Browsing by Author "Schulz, JC"
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- ItemThe application of neutron reflectometry and atomic force microscopy in the study of corrosion inhibitor films(Elsevier B. V., 2006-11-15) John, D; Blom, ACM; Bailey, S; Nelson, A; Schulz, JC; De Marco, R; Kinsella, BCorrosion inhibitor molecules function by adsorbing to a steel surface and thus prevent oxidation of the metal. The interfacial structures formed by a range of corrosion inhibitor molecules have been investigated by in situ measurements based on atomic force microscopy and neutron reflectometry. Inhibitors investigated include molecules cetyl pyridinium chloride (CPC), dodecyl pyridinium chloride (DPC), 1-hydroxyethyl-2-oleic imidazoline (OHEI) and cetyl dimethyl benzyl ammonium chloride (CDMBAC). This has shown that the inhibitor molecules adsorb onto a surface in micellar structures. Corrosion measurements confirmed that maximum inhibition efficiency coincides with the solution critical micelle concentration. Copyright © 2006 Elsevier B.V.
- ItemThe application of neutron reflectometry and atomic force microscopy in the study of corrosion inhibitor films(The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) John, D; Blom, ACM; Bailey, S; Nelson, A; Schulz, JC; De Marco, R; Kinsella, BIn the search for new, superior and environmentally friendly corrosion inhibitor molecules, it is important to understand their mechanism of inhibition. Characterising the chemical and physical nature of the adsorbed inhibitor layer is a major part of understanding this mechanism. An accurate account of this character necessitates the use of surface analysis techniques that are capable of in-situ measurements. Ex-situ techniques are likely to cause changes either by oxidation of the metal and corrosion product film or rearrangement and loss of the inhibitor film during exposure to air and during the drying and analysis under vacuum. Neutron reflectometry in combination with atomic force microscopy provides the capability of in-situ surface analysis of thin interfacial layers. These complementary techniques make it possible to investigate the structure and orientation of molecules on a surface. which can ultimately assist in gaining an insight into the inhibitor mechanism. This paper will explore how these techniques can be used to determine the mechanism of corrosion inhibitors, with particular emphasis on surfactant molecules used to prevent carbon dioxide corrosion of steel during petroleum production. Results will be presented from experiments using the aforementioned in-situ surface analysis with generic corrosion inhibitor molecules cetyl pyridinium chloride (CPC), dodecyl pyridinium chloride (DPC), 1-hydroxyethyl-2-oleic imidazoline (OHEI) and cetyl dimethyl benzyl ammonium chloride (CDMBAC). These results will be further discussed with respect to the observed inhibition of carbon dioxide corrosion of carbon steel electrodes. © The Authors
- ItemAustralian Centre for Neutron Scattering update(Australian Nuclear Science and Technology Organisation, 2021-11-24) Schulz, JCThe Australian Centre for Neutron Scattering (ACNS) utilises neutrons from Australia's multi-purpose research reactor, OPAL, to solve complex research and industrial problems for Australian and international users via merit-based access and user-pays programs. Neutron scattering techniques provide the research community and industry with unique tools to study the structure, dynamics and properties of a range of materials, helping scientists understand why materials have the properties they do, and helping tailor new materials. An update will be given on the OPAL reactor and its neutron beam facilities, the status of the neutron beam instruments and supporting. © 2021 The Author
- ItemEvolution of the neutron-scattering capability on the OPAL reactor at ANSTO(Taylor & Francis Online, 2016-04-29) Klose, F; Constantine, P; Kennedy, SJ; Schulz, JC; Robinson, RA; Holden, PJ; McIntyre, GJAustralia is currently in the very privileged position of having the world's newest, fully operating research reactor, OPAL. As a consequence, the suite of neutron-beam instruments is also amongst the youngest and most advanced in the world, with full advantage taken in their construction of lessons learned at reactors elsewhere to develop state-of-the-art instruments that are best suited to the local and regional user communities. There are two thermal-neutron beam ports, two cold-neutron beam ports, and two (future) hot-neutron beam ports around the OPAL reactor core (see Fig. 3 in [1] and [2]). One each of the thermal-neutron and cold-neutron ports feed into a set of three guide bundles that serve the present (first) guide hall. In the initial construction phase, completed in 2007, only the outer two (TG1 and TG3) of the thermal guides, and the outer two (CG1 and CG3) of the cold guides were installed. The other thermal-neutron (TG4) and cold-neutron (CG4) guides are relatively short, to serve single instruments within the reactor beam hall with the highest flux but without eliminating line-of-sight [2]. Table 1 lists the current suite of instruments at the OPAL reactor, with brief technical details and the principal features. Figure 1 shows the layout of the current suite, with the anticipated location of the next instrument, BioRef (vide infra), indicated. We now briefly outline the evolution of the suite. © 2021 Informa UK Limited
