Reaction of active nitrogen with perfluorinated olefins

1968 ◽  
Vol 46 (22) ◽  
pp. 3483-3489 ◽  
Author(s):  
N. Madhavan ◽  
W. E. Jones
Keyword(s):  
Microwave Discharge ◽  
Flow System ◽  
Active Nitrogen ◽  
Flow Rates ◽  
Gaseous Products ◽  
Nitrogen Containing Compounds ◽  
Reactant Flow

The reactions of the fluorocarbon olefins, C2F4, C3F6, and C4F8-2, with active nitrogen were studied in a flow system. The active nitrogen was produced by a microwave discharge at a concentration of 2.1 × 10−6 mole/s. The major gaseous products of the reactions are fluorocarbons and their production was studied quantitatively at the temperatures 25, 250, and 400 °C and at a large number of reactant flow rates to a maximum of approximately 3 × 10−6 mole/s.Three nitrogen-containing compounds, FCN, N2O, and a polymer of composition (C3F5N)n were detected as products in all three reactions; FCN and N2O are found only in very small amounts.Mechanisms for each of the reactions are discussed.

scholarly journals THE REACTIONS OF ACTIVE NITROGEN WITH CHLOROMETHANES

1958 ◽  
Vol 36 (9) ◽  
pp. 1223-1226 ◽  
Author(s):  
S. E. Sobering ◽  
C. A. Winkler
Keyword(s):  
Carbon Tetrachloride ◽  
Hydrogen Chloride ◽  
Hydrogen Cyanide ◽  
Active Nitrogen ◽  
Flow Rates ◽  
Product Yields ◽  
Gaseous Products ◽  
Cyanogen Chloride ◽  
Limiting Values ◽  
Reactant Flow

Cyanogen chloride and chlorine were the only gaseous products observed in the reaction of active nitrogen with carbon tetrachloride at 110° and 420 °C. The product yields tended towards limiting values at higher reactant flow rates, and increased with increase of temperature at all flow rates. The reactions of active nitrogen with chloroform and dichloromethane at 260° and 420 °C yielded hydrogen chloride, hydrogen cyanide, and cyanogen, in addition to cyanogen chloride and chlorine. The behavior of the product yields with reactant flow rates and temperature was similar to that of the products from carbon tetrachloride.

THE REACTIONS OF ACTIVE NITROGEN WITH ALKYL CHLORIDES

1956 ◽  
Vol 34 (8) ◽  
pp. 1074-1082 ◽  
Author(s):  
B. Dunford ◽  
H. G. V. Evans ◽  
C. A. Winkler
Keyword(s):  
Hydrogen Cyanide ◽  
Methyl Chloride ◽  
The Other ◽  
Alkyl Chloride ◽  
Initial Attack ◽  
Fast Reaction ◽  
Ethyl Vinyl ◽  
Active Nitrogen ◽  
Flow Rates ◽  
Reactant Flow

The reactions of active nitrogen with methyl, ethyl, vinyl, propyl, and isopropyl chlorides yielded hydrogen cyanide and hydrogen chloride as the main products. Small amounts of cyanogen and a polymer were formed from all the halides, and all except methyl chloride also yielded small amounts of C2 and C3 hydrocarbons. The observed changes in amounts of products recovered with different reactant flow rates were characteristic of a fast reaction in which complete consumption of either reactant occurs when the other is present in excess. Mechanisms for the reactions are suggested on the basis that relatively long-lived complexes are formed in the initial attack of a nitrogen atom on the alkyl chloride.

The reaction of active nitrogen with fluoroethylenes

1982 ◽  
Vol 60 (20) ◽  
pp. 2629-2633 ◽  
Author(s):  
William E. Jones ◽  
Mahmooda G. Ahmed
Keyword(s):  
Mass Spectrometer ◽  
Reaction Mechanisms ◽  
Flow System ◽  
Intermediate Species ◽  
Active Nitrogen ◽  
Reacting Mixtures

The reactions of active nitrogen with the fluoroethylenes C2H3F, 1,1-C2H2F2, C2HF3, and C2F4 have been investigated in a conventional flow system using a mass spectrometer to detect products and intermediate species. Addition of various gases (H, H2, NH3, CH4, N2O, [Formula: see text], and F) to the reacting mixtures provides evidence that both Hand F atoms play significant roles in the reaction mechanisms, while [Formula: see text] does not. A brief discussion of possible mechanisms is presented.

Investigation of Thin Film Growth of B12As2 by Chemical Vapor Deposition

2003 ◽  
Vol 764 ◽  
Author(s):  
R. Nagarajan ◽  
J.H. Edgar ◽  
J. Pomeroy ◽  
M. Kuball ◽  
T. Aselage
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Thin Film Growth ◽  
X Ray Diffraction ◽  
Flow Rates ◽  
X Ray ◽  
Effects Of Temperature ◽  
Reactant Flow

AbstractThe chemical vapor deposition of icosahedral boron arsenide, B12As2, on 6H-SiC (0001) (on and off-axis) substrates was studied using hydrides as the reactants. The effects of temperature and reactant flow rates on the phases deposited and the crystal quality were determined. The growth rate increased with temperature from 1.5μm/h at 1100°C to 5 μm/h at 1400°C and decreased thereafter. X-ray diffraction revealed that the deposits were amorphous when the deposition temperature is below 1150° C. Above 1150°C, smooth B12As2 films were formed on 6H-SiC substrates with an orientation of (0001) B12As2 parallel to 6H-SiC (0001). Raman spectroscopy confirmed the strongly c-axis oriented nature of B12As2 film on 6H-SiC.

