proiectul pentru uniforme avansate a fost extins;Uniforma AMBER este o soluție de generare a cuiburilor care integrează tehnologii, inclusiv rezistența la flacără, protecția împotriva patogenului din sânge, repellența la apă, confort îmbunătățit, tampoane integrate pentru genunchi și vizibilitate ridicată printre alte caracteristici critice
Imaginile geospațiale, recunoașterea facială și alte elemente biometrice determină cercetarea comunității de informații în domeniul inteligenței artificiale;sunt de asemenea domenii în care se așteaptă inovații prin programe academice și de cercetare din industrie
Modular Kit pentru șină atașată Plus Set adaptoare pentru șine Arc Adaptoare: Sistem de montare a căștilor de luptă / tactic pentru protecția activă a auzului tactic
soluție
Proprietățile fotocatalitice ale anatazei, una dintre cele trei forme naturale de dioxid de titan, au fost descoperite în Japonia la sfârșitul anilor ’60. Sub influența radiației UV în lumina soarelui, se pot descompune poluanți organici, cum ar fi bacterii, ciuperci și nicotină, și unele materiale anorganice în dioxid de carbon. Efectul catalitic este cauzat de nanostructura cristalelor sale.
Aplicată în aer liber, acest material accesibil și disponibil pe scară largă ar putea reprezenta o soluție eficientă de autocurățare pentru clădiri. Acest lucru se datorează reacției chimice, care lasă un reziduu pe fațadele clădirilor, un reziduu apoi spălat atunci când plouă. Aplicarea lui la monumentele din zonele urbane poate salva patrimoniul nostru cultural, care este amenințat de poluanți.
Cu toate acestea, „vopselele fotocatalitice și aditivii au fost mult timp o provocare pentru industria de acoperire, deoarece acțiunea catalitică afectează durabilitatea lianților de rășină și oxidează componentele vopselei”, explică Ioannis Arabatzis, fondator și director general al NanoPhos, cu sediul în orașul grecesc din Lavrio, într-una din țările în care se află unele dintre cele mai importante monumente ale istoriei omenirii. Compania greacă testează o vopsea numită Kirei, inspirată de un cuvânt japonez care înseamnă atât curat, cât și frumos.
| Posted: Sep 15, 2017 | |
Nanocoating protects buildings against pollution(Nanowerk News) The organic pollution decomposing properties of titanium dioxide (TiO2) have been known for about half a century. However, practical applications have been few and hard to develop, but now a Greek paint producer claims to have found a solution |
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| The photocatalytic properties of anatase, one of the three naturally occurring forms of titanium dioxide, were discovered in Japan in the late 1960s. Under the influence of the UV-radiation in sunlight, it can decompose organic pollutants such as bacteria, fungi and nicotine, and some inorganic materials into carbon dioxide. The catalytic effect is caused by the nanostructure of its crystals. | |
| Applied outdoors, this affordable and widely available material could represent an efficient self-cleaning solution for buildings. This is due to the chemical reaction, which leaves a residue on building façades, a residue then washed away when it rains. Applying it to monuments in urban areas may save our cultural heritage, which is threatened by pollutants. | |
| However, “photocatalytic paints and additives have long been a challenge for the coating industry, because the catalytic action affects the durability of resin binders and oxidizes the paint components,” explains Ioannis Arabatzis, founder and managing director of NanoPhos, based in the Greek town of Lavrio, in one of the countries home to some of the most important monuments of human history. The Greek company is testing a paint called Kirei, inspired by a Japanese word meaning both clean and beautiful. | |
| According to Arabatzis, it’s an innovative product because it combines the self-cleaning action of photocatalytic nanoparticles and the reflective properties of cool wall paints. “When applied on exterior surfaces this paint can reflect more than 94% of the incident InfraRed radiation (IR), saving energy and reducing costs for heating and cooling”, he says. “The reflection values are enhanced by the self-cleaning ability. Compared to conventional paints, they remain unchanged for longer.” | |
| The development of Kirei has been included in the European project BRESAER, which is studying a sustainable and adaptable “envelope system” to renovate buildings. The new paint was tested and subjected to quality controls following ISO standard procedures at the company’s own facilities and in other independent laboratories. “The lab results from testing in artificial, accelerated weathering conditions are reliable,” Arabatzis claims. “There was no sign of discolouration, chalking, cracking or any other paint defect during 2,000 hours of exposure to the simulated environmental conditions. We expect the coating’s service lifetime to be at least ten years.” | |
