Gas flow modeling for focused ion beam (FIB) repair processes

2004 ◽  
Author(s):  
Mohamed S. El-Morsi ◽  
Alexander C. Wei ◽  
Gregory F. Nellis ◽  
Roxann L. Engelstad ◽  
Sybren Sijbrandij ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Flow Modeling ◽  
Repair Processes

High-Precision Gas Sensor Based on Photonic Bandgap Fiber Cell

2009 ◽  
Vol 147-149 ◽  
pp. 131-136 ◽  
Author(s):  
Joanna Pawłat ◽  
Xue Feng Li ◽  
Tadashi Sugiyama ◽  
Takahiro Matsuo ◽  
Yurij Zimin ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Photonic Bandgap ◽  
Ion Beam ◽  
Sample Volume ◽  
Gas Cell ◽  
Gas Concentration ◽  
Photonic Bandgap Fiber ◽  
New Device ◽  
Microstructured Optical Fiber

As one of applications for Microstructured Optical Fiber, a new device for measurement of low gas concentration was designed. In the developed system the Photonic Bandgap Fiber (PBGF) was used as a gas cell. Proposed technique allowed reducing gas sample volume to 0.01 cc. The gas flow inside core of fiber was simulated and result was confirmed experimentally. During the experimental work several types of fibers of various parameters were specially designed, produced and used. Core diameters ranged from 10.9 μm to 700 μm. Various cutting techniques for fibers such as using the fiber cleaver, Focused Ion Beam and Cross Section Polisher were investigated.

scholarly journals Characterization of a Si-SiO2 Mixture Generated from SiO(g) and CO(g)

2019 ◽  
Vol 50 (6) ◽  
pp. 2667-2680 ◽  
Author(s):  
Andrea Broggi ◽  
Merete Tangstad ◽  
Eli Ringdalen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Liquid Silicon ◽  
Inert Gas ◽  
Dissolved Carbon ◽  
Sic Particles ◽  
Transmission Electron ◽  
A Minor

Abstract The reaction between SiO(g) and CO(g) is a relevant intermediate reaction in the silicon production process. One of the products generated from this gas mixture is called by its color, brown condensate. In this paper, SiO(g) and CO(g) are produced from SiO2-SiC pellets. The reaction between the two gases occurred on SiC particles. Inert gas was injected at different flows. The SiC particles were collected, and the brown condensate deposited on them was characterized by electron probe microanalysis, X-ray photoelectron spectroscopy, and focused ion beam preparation samples for transmission electron microscope analysis. The brown condensate consists of a mixture of Si spheres embedded in a SiO2 matrix. The compound generates in the temperature range from 1400 °C to 1780 °C (1673 K to 2053 K), and in the SiO(g) partial pressure range between 0.534 and 0.742, depending on the inert gas flow. SiC crystallites are located at the Si-SiO2 interface. Carbides are believed to generate from the reaction between liquid silicon and CO(g). Carbides may also precipitate from reaction between dissolved carbon and liquid silicon, but to a minor extent. Both mechanisms are believed to happen above the melting point of silicon and in the softening range of silica.

scholarly journals Gas flow through atomic-scale apertures

2020 ◽  
Vol 6 (51) ◽  
pp. eabc7927
Author(s):  
Jothi Priyanka Thiruraman ◽  
Sidra Abbas Dar ◽  
Paul Masih Das ◽  
Nasim Hassani ◽  
Mehdi Neek-Amal ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atomic Scale ◽  
Gas Flows ◽  
Narrow Channels ◽  
Molecular Separation ◽  
Transmission Electron ◽  
Ultralow Concentrations ◽  
Atomic Limit

Gas flows are often analyzed with the theoretical descriptions formulated over a century ago and constantly challenged by the emerging architectures of narrow channels, slits, and apertures. Here, we report atomic-scale defects in two-dimensional (2D) materials as apertures for gas flows at the ultimate quasi-0D atomic limit. We establish that pristine monolayer tungsten disulfide (WS2) membranes act as atomically thin barriers to gas transport. Atomic vacancies from missing tungsten (W) sites are made in freestanding (WS2) monolayers by focused ion beam irradiation and characterized using aberration-corrected transmission electron microscopy. WS2 monolayers with atomic apertures are mechanically sturdy and showed fast helium flow. We propose a simple yet robust method for confirming the formation of atomic apertures over large areas using gas flows, an essential step for pursuing their prospective applications in various domains including molecular separation, single quantum emitters, sensing and monitoring of gases at ultralow concentrations.

scholarly journals Porosity and permeability determinations of organic rich Posidonia shales based on 3D analyses by FIB-SEM microscopy

2016 ◽  
Author(s):  
Georg H. Grathoff ◽  
Markus Peltz ◽  
Frieder Enzmann ◽  
Stephan Kaufhold
Keyword(s):  
Organic Matter ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Navier Stokes ◽  
Pore Size Distributions ◽  
Two Samples ◽  
Segmented Images ◽  
Porosity And Permeability ◽  
Organic Particles

