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Elective Amputation and Neuroprosthetic Limbs
No full textThis paper explores the impact that developments in the field of neuroprosthetics will have on the ethical viability of healthy limb amputation, specifically in cases of Body Integrity Identity Disorder (BIID). Developments in the field have meant that the prospect of such artificial components matching the utility of their biological counterparts is now a possibility. As such, arguments against the provision of therapeutic, healthy limb amputation which are grounded in the perceived resultant harm of disability need to be reconsidered. Drawing on philosophical insights, as well as the field of disability studies and BIID research, this paper argues that such neuroprosthetics presents a challenge for the fundamental dichotomy between the disabled and ‘abled’, including the latter’s perceived superiority. It goes on to suggest that healthy limb amputation, for those with BIID, should not be dismissed simply because of the distastefulness of the procedure, but rather be evaluated based upon its own merits
The role of solvation in proton transfer reactions: implications for predicting salt/co-crystal formation using the ΔpKa rule
No full textThe ΔpKa rule is commonly applied by chemists and crystal engineers as a guideline for the rational design of molecular salts and co-crystals. For multi-component crystals containing acid and base constituents, empirical evidence has shown that ΔpKa > 4 almost always leads to salts, ΔpKa < –1 almost always leads to co-crystals and ΔpKa between –1 and 4 can be either. This paper reviews the theoretical background of the ΔpKa rule and highlights the crucial role of solvation in determining the outcome of the potential proton transfer from acid to base. New data on the frequency of occurrence of co-crystals and salts in multi-component crystal structures containing acid and base constituents show that the relationship between ΔpKa and the frequency of salt/co-crystal formation is influenced by the composition of the crystal. For unsolvated co-crystals/salts, containing only the principal acid and base components, the point of 50% probability for salt/co-crystal formation occurs at ΔpKa ≈ 1.4, while for hydrates of co-crystals and salts, this point is shifted to ΔpKa ≈ –0.5. For acid-base crystals with the possibility for two proton transfers, the overall frequency of occurrence of any salt (monovalent or divalent) versus a co-crystal is comparable to that of the whole data set, but the point of 50% probability for observing a monovalent salt vs a divalent salt lies at ΔpKa,II ≈ –4.5. Hence, where two proton transfers are possible, the balance is between co-crystals and divalent salts, with monovalent salts being far less common. Finally, the overall role played by the “crystal” solvation is illustrated by the fact that acid-base complexes in the intermediate region of ΔpKa tip towards salt formation if ancillary hydrogen bonds can exist. Thus, the solvation strength of the lattice plays a key role in the stabilisation of the ions
Formation-containment tracking and scaling for multiple quadcopters with an application to choke-point navigation
No full textThis paper investigates the cooperative control problem of choke-point navigation for multiple quadcopters when only their subgroup is equipped with obstacle detecting sensors. We define a quadcopter as a leader if it is equipped with an obstacle detecting sensor; otherwise, it is a follower. In addition, we introduce a virtual leader agent to create the group motion. First, we apply the leader-follower approach and propose a formation-containment tracking controller for multiple quadcopters to track the time-varying velocity of the virtual leader agent. At the same time, the leader quadcopters form the prescribed formation while the follower quadcopters converge inside a safe region, which is the convex hull spanned by those leaders. Then, we introduce a scaling vector into the displacement-based formation constraints. When the leader quadcopters identify the choke-point via their obstacle detecting sensors, they update the scaling variable to adjust the size of the formation (i.e. the safe region) and guide all quadcopters to safely pass through the choke-point. The proposed cooperative controllers are distributed because each quadcopter’s control command only relies on the information states from its neighbours. Finally, two autonomous flight experiments, including formation-containment tracking and choke-point navigation, are provided to validate the effectiveness of the proposed cooperative control laws
Evolution of the Xenon (e,2e) Differential Cross Section from a Coplanar Geometry to the Perpendicular Plane in the Intermediate Energy Regime
No full textNew (e,2e) differential cross section measurements from xenon are presented as the scattering geometry changes from coplanar to the perpendicular plane. Measurements were taken at energies of 60 eV, 80 eV, and 100 eV above the ionization potential. These new data are compared to measurements collected for the first four noble gases and to that from xenon at lower energies. A new technique is used to measure the ratio of relative cross-sections between xenon and helium using a xenon-helium mixture. With this data absolute differential cross sections of xenon can be determined once the helium cross sections have been calculated
Evaluating and Updating a Design Space for Augmented Reality Television
No full textAs Augmented Reality Television (ARTV) transitions out of the feasibility phase, it is crucial to understand the impact of designdecisions on the viewers’ ARTV experiences. In a previous study, six ARTV design dimensions were identified by relying on insightsfrom existing prototypes. However, the set of possible dimensions is likely to be broader. Building on top of previous work, wecreate an ARTV design space and present it in a textual cheat sheet. We subsequently evaluate the cheat sheet in a between-subjectstudy (𝑛 = 10), with participants with wide-ranging expertise. We identified six new dimensions (genre, broadcast mode, audiencedemographics, cartoonish vs. photoreal representation, modality, and privacy), and a new aspect (360◦) for the display dimension. Inlight of our observations, we provide an updated ARTV design space and observe that asking participants to write ARTV scenarioscan be an effective method for harvesting novel design dimensions
THE DEVELOPMENT OF A NEW METHOD TO COMPARE THE FATIGUE CRACK GROWTH RATES OF AUSTENITIC STAINLESS STEEL OPERATING IN A PWR PRIMARY COOLANT SUBJECTED TO PLANT REALISTIC TEMPERATURE LOADING
