A Theoretical Model of a Molecular-Motor-Powered Pump

The motion of a cylindrical bead in a fluid contained within a two-dimensional channel is investigated using the boundary element method as a model of a biomolecular-motor-powered microfluidics pump. The novelty of the pump lies in the use of motor proteins (kinesin) to power the bead motion and the few moving parts comprising the pump. The performance and feasibility of this pump design is investigated using two model geometries: a straight channel, and a curved channel with two concentric circular walls. In the straight channel geometry, it is shown that increasing the bead radius relative to the channel width, increases the flow rate at the expense of increasing the force the kinesins must generate in order to move the bead. Pump efficiency is generally higher for larger bead radii, and larger beads can support higher imposed loads. In the circular channel geometry, it is shown that bead rotation modifies the force required to move the bead and that shifting the bead inward slightly reduces the required force. Bead rotation has a minimal effect on flow rate. Recirculation regions, which can develop between the bead and the channel walls, influence the stresses and force on the bead. These results suggest this pump design is feasible, and the kinesin molecules provide sufficient force to deliver pico- to atto- l/s flows.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44478/1/10544_2005_Article_6168.pd

A parametric study of ethylene-fueled scramjet combustion

Ignition-delay distances for ethylene fuel injected into a supersonic combustor are modeled for jet-in-crossflow and shear-layer fuel-injection schemes using analytical models for entrainment and mixing, coupled with detailed chemical-kinetics simulations. Ignition delay distances are calculated for a two-dimensional parameter space of assumed vehicle flight Mach number and fuel-preheat stagnation temperature. The sensitivity of the ignition delays to these parameters is compared and discussed for the two fuel-injection schemes

Microscale Zeta Potential Evaluation Using Streaming Current Measurements

We present a method for determination of zeta potential in capillaries and microscale devices. The use of streaming current measurements under pressure eliminates the need for high voltage measurements while providing a relatively simple means of approximating the zeta potential. This technique finds application in evaluation of coatings as well as materials for separations media and electrokinetic pumping. We will discuss the theory, in which sample porosity and tortuosity information are not required, and we will present zeta potentials of some organic and inorganic media

A Method to Compute Flameout Limits of Scramjet-Powered Hypersonic Vehicles

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140540/1/6.2015-3749.pd

Development of {micro}Chemlab{sup TM}/CG for Detection of Biotoxins

The authors have developed a research prototype device for low level detection of SEB, ricin, botulinum toxin and ovalbumin in liquid samples. This hand-held, low power device analyzes samples by capillary zone electrophoresis (CZE) and capillary gel electrophoresis (CGE) in a parallel microchannel format, and provides sensitive detection of fluorescently-tagged analytes using miniature 392 nm diode laser-induced fluorescence. They have successfully demonstrated simultaneous parallel channel separations, fully automated high voltage control of fluidics and automated data analysis with toxin identification and semi-quantitation in the presence of aerosol backgrounds in a stand-alone self-contained unit. Tests of the fully integrated device indicate high sensitivity detection (as low as 5 nM) and cycle times of 5-10 minutes

A Method to Compute Flameout Limits of Scramjet-Powered Hypersonic Vehicles

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140566/1/6.2016-0914.pd

Biomolecular motors as novel prime movers for microTAS: Microfabrication and material issue

Biomolecular motors that have high efficiency and can generate substantial forces per motor but are truly nanoscopic are promising movers for microTAS. We demonstrate the feasibility of achieving unidirectional motion of microtubules though a microfluidic channel and concentrating microtubules and also describe an incompatibility between a commonly-used material (PDMS) and the motility of labeled microtubules