2019-09-12 - Nº 228
Esta é a Newsletter Nº 228 que se apresenta com o mesmo formato que as anteriores. Se gostar da Newsletter partilhe-a!
Todas as Newsletters encontram-se indexadas no link.
Esta Newsletter tem os seguintes tópicos:
Faz hoje anos que nascia, em 1812, Richard March Hoe. Este Inventor americano desenvolveu e fabricou a primeira prensa rotativa de sucesso em 1846. Um cilindro rolou sobre placas fixas com tinta e provoca uma impressão no papel. Isto eliminou a necessidade de fazer impressões directamente das próprias placas, que eram pesadas e difíceis de manobrar. Ao girar constantemente em apenas uma direcção, a impressora rotativa Hoe aumentou o número de páginas que podiam ser impressas por hora.
Faz também anos hoje que nascia, em 1818, Richard Jordan Gatling. Este inventor norte-americano, tem na metralhadora Gatling (1861) a primeira metralhadora bem-sucedida, um desenho com múltiplos canos de accionamento rápido com manivela que combina fiabilidade, alta taxa de disparo e facilidade de carregamento num único dispositivo. O seu pai também foi um inventor e, quando jovem, Richard ajudou-o a criar máquinas para semear e desbaste de algodão. Em 1839, ele projectou uma hélice de parafuso para barcos a vapor, mas descobriu que uma similar já tinha sido patenteada anteriormente. Desde 1844, ele continuou a inventar máquinas agrícolas, incluindo uma para plantar grãos, como arroz e trigo (adaptado da máquina de semear algodão); uma máquina de quebrar o cânhamo (1850); e um arado a vapor (1857). A eclosão da Guerra Civil Americana levou-o a projetar armas de fogo (1861).
Faz igualmente anos hoje que nascia, em 1897 - Irène Joliot-Curie. Esta física francesa, esposa de Frédéric Joliot-Curie, partilhou o Prémio Nobel de Química de 1935 "em reconhecimento à síntese de novos elementos radioactivos". Por exemplo, na suas pesquisas conjuntas, eles descobriram que átomos de alumínio expostos a raios alfa transformavam-se em átomos de fósforo radioactivo. Ela era filha dos vencedores do Prémio Nobel Pierre e Marie Curie. Desde 1946, ela foi directora do Radium Institute, Paris, fundada por sua mãe. Ela morreu de leucemia, como sua mãe, resultante da exposição à radiação durante a pesquisa.
Por fim, faz anos hoje que nascia, em 1900, Haskell Curry. Este matemático norte-americano foi pioneiro da lógica matemática moderna. A sua pesquisa nos fundamentos da matemática levou-o ao desenvolvimento da lógica combinatória. Mais tarde, este trabalho seminal encontrou aplicação significativa na ciência da computação, especialmente no desenho de linguagens de programação. Curry trabalhou no primeiro computador electrónico, chamado ENIAC, durante a Segunda Guerra Mundial. Ele também formulou um cálculo lógico usando regras inferenciais. Em 1942, ele publicou o paradoxo de Curry, que ocorre na teoria dos conjuntos ou na lógica ingénua, e permite a derivação de uma sentença arbitrária de uma sentença auto-referente e de algumas regras de dedução lógica aparentemente inócuas.
Nesta semana que passou ficámos a saber que os planos da Índia de ser a 5a potência a colocar um objecto feito pelo Homem na Lua falharam. Embora a sonda Vikram tenha aterrado na superfície lunar, não foi até ao momento possível estabelecer contacto com a mesma. De acordo com a Agência Espacial Indiana, ISRO, a descida da sonda prosseguiu normalmente até uma altitude de 2,1 km acima da Lua. Após esse período, a comunicação foi perdida com a nave-espacial. Os dados da descida serão analisados para avaliar melhor o que de errado aconteceu com a tentativa de aterragem.
Também esta semana que passou foi anunciado que o investigador matemático Drew Sutherland ajudou a resolver o quebra-cabeça de soma de três cubos há décadas, com a ajuda do "The Hitchhiker's Guide to the Galaxy.". Uma equipa liderada por Andrew Sutherland, do MIT, e Andrew Booker, da Universidade de Bristol, resolveu a peça final de um famoso quebra-cabeça de matemática de 65 anos com uma resposta para o número mais esquivo de todos: 42.
O número 42 é especialmente importante para os fãs do "The Hitchhiker's Guide to the Galaxy", do escritor Douglas Adams, porque esse número é a resposta dada por um supercomputador à "Questão Final da Vida, do Universo e de Tudo". Booker também queria saber a resposta para 42. Ou seja, existem três cubos cuja soma é 42? Esta soma de três cubos, iniciada em 1954 na Universidade de Cambridge e conhecida como Equação Diofantina x^3 + y^3 + z^3 = k, desafiou os matemáticos a encontrar soluções para os números de 1 a 100. Com números menores, esse tipo de equação é mais fácil de resolver: por exemplo, 29 podem ser escritos como 33 + 13 + 13, enquanto 32 é insolúvel. Todos foram finalmente resolvidos, ou provados insolúveis, usando várias técnicas e supercomputadores, excepto por dois números: 33 e 42. Foi através do uso da rede Charity Engine que Sutherland e Booker executaram os cálculos por vários meses, mas a execução final bem-sucedida foi concluída à apenas algumas semanas. Quando o email do Charity Engine chegou, ele forneceu a primeira solução para x^3 + y^3 + z^3 = 42:
42 = (-80538738812075974)^3 + 80435758145817515^3 + 12602123297335631^3
Na Newsletter desta semana apresentamos diversos projetos de maker. É apresentado também um livro sobre "Competitive Programmer".
