57,969 research outputs found
Laser ignition of an optically sensitised secondary explosive by a diode laser
As a green technology, laser ignition of a relatively insensitive secondary
explosive has been experimentally investigated. The explosive, hexanitrostilbene
(HNS), was doped with one of two optical sensitizers, carbon black or a laser
absorbing dye, and a continuous-wave (CW) infrared diode laser was used as the
igniting source. The ignition sensitivities of HNS with each of the two optical
sensitizers were analysed and compared in terms of: optical power threshold for
ignition, ignition delay and full burn delay at various laser powers. The results
have shown that both the chemical dye and carbon black optically sensitize
the explosive with similar efficiencies. In contrast to the carbon black, the dye
provides wavelength specificity and selectivity in the laser ignition process and its
solubility in some specific solvents improves the coating of the explosive material.
It was therefore concluded that the laser absorbing dye is a better candidate for
optical sensitization in laser ignition than the commonly used carbon black. The
combination of laser ignition sensitivity with wavelength selectivity potentially
offers higher reliability and safety at a low optical power for future ignitors of
secondary explosives
Groupoid normalisers of tensor products: infinite von Neumann algebras
The groupoid normalisers of a unital inclusion of von Neumann
algebras consist of the set of partial isometries
with and . Given two unital inclusions
of von Neumann algebras, we examine groupoid normalisers for
the tensor product inclusion $B_1\ \overline{\otimes}\ B_2\subseteq M_1\
\overline{\otimes}\ M_2$
\mathcal{GN}_{M_1\,\overline{\otimes}\,M_2}(B_1\ \overline{\otimes}\
B_2)''=\mathcal{GN}_{M_1}(B_1)''\ \overline{\otimes}\ \mathcal{GN}_{M_2}(B_2)''
when one inclusion has a discrete relative commutant equal to
the centre of (no assumption is made on the second inclusion). This
result also holds when one inclusion is a generator masa in a free group
factor. We also examine when a unitary
normalising a tensor product of irreducible
subfactors factorises as (for some unitary $w\in B_1\
\overline{\otimes}\ B_2v_i\in\mathcal{N}_{M_i}(B_i)M_iB_i_1B_1M_1, B_2M_2$) as
those with a trivial fundamental group.Comment: 22 page
A theoretical analysis of the current-voltage characteristics of solar cells
The correlation of theoretical and experimental data is discussed along with the development of a complete solar cell analysis. The dark current-voltage characteristics, and the parameters for solar cells are analyzed. The series resistance, and impurity gradient effects on solar cells were studied, the effects of nonuniformities on solar cell performance were analyzed
A theoretical analysis of the current-voltage characteristics of solar cells
The following topics are discussed: (1) dark current-voltage characteristics of solar cells; (2) high efficiency silicon solar cells; (3) short circuit current density as a function of temperature and the radiation intensity; (4) Keldysh-Franz effects and silicon solar cells; (5) thin silicon solar cells; (6) optimum solar cell designs for concentrated sunlight; (7) nonuniform illumination effects of a solar cell; and (8) high-low junction emitter solar cells
Ecoenzymes as Indicators of Compost to Suppress Rhizoctonia solani
Reports of disease suppression by compost are inconsistent likely because there are no established standards for feedstock material, maturity age for application, and application rate. The overall goal of the study was to evaluate a suite of biological indicators for their ability to predict disease suppression. Indicators included both commercial available methods for compost stability (Solvitaâ„¢, respiration) and metrics of soil ecology not yet adopted by the compost industry (e.g., ecoenzymes, nematode community index). Damping-off by Rhizoctonia solani on radish was chosen as a model system given its global importance, competitiveness affected by carbon quality, and lack of disease management options for organic production. Biological indicators were evaluated for their ability to consistently differentiate among curing process, maturity, and feedstock material as a function of disease severity of a seedling bioassay and a compost extract assay to test competition with R. solani growth. Compost processed as vermicompost and anaerobic digestate were more suppressive against R. solani than windrow or aerated static pile. Mature composts were more suppressive than immature components. Feedstocks containing dairy manure and/or hardwood bark tended to have suppressive qualities. In contrast, poultry manure-based components were conducive to disease. Microbial ecoenzymes active on chitin and cellulose and nematode community indices were better predictors of disease suppressiveness than microbial respiration. These indicators are quicker than plant bioassays and could be adopted as tools to certify commercial products
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