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The establishment of a Digital Twin of an operating engineered system can increase the potency of Structural Health Monitoring (SHM) tools, which are then bestowed with enhanced predictive capabilities. This is particularly relevant for wind energy infrastructures, where the definition of remaining useful life is a main driver for assessing the efficacy of these systems. In order to ensure a proper representation of the physical structure, the monitored response of the Digital Twin should match the one experienced by the actual system throughout the complete spectrum of its operational conditions. In most typical SHM configurations, it is only possible to rely on output-only measurements, acquired from finite positions within a structure, which naturally raises the challenge of recovering the full-field operational response, including unmeasured locations. This problem, also known as Virtual Sensing (VS), has been treated using different schemes, including Bayesian filtering and Modal Expansion (ME). In this paper, the Augmented Kalman Filter (AKF) is exploited to this end; a tool which allows for simultaneous full-field response and unmeasured input prediction. The common issue of Bayesian filtering relies on calibration of the filters defining parameters, namely the assumed measurement and process noise covariance levels. While the first is directly related to the accuracy of the employed physical sensors, the latter often acts as a tuning parameter for improving the reliability of the prediction. The process noise covariance adjustment is often performed in an offline fashion, either by making use of regularization methods, e.g., the L-curve method, or via trial and error. In this work, we propose a methodology for automated process noise covariance adaptation, relying on response estimates recovered by means of an improved ME approach. The method is validated on experimental data from a large scale research Wind Turbine (WT) blade made of glass fiber reinforced plastics., Mechanical Systems and Signal Processing, 184, ISSN:0888-3270, ISSN:1096-1216

Reliable and efficient damage detection is critical for the use of lightweight materials in the mechanical and aerospace industries. Within the context of Non-Destructive Testing (NDT), vibration-based tests have been applied for many decades to inspect components without damaging or debilitating their use. For posterior fault recognition, Artificial Intelligence techniques have achieved high success for a number of structural applications. In this work Testing, Simulation and Artificial Intelligence have been combined in order to develop a defect detection procedure. The use of an Optomet Scanning Laser Doppler Vibrometer (SLDV) for such tests provides an interesting solution to measure the vibration velocities on the structure surface. The algorithm for identifying the defects is based on the Local Defect Resonance (LDR) concept, which looks to the high frequency vibrations to get a localized resonant activation of the defect. Artificial Intelligence (AI) techniques were implemented with the aim of creating an automatic procedure based on features extraction for damage detection. Wavelet transformation and modal analysis were used to provide inputs to the AI techniques. In order to better understand the limitation in terms of defect detection, damaged plates were modelled and simulated in order to perform a sensitivity analysis. Finally, an overall comparative overview of different algorithms results was also obtained.

Current crisis, causing structural long-term changes in the economy and society, is offering a challenge to the insurance sector, whose primary role lies in the protection of individuals and productive activities. The insurance industry can take this opportunity towards achieving the objective of social well-being with the design of new insurance products and incentives. In this work we propose a particular type of securitization scheme where the health risk in a broad sense is transferred to capital market. For example, this tool can be exploited by firms to cover the risks of damage to the health of workers and office workers. Certain discount policies by insurance companies may encourage activities aimed at improving the health system and the work safety. An appropriate morbidity index is used to price this type of policy. Numerical results are offered and discussed.

In the paper we present a securitized bond set in the macrocosm of sustainable fi-nance. The product is generated by a securitization scheme that involves three actors: firms, issuing insurance contracts to protect the health of workers; insurers; investors, betting on the good health management of workers. The product is a derivative linked to an underlying representing the trend of the pandemic, specifically the present COVID-19 number of infected persons compared to its expected value. Aim of the paper is to frame the product in specific categories recognized within the ESG criteria. In particular, two specific categories are identified within the Principles Responsible Investments, which integrate the bond within the ESG products. Moreover, from an insurance point of view, the product can be considered within the most innovative asset categorization for impact finance, recent for the insurance sector. This area en-compasses a limited number of recently developed tools aimed to sustainability and impact.

Over the past few years, the application fields for digital image correlation (DIC) have significantly broadened and are now extensively used not only for material characterization and deformation analysis but also for vibration and dynamic testing. The key advantage over more traditional technologies such as accelerometer- or laser-based measurement is the fact that all points of interest can be measured at once or over a limited number of repetitions without mass loading the structure or having to deal with complex cabling scenarios. While qualitative analysis, such as operational deflection shapes, proved to be very successful and straightforward, performing classical modal analysis on frequency response functions between a load cell signal and the deformations obtained by applying digital image correlation still requires extra care when setting up the experiments. In this paper, the effect of different cameras, camera settings, excitation levels, and speckle pattern on the modal parameters of a simple plate structure will be investigated and compared with classical acceleration measurement. The results will also be compared with numerical simulations where the accuracy of the mode shapes can be easily and quantitatively assessed.

