Researchers develop new energy-efficient technique to weld steel and aluminum

 

Cars could soon be lighter and stronger, thanks to vaporized foil actuator welding (Credit: Shutterstock) As manufacturers, particularly in the automobile industry, continue to work toward incorporating lighter metals like aluminum with heavier steel, the ongoing problem has been how to successfully weld them together. The problem is that the high heat created in the welding process actually weakens these lighter metals, creating a less than optimum weld. After 10 years of research, engineers at The Ohio State University have developed a new welding technique that may prove to solve this problem while also using 80 percent less energy and creating bonds that are 50 percent stronger. "With our method, materials are shaped and bonded together at the same time, and they actually get stronger," says Glenn Daehn, professor of materials science and engineering at Ohio State, who helped develop the new technique. The traditional technique, called spot resistant welding, works by passing an electrical current through pieces of metal using the natural electrical resistance within those metals. This generates heat that melts them together to form a weld. This process consumes a lot of energy, and the melted metals are left in a weaker state than they were before. What Daehn and his team have done is create a new welding method called vaporized foil actuator (VFA) using short high voltage electrical pulses (lasting millionths of a second) passed through an aluminum foil, and a burst of hot gas traveling at speeds approaching thousands of miles per hour, to bond the atoms of one metal to atoms on the other. Since the two different bonded metals don’t melt, neither metal is weakened and the resulting seam is stronger. The energy savings comes from the fact that the electrical pulse is so short and the required energy to vaporize the foil is less than is necessary to melt the parts together in a traditional process. Daehn and his team have already used the process to successfully bonded different combinations of copper, aluminum, magnesium, iron, nickel and titanium. They have created strong bonds between commercial steel and aluminum alloys – a feat which is impossible normally. VFA is evidently also able to shape metal parts during the welding process, which could save manufacturers an additional step. In 2012, Honda announced it had created a similar result, welding aluminum to steel using a variation of a process called friction stir welding (FSW). Rather than the high heat and gas applied to a third element like the aluminum foil used in the VFA process, FSW uses heat, friction and pressure with a third element to meld two metals together. Like VFA, it uses less energy and creates a bond that has been proven to be stronger than that created by a traditional welding process. Variations of FSW have since been used by Lincoln, Mazda and Audi. Source: The Ohio State University   http://www.gizmag.com/vaporized-foil-actuator-welding/40137/

3D printed teeth kill bacteria

 

Dental implants could soon have built-in antibacterial properties (Credit:Shutterstock) Creating replacement parts for various bits of the human body is one of the many areas in which 3D printing has huge potential. Dental implants are on that list, too, and if new research out of the University of Groningen in the Netherlands comes to fruition, 3D-printed replacement teeth could come with the added bonus of being able to destroy 99 percent of bacteria that they come into contact with. The research team, led by Andreas Hermann, has developed a process to manufacture 3D-printed teeth and braces capable of destroying bacteria using a special type of antimicrobial resin. To create the resin, the researchers combined antibacterial ammonium salts with standard dental resins. The resultant mixture was then hardened using ultraviolet light and put inside a 3D printer to print samples of replacement teeth. The positive charge on the ammonium salts gives the resin its bacteria-killing property, disrupting negatively charged bacterial membranes and causing them to burst and die. To test the antibacterial capacity of the resin the researchers applied a mixture of saliva and tooth decay-causing bacteria Streptococcus mutans on the samples of the replacement teeth and found that the material was effective in destroying 99 percent of the bacteria colonies on the sample. The material can kill bacteria on contact but is not harmful to human cells, Hermann told New Scientist. It's not all smiles though. In a review of the study Nicholas Staropoli, a research associate for the American Council on Science and Health, points out that while the teeth could prevent oral infections, such as endocarditis, and preserve dental implants, it could also wipe out helpful bacteria that help protect a person from harmful pathogens. As of now the material is still a prototype and according to the researchers further testing will be required before human trials can be conducted. In addition to inhibiting bacterial damage to teeth implants, the researchers believe the material may also be suitable for orthopaedic and non-medical applications, such as water purification, food packaging and children’s toys. The research paper entitled 3D-Printable Antimicrobial Composite Resins is published in the journal Advanced Functional Materials.   http://www.gizmag.com/3d-printer-teeth-kill-bacteria/40161/

