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Intra-Ring Wood Density and Dynamic Modulus of Elasticity Profiles for Black Spruce and Jack Pine from X-ray Densitometry and Ultrasonic Wave Velocity Measurement

Intra-Ring Wood Density and Dynamic Modulus of Elasticity Profiles for Black Spruce and Jack Pine from X-ray Densitometry and Ultrasonic Wave Velocity Measurement

* Correspondence: ahmed.koubaa@uqat.ca; Tel.: +01-819-761-0971 (ext. 2579) † This manuscript is part of an M.S. thesis by the first author, available online at depositum.uqat.ca . Received: 30 May 2019; Accepted: 4 July 2019; Published: 9 July 2019    Abstract: Currently, ultrasonic measurement is a widely used nondestructive approach to determine wood elastic properties, including the dynamic modulus of elasticity (DMOE). DMOE is determined based on wood density and ultrasonic wave velocity measurement. The use of wood average density to estimate DMOE introduces significant imprecision: Density varies due to intra-tree and intra-ring differences and differing silvicultural treatments. To ensure accurate DMOE assessment, we developed a prototype device to measure ultrasonic wave velocity with the same resolution as that provided by the X-ray densitometer for measuring wood density. A nondestructive method based on X-ray densitometry and the developed prototype was applied to determine radial and intra-ring wood DMOE profiles. This method provides accurate information on wood mechanical properties and their sources of variation. High-order polynomials were used to model intra-ring wood density and DMOE profiles in black spruce and jack pine wood. The transition from earlywood to latewood was defined as the inflection point. High and highly significant correlations were obtained between predicted and measured wood density and DMOE. An examination of the correlations between wood radial growth, density, and DMOE revealed close correlations between density and DMOE in rings, earlywood, and latewood
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Modelling the effects of wood cambial age on the effective modulus of elasticity of poplar laminated veneer lumber

Modelling the effects of wood cambial age on the effective modulus of elasticity of poplar laminated veneer lumber

thus the coefficient of variation (6.95 and 2.67%) is obviously lower than in the exper- imental results from (around 15% regardless of the group). The experimental ratio between the dynamic MOE of juvenile and mature wood is 0.876, which is higher than the model prediction (0.785). However, the results of Rahayu et al. (2014) present a higher coefficient of variation (Table 1) . The study’s ratio is included between 0.69 and 1.06 by considering both standard deviations of ju- venile and mature modulus of elasticity. Indeed, uncertainty of a ratio can be calculated from the standard deviation of each part of this ratio. Therefore the results obtained with the model are close or similar to those from Rahayu et al. (2014). However, several reasons could have induced different ratios. From the experimental point of view, there exist difficulties in distinguishing juvenile from mature wood in Rahayu et al. (2014). Indeed, groups were made by visual observation of false heartwood but false heartwood does not necessarily correspond exactly to juvenile wood. Furthermore, a part of the studied logs was quite young, with a first quartile equal to 13.25 years, which leads to a minor number of mature annual growth rings to obtain a reliable long term evolution of mature wood properties. From the modelling point of view, there is a lack of exper- imental input data for mature wood in the literature (Thibaut et al. 2015), entailing an assumption of steady parameters for extra dataset domain for raw material properties. By doing so, the MOE of mature wood is bounded in the model, and the dispersion of LVL composed of mature wood is very low in comparison with experimental measure- ments. Thus the MOE can be underestimated, especially for mature wood, leading to the higher ratio between the juvenile and mature wood MOE observed in the model.
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The modulus of elasticity of leda clay from field measurements

The modulus of elasticity of leda clay from field measurements

The modulus of elasticity of leda clay from field measurements Bozozuk, M. https://publications-cnrc.canada.ca/fra/droits L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

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Estimating in-situ material properties of a wood joist floor: Part 1 - Measurements of the real part of bending wavenumber and modulus of elasticity

Estimating in-situ material properties of a wood joist floor: Part 1 - Measurements of the real part of bending wavenumber and modulus of elasticity

