Performance of Air-Lubricated Hydrodynamic Bearing Spindles for Laser Scanners

1991 ◽  
Vol 113 (3) ◽  
pp. 609-614 ◽  
Author(s):  
K. Tanaka ◽  
H. Muraki
Keyword(s):  
High Speed ◽  
High Performance ◽  
Experimental Results ◽  
Hydrodynamic Bearing ◽  
Vibration Resistance ◽  
High Speeds ◽  
Laser Printers ◽  
Laser Scanners

This paper reports on the performance of air-lubricated bearing spindles for high-speed laser scanners using newly developed bearings. Experimental results confirmed that these spindles have adequate performance including floating stability, endurance, vibration-resistance at high-speeds, and start-stop endurance for laser scanners. These spindles are already mass-produced and used in laser printers and digital color copiers, so their high performance and endurance are proven.

The Measurement and Analysis of Ball Motion in High Speed Deep Groove Ball Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 341-348 ◽  
Author(s):  
R. J. Boness ◽  
J. J. Chapman
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Complete Analysis ◽  
Ball Speed ◽  
Rolling Axis ◽  
High Speeds ◽  
Deep Groove ◽  
Wide Range ◽  
Ring Mode ◽  
Ball Motion

This paper reports on a study of ball motion, including the measurement of ball rolling axis, in deep groove bearings operating at high speeds under thrust load conditions. The technique employed relies on viewing the test bearing, operating in the conventional fixed outer ring mode, through a rotating prism which eliminates optically the gross rotation of the separator. Videotape recordings of a selected ball, distinctively marked and illuminated stroboscopically, allows a complete analysis of ball bearing kinematics. Experimental results of separator speed, ball speed and rolling axis together with separator slip, ball slip and spin velocities at both the inner and outer raceway contacts are presented for a wide range of loads and shaft speeds up to 12,000 rev/min. These results are compared with the existing theory of Jones. Discrepancies between predicted and actual ball motion are due to the assumption made by Jones in neglecting bearing element slip. A further analysis of the experimental results including both gyroscopic torques and slip based on elastohydrodynamic traction values for the test lubricant explains actual ball motion more fully.

The Role of High Performance Foil Bearings in Advanced, Oil-Free, High-Speed Motor Driven Compressors

2003 ◽  
Author(s):  
James F. Walton ◽  
Michael J. Tomaszewski ◽  
H. Heshmat
Keyword(s):  
High Speed ◽  
High Performance ◽  
Development Program ◽  
Foil Bearings ◽  
High Speeds ◽  
Start Up ◽  
Rolling Element ◽  
Temperature Capability ◽  
Full Speed ◽  
Bearing System

The demand for high power density, reliable, low maintenance, oil-free turbomachinery imposes significant demands on the bearing system. The full benefits of high speed, motor driven machines, for example are realized at speeds exceeding the capabilities of rolling element bearings. The high speeds, and requirement for oil-free operation in fuel cell applications also make conventional liquid lubricated bearings an undesirable alternative. The modern, oil-free foil bearing provides an excellent alternative, with its low power loss, damping for smooth high-speed operation and shock tolerance, elevated temperature capability and long maintenance free life. In this paper, the application of modern foil bearings to two different high-speed, oil-free compressors is discussed. In each application, foil bearings support a multi-component rotor operating at speeds above 70,000 RPM. Stable and reliable operation over the full speed range is demonstrated in each case. These applications also required low bearing start-up torque for compatibility with the torque characteristics of the integral motor. This work discusses the rotor bearing system design, the development program approach, and the results of testing to date.

scholarly journals Review on the Effect of the Phenomenon of Cavitation in Combustion Efficiency and the Role of Biofuels as a Solution against Cavitation

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7265
Author(s):  
Ludovic Lamoot ◽  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Nicolas Gascoin
Keyword(s):  
High Speed ◽  
High Performance ◽  
Research Work ◽  
Combustion Process ◽  
Energy Transition ◽  
Combustion Efficiency ◽  
Review Article ◽  
Cavitation Phenomenon ◽  
Heat Engines ◽  
High Speeds

Concerning the problem of wanting the performance of heat engines used in the automotive, aeronautics, and aerospace industries, researchers and engineers are working on various possibilities for improving combustion efficiency, including the reduction of gases such as CO, NOx, and SOx. Such improvements would also help reduce greenhouse gases. For this, research and development has focused on one factor that has a significant impact on the performance of these engines: the phenomenon of cavitation. In fact, most high-performance heat engines are fitted with a high-speed fuel supply system. These high speeds lead to the formation of the phenomenon of cavitation generating instabilities in the flow and subsequently causing disturbances in the combustion process and in the efficiency of the engine. In this review article, it is a question of making a state-of-the-art review on the various studies which have dealt with the characterization of the phenomenon of cavitation and addressing the possible means that can be put in place to reduce its effects. The bibliographic study was carried out based on five editors who are very involved in this theme. From the census carried out, it has been shown that there are many works which deal with the means of optimization that must be implemented in order to fight against the phenomenon of cavitation. Among these solutions, there is the optimization of the geometry of the injector in which the fuel flows and there is the type of fuel used. Indeed, it is shown that the use of a biofuel, which, by its higher viscosity, decreases the effects of cavitation. Most of these jobs are performed under cold fluidic conditions; however, there is little or no work that directly addresses the effect of cavitation on the combustion process. Consequently, this review article highlights the importance of carrying out research work, with the objective of characterizing the effect of cavitation on the combustion process and the need to use a biofuel as an inhibitor solution on the cavitation phenomenon and as a means of energy transition.

scholarly journals Evaluation of Meshed Reference Planes for High Performance Applications

