Dual-Temperature Acceleration Radiation

Astronomy Reports - We solve for a system that emits acceleration radiation at two different temperatures. The equilibrium states occur asymptotically in Planck distributions and transition...     

An integrated water balance model for assessing water scarcity in a data-sparse interfluve in eastern India

Abstract

The objective of this study is to measure the balance of water demand versus water resource availability in an interfluve of West Bengal, India to support water resource planning, particularly of inter-basin transfers. Surface water availability was modelled using the US Soil Conservation Service curve number (SCS-CN) approach, whilst groundwater availability was modelled based on water-level fluctuations and the rainfall infiltration method. Water use was modelled separately for the agricultural, industrial, and domestic sectors using a predominantly normative approach and water use to availability ratios calculated for different administrative areas within the interfluve. Overall, the approach suggested that the interfluve receives 327 × 10⁶ m³ year^-1 of excess water after satisfying these sectoral demands, but that the eastern part of the study area is in deficit. However, a sensitivity analysis carried on the approach to several assumptions in the model suggested changed circumstances would produce surplus/deficit ranging from ?215 × 10⁶ to 435 × 10⁶ m³ year^-1 . The approach could have potential for localised water balance modelling in other Indian catchments.

Editor D. Koutsoyiannis; Associate editor D. Hughes     

An alternative interpretation for the map expression of “abrupt” changes in lateral stratigraphic level near transverse zones in fold-thrust belts

The map expression of "abrupt" changes in lateral stratigraphic level of a thrust fault has been traditionally interpreted to be a result of the presence of(1) a lateral(or oblique) thrust-ramp,or(2) a frontal ramp with displacement gradient、and/or(3) a combination of these geometries.These geometries have been used to interpret the structures near transverse /ones in fold-thrust belts(FTB).This contribution outlines an alternative explanation that can result in the same map pattern by lateral variations in stratigraphy along the strike of a low angle thrust fault.We describe the natural example of the Leamington transverse zone.which marks the southern margin of the Pennsy lvanian—Permian Oquirrh basin with genetically related lateral stratigraphic variations in the North American Sevier(TB.Thus.the observed map pattern at this zone is closely related to lateral stratigraphic variations along the strike of a horizontal fault.Even though the present-day erosional level shows the map pattern that could be interpreted as a lateral ramp.the observed structures along the Leamington zone most likely share the effects of the presence of a lateral(or oblique) ramp,lateral stratigraphic variations along the fault trace.and the displacement gradient.     

Evaluating the impacts of watershed management on runoff storage and peak flow in Gav-Darreh watershed,Kurdistan, Iran

Recently, water and soil resource competition and environmental degradation due to inadequate management practices have been increased and pose difficult problems for resource managers. Numerous watershed practices currently being implemented for runoff storage and flood control purposes have improved hydrologic conditions in watersheds and enhanced the establishment of riparian vegetation. The assessment of proposed management options increases management efficiency. The purpose of this study is to assess the impact of watershed managements on runoff storage and peak flow, and determine the land use and cover dynamics that it has induced in Gav-Darreh watershed, Kurdistan, Iran. The watershed area is 6.27 km² which has been subjected to non-structural and structural measures. The implemented management practices and its impact on land use and cover were assessed by integrating field observation and geographic information systems (GIS). The data were used to derive the volume of retained water and determine reduction in peak flow. The hydrology of the watershed was modeled using the Hydrologic Engineering Center–Hydrologic Modeling System (HEC–HMS) model, and watershed changes were quantified through field work. Actual storms were used to calibrate and validate HEC–HMS rainfall–runoff model. The calibrated HEC–HMS model was used to simulate pre- and post-management conditions in the watershed. The results derived from field observation and HEC–HMS model showed that the practices had significant impacts on the runoff storage and peak flow reduction.     

Active Region Formation through the Negative Effective Magnetic Pressure Instability

The negative effective magnetic-pressure instability operates on scales encompassing many turbulent eddies, which correspond to convection cells in the Sun. This instability is discussed here in connection with the formation of active regions near the surface layers of the Sun. This instability is related to the negative contribution of turbulence to the mean magnetic pressure that causes the formation of large-scale magnetic structures. For an isothermal layer, direct numerical simulations and mean-field simulations of this phenomenon are shown to agree in many details, for example the onset of the instability occurs at the same depth. This depth increases with increasing field strength, such that the growth rate of this instability is independent of the field strength, provided the magnetic structures are fully contained within the domain. A linear stability analysis is shown to support this finding. The instability also leads to a redistribution of turbulent intensity and gas pressure that could provide direct observational signatures.     

Book reviews

Mechanics of Sediment Transport. Edited by B. Mutlu Sumer and A. Muller. Proceedings of Euromech 156, Istanbul, 12–14 July 1982. Rotterdam: A. A. Balkema, 1983. 285 pp. $45.00.

Gear Drive Systems: Design and Application, Peter Lynwander, New York and Basel: Marcel Dekker, Inc., 1983. Price: $49.50.     

The matter in the Big-Bang model is dust and not any arbitrary perfect fluid!

We consider a spherically symmetric general relativistic perfect fluid in its comoving frame. It is found that, by integrating the local energy momentum conservation equation, a general form of g ₀₀ can be obtained. During this study, we get a cue that an adiabatically evolving uniform density isolated sphere having ρ(r,t)=ρ ₀(t), should comprise “dust” having p ₀(t)=0; as recently suggested by Durgapal and Fuloria (J. Mod. Phys. 1:143, 2010) In fact, we offer here an independent proof to this effect. But much more importantly, we find that for the homogeneous and isotropic Friedmann-Robertson-Walker (FRW) metric having p(r,t)=p ₀(t) and ρ(r,t)=ρ ₀(t), \(g_{00} = e^{-2p_{0}/(p_{0} +\rho_{0})}\). But in general relativity (GR), one can choose an arbitrary t→t _?=f(t) without any loss of generality, and thus set g ₀₀(t _?)=1. And since pressure is a scalar, this implies that p ₀(t _?)=p ₀(t)=0 in the Big-Bang model based on the FRW metric. This result gets confirmed by the fact the homogeneous dust metric having p(r,t)=p ₀(t)=0 and ρ(r,t)=ρ ₀(t) and the FRW metric are exactly identical. In other words, both the cases correspond to the same Einstein tensor \(G^{a}_{b}\) because they intrinsically have the same energy momentum tensor \(T^{a}_{b}=\operatorname {diag}[\rho_{0}(t), 0,0, 0]\).