New Results in Dynamics Stability Problems of Elastic Rods

2014 ◽  
Vol 617 ◽  
pp. 181-186 ◽  
Author(s):  
Vladimir Vladimirovich Lalin ◽  
Daria Aleksandrovna Kushova
Keyword(s):  
Elastic Rods ◽  
Geometrically Nonlinear ◽  
Cosserat Theory ◽  
Stability Problems ◽  
New Exact Solutions ◽  
Longitudinal Stiffness ◽  
Different Types ◽  
The Stability ◽  
Nonlinear Dynamic Stability ◽  
Dynamics Stability

This article is about the nonlinear dynamic stability problems of the exact (Cosserat) theory of elastic rods. There is examined the general geometrically nonlinear theory with no restrictions on displacements and rotations being imposed. In this article, it is shown that the variational problem can be defined as the search for the stationary point of the Hamilton’s functional. The new exact solutions of the stability problems for different types of the end fixities of the rod were obtained taking into account bending, shear and longitudinal stiffness.

Stability and Vibrations of Geometrically Nonlinear Cylindrically Orthotropic Circular Plates

1984 ◽  
Vol 51 (2) ◽  
pp. 354-360 ◽  
Author(s):  
D. Shilkrut
Keyword(s):  
Stability Analysis ◽  
Qualitative Methods ◽  
Dynamic Method ◽  
Numerical Results ◽  
Geometrically Nonlinear ◽  
Circular Plates ◽  
Different Types ◽  
The Stability ◽  
Thermal Influence ◽  
Cylindrically Orthotropic

The stability analysis of axisymmetrical equilibrium states of geometrically nonlinear, orthotropic, circular plates that are deformed by multiparameter loading, including thermal influence, is presented. The dynamic method (method of small vibrations) is used to accomplish this purpose. The behavior of the plate in different cases is revealed. In particular, it is shown that two different types of snapping processes can occur. The values of frequencies of small eigenvibrations from various cases have been calculated. These investigations are realized by numerical and qualitative methods. Here only the numerical results are presented.

scholarly journals Slope Stability Problems Along the Main Roads in the Kurdistan Region

2018 ◽  
Vol 7 (4) ◽  
pp. 197
Author(s):  
Varoujan K. Sissakian ◽  
Hassan O. Omer
Keyword(s):  
Slope Stability ◽  
Winter Season ◽  
Road Construction ◽  
Heavy Rain ◽  
Modern Technology ◽  
Kurdistan Region ◽  
Stability Problems ◽  
Geological Conditions ◽  
Different Types ◽  
The Stability

The Kurdistan Region is covered by the relevant net of roads. Since the major parts of the Kurdistan Region are mountainous; therefore, the majority of them are in snake curve form. Construction of roads in mountainous areas will destroy the natural slopes, and when not treated; then different types of landslides will occur. Accordingly, the unstable slopes will cause a lot of risk to the traffic along the roads; endangering the driving along those roads; especially during winter season, and during and/ or shortly after heavy rain showers. The majority of the roads in the Kurdistan Region are planned, designed and constructed without considering the geological conditions, which include four parameters: 1) Type of the rocks and soils, 2) Dip direction and amount, 3) Intensity of joint planes, and 4) Weathering grade of the rocks. These are not considered due to: 1) Cost, 2) Construction’s duration, 3) Choosing easier paths, 4) Absence of experience, 5) Absence of modern technology, 6) Absence of road construction codes, and 7) Ignorance of the factor of safety. We studied different examples from roads in the Kurdistan Region and presented different types of slope stability problems. Moreover, we presented recommendations to keep the stability along unstable slopes.

