scholarly journals Tensors in Newtonian Physics and the Foundations of Classical Continuum Mechanics

2019 ◽  
Vol 24 (3) ◽  
pp. 79
Author(s):  
George L. Brovko
Keyword(s):  
Mechanical Properties ◽  
Continuum Mechanics ◽  
Constitutive Relations ◽  
Physical And Mechanical Properties ◽  
The Body ◽  
Newtonian Physics ◽  
Axiomatic Construction ◽  
Strain Tensors ◽  
Objective Tensors

In the Newtonian approach to mechanics, the concepts of objective tensors of various ranks and types are introduced. The tough classification of objective tensors is given, including tensors of material and spatial types. The diagrams are constructed for non-degenerate (“analogous”) relations between tensors of one and the same (any) rank, and of various types of objectivity. Mappings expressing dependence between objective tensor processes of various ranks and types are considered. The fundamental concept of frame-independence of such mappings is introduced as being inherent to constitutive relations of various physical and mechanical properties in the Newtonian approach. The criteria are established for such frame-independence. The mathematical restrictions imposed on the frame-independent mappings by the objectivity types of connected tensors are simultaneously revealed. The absence of such restrictions is established exclusively for mappings and equations linking tensors of material types. Using this, a generalizing concept of objective differentiation of tensor processes in time, and a new concept of objective integration, are introduced. The axiomatic construction of the generalized theory of stress and strain tensors in continuum mechanics is given, which leads to the emergence of continuum classes and families of new tensor measures. The axioms are proposed and a variant of the general theory of constitutive relations of mechanical properties of continuous media is constructed, generalizing the known approaches by Ilyushin and Noll, taking into account the possible presence of internal kinematic constraints and internal body-forces in the body. The concepts of the process image and the properties of the five-dimensional Ilyushin’s isotropy are generalized on the range of finite strains.

scholarly journals Regression analysis and statistical examination of Knoop Hardness on abrasion resistance in Lyca Beige Marbles

Filomat ◽  
2020 ◽  
Vol 34 (2) ◽  
pp. 609-614
Author(s):  
Burcu Aydin ◽  
Fusun Yalcin ◽  
Ozge Ozer ◽  
Gurhan Yalcin
Keyword(s):  
Mechanical Properties ◽  
Regression Analysis ◽  
Physical And Mechanical Properties ◽  
Production Method ◽  
Knoop Hardness ◽  
Decomposition Products ◽  
Marble Quarries ◽  
Selection Of

Marbles are secondary decomposition products formed by metamorphism of limestone. Effective classification of marble quarries in terms of quality enables the selection of a sustainable production method and safety application. This evaluation is based on physico-mechanical properties of the samples. Obtained results of physico-mechanical properties of the marbles were statistically analyzed using Stata 14 and SPSS 21 software. The marbles indicated mostly normal physical and mechanical properties. A strong inverse relationship exists between Abrasion Value and Knoop Hardness Determination that indicates a significant nonlinear relationship. Samples were distinguished into 3 groups of close similarity and related properties. The estimated value of the parameters is in the 95 % confidence interval. The equation obtained by regression analysis was used for the determination of resistance to abrasion.

scholarly journals An African violin – The feasibility of using indigenous wood from southern Africa as tonewood

2021 ◽  
Vol 117 (11/12) ◽  
Author(s):  
Martina Meincken ◽  
Gerhard Roux ◽  
Thomas Niesler
Keyword(s):  
Mechanical Properties ◽  
Southern Africa ◽  
Wood Species ◽  
Physical And Mechanical Properties ◽  
Relative Magnitude ◽  
The Body ◽  
String Instruments ◽  
Classification Schemes ◽  
Wind Instrument ◽  
Audio Recordings