4. Conclusions Measuring the phase change along a draw-away line and conducting a regression analysis to determine the real part of the wavenumber is a relatively simple task. Wavenumber measurements along draw-away lines parallel and perpendicular to the joists confirmed the highly orthotropic nature of a wood joist floor. Measurements suggest that the degree of orthotropy in the direction parallel to the joists could be partially determined by the complex interaction of the OSB floor sheathing between the joists. It is suggested that below the cut-on frequency of the first cross mode, the joists significantly affect the stiffness of the OSB floor sheathing parallel to the joists. Above the frequency of the first cross mode, the effect of the joists is significantly reduced and in the limit, as the bending wavelength becomes much smaller than the joist spacing, the wavenumber (and bending stiffness) approaches that of the OSB floor sheathing in isolation. Wavenumbers in the direction parallel to the joists also approached those measured on OSB floor sheathing in isolation.
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Interrelation of hardness, modulus of elasticity, and porosity in various gypsum systems

Interrelation of hardness, modulus of elasticity, and porosity in various gypsum systems

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur. Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

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Study of the radiation effects on attached paint films by dynamic modulus of elasticity measurements

Study of the radiation effects on attached paint films by dynamic modulus of elasticity measurements

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur. Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

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Constant Modulus Algorithms via Low-Rank Approximation

Constant Modulus Algorithms via Low-Rank Approximation

tr(Wc j c H j ) = |v j | 2 j = 1, ..., J, (13c) W < 0. (13d) V. C ONVEX M ODIFIED L INEARLY C ONSTRAINED CMA The CM cost function is insensitive to the phase of the signal carrier. Therefore, in the presence of an unknown phase rotation the resulting estimated signal will also be rotated. A phase-sensitive modification of the CM cost function, referred to as the MCM, was introduced in [6], aimed at enabling improved performance for high order QAM and carrier phase synchronization. To introduce the MCM cost function, let w R , w I and y R (t), y I (t) denote, respectively, the real and
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Neural network modeling of resilient modulus and permanent deformation of aggregate materials

Neural network modeling of resilient modulus and permanent deformation of aggregate materials

Introduction The Urban Roads group of the National Research Council Canada has recently developed a new characterization scheme for determining the mechanistic properties of unbound materials (Khogali and Hussein, 2004). The established technique, named the M r –PD test, goes beyond the conventional method of determining the resilient modulus (M r ) by concurrently measuring the percentage permanent deformation (%PD) that the material accumulates under dynamic loading. The two parameters obtained from the test define the full material response; thus making it an effective method for assessing the material’s potential performance under prevailing in-situ conditions. Obtaining the two parameters in the laboratory for a wide range of physical and loading conditions is an expensive and time-consuming undertaking. This paper presents an approach that circumvents the need for extensive M r –PD testing by combining the use of limited laboratory-generated data with analytical modeling to produce adequate size databases.
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Characterization of the unfolding of a weak focus and modulus of analytic classification

Characterization of the unfolding of a weak focus and modulus of analytic classification

Preface The thesis is part of a program that aims to study the holomorphic classica- tion of generic unfoldings of the simplest codimension-one singularities of ana- lytic dynamical systems, the latter being given by germs of diffeomorphisms (in which case we study classication under conjugacy) or germs of vector elds (in which case we can study either classication under orbital equivalence or under conjugacy). The moduli space for these singularities has been described by J. Ecalle, S. M. Voronin (cf. [14],[51]) and J. Martinet-J. P. Ramis (cf. [35],[36]). In spite of the ““simple”” shape of these germs, except for the case of the node of a planar vector eld, the moduli space is a huge functional space, while, on the other hand, the formal invariants are in nite number. This means that there is an innite number of analytic obstructions for the analytic equivalence of two germs, that cannot be seen at the formal level. The former idea of V. I. Arnold et al. is that the modulus associated with the singularity can be explained by rst, complexifying the underlying space and then, by unfolding the singularity. Thus, the singularity of the dynamical system comes from the coallescence in a generic unfolding of a nite number of hyperbolic singularities or special hyperbolic ““ob- jects”” (like a periodic orbit or a limit cycle). Each hyperbolic object has its own geometric local model, and the modulus measures the mismatch of these local
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Cell Elasticity Determines Macrophage Function

