Nine reasons why the Barber Vintage Festival is the one motorcycle event you cannot say 'no' to

 

There's something for everyone at the Barber Vintage Festival (Credit: Somer Hooker / Gizmag) Image Gallery (160 images) Every October there’s a three day party in Birmingham, Alabama, for motorcyclists of all persuasions. Unlike most brand-specific get togethers, this event honors one and all, from the beginnings of motorcycling history to the wonderous two-wheeled technology of today. The event is kid-friendly, exceptionally well organized, incredibly welcoming and spotlessly clean.   It’s called the Barber Vintage Festival and it’s unlike any other event in the world. Here are the nine reasons why the Barber Vintage Festival is the one motorcycle happening you cannot say no to. Britten the featured marque in 2015 Every year Barber Vintage Festival picks a theme to expand upon, and as this year is the 20th anniversary of the passing of legendary New Zealand motorcycle designer John Britten, it presented the perfect opportunity to host a tribute to his work. Nine of the 10 existing Britten motorcycles were on hand, including the famed "Streamliner," as was the Britten family. To a Britten enthusiast, getting eyes-on just once in a lifetime might have to do, so to see them running in a pack on the track, racing in AHRMA and all displayed together in the Barber Museum was such a rare sight – even John Britten himself never got to see it. The tale of John Britten is a fairytale equally enchanting as that of fellow-Kiwi Burt Monro, who gained international acclaim for his home-grown innovation thanks to the movie The World's Fastest Indian. Britten was another motorcycle innovator from New Zealand, who put a whole new spin on "homebuilt" motorcycles. Built from the ground up, each of his V-twin motorcycles was a spectacular vision of "outside-the-box" thinking and captured the imagination of the world. In the early 90’s he brought an example to Daytona and was allowed to run it in Battle of the Twins where he made quite the display as his rider rode the rear wheel, flashing the peace sign to spectators as the competition tried to catch them. Sadly, John succumbed to cancer at age 45, robbing us all of what might have been. Brittens were sold with a tuning laptop in each crate which was remarkably innovative for the time. Expensive even then, (prices varied, but around US$75,000 seems to be the range), they are now among the most treasured motorcycles in the world and easily worth more than 10 times that now. With only 10 Brittens on the planet, George Barber saw to it that nine of them made it to the Vintage Festival. Think about that for a moment – that's 90 percent of the entire production run in one spot, turning the Barber Festival into an defacto Britten festival. Indeed, one of them was already there, because George Barber invested in John Britten’s dream early on and was one of the first buyers. He is to this day an original owner of the first Britten group. Those who attended the annual Motorcycles by Moonlight museum charity dinner got to see them all in one room. This proved to be much more intoxicating then any of the beverages served, at least until the next day when five were paraded on the track at once, with a couple on the back wheel in true Britten fashion. Kirsteen Britten, John’s wife, was on hand to speak about John’s life and passion. She also flagged off the parade lap with the bikes on the track Five Brittens on the track at once: never before and probably never again Kirsteen Britten leads the parade of Brittens while seated on the back of George Barber’s Porsche Spyder   George Barber and his staff The Southern gentleman turned around on the tram. "Is everything all right? Is there anything you need?" He had white hair and look of concern as we rode around the track. None other than Mr. George Barber himself was sampling the service being provided at the grounds that bear his name. He patiently moves through the crowds like a host at a Derby Day party, making sure everyone is content and everything is sufficient. One of the hallmarks of the Barber Vintage Festival is plain old Southern Hospitality. Some meets have organizers and staff that interact with their patrons more like taskmasters with whips. Not so at Barber’s. All staff will treat you with courtesy and genuine concern. They want to make sure you’re happy and help if you’re not. It’s important to ask and listen, to learn to improve. It’s a mandate that comes directly from the top, Mr. Barber himself. And it’s the secret sauce to how they always manage to take it up several notches every year. The gentleman who makes it all possible, George Barber The Museum and Grounds It’s the first thing you see when you enter the park and frankly, it’s just plain majestic. Five stories of poured concrete with a glass front that brings to mind more upscale hotel than motorcycle museum. Barbers is often described as an 850 acre botanical garden with a race track and what is commonly regarded as the best motorcycle museum in the world. The grounds are spotless, and the crowds at BVF respect that. There is a huge camp area and it’s popular, with good bathrooms and lovely views. The ground staff knows what’s nesting here, what has babies, and concern for the surrounding environmentally sensitive river is paramount. The race track is sold out most of the year for track days and corporate functions, Porsche and Mercedes have offices on the grounds. So while it’s probably true that the grounds and racetrack each sets a world standard, it’s the museum that stands alone in it’s unlikely to ever be contested "Best In The World" status. The state of the art dedicated building holds roughly 1600 motorcycles and is currently undergoing an expansion that will double its size. Inside the vast collection is the largest Lotus car collection in the world as well as many machines a staunch enthusiast will recognize as the core MOMA Art of the Motorcycle exhibit. You could easily spend a day in the museum alone and many do just that.   The Racing Sparse grids, single file races? Not at Barbers. This is the race entrants look forward to all year, so much so that AHRMA, the series that sanctions the weekend had to find a way to limit entry’s by requiring pre-Barber qualifier races in order to get in. The resulting full grids, top name racers and busy paddock make for outstanding spectating. The best part? It’s all included in the price of your standard BVF gate admission. If you get tired of watching the road races (which includes the Century race and of course the Britten on track exhibition), there’s vintage MX dirt track racing thru the surrounding woods as well.   The Motorcycle Swap meet The swap meet has six hundred vendor spaces and sells out months before the event. and the Barber staff works hard to keep the focus on small vendors. Jeff Ray CEO noted years ago that when one mega meet kept increasing its fees due to popularity, the smaller guys got nudged out. Soon it was nothing but professionals selling reproduction parts and services. He realized that attendees have a "lust for rust," that they like to find those small treasures like the Pickers do. In fact the swap meet has a pickers contest. The entrants with the most unusual item entered, are awarded a trophy and a free space the next year. Vendors have been known to make sales just as they pull in   The Century Race Early on the Museum began "The Race of the Century." To enter, participants had to have a motorcycle at least 100 years old. Each year the field got larger and the speeds faster. By 2012 (1912) better brakes and dual speed rear ends were making it really interesting. Last year they realized that they were now getting into the era of 3 speed transmissions and big V-twins. Speeds would be approaching 80+ mph. The focus shifted to a parade lap for 100+ year old motorcycles. The happy result is the Indian – Harley wars might never end. At least not while Barber is offering such a choice battlefield. The year the field consisted of a couple of Harley Davidsons that had been battle tested in a Cannonball cross country run, a Triumph single and an Indian V-twin. Another facet of the mid-day activities on Saturday is a parade lap of honor for any machine that had participated in the Cannonball race, a cross country rally for pre-1936 or pre 1916 motorcycles depending on the year. It’s quite a show – the gambit ran from flat tank Harley Davidsons to Art Deco BMWs. Crossing the finish line always feels good – 1929 101 Indian Scout Motorcycles On Parade We’ve all heard the term "Three Ring Circus," where three separate shows were going on at once under the Big Top. Multiply that times three at The Barber Vintage Festival. Early on the VJMC (Vintage Japanese Motorcycle Club) and AMCA (Antique Motorcycle Club of America) became one of the foundations for the festival. Each club was given an area to stage a ride-in bike show. It was popular and as the festival grew, more shows sprung up; formally and informally. Motorcycle Classics magazine took over the formal task of the "main" bike show and with the promise of the winner making the magazine owners started turning up with bikes from all 49 states. Soon Ace Café joined the party with one of their own as well – for an additional fee you could enter its build-off show and sip adult beverages while watching the races (by paying admission to a private area).   The Art One of the most unexpected things about Barbers is the applications of art in its public spaces. They vary from whimsical (like the giant ants carrying away a motorcycle and rider as well as a giant Coca Cola bottle), the ultra-serious (The Ted Gall sculpture "The Chase" on the museum’s front lawn) and the iconic (the giant spider in the race track front straight grass by the Charlotte’s Web turn). A walk around the track might take you past a pride of lions on the hunt, an Indian totem, giant flowers with spinning petals, Don Quixote on his horse, and a man seemingly drowning in a lake known as the "Zombie Frenchman." Art is all throughout the museum too and it’s not just interesting, it’s remarkably clever – a real car in parts displayed to resemble a giant model car kit, and "trees" made of motorcycles that seem to grow thru the museums floors are but two examples of many. It’s not a stretch to suggest a visit here for the art and artistic displays alone.   Thrill Shows One of the favorite past times at any motorcycle event is the Motorcycle Thrill Show and like everything else at Barber’s they deliver three times more entertainment than you might expect. The traditional stunt show is taken over the top (literally) by the On The Edge motorcycle stunt show. Based in the UK this accomplished quartet of trials bike experts pull off the impossible numerous times a day. Nestled in the fan zone is a strange looking metal mesh ball that houses as many as three genuine "daredevil" riders at a time all somehow managing to miss each other as they ride inside the sphere fast enough to glue themselves with centrifugal force upside down at speeds up to 60 mph. The three "man" team is actually two guys and a gal and the crowd loves that reveal, which is saved until the end. More surprising is that this, like many carnival shows, is a family business and the globe (and show) date back to 1912 when the Uris family took it on the road. Completing the trio is an old fashioned Wall of Death. This mother of all carnival shows is run by the American Motor Drone Company and showcases the vintage American sport of board track racing using antique Indian and Harley Davidson motorcycles. Fans stand inches from the riders who scream by and grab dollar bills from the crowd as the whole platform sways with the force of the machines inside it. If you have never seen it this authentic (and memorable) piece of Americana it’s like stepping thru a doorway back in time.   Want to attend the Barber Vintage Festival in 2016? Plan ahead. Camping and swap meet spots sell out in days once sales open. This year’s crowd of 69,000 attendees was a record but there were almost no lines to get in or anywhere else, and buying your $60 (or less with advance purchase) three day pass is part of that lovely no-waiting-in-line process. The website is really informative, check out this link for the FAQ. In the meantime, take a closer look at all of these reasons (and more) to put this ebent on your agenda in our extensive Barber Festival photo gallery.   http://www.gizmag.com/barber-vintage-festival-motorcycle-show/40056

