Corrosion of galvanised steel under an electrolytic drop

Described here for the first time is an investigation of the local corrosion behaviour of galvanized steel using an electrolytic droplet comprising chloride and sulphate ions. The maximal height of the electrolytic layer and the diameter varied between 500-1100 μm with a total diameter between 1.47-3.35 mm, respectively. These measurements were possible by using microelectrodes as reference and counter electrodes, which could be inserted into the electrolyte droplet thus forming an electrochemical microcell. Polarization curves as well as electrochemical impedance spectroscopy plots were recorded under the electrolyte droplet configuration allowing the determination of the polarisation resistance R_p and the proportionality constant k of the Stern and Geary equation. The influence of temperature, chloride concentration, pH and the thickness of the electrolytic layer on the corrosion rate of galvanised steel were studied.     

Layers of shared and cooperative control,assistance, and automation

Cognition, Technology & Work - Over the last centuries, we have experienced scientific, technological, and societal progress that enabled the creation of intelligent-assisted and automated...     

New risk assessment approach for systemic insecticides: the case of honey bees and imidacloprid (Gaucho)

The procedure to assess the risk posed by systemic insecticides to honey bees follows the European Directives and depends on the determination of the Hazard Quotient (HQ), though this parameter is not adapted to these molecules. This paper describes a new approach to assess more specifically the risk posed by systemic insecticides to honey bees with the example of imidacloprid (Gaucho). This approach is based on the new and existing chemical substances Directive in which levels of exposure (PEC, Predicted Exposure Concentration) and toxicity (PNEC, Predicted No Effect Concentration) are compared. PECs are determined for different categories of honey bees in relation to the amounts of contaminated pollen and nectar they might consume. PNECs are calculated from data on acute, chronic, and sublethal toxicities of imidacloprid to honey bees, to which selected assessment factors are applied. Results highlight a risk for all categories of honey bees, in particular for hive bees. These data are discussed in the light of field observations made on honey bee mortalities and disappearances. New perspectives are given to better determine the risk posed by systemic insecticides to honey bees.     

High Power Electromagnetic Waves Exposure of Healthy and Tumor Bearing Mice: Assessment of Effects on Mice Growth,Behavior, Tumor Growth,and Vessel Permeabilization

High power radiofrequencies may transiently or permanently disrupt the functioning of electronic devices, but their effect on living systems remains unknown. With the aim to evaluate the safety and biological effects of narrow-band and wide-band high-power electromagnetic (HPEM) waves, we studied their effects upon exposure of healthy and tumor-bearing mice. In field experiments, the exposure to 1.5 GHz narrow-band electromagnetic fields with the incident amplitude peak value level in the range of 40 kV/m and 150 MHz wide-band electric fields with the amplitude peak value in the range of 200 kV/m, did not alter healthy and tumor-bearing animals’ growth, nor it had any impact on cutaneous murine tumors’ growth. While we did not observe any noticeable behavioral changes in mice during the exposure to narrow-band signals when wide-band HPEM signals were applied, mice could behave in a similar way as they respond to loud noise signals: namely, if a mouse was exploring the cage prior to signal application, it returned to companion mates when wide-band HPEM signals were applied. Moreover, the effect of wide-band signals was assessed on normal blood vessels permeability in real-time in dorsal-chamber-bearing mice exposed in a pilot study using wide-band signal applicators. Our pilot study conducted within the applicator and performed at the laboratory scale suggests that the exposure to wide-band signals with the amplitude of 47.5 kV/m does not result in increased vessel permeability.     

Surface physicochemical analysis of natural Lactococcus lactis strains reveals the existence of hydrophobic and low charged strains with altered adhesive properties

The cell surface physicochemical properties of 50 Lactococcus lactis strains of different subspecies and isolated from different origins (dairy, vegetal and animal) were examined. Cell surface hydrophobicity and Lewis acid-base properties were evaluated by affinity measurements to solvents in a partitioning test, while the global electrical charge of the cells was assessed by micro-electrophoresis using a laser zeta-meter. A global multivariate analysis of the results revealed a high natural diversity of L. lactis cell surface properties. While 52% of the strains present a hydrophilic and electronegative cell wall surface, a group of strikingly hydrophobic strains (12% of the strains) and a group of strains with unusual low charged surface (18%) were identified. Adhesion on polystyrene microtitre plates was evaluated for twelve strains selected from the multivariate analysis as representatives of the various observed cell wall surface physicochemical patterns. A significant correlation between adhesion, hydrophobicity and low electronegativity was observed when adhesion was performed in a low ionic strength suspending medium. The most adhesive strains were hydrophobic or low charged. The presence of repulsive electrostatic interactions led to a decrease in adhesion of the most negatively charged hydrophilic strains. The present study highlights the diversity of L. lactis cell surface physicochemical properties, diversity that could not be connected to the origin or to the subspecies of the strains.     

