May 22

Guest post.




It is no secret that the wavelengths of light that you are exposed to have an effect on your body, mind and brain. Do you know what kind of light you are being exposed to and how they are changing the way you feel, behave and think? It’s time to make yourself aware and make the changes you need to optimize yourself and your surroundings.

The light that you want in your life is natural sunlight. With all the warnings about sun exposure and skin cancer, you may be thinking that it is better to avoid the sun altogether. That’s so far from the truth that it’s scary how many people truly believe this to be the case.

There are some people who are afflicted with a disorder known as seasonal affective disorder. This is where people feel their emotions and thought patterns changing with the seasons. The truth is that the biggest part of this disorder is the changing amounts of sun that you get through the year. You find yourself happier during the sunny months of the summer and you feel depressed and awful during the winter. One of the most common tools that people use are customized LED lights designed to produce light with the same wavelength and kelvin rating as real sunlight.

The standard incandescent bulbs that you find in everyday life are a nasty yellow light that may look like what you think natural sunlight looks like, but real sunlight isn’t yellow. Real sunlight is clear and bright with a perfectly balanced ratio of the different wavelengths your brain needs to function properly.

I started installing lights in my home that replicate real sunlight because I started to grow my own hot pepper plants. I noticed that I was feeling brighter and happier during my day. I ended up comparing my CFL and LED lights to the doctor prescribed lights that my girlfriend has to help her seasonal affective disorder. They are almost identical to each other while my CFL and LED lights are a lot less expensive and can be used in standard lighting fixtures.

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Mar 09

LED’s efficiency exceeds 100% (PhysOrg.com, Mar 5, 2012):

For the first time, researchers have demonstrated that an LED can emit more optical power than the electrical power it consumes. Although scientifically intriguing, the results won’t immediately result in ultra-efficient commercial LEDs since the demonstration works only for LEDs with very low input power that produce very small amounts of light.

The researchers, Parthiban Santhanam and coauthors from MIT, have published their study in a recent issue of Physical Review Letters.

As the researchers explain in their study, the key to achieving a power conversion efficiency above 100%, i.e., “unity efficiency,” is to greatly decrease the applied voltage. According to their calculations, as the voltage is halved, the input power is decreased by a factor of 4, while the emitted light power scales linearly with voltage so that it’s also only halved. In other words, an LED’s efficiency increases as its output power decreases. (The inverse of this relationship – that LED efficiency decreases as its output power increases – is one of the biggest hurdles in designing bright, efficient LED lights.)

In their experiments, the researchers reduced the LED’s input power to just 30 picowatts and measured an output of 69 picowatts of light – an efficiency of 230%. The physical mechanisms worked the same as with any LED: when excited by the applied voltage, electrons and holes have a certain probability of generating photons. The researchers didn’t try to increase this probability, as some previous research has focused on, but instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the device’s atomic lattice, which occur due to entropy.

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Sep 04

Battered by soaring energy costs and aghast at dwindling fish stocks, Japanese scientists think they have found the answer: filling the seas with giant “eco-rigs” as powerful as nuclear power stations.

The project, which could result in village-sized platforms peppering the Japanese coastline within a decade, reflects a growing panic in the country over how it will meet its future resource needs.

The floating eco-rig generators which measure 1.2 miles by 0.5 miles (2km by 800m) are intended to harness the energy of the Sun and wind. They are each expected to produce about 300 megawatt hours of power.

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