Electromagnetic Launch to Space

Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults and missile launchers. Such technology could serve as the basis for the launch of a first-stage booster launch -for example, as suggested some years ago by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. For higher velocities, experimental laboratory railguns have demonstrated launch velocities of 2-3 km/s and muzzle energies greater than 10 MJ. The extension of this technology to the muzzle velocities (≥ 7500 m/s) and energies (hundreds of megajoules) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and material. This paper provides an overview of these concepts and includes a summary of the recent advances made in this area. PACS numbers: 96.12. Hg, 98.35.Eg, 94.30.Kq, 94.05.Rx, 94.20.Fg, 94.20.wc, 94.20.w

Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Transportation of the MOAB Uranium Mill Tailings to White Mesa Mill by Slurry Pipeline

The Moab uranium mill tailings pile, located at the former Atlas Minerals Corporation site approximately three miles north of Moab, Utah, is now under the control of the US Department of Energy (''DOE''). The location of the tailings pile adjacent to the Colorado River, and the ongoing contamination of groundwater and seepage of pollutants into the river, have lead to the investigation, as part of the final site remediation program, of alternatives to relocate the tailings to a qualified permanent disposal site. This paper will describe the approach being taken by the team formed between International Uranium (USA) Corporation (''IUC'') and Washington Group International (''WGINT'') to develop an innovative technical proposal to relocate the Moab tailings to IUC's White Mesa Mill south of Blanding, Utah. The proposed approach for relocating the tailings involves using a slurry pipeline to transport the tailings to the White Mesa Mill. The White Mesa Mill is a fully licensed, active uranium mill site that is uniquely suited for permanent disposal of the Moab tailings. The tailings slurry would be dewatered at the White Mesa Mill, the slurry water would be recycled to the Moab site for reuse in slurry makeup, and the ''dry'' tailings would be permanently disposed of in an approved below grade cell at the mill site

Electromagnetic Launch to Space

Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults and missile launchers. Such technology could serve as the basis for the launch of a first-stage booster launch - for example, as suggested some years ago by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. For higher velocities, experimental laboratory railguns have demonstrated launch velocities of 2-3 km/s and muzzle energies greater than 10 MJ. The extension of this technology to the muzzle velocities ( ≥ 7500 m/s) and energies (hundreds of megajoules) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and material. This paper provides an overview of these concepts and includes a summary of the recent advances made in this area

Synthesis and magnetic properties of Co nanorod superlattices

We present the synthesis and magnetic properties of Co nanorods spontaneously organized in superlattices over a surface of several microns. This material results from the decomposition of a cobalt coordination precursor under hydrogen, in the presence of a long-chain amine and a long-chain acid. This synthetic procedure permits a remarkable control over the size distribution of the nanorods (diameter of 5 unit and controllable mean length from 40 nm to 100 nm). The nanorods are monocrystals, and they are organized side by side along their long axis, in a direction perpendicular to the substrate exposing a surface of tips. Such layers are superposed forming 3D superstructures. These nanorod superlattices are ferromagnetic at r.t. and they are characterized by a strong coercive field as a consequence of their large magnetic anisotropy (magnetocrystalline and shape). Upon application of an external magnetic field the organization is improved even further, and this improvement is partially retained even after field removal. Therefore, this system can be considered as a good candidate for high density magnetic recording. (c) 2006 Elsevier B.V. All rights reserved