eNature - Celebre o dia da árvore com a EDP

Escolha uma árvore, agite o telemóvel e veja-a crescer. Plantá-la é ainda mais divertido! Seja criativo e escolha um local original.

Desde 21 de março, dia da árvore, plante as árvores que quiser e partilhe-as com os seus amigos no Facebook.

Descarregue gratuitamente a aplicação eNature e comece a plantar.

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Apple link:

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Depois do treino é só passar à vida real.

Fonte: http://www.eco.edp.pt/

A Battery That Charges in Seconds

Quick charge. A new type of battery could allow electric vehicles to charge in the same amount of time it takes to fill a tank of gas

Imagine being able to charge your cell phone in a matter of seconds or your laptop in a few minutes. That might soon be possible, thanks to a new kind of nanostructured battery electrode developed by scientists at the University of Illinois, Urbana-Champaign. The researchers found that their electrode can charge and discharge up to 100 times faster than existing devices while holding the same amount of energy.

High-storage batteries that could charge and discharge quickly might make a number of still-marginal technologies much more attractive. For example, if you could recharge an electric car in minutes rather than hours, filling up your battery at a charging station would take no longer than the amount of time it takes to buy a tank of gas. And batteries that gave up their stored energy quickly could mean uninterrupted solar power, pitching in when the sun goes behind a cloud and solar cells stop producing.


Electrical storage devices known as capacitors charge and discharge very quickly, but because they hold their charge on the surface of metal plates, their storage capacity is limited. Batteries, on the other hand, can store much more energy because they hold their charge inside the bulk of a material, usually an oxide or a phosphate compound located inside the cathode. Unfortunately, because these materials are not good conductors of electric charge, it takes a long time to get the charge in or out of a battery.

Scientists have tried to get around this problem in the past by adding electrical conductors to the energy-storage material, but this reduces the material’s volume, so it tends to lower the battery’s capacity. University of Illinois materials scientist Paul Braun and his colleagues came up with a novel solution, published online this month in Nature Nanotechnology. They built a tiny metal lattice with so many nooks and crannies that when it’s filled with a charge-storage material, the electrons in the material never have far to go before reaching the metal and being conducted away.

The Illinois researchers made their electrode by coating a surface with tiny polystyrene spheres just a few hundred nanometers across, packing the spheres together into a regular lattice structure. Then they filled the gaps between the spheres with nickel and dissolved the polystyrene. That left a three-dimensional metal scaffold, which they thinned down so that the metal made up just 6% of the total volume, and they then coated a thin film of the storage material onto the scaffold. The team used this technique to make cathodes for lithium-ion and nickel-metal hydride batteries, with the former used in many consumer electronics devices such as laptops and cell phones whereas the latter are used in many electric vehicles.

Braun and his co-workers found that the lithium-ion battery could charge and discharge between 10 and 100 times more quickly than the fastest devices on the market today. Its storage capacity was actually slightly larger than normal (by about 10% to 20%). And because every step of their manufacturing process is used in industry today, the researchers say there should be no major problems with incorporating their cathodes into commercial batteries. They just need to show how to scale up their technology—so far they’ve tried it only on watch-size batteries. “I have every reason to believe we can scale up,” says Braun, “and we are looking to partner with the right people to do that.”

However, materials scientist Yury Gogotsi of Drexel University in Philadelphia, Pennsylvania, sounds a note of caution. Although he says the latest work shows the importance of a smart electrode design that uses common materials, he questions how long the batteries can withstand continued charging and recharging over such short intervals. He is also less sanguine about scaling up. "Braun's group provides an advantage in rate performance," he says. "The next step will be to find a simpler way of making three-dimensional electrodes."

Source: www.news.sciencemag.org

Mexilhões inspiram produção de adesivo

Os mexilhões, moluscos bivalves que aderem às rochas, produzem fibras muito resistentes, o bisso, que utilizam como cola, não perdendo a sua resistência mesmo em zonas de forte rebentação e agitação marítima.


