How aerosols are formed
2021-01-14
(Press-News.org) Aerosols are suspensions of fine solid particles or liquid droplets in a gas. Clouds, for example, are aerosols because they consist of water droplets dispersed in the air. Such droplets are produced in a two-step process: first, a condensation nucleus forms, and then volatile molecules condense onto this nucleus, producing a droplet. Nuclei frequently consist of molecules different to those that condense onto them. In the case of clouds, the nuclei often contain sulphuric acids and organic substances. Water vapour from the atmosphere subsequently condenses onto these nuclei.
Scientists led by Ruth Signorell, Professor at the Department of Chemistry and Applied Biosciences, have now gained new insights into the first step of aerosol formation, nucleation. "Observations have shown that the volatile components can also influence the nucleation process," Signorell says, "but what was unclear was how this was happening at the molecular level." Previously it was impossible to observe the volatile components during nucleation in an experimental setting. Even in a famous CERN experiment on cloud formation, the "Cloud" experiment, certain volatile components could not be directly detected.
Volatile components detected for the first time
The ETH researchers developed an experiment aimed at the first microseconds of the nucleation process. In the experiment, the particles formed remain intact during this time and can be detected using mass spectrometry. The scientists looked at nucleation in various gas mixtures containing CO2 and for the first time, they were able to detect the volatile components as well - in this case, the CO2. The researchers could show that the volatile components were essential for the formation of nuclei and also accelerated this process.
An analysis of the experimental data revealed that this acceleration is the result of the volatile components catalysing the nucleation of other, less volatile components. They do this by forming short-lived, heterogeneous molecular aggregates, known as chaperon complexes. "Because temperature determines the volatility of gas components, it also plays a decisive role in these processes," Signorell explains.
One reason the new research results are interesting is that they improve the understanding of nucleation, its molecular mechanisms and speed, in order to properly account for it in models for, say, cloud formation in the atmosphere. In addition, the results should help to improve the efficiency of technical processes for producing aerosols - such as the use of rapid cooling to capture CO2 from natural gas.
INFORMATION:
Reference
Li C, Krohn J, Lippe M, Signorell R: How volatile components catalyze vapor nucleation, Science Advances, 13 January 2021, doi: 10.1126/sciadv.abd9954
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-01-14
Leading cancer experts at the University of Birmingham have solved a long-standing question of how various types of mutations in just one gene cause different types of diseases.
A team of scientists at the University's Institute of Cancer and Genomic Sciences, led by Professor Constanze Bonifer, studied a gene known as RUNX1, which is responsible for providing instructions for the development of all blood cells and is frequently mutated in blood cancers.
The results of their research has shown that the balance of cells types in the blood is affected much earlier than previously thought, which is particularly important for families that carry ...
2021-01-14
Adaptability explains why insects spread so widely and why they are the most abundant animal group on earth. Insects exhibit resilient and flexible locomotion, even with drastic changes in their body structure such as losing a limb.
A research group now understands more about adaptive locomotion in insects and the mechanisms underpinning it. This knowledge not only reveals intriguing information about the biology of the insects, but it can also help to design more robust and resilient multi-legged robots that are able to adapt to similar physical damage.
The insect nervous system is comprised of approximately 105 to 106 neurons. Understanding ...
2021-01-14
Posidonia oceanica seagrass -an endemic marine phanerogam with an important ecological role in the marine environment- can take and remove plastic materials that have been left at the sea, according to a study published in the journal Scientific Reports. The article's first author is the tenure-track 2 lecturer Anna Sànchez-Vidal, from the Research Group on Marine Geosciences of the Faculty of Earth Sciences of the University of Barcelona (UB).
The study describes for the first time the outstanding role of the Posidonia as a filter and trap for plastics in the coastal areas, and it is pioneer ...
2021-01-14
Both past and present-day scientists have suspected the intestines of playing a role in various diseases. Present-day studies focus on the intestinal flora's role in physical diseases such as diabetes and overweight, while others seek to establish a connection between the intestinal flora and e.g. autism, schizophrenia and depression. But even modern-day scientists have difficulties studying the around 500-1000 different species among the approx. 100 billion active bacteria in our intestines.
Therefore, researchers from the University of Copenhagen have developed a ground-breaking technique that ...
2021-01-14
Roughly 8,200 years ago, the island of Yuzhniy Oleniy Ostrov in Lake Onega in the Republic of Karelia, Russia, housed a large burial ground where men, women and children of varying ages were buried. Many of the graves contain an abundance of objects and red ochre, signifying the wish to ensure the comfort of the buried also after death. Pendants made of elk incisors were apparently attached to clothing and accessories, such as dresses, coats, cloaks, headdresses and belts. Although no clothing material has been preserved, the location of the elk teeth sheds light on the possible type of these outfits.
A people of grooved elk tooth pendants
A study headed by archaeologist Kristiina Mannermaa, University of Helsinki, aimed to determine who ...
2021-01-14
Bacteria are likely triggering greater melting on the Greenland ice sheet, possibly increasing the island's contribution to sea-level rise, according to Rutgers scientists.
That's because the microbes cause sunlight-absorbing sediment to clump together and accumulate in the meltwater streams, according to a Rutgers-led study - the first of its kind - in the journal Geophysical Research Letters. The findings can be incorporated in climate models, leading to more accurate predictions of melting, scientists say.
"These streams can be seen all over Greenland ...
2021-01-14
In patients with bladder cancer, chemotherapy effectiveness is partially determined by the body's immune system response to the malignancy. This is the conclusion of research conducted by a team of scientists from Charité - Universitätsmedizin Berlin and the Berlin Institute of Health. The findings, which have been published in Science Translational Medicine*, can be used to predict treatment success and may increase survival in patients with bladder cancer.
Bladder cancer is one of the ten most common types of cancer in Germany, and one of the five most common cancers in men. Nationwide, the disease affects approximately 30,000 people a year. The risk of the cancer ...
2021-01-14
TAMPA, Fla. -- The hallmarks of cancer include rapid cell reproduction and metabolic activity. But these processes also lead to increased cellular stress and oxidation, and the risk of cell death. To circumvent these negative consequences of supercharged growth, cancer cells stimulate pathways to reduce oxidative stress and avoid cell death. In an article published in Cell Metabolism, Moffitt Cancer Center researchers report on a newly discovered biochemical pathway that protects cells from a type of cell death called ferroptosis.
Ferroptosis is a specialized type of cell death that is caused ...
2021-01-14
Scientists at the Walter Reed Army Institute for Research have shown that microRNA biomarkers related to Alzheimer's disease play a role in brain damage caused by traumatic brain injury.
TBI or brain trauma results from blows to the head, leading to chronic disruption of the brain and a cascade of long-term health conditions. Patients who suffer from TBI are at much higher risk of developing neurodegenerative disease or dementia, particularly Alzheimer's disease. The mechanism behind this relationship remains understudied, making the development effective therapeutics challenging.
MiRNAs are small pieces of genetic material that play a critical role in normal gene expression. Yet, studies have also linked abnormal miRNA levels, or dysregulation, to a range of diseases including neurodegenerative ...
2021-01-14
Recently, the research team led by academician GUO Guangcan from the University of Science and Technology of China of the Chinese Academy of Sciences has made security analysis and improvement of source independent quantum random number generators with imperfect devices.
By studying the actual characteristics of the measurement devices of the source-independent quantum random number generation, the researchers pointed out that the security issues were caused by afterpulse, detection efficiency mismatching, poor sensitivity to photon number distribution ...
LAST 30 PRESS RELEASES:
[Press-News.org] How aerosols are formed
