Conversion of waste to electricity in a microbial fuel cell using newly identified bacteria: <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis>

The present study deals with the capability of pulp industry wastewater to produce bioelectricity with isolation and screening of native electrogenic bacteria from wastewater. In the screening process, three bacterial isolates were obtained; they were studied on the basis of morphology and biochemical characteristics. The maximum bioelectricity producing bacteria was identified by sequencing method and was identified as Pseudomonas fluorescens, and it is a novel bacteria reported in bioelectricity production from pulp industry wastewater. Further, the work focuses on optimization of various parameters, i.e., inoculum size, pH, temperature, mediators and its concentration. It was observed that with pulp industry wastewater, inoculum size of 1.5% gave the maximum voltage and current of 1.244 ± 0.003^d V and 5.946 ± 0.005^d mA, respectively. A pH of 7.0 gave maximum voltage and current of 0.956 ± 0.009^e V and 2.692 ± 0.016^e mA. At 35 °C temperature, maximum production of voltage and current of 1.045 ± 0.003^d V and 2.167 ± 0.037^d mA were recorded. Among the various mediators, humic acid was found to be most effective as it produced a voltage of 1.054 ± 0.004^f V and current of 1.070 ± 0.004^d mA. Maximum voltage of 1.291 ± 0.021^f V and current of 1.896 ± 0.006^f mA were recorded with 200 μM of humic acid. Physicochemical analysis of the effluent was conducted before and after experimental run, and the values suggested that the microbial fuel cell technology is an efficient method for biological treatment of wastewater.     

High magnitude global seismicity and lateral velocity gradients

Summary A new significant correlation has been sought between high magnitude global seismicity and lateral surface wave velocity gradients. Rayleigh wave velocity divisioning of Eurasia, Africa, Pacific Ocean, Atlantic Ocean and Indian Ocean into regions of similar group velocity dispersion character of 30 sec period bySanto andSato [1]³) has been mainly used for calculating the gradients. It is quite striking to note that all earthquakes of magnitude 8.6 and above during 1897–1956 have occurred in regions having gradients of the order of 1.5·10^–3 sec^–1.Finally, some potential areas for high magnitude earthquake occurrences are predicted and the possible velocity gradients in regions, where division pattern is not yet investigated like South America and Australia, are also estimated.N.G.R.I. Contribution No. 70-170.     

Analysis of threshold and incipient conditions for sediment movement

Prediction of threshold conditions and incipient motion is the essential issue for the study of sediment transport. This work compares existing empirical threshold curves proposed for Shields diagram, a method based on the concept of probability of sediment movement, and an empirical method based on movability number. These methods are used to predict the incipient motion conditions for experimental runs taken from various studies. Most of the experimental data, used in this work, have not been used before in derivation of alternative formulations for Shields diagram and other methods. The empirical threshold curves based on the Shields entrainment function was the least successful at predicting the measured incipient motion conditions, while the use of the movability number gives good predictions of critical shear velocity compared with experimental data.     

Structural chemistry of synthetic cordierite: Evidence for solid solutions and disordered compositional domains in Bi-flux-grown Mg-cordierites

The structure, crystal chemistry, and microstructure of disordered and ordered Mg-cordierites synthesized in a bismuth oxide flux system have been studied by a combination of x-ray and neutron powder diffraction and quantitative x-ray microanalysis using analytical electron microscopy. Microchemical data obtained on Bi-flux cordierites using energy-dispersive x-ray analysis is interpreted through comparison with data collected on stoichiometric Mg₂Al₄Si₅O₁₈ glass and α- and β-cordierite samples synthesized by subsolidus crystallization of the glass. Bi-flux cordierites crystallize in both the hexagonal and orthorhombic polymorphs and contain 5 to 10 at% occupancy of bismuth on the C1 and C2 channel sites. The microstructure of Bi-flux α-cordierite is characterized by the existence of local domains of disordered cordierite solid solutions with variable composition and significant vacancy concentrations on the octahedral site. The β-cordierites have a more homogeneous microstructure but are still Al-deficient, Si-rich solid solutions.     

Geochemical Eccentricity of Ground Water Allied to Weathering of Basalts from the Deccan Volcanic Province,India: Insinuation on CO<Subscript>2</Subscript> Consumption