The demographic, economic and social changes that have characterized the last decades, and the dramatic financial crisis that has taken place since 2008, have led to a demand for structural changes in the pension sector and a growing interest in individual pension products. Hence the need, for most elderly people, to liquidate their fixed assets, which are usually the homes in which they live. This highlights products such as reverse mortgages and domestic reversibility plans. Within this context, we propose a contractual scheme where an immediate life annuity is obtained by paying a single-premium in the form of real estate rights (RERs), for example by transferring to an insurer the property title of a house or a similar realty, while keeping its usufruct or a restricted bundle of rights. The level of the installments depends on the fair value of the transferred RER at the contract’s issue, the life expectancy of the insured and the expected growth rate of the real estate market value. The contract design is developed by considering the control of the financial risk inherent in the contract itself, because of the prospective changes in the value of the RERs, and the level of the insurer’s leverage. Finally, we provide some numerical evidence of the proposed contractual structure, in order to compare the level of the installments according to the house return forecasts in different European countries.

Changes in demographic structure of a country and economic condition are interconnected causes of new needs that motivate the launch of new financial instruments. One of these is the Reverse Mortgage (RM): a contract in which a homeowner borrows a part or the totality of the future liquidation value of his/her home at the time of his/her death. The paper analyses the contractual details and discusses the impact of the main variables on the lamp sum that an elderly homeowner receives at the inception of the contract. The risks factors that influence the pricing of the RM are both strictly demographic, i.e. the life of the contractor, and financial, in particular the evolution of the real estate market and of the financial market.

Dumping syndrome is a common but underdiagnosed complication of gastric and oesophageal surgery. We initiated a Delphi consensus process with international multidisciplinary experts. We defined the scope, proposed statements and searched electronic databases to survey the literature. Eighteen experts participated in the literature summary and voting process evaluating 62 statements. We evaluated the quality of evidence using grading of recommendations assessment, development and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 33 of 62 statements, including the definition and symptom profile of dumping syndrome and its effect on quality of life. The panel agreed on the pathophysiological relevance of rapid passage of nutrients to the small bowel, on the role of decreased gastric volume capacity and release of glucagon-like peptide 1. Symptom recognition is crucial, and the modified oral glucose tolerance test, but not gastric emptying testing, is useful for diagnosis. An increase in haematocrit >3% or in pulse rate >10 bpm 30 min after the start of the glucose intake are diagnostic of early dumping syndrome, and a nadir hypoglycaemia level

Reverse mortages (RM) provide an attractive way to increase retirement incomes and to face the needs of health care for elderly people. The RM market is exposed to a number of risks: (1) longevity risk, as retirees’ life expectancy increases, (2) interest rate risk, especially in the low-rate post- crisis period, (3) property market risk, in the last stage of the current business cycle. We measure the overall risk for an insurer with a book of RM contracts. We also evaluate the optimal demand for RM in a retiree’s investment portfolio, taking into account diversification with respect to other asset classes..Numerical results are shown and suggestions to further developments of the market are offered.

The recent pandemic and the recommendations of the WHO regarding the systematic nature that will characterize the spread of the future pandemic in the world require a deep rethinking of economic-social logics. ESG (Environmental Social Governance) strategies will play a key role in all sectors to ensure sustainable development together with the reduction of social inequalities. In this context, the insurance sector cannot fail to be a proactive and resilient player.

L’Articolo descrive il ruolo culturale dei matematici durante il “ventennio” e la “fascistizzazione” della matematica, così come è stata definita dagli storici, che avvenne attraverso un controllo minuzioso dei libri di testo e delle attività di ricerca di studiosi e intellettuali, soffermandosi poi su quelle scelte autarchiche del regime che colpirono gravemente la comunità matematica.

‘Matematica e Capitale umano’ è oggi più che mai un binomio inscindibile. E lo è a buon ragione in quanto, con i mercati dei capitali globali, gli avanzamenti nella tecnologia hanno determinato cambiamenti nella domanda di lavoro e nelle qualifiche professionali (skills) richieste. Ora tra i fattori di crescita di un paese, un ruolo rilevante assume l’accumulazione di capitale umano e questo fattore può essere accumulato in due modi: tramite l’istruzione e tramite il progresso tecnologico.

In recent years, high-speed cameras permit to record high-resolution images at several thousand frames-per-second. In addition to this, Digital Image Correlation (DIC) measures full-field displacements and strains in 3D from stereo camera images and perform Operational Deflection Shape and Modal Analysis on the data. Several papers have demonstrated the validity of the approach on laboratory cases, comparing and validating the results with those obtained using more standard measurement techniques (accelerometers, strain gauges, lasers). Very limited cases have been however investigated on the possibility to combine high-speed DIC and standard accelerometer-based measurement to fully exploit the advantages of both techniques. In this paper, the possibility to combine global acceleration measurements on an F16 during a classical Ground Vibration Test with local full-field camera measurement is investigated. The advantages of the combined approach are clear, as the standard measurement will provide the global mode shapes of the aircraft, which can be used for certification and modal validation, while the local high-speed camera measurement system can provide displacement and strain field data with an unmatchable spatial resolution. In particular, the paper will focus on the possibility of using the local displacement measurements to better characterize the non-linear behavior of the connection between the wing and the payload.

