Dynamic Behavior of Earth Materials Subjected to Pressure-Shear Loading

Dr. John Borg, Prof. of Mechanical Engineering, Marquette University

The dynamic behavior of earth materials, such as wet and dry sand, is of interest to a variety of research fields such as defense, mining and planetary science. Plane-strain experiments are necessary to obtain the Hugoniot response of such systems however such loading is not indicative of most loading scenarios of interest.  Thus understanding oblique impact configuration (pressure-shear) can lead to a better understanding of the role of strength in the dynamic response of earth materials.  Figure 1 illustrates the basic configuration of the impact experiment and sand of interest.  A key aspect of this experiment is obtaining an accurate measurement of the normal and transverse velocity of the anvil.  For these experiments a photon Doppler velocimetry (PDV) will be used.  The configuration and the inherent difficulties of applying such a diagnostic technique to this experiment will be discussed.

Seminar will be held at 3:30 PM in Malone G33/35.

Fig. 1. (a) Oblique impact configuration with assembly with a thin sand sample with incident and reflected probes (b) Oklahoma #1 pure sand (425 – 500 μm diameter)

“Digitally Based Micro Manufacturing”

Presented by Mike Adelstein Potomac Photonics, 1450 South Rolling Road, Baltimore, MD 21117

In the rapidly changing landscape of technology there is a fast growing movement toward micro- manufacturing that spans industries such as electronics, biotech, medical, and energy. As market demand for miniaturization increases at a seemingly exponential rate it is critical that solutions be provided for these industries that help them overcome barriers to micro manufacturing. These include accessibility, cost, and technical knowledge, all of which can prevent investigators from developing new micro products.

Potomac Photonics is a micro machine foundry that provides immediate access to high-tech micro machining capabilities. Since no one technology prevails when developing micro products, Potomac Photonics has a “tool box” of technologies such as laser-machining, 3D printing, micro-CNC, pick and place and hot embossing and more. Potomac Photonics concept goes beyond simple electronic commerce by expanding virtual access to a suite of technologies and allowing collaboration with skilled and experienced micro fabrication experts capable of manufacturing extremely complex micro devices.

Mike Adelstein has set Potomac Photonics on a course for leading the Next Industrial Revolution by expanding Potomac’s groundbreaking contract manufacturing focus to include expanded capabilities such as 3D Printing and new combinations of Digital Fabrication technologies. He has successfully entered partnerships with leading medical, biotech, consumer goods, and automotive companies and also spearheaded the Company’s Education Initiative to work with leading universities and institutes on fundamental R&D. Mr. Adelstein led the company’s movement toward the ISO9001:2008 and 13485:2003 quality designations, and in 2014 set up a showcase Digital Fabrication center at the bwtech@umbc Research and Development center.

Prior to joining Potomac in 1997 he spent time at the National Institutes of Health and two years at Haven Corporation, a chemical adhesives company, leaving as a Chemist. A graduate of the University of Maryland, Baltimore County with a degree in Biochemistry and Molecular Biology, Mike Adelstein also has a MS in Technology Management and is a Certified Public Account (CPA).

HEMI and the Mechanical Engineering Department are pleased to present “Music by the Numbers: an Attempt to Understand Why Certain Musical Chords Sound Better than Others,” a special lecture given by Professor Marc de Graef of the Department of Materials Science and Engineering at Carnegie Mellon University.

Please see details below and make sure to RSVP to Bess Bieluczyk at bess@jhu.edu by close of business on Wednesday, November 12th to reserve your spot!