Isotopic and fluid inclusion study of hydrothermal and metamorphic carbonates in the Larderello geothermal field and surrounding areas, Italy

Fluid inclusions have been studied on six calcite veins from the shallow part (480 to 1515 m below ground level) of the Larderello geothermal field and outcropping in peripheral zones of the geothermal area. Oxygen and carbon isotopic analyses have been carried out on these carbonate veins, as well as on the dolostone layers found inside the Paleozoic metamorphic units of the deep part of the field (from 1939 to 3177 m below ground level). Fluid inclusion observations suggest that boiling processes probably occurred during calcite precipitation in most of the veins. The fluids that formed or interacted with the calcite veins below the uppermost reservoir (made up of Mesozoic marine carbonates), and with the calcite hydrothermal veins of Sassa, were characterised by an apparent salinity from 1.3 to 5.3 wt.% NaCl eq. and a homogenisation temperature from 137 to 245°C. The fluid inclusions related to the calcite veins hosted above the uppermost reservoir show a wide range of apparent salinity (from 1.7 to 22.2 wt.% NaCl eq.) and homogenisation temperatures from 224 to 296°C. Apparent salinity/homogenisation temperature covariations of the latter veins are interpreted as being the result of a mixing process between a low-temperature, high-salinity fluid and a higher-temperature, moderate-salinity fluid. The oxygen isotopic compositions of the calcite veins (δ¹⁸O from 10.34 to 11.45‰) located below the Mesozoic carbonates and in the outcrops (δ¹⁸O from 9.42 to 17.07‰) indicate that the vapour in equilibrium with these veins was isotopically similar to the present-day discharge steam. The aqueous fluids in equilibrium with these veins could be meteoric water that interacted with the Mesozoic carbonates of the upper reservoir. The δ¹³C values of the CO₂ produced at Larderello and the constant concentration of this gas over time are, however, indicative of a deep source inside the reservoir that is probably related to the decarbonation reaction within the metamorphic units that form the present-day deep reservoir. Fluid inclusion salinities (up to 22.2 wt.% NaCl eq.) and isotopic results (δ¹⁸O from 13.43 to 21.99‰, δ¹³C between −1.26 and −0.18‰) on the calcite veins hosted above the uppermost reservoir suggest that the water circulating in these veins has strongly interacted with Mesozoic carbonates or Neogene sediments containing evaporite layers. The isotopic values (δ¹⁸O from 14.09 to 19.91‰, δ¹³C from −4.09 to 1.90‰) of dolomite samples present in the Paleozoic metamorphic rocks indicate a reaction with fluid of variable temperatures under different water/rock ratios. The isotopic composition of one sample reveals equilibrium with present-day discharge fluids. This fact aside, the remaining data indicate that the Paleozoic dolomitic layers do not seem to contribute significantly to the production of CO₂.     

Grafting reactions onto polyorganophosphazenes. V. Photostabilization of poly[bis(4-benzylphenoxy)-phosphazene] by light-induced grafting copolymerization of acrylate polymers containing pendant HALS moieties

The light-induced grafting reaction of acrylate monomers containing hindered piperidine groups (HALS) onto poly[bis(4-benzylphenoxy)phosphazene] is described as a function of several different experimental parameters, i.e., type of photoinitiator (benzophenone or benzoin ethyl ether), monomer concentration, solvent composition, light intensity, and swelling of the polyphosphazene films. The obtained phosphazene-g-HALS-containing acrylate-grafted copolymers, irradiated with light of wavelength longer than 300 nm under accelerated photooxidative conditions to test the photostabilizing ability of the grafted HALS groups, showed that the hindered piperidine groups grafted onto the polyphosphazene matrix are able to considerably depress the damage caused to the poly[bis(4-benzylphenoxy)phosphazene] films during light exposure. The efficiency of this process seems to be related to the amount of HALS residues grafted onto the phosphazene substrates. © 1996 John Wiley & Sons, Inc.     

Parallel comparison of run-length-encoded strings on a linear systolic array

The length of the longest common subsequence (LCS) between two strings of M and N characters can be computed by an O(M × N) dynamic programming algorithm, that can be executed in O(M + N) steps by a linear systolic array. It has been recently shown that the LCS between run-length-encoded (RLE) strings of m and n runs can be computed by an O(nM + Nm − nm) algorithm that could be executed in O(m + n) steps by a parallel hardware. However, the algorithm cannot be directly mapped on a linear systolic array because of its irregular structure.In this paper, we propose a modified algorithm that exhibits a more regular structure at the cost of a marginal reduction of the efficiency of RLE. We outline the algorithm and we discuss its mapping on a linear systolic array.     

Effects of behavioral, cognitive, and combined treatments for assertion as a function of differential deficits.

