Electrical Loads and Power Systems for the DEMO Nuclear Fusion Project

EU-DEMO is a European project, having the ambitious goal to be the first demonstrative power plant based on nuclear fusion. The electrical power that is expected to be produced is in the order of 700–800 MW, to be delivered via a connection to the European High Voltage electrical grid. The initiation and control of fusion processes, besides the problems related to the nuclear physics, need very complex electrical systems. Moreover, also the conversion of the output power is not trivial, especially because of the inherent discontinuity in the EU-DEMO operations. The present article concerns preliminary studies for the feasibility and realization of the nuclear fusion power plant EU-DEMO, with a special focus on the power electrical systems. In particular, the first stage of the study deals with the survey and analysis of the electrical loads, starting from the steady-state loads. Their impact is so relevant that could jeopardy the efficiency and the convenience of the plant itself. Afterwards, the loads are inserted into a preliminary internal distribution grid, sizing the main electrical components to carry out the power flow analysis, which is based on simulation models implemented in the DIgSILENT PowerFactory software

Movie subtitles reading skills of elementary school children

TEMA: as habilidades de leitura de textos fixos em escolares são amplamente conhecidas, no entanto ainda não se sabe como os escolares realizam a leitura de textos móveis e quais habilidades são necessárias para este tipo de leitura. OBJETIVO : avaliar as habilidades de leitura de legendas de filmes em escolares de segunda e quarta série do ensino fundamental de uma escola pública. MÉTODO: análise do nível e habilidades de leitura de legenda de filmes, por meio da recontagem de um trecho de filme assistido, de forma individual, sem som e com legenda, por 60 escolares, sendo 30 de segunda série e 30 de quarta série, pareados quanto ao gênero e idade. RESULTADOS: não foram encontradas diferenças significantes quanto aos níveis de letramento escolar entre as duas séries. Quanto às habilidades e ao nível de leitura de legenda de filmes os escolares de quarta série obtiveram desempenho significativamente superior aos de segunda série, uma vez que apresentaram habilidades referentes aos níveis de compreensão literal e compreensão independente, enquanto os de segunda série, em média ficaram no nível de decodificação. CONCLUSÃO: os escolares de segunda série estão em nível de decodificação, enquanto os de quarta série encontram-se em nível de compreensão literal de leitura de legenda de filmes, demonstrando que a escolaridade influencia a leitura de legenda de filmes. Entretanto, o grau de letramento escolar não foi um fator significante para a leitura de legenda de filmes.BACKGROUND: the abilities of school children for reading static texts have been widely discussed, however little is known about how well they can read dynamic texts and what skills are required for this kind of reading. AIM: to evaluate the skills involved in reading movie subtitles of 2nd and 4th graders of students at the a public school. METHOD: analysis of the level and skills needed for movie subtitles reading, through the retelling of a section of a movie watched individually by 60 students, 30 2nd graders and 30 4th graders matched for age and gender, with no sound and with subtitles. RESULTS: there were no significant differences in the level of school literacy between students of the different school grades. Considering the skills and the subtitles reading level, 4th graders presented a significant better performance when compared to the 2nd graders. Fourth graders presented skills related to the levels of literal comprehension and independent comprehension, whereas 2nd graders where mostly at the decoding level. CONCLUSION: 2nd graders are at the textual decoding level of movie subtitles, while 4th graders are at the literal comprehension level of movie subtitles. This indicates that schooling has an influence on the reading of movie subtitles. However, the school literacy literacy was not a significant factor for movie subtitles reading

ON THE INFLUENCE OF CHANNEL TORTUOSITY ON ELECTRIC FIELDS GENERATED BY LIGHTNING RETURN STROKES AT CLOSE DISTANCE

In this paper the results of the estimated electric field associated with tortuous lightning paths at close distance (50 m to 500 m) are shown. Such results are compared with experimental data available in the literature and are illustrated along with a quantitative analysis of the field waveforms and their frequency spectra. The limits of the usual straight-vertical channel assumption and the influence of tortuosity at different azimuth and distances from the lightning channel base are also highlighted

Apollo Lightcraft Project

This second year of the NASA/USRA-sponsored Advanced Aeronautical Design effort focused on systems integration and analysis of the Apollo Lightcraft. This beam-powered, single-stage-to-orbit vehicle is envisioned as the shuttlecraft of the 21st century. The five person vehicle was inspired largely by the Apollo Command Module, then reconfigured to include a new front seat with dual cockpit controls for the pilot and co-pilot, while still retaining the 3-abreast crew accommodations in the rear seat. The gross liftoff mass is 5550 kg, of which 500 kg is the payload and 300 kg is the LH2 propellant. The round trip cost to orbit is projected to be three orders of magnitude lower than the current space shuttle orbiter. The advanced laser-driven 5-speed combined-cycle engine has shiftpoints at Mach 1, 5, 11 and 25+. The Apollo Lightcraft can climb into low Earth orbit in three minutes, or fly to any spot on the globe in less than 45 minutes. Detailed investigations of the Apollo Lightcraft Project this second year further evolved the propulsion system design, while focusing on the following areas: (1) man/machine interface; (2) flight control systems; (3) power beaming system architecture; (4) re-entry aerodynamics; (5) shroud structural dynamics; and (6) optimal trajectory analysis. The principal new findings are documented. Advanced design efforts for the next academic year (1988/1989) will center on a one meter+ diameter spacecraft: the Lightcraft Technology Demonstrator (LTD). Detailed engineering design and analyses, as well as critical proof-of-concept experiments, will be carried out on this small, near-term machine. As presently conceived, the LTD could be constructed using state of the art components derived from existing liquid chemical rocket engine technology, advanced composite materials, and high power laser optics

