scholarly journals Minor Axis Cross-sectional Diameter

2020 ◽  
Author(s):  
Keyword(s):  
Minor Axis ◽  
Cross Sectional

Collapse of Thin-Walled Elliptical Tubes for High Values of Major-to-Minor Axis Ratio

1993 ◽  
Vol 115 (4A) ◽  
pp. 432-440 ◽  
Author(s):  
C. Ribreau ◽  
S. Naili ◽  
M. Bonis ◽  
A. Langlet
Keyword(s):  
Contact Pressure ◽  
Cross Section ◽  
External Pressure ◽  
Straight Line Segment ◽  
Minor Axis ◽  
Cross Sectional ◽  
Axis Ratio ◽  
Straight Line ◽  
Thin Walled ◽  
The Cross

The topic of this study concerns principally representative models of some elliptical thin-walled anatomic vessels and polymeric tubes under uniform negative transmural pressure p (internal pressure minus external pressure). The ellipse’s ellipticity ko, defined as the major-to-minor axis ratio, varies from 1 up to 10. As p decreases from zero, at first the cross-section becomes somewhat oval, then the opposite sides touch in one point at the first-contact pressure pc. If p is lowered beneath pc, the curvature of the cross-section at the point of contact decreases until it becomes zero at the osculation pressure or the first line-contact pressure p1. For p<p1, the contact occurs along a straight-line segment, the length of which increases as p decreases. The pressures pc and p1 are determined numerically for various values of the wall thickness of the tubes. The nature of contact is especially described. The solution of the related nonlinear, two-boundary-values problem is compared with previous experimental results which give the luminal cross-sectional area (from two tubes), and the area of the mid-cross-section (from a third tube).

Age-related changes in chest geometry during cardiopulmonary resuscitation

1987 ◽  
Vol 62 (6) ◽  
pp. 2212-2219 ◽  
Author(s):  
J. M. Dean ◽  
R. C. Koehler ◽  
C. L. Schleien ◽  
J. R. Michael ◽  
T. Chantarojanasiri ◽  
...  
Keyword(s):  
Cardiopulmonary Resuscitation ◽  
Cross Section ◽  
Circular Cross Section ◽  
Elliptic Cylinder ◽  
Minor Axis ◽  
Cross Sectional ◽  
Age Related ◽  
Chest Deformity ◽  
Age Related Changes ◽  
Intravascular Pressure

We studied alterations of chest geometry during conventional cardiopulmonary resuscitation in anesthetized immature swine. Pulsatile force was applied to the sternum in increments to determine the effects of increasing compression on chest geometry and intrathoracic vascular pressures. In 2-wk- and 1-mo-old piglets, permanent changes in chest shape developed due to incomplete recoil of the chest along the anteroposterior axis, and large intrathoracic vascular pressures were generated. In 3-mo-old animals, permanent chest deformity did not develop, and large intrathoracic vascular pressures were not produced. We propose a theoretical model of the chest as an elliptic cylinder. Pulsatile displacement along the minor axis of an ellipse produces a greater decrease in cross-sectional area than displacement of a circular cross section. As thoracic cross section became less circular due to deformity, greater changes in thoracic volume, and hence pressure, were produced. With extreme deformity at high force, pulsatile displacement became limited, diminishing pressure generation. We conclude that changes in chest geometry are important in producing intrathoracic intravascular pressure during conventional cardiopulmonary resuscitation in piglets.

Dynamic Detection and Analysis of Raw Silk’s Flatness

2011 ◽  
Vol 175-176 ◽  
pp. 385-388
Author(s):  
Xin Zhang ◽  
Yi Quan Xu ◽  
Kai Meng ◽  
Qing Guan Chen
Keyword(s):  
Cross Section ◽  
Axial Length ◽  
Minor Axis ◽  
Cross Sectional Area ◽  
Elliptical Cross Section ◽  
Sectional Area ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Photoelectric Sensor ◽  
Dynamic Detection

The shape of most raw silk’s cross-section can be regarded as ellipse approximately. Axial length of the raw silk’s cross-section was detected and recorded dynamically by photoelectric sensor combined with the software of LabVIEW. Two photoelectric sensors were located orthogonally to measure axial lengths of the ellipse. The major and minor values can be considered as the major and minor axis values of the raw silk’s elliptical cross-section respectively. Thereby, the flatness and the area of raw silk’s cross-section can be calculated according to the values of major and minor axes. In addition, the raw silk’s evenness was characterized based on the variation of the cross-sectional area.