| Many studies are being conducted to exploit the properties of titanium dioxide. Jan Duyzer, researcher at the Netherlands Organisation for Applied Scientific Research (TNO) in Utrecht, focused on depollution: “There is no doubt about the ability of anatase to decrease the levels of nitrogen oxides in the air. But in real situations, there are many differences in pollution, wind, light, and temperature. We were commissioned by the Dutch government specifically to find a way to take nitrogen oxides out of the air on roads and in traffic tunnels. We used anatase coated panels. Our results were disappointing, so the government decided to discontinue the research. Furthermore, we still don’t know what caused the difference between lab and life. Our best current hypothesis is that the total surface of the coated panels is very small compared to the large volumes of polluted air passing over them,” he tells youris.com. | |
| “In laboratory conditions the air is blown over the photocatalytic surface with a certain degree of turbulence. This results in the NOx-particles and the photocatalytic material coming into full contact with one another,” says engineer Anne Beeldens, visiting professor at KU Leuven, Belgium. Her experience with photocatalytic TiO2 is also limited to nitrogen dioxide (NOx) pollution. | |
| “In real applications, the air stream at the contact surface becomes laminar. This results in a lower velocity of the air at the surface and a lower depollution rate. Additionally, not all the air will be in contact with the photocatalytic surfaces. To ensure a good working application, the photocatalytic material needs to be positioned so that all the air is in contact with the surface and flows over it in a turbulent manner. This would allow as much of the NOx as possible to be in contact with photocatalytic material. In view of this, a good working application could lead to a reduction of 5 to 10 percent of NOx in the air, which is significant compared to other measures to reduce pollutants.” | |
| The depollution capacity of TiO2 is undisputed, but most applications and tests have only involved specific kinds of substances. More research and measurements are required if we are to benefit more from the precious features of this material. |
| Source: By Koen Mortelmans, Youris |
Spre deosebire de un metal obișnuit, într-un material semi-metalic, electronii cu o singură orientare în rotație – de exemplu, spin-up – participă la curentul electric. În ceea ce privește electronii spin-down, energia lor este prea mare și, prin urmare, nu pot purta curent de încărcare. Aceasta înseamnă că, atunci când curentul trece printr-o jumătate de metal, este generat și un curent polarizat în spin. Dar tronica spin-valley încearcă să manipuleze nu numai o populație de electroni spin-polarizată în actualul dar și așa-numitul index de vale.Pentru un material cu o undă de densitate pentru a deveni o jumătate de metal, este nevoie de un tratament special cunoscut sub numele de dopaj. Aceasta implică încorporarea electronilor sau a găurilor în izolator. Alexandru Rozhkov, co-autor al lucrării și cercetător la Departamentul de Probleme de Fizică și Energetică al MIPT, explică faptul că un sistem poate fi dopat prin supunerea lui la un câmp electric extern sau la modificări chimice de vrac sau de suprafață: „Pentru fiecare sistem , trebuie selectat un tip adecvat de atomi de dopaj – cum ar fi azot, fosfor sau alt element. Prin înlocuirea atomilor din sistemul gazdă cu impuritățile care dau sau acceptă electroni de conducere, este indusă o schimbare a proprietăților materialului original. ”
| Posted: Sep 14, 2017 | |
Physicists predict nonmetallic half-metallicity(Nanowerk News) A team of researchers from the Moscow Institute of Physics and Technology (MIPT) and the Institute for Theoretical and Applied Electrodynamics (ITAE) of the Russian Academy of Sciences (RAS), in collaboration with a colleague from RIKEN (an institute for physical and chemical research in Japan), has provided theoretical proof of the existence of a new class of materials. It was suggested that such systems be referred to as ‘spin-valley half-metals.’ |
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| The paper was published in the journal Physical Review Letters („Spin-Valley Half-Metal as a Prospective Material for Spin Valleytronics”). The discovery will find use in implantable electronics, alongside devices based on graphene, nanotubes, and a number of other promising materials. | |
| The microscopic mechanism proposed by the researchers differs significantly from the usual half-metal model based on a strong electron-electron interaction. This might give rise to a new direction in search for ‘nonmetallic’ half-metals, i.e., those that do not contain atoms of transition metals, such as nickel, manganese, and lanthanum. These would come in handy in implantable devices and systems. The authors use the term ‘spin-valley-tronics’ to refer to the possible alternative to traditional electronics. | |
| Since the invention of the electron tube, the world has seen electronics exhaust most of its possibilities. It would be highly challenging to continue increasing the number of transistors or microprocessor clock rate. That is why researchers around the globe are exploring new possibilities. One of them is spintronics which makes use of electron spins and already has some important practical applications. Around the turn of the century, the use of giant magnetoresistance materials in magnetic field sensors (used to read data in hard disk drives) has enabled the storage of much larger amounts of data on HDDs. | |
