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- 3-D shape measurement (2)
- Lawrence Berkeley National Laboratory (2)
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Articles 1 - 26 of 26
Full-Text Articles in Physical Sciences and Mathematics
High-Speed Three-Dimensional Shape Measurement System Using A Modified Twoplus- One Phase-Shifting Algorithm, Song Zhang, Shing-Tung Yau
High-Speed Three-Dimensional Shape Measurement System Using A Modified Twoplus- One Phase-Shifting Algorithm, Song Zhang, Shing-Tung Yau
Song Zhang
This paper describes a high-resolution, real-time, three-dimensional shape measurement system using the modified two-plus-one phase-shifting algorithm. The data acquisition speed is as high as 60frames∕s with an image resolution of 640×480pixels per frame. Experiments demonstrated that the system was able to acquire the dynamic changing objects such as facial geometric shape changes when the subject is speaking, and the modified two-plus-one phase-shifting algorithm can further alleviate the error due to motion. Applications of this system include manufacturing, online inspection, medical imaging, compute vision, and computer graphics.
Posterminaries: More Or Less Modern, Alexander H. King
Posterminaries: More Or Less Modern, Alexander H. King
Alexander H. King
It is yet another sign that I am aging. More and more often when young researchers hand me a written report of their research, I find myself criticizing their introductory section: “You need to start your literature survey with the original papers on this topic. Go and read…” followed by a citation to some classic of the learned literature.
Platinum Nanoparticle Shape Effects On Benzene Hydrogenation Selectivity, Kaitlin M. Bratlie, Hyunjoo Lee, Kyriakos Komvopoulos, Peidong Yang, Gabor A. Somorjai
Platinum Nanoparticle Shape Effects On Benzene Hydrogenation Selectivity, Kaitlin M. Bratlie, Hyunjoo Lee, Kyriakos Komvopoulos, Peidong Yang, Gabor A. Somorjai
Kaitlin M. Bratlie
Benzene hydrogenation was investigated in the presence of a surface monolayer consisting of Pt nanoparticles of different shapes (cubic and cuboctahedral) and tetradecyltrimethylammonium bromide (TTAB). Infrared spectroscopy indicated that TTAB binds to the Pt surface through a weak C-HâââPt bond of the alkyl chain. The catalytic selectivity was found to be strongly affected by the nanoparticle shape. Both cyclohexane and cyclohexene product molecules were formed on cuboctahedral nanoparticles, whereas only cyclohexane was produced on cubic nanoparticles. These results are the same as the product selectivities obtained on Pt(111) and Pt(100) single crystals in earlier studies. The apparent activation energy for …
Non-Destructive Horseradish Peroxidase Immobilization In Porous Silica Nanoparticles, Rebecca Voss, Michael A. Brook, Jordan Thompson, Yang Chen, Robert H. Pelton, John D. Brennan
Non-Destructive Horseradish Peroxidase Immobilization In Porous Silica Nanoparticles, Rebecca Voss, Michael A. Brook, Jordan Thompson, Yang Chen, Robert H. Pelton, John D. Brennan
Rebecca Cademartiri
The preparation of protein doped silica particles is impeded by the difficulty of incorporating proteins within the silica mesostructure under conditions that do not lead to denaturation. Herein, the synthesis of spherical silica particles (diameter 150 nm–550 nm) under protein friendly conditions in a one step process is described. Diglyceroxysilane (DGS) was reacted in ethanol and methanol-free conditions in pure water or in buffer solutions with or without the presence of additional glycerol. Stabilization of the particles, consistent with steric stabilization, was obtained using poly(ethylene glycol) (PEG) of various molecular weights and with various end groups, including allyl and (CH2)3Si(OEt)3 …
3d Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau
3d Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau
Song Zhang
Three-dimensional data merging is critical for full-field 3-D shape measurement. 3-D range data patches, acquired either from different sensors or from the same sensor in different viewing angles, have to be merged into a single piece to facilitate future data analysis. In this research, we propose a novel method for 3-D data merging using Holoimage. Similar to the 3-D shape measurement system using a phase-shifting method, Holoimage is a phase-shifting-based computer synthesized fringe image. The virtual projector projects the phase-shifted fringe pattern onto the object, the reflected fringe images are rendered on the screen, and the Holoimage is generated by …
Control Of Porosity In Fluoride Thin Films Prepared By Vapor Deposition, Alexander H. King
Control Of Porosity In Fluoride Thin Films Prepared By Vapor Deposition, Alexander H. King
Alexander H. King
We have measured the porosity in thin films of lithium fluoride (LiF), magnesium fluoride (MgF2), barium fluoride (BaF2), and calcium fluoride (CaF2) as a function of the substrate temperature for films deposited by thermal evaporation onto glass substrates. The amount of porosity in the thin films was measured using an atomic force microscope and a quartz crystal thickness monitor. The porosity was very sensitive to the substrate temperature and decreased as the substrate temperature increased. Consistent behavior was observed among all of the materials in this study.