João Alves ([email protected])
O conteúdo da Newsletter encontra-se sob a licença Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Novidades da Semana
"4:45pm ET Update: According to the Indian Space Agency, ISRO, the lander's descent proceeded normally until an altitude of 2.1km above the Moon. After this time communication was lost with the spacecraft. Data from the descent will be analyzed to further assess what went wrong with the landing attempt. Original post: In late July, an Indian rocket launched the Chandrayaan-2 mission from a spaceport in the Bay of Bengal. This is the second spacecraft India has sent to the Moon and the first to attempt a soft landing. Since launching, the Chandrayaan-2 spacecraft has spent the last six weeks spiraling toward lunar orbit, reaching it, and releasing a lander that will attempt to reach the surface." [...]
"Most development work on self-driving cars focuses on mundane things like getting around parked cars and keeping bugs off sensors, but what about speed? Roborace is trying to develop a racing series for autonomous cars, and has set a Guinness World Record for the world’s fastest self-driving car at 175.49 mph. Roborace’s autonomous race car, dubbed Robocar, made its record runs at Elvington Airfield in the United Kingdom, with Guinness adjudicators on hand. The attempt was made in March, but an official announcement was postponed to coincide with the publication of Guinness’ 2020 record book. Because there was no existing self-driving car top speed record to aim for, Guinness set 160 mph as the unofficial record the Robocar needed to beat. As is standard procedure for top-speed records, officials took the average of runs in opposite directions to come up with the final number." [...]
"Today, Intel, the Texas Advanced Computing Center (TACC) at The University of Texas at Austin (UT Austin), the National Science Foundation (NSF), Dell Technologies and other science and technology partners gathered to unveil Frontera, the fifth most powerful supercomputer in the world and the fastest in academia. Based on 2nd generation Intel® Xeon® Scalable processors and featuring Intel® Optane™ DC persistent memory, the Frontera system is poised to accelerate scientific research and innovation. “The Frontera system will provide researchers computational and artificial intelligence capabilities that have not existed before for academic research. With Intel technology, this new supercomputer opens up new possibilities in science and engineering to advance research including cosmic understanding, medical cures and energy needs.” –Trish Damkroger, Intel vice president and general manager, Extreme Computing Organization Why It’s Important: As the world’s fastest academic supercomputer, Frontera will enable breakthrough research across a number of fields, including astronomy, medicine, artificial intelligence (AI), quantum mechanics and mechanical engineering. Early projects being run on Frontera include: Understanding the influence of distant stars: Manuela Campanelli, professor of astrophysics at Rochester Institute of Technology and director for the Center for Computational Relativity and Gravitation, is using Frontera to develop a simulation to amplify our understanding of gravitational waves. The goal is to explain the origin of the powerful energy bursts that are emitted during a neutron star merger, including the types of electromagnetic signals emitted." [...]
Ciência e Tecnologia
"Mathematics researcher Drew Sutherland helps solve decades-old sum-of-three-cubes puzzle, with help from "The Hitchhiker's Guide to the Galaxy." A team led by Andrew Sutherland of MIT and Andrew Booker of Bristol University has solved the final piece of a famous 65-year old math puzzle with an answer for the most elusive number of all: 42. The number 42 is especially significant to fans of science fiction novelist Douglas Adams’ “The Hitchhiker’s Guide to the Galaxy,” because that number is the answer given by a supercomputer to “the Ultimate Question of Life, the Universe, and Everything.” Booker also wanted to know the answer to 42. That is, are there three cubes whose sum is 42? This sum of three cubes puzzle, first set in 1954 at the University of Cambridge and known as the Diophantine Equation x3+y3+z3=k, challenged mathematicians to find solutions for numbers 1-100. With smaller numbers, this type of equation is easier to solve: for example, 29 could be written as 33 + 13 + 13, while 32 is unsolvable." [...]
"Göttingen researchers develop a new method allowing ten-fold improvement in optical resolution Researchers at the University of Göttingen have developed a new method that takes advantage of the unusual properties of graphene to electromagnetically interact with fluorescing (light-emitting) molecules. This method allows scientists to optically measure extremely small distances, in the order of 1 ångström (one ten-billionth of a meter) with high accuracy and reproducibility for the first time. This enabled researchers to optically measure the thickness of lipid bilayers, the stuff that makes the membranes of all living cells. The results were published in Nature Photonics. Researchers from the University of Göttingen led by Professor Enderlein used a single sheet of graphene, just one atom thick (0.34 nm), to modulate the emission of light-emitting (fluorescent) molecules when they came close to the graphene sheet. The excellent optical transparency of graphene and its capability to modulate through space the molecules’ emission made it an extremely sensitive tool for measuring the distance of single molecules from the graphene sheet." [...]
"Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a new type of sensor that uses atoms to receive commonly used communications signals. This atom-based receiver has the potential to be smaller and work better in noisy environments than conventional radio receivers, among other possible advantages. The NIST team used cesium atoms to receive digital bits (1s and 0s) in the most common communications format, which is used in cell phones, Wi-Fi and satellite TV, for example. In this format, called phase shifting or phase modulation, radio signals or other electromagnetic waves are shifted relative to one another over time. The information (or data) is encoded in this modulation. “The point is to demonstrate one can use atoms to receive modulated signals,” project leader Chris Holloway said." [...]