| Researchers all over the world are working on new spintronic devices, and half-metals are believed to have great potential. They were first predicted based on computer simulations and later proved to exist experimentally. Unlike a usual metal, in a half-metallic material, electrons of only one spin orientation — e.g., spin up — participate in the electric current. As for spin-down electrons, their energy is too high, and therefore they cannot carry charge current. This means that when the current is passed through a half-metal, a spin-polarized current is generated as well. But spin-valley-tronics seeks to manipulate not only a spin-polarized population of electrons in the current but also the so-called valley index. | |
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| Fig. 1. The term ‘spin’ refers to the intrinsic angular momentum of a particle. The spin of a particle has both a magnitude and a direction. In the case of the electron, the magnitude is 1/2 times Planck’s constant, and the direction is either up or down. (Image: MIPT) | |
| The term ‘valley’ is borrowed from semiconductor physics. Mathematically, the excitation energy in a solid is expressed by E (κ, n), where κ is the momentum of the electron and n is the zone index, i.e., a discrete quantum property of the state of the electron. This function may look rather odd, and in the case of several minimums with comparable excitation energies, one can speak of the presence of multiple ‘valleys’. | |
| With certain reserve, one could say that electrons whose states correspond to one of the valleys do not interact with electrons from another valley. Such an ensemble of electrons can carry not only spin and charge, but also a distinct value called the valley index. | |
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| In the figure, electron and hole energy is plotted against momentum. (The four black curves correspond to two projections of electron spin and two projections of hole spin.) The thick curve corresponds to electron states capable of conducting an electric current (forming a Fermi surface). Depending on the mutual orientation of the spins of electrons (blue arrows) and holes (red arrows) on the Fermi surface, the system is either an ordinary half-metal (c) or a spin-valley half-metal (d). (Image: MIPT) | |
| The valley index can be used to transfer information with the help of valley currents – in this regard, the valley index is quite similar to spin. Research in this direction is currently being carried out by several groups, which implies that the ideas proposed in the publication are not pure abstractions. The idea of using the valley index is certainly not a new one, but what the researchers did is, they theoretically proved the existence of a novel class of materials for use in spin-valley-tronics. | |
So what’s new? |
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| The half-metals available to the researchers all contain atoms of transition metals: nickel, manganese, or lanthanum, etc. The team of researchers, which included physicists from Russia and Japan, has demonstrated a theoretical mechanism for achieving half-metallicity that requires no transition metal atoms. This possibility would have a number of useful applications, including in implantable devices. | |
| The physicists suggest that ‘nonmetallic half-metals’ be obtained from a special class of dielectric materials called charge- or spin-density wave insulators. The term charge- or spin-density wave refers to a state with periodic microscopic regions with nonzero average charge (spin) in the material. Theorists describe such systems as a quantum condensate of electron-hole pairs. For a pair of this kind to form, two valleys are required: One provides electrons, the other provides holes. It is the presence of two valleys in the original system that gives rise to spin-valley half-metallicity. | |
| In semiconductor physics, a ‘hole’ is a quasiparticle that is considered to have a positive charge. | |
| For a material with a density wave to become a half-metal, it requires a special treatment known as doping. This involves the incorporation of electrons or holes into the insulator. Alexander Rozhkov, a co-author of the paper and a researcher at MIPT’s Department of Problems of Physics and Energetics, explains that a system can be doped by subjecting it to an external electric field or chemical modifications of bulk or surface: ‘For each system, a suitable type of doping atoms – such as nitrogen, phosphorus, or some other element – needs to be selected. By replacing atoms of the host system with impurities donating or accepting conduction electrons, a change in the properties of the original material is induced.’ | |
| The possibility of doping materials with density waves has been discussed in the literature for a long time. Thus, among articles cited in the newly published paper are those dating back to 1970s. The systems dealt with by the researchers have been shown to have various phases, including spatially inhomogeneous (for example, states with the so-called electronic phase separation, and the phases with domain walls, often called ‘stripes’). Now, the unexpected discovery of two new phases – regular and spin-valley half-metallicity – has been made. |
| Source: Moscow Institute of Physics and Technology | |
Un material complet opac este iradiat de sus, cu un model specific de undă – cu efectul că undele luminoase din stânga pot trece acum prin material fără nici o obstrucție.
