Calcite precipitation induced by clay-bleach cation exchange in andesitic reservoir rocks

Experiments were carried out on the sodium hypochlorite bleach sensitivity of a deep subsurface andesitic reservoir in order to predict possible deleterious mineral transformations during a downhole clean-up job. Experiments involved examination of core samples from the reservoir using an Environmental Scanning Electron Microscope (ESEM) with an attached Energy Dispersive Spectrometer (EDS) before and after the samples were immersed in bleach. Bleach immersion of whole-rock samples resulted in rapid (less than 1 min) precipitation of abundant 3.0-10.0-μm-wide calcite rhombs within clay-associated micropores and on clay and feldspar grain surfaces. Abundant microporefilling calcite rhombs also formed in pure separates of constituent chlorite/corrensite, whereas no calcite formed in a pure separate of constituent zeolite. These experiments indicate that corrensite is the likely calcium source in this experimental fluid-rock system. Formation of calcite occurs via a cation exchange reaction in which calcium in the smectitic interlayers of corrensite exchanges for sodium in the bleach. Serious formation damage due to calcite precipitation would have occurred in the andesite reservoir had it been exposed to bleach. This finding gives credence to earlier suggestions that cation exchange reactions have the potential to cause calcite precipitation in some sandstone reservoirs when exposed to drilling, completion or stimulation fluids. © 1993.

Removal of epoxy-attached thin-sections from glass slides by plasma-etching

Thin-sectioned samples mounted on glass slides with common petrographic epoxies cannot be easily removed (for subsequent ion-milling) by standard methods such as heating or dissolution in solvents. A method for the removal of such samples using a radio frequency (RF) generated oxygen plasma has been investigated for a number of typical petrographic and ceramic thin sections. Sample integrity and thickness were critical factors that determined the etching rate of adhesive and the survivability of the sample. Several tests were performed on a variety of materials in order to estimate possible heating or oxidation damage from the plasma. Temperatures in the plasma chamber remained below 138°C and weight changes in mineral powders etched for 76 hr were less than ±4%. A crystal of optical grade calcite showed no apparent surface damage after 48 hr of etching. Any damage from the oxygen plasma is apparently confined to the surface of the sample, and is removed during the ion-milling stage of transmission electron microscopy (TEM) sample preparation.

Silver Gelatin Print: A group exhibition curated by Karen Milder that investigates and captures the traditional processes using photograms, liquid emulsion, toning, hand-colouring and film. Part of the Queensland Festival of Photography 4 (QFP4).

Pillar of salt: (3 hand-applied silver gelatin photographs) Statement: For women moving into new experiences and spaces, loss and hardship is often a price to be paid. These courageous women look back to things they have overcome in order to continue to grow.

Chemical vapor deposited boron carbide : growth by a vapor-liquid-solid process

Detailed analytical electron microscope (AEM) studies of yellow whiskers produced by chemical vapor deposition (CVD)1 show that two basic types of whiskers are produced at low temperatures (between 1200°C and 1400°C) and low boron to carbon gas ratios. Both whisker types show planar microstructures such as twin planes and stacking faults oriented parallel to, or at a rhombohedral angle to, the growth direction. For both whisker types, the presence of droplet-like terminations containing both Si and Ni indicate that the growth process during CVD is via a vapor-liquid-solid (VLS) mechanism.

Grey St. Xchange 2.0 by QUT

Partnerships between universities and public institutions such as this offer the beginning of a long term relationship to actively influence public policy, procedures and new ways to engage the many diverse communities to be integral in shaping the environments in which they live. It offers an opportunity to apply authentic positioning of research theories and build new methodologies for consulting, analysing and implementing innovation. SBC, as an established corporation offers a unique precinct to research and develop models with its different offers of tourism, leisure and neighbourhood. The Parklands and Little Stanley Street are well advanced in the goals however Grey Street, which connects the precinct to the greater surrounds, has been a complex issue that is now ready to be addressed. This project offers the ability to be of real worth at this critical time of development with the history of the past development combined with the desire for future visioning to be realised over the next 5 years. QUT has the unique opportunity to be part of this future.

