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In this paper we address the problem of uncertainty in the design and planning of a multi-period, multi-product closed loop supply chain, where the recovered products are end-of-life products that are disassembled and recycled. Uncertainty is explicitly modelled by considering customers’ demands and returns to be stochastic. A two–stage model is developed where first stage decisions concern the facility location while second stage decisions are the production planning of the supply chain. The integer L- shaped method was adopted as the solution tool and computational tests were performed on multi-period and multi-commodity networks randomly generated based on a reference case. A comparison between the proposed solution method and the straight use of the CPLEX is performed.

The present study is part of an extensive research project, where the main objective is to evaluate a strengthening solution for reinforced concrete structures using a small thickness jacketing in the compression side of the RC element with unidirectional fiber reinforced grout - UFRG.
For this purpose a high performance cementitious grout reinforced with continuous and unidirectional non woven fibermat has been developed. It was expected that the use of these type of fibers allowed an optimization of its percentage and orientation. It was expected that the use of these type of fibers allowed an optimization of its percentage and orientation. Besides, for continuous fibers (with an aspect ratio, defined as the length-to-diameter ratio, l/d=∞), the composite should attain higher tensile strength since the fiber embedment length is enough to prevent fiber pullout.
The experimental campaign included a set of preliminary tests that allowed the design of the fiber reinforced grout, sustained with rheological parameters [7] and mechanical characterization tests of the materials.
Finally, an experimental campaign was carried out in order to proceed to the mechanical characterization of the unidirectional fiber reinforced grout. Compressive tests were conducted in small thickness tubular specimens that enable the determination of the compressive strength and the static modulus of elasticity of the material. The tensile strength of the material was obtained using splitting tests of cubic specimens (according the standard DIN 1048-5). The experimental results are presented and analyzed.

In this work the design and planning of a Closed-Loop Supply Chain (CLSC) under uncertain conditions is considered and a two-stage scenario-based modeling approach is proposed in order to deal with this multi-product, multi-period problem. The network design and tactical plan are simultaneously optimized in a given time horizon, comprehending the raw material acquisition and the processing, storage and distribution of intermediates, returns and final products. Uncertainty is associated to the returns, both in terms of their quantity, which is customer dependent, and quality, which is determined at the sorting centers. Therefore, the ensuing mathematical MILP formulation considers the simultaneous integration of two important uncertainty sources, which represents an important modeling advantage, allowing a better understanding of the reverse network structure. For each probabilistic scenario, the model estimates the amount of products to be returned by customers and of returns to be remanufactured for each quality level, as well as the storage levels. Several tests based on a real sized example of a Portuguese glass company are undertaken in order to show the applicability of the developed approach. Based on these tests, the influence of the uncertain quality and quantity of returns on the design and planning of the CLSC is assessed.

Mass balances of ash and potassium for a fluidized bed combustor were performed incorporating measurement uncertainties. The total output mass of ash or a chemical element should be equal to the mass in the input fuel; however, this is not often achieved. A realistic estimation of recovery uncertainty can support the reliability of a mass balance. Estimation of uncertainty helps to establish a reliable evaluation of the recovery ratio of ash mass and elemental mass. This may clarify whether any apparent lack in closing the mass balance can be attributed to uncertainties. The evaluation of measurement uncertainty for different matrices, namely coal, biomass, sand and ashes from different streams was based on internal quality control data and external quality control data, namely analysis of samples from proficiency tests or use of a certified reference material. The evaluation of intermediate precision and trueness allowed the estimation of measurement uncertainty. Due to the different physic and chemical characteristics of the studied matrices, the uncertainty of precision was evaluated using R-charts of data obtained from the analysis of duplicates for the majority of samples. This allowed evaluating sample heterogeneity effects. The instrumental acceptance criterion was also considered and included in the combined uncertainty. The trueness was evaluated using data from several proficiency tests and from analysis of a certified reference material or sample spiking. Statistically significant bias was included.