Recent observations suggest that the mean mesoscale oceanic zonal velocity field is dominated by alternating jet-like features often referred to as striations. Here the generating dynamics of Northeast Pacific striations are explored with a set of 120 year eddy-permitting model simulations. Simulations are conducted with decreasing complexity toward idealized configurations retaining the essential dynamics and forcing necessary for striation development. For each simulation, we diagnose the spin-up of the ocean model and the sensitivity of striation generation to topography, coastal geometry, and wind stress, which modulates the gyre circulation and the nonlinearity of the flow field. Results indicate that Northeast Pacific striations develop predominantly at the eastern boundary and migrate westward in congruence with beta-plumes in both the nonlinear and quasi-linear regimes. Mean striations are governed by coastline geometry, which provides quasi-steady vorticity sources energized by eastern boundary current instabilities.

Oceanic observations collected during the VOCALS-REx cruise time period, 1–30 November 2008, are assimilated into a regional ocean model (ROMS) using 4DVAR and then analyzed for their dynamics. Nonlinearities in the system prevent a complete 30-day fit, so two 15-day fits for 1–15 November and 16–30 November are executed using the available observations of hydrographic temperature and salinity, along with satellite fields of SST and sea-level height anomaly. The fits converge and reduce the cost function significantly, and the results indicated that ROMS is able to successfully reproduce both large-scale and smaller-scale features of the flows observed during the VOCALS-REx cruise. Particular attention is focused on an intensively studied eddy at 76° W, 19° S. The ROMS fits capture this eddy as an isolated rotating 3-D vortex with a strong subsurface signature in velocity, temperature and anomalously low salinity. The eddy has an average temperature anomaly of approximately −0.5 °C over a depth range from 50–600 m and features a cold anomaly of approximately −1 °C near 150 m depth. The eddy moves northwestward and elongates during the second 15-day fit. It exhibits a strong signature in the Okubo-Weiss parameter, which indicates significant nonlinearity in its evolution. The heat balance for the period of the cruise from the ocean state estimate reveals that the horizontal advection and the vertical mixing processes are the dominant terms that balance the temperature tendency of the upper layer of the ocean locally in time and space. Areal averages around the eddies, for a 15-day period during the cruise, suggest that vertical mixing processes generally balance the surface heating. Although, this indicates only a small role for lateral advective processes in this region during this period, this quasi-instantaneous heat budget analysis cannot be extended to interpret the seasonal or long-term upper ocean heat budget in this region.

Aim The use of microsurgical technique and loupes magnification as a support to traditional surgery can help surgical performance and prevent complications in thyroid surgery. Patients and methods Between January 2004 and December 2014, 782 patients with thyroid diseases were operated by our team with microsurgical technique and loupes magnification 4.5x. All patients had pre and postoperative vocal cords assessment and calcemia and the collected data were analysed. Results Among the 782 patients, only six patients (0.77%) had unilateral vocal fold immobility treated with medical therapy, phoniatric and neck physiotherapy. All six patients showed complete laryngeal recovery of motility 6/8 weeks after treatment. There were not cases of permanent monolateral or bilateral vocal cord palsy. In 84 patients there were signs and symptoms of hypocalcemia. In 81 patients (10.36%) the restoring of biochemical parameters and the resolution of symptoms occurred between 2 and 6 weeks and in 3 cases (0.38%) there was permanent hypocalcemia more than six months. Conclusion The use of microsurgical technique and loupes magnification in thyroid surgery are safety and effective procedures, that require an appropriate training in reconstructive microsurgery, but may significantly reduce post-operative complications. Here, we report for the first time the largest series of thyroid surgery performed with the use of microsurgical technique and loupes magnification, analysing the postoperative morbidity. In view of our results, we suggest the routine use of 4.5X loupes and microsurgical technique in thyroid surgery.

This research aimed at understanding the dynamics controlling decadal variability in the Pacific Ocean and its interactions with global-scale climate change. The first goal was to assess how the dynamics and statistics of the El Nino Southern Oscillation and the modes of Pacific decadal variability are represented in global climate models used in the IPCC. The second goal was to quantify how decadal dynamics are projected to change under continued greenhouse forcing, and determine their significance in the context of paleo-proxy reconstruction of long-term climate.

