Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 573-581 ◽  
Author(s):  
José Xavier ◽  
Stéphane Avril ◽  
Fabrice Pierron ◽  
José Morais
Keyword(s):  
Experimental Approach ◽  
Grid Method ◽  
Field Method ◽  
Single Test ◽  
Specimen Length ◽  
Clear Wood ◽  
Coefficients Of Variation ◽  
Virtual Field ◽  
Order Of Magnitude ◽  
Rectangular Specimen

Abstract Experimental results obtained from maritime pine (Pinus pinaster Ait.) wood are presented for the characterisation of all LR=(1,2) orthotropic stiffness parameters of clear wood specimens by a single test. The approach relies on application of the virtual field method (VFM) to a rectangular specimen loaded in the Iosipescu fixture. The displacement field over the gauge surface of the specimen is measured by the grid method. Two configurations are investigated: (1) with grain aligned along the specimen length (0° configuration) and (2) with grain at 45°. For the 0° configuration, only the parameters Q 11 and Q 66 are correctly identified, with coefficients of variation of the same order of magnitude as those obtained from reference tensile and shear tests. Better identification is obtained for the 45° configuration, for which only the parameter Q 12 exhibits large scatter. This improvement results from a more balanced influence of all stiffness parameters on the response of the 45° specimen. However, all stiffness parameters identified were systematically underestimated by approximately 30% in comparison to reference values. This deviation is due to the vertical spatial variation of the mechanical properties of wood within the stem. Literature data confirm this interpretation.

A Review of Path Planning Method for Mobile Robot

2014 ◽  
Vol 1030-1032 ◽  
pp. 1588-1591 ◽  
Author(s):  
Zong Sheng Wu ◽  
Wei Ping Fu
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Optimal Path ◽  
Grid Method ◽  
Field Method ◽  
Planning Method ◽  
Artificial Potential Field ◽  
Planning Methods ◽  
Basic Ideas ◽  
Artificial Potential Field Method

The ability of a mobile robot to plan its path is the key task in the field of robotics, which is to find a shortest, collision free, optimal path in the various scenes. In this paper, different existing path planning methods are presented, and classified as: geometric construction method, artificial intelligent path planning method, grid method, and artificial potential field method. This paper briefly introduces the basic ideas of the four methods and compares them. Some challenging topics are presented based on the reviewed papers.

scholarly journals Variability Associated with Testing Shelled Corn for Fumonisin

1998 ◽  
Vol 81 (6) ◽  
pp. 1162-1168 ◽  
Author(s):  
Thomas B Whitaker ◽  
Mary W Trucksess ◽  
Anders S Johansson ◽  
Francis G Geesbrecht ◽  
Winston M Hagler ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Sample Preparation ◽  
Coefficient Of Variation ◽  
Variance Component ◽  
Test Procedure ◽  
Functional Relationships ◽  
Similar Test ◽  
Coefficients Of Variation ◽  
Order Of Magnitude

Abstract Variances associated with sampling, sample preparation, and analytical steps of a test procedure that measures fumonisin in shelled corn were estimated. The variance associated with each step of the test procedure increases with fumonisin concentration. Functional relationships between variance and fumonisin concentration were estimated by regression analysis. For each variance component, functional relationships were independent of fumonisin type (total, B1, B2, and B3 fumonisins). At 2 ppm, coefficients of variation associated with sampling (1.1 kg sample), sample preparation (Romer mill and 25 g subsample), and analysis are 16.6,9.1, and 9.7%, respectively. The coefficient of variation associated with the total fumonisin test procedure was 45% and is about the same order of magnitude as that for measuring aflatoxin in shelled corn with a similar test procedure.

Electronic Somatic Cell Count—Chemical Method, DMSCC, and WMT Tests for Raw Milk

1976 ◽  
Vol 39 (12) ◽  
pp. 854-858 ◽  
Author(s):  
D. R. THOMPSON ◽  
V. S. PACKARD ◽  
R. E. GINN
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Confidence Intervals ◽  
Somatic Cell Count ◽  
Raw Milk ◽  
Field Method ◽  
Regression Equations ◽  
Somatic Cell Counts ◽  
Cell Counts ◽  
Coefficients Of Variation

The Direct Miscroscopic Somatic Cell Count — field method (DMSCC), Wisconsin Mastitis Test (WMT), and Electronic Somatic Cell Count (ESCC) were studied to determine variability and relationship to each other. The coefficients of variation computed at a DMSCC count near one million were 15.6% (DMSCC), 6.3% (WMT), and 4.2% (ESCC). Linear regression equations were determined for predicting DMSCC results by WMT and ESCC. The approximate width of the 95% confidence intervals for ESCC predicting DMSCC were ± 275,000 and for WMT predicting DMSCC were ± 600,000. The prediction of square root and log transformations of DMSCC by WMT exhibited narrower confidence intervals for low somatic cell counts, but wider intervals for high counts (greater than 1,000,000).

