696 research outputs found

    Remote sensing of the Martian surface

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    Researchers investigated the physical properties of the Martian surface as inferred from a combination of orbiting and earth-based remote sensing observations and in-situ observations. This approach provides the most detailed and self-consistent view of the global and regional nature of the surface. Results focus on the areas of modeling the diurnal variation of the surface temperature of Mars, incorporating the effects of atmospheric radiation, with implications for the interpretation of surface thermal inertia; modeling the thermal emission from particulate surfaces, with application to observations of the surfaces of the Earth, Moon, and Mars; modeling the reflectance spectrum of Mars in an effort to understand the role of particle size in the difference between the bright and dark regions; and determining the slope properties of different terrestrial surfaces and comparing them with planetary slopes derived from radar observations

    Bioinspired Hard–Soft Interface Management for Superior Performance in Carbon Fibre Composites

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    Nature has evolved to create materials of unmatched performance governed by the interfacial interactions between hard and soft surfaces. Typically, in a carbon fibre composite, one polymer and one type of carbon fibre is used throughout a laminate. In this work, we use a carbon fibre surface modification approach to vary the fibre–matrix interface throughout the laminate to tailor the soft–hard interfaces. We demonstrate this effect using reclaimed carbon fibre materials in a thermoset polymer, then extend this concept to a thermoplastic polymer matrix–polypropylene. The thermoset specimens examined in this work consist of 5 carbon fibre plies, featuring 0, 1, 3 or 5 surface-modified layers located at the centre of the composite. The largest improvements in physical properties for these composites (yield strength, ultimate flexural strength, and tensile modulus) were found when only 1 modified layer of carbon fibre was placed directly within the centre of the composite. Subsequent investigations revealed that for a polypropylene matrix, where the surface chemistry is tailored specifically for polypropylene, improvements are also observed when mixed surface chemistries are used. This work shows that surface modification of reclaimed carbon fibres as non-woven mats can provide significant improvements in mechanical properties performance for structural composites when used in strategically advantageous locations throughout the composite

    From Offshore Operation to Onshore Simulator: Using Visualized Ethnographic Outcomes to Work with Systems Developers

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    This paper focuses on the process of translating insights from a Computer Supported Cooperative Work (CSCW)-based study, conducted on a vessel at sea, into a model that can assist systems developers working with simulators, which are used by vessel operators for training purposes on land. That is, the empirical study at sea brought about rich insights into cooperation, which is important for systems developers to know about and consider in their designs. In the paper, we establish a model that primarily consists of a ‘computational artifact’. The model is designed to support researchers working with systems developers. Drawing on marine examples, we focus on the translation process and investigate how the model serves to visualize work activities; how it addresses relations between technical and computational artifacts, as well as between functions in technical systems and functionalities in cooperative systems. In turn, we link design back to fieldwork studies

    The C. elegans tailless/Tlx homolog nhr-67 regulates a stage-specific program of linker cell migration in male gonadogenesis

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    Cell migration is a common event during organogenesis, yet little is known about how migration is temporally coordinated with organ development. We are investigating stage-specific programs of cell migration using the linker cell (LC), a migratory cell crucial for male gonadogenesis of C. elegans. During the L3 and L4 larval stages of wild-type males, the LC undergoes changes in its position along the migratory route, in transcriptional regulation of the unc-5 netrin receptor and zmp-1 zinc matrix metalloprotease, and in cell morphology. We have identified the tailless homolog nhr-67 as a cell-autonomous, stage-specific regulator of timing in LC migration programs. In nhr-67-deficient animals, each of the L3 and L4 stage changes is either severely delayed or never occurs, yet LC development before the early L3 stage or after the mid-L4 stage occurs with normal timing. We propose that there is a basal migration program utilized throughout LC migration that is modified by stage-specific regulators such as nhr-67

    "When you haven't got much of a voice": An evaluation of the quality of Independent Mental Health Advocate (IMHA) Services in England

