scholarly journals Recent Trends in System-Level EMC Investigation and Countermeasure Technology for RF Interference Due to High-Speed Digital System Noise

2014 ◽  
Vol 25 (10) ◽  
pp. 966-982 ◽  
Author(s):  
Tae-Wan Koo ◽  
Ho Seong Lee ◽  
Jong-Gwan Yook
Keyword(s):  
High Speed ◽  
Digital System ◽  
System Level ◽  
System Noise ◽  
Recent Trends

Assessment of Viscous Flows in High-Speed Micro Rotating Machinery for Energy Conversion Applications

2001 ◽  
Author(s):  
Luc G. Fréchette
Keyword(s):  
Shear Flow ◽  
Energy Conversion ◽  
Viscous Flow ◽  
High Speed ◽  
Applied Pressure ◽  
Secondary Flows ◽  
System Level ◽  
Flow Profile ◽  
System Level Design ◽  
Level Design

Abstract This paper investigates the characteristics of viscous flow in the micron-scale clearances surrounding high-speed micro-rotors currently being developed for miniature energy conversion applications. Analysis and experimental results from 4 mm diameter microfabricated rotors operated above 1 million rpm are used to describe the viscous flow characteristics, and provide guidelines for system-level design. To first order, the flow is characterized as fully developed shear flow (Couette flow) across the small gaps, induced by the rotor motion. However, secondary flows are induced perpendicular to the direction of rotor motion when externally applied pressure gradients exist along the small gaps. The developing flow in the entrance region of the small gaps in this secondary flow direction impacts the shear flow profile, hence affecting the drag on the disk. The effect of other inertial forces, such as Coriolis and centrifugal forces, are investigated analytically and numerically and found to affect the shear flow profile on the fluid in the motor gap at high rotational speeds. Since viscous losses are prevelant in microsystems, appropriate modeling is necessary for system-level design.

High-Speed Digital System Design

2020 ◽  
Author(s):  
Anatoly Belous ◽  
Vitali Saladukha
Keyword(s):  
System Design ◽  
High Speed ◽  
Digital System ◽  
Digital System Design

System Design and Modeling of a Thermally Activated Reconfigurable Wing

2010 ◽  
Author(s):  
Richard Beblo ◽  
Darrel Robertson ◽  
James Joo ◽  
Brian Smyers ◽  
Gregory Reich
Keyword(s):  
Thermal Energy ◽  
High Speed ◽  
Frictional Heating ◽  
Mechanical Analysis ◽  
Design Tool ◽  
System Level ◽  
Morphing Aircraft ◽  
Thermal Actuation ◽  
Short Period ◽  
Reconfigurable Structures

Reconfigurable structures such as morphing aircraft generally require an on board energy source to function. Frictional heating during the high speed deployment of a blunt nosed low speed reconnaissance air vehicle can provide a large amount of thermal energy during a short period of time. This thermal energy can be collected, transferred, and utilized to reconfigure the deployable aircraft. Direct utilization of thermal energy has the ability to significantly decrease or eliminate the losses associated with converting thermal energy to other forms, such as electric. The following work attempts to describe possible system designs and components that can be utilized to transfer the thermal energy harvested at the nose of the aircraft during deployment to internal components for direct thermal actuation of a reconfigurable wing structure. A model of a loop heat pipe is presented and used to predict the time dependant transfer of energy. Previously reported thermal profiles of the nose of the aircraft calculated based on trajectory and mechanical analysis of the actuation mechanism are reviewed and combined with the model of the thermal transport system providing a system level feasibility investigation and design tool. The efficiency, implementation, benefits, and limitations of the direct use thermal system are discussed and compared with currently utilized systems.

High Performance Storage for Big Data Analytics and Visualization

2018 ◽  
pp. 254-275
Author(s):  
Armando Fandango ◽  
William Rivera
Keyword(s):  
Big Data ◽  
High Speed ◽  
High Performance ◽  
File System ◽  
Predictive Analytics ◽  
Big Data Analytics ◽  
File Systems ◽  
Distributed Applications ◽  
System Level ◽  
File Formats

Scientific Big Data being gathered at exascale needs to be stored, retrieved and manipulated. The storage stack for scientific Big Data includes a file system at the system level for physical organization of the data, and a file format and input/output (I/O) system at the application level for logical organization of the data; both of them of high-performance variety for exascale. The high-performance file system is designed with concurrent access, high-speed transmission and fault tolerance characteristics. High-performance file formats and I/O are designed to allow parallel and distributed applications with easy and fast access to Big Data. These specialized file formats make it easier to store and access Big Data for scientific visualization and predictive analytics. This chapter provides a brief review of the characteristics of high-performance file systems such as Lustre and GPFS, and high-performance file formats such as HDF5, NetCDF, MPI-IO, and HDFS.

Control of Rapid Transit Propulsion System Noise

1984 ◽  
Vol 106 (2) ◽  
pp. 270-277
Author(s):  
P. J. Remington ◽  
N. R. Dixon
Keyword(s):  
High Speed ◽  
Propulsion System ◽  
Laboratory Model ◽  
Rapid Transit ◽  
Blade Passage ◽  
Community Noise ◽  
System Noise ◽  
Cooling Fan ◽  
Urban Rail ◽  
Noise Impact

An extensive series of diagnostic measurements was carried out on an urban rail propulsion system of the type that was found to have the greatest community noise impact. At high speed, 3000 to 4000 rpm, the fan dominates all other sources by 10–15 dBA. At low speed, 1000 to 1500 rpm, fan, gears, and drive motors make comparable noise. A series of tests on a laboratory model of the fan/end housing of a Westinghouse 1447 propulsion motor showed that by modifying the geometry of the end housing posts and reducing the diameter of the cooling fan, the tone at the blade passage frequency was virtually eliminated. In addition, the overall noise was reduced by over 10 dBA while the same airflow was maintained through the fan. When these treatments were applied to the motor itself, it was possible to maintain the same airflow as in the unmodified motor by redesigning the grill over the inlet at the commutator end of the motor. Noise reductions, however, were not as significant as in the laboratory model. Although the blade passage tone was virtually eliminated, overall noise reduction was in the 3 to 6 dBA range, depending on the combination of treatments used.

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