PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Liquids on fibers -- slipping or flowing?

Scientists reveal different dynamics of droplet formation on fibers

2015-07-01
(Press-News.org) Thin fibers play a tremendous role in many areas of our daily life, from the use of glass fibers in ultra-fast data transmission to textile fibers in our clothing. In order to enable special properties of these fibers, they are often coated with a thin liquid layer that is supposed to be stable and homogeneous. However, for the production of drinkable water, the exact opposite features are desired: there, one aims at harvesting water, which is transported along the fiber as a liquid film or as liquid droplets, from fog. Now, scientists have been able to reveal, by means of lacquer films on glass fibers, whether liquid films slowly flow along the fiber or if they can slip faster on the fiber. The team composed of Karin Jacobs and Sabrina Haefner from Saarland University, together with Oliver Bäumchen from the Max Planck Institute for Dynamics and Self-Organization in Göttingen, and colleagues from Canada and France have been able to show for the first time, by means of novel experiments and mathematical models, how a liquid film moves on a fiber, depending on the fiber coating. The results of this study have now been published in the high-ranked journal "Nature Communications".

Many examples for liquids on fibers are known in nature. Just think about dew droplets on spider webs that you can observe during a walk in the morning. Indeed, humidity is collected on the fiber as droplets, as the liquid surface can be minimized this way. This phenomenon, which can also be observed for a stream of water flowing out of a faucet, is named the Rayleigh-Plateau instability. "All systems drive towards their energetic minimum, and that is the droplet shape in this case", says Sabrina Haefner, a physicist in the research group of Karin Jacobs. This instability can be very useful in very dry and remote regions of the world. For example, in Chile's Atacama desert, the acquisition of drinkable water is essential for the locals and they harvest water from the humidity by means of fiber nets.

In industrial applications, however, it is often necessary to realize stable and homogeneous liquid films on fibers. So how does one manage to avoid this droplet formation? "The surface energy of the liquid, its viscosity, the thickness of the liquid film, as well as the diameter of the fiber, play an important role", explains Karin Jacobs. The international team of researchers has now found that the properties of the fiber itself also have a strong impact. "The contact between the liquid and the fiber is indeed very important", says Oliver Bäumchen from the Max Planck Institute for Dynamics and Self-Organization. "If the liquid slips on the fiber surface, the droplet formation is much faster than in the case of just flow along the fiber". The team of physicists tested this for liquid films supported by uncoated and Teflon-coated fibers. On uncoated fibers, the liquid film moved rather slowly, and droplet formation took longer, than on coated fibers, where the liquid film was able to slip. "In line with mathematical models, these experiments allow for quantifying 'slippage' of liquid films and to precisely predict the dynamics of the droplet formation process", says Sabrina Haefner from Saarland University. The team of researchers agrees: Their results are very important for the design of novel fiber coatings.

INFORMATION:

The international team of researchers is composed of experimental and theoretical physicists from Saarland University (Saarbrücken, Germany), the Max Planck Institute for Dynamics and Self-Organization (Göttingen, Germany), McMaster University (Hamilton, Canada) and the ESPCI (Paris, France).

The study by S. Haefner, M. Benzaquen, O. Bäumchen, T. Salez, R. Peters, J.D. McGraw, K. Jacobs, E. Raphaél, and K. Dalnoki-Veress with the title "Influence of Slip on the Plateau-Rayleigh Instability on a Fibre" has been published in the high-ranked journal "Nature Communications": http://www.nature.com/ncomms/2015/150612/ncomms8409/full/ncomms8409.html

A picture from the study can be downloaded here: http://www.uni-saarland.de/pressefotos

A video from the study can be found here: https://www.youtube.com/watch?v=jxEUfXvQ_Ms

Contact:

Prof. Dr. Karin Jacobs
Saarland University, Experimental Physics
Tel.: 0049 - 681 302-71788
E-Mail: k.jacobs@physik.uni-saarland.de
http://www.uni-saarland.de/jacobs

