Featured Research

from universities, journals, and other organizations

Pesticide additives cause drifting droplets, but can be controlled

Date:
March 20, 2012
Source:
Purdue University
Summary:
Chemical additives that help agricultural pesticides adhere to their targets during spraying can lead to formation of smaller "satellite" droplets that cause those pesticides to drift into unwanted areas, researchers have found.

Simulations and high-speed visualization reveal a synergistic effect between chemical additives that can lead to the formation of satellite droplets during crop spraying. Emission of satellite droplets - shown here between two main drops - is also detrimental in a number of applications ranging from food processing to rocket propulsion systems.
Credit: Purdue University image

Chemical additives that help agricultural pesticides adhere to their targets during spraying can lead to formation of smaller "satellite" droplets that cause those pesticides to drift into unwanted areas, Purdue University researchers have found.

Related Articles


Carlos Corvalan, an associate professor of food science, said understanding how the additives work together means they could be designed to decrease the health, environmental and property damage risks caused by drift. Corvalan; Osvaldo Campanella, a Purdue professor of agricultural and biological engineering; and Paul E. Sojka, a Purdue professor of mechanical engineering, published their results in a February issue of the journal Chemical Engineering Science.

"When we spray liquids, we have what we call main drops, which are drops of the desired size, and we can also have smaller satellite drops. The smaller drops move easily by wind and travel long distances," Corvalan said. "Now that we know better how additives influence the formation of satellite droplets, we can control their formation."

The research will also have applications in food processing and rocket propulsion, where drop sizes are important.

When liquids are sprayed, they start in a stream and eventually form drops. As the liquids move farther in the air, drops connected by a thin filament start to pull apart. That filament eventually detaches and becomes part of the drops that were forming on either side of it.

Satellite droplets form in the middle of filaments of pesticides containing surfactants and polymeric additives, which help the pesticides wet and adhere to plant surfaces. The surfactants reduce surface tension and force round drops to flatten, helping them cover more surface area on a sprayed plant's leaves. The polymeric additives reduce viscosity -- liquid resistance -- making the pesticide flow easier. Polymeric additives also keep the drops from bouncing off plant surfaces.

"Each additive is designed to improve the characteristics of the main drops," Corvalan said. "But there is a side effect."

When both additives are present in a pesticide, the surfactant pushes more liquid toward the filament. The reduced viscosity allows liquid to flow more easily in that direction, resulting in a well-defined satellite drop forming in the filament.

"When you put both additives together, there is a synergistic effect. The force induced by the surfactant that was opposed by viscosity is no longer so strongly opposed, and this combined effect can result in the formation of satellite droplets," Corvalan said.

Drifting of agricultural pesticides not only increases waste and cost for farmers but also can cause health, environmental and property damage, according to the U.S. Environmental Protection Agency.

The results show that carefully modulating the strength, concentration or ratio of surfactants to polymer additives can mitigate or eliminate the formation of unwanted satellite droplets.

Corvalan is now transferring the results obtained from agricultural research into food processing and rocket propulsion work. He said drop size uniformity is as important for fuels sprayed into rocket combustion chambers as for the production of food emulsions.

The U.S. Department of Agriculture National Institute of Food and Agriculture, Air Quality Program, and the Army Research Office funded the work.


Story Source:

The above story is based on materials provided by Purdue University. The original article was written by Brian Wallheimer. Note: Materials may be edited for content and length.


Journal Reference:

  1. Rajeswari J. Muddu, Jiakai Lu, Paul E. Sojka, Carlos M. Corvalan. Threshold wavelength on filaments of complex fluids. Chemical Engineering Science, 2012; 69 (1): 602 DOI: 10.1016/j.ces.2011.11.023

Cite This Page:

Purdue University. "Pesticide additives cause drifting droplets, but can be controlled." ScienceDaily. ScienceDaily, 20 March 2012. <www.sciencedaily.com/releases/2012/03/120320141948.htm>.
Purdue University. (2012, March 20). Pesticide additives cause drifting droplets, but can be controlled. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2012/03/120320141948.htm
Purdue University. "Pesticide additives cause drifting droplets, but can be controlled." ScienceDaily. www.sciencedaily.com/releases/2012/03/120320141948.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Raw: Baby Okapi Born at Houston Zoo

Raw: Baby Okapi Born at Houston Zoo

AP (Nov. 20, 2014) The Houston Zoo released video of a male baby okapi. Okapis, also known as the "forest giraffe", are native to the Democratic Republic of the Congo in Central Africa. Video is mute from source. (Nov. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins