Heated magnetic nanoparticles may be the future of eradicating cancer cells without harming healthy tissue, according to research from the University of Buffalo, USA. The nanoparticles strike tumours with significant heat under a low magnetic field.
Hao Zeng, Professor of Physics at Buffalo, said, ‘The main accomplishment of our work is the greatly enhanced heating performance of nanoparticles under low-field conditions suitable for clinical applications. The best heating power we obtained is close to the theoretical limit, greatly surpassing some of the best performing particles that other research teams have produced.’
Targeting technologies would first direct nanoparticles to tumours within the patient’s body. Exposure to an alternating magnetic field would prompt the particles’ magnetic orientation to flip back and forth hundreds of thousands of times a second, causing them to warm up as they absorb energy from the electromagnetic field and convert it to thermal energy.
Two particles have been tested – manganese-cobalt-ferrite and zinc ferrite. While the manganese particle reached maximum heating power under high magnetic fields, the biocompatible zinc ferrite was efficieny under an ultra-low field.
While this form of treatment, known as magnetic nanoparticle hyperthermia, is not new, the Buffalo-designed particles are able to generate heat several times faster than the current standard.
Hunters don camouflage clothing to blend in with their surroundings. But thermal camouflage – or the appearance of being the same temperature as one’s environment – is much more difficult. Now researchers, reporting in ACS’ journal Nano Letters, have developed a system that can reconfigure its thermal appearance to blend in with varying temperatures in a matter of seconds.
Most state-of-the-art night-vision devices are based on thermal imaging. Thermal cameras detect infrared radiation emitted by an object, which increases with the object’s temperature. When viewed through a night-vision device, humans and other warm-blooded animals stand out against the cooler background. Previously, scientists have tried to develop thermal camouflage for various applications, but they have encountered problems such as slow response speed, lack of adaptability to different temperatures and the requirement for rigid materials. Coskun Kocabas and coworkers wanted to develop a fast, rapidly adaptable and flexible material.
A discovery by scientists at the Department of Energy’s Oak Ridge National Laboratory supports a century-old theory by Albert Einstein that explains how heat moves through everything from travel mugs to engine parts.
The transfer of heat is fundamental to all materials. This new research, published in the journal Science, explored thermal insulators, which are materials that block transmission of heat.
“We saw evidence for what Einstein first proposed in 1911—that heat energy hops randomly from atom to atom in thermal insulators,” said Lucas Lindsay, materials theorist at ORNL. “The hopping is in addition to the normal heat flow through the collective vibration of atoms.”
The random energy hopping is not noticeable in materials that conduct heat well, like copper on the bottom of saucepans during cooking, but may be detectable in solids that are less able to transmit heat.
A new discovery on Titan’s haze is revealing new information about burning fuels on Earth.
Florida International University chemist Alexander Mebel and a team of international researchers have been studying Saturn’s largest moon, trying to unlock a mystery brewing beneath Titan’s thick, hazy atmosphere—How is it that dunes of hydrocarbons exist on the moon’s frozen surface?
On Earth, the kinds of hydrocarbons that cause soot are only known to occur during the combustion process under very high temperatures. They are the kinds of byproducts that engineers usually try to eliminate when engines burn fuel.
By examining data from NASA’s Cassini-Huygens probe, the researchers determined hydrocarbons can form the type of complex chains that create Titan’s orange-brown haze layers at temperatures as low as 90 degrees Kelvin, which is about -298 degrees Fahrenheit—that’s nearly 330 degrees below freezing on Earth.
A team of researchers with the RIKEN Center for Emergent Matter Science and The University of Tokyo, both in Japan, has found a way to force a metal to be a superconductor by cooling it very quickly. In their paper published on the open access site, Science Advances, the group describes their process and how well it worked.
Scientists around the world continue to seek a material that behaves as a superconductor at room temperature—such a material would be extremely valuable because it would have zero electrical resistance. Because of that, it would not increase in heat as electricity passed through it, nor lose energy. Scientists have known that cooling some materials to very cold temperatures causes them to be superconductive. They have also known that some metals fail to do so because they enter a “competing state.” In this new effort, the researchers in Japan have found a way to get one such non-cooperative metal to enter a superconductive state anyway—and to stay that way for over a week.
