scholarly journals A High Speed Particle Phase Discriminator (PPD-HS) for the classification of airborne particles, as tested in a continuous flow diffusion chamber

2019 ◽  
Author(s):  
Fabian Mahrt ◽  
Jörg Wieder ◽  
Remo Dietlicher ◽  
Helen R. Smith ◽  
Chris Stopford ◽  
...  
Keyword(s):  
Particle Shape ◽  
Continuous Flow ◽  
High Speed ◽  
Scattered Light ◽  
Diffusion Chamber ◽  
Ice Crystals ◽  
Supervised Machine Learning ◽  
Particle Phase ◽  
New Instrument ◽  
Phase Discriminator

Abstract. A new instrument, the High Speed Particle Phase Discriminator (PPD-HS) developed at the University of Hertfordshire, for sizing individual cloud hydrometeors and determining their phase is described herein. PPD-HS performs an in-situ analysis of the spatial intensity distribution of near forward scattered light for individual hydrometeors yielding shape properties. Discrimination of spherical and aspherical particles is based on an analysis of the symmetry of the recorded scattering patterns. Scattering patterns are collected onto two linear detector arrays, reducing the complete 2D scattering pattern to scattered light intensities captured onto two linear, one dimensional strips of light sensitive pixels. Using this reduced scattering information, we calculate symmetry indicators that are used for particle shape and ultimately phase analysis. This reduction of information allows for detection rates of a few hundred particles per second. Here, we present a comprehensive analysis of instrument performance using both spherical and aspherical particles, generated in a well-controlled laboratory setting using a Vibrating Orifice Aerosol Generator (VOAG) and covering a size range of approximately 3–32 micron. We use supervised machine learning to train a random forest model on the VOAG data sets that can be used to classify any particles detected by PPD-HS. Classification results show that the PPD-HS can successfully discriminate between spherical and aspherical particles, with misclassification below 5 % for diameters > 3 micro meter. This phase discrimination method is subsequently applied to classify simulated cloud particles produced in a continuous flow diffusion chamber setup. We report observations of small, near-spherical ice crystals at early stages of the ice nucleation experiments, where shape analysis fails to correctly determine the particle phase. Nevertheless, in case of simultaneous presence of cloud droplets and ice crystals, the introduced particle shape indicators allow for a clear distinction between these two classes independent of optical particle size. We conclude that PPD-HS constitutes a powerful new instrument to size and discriminate phase of cloud hydrometeors and thus study microphysical properties of mixed-phase clouds, that represent a major source of uncertainty in aerosol indirect effect for future climate projections.

scholarly journals A high-speed particle phase discriminator (PPD-HS) for the classification of airborne particles, as tested in a continuous flow diffusion chamber

2019 ◽  
Vol 12 (6) ◽  
pp. 3183-3208 ◽  
Author(s):  
Fabian Mahrt ◽  
Jörg Wieder ◽  
Remo Dietlicher ◽  
Helen R. Smith ◽  
Chris Stopford ◽  
...  
Keyword(s):  
Particle Shape ◽  
Continuous Flow ◽  
High Speed ◽  
Scattered Light ◽  
Diffusion Chamber ◽  
Ice Crystals ◽  
Supervised Machine Learning ◽  
Particle Phase ◽  
New Instrument ◽  
Phase Discriminator

Abstract. A new instrument, the High-speed Particle Phase Discriminator (PPD-HS), developed at the University of Hertfordshire, for sizing individual cloud hydrometeors and determining their phase is described herein. PPD-HS performs an in situ analysis of the spatial intensity distribution of near-forward scattered light for individual hydrometeors yielding shape properties. Discrimination of spherical and aspherical particles is based on an analysis of the symmetry of the recorded scattering patterns. Scattering patterns are collected onto two linear detector arrays, reducing the complete 2-D scattering pattern to scattered light intensities captured onto two linear, one-dimensional strips of light sensitive pixels. Using this reduced scattering information, we calculate symmetry indicators that are used for particle shape and ultimately phase analysis. This reduction of information allows for detection rates of a few hundred particles per second. Here, we present a comprehensive analysis of instrument performance using both spherical and aspherical particles generated in a well-controlled laboratory setting using a vibrating orifice aerosol generator (VOAG) and covering a size range of approximately 3–32 µm. We use supervised machine learning to train a random forest model on the VOAG data sets that can be used to classify any particles detected by PPD-HS. Classification results show that the PPD-HS can successfully discriminate between spherical and aspherical particles, with misclassification below 5 % for diameters >3 µm. This phase discrimination method is subsequently applied to classify simulated cloud particles produced in a continuous flow diffusion chamber setup. We report observations of small, near-spherical ice crystals at early stages of the ice nucleation experiments, where shape analysis fails to correctly determine the particle phase. Nevertheless, in the case of simultaneous presence of cloud droplets and ice crystals, the introduced particle shape indicators allow for a clear distinction between these two classes, independent of optical particle size. From our laboratory experiments we conclude that PPD-HS constitutes a powerful new instrument to size and discriminate the phase of cloud hydrometeors. The working principle of PPD-HS forms a basis for future instruments to study microphysical properties of atmospheric mixed-phase clouds that represent a major source of uncertainty in aerosol-indirect effect for future climate projections.

