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Shakti Chauhan - One of the best experts on this subject based on the ideXlab platform.
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Assessment of variability in morphological and wood quality traits in Melia dubia Cav. for selection of superior trees
Journal of the Indian Academy of Wood Science, 2014Co-Authors: Shakti Chauhan, A. N. Arun KumarAbstract:Assessment of natural variability in morphological and important wood quality traits and selection of trees with superior or desired wood characteristics is a prerequisite for an effective tree improvement. Variability in morphological and wood quality traits was assessed in selected trees from a 9-year-old plantation of Melia dubia raised from material of unknown genetic source. A large variation was observed in vertical and lateral tree growth within the sampled trees. Wood quality traits namely heartwood proportion, basic density, stress wave Velocity, dynamic modulus of elasticity (DMoE) and volumetric shrinkage also exhibited a substantial variation between trees. Pilodyn penetration exhibited a strong negative correlation with wood basic density and DMoE. Acoustic Velocity in trees, wood basic density, and volumetric shrinkage did not exhibit any significant relationship with each other. Similarly, tree growth parameters were not related to either wood density or shrinkage. Acoustic Velocity measured in standing trees by transit-time method was in a close agreement with the Velocity measured in logs using resonance method. A large variability in the measured traits and absence of any significant relationship in morphological and wood quality traits imply that selection of trees with superior wood properties can be made for further propagation without compromising on tree growth. Pilodyn and Acoustic Velocity measurements in standing trees provided an opportunity to screen and select M . dubia trees with superior wood density and modulus of elasticity.
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wood quality in artificially inclined 1 year old trees of eucalyptus regnans differences in tension wood and opposite wood properties
Canadian Journal of Forest Research, 2011Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and Acoustic Velocity, basic density, longitudinal shrinkage, and volumetric shrinkage of both opposite wood and tension wood were assessed subsequently. Longitudinal growth strains were also estimated in the leaning stems by sawing along the length through the pith and measuring the bending of the two halves. The derived longitudinal growth strain, which varied from 708 to 2319 µe, was uncorrelated with stem and wood characteristics. Wood characteristics differed significantly between upper-side wood (predominantly tension wood) and lower-side wood (opposite wood). Tension wood was characterized by a higher Acoustic Velocity (high stiffness), basic density, and volumetric shrinkage compared with opposite wood. Tension wood also exhibited significant collapse and dimensional distortion such as twisting. Longitudinal shrinkage exhibited a signifi...
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wood quality in artificially inclined 1 year old trees of eucalyptus regnans differences in tension wood and opposite wood properties
Canadian Journal of Forest Research, 2011Co-Authors: Shakti Chauhan, J C F WalkerAbstract:This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and Acoustic Velocity, basic densi...
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Wood quality in artificially inclined 1-year-old trees of Eucalyptus regnans — differences in tension wood and opposite wood properties
Canadian Journal of Forest Research, 2011Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and Acoustic Velocity, basic density, longitudinal shrinkage, and volumetric shrinkage of both opposite wood and tension wood were assessed subsequently. Longitudinal growth strains were also estimated in the leaning stems by sawing along the length through the pith and measuring the bending of the two halves. The derived longitudinal growth strain, which varied from 708 to 2319 µe, was uncorrelated with stem and wood characteristics. Wood characteristics differed significantly between upper-side wood (predominantly tension wood) and lower-side wood (opposite wood). Tension wood was characterized by a higher Acoustic Velocity (high stiffness), basic density, and volumetric shrinkage compared with opposite wood. Tension wood also exhibited significant collapse and dimensional distortion such as twisting. Longitudinal shrinkage exhibited a signifi...
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variations in Acoustic Velocity and density with age and their interrelationships in radiata pine
Forest Ecology and Management, 2006Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:Abstract Acoustic Velocity by the Fakopp time of flight (ToF) tool was used to estimate outerwood stiffness of trees within stands and between stands of different age classes (ages 8, 16 and 25). The TOF Acoustic Velocity measured in the standing trees was generally higher than the Acoustic Velocity measured by the Hitman (resonance) tool on the associated logs. The difference between the two velocities tended to be greater in the older and large diameter trees. The large variability in Acoustic Velocity, or preferably V 2 , makes it an efficient wood quality variable for screening trees. Wood density variables did not exhibit any relationship with Acoustic Velocity or modulus of elasticity (MoE) within each age-class. The classic pseudo-relationship observed with pooled data from all stand ages is mainly due to a stand age-effect and so one should be cautious in relying on any significant association between density and MoE.
