disadvantage was poor knowledge of materials characteristics and behaviors at high temperatures. The best metallurgy of the day could not prevent the turbine disks from moving and warping unacceptably during operation. Many amateur experiments have been conducted using Tesla turbines with compressed air, or steam as the power source (the steam is generated with heat from fuel combustion or solar radiation). Disc warping has been ameliorated by using new materials such as carbon fiber. One proposed application for the device is a waste pump, in factories and mills where normal vane-type turbine pumps typically become fouled. Applications of the Tesla turbine as a multiple-disk centrifugal blood pump have yielded promising results due to the low peak shear force. Biomedical engineering research on such applications has continued into the 21st century. The device functions as a pump if a similar set of disks and a housing with an involute shape (versus circular for the turbine) are used. In this configuration, a motor is attached to the shaft. The fluid enters near the center, is energized by the disks, then exits at the periphery. The Tesla turbine does not use friction in the conventional sense; precisely, it avoids it and uses adhesion (the Coandă effect) and viscosity instead. It uses the boundary-layer effect on the disc blades. See also List of Tesla patents Radial turbine Tesla coil References Further reading Tesla, Nikola, "Dr. Tesla Talks Of Gas Turbines". Motor World. September 18, 1911. US1061206 Turbine - New and useful Improvements in Rotary Engines and Turbines US1329559 Valvular Conduit - Includes the Tesla gas turbine GB186082 Improvements in the Construction of Steam and Gas Turbines - Form of rotor GB186083 Economic Transformation of the Energy of Steam by Turbines - Tesla turbine system , Disc turbine inlet to assist self-starting, Letourneau (February 11, 2002) , Labyrinth seal for disc turbine, Letourneau (February 13, 2002) , Rotor assembly for disc turbine, Letourneau (March 15, 2002) , Method of and apparatus for a multi-stage boundary layer engine and process cell, Hicks (December 13, 2005) External links Vanderbilt Tesla Turbine Tesla turbine, from Uncle Taz Library Tesla Turbine Kit, Turbo-Generator, from OBI Laser Products Tesla Turbine featuring the work of Ken Rieli and others Building a Tesla turbine using hard disk platters Rice, Warren, ""Tesla Turbomachinery." Proc. IV International Nikola Tesla Symposium, Sept. 23-25, 1991 Redmond, Stephen, "Building a Disk Turbine" Germano, Frank D., "Tesla's Bladeless