Apollo Lightcraft Project

The ultimate goal for this NASA/USRA-sponsored Apollo Lightcraft Project is to develop a revolutionary manned launch vehicle technology which can potentially reduce payload transport costs by a factor of 1000 below the Space Shuttle Orbiter. The Rensselaer design team proposes to utilize advanced, highly energetic, beamed-energy sources (laser, microwave) and innovative combined-cycle (airbreathing/rocket) engines to accomplish this goal. The research effort focuses on the concept of a 100 MW-class, laser-boosted Lightcraft Technology Demonstrator (LTD) drone. The preliminary conceptual design of this 1.4 meter diameter microspacecraft involved an analytical performance analysis of the transatmospheric engine in its two modes of operation (including an assessment of propellant and tankage requirements), and a detailed design of internal structure and external aeroshell configuration. The central theme of this advanced propulsion research was to pick a known excellent working fluid (i.e., air or LN sub 2), and then to design a combined-cycle engine concept around it. Also, a structural vibration analysis was performed on the annular shroud pulsejet engine. Finally, the sensor satellite mission was examined to identify the requisite subsystem hardware: e.g., electrical power supply, optics and sensors, communications and attitude control systems

Hyperbolic Equations and General Relativity

This is the author Master's Thesis and its main purpose is to demonstrate that it is possible to formulate Einstein's field equations as an initial value problem. The first chapter concerns the hyperbolic equations theory. The definition of hyperbolic equation is given and the concept of wavelike propagation is presented. Hence, once Riemann kernel definition is given, Riemann method to solve an hyperbolic equation in two variables is showed. The second chapter is about the fundamental solution and its relation to Riemann kernel. Therefore, the study of the fundamental solutions proceeds by showing how to build them and by providing some examples of solution with odd and even number of variables. In chapter four, by following Foures-Bruhat, the problem of finding a solution to the Cauchy problem for Einstein field equations in vacuum with non analytic initial data is presented by studying under which assumptions second-order systems of partial differential equations, linear and hyperbolic, with n functions and four variables admit a solution. Thus, in chapter five, it is showed how to turn non-linear systems of partial differential equations into linear systems of the same type for which the previous results hold. Eventually, in chapter six, the existence and uniqueness of the solution to the Cauchy problem for Einstein vacuum field equations is proved. Another part of this work consists in the study of the causal structure of space-time. The definitions of strong causality, stable causality and global hyperbolicity are given and the relation between the property of global hyperbolicity and the existence of Cauchy surfaces is stressed. The last chapter concerns the study of gravitational radiation in axisymmetric black hole collisions at the speed of light as an useful application of Riemann kernel method to solve a second-order hyperbolic equation in two variables.Comment: 233 pages, 7 figures. arXiv admin note: text overlap with arXiv:gr-qc/9506088, arXiv:gr-qc/0101076, arXiv:gr-qc/0607134, arXiv:1801.01714, arXiv:1410.3971, arXiv:astro-ph/0504599 by other author

Mathematical Modeling of Lung Inflammation: Macrophage Polarization and Ventilator-Induced Lung Injury with Methods for Predicting Outcome

Lung insults, such as respiratory infections and lung injuries, can damage the pulmonary epithelium, with the most severe cases needing mechanical ventilation for effective breathing and survival. Furthermore, despite the benefits of mechanical ventilators, prolonged or misuse of ventilators may lead to ventilation-associated/ventilation-induced lung injury (VILI). Damaged epithelial cells within the alveoli trigger a local immune response. A key immune cell is the macrophage, which can differentiate into a spectrum of phenotypes ranging from pro- to anti-inflammatory. To gain a greater understanding of the mechanisms of the immune response in the lungs and possible outcomes, we developed several mathematical models of interactions between immune system components and site of damage while accounting for macrophage polarization. We analyzed these models to highlight the parameters and corresponding biological mechanisms that drive outcome and to make predictions about lung health. We developed a set of ordinary differential equations (ODEs) to model VILI and utilized parameter sampling to evaluate how baseline immune state and lung health, as well as response to tissue damage, affect post-ventilation outcomes. We used a variety of methods to analyze the resulting parameter sets, transients, and outcomes. Analysis showed that parameters and properties of transients related to epithelial repair and M1 activation are important factors. We then used this collection of parameter sets to generate synthetic data and developed algorithms that utilize this collection to predict lung health outcomes based on early time-point data. Our results were comparable to logistic regression and random forest classification methods, and we performed several case studies to highlight how our methods can be used. Finally, we used different modeling techniques, ODE modeling and agent-based modeling (ABM), to simulate the spectrum of macrophage activation to general pro- and anti-inflammatory stimuli on an individual cell level. The ODE model includes two hallmark pro- and anti-inflammatory signaling pathways and the ABM incorporates similar M1-M2 rules but in a spatio-temporal platform. We then performed simulations with various initial conditions to replicate different experimental setups. Comparing the two models\u27 results sheds light on the important features of each modeling approach. In the future, when more data is available, these features can be considered when choosing techniques to best fit the needs of the modeler and application