 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
New Measurement Guide Worth 'Poring Over'
Gaithersburg MD (SPX) Nov 15, 2006 In industries from textiles to automobiles and from pharmaceuticals to semiconductors, accurately measuring empty spaces--technically speaking, porosity--is a substantial matter, important to efforts to ensure high product quality and low scrap rates. This is because tiny pores--usually smaller than 50 nanometers in diameter--come in many varieties, creating complex internal and external surface features that strongly influence the performance of catalysts, filters, brake pads, pigments, ceramic components, time-release capsules and many other engineered products. A new Recommended Practice Guide from the National Institute of Standards and Technology (NIST) provides useful advice and instruction on how to analyze the size, distribution and total volume of tiny pores. The 79-page manual, Porosity and Specific Surface Area Measurement for Solid Materials, was jointly produced by scientists from NIST and Germany's Federal Institute for Materials Research and Testing (BAM). The two government research organizations are collaborating to produce certified reference materials. These reference materials are carefully characterized samples that serve as benchmarks for evaluating the accuracy of instruments used to measure the chemical composition or certain physical properties of materials. For example, NIST and BAM offer samples of alumina beads (NIST Standard Reference Material 1917) with certified values for pore volume, mean pore diameter, and most common pore diameter. Industry uses a variety of methods to measure the surface area and pore characteristics of powders and other materials characterized by large surface-to-volume ratios. Differences among the methods complicate efforts to compare and interpret measurement results. Also, strengths and limitations of the various techniques are important for manufacturers to know when designing materials with pore sizes and distributions optimized for specific applications and products. The new guide details the "practical issues that need to be considered when conducting a measurement or analysis" by one or more of the commonly used porosimetry techniques. Community Email This Article Comment On This Article Related Links National Institute of Standards and Technology (NIST) Nano Technology News From SpaceMart.com Nano Technology News From SpaceMart.com Computer Chip Architecture, Technology and Manufacture
New Techniques Pave Way For Carbon Nanotubes In Electronic Devices
Troy NY (SPX) Nov 13, 2006Many of the vaunted applications of carbon nanotubes require the ability to attach these super-tiny cylinders to electrically conductive surfaces, but to date researchers have only been successful in creating high-resistance interfaces between nanotubes and substrates. Now a team from Rensselaer Polytechnic Institute reports two new techniques, each following a different approach, for placing carbon nanotube patterns on metal surfaces of just about any shape and size. |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
