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Sample records for seti microwave observing

  1. NASA-SETI microwave observing project: Targeted Search Element (TSE)

    Science.gov (United States)

    Webster, L. D.

    1991-01-01

    The Targeted Search Element (TSE) performs one of two complimentary search strategies of the NASA-SETI Microwave Observing Project (MOP): the targeted search. The principle objective of the targeted search strategy is to scan the microwave window between the frequencies of one and three gigahertz for narrowband microwave emissions eminating from the direction of 773 specifically targeted stars. The scanning process is accomplished at a minimum resolution of one or two Hertz at very high sensitivity. Detectable signals will be of a continuous wave or pulsed form and may also drift in frequency. The TSE will possess extensive radio frequency interference (RFI) mitigation and verification capability as the majority of signals detected by the TSE will be of local origin. Any signal passing through RFI classification and classifiable as an extraterrestrial intelligence (ETI) candidate will be further validated at non-MOP observatories using established protocol. The targeted search will be conducted using the capability provided by the TSE. The TSE provides six Targeted Search Systems (TSS) which independently or cooperatively perform automated collection, analysis, storage, and archive of signal data. Data is collected in 10 megahertz chunks and signal processing is performed at a rate of 160 megabits per second. Signal data is obtained utilizing the largest radio telescopes available for the Targeted Search such as those at Arecibo and Nancay or at the dedicated NASA-SETI facility. This latter facility will allow continuous collection of data. The TSE also provides for TSS utilization planning, logistics, remote operation, and for off-line data analysis and permanent archive of both the Targeted Search and Sky Survey data.

  2. SETI - The microwave search problem and the targeted search approach

    Science.gov (United States)

    Seeger, C. L.; Wolfe, J. H.

    1985-01-01

    The targeted search component of the NASA SETI program is limited to time sharing in the usual fashion on existing large radio telescopes. Unless the consequences of this restriction are compensated by increased capability in the SETI electronic systems, an undesirable loss in sensitivity must be accepted in order to prevent a more costly and humanly unattractive lengthening of the projected five-year observing program to a duration of some decades.

  3. Recent SETI observations at Arecibo

    Science.gov (United States)

    Tarter, J. C.; Duquet, R. T.; Clark, T. A.; Lesyna, L.

    1983-05-01

    During 1980 and 1981, the 305-m radio telescope at the Arecibo Observatory in Puerto Rico was used to conduct a high resolution search for narrowband signals from the direction of 210 nearby solar type stars and 5 OH masers. For each star at least 4 MHz of bandwidth surrounding the 21-cm HI line and/or the 18-cm OH lines was studied with a spectral resolution of 5.5 Hz in both right and left circular polarization. The formal limit of sensitivity achieved during the course of this search varied depending upon the particular receivers available. In all cases the search could have detected a narrow band transmitter of power comparable to the Arecibo planetary radar, had any such been transmitting on the frequencies searched during the time of observation out to the distance of the farthest target star. As in previous searches, the number of "false alarms" encountered was far greater than predicted on the basis of Gaussian noise statistics. A small number of stars have exhibited signals which cannot immediately be explained in terms of astrophysical or man-made sources and deserve re-observation. This is typical of the results of previous non-real-time searches and does not yet constitute the detection of an ETI.

  4. Strategic considerations in SETI, and a microwave approach. [Search for ExtraTerrestrial Intelligence

    Science.gov (United States)

    Seeger, C. L.

    1977-01-01

    Plausible options in the search for extraterrestrial intelligence (SETI), and the need to reserve a suitable portion of the EM (microwave) spectrum for SETI research, are discussed. Reasons for selection of a portion of the spectrum, specifically the 'water hole' near 1.5 GHz in the terrestrial microwave window (1-25 GHz), are presented, and competition with various emitters for that band (existing satellite downlink transmissions) is discussed. SETI search policies and options are summarized in a table. Speculative considerations guiding initial phases of the SETI pursuit are discussed.

  5. Novel Optical SETI Observations of Three Exoplanets

    Science.gov (United States)

    Welsh, Barry; Vallerga, John; Kotze, Marissa; Wheatley, Jonathan

    2018-01-01

    We report on observations of three nearby stars (Trappist-1, GJ 422 and Wolf 1061) that possess exoplanets located in their respective habitable zones to search for optical signals generated by an advanced alien civilization. Using the photon data collected with the Berkeley Visible Image Tube attached to the 10m Southern African Large Telescope, we searched for very high amplitude events in the pulse height distributions that statistically could only be produced by non-astrophysical means such as an optical laser used for communications purposes.Assuming that a purported ET civilization has access to an orbiting 10m mirror and an optical laser to send signals over the three sight-lines to Earth, we derive upper limits to the output power of their l lasers which might be used for inter-stellar communication.

  6. SETI OBSERVATIONS OF EXOPLANETS WITH THE ALLEN TELESCOPE ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Harp, G. R.; Richards, Jon; Tarter, Jill C.; Dreher, John; Jordan, Jane; Shostak, Seth; Smolek, Ken; Kilsdonk, Tom; Wilcox, Bethany R.; Wimberly, M. K. R.; Ross, John; Barott, W. C.; Ackermann, R. F.; Blair, Samantha [SETI Institute, Mountain View, CA 94043 (United States)

    2016-12-01

    We report radio SETI observations on a large number of known exoplanets and other nearby star systems using the Allen Telescope Array (ATA). Observations were made over about 19000 hr from 2009 May to 2015 December. This search focused on narrowband radio signals from a set totaling 9293 stars, including 2015 exoplanet stars and Kepler objects of interest and an additional 65 whose planets may be close to their habitable zones. The ATA observations were made using multiple synthesized beams and an anticoincidence filter to help identify terrestrial radio interference. Stars were observed over frequencies from 1 to 9 GHz in multiple bands that avoid strong terrestrial communication frequencies. Data were processed in near-real time for narrowband (0.7–100 Hz) continuous and pulsed signals with transmitter/receiver relative accelerations from −0.3 to 0.3 m s{sup −2}. A total of 1.9 × 10{sup 8} unique signals requiring immediate follow-up were detected in observations covering more than 8 × 10{sup 6} star-MHz. We detected no persistent signals from extraterrestrial technology exceeding our frequency-dependent sensitivity threshold of 180–310 × 10{sup −26} W m{sup −2}.

  7. OPTICAL SETI OBSERVATIONS OF THE ANOMALOUS STAR KIC 8462852

    Energy Technology Data Exchange (ETDEWEB)

    Schuetz, Marlin; Vakoch, Douglas A. [METI International, 100 Pine Street, Suite 1250, San Francisco, CA 94111-5235 (United States); Shostak, Seth; Richards, Jon, E-mail: dvakoch@meti.org [Center for SETI Research, SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States)

    2016-07-01

    To explore the hypothesis that KIC 8462852's aperiodic dimming is caused by artificial megastructures in orbit, rather than a natural cause such as cometary fragments in a highly elliptical orbit, we searched for electromagnetic signals from KIC 8462852 indicative of extraterrestrial intelligence. The primary observations were in the visible optical regime using the Boquete Optical SETI Observatory in Panama. In addition, as a recommended preparatory exercise for the possible future detection of a candidate signal, three of six observing runs simultaneously searched radio frequencies at the Allen Telescope Array in California. No periodic optical signals greater than 67 photons m{sup −2} within a time frame of 25 ns were seen. If, for example, any inhabitants of KIC 8462852 were targeting our solar system with 5 MJ laser pulses, locally illuminating an approximately 3 au diameter disk, the signal could have been detected at the Boquete Observatory. The limits on narrowband radio signals were 180–300 Jy Hz at 1 and 8 GHz, respectively. While the power requirement for a detectable, isotropic narrowband radio transmission from KIC 8462852 is quite high, even modest targeting on the part of the putative extraterrestrials can lower this power substantially.

