Improving traceability in continuous processes using flow simulations

Traceability is normally difficult to achieve in continuous processes, since there are no natural batch structures. In this article, we demonstrate flow-based simulation using process data to improve traceability in a continuous pelletising process. Using the simulation model, the engineers could test the impacts of process disturbances, identify cause and effect relations and aid control in case of process disturbances. In a field trial where the chemistry of an additive was varied during production of a special product, the simulation forecasts predicted the level of the chemical content after the plant within the errors that the engineers found acceptable.     

Aging male bodies,health and the reproduction of age relations

This article explores the ways in which a group of male factory workers uses bodies as bases for hierarchical categorization of men by age in their talk of mundane aspects of their lives. Analysis of interviews about health (4 focus groups and 5 personal interviews) with Finnish working-class men under 40 years old shows that they portray age groups to which they do not belong as careless, even irresponsible toward health and its maintenance. As they categorize youth and old people by age, they leave themselves unmarked by it, providing no vocabulary to describe their own group. Despite their tendency to distance themselves particularly from old people, they also distinguish among older men by familiarity, providing relatively nuanced accounts of their fathers' aging. We discuss the marking of age groups in terms of social inequality and talk of fathers in terms of intergenerational relations. Even family ties among men of diverse ages involve ageism, which familiarity serves both to mitigate and to make less visible. This article documents the maintenance of age inequality in everyday, mundane behavior.     

Improving confidence in tree species selection for challenging urban sites: a role for leaf turgor loss

High species diversity is argued to be the most important requisite for a resilient urban forest. In spite of this, there are many cities in the northern hemisphere that have very limited species diversity within their tree population. Consequently, there is an immense risk to urban canopy cover, if these over-used species succumb to serious pests or pathogens. Recognition of this should motivate the use of less commonly used species. Analysis of plant traits, such as the leaf water potential at turgor loss (Ψ_P0), can provide useful insights into a species’ capacity to grow in warm and dry urban environments. Therefore, the aim of this study was to evaluate Ψ_P0 of 45 tree species, the majority of which are rare in urban environments. To help evaluate the potential for using Ψ_P0 data to support future decision-making, a survey of professionals engaged with establishing trees in urban environments was also used to assess the relationship between the measured Ψ_P0 and the perceived drought tolerance of selected species. This study demonstrates that Ψ_P0 gives strong evidence for a species’ capacity to tolerate dry growing conditions and is a trait that varies substantially across species. Furthermore, Ψ_P0 was shown to closely relate to the experience of professionals involved in establishing trees in urban environments, thus providing evidence of its practical significance. Use of plant traits, such as Ψ_P0, should, therefore, give those specifying trees confidence to recommend non-traditional species for challenging urban environments.     

Decentralized WIP-oriented manufacturing control (DEWIP)

DEWIP is a manufacturing control system for job shop environments aiming at achieving short and reliable lead times by establishing WIP control loops between the manufacturing work centres. The paper describes the mode of function, the setting of parameters and simulation results of the new manufacturing control system. The setting of parameters is done with the aid of the funnel model and the theory of logistic operating curves, both developed at the Institute of Production Systems at the University of Hanover. The simulation is conducted using industrial data and makes it possible to assess DEWIP with regard to lead times, WIP level, performance and schedule reliability. DEWIP is compared both with an uncontrolled process and with the manufacturing control systems Load oriented order release (LOOR), Conwip and Polca. The results suggest that DEWIP and the models employed for the setting of parameters are suitable for job shop production and therefore offer a valuable alternative to prevailing centralized manufacturing control systems.     

Applying stage-gate processes to technology development—Experience from six hardware-oriented companies

The stage gate model has been proposed for application to uncertain technology development. Reports on industrial experience from such implementations are quite limited, however. This led us to explore in six companies what adaptations have been made to facilitate the model's usefulness for technology development and the companies’ experiences from their practical application of the model. Our results indicate that aspects proven important for the operational success, or failure, of the model include the level of adaptation to the characteristics of technology development and a more flexible use than that normally found in product development.     

Editorial

Ohne Zusammenfassung     

Medical impairing injuries among Swedish firefighters

Using insurance data, medically impairing injuries sustained by 111 firefighters were analyzed. The injury incidence per year among full-time working firefighters was 39 per 10 000, and among part-time working firefighters 6 per 10 000. More than half (51%) were injured during fitness training, 14% during job training, and 13% during emergency response, while 4% were injured in traffic crashes and 18% in other injury events. Soccer and floorball caused 82% of all fitness injuries, of which more than half were meniscal or sprain injuries of knees or ankles. None of those injured during emergency response suffered from burn injuries, however during job training 4 sustained burns. Less injurious fitness training and practice activities could greatly reduce impairing injuries among firefighters and consequently reduce economical losses and disability.