3 research outputs found
Cross-training workers in Dual Resource Constrained systems with heterogeneous processing times
Improving production flexibility in an industrial company by shortening changeover time: a triple helix collaborative project
This chapter presents a triple helix collaborative project carried out through the collaboration of members of three Universities in order to analyze the impact of shortening changeover time on production flexibility in an Industrial Company. The project has been developed for a production company, whose products are fibreboard, hardboard, and soft board products manufactured by a highly specialized Industry using only pure wood fibres. The main reason why it was decided to complete the project was the existence of too long lead times, which meant that many orders were delayed. The main objectives of the project were to reduce changeover times and to increase production flexibility. Therefore, changeover time was analyzed to understand if some activities could be eliminated, moved or simplified. The implemented solution has resulted in shortened lead time, improved workflow, reduced costs of line putting in readiness, standardized changeovers, and has significantly contributed to improving the competitiveness of the Company on the market.This work is supported by Portuguese National Funds through FCT “Fundação para a Ciência e a Tecnologia” under the projects: “Projeto Estratégico–UI 252–2011–2012”, reference PEst-OE/EME/UI0252/2014, and FCOMP-01-0124-FEDER-PEst-OE/EEI/UI0760/2014
Age constraints on faulting and fault reactivation: a multi-chronological approach.
Movement within the Earth’s upper crust is commonly accommodated by faults or shear zones, ranging in scale from micro-displacements to regional tectonic lineaments. Since faults are active on different time scales and can be repeatedly reactivated, their displacement chronology is difficult to reconstruct. This study represents a multi-geochronological approach to unravel the evolution of an intracontinental fault zone locality along the Danube Fault, central Europe. At the investigated fault locality, ancient motion has produced a cataclastic deformation zone in which the cataclastic material was subjected to hydrothermal alteration and K-feldspar was almost completely replaced by illite and other phyllosilicates. Five different geochronological techniques (zircon Pb-evaporation, K–Ar and Rb–Sr illite, apatite fission track and fluorite (U-Th)/He) have been applied to explore the temporal fault activity. The upper time limit for initiation of faulting is constrained by the crystallization age of the primary rock type (known as “Kristallgranit”) at 325 ± 7 Ma, whereas the K–Ar and Rb–Sr ages of two illite fractions <2 μm (266–255 Ma) are interpreted to date fluid infiltration events during the final stage of the cataclastic deformation period. During this time, the “Kristallgranit” was already at or near the Earth’s surface as indicated by the sedimentary record and thermal modelling results of apatite fission track data. (U–Th)/He thermochronology of two single fluorite grains from a fluorite–quartz vein within the fault zone yield Cretaceous ages that clearly postdate their Late-Variscan mineralization age. We propose that later reactivation of the fault caused loss of helium in the fluorites. This assertion is supported by geological evidence, i.e. offsets of Jurassic and Cretaceous sediments along the fault and apatite fission track thermal modelling results are consistent with the prevalence of elevated temperatures (50–80°C) in the fault zone during the Cretaceous