Civilizations and Sea Level Change

Climate and sea level changes have been relatively stable for the last few centuries. The delicate balance between global and oceanic systems, however, may be altered due to the increased warming of the earth's average surface temperature. A few degrees increase could cause a 15-17 cm sea level rise by the year 2000, resulting in wide spread flooding of low lying areas. Recent studies indicate the global sea level is rising and extensive coastal flooding is anticipated. If these changes continue through the next century, we may be faced with a loss of our present culture. Oscillating sea levels since the late Pleistocene at times have left the floors of the continental margins and inland seas exposed, increasing the total earth's land surface by 8%. It was during these events that North America and island refugia including England, Indonesia, Japan and Australia were invaded and colonized by man. However, the swinging sea levels and shoreline displacements of as much as 120 m per year must have been very disruptive to the inhabitants of the coastal region and evidence of their cultures must have eroded away due to the relentless cycle of the coastal processes.     

Space and ESDP—a growing partnership?

The ‘European satellites for security’ conference was held in Brussels, 18–19 June 2002, at a time when interest in the military use of outer space was clearly growing. But doubts remain as how to far such interest will be translated into action. This article reports on some of the impressions gained at the conference.     

"Living off the land": resource efficiency of wetland wastewater treatment.

Bioregenerative life support technologies for space application are advantageous if they can be constructed using locally available materials, and rely on renewable energy resources, lessening the need for launch and resupply of materials. These same characteristics are desirable in the global Earth environment because such technologies are more affordable by developing countries, and are more sustainable long-term since they utilize less non-renewable, imported resources. Subsurface flow wetlands (wastewater gardens(TM)) were developed and evaluated for wastewater recycling along the coast of Yucatan. Emergy evaluations, a measure of the environmental and human economic resource utilization, showed that compared to conventional sewage treatment, wetland wastewater treatment systems use far less imported and purchased materials. Wetland systems are also less energy-dependent, lessening dependence on electrical infrastructure, and require simpler maintenance since the system largely relies on the ecological action of microbes and plants for their efficacy. Detailed emergy evaluations showed that wetland systems use only about 15% the purchased emergy of conventional sewage systems, and that renewable resources contribute 60% of total emergy used (excluding the sewage itself) compared to less than 1% use of renewable resources in the high-tech systems. Applied on a larger scale for development in third world countries, wetland systems would require the electrical energy of conventional sewage treatment (package plants), and save of total capital and operating expenses over a 20-year timeframe. In addition, there are numerous secondary benefits from wetland systems including fiber/fodder/food from the wetland plants, creation of ecosystems of high biodiversity with animal habitat value, and aesthestic/landscape enhancement of the community. Wetland wastewater treatment is an exemplar of ecological engineering in that it creates an interface ecosystem to handle byproducts of the human economy, maximizing performance of the both the natural economy and natural ecosystems. Wetland systems accomplish this with far greater resource economy than other sewage treatment approaches, and thus offer benefits for both space and Earth applications.     

一种应用在航天探测器上的二氧化碳两相回路热控系统冷凝器的设计优化

阿尔法磁谱仪中的轨迹探测器是探测空间反物质的核心探测器,它工作于由超流液氦冷却的超导磁体的中心,其正常运作需要体积小、散热及温控能力强的热控系统的支持,以应对国际空间站上复杂的太空热流环境及真空、微重力等因素.介绍了利用SINDA/FLUINT模拟方法,对轨迹探测器的热控系统冷凝器进行设计优化.     

On the space trail

The future of the UK in space, and what could be done to support it, was the subject of Campaigning for Space, a conference organized by the Shephard Press and held in London, UK on 4 July 1988.     

A Comparison of Techniques for Solving the Poisson Equation in CFD

CFD is a ubiquitous technique central to much of computational simulation such as that required by aircraft design. Solving of the Poisson equation occurs frequently in CFD and there are a number of possible approaches one may leverage. The dynamical core of the MONC atmospheric model is one example of CFD which requires the solving of the Poisson equation to determine pressure terms. Traditionally this aspect of the model has been very time consuming and so it is important to consider how we might reduce the runtime cost. In this paper we survey the different approaches implemented in MONC to perform the pressure solve. Designed to take advantage of large scale, modern, HPC machines, we are concerned with the computation and communication behaviour of the available techniques and in this text we focus on direct FFT and indirect iterative methods. In addition to describing the implementation of these techniques we illustrate on up to 32768 processor cores of a Cray XC30 both the performance and scalability of our approaches. Raw runtime is not the only measure so we also make some comments around the stability and accuracy of solution. The result of this work are a number of techniques, optimised for large scale HPC systems, and an understanding of which is most appropriate in different situations.     

The Jupiter Energetic Particle Detector Instrument (JEDI) Investigation for the Juno Mission

The Jupiter Energetic Particle Detector Instruments (JEDI) on the Juno Jupiter polar-orbiting, atmosphere-skimming, mission to Jupiter will coordinate with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter’s polar regions, and specifically to understand the generation of Jupiter’s powerful aurora. JEDI comprises 3 nearly-identical instruments and measures at minimum the energy, angle, and ion composition distributions of ions with energies from H:20 keV and O: 50 keV to >1 MeV, and the energy and angle distribution of electrons from <40 to >500 keV. Each JEDI instrument uses microchannel plates (MCP) and thin foils to measure the times of flight (TOF) of incoming ions and the pulse height associated with the interaction of ions with the foils, and it uses solid state detectors (SSD’s) to measure the total energy (E) of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles. The instruments also use fast triple coincidence and optimum shielding to suppress penetrating background radiation and incoming UV foreground. Here we describe the science objectives of JEDI, the science and measurement requirements, the challenges that the JEDI team had in meeting these requirements, the design and operation of the JEDI instruments, their calibrated performances, the JEDI inflight and ground operations, and the initial measurements of the JEDI instruments in interplanetary space following the Juno launch on 5 August 2011. Juno will begin its prime science operations, comprising 32 orbits with dimensions 1.1×40 RJ, in mid-2016.     

Spatial fragmentation of solar flare plasma and beams

The observational and theoretical arguments for spatial fragmentation of the bulk of the thermal and non-thermal components of solar flare plasma are summarised. Observational aspects considered include XUV filling factors, EUV centre to limb variations, andH impact polarisation. Theoretical points addressed are the high flare inductance and beam/return current closure at the acceleration site.A high degree of beam/plasma filamentation implies strong transverse temperature gradients so that cross-field conduction must be included in energy transport modelling. Preliminary results are described for a simple two-component model.