  8. PiHi Observations at the ATA, Conventional and Unconventional SETI

    Science.gov (United States)

    Harp, Gerald; Wilcox, B.; Arbunich, J.; Blair, S.; Backus, P. R.; Tarter, J. C.; Shostak, S.; Jordan, J.; Kilsdonk, T.; Ackermann, R. F.; Ross, J.; ATA Team

    2010-01-01

    Many radio SETI searches focus on the frequency range where the HI (1.42 GHz) and OH lines (1.6-1.7 GHz) lines are landmarks delineating the water hole This is only a small fraction of the terrestrial microwave window (TMW) from 1-10 GHz. This survey occurs near the center of the TMW at 4.462336275 GHz or π times the HI frequency. We call this the PiHI ("pie high") survey. The inspiration for PiHI observations comes from Carl Sagan in his book, Contact. This survey builds upon and extends a previous survey at PiHI (Blair, D. G. et al. (1992), MNRAS, 257, 105) with greater sensitivity, resolution, and coverage. We survey the nearest 94 main sequence stars in the HabCat catalog (Turnbull, M. C. and Tarter, J. C. (2003), ApJS, 145, 181) with spectral classes between F9 and G7 (max. radius 62 pc). The ATA's flexibility allows simultaneous measurements of targeted observations on stars (with beamformers) and 1° FOV "blind” observations of the areas around target stars (with imaging correlator). The targeted observations are carried out with a high resolution (0.7 Hz) spectrometer and integration times on the order of 200 s. The spectral imaging correlator measures a 50 x 50 grid of points with 3 kHz spectral resolution. This survey shows several signals of minor interest were discovered, though none of the signals reported are continuously "on,” which is an important characteristic for the positive identification of an ETI signal. The ATA has been funded through generous grants from the Paul G. Allen Family Foundation, the SETI Institute, UC Berkeley, the National Science Foundation (Grant No. 0540599), Sun Microsystems, Xilinx, Nathan Myhrvold, Greg Papadopoulos, and other corporations and individual donors.

  9. Observational program options and system requirements for the search for extraterrestrial intelligence /SETI/

    Science.gov (United States)

    Billingham, J.; Wolfe, J. H.; Edelson, R. E.; Gulkis, S.; Sadin, S. R.

    1978-01-01

    The possibility that intelligent life may be widespread in the universe is now being investigated. A formula for estimating the number of coexisting communicative civilizations has been developed by Drake. A good way of conducting a search for extraterrestrial intelligence (SETI) is to examine the microwave window of the electromagnetic spectrum for narrow-band signals which such civilizations may be transmitting. Two specific search strategies are described. Both employ existing antennas equipped with sophisticated multichannel spectrum analyzers and pattern recognition devices. The Ames Research Center proposal is a high sensitivity, high-resolution search of nearby promising stars and selected sky areas in the 'water hole' (1400-1727 MHz). The Jet Propulsion Laboratory proposal is for a survey of most of the sky over a significant portion of the free-space microwave window at lower sensitivities and resolutions. The approaches are complementary and both are being pursued. The consummation of these programs could achieve one of the most profound discoveries in the history of human civilization, or at least will show the way to future efforts.

  10. SETI science working group report

    Science.gov (United States)

    Drake, F.; Wolfe, J. H.; Seeger, C. L.

    1984-01-01

    This report covers the initial activities and deliberations of a continuing working group asked to assist the SETI Program Office at NASA. Seven chapters present the group's consensus on objectives, strategies, and plans for instrumental R&D and for a microwave search for extraterrestrial in intelligence (SETI) projected for the end of this decade. Thirteen appendixes reflect the views of their individual authors. Included are discussions of the 8-million-channel spectrum analyzer architecture and the proof-of-concept device under development; signal detection, recognition, and identification on-line in the presence of noise and radio interference; the 1-10 GHz sky survey and the 1-3 GHz targeted search envisaged; and the mutual interests of SETI and radio astronomy. The report ends with a selective, annotated SETI reading list of pro and contra SETI publications.

  11. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  12. Mutual help in SETIs

    Science.gov (United States)

    Melia, F.; Frisch, D. H.

    1985-06-01

    Techniques to establish communication between earth and extraterrestrial intelligent beings are examined analytically, emphasizing that the success of searches for extraterrestrial intelligence (SETIs) depends on the selection by both sender and receiver of one of a few mutually helpful SETI strategies. An equation for estimating the probability that an SETI will result in the recognition of an ETI signal is developed, and numerical results for various SETI strategies are presented in tables. A minimum approach employing 10 40-m 20-kW dish antennas for a 30-yr SETI in a 2500-light-year disk is proposed.

  13. Manifestation of intelligence implications for SETI

    Science.gov (United States)

    Kuiper, T. B. H.

    1986-01-01

    The objectives of the SETI projects are discussed. Life, intelligence, and sapience are defined in order to characterize the phenomena. Dissipation and coherence are useful characteristics for detection. Consideration is given to electromagnetically observable phenomena, in particular spatial coherence.

  14. SETI in the Ecliptic Plane

    Science.gov (United States)

    Conn Henry, Richard; Kilston, S.; Shostak, S.

    2008-05-01

    The strong advantages of SETI searches in the ecliptic plane have been pointed out by Kilston, Shostak, and Henry (2008). In our poster we show one possible history of civilizations in the galaxy, from birth, through galactic colonization, up to death - and even beyond. Should this scenario be correct, the pattern suggests that the best hope for success in SETI is exploration of the possibility that there are a few extremely ancient but non-colonizing civilizations; civilizations that, aeons ago, detected the existence of Earth (oxygen, and hence life) and of its Moon (stabilizing Earth's rotation) via observations of transits of the Sun (hence, ecliptic, which is stable over millions of years [Laskar et al. 2004]), and have been beaming voluminous information in our direction ever since, in their faint hope (now realized) that a technological "receiving” species would appear. To maintain such a targeted broadcast would be extremely cheap for an advanced civilization. A search of a swath centered on our ecliptic plane should easily find such civilizations, if they exist. We hope to carry out such a search, using the Allen Telescope Array. http://henry.pha.jhu.edu/poster.SETI.pdf References: Kilston, Steven; Shostak, Seth; & Henry, Richard Conn; "Who's Looking at You, Kid?: SETI Advantages near the Ecliptic Plane," AbSciCon 2008, April 14-17, Santa Clara, CA.; Laskar, J., et al., A&A 428, 261, 2004 This work was supported by Maryland Space Grant Consortium.

  15. Formal and nonformal SETI education programs

    Science.gov (United States)

    Bhathal, Ragbir

    2001-08-01

    Frank Drake's experiment on the search for extraterrestrial intelligence in 1960 not only generated a new field of observational astronomy but also produced spin-offs in the fields of education and the social science. SETI education programs in formal and non-formal educational institutions provide a powerful tool for educating the public and students about humanity's most profound question: are we alone in the universe? This paper discusses SETI educational programs in both formal and non-formal settings.

  16. Passive Polarimetric Microwave Signatures Observed Over Antarctica

    Science.gov (United States)

    WindSat satellite-based fully polarimetric passive microwave observations, expressed in the form of the Stokes vector, were analyzed over the Antarctic ice sheet. The vertically and horizontally polarized brightness temperatures (first two Stokes components) from WindSat are shown to be consistent w...

  17. Searching for sentience: SETI today

    Science.gov (United States)

    Shostak, G. Seth

    2003-04-01

    For more than four decades, a small group of researchers has sought to find evidence of extraterrestrial intelligence in situ, by detecting microwave signals that would betray its existence. Despite the failure to find these signals so far, there is continued and even accelerated effort to press the search. Recent advances include greater emphasis on experiments at optical wavelengths, and the construction of a new radio telescope that is deliberately designed for such reconnaissance. In addition to these instrumental improvements, several strategies have been proposed that might better the chances of "looking in the right place, at the right time". This review of the current state of SETI research concludes with a speculative look at the nature of the sought-for extraterrestrials, and when it is likely we might find them.

  18. Microwave Observations of Precipitation and the Atmosphere

    Science.gov (United States)

    Staelin, David H.; Rosenkranz, Philip W.

