Fresh water and acid sensitivity of authigenic clays in sandstone reservoirs

Authigenic illite-smectite and chlorite in reservoir sandstones from several Pacific rim sedimentary basins in Australia and New Zealand have been examined using an Electroscan Environmental Scanning Electron Microscope (ESEM) before, during, and after treatment with fresh water and HCl, respectively. These dynamic experiments are possible in the ESEM because, unlike conventional SEMs that require a high vacuum in the sample chamber (10-6 torr), the ESEM will operate at high pressures up to 20 torr. This means that materials and processes can be examined at high magnifications in their natural states, wet or dry, and over a range of temperatures (-20 to 1000 degrees C) and pressures. Sandstones containing the illite-smectite (60-70% illite interlayers) were flushed with fresh water for periods of up to 12 hours. Close examination of the same illite-smectite lines or filled pores, both before and after freshwater treatments, showed that the morphology of the illite-smectite was not changed by prolonged freshwater treatment. Chlorite-bearing sandstones (Fe-rich chlorite) were reacted with 1M to 10M HCl at temperatures of up to 80 degrees C and for periods of up to 48 hours. Before treatment the chlorites showed typically platy morphologies. After HCl treatment the chlorite grains were coated with an amorphous gel composed of Ca, Cl, and possibly amorphous Si, as determined by EDS analyses on the freshly treated rock surface. Brief washing in water removed this surface coating and revealed apparently unchanged chlorite showing no signs of dissolution or acid attack. However, although the chlorite showed no morphological changes, elemental analysis only detected silicon and oxygen.

Micrinite in Southern Hemisphere sub-bituminous and bituminous coals : redefined as fine grained kaolinite

A range of complementary analytical techniques including SEM/EDS, TEM/EDS and conventional optical microscopy has been rigorously applied to precisely defined areas of micrinite in polished coal samples from Australia and New Zealand. Elemental analyses of micrinite regions showed a high abundance of Al, Si and O and high resolution images of micrinite revealed a grain size < 1μm. Electron diffraction and elemental analyses from individual grains within the optically and electron-optically correlated micrinite regions are consistent with the occurence of fine-grained kaolinite. The optical properties of "dark clay" and "micrinite" (i.e. fine-grained kaolinite) can be understood in terms of the diffuse scattering of visible light from the surfaces of materials with different grain sizes in single-phase or multi-phase mixtures.

Postpartum diet quality in Australian women following a gestational diabetes pregnancy

BACKGROUND/OBJECTIVES: To describe the diet quality of a national sample of Australian women with a recent history of gestational diabetes mellitus (GDM) and determine factors associated with adherence to national dietary recommendations. SUBJECTS/METHODS: A postpartum lifestyle survey with 1499 Australian women diagnosed with GDM p3 years previously. Diet quality was measured using the Australian recommended food score (ARFS) and weighted by demographic and diabetes management characteristics. Multinominal logistic regression analysis was used to determine the association between diet quality and demographic characteristics, health seeking behaviours and diabetes-related risk factors. RESULTS: Mean (±s.d.) ARFS was 30.9±8.1 from a possible maximum score of 74. Subscale component scores demonstrated that the nuts/legumes, grains and fruits were the most poorly scored. Factors associated with being in the highest compared with the lowest ARFS quintile included age (odds ratio (OR) 5-year increase=1.40; 95% (confidence interval) CI:1.16–1.68), tertiary education (OR=2.19; 95% CI:1.52–3.17), speaking only English (OR=1.92; 95% CI:1.19–3.08), being sufficiently physically active (OR=2.11; 95% CI:1.46–3.05), returning for postpartum blood glucose testing (OR=1.75; 95% CI:1.23–2.50) and receiving riskreduction advice from a health professional (OR=1.80; 95% CI:1.24–2.60). CONCLUSIONS: Despite an increased risk of type 2 diabetes, women in this study had an overall poor diet quality as measured by the ARFS. Women with GDM should be targeted for interventions aimed at achieving a postpartum diet consistent with the guidelines for chronic disease prevention. Encouraging women to return for follow-up and providing risk reduction advice may be positive initial steps to improve diet quality, but additional strategies need to be identified.