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.

Geometric changes of the inferior vena cava in trauma patients subjected to volume resuscitation

Vascular ◽  
2014 ◽  
Vol 23 (5) ◽  
pp. 459-467 ◽  
Author(s):  
Samuel L Chen ◽  
Mayil S Krishnam ◽  
Thangavijayan Bosemani ◽  
Sumudu Dissayanake ◽  
Michael D Sgroi ◽  
...  
Keyword(s):  
Inferior Vena Cava ◽  
Renal Vein ◽  
Inferior Vena ◽  
Vena Cava ◽  
Major Axis ◽  
Minor Axis ◽  
Trauma Patients ◽  
Cross Sectional ◽  
Area And Perimeter ◽  
Left Anterior Oblique

ObjectiveDynamic changes in anatomic geometry of the inferior vena cava from changes in intravascular volume may cause passive stresses on inferior vena cava filters. In this study, we aim to quantify variability in inferior vena cava dimensions and anatomic orientation to determine how intravascular volume changes may impact complications of inferior vena cava filter placement, such as migration, tilting, perforation, and thrombosis.MethodsRetrospective computed tomography measurements of major axis, minor axis, and horizontal diameters of the inferior vena cava at 1 and 5 cm below the lowest renal vein in 58 adult trauma patients in pre-resuscitative (hypovolemic) and post-resuscitative (euvolemic) states were assessed in a blinded fashion by two independent readers. Inferior vena cava perimeter, area, and volume were calculated and correlated with caval orientation.ResultsMean volumes of the inferior vena cava segment on pre- and post-resuscitation scans were 9.0 cm3and 11.0 cm3, respectively, with mean percentage increase of 48.6% ( P < 0.001). At 1 cm and 5 cm below the lowest renal vein, the inferior vena cava expanded anisotropically, with the minor axis expanding by an average of 48.7% ( P < 0.001) and 30.0% ( P = 0.01), respectively, while the major axis changed by only 4.2% ( P = 0.11) and 6.6% ( P = 0.017), respectively. Cross-sectional area and perimeter at 1 cm below the lowest renal vein expanded by 61.6% ( P < 0.001) and 10.7% ( P < 0.01), respectively. At 5 cm below the lowest renal vein, the expansion of cross-sectional area and perimeter were 43.9% ( P < 0.01) and 10.7% ( P = 0.002), respectively. The major axis of the inferior vena cava was oriented in a left-anterior oblique position in all patients, averaging 20° from the horizontal plane. There was significant underestimation of inferior vena cava maximal diameter by horizontal measurement. In pre-resuscitation scans, at 1 cm and 5 cm below the lowest renal vein, the discrepancy between the horizontal and major axis diameter was 2.1 ± 1.2 mm ( P < 0.001) and 1.7 ± 1.0 mm ( P < 0.001), respectively, while post-resuscitation studies showed the same underestimation at 1 cm and 5 cm below the lowest renal vein to be 2.2 ± 1.2 mm ( P < 0.01) and 1.9 ± 1.0 mm ( P < 0.01), respectively.ConclusionsThere is significant anisotropic variability of infrarenal inferior vena cava geometry with significantly greater expansive and compressive forces in the minor axis. There can be significant volumetric changes in the inferior vena cava with associated perimeter changes but the major axis left-anterior oblique caval configuration is always maintained. These significant dynamic forces may impact inferior vena cava filter stability after implantation. The consistent major axis left-anterior oblique obliquity may lead to underestimation of the inferior vena cava diameter used in standard anteroposterior venography, which may influence initial filter selection.