Dr. Oliver Bäumchen
Max Planck Institute for Dynamics and Self-Organization Göttingen
Tel.: 0049 - 551 5176-260
E-Mail: oliver.baeumchen@ds.mpg.de
http://www.dcf.ds.mpg.de



ELSE PRESS RELEASES FROM THIS DATE:

Observing the birth of a planet

2015-07-01
This news release is available in German. Observing time at the European Southern Observatory (ESO) on Paranal Mountain is a very precious commodity - and yet the Very Large Telescope (VLT) in Chile spent an entire night with a high-resolution infrared camera pointed at a single object in the night sky. The data collected by the Naco optics instrument enabled an international team headed by ETH Zurich's Sascha Quanz to confirm its earlier hypothesis: that a young gas planet - presumed not unlike Jupiter in our own solar system - is orbiting the star designated HD 100546. At ...

Effective conversion of methane by a new copper zeolite

Effective conversion of methane by a new copper zeolite
2015-07-01
This news release is available in German. A new bio-inspired zeolite catalyst, developed by an international team with researchers from Technische Universität München (TUM), Eindhoven University of Technology and University of Amsterdam, might pave the way to small scale 'gas-to-liquid' technologies converting natural gas to fuels and starting materials for the chemical industry. Investigating the mechanism of the selective oxidation of methane to methanol they identified a trinuclear copper-oxo-cluster as the active center inside the zeolite micropores. In ...

Doing good deeds helps socially anxious people relax

2015-07-01
Being busy with acts of kindness can help people who suffer from social anxiety to mingle more easily. This is the opinion of Canadian researchers Jennifer Trew of Simon Fraser University and Lynn Alden of the University of British Columbia, in a study published in Springer's journal Motivation and Emotion. Sufferers from social anxiety are more than just a little shy. Dealings with others might make them feel so threatened or anxious that they often actively avoid socializing. Although this protects them from angst and possible embarrassment, they lose out on the support ...

Sexual harassment at work not just men against women

2015-07-01
More than one in ten complaints of sexual harassment at work are reported by men, a QUT study has found. According to the research, conducted by Professor Paula McDonald from the QUT Business School and Professor Sara Charlesworth from RMIT, women were accused of sexually harassing men in 5 per cent of cases and men accused other men in 11 per cent of cases. Workplace sexual harassment at the margins, published in the Work, Employment and Society journal, analysed sexual harassment complaints lodged with Australian equal opportunity commissions in the six months from ...

Evaluation of NK1 antagonists for emesis prevention in oxaliplatin chemo: SENRI trial

2015-07-01
BARCELONA-LUGANO, 1 July 2015 - The SENRI trial has opened the window to evaluate NK1 antagonists for emesis prevention in patients taking oxaliplatin chemotherapy, antiemetics expert and ESMO spokesperson Fausto Roila said, putting into perspective the results of a Japanese study presented today at the ESMO 17th World Congress on Gastrointestinal Cancer 2015 in Barcelona. Roila's comments came as the SENRI Trial results were presented including a new gender analysis (1),(2). He said: "Until now we said that NK1 antagonists have no role in the prevention of emesis in ...

Patients with lowest BMI have shortest survival in pooled analysis of bev in mCRC

2015-07-01
BARCELONA-LUGANO, 1 July 2015 - Patients with the lowest body mass index (BMI) had the shortest overall survival in an analysis of bevacizumab studies in metastatic colorectal cancer (mCRC) presented for the first time today at the ESMO 17th World Congress on Gastrointestinal Cancer 2015 in Barcelona.(1) "There is good evidence that obesity increases the risk of getting colorectal cancer and that it increases the risk of colorectal cancer recurrence after curative therapy," said lead study author Dr Yousuf Zafar, associate professor of medicine at Duke Cancer Institute ...