    2004-01-01

    This research effort had three elements devoted to improving satellite-derived passive microwave retrievals of precipitation rate: morphological rain-rate retrievals, warm rain retrievals, and extension of a study of geostationary satellite options. The morphological precipitation-rate retrieval method uses for the first time the morphological character of the observed storm microwave spectra. The basic concept involves: 1) retrieval of point rainfall rates using current algorithms, 2) using spatial feature vectors of the observations over segmented multi-pixel storms to estimate the integrated rainfall rate for that storm (cu m/s), and 3) normalization of the point rain-rate retrievals to ensure consistency with the storm-wide retrieval. This work is ongoing, but two key steps have been completed: development of a segmentation algorithm for defining spatial regions corresponding to single storms for purposes of estimation, and reduction of some of the data from NAST-M that will be used to support this research going forward. The warm rain retrieval method involved extension of Aquai/AIRS/AMSU/HSB algorithmic work on cloud water retrievals. The central concept involves the fact that passive microwave cloud water retrievals over approx. 0.4 mm are very likely associated with precipitation. Since glaciated precipitation is generally detected quite successfully using scattering signatures evident in the surface-blind 54- and 183-GHz bands, this new method complements the first by permitting precipitation retrievals of non-glaciated events. The method is most successful over ocean, but has detected non-glaciated convective cells over land, perhaps in their early formative stages. This work will require additional exploration and validation prior to publication. Passive microwave instrument configurations for use in geostationary orbit were studied. They employ parabolic reflectors between 2 and 4 meters in diameter, and frequencies up to approx.430 GHz; this

  19. SETI as an educational tool

    Science.gov (United States)

    Vaile, R. A.

    SETI offers an extraordinary catalyst in our search for a better education. While the glamour of movie images increased the general public awareness of the term "SETI", we are challenged to improve the level of public understanding of the fundamental scientific and technological issues involved in SETI. It is also critical to keep in mind the reality of human existence. No country seems entirely at peace, whether one considers cultural, trade, military, or heritage issues; no country seems content with the breadth and standards of education for following generations. However, SETI requires generations to participate across cultures, and this long-term human involvement must be sustained through both education and communication across many disciplines and different cultures. For both these major roles, SETI appears to offer a tantalising range and depth, both in educational tools, and in superb tests of communication skills. This paper considers the educational influence of roles evoked by SETI issues. We will briefly consider the range in expertise needed in SETI, the means of improving the public SETI awareness, and mechanisms through which such education may explore the consequences of any SETI result (whether judged as successful or not). Examples of the use of SETI in formal secondary and University education are briefly reviewed.

  20. Innovative SETI by the KLT

    Science.gov (United States)

    Maccone, C.

    SETI searches are, by definition, the extraction of very weak radio signals out of the cosmic background noise. When SETI was born in 1959, it was "natural" to attempt this extraction by the only detection algorithm well known at the time: the Fourier Transform (FT). In fact: 1) SETI radio astronomers had adopted the viewpoint that a candidate ET signal would necessarily be a sinusoidal carrier, i.e. a very narrow-band signal. Over such a narrow band, the background noise is necessarily white. And so, the basic assumption behind the FT that the background noise must be white was "perfectly matched" to SETI for the next fifty years! 2) In addition, the Americans, J. W. Cooley and J. W. Tukey discovered in April 1965 that all the FT computations could be speeded up to N*ln(N) (rather than N2) (N is the number of numbers to be processed) by their own Fast Fourier Transform (FFT). Then, SETI radio astronomers all over the world gladly and unquestioningly adopted the new FFT forever. In 1983, however, the French SETI radio astronomer, François Biraud, dared to challenge this view (ref. [6]). He argued that we only can make guesses about ET's telecommunication systems, and that the shifting trend on Earth was from narrow-band to wide-band telecommunications. Thus, a new transform, other than the FFT, was needed that could detect signals over both narrow and wide bands, regardless of the colored noise distribution over any finite bandwidth. Such a transform had actually been pointed out as early as 1946 by the Finn mathematician, Kari Karhunen, and the French mathematician, Michel Loève, and is thus named KLT for them. In conclusion, François Biraud suggested to "look for the unknown in SETI" by adopting the KLT rather than the FFT. The same ideas were reached independently by this author also, and starting 1987, he too was "preaching the KLT": first at the SETI Institute, then (since 1990) at the Italian CNR (now called INAF) SETI facilities at Medicina, near Bologna

  1. Microwave observations for forecasting energetic particles from the Sun

    Science.gov (United States)

    Zucca, Pietro; Nuñez, Marlon; Klein, Karl-Ludwig; Malandraki, Olga; Pavlos, Evgenios; Miteva, Rositsa

    2017-04-01

    Solar energetic particles (SEPs), especially protons and heavy ions, are a major space weather hazard when they impact spacecraft and the terrestrial atmosphere. Forecasting schemes have been developed, which use earlier signatures of particle acceleration to predict the arrival of solar protons and ions in the space environment of the Earth. In this study, we investigate the advantages of microwave observations for forecasting the SEP occurrence and SEP energy spectrum. The UMASEP scheme forecasts the occurrence and the importance of a SEP event based on combined observations of soft X-rays, their time derivative, and protons above 10 MeV at geosynchronous orbit. We explore the possibility to replace the derivative of the soft X-ray time history by the microwave time history in the UMASEP scheme. For the forecast of the SEP energy spectrum, we investigate if the hardness or softness of the proton spectrum in interplanetary space can be predicted from the shape of the microwave spectrum. The technique developed by Chertok et al (2009) is to use the ratio of peak microwave flux densities near 9 and 15 GHz as a predictor. Here, we tested this scheme over solar cycle 23 and 24. A detailed analysis of the results including limitations the methods are presented. We conclude that microwave patrol observations improve SEP forecasting schemes that employ soft X-rays. High-quality microwave data available in real time appear as a significant addition to our ability to predict SEP occurrence and their energy spectrum. Acknowledgements: This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 637324

  2. The SERENDIP 2 SETI project: Current status

    Science.gov (United States)

    Bowyer, C. S.; Werthimer, D.; Donnelly, C.; Herrick, W.; Lampton, M.

    1991-01-01

    Over the past 30 years, interest in extraterrestrial intelligence has progressed from philosophical discussion to rigorous scientific endeavors attempting to make contact. Since it is impossible to assess the probability of success and the amount of telescope time needed for detection, Search for Extraterrestrial Intelligence (SETI) Projects are plagued with the problem of attaining the large amounts of time needed on the world's precious few large radio telescopes. To circumvent this problem, the Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations (SERENDIP) instrument operates autonomously in a piggyback mode utilizing whatever observing plan is chosen by the primary observer. In this way, large quantities of high-quality data can be collected in a cost-effective and unobtrusive manner. During normal operations, SERENDIP logs statistically significant events for further offline analysis. Due to the large number of terrestrial and near-space transmitters on earth, a major element of the SERENDIP project involves identifying and rejecting spurious signals from these sources. Another major element of the SERENDIP Project (as well as most other SETI efforts) is detecting extraterrestrial intelligence (ETI) signals. Events selected as candidate ETI signals are studied further in a targeted search program which utilizes between 24 to 48 hours of dedicated telescope time each year.

  3. Risk and value analysis of SETI

    Science.gov (United States)

    Billingham, J.

    1990-01-01

    This paper attempts to apply a traditional risk and value analysis to the Search for Extraterrestrial Intelligence--SETI. In view of the difficulties of assessing the probability of success, a comparison is made between SETI and a previous search for extraterrestrial life, the biological component of Project Viking. Our application of simple Utility Theory, given some reasonable assumptions, suggests that SETI is at least as worthwhile as the biological experiment on Viking.

  4. SETI Programs at the University of California, Berkeley

    Science.gov (United States)

    Korpela, E. J.; Siemion, A. V. P.; Werthimer, D.; Korff, J. V.; Gautham, A.; Cobb, J.; Lebofsky, M.; Dexter, M.; MacMahon, D.; Wright, S.

