scholarly journals Major Axis Cross-sectional Diameter at End Ventricular Systole

2020 ◽  
Author(s):  
Keyword(s):  
Major Axis ◽  
Cross Sectional ◽  
Ventricular Systole

scholarly journals Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

2014 ◽  
Author(s):  
Luis P Lamas ◽  
Russell P Main ◽  
John R. Hutchinson
Keyword(s):  
Body Mass ◽  
Functional Anatomy ◽  
Major Axis ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Positive Allometry ◽  
Dromaius Novaehollandiae ◽  
Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

scholarly journals Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

2014 ◽  
Author(s):  
Luis P Lamas ◽  
Russell P Main ◽  
John R. Hutchinson
Keyword(s):  
Body Mass ◽  
Functional Anatomy ◽  
Major Axis ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Positive Allometry ◽  
Dromaius Novaehollandiae ◽  
Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

scholarly journals Optimization of Geometric Parameters of Thermal Insulation of Pre-Insulated Double Pipes

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1012 ◽  
Author(s):  
Dorota Krawczyk ◽  
Tomasz Teleszewski
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Cross Section ◽  
Thermal Insulation ◽  
Major Axis ◽  
Heat Losses ◽  
Sectional Area ◽  
Cross Sectional ◽  
Elliptical Shape ◽  
Half Axis

This paper presents the analysis of the heat conduction of pre-insulated double ducts and the optimization of the shape of thermal insulation by applying an elliptical shape. The shape of the cross-section of the thermal insulation is significantly affected by the thermal efficiency of double pre-insulated networks. The thickness of the insulation from the external side of the supply and return pipes affects the heat losses of the double pre-insulated pipes, while the distance between the supply and return pipes influences the heat flux exchanged between these ducts. An assumed elliptical shape with a ratio of the major axis to the minor half axis of an ellipse equaling 1.93 was compared to thermal circular insulation with the same cross-sectional area. All calculations were made using the boundary element method (BEM) using a proprietary computer program written in Fortran as part of the VIPSKILLS project.

scholarly journals Measurement of needle susceptibility artifacts in magnetic resonance images

2015 ◽  
Vol 1 (1) ◽  
pp. 198-200
Author(s):  
Sebastian Schmitt ◽  
Katharina Skopnik ◽  
Heinrich Martin Overhoff
Keyword(s):  
Major Axis ◽  
Azimuth Angle ◽  
Magnetic Resonance Images ◽  
Semi Major Axis ◽  
Cross Sectional ◽  
Susceptibility Artifacts ◽  
Mr Guidance ◽  
The Cross ◽  
Sectional Shape ◽  
Angle Interval

AbstractThe success of minimally invasive procedures under MR-guidance can be increased by the knowledge of the current needle pose. We hypothesize that a one-toone mapping exists between the needle orientation with respect to the static magnetic field and the cross-sectional shape of the needle’s susceptibility artifact. For this purpose, we derived a mathematical model, which describes the cross sectional geometry of the needle artifact. It is approximated by two ellipses. Certain parameters of these ellipses can be utilized for mapping the geometry of the needle artifact onto the needle orientation. The relation between the two ellipse parameters α (inclination of the semi-major axis) and b (length of the semi-minor axis) and the needle’s azimuth angle can be approximated by linear regression in a certain angle interval. A combination of these two ellipse parameters is suitable for estimating the needle’s azimuth angle within a range between 0° and 60°.

Fatigue Tests on Specimens Containing Skew Holes

1976 ◽  
Vol 18 (6) ◽  
pp. 287-291 ◽  
Author(s):  
I. Ficenec ◽  
G. Craggs ◽  
B. N. Cole
Keyword(s):  
Fatigue Life ◽  
Endurance Limit ◽  
Fatigue Crack Initiation ◽  
Major Axis ◽  
Fatigue Tests ◽  
Minor Axis ◽  
Skew Angle ◽  
Cross Sectional ◽  
Skew Angles ◽  
Fatigue Endurance

The fatigue life of uniaxial fatigue specimens containing a skew hole is investigated. Contrary to expectation, fatigue life and fatigue endurance limit show no discernible change for vertical skew angles up to 45 when stress is calculated using the gross cross-sectional area. The point of fatigue crack initiation moves from the tip of the minor axis of the ellipse towards the tip of the major axis as skew angle increases.