Thin colorectal cancer patients have shorter survival than obese patients

Thin colorectal cancer patients have shorter survival than obese patients
2015-07-01
DURHAM, N.C. - Although being overweight with a high body-mass index (BMI) has long been associated with a higher risk for colorectal cancer, thinner patients might not fare as well after treatment for advanced cancer, according to a new study from Duke Medicine. The study, which was presented today at the European Society for Medical Oncology World Congress on Gastrointestinal Cancer, found that patients with a low to healthy body weight lived an average of two-and-a-half months less than overweight and obese patients. The results surprised researchers, who expected ...

Deuterium substitution improves therapeutic and metabolic profiles of medicines

2015-07-01
Lexington, Mass., July 1, 2015 - Substituting deuterium for certain hydrogen atoms in molecules has been shown to enhance the metabolic properties of a number of drugs and provides a promising approach to the discovery and development of innovative drug products. The deuterium chemistry approach has the potential to reduce the high failure rates of conventional drug development by building on the known pharmacology of existing compounds and leveraging their desirable therapeutic properties. Selective deuterium substitution as a means of ameliorating unwanted clinically ...

Experimental drug combined with standard chemo may shrink ovarian cancers

2015-07-01
Working in cell cultures and mice, researchers at Johns Hopkins have found that an experimental drug called fostamatinib combined with the chemotherapy drug paclitaxel may overcome ovarian cancer cells' resistance to paclitaxel. Scientists elsewhere are already testing fostamatinib in people with lymphoma and idiopathic thrombocytopenia purpura, an autoimmune disorder. Based on results of the current study described in a report online June 18 in the journal Cancer Cell, Johns Hopkins researchers say they are planning a phase I clinical trial to test the paclitaxel-fostamatinib ...

Producing spin-entangled electrons

2015-07-01
A team from the RIKEN Center for Emergent Matter Science, along with collaborators from several Japanese institutions, have successfully produced pairs of spin-entangled electrons and demonstrated, for the first time, that these electrons remain entangled even when they are separated from one another on a chip. This research could contribute to the creation of futuristic quantum networks operating using quantum teleportation, which could allow information contained in quantum bits--qubits--to be shared between many elements on chip, a key requirement to scale up the power ...

LAST 30 PRESS RELEASES:

Being physically active, even just a couple of days a week, may be key to better health

High-fat diet promote breast cancer metastasis in animal models

A router for photons

Nurses and AI collaborate to save lives, reduce hospital stays

Multi-resistance in bacteria predicted by AI model

Tinker Tots: A citizen science project to explore ethical dilemmas in embryo selection

Sensing sickness

Cost to build multifamily housing in California more than twice as high as in Texas

Program takes aim at drinking, unsafe sex, and sexual assault on college campuses

Inability to pay for healthcare reaches record high in U.S.

Science ‘storytelling’ urgently needed amid climate and biodiversity crisis

KAIST Develops Retinal Therapy to Restore Lost Vision​

Adipocyte-hepatocyte signaling mechanism uncovered in endoplasmic reticulum stress response

Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid

Low LDL cholesterol levels linked to reduced risk of dementia

Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients

Almost one in ten people surveyed report having been harmed by the NHS in the last three years

Enhancing light control with complex frequency excitations

New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients

New insight into factors associated with a common disease among dogs and humans

Illuminating single atoms for sustainable propylene production

New study finds Rocky Mountain snow contamination

Study examines lactation in critically ill patients

UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award

Doubling down on metasurfaces

New Cedars-Sinai study shows how specialized diet can improve gut disorders

Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana

PKU Scientists simulate the origin and evolution of the North Atlantic Oscillation

ICRAFT breakthrough: Unlocking A20’s dual role in cancer immunotherapy

How VR technology is changing the game for Alzheimer’s disease

[Press-News.org] Liquids on fibers -- slipping or flowing?
Scientists reveal different dynamics of droplet formation on fibers