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Use of non-destructive test methods on Irish hardwood standing trees and small-diameter round timber for prediction of mechanical properties / Daniel F. Llana in Annals of Forest Science, vol 77 n° 3 (September 2020)
Titre : Use of non-destructive test methods on Irish hardwood standing trees and small-diameter round timber for prediction of mechanical properties Type de document : Article/Communication Auteurs : Daniel F. Llana, Auteur ; Ian Short, Auteur ; Annette M. Harte, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Acer pseudoplatanus
[Termes IGN] acoustique
[Termes IGN] Betula pendula
[Termes IGN] betula pubescens
[Termes IGN] bois sur pied
[Termes IGN] densité du bois
[Termes IGN] diamètre des arbres
[Termes IGN] éclaircie (sylviculture)
[Termes IGN] élagage (sylviculture)
[Termes IGN] élasticité
[Termes IGN] feuillu
[Termes IGN] Fraxinus (genre)
[Termes IGN] Fraxinus excelsior
[Termes IGN] Irlande
[Termes IGN] modèle de simulation
[Termes IGN] résonance
[Termes IGN] vent
[Vedettes matières IGN] SylvicultureRésumé : (auteur) Key message: Mechanical properties of small-diameter round timber from hardwood thinnings of common alder ( Alnus glutinosa (L.) Gaertn.), European ash ( Fraxinus excelsior L.), European birch ( Betula pendula Roth. and Betula pubescens Ehrh.), and sycamore ( Acer pseudoplatanus L.) can be evaluated by non-destructive testing on either standing trees or green logs without wood density determination. Velocity differences between acoustic and resonance methods are influenced by tree species and age. Tree diameter improves the estimation of bending strength but not of stiffness.
Context: There is a need for a reliable, fast, and inexpensive evaluation method to better sort hardwood thinnings according to mechanical properties for use in potential added-value applications.
Aims: The estimation by non-destructive testing of mechanical properties of round small-diameter timber of four hardwood species (common alder, European ash, European birch, and sycamore).
Methods: Acoustic velocity was measured in 38 standing trees and resonance velocity was recorded in green logs from these trees. The logs were then dried and tested in bending. Estimation models to predict mechanical properties from non-destructive testing measurements were developed.
Results: Large differences between velocities from acoustic and resonance techniques were found. Models based on both non-destructive testing velocities together with a species factor are well correlated with bending modulus of elasticity while models including tree diameter are moderately well correlated with bending strength. Inclusion of density in the models does not improve the estimation.
Conclusion: Models based on acoustic measurements on standing trees or resonance on green logs together with tree species and diameter provide reliable estimates of mechanical properties of round timber from hardwood thinnings. This methodology can be easily used for pre-sorting material in the forest.Numéro de notice : A2020-403 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-020-00957-x Date de publication en ligne : 17/06/2020 En ligne : https://doi.org/10.1007/s13595-020-00957-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95453
in Annals of Forest Science > vol 77 n° 3 (September 2020)[article]
Titre : Variations in the accuracy of gravity recovery due to ground track variability: GRACE, CHAMP, and GOCE Type de document : Article/Communication Auteurs : J. Klokocnik, Auteur ; C.A. Wagner, Auteur ; J. Kostelecky, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 917 - 927 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] GOCE
[Termes IGN] GRACE
[Termes IGN] orbite
[Termes IGN] poursuite de satellite
[Termes IGN] précision des mesures
[Termes IGN] résonanceRésumé : (Auteur) Following an earlier recognition of degraded monthly geopotential recovery from GRACE (Gravity Recovery And Climate Experiment) due to prolonged passage through a short repeat (low order resonant) orbit, we extend these insights also to CHAMP (CHAllenging Minisatellite Payload) and GOCE (Gravity field and steady state Ocean Circulation Explorer). We show wide track-density variations over time for these orbits in both latitude and longitude, and estimate that geopotential recovery will be as widely affected as well within all these regimes, with lesser track density leading to poorer recoveries. We then use recent models of atmospheric density to estimate the future orbit of GRACE and warn of degraded performance as other low order resonances are encountered in GRACE’s free fall. Finally implications for the GOCE orbit are discussed. Copyright Springer Numéro de notice : A2008-474 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0222-0 En ligne : https://doi.org/10.1007/s00190-008-0222-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29543
