ThomasNet News Logo
Sign Up | Log In | ThomasNet Home | Promote Your Business

Kelvin Redefined with the Help of Mahr form Measurement System

Print | 
Email |  Comment   Share  

Kelvin Redefined with the Help of Mahr form Measurement System
Kelvin Redefined with the Help of Mahr form Measurement System
Click Here to Enlarge Picture

(Archive News Story - Products mentioned in this Archive News Story may or may not be available from the manufacturer.)

Mahr Federal, Inc.
1144 Eddy St.
Providence, RI, 02905
USA





Press release date: March 7, 2012

German PTB (Physikalisch-Technische Bundesanstalt) defines the unit kelvin with the help of the reference formtester MarForm MFU 110 WP from Mahr

PROVIDENCE, RI - In conjunction with the General Conference on Weights and Measures (CGPM), the kelvin, the basic unit of thermodynamic temperature, is currently being newly defined at the PTB (Physikalisch-Technischen Bundesanstalt) in Braunschweig, Germany, the counterpart of NIST in the US. The goal of PTB's portion of the program is a precise determination of the Boltzmann constant k, the conversion factor between thermal and mechanical energy. The project is being done with the help of a highly accurate reference formtester from Mahr, the MarForm MFU 110 WP, which includes both tactile and optical sensors, and provides accuracy into the nanometer range.

In October of 2011, the CGPM adopted a plan to redefine four of the seven base units of the International System of Units (SI) in terms of the invariants of nature - the fundamental physical constants or properties of atoms. A previous example of this was the redefinition of the meter in 1983, which links it to an exact value of the speed of light in a vacuum. The Conference recommended that efforts be made by the various National Metrology Institutes to reduce the uncertainties of these constants.

The CGPM also noted that, "The kelvin is currently defined in terms of an intrinsic property of water that, while being an invariant of nature, in practice depends on the purity and isotopic composition of the water used." Instead, the Conference suggested that it was "possible to redefine the kelvin so that it is linked to an exact numerical value of the Boltzmann constant k," which links temperature to mechanical energy.

As part of their work to precisely determine the Boltzmann constant, PTB needed to define absolute helium pressures. These were realized with the help of a pressure balance, the essential components of which were piston-cylinder systems. For the precise calculation of pressure, the geometry of the pistons and cylinders at ambient pressure had to be known exactly: hence, PTB's use of the reference formtester from Mahr. This highly precise reference unit is the world's leading instrument for tactile distance and diameter measurements in the measuring range of up to 180 mm.

PTB used the White Point optical stylus system on the MarForm MFU 110 WP to measure the pistons and cylinders. White Point is an optical (interferometrical) stylus system for form measuring machines which allows form and diameter measurements of precision mechanical parts with tolerances of less than 1 Ám. The optical system is based on a novel concept of short coherence heterodyne interferometry working with two wavelengths. Typical parameters are roundness, straightness, parallelism, angle and diameter. The small optical probe allows fast non-contact measurements of very small and hard-to-access geometries, and provides optical contact at two different angles.

The first approach to the calculation of the measurement uncertainty of the generated 3D geometry data showed that the dimensional 3D standard measurement uncertainties only amounted to 7 nm for the piston and 15 nm for the cylinder. This results in a relative measurement uncertainty for the cross-sectional area of 0.7 x 10-6, which may well contribute to decreasing the measurement uncertainty for the Boltzmann constant as a whole.

Mahr Federal Inc., a member of the Mahr Group, has been providing dimensional measurement solutions to fit customer application needs for over 150 years. The company manufactures and markets a wide variety of dimensional metrology equipment, from simple and easy-to-use handheld gages to technically advanced measurement systems for form, contour, surface finish and length. Mahr Federal is also well known as a producer of custom-designed gages and a provider of calibration and contract measurement services. Mahr Federal's calibration laboratories are accredited to ISO/IEC 17025:2005 NVLAP Lab Code 200605-0 (see our Scope of Accreditation for accredited calibration processes). For more information visit http://www.mahr.com

For additional information, contact:
Marketing
Mahr Federal Inc.
1144 Eddy Street
Providence RI 02905 USA
Tel: (800) 343-2050 or (401) 784-3100
Fax: (401) 784-3246
Email: information@mahr.com
Web site: http://www.mahr.com

FOR IMMEDIATE RELEASE

Contact:
Mahr Federal Inc.
Gary Robison
1144 Eddy Street
Providence RI 02905 USA
(401) 784-3275

Media Contact:
THOMAS RANKIN ASSOCIATES
Tom Rankin, APR
401-884-4090
tomr@trankin.com
Print | 
Email |  Comment   Share  
Contacts: View detailed contact information.


 

Post a comment about this story

Name:
E-mail:
(your e-mail address will not be posted)
Comment title:
Comment:
To submit comment, enter the security code shown below and press 'Post Comment'.
 



 See related product stories
More .....
 See more product news in:
Software
Test and Measuring Instruments
 More New Product News from this company:
Video Measuring Microscope offers integrated image processing.
Digital Calipers support wireless data transmission.
Digital Calipers incorporate wireless data transmission.
2D/3D Measuring Station is designed for optical components.
Indicator Calibrator works with diverse range of instruments.
More ....
| Featured Manufacturing Jobs
 Other News from this company:
Mahr Federal to Highlight Digital Calipers and Indicators with Wireless Data Transmission in Special Display at Mfg4
Mahr Federal to Highlight Digital Calipers and Indicators with Wireless Data Transmission in Special Display at Quality Expo Texas
Mahr Federal Air Tool Measures Thousands of Orthopedic Tapers
Mahr Federal To Feature Redesigned MarShaft(TM) Scope Plus At Quality Expo
Mahr Federal Offers Broad Line of MarCal Standard, Special, and Universal Calipers
More ....
 Tools for you
Watch Company 
View Company Profile
Company web site
More news from this company
E-mail this story to a friend
Save Story
Search for suppliers of
Measuring Instruments
Measuring Software
Metrology Instruments
Join the forum discussion at:
Engineers Lounge
Tools of the Trade


Home  |  My ThomasNet News®  |  Industry Market Trends®  |  Submit Release  |  Advertise  |  Contact News  |  About Us
Brought to you by Thomasnet.com        Browse ThomasNet Directory

Copyright © 2014 Thomas Publishing Company. All Rights Reserved.
Terms of Use - Privacy Policy



Error close

Please enter a valid email address