Influence of Cartilaginous Matrix Accumulation on Viscoelastic Response of Chondrocyte/Agarose Constructs Under Dynamic Compressive and Shear Loading

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Shogo Miyata ◽  
Tetsuya Tateishi ◽  
Takashi Ushida
Keyword(s):  
Energy Dissipation ◽  
Biochemical Composition ◽  
Dynamic Compression ◽  
Three Dimensional ◽  
Shear Stiffness ◽  
Relative Energy ◽  
Shear Loading ◽  
Cartilage Defects ◽  
Sgag Content ◽  
Matrix Accumulation

A method has been developed to restore cartilage defects by culturing autologous chondrocytes to create a three dimensional tissue and then implanting the cultured tissue. In this kind of approach, it is important to characterize the dynamic mechanical behavior of the regenerated cartilaginous tissue, because these tissues need to bear various dynamic loadings in daily life. The objectives of this study were to evaluate in detail the dynamic viscoelastic responses of chondrocyte-seeded agarose gel cultures in compression and torsion (shear) and to determine the relationships between these mechanical responses and biochemical composition. The results showed that both the dynamic compressive and shear stiffness of the cultured constructs increased during culture. The relative energy dissipation in dynamic compression decreased, whereas that in dynamic shear increased during culture. Furthermore, correlation analyses showed that the sulfated glycosaminoglycan (sGAG) content of the cultured construct showed significant correlations with the dynamic modulus in both compression and shear situations. On the other hand, the loss tangent in dynamic compression, which represents the relative energy dissipation capability of the constructs, showed a low correlation with the sGAG content, whereas this capability in shear exhibited moderate correlation. In conclusion, we explored the dynamic viscoelasticity of the tissue-engineered cartilage in dynamic compression and shear, and determined correlations between viscoelasticity and biochemical composition.

scholarly journals Three-Dimensional Investigation of Hydraulic Properties of Vertical Drop in the Presence of Step and Grid Dissipators

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 895
Author(s):  
Rasoul Daneshfaraz ◽  
Ehsan Aminvash ◽  
Amir Ghaderi ◽  
Alban Kuriqi ◽  
John Abraham
Keyword(s):  
Energy Dissipation ◽  
Laboratory Data ◽  
Three Dimensional ◽  
Relative Energy ◽  
Relative Depth ◽  
Pool Depth ◽  
Drainage Channels ◽  
Simultaneous Use ◽  
Fully Coupled ◽  
Irrigation And Drainage Channels

In irrigation and drainage channels, vertical drops are generally used to transfer water from a higher elevation to a lower level. Downstream of these structures, measures are taken to prevent the destruction of the channel bed by the flow and reduce its destructive kinetic energy. In this study, the effect of use steps and grid dissipators on hydraulic characteristics regarding flow pattern, relative downstream depth, relative pool depth, and energy dissipation of a vertical drop was investigated by numerical simulation following the symmetry law. Two relative step heights and two grid dissipator cell sizes were used. The hydraulic model describes fully coupled three-dimensional flow with axial symmetry. For the simulation, critical depths ranging from 0.24 to 0.5 were considered. Values of low relative depth obtained from the numerical results are in satisfactory agreement with the laboratory data. The simultaneous use of step and grid dissipators increases the relative energy dissipation compared to a simple vertical drop and a vertical drop equipped with steps. By using the grid dissipators and the steps downstream of the vertical drop, the relative pool depth increases. Changing the pore size of the grid dissipators does not affect the relative depth of the pool. The simultaneous use of steps and grid dissipators reduces the downstream Froude number of the vertical drop from 3.83–5.20 to 1.46–2.00.

scholarly journals Flow Over Embankment Gabion Weirs in Free Flow Conditions

2021 ◽  
Author(s):  
Roya Biabani ◽  
Farzin Salmasi ◽  
Meysam Nouri ◽  
John Abraham
Keyword(s):  
Energy Dissipation ◽  
Three Dimensional ◽  
Relative Energy ◽  
Physical Models ◽  
Flow Conditions ◽  
Environmental Aspects ◽  
Discharge Coefficients ◽  
Filling Materials ◽  
Surface Profiles ◽  
Crest Length