Temperature is tough to measure, especially in shock compression experiments. A big challenge is having to account for thermal transport—the flow of energy in the form of heat.
To better understand this challenge, researchers from Lawrence Livermore National Laboratory (LLNL) have taken important steps to show that thermal conduction is important and measurable at high pressureandtemperature conditions in these types of experiments, according to a paper recently published in the Journal of Applied Physics. The paper’s authors are David Brantley, Ryan Crum and Minta Akin.
“We need better temperature measurements because understanding rocky-type planetary materials’ high temperature and pressure behavior is key to developing better models of Earth and other terrestrial exoplanets,” said David Brantley, LLNL physicist and lead author of the paper.
Brantley said that depending on how iron conducts heat at Earth’s core pressure and temperatures, the planet’s solid inner core could be around 500 million to several billion years old.
A new approach for studying friction on ice helps explain why the ease of sliding depends strongly on temperature, contact pressure, and speed.
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In Latvia, where bobsledding, luge, and skeleton are popular, ice can be more than just “slippery.” The local language has another term slīdamība—roughly translated as “slideability”—which refers to the ease of movement on a surface. This terminology signifies the awareness that sliding on ice depends on multiple factors—something physicists have had trouble explaining despite 160 years of effort. Previous work has focused on the water layer that forms between the ice surface and the sliding object, say, an ice skate. However, this model does not show why friction is higher near the ice melting point than it is at lower temperatures (Fig. 1). A new study of the solid properties of ice may provide a solution. Rinse Liefferink from the University of Amsterdam and colleagues have performed a series of experiments, in which they measure both the friction of a sliding object and the hardness of ice over a wide range of conditions [1]. The observations show that the hardness decreases as the temperature increases, leading to a high-friction “ploughing” behavior once the sliding object is able to penetrate the softer ice surface. This novel approach to studying ice friction could help in developing technologies that improve safety for winter drivers or give an edge to winter athletes.
Piezoelectric materials hold great promise as sensors and as energy harvesters but are normally much less effective at high temperatures, limiting their use in environments such as engines or space exploration. However, a new piezoelectric device developed by a team of researchers from Penn State and QorTek remains highly effective at elevated temperatures.
Clive Randall, director of Penn State’s Materials Research Institute (MRI), developed the material and device in partnership with researchers from QorTek, a State College, Pennsylvania-based company specializing in smart material devices and high-density power electronics.
“NASA’s need was how to power electronics in remote locations where batteries are difficult to access for changing,” Randall said. “They also wanted self-powering sensors that monitor systems such as engine stabilities and have these devices work during rocket launches and other high-temperature situations where current piezoelectrics fail due to the heat.”
An international team of researchers, affiliated UNIST has introduced an exiting new organic network structure that shows pure organic ferromagnetic property at room temperature. As described in the CHEM journal this pure organic material exhibits ferromagnetism from pure p-TCNQ without any metal contamination.
This breakthrough has been led by by Professor Jong-Beom Baek and his research team in the School of the Energy and Chemical Engineering at UNIST. In the study, the research team has synthesized a network structure from the self polymerization of tetracyanoquinodimethane (TCNQ) monomer. The designed organic network structure generates stable neutral radicals.
For over two decades, there has been widespread scepticism around claims of organic plastic ferromagnetism, mostly due to contamination by transition metals. Extensive effort has been devoted to developing magnets in purely organic compounds based on free radicals, driven by both scientific curiosity and the potential applications of a ‘plastic magnet’. Excluding the contamination issues and realizing magnetic properties from pure organic plastics must occur to revive the quest for plastic magnetism.
The Masdar Institute of Science and Technology, an independent, research-driven graduate-level university focused on advanced energy and sustainable technologies, today announced that its researchers have successfully demonstrated that desert sand from the UAE could be used in concentrated solar power (CSP) facilities to store thermal energy up to 1000°C.
The research project called ‘Sandstock’ has been seeking to develop a sustainable and low-cost gravity-fed solar receiver and storage system, using sand particles as the heat collector, heat transfer and thermal energy storage media.
Desert sand from the UAE can now be considered a possible thermal energy storage (TES) material. Its thermal stability, specific heat capacity, and tendency to agglomerate have been studied at high temperatures.
