Investigation of grapevine areas under climatic stress using high resolution atmospheric modelling: case studies in South Africa and New Zealand

High-resolution atmospheric simulations (500 m) were used to assess viticultural areas under climatic stress in South Africa and New Zealand. The potential areas in which high daytime temperature stress was likely to affect grapevine photosynthesis and grape composition were identified. Results indicated different diurnal temperature variations within the two areas due to synoptic and local environmental factors, often associated with the influence of terrain

Planetary bearing defect detection in a commercial helicopter main gearbox with vibration and acoustic emission

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Helicopter gearboxes significantly differ from other transmission types and exhibit unique behaviors that reduce the effectiveness of traditional fault diagnostics methods. In addition, due to lack of redundancy, helicopter transmission failure can lead to catastrophic accidents. Bearing faults in helicopter gearboxes are difficult to discriminate due to the low signal to noise ratio (SNR) in the presence of gear vibration. In addition, the vibration response from the planet gear bearings must be transmitted via a time-varying path through the ring gear to externally mounted accelerometers, which cause yet further bearing vibration signal suppression. This research programme has resulted in the successful proof of concept of a broadband wireless transmission sensor that incorporates power scavenging whilst operating within a helicopter gearbox. In addition, this paper investigates the application of signal separation techniques in detection of bearing faults within the epicyclic module of a large helicopter (CS-29) main gearbox using vibration and Acoustic Emissions (AE). It compares their effectiveness for various operating conditions. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were combined for this investigation. In addition, this research discusses the feasibility of using AE for helicopter gearbox monitoring

Essai sur l'art de restaurer les estampes et les livres; ou, Traité sur les meilleurs procédés pour blanchir, détacher, décolorier, réparer et conserver les estampes livres et dessins.

Mode of access: Internet

Numerical modelling of lithosphere-asthenosphere interaction in a subduction zone

International audienceWe developed a new 2-D numerical approach to study solid-fluid coupling applied to subduction zones. The lithosphere is characterised by an elastic or elastoplastic behaviour and the asthenosphere by a homogeneous isoviscous fluid. The temperature effects are ignored and viscosity and density are constant in time. The solid and the fluid problem are discretised by the finite elements method (FEM). The same solid code used in Hassani et al. [Hassani, R., Jongmans, D., Chery, J., Study of plate deformation and stress in subduction processes using two-dimensional numerical models, J. Geophys. Res. (1997) 102 17951-17965.] has been used to compute the solution of the solid problem. The Stokes problem is solved by a direct solver with a stabilisation procedure. We used a very simple staggered coupling method where the fluid domain is regularly re-meshing. We observed numerical instabilities when the time step is not sufficiently small, especially when strong coupling between the solid and the fluid occurs. We have tested different configurations where the lithosphere is elastic or elastoplastic and show how the slab geometry, the topography and the stress regime in the plates are affected by the viscous resistance of the mantle. We observed that the asthenosphere viscosity is a fundamental parameter in the subduction process. For subduction with an extensional regime in the upper plate, we observe a linear decrease of the extensional stress as a function of the asthenospheric viscosity

Experience with low-cost telemedicine in three different settings. Recommendations based on a proposed framework for network performance evaluation

BACKGROUND: Telemedicine has been used for many years to support doctors in the developing world. Several networks provide services in different settings and in different ways. However, to draw conclusions about which telemedicine networks are successful requires a method of evaluating them. No general consensus or validated framework exists for this purpose. OBJECTIVE: To define a basic method of performance measurement that can be used to improve and compare teleconsultation networks; to employ the proposed framework in an evaluation of three existing networks; to make recommendations about the future implementation and follow-up of such networks. METHODS: Analysis based on the experience of three telemedicine networks (in operation for 7-10 years) that provide services to doctors in low-resource settings and which employ the same basic design. FINDINGS: Although there are many possible indicators and metrics that might be relevant, five measures for each of the three user groups appear to be sufficient for the proposed framework. In addition, from the societal perspective, information about clinical- and cost-effectiveness is also required. The proposed performance measurement framework was applied to three mature telemedicine networks. Despite their differences in terms of activity, size and objectives, their performance in certain respects is very similar. For example, the time to first reply from an expert is about 24 hours for each network. Although all three networks had systems in place to collect data from the user perspective, none of them collected information about the coordinator's time required or about ease of system usage. They had only limited information about quality and cost. CONCLUSION: Measuring the performance of a telemedicine network is essential in understanding whether the network is working as intended and what effect it is having. Based on long-term field experience, the suggested framework is a practical tool that will permit organisations to assess the performance of their own networks and to improve them by comparison with others. All telemedicine systems should provide information about setup and running costs because cost-effectiveness is crucial for sustainability

Climate change and the future of South Africa's wine industry, in AAWE Working Paper No. 105

AgriwetenskappeLandbou-EkonomiePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Cyclostationary modelling of rotating machine vibration signals

International audienc

Essai sur l'art de restaurer les estampes et les livres,

English translation of the 2d rev. ed., 1858, with prefatory and supplementary matter omitted.Autograph reproduction of typewritten copy.Mode of access: Internet