The efficient design and operation of supply chains with return flows represent a major optimization challenge, given the high number of factors involved and their intricate interactions. In particular, the quality level of the return products has strong economic and societal implications and depends greatly on the type of product (glass, paper, electronic, oil, etc) and on the degree of consumers’ readiness, frequently promoted by various kinds of awareness raising campaigns. A multi-product multi-period model was previously developed by the authors [1] for the closed-loop supply chain (CLSC) design and planning, where strategic and tactical decisions were comprehensively considered. This model is now being extended to handle the uncertainty related to the quality of the returned products, which at this stage is modeled by a two-stage scenario-based stochastic approach. General strategies to solve optimization problems involving uncertainty tend to exhibit poor computational performance, due to the problem NP-hard complexity, which tends to worsen with the problem size. Therefore and, in addition, a model performance solution enhancement is also being explored. To increase the efficiency of the solution approach, an alternative representation to some of the integer variables employed in the mathematical formulation was developed, which is tested by means of computational experiments being performed on illustrative real sized examples.

In 1968, Gohberg and Krupnik found a Fredholm criterion for singular integral operators of the form \(aP+bQ\), where \(a,b\) are piecewise continuous functions and \(P,Q\) are complementary projections associated to the Cauchy singular integral operator, acting on Lebesgue spaces over Lyapunov curves. We extend this result to the case of Nakano spaces (also known as variable Lebesgue spaces) with certain weights having finite sets of discontinuities on arbitrary Carleson curves.

Indium doped, and undoped, zinc oxide films were deposited using aerosol assisted chemical vapour deposition (AACVD) at atmospheric pressure on glass substrates. Electrical measurements (I-V) showed a reduction in resistivity following the addition of indium, and XRD analysis revealed an associated switch to c-axis preferred crystal orientation. The ability of the films to oxidise organic material on their surface was analysed using stearic acid as the model contaminant under ultra-violet (UV, 365 nm) irradiation. The In-doped films displayed a greater rate of organic decomposition, which we attribute to the formation of a platelet surface structure having a larger surface area than the undoped films, on which the UV generated electrons and holes may react to form active photocatalytic species. In addition we suggest that the switch to c-axis crystal orientation may reduce the electron-hole pair recombination rate at the grain boundaries, due to an improvement in crystallinity and related reduction in carrier scattering losses, leading to an increase in photocatalytic organic decomposition rate. © 2011 Elsevier B.V. All rights reserved.

The final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample polarization. By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between then. Two peaks have been identified for polyamide 11, one associated with the glass transition around 60 degrees C and the second associated with the Curie transition around 96 degrees C.

The final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample polarization. By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between then. Two peaks have been identified for polyamide 11, one associated with the glass transition around 60 °C and the second associated with the Curie transition around 96 °C.

The final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample polarization. By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between then. Two peaks have been identified for polyamide 11, one associated with the glass transition around 60 degrees C and the second associated with the Curie transition around 96 degrees C.

In this paper, we report the environmental, optical, and gate bias stress stability of amorphous zinc-tin-oxide (ZTO) thin-film transistors (TFTs) fabricated by sol-gel spin-coating method. The ZTO TFTs showed excellent environmental and optical stability. The threshold voltage stability of ZTO TFTs was sensitive to both positive and negative gate bias stress. Maximum threshold voltage shifting of +1.9 and -3.2 V was observed under a gate bias stress of +10 and -10 V, respectively, with no significant change to subthreshold swing value. © 2006 IEEE.

An equivalent model and electromechanical characteristics for the disk motor was obtained based on the Steinmetz parameters. This paper describes a series of tests conducted on an axial flux motor, equipped with an aluminum rotor disc and an YBCO high temperature superconducting rotor disc, at liquid nitrogen temperature (77 K). The rotating magnetic field was produced by a four-pole, three-phase stator winding, at 50 Hz. At asynchronous permanent regime, Steinmetz-type models are able to describe both motors' behavior. From the performed tests, the parameters of both motors' models were deduced. A variable load was used to obtain both motor's characteristics (conventional and superconducting). Experimental obtained characteristics of both motors are compared with the ones predicted from parameters' calculation. The HTS motor provides high efficiency then the conventional ones.

