16,355 research outputs found
High-efficiency device research
Progress on research in high-efficiency silicon solar cells is presented. Topics addressed include: recombination measurement techniques, doped crystals, minority carrier transport, oxygen process in solar cells, solar cell models, loss mechanics in solar cells, high-efficiency metal insulators, dendritic web cells, and surface and bulk loss reduction by low-energy hydrogen doping
Vacuum lamination of photovoltaic modules
Vacuum lamination of terrestrial photovoltaic modules is a new high volume process requiring new equipment and newly develop materials. Equipment development, materials research, and some research in related fields and testing methods are discussed
The FOMC in 1976: progress against inflation
Federal Open Market Committee ; Inflation (Finance)
FEM investigation of leaky modes in hollow core photonic crystal fibers
Hollow-core holey fibers are promising candidates for low-loss guidance of
light in various applications, e.g., for the use in laser guide star adaptive
optics systems in optical astronomy. We present an accurate and fast method for
the computation of light modes in arbitrarily shaped waveguides. Maxwell's
equations are discretized using vectorial finite elements (FEM). We discuss how
we utilize concepts like adaptive grid refinement, higher-order finite
elements, and transparent boundary conditions for the computation of leaky
modes in photonic crystal fibers. Further, we investigate the convergence
behavior of our methods. We employ our FEM solver to design hollow-core
photonic crystal fibers (HCPCF) whose cores are formed from 19 omitted cladding
unit cells. We optimize the fiber geometry for minimal attenuation using
multidimensional optimization taking into account radiation loss (leaky modes).Comment: 8 page
JCMmode: An Adaptive Finite Element Solver for the Computation of Leaky Modes
We present our simulation tool JCMmode for calculating propagating modes of
an optical waveguide. As ansatz functions we use higher order, vectorial
elements (Nedelec elements, edge elements). Further we construct transparent
boundary conditions to deal with leaky modes even for problems with
inhomogeneous exterior domains as for integrated hollow core Arrow waveguides.
We have implemented an error estimator which steers the adaptive mesh
refinement. This allows the precise computation of singularities near the
metal's corner of a Plasmon-Polariton waveguide even for irregular shaped metal
films on a standard personal computer.Comment: 11 page
Cooling Tower Considerations for Energy Optimizations
Energy conservation strategies and production
economies involve more than examining the
cooling tower fan consumption of horse power.
Colder water provides vast potentials for
savings. Ask yourself, "What is the dollar
and energy utilization value if I can obtain 1°F
colder water off my cooling tower than I am
now getting?" Therefore, let us first examine
the elements of the cooling tower to determine
the areas of greatest potential improvement to
generate that colder water.
The air flow generated by the fan should first
be looked at In both counterflow or crossflow
towers to determine that maximum flow is
available through pitching fans up to within
the motor plate amperage limitations and fan
stall point calculations. If applicable, new
fiberglass state of the art fans can be installed
and additional motor horse power added.
However, the most dramatic improvement that
can be obtained in producing colder water is
to retrofit modern film fill to replace the old
fashioned wood splash bar slats
Evolution of a coherent array of Bose-Einstein Condensates in a magnetic trap
We investigate the evolution process of the interference pattern for a
coherent array of Bose-Einstein condensates in a magnetic trap after the
optical lattices are switched off. It is shown that there is a decay and
revival of the density oscillation for the condensates confined in the magnetic
trap. We find that, due to the confinement of the magnetic trap, the
interference effect is much stronger than that of the experiment induced by
Pedri et al. (Phys. Rev. Lett, {\bf 87}, 220401), where the magnetic trap is
switched off too. The interaction correction to the interference effect is also
discussed for the density distribution of the central peak.Comment: RevTex, 17 pages,9 figures. E-mail: [email protected]
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