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Full-Text Articles in Mechanical Engineering

A Quadrature-Based Kinetic Model For Dilute Non-Isothermal Granular Flows, Alberto Passalacqua, Janine E. Galvin, Prakash Vedula, Christine M. Hrenya, Rodney O. Fox Jul 2011

A Quadrature-Based Kinetic Model For Dilute Non-Isothermal Granular Flows, Alberto Passalacqua, Janine E. Galvin, Prakash Vedula, Christine M. Hrenya, Rodney O. Fox

Chemical and Biological Engineering Publications

A moment method with closures based on Gaussian quadrature formulas is proposed to solve the Boltzmann kinetic equation with a hard-sphere collision kernel for mono-dispersed particles. Different orders of accuracy in terms of the moments of the velocity distribution function are considered, accounting for moments up to seventh order. Quadrature-based closures for four different models for inelastic collisionthe Bhatnagar-Gross-Krook, ES-BGK, the Maxwell model for hard-sphere collisions, and the full Boltzmann hard-sphere collision integral-are derived and compared. The approach is validated studying a dilute non-isothermal granular flow of inelastic particles between two stationary Maxwellian walls. Results obtained from the kinetic models ...


Steam Reforming Of Bio-Oil Fractions: Effect Of Composition And Stability, Pedro J, Ortiz-Toral, Justinus A. Satrio, Robert C. Brown, Brent H. Shanks Jan 2011

Steam Reforming Of Bio-Oil Fractions: Effect Of Composition And Stability, Pedro J, Ortiz-Toral, Justinus A. Satrio, Robert C. Brown, Brent H. Shanks

Chemical and Biological Engineering Publications

The efficacy of steam reforming of the aqueous species in bio-oils produced from the fast pyrolysis of biomass is examined. A fractionating condenser system was used to collect a set of fractions of fast pyrolysis liquids with different chemical characteristics. The water-soluble components from the different fractions were steam-reformed using a nickel-based commercial catalyst in a fixed-bed reactor system. When reforming at 500 °C, an overall positive effect in hydrogen yields was observed for the fractions with higher concentrations of lower molecular-weight oxygenates, such as acetic acid and acetol, while the heavier compounds, such as the carbohydrates, showed an ...


Confocal Imaging Of Laminar And Turbulent Mixing In A Microscale Multi-Inlet Vortex Nanoprecipitation Reactor, Yanxiang Shi, Rodney O. Fox, Michael G. Olsen Jan 2011

Confocal Imaging Of Laminar And Turbulent Mixing In A Microscale Multi-Inlet Vortex Nanoprecipitation Reactor, Yanxiang Shi, Rodney O. Fox, Michael G. Olsen

Chemical and Biological Engineering Publications

Mass production of functional nanoparticles may be realized through flash nanoprecipiation in microscale reactors such as the multi-inlet vortex reactor (MIVR). A comprehensive understanding of mixing in the MIVR is required for process control and reactor design. Mixing in the MIVR is studied using a technique coupling laser induced fluorescence with confocal laser scanning microscopy. It is shown to provide meaningful qualitative and statistical data of the scalar field for analysis and comparison with numerical simulations. Data were collected for four flow rates, showing that mixing is incomplete even at the highest flow rate.


Hybrid Thermochemical Processing: Fermentation Of Pyrolysis-Derived Bio-Oil, Laura R. Jarboe, Zhiyou Wen, Dong Won Choi, Robert C. Brown Jan 2011

Hybrid Thermochemical Processing: Fermentation Of Pyrolysis-Derived Bio-Oil, Laura R. Jarboe, Zhiyou Wen, Dong Won Choi, Robert C. Brown

Chemical and Biological Engineering Publications

Thermochemical processing of biomass by fast pyrolysis provides a nonenzymatic route for depolymerization of biomass into sugars that can be used for the biological production of fuels and chemicals. Fermentative utilization of this bio-oil faces two formidable challenges. First is the fact that most bio-oil-associated sugars are present in the anhydrous form. Metabolic engineering has enabled utilization of the main anhydrosugar, levoglucosan, in workhorse biocatalysts. The second challenge is the fact that bio-oil is rich in microbial inhibitors. Collection of bio-oil in distinct fractions, detoxification of bio-oil prior to fermentation, and increased robustness of the biocatalyst have all proven effective ...