Seminar Schedule

Next Seminar: February 15, 2013, 4:00pm Fu Room (POTR 234).  All LORRE graduate students are expected to attend.

Modeling of Cross-Flow Microfiltration of Aqueous Chicken Homogenates in Hollow Fiber Membrane Module

Xuan Li

Abstract

A mathematical model for constant flux cross-flow microfiltration of aqueous chicken homogenates using hollow fiber membranes is developed by combining Hagen-Poiseuille equation, Darcy’s law and the growth of the film which is formed by the deposited particles and macromolecules on the membrane surface. In the microfiltration of aqueous chicken homogenates, the large particles, viable cells, cell debris and proteins (Ø> 0.2 µm or > 65 kD) and the aggregates of small molecule proteins which are formed by self-association due to the conditions needed to maintain bacterial viability (pH and ionic strength of the chicken homogenates) tend to form a film on the membrane surface at the linear velocities associated with the cross-flow microfiltration. The film reduces the permeability of the membrane, and thus under a constant flux mode causes the rise of transmembrane pressure. The film resistance is directly correlated to the deposit of suspended particles and macromolecules on the membrane surface. The deposition is the net result of permeation towards the membrane and the back transport to the bulk phase. The model is solved numerically to simulate and predict the dependences of permeate flux, film thickness and transmembrane pressure on fiber axial coordinate and filtration time. The model is expected to provide new insights into the performance of the hollow fiber membranes in filtrating food derived fluids containing complex components. The developed model will also be used to identify the relationship between the fouling and filtration conditions and membrane geometry.

Schedule for The Spring Semester

Date	Location	Seminar
January 18	Fu Room	Titles and Abstracts
February 1	Fu Room	Isaac Emery
February 15	Fu Room	Xuan Li
March 1	To be determined	Chia-Ling Wu
March 29	Fu Room	Arun Athmanathan
April 12	Fu Room	Mahdieh Aghazadeh
April 26	Fu Room	Barron Hewetson

Upcoming Events

Poster Symposium

On Friday, March 1st the ABE department will be hosting an event for strong prospective students who will be visiting for the weekend and getting acquainted with ABE. As part of the weekend of events, we will be holding a short Poster Symposium where the prospective students and faculty will be able to interact with and learn about some of the current or recently completed research in our department. If you have work in progress that is ready to be shared, or have previously completed a portion of your research, we need you! Creating and sharing a poster is a great experience not only for your own professional development but also to network with others in the department. Plus, you will have the opportunity to make an impact on the prospective students' impressions of the department and hopefully help them choose Purdue ABE!

If you are willing to participate, please fill out this survey by February 22nd. If you have any questions, feel free to contact Carl Littrell - clittrel@purdue.edu or Dr. Abby Engelberth aengelbe@purdue.edu.

Thank you for your willingness to contribute to ABE and to your own personal development!

Seminar Announcement

“Molecular mechanism of cellulose deconstruction during pretreatment of biomass”

Professor Lee Makowski, Professor of Department of Electrical & Computer Engineering, Northeastern University in Boston

Thursday, February 21st

11am-12pm

Burton Morgan Center,

room 129

Abstract: Lignocellulosic composite in corn stover is a candidate biofuel feedstock of substantial abundance and sustainability. Its utilization is hampered by the recalcitrant nature of the constituent cellulose fibrils to deconstruction. Structural studies (SAXS; WAXS; XFM; SEM) of pretreated corn stover over length scales from microns to Ångstroms indicate that cellulose fibrils follow one of two pathways during pretreatment: (i) Disintegration through the slippage of molecular sheets in the crystalline cellulose fibrils generates amorphous fragments with sufficient flexibility that their glycosidic bonds become susceptible to hydrolytic attack. (ii) Twisting of intact fibrils released from the cell wall matrix by cleavage of hemicellulosic cross-links. Significantly, the twisted fibrils cannot undergo the planar slippage that appears to be an obligate first step in deconstruction suggesting they represent a highly recalcitrant population that exhibits substantial resistance to further digestion.