Outcomes following inpatient rehabilitation : a seven year perspective

Introduction: Improving physical and cognitive functioning is a key objective of multi-disciplinary inpatient geriatric rehabilitation. Outcomes relevant to minimum functional ability required for older adults to successfully participate in the community have been reported. However, there has been little investigation reporting outcomes of older inpatients receiving multi-disciplinary rehabilitation being discharged home from geriatric rehabilitation units. This study aims to investigate characteristics and physical and cognitive outcomes of this cohort. Method: The Princess Alexandra Hospital Geriatric and Rehabilitation Unit is the largest rehabilitation unit in Queensland. Multidisciplinary health professionals enter admission and discharge functional and clinical outcomes along with demographic information into a purpose designed database for all patients. Data collected between 2005 and 2011 was analysed using descriptive statistics. Results: During the seven-year period, 4120 patients were admitted for rehabilitation; 2126 (52%) were female, mean age of 74 years (Standard Deviation 14). Primary reasons for admission were for reconditioning post medical illness or surgical admission (n = 1285, 31%), and 30% (n = 1233) admitted for orthopaedic reasons. Of these orthopaedic admissions, 6.6% (n = 82) were for elective surgery, and 46% (n = 565) were for fractured neck-of-femurs. 76% (n = 3130) of patients were discharged home, 13% (n = 552) to residential care facilities and 10% (n = 430) were discharged to an alternative hospital setting or passed away during their admission. Mean length of stay was 44 days (SD 39) Preliminary analysis of FIM outcomes shows a mean motor score of 53 (SD = 19) on admission which significantly improved to 71 (SD = 18) by discharge. There was no change on FIM cognitive score (28 (SD7) vs 29 (SD 6). Conclusion: Geriatric patients have significant functional limitations even on discharge from inpatient rehabilitation; though overall cognition is relatively intact. Orthopaedic conditions and general deconditioning from medical/surgical admissions are the main reasons for admission. The majority of people receiving rehabilitation are discharged home.

Melt textured Y123 bulk and thick film

YBa2Cu3O7-δ - 25mol%Y2BaCuO5 bars and thick films have been melt textured using a stationary furnace with a temperature gradient of 3 or 6°C/cm. Samples are heated above the peritectic reaction temperature and quenched to just above the solidification temperature and then slowly cooled below the solidification temperature. All bar shaped samples consist of 2-5 mm grains though the grain orientations strongly depend on the heat treatment conditions. The bar shows the maximum Jc of above 3,000 A/cm2, whereas the maximum Jc of 200 A/cm2 and Tczero of 88K are obtained for the thick film on (100) LaAlO3 single crystal.

Superconducting joints of Bi-2212/Ag tapes and laminates

Different types of HTS joints of Bi-2212/Ag tapes and laminates, which are fabricated by dip-coating and partial-melt processes, have been investigated. All joints are prepared using green single and laminated tapes and according to the scheme: coating-joining-processing. The heat treated tapes have critical current (Ic) between 7 and 27 A, depending on tape thickness and the number of Bi-2212 ceramic layers in laminated tapes. It is found that the current transport properties of joints depend on the type of laminate, joint configuration and joint treatment, Ic losses in joints of Bi-2212 tapes and laminates are attributed to defects in their structure, such as pores, secondary phases and misalignment of Bi-2212 grains near the Ag edges. By optimizing joint configuration, current transmission up to 100% is achieved for both single tapes and laminated tapes.