Após estas fibras terem sido analisadas, foram replicadas em laboratório pela Universidade de Chicago, que desenvolveu um novo adesivo, resistente e flexível, que poderá ser utilizado em máquinas subaquáticas e em cirurgias, como agente de ligação em implantes.

Este adesivo tem rigidez e resistência ajustáveis através da variação do pH ou do uso de diferentes iões metálicos na sua produção e, para ainda melhorar as vantagens do seu uso, é um adesivo amigo do ambiente, porque é produzido apenas a partir de produtos naturais.

Fonte: http://www.mundodosanimais.com/

Banana peel can purify water, say scientists

Banana peels can be used to purify drinking water contaminated with toxic heavy metals such as copper and lead, according to a study.


Researchers from the Bioscience Institute at Botucatu, Brazil, said that the skins can outperform even conventional purifiers such as aluminium oxide, cellulose and silica. These have potentially toxic side effects and are expensive.
The team's method follows previous work that showed that plant parts, such as apple and sugar cane wastes, coconut fibres and peanut shells, can remove toxins from water.


These natural materials contain chemicals that have an affinity for metals.

"I was at home eating bananas when I had the idea: 'Why not make something with this?'" Gustavo Rocha de Castro, a researcher at the institute and co-author of this study, told SciDev.Net.

De Castro and colleagues dried the peels in the sun for a week, ground them and added them to river water containing known concentrations of copper and lead. They found that the peels absorbed 97 per cent of the metals after just one hour.

The peels were tested in the lab and worked perfectly. Eventually their efficiency reduces, at which point the metals should be removed from the skins so that they can be disposed of safely.

Castro said that, although the peels were tested only on copper and lead, the material could also work on cadmium, nickel and zinc.

But he warned that this sort of filter is better suited to industrial purposes and cannot be used for water purification at home as the extraction capacity of banana skins depends on the particle size of the heavy metals — and this is difficult to measure.

Dimitris Kalderis, a wastewater treatment expert at the Department of Environmental Engineering in the Technical University of Crete, Greece, said: "The results are very promising, and the banana peel process has proven to be a cost-effective and quick alternative to conventional methods".

"I think that a small automated system to use either at home or at a central point for multiple families could be developed. The knowledge is there, what we need right now is innovation and construction."

The study was published in Industrial & Engineering Chemistry Research last month (16 February).

Source: http://www.scidev.ne

Lançamento oficial do Ano do Morcego e do site do Ano do Morcego (...e porque não?)

No dia 2 de Março, teve lugar na Lapa da Canada, em Nascentes do Alviela, a cerimónia de lançamento do Ano do Morcego, que contou com a presença do Secretário de Estado do Ambiente. Simultaneamente foi divulgado o site português do Ano do Morcego.

http://www.wix.com/anodomorcego/icnb


A actividade contou com uma visita a uma gruta onde já foram identificadas 12 espécies de morcegos e que alberga colónias de maternidade de várias espécies, sendo um dos abrigos subterrâneos mais importantes do país.
A Convenção de Bona e o EUROBATS declararam os anos de 2011 e 2012 como o Ano do Morcego. Esta campanha será dinamizada em Portugal pelo ICNB.


Estas comemorações têm um papel importante na divulgação da importância dos morcegos e dos desafios de conservação que enfrentam, de modo a melhorar a sua imagem e contribuir para a sua conservação e para a conservação dos habitats e ecossistemas de que dependem.

Existem mais de 1100 espécies de morcegos no mundo, totalizando cerca de um quinto de todos os mamíferos. Em Portugal são actualmente conhecidas 27 espécies de morcegos, que correspondem a mais de um terço das espécies de mamíferos que ocorrem no território. São todas protegidas e muitas delas ameaçadas de extinção.

Para além de legislação nacional os morcegos portugueses estão protegidos pela Directiva Habitats na União Europeia, pela Convenção de Berna do Conselho da Europa, e pela Convenção de Bona sobre as Espécies Migradoras. No âmbito da Convenção de Bona foi adoptado um Acordo orientado para a conservação das espécies de morcegos, que Portugal acompanha activamente: o EUROBATS – Acordo sobre a Conservação das Populações de Morcegos Europeus.