Context: The interest and popularity of Pilates is increasing worldwide. In addition to being used in fitness programs, it is being used in some rehabilitation programs. Evidence Acquisition: This review summarizes level III evidence from 1995 to 2009 obtained from PubMed (MEDLINE), CINAHL, and the Internet. Meta-analyses, systematic reviews, randomized controlled trials, and controlled trials published in peer-reviewed journals were retrieved for appraisal. The keywords searched were Pilates and core stabilization. Results: Ninety articles were identified in MEDLINE and CINAHL; 9 articles satisfied the inclusion criteria for level III evidence. Conclusion: There is a scientific basis for the effectiveness of Pilates exercise, with limited evidence to support it as a rehabilitative intervention.

In the Northern California Current (NCC), zooplankton communities show interannual and multiyear shifts in species dominance that are tracked by survival of salmon populations. These zooplankton community changes correlate with the Pacific Decadal Oscillation (PDO) index: a 'warm-water' copepod species group is more abundant during warm (positive) phases of the PDO and less abundant during cold (negative) phases; the reverse occurs for a 'cold-water' species group. The observed relationship led to the hypothesis that the relative dominance of warm/cold-water copepods in the NCC is driven by changes in the horizontal advection of surface water over different phases of the PDO. To test this hypothesis, variation in surface water advection to coastal regions of the NCC over the period of 1950-2008 was investigated using a Regional Ocean Modeling System (ROMS) and passive tracer experiments, then was compared with zooplankton collected off Oregon since 1996. Results showed that surface water advection varied with the phase of the PDO; the low-frequency component of advection anomalies strongly correlated with copepod species composition (R > 0.9). During positive phases of the PDO, current anomalies were northward and onshore, resulting in transport of warmer waters and the associated copepods into the region. During negatives phases, increased equatorward current anomalies led to a copepod community that was dominated by cold-water taxa. Our results support the hypothesis that climate-driven changes in basin-scale circulation controls copepod community composition in the NCC, and demonstrate that large-scale climate forcings downscale to influence local and regional ecosystem structure.

Digital Image Correlation (DIC) is a non-contact full-field image analysis technique which allows to retrieve strains and displacements in three dimensions at the surface of any type of material and under arbitrary loading. In recent years, high-speed and high-resolution cameras have been developed for static as well as for dynamic applications. As consequence, the application fields for DIC have broadened and it has proven to be a flexible and very accurate measurement solution for deformation analysis and material characterization. Nevertheless, nowadays DIC is often used in a qualitative manner rather than as a metrological tool. This is especially due to the time-consuming task related to the post-processing of the images. When compared to other vibration testing techniques, full-field approaches (such as DIC) allow a greater flexibility by providing a very dense number of experimental data over a single measurement. Another advantage is related to the fact that the geometry is automatically extracted from the images. In this paper, the possibility to combine global acceleration measurements on a small component with local full-field standard machine vision quasi-static camera measurements is investigated. In particular, the regularization properties of DIC and their impact on modal analysis will be studied in detail. Strains and displacements could be used in a second stage for modal analysis purpose in order to characterize the dynamic behaviour of the specimen in a certain frequency range. Different approaches could be used for combining together the data obtained during the tests. The most obvious approach would be the alignment of the time histories based on reference signals for Frequency Response Functions (FRFs) calculation prior to perform any further processing. Unfortunately this is not always possible because of synchronization issues. An alternative possibility, in case broadband random excitation is used, requires to process time data into auto and crosspowers and identify the modal parameters by using Operational Modal Analysis (OMA).

Modern wind turbine blades are being tested for certification purposes in accordance to the IEC-64100 standard. Part 23 of the norm details the requirements for the full scale structural testing of rotor blades. As a minimum, it requires measurement of the first and second flap wise and first edge wise natural frequencies. It lists damping and mode shapes as other blade properties which may be of interest and optionally measured. The paper presents the modal model parameters estimation based on the experimental modal analysis. In two tests performed, the input force has been introduced through impact hammer and two electrodynamic shakers excitation. Several first modes had been identified for both excitation methods, including first torsional mode of the investigated blade. Results of the modal tests can be used to (a) provide more detailed information about the structural dynamics characteristics of the blade and (b) improve the design by adjusting the dynamic properties of the blade to some desired condition.

Decadal fluctuations of the ocean and atmosphere over the North Pacific Ocean significantly affect the weather and climate of North America and Eurasia. They also cause transitions between different states of marine ecosystems across the Pacific Ocean 1‐3 . An important fraction of North Pacific low-frequency variability is linked to the North Pacific Gyre Oscillation 4 , a climate pattern associated with decadal fluctuations of the ocean circulation. Decadal variations in the North Pacific Gyre Oscillation are characterized by a pattern of sea surface temperature anomalies that resemble the central Pacific El Nino, a dominant mode of interannual variability with far-reaching effects on global climate patterns 5‐7 . Here we use an ensemble of simulations with a coupled ocean‐ atmosphere model to show that the sea surface temperature anomalies associated with central Pacific El Nino force changes in the extra-tropical atmospheric circulation. These changes in turn drive the decadal fluctuations of the North Pacific Gyre Oscillation. Given that central Pacific El Nino events could become more frequent with increasing levels of greenhouse gases in the atmosphere 8 , we infer that the North Pacific