Binder effect on microstructure and properties of YBa2Cu3O7-x extruded wires

YBa2Cu3O7-x wires have been extruded with 2 and 5 wt.% of hydroxy propyl methylcellulose (HPMC) as binder. Both sets of wires sintered below 930°C have equiaxed grains while the wires sintered above this temperature have elongated grains. In the temperature range which gives equiaxed grains, the wires extruded with 5 wt.% HPMC have higher grain size and density. Cracks along the grain boundaries are often observed in the wires having elongated grains. Critical current density, Jc, increases initially, reaches a peak and then decreases with the sintering temperature. The sintering temperature giving a peak in Jc strongly depends on the heat treatment scheme for the wires extruded with 5 wt.% HPMC. TEM studies show that defective layers are formed along grain boundaries for the wires extruded with 5 wt.% HPMC after 5 h oxygenation. After 55 h oxygenation, the defective layers become more localised and grain boundaries adopt an overall cleaner appearance. Densification with equiaxed grains and clean grain boundaries produces the highest Jc's for polycrystalline YBa2Cu3O7 wires.

Bismuth oxide nanoparticles in the stratosphere

Platey grains of cubic Bi2O3, α-Bi2O3, and Bi2O2.75 nanograins were associated with chondritic porous interplanetary dust particles W7029C1, W7029E5, and 2011C2 that were collected in the stratosphere at 17-19 km altitude. Similar Bi oxide nanograins were present in the upper stratosphere during May 1985. These grains are linked to the plumes of several major volcanic eruptions during the early 1980s that injected material into the stratosphere. The mass of sulfur from these eruptions is a proxy for the mass of stratospheric Bi from which we derive the particle number densities (p m -3) for "average Bi2O3 nanograins" due to this volcanic activity and those necessary to contaminate the extraterrestrial chondritic porous interplanetary dust particles via collisional sticking. The match between both values supports the idea that Bi2O3 nanograins of volcanic origin could contaminate interplanetary dust particles in the Earth's stratosphere. Copyright 1997 by the American Geophysical Union.

The extrusion of continuous lengths of YBa2Cu3O7-x wire using hydroxypropyl methylcellulose

Wires of YBa2Cu3O7-x were fabricated by extrusion using a hydroxypropyl methylcellulose (HPMC) binder. As little as 2 wt.% binder was added to an oxide prepared by a novel co-precipitation process, to produce a plastic mass which readily gave continuous extrusion of long lengths of wire in a reproducible fashion. Critical temperatures of 92K were obtained for wires given optimum high-temperature heat treatments. Critical current densities greater than 1000 A cm-1 were measured at 77.3K using heat treatments at around 910°C for 10h. These transport critical current densities, measured on centimeter-long wires, were obtained with microstructures showing a relatively dense and uniform distribution of randomly oriented, small YBa2Cu3O7-x grains. © 1993.

Layer silicates in a chondritic porous interplanetary dust particle

Analytical electron microscopy on individual grains from a portion of a chondritic porous interplanetary dust particle (aggregate W7029C1 from the NASA Johnson Space Center Cosmic Dust Collection) shows that layer silicates compose 50 percent of the silicate fraction examined. These layer silicates can be classified into two distinct crystallochemical groups: (1) fine-grained, polycrystalline smectite minerals; and (2) well-ordered, single crystals of kaolinite and Mg-poor talc. The layer silicates in this portion of sample W7029(asterisk)A are dissimilar to those described in other chondritic porous aggregates. The predominant layer silicate assemblage in W7029(asterisk)A indicates that heating of the aggregate during atmospheric entry was brief and probably to a temperature less than 300C. Comparison with terrestrial phyllosilicate occurrences suggests that some layer silicates in aggregate W7029(asterisk)A may have been formed by alteratiton from preexisting silicate minerals at low temperatures (less than 25C) after aggregate formation.

