scholarly journals Ontogenetic changes of geometrical and mechanical characteristics of the avian femur: a comparison between precocial and altricial birds

2019 ◽  
Vol 235 (5) ◽  
pp. 903-911
Author(s):  
Xinsen Wei ◽  
Zihui Zhang
Keyword(s):  
Mechanical Characteristics ◽  
Ontogenetic Changes ◽  
Altricial Birds

scholarly journals Femoral mechanical performance of precocial and altricial birds: a simulation study

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xinsen Wei ◽  
Zihui Zhang
Keyword(s):  
Mechanical Performance ◽  
Axial Loading ◽  
Columba Livia ◽  
Ontogenetic Changes ◽  
Micro Computed Tomography ◽  
Erect Posture ◽  
Element Analysis ◽  
Lower Strain ◽  
Altricial Birds ◽  
Radial Loading

AbstractBackgroundAs the major load-bearing structures, bones exhibit various properties related to mechanical performance to adapt to different locomotor intensities. The habits and ontogenetic changes of locomotion in animals can, thus, be explored by assessing skeletal mechanical performance.MethodsIn this study, we investigated the growing femoral mechanical performance in an ontogenetic series of Cabot’s Tragopans (Tragopan caboti) and Pigeons (Columba livia domestica). Micro-computed tomography-based finite element analysis was conducted to evaluate the stress, strain, and strain energy density (SED) of femora under axial and radial loading.ResultsFemora deflected medio-laterally and dorso-ventrally under axial and radial loading, respectively. Femora deformed and tensed more severely under radial loading than axial loading. In adult individuals, Cabot’s Tragopans had lower strain and SED than pigeons. During ontogeny, the strain and SED of pigeons decreased sharply, while Cabot’s Tragopans showed moderately change. The structural properties of hatchling pigeons are more robust than those of hatchling Cabot’s Tragopans.ConclusionsLimb postures have dominant effect on skeletal deformation. The erect posture is preferred by large mammals and birds to achieve a high safety factor of bones during locomotion. Adult Cabot’s Tragopans have stronger femora than pigeons, reflecting a better bone adaption to the terrestrial locomotion of the studied pheasant species. Changes in strain and SED during growth reflect the marked difference in locomotor ability between precocial and altricial hatchlings. The femora of hatchling Cabot’s Tragopans were built with better energy efficiency than deformation resistance, enabling optimized mechanical performance. In contrast, although weak in mechanical function at the time of hatching, pigeon femora were suggested to be established with a more mature structural design as a prerequisite for rapid growth. These results will be helpful for studies regarding developmental patterns of fossil avian species.

Mechanical characteristics of the EGJ after fundoplication compared to normal subjects and GERD patients

2001 ◽  
Vol 120 (5) ◽  
pp. A112-A112 ◽  
Author(s):  
J CURRY ◽  
G SHI ◽  
J PANDOLFINO ◽  
R JOEHL ◽  
J BRASSEUR ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Normal Subjects

The Influence of Cross Edge Effect on Mechanical Characteristics of Electrodynamic Damping Element with Double Hollow Rotor

2016 ◽  
Vol 11 (4) ◽  
pp. 441
Author(s):  
Marina Gumerova ◽  
Flur Ismagilov ◽  
Irek Khairullin ◽  
Viacheslav Vavilov ◽  
Oksana Yushkova ◽  
...  
Keyword(s):  
Edge Effect ◽  
Mechanical Characteristics

Obtaining and Characterisation of Starch-Based Edible Films Incorporating Honey, Propolis and Bee Bread

2019 ◽  
Vol 23 (2) ◽  
pp. 193-198
Author(s):  
Monica Mironescu ◽  
Laura Fratila ◽  
Alexandru Hupert ◽  
Ion Dan Mironescu
Keyword(s):  
Water Activity ◽  
Mechanical Characteristics ◽  
Edible Films ◽  
Ash Content ◽  
Colour Intensity ◽  
Sensorial Analysis ◽  
Physical Chemical ◽  
Control Film ◽  
Bee Bread

Abstract This research investigates the physical-chemical, sensorial and mechanical characteristics of starch-based edible films incorporating three types of bee hive products: honey, propolis and bee bread, in concentrations varying from 1% to 3%, reported to starch. The results indicates an increasing of films moisture, water activity, ash content and acidity, in the order: honey<propolis<bee bread, all values increasing with the increasing of hive products percentage into the control film; aw is remaining at very low values, under 0.4. Sensorial analysis indicated honey as the better suited for improving taste and flavour and bee bread for increasing colour intensity of the films; the sensorial characteristics are maintained during 30 days of films storage, in all cases. Compared with the control starch-based film (which is elastic, brittle and hard), the films containing 2% bee hive products are elasto-plastic and more resistant to penetration, the resistance increasing in the order: bee bread<propolis<honey.

Evaluating Micro-Structure, Hydration and Thermal Expansions of Cement Containing Nano-Silica

GIS Business ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Dr. Sarvesh PS Rajput
Keyword(s):  
Portland Cement ◽  
Mechanical Characteristics ◽  
Microstructural Properties ◽  
Nano Silica ◽  
Micro Structure ◽  
Microstructural Characteristics ◽  
Mechanical And Microstructural Properties

This study reported that the addition of nano-silica enhances the mechanical characteristics of concrete as its compressive, flexural and tensile split strengths are increased. As a comparison mixture to equate it along with nano-modified concrete, ordinary samples of Portland cement (OPC) have been utilized. Herein, upto 6.0 percent of OPC has been substituted by nanosilica. In fact, the introduction of nanosilica improves mechanical and microstructural characteristics of concrete by significantly (28 to 35%). The finding therefore, indicated that partly replacing OPC with up to 5 percent nanosilica increases the mechanical and microstructural properties cured up to ninety days as opposed to the standard OPC mix.

Sign in / Sign up

Export Citation Format

Share Document