scholarly journals STUDIES ON CILIA

1965 ◽  
Vol 26 (3) ◽  
pp. 805-834 ◽  
Author(s):  
Peter Satir
Keyword(s):  
Cross Section ◽  
Length Change ◽  
The Body ◽  
Cell Of Origin ◽  
Ciliary Movement ◽  
The Matrix ◽  
Morphological Specialization ◽  
Dense Band ◽  
The Cross ◽  
Different Order

Termination of peripheral filaments of the axoneme of gill cilia of fresh-water mussels (Elliptio or Anodonta) occurs in characteristic fashion: (a) subfiber b of certain doublets ends leaving a single simplified tubular unit; (b) the wall of the unit becomes thick and may even obliterate the interior; and (c) the filament drops out of the 9 + 2 pattern. The order in which doublets begin simplifying is also characteristic. This may be determined by numbering the filaments, those with the bridge being 5–6, with the direction of numbering determined by the apparent enantiomorphic configuration (I to IV) of the cross-section. Shorter filaments can be identified in simplifying tips with mixed double and single peripheral units. In this material, laterofrontal cirri show a morphological specialization in the region where individual cilia simplify. The cilia studied run frontally from the body of the cirrus and point in the direction of effective stroke. The longest filaments (Nos. 3, 4, 5, 6, 7) appear as the doublets at the bottom of the cross-section, nearest the surface of the cell of origin. Above them, and above the central pair, a dark band (a section of a dense rod) runs through the matrix. The remaining filaments are the single units. Effective-pointing frontal and lateral ciliary tips end in a fashion similar to laterofrontal tips, although no dense band is present. For all effective-pointing tips studied, the order in which the peripheral filaments end appears to be Nos. (9, 1), 8, 2, 7, 6, 3, 4, 5. However, recovery-pointing lateral tips show a different order: Nos. 7, 6, 8, 5, 9, 4, 1 (3, 2), although the longer filaments are still at the bottom of the cross-section. In simple models of ciliary movement involving contraction of the peripheral filaments, filaments at the top of the cross-section should be longer, if any are. Such models are not supported by the evidence here. These results can be interpreted as supporting sliding-filament models of movement where no length change of peripheral filaments occurs.

scholarly journals Threshold of the upper airway cross-section for hypopnea onset during sleep and its identification under waking condition

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hongyi Lin ◽  
Cunting Wang ◽  
Han Zhang ◽  
Huahui Xiong ◽  
Zheng Li ◽  
...  
Keyword(s):  
Cross Section ◽  
Airway Resistance ◽  
Upper Airway ◽  
The Body ◽  
Sigmoid Function ◽  
Fluid Accumulation ◽  
Normal Breathing ◽  
Obstructive Sleep ◽  
The Cross ◽  
Shape Changes

Abstract Background There is currently no method that can predict whether or under what condition hypopnea, even obstructive sleep apnea (OSA), will occur during sleep for individuals based on credible parameters measured under waking condition. We propose a threshold concept based on the narrowest cross-sectional area of the upper airway (CSA-UA) and aim to prove our hypothesis on the threshold of the area for hypopnea onset (TAHO), which can be used as an indicator of hypopnea onset during sleep and measured while awake. Methods We performed magnetic resonance imaging for 20 OSA patients to observe CSA-UA changes during fluid accumulation in the neck caused by elevating their legs, and identified TAHO by capturing the sudden enlargement in CSA-UA. Correlation analyses between TAHO and the body mass index (BMI), and between the reduction in CSA-UA and the increase in the neck circumference (NC) with fluid accumulation were performed. Logistic regression analysis was performed for identifying OSA patients based on the behaviors of their CSA-UA changes during leg raising. Shape changes of airway cross-section were also investigated. Results Four CSA-UA change patterns after fluid redistribution were identified. Six patients had similar CSA-UA variation behaviors observed in healthy subjects. From the other three change patterns involving 14 patients, a threshold value of CSA-UA 0.63 ± 0.21 cm2 was identified for normal breathing. Data showed a positive correlation between TAHO and BMI (r = 0.681, p = 0.0007), and a negative correlation between the reduction in CSA-UA and the increase in NC (r = − 0.513, p = 0.051) with fluid accumulation. A sigmoid function for the probability of being a OSA patient p = 1/[1 + exp. (4.836 + 3.850 t-8.4 h)] was obtained to effectively separate OSA patients from normal subjects. The upper airway narrowing occurred in anteroposterior, lateral, or both directions, suggesting different tendencies of upper airway collapse in patients. Three types of shape changes in the cross-section of the upper airway, which had different effects on airway resistance, were measured. Conclusions Our findings prove TAHO hypothesis. The threshold measured while awake for normal breathing can be used clinically as the indicator of hypopnea onset during sleep, and therefore to identify OSA patients under waking condition and design effective personalized treatments for OSA patients. Both shape and size changes in the cross-section of the upper airway affect airway resistance significantly. Shape change in the cross-section of the upper airway can provide key clinical information on the collapse patterns of the upper airway for individuals.

