The extensive design effort for KSTAR has been focused on two major aspects of the KSTAR
project mission - steady-state-operation capability and advanced tokamak physics. The steady
state aspect of the mission is reflected in the choice of superconducting magnets, provision of
actively cooled in-vessel components, and long pulse current drive and heating systems. The
advanced tokamak aspect of the mission is incorporated in the design features associated with
flexible plasma shaping, double null divertor and passive stabilizers, internal control coils and
a comprehensive set of diagnostics. Substantial progress in engineering has been made on
superconducting magnets, the vacuum vessel, plasma facing components and power supplies. The
new KSTAR experimental facility with cryogenic system and deionized water cooling and main
power systems has been designed, and the construction work is under way for completion
in 2004.
The Korea Superconducting Tokamak Advanced Research (KSTAR)
project is the major effort of the national fusion programme of the Republic of Korea. Its aim is
to develop a steady state capable advanced superconducting tokamak to
establish a scientific and technological basis for an attractive fusion
reactor. The major parameters of the tokamak are: major radius 1.8 m, minor
radius 0.5 m, toroidal field 3.5 T and plasma current 2 MA, with a
strongly shaped plasma cross-section and double null divertor. The initial
pulse length provided by the poloidal magnet system is 20 s, but the pulse
length can be increased to 300 s through non-inductive current drive. The
plasma heating and current drive system consists of neutral beams,
ion cyclotron waves, lower hybrid waves and electron cyclotron waves for
flexible profile control in advanced tokamak operating modes. A
comprehensive set of diagnostics is planned for plasma control,
performance evaluation and physics understanding. The project has
completed its conceptual design and moved to the engineering design and
construction phase. The target date for the first plasma is 2002.
This paper presents an initial investment cost analysis of public transportation systems operating with wireless charging electric vehicles (EVs). There are three different types of wireless charging systems, namely, stationary wireless charging (SWC), in which charging happens only when the vehicle is parked or idle, quasi-dynamic wireless charging (QWC), in which power is transferred when a vehicle is moving slowly or in stop-and-go mode, and dynamic wireless charging (DWC), in which power can be supplied even when the vehicle is in motion. This analysis compares the initial investment costs for these three types of charging systems for a wireless charging-based public transportation system. In particular, this analysis is focused on the energy logistics cost in transportation, which is defined as the cost of transferring and storing the energy needed to operate the transportation system. Performing this initial investment analysis is complicated, because it involves considerable tradeoffs between the costs of batteries in the EV fleet and different kinds of battery-charging infrastructure. Mathematical optimization models for each type of EV and infrastructure system are used to analyze the initial costs. The optimization methods evaluate the minimum initial investment needed to deploy the public transportation system for each type of EV charging solution. To deal with the variable cost estimates for batteries and infrastructure equipment in the current market, a cost-sensitivity analysis is performed. The goal of this analysis is to identify the market cost conditions that are most favorable for each type of wireless charging solution. Furthermore, the cost analysis quantitatively verifies the qualitative comparison of the three different wireless charging types conducted in the previous research.
In this paper, shear rate-dependent rheological properties of mine tailings taken from abandoned mine deposits prone to mass movements are examined using a commercial ball-measuring rheological system. The yield stresses (i.e., dynamic and static yield stresses) and viscosity of sand-rich materials are examined by the shear rate-controlled flow curve and time-dependent stress growth methods. Before yielding, the shear stress reaches a peak value (i.e., yield stress) observed for all flow curves. In the steady-state condition, the materials have a minimum shear stress (i.e., dynamic yield stress). The static yield stress can be determined under a constant applied shear rate with different initial values ranging from 10−4 to 10−1 s−1. As a result, the Bingham yield stress and viscosity can be used as a first approximation for estimating the debris flow mobility of post-failure materials. However, the Bingham yield stress is competitive with the static yield stress measured from stress growth methods. Upon comparison of the dynamic and static yield stresses, the static yield stress is approximately 35–45 times greater than the dynamic yield stress, and may be strongly related to microstructural changes (i.e., thixotropy). In this context, special attention must be paid to the determination of yield stresses in debris flow mitigation programs.
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