scholarly journals Development of Real-Time Time Gated Digital (TGD) OFDR Method and Its Performance Verification

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4865
Author(s):  
Kinzo Kishida ◽  
Artur Guzik ◽  
Ken’ichi Nishiguchi ◽  
Che-Hsien Li ◽  
Daiji Azuma ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Fibers ◽  
High Speed ◽  
Oil And Gas ◽  
Scattered Light ◽  
Oil And Gas Industry ◽  
High Signal ◽  
Chirp Pulse ◽  
Sound Waves ◽  
Industry Applications

Distributed acoustic sensing (DAS) in optical fibers detect dynamic strains or sound waves by measuring the phase or amplitude changes of the scattered light. This contrasts with other distributed (and more conventional) methods, such as distributed temperature (DTS) or strain (DSS), which measure quasi-static physical quantities, such as intensity spectrum of the scattered light. DAS is attracting considerable attention as it complements the conventional distributed measurements. To implement DAS in commercial applications, it is necessary to ensure a sufficiently high signal-noise ratio (SNR) for scattered light detection, suppress its deterioration along the sensing fiber, achieve lower noise floor for weak signals and, moreover, perform high-speed processing within milliseconds (or sometimes even less). In this paper, we present a new, real-time DAS, realized by using the time gated digital-optical frequency domain reflectometry (TGD-OFDR) method, in which the chirp pulse is divided into overlapping bands and assembled after digital decoding. The developed prototype NBX-S4000 generates a chirp signal with a pulse duration of 2 μs and uses a frequency sweep of 100 MHz at a repeating frequency of up to 5 kHz. It allows one to detect sound waves at an 80 km fiber distance range with spatial resolution better than a theoretically calculated value of 2.8 m in real time. The developed prototype was tested in the field in various applications, from earthquake detection and submarine cable sensing to oil and gas industry applications. All obtained results confirmed effectiveness of the method and performance, surpassing, in conventional SM fiber, other commercially available interrogators.

Investigating particle phase velocity in a 3D spouted bed by a novel fiber high speed photography method

2013 ◽  
Author(s):  
Long Qian ◽  
Yong Lu ◽  
Wenqi Zhong ◽  
Xi Chen ◽  
Bing Ren ◽  
...  
Keyword(s):  
Phase Velocity ◽  
High Speed ◽  
High Speed Photography ◽  
Particle Phase ◽  
Spouted Bed ◽  
Photography Method

Fourier Transform Infrared Spectrophotometer for Transmittance and Diffuse Reflectance Measurements

1976 ◽  
Vol 30 (6) ◽  
pp. 593-601 ◽  
Author(s):  
R. R. Willey
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Diffuse Reflectance ◽  
Storage System ◽  
Fourier Transform Infrared ◽  
Single Beam ◽  
Double Beam ◽  
New Instrument ◽  
Measurement Mode ◽  
Infrared Spectrophotometer

This paper describes a new Fourier transform infrared spectrophotometer with the capability to measure diffuse reflectance (DR) from 5000 to 500 cm−1 (2 to 20 µm) in addition to the normal transmittance measurements. The instrument has a true simultaneous double beam measurement mode and a high speed single beam mode. The system also takes advantage of many data manipulation and display features due to the built-in computer and 2.5 million word storage system. One of the objectives of this work was to produce a practical instrument which includes the DR capability; another was to introduce the qualitative and quantitative measurements of DR in the infrared to the analytical community. DR has been commonly available in the visible and near ir spectrum, but until this new instrument, has not been available in the ir. A brief survey of the background and history of DR and emittance measurements in the ir is given. The design details and operation of the instrument are generally examined. Brief examples are provided for a few transmittance, trace analysis, and microsampling applications, and a variety of DR results are shown. The addition of diffuse reflectance as a tool in the infrared opens new avenues for investigation and application in many fields.

