Power system technologies for the manned Mars mission

The high impulse of electric propulsion makes it an attractive option for manned interplanetary missions such as a manned mission to Mars. This option is, however, dependent on the availability of high energy sources for propulsive power in addition to that required for the manned interplanetary transit vehicle. Two power system technologies are presented: nuclear and solar. The ion thruster technology for the interplanetary transit vehicle is described for a typical mission. The power management and distribution system components required for such a mission must be further developed beyond today's technology status. High voltage-high current technology advancements must be achieved. These advancements are described. In addition, large amounts of waste heat must be rejected to the space environment by the thermal management system. Advanced concepts such as the liquid droplet radiator are discussed as possible candidates for the manned Mars mission. These thermal management technologies have great potential for significant weight reductions over the more conventional systems

Qualitative research toolkit: GAGE’s approach to researching with adolescents

This toolkit is a companion piece to the GAGE baseline qualitative research toolkit and provides the group and individual research tools, all of which are age-tailored (early adolescents, mid/older adolescents and adults), used during the second round of data collection in GAGE’s longitudinal study. A selection of these could be used to understand different dimensions of adolescent wellbeing and development trajectories in any given context. For the purposes of the GAGE research programme, this collection of tools has also been designed to mirror the GAGE ‘3 Cs’ conceptual framework which reflects the close connections between the ‘3 Cs’: capabilities, change strategies and contexts. It considers adolescents’ multidimensional capabilities and the ways in which these differ depending on age, gender and (dis)ability; the change strategies that are employed by families, communities, service providers, policy-makers, civil society and development partners to promote empowered and healthy transitions from adolescence into early adulthood; and finally the broader meso- and macro-level contexts that shape the enabling/constraining environments in which adolescent realities are played out (Figure 1). Adolescents are situated at the centre of this socio-ecological framework

Qualitative research toolkit to explore child marriage dynamics and how to fast-track prevention

Accelerating progress towards eliminating child marriage and empowering married girls requires not just more research, but different tools. Tools that are designed with action and inclusion in mind. GAGE’s new child marriage toolkit builds on existent tools, including those we used in our formative and baseline work (see GAGE baseline qualitative research tools), and hones in on how to prevent child marriage – for girls and boys – and mitigate its impacts on adolescent girls, including those who are separated and divorced. Our new tools focus on marriage decision-making and ask marriage decision-makers what might encourage them to make different decisions. They also trace the threats and opportunities that girls (and boys) face at various steps along the child marriage pathway (engagement to divorce) and explore how a range of services might improve outcomes. Most importantly, our new child marriage toolkit is built around the decision-making underpinning child marriage and the experiences of married adolescents, rather than indirectly through an exploration of adolescence more broadly. Our tools are directly aimed at two questions: how can we prevent child marriage and how can we make married girls’ (and boys’) lives better

Ecosystem-bedrock interaction changes nutrient compartmentalization during early oxidative weathering

Ecosystem-bedrock interactions power the biogeochemical cycles of Earth's shallow crust, supporting life, stimulating substrate transformation, and spurring evolutionary innovation. While oxidative processes have dominated half of terrestrial history, the relative contribution of the biosphere and its chemical fingerprints on Earth's developing regolith are still poorly constrained. Here, we report results from a two-year incipient weathering experiment. We found that the mass release and compartmentalization of major elements during weathering of granite, rhyolite, schist and basalt was rock-specific and regulated by ecosystem components. A tight interplay between physiological needs of different biota, mineral dissolution rates, and substrate nutrient availability resulted in intricate elemental distribution patterns. Biota accelerated CO2 mineralization over abiotic controls as ecosystem complexity increased, and significantly modified stoichiometry of mobilized elements. Microbial and fungal components inhibited element leaching (23.4% and 7%), while plants increased leaching and biomass retention by 63.4%. All biota left comparable biosignatures in the dissolved weathering products. Nevertheless, the magnitude and allocation of weathered fractions under abiotic and biotic treatments provide quantitative evidence for the role of major biosphere components in the evolution of upper continental crust, presenting critical information for large-scale biogeochemical models and for the search for stable in situ biosignatures beyond Earth.Comment: 41 pages (MS, SI and Data), 16 figures (MS and SI), 6 tables (SI and Data). Journal article manuscrip

