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a b s t r a c tThis paper presents several multi-megawatt offshore Darrieus vertical axis wind turbine (VAWT) projects currently under way. The projects are re-attempting large scale VAWT since Eole, the only multimegawatt Darrieus VAWT ever built, which was shut down in 1993. In addition, the project's timing is at the moment when horizontal axis wind turbine (HAWT) is facing major challenges in multi-megawatt range, especially for offshore wind power generation. The obstacles of large scale HAWT are elaborated, and the reasons of why Darrieus VAWT is key to the challenges are also explained. In addition, impacts of HAWT development on Darrieus VAWT are described. Lastly, the innovative designs on Darrieus VAWT are presented, which include current status of Sandia National Laboratories (SNL), novel offshore vertical axis (NOVA), Vertax and Vertiwind.

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Currently, solketal is produced from glycerol and acetone by using heterogeneous catalyst. However, a solid heterogeneous catalyst is not preferable since water contained in the glycerol, is adsorbed on the surface of the catalyst. Water could act as inhibitor in the reaction and lowering the activity of the catalyst. Therefore, homogenous acid catalyst is proposed to avoid the inhibition during the reaction. The aim of this research was to utilize sulphuric acid as the homogenous acid catalyst, to explore the effect of the mole ratio glycerol:acetone to the conversion, and determine the entrophy and entaphy of the reaction . The process was carried out in a three neck reactor equipped with a heater, temperature control, cooler and stirrer. The reaction conditions were set at a constant boiling temperature, the reaction time was varied at 4 - 12 h, and the mole ratio of acetone to glycerol was varied in the range of 2:1 - 7: 1. Results indicated that the highest conversion (>80 %) was recorded at 62°C, 10 h, and 6.9:1 mole ratio. The conversion of glycerol to solketal was influenced by mole ratio which is consistent to Lecatelier principle. From the entropy ΔS =280.02 J. mole K−1) and enthalpy ΔH= 95.948 J. mole−1), it can be concluded that the reaction of solketal formation was exothermic.

Chemical ingredients in rosella petals are very beneficial for health. Rosella petals needed to be drained for storage and packing purpose. The traditional drying takes 5 days and less healthy. Solar dryer technology can speed up the drying process and protect materials from dust contamination. Solar dryer with double glass covered collector has been designed and made for drying of agricultural products such as rosella flowers. Rosella petals as much as 2300 grams with initial moisture content of 90.84 % be dried with this dryer until the moisture content of 7.67 % takes only 2 days, although the weather was less sunny. The temperature in the drying chamber was not more than 50° C, so it was good for drying groceries, not damaging chemical ingredients. The relative humidity in the space dryeris was about 40 % and it was still relative low. Drying rate and drying performance was expressed by the efficiency and Specific Moisture Evaporation Rate (SMER) were influenced by water content of the dried material and weather. Daily efficiency at the first and the second day: 14.931 % and 5.78%, while the daily SMER on the first and the second day: 0.222 and 0.0256 (kg / kWh)..