Pioneer 11's encounter with Jupiter and mission to Saturn

Plans for Pioneer 11's approach to Saturn are described. A flyby somewhat parallel to the ring plane is being proposed as an interim target, with a future option held for a possible high risk (or suicide) plunge through the nearly transparent space between Saturn and its rings

Energy versus electron transfer in organic solar cells: a comparison of the photophysics of two indenofluorene: fullerene blend films

In this paper, we compare the photophysics and photovoltaic device performance of two indenofluorene based polymers: poly[2,8-(6,6,12,12-tetraoctylindenofluorene)-co-4,7-(2,1,3-benzothiodiazole] (IF8BT) and poly[2,8-(6,6,12,12-tetraoctylindenofluorene)-co-5,5-(40,70-di-2-thienyl-20,10,30-benzothiodiazole] (IF8TBTT) blended with [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Photovoltaic devices made with IF8TBTT exhibit greatly superior photocurrent generation and photovoltaic efficiency compared to those made with IF8BT. The poor device efficiency of IF8BT/PCBM devices is shown to result from efficient, ultrafast singlet F€orster energy transfer from IF8BT to PCBM, with the resultant PCBM singlet exciton lacking sufficient energy to drive charge photogeneration. The higher photocurrent generation observed for IF8TBTT/PCBM devices is shown to result from IF8TBTT’s relatively weak, red-shifted photoluminescence characteristics, which switches off the polymer to fullerene singlet energy transfer pathway. As a consequence, IF8TBTT singlet excitons are able to drive charge separation at the polymer/fullerene interface, resulting in efficient photocurrent generation. These results are discussed in terms of the impact of donor/acceptor energy transfer upon photophysics and energetics of charge photogeneration in organic photovoltaic\ud devices. The relevance of these results to the design of polymers for organic photovoltaic applications is also discussed, particularly with regard to explaining why highly luminescent polymers developed for organic light emitting diode applications often give relatively poor performance in organic photovoltaic devices

Ablation debris control by means of closed thick film filtered water immersion

The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types

Optimization of the neutron yield in fusion plasmas produced by Coulomb explosions of deuterium clusters irradiated by a petawatt laser

The kinetic energy of hot (multi-keV) ions from the laser-driven Coulomb explosion of deuterium clusters and the resulting fusion yield in plasmas formed from these exploding clusters has been investigated under a variety of conditions using the Texas Petawatt laser. An optimum laser intensity was found for producing neutrons in these cluster fusion plasmas with corresponding average ion energies of 14 keV. The substantial volume (1-10 mm(3)) of the laser-cluster interaction produced by the petawatt peak power laser pulse led to a fusion yield of 1.6x10(7) neutrons in a single shot with a 120 J, 170 fs laser pulse. Possible effects of prepulses are discussed. DOI: 10.1103/PhysRevE.87.023106Glenn Focht Memorial FellowshipNNSA DE-FC52-08NA28512DOE Office of Basic Energy SciencesPhysic

Parejas de Hecho: una Estructura Familiar Olvidada que Cobra Importancia en el Ámbito de la Empresa Familiar

Cohabiting couples are a rapidly growing family form in the world today.  However, this family form has not been accounted for in family business research.  In this article, we examine the differences between cohabiting couples and married couples in terms of human capital, social capital, and financial capital.  Moreover, we explore how these differences may impact outcomes for firms owned by cohabiting and married couples.  Finally, we discuss how family business scholars can account for cohabiting couples in their research and how such research may help practitioners.Las parejas de hecho son una estructura familiar que está creciendo rápidamente en el mundo actual. Sin embargo, esta forma familiar no se ha tenido en cuenta en las investigaciones de empresa familiar. En este artículo examinamos las diferencias entre parejas que cohabitan y parejas casadas en términos de capital humano, capital social y capital financiero. Además, exploramos cómo estas diferencias pueden afectar a los resultados de las empresas propiedad de parejas casadas y parejas de hecho. Finalmente, discutimos la necesidad de considerar a las parejas de hecho como una estructura familiar en las investigaciones sobre empresa familiar, ya que pueden ayudar a comprender mejor las singularidades de estas empresas

Two-divisibility of the coefficients of certain weakly holomorphic modular forms

We study a canonical basis for spaces of weakly holomorphic modular forms of weights 12, 16, 18, 20, 22, and 26 on the full modular group. We prove a relation between the Fourier coefficients of modular forms in this canonical basis and a generalized Ramanujan tau-function, and use this to prove that these Fourier coefficients are often highly divisible by 2.Comment: Corrected typos. To appear in the Ramanujan Journa

Effectiveness of Automatic Fire Sprinklers in High Ceiling Areas & the Impact of Sprinkler Skipping

There is a misconception that sprinklers will offer little value in non-storage areas with high ceiling heights such as seating areas in theatres, atria in high rise buildings, auditoriums, sports arenas, school and university gymnasiums, meeting rooms in convention centres and hotels, exhibition halls, movie and television studios, casinos, concert halls and the back of stage of theatres or auditoriums. This project examines the misconception that sprinklers offer little value in non-storage areas with high ceilings, with the goal of determining whether sprinklers are effective in these areas. This project also examines the issue of sprinkler skipping, which fire testing has shown to be more pronounced for areas with higher ceiling clearances and the effect that sprinkler skipping has on the effectiveness of sprinklers in areas with high ceiling clearances

An electron-stimulated desorption ion angular distribution and low-energy electron diffraction investigation of CF3I on Ru(001)

We have investigated the structures of CF3I, and its dissociation products, adsorbed on Ru(001) using low-energy electron diffraction and electron-stimulated desorption ion angular distribution (ESDIAD). Atomic iodine forms (√3x√3)R30° islands even at very low coverages. At 70% of saturation and above, a (2X2) superstructure forms which we attribute to a p(2X2) unit cell with one CF3 group and one iodine atom. ESDIAD images show F+ desorbing at normal emission and in three hexagonal patterns. The normal emission is attributed to a tilted configuration of CF3(ad) in which one C-F bond is oriented perpendicular to the surface. A small hexagon is attributed to F(ad) on step edges. A large hexagon at low coverages may arise from isolated CF3(ad) species possessing C3v symmetry. And finally, an intermediate hexagon is attributed to perturbation of the CF3(ad) orientation by molecular fragments which result from electron irradiation of physisorbed CF3I