Synthetic Atmosphere Research Articles

Comparison of the Chromotropic Acid and Pararosaniline Methods for Measuring Formaldehyde Concentrations of Pressed-Wood Product Emissions

Formaldehyde concentrations of particleboard emissions in special measuring chambers were determined by both the chromotropic acid and pararosaniline methods, and the results were compared. Airborne and formalin-based calibration methods were compared also. An additional experiment was done to consider the possibility that aspects of the measuring system other than the calibration could bias results obtained from either analytical method. Synthetic formaldehyde atmospheres were substituted for pressed-wood products in the measuring chambers, and the concentrations were measured by both the chromotropic acid and pararosaniline methods. Formaldehyde concentrations determined by the chromotropic and pararosaniline methods agreed both on synthetic formaldehyde atmospheres and on emissions from five lots of particleboard from four different manufacturers.

Absolute continuum energy distributions in Be stars

The photoelectric spectrophotometry of nine Be stars is performed. Their monochromatic absolute magnitudes derived in the wavelength range λλ3200–8000 A are presented. The energy distribution curves obtained are calibrated for effective temperatures with the aid of the synthetic stellar atmospheres.

A kilometer pathlength fourier-transform infrared system for the study of trace pollutants in ambient and synthetic atmospheres

A Fourier-transform infrared (FT-i.r.) system operable at pathlengths up to 2 km has been constructed for the detection and measurement of trace contaminants in the ambient atmosphere and in controlled smog formation studies. The long optical path is achieved by the use of an eight-mirror multiple reflection cell with a 22.5-m base path. The design, construction and use of this novel foldedpath optical system are described in detail. In preliminary ambient air measurements at Riverside, California, during the period August–October, 1976, ppb concentrations of formaldehyde, nitric acid, formic acid and ammonia (in addition to O 3 and PAN) were measured in ambient air.

The Effects of Residual Magnetism on the Corrosion Fatigue Properties of Type 410 Stainless Steel Compressor Blades

Abstract Residual magnetism is beneficial in improving the corrosion fatigue strength of Type AISI-410 stainless steel compressor blades tested in a synthetic sea water atmosphere. The corrosion fatigue strength of magnetized blades is improved 56% and survival time is increased 357% as compared with non-magnetized blades. The improvement is attributed to a reduction in the rate at which dislocations cross slip to broaden slip planes which are preferentially attacked by the corrosion media. X-ray diffraction studies confirm an interaction of dislocations and magnetic domain walls.

Scale Growth during Re‐heating Cycles

AbstractPure iron, low carbon steel, medium carbon Mn‐steel and MnMo‐steel were studied in view of their high temperature corrosion behaviour in various gases. The gases used were: Oxygen, steam, carbon dioxide, air and five synthetic atmospheres, similar to those obtained by the combustion of sulphur‐free fuel oil and town gas. In order to obtain possible characteristic differences of behaviour isothermal experiments were made as well as experiments with temperature cyling. In the first case temperatures were 700 and 1200°C while in the second case temperatures were cycled between 500 and 1200°C. There are different degrees of agreement between the two experimental techniques, but in most cases it is possible to predict scaling behaviour for either type of experiment. It is possible to establish an “equivalent time” as a reference parameter for the comparison of temperature cycles from different furnaces.

Synthetic Hydrogen-containing Ultramarine Phases

Abstract Hydrogen was analyzed on synthetic sulfur-containing sodalite-type sodium aluminosilicates. Specimens synthesized from the NaAlSiO4-Na2S system in a H2 or N2 atomsphere or in a N2-S2 atmosphere contained hydrogens which were introduced by ion-exchange during water-washing. Specimens synthesized from the same system in H2S-containing atmospheres also contained hydrogens introduced from the synthetic atmosphere. The latter specimens had the formula: Na8Al6-Si6O24S·xH2S·yS, which was characterized by a constant number of sodium ions (eight per unit cell), whereas the former contained variable numbers of sodium ions according to the duration of water-washing. A difference in correlation between the sulfur content and the lattice constant was observed between these two series of specimens, indicating different manners of existence of the hydrogen.

Eye irritation as a biological indicator of photochemical reactions in the atmosphere

Studies involving the quantitation of eye irritation produced by experimental exposure of humans to synthetic atmospheres are discussed. The principal methods used are panel measurements of intensity, threshold, or response delay. Advantages and difficulties of each method are reviewed, as well as characteristics of the data generated and appropriate means of manipulating the data. Evidence regarding the possible chemical identity of irritants in photochemical smog is discussed, leading to the conclusion that not all observed eye irritation is accounted for by additive effect of formaldehyde, acrolein, and peroxyacyl nitrates. Implications of the findings for air pollution control policies are considered. As one of the undesirable manifestations of photochemical smog, eye irritation has been the subject of a number of studies in recent years. This article reviews several of these studies with particular reference to those aspects relevant to air pollution research and air pollution control policy.