Dr. Behjat Al Yousuf, Interim Provost, Masdar Institute, said, “The research success of the Sandstock project illustrates the strength of our research and its local relevance. With the launch of the MISP in November, we have further broadened the scope of our solar energy research and we believe more success will follow in the months ahead.”
It is an understatement to say that chemical reactions take place everywhere, constantly. In both nature and the lab, chemistry is ubiquitous. But despite advances, it remains a fundamental challenge to gain a complete understanding and control over all aspects of a chemical reaction, such as temperature and the orientation of reacting molecules and atoms.
This requires sophisticated experiments where all the variables that define how two reactants approach, and ultimately react with, each other can be freely chosen. By controlling things like the speed and the orientation of the reactants, chemists can study the finest details of a particular reaction mechanism.
In a new study, a team led by Andreas Osterwalder at EPFL’s Institute of Chemical Sciences and Engineering, working with theorists from the University of Toronto, have built an apparatus that allows them to control the orientation and energies of reacting atoms, down to nearly absolute zero. “It’s the coldest formation of a chemical bond ever observed in molecular beams,” says Osterwalder. A molecular beam is a jet of gas inside a vacuum chamber, frequently used in spectroscopy and studies in fundamental chemistry.
A color developed by Egyptians thousands of years ago has a modern-day application as well – the pigment can boost energy efficiency by cooling rooftops and walls, and could also enable solar generation of electricity via windows.
Egyptian blue, derived from calcium copper silicate, was routinely used on ancient depictions of gods and royalty. Previous studies have shown that when Egyptian blue absorbs visible light, it then emits light in the near-infrared range. Now a team led by researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has confirmed the pigment’s fluorescence can be 10 times stronger than previously thought.
Measuring the temperature of surfaces coated in Egyptian blue and related compounds while they are exposed to sunlight, Berkeley Lab researchers found the fluorescent blues can emit nearly 100 percent as many photons as they absorb. The energy efficiency of the emission process is up to 70 percent (the infrared photons carry less energy than visible photons).
An international group of scientists, including a researcher from Skoltech, has completed an experimental and theoretical study into the properties displayed by strongly disordered superconductors at very low temperatures. Following a series of experiments, the scientists developed a theory that effectively describes the previously inexplicable anomalies encountered in superconductors. The results of the study were published in Nature Physics.
The phenomenon of superconductivity was discovered in 1911 by a group of scientists led by Dutch physicist Heike Kamerlingh Onnes. Superconductivity means complete disappearance of electrical resistance in a material when it is cooled down to a specific temperature, resulting in the magnetic field being forced out from the material. Of particular interest to scientists are strongly disordered superconductors whose atoms do not form crystal lattices. From a practical standpoint, strongly disordered superconductors hold great potential for quantum computer development.
Novel design could help shed excess heat in next-generation fusion power plants
A class exercise at MIT, aided by industry researchers, has led to an innovative solution to one of the longstanding challenges facing the development of practical fusion power plants: how to get rid of excess heat that would cause structural damage to the plant.
The new solution was made possible by an innovative approach to compact fusion reactors, using high-temperature superconducting magnets. This method formed the basis for a massive new research program launched this year at MIT and the creation of an independent startup company to develop the concept. The new design, unlike that of typical fusion plants, would make it possible to open the device’s internal chamber and replace critical components; this capability is essential for the newly proposed heat-draining mechanism.
The new approach is detailed in a paper in the journal Fusion Engineering and Design, authored by Adam Kuang, a graduate student from that class, along with 14 other MIT students, engineers from Mitsubishi Electric Research Laboratories and Commonwealth Fusion Systems, and Professor Dennis Whyte, director of MIT’s Plasma Science and Fusion Center, who taught the class.
Electrical engineering researchers have boosted the operating temperature of a promising new semiconductor laser on silicon substrate, moving it one step closer to possible commercial application.
The development of an “optically pumped” laser, made of germanium tin grown on silicon substrates, could lead to faster micro-processing speed of computer chips, sensors, cameras and other electronic devices—at much lower cost.
“In a relatively short time period—roughly two years—we’ve progressed from 110 Kelvin to a record temperature of 270K,” said Shui-Qing “Fisher” Yu, associate professor of electrical engineering. “We are now very close to room-temperature operation and moving quickly toward the application of a material that can significantly increase processing speed with much less power consumption.”
