A5046149546- Nuclear Physics and Applications
- Microstructure and Mechanical Properties of Steels
- Welding Techniques and Residual Stresses
- Metallurgical Processes and Thermodynamics
- Microstructure and mechanical properties
- Advanced ceramic materials synthesis
- Nuclear Materials and Properties
- Solidification and crystal growth phenomena
- Aluminum Alloy Microstructure Properties
- High Temperature Alloys and Creep
- Non-Destructive Testing Techniques
- Hydrogen embrittlement and corrosion behaviors in metals
- Fusion materials and technologies
- X-ray Diffraction in Crystallography
- Metal and Thin Film Mechanics
- Iron and Steelmaking Processes
- Minerals Flotation and Separation Techniques
- Magnetic properties of thin films
- Ion-surface interactions and analysis
- Magnetic Properties and Applications
- nanoparticles nucleation surface interactions
- Aluminum Alloys Composites Properties
- Advanced Materials Characterization Techniques
- Nuclear reactor physics and engineering
- High-pressure geophysics and materials
Swansea University
2021-2022
University of Warwick
2014-2021
Carnegie Mellon University
2016
Laurentian University
2011
Oak Ridge National Laboratory
1995-2006
University of Missouri
1992-1999
Solid State Physics Laboratory
1999
University of Palermo
1989
University of Toyama
1986
Georgia Institute of Technology
1969-1981
Absolute calibration forms a valuable diagnostic tool in small-angle scattering experiments and allows the parameters of given model to be restricted set which reproduces observed intensity. General methods are available for absolute scaling X-ray (SAXS) data reviewed along with estimates degree internal consistency may achieved between various standards. In order minimize time devoted experimental program, emphasis is placed on developing precalibrated strongly standards SAXS facilities...
We have examined the kinetics of phase separation in ${\mathrm{Mn}}_{0.67}$${\mathrm{Cu}}_{0.33}$ using time-resolved neutron-scattering techniques. In an early-time regime, follows Cahn-Hilliard-Cook linear theory spinodal decomposition. There is intermediate stage. Then, at a late time, dynamic scaling obeyed. The time dependence wave vector maximum scattering intensity (which inversely proportional to average domain size) can be well described over entire late-time regime and much...
Room temperature 57Fe Mössbauer spectra were taken on atomically ordered and disordered iron-cobalt samples as a function of composition between 25 75 at.% cobalt. The degree long-range order was determined in selected using neutron diffraction. maximum values the effective field (He) isomer shift (I.S.) occur at cobalt where He=−365.5±0.5 kOe I.S. = +0.037±0.005 mm/sec (relative to pure iron). In range studied increasing number neighbors an iron atom either by ordering or concentration...
We performed inelastic neutron-scattering measurements on powdered ${\mathrm{Ni}}_{3}$Al. The alloy was prepared in two states of chemical order: (1) with equilibrium L${1}_{2}$ order, and (2) disorder (the material a fcc solid solution by high-energy ball milling). Procedures to convert the energy loss spectra into approximate phonon density (DOS) curves for ${\mathrm{Ni}}_{3}$Al order were guided Born--von K\'arm\'an analyses force constants obtained from previous single-crystal...
A series of experiments have been undertaken on the Oak Ridge National Laboratory (ORNL) 10 m small-angle X-ray scattering (SAXS) camera to provide quantitative data level background (parasitic) generated by different types bevelled collimating slits. The addition a third (guard) slit, positioned close sample, resulted in reduction over an order magnitude parasitic best two-slit combination This made it possible reduce size beamstop, permitting useful be collected down value vector Q =...
A precise study of fluxoid-line lattice (FLL) in the intermediate mixed state (IMS) a niobium-crystal sphere has been made with neutron-scattering technique. Accurate FLL unit-cell size determinations are facilitated by high angular resolution technique so that reversibility microscopic flux density applied-field history and near IMS can be demonstrated for first time. Structural changes associated hysteresis revealed through integrated intensities full widths at half-maxima rocking curves.
Children who are deaf or hard of hearing (D/HH) at high risk for permanent deficits in language acquisition and downstream effects such as poor academic performance, personal-social maladjustments, emotional difficulties. Identification children born D/HH through newborn screening subsequent timely early intervention can prevent reduce many these adverse consequences. Ongoing surveillance changes thresholds after infancy is also important should be accomplished by subjective assessment signs...
