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High-entropy pyrochlore iridates A2Ir2O7 with multiple trivalent A cations were synthesized. The parent ternary A2Ir2O7 displays a variety of electronic phases depending on the size of A cations; Pr2Ir2O7 with a large A cation shows semimetallic behavior down to low temperatures, whereas A2Ir2O7 with smaller A cations, such as Nd2Ir2O7 and Eu2Ir2O7, displays a (semi)metal to magnetic insulator transition as a function of temperature. By further reducing the A cation size, smaller than Y3+, A2Ir2O7 becomes a Mott insulator, and long-range magnetic order takes place below room temperature. The metal–insulator transition and magnetic ordering turned out to be robust against strong disorder induced by the mixing of more than five A-cations in the high-entropy A2Ir2O7. The transition temperatures were found to scale with the average ionic radius of multiple A-cations. In contrast, high-entropy A2Ir2O7 including Bi3+ exhibits metallic behavior down to 2 K, which is likely associated with the presence of oxygen vacancies as in the parent Bi2Ir2O7. Although these indicate that the overall electronic structure of A2Ir2O7 remains intact in the presence of high-entropy configuration at the A-site, the transport properties suggest that fine details of the band structure may be modulated by local distortion. Strong disorder at the A-site of complex oxides may be exploited as a tool to control electronic properties. [ABSTRACT FROM AUTHOR]

Background: Injectable anaesthetic agents, topical creams and aqueous solutions have previously been used to anaesthetise the tympanic membrane for minor ear procedures. Topical creams take 20–30 minutes to work and injectable anaesthetics can cause canal swelling. The effectiveness of lidocaine spray has not previously been investigated in patients undergoing minor ear procedures. Methods: Eighteen participants attending for out-patient grommet insertion or intratympanic steroid injection were prospectively recruited for this study over six months. Post-operatively, they were asked about their perceived level of pain and overall experience. Results: The median level of pain measured on an 11-point visual analogue scale was 2 out of 10. Forty-four per cent reported the overall experience as pleasant, with the remainder selecting slightly unpleasant (66 per cent). All participants stated they would undergo the procedure again. Conclusion: Xylocaine spray is simple to administer, rapid-acting and well tolerated by patients for anaesthesia of the tympanic membrane during minor ear procedures in the out-patient setting. [ABSTRACT FROM AUTHOR]

The recently-discovered high pressure material MnFe3O5 displays a rich variety of magnetically ordered states on cooling. Fe spins order antiferromagnetically below a Néel transition at 350 K. A second transition at 150 K marks Mn spin order that leads to spin canting of some of the Fe spins and ferrimagnetism. A further transition at 60 K is driven by charge ordering of Fe2+ and Fe3+ over two inequivalent Fe sites, with further canting of all spins. Electrical resistivity measurements reveal semiconducting behaviour in MnFe3O5 with a change in activation energy at 285 K. [ABSTRACT FROM AUTHOR]

To be uncertain is to be unsure or have doubt. Results from a random sample survey show the majority (89.5%) of farmers in the Upper Midwest perceived there was too much uncertainty about the impacts of climate to justify changing their agricultural practices and strategies, despite scientific evidence regarding the causes and potential consequences of climate change. This study uses random sample survey data (n = 4,778) and in-depth interviews (n = 159) of Upper Midwest farmers to better understand factors that underlie their uncertainty and reluctance to take adaptive action. Results reveal that farmers' uncertainty about projected climate change impacts on their production systems is influenced by their beliefs about climate change, experiences with drought, concern about heat stress on crops, and agricultural information networks. Findings suggest a combination of insufficient information and normative influences on climate beliefs are influencing farmer uncertainty. In cases where uncertainty is caused by insufficient information, improved farmer access to and use of historical crop and local climate records, as well as decision support tools that simulate different climate scenarios and their impacts on production, could improve estimates of future risks. However, more information may be insufficient to address claims of uncertainty when differing political and cultural norms contest the parameters of climate change. This suggests that scientific knowledge must be linked to social values and beliefs and trusted agricultural networks for widespread adaptive management to a changing climate to occur. [ABSTRACT FROM AUTHOR]

