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Sun, XinyuFault Modeling and Fault Type Distinguishing Test Methods for Digital Microfluidics Chips
MS, University of Cincinnati, 2013, Engineering and Applied Science: Computer Engineering
Physical defects in digital microfludics chips (DMCs) can be very complicated and extremely difficult to find precise models, because each defect may occur anywhere. In this thesis, we develop high-level abstract fault models based on investigating the faulty and fault-free behaviors of droplet moving. Two new fault models that were not found previously are proposed to enhance the reliability of DMCs. We believe that the high-level fault models can completely cover all defects involving two cells in a DMC array. Based on the new high-level fault models, we propose march algorithms (march-d and march-p/p+) to generate test patterns that can detect and distinguish fault types for each faulty digital microfludics chip. This is accomplished by merging both march-d and part of march-p without causing too much test length increase. These algorithms are implemented into a FPGA board attached to the simulated digital microfluidics chip such that built-in self-test can be accomplished without human intervention. We also develop an EDA tool and simulation platform for the proposed DMC-BIST system. Experimental results demonstrate that the proposed fault models, test and fault type distinguishing methods, built-in self-test circuit design, and emulation tool can effectively and efficiently achieve high quality test with minimal test cost.

Committee:

Wen Ben Jone, Ph.D. (Committee Chair); Xingguo Xiong, PhD (Committee Member); Ian Papautsky, Ph.D. (Committee Member)

Subjects:

Computer Engineering

Keywords:

Fault modeling;Test methods;BIST;Digital microfluidics chip;Microfluidics EDA;March algorithm

Kohlman, Lee W.Evaluation of Test Methods for Triaxial Braid Composites and the Development of a Large Multiaxial Test Frame for Validation Using Braided Tube Specimens
Doctor of Philosophy, University of Akron, 2012, Civil Engineering
The characterization of carbon/epoxy 2D triaxial braid composites is a critical area of research for aerospace components, including jet engine fan blade containment. These materials exhibit high strength to stiffness, high damage tolerance, and a favorable impact response. This is due, in part, to the material behaving like a structure once damage occurs because of the mechanical interlocking and large unit cell of the fabric architecture. This, in turn, complicates the results and interpretation of coupon based mechanical testing because the desired uniaxial stress state is unavoidably lost within the material after the onset of damage. Though this same process will likely occur in structures, it has been shown in standard coupons that the existence of free edges can lead to premature initiation of local damage that leads to early failure. Therefore, many different methods will be needed to obtain reliable mechanical response data for use in models and structural design. The goal of this research is to attempt to bridge part of the gap between coupon level testing and structural component tests. An in depth examination of tension, compression, and shear coupon test methods for generating stiffness, strength, and non-linear material response parameters has been performed. Additionally, the use of tubular specimens under various load conditions assisted in validation of alternate coupon geometries, as well as evaluating the utility of current cross-ply laminate test standards. Also, damage mechanisms, as they relate to global response, are considered. The particular materials of interest (similar to braid architectures used in jet engine containment structures) have a large unit cell size which requires the use of relatively large tube specimens. To meet the “to failure” load requirements of these specimens, a custom high load, multiaxial test frame was designed, machined, and constructed. Control and data acquisition was achieved using National Instruments cDAQ hardware and custom NI Labview VI’s. The NI Labview control software includes a simple user interface with modules focused on test setup, monitoring, fault alert, and several other features. Development of tube grip fixtures and test specimen design has also been performed.

Committee:

Wieslaw K. Binienda, Dr. (Advisor); Robert Goldberg, Dr. (Committee Member); Craig Menzemer, Dr. (Committee Member); Gregory Morscher, Dr. (Committee Member); Anil Patnaik, Dr. (Committee Member); Sasa Dordevic, Dr. (Committee Member)

Subjects:

Engineering

Keywords:

composite; strength; carbon fiber; test methods; tube; braid; polymer matrix composite

SNYDER, ERIN MARIEDETERMINATION OF KNOWN EXHALATION VALVE LEAKAGE USING THE RESPIFIT TM IRRITANT SMOKE TEST KIT
MS, University of Cincinnati, 2001, Medicine : Environmental Health Sciences
The goal of this study was to evaluate the ability to detect irritant smoke in the presence of a known exhalation valve leak using a RespiFit TM Respirator Qualitative Fit Test Kit. The OSHA protocol for the irritant smoke test mandates the use of a low flow air pump or aspirator squeeze bulb. Many commercial test kits include an aspirator bulb, which is subject to variation from depth of squeeze, fatigue and individual hand strength. The RespiFit TM is designed to prevent these variables by emitting a continuous smoke stream via a battery-operated pump. Twenty subjects wearing North 7600 series full-face respirators equipped with P100 filters were fit tested with a Portacount Plus to ensure adequate fit. The exhalation valve was replaced with a damaged valve and rotated approximately 90° as needed to produce a fit factor below 100. Having induced an exhalation valve leak, the irritant smoke test was performed using the OSHA irritant smoke protocol. The RespiFit TM did not detect 40% of respirators with leaking exhalation valves. Sixty percent of the subjects were able to detect the irritant smoke. Results of the ANSI Draft Z88.10 sensitivity calculation indicate that the irritant smoke test performed with the RespiFit TM did not meet the 95% criterion for identifying an inadequate fit. Of the 12 subjects that failed the smoke test, none detected the smoke in less than a minute; the average detection time was 3:05 minutes. Five subjects who detected the irritant smoke did so after suppressing a reaction. These subjects indicated an ability to ignore the effects of the irritant smoke for a period of time. Only one of the eight subjects who were instructed to break the face to face-piece seal after passing the fit test detected the irritant smoke. The remaining seven subjects did not detect the irritant smoke until given the second sensitivity test. These findings suggest that qualitative fit testing using an irritant smoke fit test with a 200 mL/min continuous flow pump does not have adequate sensitivity and should be substituted with a more sensitive method.

Committee:

Dr. Roy T. McKay (Advisor)

Subjects:

Environmental Sciences

Keywords:

respirator; qualitative fit testing; fit test methods