Why lithium-ion-batteries fail.


Materials in lithium ion battery electrodes expand and contract during charge and discharge. These volume changes drive particle fracture, which shortens battery lifetime. A group of ETH scientists together with colleagues from PSI quantify this effect for the first time using high-resolution 3D movies recorded using x-ray tomography at the Swiss Light Source.

https://i2.wp.com/cdn.physorg.com/newman/gfx/news/2013/whylithiumio.jpg

Lithium-ion batteries are in our cellphones, laptops, and digital cameras. Few portable electronic devices exist that do not rely on these energy sources. Currently battery electrodes contain active known as intercalation compounds. These materials store charge in their chemical structure without undergoing substantial structural change. That makes these batteries comparatively long-lived and safe. However, intercalation materials have one drawback: their limited energy density, the amount of energy they can store per volume and mass.

In the search for higher energy density batteries, scientists have experimented for more than 20 years with materials capable of repetitively alloying and de-alloying with lithium. Laboratory-scale experiments have shown that batteries with such materials have energy densities multiple times that of intercalation materials; however, these alloying materials are not yet exploited in industry because their lifetime is limited. Martin Ebner, Ph.D. student at the Laboratory for Nanoelectronics in the Department of Information Technology and Electrical Engineering (D-ITET) explains: “their capacity typically fades after a couple of charging and discharging cycles.” This is attributed to a massive – up to threefold – expansion of the material during charging. During discharge, the materials contract again, but do not reach their original state. Electrode break apart, the electrode structure disintegrates, and the fragments loose contact to the rest of the cell.

Batteries x-rayed during operation

To better understand this complex electrochemical and mechanical degradation of the electrode and to gain insight into how to develop better batteries, Martin Ebner and ETH-Professor Vanessa Wood, head of the Laboratory for Nanoelectronics at D-ITET, recognized the need to study a battery electrode non-invasively during operation. To do so, they turned to an imaging tool developed by ETH-Professor Marco Stampanoni. Professsor Stampanoni, holds a faculty position at the Institute for Biomedical Engineering at D-ITET and runs the tomographic x-ray microscopy beamline at the Swiss Light Source, the synchrotron facility at the Paul Scherrer Institute. The spectrally pure and intense synchrotron x-ray radiation enables the fast acquisition of high-resolution x-ray images that can be computationally assembled into three-dimensional movies.

The researchers observed the inside of the battery as it charged and discharged over 15 hours. They gathered unique, three-dimensional movies that capture the degradation mechanisms occurring in the battery and quantified the processes occurring within every particle for the thousands of particles in the electrode. The results of this study will be published in the journal Science; a pre-print version is available online at Science Express.

Irreversible structural changes

The data illustrate that tin oxide (SnO) particles expand during charging due to the influx of lithium ions causing an increase in particle volume. The scientists demonstrate that material lithiation happens as a core-shell process, progressing uniformly from the particle surface to the core. The material undergoing this reaction expands linearly with the stored charge. The x-ray images show that charging destroys the particle structure irreversibly with cracks forming within the particles. “This crack-formation is not random,” emphasizes Ebner. Cracks grow at locations where the crystal lattice contains preexisting defects. During discharge, the particle volume decreases; however, the material does not reach its original state again; the process is therefore not completely reversible.

The volume change of the individual particles drives expansion of the entire electrode from 50 micrometers to 120 micrometers. However, during discharge, the electrode contracts only to 80 micrometers. This permanent deformation of the electrode demonstrates that the polymer binder that holds the electrode together is not yet optimized for high volume expansion materials. This is critical for because deformation of the binder causes individual particles to become disconnected from the electrode and the battery looses capacity.

In addition to demonstrating that x-ray tomographic microscopy provides insight into morphological changes in the particles and electrodes, the researchers show that this technique can also be used to obtain quantitative and spatially resolved chemical information. For example, the researchers analyze chemical composition throughout the battery electrode to look at differences in lithiation dynamics at the single particle level and compare this to the average particle behavior. This approach is essential to understanding the influence of particle size, shape, and electrode homogeneity on battery performance.

Such insights into the operation of a battery would not be possible without the highly advanced x-ray tomography setup at the Swiss Light Source. “Visualizing batteries in operation was essentially impossible until recent advances in x-ray tomography. Thanks to the world class facilities developed by Professor Stampanoni and his team, we can watch the battery at work,” adds Wood enthusiastically.

