Hydraulic fluid power – Interpolation method for particle count and filter test data

This document describes a recommended method for the interpolation of particle concentration and filter Beta Ratio data when results are not otherwise available at the desired particle sizes. It is applicable for assessing conformance with existing fluid cleanliness and filter Beta Ratio specifications whereby the specification and actual test results are provided in different units of particle size, for example, the specification is in µm(c), but the particle counts or Beta Ratio data are in units of µm(b). This document is also applicable when particle sizes in specifications and available data use the same units of particle size, but do not correspond to exactly the same sizes, for example, when particle counts at 20 µm(c) are specified, but data was collected at 21 µm(c). This method allows interpolation to intermediate particle sizes within the range of existing data and does not permit extrapolation to particle sizes outside the range of available data.

Transmissions hydrauliques – Méthode d'interpolation pour les données issues du comptage des particules et des essais du filtre

General Information

Status
Published
Publication Date
15-Feb-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
14-Jan-2021
Completion Date
14-Jan-2021
Ref Project

Buy Standard

Technical report
ISO/TR 4808:2021 - Hydraulic fluid power – Interpolation method for particle count and filter test data
English language
12 pages
sale 15% off
Preview
sale 15% off
Preview
Draft
ISO/PRF TR 4808:Version 26-dec-2020 - Hydraulic fluid power – Interpolation method for particle count and filter test data
English language
11 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

TECHNICAL ISO/TR
REPORT 4808
First edition
2021-02
Hydraulic fluid power – Interpolation
method for particle count and filter
test data
Transmissions hydrauliques – Méthode d'interpolation pour les
données issues du comptage des particules et des essais du filtre
Reference number
ISO/TR 4808:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO/TR 4808:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 4808:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Background ................................................................................................................................................................................................................ 1

5 Interpolation of particle concentration and Beta Ratio data ................................................................................. 3

6 Example of interpolation of particle concentration data ........................................................................................... 4

7 Example of interpolation of filter Beta Ratio and removal efficiency data .............................................6

8 Summary ....................................................................................................................................................................................................................10

BIBLIOGRAPHY ......................................................................................................................................................................................................................12

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TR 4808:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 6, Contamination control.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 4808:2021(E)
Introduction

The 2016 version of ISO 11171 provides options for reporting particle size in either units of µm(c) or

µm(b). While mathematical conversion of µm(b) sizes to µm(c) sizes is straightforward, there is no

such universal means for converting particle concentrations or filter Beta Ratios. This is problematic

when attempting to comply with contamination control and filter performance specifications given in

integral units of µm(c) when data are in integral units of µm(b) corresponding to decimal point µm(c)

sizes, or vice versa. For example, particle sizes of 4 µm(b), 6 µm(b), 14 µm(b) and 21 µm(b), correspond

to sizes of 3,6 µm(c), 5,4 µm(c), 12,6 µm(c) and 18,9 µm(c), respectively. In the absence of a common

interpolation method, otherwise acceptable fluid and filter products can be deemed unacceptable for

use because of a discrepancy in the particle sizes reported. This document describes a recommended

method for converting µm(b) data to µm(c) data and for interpolating particle concentration, Beta

Ratio, and removal efficiency data. The resultant interpolated values can be used to convert cleanliness

level or filter performance specifications and data from µm(b) to µm(c).
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 4808:2021(E)
Hydraulic fluid power – Interpolation method for particle
count and filter test data
1 Scope

This document describes a recommended method for the interpolation of particle concentration

and filter Beta Ratio data when results are not otherwise available at the desired particle sizes. It is

applicable for assessing conformance with existing fluid cleanliness and filter Beta Ratio specifications

whereby the specification and actual test results are provided in different units of particle size, for

example, the specification is in µm(c), but the particle counts or Beta Ratio data are in units of µm(b).

This document is also applicable when particle sizes in specifications and available data use the same

units of particle size, but do not correspond to exactly the same sizes, for example, when particle

counts at 20 µm(c) are specified, but data was collected at 21 µm(c). This method allows interpolation

to intermediate particle sizes within the range of existing data and does not permit extrapolation to

particle sizes outside the range of available data.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 4406, Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles

ISO 11171, Hydraulic fluid power — Calibration of automatic particle counters for liquids

ISO 16889, Hydraulic fluid power — Filters — Multi-pass method for evaluating filtration performance of

a filter element
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4406, ISO 11171 and

ISO 16889 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Background

In contamination control programmes, filter purchase decisions and quality control programmes,

particle count and filter Beta Ratio data are compared to established benchmarks, such as fluid

cleanliness specifications, filter performance specifications and historical data. Meaningful assessments

can only be made if identical sizes are being compared. This became an issue with ISO 11171:2016.

