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Robust Control for an Active Suspension System via Continuous Sliding-Mode Controllers
Get PDFIn this paper, a simple control methodology is proposed to stabilize the position of the sprung mass of the quarter car system. The simplicity of the structure of the proposal facilitates the application in real systems. Such methodology allows five different continuous sliding-mode controllers to be selected by means of two similar designs to mitigate the chattering effect. These robust controllers ensure the exponential stability of the sprung mass of a quarter car system in the presence of some class of non-vanishing disturbances. The closed-loop stability is guaranteed by means of a Lyapunov function approach and Input-to-State Stability properties. Some simulations and comparisons show the effectiveness of the proposed control schemes compared to a classic linear approach. Additionally, some experimental results show the effectiveness of the proposed controllers in the Quanser Active Suspension System
Transfer pricing: changing views in changing times
Get PDFTransfer pricing for tax purposes has long been contentious, but recent political and public concerns about tax avoidance have energised critiques of current rules and debates about proposals for change. Transfer pricing tax rules are underpinned by the arm’s length principle and we consider how the common understanding of this principle has developed and changed, as criticism of it has grown and there have been increasing calls for change. In this qualitative study we draw on Bourdieusian concepts: we focus on the views of senior transfer pricing professionals relating to the UK and the US and consider how their views and transfer pricing practices have changed over a period of field disruption. This is important because calls for transformation of the field need to be cognizant of the extent to which existing practices are firmly embedded and thereby resilient to change. We find that over the period of our longitudinal study the senior transfer pricing professionals show a degree of adaptability to the use of the arm’s length principle, which continues to dominate
Sea level rise will change estuarine tidal energy: A review
Get PDFClimate change induced sea level rise (SLR) is likely to impact estuarine hydrodynamics and associated processes, including tidal energy. In this study, a hierarchy of factors influencing the future of estuarine tidal energy resources is proposed based on their relevance to SLR. These include primary factors (e.g., tidal prism, tidal range, tidal current, tidal asymmetry), secondary factors (e.g., sediment transport), and tertiary factors (e.g., shifts in estuarine shape/landform). The existing uncertainty regarding SLR impacts on tidal energy resource is high, given the spatial variability of estuaries. SLR may cause tidal ranges or currents to strengthen or weaken, depending on estuarine shape and boundary conditions (e.g., presence or absence of levees and adjacent low-lying areas). To date, local site studies have not resulted in an overarching assessment of SLR effects on tidal energy resources and comparative studies encompassing different regions and estuary types are recommended in order to address the existing knowledge gaps and provide insights for policymakers and stakeholders. SLR implications to estuarine tidal energy resources may be particularly important as SLR-induced changes can alter the available resource within a renewable energy development's operational lifetime (∼20–30 years for tidal stream devices and ∼120 years for tidal barrages). In this regard, broader environmental impacts, as well as techno-economic assessments, are difficult to predict and long-term management decisions associated with harnessing the potential of tidal energy schemes within estuaries should be made with caution
Tidal dynamics in palaeo-seas in response to changes in physiography, tidal forcing and bed shear stress
Get PDFSimulating hydrodynamic conditions in palaeo-ocean basins is needed to better understand the effects of tidal forcing on the sedimentary record. When combined with sedimentary analyses, hydrodynamic modelling can help inform complex temporal and spatial variability in the sediment distribution of tide-dominated palaeo-ocean basins. Herein, palaeotidal modelling of the epicontinental Upper Jurassic (160 Ma, lower Oxfordian) Sundance and Curtis seas of North America reveals possible regional-scale variations in tidal dynamics in response to changes in ocean tidal forcing, physiographic configuration and bottom drag coefficient. A numerical model forced with an M2 tidal constituent at the open boundary shows that the magnitude and location of tidal amplification, and the variability in current velocity and bed shear stress in the basin, were controlled by palaeophysiography. Numerical results obtained using a depth of 600 m at the ocean boundary of the system enable the prediction of major facies trends observed in the lower Curtis Formation. The simulation results also highlight that certain palaeophysiographic configurations can either permit or prevent tidal resonance, leading to an overall amplification or dampening of tides across the basin. Furthermore, some palaeophysiographic configurations generated additional tidal harmonics in specific parts of the basins. Consequently, similar sedimentary successions can emerge from a variety of relative sea-level scenarios, and a variety of sedimentary successions may be deposited in different parts of the basin in any given relative sea-level scenario. These results suggest that the interpretation of sedimentary successions deposited in strongly tide-influenced basins should consider changes in tidal dynamics in response to changing sea level and basin physiography
Shades of Rage: Applying the Process Model of Emotion Regulation to Managing Anger After Brain Injury
