Former student and close colleague of the late Michael Scriven's for 26 years, Jane Davidson shares some insights into his personal side to shed light on where he was coming from as an evaluation ...theorist.
•Thermal energy storage options for nuclear power are compared in a parametric model.•Operating parameters are based on practical ranges for grid operation.•Discharge of the storage to a secondary ...cycle maximizes capacity and peaking power.•Sensible heat storage using rock is a promising low-cost storage material.
Thermal energy storage for nuclear power can increase the flexibility of low carbon baseload power plants and facilitate greater use of renewable energy sources. The thermodynamic performance and cost of approaches to integrate thermal energy storage with a 1050 MW nuclear power plant are compared in a parametric study over practical ranges of charge/discharge durations, peaking power and round-trip efficiency of the storage. Conceptual designs for sensible and latent heat storage modules are presented. The results quantify for the first time how different options for thermal energy storage affect technical performance of a nuclear power plant and are interpreted to identify the most efficient options and operating conditions. The three configurations are distinguished by charge and discharge operation. Configuration I charges the storage via high-pressure steam supply and discharges steam to the low-pressure turbine. Configuration II charges via high–pressure steam and discharges preheated condensate to the steam generator. Configuration IIII charges via low-pressure steam and discharges steam to a secondary Rankine cycle. The diurnal energy production ratio, or capacity factor, versus peaking power, and storage material cost are the metrics used to compare configurations. Configuration III, which does not require changes to the primary cycle turbines and thus has no detrimental impact on the efficiency of baseload operation, has the highest energy production ratio of 0.99. Energy production ratio increases as charging duration and discharge power are reduced. Configurations I and III can provide peaking power more than 1.5 times the baseload plant. Configuration II is limited to a peaking power of less than 1.1 times that of baseload and is cost effective in this range, albeit with lower energy production ratio than configuration III. Sensible heat storage in a rock bed is more economical than latent heat storage due to the relatively high cost of eutectic salt mixtures with appropriate melt temperatures. Keywords: thermal storage, nuclear, thermodynamic, sensible heat, latent heat
Wales is the first country in the world to have put into law the protection of future generations through its Well-being of Future Generations (Wales) Act 2015; the first country to have a legal ...mechanism through the Act to deliver on the Sustainable Development Goals and the first country to have put the Brundtland definition of sustainable development into law. What does this mean for the values taught in Welsh universities, and how can the university role be repurposed in the interests of future generations? Building on her research for the book
#futuregen: Lessons from a Small Country
which was published this year, Jane Davidson, who, in her previous role as Minister in Welsh Government, proposed what is now the Well-being of Future Generations (Wales) Act 2015, will explore the opportunities from this new values framework to transform the university sector, in particular, the student experience in Wales, and whether there are further lessons that would be valuable elsewhere.
A thermodynamic model of the ceria-based solar thermochemical redox cycle is presented with the objective of resolving the widely varying predictions of the solar-to-fuel efficiency possible with ...reduction carried out in a flow of inert sweep gas. The implications of the treatment of the gas–solid interaction are explored through comparison of mixed flow and countercurrent flow configurations of reactants. The mixed flow model is applied for the first time to both reduction and oxidation reactions. The mechanical work to produce sweep gas of varying purity, separate the products, and pump gases is included. The results identify the conditions necessary for efficient operation. The two models lead to substantially different predictions of the usage of sweep gas and oxidizer and process efficiency. Efficiencies predicted with the conservative mixed flow model reach a maximum of 11% for water splitting at 1073 K, assuming reduction at 1773 K, heat recovery of 80% of the sensible heat of the gases, and an optimistic 75% heat recovery of the sensible heat of the solid ceria. Without solid phase heat recovery, the maximum efficiency is 4%. With the countercurrent model, the predicted solar-to-fuel efficiency reaches 41% for water splitting at 1563 K without solid phase heat recovery. Though theoretically attractive, the countercurrent flow model predicts unattainable efficiencies due to the assumption of chemical equilibrium at both the inlet and outlet of the reduction and oxidation reactors and yields nonphysical results for oxidation temperatures less than 1563 K. Thus, we urge caution in drawing conclusions about the promise of metal oxide cycles on the basis of the countercurrent flow model. Nonetheless, it is reasonable to anticipate that the ceria cycle with inert-swept reduction and a temperature swing between reduction and oxidation may achieve commercially viable solar-to-fuel efficiencies, in between the predictions of the mixed and countercurrent models, through the careful design of reactors to provide gas and solid phase heat recovery and favorable gas–solid flow configurations.