Alternatives to crystalline materials

The researchers chose crystalline tin oxide as a model material because it undergoes a series of complex transformations also present in other materials, enabling deeper understanding into the behavior of a variety of materials. The insights provide the basis for developing new electrode materials and electrode structures that are tolerant to volume expansion. For Prof. Wood the results of this work indicate the benefit of using amorphous or nanostructured materials instead of crystalline ones. “On the quest for new materials, one must also bear in mind that they are only of industrial interest if they can be produced in large quantities at a low cost. However, amorphous and nanostructured materials offer a sufficient playground for innovation.” emphasizes Wood.

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Beijing car ban to tackle pollution.


Beijing to restrict private car use to tackle pollution.

Vehicles drive on the Third Ring Road on a very hazy winter day in Beijing
Beijing has more than four million private cars, considered to be a major source of the city‘s air pollution

China’s capital, Beijing, has announced measures to combat worsening air pollution, state-run media report.

They include taking half of the city’s four million private cars off the roads on days when there are serious levels of pollution.

The system will be based on a vehicle’s licence plate – odd numbers will be allowed on the roads one day, even numbers the next.

Motor vehicles are considered a major source of pollution.

The new system will give out four different degrees of air pollution warning – blue, yellow, amber and red, Xinhua news agency reports.

On days when an amber warning is given, factories will stop production and work will be halted on construction and building sites.

Restaurants which offer an open-air barbecue will be ordered to close temporarily and fireworks will be banned throughout the city.

Anger at exemptions

When a red warning is issued, the new car restriction measure will be implemented. Schools and kindergartens will also be closed.

The measure to restrict the number of private cars from using the road is proving to be controversial.

Critics have aired their concern that those who can afford to buy two or more cars will able to drive any day when the restriction is in force.

Users of Weibo, China’s version of Twitter, have also criticised the restriction for targeting ordinary people as cars used by government officials and civil servants are exempted.

One user said that whenever there is a problem in Beijing, “ordinary people are the first to be forced to pay the price for it”.

Beijing has almost 21 million permanent residents, according to official estimates.

There is also a large migrant population in the city, but no exact official figures are available.

Most people relied on bicycles and public transport to get around in the city before private car ownership became popular.

The growth of global immunisation.


http://mobile.bbc.co.uk/news/health-24519949

Li-Fi to replace Wi-Fi in China?


Chinese scientists have successfully developed a new cheaper way of getting connected to internet by using signals sent through light bulbs instead of radio frequencies as in Wi-Fi, a move expected to radically change process of online connectivity.

Four computers can be connected to internet through one- watt LED bulb using light as a carrier instead of traditional radio frequencies, as in Wi-Fi, said Chi Nan, an information technology professor with Shanghai‘s Fudan University.

Under the new discovery dubbed as ‘Li-Fi‘, a light bulb with embedded microchips can produce data rates as fast as 150 megabits per second, which is speedier than the average broadband connection in China, said Chi, who leads a Li-Fi research team including scientists from the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences.

The term Li-Fi was coined by Harald Haas from the University of Edinburgh in the UK and refers to a type of visible light communication technology that delivers a networked, mobile, high-speed communication solution in a similar manner as Wi-Fi.

With Li-Fi cost-effective as well as efficient, netizens should be excited to view 10 sample Li-Fi kits that will be on display at the China International Industry Fair that will kick off on November 5 in Shanghai.

The current wireless signal transmission equipment is expensive and low in efficiency, Chi said.

“As for cell phones, millions of base stations have been established around the world to strengthen the signal but most of the energy is consumed on their cooling systems,” she said.

“The energy utilisation rate is only 5 per cent,” state-run Xinhua news agency quoted her as saying.

Li-Fi was touted as a boon to China netizen community, the highest in the world with about 600 million connections.

Compared with base stations, the number of light bulbs that can be used is practically limitless.

Meanwhile, Chinese people are replacing the old-fashioned incandescent bulbs with LED light bulbs at a fast pace.

“Wherever there is an LED light bulb, there is an internet signal. Turn off the light and there is no signal,” Chi said.

However, there is still a long way to go to make Li-Fi a commercial success.

