938 research outputs found

    Energy efficient engine. Fan and quarter-stage component performance report

    Get PDF
    The fan configuration for the general Electric/NASA Energy Efficient Engine was selected following an extensive preliminary design study. The fan has an inlet radius ratio of 0.342 and a specific flowrate of 208.9 Kg/sec/sq. m (42.8 1bm/sec/sq. ft). The design corrected tip speed is 411.5 m/sec (1350 ft/sec) producing a bypass flow total-pressure ratio of 1.65 and a core flow total-pressure ratio of 1.6. The design bypass ratio is 6.8. The aerodynamic design point corresponds to the maximum climb power setting at Mach 0.8 and 10.67 Km (35,000 ft) altitude. The fully-instrumented fan component was tested in the Lynn Large Fan Test Facility in 1981. The overall performance results, reported herein, showed excellent fan performance with the fan meeting all of its component test goals of flow, efficiency and stall margin

    A simple method for the determination of refractive indices of (rough) transparent solids

    Get PDF
    Simple methods for the determination of refractive indices of transparent polymers and inorganic and organic solids of irregular geometry or with scratched or corrugated surfaces are rare. A classical procedure is based on the invisibility of a body immersed in a liquid with the same refractive index as that of the body. In order to avoid the laborious procedure connected with the search for a liquid with matching refractive index and to find an approach which is independent of the observation by eye, we describe here a modified immersion method which allows the ready determination of the refractive index of solids. The present method is based on the interpolation of the maximum transmission (nTmax) of a solid immersed in liquids with different, typically non-matching, refractive indices. Illustrations with quartz glass, crown glass and poly(vinylidene fluoride) (PVDF) films showed that nTmax can be determined with a reproducibility of ± 0.003. By comparison with refractive indices determined by ellipsometry, it was concluded that the refractive index of a solid can be determined with the modified immersion method within an accuracy better than ± 0.01 when systematic errors resulting from the fit method are also taken into consideratio

    The Physicist's Guide to the Orchestra

    Get PDF
    An experimental study of strings, woodwinds (organ pipe, flute, clarinet, saxophone and recorder), and the voice was undertaken to illustrate the basic principles of sound production in music instruments. The setup used is simple and consists of common laboratory equipment. Although the canonical examples (standing wave on a string, in an open and closed pipe) are easily reproduced, they fail to explain the majority of the measurements. The reasons for these deviations are outlined and discussed.Comment: 11 pages, 10 figures (jpg files). Submitted to European Journal of Physic

    Detection of optimal PEEP for equal distribution of tidal volume by volumetric capnography and electrical impedance tomography during decreasing levels of PEEP in post cardiac-surgery patients

    Get PDF
    Background Homogeneous ventilation is important for prevention of ventilator-induced lung injury. Electrical impedance tomography (EIT) has been used to identify optimal PEEP by detection of homogenous ventilation in non-dependent and dependent lung regions. We aimed to compare the ability of volumetric capnography and EIT in detecting homogenous ventilation between these lung regions. Methods Fiftee

    The phylogenetically-related pattern recognition receptors EFR and XA21 recruit similar immune signaling components in monocots and dicots

    Get PDF
    During plant immunity, surface-localized pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs). The transfer of PRRs between plant species is a promising strategy for engineering broad-spectrum disease resistance. Thus, there is a great interest in understanding the mechanisms of PRR-mediated resistance across different plant species. Two well-characterized plant PRRs are the leucine-rich repeat receptor kinases (LRR-RKs) EFR and XA21 from Arabidopsis thaliana (Arabidopsis) and rice, respectively. Interestingly, despite being evolutionary distant, EFR and XA21 are phylogenetically closely related and are both members of the sub-family XII of LRR-RKs that contains numerous potential PRRs. Here, we compared the ability of these related PRRs to engage immune signaling across the monocots-dicots taxonomic divide. Using chimera between Arabidopsis EFR and rice XA21, we show that the kinase domain of the rice XA21 is functional in triggering elf18-induced signaling and quantitative immunity to the bacteria Pseudomonas syringae pv. tomato (Pto) DC3000 and Agrobacterium tumefaciens in Arabidopsis. Furthermore, the EFR:XA21 chimera associates dynamically in a ligand-dependent manner with known components of the EFR complex. Conversely, EFR associates with Arabidopsis orthologues of rice XA21-interacting proteins, which appear to be involved in EFR-mediated signaling and immunity in Arabidopsis. Our work indicates the overall functional conservation of immune components acting downstream of distinct LRR-RK-type PRRs between monocots and dicots

    Meneco, a Topology-Based Gap-Filling Tool Applicable to Degraded Genome-Wide Metabolic Networks

