In Situ Visualizing Oxidase-Mimicking Activity of Single MnOOH Nanotubes with Mie Scattering-Based Absorption Microscopy

2021 ◽  
Vol 60 (7) ◽  
pp. 5264-5270
Author(s):  
Ling Yu ◽  
Hua Li ◽  
Wei Huang ◽  
Haili Yu ◽  
Yi He
Keyword(s):  
Mie Scattering

scholarly journals Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data

2019 ◽  
Vol 12 (6) ◽  
pp. 3067-3079
Author(s):  
Sebastian J. O'Shea ◽  
Jonathan Crosier ◽  
James Dorsey ◽  
Waldemar Schledewitz ◽  
Ian Crawford ◽  
...  
Keyword(s):  
Climate Models ◽  
Synthetic Data ◽  
Mie Scattering ◽  
Sample Volume ◽  
Research Aircraft ◽  
Order Of Magnitude ◽  
Ambient Data ◽  
In Situ Observations ◽  
Synthetic Datasets

Abstract. In situ observations from research aircraft and instrumented ground sites are important contributions to developing our collective understanding of clouds and are used to inform and validate numerical weather and climate models. Unfortunately, biases in these datasets may be present, which can limit their value. In this paper, we discuss artefacts which may bias data from a widely used family of instrumentation in the field of cloud physics, optical array probes (OAPs). Using laboratory and synthetic datasets, we demonstrate how greyscale analysis can be used to filter data, constraining the sample volume of the OAP and improving data quality, particularly at small sizes where OAP data are considered unreliable. We apply the new methodology to ambient data from two contrasting case studies: one warm cloud and one cirrus cloud. In both cases the new methodology reduces the concentration of small particles (<60 µm) by approximately an order of magnitude. This significantly improves agreement with a Mie-scattering spectrometer for the liquid case and with a holographic imaging probe for the cirrus case. Based on these results, we make specific recommendations to instrument manufacturers, instrument operators and data processors about the optimal use of greyscale OAPs. The data from monoscale OAPs are unreliable and should not be used for particle diameters below approximately 100 µm.

Spectrometric System for Characterizing Drop and Powder Trajectories and Chemistry in Reactive Flows

2002 ◽  
Vol 56 (10) ◽  
pp. 1345-1353 ◽  
Author(s):  
Jerry C. Cabalo ◽  
John Schmidt ◽  
Jost O. L. Wendt ◽  
Alexander Scheeline
Keyword(s):  
Flow System ◽  
Axisymmetric Flow ◽  
Mie Scattering ◽  
Field Of View ◽  
Thermal Reactor ◽  
Worst Case ◽  
Full Field ◽  
Spectrometric System ◽  
Nominally Laminar Flow

An instrument for emission, fluorescence, and scattering diagnostics of a 22 kW gas/air thermal reactor is described. Z-pair parabolic mirrors provide diffraction-limited imaging in field center, with worst-case blur over a 12.8 mm field of view having a radius of 0.044 mm rms. Either full-field filtered or transverse line dispersed viewing can occur simultaneously. Dispersion is achieved using a 2-m spectrograph f-matched to the feed optics. Examples of data show non-axisymmetric flow in a nominally laminar flow system, drop shapes in situ, and Mie scattering from soot.

scholarly journals Development and validation of a CCD-laser aerosol detective system for measuring the ambient aerosol phase function

2017 ◽  
Author(s):  
Yuxuan Bian ◽  
Chunsheng Zhao ◽  
Wanyun Xu ◽  
Gang Zhao ◽  
Jiangchuan Tao ◽  
...  
Keyword(s):  
Phase Function ◽  
Radiative Forcing ◽  
Mie Scattering ◽  
Angular Range ◽  
Ambient Aerosols ◽  
Detection Range ◽  
Charge Coupled Device ◽  
Angular Scattering ◽  
Development And Validation

Abstract. Aerosol phase function represents the angular scattering property of aerosols, which is crucial for understanding the climate effects of aerosols that have been identified as one of the largest uncertainties in the evaluation of radiative forcing. So far, there is a lack of instruments to measure the aerosol phase function directly and accurately in laboratory studies and in-situ measurements. A portable instrument with high angular range and resolution has been developed for the measurement of the phase function of ambient aerosols in this study. The charge-coupled device-laser aerosol detective system (CCD-LADS), which measures the aerosol phase function both across a relatively wide angular range of 10°–170° and at a high resolution of 0.1°. The system includes a continuous laser, two charge-coupled device cameras and the corresponding fisheye lenses. The CCD-LADS was validated by both a laboratory study and a field measurement. The comparison between the aerosol phase function retrieved from CCD-LADS and Mie-scattering model shows good agreement. Compared with the TSI polar nephelometer, CCD-LADS has the advantages of wider detection range and better stability.