Analyses of 72 samples from Upper Panjhara basin in the northern part of Deccan Plateau, India, indicate that geochemical incongruity of groundwater is largely a function of mineral composition of the basaltic lithology. Higher proportion of alkaline earth elements to total cations and HCO₃>Cl + SO₄ reflect weathering of primary silicates as chief source of ions. Inputs of Cl, SO₄, and NO₃ are related to rainfall and localized anthropogenic factors. Groundwater from recharge area representing Ca + Mg–HCO₃ type progressively evolves to Ca + Na–HCO₃ and Na–Ca–HCO₃ class along flow direction replicates the role of cation exchange and precipitation processes. While the post-monsoon chemistry is controlled by silicate mineral dissolution + cation exchange reactions, pre-monsoon variability is attributable chiefly to precipitation reactions + anthropogenic factors. Positive correlations between Mg vs HCO₃ and Ca + Mg vs HCO₃ supports selective dissolution of olivine and pyroxene as dominant process in post-monsoon followed by dissolution of plagioclase feldspar and secondary carbonates. The pre-monsoon data however, points toward the dissolution of plagioclase and precipitation of CaCO₃ supported by improved correlation coefficients between Na + Ca vs HCO₃ and negative correlation of Ca vs HCO₃, respectively. It is proposed that the eccentricity in the composition of groundwater from the Panjhara basin is a function of selective dissolution of olivine > pyroxene followed by plagioclase feldspar. The data suggest siallitization (L < R and R _k) as dominant mechanism of chemical weathering of basalts, stimulating monosiallitic (kaolinite) and bisiallitic (montmorillonite) products. The chemical denudation rates for Panjhara basin worked out separately for the ground and surface water component range from 6.98 to 36.65 tons/km²/yr, respectively. The values of the CO₂ consumption rates range between 0.18 × 10⁶ mol//km²/yr (groundwater) and 0.9 × 10⁶ mol/km²/yr (surface water), which indicates that the groundwater forms a considerable fraction of CO₂ consumption, an inference, that is, not taken into contemplation in most of the studies.     

Magma-hydrothermal system interaction inferred from volcanic gas measurements obtained during 2003–2008 at Meakandake volcano,Hokkaido, Japan

Phreatic eruptions occurred at the Meakandake volcano in 1988, 1996, 1998, 2006, and 2008. We conducted geochemical surveillance that included measurements of temperature, SO₂ emission rates, and volcanic gas composition from 2003 to 2008 at the Nakamachineshiri (NM), Northwest (NW), and Akanuma (AK) fumarolic areas, and the 96–1 vent, where historical eruptions had occurred. The elemental compositions of the gases discharged from the different areas are similar compared with the large variations observed in volcanic gases discharged from subduction zones. All the gases showed high apparent equilibrium temperatures, suggesting that all these gases originated from a common magmatic gas. The gases discharged from each area also exhibited different characteristics, which are probably the results of differences in the conditions of meteoric water mixing, quenching of chemical reactions, and vapor-liquid separation. The highest apparent equilibrium temperatures (about 500°C) were observed in the case of NW fumarolic gases, despite the low outlet temperature of about 100°C at these fumaroles. Since the NW fumaroles were formed as a result of the 2006 phreatic eruption, the high-temperature gas supply to the NW fumarole suggests that the phreatic eruption was caused by the ascent of high-temperature magmatic gases. The temperatures, compositions, and emission rates of the NM and 96–1 gases did not show any appreciable change after the 2006 eruption, indicating that each fumarolic system had a separate magmatic-hydrothermal system. The temperatures, compositions, and emission rates of the NM fumarolic gases were apparently constant, and these fumaroles are inferred to be formed by the evaporation of a hydrothermal system with a constant temperature of about 300°C. The 96–1 gas compositions showed large changes during continuous temperature decrease from 390° to 190°C occurred from 2003 to 2008, but the sulfur gas emission rates were almost constant at about four tons/day. At the 96–1 vent, the SO₂/H₂S ratio decreased, while the H₂/H₂O ratio remained almost constant; this was probably caused by the rock-buffer controlled chemical reaction during the temperature decrease.     

A reanalysis of the relationship between strong westerlies and precipitation in the Great Plains and Midwest regions of North America

A conceptual model relating expanded or strengthened mid-latitude summer westerlies with summer precipitation patterns has been used to explain past drought events in the Great Plains and Midwest of North America, including drought between 1200 and 1400 AD. However, this relationship was originally described using 20 years of instrumental data from the mid 20{th} century, and has not been verified with modern datasets. We reinvestigated the relationship between July westerlies and precipitation in the United States using instrumental records of the last 55 years. We also investigated whether changes in summer zonal flow patterns associated with precipitation anomalies represent a shift in the latitude of peak westerly winds or an increase in wind speed, or a combination of both.Finally, we briefly compare the pattern of precipitation anomalies to paleoclimatic records of drought between 1200 and 1400 AD. Results confirm that strong westerlies are associated with a band of decreased precipitation extending from the northern Rockies into the Midwest. Changes in summer westerlies associated with these patterns are characterized by a strengthening of mean westerly winds, with only a slight southward shift of peak winds over the Atlantic. Changes in the strength of the westerlies over both the Pacific and Atlantic appear to be important to precipitation deficits in the Midwest. Proxy-climate records from 1200 to 1400 AD indicate widespread drought in the Great Plains and Midwest, consistent with the hypothesis of stronger westerlies at this time. However, drought conditions also extended to other regions of North America, indicating a more detailed understanding of the potential causes and synoptic climatology is needed.     

Suppressing non‐Gaussian noises with scaled receiver wavefield for reverse‐time migration: comparison of different approaches

Numerical implementation of the gradient of the cost function in a gradient‐based full‐ waveform inversion (FWI) is essentially a migration operator used in wave equation migration. In FWI, minimizing different data residual norms results in different weighting strategies of data residuals at receiver locations prior to back‐propagation into the medium. In this paper, we propose different scaling methods to the receiver wavefield and compare their performances. Using time‐domain reverse‐time migration (RTM), we show that compared to conventional algorithms, this type of scaling is able to significantly suppress non‐Gaussian noise, i.e., outliers. Our tests also show that scaling by its absolute norm produces better results than other approaches.