Fonte: www.portal.icnb.pt

CHECKLIST DA FLORA DE PORTUGAL (Continental, Açores e Madeira)

Foi concluída em Setembro de 2010 a Checklist da Flora de Portugal (Continente, Açores e Madeira). Trabalharam na sua revisão 18 autores sob a coordenação da Associação Lusitana de Fitossociologia (ALFA).


A Checklist da Flora de Portugal (Continental, Açores e Madeira) revê toda a flora vascular de Portugal com base em critérios taxonómicos e nomenclaturais, publicados em obras de referência, elencando um total de 3995 taxa dos quais 3314 ocorrem em Portugal continental, 1006 no arquipélago dos Açores e 1233 no arquipélago da Madeira.

Para além de inventariar a flora vascular de Portugal, esta lista contém ainda informações respeitantes à naturalidade e à protecção legal dos taxa.

Esta lista de referência da flora portuguesa é um contributo inestimável no processo de actualização do inventário da biodiversidade presente no território nacional, integrado no Sistema de Informação sobre o Património Natural (SIPNAT), constituindo um relevante instrumento de trabalho, e a base para a elaboração da Lista Vermelha da flora vascular.

A ALFA disponibiliza a Checklist da Flora de Portugal (Continental, Açores e Madeira) na sua página web, para onde podem ainda ser enviados comentários, sugestões ou correcções. Uma versão em pdf do documento também pode ser obtida após inscrição.

Página da ALFA: http://www3.uma.pt/alfa/checklist_flora_pt.html

Fonte: www.portal.icnb.pt

Melting Ice Sheets Now Largest Contributor To Rising Sea Levels

In a time like this while we are all in awe due to what has just happened in Japan, it is good to remember a bit of all the wrong things humans are doing which in a way or another are contributing for the convulsions of our planet.

Ice sheets are now the largest contributor to rising sea levels, a new report has found. If ice sheets continue to melt at their current rates, sea levels may rise over 12 inches in the next four decades.

The study was conducted over the course of 20 years, and the results will be published in the journal Geophysical Research Letters. The group of researchers examined monthly satellite measurements between 1992 and 2009, using climate model data. The research shows that in 2006, Greenland and Antarctic ice sheets lost a combined mass of 475 gigatonnes -- this ice loss can raise the global sea level by 1.3 millimeters per year.

Unfortunately, 2006 was not just a fluke occurrence. As Science Daily explains, ice sheets are melting at a steadily increasing rate. Over the course of the study, the ice sheets lost about an additional 36 gigatonnes per year, compared to each year before.

Melting ice caps have often taken the spotlight, but melting ice sheets are now dwindling at a faster rate than the ice caps and glaciers. While ice sheets extend for over 20,000 square miles, ice caps are defined as areas of less than 20,000 square miles. Though melting ice caps are certainly worthy of concern, their rate of loss has been three times smaller than the acceleration rate at which ice sheets are melting.

The report’s lead author, Eric Rignot of NASA’s Jet Propulsion Laboratory, is not surprised that ice sheets will now contribute the most to sea level rise. But, Rignot remarks, “What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007.” The trends suggest that by 2050, melting ice sheets could raise sea levels by nearly six inches -- this amount is then added to predictions for melting ice caps and ocean thermal expansion. The resulting calculations find that sea levels could rise 12.6 inches by 2050.

How would these rising sea levels affect us? Another recent study, reported in the journal Climate Change Letters, shows that rising sea levels may threaten over 1000 cities all around the globe by 2100. This study was based on projections that sea levels will rise by about three feet within the next century. Cities such as Miami, New Orleans, and Virginia Beach are expected to lose over 10 percent of their land. New York and Washington D.C. are also expected be impacted, though to a lesser degree. Other countries like The Maldives are expected to be completely erased from the face of the Earth.

U.N. reports have predicted that because of climate change, the world will have 50 million environmental refugees by 2020. That’s less than 10 years from now.

Source: http://www.huffingtonpost.com/