in Journal of geodesy > vol 82 n° 12 (December 2008) . - pp 917 - 927[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08111 RAB Revue Centre de documentation En réserve L003 Disponible 266-08112 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : Determination of characteristic site period and preliminary ground response analysis according to resonance by using GIS Type de document : Article/Communication Auteurs : M. Tun, Auteur ; Ugur Avdan, Auteur ; M. Altan, Auteur Année de publication : 2004 Article en page(s) : pp 31 - 36 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] bâtiment
[Termes IGN] milieu urbain
[Termes IGN] résonance
[Termes IGN] risque naturel
[Termes IGN] séisme
[Termes IGN] système d'information géographique
[Termes IGN] Turquie
[Termes IGN] vibrationRésumé : (Auteur) Ground response analyses are mostly used for the development of design response spectra in the modern earthquake engineering. After 1999 Marmara Earthquake, the damages were mostly related with unavailable soil conditions and this unavailability were analysed according to liquefaction analysis. In this study, granular soil which the Eskisehir urban area is located has been studied according to vibration period. Eskisehir is the city, which would be influenced negatively by the earthquake due to unavailable soil conditions and uncontrolled constructions. Five different districts of the Eskisehir municipality were included in this studied area. Characteristic site period (Ts), which is defined as the period of vibration corresponding to the fundamental frequency has been obtained for each 32 test points. GIS which is a powerful tool and technique for especially earth science, has been used for the preparation of characteristic site period map (Tf) of the studied area. After that, the number of story of each building has been determined by in-situ studies in the studied districts. Numéro de notice : A2004-405 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26932
in GIS Geo-Informations-Systeme > vol 2004 n° 9 (September 2004) . - pp 31 - 36[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 058-04091 RAB Revue Centre de documentation En réserve L003 Disponible Satellite orbit integration based on canonical transformations with special regard to the resonance and coupling effects / C. Cui (1997)
Titre : Satellite orbit integration based on canonical transformations with special regard to the resonance and coupling effects Type de document : Monographie Auteurs : C. Cui, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - A Sous-collection : Theoretische Geodäsie num. 112 Importance : 128 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-8193-2 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] modèle de géopotentiel
[Termes IGN] orbitographie
[Termes IGN] résonance
[Termes IGN] transformation canoniqueRésumé : (Auteur) Presented are the concept and the methods to get a complete analytical solution of the system of equations describing the motion of satellites under the action of a set of body and dissipative forces with consideration of coupling and resonance effects. A solution for the perturbations due to the Earth's direct geogravitation, due to the luni-solar gravitation, due to earth tide effects as well as due to the air drag and the normal solar radiation pressure is given including the interaction of orbital perturbations due to the different perturbation effects as well as resonance effects up to the second order. The equations of motion are formulated as a canonical system of equations including dissipation force terms by using the Hill-variables. An integrable Hamiltonian of such a system has been given in a quite general form as a guidance to select suitable canonical transformations and to solve the transformed system of equations. Resonance terms of the Hamiltonian are classified into two categories: normal (medium) resonance terms and strong ones. A successive infinitesimal Lie-transformation scheme has been developed in a general form to remove all periodic terms leading either to non-resonance effects or to medium resonance effects from the Hamiltonian.