Cover crops are widely viewed by the soil and water conservation community to be an effective means for reducing soil erosion and nutrient loss and increasing soil health, yet relatively few farmers have adopted the practice. Despite the widespread recognition of cover crops' benefits and increased promotional efforts, there have been very few peer-reviewed studies focused on farmer perspectives on or adoption of cover crops. This study, which analyzed data from a survey and in-depth interviews with Iowa farmers, examined the roles that perceived practice characteristics, perspectives on potential facilitating factors, and crop and livestock diversity play in cover crop adoption among Iowa farmers. As expected, perceived benefits were strongly associated with cover crop use. Measures of crop and livestock diversity were also positive predictors of adoption. In addition, farmers who endorsed strengthening of facilitating factors such as educational and technological infrastructure to support cover crop use were more likely to have adopted cover crops. Farmers who perceived higher levels of risks associated with cover crop use, on the other hand, were less likely to use them. Results suggest that research and promotional efforts should focus on both raising awareness of potential benefits and quantifying and communicating potential risks and risk abatement strategies. Helping farmers to better understand (1) the benefits of cover crops and how they can be enhanced, and (2) the potential risks and ways that they can be minimized might allow farmers to more effectively weigh the probable benefits and costs of cover crop use. The findings further suggest that farmers believe that better facilitating infrastructure, in the form of technical assistance (e.g., agricultural retailers and custom operators) and education, is needed to support the widespread adoption of cover crops. [ABSTRACT FROM AUTHOR]

This paper attempts to relate the lithology and fabric of four main groups of Newcastle Coal Measures rock types to their geotechnical properties and engineering behaviour. The four groups comprise: massive sandstone and conglomerate; claystones and tuffs; mudstone, shale and siltstone; and the coal itself. Although their geological relevance is primarily concerned with underground coal mining, these rocks are exposed at the surface across most of Newcastle and its suburbs, and are thus significant in terms of urban environmental geology. The key mining issues include longwall support design and panel layouts, caving and subsidence mechanisms, soft floors and stiff roofs, water inflows and pillar design. The urban geotechnical issues include landslides and rock falls, shallow abandoned mine workings, reactive and erodible soils, waste disposal and potential sources for geomaterials. [ABSTRACT FROM PUBLISHER]

This paper examines the issues associated with the real-time measurement of viscosity in a single-screw extruder. To this end, the static and dynamic performance of a side-stream and in-line rheometer are compared. Side-stream sampling techniques were shown to be inappropriate for accurate detection of process dynamics. In-line rheometers may detect process dynamics but there are practical limitations on their use in an industrial environment. [ABSTRACT FROM AUTHOR]

Polyamide 6, polyamide 12, polybutyleneterephthalate, and polyetherimide films are plasma treated in an APGD unit using various applied voltages, gas flow rates, frequencies, and dwell times. The results show changes in the surface chemistry (FTIR); the degree of change in dynamic contact angle is found to be dependent on the polymer type, dwell time, and electrical characteristics of the plasma. [ABSTRACT FROM AUTHOR]

The effect of molecular weight on the migratory characteristics of polyisobutylene (PIB) additive from the bulk to the surface of a range of monolayer and multilayer extruded polyethylene films has been analyzed by FTIR-ATR and peel cling analysis. Migration rates are shown to be higher for lower molecular weight PIB additive, and cling strength increases as the PIB molecular weight increases. [ABSTRACT FROM AUTHOR]

A range of EVA-mLLDPE-EVA coextruded films, with polyisobutylene (PIB) masterbatch content of 0-20% and vinyl acetate (VA) comonomer content of 6, 12, and 18%, is manufactured. The films are aged at 45°C for up to 28 days to enable tack (cling) development. The results show that film tack strength improves significantly with aging. Increased VA concentration in the surface layer also shows significant improvement in film tack strength. The film tensile strength, elongation, and tear properties in both machine direction (MD) and transverse direction (TD) are not significantly affected by increase in PIB concentration. Increased VA content shows slight improvement in MD mechanical performance of the films, although TD properties are relatively unaffected. [ABSTRACT FROM AUTHOR]

Polyethylene films, prepared from a range of mLLDPE, LLDPE, and ULDPE resins containing 4% polyisobutylene (PIB) from a masterbatch, are manufactured using a Killion cast film extrusion system. FTIR, DSC, and mechanical analysis techniques are used to investigate the effect of comonomer type, density, and melt flow index (MFI) on the mechanical performance, orientation, and crystallinity of these films. The study established that comonomer type and MFI are the greatest factors influencing the mechanical performance of crystallinity. Crystallinity has been found to be the most influential factor governing PIB migration in these films and this in turn is related to polymer type, density, and MFI. [ABSTRACT FROM AUTHOR]

Examines polyolefin-organoclay nanocomposites containing a synthetic tetrasilisic fluoromica. Preparation of the nanocomposites from metallocene-catalyzed and conventional Ziegler-Natta-catalyzed linear low-density polyethylenes; Effects of maleic-anhydride grafted compatibilizer; Crystallization; Dynamic mechanical thermal analysis.