The energy resource management is a major concern worldwide. Energy management activities minimize environmental impacts of the energy production. Therefore, electric energy consumption monitoring has been proposed as an important process which makes immediate reductions in energy use and CO(2) emissions. In recent years, advances in electronics have allowed the implementation of many technological solutions that could help to reduce energy consumption. This paper describes the design and prototyping of a home electric energy monitoring system that provides residential consumers with real time information about their electricity use. The system uses wireless communication and displays the information on a small LCD screen and on a computer.

Respiratory nitric oxide reductase (NOR) was purified from membrane extract of Pseudomonas (Ps.) nautica cells to homogeneity as judged by polyacrylamide gel electrophoresis. The purified protein is a heterodimer with subunits of molecular masses of 54 and 18 kDa. The gene encoding both subunits was cloned and sequenced. The amino acid sequence shows strong homology with enzymes of the cNOR class. Iron/heme determinations show that one heme c is present in the small subunit (NORC) and that approximately two heme b and one non-heme iron are associated with the large subunit (NORB), in agreement with the available data for enzymes of the cNOR class. Mossbauer characterization of the as-purified, ascorbate-reduced, and dithionite-reduced enzyme confirms the presence of three heme groups (the catalytic heme b(3) and the electron transfer heme b and heme c) and one redox-active non-heme Fe (Fe-B). Consistent with results obtained for other cNORs, heme c and heme b in Ps. nautica cNOR were found to be low-spin while FeB was found to be high-spin. Unexpectedly, as opposed to the presumed high-spin state for heme b(3), the Mossbauer data demonstrate unambiguously that heme b(3) is, in fact, low-spin in both ferric and ferrous states, suggesting that heme b(3) is six-coordinated regardless of its oxidation state. EPR spectroscopic measurements of the as-purified enzyme show resonances at the g similar to 6 and g similar to 2-3 regions very similar to those reported previously for other cNORs. The signals at g = 3.60, 2.99, 2.26, and 1.43 are attributed to the two charge-transfer low-spin ferric heme c and heme b. Previously, resonances at the g similar to 6 region were assigned to a small quantity of uncoupled high-spin Fe-III heme b(3). This assignment is now questionable because heme b(3) is low-spin. On the basis of our spectroscopic data, we argue that the g = 6.34 signal is likely arising from a spin spin coupled binuclear center comprising the low-spin Fe-III heme b(3) and the high-spin Fe-B(III). Activity assays performed under various reducing conditions indicate that heme b(3) has to be reduced for the enzyme to be active. But, from an energetic point of view, the formation of a ferrous heme-NO as an initial reaction intermediate for NO reduction is disfavored because heme [FeNO](7) is a stable product. We suspect that the presence of a sixth ligand in the Fe-II-heme b(3) may weaken its affinity for NO and thus promotes, in the first catalytic step, binding of NO at the Fe-B(II) site. The function of heme b(3) would then be to orient the Fe-B-bound NO molecules for the formation of the N-N bond and to provide reducing equivalents for NO reduction.

The European Union directive for electric and electronic waste, published in 2003, enforced all European countries to meet some targets concerning the recycling and recovery of these products. This directive was transposed to the Portuguese legislation in 2004. Following this, a group of EEE producers set up an organization (Amb3e) whose mission was to design and manage a nationwide recovery network for WEEE, which will be the subject matter of this work. A generic MILP model is proposed to represent this network, which is applied to its design and planning, where the best locations for collection and sorting centres are chosen simultaneously with the definition of a tactical network planning. Several analyses are performed to provide further insights regarding the selection of these alternative locations. The results gave support to the company strategic expansion plans for a high number of centres to be opened and to their location near the major WEEE sources.