The wood used to make musical instruments needs to have particular properties. Depending on its function, such as a soundboard for string instruments or the body of a wind instrument, different properties are desirable to obtain the best musical quality. Several different classification schemes exist that correlate physical and mechanical properties of wood to define desirable ranges for tonewoods, and to allow suitable wood species to be chosen. The physical and mechanical properties of various wood species indigenous to southern Africa were characterised and then assessed in terms of their suitability for violin construction using these classification schemes. The results of this analysis show that the most suitable of the wood species assessed are yellowwood and sapele. These were subsequently used by a professional luthier to build an ‘African’ violin. The sound quality of this instrument was determined subjectively through performances to an audience and more objectively via spectral analysis of audio recordings. This analysis shows clear differences in the relative magnitude of the harmonics between the violin made from indigenous wood and an instrument made with conventional wood species. Despite the differences, yellowwood and sapele were found to be suitable tonewoods, resulting in an instrument with a unique sound.

scholarly journals Comparative Assessment Of Some Physical And Mechanical Properties Of Wood Of Different Scots Pine Climatypes

2021 ◽  
Vol 24 (2) ◽  
pp. 27-36
Author(s):  
Siarhei Rabko ◽  
Aliaksandr Kozel ◽  
Ivan Kimeichuk ◽  
Vasyl Yukhnovskyi
Keyword(s):  
Mechanical Properties ◽  
Scots Pine ◽  
Bending Strength ◽  
Geographical Origin ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Forest Steppe ◽  
Siberian Pine ◽  
North Latitude

For a more efficient and rational use in the production of Scots pine wood of various geographical origin, it is necessary to know its physical and mechanical properties. The purpose of this study was to determine the physical and mechanical properties of wood of 17 climatic ecotypes of Scots pine and to carry out a comparative analysis of the indicators obtained for the studied climatypes separately and when they are grouped into subspecies in accordance with the classification of L.F. Pravdin. The range of the geographical origin of the places of seed procurement is from 47 to 62° north latitude and from 22 to 85° east longitude. The modern density universal testing machine MTS INSIGHT 100 was used for research. As a result of the research, it was found that the density of wood in an absolutely dry state varies from 370 kg/m3 (Kursk climatype) to 524 kg/m3 (Volgograd climatype), and at 12% humidity – from 397 kg/m3 (Kursk climatype) to 550 kg/m3 (Volgograd climatype). The index of the strength of wood of the studied climatypes for compression along the fibres was from 32 MPa (Kursk climatype) to 54 MPa (Volgograd climatype), and for static bending – from 55 to 92 MPa for the Vologda and Ulyanovsk climatypes, respectively. Distribution of Scots pine climatypes into subspecies in accordance with the classification of L.F. Pravdin and the obtained data on the physical and mechanical properties of wood have a certain pattern. The maximum density of wood at 12% moisture is typical for the European Scots pine subspecies is 497±8 kg/m3 , the minimum value of this indicator for the Siberian Scots pine subspecies is 423±30 kg/m3 . An intermediate position is occupied by the subspecies of Lapland pine and Forest-steppe pine with values of 483±16 and 464±12 kg/m3 , respectively. The strength index of wood in the studied subspecies for compression along the fibres ranged from 47±1 MPa (European subspecies) to 33±4 MPa (Siberian subspecies), in the Lapland pine subspecies – 44±2 MPa and somewhat lower in the Forest-steppe pine subspecies – 42±2 MPa. The maximum value of the static bending strength of wood is typical for the European pine subspecies – 78±4 MPa, and the minimum – for the Siberian pine subspecies – 61±14 MPa. This indicator turned out to be equal in subspecies of forest-steppe and Lapland pine and amounted to 72±4 MPa. The practical value of the work lies in identifying the existing differences and variability among climatypes according to the studied physical and mechanical properties of wood and selecting the most promising of them for further breeding purposes

scholarly journals Classifications, Surface Characterization and Standardization of Nanobiomaterials

2013 ◽  
Vol 2 (3) ◽  
pp. 187 ◽  
Author(s):  
Salah H. R. Ali ◽  
Marwah M. Almaatoq ◽  
Abdalla S.A. Mohamed
Keyword(s):  
Mechanical Properties ◽  
Surface Characterization ◽  
Medical Engineering ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Engineering Applications ◽  
Nano Scale ◽  
Body Tissues ◽  
Living Creature