Abstract Gabion weirs have been widely used in rivers restoration and diversion water projects because of their hydro-environmental aspects and eco-friendly features. In this study, a series of laboratory tests were performed to investigate the effects of side ramp slope, crest length, and porous media properties on the flow regimes, water-surface profiles, discharge coefficients, and energy dissipation in embankment gabion weirs with upstream and downstream slopes. 24 physical models of solid and gabion weirs with three different upstream/downstream slopes (90°, 45° and 26.5°) were created. For gabion weirs, three different filling materials were tested. To investigate the complexity of flow over the porous-fluid interface and through the porous material, three-dimensional (3D) numerical simulations were developed. The results show that decreasing upstream slopes, from 90º to 26.5º, leads to decreased discharge coefficients. However, in all cases, gabion weirs lead to greater discharge coefficients than those of similar solid weirs. For milder side slopes, discharge ratios passing through all faces of the gabion weirs decreased nonlinearly. Moreover, with increasing the inlet discharge, relative energy dissipation was reduced up to 45% in gabion weirs.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

RETARDATION EFFECTS IN COVARIANT THREE-DIMENSIONAL BOUND STATE WAVE FUNCTIONS

2005 ◽  
Vol 14 (06) ◽  
pp. 931-947 ◽  
Author(s):  
F. PILOTTO ◽  
M. DILLIG
Keyword(s):  
Bound States ◽  
Three Dimensional ◽  
Bound State ◽  
Relative Energy ◽  
Wave Functions ◽  
Three Dimensions ◽  
State Wave ◽  
Scalar Diquark ◽  
Bound State Wave Function ◽  
Retardation Effects

We investigate the influence of retardation effects on covariant 3-dimensional wave functions for bound hadrons. Within a quark-(scalar) diquark representation of a baryon, the four-dimensional Bethe–Salpeter equation is solved for a 1-rank separable kernel which simulates Coulombic attraction and confinement. We project the manifestly covariant bound state wave function into three dimensions upon integrating out the non-static energy dependence and compare it with solutions of three-dimensional quasi-potential equations obtained from different kinematical projections on the relative energy variable. We find that for long-range interactions, as characteristic in QCD, retardation effects in bound states are of crucial importance.

scholarly journals A Structural Grammar Approach for the Generative Design of Diagrid-Like Structures

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 90
Author(s):  
Francesco Cascone ◽  
Diana Faiella ◽  
Valentina Tomei ◽  
Elena Mele
Keyword(s):  
Minimum Weight ◽  
Three Dimensional ◽  
Tall Buildings ◽  
Shear Stiffness ◽  
Design Strategy ◽  
Design Criterion ◽  
Generative Design ◽  
Building Models ◽  
Local Strength ◽  
And Performance

An innovative generative design strategy, based on shape grammar, is proposed for the minimum-weight design of diagrid tall buildings. By considering the building as a three-dimensional vertical cantilever beam with a tubular section under horizontal load, it is evident that bending and shear stiffness demands vary along the width and elevation of the building. Further, while the structural design of tall buildings is usually governed by stiffness, the predominant design criterion for diagrids could be the local strength demand, especially for low slenderness values, thanks to the inherent rigidity of the triangular pattern. Starting from these considerations, in this paper, a generative design strategy is proposed, able to find diagrid patterns that accommodate the differentiated stiffness demand along width/elevation and satisfy the predominant design criterion, stiffness or strength. The design strategy is applied to tall building models characterised by different slenderness values. The comparison to diagrid patterns analysed in previous literature works in terms of structural weight and performance parameters highlights the effectiveness of the design strategy and the efficiency of the generated patterns.

