Ultrasonic Guided Waves for Lap Splice Joint Inspection in Aging Aircraft

The integrity and reliability of adhesive joints in structural applications has long been a critical issue. Failure of these bonds during service could be catastrophic. In particular, the aviation industry due to its progressively aging fleet calls for a reliable non-destructive testing technique to characterize the bond quality. Several NDE techniques were developed each with its own advantages and disadvantages. [1–2] Utilization of ultrasonic guided waves offer a reliable and time efficient method. [3] Following several laboratory studies this technique was tested on a service damaged aircraft at Sandia National Laboratories in Albuquerque, NM. A Double Spring Hopping Probe (DSHP) was developed and tested on this test bed. A protocol for the inspection of lap splices and tear strap was established. The concepts of utilization of wave structure in mode selection, angle and frequency tuning for optimal use of the Lamb type guided waves are addressed. Highlights of our recent work on aging aircraft inspection are presented in this paper. The work expands on our earlier presentations. [4

Solid-state physics : a historic experiment redesigned

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Brendan meets Columbus: A more commodious islescape

This paper proposes that we can reimagine insular literatures and medieval islescapes as commodious seas of cultural and intellectual loci that span time, culture, and text alike. By moving beyond the rhetoric of insular separation or connectivity, we can see that islands connect even when medieval minds saw separation. The essay focuses on the Brendan legend and the commodious cultural ‘sea of islands’ that it inhabits, a space that connects the modern reader to a history of other connections, fact to fancy, and the real and the imaginary. When sailing in this sea, Brendan meets Columbus, and the late medieval idea of a lost island spreads though space and time

Identifying masked uncontrolled hypertension in the community pharmacy setting

© 2015 Wolters Kluwer Health, Inc. Masked uncontrolled hypertension (MUCH) is associated with an increased cardiovascular risk. This condition is frequent in the community pharmacy (i.e., CP-MUCH), but there is no evidence on the factors associated with its presence in that setting. The aim of this analysis was to explore these factors. A sample of 98 treated hypertensive patients from the MEPAFAR study, with normal community pharmacy blood pressure (CPBP <135/85 mmHg), were analyzed. Blood pressure (BP) was also measured at home (4 days) and monitored for 24 h. CP-MUCH was identified when either ambulatory (daytime) or home BP averages were equal to or higher than 135/85 mmHg. A multivariate logistic regression analysis was carried out to identify the factors associated with CP-MUCH. The prevalence of CP-MUCH tends to be higher as systolic and diastolic CPBP increase, reaching 47% in patients with both systolicand diastolic CPBP equal to or higher than 123 mmHg and 79 mmHg, respectively.The multivariate regression analysis showed only systolic CPBP as an independent factor of CP-MUCH [≥123 mmHg: odds ratio=16.46 (P=0.012); from 115 to 122.9 mmHg: odds ratio=10.74 (P=0.036); systolic CPBP <115 mmHg as the reference]. Further assessment, using ambulatory and/or home BP monitoring, is recommended in patients with normal CPBP, but systolic CPBP equal to or higher than 115 mmHg. A more feasible approach would be evaluating patients with systolic CPBP equal to or higher than 123 mmHg and diastolic CPBP equal to or higher than 79 mmHg

Spontaneous spin bifurcations and ferromagnetic phase transitions in a spinor exciton-polariton condensate

We observe a spontaneous parity breaking bifurcation to a ferromagnetic state in a spatially trapped exciton-polariton condensate. At a critical bifurcation density under nonresonant excitation, the whole condensate spontaneously magnetizes and randomly adopts one of two elliptically polarized (up to 95% circularly-polarized) states with opposite handedness of polarization. The magnetized condensate remains stable for many seconds at 5 K, but at higher temperatures it can flip from one magnetic orientation to another. We optically address these states and demonstrate the inversion of the magnetic state by resonantly injecting 100-fold weaker pulses of opposite spin. Theoretically, these phenomena can be well described as spontaneous symmetry breaking of the spin degree of freedom induced by different loss rates of the linear polarizations.This work was supported by Grants EPSRC No. EP/G060649/1, EU No. CLERMONT4 235114, EU No. INDEX 289968, Spanish MEC (MAT2008-01555), Greek GSRT ARISTEIA Apollo program and Fundación La Caixa, and Mexican CONACYT No. 251808. FP acknowledges financial support through an EPSRC doctoral prize fellowship at the University of Cambridge and a Schrödinger fellowship at the University of Oxford.This is the final version of the article. It first appeared from the American Physical Society via http://dx.doi.org/10.1103/PhysRevX.5.03100

The impact of a medication review with follow-up service on hospital admissions in aged polypharmacy patients

