Hyperonic equation of state     

William D. Langer  Leonard C. Rosen 《Astrophysics and Space Science》1970,6(2):217-227

An equation of state for cold matter at neutron star densities, >10¹⁴ gm/cm³, is evaluated. The gas is considered to be a degenerate mixture of neutrons, protons, leptons, hyperons and massive baryons. We derive the equilibrium equations including the effects of nuclear interactions among all the hadrons.  相似文献   

Nucleosynthesis in neutron star atmospheres     

Leonard C. Rosen 《Astrophysics and Space Science》1969,5(2):150-170

The composition of neutron star atmospheres is calculated as a function of time including effects of diffusion, cooling and thermonuclear reactions. A seven-component nuclear reaction network with includes He⁴, C¹², O¹⁶, Ne²⁰, Mg²⁴, Si²⁸ and Fe⁵⁶ is utilized. Neutron star models with different initial nuclear abundances are compared as to subsequent nucleosynthesis. It is found that the final abundances are independent of original composition assuming He⁴ as the major initial constituent. The final composition of the atmosphere is predominantly Fe⁵⁶. Mass loss from an evolving neutron star is examined as a possible source of cosmic rays. It is found that a neutron star contributes only Fe⁵⁶ significantly to the cosmic-ray spectrum.  相似文献   

Particle diffusion in degenerate,ionized gases     

Leonard C. Rosen 《Astrophysics and Space Science》1969,5(1):92-102

A perturbation treatment is used to find the distribution functions from the Boltzmann transport equation for a two-component ionized, degenerate gas. General expressions are found for the diffusion coefficient and relative diffusion velocity. Tables are given for specific values of spin and mass ratio.  相似文献   

Inferring the location of catchment characteristic soil moisture monitoring sites. Covariance structures in the temporal domain     

Tomas K. Thierfelder  Rodger B. Grayson  Dietrich von Rosen  Andrew W. Western 《Journal of Hydrology》2003,280(1-4):13-32

Information shortage is a fundamental constraint in catchment hydrology that severely affects the possibilities for secure inference of the generic hydrologic landscape, as well as for secure validation of physically deduced distributed models. The introduction of databases with high enough spatiotemporal resolution to properly reflect generic hydrological catchment characteristics may therefore be considered as an inferential breakthrough. The work presented here is part of a project where observations from such an Australian catchment (the Tarrawarra) are utilised to estimate the discrepancy for individual soil moisture monitoring sites in reflecting generic catchment characteristics. With low enough discrepancy, observation sites may be considered as catchment characteristic soil moisture monitoring (CASMM) sites, thus capturing unbiased catchment characteristics and being well suited to represent the catchment in a monitoring effort. In this particular study, covariance structures in the temporal domain are inferred in order to enable subsequent enquiries regarding CASMM discrepancies. This is accomplished with ARMAX filters applied to the conditional auto- and cross-covariance structures that connect observations of soil moisture to the temporal variation of meteorology. The results suggest that weekly observations of Tarrawarra soil moisture are quite consistent realisations of first order auto-regressive processes, which means that the present state of soil moisture is generally acquired through the past week. With auto-correlative effects filtered out, cross-correlative meteorological effects on Tarrawarra soil moisture are identified and generally represented by the present week's accumulation of rainfall, the present week's accumulation of global radiation, and the previous week's maximum wind speed. After successive filtering of conditional cross-correlative effects, residual time-series observations may be considered as temporally independent, and therefore are well suited for subsequent inferences regarding covariance structures in the spatial domain. Since the exclusion of auto-correlative effects is necessary for unambiguous model interpretation, the estimated cross-correlative parameters should reflect the true nature of underlying physical processes.  相似文献   

An Outline of a Guidance Framework for Assessing Hydrogeological Risks at Early Stages   总被引：1，自引：0，他引：1  

Lars Rosen  Harry E. LeGrand 《Ground water》1997,35(2):195-204

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An algorithm for on-the-fly K shortest paths finding in multi-storey buildings using a hierarchical topology model     

Rosen Ivanov 《International journal of geographical information science》2018,32(12):2362-2385

This article presents an approach to computing K shortest paths in large buildings with complex horizontal and vertical connectivity. The building topology is obtained from Building Information Model (BIM) and implemented using directed multigraphs. Hierarchical design allows the calculation of feasible paths without the need to load into memory the topology of the entire building. It is possible to expand the graph with new connectivity on-the-fly. The paths calculated may be composed of traversable building components that are located inside the buildings or those that are both inside and outside buildings. The performance (computational time and heap size used) is optimized by using the appropriate collections (maps, lists and sets). The proposed algorithm is evaluated in several use-case scenarios – complete graphs and real building environments. In all test scenarios, the proposed path finding algorithm is faster and uses less memory when compared to the fast version of the Yen’s KSP algorithm. The proposed approach can be successfully used as a first level of coarse-to-fine path finding algorithms.  相似文献   