No full textFatigue Crack Growth Rates (FCGRs) of austenitic stainless steels can be significantly enhanced when tested in a high temperature water environment compared to those tested in air. Existing FCGR models are based on simple isothermal waveform loading. Recent work has highlighted that there may be a potential benefit into taking account of plant realistic loading waveforms in fatigue assessments as these may be less damaging than predict ions based on simple loading conditions. As a result, new methods to account for these plant realistic loads have been developed to reduce excess conservatism of existing methods for predicting FCGRs.To provide confidence in these methods, a previous UK thermomechanical fatigue testing program me has been conducted on Compact Tension (C(T)) specimens subjected to plant realistic loads, with the crack length and Crack Growth Rates CGRs being monitored in situ using the Direct Current Potential Drop (DCPD) technique. This paper utilizes three different methodologies to evaluate the CGR of samples that underwent corrosion fatigue in different conditions namely; DCPD, post mortem measurement of crack advance using Scanning Electron Microscopy (SEM) and the measurement of the spacing between striations to infer CGR.It was found that DCPD provided a good global average of FCGRs at the crack front but does not capture local changes associated with the local microstructureOverall, it was shown that post mortem examination for stage measurements can be reliably applied to infer CGR on samples that were not instrumented with DCP
Some Effects of Surface Finish and LWR Environment on Environmentally-assisted Crack Initiation in Alloy 182
No full textWithin the European Commission funded project MEACTOS, environmentally-assisted crack (EAC) initiation of Alloy 182 was addressed by performing constant extension rate tensile (CERT) and constant load (CL) testing of flat, tapered tensile specimens in both boiling water reactor (BWR) normal water chemistry (NWC) and pressurized water reactor (PWR) primary water environment. Four surface finishes were investigated, namely: ground which serves as reference (RS), industrial face-milled (STI), advanced-machined (SAM) and two shot peened conditions (SP, initial and later). After testing the critical stress for initiating a crack was derived by locating the critical section (the border between areas showing and not showing surface cracking after testing) and calculating the associated local stress. In a first analysis of the CERT results, the critical stress was plotted against the nominal strain rate (cross-head displacement rate divided by the length of the tapered gauge section) and an exponential curve was fitted to it; yielding a characteristic critical stress (extrapolation to zero nominal strain rate) and a characteristic nominal strain rate (rendering the nominal strain rate dimensionless under the exponent). In a second analysis of the CERT results, an initiation model, which is strain rate and stress level dependent, was fitted to obtain a usage towards EAC initiation of 1 in the experimentally-determined critical cross section. CL testing was performed under the same and accelerated test conditions, achieved by increasing temperature and changing test environment. The overall conclusion is that (1) EAC initiation performance is better in the BWR/NWC than in the PWR environment, (2) effects of surface finish are more clearly visible in the PWR environment, (3) EAC initiation performance is better for SAM than for RS or STI which are similar and in turn better than the original SP. A “higher quality” SP surface showed an improvement in EAC initiation performance and this correlated well with the lower surface hardness measured for the latter meaning that hardness could be used as a measure for the quality of surface treatments in respect of EAC initiation
A five-spin supramolecule for simulating quantum decoherence of Bell states
No full textWe report a supramolecule that contains five spins of two different types, and with, crucially, two different and predictable interaction energies between the spins. The supramolecule is characterised and the interaction energies demonstrated by EPR spectroscopy. Based on the measured parameters we propose experiments that would allow this designed supramolecule to be used to simulate quantum decoherence in maximally entangled Bell states that could be used in quantum teleportation
Legitimacy, Power, and Aesthetics, in the International Baccalaureate
No full textThis paper explores the facilitation of the emancipatory in an International Baccalaureate (IB) context of privilege. It aligns with the idea that capitalism, even in welfare state democracies or ‘do good’ corporations, maintains the interests of the owners of capital. It is by nature unjust and exploitative and must conceal this injustice by securing a (spurious) legitimacy for itself (Edgar, 2006, p. 88). This makes a rare methodological contribution as the article provides critical ‘meta-analysis’ (Card, 2015) of IB research literature by prioritising work that affords insight into the lived reality within the IB-Sphere. It then triangulates this analysis through the work of German Social Philosopher Jürgen Habermas (1970; 1981; 1983; 1989; 1991).This work provides a significant and timely contribution to ‘franchised education’ (Apple, 2000; Ball, 2012) in the 21st Century, and will be of essential reading to scholars, policy makers and leadership whether involved in the IB, or active in the Neo Liberal spaces of education more generally: such as Multi Trust Academies, Free Schools, or Charter Schools. This is thanks to the lessons learned over nearly 60 years of educational franchise in a diverse and globalising sphere as presented here from IB research through critical analysis. <br/
Construction of a destabilizing nonlinearity for discrete-time uncertain Lurye systems
No full textThis paper considers the instability of a Lurye system consisting of an uncertain, discrete-time, linear time-invariant plant in feedback with a slope-restricted nonlinearity. There is a large literature on analyzing the stability of such systems. This includes various conditions for proving stability of the Lurye system, including the Circle criterion and the use of O’Shea-Zames-Falb multipliers. In many cases, these conditions are sufficient but not necessary to prove stability. In contrast, there is also some work to construct specific nonlinearities that demonstrate the instability of the Lurye system (with the nominal plant dynamics). This paper considers a more general case where the plant has dynamic uncertainty. The goal is to construct both an instance of the uncertain model and a corresponding nonlinearity that combined make the Lurye system unstable. A limit cycle oscillation is also computed to verify the instability. A simple example is provided to demonstrate the results