scholarly journals The Biomechanics of Erections: Modeling the Penis as a One-Comparment Pressurized Vessel vs. Modeling it as a Two-Compartments Pressurized Vessel

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
A. Mohamed ◽  
A. Erdman ◽  
G. Timm
Keyword(s):  
Structural Integrity ◽  
Tunica Albuginea ◽  
Three Dimensional ◽  
The Body ◽  
Physical Models ◽  
Von Mises Stress ◽  
Two Dimensional ◽  
Biomechanical Models ◽  
Significant Difference ◽  
The One

Previous biomechanical models of the penis that have attempted to simulate penile erections have either been limited to two-dimensional geometry, simplified three-dimensional geometry or made inaccurate assumptions altogether. Most models designed the shaft of the penis as a one-compartment pressurized vessel fixed at one end, when in reality it is a two-compartments pressurized vessel, in which the compartments diverge as they enter the body and are fixed at two separate points. This study began by designing simplified two-dimensional and three-dimensional models of the erect penis using Finite Element Analysis (FEA) methods with varying anatomical considerations for analyzing structural stresses, axial buckling and lateral deformation. The study then validated the results by building physical models replicating the computer models. Finally a more complex and anatomically accurate model of the penis was designed and analyzed. There was a significant difference in the peak von-Mises stress distribution between the one-compartment pressurized vessel and the more anatomically correct two-compartments pressurized vessel. Furthermore, the two-compartments diverging pressurized vessel was found to have more structural integrity when subject to external lateral forces than the one-compartment pressurized vessel. This study suggests that Mother Nature has favored an anatomy of two corporal cavernosal bodies separated by a perforated septum as opposed to one corporal body, due to better structural integrity of the tunica albuginea when subject to external forces.

The Biomechanics of Erections: Two- Versus One-Compartment Pressurized Vessel Modeling of the Penis

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Ahmed M. Mohamed ◽  
Arthur G. Erdman ◽  
Gerald W. Timm
Keyword(s):  
Structural Integrity ◽  
Tunica Albuginea ◽  
Compartment Model ◽  
3D Models ◽  
Lateral Force ◽  
The Body ◽  
Physical Models ◽  
Biomechanical Models ◽  
Significant Difference ◽  
External Forces

Previous biomechanical models of the penis simulated penile erections utilizing 2D geometry, simplified 3D geometry or made inaccurate assumptions altogether. These models designed the shaft of the penis as a one-compartment pressurized vessel fixed at one end when in reality it is a two-compartment pressurized vessel in which the compartments diverge as they enter the body and are fixed at two separate anatomic sites. This study utilizes the more anatomically correct two-compartment penile model to investigate erectile function. Simplified 2D and 3D models of the erect penis were developed using the finite element method with varying anatomical considerations for analyzing structural stresses, axial buckling, and lateral deformation. This study then validated the results by building and testing corresponding physical models. Finally, a more complex and anatomically accurate model of the penis was designed and analyzed. When subject to a lateral force of 0.5 N, the peak equivalent von Mises (EVM) stress in the two-compartment model increased by about 31.62%, while in the one-compartment model, the peak EVM stress increased by as high as 70.11%. The peak EVM stress was 149 kPa in the more complex and anatomically accurate penile model. When the perforated septum was removed, the peak EVM stress increased to 455 kPa. This study verified that there is significant difference between modeling the penis as a two- versus a one-compartment pressurized vessel. When subjected to external forces, a significant advantage was exhibited by two corporal based cavernosal bodies separated by a perforated septum as opposed to one corporal body. This is due to better structural integrity of the tunica albuginea when subjected to external forces.

