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Calculatoarele în hainele tale? O piatră de hotar pentru electronice portabile(Computers in your clothes? A milestone for wearable electronics)

cercetătorii de la Universitatea de Stat din Ohio au făcut următorul pas către proiectarea de textile funcționale – haine care adună, stochează sau transmit informații digitale. Cu o dezvoltare ulterioară, tehnologia ar putea duce la cămăși care funcționează ca antene pentru telefonul sau tableta dvs. inteligentă, haine de antrenament care monitorizează nivelul de fitness, echipamente sportive care monitorizează performanța sportivilor, un bandaj care îi spune medicului cât de bine este țesutul sub el vindecare – sau chiar un capac flexibil de material care sesizează activitatea în creier.

Posted: Apr 13, 2016

Computers in your clothes? A milestone for wearable electronics

(Nanowerk News) Researchers who are working to develop wearable electronics have reached a milestone: They are able to embroider circuits into fabric with 0.1 mm precision—the perfect size to integrate electronic components such as sensors and computer memory devices into clothing.
With this advance, the Ohio State University researchers have taken the next step toward the design of functional textiles—clothes that gather, store, or transmit digital information. With further development, the technology could lead to shirts that act as antennas for your smart phone or tablet, workout clothes that monitor your fitness level, sports equipment that monitors athletes’ performance, a bandage that tells your doctor how well the tissue beneath it is healing—or even a flexible fabric cap that senses activity in the brain.
embroidered antennas and circuits
Researchers at The Ohio State University are developing embroidered antennas and circuits with 0.1 mm precision—the perfect size to integrate electronic components such as sensors and computer memory devices into clothing. (Photo: Jo McCulty, The Ohio State University)
That last item is one that John Volakis, director of the ElectroScience Laboratory at Ohio State, and research scientist Asimina Kiourti are investigating. The idea is to make brain implants, which are under development to treat conditions from epilepsy to addiction, more comfortable by eliminating the need for external wiring on the patient’s body.
“A revolution is happening in the textile industry,” said Volakis, who is also the Roy & Lois Chope Chair Professor of Electrical Engineering at Ohio State. “We believe that functional textiles are an enabling technology for communications and sensing—and one day even medical applications like imaging and health monitoring.”
Recently, he and Kiourti refined their patented fabrication method to create prototype wearables at a fraction of the cost and in half the time as they could only two years ago. With new patents pending, they published the new results in the journal IEEE Antennas and Wireless Propagation Letters („Fabrication of Textile Antennas and Circuits With 0.1 mm Precision”).
In Volakis’ lab, the functional textiles, also called “e-textiles,” are created in part on a typical tabletop sewing machine—the kind that fabric artisans and hobbyists might have at home. Like other modern sewing machines, it embroiders thread into fabric automatically based on a pattern loaded via a computer file. The researchers substitute the thread with fine silver metal wires that, once embroidered, feel the same as traditional thread to the touch.
“We started with a technology that is very well known—machine embroidery—and we asked, how can we functionalize embroidered shapes? How do we make them transmit signals at useful frequencies, like for cell phones or health sensors?” Volakis said. “Now, for the first time, we’ve achieved the accuracy of printed metal circuit boards, so our new goal is to take advantage of the precision to incorporate receivers and other electronic components.”
The shape of the embroidery determines the frequency of operation of the antenna or circuit, explained Kiourti.
The shape of one broadband antenna, for instance, consists of more than half a dozen interlocking geometric shapes, each a little bigger than a fingernail, that form an intricate circle a few inches across. Each piece of the circle transmits energy at a different frequency, so that they cover a broad spectrum of energies when working together—hence the “broadband” capability of the antenna for cell phone and internet access.
“Shape determines function,” she said. “And you never really know what shape you will need from one application to the next. So we wanted to have a technology that could embroider any shape for any application.”
The researchers’ initial goal, Kiourti added, was just to increase the precision of the embroidery as much as possible, which necessitated working with fine silver wire. But that created a problem, in that fine wires couldn’t provide as much surface conductivity as thick wires. So they had to find a way to work the fine thread into embroidery densities and shapes that would boost the surface conductivity and, thus, the antenna/sensor performance.
Previously, the researchers had used silver-coated polymer thread with a 0.5-mm diameter, each thread made up of 600 even finer filaments twisted together. The new threads have a 0.1-mm diameter, made with only seven filaments. Each filament is copper at the center, enameled with pure silver.
They purchase the wire by the spool at a cost of 3 cents per foot; Kiourti estimated that embroidering a single broadband antenna like the one mentioned above consumes about 10 feet of thread, for a material cost of around 30 cents per antenna. That’s 24 times less expensive than when Volakis and Kiourti created similar antennas in 2014.
In part, the cost savings comes from using less thread per embroidery. The researchers previously had to stack the thicker thread in two layers, one on top of the other, to make the antenna carry a strong enough electrical signal. But by refining the technique that she and Volakis developed, Kiourti was able to create the new, high-precision antennas in only one embroidered layer of the finer thread. So now the process takes half the time: only about 15 minutes for the broadband antenna mentioned above.
She’s also incorporated some techniques common to microelectronics manufacturing to add parts to embroidered antennas and circuits.
One prototype antenna looks like a spiral and can be embroidered into clothing to improve cell phone signal reception. Another prototype, a stretchable antenna with an integrated RFID (radio-frequency identification) chip embedded in rubber, takes the applications for the technology beyond clothing. (The latter object was part of a study done for a tire manufacturer.)
Yet another circuit resembles the Ohio State Block “O” logo, with non-conductive scarlet and gray thread embroidered among the silver wires “to demonstrate that e-textiles can be both decorative and functional,” Kiourti said.
They may be decorative, but the embroidered antennas and circuits actually work. Tests showed that an embroidered spiral antenna measuring approximately six inches across transmitted signals at frequencies of 1 to 5 GHz with near-perfect efficiency. The performance suggests that the spiral would be well-suited to broadband internet and cellular communication.
In other words, the shirt on your back could help boost the reception of the smart phone or tablet that you’re holding – or send signals to your devices with health or athletic performance data.
Source: Ohio State University

