Researchers have uncovered the complex interdependence and orchestration of metabolic reactions, gene regulation, and environmental cues of clostridial metabolism. Ting Lu, an assistant professor of bioengineering at the University of Illinois at Urbana-Champaign led the team in providing new insights for advanced biofuel development.

Lu explained, “This work advances our fundamental understanding of the complex, system-level process of clostridial acetone-butanol-ethanol (ABE) fermentation. Simultaneously, it provides a powerful tool for guiding strain design and protocol optimization, therefore facilitating the development of next-generation biofuels.”

Clostridium Acetobutylicum.  Image Credit: Public Domain from Wikipedia.

Clostridium Acetobutylicum. Image Credit: Public Domain from Wikipedia.

Microbial metabolism is a means by which a microbe uses nutrients and generates energy to live and reproduce. It typically involves complex biochemical processes implemented through the orchestration of metabolic reactions and gene regulation, as well as their interactions with environmental cues. One canonical example is the ABE fermentation by Clostridium acetobutylicum, during which cells convert carbon sources to organic acids that are later re-assimilated to produce solvents as a strategy for cellular survival.

Lu, who is also affiliated with the Department of Physics and Carl R. Woese Institute for Genomic Biology at Illinois set ups the background with, “Clostridium is very much like a factory during fermentation which converts carbon sources into renewable, advanced biofuels that can be directly used to fuel your car. The complexity and systems nature of the process have been largely underappreciated, rendering challenges in understanding and optimizing solvent (ABE) production.”

Chen Liao, a bioengineering graduate student and first author of their study paper said, “In this study, we developed an integrated computational framework for the analysis and exploitation of the solvent metabolism by C. acetobutylicum.”

The paper, “Integrated, Systems Metabolic Picture of Acetone-Butanol-Ethanol Fermentation by Clostridium acetobutylicum,” has been published in the Proceedings of the National Academy of Sciences of the United States of America.

Lu sums the work up, “To our knowledge, this framework elucidates, for the first time, the complex system-level orchestration of metabolic reactions, gene regulation, and environmental cues during clostridial ABE fermentation. It also provides a quantitative tool for generating new hypotheses and for guiding strain design and protocol optimization – invaluable for the development of efficient metabolic engineering strategies, expediting the development of advanced biofuels. More broadly, by using the ABE fermentation as an example, the work further sheds light on systems biology toward an integrated and quantitative understanding of complex microbial physiology.”

Lu sums up academically. In other more mainstream words the team has reached a milestone in bacteria research by providing an activity map that one can expect will have a huge impact over time in producing much more acetone, butanol and ethanol.

For now most ethanol is produced using processes that convert the plant starches to sugars that are then fed to yeasts rather than bacteria. Clostridium acetobutylicum is attractive because of the production split of 3 parts acetone to 6 parts butanol and only one of ethanol. The bacterial process also begins using the plant starches skipping an entire step of converting to sugars.

Research progress is already underway with some modified bacteria showing promise. The Illinois team has reached a milestone providing gene designers a new tool to accelerate the development of better bacteria for commercial applications and likely a much increased supply of renewable fuels that are much closer to “drop in gasoline” replacements.

Massachusetts Institute of Technology researchers propose that an advanced manufacturing approach for lithium-ion batteries promises to significantly slash the cost of the most widely used type of rechargeable batteries while also improving their performance and making them easier to recycle.

Researchers at MIT and at a spinoff company called 24M with a pilot manufacturing plant setup, promise to significantly slash the cost of the most widely used type of rechargeable batteries.

Semisolid Lithium Ion Battery Pilot Production Line.  A pilot manufacturing plant at 24M's headquarters in Cambridge has produced thousands of test batteries to demonstrate the efficiency of the new design. Image Credit: 24M.  Click image for the largest view.

Semisolid Lithium Ion Battery Pilot Production Line. A pilot manufacturing plant at 24M’s headquarters in Cambridge has produced thousands of test batteries to demonstrate the efficiency of the new design.
Image Credit: 24M. Click image for the largest view.

Yet-Ming Chiang, the Kyocera Professor of Ceramics at MIT and a co-founder of 24M who was also a co-founder of the battery company A123 said, “We’ve reinvented the process.”

This group is likely on to something.

Chiang explained the existing process for manufacturing lithium-ion batteries has hardly changed in the two decades since the technology was invented, and is inefficient, with more steps and components than are really needed.

The new process is based on a concept developed five years ago by Chiang and colleagues including W. Craig Carter, the POSCO Professor of Materials Science and Engineering. The concept is the so-called “flow battery,” where the electrodes are suspensions of tiny particles carried by a liquid and pumped through various compartments of the battery.