scholarly journals NEW EVIDENCE OF DISCRETE SCALE INVARIANCE IN THE ENERGY DISSIPATION OF THREE-DIMENSIONAL TURBULENCE: CORRELATION APPROACH AND DIRECT SPECTRAL DETECTION

2003 ◽  
Vol 14 (04) ◽  
pp. 459-470 ◽  
Author(s):  
WEI-XING ZHOU ◽  
DIDIER SORNETTE ◽  
VLADILEN PISARENKO
Keyword(s):  
Energy Dissipation ◽  
Three Dimensional ◽  
Energy Dissipation Rate ◽  
Corrections To Scaling ◽  
Developed Turbulence ◽  
Pairwise Correlations ◽  
Spectral Detection ◽  
Simple Variant ◽  
High Reynolds ◽  
New Evidence

We extend the analysis of Ref. 16 showing statistically significant log-periodic corrections to scaling in the moments of the energy dissipation rate in experiments at high Reynolds number (≈ 2500) of three-dimensional fully developed turbulence. First, we develop a simple variant of the canonical averaging method using a rephasing scheme between different samples based on pairwise correlations that confirms Zhou and Sornette's previous results. The second analysis uses a simpler local spectral approach and then performs averages over many local spectra. This yields stronger evidence of the existence of underlying log-periodic undulations, with the detection of more than 20 harmonics of a fundamental logarithmic frequency f = 1.434 ± 0.007 corresponding to the preferred scaling ratio γ = 2.008 ± 0.006.

Three-Dimensional Analysis of Closed-Die Forging Processes: Part 1: Formulation

1989 ◽  
Vol 203 (1) ◽  
pp. 33-37 ◽  
Author(s):  
C F Lugora ◽  
A N Bramley
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Metal Flow ◽  
Three Dimensional ◽  
Total Rate ◽  
Die Forging ◽  
Closed Die Forging ◽  
Proposed Model ◽  
Optimum Velocity ◽  
Forging Load

In this series of papers, a theoretical model based on the upper bound elemental technique is presented for prediction of forging load and metal flow in three-dimensional closed-die forging processes. Three basic elements are introduced in order to partition a forging into simple elementary regions. An optimum velocity distribution within the forging is obtained by minimizing the total rate of energy dissipation using a simplex optimizing procedure. Applications of the proposed model are discussed in Part 2.

Study on Hydraulic Characteristics and Optimization of Siphon Channel with Two Inlets in Drydock

2014 ◽  
Vol 638-640 ◽  
pp. 1285-1292
Author(s):  
Peng Zhao ◽  
Yu Chuan Bai
Keyword(s):  
Energy Dissipation ◽  
Numerical Model ◽  
Kinetic Energy ◽  
Dissipation Rate ◽  
Three Dimensional ◽  
Flow State ◽  
Hydraulic Characteristics ◽  
Channel System ◽  
Guide Wall ◽  
Low Efficiency

Compared with the siphon channel with one inlet, the siphon channel with two inlets has some problems such as low efficiency of flooding. Combining with the model test of siphon channel with two inlets in a drydock, three-dimensional numerical model was built to study the hydraulic characteristics of siphon channel system. The reliability of numerical model was confirmed by comparing the calculated value and measured value of hump pressure and flooding rate. Results of turbulent kinetic energy and dissipation rate indicate that flow kinetic energy is mainly dissipated by the friction and its impacting the wall behind partition and the effect of energy dissipation pillars are not obvious. By comparing flow state in front of energy dissipation section and flooding rate between design scheme and modified scheme, it is suggested that the guide wall should be dismantled to ameliorate flow state.

Energy dissipation by whistler turbulence: Three-dimensional particle-in-cell simulations

2014 ◽  
Vol 21 (5) ◽  
pp. 052305 ◽  
Author(s):  
Ouliang Chang ◽  
S. Peter Gary ◽  
Joseph Wang
Keyword(s):  
Energy Dissipation ◽  
Three Dimensional ◽  
Particle In Cell
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