Northrop Grumman chosen to build next US strategic bomber

 

 

The design and specifications of the Northrop Grumman bomber are still highly classified, as is implied in this still from a recent Northrop advert (Credit: Northrop Grumman)

The US Air Force has awarded a US$21.4 billion contract for its Long Range Strike Bomber (LRS-B) to Northrop Grumman. The next generation of strategic bombers will replace the aging fleets of B-52s and B-2s, and will be capable of carrying heavy or nuclear payloads against new generations of anti-aircraft systems.

The contract is a bit of a surprise, since Northrop Grumman is only a sixth of the size of Lockheed Martin and Boeing, who were partners in a rival bid. However, Northrop has strong experience in stealth technology and bomber construction, which seems to have offset the partnership's advantages of size.

Operating on a budget based on the Northrop's bid and an independent assessment to prevent underbidding, the two-part contract covers development and production spread over two decades. The first part is the US$21.4 billion for Engineering and Manufacturing Development (EMD) to cover development costs with incentives against overruns. The balance covers 80 to 100 LRS-B aircraft to be built in five tranches of 21 aircraft with production extending into the 2040s. Cost per aircraft is estimated at US$511 million each, depending on the number purchased.

The next generation bomber may be based in part on the B-2 Spirit bomber

The LRS-B is expected to enter service by the mid 2020s and though its specifics are still highly classified, it's likely to be based on the still-secret RQ-180 unmanned surveillance aircraft and the B-2 Spirit bomber currently in service. Based on the program requirements, it will be capable of carrying out missions involving strategic bombing, tactical bombing, and global strike, surveillance, reconnaissance, intelligence, and electronic attack. It will also carry nuclear weapons, but, due to arms control treaties, not until older nuclear bombers start retiring.

One goal of the LRS-B is to avoid the massive cost overruns of previous defense aircraft programs by relying on existing technology where possible to prevent spiralling development costs, which left the B-1 and B-2 programs as rumps of their intended deployments. The LRS-B will probably be lighter and smaller than the B-2, though with better aerodynamics and efficiency. The latter is particularly important because the high-tech B-2 is only as efficient as a B-52.

According to Air Force acquisition chief William LaPlante in an interview withAviation Weekly, the LRS-B will use lessons learned from previous warplane projects and includes technologies that are already under development and even operational, though their exact nature is classified. The bomber will use more advanced materials and greater stealth. It will also use open architecture to allow for upgrades without major alterations and testing, which will help to keep down development and maintenance costs.

"The LRS-B will provide our nation tremendous flexibility as a dual-capable bomber and the strategic agility to respond and adapt faster than our potential adversaries," says Geneal Mark A. Welsh III, Chief of Staff of the Air Force. "We have committed to the American people to provide security in the skies, balanced by our responsibility to affordably use taxpayer dollars in doing so. This program delivers both while ensuring we are poised to face emerging threats in an uncertain future."

Sources: Northrop Grumman, US Air Force

Turbinas eólicas

 

