Using nocturnal water level fluctuations for estimating seepage from stormwater detention systems

A simple method, modified from White's method, was developed and verified for estimating seepage from two stormwater detention areas (SDAs) for 2 years, using night‐time changes in surface water levels. The SDAs were located in warm sub‐tropical Florida where the assumption of negligible night‐time evaporation for White's method does not hold true. Daily seepage was estimated using the nocturnal water level fluctuations on no flow days during winter when evaporation losses were insignificant. Specific yield, rather than the composite specific yield, provided accurate seepage estimates. The average annual seepage from the two SDAs was 2.03 m/year. At almost 70% of surface flows, seepage is a significant contributor to regional surface and sub‐surface flows. Comparison of seepage estimates from the night‐time method (NM) and the water balance (WB) method showed that the NM‐based estimates were within the range of the estimates from the WB method. At SDA1, the differences between the NM and WB estimates were 1% and 11%, for the 2 years. The discrepancy between the two estimates became higher (27% and 23%) at SDA2. Larger differences at SDA2 were because of higher error in quantifying pumped inflows for the WB method. Successful performance of NM combined with its low resource (single well monitoring) requirements will help quantify seepage from detention areas and other similar features (e.g. ponds, constructed wetlands) in warmer climates. A scale‐up for the Caloosahatchee River basin showed that seepage from SDA's accounted for 15% of annual river flows indicating the importance of seepage in evaluating water and chemical balances. Copyright © 2015 John Wiley & Sons, Ltd.     

<Emphasis Type="Italic">Guembelitria</Emphasis> (foraminifera) in the upper cretaceous-lower paleocene succession of the Langpar Formation,India and its paleoenvironmental implication

Guembelitria is an essential biotic component in the Late Cretaceous-Early Paleogene (K/Pg) marine successions to provide crucial information about the K/Pg boundary; however, it is not well studied in Indian subcontinent. Biostratigraphically well constrained K/Pg successions of Therriaghat and Mahadeo in the East Khasi Hills District, Meghalaya, India provided a scope to present a comprehensive account of the genus in the perspective of differences of opinion about its species. A total of six species including Guembelitria langparensis n. sp., are recognized and their stratigraphic distribution is recorded. A review of the taxonomic validity of the known species, an evaluation of the diverse concepts of Guembelitria cretacea Cushman, and semiquantitative analysis of the recovered species permitted their clustering into two morphogroups that had different ecology. Morphogroup I comprising Guembelitria cretacea, Guembelitria trifolia and Guembelitria langparensis n. sp., is characterized by flared and short spire tests that form a bioseries and thrived as surface floaters. Morphogroup II comprising Guembelitria irregularis, Guembelitria danica and Guembelitria sp a, possesses high spire, narrow tests that have morphological abnormalities and had preference for living in subsurface stressed environment. The occurrence of the species and accompanying other features like ratio of planktonic to benthic foraminifera (p/b), lithologic assemblage and incidence of phosphorite, are used to infer depositional environments and sea level changes during successive biozones of the sequence. The recognized Guembelitria events during the K/Pg transition are discussed with reference to world occurrences.     

Analytical Expression for Vertical Stress within an Inclined Mine Stope with Non-parallel Walls

Arching is a phenomenon that occurs in many situations in geotechnical engineering. When underground mine stopes are backfilled, a significant fraction of the self-weight of the backfill is carried by the side walls. As a result, the vertical stress at the bottom of the stope is significantly less than its overburden pressure. Few analytical expressions published in the literature can be used to determine the vertical stresses of stope with parallel walls. The objective of this paper is to extend the analytical solution previously developed by the authors to long plane-strain stopes with non-parallel walls with both slopes leaning to the same side. Different combinations of wall inclination are examined using the new analytical expression developed. To validate the analysis, the proposed results are compared with numerical model results. The results show that the proposed analytical expression is capable of estimating the vertical stress within mine stopes when the inclination of the hangingwall to the horizontal (α) is less than that of footwall (β). An important behavioural trend for the stress distribution is observed, where with the same overburden pressure and base width, the stress magnitude experienced by fill material significantly varies depending on the wall inclination.     

