22,637 research outputs found

    Bactericidal effect of corona discharges in atmospheric air

    Get PDF
    The present paper explores the possibilities of using impulsive and steady-state corona discharges for bio-decontamination operations. A high tension tubular corona electrode was stressed with positive or negative dc voltage with magnitude up to 26 kV, and a grounded mesh was used as an opposite electrode. Different operational regimes of this corona generator were investigated for the production of ozone in air flow and the inactivation of microorganisms. The test microorganisms used in this work were Escherichia coli and Staphylococcus aureus, populations of which were seeded onto agar plates. These bacterial plates were located behind the grounded mesh electrode to assess bactericidal efficacy. The results show that corona discharges have a strong bactericidal effect, for example positive flashing corona discharges were able to reduce populations of the test microorganism by 94% within a 30-60 sec time interval. Negative steady-state corona discharges also produce noticeable bactericidal effect, reducing population of E. coli and S. aureus by more than 97% within 120 sec energisation interval. The bactericidal efficiency of different corona discharge modes and its correlation with ozone levels produced by these discharges is discussed. The results obtained in this work will help in the design and development of compact plasma systems for environmental application

    The equations of motion for moist atmospheric air

    Full text link
    How phase transitions affect the motion of moist atmospheric air remains controversial. In the early 2000s two distinct differential equations of motion were proposed. Besides their contrasting formulations for the acceleration of condensate, the equations differ concerning the presence/absence of a term equal to the rate of phase transitions multiplied by the difference in velocity between condensate and air. This term was interpreted in the literature as the "reactive motion" associated with condensation. The reasoning behind this "reactive motion" was that when water vapor condenses and droplets begin to fall the remaining gas must move upwards to conserve momentum. Here we show that the two contrasting formulations imply distinct assumptions about how gaseous air and condensate particles interact. We show that these assumptions cannot be simultaneously applicable to condensation and evaporation. "Reactive motion" leading to an upward acceleration of air during condensation does not exist. The "reactive motion" term can be justified for evaporation only; it describes the downward acceleration of air. We emphasize the difference between the equations of motion (i.e., equations constraining velocity) and those constraining momentum (i.e., equations of motion and continuity combined). We show that, owing to the imprecise nature of the continuity equations, consideration of total momentum can be misleading and that this led to the "reactive motion" controversy. Finally, we provide a revised and generally applicable equation for the motion of moist air.Comment: 11 pages, two figure

    Radio Emission in Atmospheric Air Showers: First Measurements with LOPES-30

    Get PDF
    When Ultra High Energy Cosmic Rays interact with particles in the Earth's atmosphere, they produce a shower of secondary particles propagating toward the ground. LOPES-30 is an absolutely calibrated array of 30 dipole antennas investigating the radio emission from these showers in detail and clarifying if the technique is useful for largescale applications. LOPES-30 is co-located and measures in coincidence with the air shower experiment KASCADE-Grande. Status of LOPES-30 and first measurements are presented.Comment: Proceedings of ARENA 06, June 2006, University of Northumbria, U

    Состояние атмосферного воздуха в пределах Оренбургской области

    Get PDF
    Статья посвящена анализу качества атмосферного воздуха в пределах Оренбургской области. Выявлены основные закономерности загрязнения атмосферного воздуха Оренбургской области.The article is devoted to analysis of the quality of atmospheric air in the Orenburg region. Analyzed the main regularities of pollution of atmospheric air in the Orenburg region

    Analysis of atmospheric air pollution of Ukrainian towns

    Get PDF
    Статтю присвячено опису актуального питання забруднення атмосферного повітря міст України. Забруднення атмосферного повітря являє більшу загрозу для людини, ніж забруднення води, тому що від забруднення повітря неможливо врятуватись. Тому, можна зробити висновок, що у сучасних умовах питання забруднення атмосферного повітря великих міст достатньо серйозне.The article is devoted to description of topical problem of atmospheric air pollution of Ukrainian towns. Pollution оf atmospheric air is very dangerous to people. It is more dangerous than pollution оf water, because to save from air pollution impossibly. Sо, can do the conclusion: problem of atmospheric air pollution of big towns is very serious in contemporary condition

