Robust Control Synthesis for Gust Load Alleviation from Large Aeroelastic Models with Relaxation of Spatial Discretisation

This paper introduces a methodology for the design of gust load control systems directly from large aeroelastic models with relaxation of spatial discretisation. A convenient state-space representation of the vortex-panel unsteady aerodynamics suitable for control synthesis is presented. This allows a full understanding of the dynamics of the linearized vortex aeroelastic model and is suitable for control system design. Through the use of robust controllers, large reductions in loading could be achieved. Comparisons are also made between robust and classical control methods. It further demonstrates that controllers synthesized from models of coarse spatial discretizations and of an order of magnitude smaller in size were capable of rejecting disturbances on fully converged models, with performances comparable to expensive higher order controllers developed from full models

Tensions between public environmental regulation and private property interests: the case of land clearing in New South Wales

On 29 July 2014, Ian Turnbull, the patriarch of a farming family from northern New South Wales, allegedly shot and killed Glen Turner, an officer of the NSW Office of Environment and Heritage. Turnbull had been investigated and fined previously by the department for illegal land clearing. According to media reports, Turnbull's family claimed that he had become a "broken man", himself a victim of the government's "aggressive stance", and had "battled" legal proceedings regarding illegal vegetation clearing on his property.1 Turner's tragic death, and Turnbull's state of mind, have been unashamedly politicised by federal, state and local government figures who have sought to conflate the alleged murder with the debate over vegetation laws. Certainly, vegetation laws have been the subject of political controversy in several Australian states for well over a decade. Although different states have different laws, and changes of state governments sometimes involve changes to vegetation laws, ultimately vegetation laws have become a fixture on the Australian legal landscape. Trying to draw a causal connection between vegetation laws and the alleged murder of a government officer is not only insensitive and inflammatory, it is also indicative of a deep misunderstanding of Australian laws and their interaction

Origin, evolution and dynamic context of a Neoglacial lateral-frontal moraine at Austre Lovénbreen, Svalbard

Moraines marking the Neoglacial limits in Svalbard are commonly ice cored. Investigating the nature of this relict ice is important because it can aid our understanding of former glacier dynamics. This paper examines the composition of the lateral–frontal moraine associated with the Neoglacial limit at Austre Lovénbreen and assesses the likely geomorphological evolution. The moraine was investigated using ground-penetrating radar (GPR), with context being provided by structural mapping of the glacier based on an oblique aerial image from 1936 and vertical aerial imagery from 2003. Multiple up-glacier dipping reflectors and syncline structures are found in the GPR surveys. The reflectors are most clearly defined in lateral positions, where the moraine is substantially composed of ice. The frontal area of the moraine is dominantly composed of debris. The core of the lateral part of the moraine is likely to consist of stacked sequences of basal ice that have been deformed by strong longitudinal compression. The long term preservation potential of the ice-dominated lateral moraine is negligible, whereas the preservation of the debris-dominated frontal moraine is high. A glacier surface bulge, identified on the 1936 aerial imagery, provides evidence that Austre Lovénbreen has previously displayed surge activity, although it is highly unlikely to do so in the near future in its current state. This research shows the value of relict buried ice that is preserved in landforms to aiding our understanding of former glacier characteristics

Evolution of high-Arctic glacial landforms during deglaciation

Glacial landsystems in the high-Arctic have been reported to undergo geomorphological transformation during deglaciation. This research evaluates moraine evolution over a decadal timescale at Midtre Lovénbreen, Svalbard. This work is of interest because glacial landforms developed in Svalbard have been used as an analogue for landforms developed during Pleistocene mid-latitude glaciation. Ground penetrating radar was used to investigate the subsurface characteristics of moraines. To determine surface change, a LiDAR topographic data set (obtained 2003) and a UAV-derived (obtained 2014) digital surface model processed using structure-from-motion (SfM) are also compared. Evaluation of these data sets together enables subsurface character and landform response to climatic amelioration to be linked. Ground penetrating radar evidence shows that the moraine substrate at Midtre Lovénbreen includes ice-rich (radar velocities of 0.17 m ns−1) and debris-rich (radar velocities of 0.1–0.13 m ns−1) zones. The ice-rich zones are demonstrated to exhibit relatively high rates of surface change (mean thresholded rate of −4.39 m over the 11-year observation period). However, the debris-rich zones show a relatively low rate of surface change (mean thresholded rate of −0.98 m over the 11-year observation period), and the morphology of the debris-rich landforms appear stable over the observation period. A complex response of proglacial landforms to climatic warming is shown to occur within and between glacier forelands as indicated by spatially variable surface lowering rates. Landform response is controlled by the ice-debris balance of the moraine substrate, along with the topographic context (such as the influence of meltwater). Site-specific characteristics such as surface debris thickness and glaciofluvial drainage are, therefore, argued to be a highly important control on surface evolution in ice-cored terrain, resulting in a diverse response of high-Arctic glacial landsystems to climatic amelioration. These results highlight that care is needed when assessing the long-term preservation potential of contemporary landforms at high-Arctic glaciers. A better understanding of ice-cored terrain facilitates the development of appropriate age and climatic interpretations that can be obtained from palaeo ice-marginal landsystems

