Total Cost of Ownership Driven Methodology for Predictive Maintenance Implementation in Industrial Plants

Part 4: Product and Asset Life Cycle Management in Smart Factories of Industry 4.0International audienceThis paper proposes a methodology to drive from a strategic point of view the implementation of a predictive maintenance policy within an industrial plant. The methodology integrates the evaluation of system performances, used to identify the critical components, with simulation and cost analysis. The goal is to evaluate predictive maintenance implementation scenarios based on alternative condition monitoring (CM) solutions, under the lenses of Total Cost of Ownership (TCO). This allows guiding the decision on where in the industrial system to install diagnostic solutions for monitoring of asset health, by keeping a systemic and life cycle-oriented perspective. Technical systemic performances are evaluated through Monte Carlo simulation based on the Reliability Block Diagram (RBD) model of the system. To validate the methodology, an application case study focused on a production line of a relevant Italian company in the food sector is presented

Flexibility in MOFs: Do scalar and group-theoretical counting rules work?

© The Royal Society of Chemistry 2016. We investigate the ability of counting rules drafted from engineering to predict the flexibility or rigidity of bar-and-joint or body-and-joint assemblies representing metal organic frameworks. We show that while scalar counting rules are not reliable, group-theoretical approaches are able to disentangle mechanisms from states of self-stress and to predict the existence of flexible mechanisms. We give several detailed examples of such calculations, highlighting the fact that behind an abstract exterior they are in fact easy to apply and similar to the method used to obtain molecular vibrations. We also correct a slight misinterpretation of the rigidity of IRMOF-1

Critical fields of the ambient pressure stable superconducting state at 8K of the organic metal alphat-(BEDTsingle bondTTF)2I3

Crystals of αt-(BEDT-TTF)2I3 are organic metals with a stable 8K superconducting transition at ambient pressure. The upper critical fields Hc2 of αt-(BEDT-TTF)2I3 were determined in dependence of the temperature and of the angle of the magnetic field with respect to the variuos cristal axes, by measuring the mid-transition of the resistivity as well as of the rf penetration depth (ac-susceptibility). The values obtained by both methodes agree quite well. The data were analised with the anisotropic effective mass model. The highly two dimensional nature of the metal is confirmed, but in the temperature dependence of the critical field with the magnetic field parallel to the ab-plane a crossover from a three- to a two-dimensional behaviour is observed

Plasma production by secondary impacts - implications for velocity-measurements by in-situ dust detectors

A number of in-situ cosmic dust detectors derive the dust particle velocities from measurement of the risetimes of the impact plasma signal. Extensive calibration of these instruments has established a reliable empirical relationship but a quantitative explanation has not been available, with the result that confidence in flight data outside the range of the calibration data is hard to assess. Recent measurements taken at the dust accelerator facilities at the University of Kent (UK) and at MPI-K (Germany), supported by a theoretical analysis, have demonstrated that the relationship results from the time-spread of secondary impacts coupled with the mobility of ions in the impact plasma cloud, which is in rum determined by the magnitude and geometry of the applied electric field and on the ion species present Results of the current investigations are presented, and the implications of measurements based on this principle at high particle velocities, at masses unobtainable in calibration studies, and for other instrument geometries, are considered

Microwave conductivity in the pure and iodine-doped organic conductor alpha-(BEDT-TTF)2I3

The microwace conductivity in dependence of temperature was measured on pure and iodine doped crystals of α-(BEDT-TTF)2I3 along the stack direction [100] and perpendictular to it [010]. The exposure times to iodine were varied in many steps between 2 min and 360 min. The contacltess microwave technique enables to keep the same crystal in ech case throuhout all measurements. - The results show that the microwave conductivity vs. temperature is not influenced distinctly by iodine doping. Only alt the onset of the plateau range immediately belwo the metal-ionisator transition ant 135 K a small enhancement of the conductivity is found for exoosure times lager than 60 min. - In no case a transition to a superconductiong state is pbwerved. Therefore recently reported superconductivity may be due to surface effects

Electric conductivity and thermoelectric power of various polypyrroles

The dc-conductivity and thermoelectric power of electrochemically prepared polypyrroles have been investigated in the temperature range between 300 K and 1.3 K on unaged, aged (24–120 days at 80°C in air) and chemically modified samples. The linear temperature dependence of the thermopower of unaged polypyrroles demonstrates clearly the contribution of metallic regions to the electronic transport properties. The temperature dependence of the conductivity of the polypyrroles investigated corresponds to that predicted by the variable range hopping model