Stabilized Kuramoto-Sivashinsky equation: A useful model for secondary instabilities and related dynamics of experimental one-dimensional cellular flows

We report numerical simulations of one-dimensional cellular solutions of the stabilized Kuramoto-Sivashinsky equation. This equation offers a range of generic behavior in pattern-forming instabilities of moving interfaces, such as a host of secondary instabilities or transition toward disorder. We compare some of these collective behaviors to those observed in experiments. In particular, destabilization scenarios of bifurcated states are studied in a spatially semi-extended situation, which is common in realistic patterns, but has been barely explored so far.Comment: 4 pages, 14 figure

Influence of spatial variability of hydraulic characteristics of soils on surface parameters obtained from remote sensing data in infrared and microwaves

The correct interpretation of thermal and hydraulic soil parameters infrared from remotely sensed data (thermal infrared, microwaves) implies a good understanding of the causes of their temporal and spatial variability. Given this necessity, the sensitivity of the surface variables (temperature, moisture) to the spatial variability of hydraulic soil properties is tested with a numerical model of heat and mass transfer between bare soil and atmosphere. The spatial variability of hydraulic soil properties is taken into account in terms of the scaling factor. For a given soil, the knowledge of its frequency distribution allows a stochastic use of the model. The results are treated statistically, and the part of the variability of soil surface parameters due to that of soil hydraulic properties is evaluated quantitatively

Sensible and latent heat flux from radiometric surface temperatures at the regional scale: methodology and validation

The CarboEurope Regional Experiment Strategy (CERES) was designed to develop and test a range of methodologies to assess regional surface energy and mass exchange of a large study area in the south-western part of France. This paper describes a methodology to estimate sensible and latent heat fluxes on the basis of net radiation, surface radiometric temperature measurements and information obtained from available products derived from the Meteosat Second Generation (MSG) geostationary meteorological satellite, weather stations and ground-based eddy covariance towers. It is based on a simplified bulk formulation of sensible heat flux that considers the degree of coupling between the vegetation and the atmosphere and estimates latent heat as the residual term of net radiation. Estimates of regional energy fluxes obtained in this way are validated at the regional scale by means of a comparison with direct flux measurements made by airborne eddy-covariance. The results show an overall good matching between airborne fluxes and estimates of sensible and latent heat flux obtained from radiometric surface temperatures that holds for different weather conditions and different land use types. The overall applicability of the proposed methodology to regional studies is discusse

Influence of humidity on granular packings with moving walls

A significant dependence on the relative humidity H for the apparent mass (Mapp) measured at the bottom of a granular packing inside a vertical tube in relative motion is demonstrated experimentally. While the predictions of Janssen's model are verified for all values of H investigated (25%< H <80%), Mapp increases with time towards a limiting value at high relative humidities (H>60%) but remains constant at lower ones (H=25%). The corresponding Janssen length is nearly independent of the tube velocity for H>60% but decreases markedly for H=25%. Other differences are observed on the motion of individual beads in the packing. For H=25%, they are almost motionless while the mean particle fraction of the packing remains constant; for H>60% the bead motion is much more significant and the mean particle fraction decreases. The dependence of these results on the bead diameter and their interpretation in terms of the influence of capillary forces are discussed.Comment: 6 pages, 6 figure

A rare early-type star revealed in the Wing of the Small Magellanic Cloud

Sk 183 is the visually-brightest star in the N90 nebula, a young star-forming region in the Wing of the Small Magellanic Cloud (SMC). We present new optical spectroscopy from the Very Large Telescope which reveals Sk 183 to be one of the most massive O-type stars in the SMC. Classified as an O3-type dwarf on the basis of its nitrogen spectrum, the star also displays broadened He I absorption which suggests a later type. We propose that Sk 183 has a composite spectrum and that it is similar to another star in the SMC, MPG 324. This brings the number of rare O2- and O3-type stars known in the whole of the SMC to a mere four. We estimate physical parameters for Sk 183 from analysis of its spectrum. For a single-star model, we estimate an effective temperature of 46+/-2 kK, a low mass-loss rate of ~10^-7 Msun yr^-1, and a spectroscopic mass of 46^+9_-8 Msun (for an adopted distance modulus of 18.7 mag to the young population in the SMC Wing). An illustrative binary model requires a slightly hotter temperature (~47.5 kK) for the primary component. In either scenario, Sk 183 is the earliest-type star known in N90 and will therefore be the dominant source of hydrogen-ionising photons. This suggests Sk 183 is the primary influence on the star formation along the inner edge of the nebula.Comment: Accepted by ApJ, 10 pages, 7 figures, v2 after proof

Does Ergonomics Improve Product Quality and Reduce Costs? A Review Article

Competition is an ongoing challenge confronting industrial corporations, particularly automobile manufacturing. Striving to improve product quality and productivity, automotive industries have used different quality management approaches, such as reduced variability, total quality management, and lean management, over recent years. Furthermore, incorporating proactive ergonomics such as physical and organizational ergonomics and psychosocial factors into the structure of a company is considered to be a support for productivity and quality. Several studies have shown the effects of ergonomics on better quality. Application of both quality management approaches and ergonomics in an integrated manner in the manufacturing production system is emphasized because they are similar concepts with the same objectives, that is, to improve efficiency. In this study, a comprehensive review was undertaken and 25 studies were reviewed in order to define how integration of an ergonomic approach in the manufacturing production system can reduce defects and improve quality in the production process

Operational leeway in the work situations: Do ergonomic risk assessment tools consider operational leeway for job analysis?

Our study shows that information on operational leeway is limited in the originator articles of the ergonomic risk assessment tools for prevention of musculoskeletal disorders (MSDs). The tools\u27 underlying theoretical models do not consider the indicators of operational leeway, and they cannot determine the sufficiency of the situational operational leeway in a work situation. Consequently, regulation of the activity, which ensures the performance goals and the individual\u27s health, has been overlooked. The lack of literature on the indicators of situational operational leeway is one of the reasons for this deficit. Defining the indicators for this concept would be an innovation in the approach of MSDs risk prevention. Developing empirically the concept of situational operational leeway in the risk assessment tools would help to progress in the current approach of MSDs prevention. This study therefore proposes the indicators of the situational operational leeway to increase the representativeness and reliability of the risk assessment tools for MSDs