Optimal Design and Operational Monitoring of Wind Turbine Blades

The wind turbine blade is a critical component of any wind energy system. Its design, testing, and performance monitoring play a key role in power generation. With the increased use of composites and longer blades, a need to review existing monitoring sensors and use emergent novel ones is urgent among industry practitioners. In addition, an overview relating blade testing to Campbell diagrams and non-contact sensors have not been addressed as part of blade optimization. Based on design loads under IEC 61400-23 standards, the chapter explores various contact and non-contact sensors for design validation as well as their exploratory use in a three-tier structural health monitoring (SHM) framework for blade’s operational performance monitoring. The chapter also includes a case study in the non-contact use of ground-based radar (GBR) in the optimal design of blades and real-time in-field monitoring using condition parameters. Lastly, the chapter addresses the lack of practical guidelines in the complementary use of GBR within a 3-tier SHM framework. Such use has the intent of building a cohesive understanding of GBR use for blade optimization and operational monitoring

Novel non-contact deformation health monitoring of towers and rotating composite based wind turbine blades using interferometric ground-based radar

This paper describes the use of non-contact quasi monostatic ground-based radar (GBR) for system health monitoring (SHM) of the blades of wind turbines. It focusses on the deflection monitoring of these blades and validates the results from the design parameters extracted from numerical simulations during the design stage. Using a 3-tier SHM framework, acquisition of deflection in the time-domain is done by the GBR. These results are then transformed into the frequency-domain using a fast Fourier transform (FFT) to obtain the resonant frequencies as second step in the 3-step SHM framework. The third step of validation / hypothesis testing of the measured results with initial simulated design parameter is then effected to demonstrate that the GBR can be used for deformation health monitoring of composite blades and towers. The work demonstrates that the GBR can be deployed as a non-contact, real-time monitor that can measure deflections and natural-vibration frequencies of wind turbines blades. This enables smart monitoring of dynamic structures in urban and non-urban settings

A Child's Concept of Pain: An International Survey of Pediatric Pain Experts.

A child's 'concept of pain' refers to how they understand what pain actually is, what function pain serves, and what biological processes are thought to underpin it. We aimed to determine pediatric pain experts' opinions of: (1) the importance and usefulness of assessing a child's concept of pain in clinical and/or research settings; (2) the usefulness of the content of items within currently published adult-targeted resources for assessing a child's concept of pain; and (3) important domains of a child's concept of pain to assess. Forty-nine pediatric pain experts (response rate = 75.4%) completed an online survey. Descriptive statistics and frequency of responses were analyzed. Experts from all included disciplines reported that assessing a child's concept of pain is important and useful both clinically and in a research setting (>80% reported very or extremely useful for each item). Experts considered that the content of 13 items from currently published adult-targeted resources was useful, but the wording was too complex for children aged 8-12 years. Experts considered that all seven of the proposed domains of a child's concept of pain was important to assess. The findings can be used to inform the development of an assessment tool for a child's concept of pain

Deflection characterisation of rotary systems using a ground-based radar

In the last two decades, an increase in large rotary machines/systems has been witnessed. To ensure safe operation of these systems especially due to extreme stress caused by centrifugal forces as well as the wind or water loadings, regular structural health monitoring (SHM) of the unbalanced parameters, particularly at the blade tips is necessary. For this, the use of non-contact sensors provides the most appropriate approach; however, millimetric out-of-plane deflection monitoring using non-contact sensors at distances >1 m has not been comprehensively addressed for rotary systems, like wind turbines. This study presents a modelling environment to simulate radar returns to analyse rotary systems. Employing Sammon mapping as a dimensionality reduction procedure in conjunction with 2D visualisation, the study demonstrates the characterisation of dynamic deflection parameters using a fast, portable ground-based interferometric radar (GBR). Comparisons between the GBR results with those of a Leica AR20 GPS indicate a divergence ±12.79 mm. The study utilises SHM framework to acquire, normalise, extract, and validate GBR signals within an SHM framework for structures under test or for deflection validation of the new system. Further, it contributes to the non-contact structural fatigue damage detection during design, testing, and operating stages of rotary structures blade tips

Testing WHAM-FTOX with laboratory toxicity data for mixtures of metals (Cu, Zn, Cd, Ag, Pb)

The WHAM-FTOX model describes cation toxicity to aquatic organisms in terms of (a) accumulation by the organism of metabolically-active protons and metals at reversible binding sites, and (b) differing toxic potencies of the bound cations. Cation accumulation (νi in mol g-1) is estimated through calculations with the WHAM chemical speciation model by assuming that organism binding sites can be represented by those of humic acid. Toxicity coefficients (αi) are combined with νi to obtain the variable FTOX ( = ∑ αiνi) which, between lower and upper thresholds (FTOX,LT, FTOX,UT), is linearly related to toxic effect. Values of αi, FTOX,LT and FTOX,LT are obtained by fitting toxicity data. Reasonable fits (72% of variance in toxic effect explained overall) were obtained for four large metal mixture acute toxicity experiments involving daphnids (Cu, Zn, Cd), lettuce (Cu, Zn, Ag) and trout (Zn, Cd, Pb). Strong non-additive effects, most apparent in results for tests involving Cd, could be explained approximately by purely chemical competition for metal accumulation. Tentative interpretation of parameter values obtained from these and other experimental data suggests the following order of bound cation toxicity: H < Al < (Cu Zn Pb UO2) < (Cd Ag). Another trend is a strong increase in Cd toxicity relative to that of Zn, as organism complexity increases (from bacteria to fish)