Posterminaries: Full Circle, Alexander H. King
Posterminaries: Full Circle, Alexander H. King
Alexander H. King
A few years ago, I was walking near the old Union Station in Pittsburgh with a colleague only slightly younger than myself, when we happened upon some large-scale relics of the steel industry displayed for public viewing. “You don’t see too many of those in public parking lots,” I offered. “Um… what is it?” was the response. I suppose I was just a little surprised that a prominent materials scientist did not recognize a Bessemer converter—arguably the principal source of wealth during the U.S. industrial revolution—but this conversation took place back when steel was in decline, and many university Materials …
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Song Zhang
This paper describes a novel phase error compensation method for reducing the measurement error caused by nonsinusoidal waveforms in phase-shifting methods. For 3-D shape measurement systems using commercial video projectors, the nonsinusoidal waveform of the projected fringe patterns as a result of the nonlinear gamma of projectors causes significant phase measurement error and therefore shape measurement error. The proposed phase error compensation method is based on our finding that the phase error due to the nonsinusoidal waveform depends only on the nonlinearity of the projector’s gamma. Therefore, if the projector’s gamma is calibrated and the phase error due to the …
Density Functional Study Of Structural Trends For Late-Transition-Metal 13-Atom Clusters, Lin-Lin Wang, Duane D. Johnson
Density Functional Study Of Structural Trends For Late-Transition-Metal 13-Atom Clusters, Lin-Lin Wang, Duane D. Johnson
Duane D. Johnson
Because reactivity increases as particle size decreases and competition between numerous structures are possible, which affects catalytic and magnetic properties, we study the structural trends of late-transition-metal 13-atom clusters using density functional theory within the generalized gradient approximation to exchange-correlation functional. We consider open structural motifs, such as bilayer and cubic (recently found to have lower energy), and find new bilayer candidates that are even lower in energy. To study the influence of d-orbital filling on structural trends, we focus on Pt, Pd, and Rh clusters and find several new, low-energy structures for Pt13 and Pd13 from searches using a …
Quantifying Total And Sustainable Agricultural Biomass Resources In South Dakota, Kurt A. Rosentrater, Russell Persyn, Dennis Todey
Quantifying Total And Sustainable Agricultural Biomass Resources In South Dakota, Kurt A. Rosentrater, Russell Persyn, Dennis Todey
Kurt A. Rosentrater
Conversion of biomass is considered the next major advance in biorenewable fuels, energy, and products. Wholesale conversion to biomass utilization could result in removal of current crop residues from agricultural fields or even implementation of different crops and cropping strategies (i.e., switchgrass). To date, the driver for biomass processing has been economics and limitations on the conversion of the lignocellulose. Over the last forty years significant investments and resultant changes in management practices in the agricultural sector have focused on soil and water conservation. One of the major efforts has focused on conservation-till or no-till, with the goal of retaining …
Organosilicas With Chiral Bridges And Self-Generating Mesoporosity, Andreas Ide, Rebecca Voss, Gudrun Scholz, Geoffrey A. Ozin, Markus Antonietti, Arne Thomas
Organosilicas With Chiral Bridges And Self-Generating Mesoporosity, Andreas Ide, Rebecca Voss, Gudrun Scholz, Geoffrey A. Ozin, Markus Antonietti, Arne Thomas
Rebecca Cademartiri
Amine-functionalized, chiral mesoporous organosilicas were prepared from a rationally designed precursor, which combines the functions of a network builder, a chiral latent functional group, and a porogen in one molecule. The precursors are formed by a convenient enantioselective hydroboration using (S)-monoisopinocampheylborane on an ethylene-bridged silica precursor. These precursors do self-organize when hydrolysis of their inorganic moiety takes place via an aggregation of their organic moiety into hydrophobic domains. After a condensation−ammonolysis sequence mesoporous organosilicas functionalized with chiral amine groups are obtained, with the complete chiral functionalities located at the pore wall surface and therefore accessible to chemical processes. The pore …
A Sum Frequency Generation Vibrational Spectroscopic Study Of The Adsorption And Reactions Of C6 Hydrocarbons At High Pressures On Pt(100), Kaitlin M. Bratlie, Gabor A. Somorjai
A Sum Frequency Generation Vibrational Spectroscopic Study Of The Adsorption And Reactions Of C6 Hydrocarbons At High Pressures On Pt(100), Kaitlin M. Bratlie, Gabor A. Somorjai
Kaitlin M. Bratlie
Sum frequency generation (SFG) vibrational spectroscopy was used to investigate the adsorption geometries and surface reactions of various C6 hydrocarbons (n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene) on Pt(100). At 300 K and in the presence of excess hydrogen, n-hexane, 3-methylpentane, and 2-methylpentane adsorb molecularly on Pt(100) mostly in “flat-lying” conformations. Upon heating the metal surface to 450 K, the molecules underwent dehydrogenation to form new surface species in “standing-up” conformations, such as hexylidyne and metallacyclic species.