We performed inelastic neutron scattering measurements on nanophase Fe powders prepared by high-energy ball milling. Neutron energy loss spectra were measured for two states of the material: (1) as milled, when material had a characteristic nanocrystallite size 12 nm; and (2) annealed, crystallite 28 nm. The longitudinal peak in phonon density (DOS) was broadened, compared to that annealed material. attribute this broadening short lifetimes nanocrystals. also showed an enhanced at low...
Results from neutron inelastic-scattering experiments on Fe, Cr, and three bcc Fe-Cr alloys were analyzed with a Born--von K\'arm\'an model to obtain phonon density-of-states (DOS) curves. We compared the DOS of composite appropriate fractions pure metals Fe Cr. In high-temperature limit, we obtained vibrational entropy mixing Cr be 0.141, 0.201, 0.214 ${\mathit{k}}_{\mathit{B}}$/atom for ${\mathrm{Fe}}_{70}$${\mathrm{Cr}}_{30}$,${\mathrm{Fe}}_{53}$${\mathrm{Cr}}_{47}$,...
Samples of ${\mathrm{Ni}}_{3}$ V were prepared with two microstructures: (1) equilibrium ${\mathrm{D}0}_{22}$ order, and (2) partial disorder (having a large chemical order parameter, but without the tetragonality unit cell). For both materials, we measured difference in their heat capacities from 60 to 325 K, inelastic neutron-scattering spectra at four values Q 11 300 Young's moduli coefficients thermal expansion. The capacity low temperatures was consistent harmonic model using phonon...
Measurements of diffuse magnetic neutron scattering from an iron single crystal show that there is strong ferromagnetic short-range order above the Curie temperature. The associated small-angle spherically symmetric and decreases smoothly in reciprocal space, indicating no systematic orientation relationship between spin clusters. Correlation coefficients, defined as...
To move away from the 'take-make-dispose' economy there is a drive to reuse and recycle materials. For steel industry this means using more scrap. This has consequence on quality of produced due presence undesirable residuals In work, effect UK utilising national scrap stocks meet demand for explored through an iterative production model. Scrap qualities volumes were obtained compiled literature data generate reliable feed stock material. The considered in BF-BOF EAF routes model enrichment...
A theory is presented to describe the anomalous peak shift encountered in neutron diffraction residual stress measurements as specimen translated into and out of sampling volume, which defined by a pair masking slits inserted before after specimen. Analytical formulae for were obtained both position-sensitive-detector-based diffractometers conventional scanning diffractometers. The results indicate that observed complex function many variables, including in-pile collimation, slit widths,...
Aluminium foils (99.99% purity) and single crystals (99.999% were charged with hydrogen using a gas plasma method electrochemical methods, resulting in the introduction of large amount hydrogen. X-ray diffraction measurements indicated that within experimental error there was zero change lattice parameter after charging. This result is contradictory to almost all other face-centred cubic (f.c.c.) materials, which exhibit expansion when enters interstitially. It hypothesized does not enter as...
The structure of an alloy containing a high density precipitate particles is analyzed with the Percus-Yevick hard-sphere model to represent spatial arrangement precipitates. A commercial aluminum-lithium was heat treated produce nearly spherical precipitates having nominal composition ${\mathrm{Al}}_{3}$Li in matrix almost-pure aluminum. Small-angle x-ray scattering from foils by nonlinear fitting theoretical curve based on hard-sphere-liquid which satisfactorily represented particle size,...
Abstract Calcium treatment of aluminum killed steel was observed in situ using high-temperature confocal scanning laser microscope (HT-CSLM). This technique along with a novel experimental design enables continuous observation clustering behavior inclusions before and after the calcium treatment. Results show that increase average inclusion size non-calcium-treated condition much faster compared to calcium-treated condition. also magnitude attractive capillary force between particles...
Near-surface measurement of residual strain and stress with neutron scattering complements extends the surface measurements by X-ray diffraction. However, diffraction near surfaces are sensitive to volume alignment, beam wavelength spread collimation and, unless properly understood, can give large fictitious strains. An analytic calculation a numerical computation peak shifts due partial burial sampling have been made compared experimental measurement. Peak in strain-free nickel sample were...