Historical data and specifications prior to 2016 were reported in size units of µm(c). Beginning in 2016,

however, some chose to report size in units of µm(b) while others report in µm(c). The two units of

particle size, µm(c) and µm(b), are mathematically related, but the corresponding values for particle

concentration and Beta Ratio are not. The 10 % difference in particle size between the two units of

particle size yields differences in the corresponding particle concentrations and Beta Ratios. These, in

turn, can significantly impact critical contamination control decisions.
© ISO 2021 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/TR 4808:2021(E)

As an example, consider whether or not to replace the oil in a hypothetical hydraulic system. In this

example, it is assumed that the cleanliness level specification for its hydraulic fluid is an ISO 4406

code of 18/17/13. When a sample of the fluid was analyzed, particle concentrations of 5 135 particles/

mL, 1 368 particles/mL, 98,3 particles/mL and 19,5 particles/mL at 4 µm(b), 6 µm(b), 14 µm(b), and

21 µm(b) respectively, were reported. Does this fluid meet the cleanliness specification, in which case

it can continue to be used, or it is contaminated and must be replaced, and the corresponding costs of

new fluid, downtime and lost productivity incurred? An uninformed user can incorrectly convert these

µm(b) concentrations to ISO code values of 20/18/14 and conclude that the fluid was contaminated.

This would be an expensive mistake. ISO 4406 stipulates that the code applies to particle sizes of 4

µm(c), 6 µm(c) and 14 µm(c), not µm(b). Particle sizes of 4 µm(b), 6 µm(b), 14 µm(b) and 21 µm(b) sizes

correspond to 3,6 µm(c), 5,4 µm(c), 12,6 µm(c) and 18,9 µm(c), respectively. The µm(b) concentrations

appear higher than those concentrations found for µm(c) sizes of the same numerical value. Ideally,

the sample should be re-analyzed using an Automatic Particle Counter (APC) calibrated in µm(c), but

this is often impossible or impractical. A similar problem occurs whenever specifications and data (e.g.

particle concentrations, ISO codes, or filter Beta Ratios) are in different units of particle size. Thus,

there is a need for a reliable method for converting µm(b) to µm(c), and then for interpolating to obtain

data at the desired particle sizes for contamination control decisions.

The constrained cubic spline method of interpolation that is used in ISO 11171:2020 to relate particle

concentrations to threshold settings and particle sizes to create calibration curves for APCs, may

be used to interpolate particle concentration and filter Beta Ratio data. Traditional cubic spline

interpolation starts with a series of known data points, the training data set, and interpolates between

them according to the following rules:
— The cubic spline curve passes through all of the known points;
— The curve connecting consecutive points are a third-degree polynomial;
— The first derivative of the curves on each side of a known point are equal;

— The second derivative of the curves on each side of a known point are equal; and

— Boundary conditions are established for the minimum and maximum values of x.

While traditional cubic spline interpolation produces a smooth curve, its usefulness for purposes of

interpolating particle concentration and Beta Ratio data is compromised by a tendency to overshoot

between node points. In contrast, the constrained cubic spline method prevents overshooting and

improves accuracy by sacrificing a little in terms of smoothness. This is accomplished by eliminating

the requirement for second derivatives to be equal. Instead, the first order derivatives on each side of a

point are specified. Since accuracy is paramount in particle counter calibration, the constrained cubic

spline method has been adopted in ISO 11171:2020. The same rationale applies to other fluid power

cleanliness and filter performance applications.

Contamination control decisions should be made using data obtained at the actual sizes defined in

specifications or standards, but this is not always possible or practical. For example, a standard can

specify particle size in units of µm(c), but the available particle count or Beta Ratio data can be from

an APC calibrated to ISO 11171:2016 and reported size in units of µm(b). Similarly, a specification can

use µm(b) sizes from the obsolete ISO 11171:2016, but the available data can be from an APC calibrated

to ISO 11171:2020 which reports size only in units of µm(c). In such cases, the constrained cubic spline

method of interpolation is recommended for estimating particle concentrations and Beta Ratios as a

function of particle size, when data is not available at the specific sizes of interest. It should be noted

that the accuracy of the resultant interpolation is dependent upon the quality of the original data.

