From Pig to Fuel - Anaerobic digester generates energy, reduces odors

 Teng Lim is operating a small-scale anaerobic digester at the MU swine farm in Columbia. The system generates energy and can mitigate hog odor. Courtesy Jon Lamb.

The University of Missouri has unveiled a prototype small-scale anaerobic digestion system that produces biogas from pig manure. The biogas can be used to heat a farm and create electricity. The device also reduces odor from swine operations.

“What we want to do is improve and fully utilize all the biogas for energy production,” said Teng Lim, Extension Ag Systems Management associate professor.

Funded by the MU College of Agriculture, Food and Natural Resources, the anaerobic digester consists of three tanks. Manure from the hog barn pit is pumped into one tank where the manure is stored and mixed. The anaerobic digestion takes place in the other two tanks, where bacteria break down the manure in these warm and oxygen-free tanks.

The biogas from the manure can be used for electricity and hot water production. With some further treatment it can also be stored as a compressed natural gas, for heating or even vehicle fuel.

PigsLim says a larger scale digester could supply a farm’s energy needs and also be sold to the grid to provide electricity to the community.

There are other benefits to anaerobic digestion in addition to energy generation. The digested manure retains the nutrients to be good fertilizer while becoming a more consistent product. Also, the digester can reduce odor emissions.

“When the manure is treated by the digester process the odor concentration is significantly reduced,” Lim said. “There is still going to be odor, but it’s going to be much lower and less fluctuation than the raw manure.”

A Lot of Pork

The swine industry is big in the United States – there are 73,150 pork farms in America with 120 million pigs marketed each year.

Before the 1960s, most pork in the U.S. was raised in outside lots or on pasture systems. With the development of slotted floors and liquid manure handling equipment, it became possible for producers to more easily care for larger numbers of animals. Enclosed buildings overcame most weather problems and predators, and minimized the potential pollution from outside lot runoff.

Typically, pig odor is a localized air quality problem, with low concentrations of odorous gases such as p-cresol. Odor problems are often a starting point for litigation. Many farmers can go out of business just fighting a lawsuit.

An Important Part of Future Farms?

There are challenges to anaerobic digestion, the biggest being cost and management. In a commercial setting the digester would be 100 times larger than the one at MU’s swine research facility.

Lim pointed out that industry leaders and scientists believe anaerobic digesters will be an important piece of future farms, both to mitigate odor and for generating renewable energy.  The cost is a major obstacle now. The team is working closely with industry experts from Martin Machinery, a Missouri company who specializes in biogas generators and control systems.

MU researchers are using the scaled down digester to find ways to make digesters more affordable and easier to manage. They are also using it as an education tool to show producers the potentials, what it takes to process the manure, and to train people how to properly run a system like this.

Source: Cafnr

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Grad Student Solves 30-Year-Old Physics Problem

                    Emilie Huffman, second year PhD student in physics. Credit: Duke University

Sometimes an age-old question just needs a fresh set of eyes.

That was the case in Duke’s physics department, where a graduate student and professor recently resolved a calculating dilemma that has vexed computational physicists for decades.

Emilie Huffman is a second-year PhD student from Charlotte, North Carolina. Last spring she began working with Shailesh Chandrasekharan, an associate professor and the director of graduate studies in physics, on what’s known as a sign problem.

Chandrasekharan is a theoretical nuclear and particle physicist who specializes in solving sign problems, which arise when one uses certain computational algorithms to calculate the behavior of large numbers of particles called fermions.

“Almost all the matter we know of are made with fermions,” Chandrasekharan said. “As building blocks of matter, it’s very important to be able to do calculations with them.”

But calculations of such complexity get tricky, and sign problems make it easy for wrong results to surface.

“It’s a very broad problem that affects almost all fields of physics involving quantum mechanics with strong correlations, where Monte Carlo methods are essential to perform calculations,” Chandrasekharan said.

Some in the field have simply moved on since the 1980s, leaving interesting questions plagued by sign problems unexplored. Other scientists have found workarounds and approximations. Very few, including Chandrasekharan, have tried to figure out solutions through the years. Huffman began work to expand on one of her advisor’s solutions, involving a grouping concept called fermion bags, and apply them to a new class of problems.

“She finally figured out a nice formula,” Chandrasekharan said. “Although the formula is quite simple and elegant, I couldn’t guess it.”

“In physics, often there’s a truth, and if you’re hitting on the right truth, everything starts falling into place.” Chandrasekharan says that’s what happened when he began applying Huffman’s formula to a class of problems.

Their paper appeared recently in the journal Physical Review B’s Rapid Communications.

“Now that I have a solution, I can begin to apply it,” Huffman said. Starting with condensed matter physics, Huffman plans to apply her solution to various questions that have been stymied by sign problems. “I can use this solution to study properties of graphene,” she said, referring to the single-layer carbon that has been touted as the strongest material in the world. Many puzzles remain in the field, especially involving multi-layer graphene sheets.

Wherever she turns her attention next, it’s clear Huffman has a promising career ahead.

Citation: “Solution to sign problems in half-filled spin-polarized electronic systems,” Emilie Huffman and Shailesh Chandrasekharan. Physical Review B Rapid Communications, March 12, 2014. DOI: 10.1103/PhysRevB.89.111101.

Source: Duke University

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Studying patterns in bacterial organization

credit to Gerard Wong, of the California NanoSystems Institute

Bacterial biofilms, at first glance, may seem to be spontaneous, random phenomena from which we have no power to protect our environment or ourselves.

