Nonflammable organic-base paint for oxygen-rich atmospheres

New paint formulations, which combine aqueous latex paints with inorganic pigments and additives, produce coatings that are self-extinguishing in pure oxygen at pressures up to twice the partial pressure of atmospheric oxygen. A paint formulation in percent by weight is given and the properties of resultant coatings are discussed

Long-distance dispersal potential in a marine macrophyte

Plant populations have long been noted to migrate faster than predicted based on their life history and seed dispersal characteristics (i.e., Reid\u27s paradox of rapid plant migration). Although precise mechanisms to account for such phenomena are not fully known for all plant species, a combination of theoretical and empirically driven mechanisms often resolves this paradox. Here, we couple a series of direct and indirect field and laboratory exercises on one marine macrophyte, Zostera marina L. (eelgrass), to measured distances between new patches and established beds in order to elucidate the longdistance dispersal and colonization potential of this marine seagrass. Detached, floating reproductive shoots with mature seeds were found to remain positively buoyant for up to 2 wk and retain mature seeds for up to 3 wk before release under laboratory conditions. Analysis of the, detritus wrack along a remote shoreline found reproductive fragments with viable seeds up to 34 km from established, natural beds. Analysis of different regions of the Chesapeake Bay and coastal bays of the Delmarva Peninsula that once supported eelgrass populations, revealed natural patches at 13 sites ranging from 1 to 108 km from established populations. A combination of tidal currents and wind influences has the potential to move a passive particle at the surface (e.g., a floating reproductive fragment) up to 23 km in a 6-h tidal window suggesting that most unvegetated areas in this region that can support eelgrass are within the colonization potential envelope. We suggest that, when combined with earlier work on seed dispersal ecology of this species, eelgrass has strong qualities for high colonization potential of new habitat. The finding of natural patches at such great distances from established beds when studied in the context of the dispersal mechanism (currents and wind) make the dispersal distances of this species one of the highest for angiosperms, comparable in scale to mangroves and coconuts. This new understanding of the dispersal dynamics of eelgrass is critical in the context of seagrass restoration in areas distant from established beds, maintenance of existing populations threatened by anthropogenic inputs of sediments arid nutrients, and examining metapopulation concepts in seagrass ecology

Hybrid propulsion for launch vehicle boosters: A program status update

Results obtained in studying the origin and suppression of large-amplitude pressure oscillations in a 24 in. diameter hybrid motor using a liquid oxygen/hydroxylterminated polybutadiene/polycyclopentadiene propellant system are discussed. Tests conducted with liquid oxygen flow rates varying from 10 to 40 lbm/sec were designed to gauge the effectiveness of various vaporization chamber flow fields, injector designs, and levels of heat addition in suppressing high-frequency longitudinal mode oscillations. Longitudinal acoustic modes did not arise in any tests. However, initial testing revealed the presence of high-amplitude, sinusoidal, nonacoustic oscillations persisting throughout the burn durations. Analysis showed this to be analogous to chug mode instability in liquid rocket engines brought about by a coupling of motor combustion processes and the liquid oxygen feed system. Analytical models were developed and verified by test data to predict the amplitude and frequency of feed-system-coupled combustion pressure oscillations. Subsequent testing showed that increasing the feed system impedance eliminated the bulk mode instability. This paper documents the work completed to date in performance of the Hybrid Propulsion Technology for Launch Vehicle Boosters Program (NAS8-39942) sponsored by NASA's George C. Marshall Space Flight Center

A review of issues in seagrass seed dormancy and germination: implications for conservation and restoration

Seagrasses have received considerable attention over the past 2 decades because of the multiple ecological roles they play in estuarine and coastal ecosystems and concerns over worldwide losses of seagrass habitat due to direct and indirect human impacts. Restoration and conservation efforts are underway in some areas of the world, but progress may be limited by the paucity of information on the role of seeds in bed dynamics. Although flowering occurs in most of the 58 seagrass species, seed germination data exist for only 19 of the 42 species that have some period of dormancy, with only 93 published references to field and/or laboratory studies. This review addresses critical issues in conservation and restoration of seagrasses involving seed dormancy (e.g. environmental vs physiological), existence and type of seed bank (transient or persistent), and factors influencing seed germination (e.g, salinity, temperature, light). Results of many earlier published studies relating seed germination to various environmental factors may need re-examination given more recent published data which show a confounding influence of oxygen level on the germination process. We highlight the importance of conducting ecologically meaningful germination studies, including germination experiments conducted in sediments. We also identify questions for future research that may figure prominently in landscape level questions regarding protected marine or estuarine reserves, habitat fragmentation, and restoration

Experiencing parenthood, care and spaces of hospitality

Drawing on research conducted in Australia and the United Kingdom, this paper explores how parenting and care provision is entangled with, and thus produced through, consumption in hospitality venues. We examine how the socio-material practices of hospitality provision shape the enactment of parenting, alongside the way child-parent/consumer-provider interactions impact upon experiences of hospitality spaces. We argue that venues provide contexts for care provision, acting as spaces of sociality, informing children’s socialization and offering temporary relief from the work of parenting. However, the data also highlight various practices of exclusion and multiple forms of emotional and physical labour required from careproviders. The data illustrate children’s ability to exercise power and the ways in which parents’/carers’ experiences of hospitality spaces are shaped by their enactment of discourses of ‘good parenting’. Finally, we consider parents’/carers’ coping behaviours as they manage social and psychological risks associated with consumption in such public spaces of leisure

