oceanic branch of the Neotethys. The most likely eastern lateral continuation of this HP belt is the Bitlis Massif, in SE Turkey. There, eclogites (1.9-2.4 GPa/480-540°C) occur within calc-arenitic meta-sediments and in gneisses of the metamorphic (Barrovian-type) basement. Zircon U-Pb ages revealed 84.4-82.4 Ma for peak metamorphism. Carpholite-bearing HP/LT metasediments representing the stratigraphic cover of the Bitlis Massif underwent 0.8-1.2 GPa/340-400°C at 79-74 Ma (Ar-Ar on white mica). These conditions compares to the Tav

  7. Infrared Kuiper Belt Constraints

    International Nuclear Information System (INIS)

    We compute the temperature and IR signal of particles of radius a and albedo α at heliocentric distance R, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of COBE DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance R, particle radius a, and particle albedo α. We then apply these results to a recently developed picture of the Kuiper belt as a two-sector disk with a nearby, low-density sector (40< R<50 endash 90 AU) and a more distant sector with a higher density. We consider the case in which passage through a molecular cloud essentially cleans the solar system of dust. We apply a simple model of dust production by comet collisions and removal by the Poynting-Robertson effect to find limits on total and dust masses in the near and far sectors as a function of time since such a passage. Finally, we compare Kuiper belt IR spectra for various parameter values. Results of this work include: (1) numerical limits on Kuiper belt dust as a function of (R, a, α) on the basis of four alternative sets of constraints, including those following from recent discovery of the cosmic IR background by Hauser et al.; (2) application to the two-sector Kuiper belt model, finding mass limits and spectrum shape for different values of relevant parameters including dependence on time elapsed since last passage through a molecular cloud cleared the outer solar system of dust; and (3) potential use of spectral information to determine time since last passage of the Sun through a giant molecular cloud. copyright copyright 1999. The American Astronomical Society

  8. Belt-up!

    Energy Technology Data Exchange (ETDEWEB)

    Woof, M.


    Advanced control systems, improved materials and new dust control systems have turned the humble conveyor belt into a sophisticated method for transporting materials. RJB Mining has improved productivity at the Price of Wales colliery in Yorkshire, UK, with the installation of Alstom`s VDM drive system; Qualter Hall`s upgraded conveyor system at the Rugely Power Station in the UK is proving its ability to minimise coal spillage. The article highlights advances by several manufacturers in conveyor technology. 5 photos.

  9. Technical Assessment of Greenstone toward Development of Digital Libraries in Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hassanzadeh


    Full Text Available Lack of integrated software is serious obstacle toward the development of digital libraries in Iran. Considering the problem, this research focused on Greenstone digital library software (GDLS to investigate its technical capabilities toward creating and managing digital collections in Iranian libraries. The study was conducted through evaluation research using a 9-spectrums checklist in two phases. In the first stage, experts from library and information science and computer science and in second stage, three user groups (with PhD, MA and BA degrees completed the checklist against capabilities of GDLS. Findings indicated that, there was no significant difference between two groups of specialist about capabilities of GDLS. Analyzing three user groups also approved GDLS competencies at this respect. There were some technical errors and bugs that experts proposed to be corrected toward best fitness of GDLS to Iranian collections.

  10. Lap belt injuries in children.

    LENUS (Irish Health Repository)

    McGrath, N


    The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

  11. An Archean Geomagnetic Reversal in the Kaap Valley Pluton, South Africa (United States)

    Layer; Kroner; McWilliams


    The Kaap Valley pluton in South Africa is a tonalite intrusion associated with the Archean Barberton Greenstone Belt. Antipodal paleomagnetic directions determined from the central and marginal parts of the pluton record a geomagnetic reversal that occurred as the pluton cooled. The age of the reversal is constrained by an 40Ar/39Ar plateau age from hornblende at 3214 +/- 4 million years, making it the oldest known reversal. The data presented here suggest that Earth has had a reversing, perhaps dipolar, magnetic field since at least 3.2 billion years ago. PMID:8688075

  12. Belt conveyor for recycle aggregate


    Bezrodný, Roman


    This bachelor thesis deals with the belt conveyor for the transport of recycled aggregate in an oblique direction. The aim is to find constructional solutions to the belt conveyor for the assigned transport capacity of 95 000 kg per hour, and the assigned axial distance of 49 m and different height of 12 m. The thesis contains a brief description of the belt conveyor and a description of basic constructional components. It also contains a functional calculation of the capacity and forces acco...

  13. Gold and uranium metallogenesis in the framework of Neo-proterozoic crust growth and differentiation: example of the Mayo-Kebbi Massif (Chad) in the Central Africa Orogenic belt

    International Nuclear Information System (INIS)

    The Mayo Kebbi massif located in southwestern Chad between the Congo craton in the South, the West African craton in the west and the Sahara meta-craton to the east exposes a segment of Neo-proterozoic juvenile crust accreted in the Central African orogenic belt during the Pan African orogeny. It consists of two greenstone belts (Zalbi and Goueygoudoum) separated by the May Kebbi calc-alkaline batholith complexes and intruded by calc-alkaline high-K granitic plutons. The whole is covered by Phanerozoic sedimentary formations. The greenstone belts contain sulphide zones hosted mainly by meta-plutonic rocks (granodiorites) and meta-basalts and meta-volcaniclastics. The mineralization comprises pyrite, pyrrhotite, arsenopyrite, chalcopyrite, pentlandite, pentlandite silver, pentlandite cobaltiferous, sphalerite, cobaltite. These sulphides are disseminated, aggregated in form of layers or are filling veins and cracks. The greenstones also contain quartz veins with calcite and chlorite comprising a mineralization made of pyrite, chalcopyrite, galena and gold. Gold is present both as native crystals and as electrum. The high-K calc-alkaline Zabili granitic pluton hosts uranium mineralization related to a superposition of: (1) ductile deformation and metasomatic alteration implying the interaction between magmatic minerals with a Na-rich fluid, of potential magmatic origin, coeval to the main deposition of uranium oxides, followed by (2) brittle deformation and deposition of secondary hydrated uranium silicates involving a Na-Ca-rich fluid. We propose that these uranium mineralizations represent the extreme expression of crustal differentiation as a result of Pan-African reworking of a Neo-proterozoic juvenile crustal segment. (author)

  14. SLH Timing Belt Powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abe


    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  15. Status report: working group on the controls of mineralization in granite-greenstone terraines of the Kaapvaal Craton

    International Nuclear Information System (INIS)

    This report summarize the activities of the working group on the controls of mineralization in Granite-Greenstone terraines of the Kaapvaal Craton. Some ore deposits in this granite-greenstone terraines have a strong affinity with those formed in modern ocean floor environments and others are associated with felsic volcanic rocks similar to those in modern island arc and Andean-type systems. Most of the deposits, however have been affected by tectonic and metamorphic processes leading to the formation of the craton. These craton forming processes have determined the present disposition of the ore bodies and have been responsible for concentrating elements such as Au and Sb into economically viable ore bodies

  16. A great thermal divergence in the mantle beginning 2.5 Ga : geochemical constraints from greenstone basalts and komatiites.


    Condie, K.C.; Aster, R.C.; J. van Hunen


    Greenstone basalts and komatiites provide a means to track both mantle composition and magma generation temperature with time. Four types of mantle are characterized from incompatible element distributions in basalts and komatiites: depleted, hydrated, enriched and mantle from which komatiites are derived. Our most important observation is the recognition for the first time of what we refer to as a Great Thermal Divergence within the mantle beginning near the end of the Archean, which we ascr...

  17. Geography of the asteroid belt (United States)

    Zellner, B. H.


    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  18. Albitization and the gold-bearing Roodepoort pluton, Pietersburg granite-greenstone terrane, South Africa

    International Nuclear Information System (INIS)

    The gold bearing Roodepoort pluton in the Pietersburg granite-greenstone terrane of South Africa consists primarily of undeformed albite with lesser amounts of quartz, ankerite, magnesite, and pyrite. The pluton intruded a major N-70 degrees trending shear zone, the Knight's Pietersburg line. The present mineralogy of the pluton and its gold content are essentially secondary, formed by open system hydrothermal alteration. However, relic minerals indicate that the pluton originally had a granodioritic composition. This composition, as well as its initial 87Sr/86Sr ratio, are similar to those of the 2 660 Ma Turfloop batholith and are consistent with the possibility that the Roodepoort pluton is an altered phase of the batholith. Sr isotopic data also suggest that hydrothermal alteration occured shortly after the magmatic crystallization of the pluton. Some alteration along the Knight's Pietersburg line occured about 2 680 Ma ago. It is proposed that the emplacement of the Roodepoort pluton, the hydrothermal alteration and the gold mineralization are related to the Limpopo Orogeny. A second phase of open system hydrothermal alteration occured in shear zones along the margins of and within the Roodepoort pluton, apparently about 2 320 Ma ago. 5 figs., 5 tabs., 27 refs

  19. Evaluation of the static belt fit provided by belt-positioning booster seats. (United States)

    Reed, Matthew P; Ebert, Sheila M; Sherwood, Christopher P; Klinich, Kathleen D; Manary, Miriam A


    Belt-positioning booster seats are recommended for children who use vehicle seat belts as primary restraints but who are too small to obtain good belt fit. Previous research has shown that belt-positioning boosters reduce injury risk, but the belt fit produced by the wide range of boosters in the US market has not previously been assessed. The present study describes the development of a method for quantifying static belt fit with a Hybrid-III 6-year-old test dummy. The measurement method was applied in a laboratory seat mockup to 31 boosters (10 in both backless and highback modes) across a range of belt geometries obtained from in-vehicle measurements. Belt fit varied widely across boosters. Backless boosters generally produced better lap belt fit than highback boosters, largely because adding the back component moved the dummy forward with respect to the lap belt routing guides. However, highback boosters produced more consistent shoulder belt fit because of the presence of belt routing guides near the shoulder. Some boosters performed well on both lap belt and shoulder belt fit. Lap belt fit in dedicated boosters was generally better than in combination restraints that also can be used with an integrated harness. Results demonstrate that certain booster design features produce better belt fit across a wide range of belt geometries. Lap belt guides that hold the belt down, rather than up, and shoulder belt guides integrated into the booster backrest provided better belt fit. PMID:19393812

  20. Chaos on the conveyor belt

    CERN Document Server

    Sándor, Bulcsú; Tél, Tamás; Néda, Zoltán


    The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by spring to an external static point, and due to the dragging effect of the belt the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can only be achieved by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic dynamics and phase transition-like behavior. Noise induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks, around five.

  1. The Glória quartz-monzodiorite: isotopic and chemical evidence of arc-related magmatism in the central part of the Paleoproterozoic Mineiro belt, Minas Gerais State, Brazil. (United States)

    Avila, Ciro A; Teixeira, Wilson; Cordani, Umberto G; Barrueto, Héctor R; Pereira, Ronaldo M; Martins, Veridiana T S; Dunyi, Liu


    The Glória quartz-monzodiorite, one of the mafic plutons of the Paleoproterozoic Mineiro belt, is intrusive into banded gneisses, amphibolites, schists and phyllites of the Rio das Mortes greenstone belt, in the southern portion of the São Francisco Craton, State of Minas Gerais, Brazil. The Glória quartz-monzodiorite yields a SHRIMP U-Pb zircon age of 2188 +/- 29 Ma, suggesting a tectonic relationship with the pre-collisional phase of the Mineiro belt. According to the Nd isotopic evidence (epsilonNd(T) = -3.4; T DM = 2.68 Ga) the original magmas was formed by a mixture among Archean crustal material and Paleoproterozoic juvenile magma. The Glória quartz-monzodiorite shows metaluminous and calc-alkaline tendency with intermediate K content, comparable to that of volcanic-arc rocks. The primary mineralogical assemblage was partly modified by metamorphism, dated between 2131-2121 Ma in nearby coeval plutons. Such metamorphism is significantly older than the reported metamorphic episodes of the Mineiro belt in the Quadrilátero Ferrífero region (2059-2041 Ma) in the eastern portion of the study area. This evidence, together with chemical and isotopic data from other mafic and felsic plutons coeval with the Glória quartz-monzodiorite, indicate a tectonic and magmatic migration within the Mineiro belt from west to east. PMID:16936942

  2. The setting of mineralization in a portion of the Eersteling goldfield, Pietersburg granite-greenstone terrane, South Africa

    International Nuclear Information System (INIS)

    Eersteling goldfield is situated in the Pietersburg granite-greenstone terrane within greenstones of the Archaean Eersteling Formation (Pietersburg Group). In the vicinity of the Eersteling Gold Mine, gold occurs in quartz-carbonate vein systems within coupled shear zones. This mineralization occurs within two settings: in east-west-trending shear zones located at lithological contacts or within discrete units (the Pienaar, Doreen, and Girlie reefs); and in Riedal shear zones between east-west trending zones (the Maltz, Dog, and unnamed reefs). In both cases, gold grades are highest within steeply plunging, structurally controlled pay shoots or boudins. Pay shoots in the Pienaar, Maltz, Dog, and an unnamed reef are characterized by the presence of pyrrhotite, chalcopyrite, and pyrite; arsenopyrite is absent or present in extremely minor amounts. Secondary calcite occurs as large crystals in extension fractures and as a finegrained infilling around clasts. Pay shoots in the Doreen and Girlie reefs are characterized by the presence of arsenopyrite and pyrite while pyrrhotite and chalcopyrite characterize low-grade zones. 28 refs., 8 figs., 4 tabs

  3. Composition and origin of fluids associated with lode gold deposits in a Mesoarchean greenstone belt (Warrawoona Syncline, Pilbara Craton, Western Australia) using synchrotron radiation X-ray fluorescence (United States)

    Thébaud, Nicolas; Philippot, Pascal; Rey, Patrice; Cauzid, Jean


    Microthermometry and Raman spectroscopy techniques are routinely use to constrain ore-fluids δ18O and molar proportions of anhydrous gas species (CO2, CH4, N2). However, these methods remain imprecise concerning the ore-fluids composition and source. Synchrotron radiation X-ray fluorescence allows access to major and trace element concentrations (Cl, Br and K, Ca, Fe, Cu, Zn, As, Rb, Sr) of single fluid inclusion. In this paper, we present the results of the combination of these routine and newly developed techniques in order to document the fluids composition and source associated with a Mesoarchaean lode gold deposit (Warrawoona Syncline, Western Australia). Fluid inclusion analyses show that quartz veins preserved records of three fluid inclusion populations. Early fluids inclusions, related to quartz veins precipitation, are characterized by a moderate to high Br/Cl ratio relative to modern seawater, CO2 ± CH4 ± N2, low to moderate salinities and significant base metal (Fe, Cu, Zn) and metalloid (As) concentrations. Late fluid inclusions trapped in secondary aqueous fluid inclusions are divided into two populations with distinct compositions. The first population consists of moderately saline aqueous brines, with a Br/Cl ratio close to modern seawater and a low concentration of base metals and metalloids. The second population is a fluid of low to moderate salinity, with a low Br/Cl ratio relative to modern seawater and significant enrichment in Fe, Zn, Sr and Rb. These three fluid inclusion populations point to three contrasting sources: (1) a carbonic fluid of mixed metamorphic and magmatic origin associated with the gold-bearing quartz precipitation; (2) a secondary aqueous fluid with seawater affinity; and (3) a surface-derived secondary aqueous fluid modified through interaction with felsic lithologies, before being flushed into the syncline. Primary carbonic fluids present similar characteristics than those ascribed to Mesoarchaean lode gold deposits. This suggests similar mineralization processes for mid- and Mesoarchaean lode gold deposits despite contrasting fluid-rock interaction histories. However, in regard to the protracted history documented in the Warrawoona Syncline, we question the robustness of the epigenetic crustal continuum model, as ore-fluid characteristics equally support an epigenetic or a polyphased mineralization process.

  4. Using the Abitibi Greenstone Belt to Understand Martian Hydrothermal Systems and the Potential for Biosignature Preservation in High Temperature Aqueous Environments (United States)

    Hurowitz, J.; Abelson, J.; Allwood, A.; Anderson, R.; Atkinson, B.; Beaty, D.; Bristow, T.; Ehlmann, B.; Eigenbrode, J.; Grotzinger, J.; Hand, K.; Halevy, I.; Knoll, A.; McCleese, D.; Milliken, R.; Russell, M.; Stolper, D.; Stolper, E.; Tosca, N.


    Metabolic bone diseases like osteoporosis result from the disruption of normal bone mineral balance (BMB) resulting in bone loss. During spaceflight astronauts lose substantial bone. Bed rest provides an analog to simulate some of the effects of spaceflight; including bone and calcium loss and provides the opportunity to evaluate new methods to monitor BMB in healthy individuals undergoing environmentally induced-bone loss. Previous research showed that natural variations in the Ca isotope ratio occur because bone formation depletes soft tissue of light Ca isotopes while bone resorption releases that isotopically light Ca back into soft tissue (Skulan et al, 2007). Using a bed rest model, we demonstrate that the Ca isotope ratio of urine shifts in a direction consistent with bone loss after just 7 days of bed rest, long before detectable changes in bone mineral density (BMD) occur. The Ca isotope variations tracks changes observed in urinary N-teleopeptide, a bone resorption biomarker. Bone specific alkaline phosphatase, a bone formation biomarker, is unchanged. The established relationship between Ca isotopes and BMB can be used to quantitatively translate the changes in the Ca isotope ratio to changes in BMD using a simple mathematical model. This model predicts that subjects lost 0.25 +/- 0.07% (+/- SD) of their bone mass from day 7 to day 30 of bed rest. Given the rapid signal observed using Ca isotope measurements and the potential to quantitatively assess bone loss; this technique is well suited to study the short-term dynamics of bone metabolism.

  5. Geochemical characteristics of gold bearing boninites and banded iron formations from Shimoga greenstone belt, India: Implications for gold genesis and hydrothermal processes in diverse tectonic settings

    Digital Repository Service at National Institute of Oceanography (India)

    Ganguly, S.; Manikyamba, C.; Saha, A.; Lingadevaru, M.; Santosh, M.; Rambabu, S.; Khelen, A.C.; Purushotham, D.; Linga, D.

    added to this mixture and thoroughly shaken for complete homogenization. Care was taken to avoid lumping of flux. The mixture was transferred to a preheated and cooled graphite crucible and kept for fusion in preheated muffle furnace at 1050± 25 °C... for one hour. Themelt obtained after fu- sion was swirled and poured into an iron mould to which a thin oil film D A B SD %RSD 88 0.002 1 3.13 0.345 71 236.975 230 0.029 0.012 11 14.094 12 0.016 0.114 03 28.517 25 0.023 0.079 12 3.187 3 0.013 0.408 86 13...

  6. Spatial Distribution of Hydrogen Production Zone and Organic Carbon; Case Study from Jurassic Ocean Plateau, the Mikabu Greenstone Belt, Central Shikoku, Japan. (United States)

    Ando, Y.; Okamoto, K.; Terabayashi, M.


    Hydrothermal activity in the Archean-Ridge system has been considered to play a major role to maintain the oldest biosphere in early Earth. In the present ridge-system, hydrogen production in the serpentinized peridotite layer, is considered as major energy source. However, low temperature hydrothermal zone in the lower crust layer in the ridge has been recognized as hydrogen producing zone. Then what is the hydrogen source in the oceanic lower crust? Accreted oceanic plateau is one of the best sample to describe hydration process due to deep-sea-hydrothermal alteration because it is easy to observe huge outcrops and collect samples systematically in whole section. We have collected rock samples from Mikabu high P/T rocks in Toba area and from Ootoyo area, Japan because there are large scale trench cliffs in the mine. Here, we report mineral composition surrounding organic carbon that was found in metabasaltic rocks from Otoyo area. The metabasalt underlies metachert, and exhibit extensive plagioclase veins. Carbonaceous material and FeS are concentrated near the veins. Serpentinization of olivine gabbro was recognized there. In the Toba area, wehrlite and hornblende gabbro are dominant as the oceanic lower crustal material, subsequently suffered high P/T metamorphism. Abundant serpentine with magnetite are along olivine grain boundaries. Cr-spinel and epidote are occasionally recognized. That is, hydrogen was produced due to hydration reaction in the intruded wherlite from the lower crust of the large plateau. In summary, the lower crust might be significant zone producing hydrogen, and provide bacteria cluster above.

  7. Middle Archaean age of Sargur group by single grain zircon dating and geochemical evidence for the clastic origin of metaquartzite from J.C. Pura greenstone belt, Karnataka

    International Nuclear Information System (INIS)

    Euhedral zircons from J.C. Pura metaquartzite were dated by single grain evaporation technique which yielded a Pb-Pb age of 3230 ± 5Ma. This date representing the maximum age of the Sargur metaquartzite is fully in accord with previous Sm-Nd model ages and SHRIMP U-Pb zircon ages (ca 3200 Ma) of Sargur rocks from nearby areas. The Sargur group is pervasively intruded by gneisses and granites around 3000 Ma. Still older gneisses seen in the neighbourhood such as the Gorur gneiss of 3300 Ma age may constitute a possible basement to the Sargur supracrustals and represent widespread early Archaean granitic crust of the Dharwar craton. (author). 45 refs., 6 tabs., 4 figs

  8. Launching jets from accretion belts

    CERN Document Server

    Schreier, Ron


    We propose that sub-Keplerian accretion belts around stars might launch jets. The sub-Keplerian inflow does not form a rotationally supported accretion disk, but it rather reaches the accreting object from a wide solid angle. The basic ingredients of the flow are a turbulent region where the accretion belt interacts with the accreting object via a shear layer, and two avoidance regions on the poles where the accretion rate is very low. A dynamo that is developed in the shear layer amplifies magnetic fields to high values. It is likely that the amplified magnetic fields form polar outflows from the avoidance regions. Our speculative belt-launched jets model has implications to a rich variety of astrophysical objects, from the removal of common envelopes to the explosion of core collapse supernovae by jittering jets.

  9. Kuiper Belts Around Nearby Stars

    CERN Document Server

    Nilsson, R; Brandeker, A; Olofsson, G; Pilbratt, G L; Risacher, C; Rodmann, J; Augereau, J -C; Bergman, P; Eiroa, C; Fridlund, M; Thébault, P; White, G J


    In order to detect and characterise cold extended circumstellar dust originating from collisions of planetesimal bodies in disks, belts, or rings at Kuiper-Belt distances (30--50\\,AU or beyond) sensitive submillimetre observations are essential. Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied. // We have performed 870\\,$\\mu$m observations of 22 exo-Kuiper-Belt candidates, as part of a Large Programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870\\,$\\mu$m fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities $f_{\\mathrm{dust}}$, dust temperatures...

  10. Magmatic origin of low-T mafic blueschist and greenstone blocks from the Franciscan mélange, San Simeon, California (United States)

    Ukar, Estibalitz; Cloos, Mark


    The Franciscan mélange exposure near San Simeon contains abundant greenstone and minor blueschist blocks that were tectonically boudinaged while encased in the shale-matrix. Tectonic deformation of the blueschists is evident from variable amounts of cataclastic flow along their margins and in pinched tails. Major, trace, and rare earth elemental analyses indicate that blueschist and greenstone blocks in this area of the mélange were derived from sources with MORB-like composition along with some having trace element and REE patterns similar to OIB compositions. Most blocks are low LREE basalts that probably formed in an open ocean ridge setting, but some blocks have high LREE contents similar to off-axis seamounts. Linear trends of incompatible elements for both blueschist and greenstone blocks indicate that both lithologies were probably derived from a similar, variably fractionated, tholeiitic magma. Blueschist blocks with sodic amphibole + lawsonite ± epidote were pervasively recrystallized at 300-350 °C and foliated during ductile deformation that included folding. Their protolith can only be identified as mafic. A few blocks contain very small amounts of metasedimentary materials indicating some were probably seafloor basalts, but some may have been diabase or even gabbro. Where interlayered sediment was present, the mafic protolith was enriched in K, Rb, and Na. Greenstones, on the other hand, contain abundant pseudomorphic evidence of magmatic textures. Alteration to albite, chlorite and pumpellyite at temperatures of 100-200 °C is intense, especially in cataclastic margins and pinched tails. Some of the basaltic greenstones have attached radiolarian chert, and a few have relict diabasic textures. The mafic blueschists and greenstones in the mélange near San Simeon are probably fragments from the uppermost part of the Farallon plate. The blueschists may be mostly mafic slabs uprooted from the subducting crust, underplated to the base of the North

  11. Origin of Archean Chromitites in the Nuggihalli Schist Belt, Dharwar Craton (India) (United States)

    Mukherjee, R.; Mondal, S. K.; Rosing, M. T.; Frei, R.


    Layered ultramafic-mafic rocks with chromitite bodies occur as sill-like intrusions within the Archean greenstone sequences of the Nuggihalli belt, Western Dharwar Craton. The 3.1Ga chromitite-bearing ultramafic-mafic rocks occur as dismembered en echelon, lenticular units that are conformable within the metasedimentary rocks, and surrounded by the tonalite-trondhjemite-granodiorite suite. The chromitite bodies are hosted within intensely deformed serpentinite, and associated with gabbro. The chromitite bodies have high length/width ratio (60-500 m/15 m) and occur in the form of pods and elongated lenses. Detailed electron microprobe study reveals high Cr/(Cr+Al)=0.85-0.86 and moderate Mg/(Mg+Fe2+)=0.38-0.58 of the primary chromite from the massive chromitite. Interstitial and included olivine and pyroxene grains within massive chromitite, exhibit very high Fo content (Fo96-98) and Mg-numbers (94-99) respectively. Chromite grains exhibit intense compositional variability due to subsolidus re-equilibration and low temperature hydrothermal alteration processes such as in the altered massive chromitite (70% chromite), serpentinite (2% chromite) and silicate-rich chromitite (45% chromite). In these associations, chromite grains are compositionally zoned and commonly altered to ferritchromit (rarely magnetite) along the rim and fractures. The primary chromite compositions are used to compute the parent melt that is characterised by low Al2O3 (8.38-10.63 wt%), moderate to high TiO2 (0.94-1.58 wt%) and FeO/MgO ratios of 0.46-0.92 wt%. The parent melt calculations indicate derivation from a high-Mg komatiitic basalt, and matches with the compositions of komatiitic rocks reported from the greenstone terrain. Parent melts are produced by high degrees of partial melting of a depleted source mantle evident from the refractory compositions of chromite, olivine and pyroxene. Tectonic discrimination diagrams indicate a supra-subduction zone setting (SSZ) for the Archean

  12. Study of thermal conditions at belt slippage

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, R.; Pampel, W.; Pfleger, P.


    Conveyor belt slippage experiments are carried out on the Chrudim (Czechoslovakia) industrial sized test stand for belt widths up to 1 m and driving drum forces up to 400 kW. The stand is operated jointly by TAKRAF (GDR) and VITKOVICE VUTZ, Prague. From 1972 to 1981, 7 belt conveyor fires occurred in GDR brown coal surface mines due to belt slippage. One of these cases led to a belt fire after only 15 s at 100% belt slippage. Aim of the study was to determine accurate permissible slippage values. Design of the test stand is explained as well as test procedures with belt slippage at the driving drum varying between 10 and 100%. Belt driving parameters were measured along with temperature of the drum surface. The heat penetration parameter b (in kJ/m/sup 2/) was calculated. Maximum temperatures up to 150 C were measured on the drum during partial slippage and 370 C at 100% belt slippage. The ignition temperature of rubber abrasion fines was also analyzed and found to vary between 40 and 318 C, i.e. substantially lower than belt and drum layer ignition temperatures. Graphs and diagram of slippage measurement results are calculated. Values for permissible maximum slippage time for operating belt slippage monitoring devices are shown. These devices are required to be installed in the GDR at heavy mine belt conveyors with driving forces exceeding 500 kW. 8 refs.

  13. French experience in seat belt use.

    NARCIS (Netherlands)

    Lassarre, S. & Page, Y.


    This paper concerns the French experience in seat belt use. As well as the seat belt regulations, the strategies employed to reinforce the wearing of seat belts by using information and encouragement campaigns and checks by the police and gendarmerie are described here along with their timetables an

  14. Ocorrência de rochas da fácies granulito no Cinturão Mineiro, Minas Gerais, Brasil Occurrence of granulite-facies rocks in the Mineiro Belt, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Newton Souza Gomes


    Full Text Available Na região de Lagoa Dourada, inserida no Cinturão Mineiro, ocorrem granitóides paleoproterozóicos, que intrudem seqüências supracrustais arqueanas do greenstone belt Rio das Velhas. Os granitóides são cortados por rochas máficas anfibolitizadas, que portam xenólitos de granulitos. Trata-se de granulitos máficos caracterizados pela textura granoblástica e pela paragênese ortopiroxênio-clinopiroxênio-anfibólio-plagioclásio. Como fases secundárias, registram-se actinolita, cummingtonita, carbonato, epídoto, granada e quartzo. Determinações geotermométricas baseadas nos pares minerais ortopiroxênio-clinopiroxênio e anfibólio-plagioclásio produziram valores de temperatura entre 700 e 853ºC. As fases secundárias são produtos de um processo metamórfi co posterior.Paleoproterozoic granitoids intruding the Archean greenstone belt of Rio das Velhas are found in the region of Lagoa Dourada, which belongs to the Mineiro Belt. The granitoids are cut by amphibolitized mafi c rocks which contain xenoliths of granulite facies rocks. The rocks are mafi c granulites, characterized by their granoblastic texture and by parageneses orthopyroxene-clinopyroxene-amphibole-plagioclase. As secondary minerals, actinolite, carbonate, epidote, cummingtonite, garnet and quartz can be found. Geothermometric determinations based on the mineral pairs orthopyroxene-clinopyroxene and amphibole-plagioclase yielded temperature values between 700ºC and 853ºC. The secondary mineral phases are interpreted as a result of a younger metamorphic event.

  15. Ordination and classification of vegetation of Songimvelo Game Reserve in the Barberton Mountainland, South Africa for the assess­ ment of wildlife habitat distribution and quality

    Directory of Open Access Journals (Sweden)

    M. Stalmans


    Full Text Available A vegetation survey was undertaken of the 49 000 ha Songimvelo Game Reserve in the Barberton Mountainland of Mpumalanga. South Africa with the aim to identify constituent plant communities and to assess their relative value to wild herbivores. The vegetation is highly diverse with representation of three biomes: Savanna. Grassland and Forest A total of 428 plots were sampled by means of a semi-quantitative technique. Data were subjected to ordination (CANOCO and clas­sification (PATN. The composition of the 19 distinct communities is determined through an intricate combination of environmental factors as evident from the ordination results. Firstly drainage line' position is critical, followed by land use history and further by the interplay between elevation and geology. These findings are in line with results obtained from other studies along the eastern Escarpment. Alluvium, mafic and ultramafic lavas support mixed veld, whereas felsic lavas, sandstones and quartzites support sour veld which has a very low forage value in the dry’ season. Each community, through its specific species assemblage, structure and location, forms a distinctly different habitat in terms of its value to the various species of herbivores in the SGR

  16. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Dean, J.; Acosta, J.


    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  17. Belt technology stretches conveyors' coverage

    Energy Technology Data Exchange (ETDEWEB)



    With China the leading growth engine in the conveyor market, leading belt manufacturers are establishing local manufacturing plants to boost their presence. Fenner is planning to almost triple production capacity over the next three years, with a third of its investment in China. Shanxi-Phoenix Conveyor Belt Systems is a joint venture between Phoenix Conveyor Belt Systems GmbH, now part of ContiTech Ag, and its Chinese partners Lu An Mining Group Co. Ltd. and Jingcheng Anthracite Group Co. Ltd. It manufacturers steel cable belts, PVC and multi-ply belts for coal mines and power plants. Recent belt designs by FennerEurope and Metso Minerals are reported. 2 photos.


    Institute of Scientific and Technical Information of China (English)

    Li Yinghui; Gao Qing; Jian Kailin; Yin Xuegang


    The nonlinear dynamic responses of viscoelastic axially transmission belts are investigated and the Kelvin viscoelastic differential constitutive model is employed to characterize the material property of belts. The generalized equation of motion is obtained for a viscoelatic axially transmission belts with geometric nonlinearity first, and then is reduced to be a set of second-order nonlinear ordinary differential equations by applying Galerkin's method. Finally, the effects of viscosity parameter and elastic parameter and the moving velocity of the belts on the transient responses are investigated by the research of digital simulation.

  19. Brusque belt: a monocyclic evolution ?

    International Nuclear Information System (INIS)

    This paper discusses the radiometric data for the Brusque Belt (SC) where Rb-Sr isochrons, U-Pb in zircons, K-Ar in minerals and whole rock Sm-Nd model ages are available. The analysis of these results reveals two main groups, without intermediate values. The first, 500 to 800Ma., is related to magmatic and metamorphic ages and the second, 1600-2000Ma begin with the (probably) sedimentation age. A monociclic evolution is proposed, but with uncertanties in the age of the first metamorphic phase. (author)

  20. The Wisconsin magmatic terrane: An Early Proterozoic greenstone-granite terrane formed by plate tectonic processes (United States)

    Schulz, K. J.; Laberge, G. L.


    The Wisconsin magmatic terrane (WMT) is an east trending belt of dominantly volcanic-plutonic complexes of Early Proterozoic age (approx. 1850 m.y.) that lies to the south of the Archean rocks and Early Proterozoic epicratonic sequence (Marquette Range Supergroup) in Michigan. It is separated from the epicratonic Marquette Range Supergroup by the high-angle Niagara fault, is bounded on the south, in central Wisconsin, by Archean gneisses, is truncated on the west by rocks of the Midcontinent rift system, and is intruded on the east by the post-orogenic Wolf river batholith. The overall lithologic, geochemical, metallogenic, metamorphic, and deformational characteristics of the WMT are similar to those observed in recent volcanic arc terranes formed at sites of plate convergence. It is concluded that the WMT represents an evolved oceanic island-arc terrane accreated to the Superior craton in the Early Proterozoic. This conclusion is strengthened by the apparent absence of Archean basement from most of the WMT, and the recent recognition of the passive margin character of the epicratonic Marquette Range Supergroup.

  1. Qingyuan high-grade granite-greenstone terrain in the Eastern North China Craton: Root of a Neoarchaean arc (United States)

    Peng, Peng; Wang, Chong; Wang, Xinping; Yang, Shuyan


    The Qingyuan high-grade granite-greenstone terrain is one of the first recognized granite-greenstone terrains in the Eastern North China Craton. Similar to other Archaean terrains, its tectonic environment is debated: was it an intra-continental rift or a modern analogy of arc? Occurrence and petrogenesis of major igneous series, the ultramafic-mafic and felsic volcanic rocks (> 2510 Ma) and the plutons of the quartz diorite (2570-2510 Ma), TTG (2570-2510 Ma) and quartz monzodiorite (2510-2490 Ma) series in Xinbin area are investigated. The mafic intrusives and volcanic rocks have high MgO content (5.4-7.5 wt.%) and Mg-number (48-61). They show slightly depleted to flat trace element patterns. The ultramafic rocks (serpentinite) could be genetically related to the mafic rocks. The meta-dacite-rhyolite is adakitic with enriched light and middle REEs and LILEs, but significantly depleted HFSEs. The quartz diorite has high Mg-number (60-64), moderately enriched light and middle REEs and LILEs. The TTG shows distinct light but moderate middle REE-enrichment, prominent Nb-Ta-depletion but Zr-Hf-enrichment (Zr/Sm > 100). The quartz monzodiorite has moderate light and middle REE-enrichment, significant Nb-Ta-depletion, and negative Eu-/Sr-anomalies. The TTG has more depleted Sr-Nd isotopes (εNdt = + 2-+ 6; 87Sr/86Srt = ~ 0.700) than all the others (εNdt = 0-+ 2; 87Sr/86Srt = 0.701-703). Their petrogenesis can be explained by an Archaean-style subduction defined as a mantle wedge-absent flat-'hot'-subduction with significant vertical tectonism in the overriding slab: the ultramafic-mafic rocks were originated from primitive mantle; the meta-dacite-rhyolite was originated from the eclogite facies overriding crust; the quartz diorite was a mixture of melts from mantle and the overriding crust; the TTG was from the subducting slab under amphibolite to amphibole-bearing eclogite facies; and the quartz monzodiorite was from the subducting slab after the derivation of the TTG

  2. Apparatus for heat treating plastic belts (United States)

    Topits, A., Jr.


    Apparatus performs programed rotating, stretching/shrinking and heat treatment necessary to fabrication of high-performance plastic belts. Belts can be treated in lengths varying from 7 to 48 in., in widths up to 1 in., and in thicknesses up to approximately 0.003 in.

  3. Parameters affecting seat belt use in Greece. (United States)

    Yannis, G; Laiou, A; Vardaki, S; Papadimitriou, E; Dragomanovits, A; Kanellaidis, G


    The objective of this research is the exploration of seat belt use in Greece and particularly the identification of the parameters affecting seat belt use in Greece. A national field survey was conducted for the analytical recording of seat belt use. A binary logistic regression model was developed, and the impact of each parameter on seat belt use in Greece was quantified. Parameters included in the model concern characteristics of car occupants (gender, age and position in the car), the type of the car and the type of the road network. The data collection revealed that in Greece, the non-use of seat belt on the urban road network was higher than on the national and rural road network and young and older men use seat belts the least. The developed model showed that travelling on a national road is negative for not wearing the seat belt. Finally, the variable with the highest impact on not wearing a seat belt is being a passenger on the back seats. PMID:21452095

  4. Understanding Quaternions and the Dirac Belt Trick (United States)

    Staley, Mark


    The Dirac belt trick is often employed in physics classrooms to show that a 2n rotation is not topologically equivalent to the absence of rotation whereas a 4n rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors…

  5. Situational characteristics of safety belt use. (United States)

    Fockler, S K; Cooper, P J


    Past research concerning the use and nonuse of safety belts has tended to stereotype users and nonusers as distinct entities on the basis of a single observed situation. The thought processes underlying the reasons given by drivers for using or not using seat belts have not been explored. The purpose of this study was to observe belt use by a group of drivers and describe factors contributing to their use or nonuse as defined by the drivers themselves. In-depth interviews were undertaken with 239 drivers whose safety belt wearing behavior was observed in specific city or highway driving locations. Vehicle license numbers, gender, and age group of selected drivers were used to retrieve driver records and insurance policy data. Open-ended questions were asked concerning their reasons for use or nonuse and their attitudes towards safety belts and other types of traffic safety countermeasures. Driver attitudes, characteristics, and records were compared between observed safety belt user and nonuser groups to validate variables predicting use or nonuse. Respondents' descriptions of the social and personal context of their choice to use or not use safety belts provide a broader view of seat belt wearing that suggests implications for planning future enforcement and education programs. PMID:2331287

  6. The Gould's Belt distance survey

    CERN Document Server

    Loinard, L; Torres, R M; Dzib, S; Rodriguez, L F; Boden, A F


    Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object within 500 pc of the Sun to better than a few percent. Because they are magnetically active, young stars are often associated with compact radio emission detectable using VLBI techniques. Here we will show how VLBI observations have already constrained the distance to the most often studied nearby regions of star-formation (Taurus, Ophiuchus, Orion, etc.) and have started to provide information on their internal structure and kinematics. We will then briefly describe a large project (called The Gould's Belt Distance Survey) designed to provide a detailed view of star-formation in the Solar neighborhood using VLBI observations.

  7. Strategy for replacing conveyor belts in complex haulage systems

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, L.; Jurdziak, L.; Masella, J.


    Discusses service life and reliability of conveyor belts used for mine haulage in brown coal surface mining and a method for optimizing belt service life. Based on analysis of operation of 900-1,200 m long belt conveyors in the Konin surface mine, failure rates and factors that influence belt reliability were determined. Effects of joints, length of belt sections and service life of each belt section were analyzed. Formulae for determining the optimum time interval for replacing belt sections on a long belt conveyor were derived. The formulae consider cost of new belt sections, replacement cost and haulage losses associated with possible belt failure caused by excessive belt service life. The optimization procedure has been successfully tested at the Turow surface mine and power plant. 4 refs.

  8. Southern Brasilia Belt (SE Brazil): tectonic discontinuities, K-Ar data and evolution during the Neoproterozoic Brasiliano orogeny

    International Nuclear Information System (INIS)

    This paper focuses the tectonic evolution of the southern brasilia belt, with emphasis on the Furnas segment, along the 21 deg C S parallel. The uppermost structural unit (Passos Nappe - PN) comprises a highly deformed metasedimentary succession interpreted as a fragment of the Neoproterozoic passive margin of western Sao francisco craton. An inverted metamorphic gradient ranging from greensvhits to lower granulite facies of medium to high-pressure regime characterizes the PN as relict of a subduction zone. The External Domain display a complex imbrication of basement rocks (Archean Piumhi greenstones, a turbiditic gaywacke succession and a calc-alkaline granitoid suite) with undated siliciclast low-grade metasedimentary rocks. The Sao Francisco Craton (SFC) comprises pre-1.8 Ga basement rocks covered by anchimetamorphic Neoproterozoic carbonatic shallow marine platform deposits of the Bambui group. The Brasiliano thrust stacking generated a coarse clastic influx of molassic character on the foreland zone of Sao Francisco Craton, coeval with the exhumation of the External Domain thrust sheets. New K-Ar determinations on mineral separates are presented an interpreted among previous data. The SFC basement rocks display Paleo-to Meesoproterozoic cooling ages. The allochthonous units, in contrast, display K-Ar ages within the 560-675 Ma range. Brasiliano thrust stacking is therefore interpreted to have taken place onto a cold Sao Francisco craton foreland, in a thin-skinned style, as basement rocks were not heated enough to have their-K-ar systems reset during the allochthony. (author)

  9. Seat belt use law in developing countries

    Institute of Scientific and Technical Information of China (English)



    Objective:To highlight the way to successful implementation of mandantory seat belt use law in developing countries particulary where have significant increase in number or cars and subsequent increase in car occupant casualties.Methods:Literatures concerning seat belt use were reviewed and experiences of the world.Satisfactory or not,investigated.It summed up general aspects of seat belt use as well as benefits,attitude toward legislation and measures to enhance the usage.Results:Seat belt use has been proven and stood time tested as the most effective means to protect car occupants from road crash injuries.It appears to be arduous to achieve the golal of seat belt use law in developing countries. but possible via strategies appropriately leading to legislation and promotion of the belt usage.Conclusions:It is prime necessity for the government authorities to recognize the importance of seat belt use.There needs an organizational structure composed of relevant professional from both private and government sectors which is able to carry out every steps toward successful legislation and implementation:education,publicity,enforcement,evaluation and dissemination of the law's benefits.


