Search results

The development of physically‐correct models of granular behaviour under shear deformations must recognize the discrete nature of the medium and the mechanical properties of the constituent grains at the particle level. Numerical simulation of idealized granular materials offers the researcher the possibility of recovering complete information on these systems that can then guide the development of micromechanical‐based models of granular systems. A numerical technique that has proved useful in meeting this goal is the discrete element method (DEM). The computer implementation of this method to observe microfeatures of idealized granular assemblies was first reported in the published literature by Cundall and Strack. Since that time a number of researchers have used the technique to explore the behaviour of idealized granular systems comprising cohesionless assemblies of discs and assemblies of discs comprising indestructible (bonded) contacts. The paper reviews some of the numerical simulation work that has been carried out by the authors to verify stress‐force‐fabric relationships first proposed by Rothenburg and constitutive stress‐strain laws for dense isotropic assemblies of bonded discs. The numerical technique in each case is the same and involves the solution of the equations of motion of each particle using an explicit time/finite difference algorithm which is the essential feature of the DEM.

Nobody concerned with political economy can neglect the history of economic doctrines. Structural changes in the economy and society influence economic thinking and, conversely, innovative thought structures and attitudes have almost always forced economic institutions and modes of behaviour to adjust. We learn from the history of economic doctrines how a particular theory emerged and whether, and in which environment, it could take root. We can see how a school evolves out of a common methodological perception and similar techniques of analysis, and how it has to establish itself. The interaction between unresolved problems on the one hand, and the search for better solutions or explanations on the other, leads to a change in paradigma and to the formation of new lines of reasoning. As long as the real world is subject to progress and change scientific search for explanation must out of necessity continue.

This paper is the result of empirical field research conducted in Alsace, a bi‐cultural area of France controlled by Germany from 1870 to WWI, by France between the World Wars, and by Germany during WWII. The objective of the study is to contribute to the understanding of small‐scale entrepreneurs who traditionally controlled the distribution of livestock in this bi‐cultural and multi‐lingual region.

This paper gives an account of the livestock distribution system, which prevailed in Alsace, until the Second World War. It uses qualitative methodology, based on oral testimonies of retired entrepreneurs and verified by means of triangulation.

The findings in this paper indicate that, in this region of traditional rivalry between French and Germans, the sector was dominated by family enterprises speaking Jédich‐Daitch, serving as a middleman minority, and dealing between French‐speakers and German‐speakers, who did not trade with one another.

This paper shows that, while much literature shows that middleman minorities now exist around the world, it also reveals that the concept of middleman minority existed centuries ago, in the food sector; the arrangement allowed farmers to specialise in agriculture, while specialised entrepreneurs bought and sold livestock and also provided credit to farmers. This paper is of interest to historians and anthropology/management/sociology scholars of entrepreneurship, as well as practitioners in the livestock industry.