872 research outputs found

    Recognising waste use potential to achieve a circular economy

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    Waste management historically focused on the protection of human health and the natural environment from the impacts of littering and dispersion of pollutants. An additional and more recent concern is the resource value of waste. Our analysis shows that the regulatory concept of waste in the European Union, which comprises environmental principles, the legal definition of waste, legal requirements, and policy implementation, is not fit for addressing this concern. The legal definition of waste overlooks the context of waste, fails to consider the interests of the waste user as opposed to the waste holder, and aims to control the impacts of careless discarding rather than stimulating careful discarding. To address these challenges, we suggest a legal requirement to recognise the potential of waste to be used, operationalised by formulating a waste use potential, which expresses how and how much waste can be used as a resource, given enabling conditions. Recognition of waste use potential highlights local opportunities for reuse and recovery, reduces the likelihood of careless discarding, and reveals the interests of possible waste users to the waste holder. The waste use potential may be employed in the formulation and evaluation of policies for industrial and municipal solid waste in a circular economy

    Analyse der Störfestigkeit nichtlinearer Schaltungen gegenüber leitungsgebundenen elektromagnetischen Störungen mit multi-input Wiener/Hammerstein-Modellen

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    In dieser Arbeit wird der Einfluss von leitungsgebundenen Störungen untersucht, welche in einen beliebigen Eingang (Signaleingang, Spannungsversorgung, Masse-Potenzial, etc.) einer Analogschaltung einkoppeln. Die zu untersuchende Schaltung wird dazu durch einen Wiener/Hammerstein-Ansatz als nichtlineares System mit zwei Eingängen modelliert. Mit Hilfe dieses Blockmodells werden analytische Ausdrücke derjenigen Frequenzanteile bestimmt, die durch Intermodulationen zwischen Stör- und Eingangssignal am Ausgang einer Schaltung entstehen.BMBF/03X4604

    Global life cycle paper flows, recycling metrics and material efficiency

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    Despite major improvements in recycling over the last decades, the pulp and paper sector is a significant contributor to global greenhouse gas emissions and other environmental pressures. Further reduction of virgin material requirements and environmental impacts requires a detailed understanding of the global material flows in paper production and consumption. This study constructs a Sankey diagram of global material flows in the paper life cycle, from primary inputs to end-of-life waste treatment, based on a review of publicly available data. It then analyses potential improvements in material flows and discusses recycling and material efficiency metrics. The article argues that the use of the collection rate as a recycling metric does not directly stimulate avoidance of virgin inputs and associated impacts. An alternative metric compares paper for recycling (recovered paper) with total fibrous inputs and indicates that the current rate is at just over half of the technical potential. Material efficiency metrics are found to be more useful if they relate to the reuse potential of wastes. The material balance developed in this research provides a solid basis for further study of global sustainable production and consumption of paper. The conclusions on recycling and efficiency should be considered for improving environmental performance assessment methods

    An identification procedure of multi-input Wiener models for the distortion analysis of nonlinear circuits

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    In this contribution, a system identification procedure of a two-input Wiener model suitable for the analysis of the disturbance behavior of integrated nonlinear circuits is presented. The identified block model is comprised of two linear dynamic and one static nonlinear block, which are determined using an parameterized approach. In order to characterize the linear blocks, an correlation analysis using a white noise input in combination with a model reduction scheme is adopted. After having characterized the linear blocks, from the output spectrum under single tone excitation at each input a linear set of equations will be set up, whose solution gives the coefficients of the nonlinear block. By this data based black box approach, the distortion behavior of a nonlinear circuit under the influence of an interfering signal at an arbitrary input port can be determined. Such an interfering signal can be, for example, an electromagnetic interference signal which conductively couples into the port of consideration

    Elemental and mineralogical composition of metal-bearing neutralisation sludges, and zinc speciation – A review

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    Zinc (Zn) in sludges from neutralisation of acidic emissions is a potential environmental pollutant and an element of interest for recovery. Findings regarding the elemental and mineralogical composition of such wastes were aggregated from the literature and examined together for a better understanding of management options, with a focus on Zn. Zn concentrations ranged from 0.006-22% in 46 acid mine drainage sludges, 0.009%-43% in 72 metal-finishing sludges, 0.024%-11.5% in 32 pyrometallurgical sludges, and 1.71-55.7% in 14 Zn production sludges. The main mineralogical characterization technique was X-ray diffraction, which found the dominant minerals to be calcite, gypsum, quartz, and iron oxides, but could not identify considerable proportions of amorphous phases. More than 60 mineral phases were observed. Crystalline Zn compounds identified included oxides, hydroxides, sulfates, sulfides, and metallic Zn; spinel, olivine and carbonate dominated in pyrometallurgical sludges. Zn may also be present in crystalline phases of low concentration, solid solution, and/or amorphous phases, which could be identified and characterised in more detail using other techniques. Overall, it is concluded that Zn occurs in high concentrations and includes phases that have high potential environmental mobility. Zn recovery seems feasible and would also enable harmless disposal of the residual

