Models of the mechanical sensitivity and growth of otoliths in fish

2003 ◽  
Vol 13 (4-6) ◽  
pp. 189-203
Author(s):  
Alexander V. Kondrachuk
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Oscillator Model ◽  
Distributed Model ◽  
Mechanical Sensitivity ◽  
Otolith Growth ◽  
Altered Gravity ◽  
Gel Layer ◽  
Longitudinal Size ◽  
Spatially Distributed

It has been suggested that, in the fish, the change of otolith mass during development under altered gravity conditions [1,2,3,4,5,6,24,25,36,37] and the growth of otoliths in normal conditions [22,23,26], are determined by feedback between otolith dynamics and the processes that regulate otolith growth. The hypothesis originates from an oscillator model of the otolith [30] in which otolith mass is one of the parameters. However, the validity of this hypothesis is not obvious and has not been experimentally verified. We tested this hypothesis by comparing the oscillator model with a simplified spatially distributed model of the otolith. It was shown that in the case of a spatially distributed fixation of the otolith plate (otoconial layer) to the macular surface, the mechanical sensitivity of the otolith does not depend on the total otolith mass nor on its longitudinal size. It is determined by otolith thickness, the Young's modulus and viscosity of gel layer of the growing otolith. These parameters may change in order to maintain otolith sensitivity under conditions (such as growth or altered gravity) that change the dynamics of otolith movement.

Finite element modeling of the 3D otolith structure

2001 ◽  
Vol 11 (1) ◽  
pp. 13-32
Author(s):  
Alexander V. Kondrachuk
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Finite Size ◽  
Element Model ◽  
Spatial Inhomogeneity ◽  
Mechanical Parameters ◽  
Static Loads ◽  
Gel Layer ◽  
Endolymphatic Pressure

A 3D finite element model (FEM) of the mammalian utricular otolith corresponding to spatial structure, shape and size of the otolith from the guinea pig was developed. The otolithic membrane (OM) was considered as consisting of gel and otoconial layers. The macular surface was approximated as a plane. The deformation of the OM under static loads such as gravity and the change of endolymphatic pressure was analyzed using the FEM for different mechanical parameters of the OM and for different gravity vector orientations. The analytical dependence of OM displacements caused by the acceleration parallel to the macular plane was obtained. By comparison of the results of calculations with the known experimental data Young’s modulus of the gel layer was estimated to be of order of 10 N/m 2 . It was shown that static loads result in 3D local otolith displacements inhomogeneously distributed along the macular surface and across otolith thickness. Their distribution depends on the geometrical and mechanical parameters of the otolith components. The influences of the finite size of the OM, the Young’s modulus, Poisson’s ratio and thickness of the gel layer on the local displacements distribution of the OM were analyzed. The results of simulation suggest that: a) the Young’s modulus of the thin lowest part of the gel layer adjacent to the macular surface is much smaller than that of the rest of the OM; b) the structure of the border is designed to reduce the spatial inhomogeneity of the gel layer displacement; c) a change of the endolymphatic pressure may result in significant deformation of the OM.

Effect of Sample Materials on the AFM Tip-Based Dynamic Ploughing Process

2011 ◽  
Vol 314-316 ◽  
pp. 492-496
Author(s):  
Yong Da Yan ◽  
Wei Tao Liu ◽  
Zhen Jiang Hu ◽  
Xue Sen Zhao ◽  
Jiu Chun Yan
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Sample Surface ◽  
Machining Process ◽  
Oscillator Model ◽  
Tapping Mode ◽  
Tip Radius ◽  
Spring Constants

To study the effect of different sample materials on the nano dynamic ploughing process in the AFM tapping mode, the spring-oscillator model is employed to simulate the vibrating AFM tip to deform the sample surface. On the surface of different samples with the Young’s modulus of 0.2 GPa, 80 GPa and 180 Gpa, the interaction between the tip and the sample is simulated with different driven amplitudes, spring constants, tip radius and original tip-sample distances. These effects are studied. Results show that the sample with a smaller Young’s modulus is suitable for being used as the sample machined by the dynamic ploughing technique. When the Young’s modulus is greater than 80 GPa, the machine depth is so small that the machining process can not be controlled as we required.

scholarly journals Mapping Spatially Distributed Material Properties in Finite Element Models of Plant Tissue Using Computed Tomography

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Ryan Larson ◽  
Douglas D Cook
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Young’S Modulus ◽  
Material Properties ◽  
Young's Modulus ◽  
Spatial Mapping ◽  
Finite Element Models ◽  
Tissue Stiffness ◽  
Spatially Distributed ◽  
Tomography Data

AbstractPlant tissues are often heterogeneous. To accurately investigate these tissues, we will need methods to spatially map these tissue stiffness values onto finite element models. The purpose of this research is to develop a method for using specimen-specific computed tomography data to inform the spatial mapping of Young’s modulus values on finite element models. The spatial mapping of Young’s modulus was calculated and then used to predict the response of specimen tests. Results indicated that this method can be used to obtain spatial distributions of material properties, thus enabling finite element models that account for material heterogeneity.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