    Institute of Scientific and Technical Information of China (English)

    李映辉; 高庆; 蹇开林; 殷学纲


    Based on the Kelvin viscoelastic differential constitutive law and the motion equation of the axially moving belt, the nonlinear dynamic model of the viscoelastic axial moving belt was established. And then it was reduced to be a linear differential system which the analytical solutions with a constant transport velocity and with a harmonically varying transport velocity were obtained by applying Lie group transformations. According to the nonlinear dynamic model, the effects of material parameters and the steady-state velocity and the perturbed axial velocity of the belt on the dynamic responses of the belts were investigated by the research of digital simulation. The result shows: 1 ) The nonlinear vibration frequency of the belt will become small when the relocity of the belt increases. 2 ) Increasing the value of viscosity or decreasing the value of elasticity leads to a deceasing in vibration frequencies. 3 ) The most effects of the transverse amplitudes come from the frequency of the perturbed velocity when the belt moves with harmonic velocity.

  11. From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives: influence of tensioner and belt characteristics


    Manin, Lionel; Michon, Guilhem; Rémond, Didier; Dufour, Regis


    Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip: dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been u...

  12. Petrology and structure of greenstone blocks encased in mud-matrix melange of the Franciscan complex near San Simeon, California

    Energy Technology Data Exchange (ETDEWEB)

    Davidsen, R.K.; Cloos, M.


    Greenstones comprise about 20% of all mappable (>1 m) blocks encased in blueschist-block-bearing mud-matrix melange exposed in a 10 km-length of sea cliffs near San Simeon. Field and petrographic analysis of 25 blocks show they vary from finely crystalline (<1 mm) locally porphyritic or amygdaloidal, volcanics to coarsely crystalline (1 to 5 mm) diabase. Some are in contact with bedded chert and two have relict pillows. However, most blocks are intensely deformed. Pinch-and-swell and boundinage are recognized on scales from cm to about 10 m. Distortion was accommodated by cataclasis to an aggregate of pieces from mm to m across. Generally, m-sized blocks are pervasively cataclastic whereas larger blocks are crosscut by cataclastic zones that emanate from pervasively cataclastic margins or necked regions of boudins. Discontinuous, cm-thick veins and cavities that are lined by quartz and clacite and rarely, laumontite, prehnite and aragonite locally crosscut all other structures. Relict igneous textures show the primary minerals are plagioclase and clinopyroxene. Abundant secondary minerals, particularly in cataclastic zones, are albite, chlorite, pumpellyite (some have high Al), and calcite. The metamorphic parageneses indicate relatively minor greenschist-facies, sea-floor-type alterations under static conditions followed by lower-temperature alterations synchronous with cataclasis and the development of boudinage. If the blocks are fragments of disrupted ophiolites, only the uppermost section of the suite are present within the mud-matrix melange near San Simeon. The simplest explanation for their crystallization, metamorphism and incorporation into the melange is that they are fragments of seamounts dismembered during subduction.

  13. Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, T. [Mazda Motor Corp., Hiroshima (Japan)


    V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

  14. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P


    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  15. Handbook Timing Belts Principles, Calculations, Applications

    CERN Document Server

    Perneder, Raimund


    Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

  16. Dynamics of the outer asteroid belt

    International Nuclear Information System (INIS)

    This paper considers the issue of modeling the dynamics of the outer asteroid belt. The hypotheses and assumptions of an asteroid-belt model are discussed together with their problems, of which gaps at some mean-motion resonances with Jupiter and the depletion of the outer belt are the most outstanding ones. Particular attention is given to the theory of the 2:1 gap, the depletion problem, and the mechanisms of dynamical protection against strong perturbations by Jupiter. It is suggested that the observed asteroids must have gone through a process of natural selection as a result of which all objects in unprotected orbits have been ejected from the system. Spectral observations show a reddening in spectral slope with increasing heliocentric distance; it is proposed that this is an evidence that outer-belt asteroids might be primordial objects. 41 refs


    Directory of Open Access Journals (Sweden)

    L. Loinard


    Full Text Available Observaciones que utilizan la interferometría de muy larga línea de base (VLBI por sus siglas en ingl´es pueden proveer la posición de radiofuentes compactas con una precisión del orden de 50 micro-segundos de arco. Esto es suficiente para medir la paralaje trigonométrica y los movimientos propios de cualquier objeto localizado hasta 500 pc del Sol con una precisión mejor que unos porcientos. Por ser magnéticamente activas, las estrellas jóvenes a menudo emiten emisión radio compacta detectable usando técnicas VLBI. Aquí, mostraremos cómo observaciones VLBI ya han restringido la distancia a las regiones de formación estelar cercanas más frecuentemente estudiadas (Tauro, Ofiuco, Orión, etc. y han empezado a revelar su estructura y su cinemática interna. Luego, describiremos un gran proyecto (llamado The Gould's Belt Distance Survey diseñado para proveer una vista detallada de la formación estelar en la vecindad Solar, usando observaciones VLBI.

  18. Seat belts, airbags and child protection devices. [previously: Seat belts and child restraint seats.

    NARCIS (Netherlands)


    In the Netherlands, the use of seat belts results in a yearly reduction of hundreds of fatalities. Seat belts reduce the risk of fatal injury by 37 to 48%, depending on the position in the car. At 50%, the effect of child protection devices is even slightly higher. When last measured (in 2010), 97%

  19. Analysis of stress distribution of timing belts by FEM; Yugen yosoho ni yoru timing belt oryoku kaiseki (belt code oryoku bunpu kaiseki hokoku)

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Y.; Tomono, K.; Takahashi, H.; Uchida, T. [Honda R and D Co. Ltd., Tokyo (Japan)


    A model of the belt analyzed by-ABAQUS (: a general nonlinear finite element program) successfully confirmed the mechanism that generates the belt cord stress. A quite good agreement between experimental and computed results for the stress distribution of the belt cord. It is found that maximum stress of the cords occurs near the root of the tooth by calculation, where the belt cords break off. 3 refs., 9 figs.

  20. The Compositions of Kuiper Belt Objects

    CERN Document Server

    Brown, Michael E


    Objects in the Kuiper belt are small and far away thus difficult to study in detail even with the best telescopes available at earth. For much of the early history of the Kuiper belt, studies of the compositions of these objects were relegated to collections of moderate quality spectral and photometric data that remained difficult to interpret. Much early effort was put into simple correlations of surface colors and identifications of spectral features, but it was difficult to connect the observations to a larger understanding of the region. The last decade, however, has seen a blossoming in our understanding of the compositions of objects in the Kuiper belt. This blossoming is a product of the discoveries of larger -- and thus easier to study -- objects, continued dedication to the collection of a now quite large collection of high quality photometric and spectroscopic observations, and continued work at the laboratory and theoretical level. Today we now know of many processes which affect the surface compos...

  1. Lubricants for Metal Belt Continuously Variable Transmissions

    Directory of Open Access Journals (Sweden)

    Keiichi Narita


    Full Text Available This paper reviews the effects of lubricant additives and base stock used in metal belt continuously variable transmissions (CVT fluids on the CVT transmission torque capacity. Additive formulation composed of phosphorus anti-wear agent, calcium detergent, and dispersant improved the friction coefficient between the metals. The analysis on the post-test surface suggests that the friction behavior strongly depends on the local morphology of the tribofilms derived from lubricant additives. Examining the effect of base stock on the torque capacity in actual belt CVTs revealed that SN (synthetic naphthene exhibited 10% higher torque capacity than that of PAO (polyalphaolefin. It is believed that the difference in the torque capacity is due to the difference in the oil-film shearing force generated by the relative sliding between the belt and pulley.

  2. A shell model for tyre belt vibrations (United States)

    Lecomte, C.; Graham, W. R.; Dale, M.


    We present a new formulation for the prediction of tyre belt vibrations in the frequency range 0-500 Hz. Our representation includes the effects of belt width, curvature and anisotropy, and also explicitly models the tyre sidewalls. Many of the associated numerical parameters are fixed by physical considerations; the remainder require empirical input. A systematic and general approach to this problem is developed, and illustrated for the specific example of a Goodyear Wrangler tyre. The resulting predictions for the radial response to radial forcing show good correspondence with experiment up to 300 Hz, and satisfactory agreement up to 1 kHz.

  3. Timing belts - development, milestones and innovations; Zahnriemen Entwicklungsmeilensteine und Innovationen

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, H. [Contitech Power Transmission Group (Germany)


    Contitech has much contributed to improve the characteristics of timing belts until today. In this article Contitech introduces some current developments and shows the advantages of belts compared to chain drives. (orig.)

  4. Composite Microdiscs with a Magnetic Belt

    DEFF Research Database (Denmark)

    Knaapila, Matti; Høyer, Henrik; Helgesen, Geir


    We describe an emulsion-based preparation of patchy composite particles (diameter of 100-500 mu m) consisting of a disclike epoxy core and a belt of porous polystyrene particles (diameter of 30 mu m) with magnetite within the pores. Compared to the magnetically uniform polystyrene particles, the...

  5. Isotopic and trace element studies of the origin emplacement and deformation of Archaen mineral deposits in the granite-greenstone terrains of the Kaapvaal Craton

    International Nuclear Information System (INIS)

    The granite-greenstone terrains of the Kaapvaal Craton contain among the oldest metamorphic rocks recognized on Earth and also contain a geographically disproportionately large abundance of mineral concentrations (in particular Au and Sb). However, very little is known about these occurrences a far as the source and age of the rocks in which they occur, the age of the mineralization, the nature and ages of the deformational events affecting the host rocks and the mineralization, the source of the mineralization (in particular Au, Sb and Cu), the mode of concentration of the mineralization, the behaviour of the occurrences in response to metamorphism, why some rocks are mineralized and other compositionally similar rocks are not, and whether or not the occurrences are temporally unique in terms of Earth history, i.e. are they only typical of the Archaean before 3500 Ma ago The objectives of this project were to study these eight aspects

  6. Imaging Jupiter Radiation Belts At Low Frequencies (United States)

    Girard, J. N.; de Pater, I.; Zarka, P.; Santos-Costa, D.; Sault, R.; Hess, S.; Cecconi, B.; Fender, R.; Pewg, Lofar


    The ultra-relativistic electrons, trapped in the inner radiation belts of Jupiter, generates a strong synchrotron radio emission (historically known as the jovian decimeter radiation (DIM)) which is beamed, polarized (~20% linear, ~1% circular) and broadband. It has been extensively observed by radio telescopes/ probes and imaged by radio interferometers over a wide frequency spectrum (from >300 MHz up to 22 GHz). This extended emission presents two main emission peaks constantly located on both sides of the planet close to the magnetic plane. High latitude emissions were also regularly observed at particular frequencies, times and in particular observational configurations. This region of the magnetosphere is "frozen" due to the strong magnetic field (~4.2 G as the equator) and therefore is forced to rotate at the planetary period (T≈9h55m). Due to the tilt (~ 10o) between the spin axis of the planet and the magnetic axis (which can be seen as dipolar in first approximation), the belts and the associated radio emission wobble around the planet center. The analysis of the flux at different frequencies highlighted spatial, temporal and spectral variabilities which origins are now partly understood. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility effect (wobbling, beaming, position of the observer in the magnetic rotating reference frame) [1], [2] and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) [3], [4], [5]. A complete framework is necessary to fully understand the source, loss and transport processes of the electrons originating from outside the belt, migrating by inward diffusion and populating the inner region of the magnetosphere. Only a few and unresolved measurements were made below 300 MHz and the nonsystematic observation of this radio emission

  7. Detecting Extrasolar Asteroid Belts Through Their Microlensing Signatures

    CERN Document Server

    Lake, Ethan; Dong, Subo


    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called "pseudo-caustics", regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive microlensing light curves across a wide region of belt parameter space and possess remarkably large lensing cross-sections. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys (e.g., WFIRST) may be able to discover extrasolar asteroid belts with masses of the order of $0.1 M_{\\oplus}$.

  8. Seat Belt Use Among Adult Workers - 21 States, 2013. (United States)

    Boal, Winifred L; Li, Jia; Rodriguez-Acosta, Rosa L


    Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use. PMID:27309488


    Institute of Scientific and Technical Information of China (English)

    薛河; 苏清祖; 马胜利


    The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are'systematically analyzed and some computing formulas derived, by these formulas, the actual load distribution onthe two drums of rigid connected or separately driving belt conveyor can be separately calculated. These formulas also can be as the theory base for adjusting the driving force of two drums.

  10. Ionic composition of the earth's radiation belts (United States)

    Spjeldvik, W. N.


    Several different ion species have been positively identified in the earth's radiation belts. Besides protons, there are substantial fluxes of helium, carbon and oxygen ions, and there are measurable quantities of even heavier ions. European, American and Soviet space experimenters have reported ion composition measurements over wide ranges of energies: at tens of keV (ring-current energies) and below, and at hundreds of keV and above. There is still a gap in the energy coverage from several tens to several hundreds of keV where little observational data are available. In this review emphasis is placed on the radiation belt ionic structure above 100 keV. Both quiet time conditions and geomagnetic storm periods are considered, and comparison of the available space observations is made with theoretical analysis of geomagnetically trapped ion spatial, energy and charge state distributions.

  11. A belted kingfisher flies above KSC (United States)


    A belted kingfisher soars over the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The pigeon-sized, blue-gray male is identified by the blue-gray breast band; females show a chestnut belly band. The belted kingfisher ranges throughout the United States and Canada, wintering south to Panama and the West Indies. They dive into the water for fish and may also take crabs, crayfish, salamanders, lizards, mice and insects. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  12. Alien Asteroid Belt Compared to our Own (United States)


    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  13. Understanding quaternions and the Dirac belt trick

    International Nuclear Information System (INIS)

    The Dirac belt trick is often employed in physics classrooms to show that a 2π rotation is not topologically equivalent to the absence of rotation whereas a 4π rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors has been achieved, or if the trick is just an amusing analogy. The goal of this paper is to demystify the belt trick and to show that it suggests an underlying four-dimensional parameter space for rotations that is simply connected. An investigation into the geometry of this four-dimensional space leads directly to the system of quaternions, and to an interpretation of three-dimensional vectors as the generators of rotations in this larger four-dimensional world. The paper also shows why quaternions are the natural extension of complex numbers to four dimensions. The level of the paper is suitable for undergraduate students of physics.

  14. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger


    Full Text Available High altitude nuclear explosions (HANEs and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR. Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  15. Substyles of belting: phonatory and resonatory characteristics. (United States)

    Sundberg, Johan; Thalén, Margareta; Popeil, Lisa


    Belting has been described as speechlike, yell-like, or shouting voice production commonly used in contemporary commercial music genres and substantially differing from the esthetic of the Western classical voice tradition. This investigation attempts to describe phonation and resonance characteristics of different substyles of belting (heavy, brassy, ringy, nasal, and speechlike) and the classical style. A professional singer and voice teacher, skilled in these genres, served as the single subject. The recorded material was found representative according to a classification test performed by an expert panel. Subglottal pressure was measured as the oral pressure during the occlusion for the consonant /p/. The voice source and formant frequencies were analyzed by inverse filtering the audio signal. The subglottal pressure and measured flow glottogram parameters differed clearly between the styles heavy and classical assuming opposite extremes in most parameters. The formant frequencies, by contrast, showed fewer less systematic differences between the substyles but were clearly separated from the classical style with regard to the first formant. Thus, the differences between the belting substyles mainly concerned the voice source. PMID:21439776

  16. Araguaia fold belt, new geochronological data

    International Nuclear Information System (INIS)

    The northern part of the Araguaia Fold Belt (AFB) outcrops in a N-S direction for about 400 km in the state of Tocantins. Dome-like structures occur in this fold belt also in a N-S direction. Both deformation and metamorphism increase from the West to the East. The basement of the AFB consist of Colmeia complex and Cantao gneiss, which crop out mainly in the core of the dome-like structures. The supracrustals rocks of the fold belt belongs to the Baixo Araguaia supergroup which is divided into the lower Estrondo group and the upper Tocantins group. Preliminary Sm-Nd data from the Colmeia complex (Grota Rica dome) gave Archean model ages of 2.8 Ga (TNd sub(DM)) while Rb-Sr data in the same rocks give an age of 2530 ± 200 Ma. In the others dome-like structures, the Rb-Sr systematics gave ages for the Colmeia a complex of 2239 ± 47 Ma (Colmeia structure) and 1972 ± 46 Ma (Lontra structure). These younger ages are believed to represent partial to total isotopic resetting of the Rb-Sr system during the Transamazonian Event. The Rb-Sr studies of the Cantao gneiss gave an age of 1774 ± 31 Ma. (author)

  17. Seat belt use during pregnancy in Iran: attitudes and practices

    Institute of Scientific and Technical Information of China (English)

    Mojgan Karbakhsh; Zahra Ershadi; Ali Khaji; Fatemeh Rahimi-Sharbaf


    Objective: Seat belt use during pregnancy reduces injury to the mother and her fetus. During recent years, the use of seat belts has been mandated by law in Iran. The purpose of this study was to determine the attitudes and practices of pregnant women regarding seat belt use.Methods: In this cross-sectional study, we asked 335 pregnant women at a hospital-based prenatal care clinic on the use of safety belt before and during pregnancy. SPSS version 13.0 was used for data analysis.Results: The mean age of study subjects was 27.3 years±5.3 years with the median of 27 years. Compared with the seat belt use before pregnancy, no change was detected in 48.7% of the women; seat belt use had increased in 17.5 %of them and decreased in 33.8 %. Eighty-one percent of women knew the correct placing of both lap belt and shoulder belt. Only 4% of women had received education on proper restraint use during pregnancy.Conclusions: The prevalence of seat belt use during pregnancy is lower than reports which are mostly from developed nations. The fact that about one-third of women have decreased their seat belt usage during pregnancy highlights the importance of education of mothers on this topic.

  18. Geochemistry of the Halogens (I, Br, Cl) and Evolution of the Seawater During the Archean (United States)

    Avice, G.; Marty, B.; Burgess, R.; Goldsmith, S. L.


    Halogens (I, Cl, Br) on Earth are depleted relative to the results of the condensation sequence of elements from the solar nebula [1]. The cause of this depletion remains unknown but might be related to loss from impacts or to the presence of an hidden reservoir (e.g. core). The presence of fluid inclusions in hydrothermal quartz of various ages is an opportunity to follow the evolution of the composition of the atmosphere (N, noble gases) through time [2] but also of halogens in seawater (their main reservoir). Such studies may help to constrain what is the origin of these volatile elements on Earth. For this purpose, we analysed quartz from hydrothermal veins and pods of various localities and ages (e.g. Barberton Greenstone Belt (South Africa; 3.2 Ga), Fortescue Group (Australia; 2.7 Ga)) by crushing and step-heating following the extended Ar-Ar method [3]. In Barberton and Fortescue Gp. quartz, a hydrothermal component characterized by excess 40Ar (40ArE) and closely associated with chlorine is clearly identified from crushing and step-heating results and permits to define a 40ArE/Cl used to correct Ar-Ar data for this contribution. In the case of Barberton, the correction for the hydrothermal component leads to an approximate formation age of the quartz of 3.2 (+/- 0.1) Ga. In Barberton quartz, halogens elemental ratios obtained during crushing and step-heating experiments are highly enriched in iodine and bromine (I/Cl=2-7x10-4; Br/Cl=4-10x10-3) relative to modern seawater. These results are similar to those found in a previous study of Barberton fluid inclusions [3] and can be interpreted as indicators that organic carbon was not sufficiently abundant at this time and/or this location to efficiently pump Br and I during sediment burial. Iodine and bromine, in Fortescue Gp. quartz, are less enriched suggesting that, in that case, organic activity already acted as pump for these elements. [1] Sharp & Draper (2013) EPSL, 369-370, p. 71-77 [2] Pujol et al. (2011

  19. Metamorphic fluid flow in the northeastern part of the 3.8-3.7 Ga Isua Greenstone Belt (SW Greenland): A re-evalution of fluid inclusion evidence for early Archean seafloor-hydrothermal systems

    DEFF Research Database (Denmark)

    Heijlen, Wouter; Appel, P. W. U.; Frezzotti, M. L.;


    density (ranging from 48.0 to > 105.3 cm(3)/Mol) and metastable H2O NaCl(-other salt?) brines (similar to 28 eq. wt% NaCl). Finally, the youngest fluid inclusion assemblages are found in non-luminescent secondary quartz and contain low-density CH4 (molar volume > 105.33 cm(3)/Mol) and low-salinity H2O-NaCl......-rich (+H2O, +graphite) and brine-rich (+CO2, +halite, +carbonate) inclusions. The gas-rich inclusions have molar volumes between 44.8 and 47.5 cm(3)/Mol, while the brine inclusions have a salinity of similar to 33 eq. wt% NaCl. Modeling equilibrium immiscibility using volumetric and compositional...... (0.2-3.7 eq. wt% NaCl.) These successive fluid inclusion assemblages record a retrograde P-T evolution close to a geothermal gradient of similar to 30 degrees C/km, but also indicate fluid pressure variations and the introduction of highly reducing fluids at similar to 200-300 degrees C and 0...

  20. Stratigraphy and U-Pb zircon geochronology of Kidd Creek: implications for the formation of giant volcanogenic massive sulphide deposits and the tectonic history of the Abitibi greenstone belt

    International Nuclear Information System (INIS)

    Within the context of a structural-stratigraphic analysis of the giant Kidd Creek Cu-Zn-Ag deposit, precise U-Pb zircon ages have been obtained for five critical rock units associated with the deposit. Massive, flow-banded footwall rhyolite is dated at 2714.3 ± 1.2 Ma, slightly younger than a previously published age of 2717 ± 2 Ma on nearby rhyolite breccia. Extrusive rhyolite in the immediate hanging wall to the main ore lenses is dated at 2711.5 ± 1.2 Ma, leaving an interval of one to several million years for the formation of the deposit. We consider the demonstrated longevity of the Kidd Creek hydrothermal system as a major control on its giant size. Age constraints together with the size of the deposit suggest a time-averaged rate of base-metal sulphide deposition of about 10-100 t/year. Peak rates were likely one to possibly two orders of magnitude above time-averaged rates, hence 100-1000 t/year or higher. Detrital zircon ages on greywackes in the structural footwall to the deposit support structural observations that the metasediments are unrelated and significantly younger than the volcanics that host the deposit. All greywackes near Kidd Creek are younger that 2699 Ma and should be included in the Porcupine Group, which is redefined to include 'Keewatin-age' greywacke turbidites that overlie the Krist Fragmental unit, but are themselves overlain by polymict conglomerates at the base of the Timiskaming sequence. The Prosser Porphyry, a quartz-plagioclase-porphyritic granitoid stock northeast of Kidd Creek, is dated at 2663.3-3.4+3.6 Ma, supporting structural observations that it is not a synvolcanic intrusion. (author). 54 refs., 5 tabs.,5 figs

  1. Health Monitoring for Coated Steel Belts in an Elevator System


    Yimei Mao; Zuoying Huang; Guiyun Tian; Hui Zhao; Huaming Lei


    This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of ...

  2. Device for continuous tare measurement at belt weighers

    International Nuclear Information System (INIS)

    The described device can be used for belt weighers connected with a computing unit. Its development has been aimed at measuring the weight of the belt without standstill. This could be achieved by arranging radiation sources and detectors over the whole width of the belt and transforming the radiation attenuation into weight equivalents with the aid of an evaluation unit connected to the computing unit

  3. Car safety belts: a study of two models adapted for people with arthritis. (United States)

    Arie, E


    People with arthritis find car seat belts difficult to use. Sixteen arthritic patients and 19 healthy volunteers completed a comparative study of one standard inertia-reel belt and two adapted inertia-reel belts with reduced retraction forces. Those with arthritis were strong enough to use the standard belt but both adapted belts had features making them easier to use. PMID:3708235

  4. Rirang Uranium Ore Processing System Design Horizontal Belt Filter

    International Nuclear Information System (INIS)

    Horizontal belt filter one of the solid-liquid separation process equipment. The design of Horizontal Belt Filter have been conducted for capacity of 250 g/minute. The result obtained was filtering velocity of 0,4 g/cm2 minute. The linear belt speeds 100 cm/minute. The length and width of the belt 125 cm also the filtering cycle of 1,25 minute. The operation of that equipment give result about 77,9 - 79,1% of product cake

  5. Health Monitoring for Coated Steel Belts in an Elevator System

    Directory of Open Access Journals (Sweden)

    Huaming Lei


    Full Text Available This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of the most dangerous section as well as other ones along the whole belts.

  6. Predicting Facies Patterns within Fluvial Channel Belts (United States)

    Willis, B. J.; Sech, R.; Sun, T.; Pyrcz, M.


    Reservoirs (aquifers) in fluvial channel belt sandstones can have very different subsurface flow behavior depending on the degree and distribution of internal heterogeneities. Fluvial channel belts are composed of multiple "storeys" formed as individual channel segments increase in sinuosity and then are cut off and abandoned. Heterogeneities are defined by depositional variations across storeys and inter-story connectivity patterns along the channel belt. Although commonly inferred to reflect the formative river pattern (sinuosity & braiding), the spatial arrangement of facies depend most directly on the relative preservation of deposits formed within different areas of the migrating channels and the lateral stacking arrangement of storeys due to style of bend cutoff. Grains are poorly sorted across the inner bank along upstream parts of channel bends and become better sorted laterally in downstream areas adjacent to a deeper thalweg scour. If deposition occurs evenly along the entire inner bank (bar), this grain size pattern leads to an elliptical body in planview with weak vertical grain size trends upstream and more fining-upward trend downstream. As channel bend segments migrate to a greater extent downstream, preserved inner-bank-bar deposits are increasingly dominated by upward-fining deposits and more outer-bank-deposits are preserved ("concave bank" deposits). Although concave bank deposits have highly variable character in different systems, vertical-grainsize trends tend to be weaker in straighter systems dominated by downstream-accretion, and more strongly upward-fining in higher sinuosity systems where these deposits form by eddy accretion or low flow aggradation. River cutoffs of straighter channel segments abandon slowly, leading to more gradual vertical fining. Subsurface heterogeneity prediction requires documentation of shape and character of deposits preserved in different zones within the channel (upstream and downstream inner bank, concave bank

  7. Energy in corn belt crop production

    Energy Technology Data Exchange (ETDEWEB)

    Lockeretz, W.; Klepper, R.; Gertler, M.; Fast, S.; O' Leary, D.


    The study presents data on the quantity and cost of the energy used to produce corn, soybeans, and wheat in the western part of the Corn Belt in 1974. The analysis covers fuel for field equipment, energy required to manufacture fertilizers and pesticides, and energy for drying corn. Corn is the most energy-intensive of the three crops studied, with soybeans the lowest. The cost of energy for crop production amounts to 11%, 8%, and 6% of the overall direct production costs for corn, wheat, and soybeans, respectively. These energy costs come to less than 3% of the value of the crop in all three cases. (GRA)

  8. Meningococcal carriage in the African meningitis belt



    A meningococcal serogroup A polysaccharide/tetanus toxoid conjugate vaccine (PsA-TT) (MenAfriVac#x2122;) is being deployed in countries of the African meningitis belt. Experience with other polysaccharide/protein conjugate vaccines has shown that an important part of their success has been their ability to prevent the acquisition of pharyngeal carriage and hence to stop transmission and induce herd immunity. If PsA-TT is to achieve the goal of preventing epidemics, it must be able to prevent ...

  9. Parametric resonances of convection belt system

    Institute of Scientific and Technical Information of China (English)

    Zhi-an YANG; Gao-feng LI


    Based on the Coriolis acceleration and the Lagrangian strain formula,a generalized equation for the transverse vibration system of convection belts is derived using Newton's second law.The method of multiple scales is directly applied to the governing equations,and an approximate solution of the primary parameter resonance of the system is obtained.The detuning parameter,cross-section area,elastic and viscoelastic parameters,and axial moving speed have a significant influences on the amplitudes of steady-state response and their existence boundaries.Some new dynamical phenomena are revealed.

  10. Inclusões fluidas crepitadas, fluidos hipersalinos e aquo-carbônicos em quartzo associado a rochas micáceas no Granito Xinguara - Terreno Granito-Greenstone de Rio Maria, PA Decrepitated fluid inclusions, aqueous-carbonic and hypersaline fluids in quartz associated to micaceous rocks in the Xinguara Granite - Rio Maria Granite - Greenstone terrain, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Leopoldo Weber


    Full Text Available As rochas micáceas encontradas no Granito Xinguara, terreno Granito-Greenstone de Rio Maria, Pará, são compostas por muscovita e clorita com níveis de quartzo intercalados, que formam uma xistosidade bem desenvolvida. Essa xistosidade é cortada por veios de quartzo. Ambas as gerações de quartzo apresentam os mesmos tipos de inclusões fluidas em halos ou trilhas secundárias de composições variadas entre aquosas, aquo-carbônicas e saturadas em torno de grandes inclusões primárias crepitadas ou em trilhas transgranulares secundárias. A grande variação de temperaturas de homogeneização, a alta salinidade, as evidências de estrangulamento e a existência das inclusões crepitadas permitem supor forte influência de alterações pós-formacionais e reequilíbrio relacionados à intrusão do granito. Essas rochas foliadas são, portanto, enclaves metassedimentares afetados por fluidos graníticos hipersalinos aquo-carbônicos.The micaceous rocks occurring in the Xinguara Granite, Rio Maria Granite-Greenstone terrain, Pará State, Brazil, are composed of muscovite and chlorite with quartz levels intercalated forming a well developed schistosity. This schistosity is cut by quartz veins. Both quartz generations show the same aqueous, aqueous-carbonic and halite-bearing fluid inclusions either in secondary inclusions halos and trails surrounding decrepitated primary fluid inclusions or in transgranular secondary trails. A wide variation of homogenization temperatures, high salinity, necking down and the decrepitated inclusions existence indicates strong influence of post-formational alteration and reequilibration linked to the granite intrusion. These foliated rocks are metasedimentary enclaves affected by late hypersaline aqueous-carbonic granitic fluids.

  11. Early Archaean collapse basins, a habitat for early bacterial life. (United States)

    Nijman, W.

    For a better definition of the sedimentary environment in which early life may have flourished during the early Archaean, understanding of the basin geometry in terms of shape, depth, and fill is a prerequisite. The basin fill is the easiest to approach, namely from the well exposed, low-grade metamorphic 3.4 - 3.5 Ga rock successions in the greenstone belts of the east Pilbara (Coppin Gap Greenstone Belt and North Pole Dome) in West Australia and of the Barberton Greenstone Belt (Buck Ridge volcano-sedimentary complex) in South Africa. They consist of mafic to ultramafic volcanic rocks, largely pillow basalts, with distinct intercalations of intermediate to felsic intrusive and volcanic rocks and of silicious sediments. The, partly volcaniclastic, silicious sediments of the Buck Ridge and North Pole volcano-sedimentary complexes form a regressive-transgressive sequence. They were deposited close to base level, and experienced occasional emersion. Both North Pole Chert and the chert of the Kittys Gap volcano-sedimentary complex in the Coppin Gap Greenstone Belt preserve the flat-and-channel architecture of a shallow tidal environment. Thickness and facies distribution appear to be genetically linked to systems, i.e. arrays, of syn-depositionally active, extensional faults. Structures at the rear, front and bottoms of these fault arrays, and the fault vergence from the basin margin towards the centre characterize the basins as due to surficial crustal collapse. Observations in the Pilbara craton point to a non-linear plan view and persistence for the basin-defining fault patterns over up to 50 Ma, during which several of these fault arrays became superposed. The faults linked high-crustal level felsic intrusions within the overall mafic rock suite via porphyry pipes, black chert veins and inferred hydrothermal circulations with the overlying felsic lavas, and more importantly, with the cherty sediments. Where such veins surfaced, high-energy breccias, and in the

  12. Fading of Jupiter's South Equatorial Belt (United States)

    Sola, Michael A.; Orton, Glenn; Baines, Kevin; Yanamandra-Fisher, Padma


    One of Jupiter's most dominant features, the South Equatorial Belt, has historically gone through a "fading" cycle. The usual dark, brownish clouds turn white, and after a period of time, the region returns to its normal color. Understanding this phenomenon, the latest occurring in 2010, will increase our knowledge of planetary atmospheres. Using the near infrared camera, NSFCAM2, at NASA's Infrared Telescope Facility in Hawaii, images were taken of Jupiter accompanied by data describing the circumstances of each observation. These images are then processed and reduced through an IDL program. By scanning the central meridian of the planet, graphs were produced plotting the average values across the central meridian, which are used to find variations in the region of interest. Calculations using Albert4, a FORTRAN program that calculates the upwelling reflected sunlight from a designated cloud model, can be used to determine the effects of a model atmosphere due to various absorption, scattering, and emission processes. Spectra that were produced show ammonia bands in the South Equatorial Belt. So far, we can deduce from this information that an upwelling of ammonia particles caused a cloud layer to cover up the region. Further investigations using Albert4 and other models will help us to constrain better the chemical make up of the cloud and its location in the atmosphere.

  13. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F


    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  14. Stabilization of electrostatic accelerator charging belt current

    International Nuclear Information System (INIS)

    For the purpose of improving reliability and quality of electrostatic accelerator basic parameters the stabilizer of charging belt current is developed. The stabilizer consists of two units: high-voltage unit and control unit. The charging rectifier assures voltage up to 60 kV at total current load of 750 μA. For the EG- 2.5 and the EGP-10 M accelerators supply circuits of charging device with an earth screen and posAitive voltage supply the needles. t the EGP-10-1 accelerator negative charging voltage is supplied to the screens of the charging device. ''Plus'' of the rectifier is earthed. Charging and recharging are performed by means of brushes slipping over the internal belt side. At all accelerators the stability of charging current mean value is not worse 0.1%. The highest response of the system are obtained at the EG-2.5 accelerator for account of rectifier load by charging current and instrument resistor from 140 to 400 MOhm

  15. 30 CFR 57.4263 - Underground belt conveyors. (United States)


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground belt conveyors. 57.4263 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Firefighting Equipment § 57.4263 Underground belt conveyors. Fire protection shall...

  16. Safety belt usage in Finland and in other Nordic countries.

    NARCIS (Netherlands)

    Valtonen, J.


    Legislation has played a significant role in increasing safety belt usage in Finland and in the other Nordic countries. Publicity and enforcement have, however, been required to support the legislation. The development of safety belt regulations has been nearly similar in all these countries, both i

  17. Canadian seat belt wearing rates, promotion programs, and future directions.

    NARCIS (Netherlands)

    Grant, B.A.


    On the basis of a national driver seat belt survey conducted in Canada each year, the most important results are presented. A number of programmes for increasing seat belt use has been evaluated in Canada. Finally, a description is given of some of the current and planned activities within Canada wh

  18. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep


    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  19. A belt charging system for the Vivitron - design, early results

    International Nuclear Information System (INIS)

    A specific belt charging system has been designed, built and assembled for the 35 MV Vivitron. 100 m long belt is used. Together with main features of the design, experimental studies, tests in a pilot machine and the results of the very early tests of the real system are reviewed

  20. Experimental Measurements of Belt Gears in Newly Developed Device

    Directory of Open Access Journals (Sweden)

    Jozef Mascenik


    Full Text Available The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric motor and the tensioning forces are constant and the torque changes.

  1. Traffic restrictions due to wind on the Fehmarn Belt bridge

    DEFF Research Database (Denmark)

    Dellwik, E.; Mann, Jakob; Rosenhagen, G.


    same as used in this report and here the comparison is satisfactory. We estimate that the prospective Fehmarn Belt bridge will be closed roughly 2% of the timefor light roadway vehicles (unloaded trucks and caravans), corresponding to 7 days per year. This is slightly less than for the Fehmarnsund...... Bridge. For the Great Belt bridge the corresponding actual fraction is 1.5%, despite the fact that this bridge usesstricter criteria. The most important difference between the bridges in this connection is their orientation with respect to the prevailing wind direction. If all the large bridges (Øresund......, Great Belt and Fehmarn Belt) used the same criteria the FehmarnBelt bridge would be closed approximately twice as much as the two others. The majority of these restrictions are likely to take place in the winter time and can be significantly reduced with wind screens....

  2. A Study on the Vibration of the Charging Belt in an Electrostatic Accelerator

    Institute of Scientific and Technical Information of China (English)


    The vibration of the charging belt in an electrostatic accelerator has intense influences on the accelerator operation. A calculating model was set up in this paper to study the belt vibration. The results show that the belt tension, belt velocity and belt current all contribute to the belt vibration. There is an optimal relationship among the three factors by which the belt would run most smoothly. There exists a minimum value of optimal tension for various belt velocities. The vibrating frequency of the is generally around several Hz.

  3. Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

    Directory of Open Access Journals (Sweden)

    Jieyu Ding


    Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

  4. The Foundations of Radiation Belt Research (United States)

    Ludwig, G. H.


    phenomenon. It also provided the first hint that there were two distinct radiation belts, although that conclusion was not reached until later. Although that new information was quickly announced, the results of the high altitude nuclear detonations were kept secret until well into 1959. They clearly revealed the charged particle shells created by the Argos nuclear detonations. The next major step in mapping and understanding the high-intensity radiation involved the launch of deep space probes Pioneers III and IV in December 1958 and March 1959. Although both launches fell short in their primary objective, to reach the moon, they traveled far enough from the Earth to fully meet the needs of the scientific experiment. They very clearly showed the two-radiation belt structure, and mapped its extent. They also showed the probable effect of a magnetic storm on 25 February, thus indicating the direct influence of solar activity on the outer belt. By the end of 1959, the existence of the Van Allen Radiation Belts and their general structure were solidly established, early information about the composition of the radiation was appearing in print, and energetic work was under way to understand the physics of the processes involved.

  5. Space electronics: radiation belts set new challenges

    International Nuclear Information System (INIS)

    Telecommunications satellites have been in use since 1962 with the first satellite network (constellation) coming into operation in 1966. GPS systems have been available since the mid seventies. Until now, all these systems have avoided orbits which lie within the radiation belts. The latest constellation projects, offering much wider bandwidths, need to use orbits between 1500 and 2000 km, where the proton density is at its highest. The vulnerability of future generations of components can be predicted by extrapolating the behaviour of current devices. Screening is not a viable option due to cost and weight limitations in satellite applications. As a result, satellite and component manufacturers are seeking new methods of hardening components or making them more radiation tolerant in an environment where the radiation levels are ten times those currently experiences. (authors)

  6. Geometry, kinematics and evolution of the Tongbai orogenic belt

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoying; XU Bei; WANG Changqiu; ZHAN Sheng; DENG Rongjing


    The Tongbai orogenic belt (TOB) is composed of six tectonic units. From south to north these units are: Tongbai gneiss rise (TGR); Hongyihe-Luozhuang eclogite belt (HLE); Maopo-Hujiazhai igneous rock belt (MHI); Zhoujiawan flysch belt (ZFB); Yangzhuang greenschist belt (YGB); and Dongjiazhuang marble belt (DMB).The geometry and kinematic images of the TOB include: the antiformal structures caused by a later uplift process, the top-to-north ductile shear structure that related to a process that the ultrahigh pressure rocks are brought to surface, the top-to-south ductile shear thrust and the sinistrial shear structures related to a south-north direction compression, and the east-west direction fold structures in the upper crust. In the view of the multistage subduction-collision orogenic belt, according to the characters of petrology and its distribution, geometry, kinematics and structural chronology in these tectonic units, tectonic evolution of the TOB can be divided into four stages: oceanic crust subduction during 400-300 Ma, continental collision during 270-250 Ma, continental deep subduction and uplift during 250-205 Ma and doming deformation during 200-185 Ma.

  7. The optimization of steelcord belt splices; Optimierung von Stahlseilgurtverbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Hager, M. [Hannover Univ. (Germany); Keller, M. [ContiTech Transportbandsysteme GmbH, Northeim (Germany)


    Belt-conveyors have proven themselves for the continuous bulk conveying under technical and economic points of view for a long time. For long belt conveyors and big mass flows, steelcord conveyor belts technologically represent the state of the art. In a steelcord belt splice, the tensile force between the spliced belt ends is transmitted almost completely by locally differing shear forces in the rubber of the elastomer composite construction. Under the dynamically swelling load, to which the belt is exposed in operation, the splices represent the weakest part of a conveyor belt. In experimental examinations of this paper it was found, that the characteristic behavior of the material of the elastomer and the constructive design influences distortion behavior under force of steelcord belt test samples. As most important parameter of the compound design, the filler proves itself as the strongest influence on the dynamic shear modulus, which characterizes the non linear dynamic stiffness of the elastomer. The filling degree and the filler composition influence the degree of non linearity of the dynamic shear modulus and its complex components. On the basis of the results of the experimental examinations, an approximation model of the non linear dynamic shear modulus was employed, with which it is possible, to characterize the non linear, amplitude dependent material behavior of the examined elastomer. In the scope of this paper, a program system was developed on basis of the finite element method, that allows the arithmetical simulation of the force flow in steelcord belt splices and in highly stressed areas of the splices. (orig.)

  8. Detection of Small Kuiper Belt Objects by Stellar Occultations


    Stevenson, R


    Knowledge of the Kuiper Belt is currently limited to those objects that can be detected directly. Objects with diameters less than $\\sim$10km reflect too little light to be detected. These smaller bodies could contain most of the mass in the Kuiper Belt while the abundance of these bodies may constrain the distribution of mass. The overall size distribution of bodies within the Kuiper Belt can also be inferred from the relative abundances of sub-km and larger bodies. Stellar occultations are ...

  9. Into the Kuiper Belt: New Horizons Post-Pluto (United States)

    Harrison Parker, Alex; Spencer, John; Benecchi, Susan; Binzel, Richard; Borncamp, David; Buie, Marc; Fuentes, Cesar; Gwyn, Stephen; Kavelaars, JJ; Noll, Keith; Petit, Jean-Marc; Porter, Simon; Showalter, Mark; Stern, S. Alan; Sterner, Ray; Tholen, David; Verbiscer, Anne; Weaver, Hal; Zangari, Amanda


    New Horizons is now beyond Pluto and flying deeper into the Kuiper Belt. In the summer of 2014, a Hubble Space Telescope Large Program identified two candidate Cold Classical Kuiper Belt Objects (KBOs) that were within reach of New Horizons' remaining fuel budget. Here we present the selection of the Kuiper Belt flyby target for New Horizons' post-Pluto mission, our state of knowledge regarding this target and the potential 2019 flyby, the status of New Horizons' targeting maneuver, and prospects for near-future long-range observations of other KBOs.


    Directory of Open Access Journals (Sweden)

    Kazimierz JAMROZ


    Full Text Available The article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.