Astrophysics and the solar nebula

The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) nucleation of refractory vapors at low pressure/high temperature; (2) coagulation of refractory grains; (3) optical properties of refractory grains; (4) mantle growth on refractory cores; (5) coagulation of core-mantle grains; (6) optical properties of core-mantle grains; (7) lightning strokes in the primitive solar nebula; and (8) separation of dust from a grain/gas mixture that interacts with a meter-sized planetesimal to determine if accretion occurs. The required capabilities and desired hardware for the facility are detailed.

Low temperature response of nanostructured tungsten oxide thin films toward hydrogen and ethanol

Semiconducting metal oxide based gas sensors usually operate in the temperature range 200–500 °C. In this paper, we present a new WO3 thin film based gas sensor for H2 and C2H5OH, operating at 150 °C. Nanostructured WO3 thin films were synthesized by thermal evaporation method. The properties of the as-deposited films were modified by annealing in air at 300 °C and 400 °C. Various analytical techniques such as AFM, TEM, XPS, XRD and Raman spectroscopy have been employed to characterize their properties. A clear indication from TEM and XRD analysis is that the as-deposited WO3 films are highly amorphous and no improvement is observed in the crystallinity of the films after annealing at 300 °C. Annealing at 400 °C significantly improved the crystalline properties of the films with the formation of about 5 nm grains. The films annealed at 300 °C show no response to C2H5OH (ethanol) and a little response to H2, with maximum response obtained at 280 °C. The films annealed at 400 °C show a very good response to H2 and a moderate response to C2H5OH (ethanol) at 150 °C. XPS analysis revealed that annealing of the WO3 thin films at 400 °C produces a significant change in stoichiometry, increasing the number of oxygen vacancies in the film, which is highly beneficial for gas sensing. Our results demonstrate that gas sensors with significant performance at low operating temperatures can be obtained by annealing the WO3 films at 400 °C and optimizing the crystallinity and nanostructure of the as-deposited films.

Metallic and Carbon Nanotube-Catalyzed Coupling of Hydrogenation in Magnesium

Synergistic effect of metallic couple and carbon nanotubes on Mg results in an ultrafast kinetics of hydrogenation that overcome a critical barrier of practical use of Mg as hydrogen storage materials. The ultrafast kinetics is attributed to the metal−H atomic interaction at the Mg surface and in the bulk (energy for bonding and releasing) and atomic hydrogen diffusion along the grain boundaries (aggregation of carbon nanotubes) and inside the grains. Hence, a hydrogenation mechanism is presented.

Electron microscopy of micron-sized lunar soil

We have performed electron-microscopic analysis on 0.5-1.0µm grains in order to study radiation damage by the solar-wind. We are reporting some interesting results we have found in monomineralic grains from core sample 15010,1130. This is a submature soil which has been studied for rare gas abundance and ferromagnetic resonance by (1) and modal petrology by (2).

Critical Literacy in the Early Years : Emergence and Sustenance in an Age of Accountability

The work of early childhood educators in facilitating young children’s literacy acquisition has never received more attention than in the new millennium. Media hype about literacy crises, falling standards, teacher quality and government promises of minimum standards for all children have simultaneously increased the ‘visibility’ of literacy and the stakes for school performance. Indeed the last two decades could be seen as an age of pronouncements with respect to literacy, with politicians internationally promising to cure supposed low literacy with standardized tests and mandated programmes. As the rhetoric around literacy intensifies many late-capitalist economies are experiencing shifts that have increased the gaps between rich and poor, changed the very nature of work, and fundamentally altered the cultural mix of their populations. More and more children attending schools where English is the language of instruction speak it as a second or third language. Many children have experienced the effects of war, terrorism, migration and poverty. Many live in fractured, fragmented and changing families. Teacher populations are changing too. In some places aging teacher workforces mean that there is already a shortage of qualified teachers. Literacy is also changing as the impact of digital technologies on global and local communication, economies and knowledges begins to bite in everyday and working lives. It is challenging to think about how spaces for the emergence and sustenance of critical literacy in early childhood education might be created.