The research literature concerning gesture in musical performance increasingly reports that musically communicative and meaningful performances contain highly expressive bodily movements. These ...movements are involved in the generation of the musically expressive performance, but enquiry into the development of expressive bodily movement has been limited. In two studies this paper explores the expressive components of bodily movement in both solo and ensemble musical performance. The first study examined flute and clarinet performers in both solo and duo settings. Whilst each player had a specific way of expressing musical goals through their bodily movement, there were features common to the woodwind instruments investigated. Detailed analyses revealed that, although many movements were possible, performers used only six basic expressive gesture types. The second study described a performance of the internationally celebrated pianist, Lang Lang, focusing on the relationship between musical affect, bodily movement and facial expression. Analysis also revealed extensive and striking use of combined bodily and facial expression, which were involved in articulating structural features of the music and the narrative of the work. Findings suggest the existence of a repertoire of expressive information used for the generation of expressive ideas, and available to the observers of music performers.
•Buoyancy driven flow, heat and mass transfer in 3D fiber structures are simulated.•P-NDLBM and CSGS are used to show effects of porosity, diameter, and thickness.•Mesoscopic scale velocity, ...temperature, and concentration distributions are shown.•Three dimensional mesoscopic scale spiral flows enhance heat and mass transfer.
Three dimensional (3D) buoyancy driven fluid flow, heat and mass transfer through a vertical board with structures of randomly packed fibers are simulated by a non-dimensional lattice Boltzmann method (NDLBM). The two outside walls in the board transverse direction are fixed with opposing constant temperature and species concentration. The outside walls in the longitudinal directions are adiabatic. Varying board porosities, fiber diameters, and board thicknesses are generated by a controllable structure generation scheme (CSGS). The NDLBM simulations with D3Q27 grids show 3D velocity, temperature and concentration fields in the mesoscopic scale. The effects of board porosity, fiber diameter, and board thickness are quantified. The results show that the trends of macroscopic Nusselt, Sherwood, and Biot numbers with macroscopic porosity are similar to previous 2D random structure simulations, but the 3D fiber structures are more effective for both heat and mass transfer compared to 2D random structures with equivalent governing parameters. The difference in transfer properties is attributed to mesoscopic flow patterns. The mesoscopic 3D spiral flow is due to the 3D vortex generated by local fiber boundaries. The stagnation points of the 3D spiral structures usually appear at relative higher local porosity positions. The 3D spirals enhance the pore scale heat mass transfer.
A recent surge of research has begun to examine music participation and well-being; however, a particular challenge with this work concerns theorizing around the associated well-being benefits of ...musical participation. Thus, the current research used Self-Determination Theory to consider the potential associations between basic psychological needs (competence, relatedness, and autonomy), self-determined autonomous motivation, and the perceived benefits to well-being controlling for demographic variables and the musical activity parameters. A sample of 192 Australian residents (17-85,
= 36.95), who were currently participating in a musical activity at the time, completed an online questionnaire. Results indicated that females were more likely to perceive benefits to their well-being; and that how important an individual considers music in their life was positively related to perceived well-being. Importantly, the analyses also revealed that the basic needs of competency and relatedness were related to overall perceived well-being as well as specifically social, cognitive, and esteem dimensions of well-being. Autonomous motivation demonstrated significant associations with both an overall well-being score as well as four of five specific well-being subscales measured. Collectively, the findings indicate that Self-Determination Theory offers a useful theoretical framework to understanding the relationship between musical participation and well-being. Further, the pattern of findings reiterates the positive associations between musical participation and one's psychosocial well-being, with broad implications for people involved in the facilitation of musical activity.