Toronto’s condo-builders: development approaches and spatial preferences     

Gillad Rosen 《Urban geography》2017,38(4):606-625

The City of Toronto has undergone a number of dramatic transformations in the last several decades morphing from an industrial-driven metropolis into a thriving real estate and consumer amenities market. Over these decades, the development of condominiums has significantly transformed Toronto’s cityscape surpassing by far other types of real estate development. Based chiefly on a series of interviews with property developers and local politicians, this article explores development from the perspective of condo developers. The article identifies the key condo developers and categorizes them according to their development approaches and spatial preferences. Findings reiterate the need to consider property developers as highly diverse and flexible place entrepreneurs. Differences play out not merely in preferred development location and size, but also in target population, tenure mix, corporate structure, and the extent to which capitalism and economic gain are mixed with more idealistic motivations such as social benefits.  相似文献   

Controls on the chemical composition of groundwater from alluvial aquifers in the Wanaka and Wakatipu basins, Central Otago, New Zealand     

Michael Rosen  Sarah Jones 《Hydrogeology Journal》1998,6(2):264-281

 Groundwater in alluvial aquifers of the Wakatipu and Wanaka basins, Central Otago, New Zealand, has a composition expressed in equivalent units of Ca²⁺≫Mg²⁺≅Na⁺>K⁺ for cations, and HCO₃ ^–≫SO₄ ^2->NO₃ ^–≅Cl^– for anions. Ca²⁺ and HCO₃ ^– occur on a 1 : 1 equivalent basis and account for >80% of the ions in solution. However, some groundwater has increased proportions of Na⁺ and SO₄ ^2-, reflecting a different source for this water. The rock material of the alluvial aquifers of both basins is derived from the erosion and weathering of metamorphic Otago Schist (grey and green schists). Calcite is an accessory mineral in both the grey and green schists at <5% of the rock. Geological mapping of both basins indicates that dissolution of calcite from the schist is the only likely mechanism for producing groundwater with such a constant composition dominated by Ca²⁺ and HCO₃ ^– on a 1 : 1 equivalent basis. Groundwater with higher proportions of Na⁺ and SO₄ ^2- occurs near areas where the schist crops out at the surface, and this groundwater represents deeper and possibly older water derived from basement fluids. Anomalously high K⁺ in the Wakatipu basin and high NO₃ ^– concentrations in the Wanaka basin cannot be accounted for by interaction with basement lithologies, and these concentrations probably represent the influence of anthropogenic sources on groundwater composition. Received, June 1996 Revised, March 1997, July 1997 Accepted, July 1997  相似文献   

Comparison of Downhole and Surface Sampling for the Determination of Volatile Organic Compounds (VOCs) in Ground Water     

Michael E. Rosen  James F. Pankow  Jacob Gibs  Thomas E. Imbrigiotta 《Ground Water Monitoring & Remediation》1992,12(1):126-133

The relative precision and accuracy of sampling and analysis methods for the determination of trace concentrations of volatile organic compounds (VOCs) in ground water were compared. Samples were collected from a well containing nanogram-per-liter (ng/L) to microgram-per-liter (μg/L) levels of VOCs. A Keck helical rotor submersible pump was used to collect samples at the surface for analysis by purge and trap (P&T) and for analysis by adsorption/thermal desorption (ATD). Downhole samples were collected by passing water through an ATD cartridge. Although slight spontaneous bubble outgassing occurred when the water was brought to the surface, the relative precisions and comparabilities of the surface and downhole methods were generally found to be equivalent from a statistical point of view. A main conclusion of this study is that bringing sample water to the surface for placement in VOC vials (and subsequent analysis by P&T) can be done reliably under many circumstances. However, care must still be taken to prevent adsorption losses and cross contamination. Samples subject to strong bubble outgassing will need to be handled in a special fashion (e.g., by downhole ATD) to minimize volatilization losses. Additionally, the higher sensitivity of the ATD method allows lower detection limits than are possible with P&T. For example, several compounds present at the ng/L level could be determined with confidence by ATD, but not by P&T.  相似文献   

Carbon tetrachloride lifetimes and emissions determined from daily global measurements during 1978–1985     

P. G. Simmonds  D. M. Cunnold  F. N. Alyea  C. A. Cardelino  A. J. Crawford  R. G. Prinn  P. J. Fraser  R. A. Rasmussen  R. D. Rosen 《Journal of Atmospheric Chemistry》1988,7(1):35-58

Seven years of daily gas chromatographic measurements of CCl₄ at the five globally distributed ALE/GAGE surface sites are reported. It is determined that CCl₄ has been accumulating in the atmosphere at a rate of 1.3±0.1%/yr over the period 1978–1985 and that the releases of CCl₄ into the atmosphere have remained fairly constant, with the smallest releases in 1981–1982. Using an inversion scheme based on a nine box model of the atmosphere, we infer a CCl₄ lifetime of approximately 40 yr, an inventory on 1 July 1978 of (2.08±0.07)×10⁹ kg and an average rate of release over the period 1978–1985 of (0.9±0.9)×10⁷ kg/yr. These results produce excellent agreement with a release scenario derived from global production estimates for CCl₄ and the major CCl₄ byproduct, the chlorofluorocarbons. However, to obtain this consistency, it is necessary that our current ALE/GAGE absolute calibration standard be reduced approximately 25% thus bringing it into agreement with measurements by Yokohata et al. (1985) and Hanst et al. (1975).  相似文献