7,363 research outputs found
Study of component technologies for fuel cell on-site integrated energy system. Volume 2: Appendices
This data base catalogue was compiled in order to facilitate the analysis of various on site integrated energy system with fuel cell power plants. The catalogue is divided into two sections. The first characterizes individual components in terms of their performance profiles as a function of design parameters. The second characterizes total heating and cooling systems in terms of energy output as a function of input and control variables. The integrated fuel cell systems diagrams and the computer analysis of systems are included as well as the cash flows series for baseline systems
Study of component technologies for fuel cell on-site integrated energy systems
Heating, ventilation and air conditioning equipment are integrated with three types of fuel cells. System design and computer simulations are developed to utilize the thermal energy discharge of the fuel in the most cost effective manner. The fuel provides all of the electric needs and a loss of load probability analysis is used to ensure adequate power plant reliability. Equipment cost is estimated for each of the systems analyzed. A levelized annual cost reflecting owning and operating costs including the cost of money was used to select the most promising integrated system configurations. Cash flows are presented for the most promising 16 systems. Several systems for the 96 unit apartment complex (a retail store was also studied) were cost competitive with both gas and electric based conventional systems. Thermal storage is shown to be beneficial and the optimum absorption chiller sizing (waste heat recovery) in connection with electric chillers are developed. Battery storage was analyzed since the system is not electric grid connected. Advanced absorption chillers were analyzed as well. Recommendations covering financing, technical development, and policy issues are given to accelerate the commercialization of the fuel cell for on-site power generation in buildings
Perceiving animacy from shape
Superordinate visual classification—for example, identifying an image as “animal,” “plant,” or “mineral”—is computationally challenging because radically different items (e.g., “octopus,” “dog”) must be grouped into a common class (“animal”). It is plausible that learning superordinate categories teaches us not only the membership of particular (familiar) items, but also general features that are shared across class members, aiding us in classifying novel (unfamiliar) items. Here, we investigated visual shape features associated with animate and inanimate classes. One group of participants viewed images of 75 unfamiliar and atypical items and provided separate ratings of how much each image looked like an animal, plant, and mineral. Results show systematic tradeoffs between the ratings, indicating a class-like organization of items. A second group rated each image in terms of 22 midlevel shape features (e.g., “symmetrical,” “curved”). The results confirm that superordinate classes are associated with particular shape features (e.g., “animals” generally have high “symmetry” ratings). Moreover, linear discriminant analysis based on the 22-D feature vectors predicts the perceived classes approximately as well as the ground truth classification. This suggests that a generic set of midlevel visual shape features forms the basis for superordinate classification of novel objects along the animacy continuum
Humoral response in a patient with cutaneous nocardiosis
The clinical appearance of infection due to Nocardia spp. varies widely. The law sensitivity of direct microscopy and the slow growth of the organism challenge the laboratory diagnosis. We present the case of a skin abscess in an immunocompetent man caused by Nocardia brasiliensis. Diagnosis was made by cultivation and 16S rRNA sequencing. Using indirect immunofluorescence and Western blot, a strong antibody response to the N. brasiliensis isolate could be demonstrated. Serological tests might therefore be useful for the diagnosis and management of nocardial infections, copyright (R) 2000 S. Karger AG, Basel
Mechanism for Spontaneous Growth of Nanopillar Arrays in Ultrathin Films Subject to a Thermal Gradient
Several groups have reported spontaneous formation of periodic pillar-like
arrays in molten polymer nanofilms confined within closely spaced substrates
maintained at different temperatures. These formations have been attributed to
a radiation pressure instability caused by acoustic phonons. In this work, we
demonstrate how variations in the thermocapillary stress along the nanofilm
interface can produce significant periodic protrusions in any viscous film no
matter how small the initial transverse thermal gradient. The linear stability
analysis of the interface evolution equation explores an extreme limit of
B\'{e}nard-Marangoni flow peculiar to films of nanoscale dimensions in which
hydrostatic forces are altogether absent and deformation amplitudes are small
in comparison to the pillar spacing. Finite element simulations of the full
nonlinear equation are also used to examine the array pitch and growth rates
beyond the linear regime. Inspection of the Lyapunov free energy as a function
of time confirms that in contrast to typical cellular instabilities in
macroscopically thick films, pillar-like elongations are energetically
preferred in nanofilms. Provided there occurs no dewetting during film
deformation, it is shown that fluid elongations continue to grow until contact
with the cooler substrate is achieved. Identification of the mechanism
responsible for this phenomenon may facilitate fabrication of extended arrays
for nanoscale optical, photonic and biological applications.Comment: 20 pages, 9 figure
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