How a liquid drop forms is a question important for ink jet printers, paint sprayers, and other machines that emit fluids from nozzles. "Ink jet printing uses tiny drops of ink that are shot out of a nozzle using piezo action," says Osman Basaran, a professor of chemical engineering at Purdue University. He and others at Purdue did the math behind drop formation. "Another application where drop formation is critical is in DNA arraying, where ink jets spray solutions containing DNA fragments onto biochip surfaces," says Basaran. The mathematical model he helped develop computes the quickly changing pressures and velocities of fluid in evolving drops. Engineers found that the formation of droplets changes when the fluid flow is increased and decreased. They say that the findings are important for controlling the quality of sprayed materials, such as the adhesive sprayed on tapes. They also point out that fluctuations in the performance of pumps and other equipment used for spraying sometimes increases or decreases the flow rate of a system without warning, so knowing how drops form is important to improving those processes that are vulnerable. Additional applications for Basaran's work include extraction processes used in chemical, petrochemical, pharmaceutical, and metallurgic industries. More information about Basaran's work is available at http:// ChE.www.ecn.purdue.edu/ChE/Fac_.Staff/obasaran/.
In this new Design News feature, "How it Works," we’re starting off by examining the inner workings of the electronic cigarette. While e-cigarettes seemed like a gimmick just two or three years ago, they’re catching fire -- so to speak. Sales topped $1 billion last year and are set to hit $10 billion by 2017. Cigarette companies are fighting back by buying up e-cigarette manufacturers.
Microchip recently released the 3D TouchPad, the first USB PC Peripheral device that couples 2D multi-touch input with 3D air gesture technology. The company seeks the help of developers to further enhance the capabilities of the technology.
To give engineers a better idea of the range of resins and polymers available as alternatives to other materials, this Technology Roundup presents several articles on engineering plastics that can do the job.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.