ASSESSMENT OF PINE CROPS GROWTH IN BAIMAK FORESTRY

2020 ◽  
Vol 37 (3) ◽  
pp. 83-90
Author(s):  
T.Z. Mutallapov ◽  
Keyword(s):  
Scots Pine ◽  
Forest Ecosystem ◽  
Distribution Curve ◽  
Comparative Assessment ◽  
Tree Distribution ◽  
Entire Structure ◽  
Structure Changes ◽  
Large Trees ◽  
Different Types ◽  
The Stability

The article presents the results of evaluating the growth of Scots pine in the Baymak forest area. The analysis of forestry and taxation indicators of Scots pine crops on the studied sample areas is carried out, and a comparative assessment of the growth of forest crops growing in different types of forest is given. Increased competition in plantings leads to the natural decline of stunted trees, which is the result of differentiation in the stand. As a result, its structure changes, the number of large trees increases, and, accordingly, the stability of the forest ecosystem increases. In this regard, the appearance of the tree distribution curve by thickness levels also changes. It becomes more "flat", and its competitive load is more evenly distributed over the entire structure of the stand, and competition is weakened.

A Survey on Computational Methods for Essential Proteins and Genes Prediction

2019 ◽  
Vol 14 (3) ◽  
pp. 211-225 ◽  
Author(s):  
Ming Fang ◽  
Xiujuan Lei ◽  
Ling Guo
Keyword(s):  
Computational Methods ◽  
Drug Targets ◽  
Disease Genes ◽  
Essential Proteins ◽  
Experimental Identification ◽  
Cellular Life ◽  
Different Types ◽  
The Stability ◽  
Human Disease Genes ◽  
Biology Research

Background: Essential proteins play important roles in the survival or reproduction of an organism and support the stability of the system. Essential proteins are the minimum set of proteins absolutely required to maintain a living cell. The identification of essential proteins is a very important topic not only for a better comprehension of the minimal requirements for cellular life, but also for a more efficient discovery of the human disease genes and drug targets. Traditionally, as the experimental identification of essential proteins is complex, it usually requires great time and expense. With the cumulation of high-throughput experimental data, many computational methods that make useful complements to experimental methods have been proposed to identify essential proteins. In addition, the ability to rapidly and precisely identify essential proteins is of great significance for discovering disease genes and drug design, and has great potential for applications in basic and synthetic biology research. Objective: The aim of this paper is to provide a review on the identification of essential proteins and genes focusing on the current developments of different types of computational methods, point out some progress and limitations of existing methods, and the challenges and directions for further research are discussed.

Numerical exploration on snap buckling of a pre-stressed hemispherical gridshell

2021 ◽  
pp. 1-11
Author(s):  
Weicheng Huang ◽  
Longhui Qin ◽  
Qiang Chen
Keyword(s):  
Three Dimensional ◽  
Energy Functional ◽  
Elastic Rods ◽  
Geometrically Nonlinear ◽  
Local Response ◽  
Micro Electro Mechanical Systems ◽  
One Dimensional ◽  
Numerical Exploration ◽  
Planar Grid ◽  
Fundamental Understanding

Abstract Motivated by the observations of snap-through phenomena in pre-stressed strips and curved shells, we numerically investigate the snapping of a pre-buckled hemispherical gridshell under apex load indentation. Our experimentally validated numerical framework on elastic gridshell simulation combines two components: (i) Discrete Elastic Rods method, for the geometrically nonlinear description of one dimensional rods; and (ii) a naive penalty-based energy functional, to perform the non-deviation condition between two rods at joint. An initially planar grid of slender rods can be actuated into a three dimensional hemispherical shape by loading its extremities through a prescribed path, known as buckling induced assembly; next, this pre-buckled structure can suddenly change its bending direction at some threshold points when compressing its apex to the other side. We find that the hemispherical gridshell can undergo snap-through buckling through two different paths based on two different apex loading conditions. The first critical snap-through point slightly increases as the number of rods in gridshell structure becomes denser, which emphasizes the mechanically nonlocal property in hollow grids, in contrast to the local response of continuum shells. The findings may bridge the gap among rods, grids, knits, and shells, for a fundamental understanding of a group of thin elastic structures, and inspire the design of novel micro-electro-mechanical systems and functional metamaterials.