Universidade Federal do Rio de Janeiro Escola de Engenharia Depto. de Eletrotécnica Energia Solar Fotovoltáica Prof. Stefan Krauter Fontes de Energia Renováveis Geração Eólica Marcele Medeiros Monteiro de Barros Verônica Souza de Queiroz Varella Turbinas Eólicas A turbina eólica, ou aerogerador, é uma máquina eólica que absorve parte da potência cinética do vento através de um rotor aerodinâmico, convertendo em potência mecânica de eixo (torque x rotação), a qual é convertida em potência elétrica (tensão x corrente) através de um gerador elétrico. A turbina eólica é composta pelo rotor e pela torre que o sustenta, pela transmissão/multiplicação e pelo conversor. Ela pode extrair energia cinética somente do ar que passa através da área interceptada pelas pás rotativas. Embora combinada com a eficiência do modelo, a área varrida pelo rotor circular (p r2) é um fator crucial na determinação da energia entregue pela turbina eólica. A energia cinética bruta por unidade de tempo, potência, do vento passando por uma área A perpendicular ao seu vetor velocidade instantânea V, é dada por: P = Cp 1/2 r .A.V3 onde : r = densidade do ar, que varia com a latitude e as condições atmosféricas; r @ 1.2kg/m3; Cp= é o coeficiente da performance que se relaciona com a energia cinética de saída e depende do modelo e na relação entre a velocidade do rotor e a velocidade do vento. V = velocidade do vento em m/s2. A energia potencial da turbina eólica depende do cubo da velocidade do vento; isto significa, por exemplo, que se a velocidade do vento em um local dobrar, a energia potencial de saída de uma turbina eólica é multiplicada por 8 ( 23 ). Esta sensibilidade da energia com a velocidade do vento mostra a importância na obtenção dos dados do vento para a estimativa da energia disponível. A velocidade média anual é um bom parâmetro para pesquisar o vento. A tabela 2.12 serve como guia. Além da velocidade média anual do vento, as médias mensais são úteis, já que elas dão uma melhor idéia das variações seasonais. Isto é importante quando a investigação do abastecimento de energia irá partir da demanda mensal. A velocidade do vento decresce à medida que se aproxima da superfície da terra devido à fricção entre o ar e a solo. A quantidade de decréscimo depende da rugosidade do solo; por exemplo, áreas florestais têm menor escoamento de ar que áreas descampadas. Medições em estações meteorológicas são geralmente tomadas em duas alturas-padrão: 2 metros ( para propósitos agrícolas ) e 10 metros ( o padrão internacional para medições meteorológicas ). Pode ser possível obter dados de um instituto meteorológico que tenha as velocidades médias anuais do vento de todas as estações metereológicas do país. Também pode ser válido tentar obter dados de uma universidade local. Se houver uma estação meteorológica perto do local proposto, obtenha seus dados lá. Se possível, visite a estação para checar se ela não está rodeada por construções ( por exemplo, árvores) que possam levar a medidas não confiáveis. Se houver dúvidas sobre a validade das medições, use os dados coletados nos aeroportos, que são geralmente os mais confiáveis. Mesmo quando o local está a 100 Km da estação meteorológica, os dados podem ainda ser usados em conjunto com as comparações entre a estação e o local. Entretanto, diferentes circunstâncias podem necessitar de correção de dados meteorológicos. Por exemplo, locais perto das costa geralmente têm velocidades do vento maiores do que as de uma ilha; a velocidade do vento numa ilha é cerca de 2/3 daquela próxima à costa. Também é necessário comparar o terreno. Estações meteorológicas geralmente fornecem velocidade do vento em terreno-aberto. Quaisquer obstáculos tais como moitas, árvores e construções reduzem significativamente a velocidade do vento e montanhas podem gerar ventos muito turbulentos concentrados num local. Também é importante a coleta de dados em tornados e calmarias. Turbinas eólicas são normalmente projetadas para resitir a velocidades de vento abaixo de 55 m/s; assim é necessário conhecer a velocidade de sobrevivência da turbina. Calmarias não ameaçam a turbina, mas podem levar a períodos inaceitáveis sem saída de energia. Velocidade média anual 10 m acima do nível do solo Possibilidades de uso para a energia eólica Abaixo de 3 m/s Usualmente não viável, a menos em ocasiões especiais 3-4 m/s Pode ser uma opção para bombas eólicas, improvável para geradores eólicos 4-5 m/s Bombas eólicas podem ser competivas com bombas à Diesel. Pode ser viável para geradores eólicos isolados Mais que 5 m/s Viável tanto para bombas eólicas quanto para geradores eólicos isolados. Mais que 7 m/s Viável para bombas eólicas, geradores eólicos isolados e conectados à rede. 1 Rotor Componente destinado a captar energia cinética dos ventos e convertê-la em energia mecânica no eixo. Se o eixo do rotor for posicionado horizontal ou verticalmente, teremos um rotor de eixo horizontal ( rotor hélice, rotor multipás ( multivane fans ), rotor holandês, etc. ) ou um rotor de eixo vertical ( rotor Savonius, rotor Darrieus, etc ). Rotor de eixo horizontal Rotores de eixo horizontal são movidos por forças aerodinâmicas chamadas de forças de "lift" e forças de "drag". Um corpo que obstrui o movimento do vento, sofre a ação de forças perpendiculares ao fluxo de vento relativo ( forças de "lift" ) e de forças paralelas ao fluxo de vento relativo ( forças de "drag", de arraste). Ambas as duas são proporcionais ao quadrado da velocidade relativa do vento. Adicionalmente, forças de "lift" dependem fortemente da geometria do corpo e do ângulo entre a velocidade relativa do vento e o eixo do corpo, dito "ângulo de ataque". Rotores que giram predominantemente sob forças de "lift" permitem liberar muito mais potência do que aqueles que giram sob o efeito de forças de "drag", para uma mesma velocidade do vento. Os sistemas com eixo horizontal, perpendicular ao fluxo do vento, por um lado são movidos predominantemente por forças de "lift" e devem ser montados sobre uma gávea giratória provida de movimento em torno de um eixo vertical ( "yaw" ) para que o disco varrido pela pás esteja sempre em posição perpendicular ao vento. Quanto à sua posição relativa à torre, o disco varrido pelas pás pode estar a juzante do vento ( "down wind rotors") ou a montante do vento ( "up wind rotors" ). Uma razão para localizar o rotor a juzante da vento é que esse arranjo facilita a conicidade do rotor. O ângulo de conicidade é vantajoso por aliviar as tensões na raiz da pá, equilibrando parcialmente os momentos devidos às forças centrífugas. A desvantagem de localizar o rotor a juzante do vento é que as pás sofrem carregamento cíclico ( causadores de fadiga ) quando elas passam pela "sombra aerodinâmica",.apesar desse efeito poder ser minimizado com o emprego de torres mais esbeltas, ou afastando as pás da torre com ângulo de conicidade. A localização do rotor a montante da torre reduz o efeito de interferência cíclica da esteira ( "sombra") da torre nas pás para um nível mínimo de altitude. Entretanto, o rotor assim deve ser sem articulações e posicionado bem adiante da torre, mesmo sob condições extremas de velocidade de vento. Não existe nenhuma evidência nítida quanto a qual localização do rotor - quer a montante, quer a juzante - seja a mais vantajosa, pelo menos no que se concerne aos aspectos de custo total de máquinas eólicas. Na dimensão dos aerogeradores das "wind farms" americanas, a maioria dos aerogeradores lá usados são a montante do vento. Rotor de eixo vertical Em geral, rotores de eixo vertical têm a vantagem de não precisarem de mecanismos de acompanhamento para variações de direção do vento. Isto reduz a complexidade do projeto e os esforços devido a forças de "Coriolis". Também os rotores de eixo vertical podem ser movidos por forças de "drag" ou por forças de "lift". Os principais tipos de rotores de eixo vertical são: - Savonius - Darrieus - Turbina com torre de vórtices Os rotores do tipo Savonius são movidos predominantemente por forças de "drag" embora desenvolvam algum "lift". Têm relativamente alto torque de partida, embora em baixa velocidade. Sua eficiência é baixa. Seu rendimento mecânico máximo pode atingir 31%. Os rotores tipo Darrieus desenvolvidos em 1927 pelo francês G.J.M Darrieus são os mais fortes concorrentes aos cataventos convencionais de hélices. São movidos por forças de "lift". Constituem-se de lâminas ( duas ou três ) curvas de perfil aerodinâmico atadas pelas duas pontas ao eixo vertical. Em rotação, suas lâminas são curvadas por força centrífuga até um diâmetro aproximadamente igual a distância entre as pontas, assumindo a forma de uma catenária. Podem atingir alta velocidade, mas o torque de partida é aproximadamente nulo. Várias configurações podem ser concebidas. Estes rotores podem ser combinados a outros rotores para aumentar o torque de partida. Sua eficiência é alta, quase comparável aos tipos convencionais de cataventos. As turbinas com torre de vórtice são unidades mais compactas do que outros cataventos, fixada uma potência de saída. Estão em estágio de desenvolvimento. Construtivamente, as pás podem ter as mais variadas formas e empregar os mais variados materiais. Em particular, pás rígidas de madeira, alumínio, aço, fibra de vidro, fibra de carbono e/ou Kevlar são os mais promissores. Fibras de vidro: Materiais compostos reforçados com fibra de vidro oferecem boa resistência específica e resistência à fadiga, bem como os custos competitivos para as pás. É o material utilizado em quase todas as pás dos aerogeradores dos parques eólicos da Califórnia ( EUA ), e já foi utilizado em rotores de até 78m de diâmetro. As pás em materiais compostos possibilitam uma geometria aerodinâmica lisa, contínua e precisa. As fibras são colocadas estruturalmente nas principais direções de propagação das tensões quando em operação. Aço: Os aços estruturais são disponíveis a custo relativamente baixo no mercado interno de alguns países, e há bastante experiência na sua utilização em estruturas aeronáuticas de todos os tamanhos. No entanto, uma desvantagem do aço é que as pás nesse material tendem a ser pesadas, o que acarreta aumentos de peso e custo de toda a estrutura suporte. Pás de aço necessitam de proteção contra a corrosão, para a qual existem diversas alternativas possíveis. Madeira: Essa fibra natural, que também constitui um material composto, evoluiu ao longo de milhões de anos para suportar cargas de fadiga induzidas pelo vento, que tem muito em comum com aquelas a que são submetidos os rotores de aerogeradores. A madeira é amplamente utilizada no mundo para pás de rotores pequenos ( até 10 m de diâmetro ). O baixo peso da madeira é uma vantagem, mas deve-se cuidar para evitar variações do teor de umidade interna, o que pode causar degradação das propriedades mecânicas e variações dimensionais, que enfraquecem a estrutura das pás e podem causar rompimentos na estrutura. Alumínio: a maior parte dos aerogeradores do tipo Darrieus usam pás feitas de ligas de alumínio, extrudadas na forma de perfil aerodinâmico. Entretanto, ligas de alumínio não têm limite inferior de tensão de fadiga, à medida que os ciclos de carregamento são aumentados, e este comportamento sempre tem levantado dúvidas quanto à possibilidade de se atingir a longa vida de 20 anos ou mais para um rotor de alumínio. Fibra de carbono e/ou Kevlar: são materiais compostos mais avançados, que podem ser utilizados em áreas críticas ( longarina da pá, por exemplo ), para melhorar a rigidez da estrutura. Tem sido utilizados experimentalmente, mas tais materiais tem preços altos demais para serem utilizados nos aerogeradores economicamente mais competitivos. A maioria dos rotores modernos tem duas ou três pás. Os projetistas americanos tem escolhido geralmente duas pás com base no argumento de que o custo de duas pás é menor que o de três. Outros, especialmente os dinamarqueses, argumentam que o custo extra da terceira pá é compensado pelo comportamento dinâmico mais suave do rotor de três pás, e que o custo total do aerogerador é virtualmente idêntico quer se usem duas ou três pás. Um rotor de três pás fornece oscilações menores de torque no eixo, o que simplifica a transmissão mecânica. Se um rotor de duas pás é escolhido - pelo menos para aerogeradores grandes - é usual se ter o rotor articulado, isto é, permitindo uns poucos graus de movimento perpendicular ao eixo de rotação. Com um cubo articulado, cada pá, ao passar pelo topo do círculo de rotação - onde a velocidade do vento é maior devido ao gradiente vertical - move-se um pouco para trás; ao mesmo tempo a outra pá, no curso inferior do círculo de rotação - onde o vento é menor - move-se para frente. Este movimento de articulação alivia significativamente as tensões na raiz das pás, e o consequente custo/benefício mais do que compensa pelo custo extra da articulação no cubo. Como o peso próprio das pás introduz cargas cíclicas na raiz (no plano de rotação ), e também penaliza a estrutura da torre, as pás devem obedecer ao critério de peso mínimo, resistência à fadiga e rigidez estrutural. Rotores modernos com mais de três pás são apenas usados quando se necessita de um grande torque de partida, o que é basicamente o caso de bombeamento mecânico de água. Aerodinamicamente, no entanto, grande número de pás e alto torque de partida implicam em menor eficiência. O rotor deve ser fabricado com grande esbeltez, precisão nos perfis aerodinâmicos, bom acabamento superficial, que são requisitos para maximizar a eficiência aerodinâmica. Sistemas de controle para limitação de potência A potência contida no vento é proporcional ao cubo da velocidade do vento, mas velocidades muito altas de vento ocorrem com uma frequência relativa muito pequena. Estes ventos pouco frequentes contribuem muito pouco para a energia gerada, e não seria economicamente esperto projetar aerogeradores para operar eficientemente sob tais condições; os elevados carregamentos nas pás e as grandes potências de pico acrescentariam custos extras substanciais ao custo do aerogerador, e dariam um incremento de energia gerada muito pequeno. Estes custos extras podem ser evitados se for limitada a potência do aerogerador para ventos fortes. Isto é mais frequentemente conseguido arranjando-se para que toda extensão da pá (ou apenas parte dela ) seja rodada em torno de seu eixo longitudinal, de forma a aumentar o ângulo de passo da hélice, o que reduz as cargas e a eficiência aerodinâmica durante o período de ventos fortes. A variação de passo limita a rotação e as cargas aerodinâmicas. O enfoque alternativo é usar pás de passo fixo, que tornam o cubo mais barato e simples de fabricar, em conjunto com gerador de rotação constante, e deixar que a pá estole e limite a potência, quando sob ventos fortes. A rotação constante pode ser facilmente obtida para geradores conectados à rede, pelo emprego de gerador síncrono ou de indução. Então à medida que a velocidade do vento aumenta, o ângulo de ataque em que o escoamento encontra a pá aumenta, até que o escoamento sobre o rotor descola e a potência gerada se reduz. 