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Articles 1 - 14 of 14
Full-Text Articles in Social and Behavioral Sciences
Metals Challenged By Neutron And Synchrotron Radiation, Klaus-Dieter Liss
Metals Challenged By Neutron And Synchrotron Radiation, Klaus-Dieter Liss
Faculty of Engineering and Information Sciences - Papers: Part B
In the past one and a half decades, neutron and synchrotron radiation techniques have come to the forefront as an excellent set of tools for the wider investigation of material structures and properties, becoming available to a large user community. This holds especially true for metals, which are a fascinating class of materials with both structural and functional applications. With respect to these application classes, metals are used to engineer bridges and automotive engines as well as to exploit magnetic and electric properties in computer storage, optics, and electronics. Both neutron sources and synchrotrons are large user facilities of quantum-beam …
Neutron Optics Upgrades To The Residual Stress Diffractometer, Kowari, Mark H. Reid, Scott Olsen, Vladimir Luzin, Mark New, Norman Booth, Douglas Clowes, Tai Nguyen, Ferdi Franceschini, Adrian Ogrin, Steven Pangalis, Ania Paradowska, Nathan P. Larkin, Zengxi Stephen Pan, Nicholas P. Hoye, Hiroshi Suzuki
Neutron Optics Upgrades To The Residual Stress Diffractometer, Kowari, Mark H. Reid, Scott Olsen, Vladimir Luzin, Mark New, Norman Booth, Douglas Clowes, Tai Nguyen, Ferdi Franceschini, Adrian Ogrin, Steven Pangalis, Ania Paradowska, Nathan P. Larkin, Zengxi Stephen Pan, Nicholas P. Hoye, Hiroshi Suzuki
Faculty of Engineering and Information Sciences - Papers: Part A
In the last 5 years a number of significant enhancements have been implemented on the neutron beam strain scanner Kowari at the OPAL reactor in Sydney Australia. These changes have resulted in reduced beam time losses when conducting experiments due to sample and stage alignment, and optics and sample changes. There have been 3 projects, starting in 2011 with a new manual slit system design and collision recovery system, in 2013 with a series of radial collimators and finally with the delivery of a 6 axis robot capable of texture measurements and of running up to 20 samples automatically.
Structural Evolution Of Electrodes In The Ncr And Cgr Cathode-Containing Commercial Lithium-Ion Batteries Cycled Between 3.0 And 4.5 V: An Operando Neutron Powder-Diffraction Study, Wei Kong Pang, Moshiul Alam, Vanessa K. Peterson, Neeraj Sharma
Structural Evolution Of Electrodes In The Ncr And Cgr Cathode-Containing Commercial Lithium-Ion Batteries Cycled Between 3.0 And 4.5 V: An Operando Neutron Powder-Diffraction Study, Wei Kong Pang, Moshiul Alam, Vanessa K. Peterson, Neeraj Sharma
Faculty of Engineering and Information Sciences - Papers: Part A
The dissimilar lattice-evolution of the isostructural layered Li(Ni,Co,Al)O2 (NCR) and Li(Ni,Co,Mn)O2 (CGR) cathodes in commercial lithium-ion batteries during overcharging/discharging was examined using operando neutron powder-diffraction. The stacking axis (c parameter) of both cathodes expands on initial lithiation and contracts on further lithiation. Although both the initial increase and later decrease are smaller for the CGR cathode, the overall change between battery charged and discharged states of the c parameter is larger for the CGR (1.29%) than for the NCR cathode (0.33%). We find these differences are correlated to the transition metal to oxygen bond (as measured through …
An In-Situ Neutron Diffraction Study Of A Multi-Phase Transformation And Twinning-Induced Plasticity Steel During Cyclic Loading, Ahmed A. Saleh, Donald W. Brown, Elena V. Pereloma, Bjorn Clausen, Christopher H. J Davies, Carlos N. Tome, Azdiar A. Gazder
An In-Situ Neutron Diffraction Study Of A Multi-Phase Transformation And Twinning-Induced Plasticity Steel During Cyclic Loading, Ahmed A. Saleh, Donald W. Brown, Elena V. Pereloma, Bjorn Clausen, Christopher H. J Davies, Carlos N. Tome, Azdiar A. Gazder
Faculty of Engineering and Information Sciences - Papers: Part A
In-situ neutron diffraction during cyclic tension-compression loading (þ3.5% to 2.8%) of a 17Mn-3Al-2Si-1Ni-0.06C steel that exhibits concurrent transformation and twinning -induced plasticity effects indicated a significant contribution of intragranular back stresses to the observed Bauschinger effect. Rietveld analysis revealed a higher rate of martensitic transformation during tension compared to compression. Throughout cycling, a0-martensite exhibited the highest phase strains such that it bears an increasing portion of the macroscopic load as its weight fraction evolves. On the other hand, the e-martensite strain remained compressive as it accommodated most of the internal strains caused by the shape misfit associated with the c!e …