John C. F. Walker - One of the best experts on this subject based on the ideXlab platform.
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wood quality in artificially inclined 1 year old trees of eucalyptus regnans differences in tension wood and opposite wood properties
Canadian Journal of Forest Research, 2011Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and Acoustic Velocity, basic density, longitudinal shrinkage, and volumetric shrinkage of both opposite wood and tension wood were assessed subsequently. Longitudinal growth strains were also estimated in the leaning stems by sawing along the length through the pith and measuring the bending of the two halves. The derived longitudinal growth strain, which varied from 708 to 2319 µe, was uncorrelated with stem and wood characteristics. Wood characteristics differed significantly between upper-side wood (predominantly tension wood) and lower-side wood (opposite wood). Tension wood was characterized by a higher Acoustic Velocity (high stiffness), basic density, and volumetric shrinkage compared with opposite wood. Tension wood also exhibited significant collapse and dimensional distortion such as twisting. Longitudinal shrinkage exhibited a signifi...
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Wood quality in artificially inclined 1-year-old trees of Eucalyptus regnans — differences in tension wood and opposite wood properties
Canadian Journal of Forest Research, 2011Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and Acoustic Velocity, basic density, longitudinal shrinkage, and volumetric shrinkage of both opposite wood and tension wood were assessed subsequently. Longitudinal growth strains were also estimated in the leaning stems by sawing along the length through the pith and measuring the bending of the two halves. The derived longitudinal growth strain, which varied from 708 to 2319 µe, was uncorrelated with stem and wood characteristics. Wood characteristics differed significantly between upper-side wood (predominantly tension wood) and lower-side wood (opposite wood). Tension wood was characterized by a higher Acoustic Velocity (high stiffness), basic density, and volumetric shrinkage compared with opposite wood. Tension wood also exhibited significant collapse and dimensional distortion such as twisting. Longitudinal shrinkage exhibited a signifi...
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variations in Acoustic Velocity and density with age and their interrelationships in radiata pine
Forest Ecology and Management, 2006Co-Authors: Shakti Chauhan, John C. F. WalkerAbstract:Abstract Acoustic Velocity by the Fakopp time of flight (ToF) tool was used to estimate outerwood stiffness of trees within stands and between stands of different age classes (ages 8, 16 and 25). The TOF Acoustic Velocity measured in the standing trees was generally higher than the Acoustic Velocity measured by the Hitman (resonance) tool on the associated logs. The difference between the two velocities tended to be greater in the older and large diameter trees. The large variability in Acoustic Velocity, or preferably V 2 , makes it an efficient wood quality variable for screening trees. Wood density variables did not exhibit any relationship with Acoustic Velocity or modulus of elasticity (MoE) within each age-class. The classic pseudo-relationship observed with pooled data from all stand ages is mainly due to a stand age-effect and so one should be cautious in relying on any significant association between density and MoE.
Jianxin Wei - One of the best experts on this subject based on the ideXlab platform.
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experimental study of water saturation effect on Acoustic Velocity of sandstones
Journal of Natural Gas Science and Engineering, 2016Co-Authors: Jianxin WeiAbstract:Abstract This study investigated the effect of water saturation on P-wave and S-wave Velocity of gas–water saturated sandstones under atmospheric and high confining pressure. The measured samples were artificial sandstones of the same composition and shale-free. Different porosity was the dominating parameter that influenced the elastic property. Measured results were compared with Gassmann fluid substitution combined with three different mixed fluids effective bulk modulus models. The results demonstrated that with the decrease of porosity and permeability the gas–water mixed fluids were more likely to be inhomogeneous in the pores of sandstone. P-wave Velocity trend was gradually close to the Gassmann–Hill boundary and away from Gassmann–Wood boundary, and the Gassmann–Brie model with an adjustable e -coefficient was more practical to estimate P-wave Velocity of sandstone. S-wave Velocity decreased linearly with the increase of water saturation. With the increase of confining pressure, the overall change in Velocity induced by saturation was gradually reduced, and rock compacting may cause the Velocity–saturation trend become close to the low porosity case.
Lars Olsson - One of the best experts on this subject based on the ideXlab platform.