Some experiments on the detection of three-dimensional motion of rigid objects in blocks world

The present paper describes some major steps in our experiment of a two-frame based approach analysis. Its application deals with 3-D time-varing scene analysis. The entire analysis process can be divided into several major steps. Here, we are concerned with four main steps: preprocessing, knowledge representation, features matching and motion estimation. The work is directly related to the problem encountered by researchers in machine intelligence area where a vision system is indispensable. For each step, experimental results are given to illustrate the performance of the algorithms of processing. Furthermore, the implemented algorithms provide somewhat versatility and flexibility in the sense that they can be applied to other tasks of scene analysis, such as: stereo vision, object recognition and dynamic scene segmentation since the problem in determining the movement of an object using successive images is similar in many ways to the problem met in optic flow analysis and stereopsis. Finally, it should be pointed out that a vision system can be easily built when combining all of these available algorithms.     

Importance and estimation of aerosol vertical structure in satellite ocean-color remote sensing

The vertical distribution of absorbing aerosols affects the reflectance of the ocean-atmosphere system. The effect, due to the coupling between molecular scattering and aerosol absorption, is important in the visible, especially in the blue, where molecular scattering is effective, and becomes negligible in the near infrared. It increases with increasing Sun and view zenith angles and aerosol optical thickness and with decreasing scattering albedo but is practically independent of wind speed. Relative differences between the top of the atmosphere reflectance simulated with distinct vertical distributions may reach approximately 10% or even 20%, depending on aerosol absorption. In atmospheric correction algorithms, the differences are directly translated into errors on the retrieved water reflectance. These errors may reach values well above the 5x10(-4) requirement in the blue, even for small aerosol optical thickness, preventing accurate retrieval of chlorophyll-a [Chl-a] concentration. Estimating aerosol scale height or altitude from measurements in the oxygen A band, possible with the polarization and directionality of the Earth's reflectance instrument and medium resolution imaging spectrometer, is expected to improve significantly the accuracy of the water reflectance retrievals and yield acceptable [Chl-a] concentration estimates in the presence of absorbing aerosols.     

MDA Tool Components: a proposal for packaging know-how in model driven development

As the Model Driven Development (MDD) and Product Line Engineering (PLE) appear as major trends for reducing software development complexity and costs, an important missing stone becomes more visible: there is no standard and reusable assets for packaging the know-how and artifacts required when applying these approaches. To overcome this limit, we introduce in this paper the notion of MDA Tool Component, i.e., a packaging unit for encapsulating business know-how and required resources in order to support specific modeling activities on a certain kind of model. The aim of this work is to provide a standard way for representing this know-how packaging unit. This is done by introducing a two-layer MOF-compliant metamodel. Whilst the first layer focuses on the definition of the structure and contents of the MDA Tool Component, the second layer introduces a language independent way for describing its behavior. An OMG RFP (Request For Proposal) has been issued in order to standardize this approach. This work is supported in part by the IST European project “MODELWARE” (contract no 511731) and extends the work presented in the paper entitled “MDA Components: A Flexible Way for Implementing the MDA Approach” edited in proceedings of the ECMDA-FA’05 conference.     

Fuzzy spatial constraints and ranked partitioned sampling approach for multiple object tracking

While particle filters are now widely used for object tracking in videos, the case of multiple object tracking still raises a number of issues. Among them, a first, and very important, problem concerns the exponential increase of the number of particles with the number of objects to be tracked, that can make some practical applications intractable. To achieve good tracking performances, we propose to use a Partitioned Sampling method in the estimation process with an additional feature about the ordering sequence in which the objects are processed. We call it Ranked Partitioned Sampling, where the optimal order in which objects should be processed and tracked is estimated jointly with the object state. Another essential point concerns the modeling of possible interactions between objects. As another contribution, we propose to represent these interactions within a formal framework relying on fuzzy sets theory. This allows us to easily model spatial constraints between objects, in a general and formal way. The association of these two contributions was tested on typical videos exhibiting difficult situations such as partial or total occlusions, and appearance or disappearance of objects. We show the benefit of using conjointly these two contributions, in comparison to classical approaches, through multiple object tracking and articulated object tracking experiments on real video sequences. The results show that our approach provides less tracking errors than those obtained with the classical Partitioned Sampling method, without the need for increasing the number of particles.