High-speed electro-fusion and electro-transfection of plant protoplasts by a continuous flow electro-manipulator

1988 ◽  
Vol 7 (3) ◽  
pp. 153-157 ◽  
Author(s):  
T. Hibi ◽  
H. Kano ◽  
M. Sugiura ◽  
T. Kazami ◽  
S. Kimura
Keyword(s):  
Continuous Flow ◽  
High Speed ◽  
Plant Protoplasts

Chemical and Clinical Evaluation of the Continuous-flow Analyzer "SMAC"

1974 ◽  
Vol 20 (8) ◽  
pp. 1062-1070 ◽  
Author(s):  
Morton K Schwartz ◽  
Victor G Bethune ◽  
Martin Fleisher ◽  
Gina Pennacchia ◽  
Celia J Menendez-Botet ◽  
...  
Keyword(s):  
Continuous Flow ◽  
High Speed ◽  
Total Bilirubin ◽  
Carbon Dioxide Content ◽  
Protein Matrix ◽  
Sodium Potassium ◽  
Calcium Phosphorus ◽  
Matrix Reference Material ◽  
Computer Controlled ◽  
Speed Computer

Abstract "SMAC" (Sequential Multiple Analyzer plus Computer) is a high-speed computer-controlled multitest analyzer. A 20-channel prototype SMAC (glucose, urea nitrogen, creatinine, carbon dioxide content, total bilirubin, calcium, phosphorus, cholesterol, iron, uric acid, chloride, sodium, potassium, total protein, albumin, creatine kinase, alkaline phosphatase, lactate dehydrogenase, and aspartate and alanine aminotransferases) has been evaluated for: (a) method precision during within-day runs and on a day-to-day basis over a period of time; (b) method linearity over a range established on a chemical basis and related to clinical requirements, with use of both aqueous standards and protein matrix reference material; and (c) correlation of SMAC values with those obtained by the methods routinely in use in our department.

scholarly journals Estimating Surface Attachment Kinetic and Growth Transition Influences on Vapor-Grown Ice Crystals

2020 ◽  
Vol 77 (7) ◽  
pp. 2393-2410
Author(s):  
Gwenore F. Pokrifka ◽  
Alfred M. Moyle ◽  
Lavender Elle Hanson ◽  
Jerry Y. Harrington
Keyword(s):  
Diffusion Chamber ◽  
Ice Crystals ◽  
Growth Theory ◽  
Growth Data ◽  
Surface Attachment ◽  
Mass Growth ◽  
Vapor Growth ◽  
Deposition Coefficient ◽  
Direct Use ◽  
Large Decline

AbstractThere are few measurements of the vapor growth of small ice crystals at temperatures below −30°C. Presented here are mass-growth measurements of heterogeneously and homogeneously frozen ice particles grown within an electrodynamic levitation diffusion chamber at temperatures between −44° and −30°C and supersaturations si between 3% and 29%. These growth data are analyzed with two methods devised to estimate the deposition coefficient α without the direct use of si. Measurements of si are typically uncertain, which has called past estimates of α into question. We find that the deposition coefficient ranges from 0.002 to unity and is scattered with temperature, as shown in prior measurements. The data collectively also show a relationship between α and si, with α rising (falling) with increasing si for homogeneously (heterogeneously) frozen ice. Analysis of the normalized mass growth rates reveals that heterogeneously frozen crystals grow near the maximum rate at low si, but show increasingly inhibited (low α) growth at high si. Additionally, 7 of the 17 homogeneously frozen crystals cannot be modeled with faceted growth theory or constant α. These cases require the growth mode to transition from efficient to inefficient in time, leading to a large decline in α. Such transitions may be, in part, responsible for the inconsistency in prior measurements of α.

Development and Evaluation of a High-Speed Continuous-Flow Analyzer

1972 ◽  
Vol 18 (9) ◽  
pp. 1013-1018
Author(s):  
M A Evenson ◽  
M A Olson
Keyword(s):  
Continuous Flow ◽  
High Speed ◽  
High Performance ◽  
Operating Characteristics ◽  
Raw Data ◽  
Automatic Computer ◽  
Carry Over ◽  
First Time

Abstract A high-speed, high-performance, continuous-flow analyzer is described that operates at two to three times the usual analysis rate without necessitating corrections of the raw data and with no decrease in accuracy or precision. At faster speeds (180-300 samples/h) inductive sample interaction (%Ii), opposite in direction to carry-over, is for the first time quantitatively measured. A correction equation for %Ii was developed, and when it is applied to raw data, the accuracy of the results are significantly improved. Operating characteristics of the high-speed analyzer are described and the desirability of automatic computer corrections is discussed for the high-speed system.

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