This scheme has been applied to the system of equations of motion of the satellites involving also the action of non-gravitational forces. By this transformation the non-gravitational force terms are transformed too. In such a way a transformed system of equations (transformed Hamiltonian and transformed non-gravitational force terms) has been obtained. This transformed system of equations consists of a solvable major part and a minor part including both the strong resonance terms of the Hamiltonian together with the dissipation terms. The transformed system of equations has been solved by a linearisation approach usually called the Encke method. This method provides a regular solution for all orbital configurations with non-zero inclinations, among them in particular also orbits with the critical inclination, terrestrial repeating (cyclic) orbits and the polar orbits. All these kinds of orbit are of major importance for Earth observation satellites, but until now, they have only been treated insufficiently by the various existing forms of analytical solutions.Numéro de notice : 28248 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63594 Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 28248-01 21.10 Livre Centre de documentation Technologies spatiales Disponible 28248-02 21.10 Livre Centre de documentation Technologies spatiales Disponible Untersuchungen zu Erddeformationsmodellen für die Auswertung von geodätischen VLBI-Messungen / Rüdiger Haas (1996)
Titre : Untersuchungen zu Erddeformationsmodellen für die Auswertung von geodätischen VLBI-Messungen Titre original : [Recherches sur les modèles de déformation de la terre pour l'utilisation des mesures géodésiques d'interférométrie de très longue base] Type de document : Thèse/HDR Auteurs : Rüdiger Haas, Auteur Editeur : Francfort sur le Main : Institut für Angewandte Geodäsie Année de publication : 1996 Collection : DGK - C Sous-collection : Dissertationen num. 466 Importance : 103 p. Format : 21 x 30 cm Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données ITGB
[Termes IGN] interférométrie à très grande base
[Termes IGN] marée terrestre
[Termes IGN] résonance
[Termes IGN] rotation de la Terre
[Termes IGN] surcharge atmosphérique
[Termes IGN] surcharge océaniqueIndex. décimale : 30.63 Télémétrie laser sur satellite, Télémétrie laser sur lune, VLBI Résumé : (Auteur) Within the last 20 years geodetic Very Long Baseline Interferometry [VLBI] has been developed as an important technique for geodesy and geophysics. The primary purpose of geodetic VLBI is the establishment of terrestrial and celestial reference frames, measurement of present day tectonic motion and monitoring of Earth rotation.
The accuracy in modeling the theoretical observations for the analysis of space geodetic measurements should ideally be higher than the instrumental precision. Latter is for today's VLBI-system in the millimeter range while the accuracy of modeling is in the centimeter range.
For this reason international efforts endeavor to raise the accuracy of modeling to the millimeter level. As part of this effort this thesis investigates the modeling of Earth deformation effects for the analysis of geodetic VLBI observations. Existing theoretical models for Earth tides, ocean loading and atmospheric loading and their actual application in the analysis of VLBI data are considered.
In a first step worst case simulations are computed in order to evaluate the magnitude of the effects when neglecting them in the analysis.
Then parameters of the Earth deformation models are estimated from VLBI data to test the sensitivity of the VLBI observations to these neglections. In the results the theoretically predicted resonance of the Earth tides is clearly visible. However, the empirical resonance period is significantly different from the theoretical one with a tendency towards an independently inferred value from gravimetry. The estimates for ocean loading show a tendency towards the values of a newly developed loading model. Estimates for atmospheric loading show good agreement with theoretical values. Based upon these considerations recommendations for the treatment of Earth deformation effects in the analysis of space geodetic observations are developed.
As a consequence the VLBI analysis software is extended following these recommendations. The results of these extensions are tested in the analysis of VLBI observations in three different VLBI networks. Results for baseline lengths and Earth rotation parameters are compared with the results that are achieved using the standard analysis software. The comparisons show, that short time and long time repeatability of baseline length measurements improves with the use of the extended analysis software. The accuracy of Earth rotation parameters can be improved, too. The use of the extended software removes diurnal and sub diurnal parts from high frequency Earth rotation parameters, which have been misinterpreted as Earth rotation variations.Numéro de notice : 27066 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=56315 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 27066-01 30.63 Livre Centre de documentation Géodésie Disponible PermalinkPermalinkPermalinkPermalinkPermalinkPermalink
