Characterization of Pressure Waves in HCCI Combustion

2002 ◽  
Author(s):  
J. A. Eng
Keyword(s):  
Pressure Waves ◽  
Hcci Combustion

A Comparison of Mechanical Wind Filters for Infrasound Sensor Noise Reduction

2021 ◽  
Author(s):  
Sarah McComas ◽  
Chris Hayward ◽  
Stephen Arrowsmith ◽  
Brian Stump ◽  
Mihan H. McKenna Taylor
Keyword(s):  
Data Analysis ◽  
Atmospheric Turbulence ◽  
Acoustic Pressure ◽  
Urban Setting ◽  
Pressure Waves ◽  
Earth Atmosphere ◽  
Acoustic Spectrum ◽  
Single Sensor ◽  
Insight Into

Abstract Infrasound sensors record the ambient acoustic field that contains not only signals of interest but also noise and clutter. Noise is defined as atmospheric turbulence that is incoherent over the distances of meters, whereas, signals of interest and clutter are acoustic pressure waves that are coherent over 10s of meters to 100s of kilometers. There is a growing interest in monitoring sources that extend across the acoustic spectrum from infrasound (below 20 Hz) into the low-end audible acoustic (20–1000 Hz). Monitoring of these extended band signals with a single sensor is made possible with the development of contemporary infrasound sensors, such as Hyperion IFS-3000 with a flat response from 0.01 to 1000 Hz. Combining infrasound sensors with seismometers provides opportunity to better assess noise contributions for both sensor types and improve characterization of sources that occur close to the solid earth–atmosphere boundary. Because sensors are installed to target these broadband acoustic sources, considerations need to be made when selecting a mechanical wind filter to mitigate the noise, while minimizing the impacts to the signals of interest across these frequency ranges. Motivated by these opportunities, this article compares traditional infrasound wind filter designs, that is, porous hoses rosettes and domes, in an urban setting for frequencies 0.01–45 Hz. Data analysis compares the filters, in terms of their response to noise and signals with direct comparisons of wind filters, as a function of frequency. The quantification of performance of these filters in an urban setting provides insight into their effects on detection of sources of interest in this environment.

Characterization of the Pressure Wave Emitted From Implosion of Submerged Cylindrical Shell Structures

2012 ◽  
Author(s):  
Michael D. Shields ◽  
Pawel Woelke ◽  
Najib N. Abboud
Keyword(s):  
Pressure Wave ◽  
Pressure Pulse ◽  
Peak Pressure ◽  
Structural Parameters ◽  
Shell Structures ◽  
High Fidelity ◽  
Pressure Waves ◽  
Structural Configurations ◽  
The Impact

Buckling of submerged cylindrical shells is a sudden and rapid implosion which emits a high pressure pulse that may be damaging to nearby structures. The characteristics of this pressure pulse are dictated by various parameters defining the shell structure such as the length to diameter ratio, shell thickness, material, and the existence and configuration of internal stiffeners. This study examines, through the use of high fidelity coupled fluid-structure finite element computations, the impact of various structural parameters on the resulting pressure wave emanating from the implosion. The results demonstrate that certain structural configurations produce pressure waves with higher peak pressure and impulse thereby enhancing the potential for damage to nearby structures.

The Origin of Pressure Waves in High Load HCCI Combustion: A High-Speed Video Analysis

2011 ◽  
Vol 183 (11) ◽  
pp. 1266-1281 ◽  
Author(s):  
Daniel Dahl ◽  
Mats Andersson ◽  
Ingemar Denbratt
Keyword(s):  
Video Analysis ◽  
High Speed ◽  
High Load ◽  
Pressure Waves ◽  
High Speed Video ◽  
Hcci Combustion

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

2013 ◽  
Vol 6 (1) ◽  
pp. 553-568 ◽  
Author(s):  
James P. Szybist ◽  
K. Dean Edwards ◽  
Matthew Foster ◽  
Keith Confer ◽  
Wayne Moore
Keyword(s):  
High Load ◽  
Engine Control ◽  
Hcci Combustion ◽  
Load Limit ◽  
Control Authority

scholarly journals Characterization of Simultaneous Pressure Waves as Biomarkers for Colonic Motility Assessed by High-Resolution Colonic Manometry

2018 ◽  
Vol 9 ◽  
Author(s):  
Ji-Hong Chen ◽  
Sean P. Parsons ◽  
Mitra Shokrollahi ◽  
Andrew Wan ◽  
Alexander D. Vincent ◽  
...  
Keyword(s):  
High Resolution ◽  
Colonic Motility ◽  
Pressure Waves ◽  
Colonic Manometry

scholarly journals Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Mischa Schmidt ◽  
Ulf Kahlert ◽  
Johanna Wessolleck ◽  
Donata Maciaczyk ◽  
Benjamin Merkt ◽  
...  
Keyword(s):  
High Amplitude ◽  
Living Cells ◽  
Pressure Waves ◽  
The Impact

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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