Analysis of a plasma test cell including non-neutrality and complex collision mechanisms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97097/1/AIAA2012-3736.pd

The likelihood of extinction of iconic and dominant herbivores and detritivores of coral reefs: the parrotfishes and surgeonfishes

Parrotfishes and surgeonfishes perform important functional roles in the dynamics of coral reef systems. This is a consequence of their varied feeding behaviors ranging from targeted consumption of living plant material (primarily surgeonfishes) to feeding on detrital aggregates that are either scraped from the reef surface or excavated from the deeper reef substratum (primarily parrotfishes). Increased fishing pressure and widespread habitat destruction have led to population declines for several species of these two groups. Species-specific data on global distribution, population status, life history characteristics, and major threats were compiled for each of the 179 known species of parrotfishes and surgeonfishes to determine the likelihood of extinction of each species under the Categories and Criteria of the IUCN Red List of Threatened Species. Due in part to the extensive distributions of most species and the life history traits exhibited in these two families, only three (1.7%) of the species are listed at an elevated risk of global extinction. The majority of the parrotfishes and surgeonfishes (86%) are listed as Least Concern, 10% are listed as Data Deficient and 1% are listed as Near Threatened. The risk of localized extinction, however, is higher in some areas, particularly in the Coral Triangle region. The relatively low proportion of species globally listed in threatened Categories is highly encouraging, and some conservation successes are attributed to concentrated conservation efforts. However, with the growing realization of man's profound impact on the planet, conservation actions such as improved marine reserve networks, more stringent fishing regulations, and continued monitoring of the population status at the species and community levels are imperative for the prevention of species loss in these groups of important and iconic coral reef fishes

The Conservation Status of Marine Biodiversity of the Pacific Islands of Oceania

The Pacific Islands of Oceania are small islands and atolls occurring over a vast expanse of ocean that are characterized by immense biodiversity and endemism. This project represents a major expansion of the coverage of the Pacific Islands’ marine biodiversity on the IUCN Red List of Threatened Species. The threats to Pacific Island marine biodiversity are many. Results from IUCN Red List initiatives such as this can guide decision-making and conservation prioritization of Pacific Island governments, non-governmental organizations (NGOs) and the private sector. By shaping regional and national policies with these data in mind, priority sites for maintaining marine biodiversity can be identified and conserved

Role of lattice distortion and A site cation in the phase transitions of methylammonium lead halide perovskites

The rapid increase in power conversion efficiencies of photovoltaic devices incorporating lead halide perovskites has resulted in intense interest in the cause of their excellent properties. In the present paper, resonant ultrasound spectroscopy has been used to determine the elastic and anelastic properties of CH3NH3PbX3 (where X=Cl, Br, or I) and CD3ND3PbI3 perovskites in the 5–380 K temperature range. This is coupled with differential scanning calorimetry, variable temperature neutron powder diffraction, and variable temperature photoluminescence studies to provide insights into the underlying processes and structural instabilities in the crystal structure. By comparing measurements on CH3NH3PbI3 with the deuterated equivalent, it has been possible to distinguish processes which are related to the hydrogen bonding between the methylammonium cation and the perovskite framework. We observe that replacing hydrogen with deuterium has a significant impact on both the elastic and photophysical properties, which shows that hydrogen bonding plays a crucial role in the material performance. Temperature-dependent photoluminescence studies show that the light emission is unaffected by the tetragonal-orthorhombic phase transition, but a blueshift in the emission and a steep increase in photoluminescence quantum yield are seen at temperatures below 150 K. Finally, observations of peaks in acoustic loss occurring in CH3NH3PbCl3 have revealed freezing processes in the vicinity of ∼150−170K, with activation energies in the range of 300 to 650 meV. These processes are attributed to freezing of the motion of methylammonium cations, and could explain the changes in photoluminescence seen in CH3NH3PbI3 at the same temperature

Seed production from the mixed mating system of Chesapeake Bay (USA) eelgrass (Zostera marina; Zosteraceae)

In monoecious plants, gametes can be exchanged in three ways: among unrelated genets (outbreeding), with close relatives (inbreeding), or within individuals (geitonogamous selling). These different mating systems may have consequences for population demography and fitness. The experiment presented herein used artificial crosses to examine the mating system of Chesapeake Bay, Virginia, USA eelgrass (Zostera marina L; Zosteraceae), a bisexual submerged aquatic plant that can outbreed, inbreed, and self. Genetic data indicate severe heterozygosity deficiencies and patchy genotype distribution in these beds, suggesting that plants therein reproduce primarily by vegetative propagation, autogamy, or geitonogamy. To clarify eelgrass reproductive strategies, flowers from three genetically and geographically distinct beds were hand-pollinated in outbred, inbred, and selfed matings. Fertilization success and seed production, life history stages which contribute greatly to the numeric maintenance of populations, were monitored. We found no evidence that inbreeding had negative consequences for seed production. On the contrary, selfed matings produced seeds significantly more frequently than outcrossed matings and produced significantly larger numbers of seeds than either inbred or outbred matings. These results contrast with patterns for eelgrass in other regions but might be expected for similar populations in which pollen limitation or a short reproductive season renders selfing advantageous