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Seashells inspire better concrete

July 10, 2024 By EarthWise Leave a Comment

Mother of pearl – also known as nacre – is a natural material found in certain seashells such as those of oysters and abalone. On the microscopic level, it consists of hexagonal tablets of the hard mineral aragonite glued together by a soft biopolymer. The aragonite gives nacre its strength, and the biopolymer adds flexibility and crack resistance.

Scientists at Princeton University have developed innovative composite materials inspired by nacre by utilizing conventional construction materials like Portland cement paste combined with a limited amount of polymer. The new material consists of alternating layers of cement paste sheets with the highly stretchable polymer polyvinyl siloxane.

The materials were subjected to bending tests to evaluate crack resistance or fracture toughness. Three different versions of the material were tested that used different ways of interposing the polymer layers. The new materials were compared with similar structures composed entirely of cement.

The concrete-only samples were brittle, breaking suddenly and completely upon reaching their failure point. The samples with alternating cement and polymer layers demonstrated increased ductility and resistance to cracking.

By fully mimicking the structure of nacre – using completely separated hexagonal cement tablets – the researchers demonstrated materials with 19 times the ductility and 17 times the fracture toughness of cement while retaining nearly the same strength as solid cement samples.

Engineered materials inspired by nature could eventually help increase the durability of a wide range of brittle ceramic materials, from concrete to porcelain.

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From seashells to cement, nature inspires tougher building material

Photo, posted January 2, 2016, courtesy of Yantra via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving Energy At Data Centers | Earth Wise

February 17, 2020 By EarthWise Leave a Comment

A data center is a building, dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and data storage systems. Data centers are the backbone of internet services and cloud computing, which together are increasingly dominant elements of modern life.

Energy use is a central issue for data centers. Power used by them ranges from a few kilowatts for a rack of servers in a closet at a local business to several tens of megawatts for large facilities. Some data centers have power densities more than 100 times that of a typical office building and use as much electricity as several thousand homes. For such facilities, electricity costs are a dominant operating expense and account for over 10% of the total cost of ownership of a data center.These centers, with their numerous racks of computer servers, consume 90 billion kilowatt-hours of electricity each year in the United States, as much as all of our residences use for lighting.

A research group at Princeton University is developing a family of devices that can dramatically reduce power consumption at data centers. The team’s technology focuses on the process by which the AC power from the grid is converted to the low-voltage direct current used by computer equipment. With existing technology, this power conversion takes place in each individual computer, which ends up wasting about 40% of the original energy. The new device aggregates power conversion into a single unit, which then distributes the power to the individual computers and storage units.

As data centers get bigger and more numerous, the opportunity to save a lot of energy becomes increasingly important.

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New technology boosts energy eﬃciency in data centers

Photo, posted June 8, 2007, courtesy of Sean Ellis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar And Wind Energy And Groundwater

December 30, 2019 By EarthWise Leave a Comment

The use of both solar and wind farms has been expanding all over the country as a way of lowering carbon emissions from the electric power sector. According to a new study led by Princeton University, these renewable energy sources have another important benefit: they keep more water in the ground.

The study focused on drought-prone California where both solar and wind power have been expanding dramatically. California is the largest agricultural producer in the United States and has also experienced one of the most severe droughts on record between 2012 and 2017.

The study determined that increased solar and wind energy can reduce the reliance on hydropower, especially during times of drought.

The study looked at multiple scenarios in order to determine how much solar and wind energy should be used to maximize economic revenue and to see how solar and wind power could ensure groundwater recovery. They created a framework to quantify the optimal pathways for maximizing hydroelectricity and agricultural income while avoiding groundwater depletion.

During the long drought, California’s agriculture industry relied heavily on tapping into groundwater stores, which is an unsustainable practice. With more droughts likely to occur in California as well as increasing water demand from the growing California population, the burden on the state’s groundwater supply will only grow.

According to the researchers, it is far more practical to impose further regulations on groundwater use if sufficient solar and wind power is deployed. They caution that these resources need to be deployed long before groundwater aquifers are depleted, or it will be too late for them to do any good.

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Solar and Wind Energy Preserve Groundwater for Drought, Agriculture

Photo, posted December 11, 2014, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.