    The influence of tDCS on perceived bouncing/streaming

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    Processing ambiguous situations is a constant challenge in everyday life and sensory input from different modalities needs to be integrated to form a coherent mental representation on the environment. The bouncing/streaming illusion can be studied to provide insights into the ambiguous perception and processing of multi-modal environments. In short, the likelihood of reporting bouncing rather than streaming impressions increases when a sound coincides with the moment of overlap between two moving disks. Neuroimaging studies revealed that the right posterior parietal cortex is crucial in cross-modal integration and is active during the bouncing/streaming illusion. Consequently, in the present study, we used transcranial direct current stimulation to stimulate this brain area. In the active stimulation conditions, a 9 cm2 electrode was positioned over the P4-EEG position and the 35 cm2 reference positioned over the left upper arm. The stimulation lasted 15 min. Each participant did the bouncing/streaming task three times: before, during and after anodal or sham stimulation. In a sample of N = 60 healthy, young adults, we found no influence of anodal tDCS. Bayesian analysis showed strong evidence against tDCS effects. There are two possible explanations for the finding that anodal tDCS over perceptual areas did not modulate multimodal integration. First, upregulation of multimodal integration is not possible using tDCS over the PPC as the integration process already functions at maximum capacity. Second, prefrontal decision-making areas may have overruled any modulated input from the PPC as it may not have matched their decision-making criterion and compensated for the modulation

    HIV transmission by human bite: a case report and review of the literature—implications for post-exposure prophylaxis

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    We report a case of a probable HIV-1 transmission by human bite. The analyzed data from ten previously reported suspected or allegedly confirmed HIV transmissions revealed a deep bleeding bite wound as the primary risk factor. A high HIV plasma viral load and bleeding oral lesions are present most of the time during HIV transmission by bite. HIV post-exposure prophylaxis (PEP) should be recommended in case of a bleeding wound resulting from a bite of an HIV-infected person. PEP was missed in this presented case

    Limitations of the waste hierarchy for achieving absolute reductions in material throughput

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    Dematerialization can serve as a measurable and straightforward strategy for sustainability and requires changes in management of material inputs and waste outputs of the economy. Currently, waste man- agement is strongly inspired by the waste hierarchy, an in fl uential philosophy in waste and resource management that prioritizes practices ranging from waste prevention to land fi ll. Despite the inclusion and prioritization of prevention in the hierarchy, the positive contribution of the application of the waste hierarchy to dematerializing the economy is not inevitable, nor has it been conclusively studied. In this paper, the waste hierarchy is analyzed on a conceptual level by studying its original aims, its potential to ful fi ll those aims, and its actual policy implementation. Issues with the hierarchy include limited spec- i fi cation and implementation of prevention, a lack of guidance for choosing amongst the levels of the hierarchy and the absence of a distinction between open-loop and closed-loop recycling. Also, the hi- erarchy only communicates relative priorities and therefore does not support decisions that affect other sectors as well as waste management. The article concludes that the waste hierarchy in its current form is an insuf fi cient foundation for waste and resource policy to achieve absolute reductions in material throughput. Suggested improvements are the adoption of a value-based conception of waste and related collection practices, more stringent and targeted policies on least desirable options like land fi ll, the speci fi cation of waste management targets based on dematerialization ambitions, and the use of the waste hierarchy within a resource productivity-oriented framework

    Modellierung von Quanteneffekten in einem ladungsbasierten MOS-Transistor-Modell zur Simulation von nanoskalierten CMOS-Analogschaltungen

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    Aufgrund der fortschreitenden Miniaturisierung der Bauelemente in CMOS-Schaltungen und den dadurch erreichten Strukturgrößen nehmen quantenmechanische Effekte zunehmenden Einfluss auf die Funktion von Transistoren und damit auf die gesamte Schaltung. Unter Einbeziehung der Energiequantisierung an der Si/SiO<sub>2</sub>-Grenzfläche wird untersucht, wie sich durch eine Modifikation der Beschreibung des Oberflächenpotenzials die Inversionsladung quantenmechanisch formulieren lässt. Im Hinblick auf den Entwurf und die Simulation von CMOS-Analogschaltungen wird dazu ein ladungsbasiertes MOS-Transistor-Modell zugrunde gelegt. Die sich daraus ergebenden Veränderungen für die Kapazitäten und die Inversionsladung werden dabei für die Modellierung des quasiballistischen Drain-Source-Stromes verwendet. Dazu wird innerhalb dieses Modells ein Streufaktor berechnet, mit dem nanoskalierte MOS-Transistoren mit einer Kanallänge von unter 20 nm simuliert werden können. Ausgehend von Parametern eines CMOS-Prozesses werden mit MATLAB die Einflüsse der quantenmechanischen Effekte bei der Skalierung des Transistors analysiert
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