Time filter

Source Type

Chiba, Japan

Miyazaki T.,Tokyo University of Agriculture and Technology | Miyazaki T.,Kyushu University | Akisawa A.,Tokyo University of Agriculture and Technology | Nikai I.,Engineering Consultant
Energy and Buildings

The solar chimney is a passive cooling technique to enhance the natural ventilation of buildings. The effect is, however, limited under hot and humid climatic conditions. In the study, the solar chimney was accompanied by a dew-point evaporative cooler. The dew-point evaporative cooler was integrated with the ceiling of a building. The air flow induced by the solar chimney was predicted by simulation, and the cooling effect of the dew-point evaporative cooler was also analyzed by heat and mass transfer simulation. The results showed that the system was capable of coping with internal heat gains of an ordinary office building. In addition, the optimal geometry of the evaporative cooling channel was revealed. © 2011 Elsevier B.V. All rights reserved. Source

Weiss S.,Austrian Center of Industrial Biotechnology | Somitsch W.,Engineering Consultant | Somitsch W.,IPUS Mineral und Umwelttechnologie GmbH | Klymiuk I.,Medical University of Graz | And 3 more authors.
Bioresource Technology

Mixed fermentative/hydrolytic bacteria were enriched on lignocellulose substrates in minimal medium under semi-anaerobic mesophilic conditions in the presence or absence of natural zeolite as growth supporter to ultimately bioaugment non-adapted sludge and thereby enhance the overall anaerobic digestion (AD) of recalcitrant plant material. Desired enzyme activities, i.e. xylanases and cellulase were monitored during subsequent cultivation cycles. Furthermore, enriched microbial communities were characterized by 16S rRNA-based 454-Pyrosequencing, revealing Firmicutes, Bacteriodetes, Proteobacteria and Spirochaetes to be the predominant bacterial groups in cultures derived from anaerobic sludge and raw crop material, i.e. maple green cut and wheat straw as well. Enriched populations relevant for biopolymer hydrolysis were then compared in biological methane potential tests to demonstrate positive effects on the biogasification of renewable plant substrate material. A significant impact on methane productivity was observed with adapted mixed cultures when used in combination with clinoptilolite to augment and supplement non-adapted bioreactor sludge. © 2016. Source

Shrekenhamer A.,Engineering Consultant | Gottesman S.R.,Northrop Grumman
Proceedings of SPIE - The International Society for Optical Engineering

A novel and memory efficient method for computing diffraction patterns produced on large-scale focal planes by largescale Coded Apertures at wavelengths where diffraction effects are significant has been developed and tested. The scheme, readily implementable on portable computers, overcomes the memory limitations of present state-of-the-art simulation codes such as Zemax. The method consists of first calculating a set of reference complex field (amplitude and phase) patterns on the focal plane produced by a single (reference) central hole, extending to twice the focal plane array size, with one such pattern for each Line-of-Sight (LOS) direction and wavelength in the scene, and with the pattern amplitude corresponding to the square-root of the spectral irradiance from each such LOS direction in the scene at selected wavelengths. Next the set of reference patterns is transformed to generate pattern sets for other holes. The transformation consists of a translational pattern shift corresponding to each hole's position offset and an electrical phase shift corresponding to each hole's position offset and incoming radiance's direction and wavelength. The set of complex patterns for each direction and wavelength is then summed coherently and squared for each detector to yield a set of power patterns unique for each direction and wavelength. Finally the set of power patterns is summed to produce the full waveband diffraction pattern from the scene. With this tool researchers can now efficiently simulate diffraction patterns produced from scenes by large-scale Coded Apertures onto large-scale focal plane arrays to support the development and optimization of coded aperture masks and image reconstruction algorithms. © 2012 SPIE. Source

Guthrie M.,Engineering Consultant | Rousseau A.,SEFTIM Vincennes
AIChE Annual Meeting, Conference Proceedings

Lightning can pose a myriad of threats to operations involving flammable vapors and liquids that give off flammable vapors. This paper focuses primarily on storage facilities and associated operations but the principles can be applied to any operation or installation where a flammable environment may exist. General principles of protection from a lightning threat are provided, along with a discussion of specific threats presented by operations in which flammable vapors may be present. The evolution of protection considerations is also discussed. Techniques for protection from direct attachment are provided to address those situations where an external flammable vapor could exist in the vicinity of a storage vessel. Threats produced by nearby lightning and strikes to associated piping and electrical conduits are also addressed. The elimination of both external and internal potential differences that could lead to dangerous arcing is discussed. This paper also provides a discussion of the difference in grounding system impedance versus static grounding techniques as they relate to the dissipation of lightning currents and explains their significance in minimizing the probability of arcing between structural components and systems. The principles discussed are summarized in the context of the development of a lightning protection plan. Source

Rousseau A.,SEFTIM | Sainte-Rose-Fanchine C.,SEFTIM | Guthrie M.,Engineering Consultant
2015 International Symposium on Lightning Protection, XIII SIPDA 2015

The 2nd edition of the lightning risk assessment standard (IEC 62305-2) considers structures which may endanger the environment. In these cases, the loss is not limited to the structure itself; which is the case for 'usual' structures. In Edition 1 of the standard this danger was simply taken into account by multiplying the calculated risk for the structure by a special hazard factor. In Edition 2, the calculated risk for the structure itself is added to another risk associated with the losses outside of the structure. The losses outside can be treated independently from what occurs inside. This is a major advantage in the analysis of the risk for sensitive structures such as chemical plants, nuclear plants, or structures containing explosives, etc. Edition 3 of the standard is currently under preparation. It is important to better define what the environmental risk really is and how it can be calculated efficiently. A methodology proposed in previous publications has been adapted to real cases already studied with Edition 1 of IEC 62305-2 for comparison. © 2015 IEEE. Source

Discover hidden collaborations