scholarly journals Network of Palladium-Based Nanorings Synthesized by Liquid-Phase Reduction Using DMSO-H2O: In Situ Monitoring of Structure Formation and Drying Deformation by ASEM

2020 ◽  
Vol 21 (9) ◽  
pp. 3271 ◽  
Author(s):  
Takuki Komenami ◽  
Akihiro Yoshimura ◽  
Yasunari Matsuno ◽  
Mari Sato ◽  
Chikara Sato
Keyword(s):  
Surface Tension ◽  
Liquid Phase ◽  
Aqueous Solutions ◽  
Critical Point ◽  
Synthesis Method ◽  
Three Dimensional ◽  
In Situ Monitoring ◽  
Critical Point Drying ◽  
Micrometer Size

We developed a liquid-phase synthesis method for Pd-based nanostructure, in which Pd dissolved in dimethyl sulfoxide (DMSO) solutions was precipitated using acid aqueous solution. In the development of the method, in situ monitoring using atmospheric scanning electron microscopy (ASEM) revealed that three-dimensional (3D) Pd-based nanonetworks were deformed to micrometer-size particles possibly by the surface tension of the solutions during the drying process. To avoid surface tension, critical point drying was employed to dry the Pd-based precipitates. By combining ASEM monitoring with critical point drying, the synthesis parameters were optimized, resulting in the formation of lacelike delicate nanonetworks using citric acid aqueous solutions. Precipitation using HCl acid aqueous solutions allowed formation of 500-nm diameter nanorings connected by nanowires. The 3D nanostructure formation was controllable and modifiable into various shapes using different concentrations of the Pd and Cl ions as the parameters.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

3D Simulation of Tunnel Collapse Consolidation and In Situ Monitoring Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 3551-3555
Author(s):  
Zhi Min Chen ◽  
De An Zhao
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
In Situ Monitoring ◽  
3D Simulation ◽  
Actual Situation ◽  
Consolidation Effect ◽  
Tunnel Collapse ◽  
Simulation Results ◽  
Shallow Buried Tunnel

A shallow buried tunnel was collapsed during construction. According to the actual situation of the tunnel, different collapse consolidation schemes were put forward and corresponding three-dimensional finite difference numerical models were established and analyzed using FLAC3D software. Base on the 3D Simulation results, a collapse consolidation scheme was determined and constructed. The in-situ monitoring results of vault subsidence and convergence displacement were consistent approximately with the 3D Simulation results. The in-situ measured results were in line with the specification’s allowance and show that the consolidation effect of reinforced concrete casing arch and ahead grouting method is good. This could be referenced for similar engineering.

scholarly journals Vertical and Horizontal Profiles of Particulate Matter and Black Carbon Near Elevated Highways Based on Unmanned Aerial Vehicle Monitoring

2020 ◽  
Vol 12 (3) ◽  
pp. 1204 ◽  
Author(s):  
Rong Cao ◽  
Bai Li ◽  
Hong-Wei Wang ◽  
Shikang Tao ◽  
Zhong-Ren Peng ◽  
...  
Keyword(s):  
Black Carbon ◽  
Dispersion Model ◽  
Three Dimensional ◽  
Ground Level ◽  
In Situ Monitoring ◽  
Pollution Dispersion ◽  
Vehicle Monitoring ◽  
Aerial Vehicle ◽  
Monitoring Technologies

Highways passing through cities cause additional pollution inside the city. However, most of the current studies are using ground-based monitoring technologies, which make it difficult to capture the dispersion patterns of pollutants near elevated highways or transportation interchanges. The purpose of this study is to discover short-term three-dimensional variations in traffic-related pollutants based on unmanned aerial vehicles. The monitoring locations are at suburban elevated highway and transportation interchanges. The monitoring parameters include the particle number concentration (PN), particle mass concentration (PM), and black carbon (BC). The vertical profiles showed that most air pollutants increased significantly with the height of the elevated highways. Compared with the ground level, PNs increased by 54%–248% and BC increased by 201%. The decline rate of particle concentrations decreased with the increase of height and remained stable after 120 m. Furthermore, the R2 heatmap for regressions between each altitude showed that the linear relationship between 0–120 m was higher than that of other altitudes. In horizontal profiles, PNs spread to 100 m and then began to decline, BC began to decay rapidly after 50 m, but PMs varied less. After crossing another highway, PNs increased by 69–289%, PMs by 7–28%, and BC by 101%. Furthermore, the formation of new particles was observed at both locations as PN3 increased with distance within 100 m from the highway. This paper fills in the void of three-dimensional in situ monitoring near elevated highways, and can help develop and refine a three-dimensional traffic-related air pollution dispersion model and assess the impacts of transportation facilities on the urban environment.