The new battery design is a hybrid between flow batteries and conventional solid ones. In this version, while the electrode material does not flow, it is composed of a similar semisolid, colloidal suspension of particles.  Chiang and Carter refer to this as a “semisolid battery.” This approach greatly simplifies manufacturing, and also makes batteries that are flexible and resistant to damage.

Chiang is senior author of the study paper published in the Journal of Power Sources. The paper also analyzes the tradeoffs involved in choosing between solid and flow-type batteries, depending on their particular applications and chemical components.

The analysis demonstrates that while a flow-battery system is appropriate for battery chemistries with a low energy density (those that can only store a limited amount of energy for a given weight), for high-energy-density devices such as lithium-ion batteries, the extra complexity and components of a flow system would add unnecessary extra cost.

Chiang noted that almost immediately after publishing the earlier research on the flow battery, “We realized that a better way to make use of this flowable electrode technology was to reinvent the [lithium ion] manufacturing process.”

Instead of the standard method of applying liquid coatings to a roll of backing material, and then having to wait for that material to dry before it can move to the next manufacturing step, the new process keeps the electrode material in a liquid state and requires no drying stage at all. Using fewer, thicker electrodes, the system reduces the conventional battery architecture’s number of distinct layers, as well as the amount of nonfunctional material in the structure, by 80 percent.

Having the electrode in the form of tiny suspended particles instead of consolidated slabs greatly reduces the path length for charged particles as they move through the material – a property known as “tortuosity.” A less tortuous path makes it possible to use thicker electrodes, which, in turn, simplifies production and lowers cost.

Chiang explained that in addition to streamlining manufacturing enough to cut battery costs by half, the new system produces a battery that is more flexible and resilient. While conventional lithium-ion batteries are composed of brittle electrodes that can crack under stress, the new formulation produces battery cells that can be bent, folded or even penetrated by bullets without failing. This should improve both safety and durability, he said.

The company has so far made about 10,000 batteries on its prototype assembly lines, most of which are undergoing testing by three industrial partners, including an oil company in Thailand and Japanese heavy-equipment manufacturer IHI Corp. The process has received eight patents and has 75 additional patents under review; 24M has raised $50 million in financing from venture capital firms and a U.S. Department of Energy grant.

The company is initially focusing on grid-scale installations, used to help smooth out power loads and provide backup for renewable energy sources that produce intermittent output, such as wind and solar power. But Chiang said the technology is also well suited to applications where weight and volume are limited, such as in electric vehicles.

Chiang also added another advantage of this approach that factories using the method can be scaled up by simply adding identical units. With traditional lithium-ion production, plants must be built at large scale from the beginning in order to keep down unit costs, so they require much larger initial capital expenditures. By 2020, Chiang estimates that 24M will be able to produce batteries for less than $100 per kilowatt-hour of capacity.

The third party view comes from Venkat Viswanathan, an assistant professor of mechanical engineering at Carnegie Mellon University who was not involved in this work. Viswanathan said the analysis presented in the new paper “addresses a very important question of when is it better to build a flow battery versus a static model . . . This paper will serve as a key tool for making design choices and go-no go decisions.”

Viswanathan added that 24M’s new battery design “could do the same sort of disruption to [lithium ion] batteries manufacturing as what mini-mills did to the integrated steel mills.”

Working with Chiang, the Power Sources paper was co-authored by graduate student Brandon Hopkins, mechanical engineering professor Alexander Slocum, and Kyle Smith of the University of Illinois at Urbana-Champaign.

It looks like this technology has legs and they are already walking into the market place. Congratulations are in order. Maybe they’ll make one someday that keeps my smart phone alive for a full day.

University of Wisconsin-Madison engineers and a collaborator from China have developed a nanogenerator that harvests energy from a car tire’s rolling friction. Xudong Wang, the Harvey D. Spangler fellow and an associate professor of materials science and engineering at UW-Madison, and his PhD student Yanchao Mao have been working on this device for about a year.

Nanogenerators Mounted to Toy Car Tires.  Click image for the largest view. More info in the study paper and abstract.  Image Credit: University of Wisconsin-Madison.

Nanogenerators Mounted to Toy Car Tires. Click image for the largest view. More info in the study paper and abstract. Image Credit: University of Wisconsin-Madison.

Its an innovative method of reusing energy. The nanogenerator ultimately could provide automobile manufacturers a new way to squeeze greater efficiency out of their vehicles. Wang said the nanogenerator provides an excellent way to take advantage of energy that is usually lost due to friction.

