• Energy Research
• Closed Access close
• Restricted close
• Open Source close
• IT close
• FR close
• Aurora Universities Network close

------------------------------------------------------------------------------------------------------------------------------------------- This version has been superseded. The latest version is at https://doi.org/10.5281/zenodo.5517550 ------------------------------------------------------------------------------------------------------------------------------------------- Eddy covariance flux tower datasets of all Urban-PLUMBER sites, associated with the manuscript: "Harmonized, gap-filled dataset from 20 urban flux tower sites" Use of any data must give credit through citation of the above manuscript and other sources as appropriate. We recommend data users consult with site contributing authors and/or the coordination team in the project planning stage. Relevant contacts are included in timeseries metadata. For site information and timeseries plots see https://urban-plumber.github.io/sites. For processing code see https://github.com/matlipson/urban-plumber_pipeline. Within each site folder: - `index.html`: A summary page with site characteristics and timeseries plots. - `SITENAME_sitedata_vX.csv`: comma seperated file for numerical site characteristics e.g. location, surface cover fraction etc. - `timeseries/` (following files available as netCDF and txt) - `SITENAME_raw_observations_vX`: site observed timeseries before project-wide quality control. - `SITENAME_clean_observations_vX`: site observed timeseries after project-wide quality control. - `SITENAME_metforcing_vX`: site observed timeseries after project-wide quality control and gap filling. - `SITENAME_era5_corrected_vX`: site ERA5 surface data (1990-2020) with bias corrections as applied in the final dataset. - `log_processing_SITENAME_vX.txt`: a log of the print statements through running the create_dataset_SITENAME scripts. Authors Mathew Lipson, Sue Grimmond, Martin Best, Andreas Christen, Andrew Coutts, Ben Crawford, Bert Heusinkveld, Erik Velasco, Helen Claire Ward, Hirofumi Sugawara, Je-Woo Hong, Jinkyu Hong, Jonathan Evans, Joseph McFadden, Keunmin Lee, Krzysztof Fortuniak, Leena Järvi, Matthias Roth, Nektarios Chrysoulakis, Nigel Tapper, Oliver Michels, Simone Kotthaus, Stevan Earl, Sungsoo Jo, Valéry Masson, Winston Chow, Wlodzimierz Pawlak, Yeon-Hee Kim. Corresponding author: Mathew Lipson <m.lipson@unsw.edu.au>

Abstract The technical and economic feasibility of a single-stage water-sulphuric acid heat transformer, as evaluated through a simplified mathematical model, is discussed in this paper. Three different criteria of optimality are considered. The first two respectively account for the exergetic and the enthalpic value of the useful heat. The third criterion is based on an approximate evaluation of the fixed and operating costs, considered proportional to the inverse of the heat storage capacity. An analysis based on the values of the coefficient of performance and of the mass flow rates, expressed as a function of the gross temperature lift, points out the significance of the criterion based on the heat storage capacity. This result is also supported by considering the ability of the heat transformer to maintain its performance in different external conditions.

Abstract The stack represents the core of standing wave engines since inside it the thermal energy is converted into mechanical energy. Commonly stacks are realized with straight pores whose sections have regular shapes (e.g. circular, rectangular). In these cases the viscous and thermal interactions are described by well-known spatially averaged thermal and viscous functions. Instead, for a materials having tortuous pore, there is a lack in theoretical description of the thermoacoustic phenomenon. This paper deals with the performance of a thermoacoustic engine in which a tortuous porous material is used as stack. The spatially averaged thermal and viscous functions are obtained by classical models used to describe the sound propagation inside a porous material. In particular the Johnson–Champoux–Allard model is considered. It requires the knowledge of five parameters instead of the only hydraulic radius used to describe the standard stack having straight pores (e.g. circular, slit or square pores). The physical meaning of these parameters is explained starting from a straight circular pore and modifying, step by step, the shape of the pore until it becomes tortuous. The proposed functions have been included in the Rott theory and implemented in a numerical procedure. The achieved results are useful to analyse the thermoacoustic performance of a standing wave engine and to understand how the gain factor as well as the viscous and thermal losses inside the stack are affected by the tortuosity. A validation of this procedure is given by comparing the obtained results with ones given by DeltaEC software. This work can be useful to understand the applicability of tortuous porous materials, such as fibrous material as well as open-cell material, for standing wave thermoacoustic engines.