Accuracy is sacrificed when the input data contains errors, when there is too little data available for

accurate interpolation, or when the available sizes skew the interpolation.
2 © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 4808:2021(E)
5 Interpolation of particle concentration and Beta Ratio data

Meaningful comparisons of particle concentrations and Beta Ratios can only be made if all data is

reported in the same units of particle size. ISO 11171:2020 standardized on µm(c) as the only acceptable

unit for reporting particle size; hence it is recommended that specifications and historical data utilizing

µm(b) sizes be converted to their corresponding µm(c) sizes. The interpolation of µm(b) to µm(c) data

involves the following steps:
1) Mathematical convers
...

TECHNICAL ISO/TR
REPORT 4808
First edition
Hydraulic fluid power – Interpolation
method for particle count and filter
test data
Transmissions hydrauliques – Méthode d'interpolation pour les
données issues du comptage des particules et des essais du filtre
PROOF/ÉPREUVE
Reference number
ISO/TR 4808:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO/TR 4808:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 4808:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Background ................................................................................................................................................................................................................ 1

5 Interpolation of particle concentration and Beta Ratio data ................................................................................. 3

6 Example of interpolation of particle concentration data ........................................................................................... 4

7 Example of interpolation of filter Beta Ratio and removal efficiency data .............................................6

8 Summary ....................................................................................................................................................................................................................... 9

BIBLIOGRAPHY ......................................................................................................................................................................................................................11

© ISO 2020 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO/TR 4808:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 6, Contamination control.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 4808:2020(E)
Introduction

The 2016 version of ISO 11171 provides options for reporting particle size in either units of µm(c) or

µm(b). While mathematical conversion of µm(b) sizes to µm(c) sizes is straightforward, there is no

such universal means for converting particle concentrations or filter Beta Ratios. This is problematic

when attempting to comply with contamination control and filter performance specifications given in

integral units of µm(c) when data are in integral units of µm(b) corresponding to decimal point µm(c)

sizes, or vice versa. For example, particle sizes of 4 µm(b), 6 µm(b), 14 µm(b) and 21 µm(b), correspond

to sizes of 3,6 µm(c), 5,4 µm(c), 12,6 µm(c) and 18,9 µm(c), respectively. In the absence of a common

interpolation method, otherwise acceptable fluid and filter products can be deemed unacceptable for

use because of a discrepancy in the particle sizes reported. This document describes a recommended

method for converting µm(b) data to µm(c) data and for interpolating particle concentration, Beta

Ratio, and removal efficiency data. The resultant interpolated values can be used to convert cleanliness

level or filter performance specifications and data from µm(b) to µm(c).
© ISO 2020 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 4808:2020(E)
Hydraulic fluid power – Interpolation method for particle
count and filter test data
1 Scope

This document describes a recommended method for the interpolation of particle concentration

and filter Beta Ratio data when results are not otherwise available at the desired particle sizes. It is

applicable for assessing conformance with existing fluid cleanliness and filter Beta Ratio specifications

whereby the specification and actual test results are provided in different units of particle size, for

example, the specification is in µm(c), but the particle counts or Beta Ratio data are in units of µm(b).

This document is also applicable when particle sizes in specifications and available data use the same

units of particle size, but do not correspond to exactly the same sizes, for example, when particle

counts at 20 µm(c) are specified, but data was collected at 21 µm(c). This method allows interpolation

to intermediate particle sizes within the range of existing data and does not permit extrapolation to

particle sizes outside the range of available data.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 4406, Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles

ISO 11171, Hydraulic fluid power — Calibration of automatic particle counters for liquids

ISO 16889, Hydraulic fluid power — Filters — Multi-pass method for evaluating filtration performance of

a filter element
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4406, ISO 11171 and

ISO 16889 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Background

In contamination control programmes, filter purchase decisions and quality control programmes,

particle count and filter Beta Ratio data are compared to established benchmarks, such as fluid

cleanliness specifications, filter performance specifications and historical data.

Meaningful assessments can only be made if identical sizes are being compared. This became an issue

with ISO 11171:2016. Historical data and specifications prior to 2016 were reported in size units of

µm(c). Beginning in 2016, however, some chose to report size in units of µm(b) while others report in

µm(c). The two units of particle size, µm(c) and µm(b), are mathematically related, but the corresponding

values for particle concentration and Beta Ratio are not. The 10 % difference in particle size between

the two units of particle size yields differences in the corresponding particle concentrations and Beta

Ratios. These, in turn, can significantly impact critical contamination control decisions.

