Natural gas consumption and climate: a comprehensive set of predictive state-level models for the United States

Separate models correlating natural gas (NG) consumption to climate have been developed for the residential and commercial sectors of the 50 U.S. states. The models relate a population-weighted average temperature to state per capita NG consumption on a monthly basis. The majority of the models have Pearson correlation coefficients greater than 0.90 supporting the use of temperature as the sole independent parameter. The sensitivities of the models to a 1°C increase in temperature, are compared for each state and the monthly sensitivity to climate integrated over the entire U.S. is investigated for a range of temperature perturbations. The predicted impact of a 1°C increase in mean monthly temperature on U.S. consumption is an 8.1% decrease in the residential sector and a 5.9% decrease in the commercial sector. In terms of the net consumption normalized over the study period (1984–1993) this corresponds to a 111.8 TWh decrease in the residential sector and a 47.0 TWh decrease in the commercial sector. The largest change for a single month occurs in January when consumption would decrease 19.7 TWh in the residential sector and 7.4 TWh in the commercial sector.     

Electrochemical mechanism and flotation of chalcopyrite and galena in the presence of sodium silicate and sodium sulfite

The electrochemical mechanism involved in the selective separation of chalcopyrite from galena was investigated by flotation and electrochemical methods in the presence of sodium sulfite and sodium silicate, respectively, as a single depressant and their mixture as a combined depressant. Flotation tests revealed that the floatability of chalcopyrite was unaffected by depressants and its recovery remained constant (>80%) within the studied dosage range. Galena flotation was severely depressed with descending depressing order as follows: combined depressant > sodium silicate > sodium sulfite. Electrochemical analysis confirmed the high affinity of depressants on the galena surface, resulting in the formation of hydrophilic species, such as lead sulfite, lead sulfate, and lead orthosilicate. The oxidation of chalcopyrite sutrface and depressants did not exhibit any signals; conversely, the self-oxidation of chalcopyrite was depressed. The results of cyclic voltammograms well agreed with flotation results, demonstrating that chalcopyrite primarily reacted with the collector O-isopropyl-N-ethyl thionocarbamate and that galena mostly reacted with depressants.     

Sublanguages and registers: a note on terminology

The term sublanguage from mathematical linguistics confuses interaction researchers and leads them to believe that implementing natural language interfaces is easier than it is. The term register from sociolinguistics is proposed instead.     

Potentiality of “orujillo” (olive oil solid waste) to produce hydrogen by means of pyrolysis

The extraction of olive oil generates great amounts of solid waste and wastewater. The objective of this work is to evaluate the potentiality of slow pyrolysis of the solid oil waste, known as “orujillo”, to produce hydrogen rich gases. The effect of temperature and of different treatments of pyrolysis vapors on the yield and composition of the gases has been experimentally studied. “Orujillo” was pyrolyzed at 500 °C and 700 °C, and the pyrolysis vapors produced were directly fed to a second reactor where they were treated at 800 °C in different ways: just thermally, thermally treated through a refractory alumina bed and thermo-catalytically treated through a three layer bed (alumina + SiC mixed with Ni catalyst + alumina). The catalyst used was a commercial prereduced nickel-catalyst which contains 44 wt% Ni over calcium aluminate support (CaO/Al₂O₃). Concerning the effect of temperature, it has been proved that the raise in temperature leads to a decrease in the liquid yields and an increase in the gas yields, as well as to an increase in H₂ and a decrease in CO₂ content of the gases. With respect to the vapors treatments it has been observed that as a general rule any of the treatments reduces liquid and increases gas yields, and concerning gas composition, H₂ content increases, CO slightly increases and CO₂ decreases. These effects are more pronounced when the Ni-catalyst is used. With the Ni-catalyst about 50 wt% gas yield is obtained, with ≈ 50 vol% H₂ both at 500 and at 700 °C.     