Perfusion rates and the transfer of water across isolated guinea pig placenta

1977 ◽  
Vol 232 (6) ◽  
pp. H666-H670
Author(s):  
H. Schroder ◽  
H. P. Leichtweiss
Keyword(s):  
Guinea Pig ◽  
Flow System ◽  
Tritiated Water ◽  
Countercurrent Flow ◽  
Concurrent System ◽  
Flow Rates ◽  
Guinea Pig Placenta ◽  
The Subject ◽  
Pig Placenta ◽  
Relative Transfer

The transfer of tritiated water across the isolated, artificially perfused guinea pig placenta was the subject of 21 experiments. The observed relationship between the flow rates and the relative transfer of water cannot be explained by a concurrent or pool-flow system. If the direction of the fetal flow is reversed, the rate of transfer is lowered. It may be concluded, that the decrease is a result of a change from a nonideal countercurrent flow system to a nonideal concurrent system. This conclusion, however, holds only if all other parameters that determine the exchange as well remain unaffected. In the range of flows investigated, the transfer of water is flow limited.

scholarly journals Experimental Studies of Effect of Land Width in PEM Fuel Cells with Serpentine Flow Field and Carbon Cloth

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 471 ◽  
Author(s):  
Xuyang Zhang ◽  
Andrew Higier ◽  
Xu Zhang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Carbon Cloth ◽  
Pumping Power ◽  
Inlet Flow ◽  
Flow Rates ◽  
Reactant Flow ◽  
Land Width

Flow field plays an important role in the performance of proton exchange membrane (PEM) fuel cells, such as transporting reactants and removing water products. Therefore, the performance of a PEM fuel cell can be improved by optimizing the flow field dimensions and designs. In this work, single serpentine flow fields with four different land widths are used in PEM fuel cells to study the effects of the land width. The gas diffusion layers are made of carbon cloth. Since different land widths may be most suitable for different reactant flow rates, three different inlet flow rates are studied for all the flow fields with four different land widths. The effects of land width and inlet flow rate on fuel cell performance are studied based on the polarization curves and power densities. Without considering the pumping power, the cell performance always increases with the decrease in the land width and the increase in the inlet flow rates. However, when taking into consideration the pumping power, the net power density reaches the maximum at different combinations of land widths and reactant flow rates at different cell potentials.

THE REACTION OF ACTIVE NITROGEN WITH ETHANOL

1965 ◽  
Vol 43 (4) ◽  
pp. 935-939 ◽  
Author(s):  
P. A. Gartaganis
Keyword(s):  
Flow System ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Condensed Discharge ◽  
Preliminary Study ◽  
Fast Flow ◽  
Ethyl Radicals ◽  
Water Hydrogen

The reaction of active nitrogen with ethanol has been investigated in the range 300 to 593 °K using a modified condensed-discharge Wood–Bonhoeffer fast-flow system. The only condensable products found in appreciable amounts were hydrogen cyanide and water. Hydrogen was the main noncondensable product. A very small amount of acetaldehyde was also formed along with traces of ethane, ethylene, methane, acetonitrile, cyanogen, and probably carbon monoxide. The overall activation energy is 3.4 kcal/mole. It is postulated that the mechanism consists of the formation of two fragments NC2H5 and OH, from which the condensable products result as follows:[Formula: see text]A number of products found in trace quantities are produced by concomitant reactions of the hydrogen atoms with methyl radicals, and with ethanol as well as by disproportionation of ethyl radicals to produce ethane and ethylene. A preliminary study of the reaction of active nitrogen with isopropanol indicated that the energy of activation is in line with the energies of activation of methanol and ethanol.

Groundwater age gradient to infer flow rates, hydraulic parameters, aquifer abstraction limits, and storage in the Wairau Plain, New Zealand

2020 ◽  
Author(s):  
Uwe Morgenstern ◽  
Mike Stewart
Keyword(s):  
Hydraulic Conductivity ◽  
Time Series Data ◽  
Flow System ◽  
Groundwater Age ◽  
Mean Transit Time ◽  
Water Levels ◽  
Estuarine Sediments ◽  
Series Data ◽  
Flow Rates ◽  
River Temperature

