green_tech (4)

Protocells...

PSE_Artificial-Cell-Electron-Microscopy_web_1600x900.jpg
This scanning electron microscope image was taken of artificial “protocells” created at Argonne’s Center for Nanoscale Materials, which have the ability to convert light to chemical energy through the use of a light-harvesting membrane. (Image by Argonne National Laboratory.)

 

Topics: Alternative Energy, Battery, Biology, Green Tech, Nanotechnology


By replicating biological machinery with non-biological components, scientists have found ways to create artificial cells that accomplish a key biological function of converting light into chemical energy.

In a study from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, scientists created cell-like hollow capsule structures through the spontaneous self-assembly of hybrid gold-silver nanorods held together by weak interactions. By wrapping these capsules’ walls with a light-sensitive membrane protein called bacteriorhodopsin, the researchers were able to unidirectionally channel protons from the interior of the artificial cells to the external environment.

“Nature uses compartmentalization to accomplish biological functions because it brings in close vicinity the ingredients needed for chemical reactions,” said Argonne nanoscientist Elena Rozhkova, a corresponding author of the study. ​“Our goal was to replicate nature, yet use inanimate materials to probe how cells accomplish their biological tasks.”

 

Scientists harvest energy from light using bio-inspired artificial cells
Jared, Sagoff, Argonne National Laboratory

Read more…

Twisted Fridge...

Twisted-fridge.jpg
Fridge-freezer: twistocaloric cooling could be coming to a kitchen near you. (Courtesy: iStock/Allevinatis)

 

Topics: Applied Physics, Green Tech, Research, Thermodynamics


A new refrigeration technology based on the twisting and untwisting of fibers has been demonstrated by a team led by Zunfeng Liu at Nankai University in China and Ray Baughman at the University of Texas at Dallas in the US. As the demand for refrigeration expands worldwide, their work could lead to the development of new cooling systems that do not employ gases that are harmful to the environment.

The cooling system relies on the fact that some materials undergo significant changes in entropy when deformed. As far back as 1805 – when the concepts of thermodynamics were first being developed – it was known that ordinary rubber heats up when stretched and cools down when relaxed. In principle, such mechanocaloric materials could be used in place of the gases that change entropy when compressed and expanded in commercial refrigeration systems. Replacing gas-based systems is an important environmental goal because gaseous refrigerants tend to degrade the ozone layer and are powerful greenhouse gases.

In their experiments, Liu and Baughman’s team studied the cooling effects of twist and stretch changes in twisted, coiled and supercoiled fibers of natural rubber, nickel-titanium and polyethylene fishing line. In each material, they observed a surface cooling as high as 16.4 °C, 20.8 °C, and 5.1 °C respectively, which they achieved through techniques including simultaneous releases of twisting and stretching, and unraveling bundles of multiple wires.

 

Refrigerator works by twisting and untwisting fibers, Materials, Physics World

Read more…

2D MXenes...

solar-farm-662095604-iStock_Milos-Muller.jpg
Helper two-dimensional metal-carbide layers could improve perovskite solar cell stability and help make these complex solar cells a viable green energy option. Credit: iStock Milos-Muller

 

Topics: Condensed Matter Physics, Green Tech, Materials Science, Metamaterials, Nanotechnology, Solar Power


With the reality of climate change looming, the importance of realistic green energy sources is higher than ever. Solar cells are one promising avenue, as they can convert readily available visible and ultraviolet energy into usable electricity. In particular, perovskite materials sandwiched between other support layers have demonstrated impressive power conversion efficiencies. Current challenges reside in optimizing perovskite/support layer interfaces, which can directly impact power conversion and cell degradation. Researchers Antonio Agresti et al. under the direction of Aldo Di Carlo at the University of Rome Tor Vergata in Italy have investigated how cells containing two-dimensional titanium-carbide MXene support layers could improve perovskite solar cell performance.

To obtain good power conversion within a perovskite solar cell, all layers and layer interfaces within the cell must have good compatibility. Typical cells contain the active perovskite material sandwiched between two charge transport layers, which are then adjacent to their corresponding electrodes. Support layers may also be added. Charge mobility, energy barriers, interface energy alignment, and interfacial vacancies all impact compatibility and subsequent cell performance and stability. Thus, engineering well-suited interfaces with the cell is paramount to cell success and long-term stability, an important criterion for potential commercialization.