Ștergerea modului de aplicare a suprafețelor superhidrofobe în lumea reală(Clearing the way for real-world applications of superhydrophobic surfaces )

ar progresa în mod semnificativ dezvoltarea materialelor superhidrofobe și transferul lor către produse comerciale, de exemplu în aplicații cu autocurățare și anti-înghețare. ) Testul de abraziune liniar. (B) Pe o suprafață superhidrofobică, o picătură de apă se rotește cu frecare redusă, cauzată de captarea unui strat subțire de aer între rugozitatea suprafeței. (C) Deteriorarea rugozității suprafeței duce la fixarea picăturilor

Posted: Apr 09, 2016

Clearing the way for real-world applications of superhydrophobic surfaces

(Nanowerk News) In their perspective article in the journal Science („Moving superhydrophobic surfaces toward real-world applications”), researchers from Aalto University call for consistent and standardized testing of superhydrophobic, i.e. extremely water-repellent, materials. Agreeing on a unified testing method is needed to allow community-wide comparison between published results. This would significantly progress development of superhydrophobic materials and their transfer to commercial products in, for instance, self-cleaning and anti-icing applications.
superhydrophobic surface
(A) Linear abrasion test. (B) On a superhydrophobic surface a water droplet rolls with low friction, as caused by trapping of a thin air layer between the surface roughness. (C) Damaging the surface roughness leads to droplet pinning. (Image: Juan Li, Aalto University)
Currently, research groups around the world use many different kinds of tests to evaluate the durability and wear of superhydrophobic materials. For example, researchers have used linear abrasion, circular abrasion, sandblasting and water jets in testing the surfaces. However, the results obtained through different methods are not comparable, which makes it hard to find the best materials for applications.
‘We therefore propose that researchers should begin using a standardised method when testing the wear and durability of extremely water-repellent materials. We find that linear abrasion of the surface, for example with sandpaper, would be the best general method. It is important to specify the applied pressure, the abrasion distance and the abradant material to make sure the result is reproducible’, explains Professor Robin Ras.
Benefits of the proposed method include, among other things, the easy availability of the testing materials and the simple test setup.
‘Nevertheless, the wear test alone is not sufficient to determine the robustness of the superhydrophobic surface. The second step is to perform tests with water droplets to measure the water-repelling properties of the surface after wear’, clarifies Tuukka Verho, who is currently preparing his doctoral dissertation.
The superhydrophobicity of a surface is often measured based on the shape of a water droplet on the surface, i.e. how completely the droplet beads up in the surface. However, according to the authors, this so-called static contact angle does not provide enough information about the effects of wear, as water often forms almost spherical droplets even on a damaged surface, but no longer easily slides off the surface. Therefore, the authors encourage to always measure droplet mobility, for example using an inclination test.
The Aalto University researchers wish that their perspective article initiates in the research community a discussion on the evaluation of superhydrophobic surfaces. Even though they propose linear abrasion as a primary test for all superhydrophobic materials, additional application-specific tests may be needed, for instance, to assess the laundering durability of textiles or the weather-durability of outdoor materials.
Source: Aalto University

