Investigation of the Relationship of Muscle Mechanical Characteristics with Biosignal Energy

2006 ◽  
pp. 151-156
Author(s):  
Mečislovas Mariūnas ◽  
Kristina Kojelyte
Keyword(s):  
Mechanical Characteristics ◽  
Relationship Of ◽  
The Relationship

scholarly journals Optimization of Thick-Walled Viscoelastic Hollow Polymer Cylinders by Artificial Heterogeneity Creation: Theoretical Aspects

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2408
Author(s):  
Anton Chepurnenko ◽  
Stepan Litvinov ◽  
Besarion Meskhi ◽  
Alexey Beskopylny
Keyword(s):  
Cylindrical Shell ◽  
Internal Pressure ◽  
High Density Polyethylene ◽  
Mechanical Characteristics ◽  
Optimization Technique ◽  
Creep Process ◽  
Mass Content ◽  
Shell Optimization ◽  
Relationship Of ◽  
The Relationship

A theoretical solution of the problem of thick-walled shell optimization by varying the mechanical characteristics of the material over the thickness of the structure is proposed, taking into account its rheological properties. The optimization technique is considered by the example of a cylindrical shell made of high-density polyethylene with hydroxyapatite subjected to internal pressure. Radial heterogeneity can be created by centrifugation during the curing of the polymer mixed with the additive. The nonlinear Maxwell–Gurevich equation is used as the law describing polymer creep. The relationship of the change in the additive content along with the radius r, at which the structure is equally stressed following the four classical criteria of fracture, is determined in an elastic formulation. Moreover, it is shown that a cylinder with equal stress at the beginning of the creep process ceases to be equally stressed during creep. Finally, an algorithm for defining the relationship of the additive mass content on coordinate r, at which the structure is equally stressed at the end of the creep process, is proposed. The developed algorithm, implemented in the MATLAB software, allows modeling both equally stressed and equally strength structures.

Investigation of the Relationship of Muscle Mechanical Characteristics with Biosignal Energy

2006 ◽  
Vol 113 ◽  
pp. 151-156
Author(s):  
Mečislovas Mariūnas ◽  
Kristina Kojelyte
Keyword(s):  
Mechanical Characteristics ◽  
Extreme Points ◽  
Shift Function ◽  
Energy Equality ◽  
Second Derivatives ◽  
Digital Methods ◽  
Relationship Of ◽  
The Relationship ◽  
Analytical Expressions ◽  
Derivatives Of

Based on biosignal energy equality to the work performed by a muscle, in the estimation of energy dissipation within a biolotronic system, analytical expressions have been derived that have helped to calculate major mechanical characteristics of the muscle including elongation of the muscle, speed and acceleration of such elongation. The paper presents the analysis of relevant digital methods alongside with the formulae for the calculation of major mechanical characteristics when the relationship of a muscle biosignal that is presented in a graphical way. As shown, fatigue of the muscle is characterized by one of extreme points of the phase shift function. The values of the first and the second derivatives of the elongation function may be used for the evaluation of functional capacity of the muscle.

HIV infection changes glomerular podocyte cytoskeletal composition and results in distinct cellular mechanical properties

2007 ◽  
Vol 292 (2) ◽  
pp. F701-F710 ◽  
Author(s):  
R. Tandon ◽  
I. Levental ◽  
C. Huang ◽  
F. J. Byfield ◽  
J. Ziembicki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Stress Fibers ◽  
Wild Type ◽  
Force Microscopy ◽  
Hemodynamic Forces ◽  
Filtration Barrier ◽  
Atomic Force ◽  
Relationship Of ◽  
The Relationship

In addition to forming the selective filtration barrier for the renal glomerulus, podocytes maintain glomerular capillary architecture by opposing distending hemodynamic forces. To understand the relationship of cytoskeletal properties and the mechanical characteristics of podocytes, we studied filamin expression and distribution and measured cell membrane deformability in conditionally immortalized wild-type (WT) mouse podocytes, and in podocytes derived from a mouse model of HIV-associated nephropathy (HIVAN). In the WT cells, filamin and F-actin were localized at the periphery and in prominent stress fibers. In the HIVAN cells, filamin expression was reduced, and stress fibers were sparse. In a microaspiration assay, HIVAN cells ruptured under minimal negative pressure. Atomic force microscopy demonstrated that the WT cells had a stiffness of 17 kPa, whereas the value for the HIVAN cells was 4 kPa. These results demonstrate that the mechanical properties of WT and HIVAN podocytes are markedly different in a manner that is consistent with differences in the composition and arrangement of their cytoskeletons. The mechanical properties of the WT podocytes suggest that these cells can better maintain capillary integrity than the HIVAN podocytes and implicate pathological assembly of the cytoskeleton as a mechanism of HIVAN.