Neutron-Gamma Pulse Shape Discrimination Using Organic Scintillators With Silicon Photomultiplier Readout, Rhys M. Preston, John Eberhardt, James Tickner
Neutron-Gamma Pulse Shape Discrimination Using Organic Scintillators With Silicon Photomultiplier Readout, Rhys M. Preston, John Eberhardt, James Tickner
Faculty of Engineering and Information Sciences - Papers: Part A
Neutron/Gamma pulse shape discrimination (PSD) was measured using stilbene and EJ-299-34 plastic scintillators with readout by silicon photomultipliers (SiPMs). The SiPM pulses were digitized and processed for energy and pulse shape information using a digital technique performing numerical weighted integrations on each pulse. A genetic algorithm (GA) was developed to optimize the weighting vectors used for the pulse shape discrimination. Efficient PSD was obtained down to an electron-equivalent energy of 127 keV with stilbene and 391 keV with the EJ-299-34 PSD plastic. Separation at lower energies was possible at reduced detection efficiency, down to 78 keV and 186 keV at …
Residual Stresses In Rail-Ends From The In-Service Insulated Rail Joints Using Neutron Diffraction, Vladimir Luzin, Chandrahas Rathod, David Wexler, Paul Boyd, Manicka Dhanasekar
Residual Stresses In Rail-Ends From The In-Service Insulated Rail Joints Using Neutron Diffraction, Vladimir Luzin, Chandrahas Rathod, David Wexler, Paul Boyd, Manicka Dhanasekar
Faculty of Engineering and Information Sciences - Papers: Part A
Insulated rail joints (IRJs) are an integral part of the rail track signaling system and pose significant maintenance and replacement costs due to their low and fluctuating service lives. Failure occurs mainly in rail head region, bolt-holes of fishplates and web-holes of the rails. Propagation of cracks is influenced by the evolution of internal residual stresses in rails during rail manufacturing (hot-rolling, roller-straightening, and head-hardening process), and during service, particularly in heavy rail haul freight systems where loads are high. In this investigation, rail head accumulated residual stresses were analysed using neutron diffraction at the Australian Nuclear Science and Technology …
Defect Dynamics In Polycrystalline Zirconium Alloy Probed In Situ By Primary Extinction Of Neutron Diffraction, Saurabh Kabra, Kun Yan, David G. Carr, Robert P. Harrison, Rian J. Dippenaar, Mark Reid, Klaus-Dieter Liss
Defect Dynamics In Polycrystalline Zirconium Alloy Probed In Situ By Primary Extinction Of Neutron Diffraction, Saurabh Kabra, Kun Yan, David G. Carr, Robert P. Harrison, Rian J. Dippenaar, Mark Reid, Klaus-Dieter Liss
Faculty of Engineering and Information Sciences - Papers: Part A
After α + β-zirconium has fully transformed into β-phase upon heating, the intensities of all β-Zr Bragg reflections decrease simultaneously as a function of time. It is shown that this effect represents a transition from the kinematic to the dynamic theory of diffraction due to the ever increasing crystal perfection driven by thermal recovery of the system. The best fitting coherent crystallite size of 30 μm and other microstructural features are verified by in situ laser scanning confocal microscopy. This effect of primary extinction in neutron diffraction has been employed to further investigate the crystal perfection kinetics. Upon further heating, …
Neutron Generator Burst Timing Measured Using A Pulse Shape Discrimination Plastic Scintillator With Silicon Photomultiplier Readout, R M. Preston, J Eberhardt, J R. Tickner
Neutron Generator Burst Timing Measured Using A Pulse Shape Discrimination Plastic Scintillator With Silicon Photomultiplier Readout, R M. Preston, J Eberhardt, J R. Tickner
Faculty of Engineering and Information Sciences - Papers: Part A
An EJ-299-34 plastic scintillator with silicon photomultiplier (SiPM) readout was used to measure the fast neutron output of a pulsed Thermo-Fisher A-325 Deuterium-Tritium sealed tube neutron generator (STNG). The SiPM signals were handled by a prototype digital pulse processing system, based on a free-running analogue to digital converter feeding a digital signal processor (DSP). Pulse shape discrimination was used to distinguish between detected fast-neutrons and gammas. Pulse detection, timing, energy and shape were all processed by the DSP in real-time.