Interface Reorientation During Coherent Phase Transformations, Valery I. Levitas, I. B. Ozsoy, D. L. Preston
Interface Reorientation During Coherent Phase Transformations, Valery I. Levitas, I. B. Ozsoy, D. L. Preston
Valery I. Levitas
The universal thermodynamic driving force for coherent plane interface reorientation (IR) during first-order phase transformations (PT) in solids is derived. The relation between the rates of IR and interface propagation (IP) and the corresponding driving forces are derived for combined athermal and drag interface friction. The coupled evolution of IR and IP during cubic-tetragonal and tetragonal-orthorhombic PTs under three-dimensional loading is studied. An instability in the interface orientation is shown to have the features of a first-order PT.
Compression Molding Of Phenolic Resin And Corn-Based Ddgs Blends, Kurt A. Rosentrater, R. A. Tatara, S. Suraparaju
Compression Molding Of Phenolic Resin And Corn-Based Ddgs Blends, Kurt A. Rosentrater, R. A. Tatara, S. Suraparaju
Kurt A. Rosentrater
With the rapid growth in the ethanol fuel industry in recent years, considerable research is being devoted to optimizing the use of processing coproducts, such as distillers dried grains with solubles (DDGS), in livestock diets. Because these residues contain high fiber levels, they may be amendable to incorporation into bio-based composites. Thus, the goal of this study was to demonstrate the viability of using corn-based DDGS as a biofiller with phenolic resin, in order to produce a novel biomaterial. DDGS was blended with phenolic resin at 0, 10, 25, 50, 75, and 90%, by weight, and then compression molded at …
First-Principles Prediction Of Phase-Segregating Alloy Phase Diagrams And A Rapid Design Estimate Of Their Transition Temperatures, Nikolai A. Zarkevich, Teck L. Tan, Duane D. Johnson
First-Principles Prediction Of Phase-Segregating Alloy Phase Diagrams And A Rapid Design Estimate Of Their Transition Temperatures, Nikolai A. Zarkevich, Teck L. Tan, Duane D. Johnson
Nikolai A. Zarkevich
We calculate the transition temperature versus concentration (Tc vs c) phase diagrams of several phase-segregating alloys [fcc Ca-Sr, Au-Pt, and Rh-(Pd,Cu,Ag,Au)] using a multiscale method combining first-principles calculations and Monte Carlo via the cluster expansion (CE). We study Pd-Rh, with its well-known high-T miscibility gap, to verify the method’s reliability. We predict that Ca-Sr segregates at low temperatures. We then show that a rapid estimate of Tc is obtained from enthalpies analytically derived from a CE, and, using thermodynamic integration, we determine under what circumstances this mean-field estimate is accurate compared to Monte Carlo results. Also, we discuss how an …
Generic Nonsinusoidal Phase Error Correction For Three-Dimensional Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Generic Nonsinusoidal Phase Error Correction For Three-Dimensional Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Song Zhang
A structured light system using a digital video projector is widely used for 3D shape measurement. However, the nonlinear γ of the projector causes the projected fringe patterns to be nonsinusoidal, which results in phase error and therefore measurement error. It has been shown that, by using a small look-up table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. We prove that this algorithm is generic for any phase-shifting algorithm. Moreover, we propose a new LUT generation method by analyzing the captured fringe image of a flat board directly. Experiments show that this …
A Fully Lagrangian Numerical Method For Calculating The Dynamics Of Oscillating Micro And Nanoscale Objects Immersed In Fluid, Nicole N. Hashemi, Mark Paul, Javier Alcazar, Raul Radovitzky
A Fully Lagrangian Numerical Method For Calculating The Dynamics Of Oscillating Micro And Nanoscale Objects Immersed In Fluid, Nicole N. Hashemi, Mark Paul, Javier Alcazar, Raul Radovitzky
Nastaran Hashemi
Many micro and nano-technologies rely upon the complicated motion of objects immersed in a viscous fluid. It is often the case that for such problems analytical theory is not available to quantitatively describe and predict the device dynamics. In addition, the numerical simulation of such devices involves moving boundaries and use of the standard Eulerian computational approaches are often difficult to implement. In order to address this problem we use and validate a fully Lagrangian finite element approach that treats the moving boundaries in a natural manner. We validate the method for use in calculating the dynamics of oscillating objects …
