Mercury orbiter transport study

A data base and comparative performance analyses of alternative flight mode options for delivering a range of payload masses to Mercury orbit are provided. Launch opportunities over the period 1980-2000 are considered. Extensive data trades are developed for the ballistic flight mode option utilizing one or more swingbys of Venus. Advanced transport options studied include solar electric propulsion and solar sailing. Results show the significant performance tradeoffs among such key parameters as trip time, payload mass, propulsion system mass, orbit size, launch year sensitivity and relative cost-effectiveness. Handbook-type presentation formats, particularly in the case of ballistic mode data, provide planetary program planners with an easily used source of reference information essential in the preliminary steps of mission selection and planning

The synthesis of boron carbide filaments final report

Synthesis, strength, crystal structure, and composite material formation of boron carbide whisker

Sex, Drugs and the IMF: Some Implications of "Structural Readjustmentn for the Bade in Heroin, Girls and Women in the Upper Mekong Region

A highly informed and detailed analysis of the intimate relationship between structural adjustment programs and the thriving drug and sex trade in the Upper Mekong Region of Thailand, providing additional perspective on illicit traficking and trade in the larger Southeast Asian context. Attention is specifically drawn to the harsh and disproportional impact of IMF economic policies upon women and girls, also acknowledging the great importance of and understanding of international traffic in persons, in terms of migration problems and labour exploitation, rather than solely in relation to sex.Une analyse très fouillée de la relation intime qui s'établit entre les programmes d'ajustement structuraux et le florissant commerce de la drogue et des faveurs sexuelles. dans la région du Haut Mékong en Thaïlande; ce commerce ayant comme principale caractéristique de fournir un aperçu complémentaire sur toutes les formes de trafics illicite dans le contexte plus large de l'Asie du Sud-Est. Le caractère cru et disproportionné de l'impact des politiques économiques du F.M.I. sur la vie des femmes et des jeunes filles de la région est examiné avec une attention particulière. Il est aussi tenu compte de l'importance que revêt une compréhension plus large de la traite des blanches, nommément de par la description de la situation en termes de problèmes migratoires et d'exploitation de la force de travail, plutôt que strictement en termes de questions de nature sexuelle

Study of the growth parameters involved in synthesizing boron carbide filaments Second quarterly report

Growth parameters in synthesis of boron carbide whisker

Deformations and dilations of chaotic billiards, dissipation rate, and quasi-orthogonality of the boundary wavefunctions

We consider chaotic billiards in d dimensions, and study the matrix elements M_{nm} corresponding to general deformations of the boundary. We analyze the dependence of |M_{nm}|^2 on \omega = (E_n-E_m)/\hbar using semiclassical considerations. This relates to an estimate of the energy dissipation rate when the deformation is periodic at frequency \omega. We show that for dilations and translations of the boundary, |M_{nm}|^2 vanishes like \omega^4 as \omega -> 0, for rotations like \omega^2, whereas for generic deformations it goes to a constant. Such special cases lead to quasi-orthogonality of the eigenstates on the boundary.Comment: 4 pages, 3 figure

Investigation of the reinforcement of ductile metals with strong, high modulus discontinuous brittle fibers Quarterly report

Factors affecting reinforcement of aluminum with boron carbide whisker

An assessment of aerosol‐cloud interactions in marine stratus clouds based on surface remote sensing

An assessment of aerosol-cloud interactions (ACI) from ground-based remote sensing under coastal stratiform clouds is presented. The assessment utilizes a long-term, high temporal resolution data set from the Atmospheric Radiation Measurement (ARM) Program deployment at Pt. Reyes, California, United States, in 2005 to provide statistically robust measures of ACI and to characterize the variability of the measures based on variability in environmental conditions and observational approaches. The average ACIN (= dlnNd/dlna, the change in cloud drop number concentration with aerosol concentration) is 0.48, within a physically plausible range of 0–1.0. Values vary between 0.18 and 0.69 with dependence on (1) the assumption of constant cloud liquid water path (LWP), (2) the relative value of cloud LWP, (3) methods for retrieving Nd, (4) aerosol size distribution, (5) updraft velocity, and (6) the scale and resolution of observations. The sensitivity of the local, diurnally averaged radiative forcing to this variability in ACIN values, assuming an aerosol perturbation of 500 c-3 relative to a background concentration of 100 cm-3, ranges betwee-4 and -9 W -2. Further characterization of ACI and its variability is required to reduce uncertainties in global radiative forcing estimates

On fundamental domains and volumes of hyperbolic Coxeter-Weyl groups

We present a simple method for determining the shape of fundamental domains of generalized modular groups related to Weyl groups of hyperbolic Kac-Moody algebras. These domains are given as subsets of certain generalized upper half planes, on which the Weyl groups act via generalized modular transformations. Our construction only requires the Cartan matrix of the underlying finite-dimensional Lie algebra and the associated Coxeter labels as input information. We present a simple formula for determining the volume of these fundamental domains. This allows us to re-produce in a simple manner the known values for these volumes previously obtained by other methods.Comment: v2: to be published in Lett Math Phys (reference added, typo corrected