    MULTIPLE CORRELATION MODEL FOR ESTABLISHING THE ASSOCIATION BETWEEN ATMOSPHERIC AIR POLLUTION AND MORBIDITY

    Get PDF
    A characteristics of atmospheric air pollution during the period from 1980 till 1992 in the town of Beloslav, a settlement located in the immediate proximity of Devnya industrial complex was prepared. The following parameters were examined: dust, sulphur dioxide, sulphuric acid, hydrogen sulphide, nitric oxides, ammonia, chlorine, and hydrogen fluoride. Annual indexes of pollution presented according to the Canadian Indexing System exceeded considerably the hygienic standards concerning most atmospheric air pollutants. During the whole period of observation the total index varied between 3,22 and 8,28 one unit being the standard. The morbidity rate of the population according to the registration files for children and adults was analyzed, too. Multiple correlation and step regression analyses were applied to follow-up the influence of the atmospheric air pollution on the morbidity. There were statistically reliable correlation dependences between the atmospheric air pollution and the diseases of the respiratory, nervous, alimentary and other systems

    Technology Needs Assessment of an Atmospheric Observation System for Multidisciplinary Air Quality/Meteorology Missions, Part 2

    Get PDF
    The technology advancements that will be necessary to implement the atmospheric observation systems are considered. Upper and lower atmospheric air quality and meteorological parameters necessary to support the air quality investigations were included. The technology needs were found predominantly in areas related to sensors and measurements of air quality and meteorological measurements

    Atmospheric Air Pollution and Monitoring

    Get PDF
    Indoor air quality (IAQ) is an important aspect in building design due to its effect on human health and wellbeing. Generally, people spend about 90% of their time indoors where they are exposed to chemicals, particulate matters, biological contaminants and possibly carcinogens. In particular, the air quality at hospitals carries with it risks for serious health consequences for medical staff as well as patients and visitors. This book is a study of atmospheric air pollution and presents ways we can reduce its impacts on human health. It discusses tools for measuring IAQ as well as analyzes IAQ in closed buildings. It is an important documentation of air quality and its impact on human health

    ANALYSIS OF THE CLIMATIC FEATURES OF THE REGIONS OF THE PRIMARY APPLICATION OF THE SYSTEMS FOR PRODUCING WATER FROM THE ATMOSPHERIC AIR

    Get PDF
    The object of research is the thermal and humidity processes occurring during artificial cooling of atmospheric air to the dew point temperature in the evaporators of refrigeration machines of the compression and absorption type. This study solves the problem of finding energy efficient heat and humidity modes for cooling atmospheric air to the dew point temperature in regions with a shortage of water resources and high solar installations. It is shown that practically in all considered climatic zones with a shortage of water resources, the process of obtaining water from atmospheric air is most energetically expended in the winter period of the year, and the most energetically efficient - in the summer period. In the summer period of the year, the specific energy consumption is numerically comparable in the cooling temperature range from 5 °C to 15 °C. It is also shown that the application of the technology of night radiation will create a reserve of natural cold for additional cooling of condensers of refrigerating machines of various types during the entire period of operation. The area of practical use of the research results: compression and absorption refrigeration machines operating in systems for obtaining water from atmospheric air and taking into account seasonal changes in the thermal and humidity parameters of atmospheric air. An innovative technological product: energy-efficient systems for obtaining water from atmospheric air based on refrigeration machines of the compression and absorption type, which also work with the help of solar radiation. Scope of application of the innovative technological product: systems for supplying the population with drinking and process water, mainly in areas with a shortage of water resources

    Why isolated streamer discharges hardly exist above the breakdown field in atmospheric air

    Full text link
    We investigate streamer formation in the troposphere, in electric fields above the breakdown threshold. With fully three-dimensional particle simulations, we study the combined effect of natural background ionization and of photoionization on the discharge morphology. In previous investigations based on deterministic fluid models without background ionization, so-called double-headed streamers emerged. But in our improved model, many electron avalanches start to grow at different locations. Eventually the avalanches collectively screen the electric field in the interior of the discharge. This happens after what we call the `ionization screening time', for which we give an analytical estimate. As this time is comparable to the streamer formation time, we conclude that isolated streamers are unlikely to exist in fields well above breakdown in atmospheric air.Comment: Changed citation information. 6 pages, 4 figures, Geophysical Research Letters, Vol. 40, 2417-2422, 201
    corecore