"In power electronics, semiconductors are based on the element silicon – but the energy efficiency of silicon carbide would be much higher. Physicists of the University of Basel, the Paul Scherrer Institute and ABB explain what exactly is preventing the use of this combination of silicon and carbon in the scientific journal Applied Physics Letters. Energy consumption is growing across the globe; electric power is being relied upon more and more, and sustainable energy supplies such as wind and solar power are becoming increasingly important. Electric power, however, is often generated a long distance away from the consumer. Efficient distribution and transport systems are thus just as crucial as transformer stations and power converters that turn the generated direct current into alternating current. Huge savings are possible Modern power electronics must be able to handle large currents and high voltages." [...]
Future of LEDs Gets Boost from Verification of Localization States Within Indium Gallium Nitride Quantum Wells
"Light-emitting diodes made of indium gallium nitride provide better luminescence efficiency than many of the other materials used to create blue and green LEDs. But a big challenge of working with InGaN is the material is known for dislocation density defects that make it difficult to understand its emission properties. In the Journal of Applied Physics, from AIP Publishing, researchers in China report an InGaN LED structure with high luminescence efficiency and what is believed to be the first direct observation of transition carriers between different localization states within InGaN. The localization states were confirmed by temperature-dependent photoluminescence and excitation power-dependent photoluminescence. Localization states theory is commonly used to explain the high luminescence efficiency gained via the large number of dislocations within InGaN materials. Localization states are the energy minima states believed to exist within the InGaN quantum well region (discrete energy values), but a direct observation of localization states was elusive until now." [...]
"Superconductivity enables us to prevent loss when transporting energy from power plants to our homes. However, to do this, the lines must be cooled to temperatures that are so low as to make large-scale use of superconductors uneconomic at present. Therefore, in laboratories across the world researchers are looking for new superconductive materials that function at less prohibitive temperatures. Great hope rests on so-called cuprates, copper and oxygen based compounds also called high-temperature superconductors, where the scientific community is focusing its efforts. An experiment conducted at the ESRF (European Synchrotron Radiation Facility), the European source of synchrotron-generated light, in Grenoble, coordinated by the Department of Physics at the Politecnico di Milano, with researchers from the Spin Institute from the National Research Council, Sapienza Università di Roma and the Chalmers University of Technology in Gothenburg, has revealed a new property of these materials: the presence of a variety of charge density waves called dynamical charge density fluctuations. The study has been published in Science." [...]
"Scientists at Nanyang Technological University, Singapore (NTU Singapore) have developed a new way to measure distances at the nanoscale – one nanometre being one billionth of a metre – using light. Devices that use light to see objects, such as microscopes, have a fundamental limitation based on the laws of physics, which is their resolving power. The smallest distance that optical devices can reliably image is equal to half the wavelength of the light used, known as the “diffraction limit”. The diffraction limit is therefore above 400 nanometres, about half the wavelength of near infrared light. This is some 250 times smaller than the width of a human hair (100 microns). But since scientists are interested in observing extremely small objects like viruses and nanoparticles that range in size from 10 to 100 nanometres, an optical resolution of 400 nanometres is insufficient." [...]
"Whether for the car or the drone: Developing image processing software for embedded systems takes a lot of time and is therefore very expensive. Now the Tulipp platform makes it possible to develop energy-efficient embedded image processing systems more quickly and less expensively, with a drastic reduction in time-to-market. The Fraunhofer Institute for Optronics, System Technologies and Image Exploitation IOSB is a member of the EU consortium which simplified the process. At first glance drones, driver assistance systems and mobile medical diagnostic equipment don’t appear to have much in common. But in reality they do: they all make increasing use of image processing components, for example for detecting obstacles and pedestrians. Image processing can also be used with mobile X-ray equipment to ensure adequate image quality at reduced radiation levels, thus considerably reducing radioactive exposure." [...]
"Researchers at KU Leuven and imec have successfully developed a new technique to insulate microchips. The technique uses metal-organic frameworks, a new type of materials consisting of structured nanopores. In the long term, this method can be used for the development of even smaller and more powerful chips that consume less energy. The team has received an ERC Proof of Concept grant to further their research. Computer chips are getting increasingly smaller. That’s not new: Gordon Moore, one of the founders of chip manufacturer Intel, already predicted it in 1965." [...]
"An HZB team has for the first time precisely analysed how nanoparticles of lithium sulphide and sulphur precipitate onto battery electrodes during the course of the charging cycle. The results can help increase the service life of lithium-sulphur batteries. Lithium-sulphur batteries are regarded as one of the most promising candidates for the next generation of energy storage devices. They have a theoretical gravimetric energy density that is five times higher than that of the best lithium-ion batteries currently available. And they even work at sub-zero temperatures of down to -50 °C. In addition, sulphur is inexpensive and environmentally friendly." [...]
"Sacrificial ink-writing technique allows 3D printing of large, vascularized human organ building blocks 20 people die every day waiting for an organ transplant in the United States, and while more than 30,000 transplants are now performed annually, there are over 113,000 patients currently on organ waitlists. Artificially grown human organs are seen by many as the “holy grail” for resolving this organ shortage, and advances in 3D printing have led to a boom in using that technique to build living tissue constructs in the shape of human organs. However, all 3D-printed human tissues to date lack the cellular density and organ-level functions required for them to be used in organ repair and replacement. Now, a new technique called SWIFT (sacrificial writing into functional tissue) created by researchers from Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS), overcomes that major hurdle by 3D printing vascular channels into living matrices composed of stem-cell-derived organ building blocks (OBBs), yielding viable, organ-specific tissues with high cell density and function. The research is reported in Science Advances. “This is an entirely new paradigm for tissue fabrication,” said co-first author Mark Skylar-Scott, Ph.D., a Research Associate at the Wyss Institute." [...]