© 2016 The British Pharmacological Society Aims: The aims were to assess the impact of a medication review with follow-up (MRF) service provided in community pharmacy to aged polypharmacy patients on the number of medication-related hospital admissions and to estimate the effect on hospital costs. Methods: This was a sub-analysis of a cluster randomized controlled trials carried out in 178 community pharmacies in Spain. Pharmacies in the intervention group (IG) provided a comprehensive medication review during 6 months. Pharmacists in the comparison group (CG) delivered usual care. For the purposes of this sub-analysis, an expert panel of three internal medicine specialists screened the hospitalizations occurring during the main study, in order to identify medication-related hospitalizations. Inter-rater reliability was measured using Fleiss's kappa. Hospital costs were calculated using diagnosis related groups. Results: One thousand four hundred and three patients were included in the main study and they had 83 hospitalizations. Forty-two hospitalizations (50.6%) were medicine-related, with a substantial level of agreement among the experts (kappa = 0.65, 95% CI 0.52, 0.78, P < 0.01). The number of medication-related hospitalizations was significantly lower in patients receiving MRF (IG 11, GC 31, P = 0.042). The probability of being hospitalized was 3.7 times higher in the CG (odds ratio 3.7, 95% CI 1.2, 11.3, P = 0.021). Costs for a medicine-related hospitalization were €6672. Medication-related hospitalization costs were lower for patients receiving MRF [IG: €94 (SD 917); CG: €301 (SD 2102); 95% CI 35.9, 378.0, P = 0.018]. Conclusion: MRF provided by community pharmacists might be an effective strategy to balance the assurance of the benefit from medications and the avoidance of medication-related hospitalizations in aged patients using polypharmacy

Bond-length dependence of charge-transfer excitations and stretch phonon modes in perovskite ruthenates: Evidence of strong p – d hybridization effects

We reported the optical conductivity spectra of the Ruddlesden-Popper series ruthenates, i.e., Srn+1RunO3n+1 and Can+1RunO3n+1, where n=1, 2, and `. Among various optical transitions, we investigated two Ru-O related modes, i.e., the charge-transfer excitation and the transverse stretching phonon. We found that their frequency shifts are not much affected by a structural dimensionality, but are closely related to the Ru-O bond length. Through the quantitative analysis of the charge-transfer excitation energy, we could demonstrate that the p–d hybridization should play an important role in determining their electronic structure. In addition, we discussed how the electronic excitation could contribute the lattice dynamics in the metallic ruthenate

Electronic correlations in the iron pnictides

In correlated metals derived from Mott insulators, the motion of an electron is impeded by Coulomb repulsion due to other electrons. This phenomenon causes a substantial reduction in the electron's kinetic energy leading to remarkable experimental manifestations in optical spectroscopy. The high-Tc superconducting cuprates are perhaps the most studied examples of such correlated metals. The occurrence of high-Tc superconductivity in the iron pnictides puts a spotlight on the relevance of correlation effects in these materials. Here we present an infrared and optical study on single crystals of the iron pnictide superconductor LaFePO. We find clear evidence of electronic correlations in metallic LaFePO with the kinetic energy of the electrons reduced to half of that predicted by band theory of nearly free electrons. Hallmarks of strong electronic many-body effects reported here are important because the iron pnictides expose a new pathway towards a correlated electron state that does not explicitly involve the Mott transition.Comment: 10 page

Elevated CO₂ does not increase eucalypt forest productivity on a low-phosphorus soil

Rising atmospheric CO2 stimulates photosynthesis and productivity of forests, offsetting CO2 emissions. Elevated CO2 experiments in temperate planted forests yielded ~23% increases in productivity over the initial years. Whether similar CO2 stimulation occurs in mature evergreen broadleaved forests on low-phosphorus (P) soils is unknown, largely due to lack of experimental evidence. This knowledge gap creates major uncertainties in future climate projections as a large part of the tropics is P-limited. Here,we increased atmospheric CO2 concentration in a mature broadleaved evergreen eucalypt forest for three years, in the first large-scale experiment on a P-limited site. We show that tree growth and other aboveground productivity components did not significantly increase in response to elevated CO2 in three years, despite a sustained 19% increase in leaf photosynthesis. Moreover, tree growth in ambient CO2 was strongly P-limited and increased by ~35% with added phosphorus. The findings suggest that P availability may potentially constrain CO2-enhanced productivity in P-limited forests; hence, future atmospheric CO2 trajectories may be higher than predicted by some models. As a result, coupled climate-carbon models should incorporate both nitrogen and phosphorus limitations to vegetation productivity in estimating future carbon sinks