scholarly journals Transversal otolithic membrane deflections evoked by the linear accelerations

2019 ◽  
Author(s):  
V. Goussev

AbstractConsidered is the model of the transversal utricle membrane deflections evoked by the linear accelerations. The real 3D utricle membrane structure was simplified by considering its middle section and evaluating its elastic properties in 2D space. The steady state transversal deflections along the membrane are analytically evaluated and numerically simulated using the 2D elasticity theory. The transversal deflections are found to be more expressive and stronger as compared to the conventional longitudinal deformations. The revealed properties could be used for explanation of the transduction processes in the otholith organ. Based on the implemented modeling approach the new otolithic membrane mechanical properties are discussed and new explanations for the available experimental data are given.

2019 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Valeri Goussev

Considered is the model of the transversal utricle membrane deflections evoked by the linear accelerations. The basic idea underlying this consideration is that the linear accelerations can cause both longitudinal and transversal deformations when acting along the membrane in the buckling way. The real 3D utricle membrane structure was simplified by considering its middle section and evaluating its elastic properties in 2D space. The steady state transversal deflections along the membrane are analytically evaluated and numerically simulated using the 2D elasticity theory. The transversal deflections are found to be more expressive and stronger as compared to the conventional longitudinal deformations. The maxima of longitudinal deformations and transversal deflections are observable in different regions of the utricle membrane. The revealed properties could be used for explanation of the transduction processes in the otolith organ. Based on the implemented modeling approach the new otolithic membrane mechanical properties are discussed and new explanations for the available experimental data are given.


1985 ◽  
Vol 248 (5) ◽  
pp. C498-C509 ◽  
Author(s):  
D. Restrepo ◽  
G. A. Kimmich

Zero-trans kinetics of Na+-sugar cotransport were investigated. Sugar influx was measured at various sodium and sugar concentrations in K+-loaded cells treated with rotenone and valinomycin. Sugar influx follows Michaelis-Menten kinetics as a function of sugar concentration but not as a function of Na+ concentration. Nine models with 1:1 or 2:1 sodium:sugar stoichiometry were considered. The flux equations for these models were solved assuming steady-state distribution of carrier forms and that translocation across the membrane is rate limiting. Classical enzyme kinetic methods and a least-squares fit of flux equations to the experimental data were used to assess the fit of the different models. Four models can be discarded on this basis. Of the remaining models, we discard two on the basis of the trans sodium dependence and the coupling stoichiometry [G. A. Kimmich and J. Randles, Am. J. Physiol. 247 (Cell Physiol. 16): C74-C82, 1984]. The remaining models are terter ordered mechanisms with sodium debinding first at the trans side. If transfer across the membrane is rate limiting, the binding order can be determined to be sodium:sugar:sodium.


Recycling ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Francesco Paolo La Mantia ◽  
Maria Chiara Mistretta ◽  
Vincenzo Titone

In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit for the experimental values of both rheological and mechanical properties.


1966 ◽  
Vol 39 (5) ◽  
pp. 1436-1450
Author(s):  
K. J. Smith ◽  
D. Puett

Abstract The birefringence of natural rubber networks at large deformations has been investigated experimentally and compared with the simultaneously determined stress—strain behavior. Our data is analyzed using a statistical theory of flexibly jointed chains, derived herein, which is believed to be more significant for the particular range of deformation used than the theories of Treloar and of Kuhn and Grün. In addition, the experimental data of Saunders is commented on in light of our theoretical development. We find that for network extensions exceeding those of the Gaussian region there is little correlation between the observed and theoretical behavior of the stress and birefringence (based upon the theory of flexibly jointed chains) and this lack of agreement is attributed to the fact that the statistical parameters needed for the description of the optical chain properties differ in magnitude from those required for the mechanical properties. Furthermore, by considering the points of incipient crystallization the strain behavior of the stress-optical coefficient is highly indicative of nonGaussian behavior rather than crystallization, and therefore yields strong support for the position that nonGaussian behavior does exist in rubber networks.


2007 ◽  
Vol 23 ◽  
pp. 119-122
Author(s):  
Cristina Teișanu ◽  
Stefan Gheorghe ◽  
Ion Ciupitu

The most important features of the self-lubricating bearings are the antifriction properties such as friction coefficient and wear resistence and some mechanical properties such as hardness, tensile strength and radial crushing strength. In order to improve these properties new antifriction materials based on iron-copper powders with several additional components (tin, lead and molybdenum disulphide) have been developed by PM techniques. To find the optimal relationship between chemical compositions, antifriction and mechanical properties, in this paper a mathematical model of the sintering process is developed, which highlighted the accordance of the model with data by regression analysis. For the statistical processing of the experimental data the VH5 hardness values of the studied materials were considered. The development of mathematical model includes the enunciation of the model, the establishment of the performance function (optimization) and the establishment of the model equations and verifying. The accordance of the model with experimental data has been highlighted by regression analysis


2013 ◽  
Vol 671-674 ◽  
pp. 1761-1765
Author(s):  
Yong Liu ◽  
Chun Ming Song ◽  
Song Lin Yue

In order to get mechanical properties ,some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. And a group of tests on RPC with 5% steel-fiber under penetration were also conducted to validate the performance to impact. The penetration tests are carried out by the semi-AP projectiles with the diameter of 57 mm and earth penetrators with the diameter of 80 mm, and velocities of the two kinds of projectiles are 300~600 m/s and 800~900 m/s, respectively. By contrast between the experimental data and the calculation results of C30 reinforced concrete by using experiential formula under penetration, it shows that the resistance of steel-fiber RPC to penetration is 3 times as that of general C30 reinforced concrete.


2015 ◽  
Vol 44 (43) ◽  
pp. 18769-18779 ◽  
Author(s):  
Philippe F. Weck ◽  
Eunja Kim ◽  
Veena Tikare ◽  
John A. Mitchell

The elastic properties and mechanical stability of zirconium alloys and zirconium hydrides have been investigated within the framework of density functional perturbation theory. Results show that the lowest-energy Pn3̄m δ-ZrH1.5 phase is not mechanically stable.


Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li

The test of austenitic stainless steel specimens with strain control mode of pre-strain was carried out. The range of pre-strain is 4%, 5%, 6%, 7%, 8%, 9% and 10% on austenitic stainless steel specimens, then tensile testing of these samples was done and their mechanical properties after pre-strain were gotten. The results show that the pre-strain has little effect on tensile strength, and enhances the yield strength more obviously. According to the experimental data, we get a relational expression of S30408 between the value of yield strength and pre-strain. We can obtain several expressions about different kinds of austenitic stainless steel by this way. It is convenient for designers to get the yield strength of austenitic stainless steel after pre-strain by the value of pre-strain and the above expression.


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