Briefing:Concrete – Innovations and practical applications

Concrete is a highly adaptable material and capable of considerable variation, development and innovation, as can be seen from the pages of journals such as the Proceedings of the Institution of Civil Engineers–Construction Materials. This briefing paper describes the 43rd Convention of the Institute of Concrete Technology, which took place on 26 March 2015. The event provided an opportunity for practitioners and researchers to meet and communicate, and to showcase the variety and diversity of current innovations, developments and applications in concrete and cement technology, including carbon-negative aggregate, polycarboxylate ether superplasticisers, waste wood in concrete, steel fibres, calcium aluminate cements, superabsorbent polymers and sprayed concrete tunnel linings

Spacecraft Charging Issues for Launch Vehicles

Spacecraft charging is well known threat to successful long term spacecraft operations and instrument reliability in orbits that spend significant time in hot electron environments. In recent years, spacecraft charging has increasingly been recognized as a potentially significant engineering issue for launch vehicles used to deploy spacecraft using (a) low Earth orbit (LEO), high inclination flight trajectories that pass through the auroral zone, (b) geostationary transfer orbits that require exposures to the hot electron environments in the Earths outer radiation belts, and (c) LEO escape trajectories using multiple phasing orbits through the Earths radiation belts while raising apogee towards a final Earth escape geometry. Charging becomes an issue when significant areas of exposed insulating materials or ungrounded conductors are used in the launch vehicle design or the payload is designed for use in a benign charging region beyond the Earths magnetosphere but must survive passage through the strong charging regimes of the Earths radiation belts. This presentation will first outline the charging risks encountered on typical launch trajectories used to deploy spacecraft into Earth orbit and Earth escape trajectories. We then describe the process used by NASAs Launch Services Program to evaluate when surface and internal charging is a potential risk to a NASA mission. Finally, we describe the options for mitigating charging risks including modification of the launch vehicle and/or payload design and controlling the risk through operational launch constraints to avoid significant charging environment

A comparative encyclopedia of DNA elements in the mouse genome

The laboratory mouse shares the majority of its protein-coding genes with humans, making it the premier model organism in biomedical research, yet the two mammals differ in significant ways. To gain greater insights into both shared and species-specific transcriptional and cellular regulatory programs in the mouse, the Mouse ENCODE Consortium has mapped transcription, DNase I hypersensitivity, transcription factor binding, chromatin modifications and replication domains throughout the mouse genome in diverse cell and tissue types. By comparing with the human genome, we not only confirm substantial conservation in the newly annotated potential functional sequences, but also find a large degree of divergence of sequences involved in transcriptional regulation, chromatin state and higher order chromatin organization. Our results illuminate the wide range of evolutionary forces acting on genes and their regulatory regions, and provide a general resource for research into mammalian biology and mechanisms of human diseases

Suicide ideation of individuals in online social networks

Suicide explains the largest number of death tolls among Japanese adolescents in their twenties and thirties. Suicide is also a major cause of death for adolescents in many other countries. Although social isolation has been implicated to influence the tendency to suicidal behavior, the impact of social isolation on suicide in the context of explicit social networks of individuals is scarcely explored. To address this question, we examined a large data set obtained from a social networking service dominant in Japan. The social network is composed of a set of friendship ties between pairs of users created by mutual endorsement. We carried out the logistic regression to identify users' characteristics, both related and unrelated to social networks, which contribute to suicide ideation. We defined suicide ideation of a user as the membership to at least one active user-defined community related to suicide. We found that the number of communities to which a user belongs to, the intransitivity (i.e., paucity of triangles including the user), and the fraction of suicidal neighbors in the social network, contributed the most to suicide ideation in this order. Other characteristics including the age and gender contributed little to suicide ideation. We also found qualitatively the same results for depressive symptoms.Comment: 4 figures, 9 table

Opposing effects of agricultural intensification on two ecologically similar species

Brown hares and rabbits are widely distributed in agricultural landscapes across the UK, occupy similar habitats and have considerable dietary overlap. However, as agriculture in the UK has intensified, hares have declined and become a species of conservation concern while rabbits have become an increasing pest. An intensive study of hares, rabbits and the dynamics of pastures over two grazing seasons was undertaken, in order to understand the environmental factors associated with hare and rabbit abundance at field level. Linear mixed models were used to assess the environmental variables, in terms of the structure, nutritional components and effects of livestock grazing that are associated with the abundance of the two species. The models revealed that hares were negatively associated with grazing intensity and plant diversity, whereas rabbits showed the strongest associations with nutritional content of pastures, in particular fat, nitrogen and fibre content in forage, as well as a positive association with short grass swards. The data suggest that, at the field-scale intensification of pasture use may have contributed to declines in hares and increases in rabbits

Mathematical modeling and design of layer crystallization in a concentric annulus with and without recirculation

A solution layer crystallization process in a concentric annulus is presented that removes the need for filtration. A dynamic model for layer crystallization with and without a recirculation loop is developed in the form of coupled partial differential equations describing the effects of mass transfer, heat transfer, and crystallization kinetics. The model predicts the variation of the temperature, concentration, and dynamic crystal thickness along the pipe length, and the concentration and temperature along the pipe radius. The model predictions are shown to closely track experimental data that were not used in the model's construction, and also compared to an analytical solution that can be used for quickly obtaining rough estimates when there is no recirculation loop. The model can be used to optimize product yield and crystal layer thickness uniformity, with constraints on the supersaturation to avoid bulk nucleation by adjusting cooling temperatures in the core and jacket. © 2013 American Institute of Chemical Engineers

Mathematical modeling and design of layer crystallization in a concentric annulus with and without recirculation [Abstract]

Mathematical modeling and design of layer crystallization in a concentric annulus with and without recirculation [Abstract