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71.
72.
Roman Tomaschitz 《Astrophysics and Space Science》2000,271(2):181-203
A pre-relativistic cosmological approach to electromagnetism and gravitation is explored that leads to a cosmic time variation
of the fundamental constants. Space itself is supposed to have physical substance, which manifests by its permeability. The
scale factors of the permeability tensor induce a time variation of the fundamental constants. Atomic radii, periods, and
energy levels scale in cosmic time, which results in dispersionless redshifts without invoking a space expansion. Hubble constant
and deceleration parameter are reviewed in this context. The time variation of the gravitational constant at the present epoch
can be expressed in terms of these quantities. This provides a completely new way to restrain the deceleration parameter from
laboratory bounds on the time variation of the gravitational constant. This variation also affects the redshift dependence
of angular diameters and the surface brightness, and we study in some detail the redshift scaling of the linear sizes of radio
sources. The effect of the varying constants on source counts is discussed, and an estimate on the curvature radius of the
hyperbolic3-space is inferred from the peak in the quasar distribution. The background radiation in this dispersionless, permeable
space-time stays perfectly Planckian. Cosmic time is discussed in terms of atomic and gravitational clocks, as well as cosmological
age dating, in particular how the age of the Universe relates to the age of the Galaxy in a permeable space-time.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
73.
Multiple re‐advances of a Lake Vättern outlet glacier during Fennoscandian Ice Sheet retreat,south‐central Sweden
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Sarah L. Greenwood Matt O'Regan Henrik Swärd Tom Flodén Roman Ananyev Denis Chernykh Martin Jakobsson 《Boreas: An International Journal of Quaternary Research》2015,44(4):619-637
Lake Vättern represents a critical region geographically and dynamically in the deglaciation of the Fennoscandian Ice Sheet. The outlet glacier that occupied the basin and its behaviour during ice‐sheet retreat were key to the development and drainage of the Baltic Ice Lake, dammed just west of the basin, yet its geometry, extent, thickness, margin dynamics, timing and sensitivity to regional retreat forcing are rather poorly known. The submerged sediment archives of Lake Vättern represent a missing component of the regional Swedish deglaciation history. Newly collected geophysical data, including high‐resolution multibeam bathymetry of the lake floor and seismic reflection profiles of southern Lake Vättern, are used here together with a unique 74‐m sediment record recently acquired by drill coring, and with onshore LiDAR‐based geomorphological analysis, to investigate the deglacial environments and dynamics in the basin and its terrestrial environs. Five stratigraphical units comprise a thick subglacial package attributed to the last glacial period (and probably earlier), and an overlying >120‐m deglacial sequence. Three distinct retreat–re‐advance episodes occurred in southern Lake Vättern between the initial deglaciation and the Younger Dryas. In the most recent of these, ice overrode proglacial lake sediments and re‐advanced from north of Visingsö to the southern reaches of the lake, where ice up to 400 m thick encroached on land in a lobate fashion, moulding crag‐and‐tail lineations and depositing till above earlier glacifluvial sediments. This event precedes the Younger Dryas, which our data reveal was probably restricted to north‐central sectors of the basin. These dynamics, and their position within the regional retreat chronology, indicate a highly active ice margin during deglaciation, with retreat rates on average 175 m a?1. The pronounced topography of the Vättern basin and its deep proglacial‐dammed lake are likely to have encouraged the dynamic behaviour of this major Fennoscandian outlet glacier. 相似文献
74.
75.
Seasonal meteorological events of high wind energy are important in the export of organic carbon from Biscayne Bay, Florida, by altering circulation and tidal flushing patterns coincident with increased resuspension. The accumulation of detrital organic carbon in the bay during productive summer months with light south-east breezes is reversed by the onset of the winter season and associated weekly cold fronts with sustained 15 knot northerly winds. The reversal of Biscayne Bay circulation patterns and increased discharge at Caesar's Creek result in an outwelling of dissolved organic carbon and particulate organic carbon. Southward advection at the seaward extremes of exchange channels prevents reintroduction of exported organic carbon by tidal currents. 相似文献
76.
Roman U. Sexl Hannelore Sexl Hanns Stremnitzer Donald G. Burkhard 《Earth, Moon, and Planets》1971,3(2):189-213
A theory of the directional characteristics of the lunar infrared radiation measured by Saari and Shorthill has been derived. This theory is in excellent agreement with experiment at all angles of observation and at all phase angles. The radiation law used to describe the angular dependence of the infrared radiation emitted by a flat element of the lunar surface is 0.85 cos + 0.22 cos2, where is the angle between the surface normal and the direction of observation. This radiation law is subsequently modified by taking into account lunar surface roughness. We assume a surface covered in part with spherical craters of various depth to diameter ratios as a model for the lunar soil. Re-radiation within the craters has been accounted for. Extensive use is made of group theoretical and invariant tensor methods which enable us to show that most of the details of the radiation pattern do not depend on the detailed nature of the surface features assumed, but only on the average surface slope. A best fit to the Saari-Shorthill data has been obtained by assuming 50% of the lunar surface to be covered with craters with a depth to diameter ratio of 1:3, while the remainder of the surface is essentially flat. The mean deviation between theory and experiment is 4K.This work has been supported by the National Aeronautics and Space Administration under Contracts No. NAS8-20 385 and NAS8-25 585, Marshall Space Flight Center, Alabama.Receipt delayed due to postal strike in Great Britain. 相似文献
77.
