Barium zinc borosilicate glasses with a molar composition xBaO-(60-x)ZnO-30B 2O 3-10SiO 2, where x ranged from 0 to 60 mol%, were prepared using melt-quenching method. The effect of BaO substitution for ZnO on the sintering, crystallization, and dielectric characteristics has been investigated. The behavior of the studied barium zinc borosilicate glasses was mainly determined by the relative amount of the structural modifier oxides (BaO and ZnO) and the ionic size, and field strength of the modifying cations (Ba 2+, Zn 2+). Increased amounts of BaO decreased both glass transition temperature and crystallization temperature, while increasing the relative dielectric constant. Sintering occurred before crystallization for glasses where substitution of BaO for ZnO was up to 30 mol%, but for higher substitution levels, crystallization occurred during the sintering process hindering densification. © 2012 The American Ceramic Society.

Borosilicate glass-alumina composites with (1 - x) Glass + x Al 2O 3 (x = 0, 5, 10, 25 vol.%) were prepared and the effect of Al 2O 3 addition on the structural, electrical and thermal characteristics was investigated. XRD patterns revealed the presence of cristobalite (SiO 2) in sintered borosilicate glass and that the addition of Al 2O 3 hinders cristobalite formation. This behavior is due to the diffusion of some Al 3+ ions from alumina to glass, which leads to changes in glass structure and composition as identified by SEM/EDS. Cristobalite was undetected in composites containing 10% Al 2O 3 that attained the lowest thermal expansion coefficient value (∼4.6 × 10 -6 °C -1). Conductivity (dc and ac) increased with the amount of Al 3+ ions present in the glass structure as modifiers and formers. Dielectric constant values, in the range 5.0-7.2, increased with Al 2O 3 addition and the values of loss tan δ (1.5-2.1 × 10 -2) indicate that these materials are good insulators. © 2012 Elsevier B.V. All rights reserved.

Samples of doped and undoped a-Si: H were deposited at temperatures ranging from 100 degrees C to 350 degrees C and then submitted to different dehydrogenation temperatures (from 350 degrees C to 550 degrees C) and times (from 1 h to 4 h). a-Si: H films were characterised after deposition through the measurements of specific material parameters such as: the optical gap, the conductivity at 25 degrees C, the thermal activation energy of conductivity and its hydrogen content. Hydrogen content was measured after each thermal treatment. Substrate dopant contamination from phosphorus-doped a-Si thin films was evaluated by SIMS after complete dehydrogenation and a junction depth of 0.1 mu m was obtained. Dehydrogenation results show a strong dependence of the hydrogen content of the as-deposited film on the deposition temperature. Nevertheless, the dehydrogenation temperature seems to determine the final H content in a way almost independent from the initial content in the sample. H richer films dehydrogenate faster than films with lower hydrogen concentration. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Samples of doped and undoped a-Si: H were deposited at temperatures ranging from 100 degrees C to 350 degrees C and then submitted to different dehydrogenation temperatures (from 350 degrees C to 550 degrees C) and times (from 1 h to 4 h). a-Si: H films were characterised after deposition through the measurements of specific material parameters such as: the optical gap, the conductivity at 25 degrees C, the thermal activation energy of conductivity and its hydrogen content. Hydrogen content was measured after each thermal treatment. Substrate dopant contamination from phosphorus-doped a-Si thin films was evaluated by SIMS after complete dehydrogenation and a junction depth of 0.1 mu m was obtained. Dehydrogenation results show a strong dependence of the hydrogen content of the as-deposited film on the deposition temperature. Nevertheless, the dehydrogenation temperature seems to determine the final H content in a way almost independent from the initial content in the sample. H richer films dehydrogenate faster than films with lower hydrogen concentration. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Building energy management may simultaneously integrate multiple energy areas and sources of information. The coordination of synergies allow better-informed decisions, such as performing forecasts and adjustments of energy production and storage, while adapting electrical loads to off-peak times, when energy rates are lower. This work targets the improvement and optimization of energy management operations in buildings and large complexes, by introducing a conceptual model for supporting real-time advanced reasoning and inference towards efficient energy management.