Morphometry of the Basal Plate Superficial Uteroplacental Vasculature in Normal Midtrimester and at Term

2005 ◽  
Vol 8 (6) ◽  
pp. 639-646 ◽  
Author(s):  
Carolyn M. Salafia ◽  
John C. Pezzullo ◽  
Adrian K. Charles ◽  
Linda M. Ernst ◽  
Elizabeth M. Maas ◽  
...  
Keyword(s):  
New York ◽  
Cross Sections ◽  
Plate Thickness ◽  
Major Axis ◽  
Normal Pregnancy ◽  
Basal Plate ◽  
Cross Sectional ◽  
Clinically Normal ◽  
Arterial Structure ◽  
Path Lengths

Uteroplacental (UP) vascular arterial pathology has been associated with pregnancy complications. UP arterial structure has been characterized in placental bed biopsies, at the decidual-myometrial junction. Basal plate UP arteries, which are delivered with the placenta and thus routinely available, are not well characterized. We compared basal plate UP arterial segment morphometry in cases of elective termination of a clinically normal pregnancy at 11 to 24 weeks and of term birth. This study was done in a community-based obstetric service in New York City. UP arteries were identified in placentas of 20 midtrimester (MT) cases and 17 term (TERM) cases. We measured 336 UP artery cross-sections from 46 TERM and 290 MT cases. The basal plate UP artery path length was calculated as the distance between (x,y) coordinates of estimated centers of lumen cross-sections. Basal plate thickness near UP arteries, UP artery cross-sectional areas, vascular luminal eccentricity, and radial standard deviation were directly measured off digital images. Nonparametric and parametric methods compared groups, with P < 0.05 considered statistically significant. In TERM cases, the basal plate thickness near UP arteries was 1.8-fold thinner ( P = 0.002) and mean basal plate path lengths were 2.13-fold shorter ( P < 0.0001) than in MT cases. Mean TERM UP artery cross-sectional area was 3.15-fold larger, the major axis was 1.95-fold larger, and the minor axis was 1.75-fold larger than in MT arteries ( P = 0.001 to 0.008). Our data demonstrate that basal plate UP arteries (delivered with the placenta) are less tortuous, with shorter path lengths and larger areas as gestation advances. Normative morphometric data may allow improved diagnostics of placentas from complicated pregnancies.

Formability Enhancement in Titanium Tube-Flaring by Manipulating the Deformation Path

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Chetan P. Nikhare ◽  
Yannis P. Korkolis ◽  
Brad L. Kinsey
Keyword(s):  
Major Axis ◽  
Sectional Area ◽  
Deformation Path ◽  
Cross Sectional ◽  
Simple Process ◽  
Step Process ◽  
Tube Flaring ◽  
Titanium Tube ◽  
One Step ◽  
Punch Geometry

The tube flaring process has been traditionally used to expand one end of a tube without changing its cross-sectional area. This simple process typically forms the product using a single punch. To delay failure and enhance formability, a two-step flaring process can be used. For example, if a significant elliptical flared shape is attempted in a one-step process, a necking/tearing failure would occur on the major axis of the ellipse. However, if a two-step process, starting with a mildly elliptical punch and followed by the final, sharply elliptical punch is used instead, the desired elliptical shape can be achieved. In this paper, the effects of the punch geometry of the first step on the deformation paths are numerically analyzed. By manipulating the deformation path, failure can be delayed so that higher formability is achieved. The numerical model is validated by comparison with experimental results.

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