Heat absorption properties of ground material for solar chimney power plants

One of the major challenges to the widespread application of the solar chimney power plant is its low-power conversion efficiency because of the three technological processes involved. The chimney efficiency is difficult to improve, and thus enhancing the collector or turbine performance can considerably improve the total plant efficiency. This work focused on enhancing the energy conversion efficiency of the collector and also extending the operation time using a heat storage medium. The solar to thermal conversion and thermal storage capabilities of six ground materials that are potentially available in Malaysia were studied experimentally and numerically. The experimental model was designed such that the six materials were exposed to the same operation boundary conditions. The numerical studies were conducted using ANSYS software, where the geometrical models were developed and simulated using FLUENT for the fluid flow and energy/thermal field studies. The selected ground materials were ceramic, black stones, sawdust, dark-green painted wood, sand, and pebbles. The simulation and experimental results are in good agreement in terms of air stream velocity and energy conversion efficiency. The results showed that the different materials have different heat storage capacities, and that ceramics extend the operation with improved efficiency until nighttime. The results also showed that ceramic and black stones have better performance than the other materials. However, black stones are recommended as the absorbing material for solar chimney power plants in Malaysia and regional countries because they are readily available

RRS James Cook Cruise 30, 26 Dec 2008-30 Jan 2009. Antarctic Deep Water Rates of Export (ANDREX)

This report describes scientific activities on RRS James Cook cruise 30, “ANDREX”, westwards from 30°E and in the vicinity of latitude 60°S, between late December 2008 and late January 2009. The cruise was terminated about halfway through by a medical emergency. Hydrographic work comprised 27 CTD/LADCP stations. Water samples were captured for measurement of salinity, dissolved oxygen, inorganic nutrients, oxygen isotope fraction, chlorofluorocarbons and sulphur hexafluoride, dissolved inorganic carbon and alkalinity, helium / tritium / noble gases and radiocarbon. Underway measurements comprised navigation, currents (ADCP), meteorology, and sea surface temperature and salinity. The remainder of the hydrographic section was executed a year later on RRS James Clark Ross, cruise JR239

Trade-off between complexity and BER performance of a polynomial SVD-based broadband MIMO transceiver

In this paper we investigate non-linear precoding solutions for the problem of broadband multiple-input multiple output(MIMO) systems. Based on a polynomial singular value decomposition (PSVD) we can decouple a broadband MIMO channel into independent dispersive spectrally majorised single-input single-output (SISO) subchannels. In this contribution, the focus of our work is to explore the influence of approximations on the PSVD, and the performance degradation that can be expected as a result