With the advent of more stringent legislation for fuel and fuel vapor emissions from vehicles, it has been necessary to introduce a barrier polymer into the fuel line as a means of reducing emissions. This paper investigates the changes in mechanical properties, such as tensile modulus, of a range of plasticized nylons, tie layer polymer systems and fluoropolymers which were immersed in various mixtures of fuel components and standard fuels at a temperature of 250C. The percentage mass uptake and extent of swelling were also determined in addition to changes in glass transition temperature up to a period of 31 weeks. [ABSTRACT FROM PUBLISHER]

Porcellanite is a siliceous duricrust which has developed within altered Cretaceous mudrocks in the Darwin city area and is well exposed in coastal cliffs to the north. Its distinctive geotechnical properties include low bulk density, variable strength that is highly dependent on moisture content, and relatively high (but inconsistent) durability. The porcellanite rock mass is inhomogeneous and anisotropic; it is unrippable at the surface, but becomes weaker with depth. It is also highly permeable in places, even karst-like, due to solution cavities. These characteristics are common to all duricrusts and result from processes of solution, replacement and redeposition by silica-laden groundwater. Such processes may have been intermittently active through most of the Cenozoic and there is evidence that they continue to the present. The upper 2–4 m of the porcellanite profile is made up of a brittle, high-strength rock with a silica content approaching that of silcrete. The underlying altered and porous siltstone is much weaker and deforms plastically under loading, due to a cellular microfabric composed largely of opaline silica replacing clay minerals. Porcellanite has long been used as the main building stone in Darwin and is now quarried for shoreline filling. Although some of it is of select fill or road sub-base quality, crushed porcellanite contains an excess of plastic fines making it unsuitable for basecourse. Porcellanite has been a failure as breakwater stone, despite producing blocks of adequate size. [ABSTRACT FROM AUTHOR]

The former Northern Coalfield, comprising much of the Newcastle–Maitland–Cessnock–Lake Macquarie region, has now been mined for two hundred years. Most of the twenty-odd seams in the Newcastle, Tomago and Greta Coal Measures have been worked, but the bulk of production has been drawn from just four coalbeds: the Borehole, Greta, Homeville and Great Northern Seams. Literally hundreds of mine names are on record for the coalfield, the great majority working these seams at depths of less than 30 m. This paper reviews regional subsidence problems in the context of mining history, past mining practices and coal measures geology. Subsidence over shallow bord-and-pillar workings may result in highly disturbed ground, open fissures, cratering, seam fires and ‘creeps’ (slow surface movements caused by gradual closure of mine cavities). This form of subsidence differs from that over modern longwall mines in being less predictable, affecting much smaller areas, and occurring sometimes decades after mine abandonment. The geological factors contributing to this subsidence hazard include the multiplicity of seams, the strong roof sandstones, stiff coal and relatively soft floors, and the presence of faults and dykes. The working of thick seams like the Borehole Coal in up to three phases, leaving high, slender pillars, also contributed to later ground instability. Contrary to expectation, the main problem areas are not over haphazardly laid-out convict-era pits, but rather above small hand-worked scavenger mines (‘ratholes’) which operated as late as the 1950s. Many of these short-lived collieries still contain large voids at shallow depth, sometimes only a few metres, which must eventually collapse or be backfilled. [ABSTRACT FROM AUTHOR]

Bitumen, a mixture of aromatics, paraffins, asphaltenes and resins that remain after crude oil has been fractionally distilled, finds applications in blends with a proportion of a polymer, in built up membranes for the roofing industry. Blends of three commercially used polymers with a 100 penetration grade Nynas bitumen at levels between 9% and 29% w/w were prepared using a Z-blade mixer. The morphology, thermal and dynamic mechanical properties of these blends were examined using fluorescence optical microscopy, differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The blends prepared with these polymers displayed low temperature flexibility and an onset of flow at high temperatures. The former characteristic is required for use in cold environments the latter feature being a critical property when the membrane is manufactured and later when applied by the torching process on a roof. It may be seen how the different blends function in a manner that makes them suitable for the production of built-up roofing membranes. [ABSTRACT FROM PUBLISHER]

As Metallocene Catalysed Polyethylenes (mPEs) become more commercially available they are finding ever increasing application in the blown film industry. However, it is becoming apparent that no two mPE resins behave in exactly the same manner. This paper examines the Theological properties of a range of mPEs with different densities and MFIs. These resins were then blended with a conventional low density polyethylene (LDPE) and extruded to form monolayer films. The mechanical properties of these films were compared to three layer coextruded films of A:B:A structure, where A is LDPE and B is mPE. [ABSTRACT FROM PUBLISHER]

An account is given of an investigation into the peel strength of wool fabrics bonded with different compositions of vinyl acetate-ethylene copolymer latices for which a 180° peel-testing method was used. The effects on the bond strength of changes in viscosity, thickness, contact time, contact pressure, and method of application of the adhesive are also examined. Modifications to the surface of the wool fibre were found to have a significant effect on the bond strength, as did the effective area of the superimposed fabrics. [ABSTRACT FROM AUTHOR]