"Secret quantum alphabets could revolutionise how secure communication networks are built and utilised, according to a University of Queensland researcher. UQ PhD candidate and experimental physicist Michael Kewming created his own unique quantum alphabet using the shape of light’s smallest particles – photons. Mr Kewming said communication using single photons gives researchers the ability to encode and send hidden messages using the principles of quantum mechanics. “We tailor the shape of single photons to exploit their quantum mechanical properties, which allows us to do very strange things that you can’t do with classical communication,” Mr Kewming said. “In fact, using these quantum alphabets we recently showed that you can conceal two messages in a single photon. “Imagine this; you’re about sit an exam and you’re allowed to bring one page of study notes." [...]
"Computer Science and Artificial Intelligence Laboratory team creates new reprogrammable ink that lets objects change colors using light. The color-changing capabilities of chameleons have long bewildered willing observers. The philosopher Aristotle himself was long mystified by these adaptive creatures. But while humans can’t yet camouflage much beyond a green outfit to match grass, inanimate objects are another story. A team from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) has brought us closer to this chameleon reality, by way of a new system that uses reprogrammable ink to let objects change colors when exposed to ultraviolet (UV) and visible light sources. Dubbed “PhotoChromeleon,” the system uses a mix of photochromic dyes that can be sprayed or painted onto the surface of any object to change its color — a fully reversible process that can be repeated infinitely." [...]
"The growing popularity of lithium-ion batteries in recent years has put a strain on the world’s supply of cobalt and nickel – two metals integral to current battery designs – and sent prices surging. In a bid to develop alternative designs for lithium-based batteries with less reliance on those scarce metals, researchers at the Georgia Institute of Technology have developed a promising new cathode and electrolyte system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte. “Electrodes made from transition metal fluorides have long shown stability problems and rapid failure, leading to significant skepticism about their ability to be used in next generation batteries,” said Gleb Yushin, a professor in Georgia Tech’s School of Materials Science and Engineering. “But we’ve shown that when used with a solid polymer electrolyte, the metal fluorides show remarkable stability – even at higher temperatures – which could eventually lead to safer, lighter and cheaper lithium-ion batteries.” In a typical lithium-ion battery, energy is released during the transfer of lithium ions between two electrodes – an anode and a cathode, with a cathode typically comprising lithium and transition metals such as cobalt, nickel and manganese. The ions flow between the electrodes through a liquid electrolyte. For the study, which was published Sept. 9 in the journal Nature Materials and sponsored by the Army Research Office, the research team fabricated a new type of cathode from iron fluoride active material and a solid polymer electrolyte nanocomposite." [...]
"Certain materials, like copper, conduct electricity very well. Other materials, like glass, do not. A certain kind of material, called a topological insulator, acts partially like one and partially like the other ― it behaves like a conductor at its surface and an insulator in its interior. Because of topological insulators’ unique electronic properties and their potential use in spintronic devices and even conceivably as transistors for quantum computers, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are interested in investigating the special relationship between two properties of the conducting surface electrons in these materials. “It really gives us a look under the hood,” ― Olle Heinonen, Argonne materials scientist In topological insulators, the spin and momentum of each surface electrons are so closely tied that, in scientific parlance, they are locked to one another. “Spin-momentum locking is like having a basketball that must rotate in a specific direction depending on its trajectory down the court,” said Argonne materials scientist Olle Heinonen." [...]
"Filaments with embedded circuitry can be used to print complex shapes for biomedical and robotic devices. A new method developed by MIT researchers uses standard 3-D printers to produce functioning devices with the electronics already embedded inside. The devices are made of fibers containing multiple interconnected materials, which can light up, sense their surroundings, store energy, or perform other actions. The new 3-D printing method is described in the journal Nature Communication, in a paper by MIT doctoral student Gabriel Loke, professors John Joannopoulos and Yoel Fink, and four others at MIT and elsewhere. The system makes use of conventional 3-D printers outfitted with a special nozzle and a new kind of filament to replace the usual single-material polymer filament, which typically gets fully melted before it’s extruded from the printer’s nozzle. The researchers’ new filament has a complex internal structure made up of different materials arranged in a precise configuration, and is surrounded by polymer cladding on the outside." [...]
"In a paper in Science Robotics, materials scientists from the UCLA Samueli School of Engineering describe a new design for a swimming robot that’s both powered and steered by constant light. The device, called OsciBot because it moves by oscillating its tail, could eventually lead to designs for oceangoing robots and autonomous ships. Its design is inspired by a natural phenomenon called phototaxis — movement toward or away from a light source — that is found throughout the animal kingdom. Both jellyfish and moths, for example, are attracted to light. OsciBot demonstrates that moving by oscillation can be directly powered constant light, rather than relying on light energy that has been harvested and stored in a battery. It’s made entirely of a soft material called a hydrogel that swells when placed in water and is responsive to light." [...]
"EPFL scientists have shown how light inside optical on-chip microresonators can be crystallized in a form of periodic pulse trains that can boost the performance of optical communication links or endow ultrafast LiDAR with sub-micron precision. Optical microresonators convert laser light into ultrashort pulses travelling around the resonator’s circumference. These pulses, called “dissipative Kerr solitons”, can propagate in the microresonator maintaining their shape. When solitons exit the microresonator, the output light takes the form of a pulse train – a series of repeating pulses with fixed intervals. In this case, the repetition rate of the pulses is determined by the microresonator size. Smaller sizes enable pulse trains with high repetition rates, reaching hundreds of gigahertz in frequency." [...]