We present the feasibility of a prototype, near real-time assimilation and ensemble prediction system for the Intra-Americas Sea run autonomously aboard a ship of opportunity based on the Regional Ocean Modeling System (ROMS). Predicting an ocean state depends upon numerical models that contain uncertainties in their modeled physics, initial conditions, and model state. An advanced model, four-dimensional variational assimilation, and ensemble forecasting techniques are used to account for each of these uncertainties. Every 3 days, data from the previous 7 days period were assimilated to generate an estimate of the circulation and to create an ensemble of 2 weeks forecasts of the ocean state. This paper presents the methods and results for a multi-resolution assimilation system and ensemble forecasts of surface fields and dominant surface circulation features. When compared to post-processed science quality observations, the state estimates suffer from our reliance on real-time, quick-look satellite observations of the ocean surface. Despite a number of issues, the ensemble forecast estimate is often superior to observational persistence. This proof-of-concept prototype performed well enough to reveal deficiencies, provide useful insights, valuable lessons, and guidance for future improvements in real-time ocean forecasting.

The Inverse Ocean Modeling (IOM) System is a modular system for constructing and running weak-constraint four-dimensional variational data assimilation (W4DVAR) for any linear or nonlinear functionally smooth dynamical model and observing array. The IOM has been applied to four ocean models with widely varying characteristics. The Primitive Equations Z-coordinate-Harmonic Analysis of Tides (PEZ-HAT) and the Regional Ocean Modeling System (ROMS) are three-dimensional, primitive equations models while the Advanced Circulation model in 2D (ADCIRC-2D) and Spectral Element Ocean Model in 2D (SEOM-2D) are shallow-water models belonging to the general finite-element family. These models, in conjunction with the IOM, have been used to investigate a wide variety of scientific phenomena including tidal, mesoscale, and wind-driven circulation. In all cases, the assimilation of data using the IOM provides a better estimate of the ocean state than the model alone.

Systematic improvements in algorithmic design of regional ocean circulation models have led to significant enhancement in simulation ability across a wide range of space/time scales and marine system types. As an example, we briefly review the Regional Ocean Modeling System, a member of a general class of three-dimensional, free-surface, terrain-following numerical models. Noteworthy characteristics of the ROMS computational kernel include: consistent temporal averaging of the barotropic mode to guarantee both exact conservation and constancy preservation properties for tracers; redefined barotropic pressure-gradient terms to account for local variations in the density field; vertical interpolation performed using conservative parabolic splines; and higher-order, quasi-monotone advection algorithms. Examples of quantitative skill assessment are shown for a tidally driven estuary, an ice-covered high-latitude sea, a wind- and buoyancy-forced continental shelf, and a mid-latitude ocean basin. The combination of moderate-order spatial approximations, enhanced conservation properties, and quasi-monotone advection produces both more robust and accurate, and less diffusive, solutions than those produced in earlier terrain-following ocean models. Together with advanced methods of data assimilation and novel observing system technologies, these capabilities constitute the necessary ingredients for multi-purpose regional ocean prediction systems.

We present the background, development, and preparation of a state-of-the-art 4D variational (4DVAR) data assimilation system in the Regional Ocean Modeling System (ROMS) with an application in the Intra-Americas Sea (IAS). This initial application with a coarse model shows the efficacy of the 4DVAR methodology for use within complex ocean environments, and serves as preparation for deploying an operational, real-time assimilation system onboard the Royal Caribbean Cruise Lines ship Explorer of the Seas. Assimilating satellite sea surface height and temperature observations with in situ data from the ship in 14 day cycles over 2 years from January 2005 through March 2007, reduces the observation-model misfit by over 75%. Using measures of the Loop Current dynamics, we show that the assimilated solution is consistent with observed statistics.

The South Pacific region represents the world’s largest oceanic water mass and plays a significant role in the earth’s climate systems. This region also contains the largest group of island nations, most of whom are dependent on marine resources for their livelihoods. Several of the largest coastal and oceanic fisheries also occur in this region (FAO, 2014). In addition, for the countries associated with the southern Pacific Ocean region, the sea provides significant social, cultural and economic benefits, with many countries being heavily reliant on both coastal and oceanic marine resources (Bell et al., 2013). Increasing coastal populations and climate change are expected to augment human demands on already fully exploited or over-exploited marine resources, threatening both food security and sustainable livelihoods (Bell et al., 2011). Therefore, it is imperative that the science that describes and predicts linked biophysical and human systems is understood and developed to meet these needs. Climate change will have many impacts on marine ecosystems, with implications for end users including individuals, local communities, industries and governments. Improved scientific support for policy and management decision-making in the face of these potential impacts is essential.

