(Press-News.org) Researchers from the University of Leicester have discovered that when it comes to rubbers, textured surfaces, and reproduction, more fluid formulations have greater reliability than those that are thick and sticky.
Rubber compounds are widely used to mould and produce copies of textured surfaces for scientific analysis, but so far little research has been done to establish which rubbers make the most reliable copies.
A new study published in the academic journal Scientific Reports, led by Professor Mark Purnell from the University of Leicester's Department of Geology, has discovered the best kind of rubber for reproduction.
Professor Purnell explained: "Roughness is something that everyone understands, and the difference between a rough and a smooth surface is obvious, but how do you compare two rough surfaces? How can you tell if surfaces - of the cylinders in your car engine, for example - are smooth enough to perform as they should?
"If you need to make precise measurements of a surface, and you can't take the original surface to the measuring instrument, you would need to analyse a replica. What we haven't known until now is whether the quality of the replica varies depending on the rubber used."
In order to find out what kind of rubber would make the best replica, the Leicester team made multiple copies of a rough and a smooth surface using different rubber compounds, which involved mixing the rubber and then pouring it onto a surface until it solidified.
They analysed the measurements for exactly the same areas of the surfaces, comparing them with each other and with the original surface.
They found that rubber replicas are not comparable with one another and that, in general, high viscosity rubber compounds which pour as thick liquids make replicas that are less similar - and less desirable - compared to the original surface.
Robert Goodall, University of Leicester PhD student and lead author of the paper, added: "If you want good results - with all the ridges and bumps on a surface reproduced at the same scale as the original - you need to use the right rubber for the job."
The types of surface that scientists and engineers make copies of include skin, teeth, superconductor components in particle accelerators, and various tools, including forensic and archaeological investigations. Surfaces are carefully measured to quantify their roughness and texture, but this can be surprisingly tricky.
The importance of a surface's roughness can be seen in car engines, where if the walls of the engine's cylinders are too smooth they will seize, meaning that the surface needs to be just rough enough to carry a film of lubricant to maintain a smooth piston action.
Techniques have now been developed that can make measurements of ridges, bumps and dimples, down to the nanometre scale - less than 1/100 the thickness of a human hair.
INFORMATION:
The paper, 'Accuracy and Precision of Silicon Based Impression Media for Quantitative Areal Texture Analysis' by Robert Goodall, Laurent Darras & Mark Purnell, is published in the journal Scientific Reports and can be found here: http://www.nature.com/srep/2015/150520/srep10800/full/srep10800.html and doi:10.1038/srep10800
The research is funded by the Natural Environment Research Council (NERC).
The fixed-dose drug combination ombitasvir/paritaprevir/ritonavir (trade name Viekirax) has been available since January 2015 for the treatment of adults with chronic hepatitis C infection. The German Institute for Quality and Efficiency in Health Care (IQWiG) examined in a dossier assessment whether this drug combination offers an added benefit over the appropriate comparator therapy.
According to the findings, there are indications of an added benefit in patients who have not yet developed cirrhosis of the liver and who are infected with the hepatitis C virus (HCV) ...
This news release is available in German. FRANKFURT. Scientists at the Goethe University Frankfurt and at the Senckenberg Biodiversity and Climate Research Centre working together with their Canadian counterparts, have reconstructed the climatic development of the Arctic Ocean during the Cretaceous period, 145 to 66 million years ago. The research team comes to the conclusion that there was a severe cold snap during the geological age known for its extreme greenhouse climate. The study published in the professional journal Geology is also intended to help improve prognoses ...
(Edmonton) Each year, thousands of Canadians are given the news: they have skin cancer. It is the most common form of cancer in Canada and around the world, but if detected early, survival rates are extremely high. According to Liam Rourke, it doesn't happen nearly as often as it could.
"The difficulty is that people have a really hard time detecting skin cancer melanomas early," says Rourke, an associate professor in the Faculty of Medicine & Dentistry's Department of Medicine at the University of Alberta. "One of the reasons is that it's an exceptionally difficult task ...
Investigators at Stanford University have found a surprising link between creative problem-solving and heightened activity in the cerebellum, a structure located in the back of the brain and more typically thought of as the body's movement-coordination center.
In designing the study, the researchers drew inspiration from the game Pictionary.
The cerebellum, traditionally viewed as the brain's practice-makes-perfect, movement-control center, hasn't been previously recognized as critical to creativity. The new study, a collaboration between the School of Medicine and ...
Stanford electrical engineer Jelena Vuckovic wants to make computers faster and more efficient by reinventing how they send data back and forth between chips, where the work is done.
In computers today, data is pushed through wires as a stream of electrons. That takes a lot of power, which helps explain why laptops get so warm.
"Several years ago, my colleague David Miller carefully analyzed power consumption in computers, and the results were striking," said Vuckovic, referring to electrical engineering Professor David Miller. "Up to 80 percent of the microprocessor ...
A quantum system never relaxes. An isolated system (like a cloud of cold atoms trapped in optical grids) will endlessly oscillate between its different configurations without ever finding peace. In practice, these types of systems are unable to dissipate energy in any form. This is the exact opposite of what happens in classical physics, where the tendency to reach a state of equilibrium is such a fundamental drive that is has been made a fundamental law of physics, i.e., the second law of thermodynamics, which introduces the concept of entropy.
This profound difference ...
WASHINGTON -- People who earn a college degree before getting married are much less likely to become obese than those who graduate from college after getting married, according to a new study.
"People who get married before they earn a degree from a four-year college are about 65 percent more likely to later become obese than people who get married after college," said Richard Allen Miech, a research professor at the Institute for Social Research at the University of Michigan and the lead author of the study. "While a college degree has long been shown to be associated ...
A fifty-fold between-country difference in rates of paracetamol-induced acute liver failure that leads to liver transplant (ALFT) has been revealed by a study that compared patient data from seven countries at the request of the European Medicines Agency: France, Greece, Ireland, Italy, Netherlands, Portugal and the UK. Researchers discovered that this variation was even more pronounced on a per-capita basis, with a 200-fold difference in ALFT cases. Publishing these findings in the British Journal of Clinical Pharmacology, the authors call for further research to identify ...
Several genes have been lost from the Y chromosome in humans and other mammals, according to research published in the open access journal Genome Biology. The study shows that essential Y genes are rescued by relocating to other chromosomes, and it identifies a potentially important genetic factor in male infertility.
The Y chromosome is dramatically smaller than the X chromosome and has already lost nearly all of the 640 genes it once shared with the X chromosome.
An extreme example of genes disappearing from the Y chromosome can be found in the Ryukyu spiny rat, ...
In what they believe to be the first survey of its kind in the United States, researchers at NYU Langone Medical Center have found that as many as 6 percent of adult New Yorkers who get "inked" -- in other words, those who get a tattoo -- have experienced some form of tattoo-related rash, severe itching or swelling that lasted longer than four months and, in some cases, for many years.
"We were rather alarmed at the high rate of reported chronic complications tied to getting a tattoo," says senior study investigator and NYU Langone dermatologist Marie Leger, MD, PhD, ...
