scholarly journals Effects of water, ammonia and formic acid on HO2 + Cl reactions under atmospheric conditions: competition between a stepwise route and one elementary step

RSC Advances ◽  
2019 ◽  
Vol 9 (37) ◽  
pp. 21544-21556 ◽  
Author(s):  
Tianlei Zhang ◽  
Yongqi Zhang ◽  
Mingjie Wen ◽  
Zhuo Tang ◽  
Bo Long ◽  
...  

The effects of acidic (FA), neutral (WM) and basic (AM) catalysts on the energetic and kinetic aspects of the HO2 + Cl reaction have been studied. At 298 K, the catalytic order of FA, WM and AM is WM > FA > AM.

RSC Advances ◽  
2019 ◽  
Vol 9 (40) ◽  
pp. 22987-22987
Author(s):  
Tianlei Zhang ◽  
Yongqi Zhang ◽  
Mingjie Wen ◽  
Zhuo Tang ◽  
Bo Long ◽  
...  

Correction for ‘Effects of water, ammonia and formic acid on HO2 + Cl reactions under atmospheric conditions: competition between a stepwise route and one elementary step’ by Tianlei Zhang et al., RSC Adv., 2019, 9, 21544–21556.


Author(s):  
H. S. Kim ◽  
R. U. Lee

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.


Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann

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.


2019 ◽  
Vol 6 (3) ◽  
pp. 104-107
Author(s):  
Marina Vladimirovna Lebedeva ◽  
Alexey Petrovich Antropov ◽  
Alexander Victorovich Ragutkin ◽  
Nicolay Andreevich Yashtulov

In paper electrode materials with palladium nanoparticles on polymer matrix substrates for energy sources have been formed. Nanocomposites were investigated by atomic force and scanning electron microscopy. The catalytic activity of formed electrodes in the formic acid oxidation reaction was evaluated by voltammetry method.


Author(s):  
Manuel Goubet ◽  
Robert Georges ◽  
P. Roy ◽  
Atef Jabri ◽  
Pascale Soulard ◽  
...  

Author(s):  
Weixing Li ◽  
Walther Caminati ◽  
Rolf Meyer ◽  
Qian Gou ◽  
Luca Evangelisti

1963 ◽  
Vol 43 (3) ◽  
pp. 345-360 ◽  
Author(s):  
Stanley Kushinsky ◽  
Jane (Wu) Tang

ABSTRACT A convenient and mild procedure is described in this paper whereby free and conjugated oestrogens may be extracted from urine. The extracts containing approximately 90 per cent of the oestrogens are devoid of most of the extraneous material and may be reduced in volume to less than 1/15 of that of the urine. The procedure consists of the following steps: (1) a 10 per cent (v/v) solution of a high molecular weight secondary amine (Amberlite LA-2, Rohm and Haas) in ethyl acetate is washed with formic acid and water, (2) the oestrogens in urine (acidified to pH 2 or 3 with H2SO4) are extracted with the LA-2 solution, (3) the oestrogen fraction is back-extracted from the organic solution with dilute aqueous ammonia.


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