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Particle Processing Research

Particle Processing Research. Terry A. Ring Chemical Engineering University of Utah. Presentation Goals. Introduce My Work to NSF Show Breadth of Coverage Fundamentals of Ceramic Powder Processing and Synthesis Product Box Show Depth of Coverage in One Area Nano-sized Cluster Nucleation

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Particle Processing Research

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  1. Particle Processing Research Terry A. Ring Chemical Engineering University of Utah

  2. Presentation Goals • Introduce My Work to NSF • Show Breadth of Coverage • Fundamentals of Ceramic Powder Processing and Synthesis • Product Box • Show Depth of Coverage in One Area • Nano-sized Cluster Nucleation • NSF - Program Vision

  3. Crystallization Inhibitors - Trane Corp. Nifedipine (Heart Drug) Sintering-Pfizer, Bayer Scaling Chemicals-Spa Natural Bio-Cements as Bone Replacement Materials - Sultzer, Mathis Ceramic Thin Films As Chemical Sensors - RMA Associates BaTiO3 Multi-layer Capacitors- Phillips(Taiwan) Ceramic Particle Processing Research

  4. Multi-layer Chip Support Sintering - Metalor, IBM, Dupont Vermiculite Based Insulation Materials - ABB Silica Aerogels for Building Insulation - Airglass, SA Nitride coating for Al2O3 Platelets for Cutting Tools - Amysa, SA Pultrusion Process for Carbon Fiber Reinforced Composite - Easton Ceramic Particle Processing Research-con’t

  5. Precipitation Research

  6. Agglomeration in CSTR

  7. Nano-sized Cluster Nucleation • Introduction • Classical Nucleation Theory & Limitations • New Theory & Findings

  8. Silicon Particles Introduction • Unique Properties of Nanosized Particles • Plasmon Resonance -color due to size, color change due to adsorption-sensors • Between Bulk and Atomic Electrical Properties • Catalytic Properties • Magic Cluster Sizes • C60, C70, C nanotubes, • Na clusters of 8, 20, 40, 58 and 92

  9. Stimulated Emission CdS Nano-Clusters-Laser • Lasing only when quantum dot concentration is sufficiently high. • Stimulated emission>Auger recombination • Klimov, V. Mikhailovsky, A.,Xu, S., Hollingswork, J., Malko, A., Bawendi, M., Eiser, H-J., Leatherhead, C.A. • Science 290,314 (2000) • Science 287,1011 (2000)

  10. 800 700 MoS Photocatalyst 2 600 500 t=1 hour 400 Absorbance (250 nm) 300 200 alkyl chloride 100 t = 0 0 3 4 5 6 7 8 Elution Time (min) Semiconductor Nanocrystals Breakdown Organic Pollutants 3 nm MoS2 nanocrystals photo-oxidizean alkyl chloride in solution using only visible room light • Environmental remediation • Solar photocatalysis/fuel production

  11. Fullerene Synthesis

  12. Fullerene Synthesis odd vs. even clusters

  13. Nanoparticle Synthesis Desperate Need to Control and Scale-up!!

  14. Nanoparticle Synthesis = Nucleation (no Growth!!) • Classical Nucleation Theory • Free Energy in two piecesG(r) = -(bv r3/Vm)RT ln(S)+ gba r2 G(i) = - i kBT lnS+ g ba ao2i2/3 where v(=bvr3) is the volume and a(=bar2) is the area of the aggregate,is the molar volume of the precipitate, g is the surface free energy per unit area. • X(atom) +X(r*-atom)<----> X(r*) G(i) S Critical Size, r*

  15. New Nucleation Theory • Multi-Atom Addition • Free Energy Driving Force for Diffusion and Addition • New Attributes • Predicts transients of Cluster Size Distribution • Predicts Induction Time

  16. Population Balance - Multi-atom Addition • Numerical solution required except • lij = 1 Ck = • Smoluchowski, Physik Zeits, 17,557(1916) • lij= i+j Ck = , u= 1-exp(-t) • Scott, W.T., J. Atmos. Sci., 25,54(1968) • lij=i*j Ck = tk-1 kk-2 exp(-k t)/k!, t  0 • McLeod, J.B., Quant, J. Math Oxford, 13,119 and 193(1962).