The properties of the light flexible device, ion jelly, which combines gelatin with an ionic liquid (IL) were recently reported being promising to develop safe and highly conductive electrolytes. This article aims for the understanding of the ion jelly conductive mechanism using dielectric relaxation spectroscopy (DRS) in the frequency range 10−1−106 Hz; the study was complemented with differential scanning calorimetry (DSC) and pulse field gradient nuclear magnetic resonance (PFG NMR) spectroscopy. The room temperature ionic liquid 1-butyl-3-methylimmidazolium dicyanamide (BMIMDCA) used as received (1.9% w/w water content) and with 6.6% (w/w) of water content and two ion jellies with two different ratios BMIMDCA/gelatin/water % (w/w), IJ1 (41.1/46.7/12.2) and IJ3 (67.8/25.6/6.6), have been characterized. A glass transition was detected by DSC for all materials allowing for classifying them as glass formers. For the ionic liquid, it was observed that the glass transition temperature decreases with the increase of water content. While in subsequent calorimetric runs crystallization was observed for BMIMDCA with negligible water content, no crystallization was detected for any of the ion jelly materials upon themal cycling. To the dielectric spectra of all tested materials, both dipolar relaxation and conductivity contribute; at the lowest frequencies, electrode and interfacial polarization highly dominate. Conductivity, which manifests much more intensity relative to dipolar reorientations, strongly evidences subdiffusive ion dynamics at high frequencies. From dielectric measures, transport properties as mobility and diffusion coefficients were extracted. Data treatment was carried out in order to deconvolute the average diffusion coefficients estimated from dielectric data in its individual contributions of cations (D+) and anions (D−). The D+ values thus obtained for IJ3, the ion jelly with the highest IL/gelatin ratio, cover a large temperature range up to room temperature and revealed excellent agreement with direct measurements from PFG NMR, obeying to the same VFT equation. For BMIMDCA6.6%water, which has the same water amount as IJ3, the diffusion coefficients were only estimated from DRS measurements over a limited temperature range; however, a single VFT equation describes both DRS and PFG NMR data. Moreover, it was found that the diffusion coefficients and mobility are similar for the ionic liquid and IJ3, which points to a role of both water and gelatin weakening the contact ion pair, facilitating the translational motion of ions and promoting its dissociation; nevertheless, it is conceivable that a critical composition of gelatin that leads to those properties. The VFT temperature dependence observed for the conductivity was found to be determined by a similar dependence of the mobility. Both conductivity and segmental motion revealed to be correlated as inferred by the relatively low values of the decoupling indexes. The obtained results show that ion jelly could be in fact a very promising material to design novel electrolytes for different electrochemical devices, having a performance close to the IL but presenting an additional stability regarding electrical measurements and resistance against crystallization relative to the bulk ionic liquid.

Three species of biomass origin (straw pellets, olive cake and wood pellets) and two coals from different countries (Coal Polish and Coal Colombian) have been studied to understand the fate of their ash forming matter during the combustion process and to investigate the influence of co-firing biomass with coal. Three different approaches to investigate the ash behaviour were employed: (1) chemical fractionation analysis to evaluate the association/reactivity of ash forming elements in the fuels as a prediction tool, (2) establishment of elements partitioning in ash streams produced in the combustion and co-combustion trials, and (3) evaluation of enrichment factors of elements in the ash streams. The chemical fractionation analysis was applied to all fuels used to evaluate how the association/reactivity of elements making up ash may influence their behaviour during combustion. Combustion tests were carried out on a pilot scale fluidized bed combustor (FBC). Four ash streams were obtained at different locations. The uncertainty of measurements was estimated allowing a critical evaluation of mass balances over the combustion system and the partitioning of elements in the ash streams. The enrichment factors of elements in the several ash streams were estimated, incorporating uncertainties associated with analytical measurements. Results obtained showed that for FBC the relation between the chemical fractionation and the experimental partitioning is strongly affected by elutriation of particles. The element enrichment factor estimated for each ash stream, using Al as a reference element, revealed better correlations with the elements reactivity obtained by chemical fractionation because it overcomes particles elutriation effects. Nevertheless, it was observed that the reactivity estimated by chemical fractionation could not be solely interpreted as tendency of the elements to volatilize on FBC system, as reaction in bed zone of boiler may also occur retaining reactive elements.

The main aim of this work was to assess the possibility of using biomass ashes as substitutes for cement and natural aggregates in concretes without compromising their mechanical and chemical properties. Thirteen concrete formulations were prepared with different percentages of bottom and fly ashes produced at a forest biomass power plant. These formulations were submitted to mechanical compressive strength assays, after 28, 60 and 90 days of maturation. The reference formulation F1 that was produced without biomass ashes and one formulation incorporating fly and bottom ashes, F4, were selected for further characterization. After 90 days of maturation, the selected formulations were submitted to the leaching test described in the European Standard EN12457-2 (L/S ratio of 10 L/kg, in a batch extraction cycle of 24h) by using two different leaching agents: a synthetic marine medium (ASPM medium) and a synthetic freshwater medium (ISO 6341 medium). The eluates produced were submitted to chemical characterization which comprised a set of metals (As, Sb, Se, Cu, Zn, Ba, Hg, Cd, Mo, Pb, Ni, Cr, Cr VI, Al, Fe, Mg, Na, K and Ca), pH, SO42-, F-, dissolved organic carbon, chlorides, phenolic compounds and total dissolved solids. The substitution of 10% cement by fly ashes has not promoted the reduction of the compressive strength of concrete. The new formulation F4 has presented emission levels of chemical species similar or even lower to those observed for the reference formulation F1.

