Empirical correlation property of multi-path for high-speed railways in composite propagation scenario

2015 ◽  
Author(s):  
Bei Zhang ◽  
Zhangdui Zhong ◽  
Ruisi He ◽  
Ke Guan ◽  
Jianwen Ding ◽  
...  
Keyword(s):  
High Speed ◽  
Empirical Correlation ◽  
Correlation Property ◽  
Propagation Scenario

An Empirical Correlation for Maximum Penetration Depth of a Particle Impacting on a Free Surface at its Critical Velocity Condition

2011 ◽  
Vol 361-363 ◽  
pp. 320-323 ◽  
Author(s):  
Dong Mei Liu ◽  
Geoffrey Michael Evans ◽  
Qing Lin He
Keyword(s):  
Penetration Depth ◽  
Critical Condition ◽  
High Speed ◽  
Least Squares Method ◽  
Density Ratio ◽  
Video Camera ◽  
Empirical Correlation ◽  
Liquid Density ◽  
Maximum Penetration Depth ◽  
Maximum Penetration

Film flotation is a process which consumes much lower energy than mechanical cells. The extended film flotation technique is to separate mineral mixtures by different critical impact velocities. In this study the maximum penetration depth of a particle at its critical condition was investigated experimentally and theoretically. Experiments were performed using spherical glass beads of different diameters and hydrophobicities and different liquids. The penetration depth at critical condition was recorded and measured using high speed video camera. Buckingham’s PI theorem was applied to analyse the dimensionless groups, and then an empirical correlation for penetration depth was obtained by partial least squares method. It was found that the prediction results of the empirical equation were in good agreement with the measurements. Also, the influence factors were analysed. It was noticed that the hydrophobicities of particle and particle-liquid density ratio had most significant effects on the penetration depth.

Experimental Investigation Into Creep Buckling of a Stainless Steel Plate Column Under Axial Compression at Extremely High Temperatures

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Byeongnam Jo ◽  
Koji Okamoto
Keyword(s):  
Stainless Steel ◽  
High Temperatures ◽  
High Speed ◽  
Failure Time ◽  
Empirical Correlation ◽  
Buckling Behavior ◽  
Creep Buckling ◽  
Steel Column ◽  
Stainless Steel Column ◽  
Buckling Failure

This study aims to investigate the creep buckling behavior of a stainless steel column under axial compressive loading at extremely high temperatures. Creep buckling failure time of a slender column with a rectangular cross section was experimentally measured under three different temperature conditions, namely, 800, 900, and 1000 °C. At each temperature, axial compressive loads with magnitudes ranging between 15% and 80% of the buckling loads were applied to the top of the column, and the creep buckling failure time was measured to examine its relationship with the compressive load. The stainless steel column was found to fail within a relatively short time compared to that of creep deformation under tensile loading. An increase in the temperature of the column was found to accelerate creep buckling failure. The in-plane and out-of-plane column displacements, which respectively, corresponded to the axial and lateral displacements, were monitored during the entire experiment. The creep buckling behavior of the column was also visualized by a high-speed camera. Based on the Larson–Miller parameters (LMP) determined from the experimental results, an empirical correlation for predicting the creep buckling failure time was developed. Another empirical correlation for predicting the creep buckling failure time based on the lateral deflection rate was also derived.

Experimental Spray Structure and Combustion of a Linearly-Arranged 5-Swirler Array

2015 ◽  
Author(s):  
Yi-Huan Kao ◽  
Michael Denton ◽  
Xionghui Wang ◽  
San-Mou Jeng ◽  
Ming-Chia Lai
Keyword(s):  
Reynolds Number ◽  
Air Temperature ◽  
High Speed ◽  
Swirling Flow ◽  
Empirical Correlation ◽  
Unexpected Result ◽  
Ignition Process ◽  
Flame Spreading ◽  
Spray Structure ◽  
Flow Interactions

The presented work focuses on the experimental spray structure and the combustion of a linearly-arranged 5-swirler array. The aerodynamics and spray characteristics of a non-reacting single swirler are reported first as a baseline, followed by those of a 5-swirler array to investigate the effect of swirling flow interactions on aerodynamics and combustion. For the baseline single swirler, the smaller droplets follow the air flow more closely and further dispersed away at the exit of swirler. Thus, the mean diameter of droplet increases with the flow developing further downstream. However, in the central portion of a 5-swirler array, the droplet size remains similar. It is attributed to that swirling flow interactions might provide better air/fuel mixing and the additional shear stress to break up droplet continuously and is evident by the higher turbulent intensity in the aerodynamic measurement. Due to the influence of gas phase, the distribution of liquid phase in center toroidal recirculation zone (CTRZ) is non-uniform in a 5-swirler array. The center swirler of a 5-swirler array features a larger CTRZ which is accompanied by two smaller CTRZs from its neighbors. The flame anchored by the center swirler of a 5-swirler array is richer than the other two neighboring flames when the inter-swirler spacing is 2D, where D is the diameter of swirler exit diameter. However, when the inter-swirler spacing is increased to 2.5D, all swirlers feature a similar flame, which is different from what is expected from non-reacting flow studies reported previously. The unexpected result should be attributed to the difference in swirling strength between non-reacting and reacting flows. Moreover, the high speed imaging is employed to investigate the flame spreading during ignition process for a 5-swirler array. The high-speed movies show that the directional mechanism of flame spreading along lateral direction remains basically the same and is independent of the investigated test parameters including: two inter-swirler spacings, five fuel flow rates, five air pressure drops across swirlers, and five upstream air temperatures. An empirical correlation incorporating normalized inter-swirler spacing, air/fuel ratio, Reynolds number, and normalized air temperature is proposed and validated through a normalization procedure within around ± 10% error. The increase of Reynolds number and normalized air temperature has favorable impact on the flame spreading, which is stated by the empirical correlation.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

An atomic-resolution microscope study of Al contracts on GaAs

1986 ◽  
Vol 44 ◽  
pp. 726-727
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
High Speed ◽  
Schottky Contacts ◽  
Detailed Knowledge ◽  
The Past ◽  
Semiconductor Interfaces ◽  
Deposited Metal ◽  
Microwave Applications ◽  
Free Interfaces ◽  
Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

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