“If the light is blocked, then the signal will be cut off,” Chi said.

More importantly, according to the scientist, the development of a series of key related pieces of technology, including light communication controls as well as microchip design and manufacturing, is still in an experimental period.

Stop smoking, stay good-looking.


If bad lungs don't scare you then this should. Screenshot: tobaccobody.fi
If bad lungs don’t scare you then this should.
A public health agency in Finland is using an interesting approach to shock teens into not smoking

The Tobacco Body website features an interactive image of a man and a woman. Users zoom in and out of their body parts to observe the effects smoking has on a male and female body.

This is a new campaign by the Cancer Society of Finland, whose objective, according to the website of their ad agency, is to use this as a tool to show teenagers “to think critically about smoking.” The idea is to move beyond the black lungs, gooey tar and damaged livers, and use technology to “make the shock effect more shocking.”

And pretty shocking it is. Before-lady and Before-man are indeed much better-looking than After-lady and the After-man.

The strategy employed is clear: teens today don’t care about lungs, livers and cancer, or if they do, the constant exposure to such warnings has rendered them ineffective. What they do care about is appearances. So let’s show them how ugly smoking makes them.

On one hand you can’t argue with facts: smoking does give you spots, increase your testosterone levels, give you bad breath and unhealthy hair, yellow your teeth and nails, etc. Fact-wise there’s not much to dispute in the Tobacco Body website. But how advisable is it to resort to telling teenagers what is beautiful/popular/acceptable and what is not, even if it is towards the noble cause of telling them to not smoke?

Sample these snippets taken from the website:

[Man & Woman] “Dear Smoker, we’re sorry to inform you that according to nail fashion experts, nicotine yellow is not this season’s colour.”

[Woman] “Hey non-smoking girl, you are on a wonder-diet and you don’t even know it! Your body shape is closer to the average, whereas research shows that smokers weigh more and are rounder around the abdominal area.”

[Woman] “The non-smoking woman is less-likely to have as much hair growing on her arms as a smoker.”

[Woman] “The non-smoking woman usually has no additional hairs growing under her nose… No need for a five-bladed special razor.”

[Man & Woman] “Smokers have bad breath. As many as 20 per cent of people have ended relationships because of smoking. In Burn Magazine’s interviews several celebrities reveal they prefer kissing non-smokers.”

[Man & Woman] “A weary face is not a popular one: out of the 100 most popular profile pictures in a dating service only 2 were pictures of smokers.”

Basically, the Cancer Society of Finland is telling youngsters that smoking makes you hairy, fat, yellow-toothed and gives you bad breath. I found it slightly bothersome how features that are quite normal in several healthy teenagers, like rounded abdomens and hair on arms (for women), was being grouped with those which are blatantly undesirable and unhealthy, like yellowing teeth, bad breath and damaged lungs.

I wondered if this ad could be sending negative body image messages to kids who are naturally fat or hairy – are they implying that these kids are not as desirable?

But the more I thought about it the harder I realised it was to completely buy into that line of reasoning. Because, as a friend pointed out, this may be a case where the end could perhaps justify the means.

It was different in the case of the Dove ‘You’re more beautiful than you think you are’ campaign which also used a similar strategy to sell their product. They too inadvertently (?) went about setting definitions for beauty. The glaring difference of course was that Dove, at the end of the day, was trying to sell us soap under the guise of the noble motive of wanting women to feel good about themselves.

In the case of Tobacco Body, there’s no such deception. As questionable as their strategy might be, we can probably be sure that all this campaign wants is for teenagers to say no to smoking. They are, after all, the Cancer Society of Finland.

MSF presisent tours india on Cycle.


http://www.cycleformsf.in/unnicycles/

Himalayan mystery solved? The Yeti existed, finds British geneticist


One of the greatest mysteries of the Himalayas may have finally been solved.

Genetic testing has led scientists to believe that the abominable snowman – the Yeti, actually existed but it was actually a cross between an ancient polar bear and brown bear.

 Hair samples from what is believed to be that of the Yeti have been found to genetically match that of an ancient polar bear dating back 120,000 years.

Bryan Sykes, professor of human genetics at Oxford University, conducted the research.

Dr Sykes has over many years assembled substantial physical evidence, which he has subjected to the most sophisticated DNA tests available, to answer scientifically the mystery of Bigfoot.