2- Transmissão/ Multiplicação A velocidade angular de rotores varia habitualmente na faixa de 15 a 220 rpm devido a restrições de velocidade na ponta da pá (tangenciais), que operam na ordem de 50 a 110m/s, quase independentemente do tamanho do diâmetro. Como geradores trabalham, sobretudo geradores síncronos, a rotações bastante mais altas ( comum entre 1200 e 1800 rpm), torna-se necessária a instalação de sistemas de multiplicação entre o eixo do rotor e o eixo do gerador. Isto significa geralmente um multiplicador convencial, com dois ou três estágios de engrenagens, apesar de transmissões metálicas também terem sidos experimentadas. Nos aerogeradores conectados às redes de distribuição elétrica, a rotação no gerador é de, tipicamente, 1500 rpm ( para 50 Hz) e de 1800 rpm ( para 60Hz ). Para aplicações onde a rede é de alta potência, o simples e confiável gerador de indução ( assíncrono ) pode ser usado; a rotação é então mantida dentro de uma certa percentagem da rotação síncrona ( um pequeno ângulo de "escorregamento" é essencial para a operação deste tipo de gerador). Devido a esta pequena ( mas finita) margem de velocidades é permitida alguma absorção de energia das flutuações rápidas de vento na forma de energia cinética do rotor pela sua inércia. Desta forma, as flutuações de cargas nas engrenagens da caixa de multiplicação são levemente suavizadas. Para alguns rotores de tamanhos pequenos, é possível a conexão direta, pois por exemplo, rotores de 1m de diâmetro podem atingir rotações de até 2000 rpm. Também, para potências na ordem de poucos quilowatts, geradores especiais podem ser construídos, com baixa rotação, para conexão direta aos rotores. Para potências acima de 1 a 2 kW, e rotores com mais de 3m de diâmetro, a regra geral é a utilização de alguma forma de multiplicador de velocidades entre o rotor e o gerador. Correias, correntes e transmissões hidráulicas têm sido utilizadas, mas a forma mais amplamente utilizada e provavelmente com maior sucesso é a transmissão por engrenagens, nas suas várias formas, desde engrenagens de dentes paralelos a dentes helicoidais, sistemas planetários ou não. A multiplicação por engrenagens é a de maior eficiência. Multiplicação por correias ou correntes tem a possibilidade de baixos custos, porém são viáveis apenas para pequenas potências 3- Geradores A transformação de energia mecânica de rotação em energia elétrica através de equipamentos de conversão eletromecânica é um problema tecnologicamente dominado. Grupos geradores são correntemente industrializados e comercialmente disponíveis. A problemática na integração dos grupos geradores existentes a sistemas de conversão eólica envolve: - variações na velocidade do vento ( extensa faixa de rotações por minuto para a geração ); - variações do torque de entrada ( posto que variações na velocidade do vento induzem variações de potência disponível no eixo conjunto gerador); - exigência de frequência e voltagem constante na energia final produzida; - facilidade de instalação, operação e manutenção de tais engenhos devido ao isolamento geográfico de muitos desses sistemas, sobretudo em caso de pequena escala de produção. ( isto é, alta confiabilidade dos equipamentos); - baixos custos. Para aplicações isoladas, onde geralmente o objetivo é carregar baterias, existem duas opções: gerador de corrente contínua ou gerador síncrono com retificador. Em geradores DC não há necessidade de controle da velocidade do rotor e a tensão é independente de velocidade constante, uma vez que se exerce um controle sobre o campo, entretanto geralmente são mais pesados, mais caros, a fabricação é principalmente para baixas potências, necessita de regulador de tensão acoplado ao campo e de manutenção periódica. No Brasil, para potências maiores que 1 kW, são usados os geradores síncronos com retificador. Geradores e alternadores automotivos são produzidos em grande quantidade, têm baixo custo ( por Watt ), e têm assistência técnica em praticamente todo o território nacional. No entanto, existem apenas para potências abaixo de 1 kW ( os mais comuns são de 200-500 Watts ), têm baixa eficiência e alta rotação, o que faz de seu uso um compromisso técnico-econômico difícil. Já para os aerogeradores conectados à rede, as principais opções que existem são: geradores síncronos, geradores assíncronos ( de indução ) e geradores de comutador de corrente alternada. O tipo de gerador decididamente influencia o comportamento em operação do aerogerador e suas interações com a rede. As tensões mecânicas e as flutuações rápidas de potência gerada diminuem quanto maior for a capacidade e a amplitude das variações de rotação permissíveis no gerador. Geradores Síncronos Grande parte dos sistemas de conversão de energia eólica construídos até hoje, de média e grande escala de produção, usam geradores síncronos para a conversão eletromecânica. O estado de desnvolvimento tecnológico de tais equipamentos os recomenda fortemente. Dois tipos de excitação de campo são permitidos: (1) excitatriz independente, por baterias, com carregamento e (2) excitatriz acoplada a rotação do eixo com campo de ímã permanente. Suas vantagens são: - Não há virtualmente limitação de potência para sua fabricação; - Podem ser ligados diretamente à rede; - Alta eficiência (h g = 0.98 ); - Permitem melhor controle do fator de potência da carga. E as desvantagens: - Se ligado à rede, é necessário manter velocidade de rotação constante no sistema, posto que a constância de sua frequência depende intrinsecamente da constância da velocidade de rotação. Caso contrário poderá apresentar problemas de instabilidade. - Necessita regulador de voltagem acoplado ao campo. Geradores Assíncronos Esses geradores não possuem campo de excitação. Comparativamente com geradores síncronos, entretanto, necessitam de maior torque de partida para "cut-in" (acoplamento). Para o gerador de indução, variações limitadas de rotação são possíveis, dentro da margem de "escorregamento" do gerador. Isto permite maior elasticidade em rotação do que o gerador síncrono, o que reduz tensões mecânicas e flutuações elevadas de potência gerada quando da ocorrência de rajadas de curta duração, permitindo alguma absorção da energia da rajada de vento na forma de energia cinética pela inércia do rotor, e são eliminados os problemas de instabilidades em transientes. Além disso, geradores de indução são mais robustos, requerem mínima manutenção e têm uma longa vida em operação. O gerador de indução também possibilita conexão direta `a rede sem a necessidade de sincronização ou de regulação de voltagem. Entretanto, alguns problemas podem ocorrer com a magnetização, a corrente de partida e com o controle de potência reativa, especialmente nas seções de alta impedância da rede elétrica onde tiver instalado. No caso dos parque eólicos da Califórnia, praticamente todos os aerogeradores em uso têm geradores de indução. Geradores de Comutador de Corrente Alternada São geradores adaptados especialmente para produção de frequência variável. Têm excitação independente por gerador de baixa potência, pulsando com a frequência desejada. Sua concepção é similar às excitatrizes de grandes turbo-geradores ( 1000 MW ) do tipo conhecido sob o nome de "brushless excitation system". A limitação tecnológica de potência situa-se na faixa de 5 MW. Vantagens: - A frequência de saída é sempre igual à frequência de excitação: independe da velocidade de rotação do eixo do gerador.; - Melhor controle do fator de potência da carga; - Podem ser usados eventualmente como gerador síncrono. Desvantagens: - Custo da ordem de 20% acima de geradores de corrente contínua; - Exigem manutenção periódica: troca de escovas, etc. A tecnologia eletrônica moderna de estado sólido para grandes potências, tornou comerciais retificadores e inversores de estado sólido capazes de operar em potências comuns de sistemas de conversão. Conjuntos de gerador síncrono - transformador - retificador - inversor de estado sólido e gerador são sistemas disponíveis e utilizáveis comercialmente, para o caso de sistemas de conversão de energia eólica de velocidade variável e frequência constante. Estão em investigação: Conversores cíclicos, Alternadores de frequência, Geradores de campo modulado, entre outros exemplos. Geradores de corrente contínua, não considerados anteriormente em faixas superiores de potência devido ao alto custo de alternadores associados para a geração de corrente alternada, começam a ser reconsiderados em média ou larga escala de produção pela facilidade de armazenamento elétrico em conjuntos de baterias e o desenvolvimento de Inversores. 4- Torre As torres que elevam os rotores a altura desejada, estão sujeitas à inúmeros esforços. Primeiramente forças horizontais devem ser levadas em conta: resistência do rotor ( "drag" ) e da própria torre à força do vento. Em seguida, forças torsionais, impostas pelo mecanismo de controle de rotação da gávea giratória e esforços verticais (peso do próprio equipamento), não devem ser desprezados. Quanto ao material, as torres podem ser de aço (em treliças ou tubulares), ou tubulares de concreto. Para aerogeradores menores, é possível a utilização de torres de madeira sobre um poste de eucalipto com estais de aço. A torre suporta a massa da nacele e das pás; as pás, em rotação, excitam cargas cíclicas no conjunto, com a frequência da rotação e seus múltiplos, e assim uma questão fundamental no projeto da torre é a sua frequência natural, que deve ser desacoplada das excitações para evitar o fenômeno de ressonância, o qual aumenta a amplitude das vibrações e tensões resultantes e reduz a vida em fadiga dos componentes, entre outros efeitos desagradáveis. Logo após 1973, a primeira geração de aerogeradores ditos modernos foi projetada com torres rígidas, com frequências naturais bem acima das forças de rotação do rotor. Entretanto, esse enfoque conduziu a torres desnecessariamente pesadas e caras. À medida que a compreensão dos problemas dinâmicos de aerogeradores foi aumentando, durante a última década, tornou-se possível aerogeradores mais leves, que são consequentemente menos rígidos, mas também significativamente mais baratos que seus antecessores. Desde que tenha as suas frequências naturais desacopladas das da excitação do rotor, as torres podem ser estaiadas ou não. De modo geral, as frequências naturais de uma torre estaiada podem ser melhor reguladas variando-se a tensão de estaiamento. Interessante notar que um estaiamento por barras de aço é preferível ao uso de cabos, pois estes são mais elásticos e necessitam de pré-tensões muito maiores do que as que seriam necessárias em barras para atingir a mesma frequência natural, numa mesma configuração. Um aerogerador moderno constitui uma estrutura esbelta, com a massa das pás em rotação sobre uma torre, excitando cargas cíclicas sobre todo o sistema. Um problema básico do projeto é determinar todos os modos e frequências naturais de vibração dos componentes, em especial pás e torre, para evitar ressonância com as frequências de excitação do rotor em operação. A ressonância causa aumento das amplitudes de carregamento cíclico no sistema, comprometendo a resistência à fadiga e reduzindo a vida útil prevista para o aerogerador, que é de aproximadamente 20 anos. Referência Bibliográfica sobre Energia Eólica [1] - CHESF - Fontes Energéticas Brasileiras - Energia Eólica Vol III - 1987 [2] - Relatório elaborado para a ELETROBRÁS por Scientia - Sistemas de Conversão de Energia Eólica - 1977. [3] - HIRATA, Miguel - Energia Eólica, Uma Introdução ; Laboratório de Mecânica dos Fluidos - COPPE ,UFRJ -1985. [4] - HULSCHER, Wim and FRANKEL, Peter - The Power Guide - University of Twente, 2a ed. - 1994 [5] - HUNTER & ELLIOT - Wind- Diesel Systems - Cambridge University Press, 1994.   http://www.solar.coppe.ufrj.br/eolica/eol_txt.htm

