A clearer approach for defining unit systems

  title={A clearer approach for defining unit systems},
  author={Paul Quincey and Richard J.C. Brown},
  pages={454 - 460}
We present the SI and other unit systems, including cgs-em and cgs-es, in a framework whereby a system of fully independent and dimensionally orthogonal base units is modified by conventions designed to simplify the equations that are used within each system. We propose that the radian can be seen as an independent unit whose dimensional status is modified in the SI and other unit systems for this purpose. This framework clarifies how different unit systems are interrelated, and identifies the… 

The role of unit systems in expressing and testing the laws of nature

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On the status of plane and solid angles in the International System of Units (SI)

The article analyzes the arguments that have become the basis for the 1980 CIPM recommendations declaring plane and solid angles as dimensionless derived quantities. This decision was the result of

A metrological approach to quantities that are counted and the unit one

There has long been debate over how to treat dimensionless quantities, or quantities with the unit one, within the International System of Units (SI). These arguments have been brought into sharper

Angles are inherently neither length ratios nor dimensionless

The status of angles within The International System of Units (SI) has long been a source of controversy and confusion. We address one specific but crucial issue, putting the case that the idea of

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  • B. Hall
  • Physics
    2020 IEEE International Workshop on Metrology for Industry 4.0 & IoT
  • 2020
A Python package is presented that allows a measured value to be paired with a measurement unit (scale), in an entity that can be used in mathematical operations, and appears to be more powerful than systems designed to work directly with measurement units.

True versus apparent shapes of bow shocks

Astrophysical bow shocks are a common result of the interaction between two supersonic plasma flows, such as winds or jets from stars or active galaxies, or streams due to the relative motion between

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  • Education
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Dimensionless units in the SI

The International System of Units (SI) is supposed to be coherent. That is, when a combination of units is replaced by an equivalent unit, there is no additional numerical factor. Here we consider

Natural units in physics, and the curious case of the radian

Sets of natural units, like ‘atomic units’, are sometimes used to simplify the equations of physics. This choice of units can be seen as a way of showing the relationships between quantities in their

Implications of adopting plane angle as a base quantity in the SI

The treatment of angles within the SI is anomalous compared with other quantities, and there is a case for removing this anomaly by declaring plane angle to be an additional base quantity within the

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This column focuses on Giovanni Giorgi (Figure 1), the Italian scientist who clarified the necessity to augment the existing system of three fundamental units to a fourth electrical one, leading to

Angles-Let's treat them squarely

We suggest a self-consistent treatment of the dimensions and units of the geometric quantity “angle.” The method regards “angle” as a fundamental dimensional physical quantity, on a par with length,

How fundamental are fundamental constants?

  • M. Duff
  • Physics
    Contemporary Physics
  • 2014
I argue that the laws of physics should be independent of one’s choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine

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In this opening paper, a short biography of Rankin is provided and some of his major contributions to mathematics are discussed.

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