scholarly journals Revisiting particle sizing using grayscale optical array probes evaluation using laboratory experiments and synthetic data

2019 ◽  
Author(s):  
Sebastian J. O'Shea ◽  
Jonathan Crosier ◽  
James Dorsey ◽  
Waldemar Schledewitz ◽  
Ian Crawford ◽  
...  
Keyword(s):  
Climate Models ◽  
Synthetic Data ◽  
Mie Scattering ◽  
Sample Volume ◽  
Research Aircraft ◽  
Order Of Magnitude ◽  
Ambient Data ◽  
In Situ Observations ◽  
Synthetic Datasets

Abstract. In-situ observations from research aircraft and instrumented ground sites are important contributions to developing our collective understanding of clouds, and are used to inform and validate numerical weather and climate models. Unfortunately, biases in these datasets may be present, which can limit their value. In this paper, we discuss artefacts which may bias data from a widely used family of instrumentation in the field of cloud physics, Optical Array Probes (OAPs). Using laboratory and synthetic datasets, we demonstrate how greyscale analysis can be used to filter data, constraining the sample volume of the OAP, and improving data quality particularly at small sizes where OAP data are considered unreliable. We apply the new methodology to ambient data from two contrasting case studies: one warm cloud and one cirrus cloud. In both cases the new methodology reduces the concentration of small particles (< 60 µm) by approximately an order of magnitude. This significantly improves agreement with a Mie scattering spectrometer for the liquid case and with a holographic imaging probe for the cirrus case. Based on these results, we make specific recommendations to instrument manufacturers, instrument operators, and data processors about the optimal use of greyscale OAP’s. We also raise the issue of bias in OAP’s which have no greyscale capability.

scholarly journals A new experimental approach to study the hygroscopic and optical properties of aerosols: application to ammonium sulfate particles

2014 ◽  
Vol 7 (1) ◽  
pp. 183-197 ◽  
Author(s):  
C. Denjean ◽  
P. Formenti ◽  
B. Picquet-Varrault ◽  
Y. Katrib ◽  
E. Pangui ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Distribution ◽  
Ammonium Sulfate ◽  
Residence Time ◽  
Mie Scattering ◽  
Continuous Increase ◽  
Continuous Growth ◽  
Hygroscopic Properties

Abstract. A new methodology for the determination of the changes due to hygroscopic growth with relative humidity of the number size distribution and optical properties of polydispersed aerosols is described. This method uses the simulation chamber CESAM where the hygroscopic properties of polydispersed aerosol particles can be investigated in situ by exposing them to RH ranging from 0 to 100% for approximately 1 h. In situ humidification is used to provide simultaneous information on the RH-dependence of the particle size and the corresponding scattering coefficient (σscat), and that for the entire size distribution. Optical closure studies, based on integrated nephelometer and aethalometer measurements, Mie scattering calculations and measured particle size distributions, can therefore be performed to yield derived parameters such as the complex refractive index (CRI) at λ = 525 nm. The CRI can also be retrieved in the visible spectrum by combining differential mobility analyzer (DMA) and white light aerosol spectrometer (Palas Welas®) measurements. We have applied this methodology to ammonium sulfate particles, which have well known optical and hygroscopic properties. The CRI obtained from the two methods (1.54–1.57) compared favourably to each other and are also in reasonable agreement with the literature values. The particle's growth was compared to values obtained for one selected size of particles (150 nm) with a H-TDMA and the effect of the residence time for particles humidification was investigated. When the humidification was performed in the chamber for a few minutes, a continuous increase of the ammonium sulfate particle's size and σscat was observed from RH values as low as 30% RH. Comparison of the measured and modelled values based on Köhler and Mie theories shows that layers of water are adsorbed on ammonium sulfate particles below the deliquescence point. In contradiction, the particle's growth reported with H-TDMAs showed a prompt deliquescence of ammonium sulfate particles with no continuous growth in size at low RH. These findings highlight the need to allow sufficient time for particle-water vapour equilibrium in investigating the aerosols hygroscopic properties. H-TDMA instruments induce limited residence time for humidification and seem to be insufficient for water adsorption on ammonium sulfate particles.

scholarly journals Silver/poly(N-vinyl-2-pyrrolidone) nanocomposites obtained by the electrochemical synthesis