  17. Collision Frequency

  18. Collision Free Energy, Gij • Gij =G(i+j)-(G(i)+G(j)) • G(i) = - i kBT lnS + g ba ao2i2/3 • i or j > 1 • Gij =G(i+j)-(G(i)+G(j))=g ba ao2 [(i+j)2/3 - i2/3 - j2/3] • i = 1, any j • Gij = - i kBT lnS + g ba ao2 [(i+j)2/3 - j2/3 ] • j = 1, any i • Gij = - j kBT lnS + g ba ao2 [(i+j)2/3 - i2/3 ]

  19. Effect of exp(-Gij/kBT) on Nucleation • lij=(i+j)exp(-Gij/kBT), • Numerical Solution- C • lij=(i+j), • Analytical Solution, N

  20. Binding Energy per Li atom Kouteckky, J. and Fantucci, P., Chem. Rev., 86,539-87(1986).

  21. Cluster Binding Energy

  22. Activation Energy for i+j Cluster

  23. Structural Classical

  24. New Nucleation Theory • Dramatic effect for stable clusters, k=2,4,8,…  Magic Clusters • Magic Clusters Affects Synthesis Path • Not One but Multiple Critical Cluster Sizes • Nucleation Rate, I= dCk*/dt • Depends on Synthesis Path

  25. Crystalloluminescence

  26. Crystalloluminesent Spectrum • Intensity vs Energy • Intensity = collisions/per unit time = photons/unit time • Wavelength E = hc/l • Human eye detection @ 3x104photons/cm2/s at λ 510 nm Wavelength(nm) 2480 1240 827 620 496

  27. Similar to Line Spectra

  28. Is this another cold fusion? • An effect produced by a barely detectable cause. • Data on the edge of detectability • Measurements are attributed to greater accuracy • Fantastic theories are offered. • Criticisms are met by ad hoc excuses thought up on the spur of the moment. • The ratio of supporters to critics rises up to ~50% and then falls gradually to oblivion. From1953 Lecture by Irving Langmuir

  29. Another cold fusion? Cont. • Researcher avoids designing experiments that would confirm whether or not an effect actually exists. (D. Rousseau, 1982). • Pressures to publish prematurely (Broad, W. and Wade, N., 1982.) • Being scooped. • Notoriety. • Potential for money to be made. • More common in fields with reliance on statistically weak data. (N. Turro, 2001)

  30. Crystalloluminescence • Term Schoenwald in 1786 • 30 References 1786 and 1957 • “An understanding of crystalloluminescence in not too satisfactory at the present time,” E.N. Harvey 1957 • Examples: NaCl, KCl, NaF, AsCl3, K2SO4, As3O3, Sr(NO3)2,, CoSO4, K2CO3, KHSO3, NaKSO4, NaKCrO4, NaKSeO4, Na2SO4, benzoic acid, and ice, water. • 16 References 1957-1991 (15 Russian,1 US+ 1 Italian Review) • “It is not possible to … provide either a unifying physical picture of the microscopic mechanism governing (crystalloluminescence) or a physical rule that allows conditions...where the phenomenon is stronger,” Barsanti, M. & Maccarrone,F., 1991 • 3 References from 1991-2000 (2 India, 1 Russian) - Experiments

  31. Experimental Observations • Delay time is a function of concentration & mixing • Flashes are Short • < 80 ns • Peak Count rates • ~5-8x105 photons/s • Temporal & Spatial Bunching of Flashes • 340nm<λ<380 nm • Faint Blue White Light Saturated NaCl + Conc. HCl - 120 s observation time Gibbon, M.A., Sopp, H. , Swanson, J., and Walton, A.J., J. Phys. C. 21,1921(1988).

