Lindsey

-Engineering Student

-GIS Analyst
- Always working/No vacation

trigonometry-is-my-bitch:

Scientists at MIT manage to make steam directly from the sun - Could develop into new, more efficient way of generating electricity in conventional power generators.

A new material structure developed at MIT generates steam by soaking up the sun.

The structure — a layer of graphite flakes and an underlying carbon foam — is a porous, insulating material structure that floats on water. When sunlight hits the structure’s surface, it creates a hotspot in the graphite, drawing water up through the material’s pores, where it evaporates as steam. The brighter the light, the more steam is generated.

The new material is able to convert 85% of incoming solar energy into steam — a significant improvement over recent approaches to solar-powered steam generation. What’s more, the setup loses very little heat in the process, and can produce steam at relatively low solar intensity. This would mean that, if scaled up, the setup would likely not require complex, costly systems to highly concentrate sunlight.

Hadi Ghasemi, a postdoc in MIT’s Department of Mechanical Engineering, says the spongelike structure can be made from relatively inexpensive materials — a particular advantage for a variety of compact, steam-powered applications.

“Steam is important for desalination, hygiene systems, and sterilization,” says Ghasemi, who led the development of the structure. “Especially in remote areas where the sun is the only source of energy, if you can generate steam with solar energy, it would be very useful.”

Ghasemi and mechanical engineering department head Gang Chen, along with five others at MIT, report on the details of the new steam-generating structure in the journal Nature Communications. 

Cutting the optical concentration

Today, solar-powered steam generation involves vast fields of mirrors or lenses that concentrate incoming sunlight, heating large volumes of liquid to high enough temperatures to produce steam. However, these complex systems can experience significant heat loss, leading to inefficient steam generation.

Recently, scientists have explored ways to improve the efficiency of solar-thermal harvesting by developing new solar receivers and by working with nanofluids. The latter approach involves mixing water with nanoparticles that heat up quickly when exposed to sunlight, vaporizing the surrounding water molecules as steam. But initiating this reaction requires very intense solar energy — about 1,000 times that of an average sunny day.

By contrast, the MIT approach generates steam at a solar intensity about 10 times that of a sunny day — the lowest optical concentration reported thus far. The implication, the researchers say, is that steam-generating applications can function with lower sunlight concentration and less-expensive tracking systems.  

“This is a huge advantage in cost-reduction,” Ghasemi says. “That’s exciting for us because we’ve come up with a new approach to solar steam generation.”

From sun to steam

The approach itself is relatively simple: Since steam is generated at the surface of a liquid, Ghasemi looked for a material that could both efficiently absorb sunlight and generate steam at a liquid’s surface.

After trials with multiple materials, he settled on a thin, double-layered, disc-shaped structure. Its top layer is made from graphite that the researchers exfoliated by placing the material in a microwave. The effect, Chen says, is “just like popcorn”: The graphite bubbles up, forming a nest of flakes. The result is a highly porous material that can better absorb and retain solar energy.

The structure’s bottom layer is a carbon foam that contains pockets of air to keep the foam afloat and act as an insulator, preventing heat from escaping to the underlying liquid. The foam also contains very small pores that allow water to creep up through the structure via capillary action.

As sunlight hits the structure, it creates a hotspot in the graphite layer, generating a pressure gradient that draws water up through the carbon foam. As water seeps into the graphite layer, the heat concentrated in the graphite turns the water into steam. The structure works much like a sponge that, when placed in water on a hot, sunny day, can continuously absorb and evaporate liquid.

The researchers tested the structure by placing it in a chamber of water and exposing it to a solar simulator — a light source that simulates various intensities of solar radiation. They found they were able to convert 85% of solar energy into steam at a solar intensity 10 times that of a typical sunny day.

Ghasemi says the structure may be designed to be even more efficient, depending on the type of materials used.

“There can be different combinations of materials that can be used in these two layers that can lead to higher efficiencies at lower concentrations,” Ghasemi says. “There is still a lot of research that can be done on implementing this in larger systems.”

source - MIT news

(via the-jamjam)

zerostatereflex:

Squishy Robots

"A new phase-changing material built from wax and foam developed by researchers at MIT is capable of switching between hard and soft states."