Structure of the immature retroviral capsid at 8 Å resolution by cryo-electron microscopy

The assembly of retroviruses such as HIV-1 is driven by oligomerization of their major structural protein, Gag. Gag is a multidomain polyprotein including three conserved folded domains: MA (matrix), CA (capsid) and NC (nucleocapsid)(1). Assembly of an infectious virion proceeds in two stages(2). In the first stage, Gag oligomerization into a hexameric protein lattice leads to the formation of an incomplete, roughly spherical protein shell that buds through the plasma membrane of the infected cell to release an enveloped immature virus particle. In the second stage, cleavage of Gag by the viral protease leads to rearrangement of the particle interior, converting the non-infectious immature virus particle into a mature infectious virion. The immature Gag shell acts as the pivotal intermediate in assembly and is a potential target for anti-retroviral drugs both in inhibiting virus assembly and in disrupting virus maturation(3). However, detailed structural information on the immature Gag shell has not previously been available. For this reason it is unclear what protein conformations and interfaces mediate the interactions between domains and therefore the assembly of retrovirus particles, and what structural transitions are associated with retrovirus maturation. Here we solve the structure of the immature retroviral Gag shell from Mason-Pfizer monkey virus by combining cryo-electron microscopy and tomography. The 8-angstrom resolution structure permits the derivation of a pseudo-atomic model of CA in the immature retrovirus, which defines the protein interfaces mediating retrovirus assembly. We show that transition of an immature retrovirus into its mature infectious form involves marked rotations and translations of CA domains, that the roles of the amino-terminal and carboxy-terminal domains of CA in assembling the immature and mature hexameric lattices are exchanged, and that the CA interactions that stabilize the immature and mature viruses are almost completely distinct.

Intercalation of kaolins by alkaline earth metal salts

A suite of new materials, based on chemical modification of kaolins, has been successfully prepared via manipulation of the kaolin structure and subsequent intercalation by CaCl2 and MgCl2. A standard kaolinite(KGa-1)and a commercially available halloysite (New Zealand china clay) were used for this study. The kaolins are given several cycles of intercalation and deintercalation using a common intercalant such as potassium acetate. The number of cycles given depends on the type of kaolin. After this treatment, both kaolinite and halloysite hydrate show considerable broadening of the (00l) reflections which indicate extensive exfoliation of the layers. In the case of kaolinite, exfoliated layers roll to form tubes similar to proper halloysite. Kaolins modified by the above treatment readily intercalate MgCl2 and CaCl2 from saturated solutions of these salts. On intercalation with CaCl2 and MgCl2, kaolinite layers expand to 10A and 9.8A, and those of halloysite to 12.8A and 15.5A, respectively. To our knowledge, this is the first report of successful intercalation of alkaline-earth halides by kaolins.

Order conditions of stochastic Runge-Kutta methods by B-series

In this paper, general order conditions and a global convergence proof are given for stochastic Runge Kutta methods applied to stochastic ordinary differential equations ( SODEs) of Stratonovich type. This work generalizes the ideas of B-series as applied to deterministic ordinary differential equations (ODEs) to the stochastic case and allows a completely general formalism for constructing high order stochastic methods, either explicit or implicit. Some numerical results will be given to illustrate this theory.

STALKERBOT : learning to navigate dynamic human environments by following people

Service robots that operate in human environments will accomplish tasks most efficiently and least disruptively if they have the capability to mimic and understand the motion patterns of the people in their workspace. This work demonstrates how a robot can create a humancentric navigational map online, and that this map re ects changes in the environment that trigger altered motion patterns of people. An RGBD sensor mounted on the robot is used to detect and track people moving through the environment. The trajectories are clustered online and organised into a tree-like probabilistic data structure which can be used to detect anomalous trajectories. A costmap is reverse engineered from the clustered trajectories that can then inform the robot's onboard planning process. Results show that the resultant paths taken by the robot mimic expected human behaviour and can allow the robot to respond to altered human motion behaviours in the environment.

Paclitaxel resistance and multicellular spheroid formation are induced by kallikrein-related peptidase 4 in serous ovarian cancer cells in an ascites mimicking microenvironment

High tumor kallikrein-related-peptidase 4 (KLK4) levels are associated with a poor outcome for women with serous epithelial ovarian cancer (EOC), for which peritoneal dissemination and chemoresistance are key events. To determine the role of KLK4 in these events, we examined KLK4-transfected SKOV-3 and endogenous KLK4 expressing OVCA432 cells in 3-dimensional (3D) suspension culture to mimic the ascites microenvironment. KLK4-SKOV-3 cells formed multicellular aggregates (MCAs) as seen in ascites, as did SKOV-3 cells treated with active KLK4. MCA formation was reduced by treatment with a KLK4 blocking antibody or the selective active site KLK4 sunflower trypsin inhibitor (SFTI-FCQR). KLK4-MCAs formed larger cancer cell foci in mesothelial cell monolayers than those formed by vector and native SKOV-3 cells, suggesting KLK4-MCAs are highly invasive in the peritoneal microenvironment. A high level of KLK4 is expressed by ascitic EOC cells compared to matched primary tumor cells, further supporting its role in the ascitic microenvironment. Interestingly, KLK4 transfected SKOV-3 cells expressed high levels of the KLK4 substrate, urokinase plasminogen activator (uPA), particularly in 3D-suspension, and high levels of both KLK4 and uPA were observed in patient cells taken from ascites. Importantly, the KLK4-MCAs were paclitaxel resistant which was reversed by SFTI-FCQR and to a lesser degree by the general serine protease inhibitor, Aprotinin, suggesting that in addition to uPA, other as yet unidentified substrates of KLK4 must be involved. Nonetheless, these data suggest that KLK4 inhibition, in conjunction with paclitaxel, may improve the outcome for women with serous epithelial ovarian cancer and high KLK4 levels in their tumors.

