The Experts below are selected from a list of 4191 Experts worldwide ranked by ideXlab platform
Jun Hua Chen - One of the best experts on this subject based on the ideXlab platform.
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Study on the Inspection Method of Gas Valve’s External Taper Screw Thread Based on Image Domain
Advanced Materials Research, 2011Co-Authors: Xue Chang Zhang, Xu Zhang, Jun Hua ChenAbstract:The failure of the gas valve’s External Screw taper thread is a very serious problem which may result in accidents. Routine inspection on the threads is thus necessary. The efficiency of traditional manual testing methods can not meet the production requirements. An automatic visual inspection system for gas valve’s External Screw taper thread is presented in the paper. The system consists of a high-performance 200 mega pixels CCD camera, a LED backlight and a holder of gas valve. Through image acquisition, image processing, edge detection and feature dimension measurement, the system can effectively measure the parameters of taper thread such as half of thread angle, depth of thread, taper angle of thread on image domain. Due to the lead angle and installation error, actual half of thread angle is different from the theoretical values. Three methods are presented in the paper for the half of thread angle. Through analysis, Method 3 and Method 2 can be used to measure half of thread angle. The system can meet the testing requirements of the External Screw taper thread and has wide application perspective.
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Automatic Visual Inspection System of Gas Valve’s External Taper Thread Based on Image Domain
Applied Mechanics and Materials, 2010Co-Authors: Xue Сhang Zhang, Xu Zhang, Ying Hou Lou, Jun Hua ChenAbstract:The failure of the gas valve’s External Screw taper thread is a very serious problem which may result in accidents. Routine inspection on the threads are thus necessary. The efficiency of traditional manual testing methods can not meet the production requirements. An automatic visual inspection system for gas valve’s exteranl Screw taper thread was presented in the paper. The system consists of a high-performance 200 megapixels CCD camera, a LED backlight and a holder of gas valve. Through image acquisition, image processing, edge detection and feature dimension measurement, the system can effectively measure the parameters of taper thread such as angle of thread, depth of thread, taper angle of thread on image domain. It can meet the testing requirements of the External Screw taper thread and has wide application perspective.
John S. Mccaskill - One of the best experts on this subject based on the ideXlab platform.
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On demand nanoliter-scale microfluidic droplet generation, injection, and mixing using a passive microfluidic device.
Biomicrofluidics, 2015Co-Authors: Uwe Tangen, Abhishek Sharma, Patrick Wagler, John S. MccaskillAbstract:We here present and characterize a programmable nanoliter scale droplet-on-demand device that can be used separately or readily integrated into low cost single layer rapid prototyping microfluidic systems for a wide range of user applications. The passive microfluidic device allows External (off-the-shelf) electronically controlled pinch valves to program the delivery of nanoliter scale aqueous droplets from up to 9 different inputs to a central outlet channel. The inputs can be either continuous aqueous fluid streams or microliter scale aqueous plugs embedded in a carrier fluid, in which case the number of effective input solutions that can be employed in an experiment is no longer strongly constrained (100 s–1000 s). Both nanoliter droplet sequencing output and nanoliter-scale droplet mixing are reported with this device. Optimization of the geometry and pressure relationships in the device was achieved in several hardware iterations with the support of open source microfluidic simulation software and equivalent circuit models. The requisite modular control of pressure relationships within the device is accomplished using hydrodynamic barriers and matched resistance channels with three different channel heights, custom parallel reversible microfluidic I/O connections, low dead-volume pinch valves, and a simply adjustable array of External Screw valves. Programmable sequences of droplet mixes or chains of droplets can be achieved with the device at low Hz frequencies, limited by device elasticity, and could be further enhanced by valve integration. The chip has already found use in the characterization of droplet bunching during export and the synthesis of a DNA library.
Y.b. Liao - One of the best experts on this subject based on the ideXlab platform.
