Wear of a chute in a rice sorting machine

In a rice sorting machine, rice grains drop onto and slide down an anodised aluminium chute. The purpose of the chute is to separate the grains and provide a controlled distribution. At the bottom of the chute the grains are examined optically and contaminants or defective grains are removed from the stream by jets of air. The machine has the ability to sort low quality rice which contains a large element of contaminants such as husk. The husk is extremely abrasive and this, along with other factors, can lead to a reduction in the life of the chute by wear of the surface. In this work a failure analysis process was undertaken to establish the nature and causes of the chute surface wear and the mechanisms of material removal. Wear occurs initially at the location where the grains first strike the chute and at subsequent regions down the chute where bounce occurs. An experimental and analytical examination of the rice motion on impacting the chute was also carried out along with some friction testing of potential replacement chute materials. The evidence gathered during the failure analysis along with the experimental analysis was used to propose possible material/design improvements

Performance of the jet Global Sequential Calibration (GSC) in ATLAS

International audienceJet are experimental signatures of quarks and gluons, which are produced in high energy processes such as the hard scattering of partons in pp collisions. Jets are objects reconstructed from the energy signal deposited in the calorimeters by the particles coming from the hadronization of quarks and gluons. Its production cross section is really large, it means they are many channels with jets in the fi nal state. Usually the energy deposited does not correspond to the initial energy carried by the particles, i.e. the response of the calorimeter is di fferent from one. This is due to calorimeter e ffects as dead material, non compensation and crack regions and to jet reconstruction eff ects such as out of cone energy. As a consequence the determination of the jet energy scale and the achievement of the optimal jet energy resolution have become of crucial importance

Scarcity may promote cooperation in populations of simple agents

In the study of the evolution of cooperation, resource limitations are usually assumed just to provide a finite population size. Recently, however, it has been pointed out that resource limitation may also generate dynamical payoffs able to modify the original structure of the games. Here we study analytically a phase transition from a homogeneous population of defectors when resources are abundant to the survival of unconditional cooperators when resources reduce below a threshold. To this end, we introduce a model of simple agents, with no memory or ability of recognition, interacting in well-mixed populations. The result might shed light on the role played by resource constraints on the origin of multicellularity.Comment: 5 pages, 2 figure

Sistemas de Alterta Temprana para Identificar Bancos en Problemas: Aplicacion al Caso Costarricense

This paper examines the importance of effective early warning systems for the prudential supervision of financial intermediaries. Discriminant analysis is used to identify atypical institutions among the Costa Rican private banks. Chi-square tests are used for 1987-1991. The effectiveness of the method is demonstrated by its ability to predict problems in banks that eventually went bankrupt, much earlier than when the authorities had perceived any difficulties