The International regulation of persons displaced by climate change

It is certain that there will be changes in environmental conditions across the globe as a result of climate change. Such changes will require the building of biological, human and infrastructure resilience. In some instances the building of such resilience will be insufficient to deal with extreme changes in environmental conditions and legal frameworks will be required to provide recognition and support for people dislocated because of environmental change. Such dislocation may occur internally within the country of original origin or externally into another State’s territory. International and national legal frameworks do not currently recognise or assist people displaced as a result of environmental factors including displacement occurring as a result of climate change. Legal frameworks developed to deal with this issue will need to consider the legal rights of those people displaced and the legal responsibilities of those countries required to respond to such displacement. The objective of this article is to identify the most suitable international institution to host a program addressing climate displacement. There are a number of areas of international law that are relevant to climate displacement, including refugee law, human rights law and international environmental law. These regimes, however, were not designed to protect people relocating as a result of environmental change. As such, while they indirectly may be of relevance to climate displacement, they currently do nothing to directly address this complex issue. In order to determine the most appropriate institution to address and regulate climate displacement, it is imperative to consider issues of governance. This paper seeks to examine this issue and determine whether it is preferable to place climate displacement programs into existing international legal frameworks or whether it is necessary to regulate this area in an entirely new institution specifically designed to deal with the complex and cross-cutting issues surrounding the topic. Commentators in this area have proposed three different regulatory models for addressing climate displacement. These models include: (a) Expand the definition of refugee under the Refugee Convention to encompass persons displaced by climate change; (b) Implement a new stand alone Climate Displacement Convention; and (c) Implement a Climate Displacement Protocol to the UNFCCC. This article will examine each of these proposed models against a number of criteria to determine the model that is most likely to address the needs and requirements of people displaced by climate change. It will also identify the model that is likely to be most politically acceptable and realistic for those countries likely to attract responsibilities by its implementation. In order to assess whether the rights and needs of the people to be displaced are to be met, theories of procedural, distributive and remedial justice will be used to consider the equity of the proposed schemes. In order to consider the most politically palatable and realistic scheme, reference will be made to previous state practice and compliance with existing obligations in the area. It is suggested that the criteria identified by this article should underpin any future climate displacement instrument.

Creating 'saviour siblings' : the notion of harming by conceiving in the context of healthy children

Over the past decade there have been a number of families who have utilised assisted reproductive technologies (ARTs) to create a tissue-matched child, with the purpose of using the child’s tissue to cure an existing sick child. This inevitably brings such families a sense of hope as the ultimate aim is to overcome a family health crisis. However, this specific use of reproductive technologies has been the subject of significant criticism, most of which is levelled against the potential harm to the ‘saviour’ child. In Australia, families seeking to access reproductive technologies in this context are therefore required to justify their motives to an ethics committee in order to establish, amongst other things, whether the child will suffer harm once born. This paper explores the concept of harm in the context of conception, focusing on whether it is possible to ‘harm’ a healthy child who has been conceived to save another. To achieve this, the paper will evaluate the impact of the ‘non-identity’ principle in the ‘saviour sibling’ context, and assess the existing body of literature which addresses ‘harm’ in the context of conception. As will be established, the majority of such literature has focused on ‘wrongful life’ cases which seek to address whether an existing child who has been born with a disability, has been harmed. Finally, this paper will distinguish the harm arguments in the ‘saviour sibling’ context based on the fact that the harm evaluation concerns the ‘future-life’ assessment of a healthy child.

Academic wage structure by gender : the roles of peer review, performance, and market forces

We focus on understanding the role of productivity in determining wage structure differences between men and women in academia. The data arise from a pay-equity study carried out in a single Midwestern U.S. university over the 1996–7 academic year. Econometric results confirm that external market forces exert influence over both male and female salary. But peer review ratings play a significant role in male but not female earnings determination, with similar results for objective measures of research, teaching and service.