Biomaterials measurement and standardization are necessary for suitable use in medical industries. Nanobiomaterials used in living creature body, taking in account of their biocompatibility, nontoxic and non carcinogenic. These requirements are eliminate many engineering materials that are available. Thus, the nanobiomaterial should possess adequate physical and mechanical properties and surface characteristics to serve as augmentation or replacement of body tissues. This paper discusses classification of different biomaterials and their standards reference in micro- and nano-scale are used in medical engineering applications in details.

scholarly journals Design of equipment for mas-wrestling

2020 ◽  
Vol 164 ◽  
pp. 14005
Author(s):  
Lyubov Zhukova ◽  
Diana Baisheva
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Design Process ◽  
Age Groups ◽  
Physical And Mechanical Properties ◽  
Weight Category ◽  
Mechanical Properties Of Materials ◽  
Properties Of Materials

The present research considers the elaboration of an item of sports equipment – a stick for mas-wrestling. The paper describes the design process of this equipment taking into account physical and mechanical properties and material roughness, as well as sportsmen’s anthropometry parameters according to their weight category. A classification of sportsmen by anthropometry indicators was elaborated, that contains three groups and provides for age groups. The material to produce the equipment for mas-wrestling was chosen based on a comparative analysis of physical and mechanical properties of materials.

Alternative Length Scales for Polycrystalline Materials

1990 ◽  
Vol 209 ◽  
Author(s):  
C.S. Nichols ◽  
R.F. Cook ◽  
D.R. Clarke ◽  
D.A. Smith
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Cluster Size ◽  
Constitutive Relations ◽  
Physical And Mechanical Properties ◽  
Polycrystalline Materials ◽  
Length Scale ◽  
Average Cluster Size ◽  
Average Cluster ◽  
Relevant Length Scale

AbstractIt is well established from studies of bicrystals that the properties of a grain boundary depend on the atomic structure of the boundary. However, constitutive relations for the properties of polycrystalline materials do not currently take into account this boundary-toboundary variability. Instead, such relations depend on a single length scale, typically the average grain diameter. We extend the traditional viewpoint by proposing that boundaries may be divided into two distinct categories, depending on their misorientation angle. The relevant length scale in constitutive relations for polycrystals is then the average cluster size, where clusters consist of grains connected by boundaries in the same misorientation category. A brief discussion of this additional length scale and how it may be reflected in various constitutive relations for physical and mechanical properties of polycrystals is given.

scholarly journals USE OF SHELL-CONTAINING SOIL IN TRANSPORT CONSTRUCTION

2020 ◽  
pp. 8-15
Author(s):  
M. Vysotskaya ◽  
M. Lashin ◽  
A. Kurlykina
Keyword(s):  
Mechanical Properties ◽  
Mechanical Load ◽  
Physical And Mechanical Properties ◽  
Road Construction ◽  
The Body ◽  
Filtration Coefficient ◽  
Construction Sites ◽  
Maximum Increase ◽  
Input Control ◽  
Partial Remainder

The article deals with the problem of using soils represented by sand with a significant content of shell in the construction of embankments of railways and highways. The review of literature sources on this topic did not yield any results, which aroused interest in the possibility of using this soil. Research has been carried out to determine the main physical and mechanical properties of shell sand. Data showing the dynamics of changes in the physical and mechanical properties of the soil during compaction are obtained. The dependence of the reduction of partial residues from 10 to 0.1 sieves is revealed. The maximum increase in the partial remainder occurs on the screen 0,1. Obviously, these changes are the result of grinding the soil under the influence of a large mechanical load and are one of the factors reducing filtration in this soil. It is found that the value of the filtration coefficient at the input control is 2.58 m/day., after compaction of the same soil in the body of the embankment, the filtration coefficient fell to-1.51 m/day. Thus, there is a decrease in the filtration coefficient after compaction of the soil by 41.5% in comparison with the input tests of the soil. The need for further research to find technological solutions for the use of such soil on road construction sites is justified.