Degradation of Rocks, Through Cracking Caused by Differential Thermal Expansion, in Relation to Nuclear Waste Repositories

1981 ◽  
Vol 6 ◽  
Author(s):  
J.R. Mclaren ◽  
R.W. Davidge ◽  
I. Titchell ◽  
K. Sincock ◽  
A. Bromley
Keyword(s):  
Thermal Expansion ◽  
Grain Boundary ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Crack Density ◽  
Granitic Rocks ◽  
Multiphase Materials ◽  
Thermal Expansion Behaviour ◽  
Waste Repositories ◽  
Expansion Behaviour

ABSTRACTHeating to temperatures up to 500°C, gives a reduction in Young's modulus and increase in permeability of granitic rocks and it is likely that a major reason is grain boundary cracking. The cracking of grain boundary facets in polycrystalline multiphase materials showing anisotropic thermal expansion behaviour is controlled by several microstructural factors in addition to the intrinsic thermal and elastic properties. Of specific interest are the relative orientations of the two grains meeting at the facet, and the size of the facet; these factors thus introduce two statistical aspects to the problem and these are introduced to give quantitative data on crack density versus temperature. The theory is compared with experimental measurements of Young's modulus and permeability for various rocks as a function of temperature. There is good qualitative agreement, and the additional (mainly microstructural) data required for a quantitative comparison are defined.

Is it necessary to calculate Young’s modulus in AFM nanoindentation experiments regarding biological samples?

2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou
Keyword(s):  
Young’S Modulus ◽  
Biological Samples ◽  
Young's Modulus ◽  
Reference Sample ◽  
Nonlinear Behavior ◽  
Accurate Method ◽  
Accurate Solution ◽  
Hertz Model ◽  
Work Done

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.

Effect of Microcrystalline Cellulose from Banana Stem Fiber on Mechanical Properties and Crystallinity of PLA Composite Films

2011 ◽  
Vol 695 ◽  
pp. 170-173 ◽  
Author(s):  
Voravadee Suchaiya ◽  
Duangdao Aht-Ong
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Microcrystalline Cellulose ◽  
Young's Modulus ◽  
Agricultural Waste ◽  
Composite Films ◽  
Sem Image ◽  
Biocomposite Films ◽  
Twin Screw ◽  
Banana Stem

This work focused on the preparation of the biocomposite films of polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC) prepared from agricultural waste, banana stem fiber, and commercial microcrystalline cellulose, Avicel PH 101. Banana stem microcrystalline cellulose (BS MCC) was prepared by three steps, delignification, bleaching, and acid hydrolysis. PLA and two types of MCC were processed using twin screw extruder and fabricated into film by a compression molding. The mechanical and crystalline behaviors of the biocomopsite films were investigated as a function of type and amount of MCC. The tensile strength and Young’s modulus of PLA composites were increased when concentration of MCC increased. Particularly, banana stem (BS MCC) can enhance tensile strength and Young’s modulus of PLA composites than the commercial MCC (Avicel PH 101) because BS MCC had better dispersion in PLA matrix than Avicel PH 101. This result was confirmed by SEM image of fractured surface of PLA composites. In addition, XRD patterns of BS MCC/PLA composites exhibited higher crystalline peak than that of Avicel PH 101/PLA composites

scholarly journals Out-of-Plane Thermal Expansion Coefficient and Biaxial Young’s Modulus of Sputtered ITO Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 153
Author(s):  
Chuen-Lin Tien ◽  
Tsai-Wei Lin
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Young's Modulus ◽  
Heating Temperature ◽  
Glass Substrates ◽  
Ito Thin Films

This paper proposes a measuring apparatus and method for simultaneous determination of the thermal expansion coefficient and biaxial Young’s modulus of indium tin oxide (ITO) thin films. ITO thin films simultaneously coated on N-BK7 and S-TIM35 glass substrates were prepared by direct current (DC) magnetron sputtering deposition. The thermo-mechanical parameters of ITO thin films were investigated experimentally. Thermal stress in sputtered ITO films was evaluated by an improved Twyman–Green interferometer associated with wavelet transform at different temperatures. When the heating temperature increased from 30 °C to 100 °C, the tensile thermal stress of ITO thin films increased. The increase in substrate temperature led to the decrease of total residual stress deposited on two glass substrates. A linear relationship between the thermal stress and substrate heating temperature was found. The thermal expansion coefficient and biaxial Young’s modulus of the films were measured by the double substrate method. The results show that the out of plane thermal expansion coefficient and biaxial Young’s modulus of the ITO film were 5.81 × 10−6 °C−1 and 475 GPa.

Sign in / Sign up

Export Citation Format

Share Document