Suppose \(\alpha\) is an orientation-preserving diffeomorphism (shift) of \(\mathbb{R}_+=(0,\infty)\) onto itself with the only fixed points \(0\) and \(\infty\). In [KKL11] we found sufficient conditions for the Fredholmness of the singular integral operator with shift \[(aI-bW_\alpha)P_++(cI-dW_\alpha)P_-\] acting on \(L^p(\mathbb{R}_+)\) with \( 1 < p < \infty\), where \(P_\pm=(I\pm S)/2\), \(S\) is the Cauchy singular integral operator, and \(W_\alpha f=f\circ\alpha\) is the shift operator, under the assumptions that the coefficients \(a,b,c,d\) and the derivative \(\alpha'\) of the shift are bounded and continuous on \(\mathbb{R}_+\) and may admit discontinuities of slowly oscillating type at \(0\) and \(\infty\). Now we prove that those conditions are also necessary.

Suppose \(\alpha\) is an orientation preserving diffeomorphism (shift) of \(\mathbb{R}_+=(0,\infty)\) onto itself with the only fixed points \(0\) and \(\infty\). We establish sufficient conditions for the Fredholmness of the singular integral operator with shift \[ (aI-bW_\alpha)P_++(cI-dW_\alpha)P_- \] acting on \(L^p(\mathbb{R}_+)\) with \( 1 < p < \infty \), where \(P_\pm=(I\pm S)/2\), \(S\) is the Cauchy singular integral operator, and \(W_\alpha f=f\circ\alpha\) is the shift operator, under the assumptions that the coefficients \(a,b,c,d\) and the derivative \(\alpha'\) of the shift are bounded and continuous on \(\mathbb{R}_+\) and may admit discontinuities of slowly oscillating type at \(0\) and \(\infty\).

Toxic amides, such as acrylamide, are potentially harmful to Human health, so there is great interest in the fabrication of compact and economical devices to measure their concentration in food products and effluents. The CHEmically Modified Field Effect Transistor (CHEMFET) based on amorphous silicon technology is a candidate for this type of application due to its low fabrication cost. In this article we have used a semi-empirical model of the device to predict its performance in a solution of interfering ions. The actual semiconductor unit of the sensor was fabricated by the PECVD technique in the top gate configuration. The CHEMFET simulation was performed based on the experimental current voltage curves of the semiconductor unit and on an empirical model of the polymeric membrane. Results presented here are useful for selection and design of CHEMFET membranes and provide an idea of the limitations of the amorphous CHEMFET device. In addition to the economical advantage, the small size of this prototype means it is appropriate for in situ operation and integration in a sensor array.

Concurrent programs may suffer from concurrency anomalies that may lead to erroneous and unpredictable program behaviors. To ensure program correctness, these anomalies must be diagnosed and corrected. This paper addresses the detection of both low- and high-level anomalies in the Transactional Memory setting. We propose a static analysis procedure and a framework to address Transactional Memory anomalies. We start by dealing with the classic case of low-level dataraces, identifying concurrent accesses to shared memory cells that are not protected within the scope of a memory transaction. Then, we address the case of high-level dataraces, bringing the programmer's attention to pairs of memory transactions that were misspecified and should have been combined into a single transaction. Our framework was applied to a set of programs, collected form different sources, containing well known low- and high-level anomalies. The framework demonstrated to be accurate, confirming the effectiveness of using static analysis techniques to precisely identify concurrency anomalies in Transactional Memory programs.

High temperature superconducting (HTS) machines are recognized to offer several advantageous features when comparing to conventional ones. Amongst these, highlights the decrease in weight and volume of the machines, due to increased current density in conductors or the absence of iron slots' teeth; or the decrease in AC losses and consequent higher efficiency of the machines, even accounting for cryogenics. These concepts have been already demonstrated and some machines have even achieved commercial stage. In this paper, several alternative approaches are applied to electrical motors employing HTS materials. The first one is an all superconducting linear motor, where copper conductors and permanent magnets are replaced by Bi-2223 windings and trapped flux magnets, taking advantage of stable levitation due to flux pinning, higher current densities and higher excitation field. The second is an induction disk motor with Bi-2223 armature, where iron, ironless and hybrid approaches are compared. Finally, an innovative command strategy, consisting of an electronically variable pole pairs' number approach, is applied to a superconducting hysteresis disk motor. All these concepts are being investigated and simulation and experimental results are presented.