The researchers put their innovation—thin squares of plastic saturated with vapors of a common solvent—through the paces at four testing laboratories. The prototype test material, made at Virginia Tech, yielded measurement results more accurate than those previously achieved in more costly and time-consuming interlaboratory studies using less standardized materials.
The researchers suggest that their method might be used to produce a range of reference materials to validate measurements of VOCs emitted from building materials and products. VOCs are used in paints, adhesives, furniture and many other indoor products. Indoor levels of some VOCs average two to five times higher than outdoors, according to the Environmental Protection Agency.VOC emissions from building materials and products have been linked to occupant illness, reduced worker productivity, and increased requirements for ventilation/air cleaning, leading to increased energy consumption. As a result, low VOC emitting products are being used more widely in buildings to help achieve a healthy and sustainable indoor environment.
Past evaluations of test performance have been based on how much measurements reported by individual laboratories differ from the average value for the entire set of laboratories. "These kinds of inter-laboratory comparisons can take months to conduct," explains NIST environmental engineer Cynthia Howard-Reed, lead author of the new report, "and, unfortunately, the results are relative because there is no true reference value for determining just how accurate an emission measurement really is."
That's the gap the researchers are trying to fill. They aim to produce VOC reference materials—standardized test samples that produce known results when analyzed. These benchmark references are commonly used in industry to check the accuracy of important measurement instruments.
In the initial trial, they prepared two batches of their sample material—thin films of polymethyl pentane, a plastic used in gas-permeable packaging, saturated with toluene, a common VOC found in paint and other products. A mathematical model developed by the research team is used to accurately predict rates of emission from the sample over time. The preliminary multi-laboratory tests showed that the prototype reference material is uniform in composition and sufficiently stable and that rates of VOC emissions within and between production batches are consistent.
The researchers conclude that their prototype could reduce inter-laboratory variability in results to less than 10 percent—much better than current methods.
The pilot study also identified several opportunities for improvement, which will be incorporated before an international pilot is conducted later this year. With further progress, the project will be expanded by 2013 to include more types of VOC references that will be produced in larger batches for broader distribution.
* C. Howard-Reed , Z. Liu, J. Benning , S. Cox, D. Samarov, D. Leber, A.T. Hodgson, S. Mason, D. Won and J.C. Little. Diffusion-controlled reference material for volatile organic compound emissions testing: Pilot inter-laboratory study. Building and Environment 46 (2011) 1504-1511.
Mark Bello | EurekAlert!
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses