Internal Radius and Dilatation

ABSTRACTThis paper reviews our works about the development of thin composite film based on aligned carbon nanotubes (CNT) forest, embedded in epoxy or PMMA polymer matrix, in order to fabricate membranes dedicated to water purification issue. Indeed, the small internal radius of nanotubes, the smoothness of their inner core and the hydrophobic properties of its interna surface induce remarkable flowing properties for water molecules. In this article, thinnin technology process is investigated to obtain composite film with opened CNT. Different etching techniques as grinding, Chemical Mechanical Polishing (CMP) and isotropic plasma O2ar investigated in term of etching rate and membrane roughness, using AFM and SEM characterizations. Results show CMP process in lapping configuration permits to obtain agreement between high etching rate and membrane roughness. Moreover, to improve water flowing through membrane, O2plasma treatment is used to remove polymer residue spread over CNT. Joint use of lapping and plasma treatment permits to obtain 35μm-thick nanoporous membrane with well-opened protruding nanotubes.

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Analysis of Radiofrequency Lesions in Egg Whites in Vitro Produced by Application of the Tew Electrode for Different Temperatures and Times

Pain Research and Management ◽

10.1155/2015/893136 ◽

2015 ◽

Vol 20 (6) ◽

pp. 316-320 ◽

Cited By ~ 1

Author(s):

Young Suk Kwon ◽

So Young Lim ◽

Jong Ho Kim ◽

Ji Su Jang ◽

Chul Ho Kim ◽

...

Keyword(s):

Distal Radius ◽

Mixed Model ◽

Glass Container ◽

Lesion Size ◽

External Radius ◽

Internal Radius ◽

S 100 ◽

Different Temperatures ◽

Radiofrequency Lesions

BACKGROUND: Understanding the size and shape of radiofrequency lesions is important to reduce side effects when applied to patients.OBJECTIVES: To investigate the radiofrequency lesions produced by the application of the Tew electrode for different temperatures and times.METHODS: The white from a fresh hen’s egg was placed in a rectangular glass container and warmed to 37°C. After immersion of the Tew electrode in the egg white, radiofrequency lesions were produced at 65°C, 70°C, 75°C, 80°C, 85°C and 90°C. For each temperature, photographs were taken at 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s and 120 s. The size of the lesion was measured at each temperature and time. A mixed model was used to analyze the data.RESULTS: The size of the lesion increased with increasing temperature and time. There were statistically significant differences in the size of the internal radius between the 65°C and 70°C groups and the 70°C and 75°C groups, as well as in the 70°C and 75°C groups in the size of the external radius and the 60°C to 80°C groups in the size of the distal radius. The maximum lesion size was produced at 90°C and 120 s, and was 1.06±0.16 mm in internal radius, 0.37±0.15 mm in external radius, 0.39±0.04 mm in distal radius.CONCLUSION: The Tew electrode produces lesions following the contour of the tip, and the internal radius is larger than the external and distal radius. The best combination of temperature and time for lesioning using the Tew electrode is 80°C, for 60 s to 90 s.

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Bearing Capacity of Ring Foundations on Sand Overlying Clay

Applied Sciences ◽

10.3390/app10134675 ◽

2020 ◽

Vol 10 (13) ◽

pp. 4675

Author(s):

Chaowei Yang ◽

Zhiren Zhu ◽

Yao Xiao

Keyword(s):

Bearing Capacity ◽

Friction Angle ◽

Failure Criteria ◽

Unit Weight ◽

Sand Layer ◽

Collapse Mechanisms ◽

Internal Radius ◽

Vertical Bearing ◽

Vertical Bearing Capacity ◽

Ring Foundations

The vertical bearing capacity of rough ring foundations resting on a sand layer overlying clay soil is computed in this study by using finite element limit analysis (FELA). The sands and clays are assumed as elastoplastic models, obeying Mohr–Coulomb and Tresca failure criteria, respectively. Based on the FELA results, design charts are provided for evaluating the ultimate bearing capacity of ring foundations, which is related to the undrained shear strength of the clay, the thickness, the internal friction angle, the unit weight of the sand layer, and the ratio of the internal radius to the external radius of the footing. A certain thickness, beyond which the clay layer has a negligible effect on the bearing capacity, is determined. The collapse mechanisms are also examined and discussed.