A numerical model forced with average annual cycles of climatological winds, surface heat flux, and temperature and salinity along the open boundaries is used to demonstrate that Haida Eddies are typically generated each winter off Cape St. James, at the southern tip of the Queen Charlotte Islands of western Canada. Annual cycles of sea-surface elevation measured at coastal tide gauges and TOPEX/POSEIDON crossover locations are reproduced with reasonable accuracy. Model sensitivity studies show that Haida Eddies are baroclinic in nature and are generated by the merging of several smaller eddies that have been formed to the west of Cape St. James. The generation mechanism does not require the existence of instability processes and is associated with the mean advection of warmer and fresher water masses around the cape from Hecate Strait and from the southeast. These advected water masses generate plumes of buoyant flow, which intensify and sustain small patches of anticyclonic circulation immediately to the northwest of the cape. When the flow is stronger, several of these smaller eddies can merge to generate a larger eddy, the Haida Eddy. Similar to observations, a typical generation-shedding cycle for larger Haida Eddies in the model is 3–4 months. Consistent with previous in situ water property measurements, these experiments show that the eddies are generally comprised of mixed-layer water from Hecate Strait, Queen Charlotte Sound, and the continental shelves off northern Vancouver Island. Their vertical extent during the mature stage is roughly 1000 m.

The gearbox is one of the key subsystems in a typical wind turbine. It has the task to transfer power from the low speed shaft connected to the rotor to the high speed shaft connected to the generator. Larger wind turbines require more power and gearboxes with higher load capacity need to be designed and a deep knowledge into gearbox dynamics becomes of fundamental importance. When dealing with a machine in operating conditions with several rotating components, components are introduced in the signal that make the application of standard techniques such as Operational Modal Analysis very difficult and in some cases almost impossible. For this reason, new techniques to tackle with these conditions were investigated in the past, such as Order Based Modal Analysis. This method represents an extension of standard OMA to extract a modal model from measurement on a machine during run-up (or run-down) conditions. The applicability limits of standard OMA are here demonstrated on the data acquired on a 13.2 MW wind turbine gearbox testing facility during controlled run-up conditions. The advantages of the proposed methodology will be demonstrated by firstly applying it on data simulated using a validated model of the testing facility. The additional challenges that need to be faced when applying the method to real data will also be presented.

Rotating machineries generally operate under very dynamic and complex conditions, during which structural nonlinearities, tonalities or other dynamic related phenomena may arise, affecting the assumptions made in the design phase. Techniques that allow accurately and confidently identifying the dynamic response are then of paramount importance in such complex scenarios. Wind turbine gearboxes are a typical example of such machines, as they operate under strong transient conditions caused by the turbulent and non-stationary wind speed as well as fluctuations in the electrical grid. If models can help predict these interactions, dedicated experiments need to be foreseen to characterize operational response and validate/improve the developed numerical models.

The growth of wind turbines in terms of power capacity and rotor diameter size has driven the research toward new studies and ideas. Nowadays high potential sites on land have already been taken and offshore locations need to be exploited taking advantage of the stronger wind. In 2009 a 5 MW concept has been proposed by NREL in order to be considered as the reference wind turbine for the next years. In 2013 a new reference model has been introduced by DTU Wind Energy, a 10 MW wind turbine. Both offshore wind turbines have been modeled by using an aeroelastic code and several simulations have been carried on with the main objective of developing advanced health monitoring techniques. As the first step to perform Structural health Monitoring (SHM) is the identification of the most sensitive parameters to structural degradation, advanced data analysis were developed. Methods such as the Multi-Blade Coordinate (MBC) transformation and the Harmonic Power Spectrum (HPS) have been validated and combined with Operational Modal Analysis to identify the modal parameters of the turbine in operational conditions, including sensors on the tower, blades and nacelle. Once the model and analysis techniques have been validated, damages have been introduced by adding lumped masses and by reducing the blades and/or the tower stiffness. Some SHM considerations have been drawn by analyzing the so-called whirling modes. They are due to the rotation of the blades and they can be observed only after that a pre-processing technique has been applied. They have been highlighted because they seem to be very sensitive to the introduction of small damages. doi: 10.12783/SHM2015/350

Pacific low-frequency variability (timescale > 8 years) exhibits a well-known El Niño-like pattern of basin-scale sea surface temperature, which is found in all the major modes of Pacific decadal climate. Using a set of climate model experiments and observations, we decompose the mechanisms contributing to the growth, peak, and decay of the Pacific low-frequency spatial variance. We find that the El Niño-like interdecadal pattern is established through the combined actions of Pacific meridional modes (MM) and the El Niño-Southern Oscillation (ENSO). Specifically, in the growth phase of the pattern, subtropical stochastic excitation of the MM energizes the tropical low-frequency variance acting as a red noise process. Once in the tropics, this low-frequency variance is amplified by ocean-atmospheric feedbacks as the pattern reaches its peak phase. At the same time, atmospheric teleconnections distribute the variance from the tropics to the extratropics, where the pattern ultimately decays. In this stochastic red noise model of Pacific climate, the timescale of the extra-tropical/tropical interactions (1-2 years) permits the stochastic excitation of the ENSO-like pattern of decadal and interdecadal variance.