    Get PDF
    International audienceIncreasing amounts of sequence data are becoming available for a wide range of non-model organisms. Investigating and modelling the metabolic behaviour of those organisms is highly relevant to understand their biology and ecology. As sequences are often incomplete and poorly annotated, draft networks of their metabolism largely suffer from incompleteness. Appropriate gap-filling methods to identify and add missing reactions are therefore required to address this issue. However, current tools rely on phenotypic or taxonomic information, or are very sensitive to the stoichiometric balance of metabolic reactions, especially concerning the co-factors. This type of information is often not available or at least prone to errors for newly-explored organisms. Here we introduce Meneco, a tool dedicated to the topological gap-filling of genome-scale draft metabolic networks. Meneco reformulates gap-filling as a qualitative combinatorial optimization problem, omitting constraints raised by the stoichiometry of a metabolic network considered in other methods, and solves this problem using Answer Set Programming. Run on several artificial test sets gathering 10,800 degraded Escherichia coli networks Meneco was able to efficiently identify essential reactions missing in networks at high degradation rates, outperforming the stoichiometry-based tools in scalability. To demonstrate the utility of Meneco we applied it to two case studies. Its application to recent metabolic networks reconstructed for the brown algal model Ectocarpus siliculosus and an associated bacterium Candidatus Phaeomarinobacter ectocarpi revealed several candidate metabolic pathways for algal-bacterial interactions. Then Meneco was used to reconstruct, from transcriptomic and metabolomic data, the first metabolic network for the microalga Euglena mutabilis. These two case studies show that Meneco is a versatile tool to complete draft genome-scale metabolic networks produced from heterogeneous data, and to suggest relevant reactions that explain the metabolic capacity of a biological system

    Support and Assessment for Fall Emergency Referrals (SAFER) 2: a cluster randomised trial and systematic review of clinical effectiveness and cost-effectiveness of new protocols for emergency ambulance paramedics to assess older people following a fall with referral to community-based care when appropriate.

    Get PDF
    BACKGROUND: Emergency calls are frequently made to ambulance services for older people who have fallen, but ambulance crews often leave patients at the scene without any ongoing care. We evaluated a new clinical protocol which allowed paramedics to assess older people who had fallen and, if appropriate, refer them to community-based falls services. OBJECTIVES: To compare outcomes, processes and costs of care between intervention and control groups; and to understand factors which facilitate or hinder use. DESIGN: Cluster randomised controlled trial. PARTICIPANTS: Participating paramedics at three ambulance services in England and Wales were based at stations randomised to intervention or control arms. Participants were aged 65 years and over, attended by a study paramedic for a fall-related emergency service call, and resident in the trial catchment areas. INTERVENTIONS: Intervention paramedics received a clinical protocol with referral pathway, training and support to change practice. Control paramedics continued practice as normal. OUTCOMES: The primary outcome comprised subsequent emergency health-care contacts (emergency admissions, emergency department attendances, emergency service calls) or death at 1 month and 6 months. Secondary outcomes included pathway of care, ambulance service operational indicators, self-reported outcomes and costs of care. Those assessing outcomes remained blinded to group allocation. RESULTS: Across sites, 3073 eligible patients attended by 105 paramedics from 14 ambulance stations were randomly allocated to the intervention group, and 2841 eligible patients attended by 110 paramedics from 11 stations were randomly allocated to the control group. After excluding dissenting and unmatched patients, 2391 intervention group patients and 2264 control group patients were included in primary outcome analyses. We did not find an effect on our overall primary outcome at 1 month or 6 months. However, further emergency service calls were reduced at both 1 month and 6 months; a smaller proportion of patients had made further emergency service calls at 1 month (18.5% vs. 21.8%) and the rate per patient-day at risk at 6 months was lower in the intervention group (0.013 vs. 0.017). Rate of conveyance to emergency department at index incident was similar between groups. Eight per cent of trial eligible patients in the intervention arm were referred to falls services by attending paramedics, compared with 1% in the control arm. The proportion of patients left at scene without further care was lower in the intervention group than in the control group (22.6% vs. 30.3%). We found no differences in duration of episode of care or job cycle. No adverse events were reported. Mean cost of the intervention was £17.30 per patient. There were no significant differences in mean resource utilisation, utilities at 1 month or 6 months or quality-adjusted life-years. In total, 58 patients, 25 paramedics and 31 stakeholders participated in focus groups or interviews. Patients were very satisfied with assessments carried out by paramedics. Paramedics reported that the intervention had increased their confidence to leave patients at home, but barriers to referral included patients' social situations and autonomy. CONCLUSIONS: Findings indicate that this new pathway may be introduced by ambulance services at modest cost, without risk of harm and with some reductions in further emergency calls. However, we did not find evidence of improved health outcomes or reductions in overall NHS emergency workload. Further research is necessary to understand issues in implementation, the costs and benefits of e-trials and the performance of the modified Falls Efficacy Scale. TRIAL REGISTRATION: Current Controlled Trials ISRCTN60481756 and PROSPERO CRD42013006418. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 13. See the NIHR Journals Library website for further project information
    corecore