The researcher team reported their development in a paper published in the journal Nano Energy.

The nanogenerator relies on an electrode integrated into a segment of the tire. When this part of the tire surface comes into contact with the ground, the friction between those two surfaces ultimately produces an electrical charge – a type of contact electrification known as the triboelectric effect.

During initial trials, Wang and his colleagues used a toy car with LED lights to demonstrate the concept. They attached an electrode to the wheels of the car, and as it rolled across the ground, the LED lights flashed on and off. The movement of electrons caused by friction was able to generate enough energy to power the lights, supporting the idea that energy lost to friction can actually be collected and reused.

Wang explained, “The friction between the tire and the ground consumes about 10 percent of a vehicle’s fuel. That energy is wasted. So if we can convert that energy, it could give us very good improvement in fuel efficiency.”

The nanogenerator uses the triboelectric effect to harness energy from the changing electric potential between the pavement and a vehicle’s wheels. The triboelectric effect is the electric charge that results from the contact or rubbing together of two dissimilar objects.

During initial trials, Wang and his colleagues used a toy car with LED lights to demonstrate the concept. They attached an electrode to the wheels of the car, and as it rolled across the ground, the LED lights flashed on and off. The movement of electrons caused by friction was able to generate enough energy to power the lights, supporting the idea that energy lost to friction can actually be collected and reused.

“Regardless of the energy being wasted, we can reclaim it, and this makes things more efficient,” Wang said. “I think that’s the most exciting part of this, and is something I’m always looking for: how to save the energy from consumption.”

The researchers also determined that the amount of energy harnessed is directly related to the weight of a car, as well as its speed. Therefore the amount of energy saved can vary depending on the vehicle. But Wang estimates about a 10 percent increase in the average vehicle’s gas mileage given 50 percent friction energy conversion efficiency.

“There’s big potential with this type of energy,” Wang said. “I think the impact could be huge.”

Huge indeed. A few moments thought on all the friction in the developed world is quite an exercise. But lets hope that the team realizes that as much as the energy recapture and reuse has a powerful appeal, the technological application has to be simple and cheap for mass utilization.

University of Cambridge researchers have devised a new material that mimics the wing structure of owls which could help make wind turbines, computer fans and even planes much quieter. Early wind tunnel tests of the coating have shown a substantial reduction in noise without any noticeable effect on aerodynamics.

Owl, by Mirko Zammarchi via Creative Commons. Click image for the largest view.

Owl, by Mirko Zammarchi via Creative Commons. Click image for the largest view.

Because wind turbines are heavily braked in order to minimize noise, the addition of this new surface would mean that they could be run at much higher speeds producing more energy while making less noise. For an average-sized wind farm, this should mean several additional megawatts worth of electricity.

An investigation into how owls fly and hunt in silence has enabled researchers to develop a prototype coating for wind turbine blades that could significantly reduce the amount of noise they make.

The surface has been developed by researchers at the University of Cambridge, in collaboration with researchers at three institutions in the U.S. Their results were presented Monday June 22 at the American Institute of Aeronautics and Astronautics (AIAA) Aeroacoustics Conference in Dallas.

Professor Nigel Peake of Cambridge’s Department of Applied Mathematics and Theoretical Physics, who led the research said, “Many owls – primarily large owls like barn owls or great gray owls – can hunt by stealth, swooping down and capturing their prey undetected. While we’ve known this for centuries, what hasn’t been known is how or why owls are able to fly in silence.”

Peake and his collaborators at Virginia Tech, Lehigh and Florida Atlantic Universities used high resolution microscopy to examine owl feathers in fine detail. They observed that the flight feathers on an owl’s wing have a downy covering, which resembles a forest canopy when viewed from above. In addition to this fluffy canopy, owl wings also have a flexible comb of evenly-spaced bristles along their leading edge, and a porous and elastic fringe on the trailing edge.

Close-up view of a flight feather of a Great Grey Owl. Image Credit: J. Jaworski.  Click image for the largest view.

Close-up view of a flight feather of a Great Grey Owl. Image Credit: J. Jaworski. Click image for the largest view.

“No other bird has this sort of intricate wing structure,” said Peake. “Much of the noise caused by a wing – whether it’s attached to a bird, a plane or a fan – originates at the trailing edge where the air passing over the wing surface is turbulent. The structure of an owl’s wing serves to reduce noise by smoothing the passage of air as it passes over the wing — scattering the sound so their prey can’t hear them coming.”

In order to replicate the structure, the researchers looked to design a covering that would ‘scatter’ the sound generated by a turbine blade in the same way. Early experiments included covering a blade with material similar to that used for wedding veils, which despite its open structure, reduced the roughness of the underlying surface, lowering surface noise by as much as 30dB.