scholarly journals A General Theorem on the Stability of a Class of Functional Equations Including Quartic-Cubic-Quadratic-Additive Equations

Mathematics ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 282
Author(s):  
Yang-Hi Lee ◽  
Soon-Mo Jung
Keyword(s):  
Functional Equations ◽  
Direct Method ◽  
General Theorem ◽  
Stability Problems ◽  
General Stability ◽  
Stability Theorems ◽  
Additive Type ◽  
The Stability

We prove general stability theorems for n-dimensional quartic-cubic-quadratic-additive type functional equations of the form by applying the direct method. These stability theorems can save us the trouble of proving the stability of relevant solutions repeatedly appearing in the stability problems for various functional equations.

scholarly journals Novel thick brane solutions with U(1) symmetry breaking

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
Marzieh Peyravi ◽  
Nematollah Riazi ◽  
Francisco S. N. Lobo
Keyword(s):  
Symmetry Breaking ◽  
Scalar Fields ◽  
Einstein Tensor ◽  
Vacuum Structure ◽  
Different Types ◽  
Dimensional Gravity ◽  
Breaking Parameter ◽  
Symmetry Breaking Term ◽  
The Stability ◽  
Breaking Term

AbstractIn this work, using two scalar fields ($$\phi $$ ϕ , $$\psi $$ ψ ) coupled to 4 + 1 dimensional gravity, we construct novel topological brane solutions through an explicit U(1) symmetry breaking term. The potential of this model is constructed so that two distinct degenerate vacua in the $$\phi $$ ϕ field exist, in analogy to the $$\phi ^{4}$$ ϕ 4 potential. Therefore, brane solutions appear due to the vacuum structure of the $$\phi $$ ϕ field. However, the topology and vacuum structure in the $$\psi $$ ψ direction depends on the symmetry breaking parameter $$\beta ^{2}$$ β 2 , which leads to different types of branes. As a result, one can interpret the present model as a combination of a $$\phi ^{4}$$ ϕ 4 brane with an auxiliary field, which leads to deviations from the $$\phi ^{4}$$ ϕ 4 system with the brane achieving a richer internal structure. Furthermore, we analyse in detail the behaviour of the superpotentials, the warp factors, the Ricci and Kretschmann scalars and the Einstein tensor components. In addition to this, we explore the stability of the brane in terms of the free parameters of the model. The analysis presented here complements previous work and is sufficiently novel to be interesting.

Fading Time Study on Prepared Thymolphthalein, Phenolphthalein and their Mixture Disappearing Ink

2008 ◽  
Vol 12 (1) ◽  
pp. 9-18
Author(s):  
S.A. Shama ◽  
M.M. El-Molla ◽  
Riad F. Basalah ◽  
S. El-Sayed Saeed
Keyword(s):  
Thermal Effect ◽  
Time Study ◽  
High Concentration ◽  
Different Types ◽  
The Stability ◽  
Fading Time

Disappearing ink was prepared using different concentrations of thymolphthalein, phenolphthalein and their mixture, applying to different types of handwriting surfaces such as cotton, polyester and polyamide. The effects of thymolphthalein, phenolphthalein and alkali concentrations (i.e. pH) on the fading time were studied. The handwriting stability increased when the concentration of thymolphthalein or phenolphthalein was increased. At a high concentration of alkali with phenolphthalein and its mixture with thymolphthalein, the handwriting stability decreased with polyester or polyamide handwriting surfaces and the stability increased in the case of cotton. When the faded handwriting surfaces were subject to the thermal effect in a thermostatically controlled oven at 100°C for 10 minutes by hanging them with suitable hooks, there was no change in the faded handwriting. When they were at 150°C for 20 minutes, the faded phenolphthalein ink, which contained 0.5ml of 1N NaOH, was visible and shown red on the polyester and polyamide handwriting surfaces, but there was no change on the faded cotton handwriting surface.

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