The Role of Debt and Equity Finance over the Business Cycle

The authors show that debt and equity issuance are procyclical for most listed U.S. firms. The procyclicality of equity issuance decreases monotonically with firm size. At the aggregate level, however, the authors' results are not conclusive: issuance is countercyclical for very large firms that, although few in number, have a large effect on the aggregate because of their enormous size. If firms use the standard one-period contract, then the shadow price of external funds is procyclical and the cyclicality decreases with firm size. This property generates equity to be procyclical and--as in the data--the procyclicality decreases with firm size. Other factors that cause equity to be procyclical in the model are a countercyclical price of risk and a countercyclical cost of equity issuance. The model (i) generates a countercyclical default rate, (ii) magnifies shocks, and (iii) generates a stronger cyclical response for small firms, whereas the model without equity does the exact opposite.Financial stability; Business fluctuations and cycles

Cyclical Behavior of Debt and Equity Using a Panel of Canadian Firms

We document the cyclical behavior of debt, equity, and retained earnings for different firm categories using firm-level Canadian data. There is evidence of both procyclical equity and debt issuance for all firm categories but the timing differs. In particular, there is strong evidence that equity issuance increases in anticipation of an expansion. During this phase, some substitution between debt and equity takes place. After the expansion has reached its peak, equity issuance starts to decrease and during this phase there is strong evidence of procyclical debt issuance and some substitution out of equity seems to take place. Retained earnings is procyclical except for small firms.Business fluctuations and cycles

In-process measurements for reactive extrusion monitoring and control

Process monitoring of reactive extrusion is often limited to pressure and temperature measurements at the die. These may be sensitive to fluctuations in the process, but provide limited information on the actual characteristics of the polymer system under manufacture. Consequently, in‐process measurement using spectroscopic and rheometric techniques, among others, are used to monitor the manufacture of several reactive systems. This approach helps minimize the time lag associated with collecting and preparing samples for measurements off‐line, may avoid submitting the sampled material to extra thermal cycles that might change its characteristics, and could support new process‐control paradigms. This chapter summarizes the developments of in‐line and on‐line measuring techniques relevant to reactive extrusion and presents some examples of application

Monitoring of polymer extrusion and compounding processes

This work focuses on monitoring of polymer extrusion and melt compounding using single or twin-screw extruders. Standard extruder instrumentation aims at detecting eventual instabilities in flow and heat transfer in the extruder. Strategies for in-process monitoring considering the actual characteristics of the material being processed are presented and discussed. On-line and in-line approaches are defined. The advantages of sampling along the extruder barrel are demonstrated. Examples of the development and application of in-process optical spectroscopy and rheometry techniques are presented and discussed

EURHEO: the Erasmus Mundus Master in Engineering Rheology

EURHEO (www.eurheo.eu) is a two-year Master course delivered under the prestigious Erasmus Mundus programme. EURHEO aims at offering a pioneer advanced education programme on Rheology and its applications to different Engineering areas. It combines the expertise of six leading European Universities in the field of Rheology (University of Minho (UM - Portugal), the University of Ljubljana (ULJ - Slovenia), the Universidad de Huelva (UHU - Spain), the Kaholieke Universiteit Leuven (KUL - Belgium), the Université catholique de Louvain (UCL - Belgium) and the University of Calabria (UCAL - Italy)) and the syllabus is designed to provide students with the necessary competences to understand the relevance of Rheology in Materials Science and Engineering and apply the knowledge gained in solving real-world Engineering problems both autonomously and included in multidisciplinary research teams. We will present the EURHEO education programme, and the types of grants that Portuguese and Spanish students can apply for. The first scientific EURHEO outputs, namely results from selected Master theses, will be presented in 2 posters which report the research carried out by 2 students at UM.European Union and EACEA for granting project 2008-0099-EURHEO: The Erasmus Mundus Master in Engineering Rheology

A scaling-up methodology for co-rotating twin-screw extruders

Scaling-up of co-rotating twin screw extruders is studied as a multi-objective optimization problem where the aim is to define the geometry/operating conditions of the target extruder that minimize the differences between the values of the performance criteria that depict the reference and target extruders. Three computational experiments are discussed. These preliminary results seem encouraging

Use of multi-objective evolutionary algorithms in extrusion scale-up

Extrusion scale-up consists in ensuring identical thermo-mechanical environments in machines of different dimensions, but processing the same material. Given a reference extruder with a certain geometry and operating point, the aim is to define the geometry and operating conditions of a target extruder (of a different magnitude), in order to subject the material being processed to the same flow and heat transfer conditions, thus yielding products with the same characteristics. Scale-up is widely used in industry and academia, for example to extrapolate the results obtained from studies performed in laboratorial machines to the production plant. Since existing scale-up rules are very crude, as they consider a single performance measure and produce unsatisfactory results, this work approaches scale-up as a multi-criteria optimization problem, which seeks to define the geometry/operating conditions of the target extruder that minimize the differences between the values of the criteria for the reference and target extruders. Some case studies are discussed in order to validate the concept

The use of evolutionary algorithms to solve practical problems in polymer extrusion

This work aims at selecting the operating conditions and designing screws that optimize the performance of single-screw and co-rotating twin-screw extruders, which are machines widely used by the polymer processing industry. A special MOEA, denoted as Reduced Pareto Set Genetic Algorithm, RPSGAe, is presented and used to solve these multiobjective combinatorial problems. Twin screw design is formulated as a Travelling Salesman Problem, TSP, given its discrete nature. Various case studies are analyzed and their validity is discussed, thus demonstrating the potential practical usefulness of this approach

Polymer extrusion: setting the operating conditions and defining the screw geometry

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