<p>Groundwater is an important source of water for the Wairau Plain, and there is concern about its sustainable yield because of declining water levels and spring flows in the Wairau Fan. The Wairau Fan is comprised of highly permeable fluvial gravels. The main source of groundwater is loss from the Wairau River channel. The underlying Pleistocene gravels form a significantly less permeable aquifer. Near the coast, estuarine sediments form an aquiclude over the Pleistocene gravels. The main groundwater flow from the gravel fan is forced back to the surface near the confinement boundary feeding highly valued streams with crystal-clear water but declining flow.</p><p>To understand the flow dynamics of the groundwater, we utilised tritium, SF6, and 14C. For the extremely young groundwaters in the unconfined Wairau Fan, <1 year, we developed a dating method that traces the seasonal river temperature variability through the aquifer. The lags of the temperature synodal signal were calibrated to true age via the <sup>18</sup>O synodal signal.</p><p>All groundwaters within the Pleistocene gravels are very old, >100 years, and up to 39,000 years in the Deep Wairau Aquifer. In contrast, throughout the unconfined Wairau Fan we observed only very young groundwater, with mean residence time of 0–1 years, even in the deeper wells of >20 m.</p><p>Flow rates estimated from groundwater age gradients show that in its upper part the unconfined Wairau Fan is well connected to the Wairau River. Extremely high flow rates of up to > 30 km/y in this area indicate extremely high hydraulic conductivity in these Holocene deposits near the river. Towards the coast, the flow rates reduce considerably, to 13 km/y at around the boundary of the confinement, thereafter slowing further to 0.7 km/y near the coast. The reduction in flow rate near the coast, by a factor >20, is related to the flow loss from the aquifer, mainly to the spring belt and through abstraction.</p><p>Hydraulic conductivities, derived from the flow rates, are c. 12,000 m/day in the unconfined Wairau Fan near the river and in the central part of the unconfined Wairau Fan. Near the coast the estimated hydraulic conductivity is 800 m/day. Despite relatively uniform hydraulic conductivities, the Wairau Fan becomes less transmissive downstream due to decreasing piezometric gradients. This is likely to cause the restriction in the flow system. The ‘choking point’ in the flow system of the unconfined Wairau Fan appears to be not the recharge zone near the river but the lower Wairau Fan due to its lower transmissivity by a factor of two.</p><p>To understand the buffer of the entire system against prolonged drought, the mean transit time of the water through the Wairau River catchment was estimated from tritium time-series data to four years, and the active groundwater storage to approximately 6,200M m<sup>3</sup>. The Wairau catchment would be able to maintain baseflow in the river and the aquifer for several years.</p>

Influence of Bubble Sizes on Ozone Solubility Utilization and Disinfection

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1081-1090 ◽  
Author(s):  
Mansoor Ahmad ◽  
Shaukat Farooq
Keyword(s):  
Gas Flow ◽  
Bacterial Population ◽  
Flow System ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Before And After ◽  
Standard Plate ◽  
Plate Counts ◽  
Bubble Sizes ◽  
Ozone Contactor

A disinfection study was carried out in a continuous flow system employing different sizes of ozone bubbles to determine their effects on solubility of ozone, its utilization and inactivation of microorganisms. The bubble sizes were varied by changing the porosity of the diffusers and ozone flow rates through the ozone contactor. Natural bacterial population (standard plate counts) present in the secondary wastewater effluent, was enumerated before and after ozonation. It was found that for a given concentration of ozone at a constant gas flow rate, decrease in bubble sizes resulted in an increase in ozone residual and degree of inactivation of organisms inspite of a decrease in ozone utilization by the wastewater.

The air afterglow and its use in the study of some reactions of atomic oxygen

1958 ◽  
Vol 247 (1248) ◽  
pp. 123-139 ◽  
Keyword(s):  
Nitric Oxide ◽  
Steady State ◽  
Atomic Oxygen ◽  
Microwave Discharge ◽  
Flow System ◽  
Glass Tube ◽  
Inert Gases ◽  
Spatial Decay ◽  
Greenish Yellow ◽  
Catalytic Recombination

The air afterglow has been studied in a flow system by mixing the products of a microwave discharge in oxygen with NO or mixtures of gases and by measuring the intensity of the glow immediately past the point of mixing and farther downstream in a long glass tube at known pressure, composition, and linear velocity of flow. The intensity of the greenish yellow chemiluminescence is shown to be proportional to the concentrations of atomic oxygen and nitric oxide, and independent of the nature or amount of added inert gases. An average quantum (5500 Å) is emitted for every 10 7 collisions of O with NO. The concentration of atomic oxygen is determined by a 'titration with NO 2 in which the end-point is indicated by complete extinction of the glow all along the tube, and which is made possible by the great speed of the reaction O + NO 2 → O 2 + NO. Observation of the spatial decay of the glow under steady-state conditions is well suited to the study of reactions of atomic oxygen. The concentration of NO remains constant along the tube because reaction (1) quickly regenerates NO from NO 2 , and the light intensity directly measures the concentration of atomic oxygen. The method is applied to give information on the rates of the reactions O + NO + M → NO 2 + M , O + O 2 + M → O 3 + M , O + SO 2 + M → SO 3 + M , etc. Some results are also presented for the effect on the disappearance of O of the following added gases: N 2 , A, CO 2 , H 2 , CO, N 2 O, C 6 H 8 , SO 3 , Fe(CO) 5 , H 2 O, O 3 , C 2 H 4 , Cl 2 and Br 2 . The rapid catalytic recombination of O by added Cl 2 is discussed in some detail.

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