. 24/7 Space News .
Pulsating dissolution found in crystals
by Staff Writers
Dresden, Germany (SPX) Jan 17, 2018

Dissolution of crystals happens in pulses, marked by waves that spread just like ripples on a pond.

When German researchers zoomed in to the nanometer scale on time-lapse images of dissolving crystals, they found a surprise: Dissolution happened in pulses, marked by waves that spread just like ripples on a pond.

"What we see are waves or rings," said lead investigator Cornelius Fischer, who conducted this research at MARUM - Center for Marine Environmental Sciences at the University of Bremen in the group of Prof. Andreas Luttge.

"We have a pit in the middle, and then around these pits are rings of mass removal."

The research is described online in the Early Edition of the Proceedings of the National Academy of Sciences.

Fischer and Luttge are specialized in studying minerals-fluid interactions, and are collaborating for more than 15 years in the US and Germany.

In everyday life, dissolving crystals is as simple as stirring sugar into a glass of water. And as any child who has made rock candy knows, the process also works in reverse: Crystals of sugar will form as water evaporates from the glass. Luttge said scientists have long known that crystals - like rock candy or the calcite found in limestone - form through a continuous process as molecules are deposited from solution into the regular crystal lattice of the solid they're becoming.

"We always thought dissolution was a continuous process, kind of like crystal formation in reverse, and we were astonished when these experiments showed this was not a continuous process," Fischer said.

"Instead, what we saw were pulses occurring around these pits."

The pulses show up clearly in rate maps, high-resolution still images that capture the rate at which material dissolves over time from the surface of a crystal. In experiments at MARUM, Cornelius Fischer modified an imaging technique called "vertical scanning interferometry" that Luttge pioneered at Rice University (Houston, USA) in the early 2000s to make "surface reaction rate maps."

"The maps show the distribution of the material flux and thus illustrate the surface reactivity," said Fischer, a former MARUM postdoctoral researcher who's now head of a research group at the independent German research laboratory Helmholtz-Zentrum Dresden-Rossendorf.

"During the routine analysis of rate-map data, we discovered the existence of a remarkable pattern of surface reactivity. This was the starting point for a systematic analysis of pulsating rate map features."

Using samples of first zinc oxide and later calcium carbonate, Fischer made maps that showed every dip and rise on the surface of crystal to a resolution of 1 nanometer or one-billionth of a meter. Each scan collected more than 4 million measurements from a surface measuring no more than a square centimeter. Taking subsequent snapshots of a crystal's surface as it dissolved allowed to measure the rate at which the crystal dissolved as a function of surface height.

Scientists have long understood the importance that tiny surface defects play in crystal dissolution. Miniscule divots called etch pits expose crystal edges and increase the likelihood that a solvent, like water, will chemically react with atoms from the crystal. The process is similar to how rust eats away at iron or steel.

When they examined their rate maps for dissolving calcite and zinc oxide crystals, Luttge and Fischer found "rhythmic fluctuations of the reactive surface site density," or dissolution pulses that spread like rings from etch pits and screw dislocations, much like ripples that spread from the point where a pebble is dropped into a pond.

"The complex superimposition of pulses defines the overall result, and we are now able to understand - and, most importantly, to quantify - such patterns as the starting point for the formation of porosity in solid materials during dissolution," Fischer said.

Luttge said the discovery adds to scientists' fundamental understanding of crystal dissolution and could aid researchers in fields as diverse as corrosion prevention and pharmaceutical manufacturing.

Bacteria makes blue jeans green
Paris (AFP) Jan 8, 2018
They can be tight, flared, ripped at the knee. Jeans come in all styles and colours these days, but one hue will always be synonymous with the world's favourite garment: indigo blue. To satisfy the world's seemingly insatiable demand for blue denim, more than 45,000 tonnes of indigo dye are produced every year, with much of the waste making its way into rivers and streams, conservationists s ... read more

Related Links
Helmholtz-Zentrum Dresden-Rossendorf
Space Technology News - Applications and Research

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Top takeaways from Consumers Electronics Show

Gadgets for kids still big at tech show despite concerns

'To boldly grow': Japan astronaut worried by space growth spurt

Tech a new religion at consumer gadget extravaganza

Arianespace begins building final 10 Ariane 5s ahead of Ariane 6 operational debut

SpaceX says rocket worked fine as spy satellite reported lost

Arianespace prepares for a busy 2018

Dragon space truck set for departure from Space Station

Exploring alien worlds with lasers

Opportunity Takes Images Over the Holiday Period

Our rover could discover life on Mars - here's what it would take to prove it

Opportunity takes extensive imagery to decide where to go next

Scientist reveals what is so special about Chines's next moon mission

China's Kuaizhou-11 rocket scheduled to launch in first half of 2018

Nation 'leads world' in remote sensing technology

China plans for nuclear-powered interplanetary capacity by 2040

Aerospace Workforce Training - National Mandate for 2018

Intelsat signs contract with Arianespace for two launches

Nationwide search begins for young space entrepreneurs

Russia restores contact with Angolan satellite

Breaking bad metals with neutrons

EU unveils supercomputer plan to rival China

Russian scientists found excitons in nickel oxide for the first time

Bacteria makes blue jeans green

Iron-Rich Stars Host Shorter-Period Planets

SETI project homes in on strange 'fast radio bursts'

Extraterrestrial Hypatia stone rattles solar system status quo

Planets around other stars are like peas in a pod

New Year 2019 offers new horizons at MU69 flyby

Study explains why Jupiter's jet stream reverses course on a predictable schedule

New Horizons Corrects Its Course in the Kuiper Belt

Does New Horizons' Next Target Have a Moon?

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.