Abstract. The goal of this study is to better understand the porosity and permeability in shales to improve modelling fluid and gas flow related to shale diagenesis. Two samples (WIC and HAD) were investigated, both Mid Jurassic Posidonia organic rich shales from central Germany of different maturity (WIC R0 0.53 % and HAD R0 1.45 %). The method for image collection was Focused Ion Beam (FIB) microscopy coupled with Scanning Electron Microscopy (SEM). For image and data analysis Avizo and GeoDict was used. Porosity was calculated from segmented 3D FIB based images and permeability was simulated by a Navier Stokes-Brinkman solver in the segmented images. Results show that the quantity and distribution of pore clusters and pores (> 40 nm) are similar. The largest pores are located within carbonates and clay minerals, whereas the smallest pores are within the matured organic matter. Orientation of the pores calculated as pore paths showed minor directional differences between the samples, possibly due to maturation. Both samples have no axis connectivity of pore clusters in the x, y, and z direction on the scale of 10 to 20 of micrometer, but do show connectivity on the micrometer scale. The volume of organic matter in the studied volume is representative of the TOC in the samples. Organic matter does show axis connectivity in the x, y, and z direction. With increasing maturity the porosity in organic matter increases from close to 0 to more than 5 %. These pores are small and in the large organic particles have little connection to the mineral matrix. Continuous pore size distributions are compared with Mercury Intrusion Porosimetry (MIP) data. Minor differences are caused by resolution limits of the FIB-SEM and by the development of small pores during the maturation of the organic matter. Calculations show no permeability when only considering visible pores due to the lack of axis connectivity. Adding the organics with a background permeability of 1e-22 m2 to the calculations, the total permeability increased by one to two orders of magnitude depending on the direction of flow boundary conditions. Our results compare well with experimental data from the literature suggesting that upscaling may be possible in the future.

scholarly journals Porosity and permeability determination of organic-rich Posidonia shales based on 3-D analyses by FIB-SEM microscopy

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1145-1156 ◽  
Author(s):  
Georg H. Grathoff ◽  
Markus Peltz ◽  
Frieder Enzmann ◽  
Stephan Kaufhold
Keyword(s):  
Organic Matter ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Navier Stokes ◽  
Permeability Coefficients ◽  
Pore Size Distributions ◽  
Two Samples ◽  
Order Of Magnitude ◽  
Porosity And Permeability

Abstract. The goal of this study is to better understand the porosity and permeability in shales to improve modelling fluid and gas flow related to shale diagenesis. Two samples (WIC and HAD) were investigated, both mid-Jurassic organic-rich Posidonia shales from Hils area, central Germany of different maturity (WIC R0 0.53 % and HAD R0 1.45 %). The method for image collection was focused ion beam (FIB) microscopy coupled with scanning electron microscopy (SEM). For image and data analysis Avizo and GeoDict was used. Porosity was calculated from segmented 3-D FIB based images and permeability was simulated by a Navier Stokes–Brinkman solver in the segmented images. Results show that the quantity and distribution of pore clusters and pores (≥  40 nm) are similar. The largest pores are located within carbonates and clay minerals, whereas the smallest pores are within the matured organic matter. Orientation of the pores calculated as pore paths showed minor directional differences between the samples. Both samples have no continuous connectivity of pore clusters along the axes in the x, y, and z direction on the scale of 10 to 20 of micrometer, but do show connectivity on the micrometer scale. The volume of organic matter in the studied volume is representative of the total organic carbon (TOC) in the samples. Organic matter does show axis connectivity in the x, y, and z directions. With increasing maturity the porosity in organic matter increases from close to 0 to more than 5 %. These pores are small and in the large organic particles have little connection to the mineral matrix. Continuous pore size distributions are compared with mercury intrusion porosimetry (MIP) data. Differences between both methods are caused by resolution limits of the FIB-SEM and by the development of small pores during the maturation of the organic matter. Calculations show no permeability when only considering visible pores due to the lack of axis connectivity. Adding the organic matter with a background permeability of 1 × 10−21 m2 to the calculations, the total permeability increased by up to 1 order of magnitude for the low mature and decreases slightly for the overmature sample from the gas window. Anisotropy of permeability was observed. Permeability coefficients increase by 1 order of magnitude if simulations are performed parallel to the bedding. Our results compare well with experimental data from the literature suggesting that upscaling may be possible in the future as soon as maturity dependent organic matter permeability coefficients can be determined.

Nanocomposite Polyurethane Foams Via POSS Blends

2002 ◽  
Vol 733 ◽  
Author(s):  
Brock McCabe ◽  
Steven Nutt ◽  
Brent Viers ◽  
Tim Haddad
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polyurethane Foams ◽  
Development Projects ◽  
Polymer Systems ◽  
Polyurethane Resin ◽  
Military Development

AbstractPolyhedral Oligomeric Silsequioxane molecules have been incorporated into a commercial polyurethane formulation to produce nanocomposite polyurethane foam. This tiny POSS silica molecule has been used successfully to enhance the performance of polymer systems using co-polymerization and blend strategies. In our investigation, we chose a high-temperature MDI Polyurethane resin foam currently used in military development projects. For the nanofiller, or “blend”, Cp7T7(OH)3 POSS was chosen. Structural characterization was accomplished by TEM and SEM to determine POSS dispersion and cell morphology, respectively. Thermal behavior was investigated by TGA. Two methods of TEM sample preparation were employed, Focused Ion Beam and Ultramicrotomy (room temperature).

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