  11. Geochronologic studies in the Grants mineral belt

    International Nuclear Information System (INIS)

    Geologic observation coupled with radiometric age dating can be used to assess ages of ore formation and, in some cases, ages of sedimentation in the Grants mineral belt. Rb-Sr studies indicate the earliest mineralization is trend ore at Ambrosia Lake and Smith Lake, dated at 139 +- 9.5 m.y. This date is similar to that for barren-rock montmorillonite from the Jackpile sandstone (Late Jurassic): 142 +- 14 m.y.; it may be used, with caution, to indicate the minimum age of sedimentation for the Morrison Formation. Geologic evidence indicates epigenetic rather than syngenetic ore formation. Barren-rock montmorillonites from Ambrosia Lake yield a poorly defined isochron of 132 +- 26 m.y. Early formed ore at the Jackpile-Paguate mine, Laguna district, was remobilized and reprecipitated at 113 +- 7 m.y. This date is older than the range of dates for the Dakota Formation (Cretaceous) and Mancos Shale. The 113 +- 7 m.y. mid-Cretaceous date for the Jackpile-Paguate ore is consistent with geologic evidence; geologic control suggests that other ore deposits are post-Late Jurassic but pre-Dakota Formation. Based on geologic evidence, mineralization in the Dakota Formation is thought to be very young. Laramide mineralization (60 to 70 m.y.) is evidenced by the presence of some stack ore. At least one uranium deposit, located partly in oxidized ground at the main redox front of the Grants mineral belt, may represent Tertiary mineralization; the clay-mineral Rb-Sr systematics of this deposit have been severely perturbed. Younger mineralization is indicated by U-Pb dates on uranophane (9 to 10 m.y.), and Pleistocene mineralization is noted for some ore. U-Pb dates of U4+ -rich ore minerals cluster between 80 and 100 m.y., although some are as old as 140 to 150 m.y. K-Ar dates on clay minerals range from 49 to 138 m.y. The reasons for this scatter are not known, although loss of radiogenic 40Ar due to burial is probable

  12. Face-Saving Devices: Seat Belts and Air Bags (United States)

    ... page: Face-Saving Devices: Seat Belts and Air Bags Using ... 11 percent) suffered facial fractures -- nasal and mid-face fractures most often. Those most likely to suffer ...

  13. CRED REA Fish Team Belt Transect Survey at Laysan 2004 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Laysan in the...

  14. Back belts in occupational setting: what are the evidences?

    Directory of Open Access Journals (Sweden)

    João Marcos Bernardes


    Full Text Available Although, widely used the mechanisms of action and the effectiveness of back belts in the prevention of occupational low back disorders remains uncertain, generating controversy about its use. Therefore, the purpose of this study was to do a critical literature review about back belts use in the prevention of occupational low back pain in the occupational setting. In order to do that, a bibliographic research in the following data basis: Medline, SciELO and LILACS was conducted. There is evidence that back belts use reduces spine range of motion, however the studies about intra-abdominal pressure and muscle activity presented contradictory results, as the epidemiologic studies, not allowing the recommendation of its use in the prevention of occupational low back pain. Based on this literature review it is suggested therefore, the implementation of new studies, to confirm or not the effectiveness of back belts as personal protective equipment, in the prevention of occupational low back disorders.

  15. A Physical Model of Electron Radiation Belts of Saturn (United States)

    Lorenzato, L.; Sicard-Piet, A.; Bourdarie, S.


    Enrolling on the Cassini age, a physical Salammbô model for the radiation belts of Saturn have been developed including several physical processes governing the kronian magnetosphere. Results have been compared with Cassini MIMI LEMMS data.

  16. Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran (United States)

    Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza


    Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or


    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz


    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  18. Promoting automobile safety belt use by young children.


    Sowers-Hoag, K M; Thyer, B A; Bailey, J S


    A program using behavioral practice, assertiveness training, and social and contrived reinforcers was developed to establish and maintain automobile safety belt use by young children. Sixteen children (ages 4.8 to 7 years) who never used their safety belts during a 5-day preexperimental observation period were randomly assigned to two groups of eight each. A multiple baseline design across groups was used to evaluate the effectiveness of the training program. During the 8-day baseline period ...

  19. Back belts in occupational setting: what are the evidences?


    João Marcos Bernardes; Antonio Renato Pereira Moro


    Although, widely used the mechanisms of action and the effectiveness of back belts in the prevention of occupational low back disorders remains uncertain, generating controversy about its use. Therefore, the purpose of this study was to do a critical literature review about back belts use in the prevention of occupational low back pain in the occupational setting. In order to do that, a bibliographic research in the following data basis: Medline, SciELO and LILACS was conducted. There is evid...

  20. Tribological Properties of Metal V-Belt Type CVT Lubricant


    Keiichi Narita


    The priority for lubricant performance for metal V-belt-type CVT (B-CVTFs) should be the improvement of transmittable torque capacity between the belt and pulley plus excellent antishudder properties for lockup clutch used in B-CVTs. This study intends to investigate the effect of lubricant additives for improving these performances of B-CVTs. In addition, surface analysis techniques were utilized to gain a novel insight into the chemical composites and morphology of the tribofilms. As a resu...

  1. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰


    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  2. Occultation Searches for Kuiper Belt Objects

    CERN Document Server

    Cooray, A R; Cooray, Asantha; Farmer, Alison J.


    The occultation of background stellar sources by foreground Kuiper Belt Objects (KBOs) can be used to survey physical properties of the KBO population. We discuss statistics related to a KBO occultation survey, such as the event duration distribution, and suggest that occultation searches can be effectively used to probe the KBO size distribution below 10 km. In particular, we suggest that occultation surveys may be best suited to search for a turnover radius in the KBO size distribution due to collisions between small-size objects. For occultation surveys that monitor stellar sources near the ecliptic over a few square degrees, with time sampling intervals of order 0.1 sec and sensitivity to flux variations of a few percent or more, a turnover radius between 0.1 and 1.0 km can be probed. While occultation surveys will probe the low-radius limit and imaging surveys will detect KBOs of size 100 km or more, statistics of objects with sizes in the intermediate range of around 1 km to 100 km will likely remain un...

  3. Detecting Mass Loss in Main Belt Asteroids (United States)

    Sandberg, Erik; Rajagopal, Jayadev; Ridgway, Susan E.; Kotulla, Ralf C.; Valdes, Francisco; Allen, Lori


    Sandberg, E., Rajagopal, J., Ridgway, S.E, Kotulla, R., Valdes, F., Allen, L.The Dark Energy Camera (DECam) on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) is being used for a survey of Near Earth Objects (NEOs). Here we attempt to identify mass loss in main belt asteroids (MBAs) from these data. A primary motivation is to understand the role that asteroids may play in supplying dust and gas for debris disks. This work focuses on finding methods to automatically pick out asteroids that have qualities indicating possible mass loss. Two methods were chosen: looking for flux above a certain threshold in the asteroid's radial profile, and comparing its PSF to that of a point source. After sifting through 490 asteroids, several have passed these tests and should be followed up with a more rigorous analysis.Sandberg was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829)

  4. Radiation belts study in RESONANCE project (United States)

    Mogilevsky, Mikhail; Demekhov, Andrei; Zelenyi, Lev; Petrukovich, Anatoly; Shklyar, David

    The Earth’s inner magnetosphere is an important part of space weather framework. Outer radiation belt is a home for numerous communication and navigation satellites. But besides this practical problem, this region is a theoretical nugget. Hot magnetospheric, cold plas¬mospheric, and, in contrast, high energy plasma coexist here. Such non-equilibrium state of plasma is glued by various plasma oscillations actively interacting with particles and resulting, in particular, in spatial and velocity diffusion. Diffusion influences acceleration and precipitation of particles and defines their life¬time in the Earth’s magnetosphere. The project RESONANCE is aimed to study the whole complex of these issues, both practical (space weather), and fundamental (nonlinear plasma dynamics). The project RESONANCE is a part of the Russian Federal State Program. Lavochkin Association is responsi¬ble for preparation and testing of the satellites. Space Research Institute of the Russian Academy of Sciences is a leading scientific organization. Besides Russian scientists, specialists from Austria, Bulgaria, Czech Re¬public, Finland, France, Germany, Greece, Poland, Slovakia, Ukraine, USA take part.

  5. On-conveyor belt determination of ash in coal

    International Nuclear Information System (INIS)

    A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error

  6. Forming the Cold Classical Kuiper Belt in a light Disk

    CERN Document Server

    Shannon, Andrew; Lithwick, Yoram


    Large Kuiper Belt Objects are conventionally thought to have formed out of a massive planetesimal belt that is a few thousand times its current mass. Such a picture, however, is incompatible with multiple lines of evidence. Here, we present a new model for the conglomeration of Cold Classical Kuiper belt objects, out of a solid belt only a few times its current mass, or a few percent of the solid density in a Minimum Mass Solar Nebula. This is made possible by depositing most of the primordial mass in grains of size centimetre or smaller. These grains collide frequently and maintain a dynamically cold belt out of which large bodies grow efficiently: an order-unity fraction of the solid mass can be converted into large bodies, in contrast to the ~0.1% efficiency in conventional models. Such a light belt may represent the true outer edge of the Solar system, and it may have effectively halted the outward migration of Neptune. In addition to the high efficiency, our model can also produce a mass spectrum that pe...

  7. Public Access to Digital Material; A Call to Researchers: Digital Libraries Need Collaboration across Disciplines; Greenstone: Open-Source Digital Library Software; Retrieval Issues for the Colorado Digitization Project's Heritage Database; Report on the 5th European Conference on Digital Libraries, ECDL 2001; Report on the First Joint Conference on Digital Libraries. (United States)

    Kahle, Brewster; Prelinger, Rick; Jackson, Mary E.; Boyack, Kevin W.; Wylie, Brian N.; Davidson, George S.; Witten, Ian H.; Bainbridge, David; Boddie, Stefan J.; Garrison, William A.; Cunningham, Sally Jo; Borgman, Christine L.; Hessel, Heather


    These six articles discuss various issues relating to digital libraries. Highlights include public access to digital materials; intellectual property concerns; the need for collaboration across disciplines; Greenstone software for construction and presentation of digital information collections; the Colorado Digitization Project; and conferences…

  8. Delivery of meteorites from the asteroid belt (United States)

    Nolan, Michael Craig

    The process of the delivery of meteorites to the surface of the Earth from plausible source regions such as the asteroid belt is currently understood in general terms, but important uncertainties and conflicts remain to be resolved. Stochastic effects of the rare disruptions of large asteroids on the population of meteorite-sized Earth-crossing asteroids can change the flux and the proportions of compositional types in the infalling meteorite population. These changes can be significant in magnitude over timescales of 108 years. Changes of the order of 1 percent can be expected on timescales of 105-106 y, consistent with small differences between the Antarctic meteorites and modern falls. The magnitude of changes depends strongly on poorly-understood details of collisions. Asteroids 961 Gaspra and 243 Ida were recently imaged by the Galileo spacecraft. I use a numerical hydrocode model to examine the outcomes of various sire impacts into targets the sizes of these asteroids. A shock wave fractures the asteroid in advance of crater excavation flow; thus, for impactors larger than 100 m, impacting at 5.3 km s-1, tensile strength is unimportant in these bodies, whether they are initially intact or are 'rubble piles'. Because of the shock-induced fracture, impact results are controlled by gravity. Therefore these asteroids are much more resistant to catastrophic disruption than predicted by previous estimates, which had assumed that strength was controlling these processes for rock targets. Fracture of km-size asteroids is different from fracture in terrestrial experiments using few-cm targets. The composition distribution of delivered meteorites depends on the outcomes of such asteroid impacts.

  9. Super-Comet or Big Asteroid Belt? (United States)


    [figure removed for brevity, see original site] Figure 1: Spectrograph of HD 69830 This graph of data from NASA's Spitzer Space Telescope demonstrates that the dust around a nearby star called HD 69830 (upper line) has a very similar composition to that of Comet Hale-Bopp. Spitzer spotted large amounts of this dust in the inner portion of the HD 69830 system. The bumps and dips seen in these data, or spectra, represent the 'fingerprints' of various minerals. Spectra are created when an instrument called a spectrograph spreads light out into its basic parts, like a prism turning sunlight into a rainbow. These particular spectra reveal the presence of the silicate mineral called olivine, and more specifically, a type of olivine called forsterite, which is pictured in the inset box. Forsterite is a bright-green gem found on Earth, on the 'Green Sand Beach' of Hawaii among other places; and in space, in comets and asteroids. Because the dust around HD 69830 has a very similar make-up to that of Comet Hale-Bopp, astronomers speculate that it might be coming from a giant comet nearly the size of Pluto. Such a comet may have been knocked into the inner solar system of HD 69830, where it is now leaving in its wake a trail of evaporated dust. Nonetheless, astronomers say the odds that Spitzer has caught a 'super-comet' spiraling in toward its star - an unusual and relatively short-lived event - are slim. Instead, they favor the theory that the observed dust is actually the result of asteroids banging together in a massive asteroid belt. The data of HD 69830's dust were taken by Spitzer's infrared spectrograph. The data of Comet Hale-Bopp were taken by the European Space Agency's Infrared Observatory Satellite. The picture of forsterite comes courtesy of Dr. George Rossman, California Institute of Technology, Pasadena.

  10. Meningococcal carriage in the African meningitis belt (United States)


    A meningococcal serogroup A polysaccharide/tetanus toxoid conjugate vaccine (PsA-TT) (MenAfriVac#x2122;) is being deployed in countries of the African meningitis belt. Experience with other polysaccharide/protein conjugate vaccines has shown that an important part of their success has been their ability to prevent the acquisition of pharyngeal carriage and hence to stop transmission and induce herd immunity. If PsA-TT is to achieve the goal of preventing epidemics, it must be able to prevent the acquisition of pharyngeal carriage as well as invasive meningococcal disease and whether PsA-TT can prevent pharyngeal carriage needs to be determined. To address this issue, a consortium (the African Meningococcal Carriage (MenAfriCar) consortium) was established in 2009 to investigate the pattern of meningococcal carriage in countries of the African meningitis belt prior to and after the introduction of PsA-TT. This article describes how the consortium was established, its objectives and the standardised field and laboratory methods that were used to achieve these objectives. The experience of the MenAfriCar consortium will help in planning future studies on the epidemiology of meningococcal carriage in countries of the African meningitis belt and elsewhere. Un vaccin conjugué contenant un polysaccharide du sérogroupe A méningococcique et une anatoxine du tétanos (PsA-TT) (MenAfriVac™) est en cours de déploiement dans les pays de la ceinture africaine de la méningite. L’ expérience avec d’ autres vaccins conjugués polysaccharide/protéine a montré qu’ une partie importante de leur succès a été leur capacité à empêcher l’ acquisition du portage pharyngé et donc à arrêter la transmission et à induire une immunité de group. Si PsA-TT doit d’ atteindre l’ objectif de prévenir les épidémies, il devrait être en mesure d’ empêcher l’ acquisition du portage pharyngé ainsi que la méningococcie invasive et le fait que PsA-TT puisse emp

  11. Electrospun nanofiber belts made from high performance copolyimide

    International Nuclear Information System (INIS)

    Electrospun nanofibers based on copolyimides were made, aiming at finding a promising method for improving the mechanical properties of electrospun polyimide nanofibers. The copolyimide had a backbone consisting of 3,3',4,4'-biphenyl-tetracarboxylic dianhydride (BPDA), biphenylamide (BPA) and 4,4'-oxydianiline (ODA) residues. The structure and composition of the copolyimide was controlled by the ratio of rigid BPA and flexible ODA moieties. The electrospun copolyimide nanofibers were collected in the form of a belt using a rotating disc with a rim of 8 mm width. Scanning electron microscopy (SEM), infrared (IR) spectroscopy, x-ray scattering and tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to characterize the nanofiber belts. The nanofibers had a diameter range from 80 to 300 nm and were well aligned in the belts. The thermal stability of the nanofiber belts was over 460 deg. C. The tensile test showed that the copolyimide nanofiber belts had much better mechanical properties than either of the flexible and rigid homo-polyimide (homo-PI) nanofiber belts. The tensile strength, modulus and elongation to break of the copolyimide nanofiber belt with BPA/ODA ratio of 40/60 are respectively 1.1 ± 0.1 GPa, 6.2 ± 0.7 GPa and 20.8 ± 1.2%, compared to 459 ± 36 MPa, 2.1 ± 0.3 GPa and 41.3 ± 2.2% for BPDA/ODA homo-PI as well as 384 ± 18 MPa, 11.5 ± 0.6 GPa and 3.9 ± 0.1% for BPDA/BPA homo-PI. The important feature is that the electrospun polymer nanofibers can be made very strong by using copolyimides as spinning materials

  12. Geological characteristics of dike-structural belt in Taoshan orefield and its relationship to uranium deposits

    International Nuclear Information System (INIS)

    Taoshan uranium field is occurred in the Taoshan composite batholith in the central Jiangxi Province. The main body of the batholith was formed in Triassic-Early Cretaceous. In Late Cretaceous-Eogene, NE strike fault structure and dike belt were developed in the batholith. From the north to the south, there are successive Xiaobu-Matian dike-structural belt, Wangnitian dike- structural belt, Huangtan-Yueyuan dike-structural belt, Xibei-Shangluo dike-structural belt, Jipoling dike-structural belt, Wangce dike-structural belt and Shiyuanling dike-structural belt. These belts are controlled by the main fault, share the same space and similar time with the uranium mineralization, which is one of the important factors in positioning the uranium ore as well as the prospecting direction of exploration. (authors)


    Directory of Open Access Journals (Sweden)

    Wang Kaiying


    Full Text Available The Shanxi tectonic belt is a historically earthquakeabundant area. For the majority of strong earthquakes in this area, the distribution of earthquake foci was controlled by the N–S oriented local structures on the tectonic belt. Studies of the present stress state of the Shanxi tectonic belt can contribute to the understanding of the relationship between strong earthquakes’ occurrence and their structural distribution and also facilitate assessments of regional seismic danger and determination of the regions wherein strong earthquakes may occur in future. Using the Cataclastic Analysis Method (CAM, we performed stress inversion based on the focal mechanism data of earthquakes which took place in the Shanxi tectonic belt from 1967 to 2010. Our results show that orientations of the maximum principal compressive stress axis of the Shanxi tectonic belt might have been variable before and after the 2001 Kunlun MS=8.1 strong earthquake, with two different superior trends of the NW–SE and NE–SW orientation in different periods. When the maximum principal compressive stress axis is oriented in the NE–SW direction, the pattern of the space distribution of the seismic events in the Shanxi tectonic belt shows a trend of their concentration in the N–S oriented tectonic segments. At the same time, the stress state is registered as horizontal shearing and horizontal extension in the N–S and NE–SW oriented local segments in turn. When the maximum principal compressive stress axis is NW–SE oriented, the stress state of the N–S and NE–SW oriented tectonic segments is primarily registered as horizontal shearing. Estimations of plunges of stress axes show that seismicity in the Shanxi belt  corresponds primarily to the activity of lowangle faults, and highangle stress sites are located in the NE–SW oriented extensional tectonic segments of the Shanxi belt. This indicates that the stress change of the Shanxi belt is

  14. Evolution of the Bhandara-Balaghat granulite belt along the southern margin of the Sausar Mobile Belt of central India

    Indian Academy of Sciences (India)

    H M Ramachandra; Abhinaba Roy


    The Bhandara-Balaghat granulite (BBG) belt occurs as a 190 km long, detached narrow, linear, NE-SW to ENE-WSW trending belt that is in tectonic contact on its northern margin with the Sausar Group of rocks and is bordered by the Sakoli fold belt in the south. The Bhandara part of the BBG belt is quite restricted, comprising a medium to coarse grained two-pyroxene granulite body that is of gabbroic composition and preserves relic igneous fabric. The main part of the belt in Arjuni-Balaghat section includes metasedimentary (quartzite, BIF, Al- and Mg-Al metapelites) and metaigneous (metaultramafic, amphibolite and two-pyroxene granulite) protoliths interbanded with charnockite and charnockitic gneiss. These rocks, occurring as small bands and enclaves within migmatitic and granitic gneisses, show polyphase deformation and metamorphism. Geochemically, basic compositions show tholeiitic trend without Fe-enrichment, non-komatitic nature, continental affinity and show evolved nature. Mineral parageneses and reaction textures in different rock compositions indicate early prograde, dehydration melt forming reactions followed by orthopyroxene stability with or without melt. Coronitic and symplectitic garnets have formed over earlier minerals indicating onset of retrograde IBC path. Evidences for high temperature ductile shearing are preserved at places. Retrogressive hydration events clearly post-date the above paths. The present study has shown that the BBG belt may form a part of the Bastar Craton and does not represent exhumed oceanic crust of the Bundelkhand Craton. It is further shown that rocks of the BBG belt have undergone an earlier high-grade granulite metamorphism at 2672 ± 54 Ma (Sm-Nd age) and a post-peak granulite metamorphism at 1416 ± 59 Ma (Sm-Nd age, 1380 ± 28 Ma Rb-Sr age). These events were followed by deposition of the Sausar supracrustals and Neoproterozoic Sausar orogeny between 973 ± 63 Ma and 800 ± 16 Ma (Rb-Sr ages).

  15. Rotationally driven 'zebra stripes' in Earth's inner radiation belt. (United States)

    Ukhorskiy, A Y; Sitnov, M I; Mitchell, D G; Takahashi, K; Lanzerotti, L J; Mauk, B H


    Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn, the electric field produced in the inner magnetosphere by Earth's rotation can change the velocity of trapped particles by only about 1-2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth's inner radiation belt are organized in regular, highly structured and unexpected 'zebra stripes', even when the solar-wind activity is low. Modelling reveals that the patterns are produced by Earth's rotation. Radiation-belt electrons are trapped in Earth's dipole-like magnetic field, where they undergo slow longitudinal drift motion around the planet because of the gradient and curvature of the magnetic field. Earth's rotation induces global diurnal variations of magnetic and electric fields that resonantly interact with electrons whose drift period is close to 24 hours, modifying electron fluxes over a broad energy range into regular patterns composed of multiple stripes extending over the entire span of the inner radiation belt. PMID:24646996

  16. Fall Protection Characteristics of Safety Belts and Human Impact Tolerance. (United States)

    Hino, Yasumichi; Ohdo, Katsutoshi; Takahashi, Hiroki


    Many fatal accidents due to falls from heights have occurred at construction sites not only in Japan but also in other countries. This study aims to determine the fall prevention performance of two types of safety belts: a body belt(1)), which has been used for more than 40 yr in the Japanese construction industry as a general type of safety equipment for fall accident prevention, and a full harness(2, 3)), which has been used in many other countries. To determine human tolerance for impact trauma, this study discusses features of safety belts with reference(4-9)) to relevant studies in the medical science, automobile crash safety, and aircrew safety. For this purpose, simple drop tests were carried out in a virtual workplace to measure impact load, head acceleration, and posture in the experiments, the Hybrid-III pedestrian model(10)) was used as a human dummy. Hybrid-III is typically employed in official automobile crash tests (New Car Assessment Program: NCAP) and is currently recognized as a model that faithfully reproduces dynamic responses. Experimental results shows that safety performance strongly depends on both the variety of safety belts used and the shock absorbers attached onto lanyards. These findings indicate that fall prevention equipment, such as safety belts, lanyards, and shock absorbers, must be improved to reduce impact injuries to the human head and body during falls. PMID:25152087


    Energy Technology Data Exchange (ETDEWEB)

    Turrini, D.; Coradini, A.; Magni, G., E-mail: [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, 00133, Rome (Italy)


    The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.

  18. Gravity inferred subsurface structure of Gadwal Schist belt, Andhra Pradesh

    Indian Academy of Sciences (India)

    G Ramadass; I B Ramaprasada Rao; N Srinivasulu


    Detailed gravity data collected across the Gadwal schist belt in the state of Andhra Pradesh show an 8.4 mgal residual gravity anomaly associated with meta-sediments/volcanics of the linear NNW-SSE trending schist belt that shows metamorphism from green schist to amphibolite facies. This schist belt is flanked on either side by the peninsular gneissic complex. The elevation and slab Bouguer corrected residual gravity profile data were interpreted using 2-D prism models. The results indicate a synformal structure having a width of 1.8 km at the surface, tapering at a depth of about 2.6 km with a positive density contrast of 0.15 gm/cc with respect to the surrounding peninsular gneissic complex.

  19. Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

    Institute of Scientific and Technical Information of China (English)


    The purpose of this paper is to analyze the regional fault systems of Qaidam basin and adjacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault systems occurred in the Qaidam and adjacent mountain belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunlun Mountain fault system; (3)Altun strike-slip fault system; (4)Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accumulation belt.

  20. TAKRAF belt conveyors - effective means of transport for bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Peterman, L.


    Presents belt conveyor types produced by TAKRAF, especially those intended for use at surface mines. The FAM works (Transport Equipment) produces belt conveyors 800-1,400 mm wide, with 2.09-5.24 m/s belt velocity, 460-3,750 m/sup 3//h capacity, max. feed distance 2,500 m and (1-5)x55 kW drive power. The drive stations are based on pontoons or caterpillar vehicles while the end-stations are based on pontoons. Charging hoppers have autonomic drives and are mobile on rail. The described conveyors can also be used in power plants. The FAM works produces 650-800 mm wide conveyors for thermal electric power stations. The conveyors are equipped with metal detectors and metal separators.

  1. Relativistic surfatron process for Landau resonant electrons in radiation belts

    CERN Document Server

    Osmane, A


    Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\\theta$ in close proximity to a critical propagation $\\theta_\\textrm{c}$ associated with a Hopf--Hopf bifurcation condition. In this report, we extend previous studies to reach greater modeling capacities for the study of electrons in radiation belts by including longitudinal wave effects and inhomogeneous magnetic fields. We find that even though both effects can limit the surfatron acceleration of electrons in radiation belts, gains in energy of the order of 100 keV, taking place on the order of ten milliseconds, are sufficiently strong for the mechanism to be relevant to radiation belt dynamics.

  2. The Belt voice: Acoustical measurements and esthetic correlates (United States)

    Bounous, Barry Urban

    This dissertation explores the esthetic attributes of the Belt voice through spectral acoustical analysis. The process of understanding the nature and safe practice of Belt is just beginning, whereas the understanding of classical singing is well established. The unique nature of the Belt sound provides difficulties for voice teachers attempting to evaluate the quality and appropriateness of a particular sound or performance. This study attempts to provide answers to the question "does Belt conform to a set of measurable esthetic standards?" In answering this question, this paper expands on a previous study of the esthetic attributes of the classical baritone voice (see "Vocal Beauty", NATS Journal 51,1) which also drew some tentative conclusions about the Belt voice but which had an inadequate sample pool of subjects from which to draw. Further, this study demonstrates that it is possible to scientifically investigate the realm of musical esthetics in the singing voice. It is possible to go beyond the "a trained voice compared to an untrained voice" paradigm when evaluating quantitative vocal parameters and actually investigate what truly beautiful voices do. There are functions of sound energy (measured in dB) transference which may affect the nervous system in predictable ways and which can be measured and associated with esthetics. This study does not show consistency in measurements for absolute beauty (taste) even among belt teachers and researchers but does show some markers with varying degrees of importance which may point to a difference between our cognitive learned response to singing and our emotional, more visceral response to sounds. The markers which are significant in determining vocal beauty are: (1) Vibrancy-Characteristics of vibrato including speed, width, and consistency (low variability). (2) Spectral makeup-Ratio of partial strength above the fundamental to the fundamental. (3) Activity of the voice-The quantity of energy being produced. (4

  3. Structural framework of the Zagros Fold-Thrust Belt, Iran

    Energy Technology Data Exchange (ETDEWEB)

    Sepehr, M.; Cosgrove, J.W. [Imperial College, London (United Kingdom). Royal School of Mines


    Data gleaned from the literature on the Zagros have been compiled and used in conjunction with new interpretations to provide a better picture of the structures, sedimentation history and deformation of this hydrocarbon rich Mountain Belt. The belt parallel Mountain Front, the N-S trending Kazerun, lzeh and E-W trending Bala Rud Fault Zones are defined as the master structural elements of the Belt. These fault zones divide the Zagros basin into zones with different stratigraphic successions and different rheological profiles. This resulted in different structural styles developing along the belt during the subsequent collision. The Kazerun and lzeh Fault Zones acted as the depositional system transition zone between the Lurestan and Fars regions in Jurassic-Cretaceous time and partly controlled the distribution of the Kazhdumi Formation (one of the major source rocks). By the end of the Cretaceous the NW-SE trending Mountain Front Fault divided the present Folded Belt of the Zagros into a major foreland basin to the southwest, and a piggyback basin to the northeast. Activity along other major (transfer) fault zones including the lzeh, Kazerun and Bala Rud Fault zones occurred at this time and controlled the sedimentation and subsidence of the Dezful Embayment the main target region for hydrocarbon exploration. These fault zones controlled the thickness of the Asmari Formation (one of the main reservoirs) and also the considerable thickness and facies changes of the Gachsaran Formation (the major seal to the Asmari Formation). The present morphology of the mountain belt is interpreted as being mainly related to the pinning of the Mountain Front Fault to the northwest of the Dezful Embayment and to the north of the Strait of Hormuz. (author)

  4. Pn anisotropic tomography under the entire Tienshan orogenic belt (United States)

    Zhou, Zhigang; Lei, Jianshe


    We present a new anisotropic tomography of the uppermost mantle under the Tienshan orogenic belt and surrounding regions using a number of Pn arrival-time data hand-picked from portable seismic stations and chosen from the Xinjiang provincial observation bulletins and the EHB datasets. Our results exhibit prominent lateral heterogeneities in the study region. Distinct low-velocity anomalies are visible under the tectonically active regions, such as the Tienshan orogenic belt and western Kunlun Mountains, whereas pronounced high-velocity anomalies are imaged beneath the stable blocks, such as the Kazakh shield, the Junggar, Tarim, Qaidam, and Turpan-Hami basins, and the Tajik depression. Most strong earthquakes (Ms > 7.0) are mainly distributed along the transition zone of high to low velocity anomalies, suggesting a possible correlation between the strong earthquakes and the upper mantle structure. The fast directions of Pn anisotropy beneath the Tienshan orogenic belt are generally parallel to its striking orientation, whereas those beneath Pamir show a northward arc-shaped distribution. The Pn fast-velocity directions on the boundaries of the Kazakh shield and the Tarim and Junngar basins are approximately perpendicular to the strike of the Tienshan orogenic belt. By integrating with previous findings, our results suggest that the Tarim and Kazakh lithospheric materials could have underthrusted beneath the Tienshan orogenic belt that leads to the hot mantle material upwelling under the Tienshan orogenic belt, which is attributable to the Indo-Asian collision. These dynamic processes could play important roles in the Tienshan mountain building.

  5. Searching for Chips of Kuiper Belt Objects in Meteorites (United States)

    Zolensky, M. E.; Ohsumi, K.; Briani, G.; Gounelle, M.; Mikouchi, T.; Satake, W.; Kurihara, T.; Weisberg, M. K.; Le, L.


    The Nice model [1&2] describes a scenario whereby the Jovian planets experienced a violent reshuffling event approx.3:9 Ga the giant planets moved, existing small body reservoirs were depleted or eliminated, and new reservoirs were created in particular locations. The Nice model quantitatively explains the orbits of the Jovian planets and Neptune [1], the orbits of bodies in several different small body reservoirs in the outer solar system (e.g., Trojans of Jupiter [2], the Kuiper belt and scattered disk [3], the irregular satellites of the giant planets [4], and the late heavy bombardment on the terrestrial planets approx.3:9 Ga [5]. This model is unique in plausibly explaining all of these phenomena. One issue with the Nice model is that it predicts that transported Kuiper Belt Objects (KBOs) (things looking like D class asteroids) should predominate in the outer asteroid belt, but we know only about 10% of the objects in the outer main asteroid belt appear to be D-class objects [6]. However based upon collisional modeling, Bottke et al. [6] argue that more than 90% of the objects captured in the outer main belt could have been eliminated by impacts if they had been weakly-indurated objects. These disrupted objects should have left behind pieces in the ancient regoliths of other, presumably stronger asteroids. Thus, a derived prediction of the Nice model is that ancient regolith samples (regolith-bearing meteorites) should contain fragments of collisionally-destroyed Kuiper belt objects. In fact KBO pieces might be expected to be present in most ancient regolith- bearing meteorites [7&8].

  6. Fall Protection Characteristics of Safety Belts and Human Impact Tolerance


    HINO, Yasumichi; OHDO, Katsutoshi; Takahashi, Hiroki


    Abstract: Many fatal accidents due to falls from heights have occurred at construction sites not only in Japan but also in other countries. This study aims to determine the fall prevention performance of two types of safety belts: a body belt1 ), which has been used for more than 40 yr in the Japanese construction industry as a general type of safety equipment for fall accident prevention, and a full harness2, 3 ), which has been used in many other countries. To determine human tolerance for ...

  7. Bifurcation for Dynamical Systems of Planet-Belt Interaction


    Jiang, Ing-Guey; Yeh, Li-Chin


    The dynamical systems of planet-belt interaction are studied by the fixed-point analysis and the bifurcation of solutions on the parameter space is discussed. For most cases, our analytical and numerical results show that the locations of fixed points are determined by the parameters and these fixed points are either structurally stable or unstable. In addition to that, there are two special fixed points: the one on the inner edge of the belt is asymptotically stable and the one on the outer ...

  8. Fine Belt-Buckles of Walrus Ivory – also Made in Greenland

    DEFF Research Database (Denmark)

    Roesdahl, Else

    On the production of decorative artefacts in Norse Greenland - and new finds of walrus ivory belt buckles......On the production of decorative artefacts in Norse Greenland - and new finds of walrus ivory belt buckles...

  9. WISE Albedos for Tens of Thousands of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, Joseph R.; Mainzer, A. K.; Bauer, J.; Cutri, R.; Dailey, J.; Delbo, M.; Grav, T.; McMillan, R. S.; Mueller, M.; Walker, R.; Wright, E.; WISE Science Team, [No Value


    Using thermal IR data from the Wide-field Infrared Survey Explorer (WISE) mission we have calculated diameters for tens of thousands of previously known Main Belt asteroids. Using archival optical observations we have also determined albedos for each object. We present our results from this investig

  10. Resolving the Planetesimal Belt of HR 8799 with ALMA

    CERN Document Server

    Booth, Mark; Casassus, Simon; Hales, Antonio S; Dent, William R F; Faramaz, Virginie; Matrà, Luca; Barkats, Denis; Brahm, Rafael; Cuadra, Jorge


    The star HR 8799 hosts one of the largest known debris discs and at least four giant planets. Previous observations have found evidence for a warm belt within the orbits of the planets, a cold planetesimal belt beyond their orbits and a halo of small grains. With the infrared data, it is hard to distinguish the planetesimal belt emission from that of the grains in the halo. With this in mind, the system has been observed with ALMA in band 6 (1.34 mm) using a compact array format. These observations allow the inner edge of the planetesimal belt to be resolved for the first time. A radial distribution of dust grains is fitted to the data using an MCMC method. The disc is best fit by a broad ring between $145^{+12}_{-12}$ AU and $429^{+37}_{-32}$ AU at an inclination of $40^{+5}_{-6}${\\deg} and a position angle of $51^{+8}_{-8}${\\deg}. A disc edge at ~145 AU is too far out to be explained simply by interactions with planet b, requiring either a more complicated dynamical history or an extra planet beyond the orb...

  11. 1991 National campaign to increase safety belt usage.

    NARCIS (Netherlands)

    National Highway Traffic Safety Administration NHTSA


    The central theme of this paper is the national campaign of the USA to be conducted in 1991 and 1992, in order to reach the goal of 70 percent safety belt usage by 1992. Among other things, it is shown that visible enforcement of existing laws offers the greatest potential for achieving this goal. F

  12. Belt charging system for the 35 MV Vivitron accelerator

    International Nuclear Information System (INIS)

    A Van de Graaff belt charging system has been chosen for the Vivitron. Although classical in its principle and conservative in its design, it includes different new features that will be discussed in detail. The main electrical and mechanical characteristics are also reviewed together with the status of the project

  13. Radiation Belt Storm Probes (RBSP) Payload Safety Introduction Briefing (United States)

    Loftin, Chuck; Lampert, Dianna; Herrburger, Eric; Smith, Clay; Hill, Stuart; VonMehlem, Judi


    Mission of the Geospace Radiation Belt Storm Probes (RBSP) is: Gain s cientific understanding (to the point of predictability) of how populations of relativistic electrons and ions in space form or change in response to changes in solar activity and the solar wind.

  14. Chaos in Mean Motion Resonances of the Kuiper Belt

    CERN Document Server

    Franklin, Fred


    In this paper on mean motion resonances in the Kuiper belt we consider effects on resonant bodies captured in an earlier migration by determining levels of chaos as a function of eccentricity, e, at the most stable orbital configuration. We find the the maximum observed e's at resonance very closely correspond to orbits with Lyapunov times ~ 1000 orbital periods of Neptune--much the same number as applies in the asteroid belt with Neptune's period replaced by Jupiter's. The fact that this number caps the e's of markedly chaotic but still existing bodies, implies that the great majority of escapes at equal and larger e's have already occurred. Yet escapes must continue at some level if the small population in the outermost belt is to be maintained because typical lifetimes of bodies there are only ~ 1/10 of the solar system's age. A study of stability at resonance also reinforces the claim that the post-migration boundary of the inner Kuiper belt lies near 34 AU and that the primordial, or pre-migration, outer...

  15. Development of a new Global RAdiation Belt model: GRAB (United States)

    Sicard-Piet, Angelica; Lazaro, Didier; Maget, Vincent; Rolland, Guy; Ecoffet, Robert; Bourdarie, Sébastien; Boscher, Daniel; Standarovski, Denis


    The well known AP8 and AE8 NASA models are commonly used in the industry to specify the radiation belt environment. Unfortunately, there are some limitations in the use of these models, first due to the covered energy range, but also because in some regions of space, there are discrepancies between the predicted average values and the measurements. Therefore, our aim is to develop a radiation belt model, covering a large region of space and energy, from LEO altitudes to GEO and above, and from plasma to relativistic particles. The aim for the first version is to correct the AP8 and AE8 models where they are deficient or not defined. At geostationary, we developed ten years ago for electrons the IGE-2006 model which was proven to be more accurate than AE8, and used commonly in the industry, covering a broad energy range, from 1keV to 5MeV. From then, a proton model for geostationary orbit was also developed for material applications, followed by the OZONE model covering a narrower energy range but the whole outer electron belt, a SLOT model to asses average electron values for 2international partnership. This model will be called the GRAB model, as Global Radiation Belt model. We will present first beta version during this conference.

  16. Tectonics of the Tongbai-Dabie fold belt (United States)

    Wenpu, Ma

    The Qinling fold belt is the northernmost branch of the Paleozoic and Mesozoic Tethys in eastern Asia and contains all the inter-reacting records of the North China Block (NCB) and the South China Block (SCB). The Tongbai-Dabie fold belt is its eastern section. The Qinling belt was a collage of two orogens. The north Qinling is a late Paleozoic collision orogen, which started with Proterozoic rifting, transforming into active continental margin during the middle Ordovician. The intermitten ophiolite fragments indicate the existence of an oceanic crust at that time. The collision that occurred in the Devonian was an east-west diachronous process. The main suture zone is marked by ophiolitic melange extending nearly 500 km. The late Mesozoic molasse, volcano-plutonic activity and huge imbricate thrust system all respond to the further shortening of the crust and adjustment of the intracontinental strain. The south Qinling east of the Nanyang Basin is located to the south of Tongbai mountain. A pile of thick Sinian-Silurian volcanic and marine clastic deposits imply another marine incursion. Its history in south Shaanxi could continue to the Mesozoic. The flysch trough represented by Xinyang group may be the key area for revealing the relationship between north and south Qinling. The discussion in the paper is mainly focused on the nature and evolution of the Tongbai-Dabie fold belt.

  17. Effective Conveyor Belt Inspection for Improved Mining Productivity

    Energy Technology Data Exchange (ETDEWEB)

    Chris Fromme


    This document details progress on the project entitled ''Effective Conveyor Belt Inspection for Improved Mining Productivity'' during the period from November 15, 2004 to May 14, 2004. Highlights include fabrication of low-cost prototype hardware, acquisition of infrared thermal data, and initial design of a Smart-Camera based system.

  18. Uranium deposits of the Grants, New Mexico mineral belt (II)

    International Nuclear Information System (INIS)

    This is part of a study of the genesis of the U deposits of the Grants mineral belt. Enrichment of Mg in ore zones is frequently observed, with chlorite being a common product. Clay mineralogic studies argue for chlorite-illite-montmorillonite associations with ores. The methods include scanning electron microscopy, Eh-pH diagrams, activation analysis, and rare earth element studies

  19. Design study of flat belt CVT for electric vehicles (United States)

    Kumm, E. L.


    A continuously variable transmission (CVT) was studied, using a novel flat belt pulley arrangement which couples the high speed output shaft of an energy storage flywheel to the drive train of an electric vehicle. A specific CVT arrangement was recommended and its components were selected and sized, based on the design requirements of a 1700 KG vehicle. A design layout was prepared and engineering calculations made of component efficiencies and operating life. The transmission efficiency was calculated to be significantly over 90% with the expected vehicle operation. A design consistent with automotive practice for low future production costs was considered, together with maintainability. The technology advancements required to develop the flat belt CVT were identified and an estimate was made of how the size of the flat belt CVT scales to larger and smaller design output torques. The suitability of the flat belt CVT for alternate application to an electric vehicle powered by an electric motor without flywheel and to a hybrid electric vehicle powered by an electric motor with an internal combustion engine was studied.

  20. Resolving the planetesimal belt of HR 8799 with ALMA (United States)

    Booth, Mark; Jordán, Andrés; Casassus, Simon; Hales, Antonio S.; Dent, William R. F.; Faramaz, Virginie; Matrà, Luca; Barkats, Denis; Brahm, Rafael; Cuadra, Jorge


    The star HR 8799 hosts one of the largest known debris discs and at least four giant planets. Previous observations have found evidence for a warm belt within the orbits of the planets, a cold planetesimal belt beyond their orbits and a halo of small grains. With the infrared data, it is hard to distinguish the planetesimal belt emission from that of the grains in the halo. With this in mind, the system has been observed with ALMA in band 6 (1.34 mm) using a compact array format. These observations allow the inner edge of the planetesimal belt to be resolved for the first time. A radial distribution of dust grains is fitted to the data using an MCMC method. The disc is best fitted by a broad ring between 145^{+12}_{-12} au and 429^{+37}_{-32} au at an inclination of 40^{+5}_{-6}° and a position angle of 51^{+8}_{-8}°. A disc edge at ˜145 au is too far out to be explained simply by interactions with planet b, requiring either a more complicated dynamical history or an extra planet beyond the orbit of planet b.

  1. Structural appraisal of the Gadag schist belt from gravity investigations

    Indian Academy of Sciences (India)

    G Ramadass; D Himabindu; N Srinivasulu


    Semi-detailed gravity investigations were carried out over an area of approximately 2750 sq km with maximum N-S and E-W extents of 55 and 50km respectively in the Gadag region in the Dharwar craton with a view to obtain a clearer perception of the structural configuration of the region. From qualitative analysis of the gravity data, several tectonic features are inferred: the high density Gadag schist belt is characterized by a gravity high and occurs in two discontinuous segments — the main N-S trending segment, and its thinner NW-SE trending extension, the two separated by a NE-SW trending deep seated fault. While the N-S trend of the Gadag schist belt is bounded on its east by the NW-SE trending Chitradurga thrust fault and on its west by another major NNW-SSE trending fault, the NW-SE extension is likewise bounded by two other NW-SE major faults. Quantitative evaluation from forward modeling/inversion of five profiles in the region, assuming a density contrast of 0.29 gm/cc of the anomalous schistose body with the gneissic host rocks indicated a synclinal structure plunging to the southeast along its axis for the Gadag schist belt. The maximum width and depth from surface of the schist belt are 22km and 5.6km respectively.