    2014-03-01

    I describe recent SETI efforts by the University of California, Berkeley SETI Research center and efforts to be undertaken in the near future. In addition to our well known SETI@home (Korpela 2011) and Astropulse (Von Korff et al. 2013) public participation SETI survey projects, we have performed several targeted obsevations of different object classes. These include 1) Observations between 1.1 and 1.9 GHz of planetary systems idenfied by Kepler as containing earthlike planets in or near the habitable zones. (Siemion et al. 2013) 2) Wide-band Arecibo observations of 112 sky locations where the Astropulse project has identified strong µs duration dispersed radio pulses. 3) Observations of Kepler identified planetary systems at times when two planets would appear to be in conjuction when viewed from Earth. We plan a future campaign to simultaneously observe known planetary systems at radio, optical and IR wavelengths. We have also continued to advance our instrumentation. We are currently building the sixth generation of our SERENDIP (Siemion et al. 2011, Korpela et al. 2011) series of SETI instrumentation for installation at both Arecibo and GBT. SERENDIP VI will utilize an FPGA based polyphase filter bank course spectrometer feeding 8 or more GPU based compute nodes. The Arecibo version of this spectrometer will be capable of providing thresholded 1Hz resolution spectra of all seven beams of the 320 MHz bandwidth Arecibo L-band Feed Array in dual polarization. A separate front end will be available to allow up to 2.2 GHz of bandwidth in dual polarization from single pixel receivers. The Green Bank version of this spectrometer will utilize the single pixel front end. We are invesitating the possibility of simultaneous back end stages operating on the same or minimal processed data, for example, we could support simulataneous detection of fast extragalactic radio bursts (Thornton et al. 2013) by adding additional compute nodes. We are also developing new instruments

  5. SETI in the new Millennium

    Science.gov (United States)

    Morison, Ian

    2006-08-01

    SETI, the Search for Extraterrestrial Intelligence, has now been actively pursued for close to 50 years without success. However, this does not imply that we are alone in the Milky Way galaxy for, although most astronomers now agree that intelligent civilizations are far less common than were once thought, we cannot say that there are none. But it does mean that they are likely to be further away from us and, as yet, we have only seriously searched a tiny region of our galaxy. It will not be until the 2020s that an instrument, now on the drawing board, will give us the capability to detect radio signals of realistic power from the whole galaxy. It is also possible that light, rather than radio, might be the communication carrier chosen by an alien race, but optical-SETI searches seeking out pulsed laser signals have only just begun.

  6. Evolutionary contingency and SETI revisited

    Science.gov (United States)

    Cirkovic, Milan M.

    2014-07-01

    The well-known argument against the Search for ExtraTerrestrial Intelligence (SETI) due to George Gaylord Simpson is re-analyzed almost half a century later, in the light of our improved understanding of preconditions for the emergence of life and intelligence brought about by the ongoing "astrobiological revolution". Simpson's argument has been enormously influential, in particular in biological circles, and it arguably fueled the most serious opposition to SETI programmes and their funding. I argue that both proponents and opponents of Simpson's argument have occasionally mispresented its core content. Proponents often oversimplify it as just another consequence of biological contingency, thus leaving their position open to general arguments limiting the scope of contingency in evolution (such as the recent argument of Geerat Vermeij based on selection effects in the fossil record). They also tend to neglect that the argument has been presented as essentially atemporal, while referring to entities and processes that are likely to change over time; this has become even less justifiable as our astrobiological knowledge increased in recent years. Opponents have failed to see that the weaknesses in Simpson's position could be removed by restructuring of the argument; I suggest one way of such restructuring, envisioned long ago in the fictional context by Stanislaw Lem. While no firm consensus has emerged on the validity of Simpson's argument so far, I suggest that, contrary to the original motivation, today it is less an anti-SETI argument, and more an astrobiological research programme. In this research programme, SETI could be generalized into a platform for testing some of the deepest assumptions about evolutionary continuity and the relative role of contingency versus convergence on unprecedented spatial and temporal scales.

  7. Half a century of SETI in the USSR and Russia

    Science.gov (United States)

    Gindilis, Lev; Gurvits, Leonid

    SETI. This outlook will be based on the advances of relevant scientific and technological areas, especially in astronomy. These developments are characterised by invention of new ultra-sensitive instruments and ability to process enormous amounts of experimental (observing) data, unthinkable in the recent past. All that would create a new basis for the continuation of SETI in the foreseeable future.

  8. Evolution of Life and SETI (Evo-SETI)

    Science.gov (United States)

    Maccone, Claudio

    When SETI scientists will be able to discover a signal or just some signs of an Extra-Terrestrial (ET) Civilization, those ETs should turn out to be technologically advanced at least as much as Humans, if not more, or much more so. Comparing the technological level of two different Civilizations is then a key issue in SETI. But at the moment we only know about the development of life on Earth over the last 3.5 billion years. We thus need to mathematically model the evolution of life on Earth (RNA to Humans) and then apply our results to other extra-solar planets to find out “where they stand” along their evolution of life. In a series of recent papers and in a book (refs. [1] through [4]) this author introduced a new statistical model embracing SETI, Darwinian Evolution and Human History into a unified statistical picture and concisely called Evo-SETI (Evolution & SETI). The relevant mathematical instruments are: 1) The statistical generalization of the Drake equation yielding the number N of communicating ET civilizations in the Galaxy. Assuming that each input variable in the Drake equation was a random variable, rather than just a pure number, N was shown to follow the lognormal probability distribution having as mean value the sum of the input mean values, and as variance the sum of the input variances (ref. [1]). 2) Geometric Brownian Motion (GBM), the stochastic process representing Evolution as the stochastic increase of the number of Species living on Earth over the last 3.5 billion years. This GBM is well-known in the mathematics of finances (Black-Sholes models). Its main features are that its probability density function (pdf) is a lognormal pdf, and its mean value is either an increasing, or, more rarely (as in the Mass Extinctions of the past) a decreasing exponential of the time. 3) The probability distributions known as b-lognormals, i.e. lognormals starting at a certain positive instant b>0 rather than at the origin. These b-lognormals were then

  9. Positive consequences of SETI before detection

    Science.gov (United States)

    Tough, A.

    Even before a signal is detected, six positive consequences will result from the scientific search for extraterrestrial intelligence, usually called SETI. (1) Humanity's self-image: SETI has enlarged our view of ourselves and enhanced our sense of meaning. Increasingly, we feel a kinship with the civilizations whose signals we are trying to detect. (2) A fresh perspective: SETI forces us to think about how extraterrestrials might perceive us. This gives us a fresh perspective on our society's values, priorities, laws and foibles. (3) Questions: SETI is stimulating thought and discussion about several fundamental questions. (4) Education: some broad-gage educational programs have already been centered around SETI. (5) Tangible spin-offs: in addition to providing jobs for some people, SETI provides various spin-offs, such as search methods, computer software, data, and international scientific cooperation. (6) Future scenarios: SETI will increasingly stimulate us to think carefully about possible detection scenarios and their consequences, about our reply, and generally about the role of extraterrestrial communication in our long-term future. Such thinking leads, in turn, to fresh perspectives on the SETI enterprise itself.

  10. The Benefits of Adding SETI to the University Curriculum and What We Have Learned from a SETI Course Recently Offered at UCLA

    Science.gov (United States)

    Lesyna, Larry; Margot, Jean-Luc; Greenberg, Adam; Shinde, Akshay; Alladi, Yashaswi; Prasad MN, Srinivas; Bowman, Oliver; Fisher, Callum; Gyalay, Szilard; McKibbin, William; Miles, Brittany E.; Nguyen, Donald; Power, Conor; Ramani, Namrata; Raviprasad, Rashmi; Santana, Jesse

    2017-01-01

    We advocate for the inclusion of a full-term course entirely devoted to SETI in the university curriculum. SETI usually warrants only a few lectures in a traditional astronomy or astrobiology course. SETI’s rich interdisciplinary character serves astronomy students by introducing them to scientific and technological concepts that will aid them in their dissertation research or later in their careers. SETI is also an exciting topic that draws students from other disciplines and teaches them astronomical concepts that they might otherwise never encounter in their university studies. We have composed syllabi that illustrate the breadth and depth that SETI courses provide for advanced undergraduate or graduate students. The syllabi can also be used as a guide for an effective SETI course taught at a descriptive level.After a pilot course in 2015, UCLA formally offered a course titled "EPSS C179/279 - Search for Extraterrestrial Intelligence: Theory and Applications" in Spring 2016. The course was designed for advanced undergraduate students and graduate students in the science, technical, engineering, and mathematical fields. In 2016, 9 undergraduate students and 5 graduate students took the course. Students designed an observing sequence for the Arecibo and Green Bank telescopes, observed known planetary systems remotely, wrote a sophisticated and modular data processing pipeline, analyzed the data, and presented the results. In the process, they learned radio astronomy fundamentals, software development, signal processing, and statistics. The instructor believes that the students were eager to learn because of the engrossing nature of SETI. The students rated the course highly, in part because of the observing experience and the teamwork approach. The next offering will be in Spring 2017.See lxltech.com and seti.ucla.edu

  11. The SETI Interpreter Program (SIP). a Software Package for the SETI Field Tests

    Science.gov (United States)

    Olsen, E. T.; Lokshin, A.