The professor said “This is an exciting and completely unexpected result”.

Dr Sykes however said the finding does not mean ancient polar bears are still wandering around the Himalayas.

“But it could mean there is a sub species of brown bear in the high Himalayas which descended from the bear that was the ancestor of the polar bear. Or it could mean there has been more recent hybridisation between the brown bear and the descendent of the ancient polar bear,” Dr Sykes said.

Bone chilling stories of the horrifying Yeti have been synonymous to the Himalayas for centuries with local people and some of the world’s greatest mountaineers including legendary mountaineer Reinhold Messner, who became the first man to climb Everest without oxygen, claiming to have had a terrifying encounter with a large hairy, ape-like creature.

Himalayan folk lore is rife with tales of an elusive beast that have hardly been photographed.

Professor Sykes has collected and tested hair samples of several animals found in the Himalayas.

He tested two ancient hair samples which locals of high Himalayan villages claimed were that of the Yeti. One of the samples was that of an animal found in Ladakh (India) and the other from Bhutan, 800 miles away.

The DNA tests then compared the results to other animals’ genomes stored on the GenBank database. Professor Sykes to his amazement found a 100% match with a sample from an ancient polar bear jawbone found in Svalbard, Norway, that dates back at least 40,000 years – and probably around 120,000 years.

This has made professor Sykes believe that the most likely explanation is that the Yeti is actually a hybrid between polar bears and brown bears.

A Yeti footprint on the base of Mount Everest taken by British climber Eric Shipton sparked a global interest in the abominable snowman post 1951.

List Of Ingredients To Avoid.


MDM Hydantoin and Urea: 2 preservatives that release formaldehyde which may cause joint pain, cancer, skin reactions, allergies, depression, headaches, chest pains, ear infections, chronic fatigue, dizziness and insomnia.
Sodium Lauryl Sulfate (SLS) (SLES): Used in car washes, garage floor cleaners, engine degreasers and 90% of personal-care products that foam. Eye damage, depression, labored breathing, diarrhea, skin irritation and even death.
Sunscreen chemicals: Avobenzone, benzphenone, ethoxycinnamate, PABA are commonly used ingredients that are known free radical generators and are believed to damage DNA or lead to cancers.
Triclosan: Synthetic antibacterial ingredient. EPA registers it as a pesticide, posing risks to human health and environment. Classified as a chlorophenol, chemicals suspected of causing cancer in humans.
PEG(Polyethylene glycol): Made by ethoxylating Propylene Glycol. Dangerous levels of dioxin have been found as a by-product of the ethoxylations process. PEGs are in everything including personal car, baby car and sunscreens.
Phthalates: Found in many products, usually not listed on labels. Health effects include damage to liver/ kidneys, birth defects, decreased sperm counts and early breast development is boys and girls.
Propylene Glycol(PG) and Butylene Glycol: Petroleum plastics. EPA considers PG so toxic it requires gloves, clothing, goggles and disposal by burying. EPA warns against skin contact to prevent brain, liver and kidney abnormalities.
FD&C Color and Pigments: Synthetic colors from coal tar contain heavy metal salts that deposit toxins in skin, causing skin sensitivity/irritation. Absorption can cause depletion of oxygen and death. Animals studies show almost all are carcinogenic.
Parabens (Methyl, Butyl, Ethyl, Propyl) Used as preservatives. Not always labeled. Used in deodorants and other skin care products. They have been found in breast cancer tumors. May contribute to sterility in males, hormone imbalance in females and early puberty.
Dioxin: Won’t appear in ingredients. Often in antiabacterial ingredients like triclosan, emulsifiers, PEGs and ethoxylated cleansers like sodium laureth sulfate. Dioxin causes cancer, reduced immunity, nervous system disorders, miscarriages and birth deformity.
Benzoyl Peroxide: Used in acne products, possible tumor promoter. May act as mutagen; produces DNA damage in human and other mammalian cells. Also, toxic by inhalation. Eye, skin and respiratory irritant.
DEA (Diethanolamine), MEA(Monoethanolamine) and TEA (Triethanolamine) This foam booster is a skin/ eye irritant and causes contact dermatitis . Easily absorbed through skin to accumulate in body organs and the brain.