  2. Influence of the Gould Belt on Interstellar Extinction

    CERN Document Server

    Gontcharov, George


    A new analytical 3D model of interstellar extinction within 500 pc of the Sun as a function of the Galactic spherical coordinates is suggested. This model is physically more justified than the widely used Arenou model, since it takes into account the presence of absorbing matter both in the layer along the equatorial Galactic plane and in the Gould Belt. The extinction in the equatorial layer varies as the sine of the Galactic longitude and in the Gould Belt as the sine of twice the longitude in the Belt plane. The extinction across the layers varies according to a barometric law. It has been found that the absorbing layers intersect at an angle of 17 deg and that the Sun is located near the axial plane of the absorbing layer of the Gould Belt and is probably several parsecs below the axial plane of the equatorial absorbing layer but above the Galactic plane. The model has been tested using the extinction of real stars from three catalogs.

  3. Global Storm-Time Depletion of the Outer Electron Belt (United States)

    Ukhorskiy, A. Y.; Sitnov, M. I.; Millan, R. M.; Kress, B. T.; Fennell, J. F.


    The outer radiation belt consists of relativistic (≳0.5 MeV) electrons trapped on closed trajectories around Earth where its magnetic field is nearly dipolar. During increased geomagnetic activity electron intensities in the belt can vary by orders of magnitude at different spatial and temporal scale. The main phase of geomagnetic storms often produces deep depletions of electron intensities over broad regions of the outer belt. Previous studies identified three possible processes that can contribute to the depletions: fully adiabatic inflation of electron drift orbits caused the ring current growth, electron loss into the atmosphere due to pitch-angle scattering by plasma waves (e.g., EMIC and whistler waves), and electron escape through the magnetopause boundary. In this paper we investigate the relative importance of the magnetopause losses to the rapid depletion of the outer belt observed at the Van Allen Probes spacecraft during the main phase of March 17, 2013 storm. The intensities of > 1 MeV electrons were depleted by more that an order of magnitude over the entire radial extent of the belt in less than 6 hours after the sudden storm commencement. For the analysis we used three-dimensional test-particle simulations of global evolution of the outer belt in the Tsyganenko-Sitnov (TS07D) magnetic field model with the inductive electric field. The comparison of the simulation results with electron measurements from the MagEIS experiment shows that the magnetopause losses in the model accounts for most of the observed depletion. The individual electron motion the process is non-adiabatic; the third invariant is violated by global variations of the inner magnetospheric fields caused by the magnetopause compressions and the buildup of ring current, while the second invariant is violated at drift orbit bifurcations. The analysis shows that the observed deep depletion of radiation belt intensities is enabled by the change in the global configuration of magnetic

  4. Flexible electrode belt for EIT using nanofiber web dry electrodes

    International Nuclear Information System (INIS)

    Efficient connection of multiple electrodes to the body for impedance measurement and voltage monitoring applications is of critical importance to measurement quality and practicality. Electrical impedance tomography (EIT) experiments have generally required a cumbersome procedure to attach the multiple electrodes needed in EIT. Once placed, these electrodes must then maintain good contact with the skin during measurements that may last several hours. There is usually also the need to manage the wires that run between the electrodes and the EIT system. These problems become more severe as the number of electrodes increases, and may limit the practicality and portability of this imaging method. There have been several trials describing human–electrode interfaces using configurations such as electrode belts, helmets or rings. In this paper, we describe an electrode belt we developed for long-term EIT monitoring of human lung ventilation. The belt included 16 embossed electrodes that were designed to make good contact with the skin. The electrodes were fabricated using an Ag-plated PVDF nanofiber web and metallic threads. A large contact area and padding were used behind each electrode to improve subject comfort and reduce contact impedances. The electrodes were incorporated, equally spaced, into an elasticated fabric belt. We tested the electrode belt in conjunction with the KHU Mark1 multi-frequency EIT system, and demonstrate time-difference images of phantoms and human subjects during normal breathing and running. We found that the Ag-plated PVDF nanofiber web electrodes were suitable for long-term measurement because of their flexibility and durability. Moreover, the contact impedance and stability of the Ag-plated PVDF nanofiber web electrodes were found to be comparable to similarly tested Ag/AgCl electrodes. (paper)

  5. Solar Modulation of Inner Trapped Belt Radiation Dose Rate (United States)

    Diaz, Abel


    The two steady sources of radiation in low Earth orbit are the inner trapped-belt and galactic cosmic radiation (GCR), which present a very significant hazard to the astronauts and flight equipment electronics. The fluxes of GCR and inner trapped-belt particles at a fixed altitude are modulated by solar activity. They decrease with increasing solar activity in general. The mechanism of these two sources of radiation are, however, very different. In this project we shall be concerned with modeling the inner trapped-belt protons. The existing trapped-belt models, namely AP-8 is based on data acquired prior to 1970 during solar cycle 20 with relatively low solar flux. These models describe the environment at solar minimum and solar maximum only. Cycles 21 and 22 were much larger, but no valid radiation model exists for such large values. Moreover, the existing models like AP-8, CRRESPRO, and GOST describe the flux to an accuracy of a factor of two to five. There is clear need to accurately predict radiation exposure of astronauts and equipment at all times between the solar minimum and solar maximum, not only on the short duration Space Shuttle flights, but also the longer term stay onboard the International Space Station. In our approach we are taking into account some important parameters, which are responsible for energy losses of protons within the belts. These energy losses are primarily to electrons and by collisions to atmospheric nuclei. Accordingly the atmospheric density dependence at a certain altitude during a specific solar activity is an important parameter that needs to be accurately incorporated into a realistic model. We are involved in developing such a model, which would enable us to predict the radiation exposure for all occasions.

  6. Leaching of S, Cu, and Fe from disseminated Ni-(Fe)-(Cu) sulphide ore during serpentinization of dunite host rocks at Mount Keith, Agnew-Wiluna belt, Western Australia (United States)

    Gole, Martin J.


    Komatiite-hosted disseminated Ni sulphide deposits in the Agnew-Wiluna greenstone belt occur both above and below the olivine isograd that was imposed on the greenstone sequence during the M2 metamorphic/deformation event. Deposits in the northern and central part of the belt and that are located below the isograd (Mount Keith, Honeymoon Well and West Jordan) have complex sulphide mineralogy and strongly zoned sulphide assemblages. These range from least-altered assemblages of pentlandite-pyrrhotite-chalcopyrite±pyrite to altered assemblages of pentlandite±chalcopyrite, pentlandite-heazlewoodite (or millerite), heazlewoodite (or millerite), and rarely to heazlewoodite-native Ni. Deposits to the south and that are above of the olivine isograd (Six Mile, Goliath North) are dominated by less complex magmatic assemblages with a lower proportion of weakly altered pentlandite±chalcopyrite assemblages. More altered assemblages are uncommon in these deposits and occur as isolated patches around the periphery of the deposits. The sulphide zonation is reflected by whole-rock reductions in S, Cu, Fe and Zn, whereas Ni, Pt and Pd and, with some exceptions, Co are conservative. The leaching of S, Cu, Fe and Zn from sulphide assemblages and the whole rock was initiated by highly reduced conditions that were produced during low fluid/rock ratio serpentinization. Consumption of H2O resulted in Cl, a component of the fluid, being concentrated sufficiently to stabilise iowaite as part of lizardite-rich assemblages. Once the rate of olivine hydration reactions declined and during and after expansion and associated fracturing of the ultramafic sequence allowed higher fluid access, a more fluid-dominated environment formed and new carbonate-bearing fluid gained access to varying extents to the ultramafic rock sequence. This drove Cl from iowaite (to form pyroaurite) and caused the sulphide assemblages to be altered from the original magmatic assemblages and compositions to those



    Kanyi, Peter M.; Baharanyi, Ntam; Ngandu, Mudiayi Sylvain; Zabawa, Robert


    This study assessed homeownership and how it is affected by race, residency in or out of Alabama Black Belt, family status, poverty and other variables. All variables showed significant relationship to Alabama homeownership with single-parenthood showing a negative impact on White homeownership but insignificant to Black homeownership in the region.

  8. Large enhancement of highly energetic electrons in the outer radiation belt and its transport into the inner radiation belt inferred from MDS-1 satellite observations (United States)

    Obara, T.; Matsumoto, H.


    We have examined a large increase of relativistic electrons in the outer radiation belt and its penetration into the inner radiation belt over slot region using the MDS-1 satellite observations. Result of analyses demonstrates that a large increase took place in the spring and autumn seasons, and we have newly confirmed that the penetration of outer belt electrons to the inner radiation zone took place during the big magnetic storms by examining a pitch angle distribution of the penetrating electrons.

  9. Comparison of two pelvic positioning belt configurations in a pediatric wheelchair. (United States)

    Cimolin, Veronica; Avellis, Martino; Piccinini, Luigi; Corbetta, Claudio; Cazzaniga, Andrea; Turconi, Anna Carla; Galli, Manuela


    Maintenance of stability for children in a wheelchair, particularly for those with spasticity, can be achieved through external stabilization components, such as pelvic positioning belts. Different kinds of pelvic belts exist on the market and one of the main characteristics is the different number of attachment points between the seat and the belt. As literature on this topic is limited to qualitative assessments, this study compared quantitatively 4-point versus 2-point pelvic positioning belts for the trunk fixation in 20 young patients with spasticity. Our data showed that 70% of the children required the use of pelvic belts on wheelchairs for stability and a better stability was observed with the 4-point belts than compared to the 2-point. Data generally showed in fact a higher percent of variation in terms of trunk flexion angleand knee joint angle with the 2-point belt than the 4-point belt, indicating increased submarining with the 2-point belt during sitting maintenance if compared to the 4-point belt (p < 0.05). According to our results, the 4-point belts seem to be the most effective configuration for patient stabilization, suggesting that its use prevents the thigh from submarining. PMID:24620707

  10. Intrusive rocks and plutonic belts of southeastern Alaska, U.S.A. (United States)

    Brew, David A.; Morrell, Robert P.


    About 30 percent of the 175,000-km2 area of southeastern Alaska is underlain by intrusive igneous rocks. Compilation of available information on the distribution, composition, and ages of these rocks indicates the presence of six major and six minor plutonic belts. From west to east, the major belts are: the Fairweather-Baranof belt of early to mid-Tertiary granodiorite; the Muir-Chichagof belt of mid-Cretaceous tonalite and granodiorite; the Admiralty-Revillagigedo belt of porphyritic granodiorite, quartz diorite, and diorite of probable Cretaceous age; the Klukwan-Duke belt of concentrically zoned or Alaskan-type ultramafic-mafic plutons of mid-Cretaceous age within the Admiralty-Revillagigedo belt; the Coast Plutonic Complex sill belt of tonalite of unknown, but perhaps mid-Cretaceous, age; and the Coast Plutonic Complex belt I of early to mid-Tertiary granodiorite and quartz monzonite. The minor belts are distributed as follows: the Glacier Bay belt of Cretaceous and(or) Tertiary granodiorite, tonalite, and quartz diorite lies within the Fair-weather-Baranof belt; layered gabbro complexes of inferred mid-Tertiary age lie within and are probably related to the Fairweather-Baranof belt; the Chilkat-Chichagof belt of Jurassic granodiorite and tonalite lies within the Muir-Chichagof belt; the Sitkoh Bay alkaline, the Kendrick Bay pyroxenite to quartz monzonite, and the Annette and Cape Fox trondhjemite plutons, all interpreted to be of Ordovician(?) age, together form the crude southern southeastern Alaska belt within the Muir-Chichagof belt; the Kuiu-Etolin mid-Tertiary belt of volcanic and plutonic rocks extends from the Muir-Chichagof belt eastward into the Admiralty-Revillagigedo belt; and the Behm Canal belt of mid- to late Tertiary granite lies within and next to Coast Plutonic Complex belt II. In addition, scattered mafic-ultramafic bodies occur within the Fairweather-Baranof, Muir-Chichagof, and Coast Plutonic Complex belts I and II. Palinspastic

  11. Dynamics of the earth's radiation belts and inner magnetosphere (geophysical monograph series)

    CERN Document Server


    Dynamics of the Earth's Radiation Belts and Inner Magnetosphere draws together current knowledge of the radiation belts prior to the launch of Radiation Belt Storm Probes (RPSP) and other imminent space missions, making this volume timely and unique. The volume will serve as a useful benchmark at this exciting and pivotal period in radiation belt research in advance of the new discoveries that the RPSP mission will surely bring. Highlights include the following: a review of the current state of the art of radiation belt science; a complete and up-to-date account of the wave-particle interactions that control the dynamical acceleration and loss processes of particles in the Earth's radiation belts and inner magnetosphere; a discussion emphasizing the importance of the cross-energy coupling of the particle populations of the radiation belts, ring current, and plasmasphere in controlling the dynamics of the inner magnetosphe...

  12. The Debiased Kuiper Belt: Our Solar System as a Debris Disk

    CERN Document Server

    Lawler, S M


    The dust measured in debris disks traces the position of planetesimal belts. In our Solar System, we are also able to measure the largest planetesimals directly and can extrapolate down to make an estimate of the dust. The zodiacal dust from the asteroid belt is better constrained than the only rudimentary measurements of Kuiper belt dust. Dust models will thus be based on the current orbital distribution of the larger bodies which provide the collisional source. The orbital distribution of many Kuiper belt objects is strongly affected by dynamical interactions with Neptune, and the structure cannot be understood without taking this into account. We present the debiased Kuiper belt as measured by the Canada-France Ecliptic Plane Survey (CFEPS). This model includes the absolute populations for objects with diameters >100 km, measured orbital distributions, and size distributions of the components of the Kuiper belt: the classical belt (hot, stirred, and kernel components), the scattering disk, the detached obj...


    Directory of Open Access Journals (Sweden)

    Florin Adrian PĂUN


    Full Text Available Conveyor belts are used for a long period of time in the industry branches where potentially explosive atmospheres could occur. Dangerous phenomena which can be in direct connection with the use of conveyor belts are the ones regarding: - sparks influence over the coating layer and/or resistance internal structure of the stopped conveyor belt; - propagation of a flame along the length of a conveyor belt that was exposed to a energy source relative high like a fire or due to blockage of a conveyor belt as a result of the driving mechanism still operating, that generate a local heating of the conveyor belt in contact with the driving drum, rollers or any other heating source generated by friction. Determining the safety parameters characteristic of the conveyor belts by employing test methods allows assessment of the safety level as well as certification of their explosion protection quality when used in environments with explosion danger.

  14. Controls on accretion of flysch and melange belts at convergent margins: evidence from the Chugach Bay thrust and Iceworm melange, Chugach accretionary wedge, Alaska (United States)

    Kusky, T.M.; Bradley, D.C.; Haeussler, P.J.; Karl, S.


    Controls on accretion of flysch and melange terranes at convergent margins are poorly understood. Southern Alaska's Chugach terrane forms the outboard accretionary margin of the Wrangellia composite terrane, and consists of two major lithotectonic units, including Triassic-Cretaceous melange of the McHugh Complex and Late Cretaceous flysch of the Valdez Group. The contact between the McHugh Complex and the Valdez Group on the Kenai Peninsula is a tectonic boundary between chaotically deformed melange of argillite, chert, greenstone, and graywacke of the McHugh Complex and a less chaotically deformed melange of argillite and graywacke of the Valdez Group. We assign the latter to a new, informal unit of formational rank, the Iceworm melange, and interpret it as a contractional fault zone (Chugach Bay thrust) along which the Valdez Group was emplaced beneath the McHugh Complex. The McHugh Complex had already been deformed and metamorphosed to prehnite-pumpellyite facies prior to formation of the Iceworm melange. The Chugach Bay thrust formed between 75 and 55 Ma, as shown by Campanian-Maastrichtian depositional ages of the Valdez Group, and fault-related fabrics in the Iceworm melange that are cut by Paleocene dikes. Motion along the Chugach Bay thrust thus followed Middle to Late Cretaceous collision (circa 90-100 Ma) of the Wrangellia composite terrane with North America. Collision related uplift and erosion of mountains in British Columbia formed a submarine fan on the Farallon plate, and we suggest that attempted subduction of this fan dramatically changed the subduction/accretion style within the Chugach accretionary wedge. We propose a model in which subduction of thinly sedimented plates concentrates shear strains in a narrow zone, generating melanges like the McHugh in accretionary complexes. Subduction of thickly sedimented plates allows wider distribution of shear strains to accommodate plate convergence, generating a more coherent accretionary style

  15. Self-reported safety belt use among emergency department patients in Boston, Massachusetts

    Directory of Open Access Journals (Sweden)

    Mitchell Patricia


    Full Text Available Abstract Background Safety belt use is 80% nationally, yet only 63% in Massachusetts. Safety belt use among potentially at-risk groups in Boston is unknown. We sought to assess the prevalence and correlates of belt non-use among emergency department (ED patients in Boston. Methods A cross-sectional survey with systematic sampling was conducted on non-urgent ED patients age ≥18. A closed-ended survey was administered by interview. Safety belt use was defined via two methods: a single-item and a multiple-item measure of safety belt use. Each was scored using a 5-point frequency scale. Responses were used to categorize safety belt use as 'always' or less than 'always'. Outcome for multivariate logistic regression analysis was safety belt use less than 'always'. Results Of 478 patients approached, 381 (80% participated. Participants were 48% female, 48% African-American, 40% White, median age 39. Among participants, 250 (66% had been in a car crash; 234 (61% had a valid driver's license, and 42 (11% had been ticketed for belt non-use. Using two different survey measures, a single-item and a multiple-item measure, safety belt use 'always' was 51% and 36% respectively. According to separate regression models, factors associated with belt non-use included male gender, alcohol consumption >5 drinks in one episode, riding with others that drink and drive, ever receiving a citation for belt non-use, believing that safety belt use is 'uncomfortable', and that 'I just forget', while 'It's my usual habit' was protective. Conclusion ED patients at an urban hospital in Boston have considerably lower self-reported safety belt use than state or national estimates. An ED-based intervention to increase safety belt use among this hard-to-reach population warrants consideration.

  16. Reducing the consequences of reactor accidents with a green belt

    International Nuclear Information System (INIS)

    Considerable attention is being paid to reducing the consequences of low-probability accidents in nuclear power plants. A scheme based on the pollution absorption properties of trees is proposed to reduce early and continued mortalities among the general public due to an accident in a nuclear power plant. The consequences of a hypothetical case in which a large, cold, ground-level release of radionuclides into the atmosphere takes place have been analyzed in the absence and in the presence of a green belt (rows of trees). The results show that in the presence of a suitably designed green belt around a nuclear power plant, the consequences in terms of early and continued mortality as well as an interdiction area, involving relocation of population and supply of food stuff from an uncontaminated region, can be reduced by orders of magnitude. This could also help in substantially reducing the magnitude of emergency preparedness in the public domain

  17. Tribological Properties of Metal V-Belt Type CVT Lubricant

    Directory of Open Access Journals (Sweden)

    Keiichi Narita


    Full Text Available The priority for lubricant performance for metal V-belt-type CVT (B-CVTFs should be the improvement of transmittable torque capacity between the belt and pulley plus excellent antishudder properties for lockup clutch used in B-CVTs. This study intends to investigate the effect of lubricant additives for improving these performances of B-CVTs. In addition, surface analysis techniques were utilized to gain a novel insight into the chemical composites and morphology of the tribofilms. As a result, it is vital for greater torque capacity to give higher boundary friction coefficient between the metal contacting interfaces, and the process of boundary lubricant film formation derived from antiwear additives used in B-CVTFs strongly impacts on the torque capacity. Moreover, it is found that a sort of lubricant formulation gave an excellent antishudder performance for wet clutch with keeping higher friction coefficient between the metals, which would result in improving the performance of B-CVTs.

  18. Modeling The Dynamics Of Outer Radiation Belt Electrons

    CERN Document Server

    Naehr, S M


    A computer model has been built to simulate the dynamic evolution of relativistic electrons in the outer radiation belt. The model calculates changes in electron flux due to three mechanisms: (1) fully-adiabatic response of electrons to variations in the magnetic field, (2) time-dependent radial diffusion, parameterized by overall magnetospheric activity, and (3) penetration of new particles into the model via a time-dependent outer boundary condition. Data from Los Alamos geosynchronous satellites, the CRRESELE statistical electron flux model, the Kp index, and the Toffoletto-Hill-Ding magnetic field model are all used to provide realistic, time-dependent inputs to the model. To evaluate the model, a simulation of the radiation belts during the November 3–12, 1993 magnetic storm was generated. Comparison of results to Global Positioning System (GPS) radiation dosimeter data indicates that the model can accurately predict storm-time flux variations for electrons with energies less than 600 keV. Mode...

  19. Operational experiences with belt rollers for bulk conveying

    Energy Technology Data Exchange (ETDEWEB)

    Dietl, W.


    Explains the design of belt rollers produced by TAKRAF for conveyor belts 0.3 m to 3.0 m wide. Light, medium and heavy-duty rollers are manufactured according to a common basic design; the roller diameters range from 63 mm to 245 mm. Major parameters of rollers are discussed, the theoretical roller service life is calculated. Operational conditions which must be observed in order to obtain the theoretical service life in operation are listed. The principle design of the roller is demonstrated in a scheme, focusing on the axial labyrinth seal. Impact forces on rollers at conveyor feeding stations are analyzed. Tests have been carried out using rollers provided with shock absorbing rubber elements compensating the impact load of the bulk, which, however, did not prove to be advantageous. Conclusions on the design of heavy duty rollers to be used at feeding stations are further outlined. (3 refs.) (In German)

  20. Coralling a distant planet with extreme resonant Kuiper belt objects

    CERN Document Server

    Malhotra, Renu; Wang, Xianyu


    The four longest period Kuiper belt objects have orbital periods close to small integer ratios with each other. A hypothetical planet with orbital period $\\sim$17,117 years, semimajor axis $\\sim$665 AU, would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity and the mass of such a planet, as well as its current location in its orbital path.

  1. The Analysis of Insects Population on Fields in Forest Belts


    Gribust Irina Romuvaldovna


    The introduction into the agricultural and ecological system of multifunctional forest belts contributes to the formation of a qualitatively new environment, and, as a consequence, to the transformation of insects populations. Change of the faunal diversity in transformed agro-ecosystems and identification of entomofauna characteristics by a number of biotic indices, which undergo cumulative impact of organized farm ecosystem components, have not been sufficiently studied. This question is th...

  2. The benefit of seat belt legislation in the United Kingdom.


    M. McCarthy


    Legislation for compulsory wearing of seat belts by car drivers and front seat passengers has been acclaimed as a major public health advance. Reports from other countries, and two recent evaluative studies in the United Kingdom, have suggested that legislation reduces both deaths and injuries. To assess the effect of the UK law 5 years after its implementation, trends in routine data for 1976-1987 have been reviewed. There were two sources of data: mortality statistics, published by the Offi...

  3. Dynamical behavior of whistler mode waves in the radiation belts

    Czech Academy of Sciences Publication Activity Database

    Santolík, Ondřej; Hospodarsky, G. B.; Kurth, W. S.; Averkamp, T. F.; Kletzing, C. A.

    Prague: International Union of Geodesy and Geophysics, 2015. IUGG-1762. [Earth and Environmental Sciences for Future Generations. General Assembly of International Union of Geodesy and Geophysics /26./. 22.06.2015-02.07.2015, Prague] Institutional support: RVO:68378289 Keywords : chorus and plasmaspheric hiss * Van Allen radiation belts Subject RIV: DG - Athmosphere Sciences, Meteorology

  4. Radiation Belt Electron Dynamics Driven by Large-Amplitude Whistlers (United States)

    Khazanov, G. V.; Tel'nikhin, A. A.; Kronberg, T. K.


    Acceleration of radiation belt electrons driven by oblique large-amplitude whistler waves is studied. We show analytically and numerically that this is a stochastic process; the intensity of which depends on the wave power modified by Bessel functions. The type of this dependence is determined by the character of the nonlinear interaction due to coupling between action and phase. The results show that physically significant quantities have a relatively weak dependence on the wave power.

  5. Future aerosol reductions and widening of the northern tropical belt (United States)

    Allen, Robert J.; Ajoku, Osinachi


    Observations show that the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large-scale atmospheric circulation. Although part of this signal is related to natural climate variability, studies have identified an externally forced contribution primarily associated with greenhouse gases (GHGs) and stratospheric ozone loss. Here we show that the increase in aerosols over the twentieth century has led to contraction of the northern tropical belt, thereby offsetting part of the widening associated with the increase in GHGs. Over the 21st century, however, when aerosol emissions are projected to decrease, the effects of aerosols and GHGs reinforce one another, both contributing to widening of the northern tropical belt. Models that have larger aerosol forcing, by including aerosol indirect effects on cloud albedo and lifetime, yield significantly larger Northern Hemisphere (NH) tropical widening than models with direct aerosol effects only. More targeted simulations show that future reductions in aerosols can drive NH tropical widening as large as greenhouse gases, and idealized simulations show the importance of NH midlatitude aerosol forcing. Mechanistically, the 21st century reduction in aerosols peaks near 40°N, which results in a corresponding maximum increase in surface solar radiation, NH midlatitude tropospheric warming amplification, and a poleward shift in the latitude of maximum baroclinicity, implying a corresponding shift in atmospheric circulation. If models with aerosol indirect effects better represent the real world, then future aerosol changes are likely to be an important -- if not dominant -- driver of NH tropical belt widening.

  6. An easy non-invasive X-ray diffraction method to determine the composition of Na-pyroxenes from high-density ;greenstone' implements. (United States)

    Giustetto, Roberto; Chiari, Giacomo; Compagnoni, Roberto


    A large number of polished stone implements from Palaeolithic to Bronze Age sites of Northern Italy and Southern France are made of high-pressure (HP) metamorphic rocks (eclogite and related rocks), mainly consisting of Na-pyroxene (jadeite to omphacite) from the metamorphic belt of the Western Alps. The standard archaeometric study of prehistoric stone implements follows a procedure that is invasive, expensive and time-consuming. Since Na-pyroxenes may show a large compositional range, a thorough study of the variations affecting the dhkl values, obtained by X-ray diffraction, of three selected reflections as a function of different chemical composition was carried out, in order to determine the chemistry of Na-pyroxene isomorphic mixtures and roughly evaluate their relative amounts. These reflections (\\bar221, 310, 002) are sharp, intense and sensitive to the variation of pyroxene chemical composition. Using such dhkl values measured on pyroxenes of known chemistry, a Ca-pyroxene(Di)-jadeite(Jd)-aegirine(Ae) compositional diagram was constructed, from which the composition of an unknown pyroxene can be estimated within an error of about 5%. When the size of the object is relatively small and a flat polished surface is present, the proposed analytical procedure becomes totally non-invasive. The data obtained shed light on the provenance sources of such implements and the prehistoric trade routes. PMID:18156681

  7. A photometric search for active Main Belt asteroids

    CERN Document Server

    Cikota, S; Cikota, A; Morales, N; Tancredi, G


    It is well known that some Main Belt asteroids show comet-like features. A representative example is the first known Main Belt comet 133P/(7968) Elst-Pizarro. If the mechanisms causing this activity are too weak to develop visually evident comae or tails, the objects stay unnoticed. We are presenting a novel way to search for active asteroids, based on looking for objects with deviations from their expected brightnesses in a database. Just by using the MPCAT-OBS Observation Archive we have found five new candidate objects that possibly show a type of comet-like activity, and the already known Main Belt comet 133P/(7968) Elst-Pizarro. Four of the new candidates, (315) Constantia, (1026) Ingrid, (3646) Aduatiques, and (24684) 1990 EU4, show brightness deviations independent of the object's heliocentric distance, while (35101) 1991 PL16 shows deviations dependent on its heliocentric distance, which could be an indication of a thermal triggered mechanism. The method could be implemented in future sky survey progr...

  8. An Experimental Concept for Probing Nonlinear Radiation Belt Physics (United States)

    Amatucci, Bill; Ganguli, Guru; Crabtree, Chris; Mithaiwala, Manish; Siefring, Carl; Tejero, Erik


    The SMART sounding rocket is designed to probe the nonlinear response of a known ionospheric stimulus. High-speed neutral barium atoms generated by a shaped charge explosion perpendicular to the magnetic field in the ionosphere form a ring velocity distribution of photo-ionized Ba+ that will generate lower hybrid waves. Induced nonlinear scattering of lower hybrid waves into whistler/magnetosonic waves has been theoretically predicted, confirmed by simulations, and observed in the lab. The effects of nonlinear scattering on wave evolution and whistler escape to the radiation belts have been studied and observable signatures quantified. The fraction of the neutral atom kinetic energy converted into waves is estimated at 10-12%. SMART will carry a Ba release module and an instrumented daughter section with vector wave magnetic and electric field sensors, Langmuir probes and energetic particle detectors to determine wave spectra in the source region and detect precipitated particles. The Van Allen Probes can detect the propagation of the scattered whistlers and their effects in the radiation belts. By measuring the radiation belt whistler energy density, SMART will confirm the nonlinear scattering process and the connection to weak turbulence. Supported by the Naval Research Laboratory Base Funds.

  9. Modeling of the outer electron belt during magnetic storms

    International Nuclear Information System (INIS)

    The flux dropout of relativistic electrons in the earth's outer radiation belt, during the main phase of the 26 March 1995 magnetic storm is examined. Outer belt measurements by the Radiation Environment Monitor, REM aboard the STRV-1b satellite are presented to characterize this dropout. In order to simulate the dynamics of the electron belt during the storm main phase a particle tracing code was developed which allows to trace the trajectories of equatorially mirroring electrons in a dynamic magnetospheric electromagnetic field. Two simulations were performed in a non-stationary magnetic field, one taking only the induced electric field into account (fully adiabatic motion), and one with an additional non-stationary convection electric field. The simulations show, that adiabatic deceleration can produce the observed count rate decrease and also the observed inward motion of the count rate peak. The convection electric field causes diffusion, which can take particles from low L values out to the magnetopause and contribute to an additional loss of particles, which is suggested by the observations

  10. Structural setting of the Apennine-Maghrebian thrust belt

    Institute of Scientific and Technical Information of China (English)

    PieroElter; MarioGrasso; MaurizioParotto; LivioVezzani


    The Apennine-Maghrebian fold-and-thrust belt devel-oped from the latest Cretaceous to Early Pleistocene at the subduction-collisional boundary between the Euro-pean and the westward-subducted Ionian and Adria plates. Large parts of the Mesozoic oceanic lithosphere were subducted during an Alpine phase from the Late Cretaceous to Middle Eocene. The chain developed through the deformation of major paleogeographic internal domains (tectono-sedimentary sequences of the Ligurian-Piedmont Ocean) and external domains (sedi-mentary sequences derived from the deformation of the continental Adria-African passive mareinL The continu-ity of the Apennine chain is abruptly interrupted in the Calabrian Arc by the extensive klippe of Kabylo-Calabrian crystalline exotic terranes, derived from deformation of the European passive margin.Major complexities (sharp deflections in the arcuate configuration of the thrust belt, out-of-sequence propagation of the thrusts) are referred to contrasting rheology and differential buoyancy of the subducted lithosphere (transitional from conti-nental to oceanic) and consequent differential roll-back of the Adria plate margin, and to competence contrasts in the Mesozoic stratigraphic sequences,where multiple décollement horizons at different stratigraphic levels may have favored significant differential shortening.From the Late Miocene, the geometry of the thrust belt was strongly modified by extensional fault-ing, volcanic activity, crustal thinning and formation of oceanic crust correlated with the development of the Tyrrhenian Basin.

  11. Establishing different size distributions in the asteroid belt (United States)

    Jacobson, Seth A.; Morbidelli, Alessandro


    While gas is present in the protoplanetary disk, aerodynamic drag circularizes, equatorializes and shrinks planetesimal orbits. The strength of this effect is size-dependent effecting smaller planetesimals more severely. During planet formation debris from giant impacts amongst the growing terrestrial embryos can be transported to the asteroid belt via scattering events and secular resonances. The effectiveness of this transport is strongly size dependent due to the aforementioned gas drag. Thus transported debris in the asteroid belt can have a strong size sorting. Further processing due to collisions and YORP-induced rotational fission during the lifetime of the solar system must be taken into account before a model population of debris can be compared to suspected planetary debris in the asteroid belt, such as the A-type asteroids. Furthermore, scenarios such as the Grand Tack may establish size distributions since they predict that S-type asteroids are transported from an inner planetesimal disk while C-type asteroids are transporeted from an outer planetesimal disk.

  12. Diagnosis of seat belt injury using spiral CT

    International Nuclear Information System (INIS)

    Seat belt injury (s.b.i.) arises from not properly applied seat belts in case of car accidents. The importance of spiral CT for the diagnosis of s.b.i., especially of hidden traumatic lesions, will be demonstrated. Our experience includes 9 children in the age of 4 to 13 years suffering from life-threatening s.b.i. After life-saving treatment we took a spiral CT (Somatom plus S): First spiral CT, 10 mm slice thickness, without contrast medium (c.m.) and second spiral CT, 5 mm slice thickness, start delay 35-45 s after a large volume of c.m. Of these, 8 of 9 children survived. Besides bruising signs, head injuries, and knee point lesions in 4 of 9 cases, a combination of uptured duodenum, ruptured liver or spleen, and chance fractures of the spine was found which is typical for s.b.i. In the remaining 5 cases, two of the lesions were combined. Rupture of the small bowel was manifested mainly as the discrete finding of free air or inhomogeneous ascites with a high density (bowel contents mixed with blood). Not only the emergency doctor but also the radiologist should take into account the complexity of seat belt injuries. Spiral CT is the imaging method of choice in the case of polytraumatic children. (orig.)

  13. Tool Belts: Latitudinal-Belt Predictions for the Persistence of Landscapes (United States)

    Willenbring, Jane; Brocard, Gilles


    The ability of rivers to cut through rock and re-establish equilibrium sets the pace of landscape response to uplift. Because of associations between tectonics, erosion, and weathering, high rates of rock uplift may initiate a cascade of processes that are linked to high rates of weathering and eventually sequestration of CO2 over geologic timescales. How long does it take to completely change the topographic form after uplift and where on Earth do relict landscapes persist despite uplift? Large expanses of subdued landscapes are common at high elevation in mountain ranges. Preservation of subdued fragments amongst steeply dissected regions can therefore be a simple matter of chance, reflecting the time it takes for dissection to remove any remaining parcel of the pre-existing topography after a tectonic perturbation. Some of these relicts may, however, possess characteristics - often a product of the climate - that make them intrinsically resistant to dissection. One common mode of conversion of a subdued landscape into a deeply dissected one is the propagation of upstream-migrating erosion waves that transmit the signal of uplift and base level lowering across entire landscapes. Following a shift in tectonic forcing, the Earth's surface progressively adjusts its topographic form over millions of years, seeking to re-establish equilibrium with the new forcing. Here, we show that a high degree of weathering leading to smaller average soil grains at the surface hinders the capacity of rivers to incise. We show that globally, rates of cosmogenic nuclide-derived denudation rates fall into latitudinal belts with (1) low rates of denudation in areas with high temperatures and high precipitation where rock fragments do not persist at the soil surface, (2) high rates of denudation at mid-latitudes where rock fragments exist and are carried efficiently by the river flow, and (3) low rates of denudation at high latitudes where large grains at the surface inhibit channelized

  14. Structure of the Asteroid Belt from the Gas Giants' Growth and Chaotic Dynamics (United States)

    Izidoro, André; Raymond, Sean N.; Pierens, Arnaud; Morbidelli, Alessandro; Winter, Othon; Nesvorny, David


    The structure of the asteroid belt holds a record of the Solar System's dynamical history. The current belt only contains 10-3 Earth masses yet the asteroids' orbits are dynamically excited, with a large spread in eccentricity and inclination. The belt is also chemically segregated: the inner belt is dominated by dry S-types and the outer belt by hydrated C-types. Here we propose a new model in which the asteroid belt was always low-mass and was partially populated and sculpted by the giant planets on chaotic, resonant orbits. We first show that the compositional dichotomy of the asteroid belt is a simple consequence of Jupiter's growth in the gaseous protoplanetary disk. As Jupiter's core rapidly grew by accreting gas, orbits of nearby planetesimals were perturbed onto Jupiter-crossing trajectories. A significant fraction (~10%) of objects in the neighborhood exterior of Jupiter's orbit were implanted by gas drag into the outer parts of the asteroid belt as C-types. While the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, we show that small perturbations may have driven them into a chaotic but stable state. After the dissipation of the gaseous disk, stochastic variations in the gas giants orbits caused resonances to chaotically jump across the main belt and excite the asteroids' orbits. Our results suggest that the early Solar System was chaotic and introduce a simple framework to understand the origins of the asteroid belt.

  15. The constraints of strain partitioning and geochronology in Luonan-Luanchuan tectonic belts on Qinling orogenic belt

    Institute of Scientific and Technical Information of China (English)


    The Luonan-Luanchuan tectonic belt lies between the North China Block and Qinling Mountains, in- cluding the Luonan-Luanchuan fault zone and the strong deformation zone to the north of the fault. The ductile shear zone, imbricate brittle fault and duplex structure in the fault zone now are the expression of the same tectonic event in different depth. Such lineation structure exists in the tectonic belts as mineral lineation, elongation lineation, crenulation lineation, sheath folds and so on, indicating NE-directed plate motion. Fold axes and thrusts in the strong deformation zone are inclined to the Luonan-Luanchuan fault zone at small angles. The structures with different natures show a regular pattern, produced during oblique convergence of plates. The convergence factors are as follows:The direction of plate convergence is 22°, 31° and the angle between the plate convergence direction and plate boundary is 73°, 82° respectively in the west and east segment. The Luonan-Luanchuan tectonic belt was deformed strongly in 372 Ma, resulted from Erlangping back-arc ocean basin subduction sin- istrally and obliquely to North China Block during the collision of North China Block and South China Block.


    International Nuclear Information System (INIS)

    Objects in the Edgeworth-Kuiper Belt and the main asteroid belt should emit microwaves that may give rise to extra anisotropy signals in the multipole of the cosmic microwave background (CMB) experiment. Constraints are derived from the absence of positive detection of such anisotropies for l ∼+. This limit is consistent with the mass extrapolated from the observable population with the size of a ∼> 15 km, assuming that the small-object population follows the power law in size dN/da ∼ a-q with the canonical index expected for collisional equilibrium, q ≅ 3.5, with which 23% of the mass is ascribed to objects smaller than are observationally accessible down to grains. A similar argument applied to the main asteroid belt indicates that the grain population should not increase more quickly than q ≅ 3.6 toward smaller radii, if the grain population follows the power law that continues to observed asteroids with larger radii. Both cases are at or only slightly above the limit that can be physically significant, implying the importance of further tightening the CMB anisotropy limit, which may be attained with observation at higher radio frequencies.

  17. Constraints on the gas content of the Fomalhaut debris belt; Can gas-dust interactions explain the belt's morphology?

    CERN Document Server

    Cataldi, G; Olofsson, G; Chen, C H; Dent, W R F; Kamp, I; Roberge, A; Vandenbussche, B


    Context: The 440 Myr old main-sequence A-star Fomalhaut is surrounded by an eccentric debris belt with sharp edges. Such a morphology is usually attributed to planetary perturbations, but the orbit of the only planetary candidate detected so far, Fomalhaut b, is too eccentric to efficiently shape the belt. Alternative models that could account for the morphology without invoking a planet are stellar encounters and gas-dust interactions. Aims: We aim to test the possibility of gas-dust interactions as the origin of the observed morphology by putting upper limits on the total gas content of the Fomalhaut belt. Methods: We derive upper limits on the CII 158 $\\mu$m and OI 63 $\\mu$m emission by using non-detections from the PACS instrument onboard the Herschel Space Observatory. Line fluxes are converted into total gas mass using the non-LTE code RADEX. We consider two different cases for the elemental abundances of the gas: solar abundances and abundances similar to those observed for the gas in the $\\beta$ Picto...

  18. Number of conveyor belts optimization regarding to its type and logistical parameters in mining industry

    International Nuclear Information System (INIS)

    Material transportation by belt conveyers is widely used in many industrial branches including mining plants. Belt conveying development during the last year was oriented mainly on construction of belts. The consequence of this is the improvement of its manufacture qualities bringing down the costs for their exchange and maintenance.Despite the fact that there are some theoretical calculations based on a standards it is common in the industry that the belt is not properly selected or it is over-designed or number of its types is too large what can lead to increased costs for its storage. The paper describes the optimization of number of belt types in mining company SIDERIT, s. r. o. Nizna Slana by the method of modernization and unification of belts under practical skills and projecting based on theoretical calculations. (authors)

  19. Timing belts - development milestones and innovations; Meilensteine und Innovationen der Zahnriemenentwicklung

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, H. [ContiTech Antriebssysteme GmbH, Hannover (Germany)


    Modern Timing Belts made of high temperature resistant elastomers for camshaft drives are designed for engine lifetime. Timing Belt drives gained in Europe 75% market share because of their advantages. The Belt drives generate up to 25% less friction than chain drives and create significantly lower noise levels. The new generation of Timing Belts are manufactured using: - special fibre glass types to transmit high forces with very high length stability - reinforced and Teflon treated fabrics to reduce friction and noise -high temperature resistant HNBR Elastomer to cover the temperature range (-40 C to +150 C) New belt drive developments are using Oval sprocket technology to eliminate unwanted vibrations and to reduce drive forces by 35%. Oil resistant Belts can substitute oil lubricated chains used for oil pump and camshaft drives to reduce the friction and noise level of the chain drives. (orig.)

  20. Experimental Study of Kinetic Properties of Pyrolysis for Conveyor Belt in Coal Mine

    Institute of Scientific and Technical Information of China (English)

    SONG Zheng-chang


    The combustion of conveyor belt is a leading factor of mine fire. In this paper, the pyrolysis properties of ordinary conveyor belt and fire-resistant belt were studied experimentally with thermo-gravimetric analysis and derivative thermo-gravimetric analysis, and the curves of pyrolysis properties were achieved. On this basis, the activation energy and reaction order of pyrolysis were obtained in combination with theoretical analysis, aiming to provide data for further numerical simulation and simulating experiment of mine fire.

  1. The "One Belt and One Road" is an Important Mutually Beneficial and Win-win Strategy

    Institute of Scientific and Technical Information of China (English)

    Long; Kaifeng


    The"One Belt and One Road"strategic conception carries the dream of development and prosperity of countries concerned,and gives the ancient Silk Road a brand new content of the time.In September and October 2013,President Xi Jinping proposed building the"New Silk Road Economic Belt"(One Belt)and the"Twenty-first Century Maritime Silk Road"(One Road)strategic conception respectively,emphasizing a mutual-beneficial and win-win

  2. Data From HANE-Generated Radiation Belts and the Origin of Diffusion Theory

    Energy Technology Data Exchange (ETDEWEB)

    Winske, Dan [Los Alamos National Laboratory


    In this presentation we briefly review some of the published data regarding the artificial radiation belts produced by the Starfish and R2 high altitude nuclear explosions in 1962. The data showed slow temporal variations of the belts in altitude (L) and pitch angle ({alpha}) that could be modeled as a diffusion process. That early work formed the basis for more complex radiation belt diffusion models that are in use at present.