Thermal Effects On Mechanical Grinding-Induced Surface Texture In Tetragonal Piezoelectrics, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Thermal Effects On Mechanical Grinding-Induced Surface Texture In Tetragonal Piezoelectrics, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Alexander H. King
The effect of temperature on grinding-induced texture in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) has been investigated using in situ x-ray diffraction (XRD) with an area detector. In contrast with previous results on electrical poling, mechanically-ground PT and soft PZT materials retain strong ferroelastic textures during thermal cycling, even after excursions to temperatures slightly above the Curie temperature. The relationship between the residual stresses in the surface region, caused by grinding, and those resulting from domain wall motion is elucidated by in situ texture measurements obtained during thermal cycling.
How Surface Stresses Lead To Size-Dependent Mechanics Of Tensile Deformation In Nanowires, M. Ravi Shankar, Alexander H. King
How Surface Stresses Lead To Size-Dependent Mechanics Of Tensile Deformation In Nanowires, M. Ravi Shankar, Alexander H. King
Alexander H. King
It has been proposed that surface and interface stresses can modify the elastic behavior in nanomaterials such as nanowires. The authors show that surface stresses modify the tensile response of nanowires only when nonlinear elastic effects become important leading to cross terms between the applied stress and the surface stress. These effects are only significant when the radius of the nanowire is of the order of a few nanometers. The resulting alteration of tensile stiffness, though effected in part by the nonlinear elastic modulus, is particularly wrought by a modification of the stress state in the deformed nanowire.
Effect Of The Lattice Crystallinity On The Electron−Phonon Relaxation Rates In Gold Nanoparticles, Wenyu Huang, Wei Qian, Mostafa El-Sayed
Effect Of The Lattice Crystallinity On The Electron−Phonon Relaxation Rates In Gold Nanoparticles, Wenyu Huang, Wei Qian, Mostafa El-Sayed
Wenyu Huang
In order to study the importance of surface phonons on the electron−phonon relaxation in plasmonic nanoparticles, the effect of size, shape, and materials have recently been studied. Gold and silver nanoparticles have shown no dependence on size and shape while copper nanoparticles have shown some size dependence. This suggests that the bulk phonons, which are sensitive to the bulk-phase structure, are solely responsible for the relaxation of the hot electron in gold and silver plasmonic nanoparticles. The importance of bulk phonons should depend on the degree of crystallinity. In the present study, we have found that the electron−phonon relaxation rate …
On The Universal Scaling Behavior Of The Distance Decay Of Plasmon Coupling In Metal Nanoparticle Pairs: A Plasmon Ruler Equation, Prashant K. Jain, Wenyu Huang, Mostafa A. El-Sayed
On The Universal Scaling Behavior Of The Distance Decay Of Plasmon Coupling In Metal Nanoparticle Pairs: A Plasmon Ruler Equation, Prashant K. Jain, Wenyu Huang, Mostafa A. El-Sayed
Wenyu Huang
Localized surface plasmon resonances (LSPR) in lithographically fabricated gold (Au) nanodisc pairs are investigated using microabsorption spectroscopy and electrodynamic simulations. In agreement with previous work, we find that the fractional plasmon wavelength shift for polarization along the interparticle axis decays nearly exponentially with the interparticle gap. In addition, we find that the decay length is roughly about 0.2 in units of the particle size for different nanoparticle size, shape, metal type, or medium dielectric constant. The near-exponential distance decay and the interesting “universal” scaling behavior of interparticle plasmon coupling can be qualitatively explained on the basis of a dipolar-coupling model …
The Effect Of Plasmon Field On The Coherent Lattice Phonon Oscillation In Electron-Beam Fabricated Gold Nanoparticle Pairs, Wenyu Huang, Wei Qian, Prashant K. Jain, Mostafa El-Sayed
The Effect Of Plasmon Field On The Coherent Lattice Phonon Oscillation In Electron-Beam Fabricated Gold Nanoparticle Pairs, Wenyu Huang, Wei Qian, Prashant K. Jain, Mostafa El-Sayed
