1,357 research outputs found
Space and the nation: three texts on Aldo Rossi
No full textIn this paper the spatial dimensions of political practice and the historical dimensions of architectural practice are examined. The author argues that these two practices intersect when, in the life of a city and a nation, time is transformed into space. The productivity of death in this regard is explored. In developing this argument, reference is made to the works and writings of Regis Debray and Aldo Rossi, as well as events in the recent political history of South Africa
Foul Air: Aldo van Eyck on Postmodern Architecture
No full textIntroduction to bookGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Space & Typ
Multi-Scale Modelling of a Solar Reactor for the High-Temperature Step of a Sulphur-Iodine-Based Water Splitting Cycle
Full text linkThe 3-step sulphur-iodine-based thermochemical cycle for splitting water is considered. The high temperature step of the closed-material cycle consists of evaporation, decomposition, and reduction of sulphuric acid to SO2 using concentrated solar process heat. This step is followed by the Bunsen reaction and HI decomposition. The solar reactor concepts proposed are based on a shell-and-tube heat exchanger filled with catalytic packed beds and on a porous ceramic foam to directly absorb solar radiation and act as reaction site. The design, modelling and optimisation of the solar reactor using complex porous structures relies on the accurate determination of their effective heat and mass transport properties. Accordingly, a multi-scale approach is applied. Ceramic foam samples are imaged using high-resolution X-ray tomography to obtain their exact 3D geometrical configuration, which in turn is used in direct pore-level simulations for the determination of the morphological and effective transport properties. These are incorporated in a volume-averaged (continuum) model of the solar reactor. Model validation is accomplished by comparing numerically simulated and experimentally measured temperatures in a 1 kW reactor prototype tested in a solar furnace. The model is further applied to analyze the influence of foam properties, reactor geometry, and operational conditions on the reactor performance
Experimental High-Frequency Parameter Identification of AC Electrical Motors
Full text linkIn order to predict conducted electromagnetic interference in inverter-motor drive systems, high-frequency (HF) motor models are requested and the involved parameters have to be available. In previous studies, the authors have presented an accurate HF model for induction motors and they have defined the procedures to identify the model parameters. In this paper, these results are extended to several types and sizes of industrial ac motors such as induction, synchronous reluctance (without interior permanent magnets), and brushless motors. The model parameter-identification procedure has been improved, and it is based on a least-squares data fitting applied to the measured magnitude and phase-frequency-response curves of the phase-to-ground and the phase-to-neutral impedances. The aim of this paper is to provide quick indications to select the suitable values of the HF model parameters, with reference to the size and type of the ac motor, to evaluate the HF voltage and current components in inverted-fed ac motor system
The Italy of Aldo Moro
Full text linkСтатья посвящена истории христианско-демократической партии Италии. Рассматриваются проблемы формирования взглядов христианско-демократического политика Альдо Моро, идеология реформ правительства левого центра, их значение в истории Италии.The article focused on the problem of formation of the conceptions of Aldo Moro, the leader of the Christian-democratic party of Italy. The author defines the results of its implementation in Italy
The Italy of Aldo Moro
No full textСтатья посвящена истории христианско-демократической партии Италии. Рассматриваются проблемы формирования взглядов христианско-демократического политика Альдо Моро, идеология реформ правительства левого центра, их значение в истории Италии.The article focused on the problem of formation of the conceptions of Aldo Moro, the leader of the Christian-democratic party of Italy. The author defines the results of its implementation in Italy
Solar-driven alumina calcination for CO(2) mitigation and improved product quality
Full text linkAccepted 10th May 2017We report on the first-of-a-kind experimental demonstration of the calcination of alumina with concentrated solar thermal (CST) radiation at radiative fluxes up to 2190 suns using a 5 kW novel solar transport reactor. Aluminium hydroxide was calcined at nominal reactor temperatures over the range 1160–1550 K to yield chemical conversions of up to 95.8% for nominal residence times of approximately 3 s. Solar energy conversion efficiencies of up to 20.4% were achieved. The mean pore diameter and specific surface area of the solar-generated alumina with the greatest chemical conversion were 5.8 nm and 132.7 m² g⁻¹, respectively, which are higher values than are typical for industrial alumina production. In addition, the product is dominated by the γ-phase, which is desirable for the downstream processing to aluminium. This suggests that CST can improve the quality of alumina over existing fossil fuel based processes though a combination of a high heating rate and avoided contamination by combustion products. Furthermore, the solar-driven process has the potential to avoid the discharge of combustion-derived CO₂ emissions for the calcination stage of the conventional Bayer process, which is typically 165 kg-CO₂ per tonne-alumina.Dominic Davis, Fabian Müller, Woei L. Saw, Aldo Steinfeld and Graham J. Natha
Infrared-Reflective Coating on Fused Silica for a Solar High-Temperature Receiver
No full textIn concentrating solar power, high-temperature solar receivers can provide heat to highly efficient cycles for electricity or chemical production. Excessive heating of the fused-silica window and the resulting recrystallization are major problems of high-temperature receivers using windows. Excessive window temperatures can be avoided by applying an infrared-reflective solar-transparent coating on the fused-silica window inside. Both glass temperatures and receiver losses can be reduced. An ideal coating reflects part of the thermal spectrum (lambda>2.5 µm) of the hot absorber (1100°C) back onto it without reducing solar transmittance. Extensive radiation simulations were done to screen different filter types. The examined transparent conductive oxides (TCO) involve a high solar absorptance, inhibiting their use in high-concentration solar systems. Although conventional dielectric interference filters have a low solar absorption, the reflection of solar radiation which comes from various directions is too high. It was found that only rugate filters fulfill the requirements for operation under high-flux solar radiation with different incident angles. A thermodynamic qualification simulation of the rugate coating on a window of a flat-plate receiver showed a reduction of almost 175 K in mean window temperature and 11% in receiver losses compared to an uncoated window. For the configuration of a pressurized receiver (REFOS type), the temperature could be reduced by 65 K with slightly reduced receiver losses. Finally, a first 25-µm thick rugate filter was manufactured and optically characterized. The measured spectra fitted approximately the design spectra, except for two absorption peaks which can be avoided in future depositions by changing the deposition geometry and using in-situ monitoring. The issue of this paper is to share the work done on the choice of filter type, filter design, thermodynamic evaluation, and deposition experiments
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