Determinism and Stability in Physics

2018 ◽  
pp. 61-81
Author(s):  
Yemima Ben-Menahem
Keyword(s):  
Quantum Mechanics ◽  
Statistical Mechanics ◽  
Chaos Theory ◽  
Physical Sciences ◽  
Stability And Instability ◽  
Conceptual Relations ◽  
The Stability

This chapter examines the role of stability and determinism in physical theories such as statistical mechanics. In the physical sciences, the notions of stability and instability, no longer camouflaged in the language of necessity and contingency, are often used in a variety of contexts, from chaos theory to quantum mechanics. Physicists consider questions about the stability of states, orbits, and structures to be as fundamental as questions about determinism. Before expounding on the conceptual relations between stability and determinism in physics, the chapter discusses three interconnected problems that statistical mechanics has had to tackle: the meaning of probability in statistical mechanics, the link between probability and a system's dynamics, and the origin of directionality. It shows that the notions of determinism and stability are often conflated, giving rise to teleological thinking.

scholarly journals The role of idealisations in describing an isolated molecule

2019 ◽  
Vol 22 (1) ◽  
pp. 15-29
Author(s):  
Vanessa A. Seifert
Keyword(s):  
Quantum Mechanics ◽  
Time Range ◽  
Philosophical Literature ◽  
Thermodynamic Conditions ◽  
The Stability

Abstract The investigation of the relation between chemistry and quantum mechanics includes examining how the two theories each describe an isolated molecule. This paper focuses on one particular characteristic of chemistry’s and quantum mechanics’ descriptions of an isolated molecule; namely on the assumptions made by each description that an isolated molecule is stable and has structure. The paper argues that these assumptions are an idealisation. First, this is because stability and structure are partially determined by factors that concern the context in which a molecule is considered (i.e. thermodynamic conditions, time-range of experiment, environment, etc.). Secondly, the stability and structure of a molecule can only be empirically identified with reference to those factors. This paper examines these assumptions in the context of the philosophical literature on idealisations. This examination is a novel contribution that raises interesting questions about the relation between the two theories, the nature of stability and structure, and the function of these assumptions in the two theories.

The Effects of Collisions with Neutral Particles on the Instability of Two Superposed Composite Plasmas Streaming Through Porous Medium

1999 ◽  
Vol 54 (6-7) ◽  
pp. 411-416 ◽  
Author(s):  
Mohamed Fahmy El-Sayed
Keyword(s):  
Porous Medium ◽  
Unstable Mode ◽  
Instability Criterion ◽  
Stable Configuration ◽  
Neutral Particles ◽  
Fluid Velocities ◽  
Stability And Instability ◽  
The Stability ◽  
The Magnetic Field

Abstract The effects of collisions with neutral atoms on the hydromagnetic stability of the plane interface separating two streaming superposed composite plasmas of uniform densities in a porous medium are investigated. In the absence of fluid velocities, it is found, for a potentially stable configuration, that the system remains stable, while for a potentially unstable configuraion, the unstable system becomes stable under a certain condition of the wavenumber depending on the values of the fluid densities, Alfvén velocities, and the orientation of the magnetic field. The porosity of the porous medium does not have any significant effect on the stability criterion. In the presence of fluid velocities, it is found that, the instability criterion is independent of the permeability of the medium and the collision effects with neutral particles. The criterion determing the stability does not depend on the permeability of the medium but depends on the density of neutral particles. The porosity of the medium is found to have a significant effect on both the stability and instability criteria in this case. The role of the permeability of the medium, the collisional frequency, and the porosity of the porous medium on the growth rate of the unstable mode is examined analitically. Routh’s test of stability is applied to confirm the above results.

scholarly journals The role of calcium ions in the stability and instability of a thermolysin-like protease

2011 ◽  
Vol 20 (8) ◽  
pp. 1346-1355 ◽  
Author(s):  
V. G. H. Eijsink ◽  
B. W. Matthews ◽  
G. Vriend
Keyword(s):  
Calcium Ions ◽  
Stability And Instability ◽  
The Stability

