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Full-Text Articles in Engineering

Manipulation Of Suspended Single Cells By Microfluidics And Optical Tweezers, Nathalie Neve De Mevergnies, Sean S. Kohles, Shelley R. Winn, Derek C. Tretheway Sep 2010

Manipulation Of Suspended Single Cells By Microfluidics And Optical Tweezers, Nathalie Neve De Mevergnies, Sean S. Kohles, Shelley R. Winn, Derek C. Tretheway

Mechanical and Materials Engineering Faculty Publications and Presentations

Chondrocytes and osteoblasts experience multiple stresses in vivo. The optimum mechanical conditions for cell health are not fully understood. This paper describes the optical and microfluidic mechanical manipulation of single suspended cells enabled by the μPIVOT, an integrated micron resolution particle image velocimeter (μPIV) and dual optical tweezers instrument (OT). In this study, we examine the viability and trap stiffness of cartilage cells, identify the maximum fluid-induced stresses possible in uniform and extensional flows, and compare the deformation characteristics of bone and muscle cells. These results indicate cell photodamage of chondrocytes is negligible for at least 20 min for laser …


Developing Sustainable Life Support System Concepts, Evan A. Thomas Jul 2010

Developing Sustainable Life Support System Concepts, Evan A. Thomas

Mechanical and Materials Engineering Faculty Publications and Presentations

Sustainable spacecraft life support concepts may allow the development of more reliable technologies for long-duration space missions. Currently, life support technologies at different levels of development are not well evaluated against each other, and evaluation methods do not account for long-term reliability and sustainability of the hardware. This paper presents point-of-departure Sustainable System Mass (SSM) evaluation criteria for life support systems that may allow more robust technology development, testing, and comparison. An example sustainable water recovery system concept is presented.


Second-Generation International Space Station Total Organic Carbon Analyzer Verification Testing And On-Orbit Performance Results, Nicole L. Bentley, Evan A. Thomas, Michael Van Wie, Chad Morrison Jul 2010

Second-Generation International Space Station Total Organic Carbon Analyzer Verification Testing And On-Orbit Performance Results, Nicole L. Bentley, Evan A. Thomas, Michael Van Wie, Chad Morrison

Mechanical and Materials Engineering Faculty Publications and Presentations

The International Space Station (ISS) total organic carbon analyzer (TOCA) is designed to autonomously assess recovered water quality by providing an indication of total organic carbon (TOC). The current TOCA has been on the ISS since November 2008. Functional checkout and operations revealed complex operating considerations. Specifically, failure of the hydrogen (H2) catalyst resulted in development of an innovative oxidation analysis method. This method reduces activation time and limits the H2 produced during analysis, while retaining the ability to indicate TOC concentrations within 25% accuracy. Subsequent testing and comparison to archived samples returned from the station and tested on the …


Climate And More Sustainable Cities: Climate Information For Improved Planning And Management Of Cities (Producers/Capabilities Perspective), C.S.B. Grimmond, Matthias Roth, Tim R. Oke, Y. C. Au, M. Best, R. Betts, Gregory R. Carmichael, Helen Cleugh, Walter F. Dabberdt, Rohinton Emmanuel, E. Freitas, K. Fortuniak, Steven Hanna, Petra M. Klein, Laurence S. Kalkstein, C. H. Liu, Alex Nickson, David Pearlmutter, David J. Sailor, James Voogt Jan 2010

Climate And More Sustainable Cities: Climate Information For Improved Planning And Management Of Cities (Producers/Capabilities Perspective), C.S.B. Grimmond, Matthias Roth, Tim R. Oke, Y. C. Au, M. Best, R. Betts, Gregory R. Carmichael, Helen Cleugh, Walter F. Dabberdt, Rohinton Emmanuel, E. Freitas, K. Fortuniak, Steven Hanna, Petra M. Klein, Laurence S. Kalkstein, C. H. Liu, Alex Nickson, David Pearlmutter, David J. Sailor, James Voogt

Mechanical and Materials Engineering Faculty Publications and Presentations

In the last two decades substantial advances have been made in the understanding of the scientific basis of urban climates. These are reviewed here with attention to sustainability of cities, applications that use climate information, and scientific understanding in relation to measurements and modelling. Consideration is given from street (micro) scale to neighbourhood (local) to city and region (meso) scale. Those areas where improvements are needed in the next decade to ensure more sustainable cities are identified. High-priority recommendations are made in the following six strategic areas: observations, data, understanding, modelling, tools and education. These include the need for more …


Development Of A Contingency Capillary Wastewater Management Device, Evan A. Thomas Jan 2010

Development Of A Contingency Capillary Wastewater Management Device, Evan A. Thomas

Mechanical and Materials Engineering Faculty Publications and Presentations

The personal body-attached liquid liquidator (PBALL) is conceived as a passive, capillary-driven, contingency wastewater disposal device. In this contingency scenario, the airflow system on the NASA crew exploration vehicle is assumed to have failed, leaving only passive hardware and vacuum vent to dispose of wastewater. To meet these needs, the PBALL was conceived to rely on capillary action and urine wetting conditions from 0° < θadv ∼ 90°, be adaptable for both male and female use, collect and retain up to 1 L of urine, minimize splash-back, and allow continuous draining of the wastewater to vacuum while minimizing cabin air loss. A subscale PBALL test article, which was tested on NASA's reduced-gravity aircraft in April 2010, successfully demonstrated key components of this design.