Zur bestimmung der absoluten feuchte durch messung der absorption in den atmosphärischen wasserdampfbanden

The possibility of describing the absorption of radiation in the near and middle infrared by the water vapor bands of the atmosphere with relations identical in form to that arrived at in synthetic atmospheres (6) will here be examined. Only two intensities are necessary to determine the amount of absorbing material between the source and detector after suitable calibration. The application of universal absorption relations (equivalent widths) will give results with systematic errors due to the impossibility of measuring directly the continuum without absorption in the free atmosphere. From the results of this work the humidity near the ground can now be measured. One important application of this “optical method” in contrast to the classical methods is that the humidity at very low meteorological temperatures can be measured. The measurement of humidity in the upper troposphere and the lower stratosphere will be discussed.

Infrared Transmission of Synthetic Atmospheres* V Absorption Laws for Overlapping Bands

Although Lambert’s law Tν=e−kνw presumably applies to the absorption of gases in the infrared, the experimentally observed transmission Tν′ cannot be expressed by a simple relation of this type. It is observed, however, that in regions where the atmospheric carbon dioxide and water vapor absorption bands overlap Tν′(CO2+H2O)=Tν′(CO2) · Tν′(H2O) provided the total pressure P is constant. It is found that the total absorption ∫Aνdν for a synthetic atmospheric sample containing water vapor, carbon dioxide, and nitrogen can be expressed as ∫Aνdν=∫Aν(H2O)dν+∊∫Aν(CO2)dν, where ∫Aν(H2O)dν and ∫Aν(CO2)dν are given by the empirical relations obtained in earlier studies in the present series and ∊ is a fraction, which can be expressed in terms of the total absorption by water vapor.

Infrared Transmission of Synthetic Atmospheres* II Absorption by Carbon Dioxide

The total absorption ∫Aνdν has been determined for the CO2 bands at 15, 5.2, 4.8, 4.3, 2.7, 2.0, 1.6, and 1.4μ under stimulated atmospheric conditions. The absorber concentrations w ranged from 1 to 1000 atmos cm of CO2 for the strong bands and from 100 to 8600 atmos cm for the weak bands. Nitrogen was added to give total pressures ranging up to atmospheric; the pressure effects of oxygen were found to be similar to those of nitrogen. The observed data can be satisfactorily represented by two types of empirical relations.(1)For small values of total absorption,∫Aνdν=cw12(P+p)k;(2)For large values of total absorption,∫Aνdν=C+D Logw+K Log(P+p),where w is the CO2 absorber concentration, p is the CO2 partial pressure, and P is the total pressure. Values of the constants c, k, C, D, and K are given for each region of characteristic absorption. The present results are compared with those obtained in earlier studies. The use of the empirical relations in calculating atmospheric absorption is discussed.

Infrared Transmission of Synthetic Atmospheres* III Absorption by Water Vapor

The total absorption ∫Aνdν has been measured for the water vapor bands at 6.3, 3.2, 2.7, 1.87, 1.38, 1.1, and 0.94μ under simulated atmospheric conditions. The water vapor absorber concentrations studied ranged from 0.004 to 3.8 cm of precipitable water. Nitrogen was added to give total pressures up to atmospheric; the effects of nitrogen and oxygen on total absorption were found to be similar. The experimental data can be satisfactorily represented by two types of empirical relations:(1)For small values of total absorption,∫Aνdν=cw12(P+p)k;(2)For large values of total absorption,∫Aνdν=C+D Logw+K Log(P+p),where w is the H2O absorber concentration, p is the H2O partial pressure, and P is the total pressure. Values of the empirically determined constants c, k, C, D, and K are given for each of the spectral regions of characteristic absorption. The results are compared with those of other experimentalists.

Fluorescence as a Means of Identifying Smog Markings on Plants

The leaf markings that result from smog appear to fluoresce distinctively under ultraviolet radiation. This observation has been checked by comparing the response to ultraviolet radiation of sensitive plants exposed to actual smog, to synthetic atmospheres, and to a variety of cultural conditions. If further work confirms the results of these studies, the bright pale blue fluorescence of smog-marked leaves will provide the first objective means of assessing the responsibility of smog for vegetation damage.

Synthetic atmospheres studied

Synthetic atmospheres studied

The Effects of Synthetic Atmospheres of Hydrogen and Oxygen upon Animal Life

Aboqt ten years ago experiments on the effects of synthetic atmospheres on animal life were begun at McPherson College. The original purpose of the experiments was to determine the duration of animal life in pure unadulterated oxygen. It was found that animals lived from two to five days in oxygen, thus proving the necessity of the presence of some other gas which does not support life. Experiments were then undertaken to find a satisfactory substitute for nitrogen and a number of the inert gases were tried with the satisfying result of finding a mixture superior to air. This was a combination of helium and oxygen.

A laboratory study of the atmospheric corrosion of metals. Part I.—The Corrosion of copper in certain synthetic atmospheres, with particular reference to the influence of sulphur dioxide in air of various relative humidities

A laboratory study of the atmospheric corrosion of metals. Part I.—The Corrosion of copper in certain synthetic atmospheres, with particular reference to the influence of sulphur dioxide in air of various relative humidities