Translucent Tin Dioxide Ceramics Obtained by Natural Sintering

Dense SnO₂-based ceramics (relative density >95%) have been obtained by natural sintering at a moderate temperature (≤ 1300°C) with the help of a small amount of manganese. Further thermal treatments above 1500°C result in grain growth and transport of manganese toward the sample surface. If the ceramic is embedded inside alumina powder, the diffusion of Mn out of the sample and into alumina during such heat treatments leads to a manganese-free body (<40 ppm) which is translucent. The transmission in the visible region depends on sample thickness; 61% was achieved for a 0.05 mm thick sample.     

A comparison between buffalo (Bubalus bubalis) and cow (Bos taurus) rumen fluids in terms of the in vitro fermentation characteristics of three fibrous feedstuffs

Rumen fluids from fistulated buffalos (Italy‐BRF) and cows (Netherlands‐CRF) were used as inocula to determine the fermentation kinetics of three forages. These were corn silage (CS), grass silage (GS) and wheat straw (WS) which had originated from both regions, giving six substrates in total. Fermentation kinetics was assessed by the measurement of cumulative gas production. Organic matter (OM) loss and volatile fatty acid (VFA) concentration at the end of the fermentation period were also determined. Both BRF and CRF ranked the substrates in the same order for total VFA, total gas production and the maximum rate of substrate degradation (CS > GS > WS). However, while the ranking of substrates was the same for both species, the absolute values differed significantly between the two inocula. Gas production, expressed as cumulative volume per unit mass of incubated (OMCV, ml g^?1) and as cumulative volume per unit mass of OM degraded (OM ml g^?1) for CRF was consistently higher than that for BRF for all substrates (p < 0.0001). VFA production, particularly of acetic and butyric acids, was significantly (p < 0.0001) lower for BRF than for CRF, though the digestibility of OM was the same for both inocula. VFA production predicted by the use of stoichiometric equations was generally higher than the observed gas production. These equations also predicted that the calculated amount of OM utilised for microbial growth was higher for BRF than for CRF. This may explain why diets having the same energy content but less protein can be fed to buffalo since they seem to have a lower requirement for protein compared with cattle. This possibility will need to be investigated in vivo. Given the similar ranking of feedstuffs between the two sources of inocula, these results suggest that either inoculum would be suitable for use in the cumulative gas production test as a measure of feedstuff evaluation. However, given the differences in absolute values, it is recommended that inocula from the species which will receive the feedstuff should be used. Copyright © 2004 Society of Chemical Industry     

Relationship between gelation and morphology of rubber-modified epoxy resins

The addition of both a solid and a liquid rubber to an epoxy resin has been shown to strongly increase the toughness of the material. Moreover, it is well known that toughening depends on the morphology of the system, which, in turn, depends on the cure conditions. In the present work the morphologies of epoxy resins modified with mixtures of solid and liquid rubbers have been studied through transmission electron microscopy. An investigation of the influence of the elastomers and of the gel time on the morphology of the hardened material was carried out. Gel times were evaluated, through rheological measurements, at different cure temperatures.     

Testability of artificial neural networks: A behavioral approach

Testability analysis of neural architectures can be performed at a very high abstraction level on the computational paradigm. In this paper, we consider the case of feed-forward multi-layered neural networks. We introduce a behavioral error model which allows good mapping of the physical faults in widely different implementations. Conditions for error controllability, observability and global testability are analytically derived; their purpose is that of verifying whether it is possible to excite all modeled errors and to propagate the error's effects to the primary outputs (actual test vectors being then technological-dependent). Mapping of physical faults onto behavioral errors is performed for some representative, architectures.     

Hall mobility in doped Si:H,Cl films

The Hall mobility μ_H in phosphorus- and boron-doped Si:H, Cl films was measured in the temperature range 130–300 K.The conductivity is markedly influenced by the doping, and the activation energies of both the Hall mobility and the conductivity as functions of the temperature are much lower in doped samples than in undoped samples. The process tends to become unactivated at higher doping levels.     

Biofeedback and relaxation training with three kinds of headache: Treatment effects and their prediction.

After a 4-wk baseline period during which daily ratings of headache activity were made and all participants took several psychological tests, 91 18–68 yr old patients with chronic headache (tension, migraine, and combined tension and migraine) were given a 10-session relaxation-training regimen. Ss who did not show substantial reductions in headache activity from the relaxation therapy were given a 12-session regimen of biofeedback (thermal biofeedback for vascular headaches and frontal EMG biofeedback for tension headaches). Relaxation therapy alone led to significant improvement for all groups, with a trend for the tension headache group to respond the most favorably. Biofeedback therapy led to further significant reduction in headache activity for all who received it, with a trend for combined migraine and tension headache patients to respond the most favorably. Multiple regression analyses revealed that approximately 32% of the variance in end-of-treatment headache diary scores could be predicted after relaxation and that 44% of the variance after biofeedback could be predicted using standard psychological tests. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchies of aggregation operators

This article deals with hierarchies of operators. In particular, we will analyze the problem of amalgamating individual opinions into a single group opinion, based upon hierarchical intensity aggregation rules. Our main goal is to decide whether hierarchical amalgamations are supported from an ethical and rational point of view. We will consider two different hierarchical procedures: cover-based hierarchical aggregations and ordered hierarchical aggregations, focusing here our attention to ordered hierarchical aggregations of OWA operators. In particular, we will obtain that basic key properties propagate under both hierarchical amalgamation rules, in the sense that the procedure itself will verify such properties whenever they are assumed for every partial amalgamation defining such a hierarchical procedure. © 1994 John Wiley & Sons, Inc.     

Mn influence on the electrochemical behaviour of Li3V2(PO4)3 cathode material

The role played by the substitution of Mn on the electrochemical behaviour of Li₃V₂(PO₄)₃ has been investigated. Independently of the synthesis route, the Mn doping improves the electrochemical features with respect to the undoped samples. Different reasons can be taken into consideration to explain the electrochemical enhancement. In the sol–gel synthesis the capacity slightly enhances due to the Mn substitution on both the V sites, within the solubility limit x = 0.124 in Li₃V_2−xMn_x(PO₄)₃. In the solid state synthesis the significant capacity enhancement is preferentially due to the microstructural features of the crystallites and to the LiMnPO₄ phase formation.