Supercritical waste oxidation of aqueous wastes

For aqueous wastes containing 1 to 20 wt% organics, supercritical water oxidation is less costly than controlled incineration or activated carbon treatment and far more efficient than wet oxidation. Above the critical temperature (374 C) and pressure (218 atm) of water, organic materials and gases are completely miscible with water. In supercritical water oxidation, organics, air and water are brought together in a mixture at 250 atm and temperatures above 400 C. Organic oxidation is initiated spontaneously at these conditions. The heat of combustion is released within the fluid and results in a rise in temperature 600 to 650 C. Under these conditions, organics are destroyed rapidly with efficiencies in excess of 99.999%. Heteroatoms are oxidized to acids, which can be precipitated out as salts by adding a base to the feed. Examples are given for process configurations to treat aqueous wastes with 10 and 2 wt% organics

Mikroskopische Modellierung von zeitabhängiger Verkehrsnachfrage und von Verkehrsflußmustern

Es wird ein mikroskopisches Modell zur Verkehrsnachfrage entwickelt. Für alle Personen einer sogenannten synthetischen Bevölkerung werden die Wege eines typischen Werktages prognostiziert, mit den Attributen Abfahrtszeit, Start, Ziel und Verkehrsmittel. Das Modell beruht auf einem aktivitätenbasierten Ansatz, wobei die Aktivitäten aus Erhebungsdaten abgeleitet werden. Dazu werden Tagebuchdaten einer Zeitbudgeterhebung mittels einer Clusteranalyse klassifiziert. Die Zeitverwendungsmuster werden anhand soziodemographischer Merkmale den Personen der synthetischen Bevölkerung zugeordnet. Die Ziele der Wege werden in Abhängigkeit von den Reisezeiten gewählt. Merkmale der Person und desWeges bestimmen dieWahl des Verkehrsmittels. Jeder Pkw kann zu jedem Zeitpunkt nur für höchstens eine Tour genutzt werden. Die Attribute der Wege hängen unter anderem von den Verkehrsbedingungen ab. Durch eine Rückkopplung mit einem Verkehrsfluß- und Umlegungs- Modell, das selbst nicht Gegenstand dieser Arbeit ist, wird ein konsistenter Zustand von Nachfrage, Verkehrsbelastung und den sich ergebenden Reisezeiten erreicht. Die Anwendungsmöglichkeiten des Modells werden am Beispiel der Stadt Köln untersucht. Typische Kenngrößen der Verkehrsnachfrage werden mit empirischen Daten, Daten aus anderen Modellierungen und für verschiedene Modellvarianten verglichen

The use of an e-learning constructivist solution in workplace learning

We wished to investigate whether an e-learning approach which uses constructivist principles can be successfully applied to train employees in a highly specialised skill thought to require expert individuals and extensive prolonged training. The approach involved the development of an e-learning package which included simulations and interactivity, then experimental testing in a case study workplace environment with the collection of both quantitative and qualitative data to assess the effectiveness of the package. Our study shows that this e-learning strategy improved the skills of the inexperienced operator significantly. We therefore propose that such programmes could be used as a work based training aid and used as a model system for the training of employees in complex skilled tasks in the workplace. This research demonstrates that the e-learning can be applied outside the traditional learning environment to train unskilled employees to undertake complex practical tasks which traditionally would involve prohibitively expensive instruction. This work also illustrates that simulations and interactivity are powerful tools in the design of successful e-learning packages in preparing learners for real world practical situations. Finally this study shows that workplace learners can be better served by elearning environments rather than conventional training as they allow asynchronous learning and private study which are valued by employees who have other demands on their time and are more comfortable receiving tuition privately Relevance to industry: E-learning using constructivist principles, and incorporating simulations and interactivity can be used successfully in the training of highly specialised and skilled tasks required in the modern workplace

Identification of Network Externalities in Markets for Non-Durables

This paper introduces a structural econometric model of consumer demand for non-durable goods, which exhibits network externalities. The structural model allows us to identify the parameters, which determine the strength of the externalities in the underlying economic model from the empirical estimation results. The estimates of these parameters can then be employed to test the economic significance of the externalities and the compatibility of networks. The identifying assumption that drives our results is that consumers care about the lagged instead of the current network size. We argue that it does not necessarily bound their rationality. To complete our structural model, we provide an example of functional specification that yields a simple linear stochastic model of demand. Using this functional specification, we identify all structural parameters of the model. In the end, the estimation and the stochastic structure of the resulting econometric model are discussed. ZUSAMMENFASSUNG - ( Identifikation der Netzwerkeffekten in den Märkten für nicht-dauerhafte Güter) Der vorliegende Beitrag stellt ein strukturelles ökonometrisches Modell der Konsumnachfrage für nicht-dauerhafte Güter mit externen Netzwerkeffekten vor. Das strukturelle Modell lässt uns die Parameter von Netzwerkeffekten im zugrunde liegenden ökonomischen Modell empirisch zu identifizieren. Die Schätzer der Strukturparameter könnten für das Testen der Netzwerkkompatibilität und der ökonomischen Signifikanz der Netzwerkeffekte verwendet werden. Für die Identifikation nehmen wir an, dass die Konsumenten die Netzwerksgröße verzögert wahrnehmen. Wir argumentieren, dass diese Annahme nicht notwendigerweise mit irrationalem Verhalten gleichzusetzen ist. Um das strukturelle Modell zu vollständigen, geben wir eine funktionale Spezifikation, aus der ein lineares stochastisches Nachfragemodell folgt. Unter Verwendung dieser Spezifikation sind alle Strukturparameter von dem Modell identifiziert. Zum Schluss diskutieren wir die Schätzung und die stochastische Struktur des sich ergebenden ökonometrischen Modells.Structural Econometric Model, Network Externalities, Innovation Diffusion

Helping Business Schools Engage with Real Problems: The Contribution of Critical Realism and Systems Thinking

The world faces major problems, not least climate change and the financial crisis, and business schools have been criticised for their failure to help address these issues and, in the case of the financial meltdown, for being causally implicated in it. In this paper we begin by describing the extent of what has been called the rigour/relevance debate. We then diagnose the nature of the problem in terms of historical, structural and contextual mechanisms that initiated and now sustain an inability of business schools to engage with real-world issues. We then propose a combination of measures, which mutually reinforce each other, that are necessary to break into this vicious circle – critical realism as an underpinning philosophy that supports and embodies the next points; holism and transdisciplinarity; multimethodology (mixed-methods research); and a critical and ethical-committed stance. OR and management science have much to contribute in terms of both powerful analytical methods and problem structuring methods

Trackability Measurement of Coronary Stent in a Coronary Vessel Modell

The EN 14299 standard describes in vitro tests of stent and stent system which are specified more precisely and cover a number of additional parameters. In this paper examination of bare metal coronary stents are shown, such as the trackability force measurement. The measurement of the system’s trackability was performed using an in vitro coronary vessel model with the method worked out by us. The trackability is a very important property of the stent system