Two-dimensional buffer materials could help to modify and promote useful interface interactions. MXenes, a growing class of two-dimensional transitional metal carbides, nitrides, and carbonitrides, have shown impressive electronic properties that are easily tuned via surface modification. For example, the band gap of an MXene can be modified by changing the surface termination group from an oxygen atom to a hydroxide molecule. Additionally, MXene composition impacts the overall material performance. This type of fine-tuning allows impressive control over MXene properties and makes them ideal for interface adjustments.

 

Two-dimensional MXenes improve perovskite solar cell efficiency
Amanda Carr, Physics World

#P4TC: MXenes...August 24, 2015

Read more…

No Planet B...

ma_NF_chemistry_leadwindmill_1280x720.jpg
BENEDETTO CRISTOFANI/SALZMANART

 

Topics: Chemistry, Climate Change, Economy, Global Warming, Green Tech, Jobs


This week will be historic. In over 150 countries, people are stepping up to support young climate strikers and demand an end to the age of fossil fuels. The climate crisis won’t wait, so neither will we. Source: Global Climate Strike dot net

As with the Parkland demonstrations on mass shootings, young people are leading us - actually, PULLING us over the line to DO something about both important matters.
 
This is not about being "woke": it's about being aware. The extreme avarice causing this societal division and economic stratification could be just the petard humanity hoists itself with* to extinction. I'm glad you all know that, because old, fossilized wealthy (men mostly) can't see beyond the next quarter; that their wealth also falls to dust if the planet fails beneath them. As far as the youth, this is THEIR planet as those above septuagenarians and octogenarians are exiting it. The very least adults can do is use our ashes to fertilize trees for more oxygen (my personal plans). We should leave something for them to live out their lives and dreams. To do less is the height of arrogance, self-destruction and egomania.

Shakespeare's phrase, *"hoist with his own petard", is an idiom that means "to be harmed by one's own plan to harm someone else" or "to fall into one's own trap", implying that one could be lifted (blown) upward by one's own bomb, or in other words, be foiled by one's own plan. Source: Wikipedia
 

*****


Black, gooey, greasy oil is the starting material for more than just transportation fuel. It's also the source of dozens of petrochemicals that companies transform into versatile and valued materials for modern life: gleaming paints, tough and moldable plastics, pesticides, and detergents. Industrial processes produce something like beauty out of the ooze. By breaking the hydrocarbons in oil and natural gas into simpler compounds and then assembling those building blocks, scientists long ago learned to construct molecules of exquisite complexity.

Fossil fuels aren't just the feedstock for those reactions; they also provide the heat and pressure that drive them. As a result, industrial chemistry's use of petroleum accounts for 14% of all greenhouse gas emissions. Now, growing numbers of scientists and, more important, companies think the same final compounds could be made by harnessing renewable energy instead of digging up and rearranging hydrocarbons and spewing waste carbon dioxide (CO2) into the air. First, renewable electricity would split abundant molecules such as CO2, water, oxygen (O2), and nitrogen into reactive fragments. Then, more renewable electricity would help stitch those chemical pieces together to create the products that modern society relies on and is unlikely to give up.

Chemists in academia, at startups, and even at industrial giants are testing processes—even prototype plants—that use solar and wind energy, plus air and water, as feedstocks. "We're turning electrons into chemicals," says Nicholas Flanders, CEO of one contender, a startup called Opus 12. The company, located in a low-slung office park in Berkeley, has designed a washing machine–size device that uses electricity to convert water and CO2 from the air into fuels and other molecules, with no need for oil. At the other end of the commercial scale is Siemens, the manufacturing conglomerate based in Munich, Germany. That company is selling large-scale electrolyzers that use electricity to split water into O2 and hydrogen (H2), which can serve as a fuel or chemical feedstock. Even petroleum companies such as Shell and Chevron are looking for ways to turn renewable power into fuels.

Changing the lifeblood of industrial chemistry from fossil fuels to renewable electricity "will not happen in 1 to 2 years," says Maximilian Fleischer, chief expert in energy technology at Siemens. Renewable energy is still too scarce and intermittent for now. However, he adds, "It's a general trend that is accepted by everybody" in the chemical industry.

I repeat:
1437790_1.jpg
Tee Public: I'm going to buy this shirt

 

Can the world make the chemicals it needs without oil?
Robert F. Service, Science Magazine

Read more…