The Fourth ECMI Conference on Industrial Mathematics took place at Strobl in Aus­ tria, May 29-June 2, 1989. The conference was devoted to the exchange of ideas, models and methods from various fields of industrial applications of mathematics. About 140 people from 21 countries attended the meeting. The aim was to bring together peo­ ple from industry and from university. In this respect the organizers were only partly successful!. The participance of about 20 people from industry shows that there is still much work to be done to increase the acceptance from this side. 72 speakers presented their results as invited or contributed lectures, or in the frame of 2 minisymposia. One minisymposium was organized by Heinz W. Engl and focused on steel processing, the other one, organized by Hansjorg Wacker, dealt with chemical engineering. These proceedings consist of 56 papers. The articles within each of the sections: Invited Lectures, Minisymposium Steel Processing, Minisymposium Chemical Engi­ neering, and Contributed Lectures are in alphabetical order of the first author. Exept for the contributions to the minisymposia, which clearly concentrate on the corre­ sponding topics, it is hard to find a reasonable classification of the papers . This, we believe, is typical for industrial mathematics and underlines the vast variety of fields where mathematics could be used to support problem solving. We would like to acknowlegde the valuable work of the referees of the articles who certainly helped to improve the quality of this volume.

Invited Lectures.- On a Mathematical Model for the Crystallization of Polymers.- Remarks on New Mathematical Problems Arising in the Context of Information Technology.- Time Division Multiple Access Systems and Matrix Decomposition.- Fresh Breeze around the Ivory Tower - Current Trends in Austrian Higher Education.- Determination of the Transient Thermal Behaviour of Thyristors with Cooling Devices (abstract).- Mathematics for Industry.- Mathematical Problems in Research at HILTI.- Minisymposium: Steel Processing.- Water Droplet Cooling of Galvanised Iron.- A Mathematical Model for the Calculation of Cooling Criteria for Round Bloom.- Automatic Secondary Cooling Control for the Continuous Casting Process of Steel.- Some Problems of Identification and Control Arising from Cooling Rolled Wires.- Minisymposium: Chemical Engineering.- Numerical Simulation of Emulsion Liquid Membrane Permeation.- The Lay-out of Reactive Extractors.- The Simulation of a Co-Current Bubble Reactor.- A Numerical Model for Calculation of a Counter Current Heat Exchanger.- Contributed Lectures.- Modelling Oxygen Supply in Spheroids of Tumor Cells.- On a Numerical Method for Variable Heat Flow through External Walls.- Optimization of a Solar Domestic Hot-Water System.- The Fluttering of Fibres in Airspinning Processes.- A Numerical Model for Electromagnetic Casters.- On Consistent Initialization of Differential-Algebraic Equations with Discontinuities.- On the Generation of Optical Solitons.- Mathematical Models for the Diffusion of Innovations.- Image Segmentation by Minimum Information Loss (abstract).- A Brief Mathematical Analysis of Electrochemical Machining Problems.- A Mathematical Model for the Production of Bimetallic Strip.- Computing Guaranteed Error Bounds for Problems in RenewalTheory.- Threshold Accepting Algorithms for 0-1 Knapsack Problems.- Digital Topology in Document Processing.- Modelling the Rheology of a Coal-Water Slurry.- Nonorthogonal Expansions of Signals and Some of their Applications (abstract).- Two-Phase Flow Methodology and Modelling.- Maximum Expected Information (MEI) Discretization Method for Spatial Data Analysis (abstract).- Automatic Mesh Generation for 3D Domains with Application in Fluid Mechanics, Structures, Electrotechnics and Aerospace Problems.- Quality Control of Artificial Fabrics (abstract).- Developing a Unidimensional Simulation Model for Producing Silicon in an Electric Furnace.- Numerical Study of the Nonlinear Barotropic Instability of Rossby Wave Motion.- The Method of Region Analysis and its Application for Optimal Control Problems of Hydroelectric Power Plants.- Stochastic Modelling of the Dielectric Relaxation in Condensed Matter (abstract).- A Calculation and Contour Plotting System for Flame Temperatures.- On the Taper Curves in the Forest Industry.- Analytical Three-Dimensional Stress Distribution in the Healthy Hip Joint.- Torsional Vibrations in a Crank Shaft.- An Adaptive Finite Element Method for Stefan Problems.- The Theoretical Ecology of Coccidia with Reference to Poultry Production.- A Dynamic Two-Phase Flow Model for a Purification Plant.- Exchange of Parametric Curve and Surface Geometry between Computer Aided Design Systems.- Fairing of Ship Lines with Mechanical Splines.- Numerical Simulation of the Stretching Behavior of Polymeric Liquids by Nonlinear Volterra Integrodifferential Equations with Boundary Conditions.- 3-D-Fitting of Blades and Vanes.- Development of a Method for Electrical Load Forecasting and its Implementation Using Expert System Techniques.- Fibre Drying.- OptimalExtension of a System of Hydro Energy Storage Plants.- Modelling Separated Flows.- On the Impact of Rigid Bodies with Small Deadrise Angle onto Inviscid, Incompressible Fluid.- B-Spline Library for Mathematical Modelling and Solving of Scientific and Industrial Problems.