Features and types of soils in construction

2021 ◽  
Vol 80 (2) ◽  
pp. 221-228
Author(s):  
E. Imankazy ◽  
◽  
I.N. Dyusembaev ◽  
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Optimal Type

The article discusses the classification of the main types of soils for the construction of the foundation, their properties, variability of physical and mechanical properties, the choice of the optimal type of foundation.

scholarly journals Stress theory for classical fields

2017 ◽  
Vol 25 (7) ◽  
pp. 1472-1503 ◽  
Author(s):  
Raz Kupferman ◽  
Elihu Olami ◽  
Reuven Segev
Keyword(s):  
Continuum Mechanics ◽  
Configuration Space ◽  
Fiber Bundle ◽  
Constitutive Relations ◽  
General Setting ◽  
The Body ◽  
Dimensional Manifold ◽  
Stress Theory ◽  
Infinite Dimensional ◽  
Geometric Setting

Classical field theories, together with the Lagrangian and Eulerian approaches to continuum mechanics, are embraced under a geometric setting of a fiber bundle. The base manifold can be either the body manifold of continuum mechanics, the space manifold, or space–time. Differentiable sections of the fiber bundle represent configurations of the system and the configuration space containing them is given the structure of an infinite-dimensional manifold. Elements of the cotangent bundle of the configuration space are interpreted as generalized forces and a representation theorem implies that there exists a stress object representing forces, non-uniquely. The properties of stresses are studied, as well as the role of constitutive relations in this general setting.

scholarly journals Effect of Dehydrothermal Treatment on the Mechanical Properties and Biocompatibility of Plaster of Paris–CaCO3 Hydrogel Loaded With Cinnamaldehyde for Biomedical Purposes

2021 ◽  
Vol 16 (1) ◽  
pp. 1934578X2098460
Author(s):  
Anne Handrini Dewi ◽  
Dedy Kusuma Yulianto ◽  
Widowati Siswomihardjo ◽  
Rochmadi Rochmadi ◽  
Ika Dewi Ana
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Inflammatory Cells ◽  
The Body ◽  
Chemical Agent ◽  
3 Dimensional ◽  
Plaster Of Paris ◽  
Inflammatory Agent ◽  
Anti Inflammatory

CaCO3 hydrogel incorporation into Plaster of Paris (POP) formulations decreased the resorption rate of the POP after implantation in the body. Although an inflammatory process is required as part of wound healing, the accumulation and activation of inflammatory cells in the POP–hydrogel CaCO3 implant area needs to be controlled. Therefore, cinnamaldehyde, as an anti-inflammatory agent with a unique α, β-unsaturated aldehyde, was incorporated into the CaCO3 hydrogel. During the incorporation, both the lipophilic and hydrophilic sides of the cinnamaldehyde molecule can influence the physical and mechanical properties of the CaCO3 hydrogel, in which mechanical properties of a tissue engineering scaffold are important to fine tune cellular activity during implantation. On the other hand, as a 3-dimensional polymeric structure, crosslinking is needed for the CaCO3 hydrogel to stabilize and increase its molecular weight for better mechanical strength, and more resistance to heat, wear, and solvent attack. For that purpose, dehydrothermal treatment (DHT) was applied to the crosslink hydrogel system as a favorable crosslinking method to avoid the use of a chemical agent. In this study, 3 groups of hydrogels of CaCO3, namely DHT crosslinked, loaded with cinnamaldehyde, and loaded with cinnamaldehyde followed by DHT crosslinking were developed before being combined with POP in 50 wt%. To evaluate the effect of DHT to the final POP-cinnamaldehyde-loaded CaCO3 hydrogel properties and biocompatibility, scanning electron microscopy, contact angle, surface roughness, hardness, diametral tensile strength, and in vivo biocompatibility studies were conducted. It was observed that cinnamaldehyde with DHT treatment improved the POP–hydrogel CaCO3 properties and had good biocompatibility. Thus, POP-cinnamaldehyde-loaded CaCO3 hydrogel can be a promising bone substitute containing an anti-inflammatory agent.

Sign in / Sign up

Export Citation Format

Share Document