A nanoreactor based on SrTiO3 coupled TiO2 nanotubes confined Au nanoparticles for photocatalytic hydrogen evolution

A TiO₂ nanotube-based nanoreactor was designed and fabricated by facile two steps synthesis: firstly, hydrothermal synthesized SrTiO₃ was deposited on TiO₂ nanotubes (TiO₂NTs). Secondly, the Au nanoparticles (NPs) were encapsulated inside the TiO₂NTs followed by vacuum-assisted impregnation. The as-synthesized composites were characterized using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Photoluminescence spectra (PL) and Ultraviolet–visible absorption spectroscopy (UV–vis). The photocatalytic performance was evaluated by the hydrogen evolution reaction. The results revealed that the SrTiO₃ modified TiO₂NTs confined Au NPs (STO-TiO₂NTs@Au) achieved an enhanced hydrogen evolution rate at 7200 μmol h⁻¹ g⁻¹, which was 2.2 times higher than that of bald TiO₂NTs@Au at 3300 μmol h⁻¹ g⁻¹. The improved photocatalytic activity could be attributed to the synergistic effect of the electron-donating of SrTiO₃ and TiO₂NTs confinement. The as-designed nanoreactor structure provides an example of efficient carriers' separation photocatalyst.     

Stable Carbon and Oxygen Isotope Records From Lake Erie Sediment Cores: Mollusc Aragonite 4600 BP–200 BP

We present the first δ¹⁸O and δ¹³C data from mollusc aragonite from Lake Erie for the 4.6–0.2 ka (4600 BP to 200 BP ¹⁴C yrs) time interval and describe single and composite species isotope trends. Composite species δ¹⁸O data show an almost 2.0%o increase from 3.3 to 3.0 ka followed by a nearly 2.5%o decrease at 2.8 ka. Oxygen isotope values then fluctuate by < l‰ until 0.2 ka. This trend in oxygen values is also evident in single species analyses of Sphaerium striatinurn. The most dramatic changes in isotope values, which occur from 3.3–2.8 ka, may reflect a pattern of water level changes in Lake Erie which occurred during the Nipissing flood and its lower water aftermath. Carbon isotope data show progressively more ¹³C enriched values from 4.6 ka (averaging–6.5‰ PDB) to the present (–0.57‰). This trend may reflect the dilution of isotopically light CO₂ from the oxidation of organic matter due to rising lake levels. The short-term increase in δ¹⁸O values is coupled with a corresponding decrease in δ¹³C values. A similar pattern for Lake Erie prior to 10.5 ka was also associated with a lowering of water levels in the lake.     

Measurement of the fragmentation efficiency of rock mass blasting and its mining applications

A new approach in evaluating the fragmentation efficiency of rock mass blasting is presented. It differs from most of the methods as it is predicated on a pre-existing in situ block size distribution in the rock mass as defined by the natural discontinuity network. Blasting therefore accomplishes the supplementary fragmentation of the already fragmented rock mass, the efficiency of which depends on the blasting parameters employed. The blasting efficiency is evaluated through comparison of the block size distributions of the rock mass and the corresponding muck pile. The estimate of the former is achieved by discontinuity network modelling in three dimensions with the aim of identifying the in situ blocks formed and measuring their volumes. For the muck pile, image analysis techniques applied to “randomly-taken” photos are used to derive the resulting block size distribution. Validation of the proposed method on various mines is presented as well as its significant and practical mining applications.     

Rapid measurement of suspended C,N, and P from Precambrian Shield Lakes using Near-infrared Reflectance Spectroscopy

Rapid (<2 min), simultaneous, non-chemical, non-destructive, cost-efficient measurement of the C, N, and P concentrations in suspended, particulate matter in water from lakes of varying trophic status, pH, and extent of metal contamination was attempted by the use of near-infrared reflectance spectroscopy (NIRS). This technique, widely used in the agricultural, food, pharmaceutical, petrochemical, and textile industries, is being explored for its applications to aquatic and environmental sciences. Suspended matter from lake water (10–100 ml) was collected on 2.5 cm dia. G/FC glass fibre filters so that filters bore 10.5–109.2 μg C, 0.8–18.9 μg N, and 0.09-2.67 μg P per filter. Filters were oven-dried and scanned with an NIRSystems 6500 near-infrared spectrophotometer. The spectral data were treated by multiple linear regression analysis to develop mathematical relationships (calibrations) between absorbance at particular wavelengths and amounts of C, N, and P determined by conventional chemical analytical methods. These calibrations were used to predict C, N, and P from an independent set of spectra. Agreement between these NIRS-predicted values and their chemical values was generally greater than 0.9 for C, N, and P (r² from 0.88 to 0.97).