Unsteady flow of gas at high pressure into a closed volume filled with liquid

2020 ◽  
Vol 6 (4) ◽  
pp. 127-140
Author(s):  
Maksim V. Alekseev ◽  
Ivan S. Vozhakov ◽  
Sergey I. Lezhnin
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Water System ◽  
Liquid Lead ◽  
Asymptotic Model ◽  
Closed Volume ◽  
Two Dimensional ◽  
Open Platform ◽  
Significant Difference ◽  
The One

Within the framework of 2D (two-dimensional, axisymmetric) and 3D (three-dimensional) formulations of the problem, this article presents a numerical simulation of the process of gas outflow under pressure into a closed container partially filled with liquid. The authors have performed the numerical modeling using the open platform OpenFOAM with the help of a solver based on the method of liquid volumes (VOF method) with a standard k-e turbulence model. A comparison is made with the one-dimensional (1D) asymptotic model, in which the oscillations of the fluid as a whole are determined by the enthalpy balance. A numerical study of the evolution of pressure during gas outflow is carried out. The results show that the physical properties of the fluid used affect the amplitude and frequency of the pulsations. The modeling has shown that gas flows into water in the form of a jet, and a projectile forms in liquid lead near the hole through which it flows out. The significant influence of three-dimensional effects on the evolution of gas outflow into liquid is demonstrated. Satisfactory agreement was obtained for both two-dimensional and three-dimensional calculations and the results obtained using the asymptotic model. For the “gas — water” system, the results of calculations by the asymptotic model give a significant difference from the results of numerical calculations.

F.VIII R:Ag in Hepatitis

1979 ◽  
Author(s):  
R. Kotitschke ◽  
J. Scharrer
Keyword(s):  
Chronic Hepatitis ◽  
Blood Donors ◽  
Blood Donation ◽  
Normal Population ◽  
Rabbit Antiserum ◽  
Two Dimensional ◽  
Plastic Plate ◽  
Significant Difference ◽  
Acute Hepatitis B ◽  
The One

F.VIII R:Ag was determined by quantitative immunelectrophoresis (I.E.) with a prefabricated system. The prefabricated system consists of a monospecific f.VIII rabbit antiserum in agarose on a plastic plate for the one and two dimensional immunelectrophoresis. The lognormal distribution of the f.VIII R:Ag concentration in the normal population was confirmed (for n=70 the f.VIII R:Ag in % of normal is = 95.4 ± 31.9). Among the normal population there was no significant difference between blood donors (one blood donation in 8 weeks; for n=43 the f.VIII R:Ag in % of normal is = 95.9 ± 34.0) and non blood donors (n=27;f.VIII R:Ag = 94.6 ± 28.4 %). The f.VIII R:Ag concentration in acute hepatitis B ranged from normal to raised values (for n=10, a factor of 1.8 times of normal was found) and was normal again after health recovery (n=10, the factor was 1.0). in chronic hepatitis the f.VIII R:Ag concentration was raised in the majority of the cases (for n=10, the factor was 3.8). Out of 22 carrier sera 20 showed reduced, 2 elevated levels of the f.VIII R:Ag concentration. in 5 sera no f.VIII R:Ag could be demonstrated. The f.VIII R:Ag concentration was normal for n=10, reduced for n=20 and elevated for n=6 in non A-non B hepatitis (n=36). Contrary to results found in the literature no difference in the electrophoretic mobility of the f.VIII R:Ag was found between hepatitis patients sera and normal sera.

scholarly journals Acoustic Cell Patterning in Hydrogel for Three-Dimensional Cell Network Formation

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Kyo-in Koo ◽  
Andreas Lenshof ◽  
Le Thi Huong ◽  
Thomas Laurell
Keyword(s):  
Network Formation ◽  
Umbilical Vein ◽  
Three Dimensional ◽  
Extrusion Process ◽  
Fibroblast Cells ◽  
Glass Capillary ◽  
Cell Network ◽  
Significant Difference ◽  
The One ◽  
Umbilical Vein Endothelial Cells

In the field of engineered organ and drug development, three-dimensional network-structured tissue has been a long-sought goal. This paper presents a direct hydrogel extrusion process exposed to an ultrasound standing wave that aligns fibroblast cells to form a network structure. The frequency-shifted (2 MHz to 4 MHz) ultrasound actuation of a 400-micrometer square-shaped glass capillary that was continuously perfused by fibroblast cells suspended in sodium alginate generated a hydrogel string, with the fibroblasts aligned in single or quadruple streams. In the transition from the one-cell stream to the four-cell streams, the aligned fibroblast cells were continuously interconnected in the form of a branch and a junction. The ultrasound-exposed fibroblast cells displayed over 95% viability up to day 10 in culture medium without any significant difference from the unexposed fibroblast cells. This acoustofluidic method will be further applied to create a vascularized network by replacing fibroblast cells with human umbilical vein endothelial cells.