Development Of Sipm-Based Scintillator Tile Detectors For A Multi-Layer Fast Neutron Tracker, R Preston, J Jakubek, D Prokopovich, J Uher
Development Of Sipm-Based Scintillator Tile Detectors For A Multi-Layer Fast Neutron Tracker, R Preston, J Jakubek, D Prokopovich, J Uher
Faculty of Engineering and Information Sciences - Papers: Part A
We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM) readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 x 15 x 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The …
Specific Cellular Water Dynamics Observed In Vivo By Neutron Scattering And Nmr., Moeava Tehei, Marion Jasnin, Andreas Stadler, Giuseppe Zaccai
Specific Cellular Water Dynamics Observed In Vivo By Neutron Scattering And Nmr., Moeava Tehei, Marion Jasnin, Andreas Stadler, Giuseppe Zaccai
Faculty of Science - Papers (Archive)
Neutron scattering, by using deuterium labelling, revealed how intracellular water dynamics, measured in vivo in E. coli, human red blood cells and the extreme halophile, Haloarcula marismortui, depends on the cell type and nature of the cytoplasm. The method uniquely permits the determination of motions on the molecular length (Ba˚ ngstrøm) and time (pico- to nanosecond) scales. In the bacterial and human cells, intracellular water beyond the hydration shells of cytoplasmic macromolecules and membrane faces flows as freely as liquid water. It is not ‘‘tamed’’ by confinement. In contrast, in the extreme halophile archaeon, in addition to free and hydration …
Hydration Dependent Studies Of Highly Aligned Multilayer Lipid Membranes By Neutron Scattering , Marcus Trapp, Thomas Gutberlet, Fanni Juranyi, T Unruh, Bruno Demé, Moeava Tehei, Judith Peters
Hydration Dependent Studies Of Highly Aligned Multilayer Lipid Membranes By Neutron Scattering , Marcus Trapp, Thomas Gutberlet, Fanni Juranyi, T Unruh, Bruno Demé, Moeava Tehei, Judith Peters
Faculty of Science - Papers (Archive)
We investigated molecular motions on a picoseconds timescale of 1,2-Dimyristoyl-sn- Glycero-3-Phosphocholine (DMPC) model membranes as a function of hydration by using elastic and quasielastic neutron scattering. Two different hydrations corresponding to approximately nine and twelve water molecules per lipid were studied, the latter being the fully hydrated state. In our study we focused on head group motions by using chain deuterated lipids. Information on in-plane and out-of-plane motions could be extracted by using solid supported DMPC multilayers. Our studies confirm and complete former investigations by K¨onig et al. and Rheinst¨adter et al. who describe the dynamics of lipidmembranes, but did …
Dynamics Of Apomyoglobin In The Α-To-Β Transition And Of Partially Unfolded Aggregated Protein, E. Fabiani, A. M. Stadler, D. Madern, M. M. Koza, M. Tehei, M. Hirai, G. Zaccai
Dynamics Of Apomyoglobin In The Α-To-Β Transition And Of Partially Unfolded Aggregated Protein, E. Fabiani, A. M. Stadler, D. Madern, M. M. Koza, M. Tehei, M. Hirai, G. Zaccai
Faculty of Science - Papers (Archive)
Changes of molecular dynamics in the α-to-β transition associated with amyloid fibril formation were explored on apo-myoglobin (ApoMb) as a model system. Circular dichroism, neutron and X-ray scattering experiments were performed as a function of temperature on the protein, at different solvent conditions. A significant change in molecular dynamics was observed at the α-to-β transition at about 55 ˚C, indicating a more resilient high temperature β structure phase. A similar effect at approximately the same temperature was observed in holo-myoglobin, associated with partial unfolding and protein aggregation. A study in a wide temperature range between 20 K and 360 K …
Protein Dynamics And Stability: The Distribution Of Atomic Fluctuations In Thermophilic And Mesophilic Dihydrofolate Reductase Derived Using Elastic Incoherent Neutron Scattering, Lars Meinhold, David Clement, Moeava Tehei, Roy Daniel, John L. Finney, Jeremy C. Smith
Protein Dynamics And Stability: The Distribution Of Atomic Fluctuations In Thermophilic And Mesophilic Dihydrofolate Reductase Derived Using Elastic Incoherent Neutron Scattering, Lars Meinhold, David Clement, Moeava Tehei, Roy Daniel, John L. Finney, Jeremy C. Smith
Faculty of Science, Medicine and Health - Papers: part A
The temperature dependence of the dynamics of mesophilic and thermophilic dihydrofolate reductase is examined using elastic incoherent neutron scattering. It is demonstrated that the distribution of atomic displacement amplitudes can be derived from the elastic scattering data by assuming a (Weibull) functional form that resembles distributions seen in molecular dynamics simulations. The thermophilic enzyme has a significantly broader distribution than its mesophilic counterpart. Furthermore, although the rate of increase with temperature of the atomic mean-square displacements extracted from the dynamic structure factor is found to be comparable for both enzymes, the amplitudes are found to be slightly larger for the …
Dynamics Of Immobilized And Native Escherichia Coli Dihydrofolate Reductase By Quasielastic Neutron Scattering, M. Tehei, J. Smith, C. Monk, J. Ollivier, M. Oettl, V. Kurkal, J. L. Finney, R. M. Daniel
Dynamics Of Immobilized And Native Escherichia Coli Dihydrofolate Reductase By Quasielastic Neutron Scattering, M. Tehei, J. Smith, C. Monk, J. Ollivier, M. Oettl, V. Kurkal, J. L. Finney, R. M. Daniel
Faculty of Science - Papers (Archive)
The internal dynamics of native and immobilized Escherichia coli dihydrofolate reductase (DHFR) have been examined using incoherent quasielastic neutron scattering. These results reveal no difference between the high frequency vibration mean-square displacement of the native and the immobilized E. coli DHFR. However, length-scale-dependent, picosecond dynamical changes are found. On longer length scales, the dynamics are comparable for both DHFR samples. On shorter length scales, the dynamics is dominated by local jump motions over potential barriers. The residence time for the protons to stay in a potential well is t=7.95 ps for the native DHFR and t=20.36 ps for the immobilized …