Feasibility of Multiple Simultaneous Enzyme Assays, for Diagnostic Purposes, with the GeMSAEC Fast Analyzer

1971 ◽  
Vol 17 (8) ◽  
pp. 715-720 ◽  
Author(s):  
Thomas O Tiffany ◽  
George F Johnson ◽  
Max E Chilcote
Keyword(s):  
Large Scale ◽  
Experimental Approach ◽  
Clinical Chemistry ◽  
Chemistry Laboratory ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Clinical Chemistry Laboratory ◽  
Analytical Variation ◽  
Instrumental Precision

Abstract The GeMSAEC fast analyzer provides the clinical chemistry laboratory with an analytical instrument that can be used to perform large numbers of kinetic enzyme analyses. Precise enzyme-rate analyses can be done routinely, on a large scale, and at a decreased cost per test. Improved precision in analyses of enzymes should provide more reliable data because analytical variation is lessened. We have asked how the fast analyzer might provide more useful diagnostic information to the clinician. We have selected the ratio of SGOT to SGPT activity in serum as an example, and examined instrumental precision. The coefficients of variation of the ratio, determined in the range of 50 and 140 Karmen units (which represents slightly elevated to clearly elevated values), are 4.8% and 2.2%, respectively. We examined the feasibility of measuring two or more enzyme activities simultaneously in one sample, to produce a diagnostic enzyme profile. Determination of SGOT, SGPT, and GLDH in parallel is presented as an example. In addition, we illustrate spectrophotometric linearity at 340 nm and discuss instrumental noise and an experimental approach to determining it by use of a premix experiment.

scholarly journals Identification of Materials Properties Using Displacement Field Measurement

2011 ◽  
Vol 482 ◽  
pp. 57-65 ◽  
Author(s):  
Marina Fazzini ◽  
Olivier Dalverny ◽  
Sébastien Mistou
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Model Updating ◽  
Virtual Work ◽  
Field Measurements ◽  
Element Model ◽  
Field Method ◽  
Element Analysis ◽  
Virtual Field ◽  
Constitutive Parameters

The aim of this work is to identify parameters driving constitutive equations of materials with displacement field measurements carried out by image stereo-correlation during an unidirectional tensile test. We evaluate two identification techniques. The first one is the virtual fields method which consists in writing the principle of virtual work with particular virtual fields. It is generally used in the case of linear elasticity and it requires a perfect knowledge of the model in terms of boundary condition since the virtual fields used must be kinematically admissible. This method allows to determine parameters by a direct and fast calculation, without iterations. The second method is the finite element model updating method. It consists in finding constitutive parameters that achieve the best match between finite element analysis quantities and their experimental counterparts. This method is more adaptable than the virtual field method but it needs to spend more calculation time.

The Study of Soccer Robot Path Planning Based on Grid-Based Potential Field Method Improvements

2010 ◽  
Vol 139-141 ◽  
pp. 1798-1802 ◽  
Author(s):  
Xiao Jun Zhao ◽  
Jia Bi ◽  
Meng Zhe Liu ◽  
Lei Chen
Keyword(s):  
Path Planning ◽  
Potential Field ◽  
Grid Method ◽  
Field Method ◽  
Robot Path Planning ◽  
Soccer Robot ◽  
Potential Field Method ◽  
Dynamic Potential ◽  
Grid Based ◽  
Robot Path

An improved dynamic Grid-based potential field method was proposed based on the consideration that the goal, robot and obstacles in robot soccer compete are all dynamic. We combined the advantages of potential field method and the grid method, set the grid method to represent the environment, and got dynamic potential function in the potential field method. We used dynamic potential function to form the inspire function of the search algorithm A* which is used for the search of adjacent nodes. The dynamic Grid-based potential field method meets the real-time planning requirements in the complex and dynamic environment. And it has received very good results in solving the local minima problem of the traditional potential field and improving the planning efficiency. It is better in security and reliability. Simulation results show that the method is feasible and effective in soccer robot path planning.

Trace element behaviour during interaction between basalt and crustal rocks at 0.5–0.8 GPa: an experimental approach

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Silvio Mollo ◽  
Valeria Misiti ◽  
Piergiorgio Scarlato
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Diffusion Coefficients ◽  
Experimental Approach ◽  
Contact Layer ◽  
Major And Trace Elements ◽  
Crustal Rocks ◽  
Basaltic Melt ◽  
Order Of Magnitude ◽  
Diffusive Processes

AbstractWe experimentally investigate the major and trace elements behavior during the interaction between two partially molten crustal rocks (meta-anorthosite and metapelite) and a basaltic melt at 0.5–0.8 GPa. Results show that a hybrid melt is formed at the basalt-crust contact, where plagioclase crystallizes. This contact layer is enriched in trace elements which are incompatible with plagioclase crystals. Under these conditions, the trace element diffusion coefficients are one order of magnitude larger than those expected. Moreover, the HFSE diffusivity in the hybrid melt is surprisingly higher than the REE one. Such a feature is related to the plagioclase crystallization that changes the trace elements liquid-liquid partitioning (i.e. diffusivity) over a transient equilibrium that will persist as long as the crystal growth proceeds.These experiments suggests that the behaviour of the trace elements is strongly dependent on the crystallization at the magma-crust interface. Diffusive processes like those investigated can be invoked to explain some unusual chemical features of contaminated magmatic suites.

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