Modelling boundary-induced coupling currents in Rutherford-type cables

In this paper it is shown that spatial distributions in the field-sweep rate and in the contact resistances along the length of Rutherford-type cables provoke a non-uniform current distribution during and after a field sweep. This process is described by means of Boundary-Induced Coupling Currents (BICCs) flowing through the strands over lengths far larger than the cable pitch. The dependence of the BICCs on the cable parameters (geometry, contact resistances etc.) is investigated by modelling the cable by means of a comprehensive network model. Working formulas are presented that give a first estimate of the characteristic time, the amplitude, and the characteristic length of the BICCs in any kind of magnet wound from a Rutherford-type cable. The results of these calculations show that BICCs can attain large values in multistrand cables, and hence play an important role in the ramp-rate limitation and field quality of high-field accelerator magnets even if the field-sweep rate is small

Landscape ecological Decision & Evaluation Support System LEDESS : users guide

To understand the basic strategies in nature development, it is necessary to examine existing plans and schemes in order to reveal and clarify underlying concepts. Two questions are crucial here: what is the ecological objective, and what is the spatial strategy? The first question is related to the level of the ecosystem. With different types of nature management, different ecosystems can develop at the same site. Nature policy decides which system is to be developed. The second question is related to the landscape as a whole, the spatial pattern of ecosystems. It is taken into account that other activities, such as farming, recreation, water supply and quarrying, also require space. Nature development cannot be considered independently from those activities. Therefore, a spatial strategy is required to combine all land use functions. To find an optimal balance between the two questions, different nature development scenarios are developed

Critical Current Measurements of the Main LHC Superconducting Cables

For the main dipole and quadrupole magnets of the LHC, CERN has ordered from industry about 7000 km of superconducting Nb-Ti Rutherford type cables, delivered between 1999 and 2005. The strands of these cables are produced by six different companies, and cabled on five different machines. In the framework of the US contribution to the LHC, BNL has been testing and analyzing the electrical properties of samples of these cables. The main purpose of these tests was to qualify the critical current of the entire cable production in the frame of the quality assurance program implemented by CERN to assure the overall strand and cable performances. In total more than 2100 cable samples have been evaluated at 4.3 K in terms of critical current $I_{C}$, n-value and the residual resistance ratio, RRR. This paper will present an overview of the results, and show the correlations of the critical current and n-value between virgin strands, extracted strands, and cables. Also described are correlations of $I_{C}$ measured at BNL and those made at the FRESCA facility in CERN. Furthermore a few trends and anomalies of the cable production that were detected from testing cables are highlighted

Knowledge management for small languages

In this paper an overview of the knowledge components needed for extensive documentation of small languages is given. The Language Archive is striving to offer all these tools to the linguistic community. The major tools in relation to the knowledge components are described. Followed by a discussion on what is currently lacking and possible strategies to move forward

An application framework for exploring the sustainability limits: the case of climate change impacts in Brazil.

In the era of development, technological evolution and population expansion, policies play a fundamental role in the maintenance of the economic, social and environmental wellbeing. Sustainable development is the general target of society to be ensured by policy decisions considering climate change, biodiversity loss, protection of endangered species, and so forth. Indicators have a fundamental role in providing new insights and clear statements by assessing progress and defining behaviours. In this paper, we test an application framework for the exploration of sustainability limits. We developed a set of sustainability limits for indicators and applied them in a Latin American context. We used QUICKScan, a tool to support the decision in participatory processes., by attempting to visualize any conceptual scenarios. Brazil was the case study country and the indicators used are: forest area coverage, carbon sequestration, the probability of being infected by Leishmaniosis and available water per capita. We present some results which illustrate the complexity of managing land use for multiple services, and the trade-offs that inevitably result. By visualizing the current situation and comparing outcomes under future scenarios, we can support discussion with local experts to explore the policy options at local to regional scales

Tensile stress in a porous mediumdue to gas expansion

Stress profiles develop in a porous material due to a gas-phase pressure difference and subsequent gas flow. If stresses become tensile, material failure (explosion and blistering) can occur. Stress profiles are calculated for an asymmetric inorganic porous disk-like membrane material placed in a pressure vessel, which is depressurized. The stress that develops in the membrane material depends on the gas-phase pressure and the porosity. The gas-phase pressure is a function of place, time and characteristics of the membrane, the vessel and the valve. Two regimes are identified for membrane depressurization, and a critical initial pressure is defined below which tensile stresses cannot develop. The theory presented combines the dusty gas model with balances for mass, momentum, and mechanical energy

Modelling of constant voltage electrophoretic deposition from a stirred suspension

In electrophoretic deposition, a voltage difference is applied across a suspension, and a layer (cast or coating) is formed on one of the electrodes. Based on first principles, cast growth is described in this work for a well-stirred suspension, a constant voltage difference across the deposition cell, and a nonionic solution. The influence of cast formation on cast growth is implemented, which is a refinement of the model described in 1999 by Biesheuvel and Verweij. Simulation results are compared with experimental data. From the derivation it follows that a smooth cast layer is formed when the particle permittivity is lower than that of the liquid. Catastrophic cast growth occurs when the particle permittivity is higher than that of the liquid

Boundary-induced coupling currents in a 1.3 m Rutherford-type cable due to a locally applied field change

In this paper the existence of so called Boundary-Induced Coupling Currents (BICCs) is experimentally demonstrated in a 1.3 m long Rutherford-type cable. These BICCs are induced by applying a field change locally onto the cable and can be represented by a non-uniform current distribution between the strands of the cable during and after the field sweep. In order to better understand the characteristic time, amplitude and characteristic length of these coupling currents and the parameters by which they are influenced, a special set-up has been built. With this set-up it is possible to scan the field induced by the BICCs along the full length of a Rutherford-type cable. Special attention is paid on the influence of the contact resistance between crossing strands on the characteristics of the BICCs, and results are presented where parts of the cable are soldered, simulating the joints of a coil