TECHNOLOGICAL SUPPORT OF CONTACT RIGIDITY OF MACHINE PARTS

2021 ◽  
pp. 1-28
Author(s):  
V. F. Bezyazychnyj ◽  
M. N. Dmitrieva
Keyword(s):  
Mechanical Characteristics ◽  
Contact Stiffness ◽  
Turbine Engine ◽  
Technological Support ◽  
Contact Rigidity ◽  
Machine Parts ◽  
Engine Components ◽  
Relationship Of ◽  
The Relationship ◽  
Physical And Mechanical Characteristics

The theoretical provisions on establishing the relationship between the geometric characteristics of the surfaces of contacting parts, as well as the physical and mechanical characteristics of the material of these surfaces on their contact stiffness, including the contact stiffness of the surfaces of parts of high-load gas turbine engine components, are presented. The analysis of dependencies on the relationship of contact stiffness and pliability of surfaces with the technological conditions of their processing by various types of cutting process (turning, milling, grinding) is given.

The Relationship of the Asphalt Mixtures Composition and Physical Mechanical Characteristics of the Coating

2019 ◽  
Vol 974 ◽  
pp. 31-36
Author(s):  
A.I. Trautvain ◽  
Evgeniy A. Yakovlev ◽  
V.A. Grichanikov ◽  
Ye.D. Potar'
Keyword(s):  
Asphalt Concrete ◽  
Work Performance ◽  
Mechanical Characteristics ◽  
Production Control ◽  
Production Quality ◽  
Concrete Mixtures ◽  
Asphalt Mix ◽  
Relationship Of ◽  
The Relationship ◽  
Physical And Mechanical Characteristics

In the course of the work performance the following surveys were carried out: the analysis of the information assurance of the asphalt concrete mixtures production quality, the study of the relationship between the composition of asphalt concrete mixtures and the physical and mechanical characteristics of the coating. This paper presents the results of the analysis of the two types asphalt concrete mixtures qualitative composition and its effect on the physical, mechanical and technological characteristics of the coating. It is established that the deviation of asphalt concrete mixtures in composition from the required values ​​leads to their under-compaction in the coating. It was also found that the increase in the number of inconsistencies in the composition of the asphalt concrete mixture leads to the increase in physical and mechanical characteristics that differ from the requirements of GOST 9128-2013 and GOST 31015-2002. The amount of bitumen on the asphalt concrete main characteristics, the data from the existing AP in the Belgorod Region were used as the information base in assessing the influence of granulometry of the asphalt concrete mineral part. Analysis of the particle size distribution was carried out using the laser analyzer for asphalt concrete AP 7 / 35B. The obtained data will be the basis for further study of the various parameters influence on the asphalt mixes properties, as well as improving the efficiency of the asphalt mix production control system.

FEM Stress Analysis and Sealing Performance of Bolted Flanged Connections Using PTFE Blended Gaskets Under Internal Pressure

2015 ◽  
Author(s):  
Koji Sato ◽  
Akira Muramatsu ◽  
Takashi Kobayashi ◽  
Toshiyuki Sawa
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Mechanical Characteristics ◽  
Leak Rate ◽  
Load Factor ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Relationship Of ◽  
The Relationship ◽  
Good Agreement

The objective of the paper is to examine mechanical characteristics of bolted flanged connection with newly developed PTFE blended gaskets under internal pressure such as the contact gasket stress distribution, the sealing performance, the load factor, reduction in axial bolt load due to creep and the flange hub stress. The relationship between the leak rate and the contact gasket stress for newly developed PTFE blended gasket were measured according to JIS B 2490 as well as the stress - displacement relationship of the gaskets. Then, the leak rate for bolted flanged connection with the PTFE blended gaskets (2inch nominal flange) was measured under internal pressure while changing the bolt preloads. In addition, the load factor and the hub stress were measured experimentally. The changes in each axial bolt force were measured using the strain gauges taking into account gasket creep. Using FEM, the gasket stress distribution, the load factor and the hub stress are analyzed taking into account the creep phenomenon of the PTFE blended gasket. The optimal maximum bolt preload is determined and the FEM results of the load factor and hub stress are in a fairly good agreement with the measured results. The predicted leak rate is fairly coincided with the measured results.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

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