Shake-The-Box particle tracking with variable time-steps in flows with high velocity range (VT-STB)

We present a novel evaluation mode for Lagrangian Particle Tracking methods in general, applied to the Shake-The-Box method specifically. The aim is to attain high levels of accuracy and a removal of false (‘ghost’) tracks in flow situations, where significant amounts of particles show small relative movement with respect to each other in consecutive time-steps. An iterative approach using variable time separations is employed, which starts by tracking particles at high timeseparations, followed by an iterative reduction of time separation, while feeding the particle tracked within the previous iterations. The process allows for applying tracking parameters fine-tuned to the different flow regimes tracked within each iteration. Experimental validation was performed using a dataset on impinging jet flow, created in collaboration with the School of Mechanical Engineering of Pusan National University. Evaluation of this flow with high velocity range shows distinct advantages in reduction of ghost tracks and in tracking accuracy.

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Improving z-tracking accuracy in the two-photon single-particle tracking microscope

Applied Physics Letters ◽

10.1063/1.4932224 ◽

2015 ◽

Vol 107 (15) ◽

pp. 153701 ◽

Cited By ~ 8

Author(s):

C. Liu ◽

Y.-L. Liu ◽

E. P. Perillo ◽

N. Jiang ◽

A. K. Dunn ◽

...

Keyword(s):

Particle Tracking ◽

Single Particle ◽

Single Particle Tracking ◽

Tracking Accuracy ◽

Two Photon

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Dependence of the Coefficient of Friction on the Sliding Conditions in the High Velocity Range

Journal of Tribology ◽

10.1115/1.2833808 ◽

1999 ◽

Vol 121 (1) ◽

pp. 35-41 ◽

Cited By ~ 49

Author(s):

A. Molinari ◽

Y. Estrin ◽

S. Mercier

Keyword(s):

Coefficient Of Friction ◽

High Velocity ◽

Numerical Solutions ◽

Constitutive Relations ◽

Shear Banding ◽

Normal Pressure ◽

Adiabatic Shear ◽

Velocity Range ◽

Adiabatic Shear Banding ◽

The Coefficient Of Friction

The velocity, normal pressure, and slider size dependence of the coefficient of dry friction of metals in the range of high sliding velocities (V ≥ 1 m/s) is investigated theoretically. Failure of the adhesive junctions by adiabatic shear banding is considered as the underlying process. The concept of asperity shearing by the adiabatic shear banding mechanism represents a new approach to unlubricated high velocity friction. Analytical solutions of a coupled thermomechanical problem are given for two constitutive relations. Numerical solutions for steel-on-steel friction showing a decrease of the coefficient of friction with the sliding velocity for different normal pressures are presented. The model is considered to be adequate in the velocity range of 1–10 m/s where friction enhanced oxidation or surface melting are believed not to interfere with the asperity shearing process.

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High-velocity range and energy-loss measurements in Al, Cu, Pb, U and emulsion

Il Nuovo Cimento ◽

10.1007/bf02819680 ◽

1961 ◽

Vol 19 (S1) ◽

pp. 41-62 ◽

Cited By ~ 20

Author(s):

W. H. Barkas ◽

S. von Friesen

Keyword(s):

Energy Loss ◽

High Velocity ◽

Velocity Range

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Novel strategy for wide-range wind vector measurement using the hybrid CP/CTD heating mode and sequential measuring and correcting

PLoS ONE ◽

10.1371/journal.pone.0254256 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254256

Author(s):

Tian Wang ◽

Yunbo Shi ◽

Xiaoyu Yu ◽

Guangdong Lan ◽

Congning Liu

Keyword(s):

Wind Velocity ◽

Wind Direction ◽

High Velocity ◽

Measurement Instrument ◽

Wind Vector ◽

Velocity Range ◽

Vector Measurement ◽

Airflow Distribution ◽

Wide Range ◽

Novel Strategy

To improve the performance of wind sensors in the high velocity range, this paper proposes a wind measurement strategy for thermal wind velocity sensors that combines the constant power and constant temperature difference driving modes of the heating element. Based on the airflow distribution characteristics from fluid dynamics, sequential measurement and correction is proposed as a method of measuring wind direction. In addition, a wind velocity and direction measurement instrument was developed using the above-mentioned approaches. The test results showed that the proposed instrument can obtain large dynamic wind velocity measurements from 0 to 60 m/s. The wind velocity measurement accuracy was ±0.5 m/s in the common velocity range of 0–20 m/s and ±1 m/s in the high velocity range of 20–60 m/s. The wind direction accuracy was ±3° throughout the 360° range. The proposed approaches and instrument are not only practical but also capable of meeting the requirements of wide-range and large dynamic wind vector measurement applications.