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    Advocacy serves to promote the voice of service users, represent their interests and enable participation in decision-making. Given the context of increasing numbers of people detained under the Mental Health Act and heightened awareness of the potential for neglect and abuse in human services, statutory advocacy is an important safeguard supporting human rights and democratising the social relationships of care. This article reports findings from a national review of Independent Mental Health Advocate (IMHA) provision in England. A qualitative study used a two-stage design to define quality and assess the experience and impact of IMHA provision in eight study sites. A sample of 289 participants – 75 focus group participants and 214 individuals interviewed – including 90 people eligible for IMHA services, as well as advocates, a range of hospital and community-based mental health professionals, and commissioners. The research team included people with experience of compulsion. Findings indicate that the experience of compulsion can be profoundly disempowering, confirming the need for IMHA. However, access was highly variable and more problematic for people with specific needs relating to ethnicity, age and disability. Uptake of IMHA services was influenced by available resources, attitude and understanding of mental health professionals, as well as the organisation of IMHA provision. Access could be improved through a system of opt-out as opposed to opt-in. Service user satisfaction was most frequently reported in terms of positive experiences of the process of advocacy rather than tangible impacts on care and treatment under the Mental Health Act. IMHA has the potential to significantly shift the dynamic so that service users have more of a voice in their care and treatment. However, a shift is needed from a narrow conception of statutory advocacy as safeguarding rights to one emphasising self-determination and participation in decisions about care and treatment

    An Investigation Demonstrating the Feasibility of Microwave Sintering of Base-Metal-Electrode Multilayer Capacitors

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    Abstract. A microwave sintering technique has been developed for base-metal electrode (BME) multilayer ceramic capacitors (MLCCs). Commercial green chips of size 0603 MLC with nickel electrodes were sintered in a microwave field. With a specially designed susceptor/insulation package to optimize coupling and uniformity of heating, a number of sintering experiments were conducted in the temperature range of 1200 to 1250 • C in a multimode microwave cavity operating at 2.45 GHz under a partially reducing atmosphere. Microstructure of the microwave processed MLCCs was investigated with both SEM and TEM techniques. The dielectric properties of the microwave sintered MLCCs were measured and compared with those sintered using conventional process at 1320 • C and lower pO 2 's ≈ 10 −9 atms. The results demonstrate that nickel electrodes remain metallic after microwave sintering even though the pO 2 's were relatively high and would thermodynamically favor NiO. The microwave sintered samples showed a dense, fine and uniform microstructure. The properties of the microwavesintered samples were comparable to the conventionally sintered samples. The microwave processing was found to have enhanced sintering kinetics of the BME MLCCs, lowering sintering temperature by about 100 • C and also the processing time by about 90%

    Conflict of roles, a conflict of ideas? The unsettled relations between care team staff and independent mental health advocates.

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    Drawing on a national study of Independent Mental Health Advocacy we explore the social relations of independent advocacy. The study was commissioned by the Department of Health (England) and involved a case study design covering eight different geographies and service configurations, and interviews or focus groups with a total of 289 stakeholders across two phases of inquiry. This paper focuses on analysis of qualitative data relevant to the relationship between mental health care services and independent advocacy services, drawn from interviews with 214 participants in phase two of the study. Discussion of these particular findings affords insights into the working relations of independent advocacy within mental health services beset by reorganizational change and funding cuts, and increasing levels of legally sanctioned compulsion and coercion. We offer a matrix which accounts for the different types of working relationships that can arise and how these are associated with various levels of understanding of independent advocacy on the one hand, and appreciation for the value of advocacy on the other. The discussion is framed by the wider literature on advocacy and the claims by practitioners such as nurses for an advocacy role as part of their professional repertoire

    Investigating Variation in the Prevalence of Weathering in Faunal Assemblages in the UK: A Multivariate Statistical Approach

