Non-Destructive Inspection of Impact Damage in Composite Aircraft Panels by Ultrasonic Guided Waves and Statistical Processing.

This paper discusses a non-destructive evaluation (NDE) technique for the detection of damage in composite aircraft structures following high energy wide area blunt impact (HEWABI) from ground service equipment (GSE), such as heavy cargo loaders and other heavy equipment. The test structures typically include skin, co-cured stringers, and C-frames that are bolt-connected onto the skin with shear ties. The inspection exploits the waveguide geometry of these structures by utilizing ultrasonic guided waves and a line scan approach. Both a contact prototype and a non-contact prototype were developed and tested on realistic test panels subjected to impact in the laboratory. The results are presented in terms of receiver operating characteristic curves that show excellent probability of detection with low false alarm rates for defects located in the panel skin and stringers

2017 Trade Finance Gaps, Growth and Jobs Survey

Key Points • The global trade finance gap is estimated at $1.5 trillion. • 40% of the gap originates in Asia and the Pacific. • 74% of rejected trade finance transactions come from SMEs and midcap firms. • Female-owned firms report higher rejection rates, and are less likely to find alternatives in the formal financial sector. • At least 36% of rejected trade finance may be fundable by other financial institutions. • A 10% increase in trade finance could boost employment by 1%. • 80% of banks report digitization will cut costs, yet no evidence that savings translate to tional trade finance apacity

Bypassing state initialization in Hamiltonian tomography on spin-chains

We provide an extensive discussion on a scheme for Hamiltonian tomography of a spin-chain model that does not require state initialization [Phys. Rev. Lett. 102, 187203 (2009)]. The method has spurred the attention of the physics community interested in indirect acquisition of information on the dynamics of quantum many-body systems and represents a genuine instance of a control-limited quantum protocol.Comment: 7 pages, 2 figures, RevTeX

Can an established preschool obesity prevention programme (HENRY) be successfully delivered by trained volunteers?

Abstract IntroductionAlmost a quarter of 4-5 year olds are overweight. HENRY (Health, Exercise, Nutrition for the Really Young) delivers evidence-based interventions with consistently positive results when delivered by trained staff. This study tested whether this intervention could also be successfully delivered by trained volunteers.MethodThe programme was delivered one-to-one over eight 1-hour sessions. Baseline and post programme data was analysed for 87 parents and, for a sub-sample, at 6 months follow-up. Delivery was at the parent's home or community venue according to parent preference in four London boroughs. Approximately 80% of programmes were delivered by volunteers with a similar demographic profile to target parents and 20% by staff to enable a comparative evaluation.ResultsProgrammes provided by volunteers and staff showed similar statistically significant improvements in self-reported parent and child emotional wellbeing, parenting efficacy, and fruit and vegetable consumption. Additional benefits were seen in family eating (e.g. eating healthy meals and eating with others) and food purchasing (e.g. reading labels on food packaging) behaviours. Follow-up data showed that some changes were maintained six months later. Parent and volunteer ratings of the programme and training were very positive, with high retention (mean attendance of 7.2 out of 8 sessions).ConclusionVolunteers from similar backgrounds to target families can be recruited and trained to deliver structured obesity prevention programmes, resulting in the same positive lifestyle changes as those delivered by paid staff. External funding details Department of Health: Health and Social Care Volunteering Fund grant (Ref: 2013/National/055).Peer reviewe

Free boundary problems for Tumor Growth: a Viscosity solutions approach

The mathematical modeling of tumor growth leads to singular stiff pressure law limits for porous medium equations with a source term. Such asymptotic problems give rise to free boundaries, which, in the absence of active motion, are generalized Hele-Shaw flows. In this note we use viscosity solutions methods to study limits for porous medium-type equations with active motion. We prove the uniform convergence of the density under fairly general assumptions on the initial data, thus improving existing results. We also obtain some additional information/regularity about the propagating interfaces, which, in view of the discontinuities, can nucleate and, thus, change topological type. The main tool is the construction of local, smooth, radial solutions which serve as barriers for the existence and uniqueness results as well as to quantify the speed of propagation of the free boundary propagation

Nested entangled states for distributed quantum channels

We find a coupling-strength configuration for a linear chain of N spins which gives rise to simultaneous multiple Bell states. We suggest a way such an interesting entanglement pattern can be used in order to distribute maximally entangled channels to remote locations and generate multipartite entanglement with a minimum-control approach. Our proposal thus provides a way to achieve the core resources in distributed information processing. The schemes we describe can be efficiently tested in chains of coupled cavities interacting with three-level atoms.Comment: 4 pages, 2 figures, RevTeX

Atomic-Scale Dynamics of the Formation and Dissolution of Carbon Clusters in SiO2

Oxidation of SiC produces SiO2 while CO is released. A `reoxidation' step at lower temperatures is, however, necessary to produce high-quality SiO2. This step is believed to cleanse the oxide of residual C without further oxidation of the SiC substrate. We report first-principles calculations that describe the nucleation and growth of O-deficient C clusters in SiO2 under oxidation conditions, fed by the production of CO at the advancing interface, and their gradual dissolution by the supply of O under reoxidation conditions. We predict that both CO and CO2 are released during both steps.Comment: RevTex, 4 pages, 2 ps figures, to appear in Phys. Rev. Lett. (June 25, 2001