Current Research
Miniature Mass Spectrometry for Chemical/Biological Analysis
A mass spectrometer is a chemical instrument that analyzes the chemical composition of a compound or sample by separating the particles based on their mass. Mass spectrometers are powerful tools with applications including environmental monitoring, bioterrorism prevention, and the study of proteins and other biological samples. Historically, mass spectrometers have been laboratory-based tools because of the size of the components and supporting equipment. Recent efforts have focused on developing miniature mass spectrometers with sizes ranging from millimeter-scale components to micrometer-scale components. By miniaturizing mass spectrometers, these instruments can be brought into field application for in situ chemical analysis.
Mass spectrometers work by taking the compound or sample in question and ionizing it to create charged particles. The ions can then be accelerated and transported using magnetic or electric fields in order to sort them by their mass. A detector detects the sorted ions, and the chemical constituents of the sample can be determined. However, there are still many challenges that impede the development of efficient miniature mass spectrometers. Understanding the motion and transport of ions in mass spectrometers is essential to designing more effective components. The current focus of this research is on using particle image velocimetry (PIV) and similar velocimetry techniques to study the motion of ions and neutral molecules as ions are injected into a mass spectrometer. Computational techniques, including particle simulations, are used to complement the experiments in order have a more complete understanding of the electrohydrodynamics during ion injection.
Thermal Transport in Carbon Nanomaterials
In recent years, novel nanomaterials have been developed which have superior electrical and thermal performance. These materials offer the potential to revolutionize the next generation of the transistors and thermoelectrics for energy conversion. Carbon-based, nanostructured materials such as carbon nanotubes and graphene (a single layer of carbon atoms) have very high thermal conductivity which makes them attractive thermal materials. This research seeks to develop increased understanding of multi-scale thermal transport in structures that transition from a nanostructure to a bulk material. The current focus is on developing a theoretical framework for the thermal conductivity in carbon nanomaterials. Molecular dynamics (MD) simulations are employed to describe the crystal dynamics and predict the thermal conductivity of graphene, and the results will be compared to experimental measurements of the thermal conductivity.
Selected Recent Publications
D. B. Go, T. S. Fisher, S. V. Garimella, V. B. Bahadur “Planar microscale ion generation devices in atmospheric air with diamond-based electrodes,” Plasma Sources Sci. Tech. – in preparation
D. B. Go, T. S. Fisher, S. V. Garimella “Direct simulation of ionization and ion transport for planar microscale ion generation devices,” J. Phys. D: Appl. Phys. – in preparation
D. B. Go, R. A. Maturana, T. S. Fisher, S. V. Garimella “Enhancement of external forced convection by ionic wind,” Int. J. Heat Mass Transfer – in press
D. B. Go, S. V. Garimella, T. S. Fisher, R. K. Mongia “Ionic winds for locally enhanced cooling,” J. Appl. Phys., vol. 102, art. no. 053302, 2007.
- also in Virtual Journal of Nanoscale Science and Technology, vol. 16, no. 14, 2007.
Direct comments, questions, and corrections to amedept@nd.edu