    1983-01-01

    The SETI (Search for Extraterrestrial Intelligence) Interpreter Program (SIP) is an interactive software package designed to allow flexible off line processing of the SETI field test data on a PDP 11/44 computer. The user can write and immediately execute complex analysis programs using the compact SIP command language. The software utilized by the SETI Interpreter Program consists of FORTRAN - coded modules that are sequentially installed and executed.

  12. Jupiter's global ammonia distribution inferred from Juno Microwave Radiometer Observations

    Science.gov (United States)

    Li, Cheng; Ingersoll, Andrew; Ewald, Shawn; Oyafuso, Fabiano; Janssen, Michael

    2017-04-01

    The Juno microwave radiometer (Juno/MWR) has made several observations of Jupiter's atmosphere by measuring the thermal emission from pressure levels down to a few hundred bars. The main objective of Juno/MWR is to determine Jupiter's deep water abundance because water is the key to understand Jovian meteorology that we observe at the cloud level, and because the deep water abundance hints at a giant planet's volatile and heavy element history. Since ammonia is the major opacity source in the Juno/MWR channels, it is especially important to figure out the ammonia distribution before we can conclude anything on the water abundance. At this stage of our analysis, we have inverted a global map (vertical and latitudinal) of ammonia distribution from the observed brightness temperatures at six wavelengths using the Markov Chain Monte Carlo technique. This method fully calibrates error and explores a wide range of the parameter space to avoid falling into a local minimum. The robustness of the retrieval is explained by matching the features in the ammonia distribution with the features in the microwave spectra. We will also announce the initial result of the retrieval of water abundance using the same technique.

  13. The Ultimate Hacker: SETI Signals May Need to Be Decontaminated

    Science.gov (United States)

    Carrigan, Richard A., Jr.

    2004-06-01

    Biological contamination from space is a remote but recognized possibility. SETI signals might also contain harmful information. Some argue that a SETI signal could not contaminate a terrestrial computer because the idiosyncratic computer logic and code constitute an impenetrable firewall. Suggestions are given below on how to probe these arguments and decontaminate SETI signals.

  14. A Search for Brief Optical Flashes Associated with the SETI Target KIC 8462852

    Science.gov (United States)

    Abeysekara, A. U.; Archambault, S.; Archer, A.; Benbow, W.; Bird, R.; Buchovecky, M.; Buckley, J. H.; Byrum, K.; Cardenzana, J. V.; Cerruti, M.; hide

    2016-01-01

    The F-type star KIC8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon/sq m, is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.

  15. Passive microwave satellite snow observations for hydrologic applications

    Science.gov (United States)

    Vuyovich, Carrie M.

    Melting snow provides an essential source of water in many regions of the world and can also contribute to devastating, wide-scale flooding. The objective of this research was to investigate the potential for passive microwave remotely sensed data to characterize snow water equivalent (SWE) and snowmelt across diverse regions and snow regimes to improve snowmelt runoff estimation. The first step was to evaluate the current, empirically-based passive microwave SWE products compared to NOAA's operational SWE estimates from SNODAS across 2100 watersheds over eight years. The best agreement was found within basins in which maximum annual SWE is less than 200 mm, and forest fraction is less than 20%. Next, a sensitivity analysis was conducted to evaluate the microwave signal response to spatially distributed wet snow using a loosely-coupled snow-emission model. The results over an area approximately the size of a microwave pixel found a near-linear relationship between the microwave signal response and the percent area with wet snow present. These results were confirmed by evaluating actual wet snow events over a nine year period, and suggest that the microwave response provides the potential basis for disaggregating melting snow within a microwave pixel. Finally, a similar sensitivity analysis conducted in six watersheds with diverse landscapes and snow conditions confirmed the relationship holds at a basin scale. The magnitude of the microwave response to wet snow was compared to the magnitude of subsequent discharge events to determine if an empirical relation exists. While positive increases in brightness temperature (TB) correspond to positive increases in discharge, the magnitude of those changes is poorly correlated in most basins. The exception is in basins where snowmelt runoff typically occurs in one event each spring. In similar basins, the microwave response may provide information on the magnitude of spring runoff. Methods to use these findings to improve

  16. A Half-century of SETI Science

    Science.gov (United States)

    Shuch, H. Paul

    We begin our journey with a brief review of half a century of SETI science. The material in this introductory chapter is offered for the benefit of those educated laypersons whose enthusiasm for the Search for Extraterrestrial Intelligence exceeds their detailed knowledge of the relevant technologies. It is my hope that readers of this volume will better appreciate the material which follows if they first have a basic understanding of SETI concepts. Hence, I offer an overview, which is intended not to be exhaustive, but rather representative. Together, we will explore the nature of radio telescopes, experimental design strategies, SETI instrumentation, signal analysis, and the hallmarks of artificiality that allow us to differentiate between natural astrophysical emissions and intelligent interstellar transmissions. If you are already a technical specialist in these areas, feel free to bypass this introduction, and proceed directly to the subsequent chapters.

  17. Searching for Extraterrestrial Intelligence SETI Past, Present, and Future

    CERN Document Server

    Shuch, H Paul

    2011-01-01

    This book is a collection of essays written by the very scientists and engineers who have led, and continue to lead, the scientific quest known as SETI, the search for extraterrestrial intelligence. Divided into three parts, the first section, ‘The Spirit of SETI Past’, written by the surviving pioneers of this then emerging discipline, reviews the major projects undertaken during the first 50 years of SETI science and the results of that research. In the second section, ‘The Spirit of SETI Present’, the present-day science and technology is discussed in detail, providing the technical background to contemporary SETI instruments, experiments, and analytical techniques, including the processing of the received signals to extract potential alien communications. In the third and final section, ‘The Spirit of SETI Future’, the book looks ahead to the possible directions that SETI will take in the next 50 years, addressing such important topics as interstellar message construction, the risks and assump...

  18. A strategic 'viewfinder' for SETI research

    Science.gov (United States)

    Teodorani, Massimo

    2014-12-01

    One of the most important reasons why unsuccessful results have been obtained so far by the SETI Project is due to the fact that no sure targets to aim at have been available up-to the present state of research. All-sky surveys, even if very accurate and complete, might result to be time-consuming. SETI needs at least one effective 'viewfinder' in order that a true targeted research is carried out with a possible success. The best foundation to get this can be identified with the search for the evidence of extraterrestrial astro-engineering activity in form of the Dyson spheres predicted by theory. The existence of such stellar objects can be ascertained by finding the evidence of two main signatures in stars of solar spectral type: infrared excess and anomalous light curves due to transiting artificial objects. These are probably the most powerful viewfinders in order to allow SETI techniques for intelligent signal search to be aimed at more appropriate targets. This paper is not intended to be a research paper but rather a review paper whose goal is not to present calculations and/or operational research but rather to be a research proposal for a more focused research in SETI just using Dyson Spheres as crucial markers.

  19. New Small Satellite Capabilities for Microwave Atmospheric Remote Sensing: The Earth Observing Nanosatellite-Microwave (EON-MW)

    Science.gov (United States)

    Blackwell, W. J.