Cosmology from Cosmic Microwave Background and Galaxy Clusters

We present the results of analysis of constraints on cosmological parameters from cosmic microwave background (CMB) alone and in combination with galaxy cluster baryon fraction assuming inflation--generated adiabatic scalar fluctuations. The CMB constraints are obtained using our likelihood approximation method (Bartlett et al., 2000, Douspis et al., 2001). In the present analysis we use the new data coming from MAXIMA and BOOMERanG balloon borne experiments, the first results of the DASI interferometer together with the COBE/DMR data. The quality of these independent data sets implies that the $C_\ell$ are rather well known, and allow reliable constraints. We found that the constraints in the $\Omega-H_0$ plane are very tightened, favouring a flat Universe, that the index of the primordial fluctuations is very close to one, that the primordial baryon density is now in good agreement with primordial nucleosynthesis. Nevertheless degeneracies between several parameters still exist, and for instance the constraint on the cosmological constant or the Hubble constant are very weak, preferred values being low. A way to break these degeneracies is to ``cross-constrain'' the parameters by combining with constraints from other independent data. We use the baryon fraction determination from X-ray clusters of galaxies as an additional constraint and show that the combined analysis leads to strong constraints on all cosmological parameters. Using a high baryon fraction ($\sim 15$ for $h = 0.5$) we found a rather low Hubble constant, values around 80 km/s/Mpc being ruled out. Using a recent and low baryon fraction estimation ($\sim 10$ for $h = 0.5$) we found a preferred model with a low Hubble constant and a high density content ($\Omega_m$), an Einstein--de Sitter model being only weakly ruled out

Complex patterns of local adaptation in teosinte

Populations of widely distributed species often encounter and adapt to specific environmental conditions. However, comprehensive characterization of the genetic basis of adaptation is demanding, requiring genome-wide genotype data, multiple sampled populations, and a good understanding of population structure. We have used environmental and high-density genotype data to describe the genetic basis of local adaptation in 21 populations of teosinte, the wild ancestor of maize. We found that altitude, dispersal events and admixture among subspecies formed a complex hierarchical genetic structure within teosinte. Patterns of linkage disequilibrium revealed four mega-base scale inversions that segregated among populations and had altitudinal clines. Based on patterns of differentiation and correlation with environmental variation, inversions and nongenic regions play an important role in local adaptation of teosinte. Further, we note that strongly differentiated individual populations can bias the identification of adaptive loci. The role of inversions in local adaptation has been predicted by theory and requires attention as genome-wide data become available for additional plant species. These results also suggest a potentially important role for noncoding variation, especially in large plant genomes in which the gene space represents a fraction of the entire genome

Tidal dwarf galaxies in the nearby Universe

We present a statistical observational study of the tidal dwarf (TD) population in the nearby Universe, by exploiting a large, homogeneous catalogue of galaxy mergers compiled from the SDSS. 95% of TD-producing mergers involve two spiral progenitors, while most remaining systems have at least one spiral progenitor. The fraction of TD-producing mergers where both parents are early-type galaxies is <2%, suggesting that TDs are unlikely to form in such mergers. The bulk of TD-producing systems inhabit a field environment and have mass ratios greater than 1:7 (the median value is 1:2.5). TDs forming at the tidal-tail tips are ~4 times more massive than those forming at the base of the tails. TDs have stellar masses that are less than 10% of the stellar masses of their parents and typically lie within 15 optical half-light radii of their parent galaxies. The TD population is typically bluer than the parents, with a median offset of ~0.3 mag in the (g-r) colour and the TD colours are not affected by the presence of AGN activity in their parents. An analysis of their star formation histories indicates that TDs contain both newly formed stars (with a median age of ~30 Myr) and old stars drawn from the parent disks, each component probably contributing roughly equally to their stellar mass. Thus, TDs are not formed purely through gas condensation in tidal tails but host a significant component of old stars from the parent disks. Finally, an analysis of the TD contribution to the local dwarf-to-massive galaxy ratio indicates that ~6% of dwarfs in nearby clusters may have a tidal origin, if TD production rates in nearby mergers are representative of those in the high-redshift Universe. Even if TD production rates at high redshift were several factors higher, it seems unlikely that the entire dwarf galaxy population today is a result of merger activity over the lifetime of the Universe.Comment: MNRAS in pres

Ending the reign of short-acting β2-agonists in Australia?

Acknowledgements We would like to acknowledge and thank Steph James, Kiran Dhillon, Sophie Jones, Rob Campbell, Ying Liu, Marion Magee, Ondrej Rejda, Lisa Sugg, and Nicole O'Sullivan for their valuable contributions.Peer reviewe

Best practice coral restoration for the Great Barrier Reef

As the Great Barrier Reef (GBR) continues to degrade through repeated mass bleaching events, crown-of-thorns starfish and major disease outbreaks, and the impacts of intense cyclones, pressure is growing for direct intervention to assist the recovery of reef-building corals. Decreasing coral cover on the GBR and other Australian reefs has been recognised as a serious problem relatively recently in Australia but follows a global trend, with many overseas reefs now highly degraded. Various types of coral restoration, rehabilitation and assisted recovery projects have been trialled overseas for decades and it makes sense to look at what has and hasn’t worked overseas to determine a range of options that may suit GBR conditions. Some direct interventions to assist coral recovery have been trialled in Australia such as transplanting corals, algae removal to promote coral recovery and larval enhancement promoting direct coral recruitment. In addition, after physical damage from cyclones, ship strikes or dragged anchors, local dive operators and dive clubs (permitted or unpermitted) often attempt to assist the recovery of corals by tipping over flipped tabular corals and reattaching broken branching corals or sea fans. These latter assisted recovery techniques are rarely underpinned by scientific data on coral recovery. A lack of best practice guidelines for these actions limits the chance of success and increases the health and safety risks of these activities