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estimating solid wood properties using pilodyn and Acoustic Velocity on standing trees of norway spruce
Annals of Forest Science, 2015Co-Authors: Zhi-qiang Chen, Bo Karlsson, Sven-olof Lundqvist, Maria Rosario Garcia Gil, Lars OlssonAbstract:Key message Strong genetic correlations were observed between Pilodyn measurement and wood density, and between Acoustic Velocity and MFA. Combination of Pilodyn penetration and Acoustic Velocity measurements from standing trees can provide reliable prediction of stiffness of Norway spruce for breeding selection.
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Estimating solid wood properties using Pilodyn and Acoustic Velocity on standing trees of Norway spruce
Annals of Forest Science, 2015Co-Authors: Zhi-qiang Chen, Bo Karlsson, Sven-olof Lundqvist, María Rosario García Gil, Lars OlssonAbstract:AbstractKey messageStrong genetic correlations were observed between Pilodyn measurement and wood density, and between Acoustic Velocity and MFA. Combination of Pilodyn penetration and Acoustic Velocity measurements from standing trees can provide reliable prediction of stiffness of Norway spruce for breeding selection.ContextTraditional methods for the estimation of solid wood quality traits of standing tree such as wood density, microfibril angle (MFA), and modulus of elasticity (MOE) are time-consuming and expensive, which render them unsuitable for rapidly screening a large number of trees in tree breeding programs.AimThis study aims to evaluate the suitability of using Pilodyn penetration and Acoustic Velocity (nondestructive evaluation) to assess wood density, MFA, and MOE for Norway spruce.MethodsPilodyn penetration and Hitman Acoustic Velocity, as well as wood density, MFA, and MOE using benchmark SilviScan were measured on 5618 standing trees of 524 open-pollinated families in two 21-year-old Norway spruce (Picea abies) progeny trials in southern Sweden.ResultsStrong genetic correlations were observed between Pilodyn measurement and wood density (rg = −0.96), and between Acoustic Velocity and MFA (rg = −0.94). Combination of Pilodyn penetration and Hitman Acoustic Velocity measurements (MOEAV2+Pilo\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\mathrm{MOE}}_{\left({\mathrm{AV}}^2+\mathrm{Pilo}\right)} $$\end{document}) obtained from standing trees showed a genetic correlation with benchmark MOE of 0.99. This combined MOEAV2+Pilo\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\mathrm{MOE}}_{\left({\mathrm{AV}}^2+\mathrm{Pilo}\right)} $$\end{document} had higher selection efficiency for benchmark MOE (92 %) compared to 58–60 % using Acoustic Velocity alone and 78 % using Pilodyn penetration alone.ConclusionCombination of Pilodyn penetration with Hitman Acoustic Velocity provided very high selection efficiency for the three most important quality traits for wood mechanical properties in Norway spruce.
Wolfgang Meier - One of the best experts on this subject based on the ideXlab platform.
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thermo Acoustic Velocity coupling in a swirl stabilized gas turbine model combustor
Combustion and Flame, 2014Co-Authors: Vincent Cauxbrisebois, Adam M Steinberg, Christoph M Arndt, Wolfgang MeierAbstract:Abstract Limit-cycle thermo-Acoustic Velocity coupling mechanisms are studied in a perfectly-premixed swirl-stabilized combustor using data from 10 kHz repetition-rate stereoscopic particle image velocimetry (S-PIV) and OH planar laser induced fluorescence (PLIF). Five cases over a range of thermal powers and equivalence ratios were investigated, each of which underwent different amplitude limit-cycle oscillations. Proper orthogonal decomposition (POD) of the Velocity data showed that each case contained a dynamic helical vortex core (HVC) that rotated around the combustor and greatly affected the flame behavior. Flow and flame statistics were compiled as a function of both the phase in the thermo-Acoustic cycle and a phase representing the azimuthal position of the HVC relative to the measurement plane. These data were used to determine the thermo-Acoustic energy transfer field at each HVC azimuthal angle, as described by the Rayleigh integral. It was found that periodic deformations of the HVC caused large-scale flame motions, resulting in regions of positive and negative energy transfer. The deformation of the HVC was linked to a swirl number wave that propagated from the burner nozzle. While the mechanism of thermo-Acoustic coupling was the same for all cases, the phase between heat release and pressure oscillations varied significantly. This phase relationship was determined by the interaction of the pressure field, swirl wave, HVC deformation, and flame response. It was shown that these can be described by the combination of a Helmholtz resonator and a convective disturbance.
