Sökresultat

An analytical stiffness and eigenfrequency model of symmetric parallel 6-6 Stewart platforms (hexapods) is developed based on geometrical design variables to optimize the dynamical performance. The model is based upon Lagrangean dynamics in which the Bryant angles are used for the kinematics formulation. With the analytical eigenfrequency model, optimum stiffness characteristics can be obtained fo

This paper presents current results of an ongoing project to develop a Modelica base library for thermohydraulic systems. There are many different aspects to the development of such a library, fromthe basic physics of fluids and heat to the structuring of model classes in the library and the actual implementation in the Modelica language. The structuring should define interfaces and partial classe

A new chemical reactor, the Open Plate Reactor (OPR), is being developed by Alfa Laval AB. It has a very flexible configuration with distributed inlet ports, cooling zones and internal sensors. This gives the OPR improved control capabilities compared to standard chemical reactors in addition to better heat transfer capacity. In this paper, we address the relationship between the process design,

This paper reports the work on implementing a parallel version of Pascal on a small scale multiprocessor computer. A few simple primitives were included to support parallel programming. The code generation, linking and loading procedures are described. An overview of the hardware is included. Finally some programming experience with the system is reported.

A bilinear system model of a continuous tank reactor from a biotechnology application (F. Mandenius et al., 1987) is studied. The concentrations of the substrate sugar and the product ethanol were measured on-line and utilized to control the flow-rate through the fermenter. The system can be integrated analytically making it possible to describe the reachable sets. Limited controllability is found

Composition is a practice of key importance in software engineering. When real-time applications are composed it is necessary that their timing properties (such as meeting the deadlines) are guaranteed. The composition is performed by establishing an interface between the application and the physical platform. Such an interface does typically contain information about the amount of computing capac

Purpose The aim of this paper is to provide insights into, and perspectives on, the transformation of mindsets for logisticians. We argue that by exploring paradoxes inherent in the efficiency-focused paradigm of today, a strategic mindset can emerge in which central logistics management issues can be addressed, understood, and dealt with in order to enhance supply chain effectiveness and innovati

The direct problem of time dependent electromagnetic scattering in the dispersive sphere is solved by a wave splitting technique. The electric field is expanded in a series involving vector spherical harmonics, leading to a system of wave equations for each term. These systems are reduced to scalar wave equations for each term, which are solved via reflection operators. Some preliminary numerical