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Full-Text Articles in Mechanical Engineering

Cellulose–Hemicellulose And Cellulose–Lignin Interactions During Fast Pyrolysis, Jing Zhang, Yong S. Choi, Chang G. Yoo, Tae H. Kim, Robert C. Brown, Brent H. Shanks Jun 2017

Cellulose–Hemicellulose And Cellulose–Lignin Interactions During Fast Pyrolysis, Jing Zhang, Yong S. Choi, Chang G. Yoo, Tae H. Kim, Robert C. Brown, Brent H. Shanks

Brent H. Shanks

Previously, the primary product distribution resulting from fast pyrolysis of cellulose, hemicellulose, and lignin was quantified. This study extends the analysis to the examinations of interactions between cellulose–hemicellulose and cellulose–lignin, which were determined by comparing the pyrolysis products from their native mixture, physical mixture, and superposition of individual components. Negligible interactions were found for both binary physical mixtures. For the native cellulose–hemicellulose mixture, no significant interaction was identified either. In the case of the native cellulose–lignin mixture, herbaceous biomass exhibited an apparent interaction, represented by diminished yield of levoglucosan and enhanced yield of low molecular weight ...


Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen Dec 2010

Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen

Antti Lempinen

No abstract provided.


Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel Dec 2007

Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel

Olivier Doutres Ph.D.

A straightforward criterion for determining the validity of the limp model validity for porous materials is addressed here. The limp model is an “equivalent fluid” model which gives a better description of porous behavior than the well known “rigid frame” model. It is derived from the poroelastic Biot model, assuming that the frame has no bulk stiffness. A criterion is proposed for identifying the porous materials for which the limp model can be used. It relies on a new parameter, the Frame Stiffness Influence FSI, based on porous material properties. The critical values of FSI under which the limp model ...


[Ph.D.] Caractérisation Mécanique De Matériaux Fibreux En Vibro-Acoustique, Olivier Doutres Ph.D. Aug 2007

[Ph.D.] Caractérisation Mécanique De Matériaux Fibreux En Vibro-Acoustique, Olivier Doutres Ph.D.

Olivier Doutres Ph.D.

This work deals with modelization and characterization of the mechanical properties of soft fibrous materials used in aeronautic industries. First, the Biot-Allard model and a simplified model dedicated to soft materials are presented. The simplified model, called limp model, assumes that the frame has no bulk stiffness. Being an equivalent fluid model accounting for the the motion of the frame, it has fewer limitations than the usual equivalent fluid model assuming a rigid frame. A criterion is proposed to identify the porous materials for which the limp model can be used : the use of the Biot model is generally recommended ...


Design And Characteristics Of A Split Hopkinson Pressure Bar Apparatus, Radek Glaser, Jesse Haines, Christopher Knight May 2007

Design And Characteristics Of A Split Hopkinson Pressure Bar Apparatus, Radek Glaser, Jesse Haines, Christopher Knight

Radek Glaser

A Split Hopkinson Pressure Bar Apparatus, also known as Kolsky Bar that is capable of conducting compressive strain rate testing in the approximate ranges from 50 to 10^4 in/in per second was designed as a part of a Senior Design Project. Generally, this device is similar to that first used by Kolsky in 1949. The design of this device is presented here in two stages: 1. Research, design and manufacturing of the Stress Generating System 2. Experimental Part – Testing of the apparatus to obtain necessary data. The present phase of the design was focused mostly on the stress ...