A Liberating Experience. On Becoming a Work of Art

2020 ◽  
Vol 7 (2) ◽  
pp. 411-430
Author(s):  
Maja Tabea Jerrentrup
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
The Other ◽  
Work Of Art ◽  
Other Hand ◽  
Film Clips ◽  
Long Time ◽  
The One ◽  
Body Painting ◽  
Dimensional Surface

Abstract The art of bodypainting that is fairly unknown to a wider public turns the body into a canvas - it is a frequently used phrase in the field of bodypainting that illustrates the challenge it faces: it uses a three-dimensional surface and has to cope with its irregularities, but also with the model’s abilities and characteristics. This paper looks at individuals who are turned into art by bodypainting. Although body painting can be very challenging for them - they have to expose their bodies and to stand still for a long time while getting transformed - models report that they enjoy both the process and the result, even if they are not confident about their own bodies. Among the reasons there are physical aspects like the sensual enjoyment, but also the feeling of being part of something artistic. This is enhanced and preserved through double staging - becoming a threedimentional work of art and then being staged for photography or film clips. This process gives the model the chance to experience their own body in a detached way. On the one hand, bodypainting closely relates to the body and on the other hand, it can help to over-come the body.

The superiority of three-dimensional physical models to two-dimensional computer presentations in anatomy learning

2018 ◽  
Vol 52 (11) ◽  
pp. 1138-1146 ◽  
Author(s):  
Bruce Wainman ◽  
Liliana Wolak ◽  
Giancarlo Pukas ◽  
Eric Zheng ◽  
Geoffrey R Norman
Keyword(s):  
Three Dimensional ◽  
Physical Models ◽  
Two Dimensional

Two- and Three-Dimensional Simulations of the Flow Around a Cylinder Fitted With Strakes

2012 ◽  
Author(s):  
Bruno S. Carmo ◽  
Rafael S. Gioria ◽  
Ivan Korkischko ◽  
Cesar M. Freire ◽  
Julio R. Meneghini
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Free Stream ◽  
Three Dimensional ◽  
The Body ◽  
Vortex Wake ◽  
Two Dimensional ◽  
Flow Around A Cylinder ◽  
Three Dimensional Simulations ◽  
Angle Of Rotation

Two- and three-dimensional simulations of the flow around straked cylinders are presented. For the two-dimensional simulations we used the Spectral/hp Element Method, and carried out simulations for five different angles of rotation of the cylinder with respect to the free stream. Fixed and elastically-mounted cylinders were tested, and the Reynolds number was kept constant and equal to 150. The results were compared to those obtained from the simulation of the flow around a bare cylinder under the same conditions. We observed that the two-dimensional strakes are not effective in suppressing the vibration of the cylinders, but also noticed that the responses were completely different even with a slight change in the angle of rotation of the body. The three-dimensional results showed that there are two mechanisms of suppression: the main one is the decrease in the vortex shedding correlation along the span, whilst a secondary one is the vortex wake formation farther downstream.

Preliminary Ship Design Using One and Two-Dimensional Models

1999 ◽  
Vol 36 (02) ◽  
pp. 102-112
Author(s):  
Michael D. A. Mackney ◽  
Carl T. F. Ross
Keyword(s):  
Finite Element ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Two Dimensional ◽  
One Dimensional ◽  
Dimensional Finite Element ◽  
Dimensional Models ◽  
Support Conditions ◽  
The One ◽  
Three Dimensional Finite Element