  3. Progress in porphyry copper exploration from the Gangdise belt, Tibet, China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Youye; DUO Ji; CHENG Shunbo; GAO Shunbao; DAI Fanghua


    Recent mineral exploration in the Gangdise porphyry copper deposit belt, an important component of the Himalaya-Tethyan metallogenic belt, has led to the discovery of a number of deposits, as exemplified by the world-class Miocene Qulong porphyry Cu deposit. This paper reviews major advances in the studies of ore genesis and metallogenic regularity and progresses in mineral exploration of porphyry Cu deposits in the belt. Existing problems and suggestion for future exploration also are given.

  4. Saturn's radiation belts in the view of Cassini's MIMI/LEMMS observations (United States)

    Roussos, Elias; Krupp, Norbert; Kollmann, Peter; Paranicas, Chris; Armstrong, Tom P.; Mitchell, Donald G.; Krimigis, Stamatios M.; Kotova, Anna


    Energetic charged particle measurements by Cassini's MIMI/LEMMS detector between 2004 and 2013 have revealed that the processes which form and sustain Saturn's radiation belts differ significantly for their electron and ion components. The permanent MeV ion belts are relatively stable in intensity over both short and long time scales, they have a outer boundary that continuously coincides with the L-shell of Saturn's moon Tethys (L=4.89) and comprise different sectors, each separated from the other by an ion depleted region that is centered on an L-shell of one of the planet's inner icy moons. Fluxes within these belts are dominated by secondaries that result from nuclear collisions between Galactic Cosmic Rays and the planet's main rings and atmosphere. Extensions of the ion belts beyond the orbit of Tethys, that may last several months, may occur after the interaction of Saturn's magnetosphere with a Solar Proton Event. Still, these transient extensions have no impact on the structure of the inner belts, making these inner belts ideal for detailed and a precise studies of nuclear source processes, such as CRAND. Contrary to the ion belts, the electron radiation belt is a continuous structure that extends between the outer edge of the main rings and has its outer boundary at an average distance of about 8 Saturn radii from the planet. The latter distance scatters considerably from orbit to orbit, while flux levels within the belt may vary by several orders of magnitude. MIMI/LEMMS observations show a series of interesting features, such as recurrent sudden belt expansions with periods in the order of one to several weeks and considerably variable responses following periods of ICME interactions with Saturn's magnetosphere. As the elecron belts extend until the very dynamic middle magnetosphere and the dominant electron source and loss processes change as a function of L-shell, energy and pitch angle, modelling of these belts is very challenging.

  5. Geochemistry and U-Pb zircon ages of plutonic rocks from the Algodões granite-greenstone terrane, Troia Massif, northern Borborema Province, Brazil: Implications for Paleoproterozoic subduction-accretion processes (United States)

    Costa, Felipe Grandjean da; Palheta, Edney Smith de Moraes; Rodrigues, Joseneusa Brilhante; Gomes, Iaponira Paiva; Vasconcelos, Antonio Maurilio


    The Algodões metavolcano-sedimentary sequence is located at the northern margin of the Archean/Paleoproterozoic Troia Massif, northern Borborema Province (NE Brazil). It represents a well-preserved Paleoproterozoic greenstone-like sequence affected by two major plutonic events. The early plutonism, represented by the Cipó orthogneisses, mainly comprises biotite-bearing metatonalites, which share similar geochemical signatures with Archean tonalite-trondjhemite-granodiorite (TTG). For these rocks, we report U-Pb (LA-ICPMS) zircon ages of 2189 ± 14 Ma and 2180 ± 15 Ma. A subsequent plutonic magmatism occurred at ˜2150-2130 Ma and is mainly represented by hornblende-bearing dioritic to tonalitic orthogneisses of the Madalena Suite and São José da Macaoca Complex. Geochemical data indicate that these dioritic/tonalitic orthogneisses have adakitic characteristics and strongly suggest mantle-related magmas. A (sensu stricto) granite plutonism (Serra da Palha orthogneisses) also intruded the Algodões sequence and yielded U-Pb (LA-ICPMS) zircon age of 2150 ± 16 Ma. These granitic orthogneisses show high-K content, A-type characteristics and probably derived from partial melting of a crustal (tonalitic) source. We suggest that the early ˜2190-2160 Ma TTG plutons probably developed in intra-oceanic arc setting, whereas the following ˜2150-2130 Ma adakitic plutons and A-type granitic magmatism developed in response to arc-continent collision.

  6. The Migration Characteristics of Strong Earthquakes on the North-South Seismic Belt and Its Relation with the South Asia Seismic Belt

    Institute of Scientific and Technical Information of China (English)

    Wang Yipeng; Ma Jin; Li Chuanyou


    Migration of strong earthquakes (M≥7.0) along the North-South Seismic Belt of China since 1500 AD shows three patterns: Approximately equal time and distance interval migration from N to S, varied patterns of migration from S to N and grouped strong earthquake activity in a certain period over the entire seismic belt. Analysis of strong earthquakes in the past hundred years shows that the seismicity on the North-South Seismic Belt is also associated with strong earthquake activities on the South Asia Seismic Belt which extends from Myanmar to Sumatra, Indonesia. Strong earthquakes on the former belt often lag several months or years behind the quakes occurring on the later belt. So, after the occurrence of the December 26, 2004 M8.7 great earthquake off the western coast of Sumatra, Indonesia, the possibility of occurrence of strong earthquakes on the North-South Seismic Belt of China cannot be ignored. The above-mentioned migration characteristics of strong earthquakes are related to the northeastward collision and subduction of the India Plate as well as the interaction between the Qinghai-Xizang (Tibet) Plateau and the stable and hard Ordos and Alashan Massifs at its northeastern margin.

  7. Geological characteristics and metallogenic prognosis of main gold deposit in Altai gold ore belt, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    SHEN Yuan-chao; SHEN Ping; ZHENG Qing-dong; LIU Tie-bing; LI Guang-ming


    Altai polymetallic mineralization belt is famous copper-polymetallic mineralization belt in the world. There are a lot of gold deposits in the Altai ore belt in Xinjiang, China. These gold deposits belong to two genetic types: volcanogene late-stage hydrothermal type and fractured altered rock type. The authors discuss mainly the geological and mineralized features of fractured altered rock type of gold deposits in Altai gold ore belt. Base on this study, the metallogenic law is summarized and the deep metallogenic prognosis has been done in Duolanasayi and Tuokuzibayi gold deposits, and some mineralized anomalys have been discovered.

  8. Trace element mapping of pyrite from Archean gold deposits – A comparison between PIXE and EPMA

    Energy Technology Data Exchange (ETDEWEB)

    Agangi, A., E-mail: [University of Johannesburg, Department of Geology, Auckland Park 2006 (South Africa); Przybyłowicz, W., E-mail: [Materials Research Department, iThemba LABS, National Research Foundation, Somerset West 7129 (South Africa); AGH University of Science and Technology, Faculty of Physics & Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland); Hofmann, A., E-mail: [University of Johannesburg, Department of Geology, Auckland Park 2006 (South Africa)


    Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P–T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits.

  9. Trace element mapping of pyrite from Archean gold deposits - A comparison between PIXE and EPMA (United States)

    Agangi, A.; Przybyłowicz, W.; Hofmann, A.


    Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P-T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits.

  10. Sulfate in the Palaeoarchean Ocean: Localized Enrichment or Variable Preservation? (United States)

    Mason, P. R. D.; Roerdink, D. L.; Galic, A.; Martin, W.


    The Archean oceans are thought to have been depleted in sulfate, reflecting widespread anoxic conditions and limited input of oxidized sulfur species from atmospheric photolysis. This is supported by the paucity of sulfate-bearing minerals and the relatively limited mass-dependent sulfur isotope fractionation in the majority of the Archean geological record. An exception to this is the occurrence of barite deposits in the Palaeoarchean (3.5-3.2 Ga) which indicate spatial or temporal increases in sulfate concentration. The origin and extent of these enrichments remains controversial and has been difficult to assess due to limited and highly variable data. Here we compile an extensive new database of SIMS multiple sulfur isotope data for pyrite and barite from across the Barberton Greenstone Belt in South Africa in order to further investigate the extent and origin of any sulfate enrichment. Individual pyrites were measured with good stratigraphic and petrographic control. Pyrite δ56Fe was used to further delineate pyrite populations and pathways of pyrite formation. Our new sulfur isotope data support conventional models where a positive Δ33S was derived from heterogeneous photolytic elemental S, with negative Δ33S capturing a homogenized marine sulfate reservoir. Pyrite multiple S isotope data closely track the abundance of barite, suggesting that marine sulfate levels were generally low and that sulfate increases were sporadic and localized. We speculate that the subsequent Neoarchean scarcity was controlled by biological evolution.

  11. Trace element mapping of pyrite from Archean gold deposits – A comparison between PIXE and EPMA

    International Nuclear Information System (INIS)

    Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P–T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits

  12. Extensive Admixture and Selective Pressure Across the Sahel Belt. (United States)

    Triska, Petr; Soares, Pedro; Patin, Etienne; Fernandes, Veronica; Cerny, Viktor; Pereira, Luisa


    Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection). PMID:26614524

  13. On the oldest asteroid families in the main belt (United States)

    Carruba, V.; Nesvorný, D.; Aljbaae, S.; Domingos, R. C.; Huaman, M.


    Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects, such as diffusion in mean-motion resonances, Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the time-scales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the late heavy bombardment and that could provide clues on our understanding of the primitive Solar system? In this work, we investigate the dynamical stability of seven of the allegedly oldest families in the asteroid main belt. Our results show that none of the seven studied families has a nominally mean estimated age older than 2.7 Gyr, assuming standard values for the parameters describing the strength of the Yarkovsky force. Most `paleo-families' that formed between 2.7 and 3.8 Gyr would be characterized by a very shallow size-frequency distribution, and could be recognizable only if located in a dynamically less active region (such as that of the Koronis family). V-type asteroids in the central main belt could be compatible with a formation from a paleo-Eunomia family.

  14. DREAM3D simulations of inner-belt dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, Gregory Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    A 1973 paper by Lyons and Thorne explains the two-belt structure for electrons in the inner magnetosphere as a balance between inward radial diffusion and loss to the atmosphere, where the loss to the atmosphere is enabled by pitch-angle scattering from Coulomb and wave-particle interactions. In the 1973 paper, equilibrium solutions to a decoupled set of 1D radial diffusion equations, one for each value of the first invariant of motion, μ, were computed to produce the equilibrium two-belt structure. Each 1D radial diffusion equation incorporated an L-and μ-dependent `lifetime' due to the Coulomb and wave-particle interactions. This decoupling of the problem is appropriate under the assumption that radial diffusion is slow in comparison to pitch-angle scattering. However, for some values of μ and L the lifetime associated with pitch-angle scattering is comparable to the timescale associated with radial diffusion, suggesting that the true equilibrium solutions might reflect `coupled modes' involving pitch-angle scattering and radial diffusion and thus requiring a 3D diffusion model. In the work we show here, we have computed the equilibrium solutions using our 3D diffusion model, DREAM3D, that allows for such coupling. We find that the 3D equilibrium solutions are quite similar to the solutions shown in the 1973 paper when we use the same physical models for radial diffusion and pitch-angle scattering from hiss. However, we show that the equilibrium solutions are quite sensitive to various aspects of the physics model employed in the 1973 paper that can be improved, suggesting that additional work needs to be done to understand the two-belt structure.

  15. Colloidal Microworms Propelling via a Cooperative Hydrodynamic Conveyor Belt. (United States)

    Martinez-Pedrero, Fernando; Ortiz-Ambriz, Antonio; Pagonabarraga, Ignacio; Tierno, Pietro


    We study propulsion arising from microscopic colloidal rotors dynamically assembled and driven in a viscous fluid upon application of an elliptically polarized rotating magnetic field. Close to a confining plate, the motion of this self-assembled microscopic worm results from the cooperative flow generated by the spinning particles which act as a hydrodynamic "conveyor belt." Chains of rotors propel faster than individual ones, until reaching a saturation speed at distances where induced-flow additivity vanishes. By combining experiments and theoretical arguments, we elucidate the mechanism of motion and fully characterize the propulsion speed in terms of the field parameters. PMID:26451584

  16. Accuracy and performance analysis of a nuclear belt weigher

    International Nuclear Information System (INIS)

    Nuclear belt weighers have a broad range of applications in the solid particle industry. This work analyzes the accuracy and sensitivity of nuclear weighers for a wide range of operational conditions and design parameters. The problem of the effect of material profile and bulk density variations on the scale performance is quantitatively addressed. A new methodology is developed to calculate the minimum detectable load accounting for both accuracy and sensitivity. Accuracies of less than 1% can be achieved in some ideal situations by proper design of the source length and geometrical configuration. (orig.)

  17. Bio-assessment of water pollution in coal belt

    International Nuclear Information System (INIS)

    Water pollution in coal belt has attracted attention of scientists as well as general people. Implication of water pollution on bio-system is still a more important issue and a lot of information has been accumulated. Apart from conventional methods of pollution monitoring, bio-monitoring is comparatively a new approach and a proper methodology is still in pipeline. The present study reviews various methods of bio-monitoring and compare various methodologies suggested at population level with conventional methods. The results indicated that the bio-assessment methodology can be a tool and hence be developed. (author)

  18. Radial diffusion of radiation belt electrons in three dimensions (United States)

    Perry, Kara Lynn

    It is becoming increasingly important to understand the dynamics of radiation belt energetic particles given their potentially hazardous effects on satellites and our ever-increasing dependence on those satellites. There is a need to determine whether existing two-dimensional models are adequate in estimating the dynamics of the radiation belts or if a three-dimensional model is required. Discussion of general space physics and radiation belt topology is followed by an account of existing models and how these models can be improved by extending dynamic calculations from two dimensions to three. A model is then developed describing magnetic and electric fields associated with poloidal mode Pc5 ULF waves. The frequency and L dependence of the ULF wave power is included in this model by incorporating published ground-based magnetometer data. The influence of ultra low frequency (ULF) waves in the Pc5 frequency range on radiation belt electrons in a dipole magnetic field is examined. This is the first analysis in three dimensions utilizing model ULF wave electric and magnetic fields in the guiding center trajectories of relativistic electrons. It is demonstrated here that realistic spectral characteristics play a significant role in the rate of diffusion of relativistic electrons via drift resonance with poloidal mode ULF waves. Radial diffusion rates including bounce motion are calculated for alphaeq ≥ 50° (lambda ≤ 20°). Energy, L and pitch angle dependence of diffusion rates are calculated for L-independent, L-dependent, frequency independent and frequency dependent field power. During geomagnetic storms when ULF wave power is increased, ULF waves are a significant driver of increased fluxes of relativistic electrons inside geosynchronous orbit. Diffusion time scales obtained here, when frequency and L dependence compared to observations of ULF wave power is included, support this conclusion. A compression is then added to the dipole field model and diffusion

  19. WFIRST Ultra-Precise Astrometry I: Kuiper Belt Objects

    CERN Document Server

    Gould, Andrew


    I show that the WFIRST microlensing survey will enable detection and precision orbit determination of Kuiper Belt Objects (KBOs) down to H_vega=28.2 over an effective area of about 17 square deg. Typical fractional period errors will be ~1.5% X 10^{0.4(H-28.2)} with similar errors in other parameters for roughly 5000 KBOs. Binary companions to detected KBOs can be detected to even fainter limits, H_vega=29, corresponding to R~31 and effective diameters D~7.5 km. This will provide an unprecedented probe of orbital resonance and KBO mass measurements.

  20. Structure of the Irian Jaya Mobile BElt, Irian Jaya, Indonesia (United States)

    Nash, C. R.; Artmont, G.; Gillan, M. L.; Lennie, D.; O'Connor, G.; Parris, K. R.


    Image interpretation and field investigation over the Central Ranges of Irian Jaya has provided a structural overview of the inaccessible and largely unmapped Irian Jaya Mobile Belt (IJMB) in the region bounded by longitudes 136°30'E and 141°00'E. Throughout much of the southern (para-autochthonous) part of the belt, structural facing directions are visible on imagery through selective illumination of hogbacks and cuestas formed on thick-bedded Mesozoic siliciclastics and extensive Late Cretaceous-Neogene platform carbonate sequences. North of the regional Derewo Fault Zone, the Derewo Metamorphics are regarded in part as correlatives of the "metamorphosed Om Beds" in western Papua New Guinea and display a regional structural grain parallel to the orogen. The limited extent of spectrally anomalous features associated with ultramafic rocks indicate that ophiolites are confined to the southern part of the "Irian Jaya Ophiolite Belt", which may be largely composed of metamorphic rocks. Interpreted macroscopic and megascopic structures suggest the presence of seven discrete structural domains in the IJMB. From north to south these are (1) North Coast Basin region, consisting of Paleogene-Neogene volcanics and sediments overlain by a Pliocene-Pleistocene successor basin sequence; (2) an allochthonous terrane composed of ophiolites and high-grade metamorphic rocks; (3) the Derewo metamorphic assemblage, displaying polyphase deformation; (4) a complex marginal zone within Mesozoic-Paleogene miogeoclinal sediments which includes steep duplex structures and remnant klippen; (5) a 40 to 50-km-wide partly inverted synclinorium composed of miogeoclinal sediments; (6) a regional south vergent overturned anticlinorium formed by incompetent Paleozoic sediments; and (7) a foreland thrust domain involving both Mesozoic-Cenozoic miogeoclinal cover and a deformed Neogene foreland molasse basin sequence. The regional disposition of interpreted structures in the Irian Jaya Mobile

  1. Single beam optical conveyor belt for chiral particles

    CERN Document Server

    Fernandes, David E


    We propose a novel paradigm to selectively manipulate and transport small engineered chiral particles and discriminate different enantiomers using unstructured chiral light. It is theoretically shown that the response of a chiral metamaterial particle may be tailored to enable an optical conveyor belt operation with no optical traps, such that for a fixed incident light helicity and independent of the nanoparticle location, it is either steadily pushed towards the direction of the photon flow or steadily pulled against the photon flow. Our findings create new opportunities for unconventional optical manipulations of tailored nanoparticles and may have applications in sorting racemic mixtures of artificial chiral molecules and in particle delivery.

  2. Rapid energization of radiation belt electrons by nonlinear wave trapping

    Directory of Open Access Journals (Sweden)

    Y. Katoh


    Full Text Available We show that nonlinear wave trapping plays a significant role in both the generation of whistler-mode chorus emissions and the acceleration of radiation belt electrons to relativistic energies. We have performed particle simulations that successfully reproduce the generation of chorus emissions with rising tones. During this generation process we find that a fraction of resonant electrons are energized very efficiently by special forms of nonlinear wave trapping called relativistic turning acceleration (RTA and ultra-relativistic acceleration (URA. Particle energization by nonlinear wave trapping is a universal acceleration mechanism that can be effective in space and cosmic plasmas that contain a magnetic mirror geometry.

  3. Horizontal-belt filtration at Randfontein Estates Mine

    International Nuclear Information System (INIS)

    The paper describes tests on horizontal-belt filters for the filtration of gold and uranium. The promising results led to the installation of 17 such filters (ten of them 120 m2 in size) in the mine's metallurgical plants, and their operation is discussed. Although several problems were encountered both in operation and maintenance, it is concluded that, with correct operation and suitable filter cloths, exceptionally good metallurgical recoveries can be achieved at filtration rates twice to three times higher than those on rotary filters

  4. Ultra low frequency waves impact on radiation belt energetic particles

    Institute of Scientific and Technical Information of China (English)


    One of the most fundamental important issues in the space physics is to understand how solar wind energy transports into the inner magnetosphere.Ultra low frequency(ULF)wave in the magnetosphere and its impact on energetic particles,such as the wave-particle resonance,modulation,and particle acceleration,are extremely important topics in the Earth’s radiation belt dynamics and solar wind― magnetospheric coupling.In this review,we briefly introduce the recent advances on ULF waves study. Further,we will explore the density structures and ion compositions around the plasmaspheric boundary layer(PBL)and discuss its possible relation to the ULF waves.

  5. Architecture and Channel-Belt Clustering in the Fluvial lower Wasatch Formation, Uinta Basin, Utah (United States)

    Pisel, J. R.; Pyles, D. R.; Bracken, B.; Rosenbaum, C. D.


    The Eocene lower Wasatch Formation of the Uinta Basin contains exceptional outcrops of low net-sand content (27% sand) fluvial strata. This study quantitatively documents the stratigraphy of a 7 km wide by 300 meter thick strike-oriented outcrop in order to develop a quantitative data base that can be used to improve our knowledge of how some fluvial systems evolve over geologic time scales. Data used to document the outcrop are: (1) 550 meters of decimeter to half meter scale resolution stratigraphic columns that document grain size and physical sedimentary structures; (2) detailed photopanels used to document architectural style and lithofacies types in the outcrop; (3) thickness, width, and spatial position for all channel belts in the outcrop, and (4) directional measurements of paleocurrent indicators. Two channel-belt styles are recognized: lateral and downstream accreting channel belts; both of which occur as either single or multi-story. Floodplain strata are well exposed and consist of overbank fines and sand-rich crevasse splay deposits. Key upward and lateral characteristics of the outcrop documented herein are the following. First, the shapes of 243 channels are documented. The average width, thickness and aspect ratios of the channel belts are 110 m, 7 m, and 16:1, respectively. Importantly, the size and shape of channel belts does not change upward through the 300 meter transect. Second, channels are documented to spatially cluster. 9 clusters are documented using a spatial statistic. Key upward patterns in channel belt clustering are a marked change from non-amalgamated isolated channel-belt clusters to amalgamated channel-belt clusters. Critically, stratal surfaces can be correlated from mudstone units within the clusters to time-equivalent floodplain strata adjacent to the cluster demonstrating that clusters are not confined within fluvial valleys. Finally, proportions of floodplain and channel belt elements underlying clusters and channel belts

  6. Biomechanical considerations for assessing interactions of children and small occupants with inflatable seat belts. (United States)

    Rouhana, Stephen W; Sundararajan, Srinivasan; Board, Derek; Prasad, Priya; Rupp, Jonathan D; Miller, Carl S; Jeffreys, Thomas A; Schneider, Lawrence W


    NHTSA estimates that more than half of the lives saved (168,524) in car crashes between 1960 and 2002 were due to the use of seat belts. Nevertheless, while seat belts are vital to occupant crash protection, safety researchers continue efforts to further enhance the capability of seat belts in reducing injury and fatality risk in automotive crashes. Examples of seat belt design concepts that have been investigated by researchers include inflatable, 4-point, and reverse geometry seat belts. In 2011, Ford Motor Company introduced the first rear seat inflatable seat belts into production vehicles. A series of tests with child and small female-sized Anthropomorphic Test Devices (ATD) and small, elderly female Post Mortem Human Subjects (PMHS) was performed to evaluate interactions of prototype inflatable seat belts with the chest, upper torso, head and neck of children and small occupants, from infants to young adolescents. Tests simulating a 6-year-old child asleep in a booster seat, with its head lying directly on its shoulder on top of the inflatable seat belt, were considered by engineering judgment, to represent a worst case scenario for interaction of an inflating seat belt with the head and neck of a child and/or small occupant. All evaluations resulted in ATD responses below Injury Assessment Reference Values reported by Mertz et al. (2003). In addition, the tests of the PMHS subjects resulted in no injuries from interaction of the inflating seat belt with the heads, necks, and chests of the subjects. Given the results from the ATD and PMHS tests, it was concluded that the injury risk to children and small occupants from deployment of inflatable seat belt systems is low. PMID:24435728

  7. Main-Belt Comet P/2012 T1 (PANSTARRS)

    CERN Document Server

    Hsieh, Henry H; Novakovic, Bojan; Yang, Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Fitzsimmons, Alan; Jedicke, Robert; Kleyna, Jan; Veres, Peter; Wainscoat, Richard J; Ansdell, Megan; Elliott, Garrett T; Keane, Jacqueline V; Meech, Karen J; Moskovitz, Nicholas A; Riesen, Timm E; Sheppard, Scott S; Sonnett, Sarah; Tholen, David J; Urban, Laurie; Kaiser, Nick; Chambers, K C; Burgett, William S; Magnier, Eugene A; Morgan, Jeffrey S; Price, Paul A


    We present initial results from observations and numerical analyses aimed at characterizing main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between October 2012 and February 2013 using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research (SOAR) telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 microns that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of QCN100 Myr and is unlikely to be a rec...

  8. Future Rangeland Ecosystems in the Dryland Belt of Asia (United States)

    Qi, Jiaguo


    One of the greatest challenges humans are facing is sustainably managing water and land resources under changing global environment. This issue is especially pertinent in dryland belt in Asia where freshwater is scarce and shared among many nations. The region is heavily dependent on the diminishing Himalayan glaciers and limited and changing precipitation patterns. With increasing climate variability and a regional warming trend water security issues are acute and if not properly addressed could affect regional stability and lead to international conflicts. Solutions to these urgent regional issues are lacking and further research efforts are needed. Adaptive strategies addressing the complex and multifaceted water resource issues in the region will require a co-design and co-delivery of knowledge specific to the region and must consider exogenous factors such as policies of neighbouring countries and changing precipitation patterns due to climate change. There is a need to determine and fund scientific research priorities and practical approaches co-developed by local stakeholders and scientists to change the region's paradigm to "science for society". This presentation will summarize the collective outcome from a focused group discussion at the international workshop on "Future Earth and Science for Society" to be held from February 25-27, 2015 at Michigan State University, including knowledge gaps, research priorities, a general framework and international collaborations to move forward to addressing the future of the dyrland belt of Asia.

  9. Optimization of the dewatering performance of a steel belt filter

    Energy Technology Data Exchange (ETDEWEB)

    M.K. Mohanty; Z. Wang; Z. Huang; J. Hirschi [Southern Illinois University at Carbondale, Carbondale, IL (United States)


    The main goal of this study was to investigate the suitability of a newly developed fine particle dewatering technology, known as steel belt filter (SBF), for dewatering fine clean coal. The unique feature of this new technology is the combined use of both vacuum (suction force) and pressure (mechanical squeeze) for achieving the desired solid-liquid separation. A continuously operating SBF prototype unit having a belt width of 0.6 m was tested at the Illinois Coal Development Park. A factorial experimental design using the response surface methodology was conducted to optimize the dewatering performance of the SBF prototype unit. The clean coal slurry sample used as the dewatering feed was a combined spiral and flotation product with a mean particle size of 400 micron and an ash content of 19.2%. A solid recovery of greater than 99% was achieved by using a small dosage of an anionic flocculant. The minimum surface moisture content achieved by SBF dewatering was nearly 18.5%, whereas the mass product throughput capacity was 0.92 ton per hour (t/h) for a 0.6 wide SBF.

  10. Study of the NWC electrons belt observed on DEMETER Satellite

    CERN Document Server

    Li, Xinqiao; Wang, Ping; Wang, Huanyu; Lu, Hong; Zhang, Xuemin; Huang, Jianping; Shi, Feng; Yu, Xiaoxia; Xu, Yanbing; Meng, Xiangcheng; Wang, Hui; Zhao, Xiaoyun; Parrot, M


    We analyzed the data from 2007 to 2008, which is observed by IDP onboard DEMETER satellite, during ten months of NWC working and seven months of NWC shutdown. The characteristic of the space instantaneous electron belts, which come from the influence of the VLF transmitted by NWC, is studied comprehensively. The main distribution region of the NWC electron belts and the flux change are given. We also studied the distribution characteristic of the average energy spectrum in different magnetic shell at the height of DEMETER orbit and the difference of the average energy spectrum of the electrons in the drift loss-cone between day and night. As a result, the powerful power of NWC transmitter and the 19.8 kHz narrow bandwidth VLF emission not only created a momentary electrons enhancement region, which strides 180 degree in them longitude direction and from 1.6 to 1.9 in L value, with the rise of the electrons flux reaching to 3 orders of magnitude mostly, but also induced the enhancement or loss of electrons in ...

  11. Triggering Sublimation-Driven Activity of Main Belt Comets

    CERN Document Server

    Haghighipour, Nader; Schaefer, Christoph; Speith, Roland; Dvorak, Rudolf


    It has been suggested that the comet-like activity of Main Belt Comets are due to the sublimation of sub-surface water-ice that has been exposed as a result of their surfaces being impacted by m-sized bodies. We have examined the viability of this scenario by simulating impacts between m-sized and km-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle as well as different target material and water-mass fraction. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m suggesting that if the activation of MBCs is due to the sublimation of sub-surface water-ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice-exposure occurs in the bottom and on the interior surface of impact craters as well as the surface of the target where some of the ejected icy inclusions...

  12. Automation of belts; Automatizacion de Cintas de Interior

    Energy Technology Data Exchange (ETDEWEB)



    This document presents the most important aspects, and the results of the project DEVELOPMENT AND COMMISSIONING OF AN INTEGRATED HAULAGE AND VENTILATION CONTROL SYSTEM IN A MINE USING VERY LONG SUBLEVEL-CAVING WINNING METHOD. Project's targets were to develop, implement and commission a distributed control system for underground mining, which should allow the control and optimisation of the whole (continuous) haulage network. It should also integrate statutory safety features required for both winning and haulage. The system is capable of controlling the most common devices used in underground coal mining transport networks, like conveyor belts, armored conveyors, regulation silos, etc. from the winning faces to the surface, and also the interlocks between them. Moreover, the system implements statutory safety functions for conveyor belt operation, and for mining activities carried out in culls de sac. Specifically, for its relationship with the transport system, it should monitor secondary ventilation, fire damp and toxic gases concentration, and mains power presence in the culls de sac, which have already reached a length of 2000 m. The prototype was installed in the mine that Carbones de Pedraforca owns in Saldes, Barcelona. (Author)

  13. A reactor study on a belt-shaped screw pinch

    International Nuclear Information System (INIS)

    A previous study on a screw-pinch reactor with circular cross section (ECN-16 (1977) or Rijnhuizen report 77-101) has been extended to a belt configuration which allows to raise β to 0.5. The present study starts from the main assumptions and principal constraints of the previous work, but some technical aspects are treated more realistically. More attention has been paid to the modular construction, the non-uniform distribution of the wall loading, the thermo-hydraulics, the design of and the losses in the coil systems, and the energy storage and electric transmission systems. A potential use of the first wall of the blanket as part of the implosion coil system is suggested. Finally, a conceptual design of a reactor, with a cost estimate is given. Numerical results are given of parameter variations around the values for the reference reactor. The belt screw-pinch reactor with resistive coils turns out to be uneconomical because of its low net efficiency and its high capital costs. The application of superconducting coils to reduce the ohmic losses turns out to be a non-viable alternative. A more promising way to improve the energy balance seems to be the alternative scheme of fuel injection during the burn

  14. Finding the Faintest Exozodi and Asteroid Belt Analogs in WISE (United States)

    Patel, Rahul; Metchev, S.; Heinze, A.


    The presence of circumstellar dust in the terrestrial planet zone and asteroid belt regions of stars can be ascertained from the excess flux from main sequence stars in the near to mid-infrared wavelengths. Finding dust in these regions around stars is significant as it traces material related to terrestrial planet formation. In this study, we use the WISE All-Sky Survey data to detect circumstellar debris disks at the 12 and 22 μm bandpasses (W3 and W4, respectively). We present the detection of a sample of over 220 exozodi and asteroid belt analog candidates, 74% of which are brand new detections all at confidence levels >95%. This was done by cross-matching Hipparcos main-sequence stars with the WISE All-Sky Data Release for stars within 75 pc and outside the galactic plane (|b|>5°) and then seeking color excesses at W3 and W4. In addition to applying the standard WISE photometric flags and filters to remove contaminants from our sample, we also improved our selection techniques by correcting for previously unknown systematic behavior in the WISE photometry. Our debris disk candidates are reliable detections as well as unprecedentedly faint, due in large part to these improved selection techniques.

  15. Atmospheric scattering and decay of inner radiation belt electrons (United States)

    Selesnick, R. S.


    The dynamics of inner radiation belt electrons are governed by competing source, loss, and transport processes. However, during the recent extended solar minimum period the source was inactive and electron intensity was characterized by steady decay. This provided an opportunity to determine contributions to the decay rate of losses by precipitation into the atmosphere and of diffusive radial transport. To this end, a stochastic simulation of inner radiation belt electron transport is compared to data taken by the IDP instrument on the DEMETER satellite during 2009. For quasi-trapped, 200 keV electrons atL= 1.3, observed in the drift loss cone (DLC), results are consistent with electron precipitation losses by atmospheric scattering alone, provided account is taken of non-diffusive wide-angle scattering. Such scattering is included in the stochastic simulation using a Markov jump process. Diffusive small-angle atmospheric scattering, while causing most of the precipitation losses, is too slow relative to azimuthal drift to contribute significantly to DLC intensity. Similarly there is no contribution from scattering by VLF plasma waves. Energy loss, energy diffusion, and azimuthal drift are also included in the model. Even so, observed decay rates of stably-trapped electrons withL diffusion with coefficient DLL ˜ 3 × 10-10 s-1 to replenish electrons lost to the atmosphere at low L values.

  16. Northwest trending tectonic belt in the middle Yanshan Orogenic Belt of northeast Hebei Province, North China:Tectonic evolution and geochronology

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Changhou; WU; Ganguo; WANG; Genhou; ZHANG; Weijie


    The northwest trending tectonic belt in the middle part of the Mesozoic intraplate Yanshan Orogenic Belt, northeast Hebei Province, is composed of thrusts, extensional faults,strike-slip faults and syntectonic sedimentations as well. The northeastward basement-involved major thrusting deformation occurred between 174Ma and 168MaBP and was followed by an intrusion of the granitic plutonic rocks. As a part of the post-thrusting extensional deformations a northwest extending volcano-sedimentation system of Late Jurassic and Early Cretaceous formed in the southwest side of the belt. These volcano-sedimentary sequences are divided into Tuchengzi Formation, Zhangjiakou Formation, Yixian Formation and Jiufotang Formation respectively. They are characterized by southeastward migration as a result of the increasing down-dip slip displacement along the major extensional fault toward the southeast of the belt.The provenance area of the Jiufotang Formation north to it experienced southwestward thrusting during and after its later sedimentation. The thrusting in this stage resulted in the formation of an asymmetric footwall syncline with vergence to SW in the Jiufotang Formation in the NE side of the basin. Finally a dextral strike-slip deformation occurred along the NW tectonic belt. The striking tectono-geomorphological features and present seismic activities along this belt indicate that it has been being active since Cenozoic era and is still in the active state at present. This northwest extending tectonic belt was following the same direction and location as the existing fault systems within the basement as revealed by former geological and geophysical studies. So it is reasonable to infer the Mesozoic deformation along this belt to be a result of reactivation of the basement structures in a favorable tectonic stress field. The reactivation of basement structures might be taken as one of the mechanisms of intraplate deformation and orogeny.

  17. Green Belt - a case of ecological network in European cultural landscape

    Czech Academy of Sciences Publication Activity Database

    Bartoš, Michael; Kušová, Drahomíra; Zemek, František; Těšitel, Jan

    Brno : CZ-IALE Praha, 2007, s. 4-11. ISBN 978-80-86386-97-3 Grant ostatní: -(XE) Interreg IIIB CADSES Green Belt (5D107), PANET (5D194) Institutional research plan: CEZ:AV0Z60870520 Keywords : green belt * habitat system * nature protection * ecological network Subject RIV: EH - Ecology, Behaviour

  18. Algoma-type Neoproterozoic BIFs and related marbles in the Seridó Belt (NE Brazil)

    DEFF Research Database (Denmark)

    Sial, Alcides N.; Campos, Marcel S.; Gaucher, Claudio;


    The Jucurutu Formation in the Seridó Belt, northeastern Brazil, encompasses fine-to coarse-grained amphibolite-facies marbles, locally with cross-bedding and stromatolites. Banded iron formations (BIF) at three localities in this belt comprise itabirites (actinolite- or cummingtonite-itabirite and...

  19. 77 FR 30885 - Clarification of Prior Interpretations of the Seat Belt and Seating Requirements for General... (United States)


    ... Airplane Flight Manual (14 CFR 23.1581(j)). See 36 FR 12511; see also 14 CFR 23.562, 23.785; Legal... 121, part 91 did not require that each person have a separate seat and/or seat belt. See 36 FR 12511... Belt and Seating Requirements for General Aviation Flights AGENCY: Federal Aviation Administration...

  20. A mathematical analysis of a belt system with a low and time-varying velocity

    NARCIS (Netherlands)

    Suweken, Gede


    In this thesis a mathematical analysis has been given for model which describes the transversal vibrations of belt systems. The belt speed is assumed to be time-varying and to be small compared to the wave speed. Not only linear string-like or beam-like models but also nonlinear models have been stu

  1. Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt System

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.;


    We perform an analysis of the diffuse low-frequency Galactic components in the Southern part of the Gould Belt system (130^\\circ\\leq l\\leq 230^\\circ and -50^\\circ\\leq b\\leq -10^\\circ). Strong ultra-violet (UV) flux coming from the Gould Belt super-association is responsible for bright diffuse for...

  2. Thrust Belts and Foreland Basins——SGF/SGE Joint Earth Science Meeting

    Institute of Scientific and Technical Information of China (English)

    Olivier Lacombe; Jér(o)me Lavé; Fran(c)ois Roure


    @@ What is the important geologic information that thrust belts and foreland basins have recorded on the erogenic evolution of adjacent mountain belts? How can they reveal the coupled influence of deep (flexure, plate rheology and kinematics) and surficial (erosion, sedimentation) geological processes?

  3. A Parametric Energy Model for Energy Management of Long Belt Conveyors

    Directory of Open Access Journals (Sweden)

    Tebello Mathaba


    Full Text Available As electricity prices continue to rise, the increasing need for energy management requires better understanding of models for energy-consuming applications, such as conveyor belts. Conveyor belts are used in a wide range of industries, including power generation, mining and mineral processing. Conveyor technological advances are leading to increasingly long conveyor belts being commissioned. Thus, the energy consumption of each individual belt conveyor unit is becoming increasingly significant. This paper proposes a generic energy model for belt conveyors with long troughed belts. The model has a two-parameter power equation, and it uses a partial differential equation to capture the variable amount of material mass per unit length throughout the belt length. Verification results show that the power consumption calculations of the newly proposed simpler model are consistent with those of a known non-linear model with an error of less than 4%. The online parameter identification set-up of the model is proposed. Simulations indicate that the parameters can be identified successfully from data with up to 15% measurement noise. Results show that the proposed model gives better predictions of the power consumed and material delivered by a long conveyor belt than the steady-state models in the current literature.

  4. 14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses. (United States)


    ... shoulder harnesses. 23.785 Section 23.785 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... belts, and shoulder harnesses. There must be a seat or berth for each occupant that meets the following... and the attachment of— (1) Each seat to the structure; and (2) Each safety belt and shoulder...

  5. Injury pattern as an indication of seat belt failure in ejected vehicle occupants. (United States)

    Freeman, Michael D; Eriksson, Anders; Leith, Wendy


    Prior authors have suggested that when occupant ejection occurs in association with a seat belt failure, entanglement of the outboard upper extremity (OUE) with the retracting shoulder belt will invariably occur, leaving injury pattern evidence of belt use. In the present investigation, the authors assessed this theory using data accessed from the NASS-CDS for ejected front seat occupants of passenger vehicles. Logistic regression models were used to assess the associations between seat belt failure status and injuries. Injury types associated with seat belt failure were significant OUE and head injuries (OR = 3.87, [95% CI 1.2, 13.0] and 3.1, [95% CI 1.0, 9.7], respectively). The two injury types were found to be a predictor of seat belt use and subsequent failure only if combined with a high (≥0.8) precrash probability of belt use. The injury pattern associated with a seat belt failure-related ejection has limited use in the forensic investigation of crash-related ejections. PMID:24660766

  6. Spatially Resolved Images of Dust Belt(s) Around the Planet-hosting Subgiant Kappa CrB

    CERN Document Server

    Bonsor, Amy; Crepp, Justin R; Johnson, John A; Wyatt, Mark C; Sibthorpe, Bruce; Su, Kate Y L


    We present Herschel spatially resolved images of the debris disc orbiting the subgiant Kappa CrB. Not only are these the first resolved images of a debris disc orbiting a subgiant, but Kappa CrB is a rare example of an intermediate mass star where a detailed study of the structure of the planetary system can be made, including both planets and planetesimal belt(s). The only way to discover planets around such stars is to observe 'retired' A stars, which are cooler and slower rotators compared to their main-sequence counterparts. A planetary companion has already been detected orbiting the subgiant Kappa CrB, with revised parameters of m sin i = 2.1MJ and apl = 2.8AU (Johnson et al. 2008a). We present additional Keck I HIRES radial velocity measurements that provide evidence for a second planetary companion, alongside Keck II AO imaging that places an upper limit on the mass of this companion. Modelling of our Herschel images shows that the dust is broadly distributed, but cannot distinguish between a single w...

  7. Installation of a conveyor belt for hard coal shipments with optimized energy consumption in Kalimantan

    Energy Technology Data Exchange (ETDEWEB)

    Keller, M. [ContiTech Transportbandsysteme GmbH, Application Engineering Surface Mining, Northeim (Germany)


    In the late 1980s, a new coal deposit was opened up in Eastern Kalimantan, the Indonesian part of the island of Borneo. In the process of opening up the mine, PT Kaltim prima coal (KPC), the Indonesian mining company, installed an approximately 13 km long conveying system as the ''lifeline'' for shipping the processed coal to the loading place at the coast. After the first belt had reached the end of its lifecycle after 10 years of service, ContiTech Transportbandsysteme GmbH was commissioned in 2001 to equip the long-distance conveying system with a state-of-the-art belt. The guaranteed energy savings of 5% for the new belt resulted in savings of at least one third of the investment costs when setting off the energy savings against the new belt's expected service life as compared with the original belt. (orig.)