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SEADAM

cu scopul de a dezvolta o nouă generație de instrumente analitice capabile să detecteze oligoelemente la nivel de subfemtogramă, atât în atmosferă, cât și în fluidele corporale, pe baza know-how-ului consultantului tehnic

SEADM1

Cercetătorii folosesc tipărirea 3D pentru a crea structuri cu chimie activă

O limitare a cercetării este făcut pentru structura pentru imprimare, concentrația de nanoparticule necesare pentru a fi mai mică de 10 la sută din masa totală a structurii. Pentru a avea structura eficientă, ar putea fi necesară o concentrație mai mare, dar în funcție de necesitatea, 10 la suta ar putea fi OK, a spus Harting.
Structura tipărită pentru acest studiu a fost o formă simplă. Valorificând puterea de imprimare 3D, cercetatorii Urmatorul pas va fi de a imprima mai multe forme exotice pentru a înțelege modul în care structura imprimată Afectează reactivitatea chimic

Posted: Apr 01, 2016

Researchers use 3-D printing to create structure with active chemistry

(Nanowerk News) Many materials – sugars, thermoplastics, glass, metals, ceramics and more – are used to produce 3D-printed figures, typically with expensive or custom-built 3D printers.
For the first time, researchers have demonstrated how to use commercial 3D printers to create a structure with active chemistry. Led by Matthew Hartings, American University chemistry professor, researchers created a chemically active 3D-printed structure that acts to mitigate pollution. A study outlining the process published online today in Science and Technology of Advanced Materials („The chemical, mechanical, and physical properties of 3D printed materials composed of TiO2-ABS nanocomposites”).
And it’s OK to try this at home. The experiment, created with many off-the-shelf materials common to makers, hobbyists and home enthusiasts, puts the power of chemistry invention into the hands of people taking advantage of the 3D printing revolution.
The researchers designed a small structure the size of handheld sponge. They dispersed throughout plastic chemically active titanium dioxide (TiO2) nanoparticles. Using the same filament hobbyists use in the printing process of 3D-printed figures, researchers added the nanoparticles. Using a 3D thermoplastic printer, ubiquitous in manufacturing, the researchers printed a small, sponge-like plastic matrix.
Researchers had two questions: Would the nanoparticles stay active in the structure once printed? Created for pollution mitigation, would the matrix perform? The answers were yes.
Pollutants break down when natural light interacts with TiO2, which has potential applications in the removal of pollution from air, water and agricultural sources.
To demonstrate pollution mitigation, they placed the matrix in water and added an organic molecule (pollutant). The pollutant was destroyed. TiO2 also photocatalyzed the degradation of a rhodamine 6G in solution.
„It’s not just pollution, but there are all sorts of other chemical processes that people may be interested in. There are a variety of nanoparticles one could add to a polymer to print,” Hartings said.
One limitation of the research is that for the structure to print, the concentration of nanoparticles needed to be less than 10 percent of total mass of the structure. To have an efficient structure, a higher concentration could be needed, but depending on the need, 10 percent might be OK, Hartings said.
The structure printed for this study was a simple shape. Harnessing the power of 3D-printing, the researchers’ next step will be to print many exotic shapes to understand how printed structure affects the chemical reactivity.
Because of the promising results, they’ve already started experimenting with different printed geometries to determine an optimal printed shape for applications that involve photocatalytic removal of environmental pollutants.
Source: American University

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Dezvoltarea de senzori de imprimare respirație pentru diagnosticarea precoce și monitorizarea bolilor(Development of breath-print sensors for early diagnosis and monitoring of diseases

dezvolta senzori ultrasensitivi si selectivi de gaz pentru a diagnostica bolile prin analiza expirarii respiratiei. Profesorul Kim a condus dezvoltarea matricelor senzorilor de nanofibre pe bază de oxid de metal pe bază de oxid de metal, care sunt optimizate pentru recunoașterea modelului de amprente ale respirației ( Small , ” Detectoarele biomemarkerilor bazate pe nanofibre WO 3, activate de catalizatorul încapsulat de proteine ​​auto-asamblate pe polistiren coloid” ).Platforma senzorilor care utilizează nanofibre de oxid de metal poate fi utilizată atât în ​​domeniul diagnosticării bolilor cât și al controlului calității aerului interior / exterior

