The fundamental constants and theory

2005 ◽  
Vol 363 (1834) ◽  
pp. 2123-2137 ◽  
Author(s):  
Peter J Mohr
Keyword(s):  
Experimental Data ◽  
Least Squares ◽  
Science And Technology ◽  
Fundamental Constants ◽  
Conversion Factors ◽  
Self Consistent ◽  
Theoretical Predictions

The Committee on Data for Science and Technology has recently recommended a new self-consistent set of values of basic constants and conversion factors of physics and chemistry. These values are based on a least-squares analysis that takes into account all of the latest relevant experimental and theoretical information in a consistent framework. Theory plays a role, because the experimental data are compared to the corresponding theoretical predictions which are functions of the fundamental constants. The best values of the constants are taken to be those that give the best agreement between the data and these predictions, in the least-squares sense. An overview of the calculations that influence the recommended values of the constants will be given.

The determination of best values of the fundamental physical constants

2005 ◽  
Vol 363 (1834) ◽  
pp. 2105-2122 ◽  
Author(s):  
Barry N Taylor
Keyword(s):  
Least Squares ◽  
Science And Technology ◽  
Fundamental Constants ◽  
Fundamental Physical Constants ◽  
Physical Constants ◽  
Self Consistent ◽  
Modern Physics ◽  
Least Squares Adjustment ◽  
Fundamental Physical

The purpose of this paper is to provide an overview of how a self-consistent set of ‘best values’ of the fundamental physical constants for use worldwide by all of science and technology is obtained from all of the relevant data available at a given point in time. The basis of the discussion is the 2002 Committee on Data for Science and Technology (CODATA) least-squares adjustment of the values of the constants, the most recent such study available, which was carried out under the auspices of the CODATA Task group on fundamental constants. A detailed description of the 2002 CODATA adjustment, which took into account all relevant data available by 31 December 2002, plus selected data that became available by Fall of 2003, may be found in the January 2005 issue of the Reviews of Modern Physics . Although the latter publication includes the full set of CODATA recommended values of the fundamental constants resulting from the 2002 adjustment, the set is also available electronically at http://physics.nist.gov/constants .

Momentum distribution and the universal contact of a unitary Fermi gas with particle-hole fluctuation

2018 ◽  
Vol 32 (21) ◽  
pp. 1850249 ◽  
Author(s):  
Xiao-Xia Ruan ◽  
Hao Gong ◽  
Zheng-Ling Wang ◽  
Hong-Shi Zong
Keyword(s):  
Experimental Data ◽  
Momentum Distribution ◽  
Fermi Gas ◽  
Normal Phase ◽  
Large Momentum ◽  
Matrix Approximation ◽  
Self Consistent ◽  
Theoretical Predictions ◽  
Unitary Fermi Gas ◽  
T Matrix

We compute the momentum distribution of a homogeneous Fermi gas at unitarity in the normal phase within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. From the large-momentum behavior of momentum distribution, we obtain the contact for the unitary Fermi gas. We also compare our results with experimental data and other theoretical predictions.

scholarly journals Recommending a value for the Newtonian gravitational constant

2014 ◽  
Vol 372 (2026) ◽  
pp. 20140029 ◽  
Author(s):  
Barry M. Wood
Keyword(s):  
Gravitational Constant ◽  
Present Situation ◽  
Primary Objective ◽  
Experimental Results ◽  
Task Group ◽  
Fundamental Constants ◽  
Conversion Factors ◽  
A Value ◽  
Self Consistent ◽  
Newtonian Gravitational Constant

The primary objective of the CODATA Task Group on Fundamental Constants is ‘to periodically provide the scientific and technological communities with a self-consistent set of internationally recommended values of the basic constants and conversion factors of physics and chemistry based on all of the relevant data available at a given point in time’. I discuss why the availability of these recommended values is important and how it simplifies and improves science. I outline the process of determining the recommended values and introduce the principles that are used to deal with discrepant results. In particular, I discuss the specific challenges posed by the present situation of gravitational constant experimental results and how these principles were applied to the most recent 2010 recommended value. Finally, I speculate about what may be expected for the next recommended value of the gravitational constant scheduled for evaluation in 2014.

scholarly journals An Additive Model to Predict the Rheological and Mechanical Properties of Polypropylene Blends Made by Virgin and Reprocessed Components

Recycling ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Francesco Paolo La Mantia ◽  
Maria Chiara Mistretta ◽  
Vincenzo Titone
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Additive Model ◽  
Industrial Process ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Polypropylene Blends ◽  
Polypropylene Sample

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.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Evolution of the peroxide-induced degradation of polypropylene along a twin-screw extruder: Experimental data and theoretical predictions

2005 ◽  
Vol 99 (5) ◽  
pp. 2082-2090 ◽  
Author(s):  
F. Berzin ◽  
B. Vergnes ◽  
S. V. Canevarolo ◽  
A. V. Machado ◽  
J. A. Covas
Keyword(s):  
Experimental Data ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Theoretical Predictions ◽  
Twin Screw

scholarly journals Determination of parameters for Cauchy’s problem for systems of ODEs with application to biological modelling

BIOMATH ◽  
2016 ◽  
Vol 5 (1) ◽  
pp. 1604231
Author(s):  
A.N. Pete ◽  
Peter Mathye ◽  
Igor Fedotov ◽  
Michael Shatalov
Keyword(s):  
Experimental Data ◽  
Mathematical Models ◽  
Least Squares ◽  
Numerical Method ◽  
Least Squares Method ◽  
Algebraic Equations ◽  
Systems Of Odes ◽  
Determination Of Parameters ◽  
Biological Modelling

An inverse numerical method that estimate parameters of dynamic mathematical models given some information about unknown trajectories at some time is applied to examples taken from Biology and Ecology. The method consisting of determining an over-determined system of algebraic equations using experimental data. The solution of the over-determined system is then obtained using, for example the least-squares method. To illustrate the effectiveness of the method an analysis of examples and corresponding numerical example are presented.

scholarly journals Gravity cells as a necessary link in string theory. The formula for the gravitational constant, the formula for the mass of the electron, the formula for the minimum distance of the gravitational interaction. The coincidence of the results obtained by the formulas and the experimental data.

2021 ◽  
Author(s):  
Andrey Chernov
Keyword(s):  
Experimental Data ◽  
Black Holes ◽  
String Theory ◽  
Minimum Distance ◽  
Gravitational Constant ◽  
Casimir Effect ◽  
Gravitational Interaction ◽  
Fundamental Constants ◽  
Vibrational Velocity ◽  
Schwarzschild Radius

Abstract In this study, a new concept is introduced into physics - gravitational cells. The gravitational cell hypothesis was organically integrated into string theory. As a result, using the Schwarzschild radius formula and the Coulomb formula, a gravitational formula in the region of black holes was obtained on the basis of two fundamental constants, and its exact value was determined. The value of the "usual" gravitational constant was also confirmed and the mass of the gravitational cell was obtained. The introduction of the hypothesis of gravitational cells into string theory made it possible to apply Planck's formula to gravitational interaction. As a result, a formula for the energy of a gravitational quantum and a formula for the vibrational velocity of a gravitational string were obtained. On this basis, the formula for the mass of the electron was obtained and its value was calculated, which coincided with the experimental mass of the electron. The exact minimum distance of the gravitational interaction was determined by the formula for the vibrational velocity of the gravitational string. This calculated minimum distance completely coincided with the known experimental data obtained when determining the Casimir effect (force).

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