1. Ming-Wei Chen, Sizhu You, Kenneth K. Suslick and Dana D. Dlott 6/17/2014

2. pressure time P “Show Highlights Science Behind Bat and Ball Collisions”, http://www.uml.edu/News/stories/2008- 09/batlab_discovery_show.aspx http://baseball.physics.illinois.edu/ courtesy, Champaign News-Gazette and photographer Robin Scholtz, 2003

3. From a cold hammer to a fireball: How does it happen? Cold EM Mechanical Energy (Shock, impact, friction) Warm EM Without Energy Concentration process No detonation With Energy Concentration process Exothermic process Local heating http://www.bbc.co.uk/news/science-environment-11485672 Mechanical Energy Chemical Energy

4.  Sensor type: mercury cadmium telluride (MCT, >90% quantum efficiency)  Spectral response range: 3.7-4.8 µm.  Spatial resolution: <20 µm.  Frame speed: up to 120fps. “Telescope orientation”“Microscope orientation” High-speed MWIR camera objective lenses Object PC

5. Objective lens High-speed MWIR camera sample glass Al film glued on glass spacer salt window 1064nm laser 8Al·MoO 3 500μm

6. VisibleNIRSWIRMWIR Spectral response region of MWIR camera

7. IR image before experiment Thermal image taken during 200ns after impact 300K 717K Salt window only 500μm 300K 729K

8. 300K 745K IR image before experiment Thermal image taken during 200ns after impact 300K 734K 500μm

9. 300K 685K IR image before experiment Thermal image taken during 500ns after impact 500μm Thickness ~100 μm

10. 300K 685K IR image before experiment Thermal image taken during 500ns after impact 500μm Thickness ~100 μm

11.  Summary  Direct detection of hot spot initiated by shock impact appearing at around the location of energetic particles has been demonstrated.  Small explosive simulant (1-2mm dia. cross section) has been produced with ~100μm thickness, and tested with the experimental apparatus.  Temperature rising rate is about the order of 10 9 K/s within 200ns after impact.  Future Works  Better thin sample preparation and fabrication procedure will be needed.  Experiments with different composite materials, such as PBS, PBX. Varying the size and density of particles to discover the energy localization under shock compression.

12. Dr. Dana D. Dlott Dr. Kenneth S. Suslick The Dlott research group The Suslick research group Funding: –Office of Naval Research –Defense Threat Reduction Agency –National Science Foundation

13. ∆H rxn > H dissipation Growing hot spot (causes detonation) ∆H rxn < H dissipation Dying hot spot (no rxn or gradual burning) Computed critical conditions for hot spot growth in HMX and TATB go no go Tarver, C. M.; Chidester, S. K.; Nichols, A. L., J. P. Chem., 100, 5794 (1996).

14. The spectral response region of our IR-camera is 3.7-4.8 μm, s o that the in- band spectral photon radiance of black body at 300K~ 2.78E19 photon/s/m 2 /steradian. Calculation of in-band spectral photon radiance for black body: Planck’s Law: In-band photon radiance: ν 1 =2083 cm -1 ν 2 =2703 cm -1

15. Fit with equation: Temp. = a * (ratio) b + c High-speed MCT MIR camera f/2.0 objective lenses thermocouple Temp. ctrl. & read heater sample

16. PDV glass Al film glued on glass 1064nm laser spacer window

17. K. T. Sullivan, et. Al, Combust. Sci. and Tech., 183, 285 (2011) 0µs 10µs 20µs 30µs 40µs 50µs 60µs 10.8mm Thermite:  Exothermic oxidation-reduction reaction after ignited.  Widely used in exothermic welding to join materials such as rail road tracks.  8Al·MoO 3.  Particle size distribution: 0.5-50 µm. 100µm Al·AgIO 3

18. 300K 753K IR image before experiment Thermal image taken during impact 300K 745K

19. 300K 745K IR image before experiment Thermal image taken during impact 300K 737K 500μm

20. 300K 685K IR image before experiment Thermal image taken during 500ns after impact 500μm