The use of computational fluid dynamics in continuous operation industries have become more prominent in recent times. Proposed system improvements through geometric changes or control strategies can be evaluated within a relatively shorter timeframe. Applications for discrete element methods (DEMs) in real life simulations, however, require validated material-calibration-methods. In this paper, the V-model methodology in combination with direct and bulk calibration approaches were followed to determine material model parameters, to simulate real life occurrences. For the bulk calibration approach a test rig with a containment hopper, deflection plate and settling zone was used. Screened material drains from the hopper, interacts with the deflection plate, and then settles at the material angle of repose. A high-speed camera captured material interaction with the rig, where footage was used during simulation validation. The direct measuring approach was used to determine particle size, shape and density, while confirming friction and restitution coefficients determined in the bulk calibration method. The test was repeated and validated for various geometrical changes. Three categories of validation were established, namely particle speed assessment, -trajectory assessment and -plate interaction assessment. In conclusion, the combination of direct and bulk calibration approaches was significant in calibrating the required material model parameters.

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Peculiar − just before and after the 1789 French Revolution secular and even atheist catechisms and confessions appeared. Within a wider project to study these peculiar documents, in this article it is attempted, by way of introduction, to disclose the nature of catechisms and confessions, by returning to the source: the Jewish- Rabbinical pedagogical tradition, as elaborated in the New Testament – the method of question-and-answer and repetition. I argue that the rabbi-talmid relationship was also adopted by Jesus and the apostles and is neglected in translations of the New Testament. The development of this genre is followed in main traits via Augustine and the Middle Ages, and it is indicated how philosophical-theological influences (Platonism, rhetoric) changed catechetical practice into scholarly continuous narratives, that have been simplified again in rosaries into daily ritual recitals, like in Kalde’s Kerstenspiegel just before the Reformation. Luther and Calvin’s recovery of New Testament practice is briefly indicated, as well as the worldview or ontological basis of their type of catechisms. It is summarily argued that the new worldview which made “nature” into origin and the “civil, rational human” into the final end of progress, accepted a new divinity – the natural-historical world – that required new confessional documents: a confession of science, of the state, the fatherland, the economy, labour, and so forth. The new catechisms and confessions expressly focused on these.

The gas booster station of a steel works has experienced excessive bearing failures since commissioning over two decades ago. This station was designed with redundancy, allowing for automatic switch-over between two gas booster fans. Bearing failures were observed, on average once every 15.7 days, with instances where both fans experienced simultaneous downtime. Booster failures resulted in regular station downtime, preventing Coke Oven Gas (COG) transport to an end user. This flammable by-product is used as a heat source and all unutilized volumes are flared, resulting in energy wastages. Furthermore, the absence of COG increases Natural Gas (NG) usage, procured at a cost. Traditional root cause analysis techniques failed to identify the cause of these excessive bearing failures. However, multiple in-depth data analysis studies resulted in a thermodynamic investigation, exposing liquid and solid particles within the COG to be responsible for the failures. This allowed for the design of an in-line particle collector, eliminating excessive failures. Following the particle collector installation, only two strategic bearing changes took place over the next 41 weeks, with reduced bearing vibration levels compared to before. The station experienced no failure downtime during this period, resulting in reduced COG flaring and thus improved energy utilization.