A better way to pack natural gas into fuel tanks

 

Tue, 10/27/2015 - 7:25am Robert Sanders, UC Berkeley Flexible MOFs undergo a dramatic structural change when they adsorb methane, rapidly going from a nonporous to a highly porous material. This animated gif shows one pore of the material. Image: Jarad Mason/UC BerkeleyA new and innovative way to store methane could speed the development of natural gas-powered cars that don’t require the high pressures or cold temperatures of today’s compressed or liquefied natural gas vehicles. Natural gas is cleaner-burning than gasoline, and today there are more than 150,000 compressed natural gas (CNG) vehicles on the road in the U.S., most of them trucks and buses. But until manufacturers can find a way to pack more methane into a tank at lower pressures and temperatures, allowing for a greater driving range and less hassle at the pump, passenger cars are unlikely to adopt natural gas as a fuel. UC Berkeley chemists have now developed a porous and flexible material—a so-called metal-organic framework (MOF)—for storing methane that addresses these problems. The flexible MOF collapses when the methane is extracted to run the engine, but expands when the methane is pumped in at only moderate pressure, within the range produced by a home compressor. “You could potentially fill up at home,” said Jeffrey Long, a UC Berkeley professor of chemistry who led the project. The flexible MOF can be loaded with methane, the main ingredient of natural gas, at 35 to 65 times atmospheric pressure (500 to 900 psi), whereas compressed natural gas (CNG) vehicles compress natural gas into an empty tank under 250 atmospheres (3,600 psi). Liquefied natural gas (LNG) vehicles operate at lower pressures but require significant insulation in the tank system to maintain the natural gas at minus-162 degrees Celsius (minus-260 degrees Fahrenheit) so that it remains liquid. Next-gen NG vehicles Long said that next-generation natural gas vehicles will require a material that binds the methane and packs it more densely into the fuel tank, providing a larger driving range. One of the major problems has been finding a material that absorbs the methane at a relatively low pressure, such as 35 atmospheres, but gives it all up at a pressure where the engine can operate, between 5 and 6 atmospheres. MOFs, which have a lot of internal surface area to adsorb gases—that is, for gas molecules to stick to the internal surfaces of the pores—and store them at high density, are one of the most promising materials for adsorbed natural gas (ANG) storage. “This is a big advance both in terms of capacity and thermal management,” Long said. “With these new flexible MOFs, you can get to capacities beyond what was thought possible with rigid MOFs.” Among the other advantages of flexible MOFs, Long says, is that they do not heat up as much as other methane absorbers, so there is less cooling of the fuel required. “If you fill a tank that has adsorbent, such as activated charcoal, when the methane binds it releases heat,” he said. “With our material, some of that heat goes into changing the structure of the material, so you have less heat to dissipate, less heat to manage. You don’t have to have as much cooling technology associated with filling your tank.” The flexible MOF material could perhaps even be placed inside a balloon-like bag that stretches to accommodate the expanding MOF as methane is pumped in, so that some of the heat given off goes into stretching the bag. Long and his colleagues at the National Institute of Standards and Technology and in Europe will publish their findings online in Nature. Improving on-board natural-gas storage Natural gas from oil wells is one of the cheapest and cleanest fossil fuels today, used widely to heat homes as well as in manufacturing and to produce electricity. It has yet to be widely adopted in the transportation sector, however, because of the expensive and large on-board compressed fuel tanks. In addition, gasoline packs over three times the energy density per volume as natural gas, even when compressed to 3,600 psi, which results in natural gas vehicles with a shorter driving range per fill-up. In order to advance on-board natural gas storage, Ford Motor Company teamed up with UC Berkeley on this project, with funding from the Advanced Research Projects Agency–Energy (ARPA-E) of the U.S. Dept. of Energy. Ford is a leader in CNG/propane-prepped vehicles with more than 57,000 sold in the U.S. since 2009, more than all other major U.S. automakers combined. According to Mike Veenstra, of Ford’s research and advanced engineering group in Dearborn, Michigan, Ford recognized that ANG has the potential to lower the cost of on-board tanks, station compressors and fuel along with serving to increase natural gas-powered vehicle driving range within the limited cargo space. “Natural gas storage in porous materials provides the key advantage of being able to store significant amounts of natural gas at low pressures than compressed gas at the same conditions,” said Veenstra, the principal investigator of this ARPA-E project. “The advantage of low pressure is the benefit it provides both on-board the vehicle and off-board at the station. In addition, the low-pressure application facilitates novel concepts such as tanks with reduced wall thicknesses along with conformable concepts which aid in decreasing the need to achieve the equivalent volumetric capacity of compressed CNG at high pressure.” Long has been exploring MOFs as gas adsorbers for a decade, hoping to use them to capture carbon dioxide emitted from power plants or store hydrogen in hydrogen-fueled vehicles, or to catalyze gas reactions for industry. Last year, however, a study by UC Berkeley’s Berend Smit found that rigid MOFs have a limited capacity to store methane. Long and graduate student and first author Jarad Mason instead turned to flexible MOFs, noting that they behave better when methane is pumped in and out. The flexible MOFs they tested are based on cobalt and iron atoms dispersed throughout the structure, with links of benzenedipyrazolate (bdp). Both cobalt (bdp) and iron (bdp) are highly porous when expanded, but shrink to essentially no pores when collapsed. Their first experiments on these compounds already surpass the theoretical limits for rigid MOFs, Long said. This is a fundamental discovery that now needs a lot of engineering to find out how best to take advantage of these new adsorbent properties.” He and his colleagues are also now developing flexible MOFs to store hydrogen. Source: Univ. of California, Berkeley http://www.rdmag.com/news/2015/10/better-way-pack-natural-gas-fuel-tanks