- ItemNeutron reflectivity and atomic force microscopy studies on the effect of pH and solubilizate upon the structure of adsorbed cationic surfactant films on quartz(The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Schulz, JC; Nelson, A; Blom, ACM; War, GGWe have examined the adsorbed layer morphology of cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), on the hydrophilic quartz surface using atomic force microscopy (AFM) and neutron reflectometry (NR). We report on the effect of varying the surface charge of quartz by adjusting the bulk solution pH upon the adsorbed surfactant film structure. AFM results show that number density of globular (or spherical) TTAB aggregates on quartz increases, as the pH of the bulk solution is increased, reflecting the increase in surface charge of quartz. NR results also verify the AFM observations. We also report on the effect of the incorporation of a non-adsorbing solubilisate, naphthol, into the adsorbed surfactant film. In the bulk solution the incorporation of naphthol molecules into surfactant micelles promotes in micellar growth. Similarly, in the adsorbed surfactant film a transition to from globular to cylindrical surfactant aggregates was also observed. © 2005 The Authors
- ItemNovel cryogenic engineering solutions for the new Australian Research Reactor OPAL(American Institute of Physics, 2008-03-16) Olsen, SR; Kennedy, SJ; Kim, S; Schulz, JC; Thiering, R; Gilbert, EP; Lu, W; James, M; Robinson, RAIn August 2006 the new 20MW low enriched uranium research reactor OPAL went critical. The reactor has 3 main functions, radio pharmaceutical production, silicon irradiation and as a neutron source. Commissioning on 7 neutron scattering instruments began in December 2006. Three of these instruments (Small Angle Neutron Scattering, Reflectometer and Time-of-flight Spectrometer) utilize cold neutrons. The OPAL Cold Neutron Source, located inside the reactor, is a 20L liquid deuterium moderated source operating at 20K, 330kPa with a nominal refrigeration capacity of 5 kW and a peak flux at 4.2meV (equivalent to a wavelength of 0.4nm). The Thermosiphon and Moderator Chamber are cooled by helium gas delivered at 19.8K using the Brayton cycle. The helium is compressed by two 250kW compressors (one with a variable frequency drive to lower power consumption). A 5 Tesla BSCCO (2223) horizontal field HTS magnet will be delivered in the 2nd half of 2007 for use on all the cold neutron instruments. The magnet is cooled by a pulse tube cryocooler operating at 20K. The magnet design allows for the neutron beam to pass both axially and transverse to the field. Samples will be mounted in a 4K to 800K Gifford-McMahon (GM) cryofurnace, with the ability to apply a variable electric field in-situ. The magnet is mounted onto a tilt stage. The sample can thus be studied under a wide variety of conditions. A cryogen free 7.4 Tesla Nb-Ti vertical field LTS magnet, commissioned in 2005 will be used on neutron diffraction experiments. It is cooled by a standard GM cryocooler operating at 4.2K. The sample is mounted in a 2nd GM cryocooler (4K–300K) and a variable electric field can be applied. © 2008, American Institute of Physics
- ItemOverview of the OPAL Neutron Beam Facility(Australiasian Radiation Protection Society, 2012-10-16) Schulz, JCThe OPAL nuclear reactor, at Lucas Heights, is a 20 MW pool-type research reactor, using low enriched uranium. OPAL is a multi-purpose reactor utilised for scientific research using neutron beams, radioisotope production and silicon neutron transmutation doping. The OPAL reactor has been designed to provide high flux neutron beam facilities which supply neutrons to world class neutron beam instruments. There are presently seven neutron beam instruments which have been in operation since 2007 and another seven more under construction. An overview of the neutron beam facilities and instruments available at the OPAL reactor will be presented including the regulatory and radiation protection framework under which instruments are constructed, commissioned 8 operated and a summary of the radiation protection trends 8 issues encountered to date.
