Carbon Dioxide Content Of Air Research Articles

Effect of Supplementary Cyan Light to Deep Red and Royal Blue Range Wavelengths on the Seedling Period of Iceberg Lettuces

In this article, effect of cyan (≈500 nm) light on the plant growth as a supplementary light source to common deep red (≈660 nm) and royal blue (≈440) lights is examined. For this purpose, a 4-floor shelf was prepared containing Vernalia type iceberg lettuce (Lactuca sativa) seeds. Carbon dioxide content of air, soil moisture, air humidity, environment temperature, water, pH, electrical conductivity, fertilizer and nutrient contents were controlled at desired values; being same for the whole system. Second and third floors were lighted 18 hours a day, with the same photosynthetic photon flux density (PPFD) of 360 μmol m -2 s -1 . Third floor’s lighting was composed of 65% deep red and 35% royal blue lights. Second floor’s lighting was composed of 55% deep red, 25% royal blue and 20% cyan lights. First floor was lighted with sunlight, in order to make a comparison with natural lighting. Fourth floor contained the necessary control equipment. The experiment lasted for 15 days to analyse only the seedling period. The experiment results showed that, addition of cyan light to conventional red and blue grow lightings allowed the plants to grow 14% more by stem system. Also, cyan light provided a stronger root development and higher leaf area; which would indicate a higher product yield in the vegetative period. Keywords: Cyan light, artificial lighting, plant growth conditions, seedling period, lettuce, greenhouse efficiency, green light DOI : 10.7176/JBAH/9-10-11 Publication date :May 31 st 2019

Carbon dioxide and past Antarctic temperature linked

Antarctic ice core records indicate a strong connection between a rapid rise in temperature and a rapid increase in atmospheric carbon dioxide (CO2) that occurred during the last ice age. Ahn et al. analyzed the carbon dioxide content of air preserved in Antarctic ice cores covering a time period about 37 to 47 thousand years ago, during which Antarctica went through two warming events in the midst of an ice age. The authors show that approximately half of the CO2 increase that occurred during that period happened very quickly, over less than 200 years. Furthermore, this rapid rise in CO2 occurred nearly simultaneously with a rapid rise in Antarctic temperature. Improved knowledge of the past connection between CO2 and climate can help inform understanding of the feedback relationship between CO2 and climate today. (Geophysical Research Letters, doi:10.1029/2012GL053018, 2012)

Approximate equations for some acoustical and thermodynamic properties of standard air

This paper describes an investigation into the variation with humidity and carbon dioxide content in air of the speed of sound, characteristic impedance, specific heats, the ratio of specific heats, air density and the molar mass. The theoretical model is an approximation, which is based on standard air over a temperature range of 0 to 30 degrees Celsius and at a barometric pressure of 101.325kPa. Empirical equations for the computation of the above physical properties are provided together with uncertainty estimations.

Studies in phytotoxicity: The detection of incipient phytotoxic effects of sulphur preparations

AbstractIn a study of the relationship between carbon dioxide assimilation in the light, respiration in the dark, and temperature, the carbon dioxide content of air drawn over dwarf beans treated with lime sulphur or sulphur dust in light or darkness was continuously monitored coulometrically.Sulphur dust had only a negligible effect on carbon dioxide assimilation in the light or on respiration in the dark. Lime sulphur at 15 and 22°c also produced only small differences but at 30°c there were marked changes in net assimilation.Those treatments which caused changes in carbon dioxide assimilation in the light or respiration in the dark were directly associated with the degree of damage estimated visually. The method may be valuable for the detection of phytotoxic effects of other fungicides and insecticides.

Laser action in human breath and its use for monitoring the carbon dioxide content of air.

Laser action has been obtained in exhaled human breath at reduced pressure. The system, which is basically a nitrogen-carbon dioxide laser, has been used to determine the CO2 content of exhaled human breath over the range 1-6% CO2. Suggestions are made for possible applications.

Transpiration and Stomatal Opening with Changes in Carbon Dioxide Content of the Air

Increasing the carbon dioxide content of air reduces the transpiration rate of corn and sorghum plants and, to a lesser extent, of cotton, soybean, and tomato plants by causing the stomata to close. Closure of corn and sorghum stomata occurred when the concentrations of carbon dioxide were 2000 and 3000 parts per million, respectively. Cotton, soybean, and tomato stomata did not close completely at concentrations of carbon dioxide up to 4000 parts per million.

The Case for Independence of Administrative Agencies

T HE nature of the administrative machinery required for a regulatory purpose is determined by the relation of the nature of the problem to be handled to the policy to be pursued. For example, the problem may be to prescribe and maintain standards for a commodity moving in interstate commerce. The place of origin, the route of movement, the points of concentration, the technical matters of measuring the commodity and determining standards, and similar factors will govern construction of the administrative machinery to administer such standards. Administration of grain standards, inspection of meat, enforcement of requirements on milk, and like activities illustrate this type of problem. Standards can be stated with precision, violations or noncompliance can be ascertained with a high degree of certainty, and the law can be enforced through modified police methods. Standards may be determined by legislative action or by administrative action under legislative delegation, but in either case they will be based on the objective determinations of experts. A similar type of problem may appear in the regulation of structures and machinery for compliance with standards of health and safety. Such standards may be highly objective, having to do with the quality and strength of materials, measurable factors of temperature, humidity, carbon dioxide content of air, light, sanitary facilities, standard guards for types of machinery, and so on. The construction of machinery for enforcement of such standards is controlled by the location of the objects to be inspected, their density within a given region, the number of distinct types of inspection to be made at each location. This type of problem appears in the enforcement of protective labor legislation by state departments of labor using factory inspectors.

Points from Foregoing Letters

THE results of research on the carbon dioxide content of air under various conditions, carried out immediately prior to his death by Prof. J. S. Haldane, together with Dr. R. H. Makgill, are outlined by Prof. J. B. S. Haldane. The influence of height above ground, vegetation, seasons, soil, sea, city surroundings, etc., is indicated. The simplicity and rapidity of the method devised may render it useful in other fields, for example, for distinguishing, in meteorological observations, between bodies of air of different origin.