Wenyu Huang
By using electron beam lithography, we fabricated pairs of gold nanoparticles with varying interparticle separation. Double-beam femtosecond transient absorption spectroscopy was used to determine the coherent lattice oscillation frequency as a function of the interparticle separation in the presence of the plasmon field excited by the monitoring probe light. We found that the fractional shift in the coherent lattice phonon oscillation frequency follows an exponential decay with respect to the interparticle gap scaled by the disc diameter with the same decay constant as that previously observed for the fractional shift in the surface plasmon electronic oscillation resonance frequency. This strongly …
Multilevel Quality-Guided Phase Unwrapping Algorithm For Real-Time Three-Dimensional Shape Reconstruction, Song Zhang, Xiaolin Li, Shing-Tung Yau
Multilevel Quality-Guided Phase Unwrapping Algorithm For Real-Time Three-Dimensional Shape Reconstruction, Song Zhang, Xiaolin Li, Shing-Tung Yau
Song Zhang
A multilevel quality-guided phase unwrapping algorithm for real-time 3D shape measurement is presented. The quality map is generated from the gradient of the phase map. Multilevel thresholds are used to unwrap the phase level by level. Within the data points in each level, a fast scan-line algorithm is employed. The processing time of this algorithm is approximately 18.3 ms for an image size of 640×480 pixels in an ordinary computer. We demonstrate that this algorithm can be implemented into our real-time 3D shape measurement system for real-time 3D reconstruction. Experiments show that this algorithm improves the previous scan-line phase unwrapping …
Energy Pathways And Directionality In Deformation Twinning, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Energy Pathways And Directionality In Deformation Twinning, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Duane D. Johnson
We present ab initiodensity functional theory calculations of twinning energy pathways for two opposite twinning modes, (111)[112¯] and (111)[1¯1¯2], in fcc materials to examine the directional nature of twinning which cannot be explained by classical twin nucleationmodels or the “twinnability” criterion. By accounting for these energy pathways in a multiscale model, we quantitatively predict the critical twinning stress for the (111)[1¯1¯2] mode to be substantially higher compared to the favorable (111)[112¯] mode (whose predicted stresses are in agreement with experiment), thus, ruling out twinning in the (111)[1¯1¯2] mode.
Markov Chain Monte Carlo Defect Identification In Nde Images, Aleksandar Dogandžić, Benhong Zhang
Markov Chain Monte Carlo Defect Identification In Nde Images, Aleksandar Dogandžić, Benhong Zhang
Aleksandar Dogandžić
We derive a hierarchical Bayesian method for identifying elliptically‐shaped regions with elevated signal levels in NDE images. We adopt a simple elliptical parametric model for the shape of the defect region and assume that the defect signals within this region are random following a truncated Gaussian distribution. Our truncated‐Gaussian model ensures that the signals within the defect region are higher than the baseline level corresponding to the noise‐only case. We derive a closed‐form expression for the kernel of the posterior probability distribution of the location, shape, and defect‐signal distribution parameters (model parameters). This result is then used to develop Markov …
Microbial Development In Distillers Wet Grains Produced During Fuel Ethanol Production From Corn (Zea Mays), R. Michael Lehman, Kurt A. Rosentrater
Microbial Development In Distillers Wet Grains Produced During Fuel Ethanol Production From Corn (Zea Mays), R. Michael Lehman, Kurt A. Rosentrater
Kurt A. Rosentrater
Distillers grains are coproduced with ethanol and carbon dioxide during the production of fuel ethanol from the dry milling and fermentation of corn grain, yet there is little basic microbiological information on these materials. We undertook a replicated field study of the microbiology of distillers wet grains (DWG) over a 9 day period following their production at an industrial fuel ethanol plant. Freshly produced DWG had a pH of about 4.4, a moisture content of about 53.5% (wet mass basis), and 4 x 10(5) total yeast cells/g dry mass, of which about 0.1% were viable. Total bacterial cells were initially …