MIT researchers are trying to change the paradigm of your typical robot by mimicking organic substances. The idea is that the robot should be soft to conform to a particular environment, and interact with humans, though rigid enough to actually do a procedure. They can achieve this by applying heat at particular points to deform the object, then applying coolness to make the object rigid again. 

"Robots built from this material would be able to operate more like biological systems with applications ranging from difficult search and rescue operations, squeezing through rubble looking for survivors, to deformable surgical robots that could move through the body to reach a particular point without damaging any of the organs or vessels along the way."

The last gif is a example of bendable articulation. :D 

(via the-jamjam)

Beware of the man who works hard to learn something, learns it, and finds himself no wiser than before. He is full of murderous resentment of people who are ignorant without having come by their ignorance the hard way.
Kurt Vonnegut, Cat’s Cradle (via quotes-shape-us)

MY LOVE. COME TO ME LOVE!

(via tinkerxbellx)

feminismisforlosers:

karathraceandherspecialdestiny:

even she’s not down with gender norms and refuses to shave her armpits and legs since boys don’t have to.

That’s actually really disgusting, like what the fuck. You’re a horrible big sister if you don’t teach her that she’s being fucking gross.

Are you serious right now? She’s a 12 year little girl that doesn’t even need to start shaving yet. Calm the fuck down you internet troll and get off my shit. MY LITTLE SISTER AND ANY LITTLE GIRL CAN DO WHATEVER THE FUCK THEY CHOOSE TO. So if that’s not shaving her legs or she decides to do something that society doesn’t deem correct for girls then more power to her. Anybody is allowed to be who they choose to, and you are just a part of the never ending problem of body shaming and little girls that grow up with image problems.

(via feminismisforlosers-deactivated)

Sunburnt after a day full of rides and wake skating at Wet N Wild.

It’s been dead for more than a year and I put up some older photos.Check it out. I’m going to start shooting again, so I should update it more frequently, (no promises though) follow it. PHOTO BLOG HERE

fotojournalismus:

Airstrikes in Gaza | July 2014

1. An Israeli activist carries a placard during a protest against the war on the Gaza strip, in the Israeli city of Tel Aviv on July 9, 2014. (Ahmad Gharabli/AFP/Getty Images)

2. Smoke and flames are seen following an Israeli air strike in Rafah in the southern Gaza Strip on July 9, 2014. (Reuters)

3. Palestinian relatives mourn during the funeral of members of Hamad family in the town of Beit Hanoun in the northern Gaza Strip on July 9, 2014. (Mohammed Salem/Reuters)

4. Palestinians inspect the remains of a car which was hit in an Israeli air strike in Gaza City on July 9, 2014. (Ashraf Amrah/Reuters)

5. Relatives of eight Palestinian members from al-Haj family, who medics said were killed in an early morning air strike that destroyed at least two homes, mourn during their funeral in Khan Younis in the southern Gaza Strip on July 10, 2014. (Ibraheem Abu Mustafa/Reuters)

6. A picture taken in Gaza City on July 10, 2014 shows a damaged building after it was hit by an Israeli air strike. (Mohammed Abed/AFP/Getty Images)

7. A Palestinian woman runs carrying a girl following an Israeli air strike on a house in Gaza city on July 9, 2014. (Majdi Fathi/Reuters)

8. Two boys stand near damage caused by Israeli warplanes in Gaza on July 10, 2014. (Yasser Qudih/NurPhoto/Corbis)

9. Israelis watch as smoke rises after air strikes across the border in northern Gaza on July 8, 2014. (Amir Cohen/Reuters)

10. A Palestinian boy plays in the rubble of a destroyed house the day after an Israeli strike in the town of Beit Hanoun, northern Gaza Strip on July 9, 2014. (Khalil Hamra/AP)

(Sources: 1, 2, 3, 4, 5, 6, 7, 8, 9)

(via jillianmaris)