Cell Elasticity Determines Macrophage Function

Competing Interests: The authors have declared that no competing interests exist. * E-mail: npatel@bidmc.harvard.edu Introduction Macrophages, despite arising from a common monocyte- granulocyte lineage, perform a myriad of functions such as host defense from infection, control of inflammation, and repair of injury [1,2,3] in order to preserve organ homeostasis. This is well demonstrated in the lungs where alveolar macrophages are the first line of host defense and serve as critical activators of inflammation promoting recruitment of neutrophils and other immune cells during the early stages of pneumonia [4]. Later in the course of pneumonia, alveolar macrophages are critical for controlling inflammation, limiting collateral damage, and promot- ing resolution through phagocytosis of bacteria, apoptotic host cells, and debris [5,6]. While lower respiratory tract infections comprise the single largest burden of disease worldwide as assessed by disability adjusted life years (DALYS) [7], there remains limited understanding of how dynamic regulation of macrophage function is achieved to preserve lung function. Regulation of macrophage function is presently understood mainly in the context of ligation events and downstream signaling [2,3] and attempts at describing macrophage phenotype have largely focused on changes in gene expression [8]. In the lungs, where mechanics play a critical role in determining organ function [9], pneumonia is typically associated with large increases in local tissue rigidity and decreases in tissue stretch [10,11]. It is also well recognized that biologic modulators such as bacterial pathogen associated molecular patterns (PAMPs) or cytokines increase both lung tissue rigidity [12,13], and cell
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On the modeling of thin plates in nonlinear elasticity

On the modeling of thin plates in nonlinear elasticity

Keywords: Nonlinearly elastic plates, derivation of two-dimensional models, nonexistence for membranes under compression, Ogden materials, incompressible materials, formal asymptotic exp[r]

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On the convergence of incremental methods in finite elasticity

On the convergence of incremental methods in finite elasticity

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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Effectiveness of predictive models for estimating asphalt concrete complex modulus

Effectiveness of predictive models for estimating asphalt concrete complex modulus

The models presented in Table 1 have several limitations. The major drawback of these equations is associated with the use of classical statistical principles to extrapolate parameters outside the range of the tests performed. The majority of test results were generated within a temperature range of 5 to 40 o C. This resulted in unrealistically large and small predictive moduli for very cold and very hot conditions outside this range. Fonseca and Witczak observed that the majority of these predictive equations were based on the original bitumen properties, with the test temperature being the most important variable in the system. However, these predictive equations do not account for the hardening effects on binders, and consequently the AC properties associated with long-term aging.
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Elastic modulus of a colloidal suspension of rigid spheres at rest

Elastic modulus of a colloidal suspension of rigid spheres at rest

4. Conclusions We have obtained a new expression for the elastic shear modulus of a colloidal suspension modeled as a solid. This expression allows to estimate the elastic modulus of a yield stress suspension submitted to a load smaller than the yield stress. This result was obtained in the framework of an homogenization approach to the behavior of a colloidal suspension considered as a discrete solid medium. Even if this approach relies on assumptions rather different from those classically performed to obtain estimates for the overall properties of suspensions in the framework of statistical mechanics, it is worth noting that classical results can also be recovered. Thus, we have shown that our estimate coincides with the classical high-frequency modulus estimate when the actual configuration is taken as the reference. From our point of view, this result was recovered by modeling the suspension as a “liquid”, ie a suspension without a yield stress. In this situation, it is not possible to define an “undeformed” configuration and the actual configuration is taken as the reference. To our opinion, this similarity is a strong indication that both approaches are consistent one to the other.
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The strain rate and temperature dependence of Young's modulus of ice

The strain rate and temperature dependence of Young's modulus of ice

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at The strain rate and temperature dependence of Young's modulus of ice Traetteberg, A.; Gold, L. W.; Frederking, R. M. W. https://publications-cnrc.canada.ca/fra/droits

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3D printed structures for modeling the Young’s modulus of bamboo parenchyma