"Want to make a super strong material from nano-scale building blocks? Start with the highest quality building blocks, right? Wrong — at least when working with “flakes” of graphene oxide (GO). A new study from Northwestern University researchers shows that better GO “paper” can be made by mixing strong, solid GO flakes with weak, porous GO flakes. The finding will aid the production of higher quality GO materials, and it sheds light on a general problem in materials engineering: how to build a nano-scale material into a macroscopic material without losing its desirable properties. “To put it in human terms, collaboration is very important,” said Jiaxing Huang, Northwestern Engineering professor of materials science and engineering, who led the study." [...]
"Medical implants of the future may feature reconfigurable electronic platforms that can morph in shape and size dynamically as bodies change or transform to relocate from one area to monitor another within our bodies. In Applied Physics Letters, from AIP Publishing, a group of researchers from King Abdullah University of Science and Technology and University of California, Berkeley reports a silicon honeycomb-serpentine reconfigurable electronic platform that can dynamically morph into three different shapes: quatrefoils (four lobes), stars and irregular ones. “Quatrefoils can be used for rectangular object-based operation, while stars are for more intricate architectures, and irregular-shaped ones are specifically for implanted bioelectronics,” said Muhammad Hussain, co-author and a visiting professor at the University of California, Berkeley. With their work, the researchers are introducing a new branch of flexible, stretchable electronics — opening the door to new engineering challenges and providing opportunities for innovation in biomedical technologies that can be used for drug delivery, health monitoring, diagnosis, therapeutic healing, implants and soft robotics. Inspiration for the group’s honeycomb-shaped platform comes from nature. “Think of how flowers bloom." [...]
"· Discovery by University of Warwick scientists challenges accepted rule of organic solar cell design · Could help to bring about low cost, flexible and stable organic solar cells for use on vehicles, curved surfaces and windows · Reducing surface area of electrodes in organic solar cells doesn’t reduce performance, provided the conductive parts are close enough together · Composites of insulating polymers and conducting nanoparticles could offer advantages over limited range of materials currently used Solar cells that use mixtures of organic molecules to absorb sunlight and convert it to electricity, that can be applied to curved surfaces such as the body of a car, could be a step closer thanks to a discovery that challenges conventional thinking about one of the key components of these devices. A basic organic solar cell consists of a thin film of organic semiconductors sandwiched between two electrodes which extract charges generated in the organic semiconductor layer to the external circuit. It has long been assumed that 100% of the surface of each electrode should be electrically conductive to maximise the efficiency of charge extraction. Scientists at the University of Warwick have discovered that the electrodes in organic solar cells actually only need ~1% of their surface area to be electrically conductive to be fully effective, which opens the door to using a range of composite materials at the interface between the electrodes and the light harvesting organic semiconductor layers to improve device performance and reduce cost. The discovery, published today (11 September), is reported in Advanced Functional Materials. The academic lead, Dr Ross Hatton from the University’s Department of Chemistry, said: “It’s widely assumed that if you want to optimise the performance of organic solar cells you need to maximize the area of the interface between the electrodes and the organic semiconductors." [...]
"Researchers from Chalmers University of Technology have demonstrated a detector made from graphene that could revolutionize the sensors used in next-generation space telescopes. The findings were recently published in the scientific journal Nature Astronomy. Beyond superconductors, there are few materials that can fulfill the requirements needed for making ultra-sensitive and fast terahertz (THz) detectors for astronomy. Chalmers researchers have shown that engineered graphene adds a new material paradigm for THz heterodyne detection. “Graphene might be the only known material that remains an excellent conductor of electricity/heat even when having, effectively, no electrons. We have reached a near zero-electron scenario in graphene, also called Dirac point, by assembling electron-accepting molecules on its surface." [...]
"Scientists of Tomsk Polytechnic University jointly with Russian and international colleagues developed the concept for constructing an “optical vacuum cleaner”. Due to its optical properties, it can trap nanoparticles from the environment. Currently, there are no effective devices for this task. The research results were published in Scientific Reports (IF:4,525; Q1). In the future, such “vacuum cleaners” can be utilized for air purification during lab-on-a-chip operations and preparation of clean rooms. “The size of nanoparticles varies from 1 to a maximum of 100 nanometers." [...]
"A promising semiconductor material could be improved if flaws previously thought irrelevant to performance are reduced, according to research published today in Nature Communications. A group of researchers at Rensselaer Polytechnic Institute and other universities has shown that a specific defect impacts the ability of halide perovskite to hold energy derived from light in the form of electrons. “Defects could be good or bad in semiconductors,” said Jian Shi, associate professor of materials science engineering. “For some reason, people did not pay attention to dislocations in halide perovskite, but we have shown that this defect is a problem in halide perovskite.” Research on halide perovskite has rapidly improved the efficiency of the material from about a 3% conversion of light to electrical energy to 25% — equivalent to state-of-the-art silicon solar cells — over the course of a decade. Researchers wrestled with silicon for decades to reach that material’s current level of efficiency. Halide perovskite also has promising carrier dynamics, which are roughly defined as the length of time that light energy absorbed by the material is retained in the form of an excited electron." [...]