  8. How would increasing seat belt use affect the number of killed or seriously injured light vehicle occupants? (United States)

    Høye, Alena


    The expected effects of increasing seat belt use on the number of killed or seriously injured (KSI) light vehicle occupants have been estimated for three scenarios of increased seat belt use in Norway, taking into account current seat belt use, the effects of seat belts and differences in crash risk between belted and unbelted drivers. The effects of seat belts on fatality and injury risk were investigated in a meta-analysis that is based on 24 studies from 2000 or later. The results indicate that seat belts reduce both fatal and non-fatal injuries by 60% among front seat occupants and by 44% among rear seat occupants. Both results are statistically significant. Seat belt use among rear seat occupants was additionally found to about halve fatality risk among belted front seat occupants in a meta-analysis that is based on six studies. Based on an analysis of seat belt wearing rates among crash involved and non-crash involved drivers in Norway it is estimated that unbelted drivers have 8.3 times the fatal crash risk and 5.2 times the serious injury crash risk of belted drivers. The large differences in crash risk are likely to be due to other risk factors that are common among unbelted drivers such as drunk driving and speeding. Without taking into account differences in crash risk between belted and unbelted drivers, the estimated effects of increasing seat belt use are likely to be biased. When differences in crash risk are taken into account, it is estimated that the annual numbers of KSI front seat occupants in light vehicles in Norway could be reduced by 11.3% if all vehicles had seat belt reminders (assumed seat belt wearing rate 98.9%), by 17.5% if all light vehicles had seat belt interlocks (assumed seat belt wearing rate 99.7%) and by 19.9% if all front seat occupants of light vehicles were belted. Currently 96.6% of all (non-crash involved) front seat occupants are belted. The effect on KSI per percentage increase of seat belt use increases with increasing

  9. The Development of the “One Belt and One Road” and Its Impacts on China-U.S. Relations

    Institute of Scientific and Technical Information of China (English)

    Xia; Liping


    In 2013,Chinese President Xi Jinping has taken the initiatives of promoting the"One Belt and One Road".The"One Belt"refers to the Silk Road Economic Belt,and"One Road"to the 21st Century Maritime Silk Road.The"One Belt and One Road"has become one important part of China’s strategy of domestic economic and social development,as well as one important part of China’s foreign strategy.

  10. Periodic responses of a pulley-belt system with one-way clutch under inertia excitation (United States)

    Ding, Hu


    The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley-belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley-belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley-belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency-response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady

  11. Asteroid Belts in Debris Disk Twins: Vega and Fomalhaut (United States)

    Su, Kate Y. L.; Rieke, George H.; Malhortra, Renu; Stapelfeldt, Karl R.; Hughes, A. Meredith; Bonsor, Amy; Wilner, David J.; Balog, Zoltan; Watson, Dan M.; Werner, Michael W.; Misselt, Karl A.


    Vega and Fomalhaut are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred to as debris disk twins. We present Spitzer 10-35 micrometers spectroscopic data centered at both stars and identify warm, unresolved excess emission in the close vicinity of Vega for the first time. The properties of the warm excess in Vega are further characterized with ancillary photometry in the mid-infrared and resolved images in the far-infrared and submillimeter wavelengths. The Vega warm excess shares many similar properties with the one found around Fomalhaut. The emission shortward of approximately 30 micrometers from both warm components is well described as a blackbody emission of approximately 170 K. Interestingly, two other systems, Eri and HR 8799, also show such an unresolved warm dust using the same approach. These warm components may be analogous to the solar system s zodiacal dust cloud, but of far greater mass (fractional luminosity of approximately 10(exp-5) to 10(exp-6) compared to 10(exp-8) to 10(exp-7). The dust temperature and tentative detections in the submillimeter suggest that the warm excess arises from dust associated with a planetesimal ring located near the water-frost line and presumably created by processes occurring at similar locations in other debris systems as well. We also review the properties of the 2 micrometers hot excess around Vega and Fomalhaut, showing that the dust responsible for the hot excess is not spatially associated with the dust we detected in the warm belt.We suggest it may arise from hot nano grains trapped in the magnetic field of the star. Finally, the separation between the warm and cold belt is rather large with an orbital ratio greater than or approximately 10 in all four systems. In light of the current upper limits on the masses of planetary objects and the large gap, we discuss the possible implications for their underlying planetary architecture and suggest that multiple, low

  12. Exploring the Jupiter's and Saturn's radiation belts with LOFAR (United States)

    Girard, Julien N.; Zarka, Philippe; Pater Imke, de; Hess, Sebastien; Tasse, Cyril; Courtin, Regis; Hofstadter, Mark; Santos-Costa, Daniel; Nettelmann, Nadine; lorenzato, Lise


    Since its detection in the mid-fifties, the decimeter synchrotron radiation (DIM), originating from the radiation belts of Jupiter, has been extensively observed over a wide spectrum (from >300 MHz to 22 GHz) by various radio instruments (VLA, ATCA, WSRT, Cassini...). They provided accurate flux measurements as well as resolved maps of the emission that revealed spatial, temporal and spectral variabilities. The strong magnetic field (~4.2 G at the equator) is responsible for the radio emission generated by relativistic electrons. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility configuration (fast rotating 'dipole' magnetic field, beamed radio emission) and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) (e.g. de Pater & Klein, 1989; de Pater & Dunn, 2003; Bagenal (ed.) et al., 2004; Santos-Costa, 2009, 2011). A complete framework is necessary to fully understand the source, loss and transport processes of the electrons populating the inner magnetosphere over a wide frequency range. The low frequencies are associated with electron of lower energies situated in weaker magnetic field regions. LOFAR, the LOw Frequency ARray (LOFAR) (van Haarlem et al., 2012), the last generation of versatile and digital ground-based radio interferometer operates in the [30-250] MHz bandwidth. It brings very high time (~μsec), frequency (~kHz) and angular (~asec) resolutions and huge sensitivities (~mJy). In November 2011, a single 10-hour track enabled to cover an entire planetary rotation and led to image, for the first time, the radiation belts between 127-172 MHz (Girard et al. 2012, 2013). In Feb 2013, an 11-hour joint LOFAR/WSRT observing campaign seized the dyname state of the radiation belts from 45 MHz up to 5 GHz. We will present the current study of the radiation belts

  13. Petrology of plagiogranite from Sjenica, Dinaridic Ophiolite Belt (southwestern Serbia) (United States)

    Milovanović, Dragan; Srećković-Batoćanin, Danica; Savić, Marija; Popovic, Dana


    The Sjenica plagiogranite occurs in the southern part of the Dinaridic Ophiolite Belt, 5 km northwest of Sjenica. The main minerals are albite with strongly altered biotite (replaced with chlorite), with occasional amphibole (magnesio hornblende to tschermakite) and quartz. An enclave of fine-grained granitic rocks with garnet grains was noted too. Secondary minerals are calcite and chlorite (daphnite). Major, trace and REE geochemistry coupled with field observations support a model by which the Sjenica plagiogranite could be formed by fractional crystallization of mantle origin mafic magma in a supra-subduction zone setting. Occurrences of calcite and chlorite nests in the Sjenica plagiogranites revealed that these rocks underwent hydrothermal alteration due to intensive sea water circulation in a sub-sea-floor environment.

  14. Why style matters - uncertainty and structural interpretation in thrust belts. (United States)

    Butler, Rob; Bond, Clare; Watkins, Hannah


    Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

  15. Discussion on regional geo tectonic setting of Ganhang tectonic belt

    International Nuclear Information System (INIS)

    The knowledge of Precambrian structural framework in southern China has been progressed during a long period of study. Based on the comprehensive analysis on Precambrian formations and tectonic evolution the following conclusions are made: (1) The Cathaysia is a desintegrated Early Precambrian old land; (2) Zhexi-Gandongbei region was an active continental margin; (3) The Wuling orogeny is the most important one in the evolution of southern China during which a collision between the Cathaysia and Yangzi blocks occurred forming the united South China Old-land; (4) The Late Proterozoic tectonic evolution in various areas showed obvious difference because of the difference in regional geology. In a word, the Ganhang fault belt was an 'A' subduction zone in the early stage of Late Proterozoic

  16. Wave Energy Budget in the Earth Radiation Belts (United States)

    Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Mozer, Forest


    Whistlers are important electromagnetic waves pervasive in Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and ionization or chemical composition in the upper-atmosphere. Here, we report an analysis of ten-year Cluster data, evaluating for the first time the wave energy budget in Earth's magnetosphere and revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with ten times smaller magnetic power than parallel waves, typically have similar total energy. Very oblique waves may turn out to be a crucial agent of energy redistribution in Earth's radiation belts, controlled by solar activity.

  17. Using Kuiper Belt Binaries to Constrain Neptune's Migration History

    CERN Document Server

    Murray-Clay, Ruth A


    Approximately 10-20% of all Kuiper belt objects (KBOs) occupy mean-motion resonances with Neptune. This dynamical configuration likely resulted from resonance capture as Neptune migrated outward during the late stages of planet formation. The details of Neptune's planetesimal-driven migration, including its radial extent and the concurrent eccentricity evolution of the planet, are the subject of considerable debate. Two qualitatively different proposals for resonance capture have been proposed--migration-induced capture driven by smooth outward evolution of Neptune's orbit and chaotic capture driven by damping of the planet's eccentricity near its current semi-major axis. We demonstrate that the distribution of comparable-mass, wide-separation binaries occupying resonant orbits can differentiate between these two scenarios. If migration-induced capture occurred, this fraction records information about the formation locations of different populations of KBOs. Chaotic capture, in contrast, randomizes the orbits...

  18. On the oldest asteroid families in the main belt

    CERN Document Server

    Carruba, V; Aljbaae, S; Domingos, R C; Huaman, M


    Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects,such as diffusion in mean-motion resonances, Yarkovsky and YORP effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the timescales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the Late Heavy Bombardment and that could provide clues on our understanding of the primitive Solar System? In this work, we investigate the dynamical stability of seven of the allegedly oldest familie...

  19. Nonstorm loss of relativistic electrons in the outer radiation belt (United States)

    Katsavrias, Ch.; Daglis, I. A.; Turner, D. L.; Sandberg, I.; Papadimitriou, C.; Georgiou, M.; Balasis, G.


    We report observations of electron Phase Space Density (PSD) dropout and evidence that supports the loss mechanism of magnetopause shadowing and outward radial diffusion during a nonstorm period characterized by persistently positive values of the SYM->H index. On 14 April 2013 an electron PSD dropout of 2 orders of magnitude was observed at the nightside magnetosphere by the Van Allen Probes. The magnetopause shadowing was associated with a strong pulse attributed to the arrival of an interplanetary coronal mass ejection. It is shown, for the first time in detail, that significant losses to the magnetosheath may occur even in the absence of significant reconnection and magnetic storm activity. Signatures of substorm injections that penetrate the outer belt and enhance the low-energy electrons were also observed right after the interplanetary pressure pulse. Moreover, particle measurements from THEMIS constellation also show a PSD depletion in the dayside magnetosphere.

  20. Cosmic Roulette: Comets In The Main Belt Asteroid Region (United States)

    Beech, Martin; Gauer, Kai


    We have produced top ten ranked lists of impact velocity, mainbelt asteroid region dwell times and impact probabilities for a selection of short period comets. The comet with the combined highest ranking with respect to impact probability and impact velocity is Comet C/1766 G1 Helfenzrieder. Since it is not clear that this comet still exists, the highest ranked, presently active, comet with respect to the likelihood of suffering impacts from meter-sized objects while in the main belt asteroid region is Comet 28P/Neujmin 1. We find no evidence to support the existence of a distinctive sub-set of the short period comets liable to show repeated outburst or splitting behavioursdue to small body, meter-sized, asteroid impacts.

  1. Inward diffusion and loss of radiation belt protons (United States)

    Selesnick, R. S.; Baker, D. N.; Jaynes, A. N.; Li, X.; Kanekal, S. G.; Hudson, M. K.; Kress, B. T.


    Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (˜103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor ˜2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime ˜120 years.

  2. Qinling Orogenic Belt: Its Palaeozoic- Mesozoic Evolution and Metallogenesis

    Institute of Scientific and Technical Information of China (English)


    The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean- Palaeoproterozoic (3.0- 1.6 Ga), (2) plate evolution (0.8- 0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic. The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to extensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic were the main periods of enrichment of large amounts of metals. In the Devonian, many sedex-type massive Pb-Zn- (Cu)-Ag deposits were formed in the hydrothermal basins. In the Triassic (Indosinian-Yanshanian movements), many sediment-hosted disseminated gold deposits and reworked sedimentary type Pb-Zn-Hg-Sb (Au) deposits were formed in the rift hydrothermal basins. Many ductile shear zone-related gold deposits were formed in the restricted ocean basins and residual ocean basins on the two sides of the Qinling micro-plate. The above-mentioned discussion indicates that metallogenesis is not only consistent with geological events, but also controlled by them.

  3. Metamorphism and plutonism in the Quetico Belt, Superior Province, N.W. Ontario (United States)

    Percival, J. A.


    The Quetico Belt lies between the metavolcanic Wawa-Shebandowan and Wabigoon Belts. It consists of marginal metasedimentary rocks and central pelitic, gneissic and plutonic rocks. Metamorphism is Barrovian, at depths less than 10 km, and grade increases from margins to core of the belt: the outermost pelites are at chlorite-muscovite grade; inward a garnet-andalusite zone formed throughout the inner margin; and the central zone ranges form garnet-andalusite in the west and garnet-sillimanite-muscovite to garnet-sillimanite-cordierite and rare kyanite 6 to 150 km to the east. This increase is correlated with granitic intrusives. Migmatites in the core have intrusive leucosomes in the west and locally derived ones in the east. Isograd surfaces are steep where the belt is narrow and dip gently where it is wide. The Quetico Park intrusive complex of the central region of the Quetico Belt shows a zonation across it 20 to 50 km width from older, medium grained biotite composition to younger, coarse to pegmatitic granitic composition. Sediment of the Quetico basin had its source in the bordering metavolcanic belts and was deposited ca. 2.75 to 2.70 Ga ago. Boundaries of the belt dip inward, so it essentially is a graben of inter-arc or back-arc type.

  4. Seat belt syndrome: Delayed or missed intestinal injuries, a case report and review of literature (United States)

    Al-Ozaibi, Labib; Adnan, Judy; Hassan, Batool; Al-Mazroui, Alya; Al-Badri, Faisal


    Introduction Seat belt injuries are not uncommon. The use of seat belts is associated with a unique injury profile collectively termed “the seat belt syndrome”. The aim is to aid in the early diagnosis of seat belt injuries. Case presentation Two different patients presented to the emergency after sustaining a motor vehicle accident. Both were the drivers, restrained and had a frontal impact. On presentation they were hemodynamically stable with mild tenderness on the abdomen and the abdominal computed tomography (CT) did not show any signs of bowel or mesenteric injuries. The signs of peritonitis became obvious after 24 h in one case and after 3 days in the other. Discussion Early diagnosis provides better outcomes for patients with seat belt injuries, but this remains a challenge to trauma surgeons. The typical findings of peritonitis might not be present initially. The presence of abdominal wall ecchymosis (seat belt sign) increases the chance of intraabdominal injuries by eight folds. Conclusion Clinical signs of intestinal injuries might not be obvious on presentation. In the presence of seat belt sign the possibility of bowl injury must be suspected. Admit the patient for observation even if no clinical or radiological findings are present at presentation. PMID:26826929

  5. First ultraviolet reflectance measurements of several Kuiper Belt objects, Kuiper Belt object satellites, and new ultraviolet measurements of A Centaur

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S. A.; Schindhelm, E. [Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302 (United States); Cunningham, N. J., E-mail: [Nebraska Wesleyan University, 5000 Saint Paul Avenue, Lincoln, NE 68504 (United States)


    We observed the 2600-3200 Å (hereafter, mid-UV) reflectance of two Kuiper Belt Objects (KBOs), two KBO satellites, and a Centaur, using the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). Other than measurements of the Pluto system, these constitute the first UV measurements obtained of KBOs, and KBO satellites, and new HST UV measurements of the Centaur 2060 Chiron. We find significant differences among these objects, constrain the sizes and densities of Haumea's satellites, and report the detection of a possible spectral absorption band in Haumea's spectrum near 3050 Å. Comparisons of these objects to previously published UV reflectance measurements of Pluto and Charon are also made here.

  6. Tertiary sequence of deformation in a thin-skinned/thick-skinned collision belt: The Zagros Folded Belt (Fars, Iran) (United States)

    Mouthereau, F.; Tensi, J.; Bellahsen, N.; Lacombe, O.; de Boisgrollier, T.; Kargar, S.


    We describe how thin-skinned/thick-skinned deformation in the Zagros Folded Belt interacted in time and space. Homogeneous fold wavelengths (15.8 ± 5.3 km), tectono-sedimentary evidence for simultaneous fold growth in the past 5.5 ± 2.5 Ma, drainage network organization, and homogeneous peak differential stresses (40 ± 15 MPa) together point to buckling as the dominant process responsible for cover folding. Basin analysis reveals that basement inversion occurred ˜20 Ma ago as the Arabia/Eurasian plate convergence reduced and accumulation of Neogene siliciclastics in foreland basin started. By 10 Ma, ongoing contraction occurred by underplating of Arabian crustal units beneath the Iranian plate. This process represents 75% of the total shortening. It is not before 5 Ma that the Zagros foreland was incorporated into the southward propagating basement thrust wedge. Folds rejuvenated by 3-2 Ma because of uplift driven by basement shortening and erosion. Since then, folds grew at 0.3—0.6 mm/yr and forced the rivers to flow axially. A total shortening of 65-78 km (16-19%) is estimated across the Zagros. This corresponds to shortening rates of 6.5-8 km/Ma consistent with current geodetic surveys. We point out that although thin-skinned deformation in the sedimentary cover may be important, basement-involved shortening should not be neglected as it requires far less shortening. Moreover, for such foreland folded belts involving basement shortening, underplating may be an efficient process accommodating a significant part of the plate convergence.

  7. A method for automated control of belt velocity changes with an instrumented treadmill. (United States)

    Hinkel-Lipsker, Jacob W; Hahn, Michael E


    Increased practice difficulty during asymmetrical split-belt treadmill rehabilitation has been shown to improve gait outcomes during retention and transfer tests. However, research in this area has been limited by manual treadmill operation. In the case of variable practice, which requires stride-by-stride changes to treadmill belt velocities, the treadmill control must be automated. This paper presents a method for automation of asymmetrical split-belt treadmill walking, and evaluates how well this method performs with regards to timing of gait events. One participant walked asymmetrically for 100 strides, where the non-dominant limb was driven at their self-selected walking speed, while the other limb was driven randomly on a stride-by-stride basis. In the control loop, the key factors to insure that the treadmill belt had accelerated to its new velocity safely during the swing phase were the sampling rate of the A/D converter, processing time within the controller software, and acceleration of the treadmill belt. The combination of these three factors resulted in a total control loop time during each swing phase that satisfied these requirements with a factor of safety that was greater than 4. Further, a polynomial fit indicated that belt acceleration was the largest contributor to changes in this total time. This approach appears to be safe and reliable for stride-by-stride adjustment of treadmill belt speed, making it suitable for future asymmetrical split-belt walking studies. Further, it can be incorporated into virtual reality rehabilitation paradigms that utilize split-belt treadmill walking. PMID:26654110

  8. Analysis on damage cause of belt eyes for bypass feedwater isolation valves of Daya Bay and Ling'ao NPPs

    International Nuclear Information System (INIS)

    When all of bypass feedwater isolation valves of Daya Bay and Ling'ao NPPs were inspected under disassembled condition, it was found that the belt eyes were damaged in various degrees. The analysis on macro appearance, chemical composition, metallographic, Scanning Electron Microscope and fluid mechanics simulation were carried out on the damaged belt eyes. The results show that the flow rate of belt eye is well above the manufacturer's recommendation so that flow accelerated corrosion and cavitation erosion occur on the belt eyes. According to the damage causes of the belt eyes, corresponding corrective actions are proposed. (authors)

  9. Exponential decay to equilibrium for a fibre lay-down process on a moving conveyor belt


    Bouin, Emeric; Hoffmann, Franca; Mouhot, Clément


    We show existence and uniqueness of a stationary state for a kinetic Fokker-Planck equation modeling the fibre lay-down process in the production of non-woven textiles. Following a micro-macro decomposition, we use hypocoercivity techniques to show exponential convergence to equilibrium with an explicit rate assuming the conveyor belt moves slow enough. This work is an extention of [2], where the authors consider the case of a stationary conveyor belt. Adding the movement of the belt, the glo...

  10. Age distribution of detrital zircons in the psammitic schist of the Sanbagawa Belt, southwest Japan

    International Nuclear Information System (INIS)

    We measured the 206Pb/238U age distribution of detrital zircons in five psammitic schist samples from the Sanbagawa Belt in east-central Shikoku and the western Kii Peninsula to constrain their depositional age. The age-distribution diagrams for the five psammitic schist samples all show that detrital zircons of 100 to 90 Ma are most abundant and the age of the youngest zircon in each sample is less than 80 Ma. Considering the age of the retrogressive metamorphism of these psammitic schists, ca. 80-60 Ma, the protoliths age of the psammitic schists is constrained to 75-70 Ma, correlative to the age of the sandstone of the Middle Shimanto Belt (Yanai, 1984). A similar age-distribution has already been reported for two psammitic schist samples from the Central Unit of the Sanbagawa Belt in the Kanto Mountains (Tsutsumi et al., 2009). Thus the Sanbagawa Belt is most widely occupied by metamorphic rocks originating from rocks of the Middle Shimanto Belt. We also measured the 206Pb/238U age distribution of detrital zircons in Turonian sandstone from the Northern Shimanto Belt in the central Kii Peninsula. The age-distribution diagram shows that detrital zircons of around 128 Ma are most abundant and the age of the youngest zircon in the sample is about 100 Ma. A similar age-distribution has already been reported from a psammitic schist sample from the Southern Unit of the Sanbagawa Belt in the Kanto Mountains, overlying the Central Unit (Tsutsumi et al., 2009). The protolith age is still younger than the metamorphic age of the eclogites in central Shikoku, ca. 120-110 Ma (Okamoto et al., 2004), which occupy the uppermost portion of the Sanbagawa Belt. Although some previous studies suggested that the Sanbagawa Belt consists of metamorphosed Late Jurassic to Early Cretaceous accretionary complex, the present study shows that the belt is largely occupied by metamorphosed Late Cretaceous rocks: the Shimanto Metamorphic Rocks of Aoki et al. (2007). As a result, the

  11. Assessment of a three-point restraint system with a pre-tensioned lap belt and an inflatable, force-limited shoulder belt. (United States)

    Kent, Richard; Lopez-Valdes, Francisco J; Dennis, Nate J; Lessley, David; Forman, Jason; Higuchi, Kazuo; Tanji, Hiromasa; Ato, Tadayuki; Kameyoshi, Hikaru; Arbogast, Kristy


    This study investigates the performance of a 3-point restraint system incorporating an inflatable shoulder belt with a nominal 2.5-kN load limiter and a non-inflatable lap belt with a pretensioner (the "Airbelt"). Frontal impacts with PMHS in a rear seat environment are presented and the Airbelt system is contrasted with an earlier 3-point system with inflatable lap and shoulder belts but no load-limiter or pretensioners, which was evaluated with human volunteers in the 1970s but not fully reported in the open literature (the "Inflataband"). Key differences between the systems include downward pelvic motion and torso recline with the Inflataband, while the pelvis moved almost horizontally and the torso pitched forward with the Airbelt. One result of these kinematic differences was an overall more biomechanically favorable restraint loading but greater maximum forward head excursion with the Airbelt. The Airbelt is shown to generate generally lower head, neck, and thoracic injury metrics and PMHS trauma than other, non-inflatable rear-seat restraint concepts (viz., a standard 3-point belt and a pre-tensioned shoulder belt with a progressive load limiter). Further study is needed to evaluate the Airbelt system for different size occupants (e.g., children), non-frontal impact vectors, and for out-of-position occupants and to allow the results with this particular system to be generalized to a broader range of Airbelt designs. PMID:22869308

  12. Three Alkali—Rich Intrusive Rock Belts Bewly Discovered in the Mt.Kunlkun—Mt.Altun Region,Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    朱笑青; 王元龙; 等


    The newly discovered three alkali-rich intrusive rock belts in the Mt.Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive fock belt, the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beeilisai-Abulash alkali-rich intrusive rock belt.The former two belts were formed during the Yanshanian period,and the third one was formed during the Himalayan period,which is the youngest alkali-rich intrusive rock belt in China.The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.

  13. Three Alkali-Rich Intrusive Rock Belts Newly Discovered in the Mt. Kunlun-Mt. Altun Region, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    朱笑青; 王元龙; 毕华; 王中刚


    The newly discovered three alkali-rich intrusive rock belts in the Mt. Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive rock belt,the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beilisai-Abulash alkali-rich intrusive rock belt. The former two belts were formed during the Yanshanian period, and the third one was formed during the Himalayan period, which is the youngest alkali-rich intrusive rock belt in China. The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.

  14. The development of energy-optimized conveyor belts. A joint project of the Conveyor Belt Group of ContiTech AG and RWE Power AG; Entwicklung energieoptimierter Foerdergurte. Ein Gemeinschaftsprojekt der Conveyor Belt Group der ContiTech AG und der RWE Power AG

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, M. [RWE Power AG, Frechen (Germany). Technikzentrum Tagebaue/Bandanlagen/Foerdergurte


    In future, it is planned to have an energy-optimized conveyor belt quality replace the quality standard of today in the Rhenish lignite mining area. The whole lifecycle of a product must be considered, i.e. apart from procurement costs, operating and maintenance costs of belts must be taken into account as well. Since energy-optimized conveyor belts need to fulfil the same requirements as conventional belts with respect to service life and repairability of the material, the energy requirements of conveyor belts will be one of the crucial factors in deciding who is awarded a contract in future tendering procedures. (orig.)

  15. New Horizons mission to Pluto and the Kuiper belt (United States)

    McKinnon, W.; Stern, S.; Weaver, H.; Young, L.; Olkin, C.; New Horizons Science Team


    NASA's New Horizons (NH) Pluto-Kuiper Belt (PKB) mission was selected for development in 2001 following a competitive selection process. New Horizons is the first mission to the Pluto system and the Kuiper belt, and will complete the reconnaissance of the classical planets. The mission was launched on 19 January 2006 on a Jupiter Gravity Assist (JGA) trajectory toward the Pluto system, for a 14 July 2015 closest approach to Pluto; Jupiter closest approach occurred on 28 February 2007. The ˜400 kg spacecraft carries seven scientific instruments, including panchromatic and color imagers, UV and IR mapping spectrometers, radio science/radiometry, a plasma and particles suite, and a dust counter built by university students. These instruments are: Alice, an extreme to far-ultraviolet (50--180 nm) imaging spectrometer; Ralph, a combination of a) three panchromatic and four color imagers inside MVIC (Multispectral Visible Imaging Camera) and b) a short-wavelength infrared (1.25--2.50 micron) composition mapping spectrometer, called LEISA (Linear Etalon Imaging Spectral Array); REX (Radio science EXperiment), in which signal- processing electronics are integrated into the telecommunications system; LORRI (LOng Range Reconnaissance Imager), a panchromatic long focal length imager; SWAP (Solar Wind at Pluto), which will make energy (up to 6.5 keV) measurements of both the solar wind interaction with Pluto's atmosphere and of low energy pickup ions from Pluto; PEPSSI (Pluto Energetic Particle Spectrometer Science Investigation), which will determine the density, composition and nature of energetic (up to 1 MeV) particles escaping from Pluto's atmosphere; and the Venetia Burney Student Dust Counter (SDC), which has been tracing the dust density distribution across the entire Solar System for particles with masses as small as 1 pg. New Horizons will study the Pluto system over a 12-month period beginning in early 2015. Following that, NH plans to go on to reconnoiter one or


    Directory of Open Access Journals (Sweden)

    M. M. Buslov


    Full Text Available The terrain analysis concept envisages primarily a possibility of approximation of fragments / terrains of various geodynamic settings which belong to different plates. The terrain analysis can supplement the theory of plate tectonics in solving problems of geodynamics and tectonics of regions of the crust with complex structures. The Central Asian belt is among such complicated regions. Terrain structures occurred as a result of combined movements in the system of 'frontal' and/or oblique subduction – collision. In studies of geological objects, it is required first of all to prove their (vertical and horizontal autochthony in relations to each other and then proceed to paleogeodynamic, paleotectonic and paleogeographic reconstructions. Obviously, such a complex approach needs data to be obtained by a variety of research methods, including those applied to study geologic structures, stratigraphy, paleontology, paleogeography, lithothlogy, geochemistry, geochronology, paleomagnetism etc. Only by correlating such data collected from inter-disciplinary studies of the regions, it is possible to establish reliable characteristics of the geological settings and avoid mistakes and misinterpretations that may be associated with the 'stratigraphic' approach to solutions of both regional and global problems of geodynamics and tectonics of folded areas. The terrain analysis of the Central Asian folded belt suggests that its tectonic structure combines marginal continental rock complexes that were formed by the evolution of two major oceanic plates. One of them is the plate of the Paleo-Asian Ocean. As the analogue of the current Indo-Atlantic segment of Earth, it is characterised by the presence of continental blocks in the composition of the oceanic crust and the formation of oceanic basins resulting from the breakup of Rodinia and Gondvana. In the course of its evolution, super-continents disintegrated, and the blocks were reunited into the Kazakhstan

  17. Structure and Evolution of Kuiper Belt Objects and Dwarf Planets (United States)

    McKinnon, W. B.; Prialnik, D.; Stern, S. A.; Coradini, A.

    Kuiper belt objects (KBOs) accreted from a mélange of volatile ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of heating due to radioactive decay, the most important potential source being 26Al, whereas long-term evolution of large bodies is controlled by the decay of U, Th, and 40K. Several studies are reviewed dealing with the evolution of KBO models, calculated by means of one-dimensional numerical codes that solve the heat and mass balance equations. It is shown that, depending on parameters (principally rock content and porous conductivity), KBO interiors may have reached relatively high temperatures. The models suggest that KBOs likely lost ices of very volatile species during early evolution, whereas ices of less-volatile species should be retained in cold, less-altered subsurface layers. Initially amorphous ice may have crystallized in KBO interiors, releasing volatiles trapped in the amorphous ice, and some objects may have lost part of these volatiles as well. Generally, the outer layers are far less affected by internal evolution than the inner part, which in the absence of other effects (such as collisions) predicts a stratified composition and altered porosity distribution. Kuiper belt objects are thus unlikely to be "the most pristine objects in the solar system," but they do contain key information as to how the early solar system accreted and dynamically evolved. For large (dwarf planet) KBOs, long-term radiogenic heating alone may lead to differentiated structures -- rock cores, ice mantles, volatile-ice-rich "crusts," and even oceans. Persistence of oceans and (potential) volcanism to the present day depends strongly on body size and

  18. Study provides new evidence of back belts' effectiveness. (United States)

    McIntyre, D R; Bolte, K M; Pope, M H


    A major new study conducted by the UCLA School of Public Health has bolstered the claim that back support devices reduce low-back injuries. The study involved nearly 36,000 employees at Home Depot stores in California who logged 101 million work hours from 1989 through 1994. The company implemented mandatory wearing of belts in early 1990, and the study's authors reported that the workers' rate of acute low back injuries fell from 30.6 per million hours before implementation to 20.2 per million hours. UCLA Professor of Epidemiology Jess F. Kraus, the study's lead author, told The Wall Street Journal. "The study found a pretty big effect with a simple countermeasure. It is pretty hard to argue that it is a chance phenomenon." Kraus, who is the director of UCLA's Southern California injury Prevention Research Center, began his research by visiting 30 Home Depot stores to see whether employees were wearing the belts consistently. Compliance with the mandatory policy was quite high overall-above 98 percent, as calculated during an unannounced walk-through of all 77 stores in late 1993 and early 1994, according to the study. Back support manufactures hailed the Home Depot study as the largest long-term epidemiological study yet undertaken of the supports. It is proof, they said, that back supports are effective personal protective equipment-a contention at odds with the position of NIOSH the National institute for Occupational Safety and Health. In 1994, NIOSH reviewed the scientific literature and concluded there was not enough evidence to recommend that the supports be worn by uninjured workers. Sales plunged after NIOSH released its findings, according to the manufactures. The UCLA researchers found that low-back injuries declined in workers of both sexes, in younger workers as well as those older than 55, and among those with low levels of lifting as well as those with higher levels. The researchers concluded that mandatory use of back supports significantly reduces

  19. The Main Asteroid Belt: The Crossroads of the Solar System (United States)

    Michel, Patrick


    Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to

  20. The absolute magnitude distribution of Kuiper Belt objects

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, Wesley C. [Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Brown, Michael E. [Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Morbidelli, Alessandro [Laboratoire Lagrange, UMR7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d' Azur, BP 4229, F-06304 Nice (France); Parker, Alex [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Batygin, Konstantin, E-mail: [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 51, Cambridge, MA 02138 (United States)


    Here we measure the absolute magnitude distributions (H-distribution) of the dynamically excited and quiescent (hot and cold) Kuiper Belt objects (KBOs), and test if they share the same H-distribution as the Jupiter Trojans. From a compilation of all useable ecliptic surveys, we find that the KBO H-distributions are well described by broken power laws. The cold population has a bright-end slope, α{sub 1}=1.5{sub −0.2}{sup +0.4}, and break magnitude, H{sub B}=6.9{sub −0.2}{sup +0.1} (r'-band). The hot population has a shallower bright-end slope of, α{sub 1}=0.87{sub −0.2}{sup +0.07}, and break magnitude H{sub B}=7.7{sub −0.5}{sup +1.0}. Both populations share similar faint-end slopes of α{sub 2} ∼ 0.2. We estimate the masses of the hot and cold populations are ∼0.01 and ∼3 × 10{sup –4} M {sub ⊕}. The broken power-law fit to the Trojan H-distribution has α{sub 1} = 1.0 ± 0.2, α{sub 2} = 0.36 ± 0.01, and H {sub B} = 8.3. The Kolmogorov-Smirnov test reveals that the probability that the Trojans and cold KBOs share the same parent H-distribution is less than 1 in 1000. When the bimodal albedo distribution of the hot objects is accounted for, there is no evidence that the H-distributions of the Trojans and hot KBOs differ. Our findings are in agreement with the predictions of the Nice model in terms of both mass and H-distribution of the hot and Trojan populations. Wide-field survey data suggest that the brightest few hot objects, with H{sub r{sup ′}}≲3, do not fall on the steep power-law slope of fainter hot objects. Under the standard hierarchical model of planetesimal formation, it is difficult to account for the similar break diameters of the hot and cold populations given the low mass of the cold belt.

  1. Nonlinear VLF Wave Physics in the Radiation Belts (United States)

    Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Mithaiwala, M.; Rudakov, L.; Hospodarsky, G. B.; Kletzing, C.


    Electromagnetic VLF waves, such as whistler mode waves, both control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering and are responsible for the energization of electrons during storms. Traditional approaches to understanding the influence of waves on trapped electrons have assumed that the wave characteristics (frequency spectrum, wave-normal angle distribution, etc.) were both stationary in time and amplitude independent from event to event. In situ data from modern satellite missions, such as the Van Allen probes, are showing that this assumption may not be justified. In addition, recent theoretical results [Crabtree et al. 2012] show that the threshold for nonlinear wave scattering can often be met by naturally occurring VLF waves in the magnetosphere, with wave magnetic fields of the order of 50-100 pT inside the plasmapause. Nonlinear wave scattering (Nonlinear Landau Damping) is an amplitude dependent mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation. Laboratory results have confirmed the dramatic change in propagation direction when the pump wave has sufficient amplitude to exceed the nonlinear threshold [Tejero et al. 2014]. Nonlinear scattering can alter the macroscopic dynamics of waves in the radiation belts leading to the formation of a long-lasting wave-cavity [Crabtree et al. 2012] and, when amplification is present, a multi-pass amplifier [Ganguli et al., 2012]. Such nonlinear wave effects can dramatically reduce electron lifetimes. Nonlinear wave dynamics such as these occur when there are more than one wave present, such a condition necessarily violates the assumption of traditional wave-normal analysis [Santolik et al., 2003] which rely on the plane wave assumption. To investigate nonlinear wave dynamics using modern in situ data we apply the maximum entropy method [Skilling and Bryan, 1984] to solve for the wave distribution function

  2. Castalia - A Mission to a Main Belt Comet (United States)

    Jones, G. H.; Snodgrass, C.


    Main Belt Comets (MBCs), or Active Asteroids, constitute a newly identified class of solar system objects. They have stable, asteroid-like orbits and some exhibit a recurrent comet-like appearance. It is believed that they survived the age of the solarsystem in a dormant state and that their current ice sublimation driven activity only began recently. Buried water ice is the only volatile expected to survive under an insulating surface. Excavation by an impact can expose the ice and trigger the start of MBC activity. We present the case for a mission to one of these objects. The specific science goals of the Castalia mission are: 1. Characterize a new Solar System family, the MBCs, by in-situ investigation 2. Understand the physics of activity on MBCs 3. Directly sample water in the asteroid belt and test if MBCs are a viable source for Earth's water 4. Use the observed structure of an MBC as a tracer of planetary system formation and evolution. These goals can be achieved by a spacecraft designed to rendezvous with and orbit an MBC for a time interval of some months, arriving before the active period for mapping and then sampling the gas and dust released during the active phase. Given the low level of activity of MBCs, and the expectation that their activity comes from only a localized patch on the surface, the orbiting spacecraft will have to be able to maintain a very close orbit over extended periods - the Castalia plan envisages an orbiter capable of 'hovering' autonomously at distances of only a few km from the surface of the MBC. The strawman payload comprises a Visible and near-infrared spectral imager, Thermal infrared imager, Radio science,Subsurface radar, Dust impact detector, Dust composition analyser, Neutral/ion mass spectrometer, Magnetometer, and Plasma package. In addition to this, a surface science package is being considered. At the moment, MBC 133P/Elst Pizarro is the bestknown target for such a mission. A design study for the Castalia mission

  3. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 4 - Atlanta (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  4. CRED REA Fish Team Belt Transect Survey at Wake, Pacific Remote Island Areas (PRIAs), 2005 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 14 sites at Wake in the Pacific...

  5. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 9 - San Francisco (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  6. CRED REA Fish Team Belt Transect Surveys at Maro Reef, 2002 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 5 sites at Maro Reef in October,...

  7. CRED REA Fish Team Belt Transect Surveys at Pearl and Hermes Reef, 2002 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 17 sites at Pearl Hermes Reef in...

  8. CRED REA Fish Team Belt Transect Surveys at Laysan Island, 2002 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Laysan Island in...

  9. CRED REA Fish Team Belt Transect Surveys at French frigate Shoals, 2002 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  10. CRED REA Fish Team Belt Transect Surveys at the Midway Atoll, 2002 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Midway Atoll in...

  11. Dynamics simulation of the belt conveyor possessing feedback loop during starting

    Institute of Scientific and Technical Information of China (English)

    XI Ping-yuan; ZHANG Hai-tao; LIU Jun


    Synthesizing the mechanical models of the belt, the driver and the take-up device, the dynamics model was established on the longitudinal vibration of the overall belt conveyor system with finite elemental method, and S-function simulation block of asynchronous motor owing feedback function was built in Matlab/Simulink software, the simulation block indicates that motor rotation speed and its output moment vary with load and time, and the motor is a dynamic feedback system in working process. The state space block was adopted to express model of the belt. Thus it created simulation model of established dynamic model of overall belt conveyor system with Matlab/Simulink software, and simulates the course of starting by properly setting simulation parameters, and processes data for visualization.

  12. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 1 - Boston (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  13. The Contraction/Expansion History of Charon with implication for its Planetary Scale Tectonic Belt

    CERN Document Server

    Malamud, Uri; Schubert, Gerald


    The New-Horizons mission to the Kuiper Belt has recently revealed intriguing features on the surface of Charon, including a network of chasmata, cutting across or around a series of high topography features, conjoining to form a belt. It is proposed that this tectonic belt is a consequence of contraction/expansion episodes in the moon's evolution associated particularly with compaction, differentiation and geophysical reactions of the interior. The proposed scenario involves no need for solidification of a vast subsurface ocean and/or a warm initial state. This scenario is based on a new, detailed thermo-physical evolution model of Charon that includes multiple processes. According to the model, Charon experiences two contraction/expansion episodes in its history that may provide the proper environment for the formation of the tectonic belt. This outcome remains qualitatively the same even if we assume a different initial composition and mass. Two alternative explanations for the precise localization and orie...

  14. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 6 - Dallas (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  15. The foreland thrust belt in northwestern margin of Yangtze platform and the coalfield structure feature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.; Jing, Y. [Guangdon Bureau of Coal Geology (China)


    The accumulation and occurrence of coal resources in Yangtze platform and its northwest margin are controlled by the formation and evolution of foreland thrust belt in its northwest margin. The foreland thrust belt can be divided into root zone, middle zone and front zone. There is no coal accumulation root zone, the industrial coal resources are occurred in middle zone, and the coal resources occurred in the front zone are buried deeply. The coalfield structure deformation which is characterized by the imbricate thrusts, duplex thrust, parallel fold, inclined fold, klippen, thrust sheets and fault block, is resulted from the compressive stress of foreland thrust belt. The formation of the thrust belt is the result of long-time evolution of Tethys domain, in which the plates had collided three times along three sutures. 2 refs., 5 figs.

  16. CRED REA Fish Team Belt Transect Survey at Anatahan Island, 2003 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Anatahan Island in the...

  17. CRED REA Fish Team Belt Transect Survey at Saipan Island, 2003 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 5 sites at Saipan in the...

  18. CRED REA Fish Team Belt Transect Survey at Alamagan Island, 2003 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Alamagan Island in the...

  19. CRED REA Fish Team Belt Transect Survey at Wake Island, 2007 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Wake Island in the...

  20. CRED REA Fish Team Belt Transect Survey at Midway, NW Hawaiian Islands, 2006 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Midway in the NW...

  1. CRED REA Fish Team Belt Transect Surveys at Hawaii Island, 2005 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 19 sites at Hawaii Island in...

  2. CRED REA Fish Team Belt Transect Survey at Rose, American Samoa, 2006 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Rose in the American...

  3. CRED REA Fish Team Belt Transect Survey at Rota Island, 2003 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 6 sites at Rota in the...

  4. 76 FR 53660 - Federal Motor Vehicle Safety Standards; Seat Belt Assemblies (United States)


    ..., child passenger safety is an area of great importance to the agency. Children restrained using seat... involved in a collision would experience an inadvertent buckle release upon loading of the belt, and...

  5. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 5 - Chicago (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  6. CRED REA Fish Team Belt Transect Surveys at Lisianski Island, 2004 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Lisianski in October,...

  7. CRED REA Fish Team Belt Transect Survey at Stingray Shoals, 2003 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Stingray Shoals in the...

  8. CRED REA Fish Team Belt Transect Survey at Ta'u, 2004 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Ta'u Islands in...

  9. The WISE Survey of the Albedo Distribution of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, J.; Mainzer, A.; Grav, T.; Delbó, M.; Mueller, M.; WISE Team, [No Value


    Using date from the Wide-field Infrared Survey Explorer (WISE) we investigate the albedo distribution across the main belt of asteroids. When complete WISE will measure albedos and diameters for ~100,000 asteroids.

  10. CRED REA Fish Team Belt Transect Surveys at Johnston Island, 2004 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Johnston Island in...

  11. CRED REA Fish Team Belt Transect Survey at Guguan, Marianas Archipelago, 2007 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Guguan in the Marianas...

