New method to determine surface properties at nanoscale

Engineering researchers at Texas Tech University have developed a method for characterizing the surface properties of materials at different temperatures at the nanoscale. Knowing properties of materials at different temperatures is important in engineering, said Gregory McKenna, Professor of chemical engineering and the John R Bradford Endowed, Chair in Engineering. For example, the rubber O-ring that failed during the 1986 space shuttle disaster serves at a tragic case study of what can go wrong when decision-makers don’t take this into account.

The problem, he said, is known properties of a material can radically change at the nanoscale – a tiny scale about 1/1000 of the diameter of a human hair at which scientists have begun building machines that do work. McKenna and graduate student Meiyu Zhai looked at several polymers and explosive materials to see how surface properties varied at the nanoscale and how the surface impacts the nanoscale properties.

Their first results on the “multi-curve method” appeared in the peer-reviewed journal, Journal of Polymer Science Part B: Polymer Physics and was highlighted in Advances in Engineering.

“The nanoscale is a funny range of sizes where materials have properties that are not what we expect, even at a step up at the microscale. We are developing methods to characterize surface properties and relate them to nanoscale behavior using a nanoindenter and other nano-mechanical measurement methods,” said McKenna.

In nanoindentation, researchers can investigate both the elastic properties (how materials spring back when pushed) or the viscous properties (how the material flows). The group has found several surprising results: for example, in other work, the team found extremely thin polycarbonate films become liquid-like at the nanoscale, while they are glassy at the macroscopic size scale. Nanoindentation can be used to relate surface properties to this observation. As machines get smaller and smaller, McKenna said, knowing this information can be invaluable to future engineers.

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New edible, antimicrobial film increases lifespan of soft cheese

Universitat Politecnica de Valencia (UPV) researchers have developed an edible, antimicrobial film that can increase the lifespan of soft cheese. They have used rosemary and oregano oils, and chitosan for producing the film.

Commercial soft cheese has a lifespan of about 21 days when treated with pimaricin and stored in cold storage. Excessive surface dehydration and micro-organism growth can cause deterioration of cheese. This may lead to formation of a slimy texture and odd odors and flavors. Pimaricin is a common antifungal agent that is used for preventing growth of fungus in cheese. Usually, a non-edible polyvinyl acetate plastic coating is also applied which aids in protecting the cheese.

When cheese matures, fungus can grow on its surface, and if the cheese surface has any fissures or faults, then the fungus can enter into these fissures. The newly developed coating can help decrease this growth of fungus on the surface of maturing cheese.

The innovative product developed by the researchers is a natural, edible coating that controls loss of weight and inhibits fungus growth. The researchers tested different oils and found that oregano oil was better than the other oils in preventing fungal growth. This provided the same results as when treated with pimaricin.

The researchers performed a sensorial analysis of the cheese with the edible coating. Over 100 panelists took part in the analysis. When compared with uncoated cheese, the cheese that was coated with essential oils such as oregano and rosemary, received better scores for odour and taste. This test also allowed the researchers to find out the optimum concentration of the essential oil that provided superior antifungal activity and good sensory acceptance.

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Most abundant mineral on earth named as, Bridgmanite

The most abundant mineral on earth that has remained nameless until now will be called Bridgmanite. After a team of American geologists were able to extract a sample large enough to analyze from a meteorite, Bridgmanite was named officially.

Until now, it was referred to as perovskite because according to rules set down by the International Mineralogical Association, a mineral cannot be given a formal name until a specimen has been found that can be examined first hand. The new name is in honour of Percy Bridgman, a pioneer in the use of high pressure experiments to better understand how many geological formations come about.

Bridgmanite makes up about 70 per cent of the earth’s lower mantle and 38 per cent of the total volume of earth. It is made up of high-density magnesium iron silicate.

The lower mantle which starts at 670km under the crust is difficult to reach for samples. The researchers looked at a meteorite that had fallen inside Australia in 1879 as a likely candidate for samples, and found what they were looking for.

Scientists had looked at likely candidate meteorites in the past, but the technique (electron diffraction) they used to look for a bit of perovskite wound up causing it to be destroyed. This time the team used a different, less destructive test - one that involved the use of a micro-focused X-ray beam in conjunction with electron microscopy. The researchers noted that the sample had more sodium and ferric acid than had been expected.

Their discovery is expected to aid future geological research and could offer clues about what goes on when celestial bodies collide, and potentially also about the formation of the universe.

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Bus entirely powered by human, food waste hits roads in UK

The UK’s first bus powered entirely by human and food waste has gone into service between Bristol and Bath. Engineers believe the bus could provide a sustainable way of fuelling public transport - cutting emissions in polluted towns and cities. The 40-seater Bio-Bus, which runs on gas generated through the treatment of sewage and food waste that’s unfit for human consumption, helps to improve urban air quality as it produces fewer emissions than traditional diesel engines.

Running on waste products that are both renewable and sustainable, the bus can travel up to 300km on a full tank of gas generated at Bristol sewage treatment works - a plant run by the company GENeco.

GENeco claim to be the first company in the UK to start injecting gas generated from food waste and sewage into the national gas grid network and at the same time installing a gas refuelling plant for the bus.