    2015-12-01

    Four nanosatellite advanced technology missions flying microwave radiometers for high-resolution atmospheric sensing are in varying stages of development. Microwave instrumentation is particularly well suited for implementation on a very small satellite, as the sensor requirements for power, pointing, and spatial resolution (aperture size) can be accommodated by a nanosatellite platform. The first mission, the Microsized Microwave Atmospheric Satellite (MicroMAS), was developed to demonstrate temperature sounding in nine channels near 118 GHz on a 3U CubeSat (10x10x34 cm; 4.25 kg). MicroMAS was recently released from the International Space Station (ISS) for a 100-day mission, and while an eventual transmitter failure prevented demonstration of the radiometer payload, all key spacecraft subsystems provided on-orbit data to validate performance. Two 3U CubeSat follow-on missions, MicroMAS-2 (12 channels near 90, 118, 183, and 206 GHz; cross-track scanning) and MiRaTA (12 channels near 60, 183, and 206 GHz; no scanning; GPSRO onboard), will launch in 2016 for further demonstration. Building upon this work, the Earth Observing Nanosatellite-Microwave mission is being formulated by MIT Lincoln Laboratory for the NOAA National Environmental Satellite, Data, and Information Service as part of the Polar Follow-On (PFO) budget request to extend JPSS for two more missions, and provides a means to mitigate the risk of a gap in continuity of weather observations. The PFO request aims to achieve robustness in the polar satellite system to ensure continuity of NOAA's polar weather observations. The baseline EON-MW design accommodates a scanning 22-channel high-resolution microwave spectrometer on a 12U (22x22x34 cm, 20 kg) CubeSat platform to provide data continuity with the existing AMSU and ATMS microwave sounding systems. EON-MW will nominally be launched into a sun-synchronous orbit for a two to three year mitigation mission in 2019 that will also extend technology

  20. Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions - 2002 Revision

    Science.gov (United States)

    SRD 116 NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions - 2002 Revision (Web, free access)   Critically evaluated transition frequencies for the molecular transitions detected in interstellar and circumstellar clouds are presented.

  1. Mathematical SETI Statistics, Signal Processing, Space Missions

    CERN Document Server

    Maccone, Claudio

    2012-01-01

    This book introduces the Statistical Drake Equation where, from a simple product of seven positive numbers, the Drake Equation is turned into the product of seven positive random variables. The mathematical consequences of this transformation are demonstrated and it is proven that the new random variable N for the number of communicating civilizations in the Galaxy must follow the lognormal probability distribution when the number of factors in the Drake equation is allowed to increase at will. Mathematical SETI also studies the proposed FOCAL (Fast Outgoing Cyclopean Astronomical Lens) space mission to the nearest Sun Focal Sphere at 550 AU and describes its consequences for future interstellar precursor missions and truly interstellar missions. In addition the author shows how SETI signal processing may be dramatically improved by use of the Karhunen-Loève Transform (KLT) rather than Fast Fourier Transform (FFT). Finally, he describes the efforts made to persuade the United Nations to make the central part...

  2. SETI turns 50: five decades of progress in the search for extraterrestrial intelligence

    Science.gov (United States)

    Tarter, J. C.; Agrawal, A.; Ackermann, R.; Backus, P.; Blair, S. K.; Bradford, M. T.; Harp, G. R.; Jordan, J.; Kilsdonk, T.; Smolek, K. E.; Richards, J.; Ross, J.; Shostak, G. S.; Vakoch, D.

    2010-09-01

    The 1959 Nature article by Giuseppe Cocconi and Phil Morrison1 provided the theoretical underpinnings for SETI, accompanied in 1960 by Project Ozma2, the first radio search for signals by Frank Drake at the National Radio Astronomy Observatory (NRAO). Well over 100 search programs have been conducted since that time, primarily at radio and optical wavelengths, (see www.seti.org/searcharchives) without any successful signal detection. Some have suggested that this means humans are alone in the cosmos. But that is far too strong a conclusion to draw from far too small an observational sampling. Instead of concluding that intelligent life on Earth is unique, it is more appropriate to note that in 50 years our ability to search for electromagnetic signals has improved by at least 14 orders of magnitude and that these improvements are still occurring at an exponential rate. At the SETI Institute we are in the process of reinventing the way we search in order to fully utilize these technological enhancements. We are now building the setiQuest community and we intend to get the world involved in making our searches better. We need to find ways to harness the intelligence of all Earthlings in order to better seek out extraterrestrial intelligence. If we do it right, we just might succeed, and we might also change how we see ourselves, and make our own world a better place.

  3. Dysonian SETI as a "Shortcut" to Detecting Habitable Planets

    Science.gov (United States)

    Wright, J. T.

    2016-12-01

    The search for habitable planets is ultimately motivated by the search for inhabited planets. On Earth, the most telling signature of life is that of humanity's technology. The Search for Extraterrestrial Intelligence (SETI) is thus the "ultimate" search for habitable planets.In 1960 two seminal papers in SETI were published, providing two visions for SETI. Giuseppe Cocconi and Philip Morrison's proposed detecting deliberate radio signals ("communication SETI"), while Freeman Dyson ("artifact SETI"), proposed detecting the inevitable effects of massive energy supplies and artifacts on their surroundings. While communication SETI has now had many career-long practitioners and major efforts, artifact SETI has, until recently, not been a vibrant field of study. The launch of the Kepler and WISE satellites have greatly renewed interest in the field, however, and the recent Breakthrough Listen Initiative has provided new motivation for finding good targets for communication SETI. I will discuss the progress of the Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies, including its justification and motivation, waste heat search strategy and first results, and the framework for a search for megastructures via transit light curves. The last of these led to the identification of KIC 8462852 (a.k.a. "Tabby's Star") as a candidate ETI host. This star, discovered by Boyajian and the Zooniverse Planet Hunters, exhibits several apparently unique and so-far unexplained photometric properties, and continues to confound natural explanation.

  4. Synergistic estimation of surface parameters from jointly using optical and microwave observations in EOLDAS

    Science.gov (United States)

    Timmermans, Joris; Gomez-Dans, Jose; Lewis, Philip; Loew, Alexander; Schlenz, Florian

    2017-04-01

    The large amount of remote sensing data nowadays available provides a huge potential for monitoring crop development, drought conditions and water efficiency. This potential however not been realized yet because algorithms for land surface parameter retrieval mostly use data from only a single sensor. Consequently products that combine different low-level observations from different sensors are hard to find. The lack of synergistic retrieval is caused because it is easier to focus on single sensor types/footprints and temporal observation times, than to find a way to compensate for differences. Different sensor types (microwave/optical) require different radiative transfer (RT) models and also require consistency between the models to have any impact on the retrieval of soil moisture by a microwave instrument. Varying spatial footprints require first proper collocation of the data before one can scale between different resolutions. Considering these problems, merging optical and microwave observations have not been performed yet. The goal of this research was to investigate the potential of integrating optical and microwave RT models within the Earth Observation Land Data Assimilation System (EOLDAS) synergistically to derive biophysical parameters. This system uses a Bayesian data assimilation approach together with observation operators such as the PROSAIL model to estimate land surface parameters. For the purpose of enabling the system to integrate passive microwave radiation (from an ELBARRA II passive microwave radiometer), the Community Microwave Emission Model (CMEM) RT-model, was integrated within the EOLDAS system. In order to quantify the potential, a variety of land surface parameters was chosen to be retrieved from the system, in particular variables that a) impact only optical RT (such as leaf water content and leaf dry matter), b) only impact the microwave RT (such as soil moisture and soil temperature), and c) Leaf Area Index (LAI) that impacts both

  5. Teaching Planetary Science as Part of the Search for Extraterrestrial Intelligence (SETI)

    Science.gov (United States)

    Margot, Jean-Luc; Greenberg, Adam H.

    2017-10-01

    In Spring 2016 and 2017, UCLA offered a course titled "EPSS C179/279 - Search for Extraterrestrial Intelligence: Theory and Applications". The course is designed for advanced undergraduate students and graduate students in the science, technical, engineering, and mathematical fields. Each year, students designed an observing sequence for the Green Bank telescope, observed known planetary systems remotely, wrote a sophisticated and modular data processing pipeline, analyzed the data, and presented their results. In 2016, 15 students participated in the course (9U, 5G; 11M, 3F) and observed 14 planetary systems in the Kepler field. In 2017, 17 students participated (15U, 2G; 10M, 7F) and observed 10 planetary systems in the Kepler field, TRAPPIST-1, and LHS 1140. In order to select suitable targets, students learned about planetary systems, planetary habitability, and planetary dynamics. In addition to planetary science fundamentals, students learned radio astronomy fundamentals, collaborative software development, signal processing techniques, and statistics. Evaluations indicate that the course is challenging but that students are eager to learn because of the engrossing nature of SETI. Students particularly value the teamwork approach, the observing experience, and working with their own data. The next offering of the course will be in Spring 2018. Additional information about our SETI work is available at seti.ucla.edu.