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Single-mode fiber-based reflex sensor for internal surface in-line measurement of small products
Sensors and Actuators A-physical, 2002Co-Authors: Yong Zhao, Y.b. LiaoAbstract:Abstract This paper describes experiments concerning dimension and surface shape measurement with a single-mode fiber-optic sensor and improvement of the measurement principle. The sensor probe was well designed with a small structure and a compensation network. The novel optical fiber probe arrangement as well as the possibilities for complex measurement problems is explained by measuring an internal Screw thread as an example. The size of the fiber-based sensor probe is about 5 mm, which is very suitable for the internal surface measurement of small precision products. The experimental results show that the measurement uncertainty of the internal Screw thread minor diameter can reach ±10 μm, and the stability of the measurement system is better than 0.1%. Compared the measurement results obtained by the developed sensor system with those by a Universal Tool Maker’s Microscope, the measurement results of an External Screw thread are satisfactory. The maximum deviation of the thread pitch measurement is about 1 μm, and that of the major diameter measurement is better than 3 μm.
G. Walker - One of the best experts on this subject based on the ideXlab platform.
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Screw-thread flow promoters: an experimental study of ultrafiltration and microfiltration performance
Journal of Membrane Science, 1995Co-Authors: H.r. Millward, Brian John Bellhouse, G. WalkerAbstract:Abstract The Screw-thread flow promoters presented in this work are designed to enhance filtration in a tubular geometry using a standard half-inch diameter. Two separate experimental studies were undertaken to evaluate the ultrafiltration of BSA and the microfiltration of bovine blood. The convective mixing in each system was augmented through a combination of two vortex patterns: helical flow around a semi-circular cross section and flow through a sudden expansion. The Screw-threads are simple to construct and operate well under laminar, quasi-steady flow conditions such that scale-up and the processing of shear sensitive fluids should be possible. The internal Screw-thread generated 75% of the clean water flux at a high BSA concentration of 60 g/l. The superposition of an oscillatory flow component on the mean flow did not significantly improve the performance. The internal Screw-thread design performed poorly when applied to the separation of plasma from whole blood because the centrifugal forces appeared to complement concentration polarization. An External Screw-thread design was found to be an effective anti-fouling technique and tripled the microfiltration performance relative to an internal Screw-thread. The lower pitch of 3.5 mm gave a plasma flux of order 0.1 cm/ min, moderate flux decline and no signs of haemolysis.
Gregory James Stout - One of the best experts on this subject based on the ideXlab platform.
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automotive vehicle steering system
2000Co-Authors: Brian J Andonian, Michael Kenneth Liubakka, Gregory James StoutAbstract:An automotive vehicle steering system has an actuator (26) disposed between steered wheels (12, 14) on opposite sides of the vehicle. A shaft (28) passes axially through the interior of a housing (40) of the actuator and through a rotor tube (56) journaled for rotation within the housing. On the exterior of the housing one end of the shaft is coupled to one wheel and the other end to the other wheel by respective tie rods (30, 32). An electric motor (52) within the interior of the housing rotates the rotor tube when the wheels are steered by a steering wheel. An internal Screw thread (68) on the rotor tube and an External Screw thread (70) on the shaft are operatively coupled by a set of transmission rollers (76) to provide for bi-directional transmission of motion between the rotor tube and the shaft such that rotation of the rotor tube causes the shaft to move axially of the housing to steer the vehicle wheels and axial motion of the shaft due to wheel recovery from a turn rotates the rotor tube.
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automotive vehicle steering system having an electric motor powered linear actuator shaft for turning a steered wheel
1999Co-Authors: Brian J Andonian, Michael Kenneth Liubakka, Gregory James StoutAbstract:An automotive vehicle steering system has an actuator (12) for steering a wheel (10). A shaft (28) passes axially through the interior of a housing (14) of the actuator and through a rotor tube (56) journaled for rotation within the housing. On the exterior of the housing one end of the shaft is coupled to the wheel. An electric motor (52) within the interior of the housing rotates the rotor tube when the wheel is steered by a steering wheel. An internal Screw thread (68) on the rotor tube and an External Screw thread (70) on the shaft are operatively coupled by a set (74) of transmission rollers (76) to provide for bi-directional transmission of motion between the rotor tube and the shaft such that rotation of the rotor tube causes the shaft to move axially of the housing to steer the vehicle wheel and axial motion of the shaft due to wheel recovery from a turn rotates the rotor tube.
