The energy crisis has forced researchers to look for various non-conventional sources. Wind is one of the potential sources, and have invested resources in developing different kinds wind turbines. Vertical axis turbines (VAWT) received less attention than their horizontal-axis counterparts. A helical-bladed VAWT preferred because it makes perfect sense as an improvement design, they higher azi...

in in order to investigating changes range of oil yield and percentage attention to plant density on three varieties of black seed, an experiment was conducted in the form of factorial based on completely randomized block designs (rcbd) with 4 replications in saat-loui agricultural station of west azerbaijan province. in this research, the first factor (a) contained two levels 20 and 40 cm inte...

Typically, cost–benefit analysis (CBA) has suggested ‘optimal’ carbon tax regimes that result in a global temperature rise of around 3 °C, or even eventually (post-2100) 4 °C, above preindustrial levels. However, risk analysis approaches indicate that these levels of temperature rise result in climate change impacts that pose a high or very high level of risk to society and ecosystems1 (Fig. 1)...

The forces on a turbine at extreme wind conditions when the turbine is parked is one of the most important design cases for the survivability of a turbine. In this work, the forces on a blade and its support arms have been measured on a 12 kW straight-bladed vertical axis wind turbine at an open site. Two cases are tested: one during electrical braking of the turbine, which allows it to rotate ...