Although the ‘wedding veil’ worked remarkably well, it wouldn’t suitable to apply to a wind turbine or airplane. Using a similar design, the researchers then developed a prototype material made of 3D-printed plastic and tested it on a full-sized segment of a wind turbine blade. In wind tunnel tests, the treatment reduced the noise generated by a wind turbine blade by 10dB, without any appreciable impact on aerodynamics.

While the coating still needs to be optimized, and incorporating it onto an airplane would be far more complicated than a wind turbine, it could be used on a range of different types of wings and blades. The next step is to test the coating on a functioning wind turbine.

According to the researchers, a significant reduction in the noise generated by a wind turbine could allow them to be spun faster without any additional noise, which for an average-sized wind farm, could mean several additional megawatts worth of electricity.

There are a lot of wind turbines up worldwide. So saving on the wasteful speed brakes would not only add energy to the output, one would expect a savings in maintenance and other costs. What might make a huge difference is a coating that can be retrofitted.

Lots of potential here. Lets hope the wind turbine industry helps this along.

A Boston College team of researchers has achieved the first ‘unassisted’ solar water splitting using the abundant rust-like mineral hematite and silicon to capture and store solar energy into hydrogen gas. So far finding an efficient solar water splitting method to mine electron-rich hydrogen for clean power has been thwarted by the poor performance of hematite.

Boston College led team uses hematite and silicon (left) to capture and store solar energy into hydrogen gas.  Click image for the largest view.

Boston College led team uses hematite and silicon (left) to capture and store solar energy into hydrogen gas. Click image for the largest view.

The team of researchers led by chemist Dunwei Wang found by ‘re-growing’ the mineral’s surface, a smoother version of hematite doubled electrical yield, opening a new door to energy-harvesting artificial photosynthesis.

The team’s report has been published online in the journal Nature Communications.

Re-grown hematite proved to be a better power generating anode, producing a record low turn-on voltage that enabled the researchers to be the first to use earth-abundant hematite and silicon as the sole light absorbers in artificial photosynthesis, said Boston College associate professor of chemistry Dunwei Wang, a lead author of the report.

The new hydrogen harvesting process achieved an overall efficiency of 0.91 percent, a ‘modest’ mark in and of itself, but the first ‘meaningful efficiency ever measured by hematite and amorphous silicon, two of the most abundant elements on Earth,’ the team reported.

“By simply smoothing the surface characteristics of hematite, this close cousin of rust can be improved to couple with silicon, which is derived from sand, to achieve complete water splitting for solar hydrogen generation,” said Wang, whose research focuses on discovering new methods to generate clean energy. “This unassisted water splitting, which is very rare, does not require expensive or scarce resources.”

Wang said the findings represent an important step toward realizing the potential performance theoretical models have predicted for hematite, an iron oxide similar to rust.

‘This offers new hope that efficient and inexpensive solar fuel production by readily available natural resources is within reach,” said Wang. “Getting there will contribute to a sustainable future powered by renewable energy.”

The team, which included researchers from Boston College, UC Berkeley and China’s University of Science and Technology, decided to focus on hematite’s surface imperfections, which have been found in earlier studies to limit ‘turn-on’ voltage required to jump-start photoelectrochemistry, the central process behind using artificial photosynthesis to capture and store solar energy in hydrogen gas.

The team re-evaluated hematite surface features using a synchrotron particle accelerator at the Lawrence Berkeley National Laboratory. They established a new ‘re-growth’ strategy that applied an acidic solution to the material under intense heat, a process that simultaneously reduced ridges and filled depressions, smoothing the surface.

Tests immediately showed an improvement in turn-on voltage, as well as an increase in photovoltage from 0.24 volts to 0.80 volts, a dramatic increase in power generation.

The team reported that further modifications to the new hematite-silicon method make it amenable to large-scale utilization. Furthermore, the ‘re-growth’ technique may be applicable to other materials under study for additional breakthroughs in artificial photosynthesis.

Wang said, “It is a delight to see that a simple re-growth treatment can do so much to improve the performance of hematite. Due to its prior poor performance, hematite has been pronounced ‘dead’ by many leading researchers in the field. We are happy to show that much can be harvested from this earth abundant, non-toxic material.”

This is an important development. While not astonishing in its efficiency, the fact of the successful existence is a major encouragement. You can be sure there will be more effort in efficiency gains and systems development. Beyond capital investment this is as close as anyone has gotten to free fuel, and it isn’t looking wildly expensive.


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