Holographic dark energy with linearly varying deceleration parameter and escaping big rip singularity of the Bianchi type-V universe

The present work deals with the accretion of two minimally interacting fluids: dark matter and a hypothetical isotropic fluid as the holographic dark energy components onto black hole and wormhole in a spatially homogeneous and anisotropic Bianchi type-V universe. To obtain an exact solution of the Einstein’s field equations, we use the assumption of linearly varying deceleration parameter. Solution describes effectively the actual acceleration and indicates a big rip type future singularity of the universe. We have studied the evolution of the mass of black hole and the wormhole embedded in this anisotropic universe in order to reproduce a stable universe protected against future-time singularity. It is observed that the accretion of these dark components leads to a gradual decrease and increase of black hole and wormhole mass respectively. Finally, we have found that contrary to our previous case (Sarkar in Astrophys. Space. Sci. 341:651, 2014a), the big rip singularity of the universe with a divergent Hubble parameter of this dark energy model may be avoided by a big trip.     

H α Observations of 8 June, 2004 Venus Transit

The cosmic event of Venus transit across the solar disk occurred on 8 June, 2004. The previous such event was witnessed about 122 years ago on 6 December, 1882. We observed this rare transit in H _α 6563 Å line-center from Udaipur Solar Observatory (USO) using both the full-disk and small field-of-view solar telescopes. In the earlier historical transits, a “black-drop” effect was observed in white light images, during the contact phases. The transit of 8 June, 2004 provided a unique opportunity to observe this effect, for the first time, in H _α. We report that the “black-drop” effect is present in H _α also, as in the white light observations made by the ground-based Global Oscillation Network Group (GONG) instrument and the space-borne Transition Region and Coronal Explorer (TRACE) satellite. We did not observe any noticeable “aureole” (atmospheric glow) around Venus during the ingress or egress phases. We have compared the H _α images with the multi-wavelength data obtained from the TRACE satellite.     

Water Balance Study for a Basin Integrating Remote Sensing Data and GIS

Water balance of a basin involves estimation of input precipitation, runoff, infiltration and evapotranspiration (ET). Although ET may have large variations over a big basin, it is commonly estimated using a few point measurements and this makes the estimation error prone. Satellite based remote sensing data provides few parameters for estimation of energy fluxes, at the land surface and atmosphere interaction in a distributed manner using the meteorological parameters. These parameters through surface energy balance equation have been used for the estimation of ET in this study. Various spatially distributed variables required for ET estimation; viz. NDVI, surface albedo, surface temperature etc. have been derived using remote sensing and ancillary data for Tapi basin located in western India. Beside this field data such as rainfall, air temperature, relative humidity, sunshine hours etc. have been used. For computation of runoff, Soil Conservation Services (SCS) approach has been considered. Tapi basin up to Ukai dam has been selected as the study area. Satellite data from National Oceanic and Atmospheric Administration (NOAA), Polar Orbiting Environmental Satellite, which carries the Advanced Very High Resolution Radiometer (AVHRR), have been used for preparation of various maps required for runoff and ET analysis. The results of runoff and ET have been compared with observed data for 2 years, 2002–2003 and the results have been found in good agreement with observed data.     

Performance Enhancement of Solar Latent Heat Thermal Storage System with Particle Dispersion — an Exergy Approach

Phase change material (PCM) employed latent heat thermal storage (LHTS) system has been showing good potential over the years for energy management, particularly in solar energy systems. However, enhancement in thermal conductivity of PCMs is emphasized as PCMs are known for their poor thermal conductivity. In this work, the thermal performance of a shell and tube LHTS module containing PCM‐metal particles composite is investigated while charging and is compared with that of pure PCM system. The effect of particle dispersion on latent heat capacity of pure PCM is also analyzed. Enthalpy based governing equations are solved numerically adopting FLUENT code. Exergy based performance evaluation is taken as a main aspect. The numerical results are presented for various operating conditions of heat transfer fluid (HTF) and indicate considerable performance improvement of the system when particles are dispersed.     

Trace elements geochemistry and petrogenesis of basalt from the southern part of the East Pacific Rise

Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR, representing a super-fast spreading axis is discussed. Trace element data classify these basalts into Normal and Transitional types of MORB, however, LREE enrichment is also observed in few of them. Chondrite normalized REE data plots show highly fractionated nature of these lavas, suggesting their derivation from the primitive mantle source. Petrogenetic modeling of the data suggests variation in the solidus pressure (14–20 kb.) and temperature (1316–1425°C), where 15 to 20% partial melting of the mantle is accountable for the generation of the melt. The pressure and temperature conditions at the beginning of the mantle melting were high along higher latitudes (24°S of EPR), but it gradually lowered down in the lower latitudinal areas (6°S of EPR), supporting for the presence of passively rising upper mantle beneath the Southern EPR.