Aeroservoelastic modelling and active control of very large wind turbine blades for gust load alleviation.

The increased flexibility of wind turbine blades necessitates not only accurate predictions of the aeroelastic effects, but also requires active control techniques to overcome potentially damaging loadings and oscillations. An aeroservoelastic model, capturing the structural response and the unsteady aerodynamics of very large rotors, will be used to demonstrate the potential of closed-loop load alleviation using aerodynamic control surfaces. The structural model is a geometrically-nonlinear composite beam, which is linearised around equilibrium rotating conditions and coupled with a linearised 3D Unsteady Vortex Lattice Method (UVLM) with prescribed helicoidal wake. This provides a direct higher fidelity solution to BEM for the dynamics of deforming rotors in attached flow conditions. The resulting aeroelastic model is in a state-space formulation suitable for control synthesis. Flaps are modeled directly in the UVLM formulation and LQG controllers are finally designed to reduce fatigue by about 26% in the presence of continuous turbulence. Trade-offs between reducing root-bending moments (RBM) and suppressing the negative impacts on torsion due to flap deployment will also be investigated

Owning the Earth

The Earth and jurisprudence are both systems. The Earth is a system of physical and interlinked relationships. Jurisprudence is a system of abstract laws. Jurisprudence is a human creation. As such, jurisprudence is a system that depends for its existence on the systems of Earth because the former is the creation of a species whose existence is of the latter. It is therefore important, indeed necessary, to situate the system of laws within the physical context of the Earth's systems, because although the law currently situates itself above or separate to the physical realm, in reality the converse is true. Humans are physical beings dependent on, and subject to, their only home and ultimate jurisdiction - Earth. In a discussion of the idea of Earth Jurisprudence it is necessary to consider the laws of land and water ownership and use in terms of their physical (or economic) viability. In other words, laws that regulate the ownership and use of the Earth and its resources --- - -, - - --- - - - --- -_. -would-need-to-both-facilitate-and-regulate-human-earth ·relations-th-ar-are-consistent-with the unilateral dependence of humans and their socio-economic systems on the Earth's systems

The level and duration of RSV-specific maternal IgG in infants in Kilifi Kenya

Background Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants. The rate of decay of RSV-specific maternal antibodies (RSV-matAb), the factors affecting cord blood levels, and the relationship between these levels and protection from infection are poorly defined. Methods A birth cohort (n = 635) in rural Kenya, was studied intensively to monitor infections and describe age-related serological characteristics. RSV specific IgG antibody (Ab) in serum was measured by the enzyme linked immunosorbent assay (ELISA) in cord blood, consecutive samples taken 3 monthly, and in paired acute and convalescent samples. A linear regression model was used to calculate the rate of RSV-matAb decline. The effect of risk factors on cord blood titres was investigated. Results The half-life of matAb in the Kenyan cohort was calculated to be 79 days (95% confidence limits (CL): 76–81 days). Ninety seven percent of infants were born with RSV-matAb. Infants who subsequently experienced an infection in early life had significantly lower cord titres of anti-RSV Ab in comparison to infants who did not have any incident infection in the first 6 months (P = 0.011). RSV infections were shown to have no effect on the rate of decay of RSV-matAb. Conclusion Maternal-specific RSV Ab decline rapidly following birth. However, we provide evidence of protection against severe disease by RSV-matAb during the first 6–7 months. This suggests that boosting maternal-specific Ab by RSV vaccination may be a useful strategy to consider