  12. CRED REA Fish Team Belt Transect Survey at French Frigate Shoals, NW Hawaiian Islands, 2006 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 10 sites at French Frigate Shoals...

  13. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 8 - Denver (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  14. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 10 - Seattle (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  15. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 2 - New York (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  16. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, All States (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  17. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 3 - Philadelphia (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  18. Isotopic evidence for two neoproterozoic high-grade metamorphic events in the Brazilia belt

    International Nuclear Information System (INIS)

    The Brasilia Belt is part of a Brasiliano/Pan African orogen developed between the Amazon and Sao Francisco cratons. The stabilization of the belt occurred after the last metamorphic event at ca. 620 Ma. There has been increasing geochronological evidence, however, for an older Neoproterozoic metamorphic event at ca. 780 Ma, observed mainly in high grade rocks of three large mafic-ultramafic complexes in the northern part of the belt. In this study we present: (i) new U-Pb and Sm-Nd geochronological data, (ii) a review of the existing metamorphic ages in the Brasilia Belt, and (iii) a discussion on the tectonic model to explain the two Neoproterozoic metamorphic ages (au)



    Manoel Cléber de Sampaio Alves; Luiz Fernando Frezzatti Santiago; Marcos Tadeu Tiburcio Gonçalves; Ivaldo De Domênico Valarelli; Francisco Mateus Faria de Almeida Varasquim


    The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size) on the output parameters (temperature and surface roughness) for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD). The results were...

  20. Organochlorine and organophosphorus pesticide residues in fodder and milk samples along Musi river belt, India


    Korrapati Kotinagu; Nelapati Krishnaiah


    Aim: The present study was conducted to find the organochlorine pesticide (OCP) and organophosphorus pesticide (OPP) residues in fodder and milk samples along Musi river belt, India. Materials and Methods: Fodder and milk samples collected from the six zones of Musi river belt, Hyderabad India were analyzed by gas chromatography with electron capture detector for OCP residues and pulsated flame photometric detector for the presence of OPP residues. Results: The gas chromatographic analysis of...

  1. The New Horizons Pluto Kuiper belt Mission: An Overview with Historical Context


    Stern, S. Alan


    NASA's New Horizons (NH) Pluto-Kuiper belt (PKB) mission was launched on 19 January 2006 on a Jupiter Gravity Assist (JGA) trajectory toward the Pluto system for a 14 July 2015 closest approach; Jupiter closest approach occurred on 28 February 2007. It was competitively selected by NASA for development on 29 November 2001. New Horizons is the first mission to the Pluto system and the Kuiper belt; and will complete the reconnaissance of the classical planets. The ~400 kg spacecraft carries sev...

  2. On the age of granulites in the Western Belomorian Belt and of the thrust formation

    International Nuclear Information System (INIS)

    To solve the problems relating to genesis of the Western Belomorian Belt the U-Pb dating method was employed for determining the age of zircons sampled from the rocks making up the belt. Estimated age (2727±32 mln. years) of orthopyroxenic diorites and tonalites crystallization from magma and their subsequent transformations under simultaneously occurring metamorphism of granulite fraction was obtained. Metamorphism of amphibolic facies correlates with thrust formation, its age 2707±1 mln. years


    Directory of Open Access Journals (Sweden)

    U. Batygin


    Full Text Available The technique of numerical processing of measurement results of pulse currents by means of Rogovsky belt application is offered in the given work. It is shown that at measurement of signals by digital oscillographs and further numerical transformation of target signals, the possibilities of Rogovsky belt without the application of additional devices that in turn allows to define parameters of pulse currents with any peak-time characteristics essentially expand.

  4. Goulds Belt, Interstellar Clouds, and the Eocene-Oligocene Helium-3 Spike (United States)

    Rubincam, David Parry


    Drag from hydrogen in the interstellar cloud which formed Gould's Belt may have sent small meteoroids with embedded helium to the Earth, perhaps explaining part or all of the (sup 3) He spike seen in the sedimentary record at the Eocene-Oligocene transition. Assuming the Solar System passed through part of the cloud, meteoroids in the asteroid belt up to centimeter size may have been dragged to the resonances, where their orbital eccentricities were pumped up into Earth-crossing orbits.

  5. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction


    Rebecca Gyawu; Quansah, Joseph E.; Souleymane Fall; Gichuhi, Peter N; Bovell-Benjamin, Adelia C


    In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs) were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%), restaurants (19.7%), fast food restaurants (16.4%), small supermarkets (8.2%), and large supermarket and farmers' markets (3.3 %), respectively. Although there we...

  6. Aeromagnetic and aeromagnetic-based geologic maps of the Coastal Belt, Franciscan Complex, northern California (United States)

    Langenheim, V.E.; Jachens, R.C.; McLaughlin, R.J.


    The Coastal belt of the Franciscan Complex represents a Late Cretaceous to Miocene accretionary prism and overlying slope deposits. Its equivalents may extend from the offshore outer borderland of southern California to north of the Mendocino Triple Junction under the Eel River Basin and in the offshore of Cascadia. The Coastal belt is exposed on land in northern California, yet its structure and stratigraphy are incompletely known because of discontinuous exposure, structural disruption, and lithologically non-distinctive clastic rocks. The intent of this report is to make available, in map form, aeromagnetic data covering the Coastal belt that provide a new dataset to aid in mapping, understanding, and interpreting the incompletely understood geology and structure in northern California. The newly merged aeromagnetic data over the Coastal belt of the Franciscan Complex reveal long, linear anomalies that indicate remarkably coherent structure within a terrane where mapping at the surface indicates complex deformation and that has been described as "broken formation" and, even locally as "melange". The anomalies in the Coastal belt are primarily sourced by volcanic-rich graywackes and exotic blocks of basalt. Some anomalies along the contact of the Coastal belt with the Central belt are likely caused by local interleaving of components of the Coast Ranges ophiolite. These data can be used to map additional exotic blocks within the Coastal belt and to distinguish lithologically indistinct graywackes within the Coastal terrane. Using anomaly asymmetry allows projection of these "layers" into the subsurface. This analysis indicates predominant northeast dips consistent with tectonic interleaving of blocks within a subduction zone.

  7. Measurement and monitoring of electrocardiogram belt tension in premature infants for assessment of respiratory function

    Directory of Open Access Journals (Sweden)

    Hegyi Thomas


    Full Text Available Abstract Background Monitoring of the electrocardiogram (ECG in premature infants with conventional adhesive-backed electrodes can harm their sensitive skin. Use of an electrode belt prevents skin irritation, but the effect of belt pressure on respiratory function is unknown. A strain gauge sensor is described which measures applied belt tension. Method The device frame was comprised of an aluminum housing and slide to minimize the device weight. Velcro tabs connected housing and slide to opposite tabs located at the electrode belt ends. The slide was connected to a leaf spring, to which were bonded two piezoresistive transducers in a half-bridge circuit configuration. The device was tested for linearity and calibrated. The effect on infant respiratory function of constant belt tension in the normal range (30 g–90 g was determined. Results The mechanical response to a step input was second order (fn = 401 Hz, ζ = 0.08. The relationship between applied tension and output voltage was linear in the range 25–225 gm of applied tension (r2 = 0.99. Measured device sensitivity was 2.18 mV/gm tension using a 5 V bridge excitation voltage. When belt tension was increased in the normal range from 30 gm to 90 gm, there was no significant change in heart rate and most respiratory functions during monitoring. At an intermediate level of tension of 50 gm, pulmonary resistance and work of breathing significantly decreased. Conclusion The mechanical and electrical design of a device for monitoring electrocardiogram electrode belt tension is described. Within the typical range of application tension, cardiovascular and respiratory function are not substantially negatively affected by electrode belt force.

  8. The Physiologic Responses of Dutch Belted Rabbits Infected with Inhalational Anthrax


    Lawrence, William S.; Hardcastle, Jason M; Brining, Douglas L; Weaver, Lori E; Ponce, Cindy; Whorton, Elbert B.; Johnny W. Peterson


    Bacillus anthracis, the causative agent of anthrax, is a category A priority pathogen that causes extensive damage in humans. For this reason, B. anthracis has been the focus of numerous studies using various animal models. In this study, we explored physiologic parameters in Dutch belted rabbits with inhalation anthrax to characterize the disease progression in this model. To this end, we infected Dutch belted rabbits with 100 LD50 B. anthracis Ames spores by nasal instillation and continuou...

  9. Poleward expansion of the tropical belt derived from upper tropospheric water vapour


    You, Qinglong; Min, Jinzhong; Kang, Shichang; Pepin, Nick


    Based on intersatellite-calibrated high-resolution infrared radiation sounder (HIRS) upper tropospheric water vapour (UTWV) brightness temperatures, the width of the tropical belt is defined as the distance between the latitudes at which maximum HIRS UTWV brightness temperatures are recorded in both hemispheres. Poleward expansion of the tropical belt is evident during 1979–2013 on an annual basis, with an average global magnitude of 1.57° latitude per decade. Most rapid widening is evident i...

  10. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    CERN Document Server

    Girard, J N; Tasse, C; Hess, S; de Pater, I; Santos-Costa, D; Nenon, Q; Sicard, A; Bourdarie, S; Anderson, J; Asgekar, A; Bell, M E; van Bemmel, I; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Breton, R P; Broderick, J W; Brouw, W N; Brüggen, M; Ciardi, B; Corbel, S; Corstanje, A; de Gasperin, F; de Geus, E; Deller, A; Duscha, S; Eislöffel, J; Falcke, H; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Hessels, J W T; Hoeft, M; Hörandel, J; Iacobelli, M; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Loose, M; Maat, P; Mann, G; Markov, S; McFadden, R; McKay-Bukowski, D; Moldon, J; Munk, H; Nelles, A; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Rowlinson, A; Schwarz, D; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; van Weeren, R J; Wijers, R A M J; Wucknitz, O


    Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electrons magnetically trapped around the planet (because in-situ particle data are limited in the inner magnetosphere). Aims. We perform the first resolved and low-frequency imaging of the synchrotron emission with LOFAR at 127 MHz. The radiation comes from low energy electrons (~1-30 MeV) which map a broad region of Jupiter's inner magnetosphere. Methods (see article for complete abstract) Results. The first resolved images of Jupiter's radiation belts at 127-172 MHz are obtained along with total integrated flux densities. They are compared with previous observations at higher frequencies and show a larger extent of the synchrotron emission source (>=4 $R_J$). The asymmetry and the dynamic of east-west emission peaks are measured and the presence of a hot spot at lambda_III=230 {\\deg} $\\pm$ 25 {\\deg}. Spectral flux density measurements ar...

  11. Uraniferous mineralizations in the Kuusamo Schist Belt, northeastern Finland

    International Nuclear Information System (INIS)

    The Kouveraara Co-Cu-Au mineralization was found in 1982 with the aid of a geophysical ground survey. This survey was connected with research on the Kouvervaara uranium mineralization in the Early Proterozoic Kuusamo Schist Belt, located just south of the Arctic Circle. In further work, using the Kouvervaara sulphide mineralization as a reference, six Co and Au bearing sulphide mineralizations were discovered, with the help of low altitude aerial geophysical techniques. The Co-Au mineralizations, hosted by the Sericite Quartzite Formation, occur within the hydrothermally altered zones. These zones consist of chloritization, carbonatization, sulphidization, sericitization and albitization, the latter being the most extensive. Excluding the Juomasuo mineralization, uranium is only a trace element in these mineralizations. Other characteristic trace elements are molybdenum and tungsten. The Sivakkaharju and Konttiaho Co-Au-U-Mo mineralizations were found by radiometric ground surveys carried out in 1985 and 1986. These hydrothermal mineralizations occur within brecciated quartz-albite-carbonate rocks and are good manifestations of the positive correlation between uranium and gold in the Kuusamo area. Compared with the other sulphide mineralizations, the Au, U, and Mo contents are remarkably high. Genetically, the mineralizations in the Kuusamo area are associated with deep seated fracture and fault zones, controlled by ancient intracontinental hot spot activity and continental rifting. (author). 31 refs, 6 figs, 2 tabs

  12. Belted kingfishers as ecological monitors of contamination: A review

    Energy Technology Data Exchange (ETDEWEB)

    Landrum, C.L. [North Texas Univ., Denton, TX (United States). Dept. of Biology; Ashwood, T.L.; Cox, D.K. [Oak Ridge National Lab., TN (United States)


    Aquatic systems serve as transport pathways and reservoirs for most of the contaminants known to be present on the Oak Ridge Reservation (ORR). Organisms that live in aquatic systems accumulate some of these contaminants from their food and directly from the water or sediment. A wide array of terrestrial organisms feeds on aquatic organisms and may accumulate contaminants from aquatic prey. The belted kingfisher (Ceryle alcyon) is a piscivorous and territorial avian species that may be a suitable monitor of contaminant accumulation at specific sites on the ORR. A kingfisher collected on White Oak Lake in 1991 had a {sup 137}Cs concentration of 568 pCi/g in muscle tissue, which exceeds levels found in any other waterfowl collected from the lake. An investigation into the efficacy of using the kingfisher as an ecological indicator of aquatic contaminants on the ORR was initiated in late August 1992. The primary objective of this study was to acquire information concerning the ecology of the kingfisher to determine how the species could be used within the framework of the Biological Monitoring and Abatement Program at Oak Ridge National Laboratory (ORNL). A second important objective of the study was to examine the possible somatic and reproductive effects of polychlorinated biphenyls (PCBs), Hg, and various radioactive contaminants on piscivorous birds by reviewing pollution ecology studies conducted on those species.

  13. Volatile Loss and Classification of Kuiper Belt Objects

    CERN Document Server

    Johnson, R E; Young, L A; Volkov, A N; Schmidt, C


    Observations indicate that some of the largest Kuiper Belt Objects (KBOs) have retained volatiles in the gas phase, which implies the presence of an atmosphere that can affect their reflectance spectra and thermal balance. Volatile escape rates driven by solar heating of the surface were estimated by Schaller and Brown (2007) (SB) and Levi and Podolak (2009)(LP) using Jeans escape from the surface and a hydrodynamic model respectively. Based on recent molecular kinetic simulations these rates can be hugely in error (e.g., a factor of $\\sim 10^{16}$ for the SB estimate for Pluto). In this paper we estimate the loss of primordial N$_2$ for several large KBOs guided by recent molecular kinetic simulations of escape due to solar heating of the surface and due to UV/EUV heating of the upper atmosphere. For the latter we extrapolate simulations of escape from Pluto (Erwin et al. 2013) using the energy limited escape model recently validated for the KBOs of interest by molecular kinetic simulations (Johnson et al. 2...

  14. Polygenic formation model of the planet's bituminous belts (United States)

    Dmitrievsky, A. N.; Balanyuk, I. E.


    In recent years, much attention has been paid to nontraditional hydrocarbon sources. Today the portion of nontraditional gas in the world extraction is 15% or 450 billion cubic meters, which hat makes up the volume of total gas exports from Russia. As is known, the easy-prospecting oil has been already found. The innovative technologies in geophysics, drilling, and excavation and the increased extraction coefficient expect further development and industrial compliance with these requirements. Based on calculations, the world oil reserves are now one trillion of stock tank barrels and one trillion barrels have been already extracted. The evergrowing demand for energy gives rise to the necessity of searching for and extracting more oil resources, and both these aspects are unique problems. The search for profitable petroleum deposits has become more and more difficult even in the leading companies. The increment of the world resources is a key vital question; therefore, the elaboration of criteria for the discovery of nontraditional deposits take on special significance in the economic respect. The authors are working out a conception that will be a guideline for future finding of the richest oil deposits in active geodynamic zones. For the first time, we suggest the polygenic formation model of the planet's bituminous belts.

  15. Baseline air quality evaluation for the Venezuelan Orinoco Bitumen Belt

    International Nuclear Information System (INIS)

    To achieve a harmonic relationship between oil exploration and production activities and the environment, Petroleos de Venezuela and its affiliated companies conducted environmental evaluations of the physical and bionic media in the Orinoco Bitumen Belt. This region covers an area of approximately 42000 km2 with estimated bitumen reserves on the order of 3 x 1012 barrels, one of the largest bitumen reservoirs in the world. This paper presents the results of a study of baseline air quality conditions: an emissions inventory, surface and upper layer meteorological conditions and measurements of air quality parameters of interest (CO, HC, NOx, SO2, H2S and T.S.P.) taken by a network of automated air quality stations using standard international reference techniques. The temporal (hourly and daily basis) and spatial air quality variability and the variables/activities that might determine the observed trends are discussed. NO, NO2, SO2 and H2S concentrations were lower than the detection limits of the analytical methods, while O3 and CO 1-hour average levels ranged from 5-30 ppb and 0.5-1.8 ppm, respectively, and T.S.P. daily means varied from 10-50 μg/m3, all of which is close to natural background concentrations. Maximum hourly average reactive hydrocarbon concentrations of 0.37 ppm were found near a producing oil field

  16. Size Distribution of Main-Belt Asteroids with High Inclination

    CERN Document Server

    Terai, Tsuyoshi


    We investigated the size distribution of high-inclination main-belt asteroids (MBAs) to explore asteroid collisional evolution under hypervelocity collisions of around 10 km/s. We performed a wide-field survey for high-inclination sub-km MBAs using the 8.2-m Subaru Telescope with the Subaru Prime Focus Camera (Suprime-Cam). Suprime-Cam archival data were also used. A total of 616 MBA candidates were detected in an area of 9.0 deg^2 with a limiting magnitude of 24.0 mag in the SDSS r filter. Most of candidate diameters were estimated to be smaller than 1 km. We found a scarcity of sub-km MBAs with high inclination. Cumulative size distributions (CSDs) were constructed using Subaru data and published asteroid catalogs. The power-law indexes of the CSDs were 2.17 +/- 0.02 for low-inclination ( 15 deg) MBAs in the 0.7-50 km diameter range. The high-inclination MBAs had a shallower CSD. We also found that the CSD of S-like MBAs had a small slope with high inclination, whereas the slope did not vary with inclinatio...

  17. Earthquake source characteristics along the arcuate Himalayan belt: Geodynamic implications

    Indian Academy of Sciences (India)

    Prosanta Kumar Khan; Md Afroz Ansari; S Mohanty


    The occurrences of moderate to large magnitude earthquakes and associated subsurface geological processes were critically examined in the backdrop of Indian plate obliquity, stress obliquity, topography, and the late Tertiary regional tectonics for understanding the evolving dynamics and kinematics in the central part of the Himalayas. The higher topographic areas are likely associated with the zones of depressions, and the lower topographic areas are found around the ridges located in the frontal part of the orogen. A positive correlation between plate and stress obliquities is established for this diffuse plate boundary. We propose that the zone of sharp bending of the descending Indian lithosphere is the nodal area of major stress accumulation which is released occasionally in form of earthquakes. The lateral geometry of the Himalayas shows clusters of seismicity at an angle of ∼20° from the centre part of the arc. Such spatial distribution is interpreted in terms of compression across the arc and extension parallel to the arc. This biaxial deformation results in the development of dilational shear fractures, observed along the orogenic belt, at an angle of ∼20° from the principal compressive stress axis.

  18. The Gould Belt 'MISFITS' Survey: The Real Solar Neighborhood Protostars

    CERN Document Server

    Heiderman, Amanda


    We present an HCO$^{+}$ J=3-2 survey of Class 0+I and Flat SED young stellar objects (YSOs) found in the Gould Belt clouds by surveys with Spitzer. Our goal is to provide a uniform Stage 0+I source indicator for these embedded protostar candidates. We made single point HCO$^{+}$ J = 3-2 measurements toward the source positions at the CSO and APEX of 546 YSOs (89% of the Class 0+I + Flat SED sample). Using the criteria from van Kempen et al. (2009), we classify sources as Stage 0+I or bona fide protostars and find that 84% of detected sources meet the criteria. We recommend a timescale for the evolution of Stage 0+I (embedded protostars) of 0.54 Myr. We find significant correlations of HCO$^{+}$ integrated intensity with ${\\alpha}$ and $T_{bol}$ but not with $L_{bol}$. The detection fraction increases smoothly as a function of ${\\alpha}$ and $L_{bol}$, while decreasing smoothly with $T_{bol}$. Using the Stage 0+I sources tightens the relation between protostars and high extinction regions of the cloud; 89% of ...

  19. Initial highlights from the Herschel Gould Belt survey

    CERN Document Server

    André, Ph; Bontemps, S; Könyves, V; Motte, F; Schneider, N; Didelon, P; Minier, V; Saraceno, P; Ward-Thompson, D; Di Francesco, J; White, G; Molinari, S; Testi, L; Abergel, A; Griffin, M; Henning, Th; Royer, P; Merín, B; Vavrek, R; Attard, M; Arzoumanian, D; Wilson, C D; Ade, P; Aussel, H; Baluteau, J -P; Benedettini, M; Bernard, J -Ph; Blommaert, J A D L; Cambrésy, L; Cox, P; Di Giorgio, A; Hargrave, P; Hennemann, M; Huang, M; Kirk, J; Krause, O; Launhardt, R; Leeks, S; Pennec, J Le; Li, J Z; Martin, P; Maury, A; Olofsson, G; Omont, A; Peretto, N; Pezzuto, S; Prusti, T; Roussel, H; Russeil, D; Sauvage, M; Sibthorpe, B; Sicilia-Aguilar, A; Spinoglio, L; Waelkens, C; Woodcraft, A; Zavagno, A


    We summarize the first results from the Gould Belt survey, obtained toward the Aquila Rift and Polaris Flare regions during the 'science demonstration phase' of Herschel. Our 70-500 micron images taken in parallel mode with the SPIRE and PACS cameras reveal a wealth of filamentary structure, as well as numerous dense cores embedded in the filaments. Between ~ 350 and 500 prestellar cores and ~ 45-60 Class 0 protostars can be identified in the Aquila field, while ~ unbound starless cores and no protostars are observed in the Polaris field. The prestellar core mass function (CMF) derived for the Aquila region bears a strong resemblance to the stellar initial mass function (IMF), already confirming the close connection between the CMF and the IMF with much better statistics than earlier studies. Comparing and contrasting our Herschel results in Aquila and Polaris, we propose an observationally-driven scenario for core formation according to which complex networks of long, thin filaments form first within molecul...

  20. Interpreting the Densities of the Kuiper Belt's Dwarf Planets

    CERN Document Server

    Barr, Amy C


    Kuiper Belt objects with absolute magnitude less than 3 (radius $\\gtrsim$500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g/cm$^3$. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent ...

  1. Dynamical implantation of objects in the Kuiper Belt

    Energy Technology Data Exchange (ETDEWEB)

    Brasil, P. I. O. [Instituto Nacional de Pesquisas Espaciais (INPE), ETE/DMC, Av. dos Astronautas, 1758, São José dos Campos (Brazil); Nesvorný, D.; Gomes, R. S., E-mail:, E-mail:, E-mail: [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Boulder, CO (United States)


    Several models have been suggested in the past to describe the dynamical formation of hot Kuiper Belt objects (hereafter Hot Classicals or HCs for short). Here, we discuss a dynamical mechanism that allows orbits to evolve from the primordial planetesimal disk at ≲ 35 AU to reach the orbital region now occupied by HCs. We performed three different sets of numerical simulations to illustrate this mechanism. Two of these simulations were based on modern theories for the early evolution of the solar system (the Nice and jumping-Jupiter models). The third simulation was performed with the purpose of increasing the resolution at 41-46 AU. The common aspect of these simulations is that Neptune scatters planetesimals from ≲ 35 AU to >40 AU and then undergoes a long phase of slow residual migration. Our results show that to reach an HC orbit, a scattered planetesimal needs to be captured in a mean motion resonance (MMR) with Neptune where the perihelion distance rises due to the Kozai resonance (which occurs in MMRs even for moderate inclinations). Finally, while Neptune is still migrating, the planetesimal is released from the MMR on a stable HC orbit. We show that the orbital distribution of HCs expected from this process provides a reasonable match to observations. The capture efficiency and the mass deposited into the HC region appears to be sensitive to the maximum eccentricity reached by Neptune during the planetary instability phase. Additional work will be needed to resolve this dependency in detail.

  2. Storm/substorm signatures in the outer belt

    International Nuclear Information System (INIS)

    The response of the ring current region is compared for periods of storm and substorm activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and substorm (AE) activity and examine compositional changes. Substorm activity leads to the intensification of the ring current at higher L (L ∼ 6) and lower ring current energies compared to storms (L ∼ 4). The O+/H+ ratio during substorms remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated substorms with an AE ∼ 900 nT lead to a ΔDst of ∼ 30 nT, but do not contribute to Dst during storm main phase as substorm injections do not form a symmetric ring current during such disturbed times

  3. Proton flux under radiation belts: near-equatorial zone

    International Nuclear Information System (INIS)

    In this work the features of low-energy proton flux increases in near-equatorial region (McIlvein parameter Lth the proton flux (with energy from tens keV up to several MeV) increases are registering regularly. However modern proton flux models (for example AP8 model) works at L>1.15 only and does not take into account near-equatorial protons. These fluxes are not too big, but the investigation of this phenomenon is important in scope of atmosphere-ionosphere connections and mechanisms of particles transport in magnetosphere. In according to double charge-exchange model the proton flux in near-equatorial region does not depend on geomagnetic local time (MLT) and longitude. However the Azur satellite data and Kosmos-484, MIR station and Active satellite data revealed the proton flux dependence on longitude. The other feature of near-equatorial proton flux is the dependence on geomagnetic local time revealed in the Sampex satellite experiment and other experiments listed above. In this work the dependences on MLT and longitude are investigated using the Active satellite (30-500 keV) and Sampex satellite (>800 keV). This data confirms that main sources of near-equatorial protons are radiation belts and ring current. The other result is that near-equatorial protons are quasi-trapped. The empirical proton flux dependences on L, B at near-equatorial longitudes are presented. (author)

  4. Belted kingfishers as ecological monitors of contamination: A review

    International Nuclear Information System (INIS)

    Aquatic systems serve as transport pathways and reservoirs for most of the contaminants known to be present on the Oak Ridge Reservation (ORR). Organisms that live in aquatic systems accumulate some of these contaminants from their food and directly from the water or sediment. A wide array of terrestrial organisms feeds on aquatic organisms and may accumulate contaminants from aquatic prey. The belted kingfisher (Ceryle alcyon) is a piscivorous and territorial avian species that may be a suitable monitor of contaminant accumulation at specific sites on the ORR. A kingfisher collected on White Oak Lake in 1991 had a 137Cs concentration of 568 pCi/g in muscle tissue, which exceeds levels found in any other waterfowl collected from the lake. An investigation into the efficacy of using the kingfisher as an ecological indicator of aquatic contaminants on the ORR was initiated in late August 1992. The primary objective of this study was to acquire information concerning the ecology of the kingfisher to determine how the species could be used within the framework of the Biological Monitoring and Abatement Program at Oak Ridge National Laboratory (ORNL). A second important objective of the study was to examine the possible somatic and reproductive effects of polychlorinated biphenyls (PCBs), Hg, and various radioactive contaminants on piscivorous birds by reviewing pollution ecology studies conducted on those species

  5. Kuiper belt structure around nearby super-Earth host stars

    CERN Document Server

    Kennedy, Grant M; Marmier, Maxime; Greaves, Jane S; Wyatt, Mark C; Bryden, Geoffrey; Holland, Wayne; Lovis, Christophe; Matthews, Brenda C; Pepe, Francesco; Sibthorpe, Bruce; Udry, Stéphane


    We present new observations of the Kuiper belt analogues around HD 38858 and HD 20794, hosts of super-Earth mass planets within 1 au. As two of the four nearby G-type stars (with HD 69830 and 61 Vir) that form the basis of a possible correlation between low-mass planets and debris disc brightness, these systems are of particular interest. The disc around HD 38858 is well resolved with Herschel and we constrain the disc geometry and radial structure. We also present a probable JCMT sub-mm continuum detection of the disc and a CO J=2-1 upper limit. The disc around HD 20794 is much fainter and appears marginally resolved with Herschel, and is constrained to be less extended than the discs around 61 Vir and HD 38858. We also set limits on the radial location of hot dust recently detected around HD 20794 with near-IR interferometry. We present HARPS upper limits on unseen planets in these four systems, ruling out additional super-Earths within a few au, and Saturn-mass planets within 10 au. We consider the disc st...

  6. Optimal linear filters for radiometric transport belt balances

    International Nuclear Information System (INIS)

    Due to a very short measuring path, dynamic measurement can be performed with the radiometric transport band balance. The stochastic perturbations of the measured signal afford the use of adequate filter algorithms. In the case of highly dynamical measurements it may even become necessary to improve the dynamics of the drive system. With essential improvements, the loading measurements can be performed far in front of the belt discharge location. For this purpose a solution is developed on the basis of an optimal control loop synthesis. A simpler solution is based on the optimal choise of the measuring point in order to compensate partially for the inertance of the drive. In addition a linear filter is used to process the radiometric signals. For the optimal design of this filter a method is used, which allows to limit the pulse response to a final time interval. As a consequence, analytical equations can be deduced for the calculation and discussion of the expected filter characteristic. (orig./DG)

  7. Dynamical delivery of volatiles to the outer main belt (United States)

    Grazier, Kevin R.; Castillo-Rogez, Julie C.; Sharp, Philip W.


    We quantify the relative contribution of volatiles supplied from outer Solar System planetesimal reservoirs to large wet asteroids during the first few My after the beginning of the Solar System. To that end, we simulate the fate of planetesimals originating within different regions of the Solar System - and thus characterized by different chemical inventories - using a highly accurate integrator tuned to handle close planet/planetesimal encounters. The fraction of icy planetesimals crossing the Asteroid Belt was relatively significant, and our simulations show that planetesimals originating from the Jupiter/Saturn region were orders of magnitude more abundant than those stemming from the Uranus and Neptune regions when the planets were just embryos. As the planets reached their full masses the Jupiter/Saturn and Saturn/Uranus regions contributed similar fractions of planetesimals for any material remaining in these reservoirs late in the stage of planetary formation, This implies that large asteroids like Ceres accreted very little material enriched in low-eutectic volatiles (e.g., methanol, nitrogen and methane ices, etc.) and clathrate hydrates expected to condense at the very low temperatures predicted for beyond Saturn’s orbit in current early solar nebula models. Further, a large fraction of the content in organics of Ceres and neighboring ice-rich objects originates from the outer Solar System.

  8. The Roles of Transport and Wave-Particle Interactions on Radiation Belt Dynamics (United States)

    Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua


    Particle fluxes in the radiation belts can vary dramatically during geomagnetic active periods. Transport and wave-particle interactions are believed to be the two main types of mechanisms that control the radiation belt dynamics. Major transport processes include substorm dipolarization and injection, radial diffusion, convection, adiabatic acceleration and deceleration, and magnetopause shadowing. Energetic electrons and ions are also subjected to pitch-angle and energy diffusion when interact with plasma waves in the radiation belts. Important wave modes include whistler mode chorus waves, plasmaspheric hiss, electromagnetic ion cyclotron waves, and magnetosonic waves. We investigate the relative roles of transport and wave associated processes in radiation belt variations. Energetic electron fluxes during several storms are simulated using our Radiation Belt Environment (RBE) model. The model includes important transport and wave processes such as substorm dipolarization in global MHD fields, chorus waves, and plasmaspheric hiss. We discuss the effects of these competing processes at different phases of the storms and validate the results by comparison with satellite and ground-based observations. Keywords: Radiation Belts, Space Weather, Wave-Particle Interaction, Storm and Substorm

  9. Biomechanical caracterisation of lumbar belt by full-field techniques: Preliminary results

    CERN Document Server

    Bonnaire, Rebecca; Calmels, Paul; Convert, Reynald


    In France, 50% of the population per year is suffering from low back pain. Lumbar belt are frequently proposed as a part of the treatment of this pathology. However mechanical ways of working of this medical device is not clearly understood, but abdominal pressure is often related. So an optical method was developed in this study to measure strain in lumbar belt and trunk interface and to derive a pressure estimation. Optical method consisted of coupling fringe projection and digital image correlation (DIC). Measurement has been carried out on the right side of a manikin wearing a lumbar belt. Average strain is 0.2 and average pressure is 1 kPa. Continuation of this study will be comparison of strain and pressure in different areas of lumbar belt (left side, front and back) and comparison of different lumbar belts. Results will be used in a finite elements model to determine lumbar belt impact in intern body. In long term, this kind of study will be done on human.

  10. The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt

    CERN Document Server

    Hsieh, Henry H


    The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: (1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit, or (2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If (1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if (2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. I conducted just such a survey -- the Hawaii Trails Project -- of selected main-belt asteroids in a search for objec...

  11. Discussion about the relationship between seismic belt and seismic statistical zone

    Institute of Scientific and Technical Information of China (English)

    潘华; 金严; 胡聿贤


    This paper makes a summary of status of delimitation of seismic zones and belts of China firstly in aspects of studying history, purpose, usage, delimiting principles, various presenting forms and main specialties. Then the viewpoints are emphasized, making geographical divisions by seismicity is just the most important purpose of delimiting seismic belts and the concept of seismic belt is also quite different from that of seismic statistical zone used in CPSHA method. The concept of seismic statistical zone and its history of evolvement are introduced too. Large differences between these two concepts exist separately in their statistical property, actual meaning, gradation, required scale, and property of refusing to overlap each other, aim and usage of delimitation. But in current engineering practice, these two concepts are confused. On the one hand, it causes no fit theory for delimiting seismic statistical zone in PSHA to be set up; on the other hand, researches about delimitation of seismic belts with purposes of seismicity zoning and studying on structural environment, mechanism of earthquake generating also pause to go ahead. Major conclusions are given in the end of this paper, that seismic statistical zone bases on the result of seismic belt delimiting, it only arises in and can be used in the especial PSHA method of China with considering spatially and temporally inhomogeneous seismic activities, and its concept should be clearly differentiated from the concept of seismic belt.

  12. Global-scale coherence modulation of radiation-belt electron loss from plasmaspheric hiss (United States)

    Breneman, A. W.; Halford, A.; Millan, R.; McCarthy, M.; Fennell, J.; Sample, J.; Woodger, L.; Hospodarsky, G.; Wygant, J. R.; Cattell, C. A.; Goldstein, J.; Malaspina, D.; Kletzing, C. A.


    Over 40 years ago it was suggested that electron loss in the region of the radiation belts that overlaps with the region of high plasma density called the plasmasphere, within four to five Earth radii, arises largely from interaction with an electromagnetic plasma wave called plasmaspheric hiss. This interaction strongly influences the evolution of the radiation belts during a geomagnetic storm, and over the course of many hours to days helps to return the radiation-belt structure to its `quiet' pre-storm configuration. Observations have shown that the long-term electron-loss rate is consistent with this theory but the temporal and spatial dynamics of the loss process remain to be directly verified. Here we report simultaneous measurements of structured radiation-belt electron losses and the hiss phenomenon that causes the losses. Losses were observed in the form of bremsstrahlung X-rays generated by hiss-scattered electrons colliding with the Earth's atmosphere after removal from the radiation belts. Our results show that changes of up to an order of magnitude in the dynamics of electron loss arising from hiss occur on timescales as short as one to twenty minutes, in association with modulations in plasma density and magnetic field. Furthermore, these loss dynamics are coherent with hiss dynamics on spatial scales comparable to the size of the plasmasphere. This nearly global-scale coherence was not predicted and may affect the short-term evolution of the radiation belts during active times.

  13. Classification of the rift zones of venus: Rift valleys and graben belts (United States)

    Guseva, E. N.


    The spatial distribution of rift zones of Venus, their topographic configuration, morphometric parameters, and the type of volcanism associating with rifts were analyzed. This allowed the main characteristic features of rifts to be revealed and two different types of rift-forming structures, serving for classification of rift zones as rift valleys and graben belts, to be isolated. These structural types (facies) of rift zones are differently expressed in the relief: rift valleys are individual deep (several kilometers) W-shaped canyons, while graben belts are clusters of multiple V-shaped and rather shallow (hundreds of meters) depressions. Graben belts are longer and wider, as compared to rift valleys. Rift valleys are spatially associated with dome-shaped volcanic rises and large volcanos (concentrated volcanic sources), while graben belts do not exhibit such associations. Volcanic activity in the graben belts are presented by spacious lava fields with no apparent sources of volcanism. Graben belts and rift valleys were formed during the Atlian Period of geologic history of Venus, and they characterized the tectonic style of the planet at the late stages of its geologic evolution. Formation of this or that structural facies of the rift zones of Venus were probably governed by the thickness of the lithosphere, its rheological properties, and the development degree of the mantle diapirs associating with rift zones.


    International Nuclear Information System (INIS)

    The size distribution of the asteroid belt is examined with 16956 main belt asteroids detected in data taken from the Canada-France-Hawaii Telescope Legacy Survey in two filters (g' and r'). The cumulative H (absolute magnitude) distribution is examined in both filters, and both match well to simple power laws down to H = 17, with slopes in rough agreement with those reported the literature. This implies that disruptive collisions between asteroids are gravitationally dominated down to at least this size, and probably sub-kilometer scales. The slopes of these distributions appear shallower in the outer belt than the inner belt, and the g' distributions appear slightly steeper than the r'. The slope shallowing in the outer belt may reflect a real compositional difference: the inner asteroid belt has been suggested to consist mostly of stony and/or metallic S-type asteroids, whereas carbonaceous C-types are thought to be more prevalent further from the Sun. No waves are seen in the size distribution above H = 15. Since waves are expected to be produced at the transition from gravitationally-dominated to internal strength-dominated collisions, their absence here may imply that the transition occurs at sub-kilometer scales, much smaller than the H = 17 (diameter ∼ 1.6 km) cutoff of this study.

  15. Seismic tomography beneath the orogenic belts and adjacent basins of northwestern China

    Institute of Scientific and Technical Information of China (English)


    Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave recorded in seismic networks in Xinjiang, Qinghai, Gansu of China and Kyrgyzstan. The velocity images of upper crust demonstrate the tectonic framework on the ground surface. High velocities are observed beneath orogenic belts, and low velocities are observed in the basins and depressions that are obviously related to unconsolidated sediments. The velocity image in mid-crust maintains the above features, and in addition low velocities appear in some earthquake regions and a low velocity boundary separates the western Tianshan Mts. from eastern Tianshan Mts. The orogenic belts and the northern Tibetan plateau have a Moho depth over 50 km, whereas the depths of the Moho in basins and depressions are smaller than 50 km. The velocity images of upper mantle clearly reveal the colliding relationship and location of deep boundaries of the continental blocks in northwestern China, indicating a weakness of the upper mantle structure of orogenic belts. The top depth of upper mantle asthenosphere varies from place to place. It seems shallower under the northern Tibetan plateau, Altay and Qilian Mts., and deeper under the Tarim and Tianshan regions. Hot mantle probably rose to the bottom of some orogenic belts along tectonic boundaries when continental blocks collided to each other. Therefore their dynamic features are closely correlated to the formation and evolution of orogenic belts in northwestern China.

  16. Silicone foam molding method for sealing timing belt cover gasket; Timing belt gasket no happo silicone gomu tofu gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Kagosaki, T.; Omura, S.; Yamaguchi, H. [Toyota Motor Corp., Aichi (Japan)


    An automated assembly of a timing belt cover gasket succeeded by changing a gasket material from molding rubber to silicone foam rubber and making a coating application process with the change. Since a conventional molding rubber gasket was unstable to shape and difficult to integrate in the automation, a method was examined for applying a liquid silicone foam rubber, a building material. A silicone foam rubber as a building material had problems such that reaction was fast after two liquids were mixed, that hardening occurred in the mixed part, and that the viscosity was so low as to make a 3-dimensional application impossible. Consequently, a material was developed for a two-liquid heat setting type that commenced reaction by heating. An application process excellent in quality and yield was completed. In the system containing a device for mixing and discharging two liquids, by enlarging the bore diameter of a discharge nozzle, cutting liquid at the tip end of the nozzle, making a mixer with a small number of revolution and small capacity, using the material in which reaction starting temperature was raised to suppress the reaction inside the mixer, and so on. Thus, the automation was successfully carried out. 16 figs., 1 tab.

  17. Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada (United States)

    Savage, James C.; Simpson, Robert W.


    The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

  18. Interpreting the Densities of the Kuiper Belt's Dwarf Planets (United States)

    Barr, Amy C.; Schwamb, Megan E.


    Kuiper Belt objects with absolute magnitude less than 3 (radius ≳500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g/cm3. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent of the total colliding mass, is lost. The fragments would not remain in physical or dynamical proximity to the parent body. The ice loss process has not yet been demonstrated numerically, which could be due to the paucity of KBO origin simulations, or missing physical processes in the impact models. If our hypothesis is correct, we predict that large KBOs with small moons should be denser than the primordial material, and that the mean density of Orcus should be close to the primordial value.

  19. Magnetoacoustic heating and FCT-equilibria in the belt pinch

    International Nuclear Information System (INIS)

    In the HECTOR belt pinch of high β plasma is produced by magnetic compression in a Tokamak geometry. After compresseion the initial β value can be varied between 0.2 and 0.8. During 5 μs the plasma is further heated by a fast magnetoacoustic wave with a frequency near the first harmonic of the ion cyclotronfrequency. For the first time the β-value of a pinch plasma could be increased further from 0.34 after compression to 0.46 at the end of the rf-heating cycle. By proper selection of the final β-value the region for resonance absorption of the heating wave can be shifted. Strong heating (200 MW) has been observed in the cases, where the resonance region has been located in the center of the plasma. In deuterium discharges an increase in ion temperature is observed during the heating process, whereas the electrons are energetically decoupled, showing no temperature increase. Strong plasma losses are found in the 200 MW range after the rf-heating process. The dominant mechanisms are charge exchange collisions with neutral gas atoms. During rf-heating and the subsequent cooling phase the magnetic flux is frozen due to the high conductivity of the plasma. The observed equilibria could be identified as flux conserving Tokamak (FCT) equilibria. Based on a two-dimensional code the time-evolution of the equilibria has been calculated. The q-profiles are time-independent, with increasing β the magnetic axis of the plasma is shifted towards the outer boundary of the torus, and finally the linear relation between β and βsub(pol), which is characteristic for low-β-equilibria, is no longer valid. Thus for the first time the existence of FCT-equilibria at high β has been demonstrated experimentally together with a qualitative agreement with FCT-theory. (orig./AH)

  20. The New Horizons Mission to Pluto and the Kuiper Belt (United States)

    Weaver, H. A.; Stern, S. A.; New Horizons Science; Engineering Team

    New Horizons, which initiates the NASA New Frontiers program of mid-sized missions, will provide the first scientific reconnaissance of the Pluto-Charon system and is scheduled for launch in January 2006. An encounter with Jupiter at a flyby distance of ˜32-45 RJ about 13 months after launch provides a gravity boost for the spacecraft's journey to Pluto and practice for the Pluto encounter, in addition to providing an opportunity to perform a valuable set of scientific measurements within the jovian system. New Horizons carries a sophisticated suite of instruments to perform ultraviolet and infrared spectroscopy, panchromatic and color optical imaging, and charged particle and dust measurements, all within a spacecraft having a total mass of ˜465 kg and total power output of ˜210 W at the time of Pluto encounter in July 2015. The primary scientific objectives of the New Horizons are to characterize the global geology and morphology of Pluto and Charon, map the surface composition of Pluto and Charon, and characterize the neutral atmosphere and its escape rate, but many other important scientific objectives will be addressed as well. New Horizons has the capability to image Pluto with a resolution exceeding that provided by the Hubble Space Telescope for at least 90 days prior to closest approach at a distance of ˜10,000 km from the surface, at which time a resolution of ˜100 m will be achieved for selected regions near the terminator. After encounter, the spacecraft will pass through the shadows of both Pluto and Charon, which enables radio and ultraviolet occultation measurements of their atmospheres. If an extended mission phase is approved, the spacecraft will be re-targeted to encounter one or more Kuiper belt objects (KBOs), roughly 3 years after the Pluto encounter at a heliocentric distance of ˜42 AU. The scientific objectives for the KBO encounters are similar to those for the Pluto encounter.