Acest rezultat surprinzător deschide complet noi posibilități pentru camuflajul activ. Ideea poate fi aplicată diferitelor tipuri de valuri, ar trebui să funcționeze cu valuri de sunet la fel de bine ca și cu unde luminoase. Experimentele se află deja în planificare.Dacă acest model corespunde perfect neregularităților interioare ale materialului care de obicei dispersează lumina, atunci proiecția de deasupra poate opri efectiv împrăștierea și un alt fascicul de lumină care călătorește prin material dintr-o parte poate trece fără nici o obstrucție, împrăștiere sau pierderi.
| Posted: Sep 13, 2017 | |
The beam of invisibility(Nanowerk News) How do we make an object invisible? Researchers from TU Wien (Vienna), together with colleagues from Greece and the USA, have now developed a new idea for a cloaking technology. A completely opaque material is irradiated from above with a specific wave pattern – with the effect that light waves from the left can now pass through the material without any obstruction. |
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| This surprising result opens up completely new possibilities for active camouflage. The idea can be applied to different kinds of waves, it should work with sound waves just as well as with light waves. Experiments are already in the planning. | |
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| A material with random irregularities scatters an incident light wave into all directions. | |
Outwitting the Scattering of Light |
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| “Complex materials such as a sugar cube are opaque, because light waves inside them are scattered multiple times”, says Professor Stefan Rotter (TU Wien). “A light wave can enter and exit the object, but will never pass through the medium on a straight line. Instead, it is scattered into all possible directions.” | |
| For years many different attempts have been made to outwit this kind of scattering, creating a “cloak of invisibility”. Special materials have been worked out, for example, which are able to guide light waves around an object. Alternatively, also experiments have been performed with objects that can emit light by themselves. When an electronic display sends out exactly the same light as it absorbs in the back, it can appear invisible, at least when looked at in the right angle. | |
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| The material is irradiated with a specially designed pattern, the wave from the left can pass through the object completely unperturbed. | |
| At TU Wien a more fundamental approach has now been chosen. “We did not want to reroute the light waves, nor did we want to restore them with additional displays. Our goal was to guide the original light wave through the object, as if the object was not there at all”, says Andre Brandstötter, one of the authors of the study („Wave propagation through disordered media without backscattering and intensity variations”). “This sounds strange, but with certain materials and using our special wave technology, it is indeed possible.” | |
The Laser Material |
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| The team at TU Wien has spent years working on optically active materials, which are used for building lasers. To make the laser shine, energy has to be supplied by means of a pump beam. Otherwise, the laser material behaves just like any other material – it absorbs part of the incident light. | |
| “The crucial point is to pump energy into the material in a spatially tailored way such that light is amplified in exactly the right places, while allowing for absorption at other parts of the material”, says Professor Konstantinos Makris from the University of Crete (previously TU Wien). “To achieve this, a beam with exactly the right pattern has to be projected onto the material from above – like from a standard video projector, except with much higher resolution.” | |
| If this pattern perfectly corresponds to the inner irregularities of the material which usually scatter the light, then the projection from above can effectively switch off the scattering, and another beam of light travelling through the material from one side can pass without any obstruction, scattering or loss. | |
| “Mathematically, it is not immediately obvious that it is at all possible to find such a pattern”, says Rotter. “Every object we want to make transparent has to be irradiated with its own specific pattern – depending on the microscopic details of the scattering process inside. The method we developed now allows us to calculate the right pattern for any arbitrary scattering medium.” | |
Light or Sound |
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| Computer simulations have shown that the method works. Now the idea should be confirmed in experiments. Stefan Rotter is confident that this will be successful: “We are already discussing with experimentalists how this could be done. As a first step, we may test this technology with sound instead of light waves. Experimentally, they are easier to handle, and from a mathematical point of view, the difference does not matter significantly.” |
| Source: Vienna University of Technology | |
În funcție de compoziția luminoforului este posibil să se obțină un spectru variabil de strălucire a ceramicii, adică alb, albastru, galben etc. Pentru acest scop, se selectează luminoforele optime în compoziția generală a materialului ceramic transparent”, adaugă Oleg Khasanov.
Sursele de lumină din ceramică luminescente vor avea, de asemenea, o rezistență mai mare. Aceasta înseamnă că sursele de lumină vor dura mult mai mult și vor fi mai greu de deteriorat.