“Through treating sewage and food that is unfit for human consumption we’re able to produce enough biomethane to provide a significant supply of gas to the national gas network that’s capable of powering almost 8,500 homes as well as fuelling the Bio-Bus,” said Mohammed Saddiq, General Manager, GENeco.

“Gas powered vehicles have an important role to play in improving air quality in UK cities, but the Bio-Bus goes further than that and is actually powered by people living in the local area, including quite possibly those on the bus itself. Using biomethane in this way not only provides a sustainable fuel, but also reduces our reliance on traditional fossil fuels,” said Saddiq.

The Bio-Bus can travel up to 300km on a full tank of gas, which takes the annual waste of around five people to produce. The first passengers to get on board the Bio-Bus were visitors to the UK who were commuting from Bristol Airport to the city of Bath. Bath Bus Company, which is operating the service, said the bus was greener for the environment.

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3D printed object developed in space

The world’s first zero-gravity 3D printer on the International Space Station (ISS) has created the first object made using additive manufacturing, paving the way for future long-term space expeditions.

“This first print is the initial step towards providing an on-demand machine shop capability away from Earth. The space station is the only laboratory where we can fully test this technology in space,” said Niki Werkheiser, Project Manager, ISS 3D printer at Nasa's Marshall Space Flight Centre in Huntsville, Alabama.

Nasa astronaut Barry Wilmore, Expedition 42 commander aboard the ISS, installed the printer on November 17 and conducted the first calibration test print. Based on the test print results, the ground control team sent commands to realign the printer and printed a second calibration test on November 20. These tests verified that the printer was ready for manufacturing operations.

On November 24, ground controllers sent the printer the command to make the first printed part: a faceplate of the extruder’s casing. This demonstrated that the printer can make replacement parts for itself, said Nasa. The 3-D printer uses a process formally known as additive manufacturing to heat a relatively low-temperature plastic filament and extrude it one layer at a time to build the part defined in the design file sent to the machine.

Wilmore then removed it from the printer and inspected it. Part adhesion on the tray was stronger than anticipated, which could mean layer bonding is different in microgravity, a question the team will investigate as future parts are printed. Wilmore installed a new print tray, and the ground team sent a command to fine-tune the printer alignment and printed a third calibration coupon. When Wilmore removes the calibration coupon, the ground team will be able to command the printer to make a second object. The results from this first print are contributing to a better understanding about the parameters to use when 3-D printing on the space station.

“This is the first time we've ever used a 3-D printer in space, and we are learning, even from these initial operations. As we print more parts we’ll be able to learn whether some of the effects we are seeing are caused by microgravity or just part of the normal fine-tuning process for printing. When we get the parts back on Earth, we'll be able to do a more detailed analysis to find out how they compare to parts printed on Earth,” said Werkheiser.

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Hydrogen Peroxide Bleaching Agent – Infographic

Hydrogen Peroxide First described in 1818 by Louis Jacques Thénard, who produced it by treating barium peroxide with nitric acid. Hydrogen Peroxide is the simplest peroxide (a compound with an oxygen-oxygen single bond) and in its pure form is a colorless liquid, slightly more viscous than water. It is a nonplanar molecule possessing (twisted) C2 symmetry

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Chemical Properties of Hydrogen Peroxide

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Nobel Prize in Chemistry 2014 -Super Resolved Fluorescence Microscopy

The Nobel Prize in Chemistry for 2014 was decided to be awarded to Eric Betzig Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, US; Stefan W Hell, Max Planck Institute for Biophysical Chemistry, Gottingen, and German Cancer Research Center, Heidelberg, Germany and William E Moerner, Stanford University, Stanford, “for the development of super-resolved fluorescence microscopy.”

The development has surpassed the limitations of the light microscope. For a long time optical microscopy was held back by a presumed limitation: that it would never obtain a better resolution than half the wavelength of light. Helped by fluorescent molecules the Nobel Laureates in Chemistry 2014 ingeniously circumvented this limitation. Their ground-breaking work has brought optical microscopy into the nanodimension.

In what has become known as nanoscopy, scientists visualize the pathways of individual molecules inside living cells. They can see how molecules create synapses between nerve cells in the brain; they can track proteins involved in Parkinson’s, Alzheimer’s and Huntington’s diseases as they aggregate; they follow individual proteins in fertilized eggs as these divide into embryos.

It was all but obvious that scientists should ever be able to study living cells in the tiniest molecular detail. In 1873, the microscopist Ernst Abbe stipulated a physical limit for the maximum resolution of traditional optical microscopy: it could never become better than 0.2 micrometres. Eric Betzig, Stefan W. Hell and William E. Moerner are awarded the Nobel Prize in Chemistry 2014 for having bypassed this limit. Due to their achievements the optical microscope can now peer into the nanoworld.

Two separate principles are rewarded. One enables the method stimulated emission depletion (STED) microscopy, developed by Stefan Hell in 2000. Two laser beams are utilized; one stimulates fluorescent molecules to glow, another cancels out all fluorescence except for that in a nanometre-sized volume. Scanning over the sample, nanometre for nanometre, yields an image with a resolution better than Abbe’s stipulated limit.

Eric Betzig and William Moerner, working separately, laid the foundation for the second method, single-molecule microscopy. The method relies upon the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, letting just a few interspersed molecules glow each time. Superimposing these images yields a dense super-image resolved at the nanolevel. In 2006 Eric Betzig utilized this method for the first time.