541 research outputs found

    Size distributions in multistage crystallization

    Get PDF

    The influence of heating and cooling rates on TBC failure in high heat flux tests

    Get PDF
    High heat flux testing is a commonly used procedure to investigate TBC failure modes. Samples of TBC on superalloy are thermally cycled, with the TBC being heated and the superalloy subjected to forced cooling in order to induce a temperature gradient. Typically conditions are deliberately chosen to be more aggressive than in the engine in order to induce TBC delamination or complete spallation within a few days. We have developed a test bench with a CO2 laser as the heat source which, unlike the more commonly used burner rigs, allows exquisite control of the heating and cooling rates. An optical system detects the hot spots which are caused by TBC delamination. We experimentally validate a two-phase model for TBC failure. In Phase I a vertical crack is driven from the TBC surface down towards the bond coat, which requires a sufficiently high cooling rate. This acts as a starting defect for Phase II, in which a horizontal crack propagates and causes delamination / spallation, which requires a sufficiently high heating rate. In general, we find that heating and cooling rates are a more useful tool to probe TBC robustness than surface temperature or number of thermal cycles

    Application of a Split Luciferase Complementation Assay for theDetection of Viral Protein-Protein Interactions

    Get PDF
    Intraviral protein-protein interactions are critical for virus survival in the host. Discovery of such interactions is important to understand molecular mechanisms of viral replication and pathogenesis. The development of a cell-based assay that can be employed to examine systematically viral protein interactions is described. The method, known as the Split Luciferase Complementation Assay (SLCA), is based on the principle that N- and C-terminal domains of luciferase alone do not emit luminescence; however, if fused to interacting proteins the two nonfunctional halves can be brought into close enough proximity through a specific protein-protein interaction to restore the functions of the enzyme and emit detectable light. The well-studied influenza B polymerase acidic protein (PA) and basic protein 1 (PB1) interaction was used as a model system to develop the assay. Consistent with previous studies, a strong PA-PB1 interaction was demonstrated in the assay. The PA-PB1 interaction was also disrupted by single amino acid mutations in the N-terminal domain of PB1 that is responsible for binding PA. The described SLCA is highly specific and easy to perform, and thus may be useful for studying protein-protein interactions in viral diseases

    Non-linear interaction modulates global extreme sea levels, coastal flood exposure, and impacts

    Get PDF
    We introduce a novel approach to statistically assess the non-linear interaction of tide and non-tidal residual in order to quantify its contribution to extreme sea levels and hence its role in modulating coastal protection levels, globally. We demonstrate that extreme sea levels are up to 30% (or 70 cm) higher if non-linear interactions are not accounted for (e.g., by independently adding astronomical and non-astronomical components, as is often done in impact case studies). These overestimates are similar to recent sea-level rise projections to 2100 at some locations. Furthermore, we further find evidence for changes in this non-linear interaction over time, which has the potential for counteracting the increasing flood risk associated with sea-level rise and tidal and/or meteorological changes alone. Finally, we show how accounting for non-linearity in coastal impact assessment modulates coastal exposure, reducing recent estimates of global coastal flood costs by ~16%, and population affected by ~8%

    More individual differences in language attainment: How much do adult native speakers of English know about passives and quantifiers?

    Get PDF
    This paper provides experimental evidence suggesting that there are considerable differences in native language attainment, and that these are at least partially attributable to individual speakers’ experience. Experiment 1 tested high academic attainment (hereafter, HAA) and low academic attainment (LAA) participants’ comprehension using a picture selection task. Test sentences comprised passives and two variants of the universal quantification construction. Active constructions were used as a control condition. HAA participants performed at ceiling in all conditions; LAA participants performed at ceiling only on actives. As predicted by usage-based accounts, the order of difficulty of the four sentence types mirrored their frequency. Experiment 2 tested whether the less-educated participants’ difficulties with these constructions are attributable to insufficient experience. After a screening test, low scoring participants were randomly assigned to two training groups. The passive training group were given a short training session on the passive construction; and the quantifier training group were trained on sentences with quantifiers. A series of post-training tests show that performance on the trained construction improved dramatically, and that the effect was long-lasting

    Vertical structure of Sb-intercalated quasi-freestanding graphene on SiC(0001)

    Full text link
    Using the normal incidence x-ray standing wave technique as well as low energy electron microscopy we have investigated the structure of quasi-freestanding monolayer graphene (QFMLG) obtained by intercalation of antimony under the (63×63)R30∘(6\sqrt{3}\times6\sqrt{3})R30^\circ reconstructed graphitized 6H-SiC(0001) surface, also known as zeroth-layer graphene. We found that Sb intercalation decouples the QFMLG very well from the substrate. The distance from the QFMLG to the Sb layer almost equals the expected van der Waals bonding distance of C and Sb. The Sb intercalation layer itself is mono-atomic, very flat, and located much closer to the substrate, at almost the distance of a covalent Sb-Si bond length. All data is consistent with Sb located on top of the uppermost Si atoms of the SiC bulk

    Record media used by primary care providers in medically underserved regions of upstate New York was not pivotal to clinical result in the Informatics for Diabetes Education and Telemedicine (IDEATel) project

    Get PDF
    Purpose To examine integration of electronic medical records (EMRs) by primary care providers (PCPs) in a diabetes telemedicine project (IDEATel) in medically underserved rural areas and assess if access to digital records is associated with diabetes intermediate outcomes. Method PCPs (n=61) with patients in IDEATel participated in structured interviews to determine current (2006 to 2007) and projected (2007 to 2008) use of paper and/or electronic medical data. T-tests examined group differences. Results 28% (17/61) of PCPs had comprehensive EMRs, but most electronic data were noninteroperative between offices; 6% of PCPs solely used paper; 92% of PCPs used mixed paper/electronic records. Half of 61 PCPs anticipated no migration within one year to an electronic record for common patient data, while one third anticipated that function would become greatly more electronic. Among 31 PCPs interviewed in depth in person, 70% (7/10) in private practice and 69% (9/13) in networks anticipated greater electronic media migration through system change, whereas 100% of responding academic PCPs (n=6) expected only system modifications. PCPs were most interested in data exchange for chronic disease management (94%), regional benchmarking (84%) and quality improvement (87%). Patient personal electronic health records were rarely mentioned. IDEATel patients of PCPs with or without access to comprehensive EMRs achieved similar haemoglobin A1c, blood pressure, LDL-cholesterol, and body mass index, but the small number invokes cautious interpretation. Conclusions Our findings suggest an effective and complementary element of national health information technology (HIT) strategy, telemedicine, can be implemented by PCPs with success despite the lack of a concurrent EMR for efficient data exchange
    • …
    corecore