Investigated the interaction of demonstrated knowledge of assertive behavior with treatments for nonassertive behavior to help clarify the interaction of deficits with treatments. 88 female undergraduates were classified as low or high on knowledge of assertive behavior and randomly assigned to 1 of 4 treatment conditions: behavioral rehearsal, cognitive self-statement, combined behavioral rehearsal/cognitive self-statement, and a waiting-list control group. Multiple measures were administered over time (e.g., Conflict Resolution Inventory). Results support the effectiveness of each treatment and the stability of treatment effect over a long-term follow-up but failed to support a differential treatment approach to assertion based on demonstrated knowledge. Behavioral and cognitive treatments seemed to have the greatest effect on measures that were similar to the treatment focus, but also registered effects on measures similar to the other treatment. Treatment groups had significantly higher self-efficacy scores than the controls, and self-efficacy correlated significantly with many dependent variables. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acoustic emission events from sodium vapour bubble collapsing: A stochastic model

The forward Kolmogorov equation method has been applied to a zero-dimensional model which describes the time distribution of acoustic emissions from sodium vapour bubble collapsing.Processes taken into account as components for outlining the upstated phenomenon are: energy generation, energy dissipation, bubble creation, acoustic emission and energy release from bubble collapsing.Processes involve affect or are induced by a population of particles (bubbles, acoustic pulses) and pseudoparticles (energetic units).A formulation is obtained for the expected values of some stochastic indicators, i.e. factorial moments and cumulants, autocorrelation function, waiting time distribution between contiguous events, of the time series consisting of acoustic emission pulses as detected by a suitable sensor.Preliminary but promising validation of the model and a sound prelude to an effective boiling regime diagnosing is obtained by processing data from the out-of-pile CFNa loop in Grenoble, France. Data are collected from a piezoelectric accelerometer located nearby the circuit.     

Photoinduced emission and thermoluminescence in topaz

Topaz has been demonstrated to be useful for dosimetric application. This mineral exhibits a satisfactory thermoluminescent (TL) response to radiation. In previous studies we analyzed the natural topaz samples from Minas Gerais, Brazil, by TL, infrared and X-ray diffraction techniques, with the aim of obtaining an explanatory model for the process of light emission of this mineral. Thermal treatments and irradiations do not produce significant changes in the TL emission. TL spectra exhibit a broad band with a maximum TL intensity at 420 nm in all the samples. In order to better understand the physical processes involved in the light emission of the topaz, we analyzed the photoinduced fluorescence of natural (as received) and thermally treated samples in powder form. The photoinduced emission of topaz was found to be similar to that of other silicates. In the UV–visible range there are intense emission bands between 350 and 550 nm, with a maximum intensity at 435 nm. The intensities are different for each sample.     

Selecting Focal Species in Ecological Network Planning following an Expert-Based Approach: A Case Study and a Conceptual Framework

In connectivity conservation and ecological network planning, the selection of focal fragmentation-sensitive species represents an a priori step. Despite their strategic role, selection of focal species has often been carried out following non-objective approaches. If this is done, actions of planning and conservation, especially in relation to biodiversity conservation, could be ineffective. We propose an expert-based approach to select focal species on the basis of sensitivity to three components of habitat fragmentation (habitat area reduction, increase of habitat isolation, increase of edge effect and landscape matrix disturbance) and of intrinsic ecological traits of the species (trophic level, dispersal ability, body size, niche breadth, rarity). A case study on terrestrial mammals of an area in Central Italy (province of Rome) shows that the species selected through this approach largely coincide with the species recognized in the literature as being fragmentation-sensitive. In this paper we present a conceptual framework to select focal species and to define a schematic methodology for ecological network planning and monitoring.     

Performance‐driven dynamic service selection

Modern software systems are increasingly built by integrating different services implemented by independent organizations and offered in an open service marketplace. In such environment, multiple providers may compete with each other by publishing services that provide the same functionality, and export the same interface, but differ in the offered QoS and in particular in the offered performance. Clients and service integrators may therefore dynamically select the most efficient services that satisfy their requirements among the competing alternatives. Service selection may be performed by clients by following different strategies, which may ultimately affect the overall quality of service invocations. In this paper, we address the problem of analyzing and comparing different service selection strategies based on a framework that supports performance estimates. We report on quantitative analyses through simulations, highlighting advantages and limitations of each strategy. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of tannin on increasing UF adhesive performance at high temperature investigated by TMA and TGA analysis

Tannins have been largely studied as wood additives and wood adhesives. In a perspective of a desirably increased utilization of natural raw material in the wood timber industries, this study provides further and specific information on the use of condensed tannins to improve the heat resistance of urea–formaldehyde (UF) resins. The results obtained by thermomechanical and thermogravimetric analyses show that high percentage (33 and 50 %) of quebracho tannin in UF-tannin blend dramatically improves the overall UF thermal resistance, but 50 % of tannin decreases the maximum value of modulus of elasticity (MOE) of the bonded joint. The best balance between mechanical performance and decreased degradation at high temperature is obtained with 33 % of quebracho tannin. The MOE value of UF + 33 % of quebracho tannin at 260 °C is seven times greater than MOE of UF control. Thermograms show that quebracho tannin has a beneficial effect on increasing the resistance of glue-mix to degradation induced by temperature. When the content of tannin in the glue-mix is increased up to 50 %, the resin degrades completely at about 670 °C, i.e. more than 50 °C higher than neat UF resin. This improvement is related mainly to the resorcinol-type ring structure of tannin and the alkaline pH of UF + quebracho tannin glue mix that confer a higher resistance against joint degradation to UF even at elevated temperatures.