DECOMPOSITION PRESSURES OF FERRIC SULPHATE AND ALUMINUM SULPHATE

1960 ◽  
Vol 38 (11) ◽  
pp. 2196-2202 ◽  
Author(s):  
N. A. Warner ◽  
T. R. Ingraham
Keyword(s):  
Gas Phase ◽  
Static System ◽  
Ferric Sulphate ◽  
Kcal Mole ◽  
Aluminum Sulphate ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
Mercury Manometer ◽  
Decomposition Pressure ◽  
Gas Pressures

The gas pressures over samples of anhydrous ferric sulphate and anhydrous aluminum sulphate have been measured in a static system, using a mercury manometer in which the exposed surface was covered with a flexible Pyrex bellows. The calculated ΔH for the decomposition of Fe2(SO4)3 was +135.4 kcal/mole. It was not possible to calculate the ΔH for the Al2(SO4)3 decomposition, because a discrete aluminum oxide with singular thermodynamic properties was not obtained.In the Fe2(SO4)3 system, the fraction of SO3 in the gas phase was found to be almost constant over the range of temperature and pressure changes used in the study.At any given temperature, the decomposition pressure over a ferric sulphate sample is greater than that over an aluminum sulphate sample, thus indicating that preferential decomposition of ferric sulphate should be thermodynamically feasible in mixtures of ferric sulphate and aluminum sulphate.

scholarly journals Assessment of Piezoelectric Sensors for the Acquisition of Steady Melt Pressures in Polymer Extrusion

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 66
Author(s):  
Sónia Costa ◽  
Paulo Teixeira ◽  
José Covas ◽  
Loic Hilliou
Keyword(s):  
Polymer Processing ◽  
Piezoelectric Transducers ◽  
Piezoelectric Sensors ◽  
Flow Curves ◽  
Signal Drift ◽  
Temperature And Pressure ◽  
Pressure Independent ◽  
Pressure Changes ◽  
Different Levels ◽  
Slit Die

Piezoelectric sensors have made their way into polymer processing and rheometry applications, in particular when small pressure changes with very fast dynamics are to be measured. However, no validation of their use for steady shear rheometry is available in the literature. Here, a rheological slit die was designed and constructed to allow for the direct comparison of pressure data measured with conventional and piezoelectric transducers. The calibration of piezoelectric sensors is presented together with a methodology to correct the data from the inherent signal drift, which is shown to be temperature and pressure independent. Flow curves are measured for polymers showing different levels of viscoelasticity. Piezoelectric slit rheometry is validated and its advantage for the rheology of thermodegradable materials with viscosity below 100 Pa·s is highlighted.

scholarly journals Compensation of phase drifts caused by ambient humidity, temperature and pressure changes for continuously operating interferometers

2019 ◽  
Vol 14 (11) ◽  
pp. P11016-P11016
Author(s):  
K.J. Brunner ◽  
J. Knauer ◽  
J. Meineke ◽  
M. Stern ◽  
M. Hirsch ◽  
...  
Keyword(s):  
Ambient Humidity ◽  
Temperature And Pressure ◽  
Pressure Changes

Epidural versus subdural spinal cord cooling: cerebrospinal fluid temperature and pressure changes

2000 ◽  
Vol 70 (1) ◽  
pp. 222-227 ◽  
Author(s):  
Sven A Meylaerts ◽  
Cor J Kalkman ◽  
Peter de Haan ◽  
Marjolein Porsius ◽  
Michael J.H.M Jacobs
Keyword(s):  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Fluid Temperature ◽  
Temperature And Pressure ◽  
Pressure Changes

POLYMÉRISATION PAR LES RAYONS-X DU CHLORURE DE VINYLE À L'ÉTAT DE VAPEUR

1963 ◽  
Vol 41 (6) ◽  
pp. 1578-1587 ◽  
Author(s):  
Jan A. Herman ◽  
Pierre M. Hupin
Keyword(s):  
Activation Energy ◽  
Gas Phase ◽  
Average Molecular Weight ◽  
Negative Temperature ◽  
Solid Polymer ◽  
X Rays ◽  
Kcal Mole ◽  
Rate Of Polymerization ◽  
G Value ◽  
Termination Process

The polymerization of vinyl chloride in the gas phase by X rays gives a solid polymer of 1140 average molecular weight. The G value of monomer disappearance varies from 100 to 400 and depends on pressure and temperature. From the measure of the rate of polymerization it was possible to deduce the activation energy of the chain propagation steps: 2.5 kcal/mole, and that of the hindered termination process: 7.4 kcal/mole. The negative temperature co-efficient of the polymerization is explained by the importance of this hindered termination process.

scholarly journals Pressure dependent low temperature kinetics for CN + CH3CN: competition between chemical reaction and van der Waals complex formation

2016 ◽  
Vol 18 (22) ◽  
pp. 15118-15132 ◽  
Author(s):  
Chantal Sleiman ◽  
Sergio González ◽  
Stephen J. Klippenstein ◽  
Dahbia Talbi ◽  
Gisèle El Dib ◽  
...  
Keyword(s):  
Low Temperature ◽  
Complex Formation ◽  
Gas Phase ◽  
Rate Coefficient ◽  
Flow Reactor ◽  
Slow Flow ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Low Temperature Kinetics ◽  
Temperature And Pressure

The gas phase reaction between the CN radical and acetonitrile CH3CN was investigated experimentally with a CRESU apparatus and a slow flow reactor as well as theoretically to explore the temperature and pressure dependence of its rate coefficient from 354 K down to 23 K.

