Day: November 26, 2014

The Earth, Planetary, and Space Sciences Institute
proudly presents:
Ezequiel Medici, MTU ME-EM Research Engineer
The EPSSI seminar for Monday, December 1, 4:00 p.m., M&M U113

“Shock Tube Recreations of Shock Waves and Jets Generated During Explosive Volcanic Eruptions”

Abstract: At the beginning of a suddenly explosive volcanic eruptions two types of phenomena can be observed, the formation of a shock wave immediately followed by a supersonic jet of expanding vapor-solid-liquid mixture. The intensity of the shock wave and the structure of the supersonic jet can carry a significant amount of information about the intensity and the dynamics of the volcanic eruption. Despite the hazard they represent to the immediate surrounding area of the volcano vent, these atmospheric shock waves and the subsequent sonic wave can be safely measured at a long distance from the vent. This characteristic makes the measurement of shock/sonic waves suitable for safe, real-time remote sensing of the conditions at the volcanic vent during the eruption. Preliminary results, based on the experiment performed on the shock tube, indicate a strong correlation between the energy released by the eruption, calculated by standard methods post eruption, and the intensity of the shock wave as measured through its pressure field. This correlation could ultimately lead to a more reliable model of shock/sound wave propagation which will serve as an early warning system for the air traffic control.

Immediately after the shock wave, an over pressurized jet mixture of vapor, solid particles, and liquid begins to expand. This mixture typically contains a relatively high concentration of solid particles of different size. To study the coupled interaction between the expanding gas and the particles, a series of analog explosive volcanic experiments using the atmospheric shock tube were performed. High-speed shadowgraph imaging of the expanding jet mixtures is recorded for different initial jet energy, particle sizes and particle concentrations. The study and observations of the interaction between the mixture of expanding gas and particles can elucidate the mechanisms acting during the initial stage of the formation of ash plumes or pyroclastic flows.

Environmental Engineering Graduate Seminar: Monday, December 1, 2014, 3-4 PM, GLRC 202, Public Welcome
Speaker: Dr. Caryn L. Heldt
Title: Virus Removal from Water and Bioterapeutics

The removal of viruses can save millions of lives through the creation of safe drinking water and reducing the cost of biotherapeutic production to increase access to live saving drugs. In order to create more robust virus removal methods, we need to better understand the surface characteristics of viruses. The most well-known surface characteristic of viruses is negative charge. To take advantage of this, we created filtration membranes with a positively charged polymer. An ideal virus removal membrane would have low transmembrane pressure, high water flux, high pathogen removal, and have a long, workable lifetime. To provide these qualities, we created a nanofiber filtration material that has a microporous structure for high water flux and low transmembrane pressure. Viruses adsorbed to the high surface area nanofibers through electrostatic interactions for virus removal. A lesser-known surface characteristic of viruses is hydrophobicity. We have evidence that viruses are hydrophobic and therefore, we have explored novel flocculants for virus removal that take advantage of virus hydrophobicity. We have been able to remove two viruses with theses flocculants, and we continue to explore the effect of other viruses in our flocculant system. The flocculant system is more applicable to the removal of viruses from biotherapeutics, but other flocculants, based on hydrophobicity and are less expensive, could be applied to water treatment.