Social isolation and loneliness are serious public health concerns. Music engagement can strengthen social connections and reduce loneliness in some contexts, although how this occurs is not well ...understood; research suggests that music's capacity to manipulate perceptions of time and space is relevant. This study adopted a qualitative perspective to examine how music engagement shaped the experiences of residents of Victoria, Australia, during conditions of restricted social contact during the lockdowns of 2020. Semi-structured interviews explored participants' lived musical experiences while giving focus to perceptions of time and space (e.g., how music helped restructure home and workspaces in response to lockdown regulations, or punctuate time where older routines were no longer viable). Interpretative Phenomenological Analysis of the interview transcripts identified five themes representing the key findings: (1) a super-ordinate theme of perceived control, which comprises four themes: (2) dynamic connection; (3) identity; (4) mobility; (5) presence. Each theme describes one generalised aspect of the way music engagement shaped participants' perceptions of time and space during lockdown and supported their processes of adaptation to and coping with increased social isolation. The authors argue that these findings may inform the way music can be used to address loneliness in everyday life.
High efficiency solar chemical-looping methane reforming is demonstrated in a prototype reactor operated in a high-flux solar simulator. The reactor includes six tube assemblies, which each comprise ...a fixed-bed of ceria particles and a gas-phase heat recuperator. The cycle was accomplished by alternating the flow to one tube assembly between CH4 and CO2. In the initial series of experiments, temperature, CH4 concentration, reduction flow rate, and cycle duration were varied to minimize carbon accumulation and maximize efficiency. In the second set of tests, the reactor was operated at optimized conditions for ten cycles at 1228 and 1274 K. Higher temperature favors better performance. At 1274 K, CH4 conversion is 0.36, H2 selectivity is 0.90, CO selectivity is 0.82, CO2 conversion is 0.69, and the energetic upgrade factor is 1.10. Heat recovery effectiveness is over 95%. Solar-to-fuel efficiency is 7% and the thermal efficiency is 25%. Projected solar-to-fuel and thermal efficiencies are 31 and 67% for the full-scale reactor and 56 and 85% for a commercial reactor with lower thermal losses. The demonstrated efficiencies are the highest reported to-date for this process. The projected scaled-up efficiencies suggest solar chemical-looping methane reforming could be a competitive approach for production of solar fuels.
•Chemical-looping methane reforming with ceria is performed in a solar reactor.•At 1274 K, solar-to-fuel efficiency is 7% with 1/6th of the reactor capacity.•CH4 conversion is 0.36 with H2 and CO selectivities of 0.90 and 0.82.•Gas-phase heat recovery effectiveness is above 95%.•The scaled-up solar-to-fuel efficiency is predicted to be 31%.
•Thermodynamics of solar chemical looping reforming is presented.•Conversions and selectivities are key performance parameters.•Ideal solar to fuel efficiency is 54% at 1273K and 1000 suns.•Prior ...studies of oxygen carrier materials are reviewed.•Ceria and perovskites are promising materials for further study.
The potential of solar thermal chemical-looping reforming for efficient and sustainable co-production of synthesis gas and hydrogen is discussed. In an endothermic partial oxidation step, methane reacts with oxygen released from a metal oxide to produce hydrogen and carbon monoxide. In an exothermic second step, steam reacts with the reduced metal oxide to produce hydrogen. This review summarizes the process and chemical thermodynamic foundations of solar chemical-looping reforming and provides a synopsis of materials studies that reflect the state of knowledge in 2017. The challenges and opportunities for future research and development are discussed.
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