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Category: materials – Page 158

Social media users may trust artificial intelligence (AI) as much as human editors to flag hate speech and harmful content, according to researchers at Penn State.

The researchers said that when users think about positive attributes of machines, like their accuracy and objectivity, they show more faith in AI. However, if users are reminded about the inability of machines to make subjective decisions, their trust is lower.

The findings may help developers design better AI-powered content curation systems that can handle the large amounts of information currently being generated while avoiding the perception that the material has been censored, or inaccurately classified, said S. Shyam Sundar, James P. Jimirro Professor of Media Effects in the Donald P. Bellisario College of Communications and co-director of the Media Effects Research Laboratory.

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Circa 2019 face_with_colon_three

The most widely used methods for transdermal administration of the drugs are hypodermic needles, topical creams, and transdermal patches. The effect of most of the therapeutic agents is limited due to the stratum corneum layer of the skin, which serves as a barrier for the molecules and thus only a few molecules are able to reach the site of action. A new form of delivery system called the microneedles helps to enhance the delivery of the drug through this route and overcoming the various problems associated with the conventional formulations. The primary principle involves disruption of the skin layer, thus creating micron size pathways that lead the drug directly to the epidermis or upper dermis region from where the drug can directly go into the systemic circulation without facing the barrier. This review describes the various potential and applications of the microneedles. The various types of microneedles can be fabricated like solid, dissolving, hydrogel, coated and hollow microneedles. Fabrication method selected depends on the type and material of the microneedle. This system has increased its application to many fields like oligonucleotide delivery, vaccine delivery, insulin delivery, and even in cosmetics. In recent years, many microneedle products are coming into the market. Although a lot of research needs to be done to overcome the various challenges before the microneedles can successfully launch into the market.

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Physicists have discovered a material in which atoms are arranged in a way that so frustrates the movement of electrons that they engage in a collective dance where their electronic and magnetic natures appear to both compete and cooperate in unexpected ways.

Led by Rice University physicists, the research was published online today in Nature. In experiments at Rice, Oak Ridge National Laboratory (ORNL), SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory (LBNL), the University of Washington (UW), Princeton University and the University of California, Berkeley, researchers studied pure iron-germanium crystals and discovered standing waves of fluid electrons appeared spontaneously within the crystals when they were cooled to a critically low temperature. Intriguingly, the arose while the material was in a , to which it had transitioned at a higher temperature.

“A charge wave typically occurs in materials that have no magnetism,” said study co-corresponding author Pengcheng Dai of Rice. “Materials that have both a charge density wave and magnetism are actually rare. Even more rare are those where the charge density wave and magnetism ‘talk’ to each other, as they appear to be doing in this case.”

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Atomically thin materials such as graphene have drawn attention for how electrons can race in them at exceptionally quick speeds, leading to visions of advanced new electronics. Now scientists find that similar behavior can exist within two-dimensional sheets, known as domain walls, that are embedded within unusual crystalline materials. Moreover, unlike other atomically thin sheets, domain walls can easily be created, moved, and destroyed, which may lead the way for novel circuits that can instantly transform or be repaired on command.

In the new study, researchers investigated crystalline lithium niobate ferroelectric film just 500 nanometers thick. Electric charges within materials separate into positive and negative poles, and ferroelectrics are materials in which these electric dipoles are generally oriented in the same direction. The electric dipoles in ferroelectrics are clustered in regions known as domains. These are separated by two-dimensional layers known as domain walls.

The amazing electronic properties of two-dimensional materials such as graphene and molybdenum disulfide have led researchers to hope they may allow Moore’s Law to continue once it becomes impossible to make further progress using silicon. Researchers have also investigated similarly attractive behavior in exceptionally thin electrically conducting heterointerfaces between two different insulating materials, such as lanthanum aluminate and strontium titanate.

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A team of researchers at University College London, working with a colleague from Nylers Ltd. and another from XPCI Technology Ltd., has developed a new way to X-ray luggage to detect small amounts of explosives. In their paper published in the journal Nature Communications, the group describes modifying a traditional X-ray device and applying a deep-learning application to better detect explosive materials in luggage.

Prior research has shown that when X-rays strike materials, they produce tiny bends that vary depending on the type of material. They sought to take advantage of these bends to create a precision X-ray machine.

The researchers first added a small change to an existing X-ray machine—a box containing masks, which are sheets of metal with tiny holes in them. The masks serve to split the X-ray beam into multiple smaller beams. The researchers then used the device to scan a variety of objects containing embedded and fed the results to a deep-learning AI application. The idea was to teach the machine what the tiny bends in such materials looked like. Once the machine was trained, they used it to scan other objects with embedded explosives to see if it could identify them. The researchers found their machine to be 100% accurate under lab settings.