  1. Aeromagnetic Study of Tke Huichapan Caldera; Central Volcanic Belt (United States)

    Gonzalez, T.; Martin, A.; Alfaro, G.; Oyarzabal, E.


    Analysis of the aeromagnetic anomalies over the central sector of the Mexican Volcanic Belt sheds new light on the structure of the Huichapan Caldera. This volcanic center located 100 Km to the north- northwest of Mexico City is approximately 10 km in diameter and related to an ignimbrite sequence. Milan et al, (1993) and. Aguirre-Diaz and Lopez-Martinez (2009) mapped Huichapan area and described the geology and petrology of the erupted products in the region. Aguirre-Diaz and Lopez-Martinez (2009) suggest the idea of two overlapping calderas related to an ignimbrite sequence. The analyzed region is a rectangular area, approximately from 20.25 N to 20.42 N and between 99.42 W and 99.6 W. The total field aeromagnetic data was obtained with a Geometrics G-803 proton magnetometer at a flight altitude of 300 m above ground level. For the analysis of the anomalies, the data was further smoothed to construct a 1 km regularly spaced grid. The anomaly map was compared with the surface geology and larger anomalies were correlated with major volcanic features. Since our main interest was in mapping the subsurface intrusive and volcanic bodies, the total field magnetic anomalies were reduced to the pole by using the double integral Fourier method. The reduced to the pole anomaly map results in a simplified pattern of isolated positive and negative anomalies, which show an improved correlation with all major volcanic structures. For the analysis and interpretation of the anomalies, the reduced to the pole anomalies were continued upward at various reference levels. These operations result in smoothing of the anomaly field by the filtering of high frequency anomalies that may be related to shallow sources. Two profiles were selected that cross the major anomalies on the Huichapan Caldera. The Talwani algorithm for 2-D polygonal bodies has been used for calculating the theoretical anomalies.

  2. Interpreting the densities of the Kuiper belt's dwarf planets (United States)

    Barr, Amy C.; Schwamb, Megan E.


    Kuiper belt objects (KBOs) with absolute magnitude less than 3 (radius ≳500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g cm-3. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent of the total colliding mass, is lost. The fragments would not remain in physical or dynamical proximity to the parent body. The ice loss process has not yet been demonstrated numerically, which could be due to the paucity of KBO origin simulations, or missing physical processes in the impact models. If our hypothesis is correct, we predict that large KBOs with small moons should be denser than the primordial material, and that the mean density of Orcus should be close to the primordial value.


    Energy Technology Data Exchange (ETDEWEB)

    Fang, Julia; Margot, Jean-Luc [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Rojo, Patricio [Departamento de Astronomia, Universidad de Chile, Santiago (Chile)


    Sylvia is a triple asteroid system located in the main belt. We report new adaptive optics observations of this system that extend the baseline of existing astrometric observations to a decade. We present the first fully dynamical three-body model for this system by fitting to all available astrometric measurements. This model simultaneously fits for individual masses, orbits, and primary oblateness. We find that Sylvia is composed of a dominant central mass surrounded by two satellites orbiting at 706.5 {+-} 2.5 km and 1357 {+-} 4.0 km, i.e., about 5 and nearly 10 primary radii. We derive individual masses of 1.484{sup +0.016}{sub -0.014} Multiplication-Sign 10{sup 19} kg for the primary (corresponding to a density of 1.29 {+-} 0.39 g cm{sup -3}), 7.33{sup +4.7}{sub -2.3} Multiplication-Sign 10{sup 14} kg for the inner satellite, and 9.32{sup +20.7}{sub -8.3} Multiplication-Sign 10{sup 14} kg for the outer satellite. The oblateness of the primary induces substantial precession and the J{sub 2} value can be constrained to the range of 0.0985-0.1. The orbits of the satellites are relatively circular with eccentricities less than 0.04. The spin axis of the primary body and the orbital poles of both satellites are all aligned within about 2 deg of each other, indicating a nearly coplanar configuration and suggestive of satellite formation in or near the equatorial plane of the primary. We also investigate the past orbital evolution of the system by simulating the effects of a recent passage through 3:1 mean-motion eccentricity-type resonances. In some scenarios this allow us to place constraints on interior structure and past eccentricities.

  4. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    Energy Technology Data Exchange (ETDEWEB)

    Marrs, R


    In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many more satellites in orbit, and it is important to understand their vulnerability to radiation belt pumping from nuclear explosions at high altitude or in space. This report presents the results of a calculation of the contribution of neutron beta decay to artificial belt pumping. For most high altitude nuclear explosions, neutrons are expected to make a smaller contribution than fission products to the total trapped electron inventory, and their contribution is usually neglected. However, the neutron contribution may dominate in cases where the fission product contribution is suppressed due to the altitude or geomagnetic latitude of the nuclear explosion, and for regions of the radiation belts with field lines far from the detonation point. In any case, an accurate model of belt pumping from high altitude nuclear explosions, and a self-consistent explanation of the 1962 data, require inclusion of the neutron contribution. One recent analysis of satellite measurements of electron flux from the 1962 tests found that a better fit to the data is obtained if the neutron contribution to the trapped electron inventory was larger than that of the fission products [l]. Belt pumping from high altitude nuclear explosions is a complicated process. Fission fragments are dispersed as part of the ionized bomb debris, which is constrained and guided by the earth's magnetic field. Those fission products that beta decay before being lost to the earth's atmosphere can contribute trapped energetic electrons to the earth's radiation belts. There has been a large effort to develop computer models for

  5. Motion Track Modeling and Analysis of Belt Spindle under Combined Effects of Bending Moment-Torque-Thermal Deformation

    Institute of Scientific and Technical Information of China (English)

    齐向阳; 高卫国; 刘腾; 张大卫


    The motion track of belt spindle is important for the radial error of belt spindle. An analytical modeling method for the motion track of belt spindle under the combined effects of bending moment-torque-thermal deforma-tion is proposed in this paper. Three running phases of belt spindle have been analyzed and modeled:the start-up phase with leaping change due to the change in force and bending moment, the accelerating phase with axis deflection, and the constant speed phase with axis regression because of the combined effects of bending moment-torque-thermal de-formation. The simulation and test were completed on the belt spindle of SKVM850 machine tool, which illustrates the variation law of the radial error of belt spindle during the whole running phases.

  6. Innermost Van Allen Radiation Belt for High Energy Protons at Saturn (United States)

    Cooper, John F.


    The high energy proton radiation belts of Saturn are energetically dominated by the source from cosmic ray albedo neutron decay (CRAND), trapping of protons from beta decay of neutrons emitted from galactic cosmic ray nuclear interactions with the main rings. These belts were originally discovered in wide gaps between the A-ring, Janus/Epimetheus, Mimas, and Enceladus. The narrow F and G rings significant affected the CRAND protons but did not produce total depletion. Voyager 2 measurements subsequently revealed an outermost CRAND proton belt beyond Enceladus. Although the source rate is small, the trapping times limited by radial magnetospheric diffusion are very long, about ten years at peak measured flux inwards of the G ring, so large fluxes can accumulate unless otherwise limited in the trapping region by neutral gas, dust, and ring body interactions. One proposed final extension of the Cassini Orbiter mission would place perikrone in a 3000-km gap between the inner D ring and the upper atmosphere of Saturn. Experience with CRAND in the Earth's inner Van Allen proton belt suggests that a similar innermost belt might be found in this comparably wide region at Saturn. Radial dependence of magnetospheric diffusion, proximity to the ring neutron source, and northward magnetic offset of Saturn's magnetic equator from the ring plane could potentially produce peak fluxes several orders of magnitude higher than previously measured outside the main rings. Even brief passes through such an intense environment of highly penetrating protons would be a significant concern for spacecraft operations and science observations. Actual fluxes are limited by losses in Saturn's exospheric gas and in a dust environment likely comparable to that of the known CRAND proton belts. The first numerical model of this unexplored radiation belt is presented to determine limits on peak magnitude and radial profile of the proton flux distribution.

  7. Compliance with Use of Seat Belt among Commercial Drivers in a Nigerian Community

    Directory of Open Access Journals (Sweden)

    Oluwole C. Omolase


    Full Text Available AIM: This study aimed at determining compliance with use of seat belt among commercial intercity drivers. METHOD: This is a descriptive cross-sectional study conducted in Owo, South West Nigeria among commercial intercity drivers between June and September, 2009. Ethical clearance was obtained from the Ethical Review Committee of Federal Medical Centre, Owo, Ondo State, Nigeria prior to commencement of this study. The permission of the leadership of Road Transport Workers’ Union was also sought and obtained. Ninety intercity commercial drivers out of the estimated one hundred and sixty intercity commercial drivers in the community were enrolled in this study. Informed consent was obtained from each of the respondents. The data obtained was collated and analyzed with SPSS 15.0.1 statistical soft ware version. RESULTS: Ninety respondents were enrolled in this study. The driving experience of the respondents revealed that most respondents: 53 (58.9% had more than 20 years driving experience. Most respondents;78 (86.7% complied with use of seat belt .The main barrier to compliance with seat belt was short trip;28 (50.9%.Most respondents; 67 (74.4%were in support of penalization of defaulters. The major source of awareness about seat belt was Federal Road Safety Corps;59 (65.6%. CONCLUSION: Most respondents complied with use of seat belt. The major barrier to compliance with seat belt was short trip within the community. The Federal Road Safety Corps should enforce compliance with the use of seat belt most especially within communities. [TAF Prev Med Bull 2012; 11(3.000: 281-286

  8. Sm-Nd age of ultrabasite-basite massifs of east part of Baikal-Mujya ophiolite belt

    International Nuclear Information System (INIS)

    Two stratified ultrabasite-basite massifs of the Urals mountains were selected for isotope-geochemical studies. The intrusives, related to plutonic members of the island-arc associations, were used for dating. The Sm-Nd method indicated that one more belt, namely the Vend belt, is taking shape in the Baikal-Mujya tectonic collage alongside with the later Riphean (pre-Baikal) episubconduction belt of stratified intrusives

  9. Canonical Correlation Factors Causing the Formation of Accumulated Sand-belts along the Oasis Fringe in Hexi Corridor

    Institute of Scientific and Technical Information of China (English)

    Chang; Zhaofeng; Wang; Qiangqiang; Zhang; Jianhui; Tang; Jinnian; Zhu; Shujuan; Fan; Baoli; Zhang; Dabiao; Liu; Shizeng; Zhang; Guozhong; Li; Aide


    Accumulated sand-belts refer to those formed along the oasis fringe,especially at the upwind location,due to the accumulation of sand blocked by farmland windbreak. In the 60 years since the foundation of new China,a lot of trees have been planted for desertification combating in northwest and north China,thus,accumulated sand-belts were formed at the upwind location. The formation and the ecological effects of the accumulated sand-belts along the oasis fringe is a new scientific concern. To study the formation causes of these belts in Hexi corridor,21 samples were selected,and the height / width of the belts,as well as the vegetation,soil,soil moisture and climatic factors were investigated. This paper analyzed the correlation between the height / width of the belts and the vegetation,soil,soil moisture and climatic factors using the methods of variance analysis,correlation analysis and canonical correlation analysis. The results indicate that: the accumulated sand-belts take a trend of being high and wide in the east whereas low and narrow in the west,and most of the parts tend to be stable; the species on the belts are dominated by Tamarix austromongolica,the vegetation cover and the pure vegetation cover of different dominant species on the leeward slope of the accumulated sand-belts vary significantly. The canonical correlation analysis shows that: the height and width of accumulated sand-belt is the interaction of precipitation,distance to the sand source,leeward vegetation cover and annual average wind speed. Moreover,the height of accumulated sand-belts are negatively correlated to the soil moisture at the depth of 30- 50 cm,air humidity and leeward vegetation cover,and the width of the belts is also negatively correlated with the distance to the sand source. The ecological effects of the accumulated sand-belts are both positive( stopping sands from moving into farmland,protective role as an obstacle)and negative( when the belts decay and activate one day

  10. Rear seat belt use as an indicator of safe road behaviour in a rapidly developing country. (United States)

    McIlvenny, Shirley; Al Mahrouqi, Fatma; Al Busaidi, Thuraiya; Al Nabhani, Ahmed; Al Hikmani, Fatma; Al Kharousi, Zaher; Al Mammari, Salima; Al Hoti, Anwaral; Al Shihi, Aysha; Al Lawati, Anwar; Al Kharousi, Ibtisam


    Injuries from road traffic accidents are set to become the second highest cause of disability-adjusted life years lost in developing countries by 2020. The number of injuries and deaths are disproportionately high in low income countries, which account for only 40% of all motor vehicles. Human behaviour is thought to be a major factor in most accidents. In Oman wearing a seat belt is compulsory in the front seats but not in the rear. Wearing a seat belt can reduce the severity of injuries when sitting in rear seats. This study examines the use of seat belts in cars entering a university and hospital campus in Oman to determine the degree of seat belt wearing in the rear. At peak times on a selected day, cars were stopped at the university's entrance barrier. The type of driver was identified - student, employee, hospital patient or visitor - and the degree of seat belt wearing among driver and passengers was noted. A total of 1,066 cars were stopped. Of this total, 90.1% of drivers and 80.9% of front seat passengers were wearing a restraint complying with Local traffic regulations. However, only 1.4% of back seat passengers wore a seat belt. Only 3.7% of children under the age of five were restrained in a child seat and only 16.7% of five- to 12-year-olds were strapped in. A third (34.6%) of under-fives were sitting in the front seat. In cars with child occupants, 40% of the time parents wore seat belts but the children did not. Occupants conformed to the law but behaviour indicated a lack of awareness of the dangers of not wearing seat belts, especially towards children. Traffic regulations need to be updated and the public educated about the need to wear seat belts. Health agencies could be more active in educating the public about road safety behaviour and should also be involved in the overall strategy to reduce injuries and deaths. PMID:15602998

  11. Modelling the outer radiation belt as a complex system in a self-organised critical state

    Directory of Open Access Journals (Sweden)

    N. B. Crosby


    Full Text Available The dynamic behaviour of the outer electron radiation belt makes this area of geo-space a candidate for the concept of self-organized criticality. It is shown here that frequency distributions of measured outer electron radiation belt data are well-represented by power-laws over two decades. Applying the concept of self-organized criticality to interpret the shape of the distributions suggests another approach to complement existing methods in the interpretation of how this complicated environment works. Furthermore sub-grouping the radiation belt count rate data as a function of spatial location or temporal interval (e.g. L-shell, magnetic local time, solar cycle, ... shows systematic trends in the value of the slope of the power-laws. It is shown that the inner part of the outer radiation belt is influenced in a similar manner to the outer part, but in a less profound way. Our results suggest that the entire outer radiation belt appears to be affected as the sum of its individual parts. This type of study also gives the probability of exceeding a given threshold value over a given time; limiting the size of 'an event'. The average values could then be compared with models used in spacecraft design.

  12. The impact of radiation belts region on top side ionosphere condition during last solar minimum. (United States)

    Rothkaehl, Hanna; Przepiórka, Dororta; Matyjasiak, Barbara


    The wave particle interactions in radiation belts region are one of the key parameters in understanding the global physical processes which govern the near Earth environment. The populations of outer radiation belts electrons increasing in response to changes in the solar wind and the interplanetary magnetic field, and decreasing as a result of scattering into the loss cone and subsequent absorption by the atmosphere. The most important question in relation to understanding the physical processes in radiation belts region relates to estimate the ratio between acceleration and loss processes. This can be also very useful for construct adequate models adopted in Space Weather program. Moreover the wave particle interaction in inner radiation zone and in outer radiation zone have significant influence on the space plasma property at ionospheric altitude. The aim of this presentation is to show the manifestation of radiation belts region at the top side ionosphere during the last long solar minimum. The presentation of longitude and seasonal changes of plasma parameters affected by process occurred in radiation belts region has been performed on the base of the DEMETER and COSMIC 3 satellite registration. This research is partly supported by grant O N517 418440

  13. Regional evaluation of the hydrocarbon potential for the South American thrust belts and adjacent foreland basins

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J.; Cook, J.; Davis, M.; Eggers, L.; Spencer, S.; Toadvine, S. [Amoco Worldwide Exploration Business Group, Houston, TX (United States)


    The hydrocarbon potential of the Andean thrust belts and adjacent foreland basins is varied and made complicated by regional-scale changes in stratigraphy and accompanying structural style. These changes appear to be controlled by an inherited Paleozoic structural grain and an early Mesozoic rifting fabric. Accompanying these factors are variations in source rock and evaporate distribution. Understanding the variability in the exploration and exploitation potential of the Andes is facilitated by a comparison with other thrust and fold belts from around the world. Using an integrated, modular approach, we have analyzed 27 petroliferous thrust belts and adjacent foreland basins from around the world to study the wide variety within these petroleum systems and their associated geotechnical risks. This global study indicates that the essential factors of productive systems are the volume and distribution of effective source rocks in conjunction with the timing of hydrocarbon generation, migration, and entrapment. This timing varies extensively from north to south. Hence, what works in one portion of the belt may not work in another. Integration of a global study of well-documented thrust belts and foreland basins systems with an Andean exploration or exploitation study helps narrow the range of possible interpretations developed from minimal data commonly available prior to bid rounds. It also helps in field exploitation and deeper pool wildcat exploration by suggesting new trap type potential.

  14. STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the Orbit of Fomalhaut b

    CERN Document Server

    Kalas, Paul; Fitzgerald, Michael P; Clampin, Mark


    We present new optical coronagraphic data of the bright star Fomalhaut obtained with the HST in 2010/2012 using STIS. Fomalhaut b is recovered at both epochs to high significance. The observations include the discoveries of tenuous nebulosity beyond the main dust belt detected to at least 209 AU projected radius and a ~50 AU wide azimuthal gap in the belt northward of Fom b. The morphology of Fomalhaut b appears elliptical in the STIS detections. We show that residual noise in the processed data can plausibly result in point sources appearing extended. A MCMC analysis demonstrates that the orbit of Fom b is highly eccentric, with e=0.8+/-0.1, a=177+/-68 AU, and q = 32+/-24 AU. Fom b is apsidally aligned with the belt and 90% of allowed orbits have mutual inclination 36 deg or less. Fomalhaut b's orbit is belt-crossing in projection, but only 12% of possible orbits have nodes within a 25 AU wide belt annulus (133-158 AU). The high e invokes a dynamical history where Fom b may have experienced a significant dyn...

  15. Research on Magnetic Model of Low Resistance Permanent Magnet Pipe Belt Conveyor (United States)

    Wang, Shuang; Li, De-yong; Guo, Yong-cun


    In view of the feasibility of a new type of low resistance permanent magnet pipe belt conveyor, the magnetic properties of the permanent magnet magnetic pipe conveyor belt system are studied. Based on the molecular current hypothesis, the mathematical model of the three dimensional radial magnetic force of permanent magnet pipe conveyor belt was established. The mathematical model of the radial magnetic force was derived, and the influence factors of the radial magnetic force were derived. The finite element simulation of permanent magnet-magnetic pipe conveyor belt magnetic model was carried out, then the magnetic flux density distribution chart under the conditions of different remanence intensity of different permanent magnet and different lengths of the permanent magnets (along the transport direction) were obtained. The simulation results are consistent with the calculation results, which shows that the permanent magnet pipe belt conveyor is feasible. Under certain conditions, the radial magnetic force has nonlinear increase relations with residual magnetism of permanent magnet and the length of the permanent magnet (along the transport direction).

  16. Simulation of ULF wave-modulated radiation belt electron precipitation during the 17 March 2013 storm (United States)

    Brito, T.; Hudson, M. K.; Kress, B.; Paral, J.; Halford, A.; Millan, R.; Usanova, M.


    Balloon-borne instruments detecting radiation belt precipitation frequently observe oscillations in the millihertz frequency range. Balloons measuring electron precipitation near the poles in the 100 keV to 2.5 MeV energy range, including the MAXIS, MINIS, and most recently the Balloon Array for Relativistic Radiation belt Electron Losses balloon experiments, have observed this modulation at ULF wave frequencies. Although ULF waves in the magnetosphere are seldom directly linked to increases in electron precipitation since their oscillation periods are much larger than the gyroperiod and the bounce period of radiation belt electrons, test particle simulations show that this interaction is possible. Three-dimensional simulations of radiation belt electrons were performed to investigate the effect of ULF waves on precipitation. The simulations track the behavior of energetic electrons near the loss cone, using guiding center techniques, coupled with an MHD simulation of the magnetosphere, using the Lyon-Fedder-Mobarry code, during a coronal mass ejection (CME)-shock event on 17 March 2013. Results indicate that ULF modulation of precipitation occurs even without the presence of electromagnetic ion cyclotron waves, which are not resolved in the MHD simulation. The arrival of a strong CME-shock, such as the one simulated, disrupts the electric and magnetic fields in the magnetosphere and causes significant changes in both components of momentum, pitch angle, and L shell of radiation belt electrons, which may cause them to precipitate into the loss cone.

  17. Studies on the evaluation of thermal belts and radiation fog over mountainous regions by LANDSAT data

    International Nuclear Information System (INIS)

    Local meteorological phenomena and characteristics under conditions of nocturnal radiative cooling in winter were investigated using Landsat data and physiographic parameters over the hilly and mountainous regions of the western part of shikoku. (1) Relative elevation between thermal belts and underlying ground such as bottom of basin or valley was 400m on an average. (2) Thermal belts appeared in the zone between 400m and 1000m above the sea level in the western part of Shikoku. (3) Temperature of the thermal belts varied with the elevation in a ratio of about 1 degrees C/100m. This observation indicated that the thermal belt temperature was closely related to the altitude of the zone where the thermal belts originated. (4) Radiation fog was frequently recorded over some part along the Hiji river and over the area along Ootoyo to Motoyama; fog was present even at 10 a.m. (3 hours after sunrise). (5) Upper surface of the fog layer was located at 200m and 600m above the sea level in the Oozu basin and in the area along Ootoyo to Motoyama respectively. (6) In the Oozu basin, the distribution of hamlets on the mountainside was often recognized in the localities within the upper limit of foggy areas

  18. NEP for a Kuiper Belt Object Rendezvous Mission

    International Nuclear Information System (INIS)

    Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total ΔV of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All

  19. Geoinformatics and Data Fusion in the Southwestern Utah Mineral Belt (United States)

    Kiesel, T.; Enright, R.


    Data Fusion is a technique in remote sensing that combines separate geophysical data sets from different platforms to yield the maximum information of each set. Data fusion was employed on multiple sources of data for the purposes of investigating an area of the Utah Mineral Belt known as the San Francisco Mining District. In the past many mineral deposits were expressed in or on the immediate surface and therefore relatively easy to locate. More modern methods of investigation look for evidence beyond the visible spectrum to find patterns that predict the presence of deeply buried mineral deposits. The methods used in this study employed measurements of reflectivity or emissivity features in the infrared portion of the electromagnetic spectrum for different materials, elevation data collected from the Shuttle Radar Topography Mission and indirect measurement of the magnetic or mass properties of deposits. The measurements were collected by various spaceborne remote sensing instruments like Landsat TM, ASTER and Hyperion and ground-based statewide geophysical surveys. ASTER's shortwave infrared bands, that have been calibrated to surface reflectance using the atmospheric correction tool FLAASH, can be used to identify products of hydrothermal alteration like kaolinite, alunite, limonite and pyrophyllite using image spectroscopy. The thermal infrared bands once calibrated to emissivity can be used to differentiate between felsic, mafic and carbonate rock units for the purposes of lithologic mapping. To validate results from the extracted spectral profiles existing geological reports were used for ground truth data. Measurements of electromagnetic spectra can only reveal the composition of surface features. Gravimetric and magnetic information were utilized to reveal subsurface features. Using Bouguer anomaly data provided by the USGS an interpreted geological cross section can be created that indicates the shape of local igneous intrusions and the depth of

  20. Lithospheric seismic fabrics of Sulu ultrahigh-pressure metamorphic belt

    Institute of Scientific and Technical Information of China (English)

    YANG; Wencai; YANG; Wuyang; JIN; Zhenmin; CHENG; Zhenyan


    Calibration of seismic reflectors appearing in the crust of the Chinese continent scientific drilling site can be completed through the correlation studies between direct evidences, such as the drill cores, and geophysical signatures; therefore the interpretation of geophysical data could produce reliable results of crustal structure and composition. On the other hand, there are two Cenozoic volcanoes close to the scientific drilling site; analyzing composition of xenoliths existent in the volcanoes and evaluating their seismic velocities can also offer information about the mantle and lower crust. After the calibration via cores and well-logging data, the seismic reflectors appearing in the UHP belt can be caused by lithological changes within the UHP rock slice, ductile shearing rock-suites, and later fracture zones. Among these sources, ductile shearing resulted in displacement and detachment of original rock-sheets, producing some rock-interbeds of several hundred meters thick that are named the ductile shearing rock-suites. A suite consists of mylonized gneiss and eclogite slices that underwent shearing, becoming the major mechanism responsible to generate regional strong reflections. The UHP rock-slice is characterized by complicated structures and high density, high seismic velocity and high electrical resistivity, its thickness is usually less than 11 km. Velocity and density of the gneiss-layer beneath gradually tend to normal with increasing depth. Based on the xenoliths we can infer that the middle crust contains a lot of gneisses, and the lower crust consists of different granulites. The lithospheric mantle has multi-layer structures and consists mainly of spinal lherzolite and harzburgite, implying late Mesozoic lithospheric thinning. The seismic fabrics with different origins were possible products of different geodynamic processes. For instance, the UHP rock-slice was produced by the UHP metamorphic process and the exhumation of subducted


    Directory of Open Access Journals (Sweden)

    Manoel Cléber de Sampaio Alves


    Full Text Available The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size on the output parameters (temperature and surface roughness for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD. The results were analyzed employing the analysis of variance (ANOVA with 5% of significance level. Only grit sizes were significant to different temperature levels. The same outcome was observed for roughness, where only grits sizes were significant. No interaction between the pressure and belt speed factors were observed for all the results analyzed.

  2. New developments in Orinoco oil belt projects reflect a positive effect on the areas reserves

    Energy Technology Data Exchange (ETDEWEB)

    Villarroel, T. [PDVSA, La Campina, Caracas (Venezuela)


    The Orinoco oil belt is located in the eastern Venezuela basin, parallel to the Orinoco River. The area is divided into four zones which include four projects that convert crude oil to synthetic crudes. Petroleos de Venezuela S.A. (PDVSA) believes that the extra heavy oil reserve scenario of this area is extremely promising. This paper discussed several positive effects that recent developments have had on the reserve numbers within the area. Reserve numbers of the five joint venture projects currently operating in the area were presented. The paper discussed the location of the Orinoco oil belt and presented the general geology of the region. Basic reservoir properties and ongoing projects in the Orinoco heavy oil belt were described. Production methods for extra heavy oils were also explained. It was concluded that huge investment opportunities existed in the area, especially for those interested in participating in mixed enterprises with the Venezuelan government. 6 refs., 16 figs.

  3. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction

    Directory of Open Access Journals (Sweden)

    Rebecca Gyawu


    Full Text Available In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%, restaurants (19.7%, fast food restaurants (16.4%, small supermarkets (8.2%, and large supermarket and farmers' markets (3.3 %, respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p < 0.0001 higher health scores than the other store types. A few health promotion messages were highly visible or obscurely positioned in some RFOs. The Alabama Black Belt food environment had limited opportunities for healthy food choices.

  4. Using Intermediate-Luminosity Optical Transients (ILOTs) to reveal extended exo-solar Kuiper belt objects

    CERN Document Server

    Bear, Ealeal


    We suggest that in the rare case of an Intermediate-Luminosity Optical Transient (ILOTs) event, evaporation of exo-solar Kuiper belt objects (ExoKBOs) at distances of d~500 - 10000AU from the ILOT can be detected. If the ILOT lasts for 1 month to a few years, enough dust might be ejected from the ExoKBOs for the IR emission to be detected. Because of the large distance of the ExoKBOs, tens of years will pass before the ILOT wind disperses the dust. We suggest that after an ILOT outburst there is a period of months to several years during which IR excess emission might hint at the existence of a Kuiper belt analog (ExoK-Belt).

  5. Design of belt conveyor electric control device based on CC-link bus (United States)

    Chen, Goufen; Zhan, Minhua; Li, Jiehua


    In view of problem of the existing coal mine belt conveyor is no field bus communication function, two levels belt conveyor electric control system design is proposed based on field bus. Two-stage belt conveyor electric control system consists of operation platform, PLC control unit, various sensors, alarm device and the water spraying device. The error protection is realized by PLC programming, made use of CC-Link bus technology, the data share and the cooperative control came true between host station and slave station. The real-time monitor was achieved by the touch screen program. Practical application shows that the system can ensure the coalmine production, and improve the automatic level of the coalmine transport equipment.

  6. Gas Phase Growth of Wurtzite ZnS Nano belts on a Large Scale

    International Nuclear Information System (INIS)

    We showed large-scale synthesis of ZnS nano belts by simply thermal evaporation of ZnS powder in the presence of Au catalysts at 1020°C. Scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) analyses demonstrated that the as-obtained ZnS nano belts possess hexagonal wurtzite structures. The nano belts have lengths ranging from tens to hundreds of micrometers, thicknesses of tens of nanometers, and widths ranging from hundreds of nanometers to the order of micrometers. The growth process was proposed on the basis of known vapor-liquid-solid (VLS) mechanism. Room temperature photoluminescence measurements showed that the as-synthesized ZnS nano structures had a strong green emission bands at a wavelength of 427 nm, which can be attributed to deep-level emissions induced by defects or impurities.

  7. [Traumatic dissection of the internal carotid artery by a safety belt: a report of two cases]. (United States)

    López-Sánchez, M; Ballesteros-Sanz, M A; Pérez-Ceballos, A; González-Fernández, C; López-Espadas, F


    Traumatic internal carotid artery dissection secondary to blunt trauma is a rare event accounting for 0.08 to 0.4% of all traumatic lesions. The spectrum of traumatic lesions that can affect the internal carotid artery includes minor lesions like spasm, intimal tears, or mural contusions and serious lesions like pseudoaneurysms and complete occlusion. Delayed clinical presentation is typical and can include headache, hemiparesis, partial Horner's syndrome, and cranial nerve palsy. Embolization secondary to the dissection can have devastating effects because it may cause ischemic stroke. Traumatic internal carotid artery dissection after safety belt trauma is very rare; it is usually due to direct cervical trauma on the side of the shoulder fixation point, which causes external bruising along the pathway of the safety belt. We present two cases of traumatic internal carotid artery dissection with concomitant cerebral infarcts caused by safety belts; we discuss the clinical, diagnostic, and therapeutic aspects of this lesion. PMID:19828398

  8. Drying of HTR fissile and fertile particles and experience with a belt dryer

    International Nuclear Information System (INIS)

    In the fabrication of fissile and fertile material particles for high-temperature reactors, drying of the gel particles is a very important process step. First, the drying properties of ThO2(Th, U)O2 and UO2 gel particles were examined and a belt dryer for continuous drying was developed using the findings obtained. The parameters during examination of the drying properties were: Th/U ratio, content of organic accessory substances, residual concentration of ammonium nitrate, particle size, washing liquid, ageing and drying room atmosphere. The belt dryer developed, having a centre-to-centre distance of 2.5 m and a belt width of 350 mm, can be used for drying approx. 0.8 kg/h of heavy metal oxide particles. The particle residence time in the dryer is only 8 to 13 minutes. (orig.)

  9. Properties of Hermean plasma belt: Numerical simulations and comparison with MESSENGER data (United States)

    Herčík, David; Trávníček, Pavel M.; Å tverák, Å. těpán.; Hellinger, Petr


    Using a global hybrid model and test particle simulations we present a detailed analysis of the Hermean plasma belt structure. We investigate characteristic properties of quasi-trapped particle population characteristics and its behavior under different orientations of the interplanetary magnetic field. The plasma belt region is constantly supplied with solar wind protons via magnetospheric flanks and tail current sheet region. Protons inside the plasma belt region are quasi-trapped in the magnetic field of Mercury and perform westward drift along the planet. This region is well separated by a magnetic shell and has higher average temperatures and lower bulk proton current densities than the surrounding area. On the dayside the population exhibits loss cone distribution function matching the theoretical loss cone angle. The simulation results are in good agreement with in situ observations of MESSENGER's (MErcury Surface Space ENvironment GEochemistry, and Ranging) MAG and FIPS instruments.

  10. Progress on the Size Frequency Distribution of Small Main-belt Asteroids (United States)

    Burt, Brian; Trilling, D. E.; Hines, D. C.; Stapelfeldt, K. R.; Rebull, L. M.; Fuentes, C. I.; Hulsebus, A.


    The asteroid size distribution informs us about the formation and composition of the Solar System. We build on our previous work in which we harvest serendipitously obtained Spitzer data of the Taurus region and measure the brightness and size distributions of Main-belt asteroids. This is accomplished with the highly sensitive MIPS 24 micron channel. We expect to catalog 104 asteroids, giving us a statistically significant data set. Results from this investigation will allow us to characterize the total population of small, Main-belt asteroids. Here we will present new results on the completeness of our study and the presence of size distribution variations with inclination and radial distance in the belt. We acknowledge and thank funding from PMDAP through NASA.

  11. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction. (United States)

    Gyawu, Rebecca; Quansah, Joseph E; Fall, Souleymane; Gichuhi, Peter N; Bovell-Benjamin, Adelia C


    In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs) were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%), restaurants (19.7%), fast food restaurants (16.4%), small supermarkets (8.2%), and large supermarket and farmers' markets (3.3 %), respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p < 0.0001) higher health scores than the other store types. A few health promotion messages were highly visible or obscurely positioned in some RFOs. The Alabama Black Belt food environment had limited opportunities for healthy food choices. PMID:26844138

  12. RCM-VERB coupled simulations of the dynamics of the radiation belts during storms

    International Nuclear Information System (INIS)

    Complete text of publication follows. The evolution of the relativistic electron fluxes in the radiation belts can be described by the 3D modified Fokker-Planck equation in terms of radial distance, pitch-angle, and energy. Recently developed at UCLA VERB code models the dynamics of relativistic electrons subjected to ULF, ELF, and VLF waves including radial diffusion driven by PC4-5 waves; pitch-angle scattering by hiss, chorus, anthropogenic whistlers, lightning generated whistlers, and EMIC waves; and local acceleration driven by chorus waves. Numerical simulations of a geomagnetic storm using VERB code, coupled with RCM are presented. Dynamics of the 10-100 keV electrons is inferred from RCM simulations and is used as an electrons seed population for the radiation belts modeling using VERB code. Presented sensitivity numerical simulations show the influence of the time-dependent convective sources on the radiation belt dynamics.

  13. Triple junction orogeny: tectonic evolution of the Pan-African Northern Damara Belt, Namibia (United States)

    Lehmann, Jérémie; Saalmann, Kerstin; Naydenov, Kalin V.; Milani, Lorenzo; Charlesworth, Eugene G.; Kinnaird, Judith A.; Frei, Dirk; Kramers, Jan D.; Zwingmann, Horst


    Trench-trench-trench triple junctions are generally geometrically and kinematically unstable and therefore can result at the latest stages in complicated collisional orogenic belts. In such geodynamic sites, mechanism and timescale of deformations that accommodate convergence and final assembly of the three colliding continental plates are poorly studied. In western Namibia, Pan-African convergence of three cratonic blocks led to pene-contemporaneous closure of two highly oblique oceanic domains and formation of the triple junction Damara Orogen where the NE-striking Damara Belt abuts to the west against the NNW-striking Kaoko-Gariep Belt. Detailed description of structures and microstructures associated with remote sensing analysis, and dating of individual deformation events by means of K-Ar, Ar-Ar (micas) and U-Pb (zircon) isotopic studies from the Northern Damara Belt provide robust constraints on the tectonic evolution of this palaeo-triple junction orogeny. There, passive margin sequences of the Neoproterozoic ocean were polydeformed and polymetamorphosed to the biotite zone of the greenschist facies to up to granulite facies and anatexis towards the southern migmatitic core of the Central Damara Belt. Subtle relict structures and fold pattern analyses reveal the existence of an early D1 N-S shortening event, tentatively dated between ~635 Ma and ~580 Ma using published data. D1 structures were almost obliterated by pervasive and major D2 E-W coaxial shortening, related to the closure of the Kaoko-Gariep oceanic domain and subsequent formation of the NNW-striking Kaoko-Gariep Belt to the west of the study area. Early, km-scale D1 E-W trending steep folds were refolded during this D2 event, producing either Type I or Type II fold interference patterns visible from space. The D2 E-W convergence could have lasted until ~533 Ma based on published and new U-Pb ages. The final D3 NW-SE convergence in the northernmost Damara Belt produced a NE-striking deformation

  14. Atmospheres and surfaces of small bodies and dwarf planets in the Kuiper Belt

    Directory of Open Access Journals (Sweden)

    Schaller E.L.


    Full Text Available Kuiper Belt Objects (KBOs are icy relics orbiting the sun beyond Neptune left over from the planetary accretion disk. These bodies act as unique tracers of the chemical, thermal, and dynamical history of our solar system. Over 1000 Kuiper Belt Objects (KBOs and centaurs (objects with perihelia between the giant planets have been discovered over the past two decades. While the vast majority of these objects are small ( 6-meter telescopes, have allowed for the first detailed studies of their surfaces and atmospheres. Visible and near-infrared spectroscopy of KBOs and centaurs has revealed a great diversity of surface compositions. Only the largest and coldest objects are capable of retaining volatile ices and atmospheres. Knowledge of the dynamics, physical properties, and collisional history of objects in the Kuiper belt is important for understanding solar system formation and evolution.

  15. Tyre/road interaction noise—A 3D viscoelastic multilayer model of a tyre belt (United States)

    O'Boy, D. J.; Dowling, A. P.


    Vehicle noise is an increasing local environmental problem. For cars, above a steady speed of 40 km/h the noise produced by the interaction of the tyres with the road surface is the dominant noise source. In order to be able to predict this noise, the vibration characteristics of a stationary tyre must be determined. A multilayer viscoelastic cylindrical representation of the tyre belt, located between the sidewalls of the tyre and excluding the tread, is provided which yields the displacement and velocity response of the tyre belt when excited in the radial or tangential directions for a wide range of excitation frequencies, using only data from the design process. This model includes a representation of an air cavity and sidewalls and the response of the tyre belt is determined in both the frequency-wavenumber and time-spatial domains. The model can then be used to determine the noise of a tyre rolling on a rough road.

  16. Trapping in stochastic mechanics and applications to covers of clouds and radiation belts

    International Nuclear Information System (INIS)

    It is possible to assign a stochastic acceleration to conservative stochastic diffusion processes. As a basic assumption, this stochastic acceleration is set equal to the deterministic smooth component of the external force acting on the particle, whereas the influences of the remainder is modelled by a diffusion coefficient. In this paper, we shall try to see whether it can account for the observation in two cases: the cover of clouds of planets and the radiation belts in the planetary magnetic field. We describe the basic properties of Newtonian Diffusion Stochastic Processes and indicate their connection with Schroedinger-like equations. Furthermore we give a heuristic interpretation of the nodal surfaces as impenetrable barriers for Newtonian Stochastic Diffusion Processes. The possible applications to the observed average cloud covering in the planetary atmosphere are presented we discuss the radiation belts (Van Allen Belts) along the previous ideas


    Institute of Scientific and Technical Information of China (English)

    刘志河; 张海涛; 绍庆龙


    Electromagnetic self-induction theory and computer are adopted and study of online monitoring technique for wire-core belt is conducted, the study shows that there is direct proportion between distance I of broken ends and output volt V, when I≥60 mm, V keeps constantly, the running speed v of wire-core belt has no big effect on output volt V, there is inverse proportion between the height h from probe to the surface of the belt and output volt V, when h≥30mm, V tends to be zero. Based on the test result, on-line monitoring installation is developed, the practice proved that the accuracy of broken wire monitoring can be above 95%, the monitoring accuracy of joint twitch can be 0.04 V/mm.

  18. Some problems of geologic relations between the Amazon craton and east margins fold belts

    International Nuclear Information System (INIS)

    This paper deals with some geologic problems related to the limits between the Amazon craton and the fold belts developed at its margins during the Precambrian. These limits are diversified but clearly recognized. To the north, the Araguaia-Tocantins fold belt, of presumed Middle Proterozoic age, is separated from the cratonic block by a deep marginal fracture zone permeated by mafic and ultramafic rocks. The geologic, magmatic and aeromagnetic characteristics of this zone point out the presence of deep faults, supposed to be of Middle Proterozoic age. The southern Paraguay fold belt constitutes and accurated zone of linear structures supposed to be of Late Proterozoic development. Despite the great increase of knowledge during the last ten years many tectonic, stratigraphic and geochronologic problems remain unsolved. The aim of this paper is to point out some of these problems and suggest specific studies to solve them. (author)

  19. Growth of asteroids, planetary embryos and Kuiper belt objects by chondrule accretion

    CERN Document Server

    Johansen, Anders; Lacerda, Pedro; Bizzarro, Martin


    Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas-drag-assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo run-away accretion of chondrules within ~3 Myr, forming planetary embryos up to Mars sizes along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size-sorting of chondrules consistent with chondrites. Accretion of mm-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disk life time outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is...

  20. Centennial variations in sunspot number, open solar flux and streamer belt width: 3. Modeling (United States)

    Lockwood, M.; Owens, M. J.


    From the variation of near-Earth interplanetary conditions, reconstructed for the mid-19th century to the present day using historic geomagnetic activity observations, Lockwood and Owens (2014) have suggested that Earth remains within a broadened streamer belt during solar cycles when the Open Solar Flux (OSF) is low. From this they propose that the Earth was immersed in almost constant slow solar wind during the Maunder minimum (c. 1650-1710). In this paper, we extend continuity modeling of the OSF to predict the streamer belt width using both group sunspot numbers and corrected international sunspot numbers to quantify the emergence rate of new OSF. The results support the idea that the solar wind at Earth was persistently slow during the Maunder minimum because the streamer belt was broad.