World's fastest nanoscale photonics switch

 

"Device" is a disc 250 nm in diameter that is capable of switching optical pulses at femtosecond rates (femtosecond is a one millionth of one billionth of a second). Credit: Maxim Scherbakov et al International team of researchers from Lomonosov Moscow State University and the Australian National University in Canberra created an ultrafast all-optical switch on silicon nanostructures. This device may become a platform for future computers and permit to transfer data at an ultrahigh speed. The article with the description of the device was published in Nano Letters journal and highlighted in Nature Materials. This work belongs to the field of photonics -- an optics discipline which appeared in the 1960-s, simultaneously with the invention of lasers. Photonics has the same goals as electronics does, but uses photons--the quanta of light--instead of electrons. The biggest advantage of using photons is the absence of interactions between them. As a consequence, photons address the data transmission problem better than electrons. This property can primarily be used for in computing where IPS (instructions per second) is the main attribute to be maximized. The typical scale of eletronic transistors--the basis of contemporary electronic devices--is less than 100 nanometers, wheres the typical scale of photonic transistors stays on the scale of several micrometers. Nanostructures that are able to compete with the electronic structures--for example, plasmonic nanoparticles--are characterized by low efficiency and significant losses. Therefore, coming up with a compact photonic switch was a very challenging task. Three years ago several groups of researchers simultaneously discovered an important effect: they found out that silicon nanoparticles are exhibit strong resonances in the visible spectrum -- the so-called magnetic dipole resonances. This type of resonance is characterized by strong localization of light waves on subwavelength scales, inside the nanoparticles. This effect turned out to be interesting to researches, but, according to Maxim Shcherbakov, the first author of the article published in Nano Letters, nobody thought that this discovery could create a basis for development of a compact and very rapid photonic switch. Nanoparticles were fabricated in the Australian National University by e-beam lithography followed by plasma-phase etching. It was done by Alexander Shorokhov, who served an internship in the University as a part of Presidential scholarship for studying abroad. The samples were brought to Moscow, and all the experimental work was carried out at the Faculty of Physics of Lomonosov Moscow State University, in the Laboratory of Nanophotonics and Metamaterials. "In our experimental research me and my colleague Polina Vabishchevich from the Faculty used a set of nonlinear optics methods that address femtosecond light-matter, -- explains Maxim Shcherbakov. -- We used our femtosecond laser complex acquired as part of the MSU development program." Eventually, researches developed a "device": a disc 250 nm in diameter that is capable of switching optical pulses at femtosecond rates (femtosecond is a one millionth of one billionth of a second). Switching speeds that fast will allow to create data transmission and processing devices that will work at tens and hundreds terabits per second. This can make possible downloading thousands of HD-movies in less than a second. The operation of the all-optical switch created by MSU researchers is based on the interaction between two femtosecond pulses. The interaction becomes possible due to the magnetic resonance of the silicon nanostructures. If the pulses arrive at the nanostructure simultaneously, one of them interacts with the other and dampers it due to the effect of two-photon absorption. If there is a 100-fs delay between the two pulses, the interaction does not occur, and the second pulse goes through the nanostructure without changing. "We were able to develop a structure with the undesirable free-carrier effects are suppressed, -- says Maxim Shcherbakov. -- Free carriers (electrons and electron holes) place serious restrictions on the speed of signal conversion in the traditional integrated photonics. Our work represents an important step towards novel and efficient active photonic devices-- transistors, logic units, and others. Features of the technology implemented in our work will allow its use in silicon photonics. In the nearest future, we are going to test such nanoparticles in integrated circuits." http://www.sciencedaily.com/releases/2015/10/151027143027.htm

The Tantalizing Links between Gut Microbes and the Brain

 

