About
27
Publications
3,375
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
463
Citations
Introduction
Skills and Expertise
Current institution
Publications
Publications (27)
FeCrAl alloys are among the best and most mature accident tolerant fuel cladding candidates produced to date, due to their superior combination of mechanical properties and stability at elevated temperatures. For fuel cladding applications, these materials are drawn into tubes with plugs welded to the ends. The mechanical properties of such welds a...
Large strain machining (LSM), an attractive severe deformation technique due to its simplicity, has been previously used to produce a fine-grained structure in a variety of alloys. An equiatomic CrFeMnNi high entropy alloy was subject to various LSM conditions. The microstructure was observed to have ultra-fine grains in all conditions, with some m...
Focused ion beam machining revolutionized the way samples are studied in materials science. The introduction of this tool enabled researchers to break into new frontiers of research. While this method focused on the nanometer length scale, the mesoscale manufacturing of samples has not seen such advances. It remains a challenge to manufacture sampl...
Femtosecond laser cutting has been used to fabricate micro- and mesoscale specimens for mechanical testing, but the impact on mechanical properties has not been fully evaluated. Micropillars of various sizes were fabricated in a single crystal Cu specimen and Cu irradiated to 1.4 peak displacements per atom using a femtosecond laser cutting system...
Engineered tissue barrier models offer in vitro alternatives in toxicology and disease research. To mimic barrier-tissue microenvironment, a porous membrane that can approach the stiffness of physiological basement membranes is required. While several biocompatible membranes with micron range thickness (10 µm) and a stiffness less than polystyrene...
Ultra-thin and strong formvar-based membranes with controlled morphologies were developed via a simple synthesis technique. This thin hydrophilic and oleophilic polymer possesses very interesting morphological properties including being inert to most chemicals and resistant to radiation. Tunable porous membranes (porosity ranges from 20 to 60%) wer...
We present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness an...
Microfluidic investigations of flow and transport in porous and fractured media have the potential to play a significant role in the development of future subsurface energy resource technologies. However, the majority of experimental systems to date are limited in applicability due to operating conditions and/or the use of engineered material micro...
div class="title">Studying Shocked Material Dynamics with Ultrafast X-rays
- Volume 21 Issue S3 - R.L. Sandberg, C. Bolme, K. Ramos, Q. McCulloch, R. Martinez, V. Hamilton, T. Pierce, M. Greenfield, S. McGrane, J.L. Barber, B. Abbey, A. Schropp, F. Seiboth, P. Heiman, B. Nagler, E. Galtier, E. Granados
We present the first single-shot images of laser-driven shock waves interacting with micron-scale materials inhomogeneities taken with an X-ray free electron laser. Materials dynamics under high strain-rate loading is important to a range of problems.
Damage initiation and evolution, failure, and recollection processes under axisymmetric convergence were studied in the Russian-Damage experimental series, a joint effort between the Los Alamos National Laboratory and the All-Russian Institute of Experimental Physics. A helical explosive magnetic generator was used to drive a cylindrical liner shel...
An all optical-fiber-based approach to measuring high explosive detonation front position and velocity is described. By measuring total light return using an incoherent light source reflected from a fiber Bragg grating sensor in contact with the explosive, dynamic mapping of the detonation front position and velocity versus time is obtained. We dem...
An all optical-fiber-based approach to measuring high explosive detonation front position and velocity is described. By measuring total light return using an incoherent light source reflected from a linearly chirped fiber Bragg grating sensor in contact with the explosive, dynamic mapping of the detonation front position and velocity versus time is...
An ultrafast, fiber-based laser fabrication system has been developed. This system has been used for many applications including THz metamaterials, waveguides, microfluidic devices, and here we detail work on Chirped Fiber Bragg Grating Sensors.
We report a novel ultrafast optical system capable of directly pumping low energy excitations in complex materials and probing the photoinduced changes in their properties with terahertz pulses, benchmarked through mid-infrared-pump, THz-probe measurements on InSb.
We report a novel ultrafast optical system capable of directly pumping low energy excitations in complex materials and probing the photoinduced changes in their properties with terahertz pulses, benchmarked through mid-infrared-pump, THz-probe measurements on InSb.
We have studied the picosecond lattice dynamics of optically pumped hexagonal LuMnO3 by using ultrafast x-ray diffraction. The results show a shift and broadening of the diffraction curve due to the stimulated lattice expansion. To understand the transient response of the lattice, the measured time- and angle-resolved diffraction curves are compare...
In the three joint VNIIEF/LANL experiments RHSR-0,1,2 with a disk EMG and a three-layer liner system (Al-dielectric-Cu) a method of radial radiography was used to study growth of perturbations amplitude at the boundary between copper layer and polyethylene (in experiments RHSR-0,1) and water (in experiment RHSR-2); the growth occurs during the evol...
We have studied the picosecond-dynamics of optically pumped hexagonal LuMnO<sub>3</sub> using ultrafast X-ray diffraction. Experimental data are compared with a simulation based on dynamical diffraction theory modified to account for the hexagonal structure of LuMnO<sub>3</sub>.
Many pulsed-power facilities used for high energy density experiments require diagnostics that can measure the velocity histories of shocked materials. The Atlas pulsed-power z-pinch machine [1] (located at the Nevada Test Site) is a 23-megajoule capacitor bank capable of delivering 28 mega-amperes in an approximately 5 microsecond rise time pulse...
The use of X‐ray diffraction for the study of shock physics has been pursued for decades. Conceptually, changes in the diffraction line, including broadening and shifts, provide details about the nature of compression, plasticity, phase, and kinetics of the phase transition for the material being shock‐loaded. In practice, X‐ray source brightness,...
We present the results of terahertz spectroscopic studies on single crystals of the energetic material HMX at various temperatures and crystal orientations. Distinct intermolecular vibrational modes are observed in the range from 55-75 cm-1.
We present the results of terahertz spectroscopic studies on single crystals of the energetic material HMX at various temperatures and crystal orientations. Distinct intermolecular vibrational modes are observed in the range from 55 - 75 cm-1
Excitons and charged excitons (trions) are investigated in ZnSe-based quantum well structures with (Zn,Be,Mg)Se and (Zn,Mg)(S,Se)
barriers by means of magneto-optical spectroscopy. Binding energies of negatively (X−) and positively (X+) charged excitons are measured as functions of quantum well width, free carrier density and in external magnetic f...
Singlet and triplet states of negatively (X-) and positively (X+) charged excitons (trions) in ZnSe-based quantum wells have been studied by means of photoluminescence in pulsed magnetic fields to 50 Tesla. Singlet state binding energies of X- show a monotonic increase with growing magnetic fields with a tendency to saturation. Contrary to that a d...
Excitons and charged excitons (trions) are investigated in ZnSe-based quantum well structures with (Zn,Be,Mg)Se and (Zn,Mg)(S,Se) barriers by means of magneto-optical spectroscopy. Binding energies of negatively () and positively (X+) charged excitons are measured as functions of quantum well width, free carrier density and in external magnetic fie...
