Integrated planning of acquisition,disassembly and bulk recycling: a case study on electronic scrap recovery

Abstract. Due to national and supranational legislation activities, the recovery of discarded products will attain an increasing momentum. Electronic equipment consists of many different parts and materials. Therefore, the related recovery process is often divided into disassembly to remove harmful substances or reusable parts and into bulk recycling to recover ferrous and non-ferrous metals. In order to consider the interactions between choice of scrap to be recovered (acquisition problem), disassembly and bulk recycling, a mixed-integer linear programming model for integrated planning of these stages is presented in this case study. It is applied to determine the daily allocation of products to processes for a major electronic scrap recovery centre that faces limited processing capacities and market restrictions. The optimization calculations covering typical discarded electronic products to be recycled in the related centre lead to a relevant improvement of the economic success. RID="*" ID="*" The authors would like to thank the German “Bundesministerium für Bildung und Forschung” (Federal Ministry of Education and Research) for supporting the research project “Substance Flow Oriented Closed Loop Supply Chain Management in the Electrical and Electronic Equipment Industry (STREAM)rdquo;. Correspondence to: T. Spengler     

Assessment of myocardial lesion size during in vitro radio frequency catheter ablation

We report our experience with a system that utilizes changes in several biophysical characteristics of cardiac tissue to determine lesion formation and to estimate lesion size both on and off-line in vitro during radio frequency (RF) energy delivery. We analyzed the reactive and resistive components of tissue impedance and tracked the change of phase angle during RF ablation. We correlated the amount of tissue damage with these and other biophysical parameters and compared them with off-line analysis. We found that there are irreversible changes in the reactive and resistive components of impedance that occurred during tissue ablation. The irreversible changes of these components are greater in magnitude, and correlate better with the size of lesions than that of impedance alone that is currently used. Numerically, the best single on-line and off-line correlation for combined perpendicular and parallel electrode orientation was with phase angle. On-line and off-line capacitance and susceptance correlations were essentially similar suggesting that they may be useful as lesion size predictors, given these parameter's persistent change without temperature sensitivity. This study indicates that it is technically feasible to assess lesion formation using biophysical parameters.     

Theoretical calculations and performance results of a PZT thin film actuator

High piezoelectric coupling coefficients of PZT-based material systems can be employed for actuator functions in micro-electro-mechanical systems (MEMS) offering displacements and forces which outperform standard solutions. This paper presents simulation, fabrication, and development results of a stress-compensated, PZT-coated cantilever concept in which a silicon bulk micromachining process is used in combination with a chemical solution deposition (CSD) technique. Due to an analytical approach and a finite element method (FEM) simulation for a tip displacement of 10 /spl mu/m, the actuator was designed with a cantilever length of 300 /spl mu/m to 1000 /spl mu/m. Special attention was given to the Zr/Ti ratio of the PZT thin films to obtain a high piezoelectric coefficient. For first characterizations X-ray diffraction (XRD), scanning electron microscopy (SEM), hysteresis-, current-voltage I(V)and capacitance-voltage C(V)-measurements were carried out.     

An atmospheric pressure glow discharge optical emission source for the direct sampling of liquid media

A glow discharge optical emission spectroscopy (GD-OES) source that operates at atmospheric pressure is described. This device utilizes an electrolytic solution containing the analyte specimen as one of the discharge electrodes. The passage of electrical current (either electrons or positive ions) across the solution/gas phase interface causes local heating and the volatilization of the analyte species. Collisions in the discharge region immediately above the solution surface result in optical emission that is characteristic of the analyte elements. Operation of this device with the analyte solution acting as either the cathode or anode is demonstrated. Current-voltage (i-V) plots reveal abnormal glow discharge characteristics, with operating parameters being dependent on the electrolyte concentration (i.e., solution conductivity) and the gap between the solution surface and the counterelectrode. Typical conditions include discharge currents of 30-60 mA, and potentials of 500-900 V. Electrolyte solutions having pH, pNa, or pLi values of 0.5-2 and interelectrode gaps of 0.5-3 mm produce stable plasmas in which the analyte solutions flow at rates of up to 3.0 mL/min. Preliminary limits of detection are determined for the elements Na, Fe, and Pb to be in the range of 11-14 ppm (approximately 60 ng) for 5-microL sample volumes.     

iMLP: Applying Multi-Layer Perceptrons to Interval-Valued Data

Interval-valued data offer a valuable way of representing the available information in complex problems where uncertainty, inaccuracy or variability must be taken into account. In addition, the combination of Interval Analysis with soft-computing methods, such as neural networks, have shown their potential to satisfy the requirements of the decision support systems when tackling complex situations. This paper proposes and analyzes a new model of Multilayer Perceptron based on interval arithmetic that facilitates handling input and output interval data, but where weights and biases are single-valued and not interval-valued. Two applications are considered. The first one shows an interval-valued function approximation model and the second one evaluates the prediction intervals of crisp models fed with interval-valued input data. The approximation capabilities of the proposed model are illustrated by means of its application to the forecasting of daily electricity price intervals. Finally, further research issues are discussed. Research funded by Universidad Pontificia Comillas.     

