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Renewable & Alternative Power Technologies
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Rotor/Blades: Most HAWTs have either two or three blades, though some designs feature as few as 1 or as many as 5 or more blades. Wind blowing over the blades causes them to lift and rotate. Since the speed at which the blades move at the tip will be greatest and decrease to zero at the hub, blades on larger turbines are twisted so as to achieve an optimal angle of attack all along the length of the blade. Blades are usually made of fiberglass, polyester, or epoxy resins. Some have wood cores. In pitch-controlled turbines, blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high for safe operation or too low to produce electricity. The blades and the hub together are called the rotor. The hub of the rotor is attached to the low-speed shaft. The hub may be attached to the drive shaft or a gear. Upwind machines have their rotor in front of the tower (wind hits the rotor before the tower) and downwind machines have the reverse arrangement. Figure 14-23 shows the final stages of turbine blade fabrication for a large Micon unit and Figure 14-24 shows a blade undergoing a modal test. The blade is instrumented with accelerometers, which feed the frequency of oscillation into a computer upon being struck with a calibrated instrumental hammer. Figure 14-25 shows an innovative five-bladed rotor on an 80 kW turbine.
Manufacturing Products
Published in Roger Timings, Basic Manufacturing, 2006
Knives are used for cutting and for trimming such materials as food, plastics, wood, card, glass fibre roving and leather. The correct type of knife should be selected for the process to be carried out. Knife blades should be kept clean and sharp and when not in use should be covered or sheathed to prevent damage to the cutting edge and for safety. Knives may have blades that are fixed, adjustable, retractable or disposable.
Make blades very sharp
Published in Michael Wiklund, Kimmy Ansems, Rachel Aronchick, Cory Costantino, Alix Dorfman, Brenda van Geel, Jonathan Kendler, Valerie Ng, Ruben Post, Jon Tilliss, Designing for Safe Use, 2019
Michael Wiklund, Kimmy Ansems, Rachel Aronchick, Cory Costantino, Alix Dorfman, Brenda van Geel, Jonathan Kendler, Valerie Ng, Ruben Post, Jon Tilliss
Of course, there is the tried-and-true method of blade sharpening using muscle and a sharpening device. There are plenty of standalone sharpeners that simply require one to draw the blade through a groove. There are also a wide variety of grinders, sharpening stones, and devices with an equivalent purpose that give the user the pleasure of gauging the blade angle and doing his or her own shaping and honing.
Investigation of abrasive saw kickback
Published in International Journal of Occupational Safety and Ergonomics, 2022
Steven Burcat, Brian Yue, Alexander Slocum, Tal Cohen
The second simplification, referred to as Model 2, treats the cutting blade as a second rigid body connected to the saw body by a pinned joint at O. The cutting blade is assumed to have a negligible mass relative to the saw body. In this case, the force applied to the blade during kickback through the pinch is transmitted to the saw body through the center of rotation of the cutting blade, O. Because the mass of the cutting blade is negligible, the full kickback force is seen by the saw body and is in the same direction as it would be on the cutting blade. In this case, the resulting equations of motions are slightly different, as seen in Equations (7) and (8): where M = mass of the saw body; rC = vector from P to C; F = force vector; I = moment of inertia of the saw; θ = angle between rCO and the x axis; rCO = vector from C to O; two superimposed dots/double over dot = two differentiations with respect to time.
Cut resistant property of weft knitting structure: a review
Published in The Journal of The Textile Institute, 2018
Lijuan Wang, Kejing Yu, Diantang Zhang, Kun Qian
According to the research by other scholars, the mechanical model in the cutting process is affected by the following factors:The real contact area of blade and material. Cutting force in the cutting process strike on the blade is different, according to different areas of thrust surface. The cutting edge of the blade is the line, hypothesis of the same cut momentum, if the contact line is short, and average force is large, vice versa.The material undergoes plastic deformation on the cutting force.The mechanical properties of material on the application of load, e.g. tribological properties of fabric surface, tear resistance, and shear performance of the material, which relates to fabric structure and yarn properties.
Microparticles with diverse sizes and morphologies from mechanical and laser cutting of fuel debris simulants and geopolymer as a covering material
Published in Journal of Nuclear Science and Technology, 2021
Qian Zhou, Takumi Saito, Seiya Suzuki, Kimihiko Yano, Shunichi Suzuki
For the mechanical cuttings, samples were cut with a band saw machine (Shindaiwa, RB120FV, 200 W output, 0.5 mm high-speed steel blade, 44 m/min peripheral velocity) or a manual cutting tool (1.3 mm diamond saw blade). The band saw machine was only used on the cutting of geopolymer since the surrogate samples are small in size and difficult for machinery cuttings and particle collections. Similar data were obtained from the band saw cutting and manual cutting of geopolymer, which showed that the different approaches in mechanical cuttings only had minor influences on the particle size distributions and had no obvious impacts on the particle morphologies.