  6. The Order of the Dolphin: Origins of SETI

    Science.gov (United States)

    Temming, Maria; Crider, Anthony

    2016-01-01

    In 1961, the National Academy of Sciences organized a meeting on the search for extraterrestrial intelligence (SETI) at the National Radio Astronomy Observatory in Green Bank, West Virginia. The ten scientists who attended, including future SETI icons such as Frank Drake and Carl Sagan, represented a variety of scientific fields. At the conclusion of the meeting, the attendees adopted the moniker "The Order of the Dolphin," in honor of participant John Lilly's work on interspecies communication. Since this seminal meeting, researchers in each of the attendees' fields have contributed in some way to the search for intelligent life. This study investigates the circumstances that led to each attendee's invitation to Green Bank and explores SETI as the legacy of this meeting. We will focus in this talk on the SETI connections of two attendees, astronomer Otto Struve and physicist Philip Morrison, both in regards to their personal contributions to SETI and the influence of their work on subsequent SETI research. Specifically, we will examine proposals by Otto Struve for exoplanet discovery methods, and Philip Morrison for radio searches that laid the groundwork for modern SETI.

  7. Broad horizons SETI, SF and education

    Science.gov (United States)

    Griffiths, Martin

    2004-04-01

    Science fiction (SF) is often perceived as a ‘fringe’ form of entertainment that excites the socially challenged. This misperception detracts from the critical, scientific and interpretive nature of the genre which can be directed into science teaching at school and university levels as an innovative way of exploring the cultural background, politics, leitmotif and themes of society, science and their operation. One example is the ‘alien’ theme in SF; it is perceptually one of the driving factors in the search for extraterrestrial intelligence (SETI). Such a topic can become an introduction to current technology, the motives and politics of science and the sociological implications inherent in a confrontation with the ideal of man's uniqueness in the cosmos. When applied to the SETI, SF engenders a constructive convergence in studies such as biological determinism, the evolution of life, communication, interstellar travel and methods of contact, thus enriching the consideration of possible life in the cosmos. Adopting elements of SF in lifelong learning therefore enables informed, imaginative reflection and debate that educates, trains and instructs, broadening the potential of students and their future roles by invoking an analysis of vital public, scientific and humanistic fields.

  8. Applications of Land Surface Temperature from Microwave Observations

    Science.gov (United States)

    Land surface temperature (LST) is a key input for physically-based retrieval algorithms of hydrological states and fluxes. Yet, it remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observation...

  9. Identification of clay pans from AMSR-E passive microwave observations

    NARCIS (Netherlands)

    Vreugdenhil, M.; de Jeu, R.A.M.; Walker, J.P.

    2013-01-01

    A new methodology to derive the spatial distribution of clay pans from satellite microwave data is presented. Soil moisture has a different temporal signature in clay pans compared with other soils, which is directly reflected in the satellite-observed brightness temperatures. Three years of

  10. Assimilation of active and passive microwave observations for improved estimates of soil moisture and crop growth

    Science.gov (United States)

    An Ensemble Kalman Filter-based data assimilation framework that links a crop growth model with active and passive (AP) microwave models was developed to improve estimates of soil moisture (SM) and vegetation biomass over a growing season of soybean. Complementarities in AP observations were incorpo...

  11. Amplitude of the diurnal temperature cycle as observed by thermal infrared and microwave radiometers

    Science.gov (United States)

    Land surface temperature (LST) is a key input to physically-based retrieval algorithms of hydrological states and fluxes, and global measurements of LST are provided by many satellite platforms. Passive microwave (MW) observations offer an alternative to conventional thermal infrared (TIR) LST retri...

  12. SETI pioneers scientists talk about their search for extraterrestrial intelligence

    CERN Document Server

    Swift, David W.

    1990-01-01

    Why did some scientists decide to conduct a search for extraterrestrial intelligence (SETI)? What factors in their personal development predisposed them to such a quest? What obstacles did they encounter along the way? David Swift interviewed the first scientists involved in the search & offers a fascinating overview of the emergence of this modern scientific endeavor. He allows some of the most imaginative scientific thinkers of our time to hold forth on their views regarding SETI & extraterrestrial life & on how the field has developed. Readers will react with a range of opinions as broad as those concerning the likelihood of success in SETI itself. ''A goldmine of original information.''

  13. An optimal estimation algorithm to derive Ice and Ocean parameters from AMSR Microwave radiometer observations

    DEFF Research Database (Denmark)

    Pedersen, Leif Toudal; Tonboe, Rasmus T.; Høyer, Jacob

    robin reference dataset. Over open water the reference data is a co-location of satellite SST, ERA Interim re-analysis data and observed brightness temperatures. Over ice the reference data is a co-location of ERA Interim re-analysis data, and observed AMSR microwave brightness temperatures. Due...... to the nonlinearity of the radiative transfer equation we need an iterative approach to obtain the optimal estimate. The paper will demonstrate results of retrievals of SST and Sea Ice Concentration....

  14. Kurzweil's Singularity as a part of Evo-SETI Theory

    Science.gov (United States)

    Maccone, Claudio

    2017-03-01

    Ray Kurzweil's famous 2006 book "The Singularity Is Near" predicted that the Singularity (i.e. computers taking over humans) would occur around the year 2045. In this paper we prove that Kurzweil's prediction is in agreement with the "Evo-SETI" (Evolution and SETI)" mathematical model that this author has developed over the last five years in a series of mathematical papers published in both Acta Astronautica and the International Journal of Astrobiology.

  15. Assimilation of Precipitation Measurement Missions Microwave Radiance Observations With GEOS-5

    Science.gov (United States)

    Jin, Jianjun; Kim, Min-Jeong; McCarty, Will; Akella, Santha; Gu, Wei

    2015-01-01

    The Global Precipitation Mission (GPM) Core Observatory satellite was launched in February, 2014. The GPM Microwave Imager (GMI) is a conically scanning radiometer measuring 13 channels ranging from 10 to 183 GHz and sampling between 65 S 65 N. This instrument is a successor to the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI), which has observed 9 channels at frequencies ranging 10 to 85 GHz between 40 S 40 N since 1997. This presentation outlines the base procedures developed to assimilate GMI and TMI radiances in clear-sky conditions, including quality control methods, thinning decisions, and the estimation of, observation errors. This presentation also shows the impact of these observations when they are incorporated into the GEOS-5 atmospheric data assimilation system.

  16. AN OPPORTUNISTIC SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE (SETI) WITH THE MURCHISON WIDEFIELD ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Tingay, S. J.; Tremblay, C.; Walsh, A.; Urquhart, R. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia)

    2016-08-20

    A spectral line image cube generated from 115 minutes of MWA data that covers a field of view of 400 sq, deg. around the Galactic Center is used to perform the first Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array (MWA). Our work constitutes the first modern SETI experiment at low radio frequencies, here between 103 and 133 MHz, paving the way for large-scale searches with the MWA and, in the future, the low-frequency Square Kilometre Array. Limits of a few hundred mJy beam{sup −1} for narrowband emission (10 kHz) are derived from our data, across our 400 sq. deg. field of view. Within this field, 45 exoplanets in 38 planetary systems are known. We extract spectra at the locations of these systems from our image cube to place limits on the presence of narrow line emission from these systems. We then derive minimum isotropic transmitter powers for these exoplanets; a small handful of the closest objects (10 s of pc) yield our best limits of order 10{sup 14} W (Equivalent Isotropic Radiated Power). These limits lie above the highest power directional transmitters near these frequencies currently operational on Earth. A SETI experiment with the MWA covering the full accessible sky and its full frequency range would require approximately one month of observing time. The MWA frequency range, its southern hemisphere location on an extraordinarily radio quiet site, its very large field of view, and its high sensitivity make it a unique facility for SETI.