Posted: Mar 07, 2016

Development of breath-print sensors for early diagnosis and monitoring of diseases

(Nanowerk News) Professor Il-Doo Kim in the Department of Materials Science and Engineering at KAIST is developing ultrasensitive and highly selective gas sensors to diagnose diseases by exhaled breath analysis. Professor Kim has led the development of semiconductor metal oxide-based nanofiber sensor arrays, which are optimized for pattern recognition of breath prints (Small, „WO3 Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates”).
Demonstration of breath analysis using nanofibers
Demonstration of breath analysis using nanofibers functionalized with various catalysts for pattern recognition of breath components such as hydrogen sulfide, acetone, and methyl mercaptan for diagnosis of diabetes and halitosis.
Human breath contains a number of volatile organic compounds (VOCs). Accurate detection of specific VOCs in exhaled breath can provide essential information for the early diagnosis of diseases. For example, acetone, H2S, ammonia, and toluene can be used to evaluate diabetes, halitosis, kidney malfunction, and lung cancer, respectively, where the diagnosis of these diseases can be achieved by analyzing the concentration of VOCs in exhaled breath, originating from the molecular exchange between lung tissue and blood. Variations in the concentration of the exhaled VOCs that may serve as biomarkers for specific diseases can distinguish healthy people from those who are sick.
The non-invasive diagnosis of various diseases is the key advantage of exhaled breath analysis techniques over other commonly used methods. For example, conventional diagnostic methods such as MRI, CT, blood test, endoscope, and X-ray examination, which are expensive and sometimes painful, are usually implemented in hospitals. However, in the near future, inexpensive and simple diagnoses are expected to detect and examine diseases in the early stages. The use of multi-sensor arrays with nanostructured semiconductor metal oxides is essential for developing inexpensive and simple diagnostic tools by examining the concentration of VOCs in exhaled breath. The research team has been developing an array of breathing sensors consisting of a number of semiconductor metal oxide fibers, which will offer patients a real-time diagnosis of diseases.
The sensor arrays are advantageous in terms of gas adsorption, leading to large resistance changes achieved by high specific surface area and porous nanostructure. In particular, highly selective biomarker sensing was accomplished by functionalization of diverse noble metallic catalysts such as Au, Pt, Pd, and Rh, which are essential to establishing multiple sensor arrays for analysis of breath prints. These sensor arrays can be integrated with portable devices for real-time monitoring of physical conditions.
‘The sensor technology is compatible with various types of smartphones, wearable electronic gadgets, and medical devices’ Professor Kim added.
The sensor platform using metal oxide nanofibers can be utilized both in the field of disease diagnosis and indoor/outdoor air quality control. “We believe that there can be many ways to incorporate our technology based on the particular needs of industries, not just in the field of medical devices, such as detecting hazardous chemicals or gases at manufacturing factories.” Professor Kim said.
Currently, Professor Kim has filed 157 domestic and international patents. In addition, he has completed 4 technology transfers. Some of his patents were also transferred to a MEMS gas sensor company (2015). Moreover, the research team received the Grand Prize (Ph.D. candidate, Seon-Jin Choi) at the ‘9th Samsung Inside Edge Paper Competition’ from Samsung Electro-Mechanics in 2013 and the Silver Award (Ph.D. candidate, Sang-Joon Kim) at the ‘21th Samsung Human Tech Paper Competition’ from Samsung Electronics in 2015. Recently, Prof. Kim received Top Excellence Award in the KAIST EEWS Business Pan Contest 2015 (Development of Exhaled Breath Sensor for Diagnosis of Diabetes Based on Analysis of Acetone Concentration in Human Breath, Jan. 2016).
Source: Korea Advanced Institute of Science and Technology (KAIST)

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Fizicienii primesc un material perfect pentru filtrele de aer

demonstrat că reducerea diametrului fibrelor de la 200 nanometri până la 20 a redus rezistența filtrului la fluxul de aer cu două treimi și acest efect nu mai poate fi explicat prin aerodinamica clasică. Când dimensiunea obstacolului este mai mică decât calea liberă a moleculelor de gaze, metodele standard care estimează rezistența aerodinamică bazată pe teoria continuumului nu mai funcționează. În condiții normale, calea medie liberă a moleculelor de aer produce 65 nanometri.

