1,721,113 research outputs found
Releasing an Educational Android App
Full text linkThis paper explores the process and challenges of creating an educational app for android devices. The Heat Loss Calculator app was initially conceived to allow researchers to quickly calculate building heat loss by entering the U-values of different building element fabrics. Selecting lower U-values equates to the various insulation improvements which can potentially reduce heat loss and improve energy efficiency. During early development it became clear that the app would also be a useful learning tool for students. Therefore, it was designed with this wider audience in mind, with the intention of publishing it in the public domain. Issues encountered during development and some that became apparent after release on the Google Play Store will be discussed. The user experience will be evaluated by means of an online survey of students and by using the app in a group session in the classroom. The feedback will be examined to inform how the app can be improved
Electron kinetics of collision dominated r.f. bulk plasma in CO: The role of second-kind collisions
No full textElectron energy distribution functions (EEDF) and related properties in the bulk region of the rf CO plasma at the reduced rf field frequency ohgr/p0=pgr×107 sec–1 torr–1 have been calculated by solving the time-dependent spatially homogeneous Boltzmann equation in the presence of second-kind collisions and have been interpreted on a microphysical basis. The results show that second-kind collisions (vibrational and electronic) strongly affect the temporal evolution of EEDF, of the mean energy, and of the mean collision frequencies for vibrational and electronic excitation processes, as well as for ionization. In particular, second-kind collisions in the CO rf bulk plasma strongly decrease the modulation of the mean ionization frequency during its periodical alteration in the rf field. Furthermore, the effect of second-kind collisions on an approximate determination of the time-averaged EEDF in the rf bulk plasma using the so-called effective-field appriximation has been estimated
Transport Properties of High Temperature Air in Local Thermodynamic Equilibrium
No full textIn the paper calculated transport coefficients of air in the temperature range 50 K - 100,000 K are presented. The results have been obtained by means of the perturbative Chapman-Enskog method, assuming that the plasma is in local thermodynamic equilibrium (LTE). The calculations include viscosity, thermal conductivity, electric conductivity and multicomponent diffusion coefficients. For the calculation, a recent compilation of collision integrals obtained by Capitelli et al. [1] has been utilized
Transport properties of high temperature air components: A review
No full textThe methods for the calculation of the transport properties of high temperature gases are reviewed from the points of view of both kinetic theory and transport cross sections. Particular emphasis is given to the poor convergence of the Chapman-Enskog method for calculating the thermal conductivity of free electrons and of the possible sources of errors when applying well known simplified formulae for calculating the translational thermal conductivity of heavy components and the viscosity of partially ionized gases. The transport cross sections (collision integrals) of high temperature air components are then discussed by comparing old and new calculations particularly emphasizing atom-atom, atom-molecule and atom-ion interactions. Special consideration is dedicated to the knowledge of transport cross sections of electronically excited states. The role of inelastic processes in affecting the transport cross sections is also briefly discussed. Finally the possibility to extend the results to non equilibrium situations is analysed
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