2011 ◽  
Vol 65 (6) ◽  
pp. 687-696 ◽  
Author(s):  
Zeljka Jovanovic ◽  
Aleksandra Radosavljevic ◽  
Zorica Kacarevic-Popovic ◽  
Vesna Miskovic-Stankovic
Keyword(s):  
Applied Voltage ◽  
Ag Nanoparticles ◽  
Silver Ions ◽  
Mie Scattering ◽  
Visible Spectroscopy ◽  
Vis Spectroscopy ◽  
Theoretical Predictions ◽  
Implementation Time ◽  
Uv Visible

Silver/poly(N-vinyl-2-pyrrolidone) (Ag/PVP) nanocomposites were obtained by electrochemical reduction of Ag+ ions at a constant voltage, by the in situ synthesis of silver nanoparticles inside poly(N-vinyl-2-pyrrolidone) matrix, previously crosslinked by ?-irradiation. Optimal values of synthesis parameters were investigated: the composition of the solution for swelling of PVP hydrogel, implementation time and applied voltage. Ag/PVP nanocomposites were characterized by UV-visible spectroscopy, and IR spectroscopy. UV-visible spectroscopy results shown that the reduction of silver ions was more efficient when the more conductive solution for swelling of PVP hydrogel was used, i.e. the solution containing 3.9 mM AgNO3 with 0.1 M KNO3. Also, it was shown that the concentration of the reduced silver increases with the increase in implementation time and applied voltage, up to the values of 4 min, and 200 V, respectively. The Ag nanoparticle size was estimated to be 25 nm, by comparison of the experimental results of UV-vis spectroscopy with the theoretical predictions obtained by the calculations in ?MiePlot v.3.4? computer program, having the algorithm based on Mie scattering from a sphere. The results of FTIR spectroscopy have shown that Ag nanoparticles are mainly bonded to PVP by coordination bondages between Ag nanoparticles and N from the pyrrolidone ring of PVP.

scholarly journals The Retrieval of Ice-Cloud Properties from Cloud Radar and Lidar Synergy

2005 ◽  
Vol 44 (6) ◽  
pp. 860-875 ◽  
Author(s):  
Claire Tinel ◽  
Jacques Testud ◽  
Jacques Pelon ◽  
Robin J. Hogan ◽  
Alain Protat ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Radar Data ◽  
Mie Scattering ◽  
In Situ Measurements ◽  
Physical Parameters ◽  
Backscatter Coefficient ◽  
Blind Test ◽  
Cloud Radar ◽  
Microphysical Properties

Abstract Clouds are an important component of the earth’s climate system. A better description of their microphysical properties is needed to improve radiative transfer calculations. In the framework of the Earth, Clouds, Aerosols, and Radiation Explorer (EarthCARE) mission preparation, the radar–lidar (RALI) airborne system, developed at L’Institut Pierre Simon Laplace (France), can be used as an airborne demonstrator. This paper presents an original method that combines cloud radar (94–95 GHz) and lidar data to derive the radiative and microphysical properties of clouds. It combines the apparent backscatter reflectivity from the radar and the apparent backscatter coefficient from the lidar. The principle of this algorithm relies on the use of a relationship between the extinction coefficient and the radar specific attenuation, derived from airborne microphysical data and Mie scattering calculations. To solve radar and lidar equations in the cloud region where signals can be obtained from both instruments, the extinction coefficients at some reference range z0 must be known. Because the algorithms are stable for inversion performed from range z0 toward the emitter, z0 is chosen at the farther cloud boundary as observed by the lidar. Then, making an assumption of a relationship between extinction coefficient and backscattering coefficient, the whole extinction coefficient, the apparent reflectivity, cloud physical parameters, the effective radius, and ice water content profiles are derived. This algorithm is applied to a blind test for downward-looking instruments where the original profiles are derived from in situ measurements. It is also applied to real lidar and radar data, obtained during the 1998 Cloud Lidar and Radar Experiment (CLARE’98) field project when a prototype airborne RALI system was flown pointing at nadir. The results from the synergetic algorithm agree reasonably well with the in situ measurements.