The real-time structural damage detection on large slender structures has one of its main application on offshore Horizontal Axis Wind Turbines (HAWT). The renewable energy market is continuously pushing the wind turbine sizes and performances. This is the reason why nowadays offshore wind turbines concepts are going toward a 10 MW reference wind turbine model. The aim of the work is to perform operational analyses on the 10-MW reference wind turbine finite element model using an aeroelastic code in order to obtain long-time-low- cost simulations. The aeroelastic code allows simulating the damages in several ways: by reducing the edgewise/flapwise blades stiffness, by adding lumped masses or considering a progressive mass addiction (i.e. ice on the blades). The damage detection is then performed by means of Operational Modal Analysis (OMA) techniques. Virtual accelerometers are placed in order to simulate real measurements and to estimate the modal parameters. The feasibility of a robust damage detection on the model has been performed on the HAWT model in parked conditions. The situation is much more complicated in case of operating wind turbines because the time periodicity of the structure need to be taken into account. Several algorithms have been implemented and tested in the simulation environment. They are needed in order to carry on a damage detection simulation campaign and develop a feasible real-time damage detection method. In addition to these algorithms, harmonic removal tools are needed in order to dispose of the harmonics due to the rotation. ispartof: Journal of Physics - Conference Series vol:628 issue:1 ispartof: 11th International Conference on Damage Assessment of Structures (DAMAS 2015) location:Ghent, Belgium date:24 Aug - 26 Aug 2015 status: published

Even when thyroidectomy preserves vocal cord motility it may leave patients with changes in voice quality. Although superior laryngeal nerve (LSN) damage after thyroidectomy manifests with aspecific symptoms, laryngoscopy discloses only slight morphological changes that are difficult to assess. We want to investigate the voice function in asymptomatic patients one year after thyroidectomy and to compare the obtained data against those of a healthy control group.Thirty adult patients who had undergone thyroidectomy, all of them euphonic before and after the operation, were submitted to a complete voice assessment including voice self-evaluation tools, videolaryngostroboscopy and spectrographic analysis of voice. Primary outcome measures were differences between surgical patients and control group in terms of microperturbation of voice intensity and amplitude as measured by spectrographic analysis.In patients who had undergone thyroidectomy, acoustic parameters indicating amplitude microperturbations resulted slightly altered. All these values exceeded normal MDVP thresholds. Another interesting finding in our study sample concerns the lower F0 values we recorded in women patients after surgery than in healthy controls. Voice alterations may reflect prelaryngeal muscle scarring or fibrosis. Consider the possible alterations of vocal quality caused by scarring after surgery therefore strongly recommend surgery when the situation allows it, not to dissect the prelaryngeal muscles but only to spread apart.Our study conducted at least one year after thyroid surgery underlines that surgery-related slight voice deficits can persist over time. More refined phoniatric testing discloses voice alterations that normalize without specific rehabilitation therapy, therefore confirming that certain acoustic changes are clinically unimportant.

© The Society for Experimental Mechanics, Inc. 2014. The ability to identify the dynamic properties of offshore wind turbines allows validating and updating numerical tools, which can be used to enhance the design. At the same time, these dynamic parameters can serve as a basis to continuously monitor the integrity of the machine. However, modal identification of turbines in operating conditions still poses some major issues, in particular in removing the rotor harmonic components, which are polluting the measured signals. This paper will present and discuss some recent developments for removing harmonic components from operational wind turbine data. The possibility to track the evolution of specific modes is compared against classical techniques such as Time Synchronous Averaging and Cepstrum, which show limitations due to rotational speed fluctuations, amplitude modulation of the harmonic components and the interaction between the harmonics and the aerodynamic loads. The methodologies are firstly presented and then applied to real data of an offshore wind turbine installed in the Belgian North Sea. The ability to identify more accurately the modal parameters will allow improving the correlation with the varying environmental conditions and provide additional input data to validate numerical models. ispartof: pages:299-312 ispartof: Dynamics of Civil Structures vol:4 pages:299-312 ispartof: IMAC 2014 location:Orlando, FL, USA date:Feb - Feb 2014 status: published