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On the radiation tolerance of CMOS Monolithic Active Pixel Sensors with partially depleted active volume

10.21248/gups.64550 ◽

2021 ◽

Author(s):

◽

Michael Deveaux

Keyword(s):

Charged Particle ◽

Particle Tracking ◽

Radiation Detectors ◽

Heavy Ion ◽

Radiation Tolerance ◽

Tracking Accuracy ◽

Active Pixel Sensors ◽

Active Pixel ◽

Pixel Sensors ◽

Charged Particle Tracking

CMOS Monolithic Active Pixel Sensors for charged particle tracking (CPS) form are ultra-light and highly granular silicon pixel detectors suited for highly sensitive charged particle tracking. Unlike to most other silicon radiation detectors, they rely on standard CMOS technology. This cost efficient approach allows for building particularly small and thin pixels but also introduced, until recently, substantially constraints on the design of the sensors. The most important among them is the missing compatibility with the use of PMOS transistors and depleted charge collection diodes in the pixel. Traditional CPS were thus first of all suited for vertex detectors of relativistic heavy ion and particle physics experiments, which require highest tracking accuracy in combination with moderate time resolution and radiation tolerance. This work reviews the R&D on understanding and improving the radiation tolerance of traditional CPS with non- and partially depleted active medium as pioneered by the MIMOSA-series developed by the IPHC Strasbourg. It introduces the specific measurement methods used to assess the radiation tolerance of those non-standard pixels. Moreover, it discusses the major mechanisms of radiation damage and procedures for radiation hardening, which allowed to extend the radiation tolerance of the devices by more than an order of magnitude.

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1612 MHz observations of southern IRAS sources

Symposium - International Astronomical Union ◽

10.1017/s0074180900156426 ◽

1987 ◽

Vol 122 ◽

pp. 215-216

Author(s):

M. E. Dollery ◽

M. J. Gaylard ◽

R. J. Cohen

Keyword(s):

High Velocity ◽

The Other ◽

Velocity Range ◽

Low Velocity

Eight of thirty-four previously unobserved IRAS sources were found to be relatively strong 1612 MHz OH emitters. Five of these emit at 1667 MHz. Of the eight half are high velocity range, population I type stars, the other half are low velocity range, population II type stars. The pump efficiencies are in the range 0.018 ≤ e ≤ 0.163.

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Submillimeter H2O maser emission from water fountain nebulae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317010572 ◽

2017 ◽

Vol 13 (S336) ◽

pp. 369-372

Author(s):

Daniel Tafoya ◽

Wouter H. T. Vlemmings ◽

Andres F. Pérez-Sánchez

Keyword(s):

Simple Model ◽

High Velocity ◽

Kinetic Temperature ◽

Velocity Range ◽

Bipolar Outflows ◽

Maser Emission ◽

Water Maser

AbstractWe present the results of the first detection of submillimeter water maser emission toward water-fountain nebulae. Using APEX we found emission at 321.226 GHz toward two sources: IRAS 18043−2116, and IRAS 18286−0959. The submillimeter H2O masers exhibit expansion velocities larger than those of the OH masers, suggesting that these masers, similarly to the 22 GHz masers, originate in fast bipolar outflows. The 321 GHz masers in IRAS 18043−2116 and IRAS 18286−0959, which figure among the sources with the fastest H2O masers, span a velocity range similar to that of the 22 GHz masers, indicating that they probably coexist. The intensity of the submillimeter masers is comparable to the 22 GHz masers, implying that the kinetic temperature of the region where the masers originate is Tk>1000 K. We propose a simple model invoking the passage of two shocks through the same gas that creates the conditions for explaining the strong high-velocity 321 GHz masers coexisting with the 22 GHz masers in the same region.

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Variability of Water Masers in W49N: Results from Effelsberg Long-term Monitoring Programme

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317011437 ◽

2017 ◽

Vol 13 (S336) ◽

pp. 279-280 ◽

Cited By ~ 1

Author(s):

Busaba H. Kramer ◽

Karl M. Menten ◽

Alex Kraus

Keyword(s):

High Velocity ◽

Monitoring Programme ◽

Shock Propagation ◽

Velocity Range ◽

Long Term Monitoring ◽

Water Masers ◽

Term Monitoring ◽

Line Observation ◽

Better Than

AbstractWe present the results from an ongoing long-term monitoring of the 22 GHz H2O maser in W49N with the 100-m Effelsberg radio telescope from February 2014 to September 2017. The unique Effelsbergs spectral line observation capability provides a broad velocity range coverage from −500 to +500 km s−1 with a spectral resolution better than 0.1 km/s. Following the strong major outburst in W49N in late 2013, we have started a long-term monitoring programme at Effelsberg. The major outburst feature (up to 80,000 Jy at VLSR − 98 km s−1) faded away by June 2014. However, we found that the site is still active with several high velocity outbursts (both blue and redshifted). Some features appear at extremely high velocities (up to ±280 km s−1) and show rapid flux variations within a 1-2 month period. This sub-year scale variability implies that the water masers could be excited by episodic shock propagation caused by a high-velocity protostellar jet.

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