Riccardo Albertoni Monica De Martino Paola Podestà Andreas Abecker Roman Wössner Karsten Schnitter 《Earth Science Informatics》2018,11(4):525-544
The paper illustrates a Linked Thesaurus Framework for the Environment, named LusTRE, to facilitate data sharing across different environmental disciplines. It provides a knowledge infrastructure of multilingual thesauri and code lists, interlinking them so that they can be used as one integrated linked data source. This multilingual thesaurus is published according to the Linked Data Best Practices and supports metadata compilation and data discovery for describing and finding Environmental geodata. A human readable web interface is provided for the exploitation of LusTRE as well as a set of web services for programmatic access to the knowledge infrastructure. LusTRE has been exploited within the European directive INSPIRE and SEIS piloting testbeds implemented within the EU project eENVplus in order to support cross-border and cross-domain data sharing. It is aimed at supporting multilingual data search and query refinement. In order to show how interlinked content can help users to more easily express metadata within Spatial Data Infrastructures (SDI), LusTRE web services have been integrated within existing metadata editors and geoportals. 相似文献
78.
ABSTRACTThe administration of U.S. President Donald Trump has promised to stop the ongoing spiralling down of the U.S. coal industry. We discuss the origins of the decline and assess the effects of policy interventions by the Trump administration. We find that, with fierce competition from natural gas and renewables, a further decrease of coal consumption must be expected by the old and inefficient U.S. coal-fired electricity generation fleet. By contrast, we consider the overly optimistic (for coal producers) view of the U.S. Energy Information Agency, and test whether the tide for the U.S. coal industry could turn as a result of three potential support measures: (i) revoking the Clean Power Plan (CPP); (ii) facilitating access to the booming Asian market; and (iii) enhanced support for Carbon Capture, Transport and Storage (CCTS) technology. We investigate the short-term and long-term effects on U.S. coal production using a comprehensive partial equilibrium model of the world steam coal market, COALMOD-World (Holz, Haftendorn, Mendelevitch, & von Hirschhausen, 2016). We find that revoking the CPP could stop the downward trend of steam coal consumption in the U.S., but even allowing for additional exports, will not lead to a return of U.S. coal production to the levels of the 2000s, that is, over 900?Mt per year. When global steam coal use is aligned with the 2°C climate target, U.S. steam coal production drops to around 100?Mt per year by 2030 and below 50?Mt by 2050, even if CCTS is available and exports via the U.S. West Coast is possible.Key policy insights
Declining U.S. coal use is primarily caused by competition from natural gas and renewables not by environmental regulation of the coal sector.
Without substantial policy support, U.S. coal-fired generation capacity will continue to decline rapidly.
Revoking the Clean Power Plan will lead to about one eighth higher U.S. coal production in the next years.
Carbon Capture, Transport and Storage does not prevent the rapid decline of coal use required under stringent climate policy.
Even in the most extreme pro-coal scenarios with additional export possibilities, U.S. coal production will not return to its pre-2010 levels.
79.
Climate Dynamics - Recent work has identified potential multi-year predictability in soil moisture (Chikamoto et al. in Clim Dyn 45(7–8):2213–2235, 2015). Whether this long-term... 相似文献
80.
Roman Tomaschitz 《Astrophysics and Space Science》2011,331(2):397-408
The effect of a cosmic time variation of Newton’s constant on galactic angular diameters, linear size, apparent magnitude,
and surface brightness is investigated. The redshift scaling of the gravitational constant is proportional to the Hubble parameter,
derived from the constancy of a moderate dimensionless ratio of fundamental constants, and manifested in galactic linear-size
evolution. The latter is demonstrated by fitting the angular size–redshift relation to spectroscopically and photometrically
selected samples of high-redshift rotators. The intrinsic luminosity evolution of the rotators and their magnitude–redshift
and surface brightness–redshift relations are studied. The galactic luminosity scales with a power of the Hubble parameter,
and the scaling exponent is inferred from a moderate dimensionless ratio involving the gravitational constant, the Galactic
luminosity, and the velocity of the Galaxy in the microwave background. The fits are performed with a cosmic expansion factor
derived from paleoplanetary surface temperatures. This expansion factor is tested by comparing the corresponding redshift
evolution of the angular-size distance to the distance estimates of two samples of galaxy clusters. 相似文献