An Asymptotically Efficient Simulation-Based Algorithm for Finite Horizon Stochastic Dynamic Programming

We present a simulation-based algorithm called "Simulated Annealing Multiplicative Weights" (SAMW) for solving large finite-horizon stochastic dynamic programming problems. At each iteration of the algorithm, a probability distribution over candidate policies is updated by a simple multiplicative weight rule, and with proper annealing of a control parameter, the generated sequence of distributions converges to a distribution concentrated only on the best policies. The algorithm is "asymptotically efficient," in the sense that for the goal of estimating the value of an optimal policy, a provably convergent finite-time upper bound for the sample mean is obtained     

Protactinium-231: A new radionuclide for AMS

For the first time, an AMS system was used to determine concentrations of the actinide Protactinium-231. ²³¹Pa has widespread applications in the earth sciences. It can be used for U-series disequilibrium dating, and ²³¹Pa is an important tracer in Paleoceanography. The Pa isotopes were measured with the compact ETH/PSI-AMS facility TANDY operating at about 300 kV. The linearity of the AMS is documented with two standard-dilution experiments and first measurements of natural samples from very different climate archives are presented. Our results show that it is possible to determine ²³¹Pa amounts in the lower femtogram (1 fg = 10⁻¹⁵ g) range with the TANDY. In natural samples, ²³¹Pa concentrations between 1 and 4 pg/g (1 pg = 10⁻¹² g) were measured with an average total error of 3% (one sigma). The average over all reproducibility of these first measurements was better than 2% with clear potential for improvement.     

A randomized controlled trial of goal choice interventions for alcohol use disorders among men who have sex with men.

This study tested the efficacy of behavioral treatments for alcohol use disorders (AUD) among men who have sex with men (MSM) and who are at risk for HIV transmission. HIV-negative MSM with current AUD (N = 198) were recruited, offered treatment focused on reducing drinking and HIV risk, and followed during treatment and 12 months posttreatment. Participants (n = 89) accepted treatment and were randomized to either 4 sessions of motivational interviewing (MI) or 12 sessions of combined MI and coping skills training (MI + CBT). Other participants (n = 109) declined treatment but were followed, forming a non-help-seeking group (NHS). MI yielded significantly better drinking outcomes during the 12-week treatment period than MI + CBT, but posttreatment outcomes were equivalent. NHS participants significantly reduced their drinking as well. Service delivery and treatment research implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Four practical and conceptual assessment issues that evaluators should address in capital case mental retardation evaluations.

What unique assessment issues do evaluators face when conducting mental retardation evaluations in capital cases? This article describes 4 assessment issues and reports how 20 evaluators in 1 state have approached them: (a) What methods are appropriate for evaluating adaptive functioning in this context? (b) Should information about criminal behavior be used as evidence of adaptive functioning? (c) Should correctional officers serve as informants regarding adaptive behavior? and (d) How should the Flynn effect influence the interpretation of intelligence test scores? Implications for practice are that practitioners should expect to be asked about the relation between criminal behavior and adaptive functioning, must think carefully about the validity of tests of adaptive functioning for inmates, and must be knowledgeable about the current state of Flynn effect research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The “root” experiment of the “cervantes” spanish soyuz mission: Cell proliferation and nucleolar activity alterations in arabidopsis roots germinated in real or simulated microgravity

In an experiment conducted in the “Cervantes” Spanish Soyuz Mission, a 10-day flight to the International Space Station, Arabidopsis seeds were germinated, seedlings grew for 4 days at 22ºC, and they were fixed in flight with paraformaldehyde. A ground 1 g control experiment was replicated, and an additional experiment in simulated microgravity, using a Random Positioning Machine, was performed in the same conditions. Structural, morphometric and immunocytochemical data were compared. Glutaraldehyde-fixed seedlings similarly grown in the Space Shuttle (STS-84 Mission) were also used for ultrastructural and morphometric studies. Seedlings grown for 4 days in real or simulated weightlessness showed a longer size than the ground 1 g control. Root meristematic cells showed an enhanced proliferating rate, but ribosome biogenesis was reduced, as inferred from the nucleolar size and from the levels of the nucleolar protein nucleolin. This could be the consequence of the acceleration of the cell cycle, with shortening of its phases. Weightlessness induces stress in the plant, influencing cellular processes decisive for development and morphogenesis. This stress may endanger the plant and would require the action of compensating specialized defence mechanisms.