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    This article presents an exploratory multivariate statistical approach to gaining a more comprehensive understanding of variation in subaerial bone weathering in a British context. Weathering is among the most common taphonomic modifications and provides a crucial line of evidence for reconstructing the taphonomic trajectories of faunal assemblages and archaeological deposits. It provides clear evidence for prolonged subaerial exposure either before deposition in a context or because of later disturbance. In combination with other taphonomic indices such as gnawing, trampling, abrasion and fracture patterns, weathering can be used to reconstruct depositional histories and to investigate the structured treatment of different body parts or taxa in deposition. However, a broad range of factors affect the prevalence and severity of weathering, and therefore patterns can rarely be interpreted at face value. Many variables such as predepositional microenvironment cannot be traced archaeologically. Other contributory factors pertaining to the structural properties of elements and taxa can be discerned and must be taken into account in interpreting weathering signatures. However, disagreement exists regarding which variables are most important in mediating weathering. In addition for zooarchaeologists to interpret modification patterns, it is necessary for elements and taxa that are most likely to be affected by weathering to be defined. This is the case as deposits that are dominated by those classes of remains are likely to exhibit greater modification than those that are not, even if depositional histories were similar. Through a combination of classification tree and ordinal regression analysis, this article identifies which archaeologically recoverable variables explain the greatest variance in weathering and which anatomical elements and taxa are most likely to be affected in archaeological deposits in the UK

    Effect of tow size and interface interaction on interfacial shear strength determined by Iosipescu (V-Notch) testing in epoxy resin

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    Testing methodologies to accurately quantify interfacial shear strength (IFSS) are essential in order to understand fiber-matrix adhesion. While testing methods at a microscale (single filament fragmentation test-SFFT) and macroscale (Short Beam Shear-SBS) are wide spread, each have their own shortcomings. The Iosipescu (V-notch) tow test offers a mesoscale bridge between the microscale and macroscale whilst providing simple, accurate results with minimal time investment. However, the lack of investigations exploring testing variables has limited the application of Iosipescu testing to only a handful of studies. This paper assesses the effect of carbon fiber tow size within the Iosipescu tow test for epoxy resin. Tow sizes of 3, 6, and 9 k are eminently suitable, while more caution must be shown when examining 12, and 15 k tows. In this work, tows at 18 and 24 k demonstrated failure modes not derived from interfacial failure, but poor fiber wetting. A catalogue of common fracture geometries is discussed as a function of performance for the benefit of future researchers. Finally, a comparison of commercial (T300), amine (T300-Amine), and ethyl ester (T300-Ester) surface modified carbon fibers was conducted. The outcomes of this study showed that the Iosipescu tow test is inherently less sensitive in distinguishing between similar IFSS but provides a more \u27real world\u27 image of the carbon fiber-epoxy interface in a composite material

    Global Warming: Forecasts by Scientists versus Scientific Forecasts

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    In 2007, the Intergovernmental Panel on Climate Change’s Working Group One, a panel of experts established by the World Meteorological Organization and the United Nations Environment Programme, issued its Fourth Assessment Report. The Report included predictions of dramatic increases in average world temperatures over the next 92 years and serious harm resulting from the predicted temperature increases. Using forecasting principles as our guide we asked: Are these forecasts a good basis for developing public policy? Our answer is “no”. To provide forecasts of climate change that are useful for policy-making, one would need to forecast (1) global temperature, (2) the effects of any temperature changes, and (3) the effects of feasible alternative policies. Proper forecasts of all three are necessary for rational policy making. The IPCC WG1 Report was regarded as providing the most credible long-term forecasts of global average temperatures by 31 of the 51 scientists and others involved in forecasting climate change who responded to our survey. We found no references in the 1056-page Report to the primary sources of information on forecasting methods despite the fact these are conveniently available in books, articles, and websites. We audited the forecasting processes described in Chapter 8 of the IPCC’s WG1 Report to assess the extent to which they complied with forecasting principles. We found enough information to make judgments on 89 out of a total of 140 forecasting principles. The forecasting procedures that were described violated 72 principles. Many of the violations were, by themselves, critical. The forecasts in the Report were not the outcome of scientific procedures. In effect, they were the opinions of scientists transformed by mathematics and obscured by complex writing. Research on forecasting has shown that experts’ predictions are not useful in situations involving uncertainly and complexity. We have been unable to identify any scientific forecasts of global warming. Claims that the Earth will get warmer have no more credence than saying that it will get colder
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