Solar thermal energy receiver

A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity

An introduction to ghost imaging: quantum and classical

Ghost imaging has been a subject of interest to the quantum optics community for the past 20 years. Initially seen as manifestation of quantum spookiness, it is now recognized as being implementable in both single- and many-photon number regimes. Beyond its scientific curiosity, it is now feeding novel imaging modalities potentially offering performance attributes that traditional approaches cannot match

The Housing Wealth Effect: The Crucial Roles of Demographics, Wealth Distribution and Wealth Shares

Current estimates of housing wealth effects vary widely. We consider the role of omitted variables suggested by economic theory that have been absent in a number of prior studies. Our estimates take into account age composition and wealth distribution (using poverty rates as a proxy), as well as wealth shares (how much of total wealth is comprised of housing vs. stock wealth). We exploit cross-state variation in housing, stock wealth and other variables in a newly assembled panel data set and find that the impact of housing on consumer spending depends crucially on age composition, poverty rates, and the housing wealth share. In particular, young people who are more likely to be credit-constrained, and older homeowners, likely to be “trading down” on their housing stock, experience the largest housing wealth effects, as suggested by theory. Also, as suggested by theory, housing wealth effects are higher in state-years with higher housing wealth shares, and in state-years with higher poverty rates (likely reflecting the greater importance of credit constraints for those observations). Taking these various factors into account implies huge variation over time and across states in the size of housing wealth effects.

DichroMatch: a website for similarity searching of circular dichroism spectra

Circular dichroism (CD) spectroscopy is a widely used method for examining the structure, folding and conformational changes of proteins. A new online CD analysis server (DichroMatch) has been developed for identifying proteins with similar spectral characteristics by detecting possible structurally and functionally related proteins and homologues. DichroMatch includes six different methods for determining the spectral nearest neighbours to a query protein spectrum and provides metrics of how similar these spectra are and, if corresponding crystal structures are available for the closest matched proteins, information on their secondary structures and fold classifications. By default, DichroMatch uses all the entries in the Protein Circular Dichroism Data Bank (PCDDB) for its comparison set, providing the broadest range of publicly available protein spectra to match with the unknown protein. Alternatively, users can download or create their own specialized data sets, thereby enabling comparisons between the structures of related proteins such as wild-type versus mutants or homologues or a series of spectra of the same protein under different conditions. The DichroMatch server is freely available at http://dichromatch.cryst.bbk.ac.uk

Noise produced by a small-scale, externally blown flap

Noise data were obtained with a model of an externally blown flap of the type that is currently being considered for STOL aircraft. The noise caused by impingement of the jet on the flap is much louder than the nozzle jet noise. It is especially so directly below the wing. The noise level increases as the jet velocity and flap angle are increased. The sound power level increased with the sixth power of velocity. Several physical variations to the STOL model configuration were also tested. Two such variations, a large board and a slotless curved plate wing, had the same power spectra density (Strouhal number curve) as the model

Experimental Study of Parametric Autoresonance in Faraday Waves

The excitation of large amplitude nonlinear waves is achieved via parametric autoresonance of Faraday waves. We experimentally demonstrate that phase locking to low amplitude driving can generate persistent high-amplitude growth of nonlinear waves in a dissipative system. The experiments presented are in excellent agreement with theory.Comment: 4 pages, 4 eps figures, to appear in Phys. Rev. Let

Photocatalytic generation of hydrogen from water

A concept designed to overcome the problems encountered when using photodissociation for the generation of hydrogen is discussed. The problems limiting the efficiency of photodissociation of water are the separation of the photolysis products and the high energy photons necessary for the reaction. It is shown that the dissociation energy of a large number of molecules is catalytically reduced when these molecules are in intimate contact with the surface of certain metals. It is proposed to develop a surface which will take advantage of this catalytic shift in dissociation energies to reduce the photon energy required to produce hydrogen. This same catalytic surface can be used to separate the reaction products if it is made so that one of the dissociations products is soluble in the metal and others are not. This condition is met by many metal systems such as platinum group metals which have been used commercially to separate hydrogen from other gases and liquids

A Whole-Class Support Model for Early Literacy: The Anna Plan

The Anna Plan is a unique delivery model for enhancing schoolwide literacy instruction in the primary grades. Based on the principles of Reading Recovery and Four Blocks literacy instruction, it provides supplementary reading instruction through the distinctive use of teaching staff. Over six years, it has resulted in sweeping changes in the way literacy instruction occurs as well as noteworthy increases in children\u27s reading abilities. This article gives a brief history of the authors\u27 work within the Anna Plan, explains each of the model\u27s seven tenets, and describes the research base that drives it. The focal point of the article is the detailed description of the organization and components of the five-day framework used to augment classroom reading and writing instruction. Finally, the authors recount how the Anna Plan has been embraced by two elementary schools and offer some conclusions about what contributes to the success of whole-class support models for early literacy