Subcutaneous tissue gas space pressure during superficial isobaric counterdiffusion

1979 ◽  
Vol 47 (1) ◽  
pp. 224-227 ◽  
Author(s):  
J. R. Cowley ◽  
C. Allegra ◽  
C. J. Lambertsen
Keyword(s):  
Gas Phase ◽  
Subcutaneous Tissue ◽  
Inert Gas ◽  
Maximum Pressure ◽  
Tissue Pressure ◽  
Phase Development ◽  
New Zealand White Rabbits ◽  
Gas Space ◽  
Pressure Changes ◽  
Mean Time

Changes in subcutaneous tissue pressure caused by N2O-He, 1-ATA isobaric counterdiffusion gas phase development were measured. Only the ears of New Zealand White rabbits were subjected to counterdiffusion. The rabbits breathed a mixture of 80% N2O-20% O2 while their ears alone were surrounded by He and the rest of their bodies continued to be surrounded by air. Subcutaneous pressure changes were transmitted to the transducer-recorded system via a fluid-filled subcutaneous needle. When the gas phase developed in subcutaneous tissue, pressure rose and a maximum pressure (Pmax) was reached. Pmax in the counterdiffused ear was 48 +/- 10 (SD) Torr, and mean time to reach Pmax was 75 +/- 10 (SD) min. The findings are discussed in relation to the pathological processes of isobaric inert gas counterdiffusion.

The gas-phase photochemistry and thermal decomposition of glyoxylic acid

1985 ◽  
Vol 63 (2) ◽  
pp. 542-548 ◽  
Author(s):  
R. A. Back ◽  
S. Yamamoto
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Absorption Spectrum ◽  
Gas Phase ◽  
Singlet State ◽  
Glyoxylic Acid ◽  
Static System ◽  
First Order ◽  
Increasing Temperature ◽  
Homogeneous Formation

The photolysis of glyoxylic acid vapour has been studied at five wavelengths, 382, 366, 346, 275, and 239 nm, and pressures from about 1 to 6 Torr, at a temperature of 355 K. Major products were CO2 and CH2O, initially formed in almost equal amounts, while minor products were CO and H2. Except at 382 nm, the system was complicated by the rapid secondary photolysis of CH2O. Three primary processes are suggested, each involving internal H-atom transfer followed by dissociation.The absorption spectrum is reported and shows the three distinct absorption systems. A finely-structured spectrum from about 320 to 400 nm is attributed to a transition to the first excited π* ← n+ singlet state; a more diffuse absorption ranging from about 290 nm to a maximum at 239 nm is assigned to the π* ← n− state, while a much stronger absorption beginning below 230 nm is attributed to the π* ← π transition. Product ratios vary with wavelength and depend on which excited state is involved.The thermal decomposition was studied briefly in a static system at temperatures from 470 to 710 K and pressures from 0.4 to 8 Torr. Major products were again CO2 and CH2O, but the latter was always less than stoichiometric. First-order rate constants for the apparently homogeneous formation of CO2 are described by Arrhenius parameters log A (s−1) = 7.80 and E = 30.8 kcal/mol. Carbon monoxide and H2 were minor products, and the CO/CO2 ratio increased with increasing temperature and showed some surface enhancement at lower temperatures. The SF6-sensitized thermal decomposition of glyoxylic acid, induced by a pulsed CO2 laser, was briefly studied, with temperatures estimated to be in the 1100–1600 K range, and the CO/CO2 ratio increased with increasing temperature, continuing the trend observed in the static system.

scholarly journals Compilation and evaluation of gas phase diffusion coefficients of halogenated organic compounds

2018 ◽  
Vol 5 (7) ◽  
pp. 171936 ◽  
Author(s):  
Wenjun Gu ◽  
Peng Cheng ◽  
Mingjin Tang
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Input Parameter ◽  
Empirical Method ◽  
Trace Gas ◽  
Temperature And Pressure ◽  
Organic Halogens ◽  
Semi Empirical ◽  
Method Show ◽  
Good Agreement

Organic halogens are of great environmental and climatic concern. In this work, we have compiled their gas phase diffusivities (pressure-normalized diffusion coefficients) in a variety of bath gases experimentally measured by previous studies. It is found that diffusivities estimated using Fuller's semi-empirical method agree very well with measured values for organic halogens. In addition, we find that at a given temperature and pressure, different molecules exhibit very similar mean free paths in the same bath gas, and then propose a method to estimate mean free paths in different bath gases. For example, the pressure-normalized mean free paths are estimated to be 90, 350, 90, 80, 120 nm atm in air (and N 2 /O 2 ), He, argon, CO 2 and CH 4 , respectively, with estimated errors of around ±25%. A generic method, which requires less input parameter than Fuller's method, is proposed to calculate gas phase diffusivities. We find that gas phase diffusivities in He (and air as well) calculated using our method show fairly good agreement with those measured experimentally and estimated using Fuller's method. Our method is particularly useful for the estimation of gas phase diffusivities when the trace gas contains atoms whose diffusion volumes are not known.

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