Flux Density Variations at 3.6 cm in the Massive Star-Forming Region W49A

A number of ultracompact H II regions in Galactic star forming environments have been observed to vary significantly in radio flux density on timescales of 10-20 years. Theory predicted that such variations should occur when the accretion flow that feeds a young massive star becomes unstable and clumpy. We have targeted the massive star-forming region W49A with the Karl G. Jansky Very Large Array (VLA) for observations at 3.6 cm with the B-configuration at 0.8'' resolution, to compare to nearly identical observations taken almost 21 years earlier (February 2015 and August 1994). Most of the sources in the crowded field of ultracompact and hypercompact H II regions exhibit no significant changes over this time period. However, one source, W49A/G2, decreased by 20% in peak intensity (from 71+/-4 mJy/beam to 57+/-3 mJy/beam), and 40% in integrated flux (from 0.109+/-0.011 Jy to 0.067+/-0.007 Jy), where we cite 5 sigma errors in peak intensity, and 10% errors in integrated flux. We present the radio images of the W49A region at the two epochs, the difference image that indicates the location of the flux density decrease, and discuss explanations for the flux density decrease near the position of W49A/G2.Comment: 9 pages, 2 figures, accepted for publication, The Astrophysical Journal Letters, July 26, 201

Structure of bryozoan communities in an Antarctic glacial fjord (Admiralty Bay, South Shetlands)

Bryozoans are among the most important groups of the Southern Ocean benthic macrofauna, both in terms of species richness and abundance. However, there is a considerable lack of ecological research focused on their distribution patterns and species richness on smaller scale, especially in the soft bottom habitats of Antarctic glacial fjords. The aim of this study was to describe those patterns in the Admiralty Bay. Forty-nine Van Veen grab samples were collected at the depth range from 15 to 265 m, in the summer season of 1979/1980, at three sites distributed along the main axis of the fjord. Among 53 identified species of bryozoans, 32 were recorded in the Admiralty Bay for the first time. The most common and abundant species were Himantozoum antarcticum, Inversiula nutrix and Nematoflustra flagellata. Genera such as Arachnopusia, Cellarinella and Osthimosia were the most speciose taxa. It was demonstrated that depth was important for the distribution of the bryozoans. More than half of the recorded species were found only below 70 m. An influence of glacial disturbance was reflected in the dominance structure of colony growth-forms. The inner region of the fjord was dominated almost entirely by encrusting species, while the diversity of bryozoan growth-forms in less disturbed areas was much higher. In those sites the highest percentage of branched, tuft like species represented by buguliform and flustriform zoaria was observed.The study was supported by a grant of Polish Ministry of Science and Higher Education No. 51/N-IPY/2007/0 as well as Census of Antarctic Marine Life Project. Krzysztof Pabis was also partially supported by University of Lodz internal funds. This research was also supported by the Polish Geological Institute-National Research Institute during the realization of the project numbered 40.2900.0903.18.0 titled “Bryozoan assemblage of Admiralty Bay—richness, diversity and abundance.” Urszula Hara is deeply grateful to Leszek Giro (Micro-area Analyses Laboratory at the Polish Geological Institute-National Research Institute, Warsaw), for providing SEM assistance during the project. We also want to thank two anonymous reviewers for their suggestions that helped us improve this article. Thanks are also due to Magdalena Błażewicz-Paszkowycz for language correction and polishing the final version of the manuscript

Development of an Enhanced High-Yield Influenza Vaccine Backbone in Embryonated Chicken Eggs