Abstract The attrition of limestone during calcination and sulfation in a fluidized bed reactor is modelled by taking into account the parallel occurrence of abrasion and gas-solid reaction. To this end, the particle is represented as a two-region domain over which equations expressing diffusion and reaction of gaseous reactants and calcium oxide depletion by reaction and attrition are written. Constitutive equations of different complexity are introduced to express the relationship between the attrition rate and the status of the particle surface. Experiments consisting of batchwise calcination and sulfation of limestone samples have been carried out in a bench-scale atmospheric bubbling fluidized bed reactor. Experimental data provided the basis for the evaluation of constitutive parameters and relationships to be embodied in the model. Model computations were directed towards reproducing experimental data points. In spite of its descriptive nature, the model provides useful insight into important features of the interactive processes of sorbent attrition and chemical reactions. First, calcium lost as elutriated fines is made almost entirely of attrited lime, the contribution of sulfate being limited. Second, attrition decays rapidly over a time scale depending on the parallel progress of particle round-off and lime sulfation. In particular, the progress of sulfation dramatically reduces attrition, presumably via the enhancement of particle connectivity and strength associated with the occurrence of ‘molecular cramming’. Third, the ability of attrition to enhance calcium utilization via the removal of impervious sulfate layers which build up at the particle surface is rather limited, at least with the sorbent and under the operating conditions considered in the work.

Human exposure to ionizing radiation is one of the acknowledged potential showstoppers for long duration manned interplanetary missions. Human exploratory missions cannot be safely performed without a substantial reduction of the uncertainties associated with different space radiation health risks, and the development of effective countermeasures. Most of our knowledge of the biological effects of heavy charged particles comes from accelerator-based experiments. During the 35th COSPAR meeting, recent ground-based experiments with high-energy iron ions were discussed, and these results are briefly summarised in this paper. High quality accelerator-based research with heavy ions will continue to be the main source of knowledge of space radiation health effects and will lead to reductions of the uncertainties in predictions of human health risks. Efforts in materials science, nutrition and pharmaceutical sciences and their rigorous evaluation with biological model systems in ground-based accelerator experiments will lead to the development of safe and effective countermeasures to permit human exploration of the Solar System.

A numerical model of cryo-maceration plant for mashed grapes has been realized to simulate the rapid cooling process for mashed grapes according to the number of nozzles enabled to inject CO2, to their flow and temperature of CO2 injected. ANSYS CFX program was used and two geometries have been considered with the axis of each nozzle orthogonal and parallel to the flow direction. Different boundary conditions have been considered. For the models have been considered the most burdensome condition.

Abstract A two-dimensional, unsteady, nonconstant property mathematical model of the degradation of porous cellulosic fuels to volatiles and chars, including convective and conductive heat transfer, is coupled to a quasi-steady, two-dimensional mathematical model, including gas phase momentum, energy and chemical species mass equations, to simulate downward flame spread. Three main regimes of flame spread are established as the fuel thickness is varied. The first, where the spread rate increases with the solid thickness, is observed for a narrow range of very thin solids and is controlled by gas-phase chemical kinetics. In the second regime, the spread rates, which compare favorably with experimental measurements, decrease as the solid thickness is increased (thermally thin regime). Finally, as the fuel thickness is increased beyond a certain limit, the thermally thick regime, that is a constant spread rate, is simulated. Good agreement between the spread rates predicted by the numerical model and the analytical theory by de Ris is obtained in the limit of the thermally thin and thermally thick regime. However, the transition from one regime to the other occurs for largely different fuel thicknesses. The mechanisms of energy feedback to the unburned solid ahead of the flame have also been investigated. Gas-phase heat conduction dominates the first and the second regime of flame spread. The contribution of solid-phase heat conduction to the energy transfer ahead of the flame increases with the fuel thickness reaching, for thermally thick solids, a maximum of about 50% of the total energy transferred.