Computational studies of hull-superstructure interaction were carried out using one-, two-and three-dimensional finite element analyses. Simplification of the original three-dimensional cases to one- and two-dimensional ones was undertaken to reduce the data preparation and computer solution times in an extensive parametric study. Both the one- and two-dimensional models were evaluated from numerical and experimental studies of the three-dimensional arrangements of hull and superstructure. One-dimensional analysis used a simple beam finite element with appropriately changed sections properties at stations where superstructures existed. Two-dimensional analysis used a four node, first order quadrilateral, isoparametric plane elasticity finite element, with a corresponding increase in the grid domain where the superstructure existed. Changes in the thickness property reflected deck stiffness. This model was essentially a multi-flanged beam with the shear webs representing the hull and superstructure sides, and the flanges representing the decks One-dimensional models consistently and uniformly underestimated the three-dimensional behaviour, but were fast to create and run. Two-dimensional models were also consistent in their assessment, and considerably closer in predicting the actual behaviours. These models took longer to create than the one-dimensional, but ran in very much less time than the refined three-dimensional finite element models Parametric insights were accomplished quickly and effectively with the simplest model and processor, but two-dimensional analyses achieved closer absolute measure of the displacement behaviours. Although only static analysis with simple loading and support conditions were presented, it is believed that similar benefits would be found for other loadings and support conditions. Other engineering components and structures may benefit from similarly judged simplification using one- and two-dimensional models to reduce the time and cost of preliminary design.

A Study of Water Surface Deformation Due to Tip Vortices Wing-in-Ground Effect

2007 ◽  
Vol 51 (02) ◽  
pp. 182-186
Author(s):  
Tracie J. Barber
Keyword(s):  
Water Surface ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Ground Effect ◽  
Aerodynamic Performance ◽  
The Body ◽  
Vehicle Design ◽  
Two Dimensional ◽  
Tip Vortices ◽  
Wing Tip

The accurate prediction of ground effect aerodynamics is an important aspect of wing-in-ground (WIG) effect vehicle design. When WIG vehicles operate over water, the deformation of the nonrigid surface beneath the body may affect the aerodynamic performance of the craft. The likely surface deformation has been considered from a theoretical and numerical position. Both two-dimensional and three-dimensional cases have been considered, and results show that any deformation occurring on the water surface is likely to be caused by the wing tip vortices rather than an increased pressure distribution beneath the wing.

VALIDITY OF THREE-DIMENSIONAL PHOTONIC SCANNING TECHNIQUE FOR ESTIMATING PERCENT BODY FAT

2013 ◽  
pp. 1-6
Author(s):  
K. SHITARA ◽  
H. KANEHISA ◽  
T. FUKUNAGA ◽  
T. YANAI ◽  
Y. KAWAKAMI
Keyword(s):  
Body Fat ◽  
Lung Volume ◽  
Three Dimensional ◽  
The Body ◽  
Percent Body Fat ◽  
Body Volume ◽  
Mean Values ◽  
Significant Difference ◽  
Human Body Surface ◽  
Estimated Error

Background:Three-dimensional photonic scanning (3DPS) was recently developed to measuredimensions of a human body surface. Objective:The purpose of this study was to explore the validity of bodyvolume measured by 3DPS for estimating the percent body fat (%fat). Design, setting, participants, andmeasurement:The body volumes were determined by 3DPS in 52 women. The body volume was corrected forresidual lung volume. The %fat was estimated from body density and compared with the corresponding referencevalue determined by the dual-energy x-ray absorptiometry (DXA). Results:No significant difference was foundfor the mean values of %fat obtained by 3DPS (22.2 ± 7.6%) and DXA (23.5 ± 4.9%). The root mean squareerror of %fat between 3DPS and reference technique was 6.0%. For each body segment, there was a significantpositive correlation between 3DPS- and DXA-values, although the corresponding value for the head was slightlylarger in 3DPS than in DXA. Residual lung volume was negatively correlated with the estimated error in %fat.Conclusions:The body volume determined with 3DPS is potentially useful for estimating %fat. A possiblestrategy for enhancing the measurement accuracy of %fat might be to refine the protocol for preparing thesubject’s hair prior to scanning and to improve the accuracy in the measurement of residual lung volume.

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