Read more at http://www.naturalcuresnotmedicine.com/2013/10/list-of-ingredients-to-avoid.html#QFBhhEHM2IDbRHIU.99

MDM Hydantoin and Urea: 2 preservatives that release formaldehyde which may cause joint pain, cancer, skin reactions, allergies, depression, headaches, chest pains, ear infections, chronic fatigue, dizziness and insomnia.
Sodium Lauryl Sulfate (SLS) (SLES): Used in car washes, garage floor cleaners, engine degreasers and 90% of personal-care products that foam. Eye damage, depression, labored breathing, diarrhea, skin irritation and even death.
Sunscreen chemicals: Avobenzone, benzphenone, ethoxycinnamate, PABA are commonly used ingredients that are known free radical generators and are believed to damage DNA or lead to cancers.
Triclosan: Synthetic antibacterial ingredient. EPA registers it as a pesticide, posing risks to human health and environment. Classified as a chlorophenol, chemicals suspected of causing cancer in humans.
PEG(Polyethylene glycol): Made by ethoxylating Propylene Glycol. Dangerous levels of dioxin have been found as a by-product of the ethoxylations process. PEGs are in everything including personal car, baby car and sunscreens.
Phthalates: Found in many products, usually not listed on labels. Health effects include damage to liver/ kidneys, birth defects, decreased sperm counts and early breast development is boys and girls.
Propylene Glycol(PG) and Butylene Glycol: Petroleum plastics. EPA considers PG so toxic it requires gloves, clothing, goggles and disposal by burying. EPA warns against skin contact to prevent brain, liver and kidney abnormalities.
FD&C Color and Pigments: Synthetic colors from coal tar contain heavy metal salts that deposit toxins in skin, causing skin sensitivity/irritation. Absorption can cause depletion of oxygen and death. Animals studies show almost all are carcinogenic.
Parabens (Methyl, Butyl, Ethyl, Propyl) Used as preservatives. Not always labeled. Used in deodorants and other skin care products. They have been found in breast cancer tumors. May contribute to sterility in males, hormone imbalance in females and early puberty.
Dioxin: Won’t appear in ingredients. Often in antiabacterial ingredients like triclosan, emulsifiers, PEGs and ethoxylated cleansers like sodium laureth sulfate. Dioxin causes cancer, reduced immunity, nervous system disorders, miscarriages and birth deformity.
Benzoyl Peroxide: Used in acne products, possible tumor promoter. May act as mutagen; produces DNA damage in human and other mammalian cells. Also, toxic by inhalation. Eye, skin and respiratory irritant.
DEA (Diethanolamine), MEA(Monoethanolamine) and TEA (Triethanolamine) This foam booster is a skin/ eye irritant and causes contact dermatitis . Easily absorbed through skin to accumulate in body organs and the brain.

Surprising facts about carrots.


Daucus carota subsp. sativus, commonly known as the carrot, is a vegetable that is naturally healthy, sweet and delicious. These taproots are filled with a lot of compounds that are good for the health, such as antioxidants, vitamin A, minerals and beta-carotenes. These crunchy roots are a common favorite among a lot of people who love vegetables.

Carrots are cultivated all over the world for their taproots. The plant is known to be biennial in nature and starts bearing flowers once it is in its second year. Generally, however, when the taproot reaches about 1 inch in diameter, it is harvested. This is the time when the root is juicy and tender. Carrots come in different shapes and colors, depending on the types of cultivar. Oriental ones usually have flat upper ends and are long. They also have tail-like lower ends that taper off. The European counterparts come in cylindrical bodies that have rounded ends. These also come in a bright orange color compared to the saffron-colored ones from Asia.

When buying carrots, it is important to look for young ones that are bright-colored and tender. They should also be firm. Avoid buying roots that are very large, as this could indicate that they are already mature, which may make them more difficult to eat.