Observations Pertaining to Precipitation within the Northeast Pacific Stratocumulus-to-Cumulus Transition

2019 ◽  
Vol 148 (3) ◽  
pp. 1251-1273
Author(s):  
Mampi Sarkar ◽  
Paquita Zuidema ◽  
Bruce Albrecht ◽  
Virendra Ghate ◽  
Jorgen Jensen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Initial Conditions ◽  
Mixed Boundary ◽  
Cloud Droplet ◽  
Mie Scattering ◽  
Cumulus Clouds ◽  
Different Depths ◽  
High Precipitation

Abstract Three genuine stratocumulus-to-cumulus transitions sampled during the Cloud System Evolution over the Trades (CSET) campaign are documented. The focus is on Lagrangian evolution of in situ precipitation, thought to exceed radar/lidar retrieved values because of Mie scattering. Two of the three initial stratocumulus cases are pristine [cloud droplet number concentrations (Nd) of ~22 cm−3] but occupied boundary layers of different depths, while the third is polluted (Nd ~ 225 cm−3). Hourly satellite-derived cloud fraction along Lagrangian trajectories indicate that more quickly deepening boundary layers tend to transition faster, into more intense but more occasional precipitation. These transitions begin either in the morning or late afternoon, suggesting that preceding night processes can precondition or delay the inevitable transition. The precipitation shifts toward larger drop sizes throughout the transition as the boundary layers deepen, with aerosol concentrations only diminishing in two of the three cases. Ultraclean (Nd &lt; 1 cm−3) cumulus clouds evolved from pristine stratocumulus cloud with unusually high precipitation rates occupying a shallow, well-mixed boundary layer. Results from a simple one-dimensional evaporation model and from radar/lidar retrievals suggest subcloud evaporation likely increases throughout the transition. This, coupled with larger drop sizes capable of lowering the latent cooling profile, facilitates the transition to more surface-driven convection. The coassociation between boundary layer depth and precipitation does not provide definitive conclusions on the isolated effect of precipitation on the pace of the transition. Differences between the initial conditions of the three examples provide opportunities for further modeling studies.

In situ size measurement of a magnetically trapped single superconducting microparticle by Mie scattering

2021 ◽  
Author(s):  
Masato Takamune ◽  
Shota Sasaki ◽  
Daisei Kondo ◽  
Jun Naoi ◽  
Mitsutaka Kumakura ◽  
...  
Keyword(s):  
Scattering Theory ◽  
Incident Light ◽  
Mie Scattering ◽  
Angular Distributions ◽  
Refractive Indices ◽  
Size Measurement ◽  
Magnetically Trapped ◽  
Quadrupole Magnetic Field ◽  
Mie Scattering Theory

Abstract Light scattering by a single superconducting microparticle trapped in a quadrupole magnetic field has been observed. The angular distributions of the scattering light were recored for multiple colors of incident light, and were well reproduced by using the Mie scattering theory with the refractive indices for normal conducting metals. This analysis provides us the radius of the trapped particle.

scholarly journals Optical studies of noctilucent clouds in the extreme ultraviolet

2008 ◽  
Vol 26 (5) ◽  
pp. 1109-1119 ◽  
Author(s):  
J. Hedin ◽  
J. Gumbel ◽  
M. Khaplanov ◽  
G. Witt ◽  
J. Stegman
Keyword(s):  
Particle Size ◽  
Extreme Ultraviolet ◽  
Mie Scattering ◽  
Optical Measurements ◽  
Noctilucent Clouds ◽  
Particle Size Distributions ◽  
Cloud Particle ◽  
Variable Environment ◽  
Sounding Rockets

Abstract. In order to better understand noctilucent clouds (NLC) and their sensitivity to the variable environment of the polar mesosphere, more needs to be learned about the actual cloud particle population. Optical measurements are today the only means of obtaining information about the size of mesospheric ice particles. In order to efficiently access particle sizes, scattering experiments need to be performed in the Mie scattering regime, thus requiring wavelengths of the order of the particle size. Previous studies of NLC have been performed at wavelengths down to 355 nm from the ground and down to about 200 nm from rockets and satellites. However, from these measurements it is not possible to access the smaller particles in the mesospheric ice population. This current lack of knowledge is a major limitation when studying important questions about the nucleation and growth processes governing NLC and related particle phenomena in the mesosphere. We show that NLC measurements in the extreme ultraviolet, in particular using solar Lyman-α radiation at 121.57 nm, are an efficient way to further promote our understanding of NLC particle size distributions. This applies both to global measurements from satellites and to detailed in situ studies from sounding rockets. Here, we present examples from recent rocket-borne studies that demonstrate how ambiguities in the size retrieval at longer wavelengths can be removed by invoking Lyman-α. We discuss basic requirements and instrument concepts for future rocket-borne NLC missions. In order for Lyman-α radiation to reach NLC altitudes, high solar elevation and, hence, daytime conditions are needed. Considering the effects of Lyman-α on NLC in general, we argue that the traditional focus of rocket-borne NLC missions on twilight conditions has limited our ability to study the full complexity of the summer mesopause environment.

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