Sunday, May 29, 2011

Trash to treasure: Turning steel-mill waste into bricks

 Scientists are reporting development and successful testing of a promising new way of using a troublesome byproduct of the global steel industry as raw materials for bricks that can be used in construction projects. Their study appears in ACS' Industrial & Engineering Chemistry Research.

In the report, Ana Andrés and colleagues note that steel mills around the world produce vast quantities of waste dust each year -- 8 million to 12 million tons in the United States, for instance, and 700,000 tons in the European Union countries. The dust often is converted into a rock-like material known as Waelz slag, which is usually disposed of in landfills. The slag contains iron, calcium, silicon oxide and other minor oxides as manganese, lead or zinc oxide. Scientists have been searching for practical and safe uses for Waelz slag. In earlier research, scientists showed that Waelz slag had potential as an ingredient in bricks, roof tiles and other ceramic products. The new research moves large-scale recycling of Waelz slag closer to reality, establishing at two real-world brick factories that the material can successfully be incorporated into commercial-size bricks.

It showed existing commercial equipment could be used to make bricks with Waelz slag, and eased concerns about large amounts of potentially toxic metals leaching out of such bricks. A small amount of potentially toxic material came out of the slag-made bricks over time, not in excess of European Union regulations. "Overall, it may be summarized that Waelz slag containing bricks meet the highest quality standards set for construction ceramic materials," the researchers say.

The authors acknowledge funding from the Spanish Ministry for Education and Science and BEFESA Steel R&D.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Journal Reference:

N. Quijorna, G. San Miguel, A. Andre´s. Incorporation of Waelz Slag into Commercial Ceramic Bricks: A Practical Example of Industrial Ecology. Industrial & Engineering Chemistry Research, 2011; 110324125033025 DOI: 10.1021/ie102145h


New nanoscale imaging may lead to new treatments for multiple sclerosis

Laboratory studies by chemical engineers at UC Santa Barbara may lead to new experimental methods for early detection and diagnosis -- and to possible treatments -- for pathological tissues that are precursors to multiple sclerosis and similar diseases.

Achieving a new method of nanoscopic imaging, the scientific team studied the myelin sheath, the membrane surrounding nerves that is compromised in patients with multiple sclerosis (MS).

The study is published in this week's online edition of the Proceedings of the National Academy of Sciences (PNAS).

"Myelin membranes are a class of biological membranes that are only two molecules thick, less than one millionth of a millimeter," said Jacob Israelachvili, one of the senior authors and professor of chemical engineering and of materials at UCSB. "The membranes wrap around the nerve axons to form the myelin sheath."

He explained that the way different parts of the central nervous system, including the brain, communicate with each other throughout the body is via the transmission of electric impulses, or signals, along the fibrous myelin sheaths. The sheaths act like electric cables or transmission lines.

"Defects in the molecular or structural organization of myelin membranes lead to reduced transmission efficiency," said Israelachvilli. "This results in various sensory and motor disorders or disabilities, and neurological diseases such as multiple sclerosis."

At the microscopic level and the macroscopic level, which is visible to the eye, MS is characterized by the appearance of lesions or vacuoles in the myelin, and eventually results in the complete disintegration of the myelin sheath. This progressive disintegration is called demyelination.

The researchers focused on what happens at the molecular level, commonly referred to as the nanoscopic level. This requires highly sensitive visualization and characterization techniques.

The article describes fluorescence imaging and other measurements of domains, which are small heterogeneous clusters of lipid molecules -- the main constituents of myelin membranes -- that are likely to be responsible for the formation of lesions. They did this using model molecular layers in compositions that mimic both healthy and diseased myelin membranes.

They observed differences in the appearance, size, and sensitivity to pressure, of domains in the healthy and diseased monolayers. Next, they developed a theoretical model, in terms of certain molecular properties, that appears to account quantitatively for their observations.

"The discovery and characterization of micron-sized domains that are different in healthy and diseased lipid assemblies have important implications for the way these membranes interact with each other," said Israelachvili. "And this leads to new understanding of demyelination at the molecular level."

The findings pave the way for new experimental methods for early detection, diagnosis, staging, and possible treatment of pathological tissues that are precursors to MS and other membrane-associated diseases, according to the authors.

All of the work reported in the paper was completed at UCSB, although some of the authors have moved to other institutions. In addition to Israelachvili, the other authors are Dong Woog Lee, graduate student in UCSB's Department of Chemical Engineering; Younjin Min, now a postdoctoral fellow in the Department of Chemical Engineering at the Massachusetts Institute of Engineering; Prajnaparamitra Dhar, now assistant professor in the Department of Chemical Engineering at the University of Kansas; Arun Ramachandran, now assistant professor in the Department of Chemical Engineering and Applied Chemistry at the University of Toronto; and Joseph A. Zasadzinski, now professor in the Department of Chemical Engineering and Materials Science at the University of Minnesota.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - Santa Barbara, via EurekAlert!, a service of AAAS.

Journal Reference:

Dong Woog Lee, Younjin Min, Prajnaparamitra Dhar, Arun Ramachandran, Jacob N. Israelachvili and Joseph A. Zasadzinski. Relating domain size distribution to line tension and molecular dipole density in model cytoplasmic myelin lipid monolayers. PNAS, May 23, 2011 DOI: 10.1073/pnas.1106368108

Ocean Optics Employee Wins Global Technology Award

Ocean Optics announced that Nelson Chandler has been awarded the Gold Award for Innovation from its parent company, Halma p.l.c. The award recognizes technology advancements made by individuals at Halma subsidiaries that have a significant impact on the company’s success.

Chandler received the L20K (USD $32K) Gold Award for Innovation, beating out 38 other entries from 22 companies in 6 countries. A software engineer at Ocean Optics, Chandler revamped the testing and calibration process for the company’s spectroscopy products, making it quicker and more reliable. By developing original software and modifying hardware equipment, he was able to make processing eight times faster, while improving consistency and quality.

Typically Innovation Award submissions involve a team working together. Chandler’s achievement is particularly impressive as he is the sole individual responsible for the improvements made. He received his B.S. in Software Engineering Technology from The University of Southern Mississippi and has been with Ocean Optics since 2007.