Instrumental evaluations (e.g. Dobrzynski, InterNoise 90) showed that propeller noise can be reduced by asymmetrical blade spacing. Compared to conventional propellers with 6 blades and symmetrical spacing of 60°, propellers with asymmetric spacing of 15° produce about 3 dB(A) less level, in particular for high helical blade tip Mach numbers HBTMN. Since the aerodynamic propeller performance is...

The Savonius wind turbine is a type of vertical axis wind turbine (VAWTs) that is simply composed of two or three arc-type blades which can generate power even under poor wind conditions. A modified Savonius wind turbine with novel blade shapes is introduced with the aim of increasing the power coefficient of the turbine. The effect of blade fullness, which is a main shape parameter of the blad...

Currently the lifespan of rotor blades is determined based on a conservative lifetime calculation. This leads to blades being discarded while they still possess a significant residual amount of flight-hours. Blade health monitoring systems are desired to actively track the strains in the blade thereby drastically extending the technical life expectancy. A major drawback is in the need for an el...

An increasing number of high-performance distributed systems are written in garbage collected languages. This removes a large class of harmful bugs from these systems. However, it also introduces high tail-latency do to garbage collection pause times. We address this problem through a new technique of garbage collection avoidance which we call BLADE. BLADE is an API between the collector and ap...

In the Global South, pico- and micro-hydropower turbines are often made by local workshops. Despite several advantageous features, e.g., a high power density capacity to handle silt, there is no commonly available Turgo turbine design appropriate for manufacture. Technological developments including internet, CAD, additive manufacturing increase opportunity precisely transfer designs around wor...

in order to help in the engineering design of rice harvesting machines, there is a need to have exact information concerning the physical and mechanical properties of rice stems. the cutting force for rice stems, therefore, was measured by designing and fabricating a static and dynamic shear test apparatus. the effects of moisture levels and the cross-sectional area of stem as well as the varie...

development of new technologies and combined with creativity and innovation, plays the fundamental role in developing of any community′s value. thus, in this research the design and production of hydroforming device was introduced. one of the best and most efficient technologies in the world of metal forming is wind turbine blade producing with hydroforming method which seems as an innovative m...

this research was conducted to study morphological and evaluation of genetic diversity of 15 grape cultivars in collections of agriculture and natural resources, research center of khorasan razavi based on completely randomized design with four replications. results showed extensive range of variations among cultivars and measured traits. in some key traits of tests for distinctness uniformity ...

Polymer bulk hetero-junction solar cells of poly(3-hexylthiophene) (P3HT) donor and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) acceptor are fabricated by blade coating in toluene solution. Desired donor–acceptor self-organization is achieved without the slow drying process and high boiling point solvent. Power conversion efficiency is 3.8%, much higher than the 2.6% obtained by spin coat...

SUMMARY The Denton two-dimensional and three-dimensional time marching blade-to-blade computer programs have been used at NGTE to analyse the flow past transonic turbine blading. In this work experience has been gained in operating the programs and this paper describes the major findings in respect of how the programs have performed. Solutions for several blade sections, giving Mach number dist...