Methodology of X-ray fluorescence analysis of suspended matter in estuarine waters

Twenty-seven samples of suspended sediments collected on Millipore filters from the St. Lawrence estuary were directly analysed for Si, Al, Ca, Mg, Na, K, Fe, Ti, Mn, Ni, Co, Cu, Cr and Zn by X-ray fluorescence using standards prepared from suspended matter collected by continuous flow centrifugation. Calibration curves prepared from the analysis of these standards could be directly used in calculating the weight percent of elements for the unknown samples, if the weight of the total suspended matter on the filters did not exceed 25 mg.     

Source and distribution of trace metals and nutrients in Narmada and Tapti river basins,India

The study was designed to establish the distributions of trace metals, dissolved organic carbon, and inorganic nutrients as well as to assess the extent of anthropogenic inputs into the Narmada and Tapti rivers. Water and sediment qualities are variable in the rivers, and there are major pollution problems at certain locations, mainly associated with urban and industrial centers. The metal concentrations of samples of the aquatic compartments investigated were close to the maximum permissible concentration for the survival of aquatic life, except for higher values of Cu (5–763 μg l⁻¹), Pb (24–376 μg l⁻¹), Zn (24–730 μg l⁻¹), and Cr (70–740 μg l⁻¹) and for drinking water except for elevated concentrations of metals such as Pb, Fe (850–2,060 μg l⁻¹), Cr, and Ni (20–120 μg l⁻¹). In general, the concentrations of trace metals in the rivers vary down stream which may affect the “health” of the aquatic ecosystem and may also affect the health of the rural community that depends on the untreated river water directly for domestic use. The assessment of EF, I _geo, and PLI in the sediments reveals overall moderate pollution in the river basins.     

Primordial magnetic fields and formation of molecular hydrogen

We study the implications of primordial magnetic fields for the thermal and ionization history of the post-recombination era. In particular, we compute the effects of dissipation of primordial magnetic fields owing to ambipolar diffusion and decaying turbulence in the intergalactic medium (IGM) and the collapsing haloes, and compute the effects of the altered thermal and ionization history on the formation of molecular hydrogen. We show that, for magnetic field strengths in the range  2 × 10⁻¹⁰≲ B ₀≲ 2 × 10⁻⁹ G  , the molecular hydrogen fraction in IGM and collapsing halo can increase by a factor of 5 to 1000 over the case with no magnetic fields. We discuss the implication of the increased molecular hydrogen fraction on the radiative transfer of ultraviolet photons and the formation of first structures in the universe.     

Enhancement of Biogas Generation by Addition of Lipase in the Co‐Digestion of Tannery Solid Wastes

Co‐digestion studies were carried out for biogas generation using fleshings as the primary substrate and a mixture of primary and secondary sludge generated during the treatment of tannery wastewater as the co‐substrate. Steapsin, a commercial grade lipase, was added to enhance the hydrolysis in anaerobic co‐digestion. The lipase dosages used were ranging between 0.25 and 1.0 g for a volatile solids input of 7.5 g. The performance of the co‐digestion was assessed from the volume of biogas generated. Experimental results revealed an optimum lipase dosage of about 0.75 g. At this dosage, the biogas generation was observed to increase by about 15% compared to that in the control without adding lipase. Further, the digestion with lipase addition was observed faster since the digestion period was reduced about 30%. This means that the capacity of the digester could also be reduced about 30% leading to savings in its installation cost.     

The American Crocodile in Biscayne Bay,Florida

Intensive crocodile monitoring programs conducted during the late 1970s and early 1980s in southern Florida resulted in an optimistic outlook for recovery of the protected species population. However, some areas with suitable crocodile habitat were not investigated, such as Biscayne Bay and the mainland shorelines of Barnes and Card Sounds. The objective of our study was to determine status and habitat use of crocodiles in the aforementioned areas. Spotlight and nesting surveys were conducted from September 1996 to December 2005. The results revealed annual increases in the number of crocodiles. Crocodiles preferred protected habitats such as canals and ponds. Fewer crocodiles were observed in higher salinity water. The distribution and abundance of crocodilians in estuaries is directly dependent on timing, amount, and location of freshwater delivery, providing an opportunity to integrate habitat enhancement with ongoing ecosystem restoration and management activities.     

Interaction Between Two CMEs During 14 – 15 February 2011 and Their Unusual Radio Signature

We report a detailed analysis of an interaction between two coronal mass ejections (CMEs) that were observed on 14?–?15 February 2011 and the corresponding radio enhancement, which was similar to the “CME cannibalism” reported by Gopalswamy et al. (Astrophys. J. 548, L91, 2001). A primary CME, with a mean field-of-view velocity of 669 km?s^?1 in the Solar and Heliospheric Observatory (SOHO)/Large Angle Spectrometric Coronagraph (LASCO), was more than as twice as fast as the slow CME preceding it (326 km?s^?1), which indicates that the two CMEs interacted. A radio-enhancement signature (in the frequency range 1 MHz?–?400 kHz) due to the CME interaction was analyzed and interpreted using the CME data from LASCO and from the Solar Terrestrial Relations Observatory (STEREO) HI-1, radio data from Wind/Radio and Plasma Wave Experiment (WAVES), and employing known electron-density models and kinematic modeling. The following results are obtained: i) The CME interaction occurred around 05:00?–?10:00 UT in a height range 20?–?25 R_⊙. An unusual radio signature is observed during the time of interaction in the Wind/WAVES dynamic radio spectrum. ii) The enhancement duration shows that the interaction segment might be wider than 5 R_⊙. iii) The shock height estimated using density models for the radio enhancement region is 10?–?30 R_⊙. iv) Using kinematic modeling and assuming a completely inelastic collision, the decrease of kinetic energy based on speeds from LASCO data is determined to be 0.77×10²³ J, and 3.67×10²³ J if speeds from STEREO data are considered. vi) The acceleration, momentum, and force are found to be a=?168 m?s^?2, I=6.1×10¹⁸ kg?m?s^?1, and F=1.7×10¹⁵ N, respectively, using STEREO data.     

An Evaluation of Possible Mechanisms for Anomalous Resistivity in the Solar Corona

A wide variety of transient events in the solar corona seem to require explanations that invoke fast reconnection. Theoretical models explaining fast reconnection often rely on enhanced resistivity. We start with data derived from observed reconnection rates in solar flares and seek to reconcile them with the chaos-induced resistivity model of Numata and Yoshida (Phys. Rev. Lett. 88, 045003, 2002) and with resistivity arising out of the kinetic Alfvén wave (KAW) instability. We find that the resistivities arising from either of these mechanisms, when localized over length scales of the order of an ion skin depth, are capable of explaining the observationally mandated Lundquist numbers.     

Post-flare pulsations in the 54–78 MHz frequency band

Solar Physics - Quasi-periodic pulsations with periods mostly around 13&;nbsp;s in the frequency range of 54–78&;nbsp;MHz have been observed following the first X2&;nbsp;flare...