A Break-through in Energy Resources
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Experimental Mechanics Forum
Free (Reaction Less) Torque Generation – Fiction or Reality
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Dear Sirs, I just wonder do you have interest in Free (Reaction less) Torque Generation.
Choosing a Universal Testing Machine
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I am in the process of buying a universal testing machine, and have found the process to be quite confounding. My main area of expertise is computational mechanics, but I decided to add a materials testing capabiity to my program to support my constitutive model development efforts. I am surprised that, given how expensive these machines are, that there's isn't a user generated comparison website or online forum relating experiences or comments regarding these machines, their software, accessories, etc....
Best load cell for testing small structures - what have you found?
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For all of the small-scale mechanics testing to date, there seems to be a lack of load/force cells that combine a number of desirable features including vacuum compatibility, high resonant frequency, and sub-microNewton resolution.
Measuring Fiber Force in Composites
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Hi All,
I am looking for a experimental apparatus, technique or commercial equipment which can measure the force in fibers in a composite laminate. I would like to measure the cord force in one of the fibers for some FEA validation study.
Guide vanes flutter/vibration
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Greetings co-researchers,
I am currently designing a full-scale Impulse turbine (2 to 3 m diameter, 0.5 hub to tip ratio) for extracting of energy from waves.The turbine will be connected to a shore based device oscillating water column (OWC), so the airflow through the turbine is bidirectional (i.e. reverses as the wave enters and recedes in the OWC). This means we have to use symmetrical entry and exit guide vanes. These vanes are fixed, not movable.· The guide vanes are slender, approximately; height 700mm, chord length 600mm and thickness 2 to 5mm. Their role is to redirect the air flow from the axial direction to an angle of 60o · The rotor rotation speed is low (100 RPM to 1000 RPM). · The airflow is incompressible (Mach number < 0.3) and unsteady as it is related to the wave energy, which means the mass flow inlet to the turbine changes randomly (from zero to a maximum value say 10kg/s). One of the good approximations to this airflow is a sinusoid, but even this is extremely difficult to simulate in Fluent 6.2 CFD.I have done some preliminary forced vibration response analysis of the guide vanes. As far as I can see, the main cause of any vibration of the guide vanes would be the changes on pressure caused by the chopping of the flow by the rotor (i.e. the passing frequency of the rotor/guide vanes assembly). I plan to measure these pressure variations using pressure tapings on an experimental turbine test rig.
Please could you comment whether in your experience the main source of guide vane vibration would be the chopping of the fluid flow by the rotor. Also I would appreciate it if you have done any experimental or analytical data on this problem.
Lift weight using less energy
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As shown in figure(energyefficiency1.jpg) sliding plates can slide over fixed plates. Stationary plate is simply supported horizontaly on sliding plates. Lubrication is provided at contact surfaces of stationary plate and sliding plates. Weight or load or force (mg) is applied at center of stationary plate. This load is equally devided and applied on each sliding plate in vertical downward direction (mg/2). This mg/2 cos(alpha) helps sliding plate to slide in nearly downward direction.
Rotate pulleys using less energy
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Cross section of pulley1, pulley2 , pulley3 and pulley4 are as shown in figure. Center of Pulley 1 and pulley 2 are placed on same horizontal line. Center of pulley 1 and pulley 2 are fixed. Pulley 1 and pulley 2 can rotate about their center. Center of pulley3 and pulley4 are also placed on one horizontal line. Pulley 3 and pulley 4 can also rotate about their center. Center of pulley 3 and pulley4 are joined with one stationary plate.Pulley 3 and pulley4 are simply supported on pulley1 and pulley2.Now we apply some load or weight on stationary plate. Finaly this force is applied on pulley 1 and pulley 2 in vertical downward direction because pulley 3 and pulley4 are simply supported on pulley 1 and pulley2. Tangential componants of these force helps to rotate pulley1 , pulley2 , pulley3 and pulley4. If you want to remove pulley3 and pulley4 , stationary plate is directly simply supported on pulley1 and pulley2 then also pulley1 and pulley2 can be rotated.Pl visit http://www.energyefficiency.zoomshare.com/
Research cooperation wanted to develop a new type of nanoRAM
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Recently, we proposed a new concept to construct nano random access memory (nanoRAM) using carbon nanotubes. One of the most singnificant advantages of our design is that a RAM element is composed of only one single carbon nanotube. We are now looking for universities, companies and individuals who can perform experimental investigations on the electromechanical behavior of carbon nanotubes to realize this theoretical design.