2000 ◽  
Vol 22 (3) ◽  
pp. 175-187 ◽  
Author(s):  
N. D. Codreanu ◽  
P. Svasta ◽  
V. Golumbeanu ◽  
L. Gál
Keyword(s):  
Integrated Circuits ◽  
High Frequency ◽  
High Speed ◽  
High Performance ◽  
Network Analyzer ◽  
High Frequencies ◽  
High Speeds ◽  
University Of Budapest ◽  
Very High Frequencies ◽  
Very High

The actual generations of integrated circuits are characterized, inter alia, by very high frequencies or very high speeds. The dramatic evolution ofthe semiconductor's technology establishes a greater “pressure” to the design and the manufacturing of the passive interconnection structure from PCB/MCM electronic modules. In these conditions the reference planes (power and ground planes) have a more and more important contribution. The paper intents to present the effect of different configuration reference planes on the characteristics of the high speed/high frequency interconnection lines. The first part deals with modeling and simulation of usual practical interconnection geometries. A computer modeling of meshed structures was realized and Spice models for a good compatibility with circuit simulators were obtained.S-,Y-,Z- parameters and radiation patterns were calculated, too. The second part contains measurements made by a vector network analyzer as regards to different practical configurations manufactured at Technical University of Budapest.

A LANDMARK-BASED NAVIGATION SYSTEM FOR HIGH SPEED CARS IN THE ROADS WITH BRANCHES

2009 ◽  
Vol 06 (03) ◽  
pp. 193-202
Author(s):  
MERCEDEH SANJABI ◽  
SOMAYEH MAABI ◽  
ZAHRA ESMAEILI ◽  
ALI JAHANIAN ◽  
SIRVAN KHALIGHI
Keyword(s):  
Embedded System ◽  
Real Time ◽  
High Speed ◽  
Small Error ◽  
Experimental Results ◽  
Automotive Systems ◽  
High Speeds ◽  
Simple Detection ◽  
Road Maps ◽  
Car Navigation

Landmark-based car navigation is a widely used technique for automotive and robot navigation. Wireless landmarks have some key features such as robustness and simple detection that make them suitable for automotive navigation. In this paper, a light-weight embedded algorithm for high speed car navigation in the roads with branches is presented which can be efficiently used in real-time automotive systems. We implemented the proposed algorithm on a real-time MIPS-based embedded system and analyzed its accuracy and efficiency in some real road maps, especially for high speed movements in real roads. Experimental results show that the proposed algorithm can be used for high speeds (up to about 360 km/h) with a very small error rate. Additionally, the experimental results show that the power consumption of the proposed system is suitable for built-in car applications.

scholarly journals Measurement of Rigidity Change of Preload Switching Spindle

2012 ◽  
Vol 6 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Taku Yamazaki ◽  
◽  
Atsushi Matsubara ◽  
Shinya Ikenaga ◽  
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Rigidity ◽  
High Speeds ◽  
Loading Device ◽  
Magnetic Loading ◽  
Simulation Results ◽  
Load Displacement ◽  
Low Speeds ◽  
Relationship Of

High performance milling spindles with high rigidity and high speed are required for high productive machining. A preload switching spindle has been designed to obtain high rigidity at low speeds while avoiding bearing burn at high speeds. In this report, the load-displacement relationship of a preload switching spindle is measured with a non-contact magnetic loading device. Measurement and simulation results are compared to clarify the rigidity change by preload switching.

Modeling of High Performance 4H-SiC Emitter Coupled Logic Circuits

2014 ◽  
Vol 778-780 ◽  
pp. 1009-1012 ◽  
Author(s):  
Shakti Singh ◽  
Nourhan El Sayed ◽  
Hazem Elgabra ◽  
Tamador ElBoshra ◽  
Maisam Wahbah ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
High Temperatures ◽  
High Speed ◽  
High Performance ◽  
Wide Band ◽  
Bipolar Transistors ◽  
Small Scale ◽  
Wide Band Gap ◽  
High Speeds ◽  
Wide Range

SiC, a wide band gap semiconductor, is capable of robust operation at temperatures well above 600°C. SiC bipolar transistors are well suited for applications at high temperatures as, unlike MOSFET, it does not have a critical gate oxide, and hence oxide reliability at high temperatures is not an issue. In this paper, the design of optimized emitter coupled logic technology circuits using 4H-SiC bipolar transistors is presented. The circuits work over a wide range of temperatures and power supply voltages at high speeds, demonstrating the potential of robust high speed ECL integrated circuits in SiC for small-scale logic applications.

scholarly journals Avian-Inspired Grasping for Quadrotor Micro UAVs

2013 ◽  
Author(s):  
Justin Thomas ◽  
Joe Polin ◽  
Koushil Sreenath ◽  
Vijay Kumar
Keyword(s):  
Unmanned Aerial Vehicles ◽  
High Speed ◽  
Bald Eagle ◽  
Experimental Results ◽  
Birds Of Prey ◽  
Nonlinear Dynamic Model ◽  
Video Footage ◽  
High Speeds ◽  
Wide Range ◽  
Aerial Hunting

Micro Unmanned Aerial Vehicles (MAVs) have been used in a wide range of applications [1, 2, 3]. However, there are few papers addressing high-speed grasping and transportation of pay-loads using MAVs. Drawing inspiration from aerial hunting by birds of prey, we design and equip a quadrotor MAV with an actuated appendage enabling grasping and object retrieval at high speeds. We develop a nonlinear dynamic model of the system, demonstrate that the system is differentially flat, plan dynamic trajectories using the flatness property, and present experimental results with pick-up velocities at 2 m/s (6 body lengths / second) and 3 m/s (9 body lengths / second). Finally, the experimental results are compared with observations derived from video footage of a bald eagle swooping down and snatching a fish out of water.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

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