Fourier transform of the general expression for the magnetic anomaly due to a long horizontal cylinder

Geophysics ◽  
1980 ◽  
Vol 45 (6) ◽  
pp. 1091-1093 ◽  
Author(s):  
K. S. R. Murthy ◽  
D. C. Mishra
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Magnetic Anomaly ◽  
Cross Section ◽  
General Expression ◽  
Horizontal Cylinder ◽  
The Body ◽  
The Cross ◽  
Three Components

The general expression for the magnetic anomaly due to a long horizontal cylinder (Gay, 1965) applicable to all three components, i.e., ΔT, ΔZ, and ΔH, is transformed to obtain its characteristics in the frequency domain. The transformed expression clearly demonstrates that its decay is primarily controlled by the depth of the model, while its value at ο = 0 depends upon the nature of magnetization and the cross‐section of the body. It is possible, therefore, to derive the parameters of the causative model directly from the computed transform of the measured anomaly.

Modeling of the impact of hold-down forces on the accuracy of the workpiece shape using the finite element method

2021 ◽  
pp. 9-20
Author(s):  
A.V. Zaitsev ◽  
A.N. Izosimov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
The Body ◽  
Machining Process ◽  
Mechanical Processing ◽  
The Finite Element Method ◽  
The Cross ◽  
The Impact ◽  
Element Method

In the article, the modeling of the impact of hold-down forces on the accuracy of the shape of the workpiece using the finite element method was carried out. The operation of mechanical processing (turning cut) of a workpiece of the body of rotation type on a milling machine with basing and fixing along the inner cylindrical surface of the workpiece is considered. The study was conducted for four different types of machine retaining devices used on machines of this group. A consistent description and illustration of the method of modeling the process of the impact of hold-down forces on the workpiece is made for each type of the device under consideration. The force constraints and effects imposed on the model are described and illustrated, the parameters of the finite element grid used in modeling are presented, the displacement profiles obtained in the modeling process and the stages of modeling the machining process are described, and the values of the largest deviations from the shape of the workpiece are determined. The results of the modeling are presented: a qualitative picture of the shape errors obtained as a result of mechanical processing — the values of the largest deviation from the roundness and the largest deviation from the cross-section profile of the workpiece to be processed, as well as the shape of the cutting obtained in the cross-section of the workpiece for each type of the devices under consideration. On the basis of the obtained results, estimates of the degree of accuracy of the shape and the relative geometric accuracy provided by the considered devices were made in accordance with GOST 24643–81. The conclusion is made about the suitability of using the considered variants of machine retaining devices for the proposed technological process according to the criterion of the provided accuracy of the shape of the processed surface. English version of the article is available at URL: https://panor.ru/articles/modeling-the-influence-of-the-fastening-forces-on-the-accuracy-of-the-workpiece-shape-using-the-finite-element-method/65043.html

Electron capture in fast collisions I. Capture by fast protons in atomic hydrogen

1961 ◽  
Vol 264 (1317) ◽  
pp. 277-288 ◽  
Keyword(s):  
Perturbation Theory ◽  
Matrix Element ◽  
Electron Capture ◽  
Cross Section ◽  
Atomic Hydrogen ◽  
Incoming Particle ◽  
The Matrix ◽  
Explicit Formulae ◽  
The Cross ◽  
Fast Protons

Formal perturbation theory is employed to obtain the matrix element for electron capture by fast particles of mass M B and charge Z B from atoms of mass M A and charge Z A , allowing for the internuclear potential and distortion by the incoming particle. Explicit formulae are presented for the Is— Is transition. Detailed calculations were carried out for protons in atomic hydrogen. For this case distortion significantly reduces the cross-section at proton energies below 100 keV, but at higher energies its effects and those of the internuclear potential largely cancel each other.

