scholarly journals Short Communication: Mechanism and Prevention of Irreversible Trapping of Atmospheric He During Mineral Crushing

2022 ◽  
Author(s):  
Stephen Ellis Cox ◽  
Hayden Bryce Dutcher Miller ◽  
Florian Hofmann ◽  
Kenneth Anthony Farley
Keyword(s):  
Low Temperature ◽  
Vacuum Chamber ◽  
Short Communication ◽  
Noble Gases ◽  
Noble Gas ◽  
Fine Powder ◽  
Analytical Techniques ◽  
Inert Atmosphere ◽  
Laboratory Equipment ◽  
Fine Grained

Abstract. A pervasive challenge in noble gas geochemistry is to ensure that analytical techniques do not modify the composition of the noble gases in the samples. Noble gases are present in the atmosphere and are used in a number of manufacturing procedures and by laboratory equipment. Of particular concern is the introduction of atmospheric or laboratory noble gases to samples during preparation before samples are placed in a vacuum chamber for analysis. Recent work has shown the potential for contamination of crushed samples with air-derived He that is not released by placing the samples under vacuum at low temperature. Using pure He gas as a tracer, we show that the act of crushing samples to a fine powder itself can introduce He contamination, but that this is easily avoided by crushing under liquid or in an inert atmosphere. Because the He is trapped during crushing, the same concern does not extend to samples that are naturally fine-grained when collected. The degree of He contamination even from crushing samples to sizes smaller than typically used for geochronology is insignificant for samples at least 1 Ma and with more than 1 ppm U when the guidelines outlined here are followed.

Application of an image management system in microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1052-1053
Author(s):  
Richard S. Chemock
Keyword(s):  
Data Storage ◽  
Cost Savings ◽  
Image Data ◽  
Analytical Techniques ◽  
Operational Mode ◽  
Fine Grained ◽  
Image Recording ◽  
Primary Output ◽  
Capacity Data ◽  
Image Management System

One of the most common tasks in a typical analysis lab is the recording of images. Many analytical techniques (TEM, SEM, and metallography for example) produce images as their primary output. Until recently, the most common method of recording images was by using film. Current PS/2R systems offer very large capacity data storage devices and high resolution displays, making it practical to work with analytical images on PS/2s, thereby sidestepping the traditional film and darkroom steps. This change in operational mode offers many benefits: cost savings, throughput, archiving and searching capabilities as well as direct incorporation of the image data into reports.The conventional way to record images involves film, either sheet film (with its associated wet chemistry) for TEM or PolaroidR film for SEM and light microscopy. Although film is inconvenient, it does have the highest quality of all available image recording techniques. The fine grained film used for TEM has a resolution that would exceed a 4096x4096x16 bit digital image.

TRI-MARK TM-811N2

Alloy Digest ◽  
1983 ◽  
Vol 32 (4) ◽  
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steels ◽  
Nickel Steel ◽  
Fine Grained ◽  
Subzero Temperatures ◽  
Steel Weld Metal ◽  
Alloy Steels ◽  
Welding Electrode

Abstract TRI-MARK TM-811N2 is a flux-cored welding electrode for all position semiautomatic arc welding. It is designed to weld 2-3% nickel steels for applications requiring good toughness at subzero temperatures; in addition, it is used to weld various other high-strength low-alloy steels and various fine-grained steels with low-temperature toughness. Tri-Mark TM-811N2 is used to deposit typically 2.35% nickel steel weld metal with good low-temperature impact properties. It is used for shipbuilding, oil rigs and similar structures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-389. Producer or source: Tri-Mark Inc..

Investigation of low- and high-resistance Ni–Ge–Au ohmic contacts to n+ GaAs using electron microbeam and surface analytical techniques

1996 ◽  
Vol 11 (5) ◽  
pp. 1244-1254 ◽  
Author(s):  
Nancy E. Lumpkin ◽  
Gregory R. Lumpkin ◽  
K. S. A. Butcher
Keyword(s):  
Electron Microscopy ◽  
Ohmic Contacts ◽  
Analytical Electron Microscopy ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Two Phase ◽  
Low Resistance ◽  
Fine Grained ◽  
Multiphase Microstructure ◽  
Transmission Electron

A process for the formation of low-resistance Ni–Ge–Au ohmic contacts to n+ GaAs has been refined using multivariable screening and response surface experiments. Samples from the refined, low-resistance process (which measure 0.05 ± 0.02 Ω · mm) and the unrefined, higher resistance process (0.17 ± 0.02 Ω · mm) were characterized using analytical electron microscopy (AEM), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and x-ray photoemission spectroscopy (XPS) depth profiling methods. This approach was used to identify microstructural differences and compare them with electrical resistance measurements. Analytical results of the unrefined ohmic process sample reveal a heterogeneous, multiphase microstructure with a rough alloy-GaAs interface. The sample from the refined ohmic process exhibits an alloy which is homogeneous, smooth, and has a fine-grained microstructure with two uniformly distributed phases. XPS analysis for the refined ohmic process sample indicates that the Ge content is relatively depleted in the alloy (relative to the deposited Ge amount) and enriched in the GaAs. This is not evidenced in the unrefined ohmic process sample. Our data lead us to conclude that a smooth, uniform, two-phase microstructure, coupled with a shift in Ge content from the post-alloy metal to the GaAs, is important in forming low-resistance ohmic contacts.

