Formation of brown carbon on Fe-bearing clay from volatile phenol under simulated atmospheric conditions

2020 ◽  
Vol 228 ◽  
pp. 117427
Author(s):  
Jingyi Ling ◽  
Feng Sheng ◽  
Yi Wang ◽  
Anping Peng ◽  
Xin Jin ◽  
...  
Keyword(s):  
Atmospheric Conditions ◽  
Brown Carbon ◽  
Volatile Phenol

scholarly journals Photophoretic spectroscopy in atmospheric chemistry – high-sensitivity measurements of light absorption by a single particle

2020 ◽  
Vol 13 (6) ◽  
pp. 3191-3203
Author(s):  
Nir Bluvshtein ◽  
Ulrich K. Krieger ◽  
Thomas Peter
Keyword(s):  
Atmospheric Chemistry ◽  
Single Particle ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Experimental System ◽  
High Sensitivity ◽  
Atmospheric Conditions ◽  
Brown Carbon ◽  
Radiative Balance ◽  
Low Sensitivity

Abstract. Light-absorbing organic atmospheric particles, termed brown carbon, undergo chemical and photochemical aging processes during their lifetime in the atmosphere. The role these particles play in the global radiative balance and in the climate system is still uncertain. To better quantify their radiative forcing due to aerosol–radiation interactions, we need to improve process-level understanding of aging processes, which lead to either “browning” or “bleaching” of organic aerosols. Currently available laboratory techniques aim to simulate atmospheric aerosol aging and measure the evolving light absorption, but they suffer from low sensitivity and precision. This study describes the use of electrodynamic balance photophoretic spectroscopy (EDB-PPS) for high-sensitivity and high-precision measurements of light absorption by a single particle. We demonstrate the retrieval of the time-evolving imaginary part of the refractive index for a single levitated particle in the range of 10−4 to 10−5 with uncertainties of less than 25 % and 60 %, respectively. The experimental system is housed within an environmental chamber, in which aging processes can be simulated in realistic atmospheric conditions and lifetimes of days to weeks. This high level of sensitivity enables future studies to explore the major processes responsible for formation and degradation of brown carbon aerosols.

scholarly journals Photophoretic spectroscopy in atmospheric chemistry – high sensitivity measurements of light absorption by a single particle

2020 ◽  
Author(s):  
Nir Bluvshtein ◽  
Ulrich K. Krieger ◽  
Thomas Peter
Keyword(s):  
Atmospheric Chemistry ◽  
Single Particle ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Experimental System ◽  
High Sensitivity ◽  
Atmospheric Conditions ◽  
Brown Carbon ◽  
Radiative Balance ◽  
Low Sensitivity

Abstract. Light absorbing organic atmospheric particles, termed brown carbon, undergo chemical and photochemical aging processes during their lifetime in the atmosphere. The role these particles play in the global radiative balance and in the climate system is still uncertain. To better quantify their radiative forcing due to aerosol-radiation interactions, we need to improve process level understanding of aging processes, which lead to either "browning" or "bleaching" of organic aerosols. Currently available laboratory techniques aim to simulate atmospheric aerosol aging and measure the evolving light absorption, but suffer from low sensitivity and precision. This study describes the use of electrodynamic balance photophoretic spectroscopy (EDB-PPS) for high sensitivity and high precision measurements of light absorption by a single particle. We demonstrate the retrieval of time-evolving imaginary part of the refractive index for a single levitated particle in the range of 10−4 to 10−5 with uncertainties of less than 25 % and 60 %, respectively. The experimental system is housed within an environmental chamber, in which aging processes can be simulated in realistic atmospheric conditions and lifetime of days to weeks. This high level of sensitivity enables future studies to explore the major processes responsible for formation and degradation of brown carbon aerosols.

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

1996 ◽  
Vol 54 ◽  
pp. 218-219
Author(s):  
H. S. Kim ◽  
R. U. Lee
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Surface Preparation ◽  
Optical Microscope ◽  
Heating Element ◽  
Incomplete Fusion ◽  
Atmospheric Conditions ◽  
Leak Test ◽  
High Temperature Side ◽  
Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 510-511 ◽  
Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann
Keyword(s):  
Heavy Metal ◽  
High Resolution ◽  
Freeze Drying ◽  
Atmospheric Conditions ◽  
Vacuum Equipment ◽  
Transmission Electron ◽  
Gas Atmosphere ◽  
Gas Molecules ◽  
Residual Gas ◽  
Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

Contribution of brown carbon and lensing to the direct radiative effect of carbonaceous aerosols from biomass and biofuel burning emissions

2015 ◽  
pp. n/a-n/a ◽  
Author(s):  
Rawad Saleh ◽  
Marguerite Marks ◽  
Jinhyok Heo ◽  
Peter J. Adams ◽  
Neil M. Donahue ◽  
...  
Keyword(s):  
Carbonaceous Aerosols ◽  
Radiative Effect ◽  
Brown Carbon

MUELLER ALLOY 3140

Alloy Digest ◽  
1983 ◽  
Vol 32 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
Heat Treating ◽  
Lead Content ◽  
Atmospheric Conditions ◽  
Excellent Corrosion Resistance ◽  
High Copper ◽  
Screw Machine

Abstract MUELLER Alloy 3140 is a high-copper alloy with moderate strength, a rich bronze color and excellent corrosion resistance. Its lead content gives it excellent machinability which makes it suitable for screw-machine applications. Its uses include many screw-machine products, decorative hardware, pickling crates and parts to resist severe atmospheric conditions. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-451. Producer or source: Mueller Brass Company.

Choose you own scientific experiment: Triggering debris flows and flash floods

2016 ◽  
Author(s):  
Thea Turkington
Keyword(s):  
Debris Flows ◽  
Flash Floods ◽  
The Other ◽  
Background Information ◽  
Atmospheric Conditions ◽  
Scientific Experiment

Landslides and flash floods result in many fatalities around the globe. Understanding what triggers these events is therefore vital, although how to approach this problem is not straight forward. After background information for the experiment and some guidelines, two options are presented to learn more about the triggers of debris flows: (A) using rainfall or (B) the atmospheric conditions. You can then choose the option that appears more useful and interesting to you (you can always go back and read the other experiment afterwards). The article then ends with a reflection on the results.

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