A HREM study of the interfaces between TiO2 precipitates and the Al2O3 matrix in star sapphire

1992 ◽  
Vol 50 (1) ◽  
pp. 228-229
Author(s):  
S.Q. Xiao ◽  
A. H. Heuer ◽  
P. Pirouz
Keyword(s):  
Cross Section ◽  
Lattice Mismatch ◽  
Misfit Dislocations ◽  
Regular Array ◽  
Lattice Constants ◽  
Small Precipitate ◽  
S Matrix ◽  
The Matrix ◽  
The Mean ◽  
The Cross

The asterism, or star effect, present in star sapphire (Ti-doped A12O3) single crystals is known to arise from the needle-like rutile(r) (TiO2) precipitates in the sapphire(s) matrix. The specific orientation relationship between the precipitates and the matrix is {100}r//{0003}s and <011>r//<1010>s . In this work we report a HREM study of the rutile/sapphire interface.The cross-section perpendicular to the needle axis of a very small precipitate, which is coherent, or has just one misfit dislocation at its interface, is a rhombus; the precipitate/matrix interface (habit plane) is {111}r{1123}s. As the coherency break down and misfit dislocations are introduced into the interface, the shape of the cross-section becomes nearly square; the two orthogonal interfaces are {100}r//0003}s and {011}r//{1120}s. Larger precipitates show rectangular interfaces elongated along the {100}r//{0003}s interface (Fig.l). A regular array of misfit dislocations with Burger vector b = 1/3<0001>S are present at the {011}r//{1120}s interface, the mean distance between every two adjacent 1/3<0001>S misfit dislocations being 8.7 nm which compensates exactly the 5.9% lattice mismatch estimated from the lattice constants of these two structures. Similarly, a regular array of misfit dislocations with Burgers vector b = 1/3<1010>S at the {100}r//{0003}s interface compensates the 4.5% lattice mismatch at that interface.

Effect of milling on the microstructure and mechanical property of austenite stainless steel

2020 ◽  
Vol 62 (12) ◽  
pp. 1181-1186
Author(s):  
Huanchun Wu ◽  
Wenxin Ti ◽  
Guodong Zhang ◽  
Fei Xue ◽  
Chengtao Li ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Cross Section ◽  
Electron Backscatter Diffraction ◽  
Martensite Phase ◽  
Austenite Stainless Steel ◽  
The Matrix ◽  
Milled Surface ◽  
The Cross ◽  
Nanocrystalline Layer ◽  
Deformation Layer

Abstract A milling induced deformation layer of Z3CN20.09M, 304L and 316L austenite stainless steel (SS) was investigated by electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and a nanoindenter. The results indicated that the deformation layer was formed with a depth of about 200 μm, including a nanocrystalline layer within the range of 3 μm at the subsurface and followed by a large amount of persistent slip bands (PSBs). The significant plastic deformation was observed on the cross section of deformation layer with a range of about 80 μm for Z3CN20.09M and 304L SS, while being only about 30 μm for 316L SS. The highest residual stress tested on the milled surface reached about 1000 MPa, which can be attributed to the fact that a deformed martensite phase was formed at the surface during the milling operation. The nanohardness increased by 20-60 % on the cross section of the deformation layer as compared to the matrix.

scholarly journals Extensions of d'Alembert's paradox for elongated bodies

2015 ◽  
Vol 471 (2181) ◽  
pp. 20150106
Author(s):  
Philippe R. Spalart
Keyword(s):  
Cross Section ◽  
Unit Length ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Added Mass ◽  
The Body ◽  
Pitching Moment ◽  
Constant Cross Section ◽  
Slender Body Theory ◽  
The Cross

The steady incompressible irrotational flow past a three-dimensional body of any shape generates no forces. The historic paradox refers only to drag, but lift is also zero, which has been known but not emphasized. The new material concerns a body with a long constant cross section, such as a train. The final results for forces and moments are very simple. With zero angle of attack, we show that the force vectors on the front and rear parts of the body are each (asymptotically) equal to zero, if the pressure is referred to the freestream pressure. The lift and drag coefficients, based on frontal area, vanish proportionally to d / l and ( d / l ) 2 , respectively, where d / l is the diameter-to-length ratio. This applies to any shape of the cross section, and of the ends. With an angle of attack, the nose and tail forces are non-zero but depend only on the angle of attack and the cross section's added mass per unit length. The pitching moment is proportional to the total added mass and the sine of twice the angle of attack. The present results clarify slender-body theory results. The practical consequence is that, for a long body with constant cross section, the shape of the nose or the tail is irrelevant to its own ‘partial’ drag and lift, and to the pitching moment.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

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