A set of methods defining an API (Application Programming Interface) are to be made thread safe; thus running any subset of these methods in parallel should not create races or deadlocks. Originally, the set of methods were not designed to be thread safe, so races and deadlocks are expected when running them in parallel. The number of possible interleavings when running methods from this API in parallel is huge, and this work focuses on the identification of the high level data races introduced by such interleavings. We propose an analysis that avoids the exhaustive exploration of all possible interleavings. For a concurrent program P, the closure of P, clos(P), is defined. Roughly speaking, we can say that the clos(P) is obtained by adding threads to P in such a way that high level data races resulting from running P in parallel to other programs are exposed statically. A set of methods representing the API is then modeled as a set of concurrent programs and their closure is analysed to identify high level data races. These high level data races are then inspected and removed to make the API thread safe. We illustrate the application of this methodology with a simple use case.

In this paper, the solution of the asymmetric eigenvalue complementarity problem (EiCP) is investigated by means of a variational inequality formulation. This problem is then solved by finding a stationary point of the gap function and the regularized gap function. A nonlinear programming formulation of the EiCP results from the gap function. A hybrid algorithm combining a projection technique and a modified Josephy-Newton method is proposed to solve the EiCP by finding a stationary point of the regularized gap function. Numerical results show that the proposed method can in general solve EiCPs efficiently.

{Zinc alkyl cations supported by N,N-BIAN-type bidentate ligands were found to be highly active in the immortal ROP of epsilon-caprolactone to yield narrowly disperse and chain length-controlled poly(epsilon-caprolactone), whether in solution or bulk polymerization conditions.}

{{A series of Ar-BIAN-based copper(I) complexes (where Ar-BIAN = bis(aryl) acenaphthenequinonediimine) were synthesised and characterised by H-1 and C-13 NMR spectroscopies, FT-IR spectroscopy, MALDI-TOF-MS spectrometry, cyclic voltammetry and single crystal X-ray diffraction. The bis-chelated complexes of general formula {[}Cu(Ar-BIAN)(2)]BF4 (where Ar = C6H5 (1), 4-iPrC(6)H(4) (3), 2-iPrC(6)H(4) (4)) were prepared by reaction of {[}Cu(NCMe)(4)]BF4 with two equivalents of the corresponding Ar-BIAN ligands, in dichloromethane, while the mono-chelated complexes of the type {[}Cu(Ar-BIAN)L2]BF4 (where Ar = 2,6-iPr(2)C(6)H(3)

The 3D scanning electro-optical characteristics of a data acquisition prototype system integrating a 32 linear array of 1D amorphous silicon position sensitive detectors (PSD) were analyzed. The system was mounted on a platform for imaging 3D objects using the triangulation principle with a sheet-of-light laser. New obtained results reveal a minimum possible gap or simulated defect detection of approximately 350 μm. Furthermore, a first study of the angle for 3D scanning was also performed, allowing for a broad range of angles to be used in the process. The relationship between the scanning angle of the incident light onto the object and the image displacement distance on the sensor was determined for the first time in this system setup. Rendering of 3D object profiles was performed at a significantly higher number of frames than in the past and was possible for an incident light angle range of 15 ° to 85 °. © 2012 Optical Society of America.

Supply chain management must adopt different and more innovative strategies that support a better response to customer needs in an uncertain environment. Supply chains must be more agile and be more capable of coping with disturbances, meaning that supply chains must be more resilient. The simultaneous deployment of agile and resilient approaches will enhance supply chain performance and competitiveness. Accordingly, the main objective of this paper is to propose a conceptual framework for the analysis of relationships between agile and resilient approaches, supply chain competitiveness and performance. Operational and economic performance measures are proposed to facilitate the monitoring of the influence of these practices on supply chain performance. The influence of the proposed agile and resilient practices on supply chain competitiveness is also examined in terms of time to market, product quality and customer service.