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Design and calibration of unicapillary pneumotachographs

Journal of Applied Physiology ◽

10.1152/jappl.1998.84.1.335 ◽

1998 ◽

Vol 84 (1) ◽

pp. 335-343 ◽

Cited By ~ 8

Author(s):

A. Giannella-Neto ◽

C. Bellido ◽

R. B. Barbosa ◽

M. F. Vidal Melo

Keyword(s):

Respiratory Mechanics ◽

Ambient Pressure ◽

Animal Experiments ◽

Small Animal ◽

Positive Pressure ◽

Linear Calibration ◽

Third Order ◽

Order Polynomial ◽

Internal Radius ◽

Volume Measurements

Giannella-Neto, A., C. Bellido, R. B. Barbosa, and M. F. Vidal Melo. Design and calibration of unicapillary pneumotachographs. J. Appl. Physiol.84(1): 335–343, 1998.—This study presents a method for design and calibration of unicapillary pneumotachographs for small-animal experiments. The design, based on Poiseuille’s law, defines a set of internal radius and length values that allows for laminar flow, measurable pressure differences, and minimal interference with animal’s respiratory mechanics and gas exchange. A third-order polynomial calibration (Pol) of the pressure-flow relationship was employed and compared with linear calibration (Lin). Tests were done for conditions of ambient pressure (Pam) and positive pressure (Ppos) ventilation at different flow ranges. A physical model designed to match normal and low compliance in rats was used. At normal compliance, Pol provided lower errors than Lin for mixed (1–12 ml/s), mean (4–10 ml/s), and high (8–12 ml/s) flow rate calibrations for both Pam and Ppos inspiratory tests (P < 0.001 for all conditions) and expiratory tests ( P < 0.001 for all conditions). At low compliance, they differed significantly with 8.6 ± 4.1% underestimation when Lin at Pam was used in Ppos tests. Ppos calibration, preferably in combination with Pol, should be used in this case to minimize errors (Pol = 0.8 ± 0.5%, Lin = 6.5 ± 4.0%, P < 0.0005). Nonlinear calibration may be useful for improvement of flow and volume measurements in small animals during both Pam and Ppos ventilation.

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Energy Levels in Nanowires and Nanorods with a Finite Potential Well

Advances in Condensed Matter Physics ◽

10.1155/2020/4945080 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

G. Gulyamov ◽

A. G. Gulyamov ◽

A. B. Davlatov ◽

Kh. N. Juraev

Keyword(s):

Electron Energy ◽

Quantum Wire ◽

Quantum Wires ◽

Energy Levels ◽

Electron Energy Spectrum ◽

Constant Thickness ◽

Potential Well ◽

Discrete Level ◽

Effective Masses ◽

Internal Radius

The energy of electrons and holes in cylindrical quantum wires with a finite potential well was calculated by two methods. An analytical expression is approximately determined that allows one to calculate the energy of electrons and holes at the first discrete level in a cylindrical quantum wire. The electron energy was calculated by two methods for cylindrical layers of different radius. In the calculations, the nonparabolicity of the electron energy spectrum is taken into account. The dependence of the effective masses of electrons and holes on the radius of a quantum wires is determined. An analysis is made of the dependence of the energy of electrons and holes on the internal and external radii, and it is determined that the energy of electrons and holes in cylindrical layers with a constant thickness weakly depends on the internal radius. The results were obtained for the InP/InAs heterostructures.

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Some Dimensions of the Angular Acceleration Receptor Systems of Cephalopods

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400059634 ◽

1984 ◽

Vol 64 (1) ◽

pp. 55-79 ◽

Cited By ~ 21

Author(s):

Linda Maddock ◽

J. Z. Young

Keyword(s):