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

An Exercise in a Transdisciplinary Approach for New Knowledge Paradigms

2014 ◽  
Vol 3 (3) ◽  
pp. 114-143
Author(s):  
Gabriel Crumpei ◽  
Maricel Agop ◽  
Alina Gavriluţ ◽  
Irina Crumpei
Keyword(s):  
Quantum Mechanics ◽  
20Th Century ◽  
Chaos Theory ◽  
Fractal Geometry ◽  
Science And Religion ◽  
Transdisciplinary Approach ◽  
Linear Dynamics ◽  
New Knowledge ◽  
Religious Perspectives ◽  
Energy Information

Abstract In this paper, we aim at an exercise that is transdisciplinary, involving science and religion, and interdisciplinary, involving disciplines and theories which appeared in the second half of the 20th century (e.g., topology, chaos theory, fractal geometry, non-linear dynamics, all of which can be found in the theory of complex systems). The latter required the reformulation of quantum mechanics theories starting with the beginning of the century, based on the substance-energy-information triangle. We focus on information and we also attempt a transdisciplinary approach to the imaginary from a psychological - physical - mathematical perspective, but the religious perspectives find their place along with the philosophical or even philological vision

The identity policy and its effect in the stability of Middle East after 2010

2019 ◽  
pp. 434
Author(s):  
Ali Hussein Kadhim Alesammi
Keyword(s):  
Middle East ◽  
International Relations ◽  
Social Construct ◽  
Stability And Instability ◽  
The Social ◽  
The Stability ◽  
International Interactions ◽  
Regional Interests ◽  
Political Groups ◽  
Identity Policy

Since 2010 Middle East have many events or what they call "Arab spring events" which it result of overthrow governments and the rise of new political groups, all of this elements was resulting of many international and regional activities and making new regional and international axles, as well as the intersections of the different regional interests, therefore this research will try to study the stability and instability in the region as an independent variable not according to the neorealism or neoliberalism theories, but according to the constructivism theory which it base their assumptions on:  "In the international relations the non-physical structures of international interactions are determined by the identities of the players, which in turn determine the interests that determine the behavior of international players." So the research questions are: 1-What is the identity policy and haw affect in international relations? 2-How the social construct affect in international relations? 3-How the elite's identities for the main actors in the Middle East affect in the regional axles?  

The Role of Hydrophobicity in the Stability and pH-Switchability of (RXDX)4 and Coumarin-RXDX Conjugate β-Sheets

2020 ◽  
Author(s):  
Ryan Weber ◽  
Martin McCullagh
Keyword(s):  
Biological Imaging ◽  
Ph Sensing ◽  
Hydrophobic Residue ◽  
Ideal Candidate ◽  
Self Assembling ◽  
Sensing Applications ◽  
Β Sheets ◽  
The Stability ◽  
Dynamics Simulations

<p>pH-switchable, self-assembling materials are of interest in biological imaging and sensing applications. Here we propose that combining the pH-switchability of RXDX (X=Ala, Val, Leu, Ile, Phe) peptides and the optical properties of coumarin creates an ideal candidate for these materials. This suggestion is tested with a thorough set of all-atom molecular dynamics simulations. We first investigate the dependence of pH-switchabiliy on the identity of the hydrophobic residue, X, in the bare (RXDX)<sub>4</sub> systems. Increasing the hydrophobicity stabilizes the fiber which, in turn, reduces the pH-switchabilty of the system. This behavior is found to be somewhat transferable to systems in which a single hydrophobic residue is replaced with a coumarin containing amino acid. In this case, conjugates with X=Ala are found to be unstable and both pHs while conjugates with X=Val, Leu, Ile and Phe are found to form stable β-sheets at least at neutral pH. The (RFDF)<sub>4</sub>-coumarin conjugate is found to have the largest relative entropy value of 0.884 +/- 0.001 between neutral and acidic coumarin ordering distributions. Thus, we posit that coumarin-(RFDF)<sub>4</sub> containing peptide sequences are ideal candidates for pH-sensing bioelectronic materials.</p>

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