Neuroscientists are probing the idea that intestinal microbiota might influence brain development and behavior Nearly a year has passed since Rebecca Knickmeyer first met the participants in her latest study on brain development. Knickmeyer, a neuroscientist at the University of North Carolina School of Medicine in Chapel Hill, expects to see how 30 newborns have grown into crawling, inquisitive one-year-olds, using a battery of behavioural and temperament tests. In one test, a child's mother might disappear from the testing suite and then reappear with a stranger. Another ratchets up the weirdness with some Halloween masks. Then, if all goes well, the kids should nap peacefully as a noisy magnetic resonance imaging machine scans their brains. “We try to be prepared for everything,” Knickmeyer says. “We know exactly what to do if kids make a break for the door.” Knickmeyer is excited to see something else from the children—their faecal microbiota, the array of bacteria, viruses and other microbes that inhabit their guts. Her project (affectionately known as 'the poop study') is part of a small but growing effort by neuroscientists to see whether the microbes that colonize the gut in infancy can alter brain development. The project comes at a crucial juncture. A growing body of data, mostly from animals raised in sterile, germ-free conditions, shows that microbes in the gut influence behaviour and can alter brain physiology and neurochemistry. In humans, the data are more limited. Researchers have drawn links between gastrointestinal pathology and psychiatric neurological conditions such as anxiety, depression, autism, schizophrenia and neurodegenerative disorders—but they are just links. “In general, the problem of causality in microbiome studies is substantial,” says Rob Knight, a microbiologist at the University of California, San Diego. “It's very difficult to tell if microbial differences you see associated with diseases are causes or consequences.” There are many outstanding questions. Clues about the mechanisms by which gut bacteria might interact with the brain are starting to emerge, but no one knows how important these processes are in human development and health. That has not prevented some companies in the supplements industry from claiming that probiotics—bacteria that purportedly aid with digestive issues—can support emotional well-being. Pharmaceutical firms, hungry for new leads in treating neurological disorders, are beginning to invest in research related to gut microbes and the molecules that they produce. Scientists and funders are looking for clarity. Over the past two years, the US National Institute of Mental Health (NIMH) in Bethesda, Maryland, has funded seven pilot studies with up to US$1 million each to examine what it calls the 'microbiome–gut–brain axis' (Knickmeyer's research is one of these studies). This year, the US Office of Naval Research in Arlington, Virginia, agreed to pump around US$14.5 million over the next 6–7 years into work examining the gut's role in cognitive function and stress responses. And the European Union has put €9 million (US$10.1 million) towards a five-year project called MyNewGut, two main objectives of which target brain development and disorders. The latest efforts aim to move beyond basic observations and correlations—but preliminary results hint at complex answers. Researchers are starting to uncover a vast, varied system in which gut microbes influence the brain through hormones, immune molecules and the specialized metabolites that they produce. “There's probably more speculation than hard data now,” Knickmeyer says. “So there's a lot of open questions about the gold standard for methods you should be applying. It's very exploratory.” Gut reactions Microbes and the brain have rarely been thought to interact except in instances when pathogens penetrate the blood–brain barrier—the cellular fortress protecting the brain against infection and inflammation. When they do, they can have strong effects: the virus that causes rabies elicits aggression, agitation and even a fear of water. But for decades, the vast majority of the body's natural array of microbes was largely uncharacterized, and the idea that it could influence neurobiology was hardly considered mainstream. That is slowly changing. Studies on community outbreaks were one key to illuminating the possible connections. In 2000, a flood in the Canadian town of Walkerton contaminated the town's drinking water with pathogens such as Escherichia coli and Campylobacter jejuni. About 2,300 people suffered from severe gastrointestinal infection, and many of them developed chronic irritable bowel syndrome (IBS) as a direct result. During an eight-year study of Walkerton residents, led by gastroenterologist Stephen Collins at McMaster University in Hamilton, Canada, researchers noticed that psychological issues such as depression and anxiety seemed to be a risk factor for persistent IBS. Premysl Bercik, another McMaster gastroenterologist, says that this interplay triggered intriguing questions. Could psychiatric symptoms be driven by lingering inflammation, or perhaps by a microbiome thrown out of whack by infection? The McMaster group began to look for answers in mice. In a 2011 study, the team transplanted gut microbiota between different strains of mice and showed that behavioural traits specific to one strain transmitted along with the microbiota. Bercik says, for example, that “relatively shy” mice would exhibit more exploratory behaviour when carrying the microbiota of more-adventurous mice. “I think it is surprising. The microbiota is really driving the behavioural phenotype of host. There's a marked difference,” Bercik says. Unpublished research suggests that taking faecal bacteria from humans with both IBS and anxiety and transplanting it into mice induces anxiety-like behaviour, whereas transplanting bacteria from healthy control humans does not. Such results can be met with scepticism. As the field has developed, Knight says, microbiologists have had to learn from behavioural scientists that how animals are handled and caged can affect things such as social hierarchy, stress and even the microbiome. And these experiments and others like them start with a fairly unnatural model: germ-free—or 'gnotobiotic'—mice. These animals are delivered by Caesarean section to prevent them from picking up microbes that reside in their mothers' birth canals. They are then raised inside sterile isolators, on autoclaved food and filtered air. The animals are thus detached from many of the communal microbes that their species has evolved with for aeons. In 2011, immunologist Sven Pettersson and neuroscientist Rochellys Diaz Heijtz, both at the Karolinska Institute in Stockholm, showed that in lab tests, germ-free mice demonstrated less-anxious behaviour than mice colonized with natural indigenous microbes. (Less anxiety is not always a good thing, evolutionarily speaking, for a small mammal with many predators.) When the Karolinska team examined the animals' brains, they found that one region in germ-free mice, the striatum, had higher turnover of key neurochemicals that are associated with anxious behaviour, including the neurotransmitter serotonin. The study also showed that introducing adult germ-free mice to conventional, non-sterile environments failed to normalize their behaviour, but the offspring of such 'conventionalized' mice showed some return to normal behaviour, suggesting that there is a critical window during which microbes have their strongest effects. By this time, many researchers were intrigued by the mounting evidence, but results stemmed mostly from fields other than neuroscience. “The groups working on this are primarily gut folks, with a few psychology-focused people collaborating,” says Melanie Gareau, a physiologist at the University of California, Davis. “So the findings tended to describe peripheral and behavioural changes rather than changes to the central nervous system.” But Pettersson and Diaz Heijtz's research galvanized the field, suggesting that researchers could get past observational phenomenology and into the mechanisms affecting the brain. Nancy Desmond, a programme officer involved in grant review at the NIMH, says that the paper sparked interest at the funding agency soon after its publication and, in 2013, the NIMH formed a study section devoted to neuroscience research that aims to unravel functional mechanisms and develop drugs or non-invasive treatments for psychological disorders. Judith Eisen, a neuroscientist at the University of Oregon in Eugene, earned a grant to study germ-free zebrafish, whose transparent embryos allow researchers to easily visualize developing brains. “Of course, 'germ-free' is a completely unnatural situation,” Eisen says. “But it provides the opportunity to learn which microbial functions are important for development of any specific organ or cell type.” Chemical exploration Meanwhile, researchers were starting to uncover ways that bacteria in the gut might be able to get signals through to the brain. Pettersson and others revealed that in adult mice, microbial metabolites influence the basic physiology of the blood–brain barrier. Gut microbes break down complex carbohydrates into short-chain fatty acids with an array of effects: the fatty acid butyrate, for example, fortifies the blood–brain barrier by tightening connections between cells (see 'The gut–brain axis'). Recent studies also demonstrate that gut microbes directly alter neurotransmitter levels, which may enable them to communicate with neurons. For example, Elaine Hsiao, a biologist now at the University of California, Los Angeles, published research this year examining how certain metabolites from gut microbes promote serotonin production in the cells lining the colon—an intriguing finding given that some antidepressant drugs work by promoting serotonin at the junctions between neurons. These cells account for 60% of peripheral serotonin in mice and more than 90% in humans. Like the Karolinska group, Hsiao found that germ-free mice have significantly less serotonin floating around in their blood, and she also showed that levels could be restored by introducing to their guts spore-forming bacteria (dominated by Clostridium, which break down short-chain fatty acids). Conversely, mice with natural microbiota, when given antibiotics, had reduced serotonin production. “At least with those manipulations, it's quite clear there's a cause–effect relationship,” Hsiao says. But it remains unclear whether these altered serotonin levels in the gut trigger a cascade of molecular events, which in turn affect brain activity—and whether similar events take place in humans, too. “It will be important to replicate previous findings, and translate these findings into human conditions to really make it to the textbooks,” Hsiao says. For John Cryan, a neuroscientist at University College Cork in Ireland, there is little question that they will. His lab has demonstrated that germ-free mice grow more neurons in a specific brain region as adults than do conventional mice. He has been promoting the gut–brain axis to neuroscientists, psychiatric-drug researchers and the public. “If you look at the hard neuroscience that has emerged in the last year alone, all the fundamental processes that neuroscientists spend their lives working on are now all shown to be regulated by microbes,” he says, pointing to research on the regulation of the blood–brain barrier, neurogenesis in mice and the activation of microglia, the immune-like cells that reside in the brain and spinal cord. At the 2015 Society for Neuroscience meeting in Chicago, Illinois, this month, Cryan and his colleagues plan to present research showing that myelination—the formation of fatty sheathing that insulates nerve fibres—can also be influenced by gut microbes, at least in a specific part of the brain. Unrelated work has shown that germ-free mice are protected from an experimentally induced condition similar to multiple sclerosis, which is characterized by demyelination of nerve fibres. At least one company, Symbiotix Biotherapies in Boston, Massachusetts, is already investigating whether a metabolite produced by certain types of gut bacterium might one day be used to stem the damage in humans with multiple sclerosis. A move to therapy Tracy Bale, a neuroscientist at the University of Pennsylvania in Philadelphia, suspects that simple human interventions may already be warranted. Bale heard about Cryan's work on the radio programme Radiolab three years ago. At the time, she was researching the placenta, but wondered how microbes might fit into a model of how maternal stress affects offspring. In research published this year, Bale subjected pregnant mice to stressful stimuli. She found that it noticeably reduced the levels of Lactobacilli present in the mice's vaginas, which are the main source of the microbes that colonize the guts of offspring. These microbial shifts carried over to pups born vaginally, and Bale detected signs that microbiota might affect neurodevelopment, especially in males. In work that her group plans to present at the Society for Neuroscience meeting, Bale has shown that by feeding vaginal microbiota from stressed mice to Caesarean-born infant mice, they can recapitulate the neurodevelopmental effects of having a stressed mother. Bale and her colleagues are now wrapping up research investigating whether they can treat mice from stressed mums with the vaginal microbiota of non-stressed mice. The work, Bale says, has “immediate translational effects”. She points to a project headed by Maria Dominguez-Bello, a microbiologist at the New York University School of Medicine, in which babies born by means of Caesarean section are swabbed on the mouth and skin with gauze taken from their mothers' vaginas. Her team wants to see whether these offspring end up with microbiota similar to babies born vaginally. “It's not standard of care,” Bale says, “but I will bet you, one day, it will be.” Many are still sceptical about the link between microbes and behaviour and whether it will prove important in human health — but scientists seem more inclined to entertain the idea now than they have in past. In 2007, for example, Francis Collins, now director of the US National Institutes of Health, suggested that the Human Microbiome Project, a large-scale study of the microbes that colonize humans, might help to unravel mental-health disorders. “It did surprise a few people who assumed we were talking about things that are more intestinal than cerebral,” Collins says. “It was a little bit of leap, but it's been tentatively backed up.” Funding agencies are supporting the emerging field, which spans immunology, microbiology and neuroscience, among other disciplines. The NIMH has offered seed funding for work on model systems and in humans to probe whether the area is worth more-substantial investment, a move that has already brought more researchers into the fold. The MyNewGut project in Europe has an even more optimistic view of the value of such research, specifically seeking concrete dietary recommendations that might alleviate brain-related disorders. Today, Knickmeyer's project on infants represents what she calls “a messy take-all-comers kind of sample”. Among the brain regions that Knickmeyer is scanning, the amygdala and prefrontal cortex hold her highest interest; both have been affected by microbiota manipulations in rodent models. But putting these data together with the dozens of other infant measures that she is taking will be a challenge. “The big question is how you deal with all the confounding factors.” The children's diets, home lives and other environmental exposures can all affect their microbiota and their neurological development, and must be teased apart. Knickmeyer speculates that tinkering with microbes in the human gut to treat mental-health disorders could fail for other reasons. Take, for instance, how microbes might interact with the human genome. Even if scientists were to find the therapeutic version of a “gold Cadillac of microbiota”, she points out, “maybe your body rejects that and goes back to baseline because your own genes promote certain types of bacteria.” There is much more to unravel, she says. “I'm always surprised. It's very open. It's a little like a Wild West out there.” This article is reproduced with permission and was first published on October 14, 2015.   http://www.scientificamerican.com/article/the-tantalizing-links-between-gut-microbes-and-the-brain/?WT.mc_id=SA_HLTH_20151027

Scott Kelly Prepares For a Spacewalk

 

Expedition 45 Commander Scott Kelly tries on his spacesuit inside the U.S. Quest airlock of the International Space Station. Kelly and Flight Engineer Kjell Lindgren will venture outside the station for a pair of spacewalks, the first of their careers, on Wednesday, Oct. 28 and Friday, Nov. 6.

The Oct. 28 spacewalk is set to last six hours and 30 minutes after Kelly and Lindgren set their spacesuits to battery power. It will be the 32nd U.S. spacewalk, and will focus on station upgrades and maintenance tasks, including installing a thermal cover on the Alpha Magnetic Spectrometer, which is a state-of-the-art particle physics detector that has been attached to the station since 2011. NASA TV coverage will begin at 6:30 a.m. EDT.

