Structural Biology Research Advances Combustion Science


A new detector developed in the BER Structural Biology Instrumentation Research program is leading to understanding of the dynamics of fuel sprays in diesel and gasoline engines. The new device, known as a Pixel Array Detector (PAD), is being developed at Cornell University in order to increase the speed of obtaining data sets in protein crystallography experiments at synchrotron light sources. The goal is to obtain complete images in microseconds instead of in a second as the current detectors require. This would allow completion of experiments with fragile protein crystals before they break down in the intense x-ray beam. A PAD module has now been used to image the change over microsecond time periods of the fuel spray from a diesel engine fuel injector. Studies were carried out at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL) and at the Cornell High Energy Synchrotron Source (CHESS) at Cornell University. The images obtained with the PAD show development of a supersonic shock wave as the leading edge of the spray reaches speeds well above the speed of sound in the medium very soon after injection. The results are reported in the February 15, 2002, issue of Science. The on-line version of the article includes an animated sequence of x-radiographic images of the shock wave. The Cornell group is directed by Physics Professor Sol Gruner, who is also Director of the CHESS, and is funded by the Office of Biological & Environmental Research. The ANL group is lead by Jin Wang at the APS and receives funding from the Office of Basic Energy Sciences and DOE’s FreedomCAR Program.