Oamenii de știință de la TPU observă că ceramica din zilele noastre se aplică în diferite domenii: electronică, radioelectronică, industria de apărare, petrol și gaze, industria nucleară, aerospațială, automobile, precum și în domeniul energetic și medicină și în multe alte domenii. Materialele ceramice au un set avansat de proprietăți operaționale: o gamă largă de aplicații (de la temperatura rece la temperatura plasmei în duzele motorului de rachetă), determină rezistența și proprietățile electrofizice.
| Posted: Sep 13, 2017 | |
Luminescent ceramics for new light sources(Nanowerk News) A technology for obtaining luminescent ceramics which may become a cheaper alternative to modern light sources is being developed by scientists of Tomsk Polytechnic University. In the future this kind of ceramics can replace LEDs; its application will make it possible to significantly reduce the cost of production of automobile headlights and other light sources. Another advantage of luminescent ceramics is higher strength due to which ceramic material products will be more durable. |
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| Luminescent ceramics. (Image: TPU) | |
| A research team from the Department of Nanomaterials and Nanotechnology and TPU Nano-Center under the supervision of Professor Oleg Khasanov develops luminescent ceramics. Research is conducted together with the Department of Lasers and Lighting Engineering. | |
| In automobile industry new ceramics can be applied in different lighting devices, for example, in car headlights, and lights for urban and holiday illumination. | |
| „In mass production luminescent nanoceramic light sources cost less compared to modern LEDs with more complex electronic structure,” says Professor Khasanov. | |
| TPU scientists obtain various types of nanoceramics, i.e. luminescent and transparent ceramics, on a spark-plasma sintering unit (SPS) for powder materials. Ceramic powder is placed in a special mold which is conductive and capable to withstand high temperatures and pressure casting. After that, the powder is heated by impulse current at the required temperature and simultaneously compressed. Therefore, sintering lasts quickly. | |
| „Depending on the composition of luminophor it is possible to obtain a variable spectrum of glow of ceramics, i.e. white, blue, yellow, etc. For this purpose we select optimal luminophors in the general composition of transparent ceramic material,” adds Oleg Khasanov. | |
| Light sources made of luminescent ceramics will also feature higher strength. That means, the light sources will last much longer and they will be more difficult to damage. | |
| TPU scientists note that nowadays ceramics is applied in various fields: electronics, radioelectronics, defense industry, oil & gas, nuclear industry, aerospace, automobile, as well as in power engineering and medicine and many other fields. Ceramic materials have an advanced set of operational properties: a wide range of applications (from space cold to plasma temperature in rocket engine nozzles), determined strength and electrophysical properties. |
| Source: Tomsk Polytechnic University | |
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Read more: Luminescent ceramics for new light sources
Elementul galiu joacă un rol central în această nouă clasă de materiale. Galiul se topește la aproximativ 30 ° C și are un punct de fierbere de 2400 ° C. Acesta posedă capacitatea unică de a putea dizolva aproape toate celelalte metale. Când este expus la aer, straturi ultra-subțiri de oxid se formează pe suprafața galiului; totuși, acestea sunt reconvertite înapoi la elementul original în condițiile obținute în timpul multor procese catalitice.
Până în prezent, cercetătorii FAU și-au atins rezultatele spectaculoase utilizând paladiu dizolvat în galiu. În continuare intenționează să efectueze cercetări suplimentare pentru a afla dacă aceste efecte extraordinare pot fi obținute și prin utilizarea metalelor neprețioase dizolvate în galiu și, de asemenea, dacă efectele pot fi reproduse în legătură cu alte reacții chimice.
„Calculele noastre ne determină să presupunem că atomii individuali de metal dizolvați în galiu pot prezenta caracteristici reactive complet diferite de cele pe care le va expune același metal în formă cristalină”, explică Andreas Görling.
„Din acest motiv suntem atât de fascinați de această nouă clasă de materiale catalitice, suntem convinși că, cu ajutorul complexelor de aliaje susținute, pot fi dezvoltați catalizatori foarte eficienți și rentabili, care au un potențial considerabil în ceea ce privește aplicațiile industriale” adaugă Hans-Peter Steinrück.
Read more: Supported liquid metal catalysts – a new generation of reaction accelerators |
au proiectat o alternativă flexibilă și organică la bateriile rigide care alimentează implanturile medicale
În viitor, acest tip de ceramică poate înlocui LED-urile; O tehnologie de obtinere a ceramicii luminiscente, care poate deveni o alternativa mai ieftina la sursele de lumina moderna, este dezvoltata de oamenii de stiinta
Adaptor LightWing Lo-Pro Suport Tactical Light pentru microfon Fusion 2.0 Sistem de montare pentru Tactical AR-15 / M4 / M4A1 Carbine / SBR