Sharing this photograph of the spacesuit fit check with his social media followers, Kelly wrote, "Day 212 Getting my game face on for #spacewalk Thanks for sticking w me #GoodNight from @space_station! #YearInSpace"

Image Credit: NASA

Last Updated: Oct. 27, 2015

Editor: Sarah Loff

Scientists turn tomatoes into efficient medicinal compound factories

 

The John Innes Center research could lead to industrial level production of certain medically-beneficial natural compounds (Credit: John Innes Center) A team from the John Innes Center in the UK has developed a method for producing large quantities of beneficial compounds by growing them in tomatoes. Given how high yielding the fruit is, it could be used to produce the substances on an industrial scale. The compounds in question are phenylpropanoids. They include substances likeResveratrol – which is found in wine, and has been shown to extend lifespan in animals – and Genistein – found in soybeans and thought to be useful for prevention of certain cancers. To get tomatoes to produce the substances, the researchers turned to a common garden plant known as Arabidopsis thaliana. It contains a protein called AtMYB12, which activates genes responsible for switching on metabolic pathways than in turn produce the natural compounds. The more of the protein that's present, the more of the compounds is produced. Interestingly, when introduced into tomato plants, AtMYB12 didn't only increase the amount of the compounds produced, but also increased the amount of energy that the plant dedicated to producing them, making it an extremely effective phenylpropanoids factory. In fact, a single tomato contained as much Resveratrol as you'd find in 50 bottles of wine, and as much Genistein as present in 2.5 kg of tofu. When you consider that tomatoes are a very high yielding crop, producing as much as 500 tonnes per hectare (551 tons per 2.5 acres), the method could be a better alternative to lab-based artificial synthesis. "Our study provides a general tool for producing valuable phenylpronanoid compounds on an industrial scale in plants, and potentially production of other products derived from aromatic amino acids," says study lead Dr Yang Zhang. "Our work will be of interest in different research areas including fundamental research on plants, plant/microbe engineering, medicinal plant natural products, as well as diet and health research." The team believes that its work with tomato plants provides a solid platform for quickly and conveniently producing the medicinal compounds, and claims that, given a little adjustment, the method could also be used to create other such compounds. The findings of the study were published in the journal Nature Communications. Source: John Innes Center http://www.gizmag.com/tomatoes-beneficial-natural-compound-production/40049

Wendelstein 7-x stellarator puts new twist on nuclear fusion power

 

The outside of the Wendelstein 7-x stellarator with its conglomeration of equipment, ports, and supporting structure (Credit: IPP, Bernhard Ludewig) In a large complex located at Greifswald in the north-east corner of Germany, sits a new and unusual nuclear fusion reactor awaiting a few final tests before being powered-up for the very first time. Dubbed the Wendelstein 7-x fusion stellarator, it has been more than 15 years in the making and is claimed to be so magnetically efficient that it will be able to continuously contain super-hot plasma in its enormous magnetic field for more than 30 minutes at a time. If successful, this new reactor may help realize the long-held goal of continuous operation essential for the success of nuclear fusion power generation. Created by the Max Planck Institute for Plasma Physics (IPP) and designed with the aid of a supercomputer, the Wendelstein 7-x is the first large-scale optimized stellarator of its type ever to be commissioned. With a name like something out of Hitchhiker's Guide to the Galaxy and a containment vessel that literally provides a new twist on the doughnut shape we see in standard tokamakfusion reactors, the quirky stellarator design aims to provide an inherently more stable environment for plasma and a more promising route for nuclear fusion research in general. Initially an American design conceived by Lyman Spitzer working at Princeton University in 1951, the stellarator was deemed too complex for the constraints of materials available in the middle of the 20th Century, and the more easily constructed toroid of the tokamak won out as the standard model for fusion research. Though some stellarators have been constructed over the course of time – notably the predecessor to this latest iteration known as the Wendelstein 7-AS (Advanced Stellarator) – the calculations required to ensure ultimate plasma containment and control have only become possible with the advent of supercomputers. As such, algorithms specifically created to fuse theory and practice have now been applied to the design of the Wendelstein 7-x, and its designers firmly believe that this latest version will have the stability required to be the precursor machine to full-blown, continuous nuclear fusion power generation. For the eventual success of nuclear fusion power (essentially where two isotopes of hydrogen, deuterium and tritium, are subject to such energy that the strong nuclear force is overcome and they fuse to form helium and release copious amounts of neutron energy), stability is essential. This is because the enormous pressures and temperatures (around 100 million degrees Celsius (180 million F)) used to create the plasma, and then accelerate the resulting ion and electron soup around the containment vessel, means that any instability in the magnetic containment field or the pressure vessel itself will result in degradation and ultimately the failure of the process. To achieve a more stable environment, the stellarator eschews the method of inducing current through the plasma to drive electrons and ions around the inside of the vessel as found in tokamak designs, instead relying entirely on external magnetic fields to move the particles along. In this way, stellarator designs are basically immune to the sudden and unexpected disruptions of plasma and the enormous – and often destructive – magnetic field collapses that sometimes occur in tokamaks. As such, a stellarator reactor is able to hold the plasma in a containment field that twists through a set of magnetic coils to continuously hold the plasma away from the walls of the device. This is because, in a normal tokamak, with its doughnut-shaped containment vessel and electromagnet windings that loop through the center of the toroid and around the outside, the magnetic field is stronger in the center than it is on the outer side. This means that plasma contained in a tokamak tends to drift to the outer walls where it then collapses. The stellarator, on the other hand, avoids this situation by twisting the entire containment vessel into a shape that constantly forces the plasma stream into the center of the reactor vessel as it continuously encounters magnetic fields in opposing positions along its entire length. The advantages of the stellarator over the tokamak come at a cost, however, as the many twists and turns that give the stellarator an advantage in magnetic containment also means that many particles can simply be lost as they veer off course following the path of the containment vessel itself. To help avoid this, a great many more magnetic coils are required for the stellarator and must be set up at very close intervals around the structure and super-cooled with liquid helium for maximum efficiency. In the case of the Wendelstein 7-x, the weight of the 50, 3.5-meter (11.5-ft) tall non-planar super-conducting electromagnets alone is around 425 tonnes (468 tons) and their placement makes construction difficult and their assembly fraught with problems. Not to mention the fact that piping around vast quantities of liquid helium to ensure that the electromagnets superconduct at temperatures close to absolute zero makes the Wendelstein 7-x a plumber's nightmare, and a tricky addition to an already difficult balancing act. As such, the physical design of the stellarator itself requires access ports for fuel ingress and egress, along with a myriad other entry points for instruments, sensors, and all the other necessary paraphernalia necessary to monitor the enormous pressures, voltages, and temperatures that it will be subject to in operation. Despite all of these problems, tests on the completed stellarator to maintain the sub-millimeter accuracy for the plasma path are progressing and show promise. In one recent test, an electron beam was injected into the stellarator and progressed along a predetermined field line in the circular tracks through the evacuated plasma vessel. As it moved through the machine, the beam created a tracer in its wake created by collisions with electrons contained in the residual gas in the vessel. Meanwhile, as the electron beam constantly circulated through the system, a fluorescent rod was pushed transversely through the vessel in cross section, and when the electron beam struck the rod, visible spots of light were created and the results recorded with a camera. In this way, the whole cross section of the magnetic field was gradually made visible. "Once the flux surface diagnostics were placed in operation, we were immediately able to see the first magnetic surfaces," said Dr. Matthias Otte, the man responsible for this measurement process. "Our images clearly show how magnetic field lines create closed surfaces in many toroidal circulations." Whilst in itself just another stepping stone toward the ultimate goal of practical fusion energy, the IPP stellarator is an important juncture in the field. With tokamak-based reactors still requiring more energy in than they actually produce, both the scientific and general public alike have grown wary of the long-held promises surrounding nuclear fusion. And, though many bodies, such as the University of Washington, Lockheed-Martin, and MIT, claim to be "close" to producing a working, sustainable, self-powering machine, nuclear fusion still remains a pipe dream. This is where IPP's proving of the technology over the coming months leading to a full-blown commissioning of the machine may well provide the nexus between theory and practicality and, if not deliver on the promise of boundless energy, at least provide a proof of concept and renew flagging interest in a field that may, one day, solve all of our energy needs. With approval to continue from nuclear regulators in Germany expected by the end of this month, the Wendelstein 7-x stellarator is slated for its first fully-operational tests in November this year. At a cost of more than €1 billion ($US 1.1 billion) and over 1 million man-hours of work committed so far, the hopes of Europe's future being a nuclear fusion-powered one may well rest on the ability of this machine to perform as expected. Watch this space. Source: IPP   http://www.gizmag.com/wendelstein7x-fusion-stellarator-plasma-tests/40014/