Vaccination is an efficient approach to preventing influenza virus infections. Recently, we developed influenza A and B virus vaccine backbones that increased the yield of several vaccine viruses in Madin–Darby canine kidney (MDCK) and African green monkey kidney (Vero) cells. These vaccine backbones also increased viral replication in embryonated chicken eggs, which are the most frequently used platform for influenza vaccine manufacturing. In this study, to further increase the viral titers in embryonated chicken eggs, we introduced random mutations into the ‘internal genes’ (i.e., all influenza viral genes except those encoding the hemagglutinin and neuraminidase proteins) of the influenza A virus high-yield virus backbone we developed previously. The randomly mutated viruses were sequentially passaged in embryonated chicken eggs to select variants with increased replicative ability. We identified a candidate that conferred higher influenza virus growth than the high-yield parental virus backbone. Although the observed increases in virus growth may be considered small, they are highly relevant for vaccine manufacturers

NOVEL TECHNOLOGIES FOR GASEOUS CONTAMINANTS CONTROL

Overall objective of this project was to develop a technology platform for cleaning/conditioning the syngas from an integrated gasification combined cycle (IGCC) system at elevated temperatures (500-1,000 F) and gasifier pressures to meet the tolerance limits for contaminants, including H{sub 2}S, COS, NH{sub 3}, HCl, Hg, and As. This technology development effort involved progressive development and testing of sorbent/catalytic materials and associated processes through laboratory, bench, pilot, and demonstration testing phases, coupled with a comprehensive systems analysis at various stages of development. The development of the regenerable RTI-3 desulfurization sorbent - a highly attrition-resistant, supported ZnO-based material - was the key discovery in this project. RTI-3's high attrition resistance, coupled with its high reactivity, effectively allowed its application in a high-velocity transport reactor system. Production of the RTI-3 sorbent was successfully scaled up to an 8,000-lb batch by Sued-Chemie. In October 2005, RTI obtained U.S Patent 6,951,635 to protect the RTI-3 sorbent technology and won the 2004 R&D 100 Award for development of this material. The RTI-3 sorbent formed the basis for the development of the High-Temperature Desulfurization System (HTDS), a dual-loop transport reactor system for removing the reduced sulfur species from syngas. An 83-foot-tall, pilot HTDS unit was constructed and commissioned first at ChevronTexaco's gasification site and later at Eastman's gasification plant. At Eastman, the HTDS technology was successfully operated with coal-derived syngas for a total of 3,017 hrs over a 12-month period and consistently reduced the sulfur level to <10 ppmv. The sorbent attrition rate averaged {approx}31 lb/MM lb of circulation. To complement the HTDS technology, which extracts the sulfur from syngas as SO{sub 2}, RTI developed the Direct Sulfur Recovery Process (DSRP). The DSRP, operating at high pressure and high temperature, uses a small slipstream of syngas to catalytically reduce the SO{sub 2} produced in the warm syngas desulfurization process to elemental sulfur. To demonstrate this process at Eastman, RTI constructed and commissioned a skid-mounted pilot DSRP unit. During its 117-h operation, the DSRP system achieved 90% to 98% removal of the inlet sulfur. The DSRP catalyst proved very robust, demonstrating consistent reaction rates in multiple experiments over a 3-year period. Sorbent materials for removing trace NH{sub 3}, Hg, and As impurities from syngas at high temperature and high pressure were developed and tested with real syngas. A Li{sub 4}SiO{sub 4} sorbent for removal of CO{sub 2} from syngas at high temperature was also developed and tested. The Li{sub 4}SiO{sub 4} material demonstrates excellent CO{sub 2} removal, but its regeneration was found to be technically challenging. Additionally, reverse-selective polymer membrane materials were investigated for the bulk removal of CO{sub 2} and H{sub 2}S from syngas. These materials exhibited adequate separation at ambient conditions for these acid gases. Field testing of these membrane modules with real syngas demonstrated potential use for acid-gas separation from syngas. The HTDS/DSRP technologies are estimated to have a significant economic advantage over conventional gas cleanup technologies such as Selexol{trademark} and Rectisol. From a number of system studies, use of HTDS/DSRP is expected to give a 2-3 percentage point increase in the overall IGCC thermal efficiency and a significant reduction in capital cost. Thus, there is significant economic incentive for adaptation of these warm gas cleanup technologies due to significantly increased thermal efficiency and reduction in capital and operating costs. RTI and Eastman are currently in discussions with a number of companies to commercialize this technology