Raised Object on a Planar Surface Stroked Across the Fingerpad: Responses of Cutaneous Mechanoreceptors to Shape and Orientation

1998 ◽  
Vol 80 (5) ◽  
pp. 2446-2466 ◽  
Author(s):  
R. H. Lamotte ◽  
R. M. Friedman ◽  
C. Lu ◽  
P. S. Khalsa ◽  
M. A. Srinivasan
Keyword(s):  
Horizontal Plane ◽  
Major Axis ◽  
Skin Surface ◽  
Minor Axis ◽  
Type I ◽  
Planar Surface ◽  
Cutaneous Mechanoreceptors ◽  
Cross Sectional ◽  
Orthogonal Axis ◽  
Object Shape

LaMotte, R. H., R. M. Friedman, C. Lu, P. S. Khalsa, and M. A. Srinivasan. Raised object on a planar surface stroked across the fingerpad: responses of cutaneous mechanoreceptors to shape and orientation. J. Neurophysiol. 80: 2446–2466, 1998. The representations of orientation and shape were studied in the responses of cutaneous mechanoreceptors to an isolated, raised object on a planar surface stroked across the fingerpad. The objects were the top portions of a sphere with a 5-mm radius, and two toroids each with a radius of 5 mm along one axis and differing radii of 1 or 3 mm along the orthogonal axis. The velocity and direction of stroking were fixed while the orientation of the object in the horizontal plane was varied. Each object was stroked along a series of laterally shifted, parallel, linear trajectories over the receptive fields of slowly adapting, type I (SA), and rapidly adapting, type I (RA) mechanoreceptive afferents innervating the fingerpad of the monkey. “Spatial event plots” (SEPs) of the occurrence of action potentials, as a function of the location of each object on the receptive field, were interpreted as the responses of a spatially distributed population of fibers. That portion of the plot evoked by the curved object (the SEPc) provided a representation of the shape and orientation of the two-dimensional outline of the object in the horizontal plane in contact with the skin. For both SAs and RAs, the major vector of the SEPc, obtained by a principal components analysis, was linearly related to the physical orientation of the major axis of each toroid. The spatial distribution of discharge rates [spatial rate surface profiles (SRSs), after plotting mean instantaneous frequency versus spatial locus within the SEPc] represented object shape in a third dimension, normal to the skin surface. The shape of the SA SRSs, well fitted by Gaussian equations, better represented object shape than that of the RA SRSs. A cross-sectional profile along the minor axis [spatial rate profile (SRP)] was approximately triangular for SAs. After normalization for differences in peak height, the falling slopes of the SA SRPs increased, and the base widths decreased with curvature of the object's minor axis. These curvature-related differences in slopes and widths were invariant with changes in object orientation. It is hypothesized that circularity in object shape is coded by the constancy of slopes of SA SRPs between peak and base and that the constancy of differences in the widths and falling slopes evoked by different raised objects encodes, respectively, the differences in their sizes and shapes regardless of differences in their orientation on the skin.

Study of jets from rectangular nozzles with square grooves

2011 ◽  
Vol 115 (1165) ◽  
pp. 187-196 ◽  
Author(s):  
P. Arun Kumar ◽  
S. B. Verma ◽  
S. Elangovan
Keyword(s):  
Major Axis ◽  
Minor Axis ◽  
Equivalent Diameter ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Potential Core ◽  
Axis Direction ◽  
Square Configuration ◽  
Hotwire Anemometry ◽  
Axis Switching

AbstractAn experimental study has been carried out to understand jet flow development from plain and grooved rectangular nozzles of aspect ratio 2:1 using two-component hotwire anemometry. Grooves of square configuration (side 4mm) and length 5mm were introduced in the (i) minor-axis, (ii) major-axis and, (iii) in both minor- and major-axes directions. The equivalent diameter of the plain rectangular nozzle is 37·5mm. Studies were carried out for a nominal jet exit velocity of 20ms−1and for Reynolds number based on equivalent diameter of 54,000. The introduction of grooves in either plane does not show any influence on the potential-core length but results in faster jet-decay thereafter. It is observed that the grooves when introduced in minor-axis direction inhibit the jet growth in that plane while promoting the jet growth along major-axis plane and hence, delays the phenomena of axis-switching. However when introduced in major-axis direction, the grooves promote jet growth along major-axis plane while inhibiting jet-growth in minor-axis plane. Cross-sectional contours of mean-velocity suggest that the grooves modify the process of overall jet development significantly in the plane in which they are introduced relative to the plain jet and hence, significantly affect the axis-switching location in each case.

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