Posted: Mar 01, 2016

Physicists get a perfect material for air filters

(Nanowerk News) A research team from the Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences have synthesized the material that is perfect for protection of respiratory organs, analytical research and other practical purposes. An almost weightless fabric made of nylon nanofibers with a diameter less than 15 nm beats any other similar materials in terms of filtering and optical properties.
The scientists whose work is published in Macromolecular Nanotechnology Journal („Filtering and optical properties of free standing electrospun nanomats from nylon-4,6”), characterize their material as lightweight (10-20 mg/m2), almost invisible (95% light transmission: more than that of a window glass), showing low resistance to airflow and efficient interception of <1 micrometer fine particulate matter.
An almost weightless fabric made of nylon nanofibers with a diameter less than 15 nm
A sample of the new fabric in reflected light. (Image courtesy of the researchers)
The wording „nanofibers” in the researchers’ article is more than a fashion statement. Previously, the same team demonstrated that reducing fiber diameter from 200 nanometers down to 20 decreased filter resistance to airflow by two thirds, and this effect could no longer be explained by classical aerodynamics. When an obstacle size is smaller than the free path of gas molecules, the standard methods estimating aerodynamic resistance based on the continuum theory no longer work. In normal conditions, the mean free path of air molecules makes 65 nanometers.
The mean free path is the average distance one molecule manages to cover before colliding with another. Only if all obstacles are much bigger than this value, the free stream coming at them can be rightfully considered a continuous medium.
The scientists used the technique called electrospinning: a jet of a dissolved polymer is ejected through a special nozzle aiming at a target under action of an electric field. From the other side, ethanol is electrosprayed. The polymer jet and the alcohol ions take the opposite electric charges. Colliding in the air, they form ultra-thin fibrous films. Electrospinning technology as a way to produce nonwoven fibrous filters has been developed back in the 50s to purify air in atomic industry. However, the researchers introduced an important improvement: instead of obtaining nanomats on a solid conducting substrate like before, now with the new technology, a free filter is formed covering a 55-mm hole in a non-conductive polycarbonate screen.
The published work completed the cycle of the authors’ papers devoted to development of the manufacturing technology and studies of properties of nanofilters manufactured using this new process. It was established that the unique optical and filtering properties originate from a special mechanism of „healing” holes and defects in free standing filters. Such holes literally attract fibers landing onto the filter surface. As a result, a good filter without big holes can be obtained from a minimum amount of nanofibers and, accordingly, with a minimum resistance to airflow. Moreover, active healing of big holes between threads provides the filters with the properties inherent in filters with calibrated pores, so called track-etched membranes (Nuclepores). The scientists have also demonstrated that the „healing” mechanism does not work in the conventional electrospinning technique where nanofibers are deposited onto a conducting substrate completely at random.
The testing of nylon-4,6 electrospun films showed that thess almost weightless and invisible fabrics trap no less than 98% of airborne dust particles. For testing, the scientists used particles from 0.2 to 0.3 micron in diameter. This roughly corresponds to the dust that is not caught by the nasal pharynx, and penetrates the lungs causing a number of dangerous medical conditions. Submicron particles (< 1 micrometer in diameter) are the ones also used to test industrial and medical filters. To assess performance, resistance to airflow is tested as well.
Experiments to measure resistance have been made on singular samples so far. In real filters a multi-layer surface with a complex configuration is normally used. The experiments showed that the nylon-4,6 filtering material had the best properties out of all types of fabric previously described . In terms of interception extent to filter weight ratio and interception-resistance to airflow ratio, the new filtering material beats any existing equivalents by several times.
At first it looks like a ring sitting on a sheet of paper. In reality, it is a sample of the new fabric for filters. The small red spot on top of „l” letter is a spot wherea laser beam penetrates the film. Low intensity of dispersed light demonstrates high transparency of the new material. A transmission index of the new product is higher than that of a good window glass. The picture is courtesy of the researchers.
Speaking about possible applications of this material, the scientists claim it is more than the obvious air and water purification from particulate matter. Since the material surpasses glass in transparency, it can be used in biological research. For example, after pumping air or water through the new filter intercepted microorganisms may be directly observed right on the transparent filter under a microscope. Again, this effect is due to ultra-fine threads. Their thickness is significantly less than even visible light wavelength.
Source: Moscow Institute of Physics and Technology

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