They’re potentially useful as an aid to wastewater treatment, but they also cause infections that account for $6 billion a year in health care costs. Biofilms are also more resistant to antibiotic drugs, making them difficult to eradicate.

Dr. Kun Zhao, of the California NanoSystems Institute at UCLA, refuses to see biofilms as arbitrary: he emphasizes the fact that biofilms are communities of bacteria in self-produced polymeric matrices of polysaccharides, and using a biophysical approach, he studies the pattern behind their organization.

Central questions in Zhao’s research include how bacterial colonies transition from reversible to irreversible attachment, how they migrate, and how they ultimately disperse. Specifically, Zhao examines the polysaccharide Psl, which poses a positive feedback loop because it is both secreted by moving bacteria and serves as a chemo-attractant for future bacteria movement. The positive feedback creates an inherent pattern, as bacteria are more likely to visit a location they have been to before.

Zhao and colleagues have also discovered that bacterial mutants that cannot produce Psl exhibit more random and uniform movement.

To better quantify bacterial movement,Zhao has created a computer algorithm that shows the full movement history of each individual bacterium on a dish, and that provides a “search engine” allowing researchers to find every bacterium performing specific life cycle activities, like division.

Zhao has postulated a “rich get richer” mechanism for biofilms. He compares bacterial organization to Wall Street because concentrated movement ensures that some cells become extremely enriched. In the future, he hopes to model colloidal structures for biological problems, like the growth of the bacterial cell wall. Zhao currently uses colloids, which in physics are used as models for atomic systems, to observe how shapes affect self-assembly. He also would like to look at cell-substrate interactions, which are implicated in bacterial territoriality and social interactions.

by Olivia Zhu

Source: Duke University

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Together, humans and computers can figure out plant world

A Web-based system was built for palynologists to interact with stored data and search for pollen images. This screen shows search capabilities by morphology semantics. From Han et al., part of the special issue 'Bioinformatic and Biometric Methods in Plant Morphology' in Applications in Plant Sciences. Credit: Image credit Han et al. Han, J. G., H. Cao, A. Barb, S. W. Punyasena, C. Jaramillo, and C.-R. Shyu. 2014. A neotropical Miocene pollen database employing image-based search and semantic modeling. Applications in Plant Sciences 2(8): 1400030. doi:10.3732/apps.1400030.

As technology advances, science has become increasingly about data -- how to gather it, organize it, and analyze it. The creation of key databases to analyze and share data lies at the heart of bioinformatics, or the collection, classification, storage, and analysis of biochemical and biological information using computers and software. The tools and methods used in bioinformatics have been instrumental in the development of fields such as molecular genetics and genomics. But, in the plant sciences, bioinformatics and biometrics are employed in all fields -- not just genomics -- to enable researchers to grapple with the rich and varied data sources at their disposal.

In July 2013, Surangi Punyasena of the University of Illinois at Urbana-Champaign and Selena Smith of the University of Michigan organized a special session at Botany 2013, the annual meeting of the Botanical Society of America in New Orleans, Louisiana. They invited plant morphologists, systematists, and paleobotanists, as well as computer scientists, applied mathematicians, and informaticians -- all of whom were united in their interest in developing or applying novel biometric or bioinformatic methods to the form and function of plants. The goal: to provide a forum for a cross-disciplinary exchange of ideas and methods on the theme of the quantitative analysis of plant morphology.

As Punyasena explains, "The quantitative analysis of morphology is the next frontier of bioinformatics. Humans are very good at learning to recognize shape and texture, but there are many problems where accuracy and consistency are difficult to achieve with only expert-derived, qualitative data, and in many fields there are often a limited number of experts trained in these visual assessments."

The results of that session, along with invited papers, are published in the August issue of Applications in Plant Sciences as a special issue on Bioinformatic and Biometric Methods in Plant Morphology. Morphology is, of course, the study of form, and form as represented in this collection of articles has a broad scope -- from microscopic pollen grains and charcoal particles, to macroscopic leaves and whole root systems. The methods presented in the issue, both recent and emerging, are varied as well, including automated classification and identification, geometric morphometrics, and skeleton networks, as well as tests of the limits of human assessment.

Three articles in the issue look at the application of biometric and bioinformatic methods in palynology: Han et al. (2014) introduce an online Miocene pollen database with semantic image search capabilities; Holt and Bebbington (2014) test the applications of an automated pollen classifier; and Mander et al. (2014) analyze differences in human and automated classification of grass pollen based on surface textures. Other papers highlight how biometric and bioinformatic methods apply to plants more broadly, including using skeleton networks to examine plant morphology such as roots (Bucksch, 2014), improving the quantification of geometric leaf shape metrics with a new protocol to measure leaf circularity (Krieger, 2014), comparing human and automated methods of quantifying aspects of leaf venation (Green et al., 2014), and applying morphometrics to charcoalified plant remains (Crawford and Belcher, 2014).

Taken as a whole, the issue presents a compelling argument for the importance of both computational and morphometric approaches.

"I think that there's been a renaissance in morphometric approaches," notes Punyasena. 

"New techniques are using easy access to high-quality digital imaging, powerful computers, and advances in computational analyses like machine learning to rethink the way we gather and analyze morphological data."

As advances in technology allow researchers to gather more and more morphological and image-based data, it has become increasingly important to be able to analyze and interpret those data quickly, accurately, consistently, and objectively. Biometric and bioinformatic methods make this possible, and reveal the potential of data collected from the shape and form of plants to be as rich of a data source as genetic data.

Access to specific articles can be found online at: http://www.bioone.org/toc/apps/2/8

Source: American Journal of Botany

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