"A bio-inspired bot uses water from the environment to create a gas and launch itself from the water’s surface. The robot, which can travel 26 metres through the air after take-off, could be used to collect water samples in hazardous and cluttered environments, such as during flooding or when monitoring ocean pollution. Robots that can transition from water to air are desirable in these situations, but the launch requires a lot of power, which has been difficult to achieve in small robots. Now, researchers at Imperial College London have invented a system that requires just 0.2 grams of calcium carbide powder in a combustion chamber. The only moving part is a small pump that brings in water from the environment the robot is sat in, such as a lake or ocean. The water and the calcium-carbide powder then combine in a reaction chamber, producing a burnable acetylene gas." [...]
"The University’s Stephenson Institute for Renewable Energy is part of a new research consortium that has been awarded £11.2 million by the Faraday Institution to explore and develop new materials for next-generation lithium batteries that can be used for electric vehicles. The research aims to deliver improvements in the cost, performance and range of batteries used in electric vehicles, helping pave the way for zero emission transport. The funding from the Faraday Institution will support a four-year project entitled Next Generation Lithium-Ion Cathode Materials (CATMAT) to carry out research on new positive electrodes (cathodes) for battery technologies, similar to those that have helped to power the worldwide portable revolution in mobile phones, and laptop and tablet computers. Current batteries contain cobalt, and there is a need to eliminate or greatly reduce the need for cobalt, which has significant cost, ethical and environmental issues. The new project will aim to transform fundamental understanding of novel cathodes that currently prevent the use of nickel-rich cathode materials (with low or no cobalt) and lithium-rich cathodes. The University’s Stephenson Institute for Renewable Energy is a specialist energy materials research centre which focuses on the physics and chemistry that will transform the future of energy generation, storage, transmission and energy efficiency." [...]
A documentação é parte essencial do processo de aprendizagem e a Internet além de artigos interessantes de explorar também tem alguma documentação em formato PDF interessante de ler. Todos os links aqui apresentados são para conteúdo disponibilizado livremente pelo editor do livro.
"The purpose of this book is to give you a thorough introduction to competitive programming. It is assumed that you already know the basics of programming, but no previous background in competitive programming is needed. The book is especially intended for students who want to learn algorithms and possibly participate in the International Olympiad in Informatics (IOI) or in the International Collegiate Programming Contest (ICPC). Of course, the book is also suitable for anybody else interested in competitive programming. It takes a long time to become a good competitive programmer, but it is also an opportunity to learn a lot. You can be sure that you will get a good general understanding of algorithms if you spend time reading the book, solving problems and taking part in contests." [...]
Diversos Projetos interessantes.
"I have been reading about DIY touch screen table projects for a while now, and I find most of them very complicated. Often They imply using a videoprojector, reflection mirror and IR camera. The result gives you a complete multi touch screen solution, but you need some depth for the videoprojector to have a big screen. Not the best solution for a coffee table... I made this tutorial to help people to build their own touch screen solution based on any flat screen TV. It uses light triangulation technology to read the coordinates." [...]
"I designed a PCB that uses a Teensy, an LCD screen, joystick, buttons, battery and speaker to create a GameBoy-like gaming system! Berry Racer is a game that I came up with and programmed using Arduino's software. The game is run on a Teensy microcontroller which is connected through a custom PCB (Printed Circuit Board) to a screen, a joystick, four buttons, and a piezo speaker. The board can be powered through the micro USB port on the Teensy or with a battery that can be plugged into the back of the PCB, there is also a switch to turn the circuit off when running on battery power. This device and program was designed and built by me with the help of Zane Cochran who was the instructor of the CRT 420 - Special Topics Course at Berry College for the Creative Technologies major. This tutorial will go into detail about how to build a GamePad like this one, however, I hope it is also helpful in case you want to build something slightly different." [...]
"Brief Abstract about my project:- A CNC machine or computer numeric machine is designed to control various machinery functions using computer programs. In this project, the machine is made such that the code made for it can be used to draw the outcome of that code. This concept is used to make logos, drawings and other artwork in real less time. Portraits and sketches can be made like as of an artist's masterpiece. All we have to do is make a code of that picture. Yes!" [...]
"I made the King of Darkness EVIL’s hand. The way of lighting changes depending on the movement of the motion sensor. “King of Darkness” EVIL is a professional wrestler in New Japan Professional Wrestling. He emits evil rays from his hand. " [...]
"Today we will see how to build this awesome TETRIS game made with arduino. The project also has sounds as for example the tetris theme and other beeps and you could add any other sound to the SD card inside the DFplayer module. To create the matrix I've used the well known WS2812 LED addressable strip with RGB LEDs. So with only 1 wire we could control all LEDs and all colors. The code I've used is based on this original file from MarginallyCleve on GitHub. But I've placed new parts such as two 7 segments modules to print the score and top score." [...]
"It's a little interface to use a BLTouch for autoleveling on a GRBL based CNC machine. This Z touch probe is actually meant to be used for autoleveling the print bed on a 3D printer. But because the machine table of my DIY CNC is not perfectly even, I wanted to use it for autoleveling on non-conductive surfaces, like acrylic. For conductive surfaces, you can just clip a crocodile clip to the milling bit and one to the material and as soon as the bit touches the surface, that completes the circuit which will trigger the probe input. So the BLTouch is not needed in this case. The probe is simply controlled, by sending pulses of different widths." [...]