Angular Velocity ◽

Frequency Band ◽

Deep Sea ◽

Horizontal Plane ◽

Angular Acceleration ◽

The Body ◽

The Other ◽

Radius Of Curvature ◽

Internal Radius ◽

Neutrally Buoyant

The shapes and dimensions of the statocysts of cephalopods have been measured and compared with the semi-circular canals of vertebrates. The cavities grow much more slowly than the body as a whole, but there are knobs, anticristae, which restrict the cavity, and these grow relatively faster. This ensures that the flow of endolymph across the cupulae remains small. Where the liquid is constrained within canals the radius of curvature of the whole canal, R, is similar to that of fishes, whereas its internal radius, r, is twice as large in non-buoyant and four times as large in deep-sea buoyant cephalopods as in fishes of similar size. As in fishes the restriction is greatest in the horizontal plane, providing for operation at higher frequencies in turning about the yaw axis.The statocysts of seven species of Loligo all have similar proportions. The largest individuals of 16 genera of non-buoyant squids also have these same relative dimensions. The statocyst of Sepia is more like that of non-buoyant than of other buoyant cephalopods but yet differs significantly from that of Loligo at all sizes. On the other hand 21 genera of squids known to be neutrally buoyant are very different. Their statocysts are often larger than in the non-buoyant forms and there is less restriction of the cavity by anticristae. The greater flow of endolymph acting across the cupulae presumably provides greater sensitivity at the lower frequencies of turning of these deep-sea animals.The data suggest that the cristae of the cephalopod statocyst may operate in the frequency band where they act as angular accelerometers whereas the vertebrate semi-circular canals operate at higher frequencies as angular velocity meters.

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Arterial mechanics in the fin whale suggest a unique hemodynamic design

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1994.267.3.r805 ◽

1994 ◽

Vol 267 (3) ◽

pp. R805-R818 ◽

Cited By ~ 4

Author(s):

R. E. Shadwick ◽

J. M. Gosline

Keyword(s):

Thoracic Aorta ◽

Arterial Wall ◽

Carotid Arteries ◽

Fold Increase ◽

Arterial Tree ◽

Balaenoptera Physalus ◽

Descending Aorta ◽

Fin Whale ◽

Internal Radius ◽

Characteristic Pressure

An analysis of the dimensions of the aortic tree and the mechanical properties of arterial wall tissues in the fin whale (Balaenoptera physalus) is presented. The aortic arch is greatly expanded, having an internal radius at an estimated mean blood pressure (13 kPa) that is 2.5 times greater than that of the descending thoracic aorta. At this pressure, the elastic modulus of the arch wall (0.4 MPa) is 30 times less than that of the descending aorta (12 MPa). Consequently, even though some capacitance is provided anteriorly by the relatively compliant innominate and carotid arteries, > 90% of the arterial capacitance resides in the arch. The characteristic pressure wave velocity (C0) and impedance (Z0) were calculated from vessel dimensions and elasticity. A predicted 20-fold increase in Z0 between the arch and thoracic aorta should provide a major reflecting site, effectively uncoupling the arch from the remainder of the arterial tree. The dimensions of the arch relative to the likely pressure wavelengths within it suggest that it acts like a compliant windkessel that greatly reduces the pulsatility of the inflow to the descending aorta, which itself likely acts as a rigid, tapered manifold. It is suggested that the presence of both a highly compliant arch and a relatively rigid descending aorta is an adaptation for diving.

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WALL SHEAR STRESSES IN A FLUID–STRUCTURE INTERACTION MODEL OF PULSE WAVE PROPAGATION

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519414500195 ◽

2014 ◽

Vol 14 (02) ◽

pp. 1450019 ◽

Cited By ~ 2

Author(s):

FAN HE

Keyword(s):

Wave Propagation ◽

Pulse Wave ◽

Fluid Structure Interaction ◽

Interaction Model ◽

Elastic Tube ◽

Tube Model ◽

Pulse Wave Propagation ◽

Fluid Structure ◽

Structure Interaction ◽

Internal Radius

In our prior paper, a fluid–structure interaction model of pulse wave propagation, called the elastic tube model, has been developed. The focus of this paper is wall shear stress (WSS) in this model and the effects of different parameters, including rigid walls, wall thickness, and internal radius. The unsteady flow was assumed to be laminar, Newtonian and incompressible, and the vessel wall to be linear-elastic isotropic, and incompressible. A fluid–structure interaction scheme is constructed using a finite element method. The results demonstrate the elastic tube plays an important role in WSS distributions of wave propagation. It is shown that there is a time delay between the WSS waveforms at different locations in the elastic tube model while the time delay cannot be observed clearly in the rigid tube model. Compared with the elastic tube model, the increase of the wall thickness makes disturbed WSS distributions, however WSS values are increased greatly due to the decrease of the internal radius. The results indicate that the effects of different parameters on WSS distributions are significant. The proposed model gives valid results.

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