Lack of 'sleep' may zap cell growth, brain activity, study in plants suggests

 

Lack of adequate sleep can do more than just make you tired. It can short-circuit your system and interfere with a fundamental cellular process that drives physical growth, physiological adaptation and even brain activity, according to a new study from the University of Tennessee, Knoxville. Albrecht von Arnim, a molecular biologist based in the Department of Biochemistry and Cellular and Molecular Biology, studied plants but said the concepts may well translate to humans. His team examined how protein synthesis--the process that determines how organisms grow and how cells renew themselves--changes over the course of the daily day-night cycle. He also explored whether any such changes are controlled by the organism's internal time keeper, the circadian clock. Proteins are newly created in every cell by translating messages made from the cell's own DNA, the genome. Von Arnim's findings, published in the journal Plant Cell, show not only that protein synthesis activity changed over the course of the day, but also that it was under the influence of the circadian clock. "When we misalign our behavior with our circadian clock, for example by creating jet lag, or by working as a night owl, we do not only disrupt normal physiological processes such as cycles of appetite and body temperature," von Arnim said. "This work in plants suggests that we may also be interfering with a more fundamental cellular process, protein synthesis." Muscle action, brain activity, growth and development are functions all performed by proteins whose synthesis is carefully regulated, he said. "For example, when cells are stressed by high temperatures or from a virus infection, they drastically reduce their protein synthesis activity," von Arnim said. The findings could also have implications for agricultural production as farmers and companies seek to better cultivate land and maximize outputs from plants required to sustain human life. "Protein synthesis is part of the basis for crop yield," von Arnim said. Story Source: The above post is reprinted from materials provided by University of Tennessee at Knoxville. Note: Materials may be edited for content and length. Journal Reference: Anamika Missra et al. The Circadian Clock Modulates Global Daily Cycles of mRNA Ribosome Loading. The Plant Cell, 2015 DOI:10.%u200B1105/%u200Btpc.%u200B15.%u200B00546 http://www.sciencedaily.com/releases/2015/10/151030153115.htm

Qualities admired in another from far away can be threatening as that person approaches

 

What people believe they want and what they might actually prefer are not always the same thing. And in the case of being outperformed as an element of romantic attraction, the difference between genuine affinity and apparent desirability becomes clearer as the distance between two people gets smaller. In matters of relative performance, distance influences attraction. For example, someone of greater intelligence seems attractive when they're distant or far away in your mind. But less so when that same person is right next to you, according to a new study by a University at Buffalo-led research team published in the latest edition of the journal Personality and Social Psychology Bulletin. "We found that men preferred women who are smarter than them in psychologically distant situations. Men rely on their ideal preferences when a woman is hypothetical or imagined," said Lora Park, associate professor in the UB Department of Psychology and the study's principal investigator. "But in live interaction, men distanced themselves and were less attracted to a woman who outperformed them in intelligence." Previous research has shown that similarities between individuals can affect attraction. This new set of studies suggests that psychological distance -- whether someone is construed as being near or far in relation to the self -- plays a key role in determining attraction. "It's the distinction between the abstract and the immediate," says Park. "There is a disconnect between what people appear to like in the abstract when someone is unknown and when that same person is with them in some immediate social context." Even though the research focus of the current study was on romantic attraction and, specifically, men's interest in women, Park says the result might potentially be a broader phenomenon, extending to other interpersonal situations. "That's a question for future research," she said. "But presumably, anyone who is outperformed by someone close to them might feel threatened themselves. We just happened to look at men in a romantic dating context." Park's team conducted six separate studies involving 650 young adult subjects. The studies ranged from presenting subjects with hypothetical women, to women they expected to meet, to actually engaging in an interpersonal interaction. "In each case, how much you like someone or how much you are attracted to them is affected by how intelligent that person is relative to you and how close that person is relative to you," said Park. But the area of performance has to be something important to the individual. "The domain matters," says Park. "If you don't care about the domain, you might not be threatened. Yet, if you care a lot about the domain, then you might prefer that quality in somebody who is distant, then feel threatened when that person gets close to you." Story Source: The above post is reprinted from materials provided by University at Buffalo. The original item was written by Bert Gambini. Note: Materials may be edited for content and length. http://www.sciencedaily.com/releases/2015/10/151030161339.htm