Yu leads a multi-institutional team of researchers on developing a laser injected with light, similar to an injection of electrical current. The improved laser covers a broader wavelength range, from 2 to 3 micrometers, and uses a lower lasing threshold, while capable of operating at 270 Kelvin, which is roughly 26 Farenheit.
Using powerful computer simulations, researchers from Brown University have identified a material with a higher melting point than any known substance.
The computations, described in the journal Physical Review B (Rapid Communications), showed that a material made with just the right amounts of hafnium, nitrogen, and carbon would have a melting point of more than 4,400 kelvins (7,460 degrees Fahrenheit). That’s about two-thirds the temperature at the surface of the sun, and 200 kelvins higher than the highest melting point ever recorded experimentally.
The experimental record-holder is a substance made from the elements hafnium, tantalum, and carbon (Hf-Ta-C). But these new calculations suggest that an optimal composition of hafnium, nitrogen, and carbon – HfN0.38C0.51 – is a promising candidate to set a new mark. The next step, which the researchers are undertaking now, is to synthesize material and corroborate the findings in the lab.
“The advantage of starting with the computational approach is we can try lots of different combinations very cheaply and find ones that might be worth experimenting with in the lab,” said Axel van de Walle, associate professor of engineering and co-author of the study with postdoctoral researcher Qijun Hong. “Otherwise we’d just be shooting in the dark. Now we know we have something that’s worth a try.”
A team of researchers at the Institute of Synthetic Polymer Materials of the Russian Academy of Sciences, MIPT and elsewhere has determined how the regularity of polypropylene molecules and thermal treatment affect the mechanical properties of the end product. Their new insights make it possible to synthesize a material with predetermined properties such as elasticity or hardness. The paper detailing the study was published in Polymer.
In terms of production volume, polypropylene it is second only to polyethylene. By tweaking its molecular structure, polypropylene can be used to manufacture materials with a wide range of features, from elastic bands to high-impact plastic. However, the relationship between the polymer’s chemical structure and its mechanical properties is not fully understood.
What makes the properties of polymer materials so variable is their makeup. A polymer molecule is a long chain of repeating units of unequal length. If these molecules are jumbled up more or less at random in a material, it is said to be amorphous. Such polymers are soft. In other materials, the polymer chains form interconnections called crosslinks. This gives rise to regions of highly regular atomic structure (fig. 1), similar to that of crystals, hence the name crystallites. They hold the whole molecular network together, and the more crystallites there are in a material, the harder it is. To form crosslinks, molecular chains need to possess a certain structural regularity called isotacticity.
When a fragile surface requires a rock-hard, super-thin bonded metal coating, conventional manufacturing processes come up short. However, Cold Gas Dynamic Spray (CGDS) can do just that - with a big caveat. CGDS is enormously versatile, but is also very difficult to predict key aspects of the entire process. Now a temperature-based 3D model by Professor Tien-Chien Jen from the University of Johannesburg starts unlocking the mysteries of the CGDS film-growing process in the particle deposition zone.
Themodel is the first to connect the dots between particle impact velocity, energy transformation, and temperature rise in the particle impact zone, in three dimensions.
CGDS is already used extensively to manufacture or repair metal parts for large passenger airliners, as well as mobile technology and military equipment.
In the process, a de Laval nozzle sprays micron-sized metal particles over a short distance, typically 25mm, at a metal or polymer surface. The particles impact the surface at speeds ranging from 300 meters per second to 800 meters per second. As a frame of reference, the speed of sound is 343 meters per second.
Sunspots!! They are planet-sized dark spots in the solar photosphere, aka the surface of the Sun. Found in active regions, sunspots look dark because they are slightly cooler than the rest of the surface. The temperature of sunspots is usually about 4,000 kelvins compared to the rest of the surface at 6,000 kelvins. These sunspots in the above image are in active region AR2835, which also happens to be the largest active region now crossing the Sun. The picture shows a field of view that spans about 150,000 kilometers or over ten Earth diameters. With powerful magnetic fields, solar active regions are often responsible for solar flares and coronal mass ejections, storms which affect space weather near Earth.
Image Credit & Copyright: Michael Teoh, Heng Ee Observatory, Penang, Malaysia