"How to integrate DesignStart Arm Cortex-M1 and M3 processors with the Xilinx Zynq. Introduction Several times this year I have presented courses in person or online about how to implement the Arm DesignStart FPGA cores in Xilinx FPGAs. I have also showcased several projects here on Hackster in which the Arm Cortex-M1 and M3 cores are integrated on Digilient Arty A7 and Arty S7 boards. I thought it would be very useful to show how these cores can be implemented with the Arty Z7. As the Arty Z7 already has dual hard core Arm Cortex-A9 cores this means we are adding another core into an already heterogeneous processing system. What this provides however is an system in which the higher performance processor in this case the A9 can off load sensor interfacing or actuator / motor control to a the M1 or M3." [...]
"Today Im discussing a mechatronics project. This project is actually a derivation of a video I've already posted here: ROUTER AND PLOTTER WIFI WITH WEBSERVER IN ESP32. I advise you to watch this one first, as it explains how the GRBL program works. This video here discusses a ROBOT OF DESIGN, which is already frequently discussed about on the internet. Ill introduce today the assembly of a CNC machine for pen drawings. " [...]
"The 50th anniversary of the Apollo mission brought around lots of projects and talks about the technology that made the mission possible. One item that always fascinated me is "magnetic core memory", a type of RAM made of tiny ferrite beads that store a bit by being magnetized in one direction or another. A close relative of "magnetic core memory" is "core rope memory" which, instead, is a ROM. I started to experiment with a toroid core I had in my parts bin and, after a bit of fumbling, came up with a single bit that could be driven directly by a microcontroller, whithout additional driver circuitry. Let's be clear, this is a bit stretching things as the drive line is a dead short to ground and relies solely on the current limiation of your microcontroller output circuitry. While this might not be best practice, and it surely isn't, it works beautifully at least on the Atmega 328." [...]
"Recently after automating many of my lights with motion sensors (guide coming soon!) I found myself wanting a way to automatically switch everything off at night. The question was how to properly determine when my partner and I had went to bed for the night? I started researching bed occupancy sensors and came across a great post from Zack at Self Hosted Home where he used an ESP8266, 4 load cells and a HX711 to build what is essentially a bed size weight scale to determine if someone was in bed or not. However when I set about building this, I ran into a few issues that required my setup to be different: How to connect 3 wire load cells, there are a lot of cheap 3 wire sensors out there but much of the documentation is for a proper 4 wire setup. Although to be clear, the post above does use a 3 wire setup also." [...]
"An LED counter for tracking your WordPress blog visitors when using the WP Statistics plugin and a Particle Photon. " [...]
"Today I am going to make police strobe light circuit using LM555 IC. Let's get started," [...]
"There are two ways to make the ESP32 GPIO stay at 0 or 1. You can call the #digitalwrite function, or you can go straight to the recorder. Im showing the second option today: how to go straight to the register and write in the memory. This way, the command will instantly change state. Thus, well first learn how to modify multiple GPIOs at once by using bitmasks. In our example today, we used five leds." [...]
_"Here is a unique element for you to add to your astronaut costume, bring to Burning Man, or wear to the next dance party! **This Instructable is V2 of the original that was published in 2015. ** (Check out V1 here: https://www.instructables.com/id/LED-Space-Helmet/) Updates include: New CAD files for the pivots, which can be downloaded direct from the Instructable! New pivot hardware parts list New collar design which has shoulder contours and an integrated holder for the LED controller, and can be downloaded from the Instructable Simplified LED installation This space helmet has a visor that opens and closes all the way so you can talk to other people or say brb, going into space. LEDs are arranged around the inside back of the helmet so it glows from the inside. The visor pivots (which hold the visor to the helmet) are a set that I custom-designed and can be printed on most any 3D printer."_ [...]
"Create a complete cloud-based weather sensor with humidity, pressure, temperature and light sensing. Out of the box, the AVR-IoT WG and PIC-IoT WG development boards already enable you to view temperature and light data from the cloud. Plug a MikroElektronika Weather Click into the MikroBUS socket to easily complete your weather sensor with humidity and pressure sensing. By the end of the tutorial, you will have a complete cloud-connected weather sensor and you will be able to view temperature, light, humidity, and pressure data from the Microchip Sandbox within the Google Cloud Platform IoT Core. " [...]
"The brachistochrone curve is a classic physics problem, that derives the fastest path between two points A and B which are at different elevations. Although this problem might seem simple it offers a counter-intuitive result and thus is fascinating to watch. In this instructables one will learn about the theoretical problem, develop the solution and finally build a model that demonstrates the properties of this amazing principle of physics. This project is designed for high school students to make as they are covering related concepts in theory classes. This hands-on project not only strengthens their grasp on the topic but also offers a synthesis of several other fields to develop. For example while building the model, students are going to learn about optics through Snell's law, computer programming, 3d modelling, digital frabrication and basic woodworking skills." [...]
"In this tutorial you are going to learn how to build your own light switch and fan dimmer in just one board with the microcontroller and WiFi module ESP8266. This is a great project for IoT. Cautions: This circuit handles AC main voltages, so be careful. Extra: I posted here a video tutorial that shows you the whole process. " [...]
"Hello to all, After browsing for many hours, and designing lots of cool stuff, I finally got around to actually building something. Therefore, get ready for my first Instructable! I spend a lot of my hours, both professionally as for fun, doodling around in AutoCAD. For ergonomic purposes I already bought an extra Numpad keyboard to use with my left hand, so I dont need to let go of the mouse. However, I still need to move my hand to type in certain commands like BOX or RECT. And to make things worse: I also need to hit the ENTER key after I do so." [...]