OBJECTIVE: Latex allergy has become an increasing and clinically important problem. Several recommendation for secondary preventive measures have been advised. The aims of the study were to illustrate the results of the latex-safe protocol and to evaluate in allergic patients the role of risk factors for the development of latex allergy. METHODS: Latex-safe treatment was divided into the following phases: anamnestic identification, allergologic assessment, patient selection, intervention programme, preventive medication, operating room equipment, postoperative management, patient and family training, follow-up. RESULTS: Between 1998 and 2004, 6.832 patients underwent 7.333 operations. Anamnestic and diagnostic tests showed that 26 patients had latex allergy. 44 secondary perioperative latex-safe management have been accomplished in 26 children. No allergic event or complications linked to the procedure occurred. Atopy, congenital malformations frequently associated with latex allergy and the presence of 5 or more surgical procedures were the major risk factors recognized. Six out of the 26 patients (23%) had only one risk factor (atopy). Twenty out of 26 children (77%) had several associated risk factors: 8 of them had simultaneously 9 of the 10 analysed risk factors. Our data shows that, the higher their number, the higher the gravity of the allergy. CONCLUSIONS: Although latex allergy is a limited phenomenon, it is nevertheless quite frequent within risk groups. Most patients have simultaneously many risk factors for the development of such an allergy, and the occurrence of several risk factors increases severity of the allergy. Latex-safe perioperative management offers guarantees of safety against latex allergy phenomena

© The Society for Experimental Mechanics, Inc. 2014. The aim of this paper is to characterize the dynamic behavior of a wind turbine gearbox installed on a dynamic test rig to replicate operational conditions. Wind turbines and gearboxes operate under very dynamic and complex conditions, caused by turbulent wind, fluctuations in the electricity grid etc. In those conditions, structural nonlinearities in bearings and gears cause natural frequencies to be significantly influenced by the operational conditions. To verify the dynamic response of a multi-megawatt gearbox, a comprehensive test campaign has been performed in the context of the European project ALARM at the ZF Wind Power test rig. Accelerations have been measured at more than 250 locations on the test rig and for different load levels and operating conditions. This paper focuses on the influence of the torque levels on the identified modal parameters. The acquired time histories during run-ups have been processed using different Operational Modal Analysis techniques. The aim is to provide a modal model that can be used for correlation and updating of a flexible nonlinear multibody model of the whole test rig as well as vibration levels to estimate structure-borne noise in the different operating conditions. ispartof: pages:41-52 ispartof: Topics in Modal Analysis vol:7 pages:41-52 ispartof: IMAC 2014 location:Orlando, FL, USA date:Feb - Feb 2014 status: published

Antiplatelet therapy is the cornerstone of the pharmacologic management of patients with acute coronary syndrome (ACS). Over the last years, several studies have evaluated old and new oral or intravenous antiplatelet agents in ACS patients. In particular, research was focused on assessing superiority of two novel platelet adenosine diphosphate (ADP) P2Y12 receptor antagonists (i.e. prasugrel and ticagrelor) over clopidogrel. Several large randomized controlled trials have been undertaken in this setting and a wide variety of pre-specified and post hoc analyses are available that evaluated the potential benefits of novel antiplatelet therapies in different subsets of patients with ACS. The aim of this document is to review recent data on the use of current antiplatelet agents for in-hospital treatment of ACS patients. For each drug or class of drugs, strong evidence and/or areas of uncertainty that warrant further research are highlighted by examining 10 subgroups of patients with ACS.

[1] In the paper “North Pacific Gyre Oscillation modulates seasonal timing and ecosystem functioning in the California Current upwelling system, ” by F. Chenillat et al. (Geophysical Research Letters, 39, L01606, doi:10.1029/ 2011GL049966, 2012), Figure 4b is modified without change to the caption: black and white dots (averaged Chl-a CalCOFI data) were erroneous. The second sentence of paragraph 17 is changed in consequence to “General patterns of the twin simulations are in agreement with the main characteristics of the dynamics of the CCS (Figure 4b), albeit with a high Chl-a bias nearshore.”

An approach to the design of multistage microwave amplifiers in a prescribed frequency band with requirements about the transducer gain flatness and the maximum magnitude of the reflection coefficient at input and output is presented. The interstage equalizers are designed by imposing a suitable constraint on the maximum transducer gain, obtainable directly from the specifications; the input and output equalizer are obtained by imposing only the matching requirement. The method proposed allows a separate design of each network, which can be performed either through direct optimization or by means of a numerical synthesis. >

[1] Long-term timeseries of upper ocean salinity and nutrients collected in the Alaskan Gyre along Line P exhibit significant decadal variations that are shown to be in phase with variations recorded in the Southern California Current System by the California Cooperative Oceanic Fisheries Investigation (CalCOFI). We present evidence that these variations are linked to the North Pacific Gyre Oscillation (NPGO)—a climate mode of variability that tracks changes in strength of the central and eastern branches of the North Pacific gyres and of the Kuroshio-Oyashio Extension (KOE). The NPGO emerges as the leading mode of low-frequency variability for salinity and nutrients. We reconstruct the spatial expressions of the salinity and nutrient modes over the northeast Pacific using a regional ocean model hindcast from 1963-2004. These modes exhibit a large-scale coherent pattern that predicts the in-phase relationship between the Alaskan Gyre and California Current timeseries. The fact that large-amplitude, low-frequency fluctuations in salinity and nutrients are spatially phase-locked and correlated with a measurable climate index (the NPGO) open new avenues for exploring and predicting the effects of long-term climate change on marine ecosystem dynamics.