  32. Spectra Has Series of Peaks • Lines are Different from • Thermal Luminescence • Photoluminescence • Impurities in Crystal have a Big Effect on Spectrum BaSO4 Crystallization (20 min. exposure) Lines 1935Å-1945Å 1976Å-1991Å 2021Å-2037Å 2145Å-2165Å 2228Å-2300Å 2300Å-2326Å Rabinerson, A.I. Wladimirskaya, M.A., Acta Physicochimica URSS, 10,859(1939)

  33. New Theory’s Predictions • Predicts Crystalloluminescent Spectrum • Method to Quantitatively Measure Nucleation • Potential Real World Examples • H2O Condensation Nucleation • Interstellar Dust Nano-nucleation • Light from Deep Sea Vents

  34. Super Novae

  35. Experimental Verification Nanocluster, Ti14C13 with emission peak at 20.1 microns is seen in Egg Nebula by A.G.G.M. Thielens and M.A. Duncan Science 288,313(2000) this joins some 120 other small molecules identified in the vicinity of stars, interstellar gas and dust clouds

  36. Interstellar Dust Clouds - Light from the Fringe - Crystalloluminescence due to Nanocluster Nucleation

  37. NSF • Particulate and Multiphase Program • 1. Aerosols and colloids • 2. Nanostructures • 3. Granular flows • 4. Multiphase processes related to particles, droplets, and bubbles • 5. Hydrodynamical multiphase analysis • 6. Specific tools

  38. Nanotechnology has acquired National Status • National Nanotechnology Initiative $500M proposedfor FY01 Federal Budget • Usher in the “Next Industrial Revolution” • Develop and explore the “rules and tools” of nanotechnology • Education and SocietalImplications President Clinton’s Jan. 21, 2000 announcement of a “National Nanotechnology Initiative” in a speech from the California Instituteof Technology.

  39. Nanoscience -- behavior of materials at the nanoscale isNothing like that at the large scale Light from Si • Properties not predictable from those at large scale • Different physics and chemistry emerges • New phenomena associate with: Catalysis from Pd clusters • Electronic confinement • Preponderance of surfaces and interfaces • Quantized effects Pyrene hydrogenation GPa strength from Au Lead to: Measured Yield Point • New modes of electronic and thermal transport • Different manifestations of thermodynamic properties, phase transitions, and collective phenomena • New chemical reactivities • New mechanical properties--strength, friction, wear

  40. Many Particulate Problems in Nanotechnology • Lasers, Catalysis • Photonic Crystals - optical computing • Photonic Light Pipes • Nano TiO2 Solar Cells • Nanotubes - computer wires, transistors • Nanotube Light Emission - Displays • Nanocomposites - tunable lasers

  41. Layered Structures • Taylored Materials • Electronics/photonics • Novel Magnets • Tailored hardness

  42. Defects in Ordered Arrays Bend Light Optical Semiconductors

  43. Hexagonal Packing of Spheres • Light Diffraction

  44. Photonic Crystal Light Pipe Light Leaving Pipe Light Pipe

  45. poly-Si Si substrate Quantum Computing- Light Traps Stopping Light without Absorption Yablonovitch, E., 1986.

  46. Coupling to Biology • Sol-gel (or Micelle structures) for drug delivery • Diffusive Collisions ~ R(DF+2-3) • Diffusing Species will Stay in Fractal when DF >1.0 Barbe, C., 2001 Australian Patent Application

  47. Connection to Biology • Enzyme Binding • Surfaces • Particles • Better BioCatalysis • Protein Binding • Surfaces • Particles • Better Implants 1/4th of Catalyase Tetramer Heam Site Liver Enzyme 2 H2O2 ----> 2 H2O + O2(g)

  48. Nano-particles for • Bio Separations/Bio Sensing

  49. Couple to Computation • Nanoparticle properties from Computational QM • Particulate Generation in CFD • Molecular Adsorption • Molecular Binding • Fractals + Flow

  50. Conclusion • Particulate and Multiphase Program • Bright Future • Many New Research Areas • Many New Phenomena • Collaboration is key to Success • Virtual Centers • Nano Property Prediction • Photonic Crystals • Enzyme/Particle Binding • Fractal Aggregates • Nano Particle Synthesis

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