Yes Ask So Help (YASH): YASH - How To Guides

Yes Ask So Help (YASH): YASH - How To Guides

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Yes Ask So Help (YASH): Sea surface height evidence for long-term warming ...

Yes Ask So Help (YASH): Sea surface height evidence for long-term warming ...: Tropical cyclones have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this warming effect ...

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Sea surface height evidence for long-term warming effects of tropical cyclones on the ocean

Tropical cyclones have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this warming effect is still lacking. We quantified cyclone-induced ocean warming by directly monitoring the thermal expansion of water in the wake of cyclones, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on seasonal and longer timescales. We find that the long-term effect of cyclones is to warm the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial warming, making cyclones potentially important modulators of the climate by affecting heat transport in the ocean–atmosphere system. Furthermore, our analysis reveals that the rate of warming increases with cyclone intensity. This, together with a predicted shift in the distribution of cyclones toward higher intensities as climate warms, suggests the ocean will get even warmer, possibly leading to a positive feedback.

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Microbial battery for efficient energy recovery

Significance

This work introduces a microbial battery for recovery of energy from reservoirs of organic matter, such as waste-water. By harnessing the oxidative power of microorganisms, energy can be recovered from reservoirs of less-concentrated organic matter, such as marine sediment, wastewater, and waste biomass. Left unmanaged, these reservoirs can become eutrophic dead zones and sites of greenhouse gas generation. Here, we introduce a unique means of energy recovery from these reservoirs—a microbial battery (MB) consisting of an anode colonized by microorganisms and a reoxidizable solid-state cathode. The MB has a single-chamber configuration and does not contain ion-exchange membranes. Bench-scale MB prototypes were constructed from commercially available materials using glucose or domestic wastewater as electron donor and silver oxide as a coupled solid-state oxidant electrode. The MB achieved an efficiency of electrical energy conversion of 49% based on the combustion enthalpy of the organic matter consumed or 44% based on the organic matter added. Electrochemical reoxidation of the solid-state electrode decreased net efficiency to about 30%. This net efficiency of energy recovery (unoptimized) is comparable to methane fermentation with combined heat and power.Microorganisms at an anode oxidize dissolved organic substances, releasing electrons to an external circuit, where power can be extracted. The electrons then enter a solid-state electrode that remains solid as electrons accumulate within it. The solid-state electrode is periodically removed from the battery, oxidized, and reinstalled for sustained power production. Molecular oxygen is not introduced into the battery, and ion-exchange membranes are avoided, enabling high efficiencies of energy recovery.

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STANFORD SCIENTISTS USE 'WIRED MICROBES' TO GENERATE ELECTRICITY FROM SEWAGE

Interdisciplinary team creates 'microbial battery' driven by naturally occurring bacteria that evolved to produce electricity as they digest organic material.

Engineers at Stanford University have devised a new way to generate electricity from sewage using naturally-occurring “wired microbes” as mini power plants, producing electricity as they digest plant and animal waste.

At the moment, however, their laboratory prototype is about the size of a D-cell battery and looks like a chemistry experiment, with two electrodes, one positive, the other negative, plunged into a bottle of wastewater.

One day they hope it will be used in places such as sewage treatment plants, or to break down organic pollutants in the “dead zones” of lakes and coastal waters where fertilizer runoff and other organic waste can deplete oxygen levels and suffocate marine life.

Scientists have long known of the existence of what they call exoelectrogenic microbes – organisms that evolved in airless environments and developed the ability to react with oxide minerals rather than breathe oxygen as we do to convert organic nutrients into biological fuel.

The tubular growth depicted here is a type of microbe that can produce electricity. Its wire-like tendrils are attached to a carbon filament. This image is taken with a scanning electron microscope. More than 100 of these "exoelectrogenic microbes" could fit side by side in a human hair

What is new about the microbial battery is a simple yet efficient design that puts these exoelectrogenic bacteria to work.

At the battery's negative electrode, colonies of wired microbes cling to carbon filaments that serve as efficient electrical conductors. Using a scanning electron microscope, the Stanford team captured images of these microbes attaching milky tendrils to the carbon filaments.

"You can see that the microbes make nanowires to dump off their excess electrons," Criddle said. To put the images into perspective, about 100 of these microbes could fit, side by side, in the width of a human hair.

Stanford scientists have developed a "battery" that harnesses a special type of microbe to produce electricity by digesting the plant and animal waste dissolved in sewage. Of course, there is far less energy potential in wastewater. Even so, the inventors say the microbial battery is worth pursuing because it could offset some of the electricity now use to treat waste-water. That use currently accounts for about three percent of the total electrical load in developed nations. Most of this electricity goes toward pumping air into wastewater at conventional treatment plants where ordinary bacteria use oxygen in the course of digestion, just like humans and other animals. The Stanford engineers estimate that the microbial battery can extract about 30 percent of the potential energy locked in wastewater. That is roughly the same efficiency at which the best commercially available solar cells convert sunlight into electricity.

As these microbes ingest organic matter and convert it into biological fuel, their excess electrons flow into the carbon filaments and across to the positive electrode, which is made of silver oxide, a material that attracts electrons. "We demonstrated the principle using silver oxide, but silver is too expensive for use at large scale," said Cui, an associate professor of materials science and engineering, who is also affiliated with the SLAC National Accelerator Laboratory. "Though the search is underway for a more practical material, finding a substitute will take time."

The electrons flowing to the positive node gradually reduce the silver oxide to silver, storing the spare electrons in the process. 

Looking ahead, the Stanford engineers say their biggest challenge will be finding a cheap but efficient material for the positive node.

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Yes Ask So Help (YASH): Dell launches Alienware laptops

Yes Ask So Help (YASH): Dell launches Alienware laptops: Yash Bhandari Dell launches Alienware laptops D ell’s Alienware series of gaming rigs have been a favourite amongst gamers for y...

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Yes Ask So Help (YASH): How to Craft the Perfect Blog Posts

Yes Ask So Help (YASH): How to Craft the Perfect Blog Posts: Blogging is a great way of sharing news, information and opinions for both individuals and businesses. How can you write a great post? Y...

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How Dragonflies Could Help Scientists Build Better Robots

Dragonflies process light and dark a little differently than the rest of us.

New research into the visual system of dragonflies could one day improve target detection and tracking in robotics, according to a pair of Australian researchers.

 "Most animals will use a combination of ON switches with other ON switches in the brain, or OFF and OFF, depending on the circumstances," according to Wiederman, lead author of the study in the Journal of Neuroscience. The dragonfly, in contrast, uses a combination of both ON and OFF switches to see dark objects. It's possible that other animals use this type of circuit as well, and this is just the first time scientists have discovered it.

Visual processing in most animals, both vertebrates and invertebrates, consists of two channels that process light and dark separately, called ON and OFF channels.

Steven Wiederman and David O'Carroll from the Center for Neuroscience Research at the University of Adelaide in Australia have been studying insect vision in the hopes of improving artificial vision for robotics and to develop neural prosthetics. They've found that dragonflies have an unusual visual circuit that allows them to see dark moving objects.

It allows dragonflies to respond to dark moving targets, like potential prey, much better than the researchers expected.

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