Low-Temperature Fine-Grained Alumina?Aluminum Titanate Composites Produced from a Titania-Coated Alumina Precursor

2007 ◽  
Vol 90 (10) ◽  
pp. 3091-3094 ◽  
Author(s):  
Jayasankar Mani ◽  
Solaiappan Ananthakumar ◽  
Poothayil Mukundan ◽  
Krishna Gopakumar Warrier
Keyword(s):  
Low Temperature ◽  
Aluminum Titanate ◽  
Fine Grained

Humidity effects in Fe16N2 fine powder preparation by low-temperature nitridation

2010 ◽  
Vol 183 (9) ◽  
pp. 2236-2241 ◽  
Author(s):  
Kohetsu Yamanaka ◽  
Yuki Onuma ◽  
Shohei Yamashita ◽  
Yuji Masubuchi ◽  
Takashi Takeda ◽  
...  
Keyword(s):  
Low Temperature ◽  
Fine Powder ◽  
Powder Preparation ◽  
Humidity Effects

Development of Low-Temperature Sintering Cu Nanoparticles

2013 ◽  
Vol 1513 ◽  
Author(s):  
Toshitaka Ishizaki ◽  
Ryota Watanabe ◽  
Kunio Akedo ◽  
Toshikazu Satoh
Keyword(s):  
Electron Microscopy ◽  
Fatty Acids ◽  
Low Temperature ◽  
Decanoic Acid ◽  
Inert Atmosphere ◽  
Processing Temperature ◽  
Low Temperature Sintering ◽  
Cu Nanoparticles ◽  
Transmission Electron ◽  
Oleyl Amine

ABSTRACTCu nanoparticles capped with fatty acids and amines were developed as low-temperature sintering materials. The fatty acids and amines used were decanoic acid + decyl amine (C10) and oleic acid + oleyl amine (C18), respectively. The synthesized Cu nanoparticles were analyzed using X-ray diffraction, transmission electron microscopy, and thermogravimetric and differential thermal analysis. Because both of the capping layers could be decomposed at temperatures lower than 300°C even under an inert atmosphere, bonding and sintering experiments could be carried out in the absence of oxygen to prevent the oxidation of the Cu nanoparticles. The sintered structures were observed using scanning electron microscopy. The shear strengths of Cu plates bonded using the C18 Cu nanoparticles were larger than those of plates bonded using the C10 Cu nanoparticles. At 300°C, the strength was higher than 30 MPa, and of the same order as ordinary high-temperature solders, even though the processing temperature was low. The resistivity of a film sintered using the C18 Cu nanoparticles was 12 μΩcm at 300°C, which was lower than the values reported in previous studies.

Liquid noble gases for dark matter searches: An updated survey

2015 ◽  
Vol 30 (26) ◽  
pp. 1530053 ◽  
Author(s):  
R. Bernabei ◽  
P. Belli ◽  
A. Incicchitti ◽  
F. Cappella ◽  
R. Cerulli
Keyword(s):  
Dark Matter ◽  
Noble Gases ◽  
Noble Gas ◽  
Low Energy ◽  
Gas Detectors ◽  
Double Phase ◽  
Methodological Comparison ◽  
Direct Dark Matter ◽  
Energy Physics

An updated technical and methodological comparison of liquid noble gas experiments is presented with particular attention to the low energy physics application of double-phase noble gas detectors in direct Dark Matter investigations.

High Velocity Pulsed Plasma Thermal Spray

2000 ◽  
Author(s):  
F.D. Witherspoon ◽  
D.W. Massey ◽  
R.W. Kincaid ◽  
G.C. Whichard ◽  
T.A. Mozhi
Keyword(s):  
Thermal Spray ◽  
High Velocity ◽  
Vacuum Chamber ◽  
Thermal Environment ◽  
Diagnostic System ◽  
Inert Atmosphere ◽  
Pulsed Plasma ◽  
Combustible Gases ◽  
Accelerated Particles

Abstract The quality and durability of coatings produced by virtually all thermal spray techniques could be improved by increasing the velocity with which coating particles impact the substrate. Additionally, better control of the chemical and thermal environment seen by the particles during flight is crucial to the quality of the coating. A high velocity thermal spray device is under development through a BMDO SBIR project which provides significantly higher impact velocity for accelerated particles than is currently available with existing thermal spray devices. This device utilizes a pulsed plasma as the accelerative medium for powders introduced into the barrel. Recent experiments using a Control-Vision diagnostic system showed that the device can accelerate stainless steel and WC-Co powders to velocities ranging from 1500 to 2200 m/s. These high velocities are accomplished without the use of combustible gases, and without the need of a vacuum chamber, while maintaining an inert atmosphere for the particles during acceleration. The high velocities corresponded well to modeling predictions, and these same models suggest that velocities as high as 3000 m/s or higher are possible.

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