Get PDFUncontrollable anger is common following an acquired brain injury (ABI), with impaired emotion regulation (ER) being one of the main contributors. Existing psychological interventions appear moderately effective, though studies typically include limitations such as small sample sizes, issues of long-term efficacy, and standardization of content.While ER has been a popular research field, the study of ER for anger management after ABI is less well investigated, and contains few interventions based on the widely used Process Model of ER. This review surveys the efficacy of ER strategies in individuals with ABI, and proposes a novel research design for future interventions. Recommendations are made about: strategy number and type, shared decision-making, approaches to data analysis, and mode of deliver
Coulomb excitation of the mirror pair
Get PDFBackground: Electric-quadrupole (E2) strengths relate to the underlying quadrupole deformation of a nucleus and present a challenge for many nuclear theories. Mirror nuclei in the vicinity of the line of N=Z represent a convenient laboratory for testing deficiencies in such models, making use of the isospin symmetry of the systems.Purpose: Uncertainties associated with literature E2 strengths in 23Mg are some of the largest in Tz=∣∣12∣∣ nuclei in the sd shell. The purpose of the present paper is to improve the precision with which these values are known, to enable better comparison with theoretical models.Methods: Coulomb-excitation measurements of 23Mg and 23Na were performed at the TRIUMF-ISAC facility using the TIGRESS spectrometer. They were used to determine the E2 matrix elements of mixed E2/M1 transitions.Results: Reduced E2 transition strengths, B(E2), were extracted for 23Mg and 23Na. Their precision was improved by factors of approximately 6 for both isotopes, while agreeing within uncertainties with previous measurements.Conclusions: A comparison was made with both shell-model and ab initio valence-space in-medium similarity renormalization group calculations. Valence-space in-medium similarity renormalization group calculations were found to underpredict the absolute E2 strength, in agreement with previous studies
Rhesus monkeys have an interoceptive sense of their beating hearts
Get PDFThe sensation of internal bodily signals, such as when your stomach is contracting or your heart is beating, plays a critical role in broad biological and psychological functions ranging from homeostasis to emotional experience and self-awareness. The evolutionary origins of this capacity and, thus, the extent to which it is present in nonhuman animals remain unclear. Here, we show that rhesus monkeys (Macaca mulatta) spend significantly more time viewing stimuli presented asynchronously, as compared to synchronously, with their heartbeats. This is consistent with evidence previously shown in human infants using a nearly identical experimental paradigm, suggesting that rhesus monkeys have a human-like capacity to integrate interoceptive signals from the heart with exteroceptive audiovisual information. As no prior work has demonstrated behavioral evidence of innate cardiac interoceptive ability in nonhuman animals, these results have important implications for our understanding of the evolution of this ability and for establishing rhesus monkeys as an animal model for human interoceptive function and dysfunction. We anticipate that this work may also provide an important model for future psychiatric research, as disordered interoceptive processing is implicated in a wide variety of psychiatric conditions
Overlap not Gap: Understanding the Relationship between Animal Communication and Language with Prototype Theory
Get PDFWhat is the relationship between language and animal communication? This has largely been discussed within research on language evolution and disciplines beyond linguistics, but impacts upon the study of language generally. There are two extant views on the nature of this relationship: either there is a stark divide, with language considered as completely unique to humans, or there is a linear continuum from animal communication to language, aligning with gradualist evolutionary principles. Yet, each view involves considerable limitations. Moreover, there is no agreed-upon definition of language, which further complicates the determination of its relationship with animal communication. Withdrawing from attempts to define language with traditional fixed criteria (as characteristic of classical categorisation), this article suggests a different approach to conceptualising language and assessing the concept’s applicability to other species. Categorising phenomena through family resemblances and graded typicality of features (as in prototype-based categorisation) enables a new approach to conceptualising language, its typological diversity amongst humans, and the systematic integration of animal communication. Ultimately, with an illustrative model, this article proposes a strong overlap of animal communication with language. This approach illuminates more of the nature of language, facilitates more cohesive interdisciplinary research, and introduces potentially positive ethical implications for non-humans
Impact of molybdenum cross sections on FHR analysis
Get PDFA recent benchmarking effort, under the auspices of the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA), has been made to evaluate the current state of modeling and simulation tools available to model fluoride salt-cooled high temperature reactors (FHRs). The FHR benchmarking effort considered in this work consists of several cases evaluating the neutronic parameters of a 2D prismatic FHR fuel assembly model using the participants’ choice of simulation tools. Benchmark participants blindly submitted results for comparison with overall good agreement, except for some which significantly differed on cases utilizing a molybdenum-bearing control rod. Participants utilizing more recently updated explicit isotopic cross sections had consistent results, whereas those using elemental molybdenum cross sections observed reactivity differences on the order of thousands of pcm relative to their peers. Through a series of supporting tests, the authors attribute the differences as being nuclear data driven from using older legacy elemental molybdenum cross sections. Quantitative analysis is conducted on the control rod to identify spectral, reaction rate, and cross section phenomena responsible for the observed differences. Results confirm the observed differences are attributable to the use of elemental cross sections which overestimate the reaction rates in strong resonance channels