23,500 research outputs found
Design of fibre reinforced PV concepts for building integrated applications
Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a broad range of the solar spectrum while the material properties and integral production processes create possibilities for novel product concepts with embedded PV technology. To explore such possibilities, innovative design methods were used to design novel PV product concepts for applications in the build environment.\ud
In our paper three conceptual designs are presented; (1) a thin film module with an adjoining interconnection system functioning as structural element for geodetic roofing structures, (2) a PV lamella with single-axis tracking utilizing a linear concentration effect caused by the geometry of the product and the materials applied, and (3) a prepreg PV-material which allows for easy shaping during the production of PV modules with complex geometries. Each concept employs a specific PV technology and demonstrates a possible application aimed at a specific market. In this way we show the potential of integration of PV technology in fibre reinforced composites. The paper will be illustrated by concept renderings
N=8 matter coupled AdS_3 supergravities
Following the recent construction of maximal (N=16) gauged supergravity in
three dimensions, we derive gauged D=3, N=8 supergravities in three dimensions
as deformations of the corresponding ungauged theories with scalar manifolds
SO(8,n)/(SO(8)x SO(n)). As a special case, we recover the N=(4,4) theories with
local SO(4) = SO(3)_L x SO(3)_R, which reproduce the symmetries and massless
spectrum of D=6, N=(2,0) supergravity compactified on AdS_3 x S^3.Comment: 11 pages, LaTeX2
Heat wave and dominant species identity affect bacterial abundance and EPS production in periphyton metacommunities
Integrals over Products of Distributions and Coordinate Independence of Zero-Temperature Path Integrals
In perturbative calculations of quantum-statistical zero-temperature path
integrals in curvilinear coordinates one encounters Feynman diagrams involving
multiple temporal integrals over products of distributions, which are
mathematically undefined. In addition, there are terms proportional to powers
of Dirac delta-functions at the origin coming from the measure of path
integration. We give simple rules for integrating products of distributions in
such a way that the results ensure coordinate independence of the path
integrals. The rules are derived by using equations of motion and partial
integration, while keeping track of certain minimal features originating in the
unique definition of all singular integrals in dimensions. Our
rules yield the same results as the much more cumbersome calculations in 1-
epsilon dimensions where the limit epsilon --> 0 is taken at the end. They also
agree with the rules found in an independent treatment on a finite time
interval.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper (including all PS fonts) at
http://www.physik.fu-berlin.de/~kleinert/33
A numerical study of a method for measuring the effective in situ sound absorption coefficient
The accuracy of a method [Wijnant et al., “Development and applica-
tion of a new method for the in-situ measurement of sound absorption”, ISMA 31,
Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ
sound absorption coefficient is investigated. Based on a local plane wave assump-
tion, this method can be applied to sound fields for which a model is not available.
Investigations were carried out by means of finite element simulations for a typical
case. The results show that the method is a promising method for determining the
effective area-averaged in situ sound absorption coefficient in complex sound fields
Studies on tableting properties of lactose. Part III. The consolidation behaviour of sieve fractions of crystalline a-lactose\ud monohydrate
The consolidation and compaction behaviour of sieve fractions of crystalline α-lactose monohydrate were studied. From mercury porosimetry measurements tablet pore surface areas were derived. At a certain compaction load it appeared that tablets compressed from small particles were generally stronger and showed a larger surface area than compacts prepared from coarse sieve fractions. By plotting compact strength against pore surface area, a unique linear relationship was obtained. From these results it can be concluded that the actual tablet surface area, being a function of both the initial particle size and applied compaction pressure, is responsible for the compact strength
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