The Different Health Benefits

It is well-known that carrots are healthy, but what are the benefits that they give to those who eat them? Here’s a rundown of the different health benefits one could gain from eating carrots:

  • Carrots are naturally rich in vitamins, antioxidants and dietary fiber. They only give 41 calories for every 100 grams, with a negligible fat content and no cholesterol.
  • Carrots are also rich in vitamin A and beta-carotenes, which help protect people from developing mouth and lung cancers. These compounds, along with flavonoid compounds, help protect the skin too.
  • Research conducted by the scientists at the University of Newcastle discovered that falcarinol found in carrots may help prevent cancer, as it destroys cells that are pre-cancerous. The study was conducted on laboratory animals.
  • Fresh carrots are also rich in vitamin C, giving about 9% of the RDA. Vitamin C helps keep the gums, teeth and connective tissues healthy. Its antioxidant properties also help the body be protected from various diseases caused by free radicals.
  • The root is also rich in B-complex vitamins, such as vitamin B6, folic acid, thiamine and many more. These are co-factors to certain enzymes that are needed for substrate metabolism.
  • Carotenes are changed by the liver into vitamin A. This vitamin is essential for the maintenance of good vision, sperm production and skin integrity, plus normal growth and development.

Carrots are full of nutrients, which is why people should include these in their diets. These root crops can help people become healthy as well as prevent the onset of various diseases, including cancer. Young and tender carrots are the best ones, as they are sweet and full of various nutrients.

Sources for this article include:

http://myhealthbynature.com

http://www.care2.com

http://www.naturalnews.com

http://science.naturalnews.com

The fight against obesity starts in the head, not in the stomach


The Nice guidance telling GPs to be respectful to the obese is long overdue – fat-jiggling is humiliating and doesn’t work.

Having your pot belly jiggled at any age isn’t nice. The doctor (I remember your name, lady – I’ve not forgotten) who decided mine needed wobbling when I was 16 was rather misguided. No – actually she was tremendously insensitive. Her pinching of my belly fat combined with the question “when are you going to get rid of this?” sent me straight home to a packet of salt and vinegar Hula Hoops. After a horrible medical appointment, I indulged in a beautiful, fatty, carb jewellery fest that adorned every finger. I swallowed it fast in an act of fat teenage rebellion.

Doctor and overweight boy

The talking-tough approach never worked with me. Over the years various medical professionals tried different techniques to tackle my obesity. There was the slip-it-in-at-the-end-of-the-appointment ploy: “Have you considered losing a bit of weight?” Nah, bye! There was the blaming-an-unrelated-medical-condition-on-your-weight tactic, in which you would go in with a sore throat and somehow your weight becomes the issue instead. On one occasion tonsillitis turned out to be a magnificent slimming technique until I discovered 99 flake cornets were quite soothing. However the subject of my weight was tackled by doctors, their manner was often rather aggressive, with a perceptible impatience and distaste.

The new National Institute for Health and Care Excellence (Nice) guidance that doctors must treat obese patients with respect is therefore very welcome. I don’t want anyone else to go through having their fat wobbled. Nice’s realisation that programmes run by Weight Watchers and Slimming World are not a “magic bullet” is commendable too. A female relative has been alternating between both groups for more than a year because the NHS pays for it. Her weight loss from these sessions has been nil. As she says, though, it’s a “great little social club and good to get out”.

Our obesity problem has gone way beyond the remit of most GPs. As Nice has realised, the important issues in any weight-loss journey are the individual’s desire to lose weight and the reason why they are obese in the first place. In my experience this often involves deep-rooted psychological factors, which mean food is an emotional panacea. In many cases you have to address what’s going on in the person’s head long before you can tackle what is happening to their body.

Every doctor should have an individual approach for each patient. This softly, softly approach won’t work with everyone: a friend lost five stone after being told he would never see his son get married. That would have been way too harsh for many, but the medical profession is caught on the horns of a big fat problem: what will motivate others will send others straight to an entire tub of Häagen Dazs.

We have to stop seeing doctors as the solution to what happens on our scales and simply as people who can provide a range of services that we can take advantage of – and that for many has to include psychiatric intervention. For others it’s as simple as stop making excuses, eat less and move more. As adults our weight is our personal responsibility. We have to work out what we need with the help of the medical profession and not expect them to have any silver bullet – delivered in a soft or more brutal way.

What partly worked for me was a Sri Lankan gynaecologist who very gently suggested that losing some weight may help me to resume a normal menstrual cycle. He asked me what exercise I enjoyed doing – I said walking with the personal stereo in fields pretending I was in pop videos – and he told me to do it more. At 41 I still do this and it still works. My weight goes up and down – but that’s my problem. As it is yours.