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Dielectric mirrors, also referred to as Bragg mirrors, reflect light nearly completely. Hence, they are suited for various applications, such as camera systems and sensor systems for microscopy and medical technologies. So far, such mirrors have been produced by complex processes in expensive vacuum devices. Researchers from Karlsruhe Institute of Technology (KIT) now are the first to print Bragg mirrors of high quality with inkjet printers. This may pave the way towards the digital manufacture of customized mirrors.

Research results are published in Advanced Materials (“Fabrication of Bragg Mirrors by Multilayer Inkjet Printing”).

Bragg mirrors are produced by applying several thin layers of materials onto a carrier. The resulting optical mirror specifically reflects the light of a certain wavelength. Reflectivity of a Bragg mirror depends on the materials, the number of layers applied, and their thicknesses. So far, Bragg mirrors have been produced in expensive vacuum production facilities. KIT researchers now were the first to print them on different carriers. This largely facilitates production.

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Topological materials that possess certain atomic-level symmetries, including topological insulators and topological semi-metals, have elicited fascination among many condensed matter scientists because of their complex electronic properties. Now, researchers in Japan have demonstrated that a normal semiconductor can be transformed into a topological semi-metal by light irradiation. Further, they showed how spin-dependent responses could appear when illuminated with circularly-polarized laser light. Published in Physical Review B, this work explores the possibility of creating topological semi-metals and manifesting new physical properties by light control, which may open up a rich physical frontier for topological properties.

Most ordinary substances are either , like metals, or insulators, like plastic. In contrast, can exhibit unusual behavior in which electrical currents flow along the surface of the sample, but not inside the interior. This characteristic behavior is strongly connected to topological properties inherent in the electronic state. Furthermore, a novel phase called a topological semi-metal provides a new playground for exploring the role of topology in condensed matter. However, the underlying physics of these systems is still being pondered.

Researchers at the University of Tsukuba studied the dynamics of excitations in zinc arsenide (Zn3As2) when irradiated with a laser with circular polarization. Zinc arsenide is normally thought of as a narrow-gap semiconductor, which means that electrons are not free to move around on their own but can be easily propelled by energy from an external light source. Under the right conditions, the material can show a special topological state called a “Floquet-Weyl semi-metal,” which is a topological semi-metal coupled with light. In this case, the can be carried in the form of quasiparticles called Weyl fermions. Because these quasiparticles travel as if they have zero mass and resist becoming scattered, Weyl fermions can move easily through the material.

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Today, an international team of researchers led by Séamus Davis, Professor of Physics at the University of Oxford and University College Cork, has announced results that reveal the atomic mechanism behind high-temperature superconductors. The findings are published in PNAS.

Superconductors are materials that can conduct electricity with zero resistance, so that an electric current can persist indefinitely. These are already used in various applications, including MRI scanners and high-speed maglev trains, however superconductivity typically requires extremely low temperatures, limiting their widespread use. A major goal within physics research is to develop super conductors that work at , which could revolutionize energy transport and storage.

Certain copper oxide materials demonstrate superconductivity at higher temperatures than conventional superconductors, however the mechanism behind this has remained unknown since their discovery in 1987.

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Many of us are all too familiar with how strain in work relationships can impact performance, but new research shows that materials in electricity-producing fuel cells may be sensitive to strain on an entirely different level.

Researchers from Kyushu University report that strain caused by just a 2% reduction in the distance between atoms when deposited on a surface leads to a whopping 99.999% decrease in the speed at which the materials conduct , greatly reducing the performance of solid oxide cells.

Developing methods to reduce this strain will help bring high-performance fuel cells for clean energy production to a wider number of households in the future.

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Magnetorotational instability—a process that might explain the dynamics of astrophysical accretion disks—has finally been observed in the laboratory.

What do black holes, forming stars, and a tank of liquid metal in Princeton, New Jersey, have in common? The first two might and the third one definitely does play host to an important process in magnetized-fluid dynamics called magnetorotational instability (MRI). MRI has been well studied theoretically and computationally, and related processes have been seen experimentally [1]. But until now, there has not been an unambiguous laboratory confirmation of its existence. Yin Wang and his colleagues at Princeton University have demonstrated MRI in an ingenious liquid-metal experiment—the culmination of more than 20 years of work [2].

The team’s discovery is significant because MRI has long been suspected of being at the heart of accretion [3]. Accretion, in which material spirals inward in a flattened disk around a black hole or a young star, is a major source of the light coming from those objects. For accretion to occur, the material in the disk must lose its angular momentum. However, angular momentum is conserved: much like the trash we generate in our daily lives, it does not cease to exist when it is not wanted. Instead, angular momentum must be passed from the inner parts of the disk to the outer parts. What drives this angular-momentum transport has long been a mystery.

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