Analysis and modeling of green wood milling: Chip production by slabber

During the primary transformation of wood, logs are faced with slabber heads. Chips produced are raw materials for pulp paper and particleboard industries. Efficiency of these industries is partly due to particle size distribution. Command of this distribution is no easy matter because of great dependence on cutting conditions and variability in material. This study aimed a better understanding and predictionof chip fragmentation. It starts with a detailed description of cutting kinematic and interaction between knife and log. This leads to the numerical development of a generic slabber head. Chip fragmentation phenomena were studied through experiments in dynamic conditions. These experiments were carried out thanks to a pendulum (Vc = 400 m/min). It was instrumented with piezoelectric force sensors and high speed camera. Obtained results agreed very well with previous quasi-static experiments

Effect of surface finishing such as sand-blasting and CrAlN hard coatings on the cutting edge’s peeling tools’ wear resistance

The authors would like to thank IonBond (Chassieu-France) who made the sand-blasting treatments and the Regional Council of Burgundy and CTBA (Wood and Furniture Technical Centre) for their financial support.The aim of this study is first to define the effect of a surface finishing such as sand-blasting on the geometry of a wood cutting tool and its wear resistance. In addition, the effectiveness of surface coatings like CrAlN deposited by physical vapor deposition (PVD) technique on conventional and sand-blasted cutting edges was studied. A reference tool and different sand-blasted ones were tested by micro-peeling of beech in a laboratory. Microscopic observations, cutting forces measurement and cutting wear tests were carried out to quantify the behavior of these tools. The results obtained showed that the artificial wear by sandblasting leads to an increase in the wear resistance and coating effectiveness, and completely changes the type of damage done to the tools. The sand-blasting application combined or not with CrAlN coating showed an improvement in the wear resistance of the tools and a modification of the forces during the peeling process. The effectiveness of the CrAlN layers was improved thanks to the sand-blasting treatment and then the duplex ones performed better.Regional Council of Burgundy CTBA (Wood and Furniture Technical Centre

A Grid of 3D Stellar Atmosphere Models of Solar Metallicity: I. General Properties, Granulation and Atmospheric Expansion

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive power to such models of late type stars. We present a grid of improved and more reliable stellar atmosphere models of late type stars, based on deep, 3D, convective, stellar atmosphere simulations. This grid is to be used in general for interpreting observations, and improve stellar and asteroseismic modeling. We solve the Navier Stokes equations in 3D and concurrent with the radiative transfer equation, for a range of atmospheric parameters, covering most of stellar evolution with convection at the surface. We emphasize use of the best available atomic physics for quantitative predictions and comparisons with observations. We present granulation size, convective expansion of the acoustic cavity, asymptotic adiabat, as function of atmospheric parameters. These and other results are also available in electronic form.Comment: 16 pages, 12 figures. Accepted for publication in ApJ, 201

Application of CrAlN coatings on carbide substrates in routing of MDF

This study deals with the development of Chromium Aluminium Nitride (CrAlN) hard coatings (by varying the nitrogen content in the plasma, the target bias voltage, the working pressure and the deposition time) and their characterization by physical and mechanical techniques (XRD, nanoindentation, Young’s modulus, stress, scratch-test, composition, etc.) in order to determine the optimal deposition conditions to apply the coatings to carbide substrates. Moreover, in order to improve the adhesion of the same optimal hard coatings and as it was efficient with Diamond Like Carbon (DLC) coatings, we tried to modify the carbide inserts by chemical attacks with Murakami’s agent before machining. The coated tools (with and without Murakami’s attack) were then tested in routing of Medium Density Fibreboard (MDF). A comparison of the abrasion and shock resistance of the conventional tools with the treated ones, was made. The efficiency of Murakami’s agent was also studied. It was obvious that the coated carbide tools had greater tool life than the untreated ones. Besides, Murakami’s attack was not optimized or not a solution to improve the adhesion of nitride coatings on carbide inserts.Regional Council of Burgundy ISOROY Franc

Manipulating Models Using Internal Domain-Specific Languages

International audienceIn Model-Driven Engineering, a number of external Domain-Specific Languages (DSL) for model manipulation have been proposed. However, they require users to learn new languages that, together with their execution performance, usability and tool support limitations, can significantly contribute to accidental complexities. In this paper, we present an alternative approach based on internal DSLs in Scala for model consistency checking and model transformations for the Eclipse Modeling Framework

ACTRESS: Domain-Specific Modeling of Self-Adaptive Software Architectures

International audienceA common approach for engineering self-adaptive software systems is to use Feedback Control Loops (FCLs). Advances have led to more explicit and safer design of some control architectures, however, there is a need for more integrated and systematic approaches that support end-to-end integration of FCLs into software systems. In this paper, we propose a tooled approach that enables researchers and engineers to design and integrate adaptation mechanisms into software systems through FCLs. It consists of a domain-specific modeling language that raises the level of abstraction on which FCLs are defined, making them amenable to automated analysis and implementation code synthesis. The language supports composition, distribution and reflection, thereby enabling coordination and composition of multiple distributed FCLs. Its use is facilitated by a modeling environment, ACTRESS, that provides support for modeling, verification and complete code generation. We report on its application to a concrete adaptation case study and also discuss resulting properties

Utilization of temperature kinetics as a method to predict treatment intensity and corresponding treated wood quality : durability and mechanical properties of thermally modified wood

Wood heat treatment is an attractive alternative to improve decay resistance of wood species with low natural durability. However, this improvement of durability is realized at the expense of the mechanical resistance. Decay resistance and mechanical properties are strongly correlated to thermal degradation of wood cells wall components. Mass loss resulting from this degradation is a good indicator of treatment intensity and final treated wood properties. However, the introduction of a fast and accurate system for measuring this mass loss on an industrial scale is very difficult. Nowadays, many studies are conducted on the determination of control parameters which could be correlated with the treatment conditions and final heat treated wood quality such as decay resistance. The aim of this study is to investigate the relations between kinetics of temperature used during thermal treatment process representing heat treatment intensity, mass losses due to thermal degradation and conferred properties to heat treated wood. It might appear that relative area of treatment temperature curves is a good indicator of treatment intensity. Heat treatment with different treatment conditions (temperature-time) have been performed under vacuum, on four wood species (one hardwood and three softwoods) in order to obtain thermal degradation mass loses of 8, 10 and 12%. For each experiment, relative areas corresponding to temperature kinetics, mass loss, decay resistance and mechanical properties have been determined. Results highlight the statement that the temperature curves’ area constitutes a good indicator in the prediction of needed treatment intensity, to obtain required wood durability and mechanical properties such as bending resistance and Brinell hardness.LERMaB is supported by the French National Research Agency through the Laboratory of Excellence ARBRE (ANR-12- LABXARBRE-01), the authors gratefully acknowledge this ai

Index of efficiency for strength-grading machines for solid wood

The settings of strength-grading machine for structural pieces of wood are checked according to the EN 14081 standard. However, different machines have different performances depending on the accuracy of the estimation of the board’s properties, and there is no easy way to compare the efficiency of these machines especially if the machine does not use the same sampling. In this paper, we introduce an index called index of efficiency for grading machines. This parameter is in the range of 0–100% and allows to compare performances of different machines for a given set of grades. The computation of this index is based on the cost matrix method of the EN 14081 and requires to have the size matrix of a setting to be computed