Advances in In Situ SiC Growth Analysis Using Cone Beam Computed Tomography

2019 ◽  
Vol 963 ◽  
pp. 5-9 ◽  
Author(s):  
Michael Salamon ◽  
Matthias Arzig ◽  
Norman Uhlmann ◽  
Peter J. Wellmann
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
In Situ Monitoring ◽  
Material Structure ◽  
Two Dimensional ◽  
Accurate Analysis ◽  
X Ray ◽  
Characteristic Features ◽  
Third Dimension

Computed Tomography is becoming a valuable method for the in-situ monitoring of vapor grown silicon carbide single crystals [1]. Already the two-dimensional X-ray radiography has shown the potential of surveilling the growth process [2] and its characteristic features like the evolution of the facet, the crystal volume or the source material structure from one imaging plane. Even though the demands on imaging capability of the applied X-ray components used for a tomographic analysis are higher than for two-dimensional imaging, the extension of this method to the third dimension is highly beneficial. It allows investigating the full geometry and three-dimensional location of the features and by this provides a more accurate analysis. In this contribution we present the physical characteristics and the latest advances of our technique for the visualization of facets.

scholarly journals Non-Invasive Measurement, Mathematical Simulation and In Situ Detection of Biofilm Evolution in Porous Media: A Review

2021 ◽  
Vol 11 (4) ◽  
pp. 1391
Author(s):  
Yajun Zhang ◽  
Aoshu Xu ◽  
Xin Lv ◽  
Qian Wang ◽  
Caihui Feng ◽  
...  
Keyword(s):  
Porous Media ◽  
Mathematical Simulation ◽  
Pore Space ◽  
Three Dimensional ◽  
Structural Complexity ◽  
In Situ Monitoring ◽  
Spatiotemporal Resolution ◽  
Non Invasive ◽  
Invasive Measurement

The development of biofilms and the related changes in porous media in the subsurface cannot be directly observed and evaluated. The primary reason that the mechanism of biofilm clogging in porous media cannot be clearly demonstrated is due to the opacity and structural complexity of three-dimensional pore space. Interest in exploring methods to overcome this limitation has been increasing. In the first part of this review, we introduce the underlying characteristics of biofilm in porous media. Then, we summarize two approaches, non-invasive measurement methods and mathematical simulation strategies, for studying fluid–biofilm–porous medium interaction with spatiotemporal resolution. We also discuss the advantages and limitations of these approaches. Lastly, we provide a perspective on opportunities for in situ monitoring at the field site.

Critical Point Drying of Freeze-Fractured Tissue For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 452-453 ◽  
Author(s):  
Walter J. Humphreys ◽  
Ben O. Spurlock ◽  
Janet S. Johnson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Tension ◽  
Plastic Deformation ◽  
Critical Point ◽  
Crystal Formation ◽  
Exposed Surface ◽  
Internal Surfaces ◽  
Critical Point Drying ◽  
Scanning Electron

The critical point method eliminates distortion that might have been caused by surface tension during drying of specimens being prepared for scanning electron microscopy. Such preparations can be made rapidly and routinely, and the structural fidelity of surfaces of cells and tissues thus prepared is excellent. But attempts to look inside the tissues or cells with the scanning electron microscope have been less successful. Critical point dried tissue can be broken or cut, and the exposed surface viewed. But plastic deformation of the exposed surface structures caused by the cutting or breaking severely limits the usefulness of this approach. Plastic deformation is minimized when tissue is freeze-fractured to expose internal surfaces, and the water (ice) can be sublimed away from small fragments of tissue without surface tension distortion by freeze-drying the specimen in a vacuum. But freeze damage, resulting mainly from ice crystal formation, is very difficult to avoid.

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