Ben H. Jansen - US grants

Potential problems with mechanical equipment are often revealed by sound and vibration. The acoustic signals therefrom are often used to diagnose defects and monitor the performance of the equipment. The technology is not fully developed and can benefit from further study. There are economic incentives to perfect such diagnostic systems since they promise to provide the capability of rapid inspection of large machines or structures with minimal interruption of operations. Improving the sensitivity of such systems and minimizing their potential for false alarms would represent a major step in advancing the technology. This project addresses that goal. It could lead to new ways of processing acoustic signals in order to extract the maximum amount of useful information. The beam is chosen as the object of study because it is a basic structural component and because there is an extensive theoretical literature on its vibrational modes, including the effect of cracks. There is a variety of uncertainties in the condition of beams in service which can cause variations in their acoustic signatures. These uncertainties may arise from manufacturing variations in dimensions and materials, wear, miscellaneous nicks and dents, small delaminations, corrosion, dirt or internal stress. If changes in the acoustic signatures of the beam caused by these harmless effects are great enough, they may be the cause of false alarms in a detection system. This project's goal is to be able to predict the extent of such effects and to compare them with the effects of flaws of serious concern. The research program concentrates on the modeling of unflawed vibrating beams and the construction of an experimental fixture for laboratory data acquisition. The system modeling effort focuses on the prediction of the response of unflawed beams, the prediction of the response of cracked beams, and the preliminary prediction of the effects of various other conditions specified above. The experimental fixture activity focuses on the design of a test fixture, its fabrication and assembly, data acquisition from unflawed beams, data acquisition from flawed beams, data acquisition from beams of uncertain condition, and comparison of signals from these experiments.

This project deals with the development of systems which use acoustic signals to monitor the performance of equipment. There is a wide variety of potential applications for such acoustic monitoring systems. As sensors and computer hardware become smaller and less expensive, all manner of machines and structures could be provided with "nerve systems" to assess their health. This project involves three phases, comprising 1) modeling of acoustic systems, 2) data acquisition and signal processing, and 3) system identification. The system envisioned ultimately will consist of an acoustic excitation, a transmission path, one or more receivers, and hardware for signal processing and computation. The monitoring of beams for cracks will be considered as a specific example.

DESCRIPTION (provided by applicant): In this proposal, we aim to develop a fully integrated ferrofluidic microchip to magnetically manipulate and enrich cells inside bio-compatible ferrofluids in a label-free manner by combining microfluidics and dynamically-reconfigurable wire-mesh coils. Goals of this research are (1) to develop the ferrofluidic microchip as a general cell manipulation platform for biomedical research, and (2) to develop a fast and low-cost front-end separation method to enrich cervical abnormal cells for increased reproducibility, reduced screening time, and improved screening accuracy. We plan to achieve these goals through pursuing three specific aims. (1) Development of integrated ferrofluidic cell manipulation and enrichment microchip. We will model, design, fabricate and test a novel and versatile wire-mesh coil to produce reconfigurable and dynamic magnetic field patterns. A PDMS microchannels will be designed and integrated with the wire-mesh coil to form the prototype chip. (2) Demonstration of the chip's effectiveness in cell manipulation. We will develop bio-compatible ferrofluids for live cell experiments. We will exploit size, shape and elasticity of cells as potenial manipulation characteristics. Cell manipulation will be conducted with live cells. (3) Application of chip in cervical cancer cell enrichment. The chip can be applied in areas in cell biology where understanding of cell behavior requires isolation and manipulation of certain cell subpopulations. This is a highly interdisciplinary research project because it deals with the themes of colloidal chemistry, fluid dynamics, magnetism, electronics, modeling and simulation, microfabrication, and cancer biology. An interdisciplinary team in both engineering sciences (University of Georgia and University of Houston) and cancer biology (Centers for Disease Control and Prevention) is formed for this project. The team includes 4 university faculty, one CDC cervical cancer expert, one CDC postdoctoral scholar, and two graduate students. The duration of the proposed project period is 3 years. PUBLIC HEALTH RELEVANCE (provided by applicant): The chip can be applied in areas in cell biology where understanding of cell behavior requires isolation and manipulation of certain cell subpopulations. The chip will be used to enrich abnormal cervical cells and support the effort for better prevention and control of cervical cancer, which is the second most common cancer in women globally. This device supports Department of Health and Human Services objectives in the 2010-2015 Strategic Plan to reduce the growth of health care costs while promoting high-value, effective care.