"Concept A drum machine which generates rhythms using probability. Imagine a traditional step-based drum machine, but where various dice are rolled for each step, with the resulting numbers used to determine the behaviour of the beat. Setup DrumKid is based around an Arduino, and coded using the Arduino IDE. Audio is produced by the Mozzi library. You can build a version of DrumKid using an Arduino, a breadboard, and standard electronic components, or you can build/buy the "full" version described below. Design DrumKid is a portable, handheld, battery-powered instrument with a minimalist design." [...]
"Once I was given the task to look for an environmental probe for monitoring the temperature in the server room of my company. My first idea was: why not just use a Raspberry PI and a DHT sensor, it can be setup in less than an hour including the OS installation. For this I got the cold response from blindfolded bossy people that we will not do that because it would cost more in work hours to set it up than buying a device. Having to accept narrow minded people like this for a part of my life was one thing and I ordered some enterprise grade EATON junk off Ebay and call it but I decided at that moment that for my own server room I will build a completely Open Source Arduino based device which will be much better than what I just ordered. This project is code named SilverLight, don't ask me where I get these names from :) I just looked at the shiny half acrylic box and decided with this name, it has nothing to do with the microhoof product what I found out about after. " [...]
"Hello guys Today I am presenting you my second project on instructables.This project presents the mixture of my first project in which I used Soil Moisture sensor and DHT22 sensor which is used for measuring temperature and humidity. This project is easy to make, and people that are using Arduino will feel it quiet interesting to make. Difference between this project and the first one is that in this project user will have menu in which he can chose what he wants to see at the moment. There will be four options. So grab you kit and start to make this project which can be used in any home. " [...]
"From the beginning ob building the FPV-Rover, I wanted to have a Nerf Dart Launcher on it. And finally, here it is. This is the fifth upgrade for the rover and it won't be the last. Videos: Links to the Rover Instructables: https://www.instructables.com/id/FPV-Rover-V20/ Thingiverse: https://www.thingiverse.com/thing:2952852 Links to the Trike Instructables: https://www.instructables.com/id/RC-Trike-With-Re... Thingiverse: https://www.thingiverse.com/thing:3669829 Supplies:nothing so far" [...]
"Today I am going to make a circuit of 3.7V Battery low and full charge indicator. Let's get started," [...]
"In this project we will have a short look at commercial function/waveform generators in order to determine what features are important for a DIY version. Afterwards I will then show you how to create a simple function generator, the analog and digital way. At the end I will then present you a DIY DDS function generator design which can (kind of) hold up to the commercial versions. Let's get started! " [...]
"Detect vehicles using QMC5883L and actuate swinging gate using relay to allow exit My folks have a swinging gate at the entrance of their driveway with a keypad on the outside. Guests can come easily, but due to an auto close but it is an unfortunately manual process to let them exit either by push button on the inside of the gate controller box itself or a garage remote with frustratingly limited range. They were interested in a vehicle detection induction loop but after finding consumer offerings for no less than $150+ USD, I knew I could do it for cheaper and have it be smarter. I originally considered an ultrasonic sensor to detect vehicle presence but decided not to in order to have have a cleaner and hopefully more accurate detection. After some basic research I came up mostly empty handed but stumbled on a forum suggesting the use of a QMC5883L magnetometer. $7 and a manual build of ESPHome later I had a working prototype!!" [...]
"In this video, we will create a link drop sensor with an ESP32 and a SIM800. This means that with this project, we can verify the connection to the internet, and in the event of a connection failure, call a telephone number to notify that the network is in trouble. This is one many ways you can perform this type of monitoring. While it's simple, it allows you to test various devices that may exist within your CPD. Its power of check becomes much greater when using the ESP32. Though I use WiFi in this example, you can use wired internet, if you prefer." [...]
"THE PREMISE: As a society, we need an open source device for reading. Books are among the most important documents of our culture, yet the most popular and widespread devices we have for reading — the Kobo, the Nook, the Kindle and even the iPad — are closed devices, operating as small moving parts in a set of giant closed platforms whose owners' interests are not always aligned with readers'. The Open Book aims to be a simple device that anyone with a soldering iron can build for themselves. The Open Book should be comprehensible: the reader should be able to look at it and understand, at least in broad strokes, how it works. It should be extensible, so that a reader with different needs can write code and add accessories that make the book work for them. It should be global, supporting readers of books in all the languages of the world." [...]
"Ever asked how to control any device from any place in the world? In this tutorial, we'll learn how to control things wirelessly over WiFi. Introduction Today, we will build a device that connects to the internet and allow the user to control his/her home remotely over wifi. we will use the Arduino board(any model will do the job well) with the ESP8266-01 wifi module to make this device. Let’s get started! What’s a smart home?" [...]
"Introduction The SparkFun Pulse Oximeter and Heart Rate Monitor is an I²C based biometric sensor. Utilizing two chips from Maxim Integrated, the SparkFun Pulse Oximeter and Heart Rate Monitor has both the MAX30101 biometric sensor and MAX32664 biometric hub. While the former does all the sensing, the latter is an incredibly small and fast Cortex M4 processor that handles all of the algorithmic calculations, digital filtering, pressure/position compensation, advanced R-wave detection and automatic gain control. We've combined them and written an Arduino Library with example code demonstrating basic to advanced features to help get you started utilizing the SparkFun Pulse Oximeter and Heart Rate Monitor into your next project. Or if you're looking to put these IC's into a final product, Maxim has provided some features to get FDA approval. Let's get started!" [...]
That's all Folks!