- ItemPlatypus: a time-of-flight neutron reflectometer at Australia's new research reactor(Taylor & Francis, 2007-01-31) James, M; Nelson, A; Brûlé, A; Schulz, JCA time-of-flight neutron reflectometer is to be built at the new 20 MW research reactor (OPAL) in Sydney. The instrument will be positioned at the end of a curved supermirror neutron guide that will provide optimal transmission of cold neutrons (2–20 Å) while removing fast neutrons and high-energy γ-rays. The reflectometer will utilise a white neutron beam that will be pulsed using a series of boron coated disc choppers. Typically three angle settings will be required to collect a complete reflectivity profile (from Q z = 0.005–0.5 Å− 1). The new instrument will operate with a vertical scattering plane, making it suitable for both solid and “free-liquid” surfaces. The instrument will also be capable of producing a spin-polarized neutron beam making provision for polarized neutron reflectometry studies. Detection of the reflected neutrons will take place using a 2-dimensional 3He delay-line detector with high-speed data acquisition electronics. © 2022 Informa UK Limited
- ItemQuokka: the small-angle neutron scattering instrument at OPAL(Australian Institute of Physics, 2006-12-05) Noakes, TJ; Christoforidis, J; Schulz, JC; Hamilton, WA; Gilbert, EPA small-angle neutron scattering (SANS) instrument[1] is being designed as part of the initial instrument suite for the new 20-MW Australian Reactor, OPAL. This instrument is designed to study structure on 1-100nm length scales on the wide variety of materials of scientific and technological importance for which neutron scattering has some considerable advantages over its x-ray counterpart, in particular (i) systems for which isotopic (H/D) contrast may be employed to highlight ordering, such as self-assembled polymer, surfactant and bio-molecule mesophases, and (ii) systems which scatter the neutron due to its magnetic moment, such as flux line penetration arrays in type II superconductors. The OPAL SANS instrument, receiving neutrons from a large liquid-D2 cold source, will be in the spirit of the world’s best facilities and will greatly build upon the Australian Nuclear Science and Technology Organisation’s existing expertise and facilities. Scheduled to begin operation in 2007, it will provide Australian and international researchers with opportunities to access state-of-the-art SANS instrumentation. [1] E.P. Gilbert, J.C. Schulz and Terry J. Noakes, Physica B, (2006) in press
- ItemQuokka: the small-angle neutron scattering instrument at OPAL(The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Gilbert, EP; Noakes, TJ; Schulz, JC; Baxter, P; Darmann, FA; Hauser, N; Abbeywick, P; Brûlé, A; Imamovic, E; Christoforidis, JA small-angle neutron scattering (SANS) instrument is being designed as part of the initial instrument suite for the 20-MW OPAL Reactor. The new instrument, receiving neutrons from a large liquid-D2 cold source, will be in the spirit of the worlds best facilities and will greatly build upon the Australian Nuclear Science and Technology Organisations existing expertise and facilities. Scheduled for completion in July 2006, it will provide Australian and international researchers with opportunities to access state-of-the-art SANS instrumentation. The details of the new SANS will be presented. © The Authors
- Item‘Quokka’—the small-angle neutron scattering instrument at OPAL(Elsevier B. V., 2006-11-15) Gilbert, EP; Schulz, JC; Noakes, TJA small-angle neutron scattering instrument (Quokka) is being built as part of the initial instrument suite for the 20 MW Australian Research Reactor, OPAL. The 40 m long instrument will be located at the end of a curved supermirror neutron guide and will receive neutrons from a large liquid-D2 cold source. The instrument will have incident beam polarisation and focusing optics using MgF2 lenses and gravity-correcting prisms in the collimation system. The secondary flight path includes a 1 m2 area detector with high-speed data acquisition electronics with provision for the inclusion of polarisation analysis at a later date. © 2006 Elsevier B.V.
- ItemThe structure of the di-block copolymer P2VP-PEO as a function of pH and temperature(The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Nelson, A; Gee, M; McLean, S; Schulz, JCPolymeric micelles are potential systems for controlled drug delivery. This is because poorly soluble drugs can be solubilised within the hydrophobicmicelle core, while the outer hydrophilic shell protects the drug recognition from the bodies clearance system. A potential polymer is poly(2vinlpyridine)-poly(ethylene oxide) (P2VP PEO). At low pH, this copolymer remains as unimers since the P2Vp and PEO blocks are hydrophilic. However at high pH the P2VP blocks de-pronate and become hydrophobic, only the PEO block is water soluble, resulting in micelle formation. In this situation the hydrophobic P2VP forms the micelle corea and the hydrophilic PEO a hydrated shell. It is envisaged that in drug delivery systems the polymeric micelle will adsorb to cell membranes in tumors. The pH sensitivity of these micelles would allow them to release their drug load close to the cell membrane, increasing its effectiveness . Through contract variation SANS experiments we have determined the internal structure of micelles (aspect ratio, size, core/shell hydration and aggregation number, etc) and their interactions with other micelles as temperature and Ph were varied. © The Authors
- ItemStudies of magnetic structure of La1-xSrxMnO3 colossal magnetoresistive perovskites(Australian Institute of Physics, 2004-02-04) Finlayson, TR; Wu, X; Ersez, T; Schulz, JCThis class of materials, based on the compound LaMnO3, continues to be the focus of attention because they exhibit colossal magnetoresistance (CMR) [1] which could lead to possible applications in magnetic recording and field sensors. In addition to the technological applications, the materials are important from a fundamental point of view due to the strong correlations between transport, structural and magnetic behaviour. The origin of the CMR effect has been attributed to the presence of magnetic polarons above the ferromagnetic ordering temperature, Tc. From recent research, using a combination of powder neutron diffraction, polarisation analysis and small-angle neutron scattering together with magnetic measurements, we present diffuse scattering, spin dynamics and lattice and magnetic correlations results for the La1-xSrxMnO3 (x=0.125 and 0.175) compounds. The diffuse scattering in the neutron diffraction patterns increases as the temperature approaches Tc from low temperature and continues to increase above Tc. The scattering peak in the forward direction above Tc (Tc