3D printed structures for modeling the Young’s modulus of bamboo parenchyma

4.2. Limitations and opportunities Aspects of the specific method used in this study limit the inter- pretation of the results. These limitations pertain to the structure of printed parenchyma models and stem from a variety of sources. Limitations associated primarily with imaging and image process- ing will be discussed first. The relative density range of the test specimens is limited and their absolute values exceed 0.3. It was initially planned to test lower densities, but the images, and, to a greater degree the generated STL files, had cell wall connectivity issues that required the images to be dilated to remove the holes at nodes of the cell walls. It should also be noted that the binary operation did not result in all cell walls being completely con- nected. There were rare instances in the cell wall where the grey value was considerably lower and thresholded as background. These instances were not corrected, as they may correspond to physical regions of the actual cell wall with much lower stiffness and poorer load transfer capability. In higher density structures, some of these areas may become solid cell wall, resulting in stiff- ness increases due to increased connectivity and higher density.
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Predicting the resilient modulus of unbound granular materials by neural networks

Predicting the resilient modulus of unbound granular materials by neural networks

ABSTRACT: The process of pavement design requires the provision of material properties. For mechanistic–empirical design methods, the resilient modulus represents the most suitable alternative for describing the behavior of aggregate materials commonly used in sub-base and base layers. However, the adoption of the resilient modulus has been slow due to the complicated nature of the laboratory test used to obtain the parameter and its cost. Attempts to correlate the resilient modulus to the widely used California Bearing Ratio and other empirical parameters in the past fall short of providing reasonably accurate estimates of the parameter. With the renewed interest in using the resilient modulus as advocated by the AASHTO 2002 Guide, a quick and inexpensive solution to providing accurate estimates of this parameter is needed. This paper presents the artificial neural network (ANN) technique as a promising method that can help designers have a good first-step estimation of the resilient modulus based on data accumulated over the years. The study highlights the use of the ANN technique, which utilizes simple parameters as input to predict the resilient modulus of unbound granular materials. Results of ANN simulations confirm the potential of the technique to predict the resilient modulus of compacted samples tested at various compaction densities, states of stress and moisture contents. Such a tool represents an attractive alternative to laboratory testing for small jurisdictions with limited budgets and personnel.
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Effect of Chain Polydispersity on the Elasticity of Disordered Polymer Networks

Effect of Chain Polydispersity on the Elasticity of Disordered Polymer Networks

looked through the lens of polymer theories that rest too heavily on the Gaussianity of the chains. To conclude our analysis, we also apply our theoretical expressions to two sets of data, which have been recently published. Both experiments have been carried out in the group of Gong. 21 , 30 The first system is a tetra-PEG hydrogel composed of monodisperse long chains that can be greatly swollen by using a combined approach of adding a molecular stent and applying a PEG dehydration method. 21 Because the system is monodisperse and the chains are quite long, we expect the theoretical expressions derived here to work well. Indeed, as shown in Figure 7 d, the resulting Young ’s modulus is a nonmonotonic function of the swelling ratio Q, de fined as the ratio between the volume at which the measurements are performed and the volume at which the sample was synthesized. The experimental data can be fitted with both the L-FJC and WLC expressions (see Appendix A ) because both models reproduce the data with high accuracy when fitted with the two free parameters introduced above (R 0 and ⟨n⟩). However, better results are obtained with the WLC model, which fits well when ⟨n⟩ is fixed to its experimentally estimated value, yielding a value R 0 = 7.2 nm, which is very close to the independently estimated value of 8.1 nm, 21 in agreement with what reported in Hoshino et al. 21
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Linearization of a coupled system of nonlinear elasticity and fluid

Linearization of a coupled system of nonlinear elasticity and fluid

determine the velocity of the fluid v (see Figure 1). One specific example of the above mentioned model is a 3D tube with elastic walls through which a fluid is flowing. From the physical point of view, this is a very important model with a lot of applications in mathematical biology, more precisely, the study of arterial diseases (the tube represents the artery, the elastic body is the wall of the artery and the fluid is the blood).

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Impregnation as a technique for measuring zero porosity modulus of porous materials

Impregnation as a technique for measuring zero porosity modulus of porous materials

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur. For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

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