© ISO 2020 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 6 ----------------------
ISO/TR 4808:2020(E)

As an example, consider whether or not to replace the oil in a hypothetical hydraulic system. In this

example, it is assumed that the cleanliness level specification for its hydraulic fluid is an ISO 4406 code

of 18/17/13. When a sample of the fluid was analyzed, particle concentrations of 5 135 particles/mL, 1

368 particles/mL, 98,3 particles/mL and 19,5 particles/mL at 4 µm(b), 6 µm(b), 14 µm(b), and 21 µm(b)

respectively, were reported. Does this fluid meet the cleanliness specification, in which case it can

continue to be used, or it is contaminated and must be replaced, and the corresponding costs of new

fluid, downtime and lost productivity incurred?

An uninformed user can incorrectly convert these µm(b) concentrations to ISO code values of 20/18/14

and conclude that the fluid was contaminated. This would be an expensive mistake. ISO 4406 stipulates

that the code applies to particle sizes of 4 µm(c), 6 µm(c) and 14 µm(c), not µm(b). Particle sizes of

4 µm(b), 6 µm(b), 14 µm(b) and 21 µm(b) sizes correspond to 3,6 µm(c), 5,4 µm(c), 12,6 µm(c) and

18,9 µm(c), respectively. The µm(b) concentrations appear higher than those concentrations found for

µm(c) sizes of the same numerical value. Ideally, the sample should be re-analyzed using an Automatic

Particle Counter (APC) calibrated in µm(c), but this is often impossible or impractical. A similar problem

occurs whenever specifications and data (e.g. particle concentrations, ISO codes, or filter Beta Ratios)

are in different units of particle size. Thus, there is a need for a reliable method for converting µm(b) to

µm(c), and then for interpolating to obtain data at the desired particle sizes for contamination control

decisions.

The constrained cubic spline method of interpolation that is used in ISO 11171:2020 to relate particle

concentrations to threshold settings and particle sizes to create calibration curves for APCs, may

be used to interpolate particle concentration and filter Beta Ratio data. Traditional cubic spline

interpolation starts with a series of known data points, the training data set, and interpolates between

them according to the following rules:
— The cubic spline curve passes through all of the known points;
— The curve connecting consecutive points are a third-degree polynomial;
— The first derivative of the curves on each side of a known point are equal;

— The second derivative of the curves on each side of a known point are equal; and

— Boundary conditions are established for the minimum and maximum values of x.

While traditional cubic spline interpolation produces a smooth curve, its usefulness for purposes of

interpolating particle concentration and Beta Ratio data is compromised by a tendency to overshoot

between node points. In contrast, the constrained cubic spline method prevents overshooting and

improves accuracy by sacrificing a little in terms of smoothness. This is accomplished by eliminating

the requirement for second derivatives to be equal. Instead, the first order derivatives on each side of a

point are specified. Since accuracy is paramount in particle counter calibration, the constrained cubic

spline method has been adopted in ISO 11171:2020. The same rationale applies to other fluid power

cleanliness and filter performance applications.

Contamination control decisions should be made using data obtained at the actual sizes defined in

specifications or standards, but this is not always possible or practical. For example, a standard can

specify particle size in units of µm(c), but the available particle count or Beta Ratio data can be from

an APC calibrated to ISO 11171:2016 and reported size in units of µm(b). Similarly, a specification can

use µm(b) sizes from the obsolete ISO 11171:2016, but the available data can be from an APC calibrated

to ISO 11171:2020 which reports size only in units of µm(c). In such cases, the constrained cubic spline

method of interpolation is recommended for estimating particle concentrations and Beta Ratios as a

function of particle size, when data is not available at the specific sizes of interest. It should be noted

that the accuracy of the resultant interpolation is dependent upon the quality of the original data.

Accuracy is sacrificed when the input data contains errors, when there is too little data available for

accurate interpolation, or when the available sizes skew the interpolation.
2 PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 4808:2020(E)
5 Interpolation of particle concentration and Beta Ratio data

Meaningful comparisons of particle concentrations and Beta Ratios can only be made if all data is

reported in the same units of particle size. ISO 11171:2020 standardized on µm(c) as the only acceptable

unit for reporting particle size; hence it is recommended that specifications and historical data utilizing

µm(b) sizes be converted to their corresponding µm(c) sizes. The interpolation of µm(b) to µm(c) data

involves the following steps:
1. Mathemati
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.