  17. SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Guillochon, James; Loeb, Abraham, E-mail: jguillochon@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-10-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)

  18. Observations of Ball-Lightning-Like Plasmoids Ejected from Silicon by Localized Microwaves

    Directory of Open Access Journals (Sweden)

    Michael Sztucki

    2013-09-01

    Full Text Available This paper presents experimental characterization of plasmoids (fireballs obtained by directing localized microwave power (<1 kW at 2.45 GHz onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity. The experimental diagnostics employed for the fireball characterization in this study include measurements of microwave scattering, optical spectroscopy, small-angle X-ray scattering (SAXS, scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS. Various characteristics of these plasmoids as dusty plasma are drawn by a theoretical analysis of the experimental observations. Aggregations of dust particles within the plasmoid are detected at nanometer and micrometer scales by both in-situ SAXS and ex-situ SEM measurements. The resemblance of these plasmoids to the natural ball-lightning (BL phenomenon is discussed with regard to silicon nano-particle clustering and formation of slowly-oxidized silicon micro-spheres within the BL. Potential applications and practical derivatives of this study (e.g., direct conversion of solids to powders, material identification by breakdown spectroscopy (MIBS, thermite ignition, and combustion are discussed.

  19. Estimating Sea Surface Salinity and Wind Using Combined Passive and Active L-Band Microwave Observations

    Science.gov (United States)

    Yueh, Simon H.; Chaubell, Mario J.

    2012-01-01

    Several L-band microwave radiometer and radar missions have been, or will be, operating in space for land and ocean observations. These include the NASA Aquarius mission and the Soil Moisture Active Passive (SMAP) mission, both of which use combined passive/ active L-band instruments. Aquarius s passive/active L-band microwave sensor has been designed to map the salinity field at the surface of the ocean from space. SMAP s primary objectives are for soil moisture and freeze/thaw detection, but it will operate continuously over the ocean, and hence will have significant potential for ocean surface research. In this innovation, an algorithm has been developed to retrieve simultaneously ocean surface salinity and wind from combined passive/active L-band microwave observations of sea surfaces. The algorithm takes advantage of the differing response of brightness temperatures and radar backscatter to salinity, wind speed, and direction, thus minimizing the least squares error (LSE) measure, which signifies the difference between measurements and model functions of brightness temperatures and radar backscatter. The algorithm uses the conjugate gradient method to search for the local minima of the LSE. Three LSE measures with different measurement combinations have been tested. The first LSE measure uses passive microwave data only with retrieval errors reaching 1 to 2 psu (practical salinity units) for salinity, and 1 to 2 m/s for wind speed. The second LSE measure uses both passive and active microwave data for vertical and horizontal polarizations. The addition of active microwave data significantly improves the retrieval accuracy by about a factor of five. To mitigate the impact of Faraday rotation on satellite observations, the third LSE measure uses measurement combinations invariant under the Faraday rotation. For Aquarius, the expected RMS SSS (sea surface salinity) error will be less than about 0.2 psu for low winds, and increases to 0.3 psu at 25 m/s wind speed

  20. Satellite observations of snow and ice with an imaging passive microwave spectrometer

    Science.gov (United States)

    Fisher, A. D.; Ledsham, B. L.; Rosenkranz, P. W.; Staelin, D. H.

    1976-01-01

    The scanning microwave spectrometer (SCAMS) on the Nimbus-6 satellite continuously maps the terrestrial surface with a resolution of about 150 km at 22.235 and 31.400 GHz. SCAMS observes at six angles besides nadir, yielding brightness temperatures which are a function of the distribution and character of various types of snow and ice, including microstructure and subsurface profiles in refractive index, loss (moisture or salinity), and temperature. Spectral signatures exhibiting interesting topographical structure have been observed. To aid in the interpretation of these data, a model was developed to describe the propagation of microwave intensity in a scattering medium characterized by three-dimensional random fluctuations of refractive index in addition to nonrandom variations in permittivity, temperature, and loss. The model combines Maxwell's equations in the Born approximation with radiative-transfer theory; this approach yields the variation of intensity with polarization, direction, and position.

  1. Monitoring soil moisture through assimilation of active microwave remote sensing observation into a hydrologic model

    Science.gov (United States)

    Liu, Qian; Zhao, Yingshi

    2015-08-01

    Soil moisture can be estimated from point measurements, hydrologic models, and remote sensing. Many researches indicated that the most promising approach for soil moisture is the integration of remote sensing surface soil moisture data and computational modeling. Although many researches were conducted using passive microwave remote sensing data in soil moisture assimilation with coarse spatial resolution, few researches were carried out using active microwave remote sensing observation. This research developed and tested an operational approach of assimilation for soil moisture prediction using active microwave remote sensing data ASAR (Advanced Synthetic Aperture Radar) in Heihe Watershed. The assimilation was based on ensemble Kalman filter (EnKF), a forward radiative transfer model and the Distributed Hydrology Soil Vegetation Model (DHSVM). The forward radiative transfer model, as a semi-empirical backscattering model, was used to eliminate the effect of surface roughness and vegetation cover on the backscatter coefficient. The impact of topography on soil water movement and the vertical and lateral exchange of soil water were considered. We conducted experiments to assimilate active microwave remote sensing data (ASAR) observation into a hydrologic model at two field sites, which had different underlying conditions. The soil moisture ground-truth data were collected through the field Time Domain Reflectometry (TDR) tools, and were used to assess the assimilation method. The temporal evolution of soil moisture measured at point-based monitoring locations were compared with EnKF based model predictions. The results indicated that the estimate of soil moisture was improved through assimilation with ASAR observation and the soil moisture based on data assimilation can be monitored in moderate spatial resolution.

  2. Abnormal Winter Melting of the Arctic Sea Ice Cap Observed by the Spaceborne Passive Microwave Sensors

    Directory of Open Access Journals (Sweden)

    Seongsuk Lee

    2016-12-01

    Full Text Available The spatial size and variation of Arctic sea ice play an important role in Earth’s climate system. These are affected by conditions in the polar atmosphere and Arctic sea temperatures. The Arctic sea ice concentration is calculated from brightness temperature data derived from the Defense Meteorological Satellite program (DMSP F13 Special Sensor Microwave/Imagers (SSMI and the DMSP F17 Special Sensor Microwave Imager/Sounder (SSMIS sensors. Many previous studies point to significant reductions in sea ice and their causes. We investigated the variability of Arctic sea ice using the daily and monthly sea ice concentration data from passive microwave observations to identify the sea ice melting regions near the Arctic polar ice cap. We discovered the abnormal melting of the Arctic sea ice near the North Pole even during the summer and the winter. This phenomenon is hard to explain only surface air temperature or solar heating as suggested by recent studies. We propose a hypothesis explaining this phenomenon. The heat from the deep sea in Arctic Ocean ridges and/or the hydrothermal vents might be contributing to the melting of Arctic sea ice. This hypothesis could be verified by the observation of warm water column structure below the melting or thinning arctic sea ice through the project such as Coriolis dataset for reanalysis (CORA.

  3. Lognormals for SETI, Evolution and Mass Extinctions

    Science.gov (United States)

    Maccone, Claudio

    2014-12-01

    In a series of recent papers (Refs. [1-5,7,8]) and in a book (Ref. [6]), this author suggested a new mathematical theory capable of merging Darwinian Evolution and SETI into a unified statistical framework. In this new vision, Darwinian Evolution, as it unfolded on Earth over the last 3.5 billion years, is defined as just one particular realization of a certain lognormal stochastic process in the number of living species on Earth, whose mean value increased in time exponentially. SETI also may be brought into this vision since the number of communicating civilizations in the Galaxy is given by a lognormal distribution (Statistical Drake Equation). Now, in this paper we further elaborate on all that particularly with regard to two important topics: The introduction of the general lognormal stochastic process L(t) whose mean value may be an arbitrary continuous function of the time, m(t), rather than just the exponential mGBM (t) =N0eμt typical of the Geometric Brownian Motion (GBM). This is a considerable generalization of the GBM-based theory used in Refs. [1-8]. The particular application of the general stochastic process L(t) to the understanding of Mass Extinctions like the K-Pg one that marked the dinosaurs' end 65 million years ago. We first model this Mass Extinction as a decreasing Geometric Brownian Motion (GBM) extending from the asteroid's impact time all through the ensuing 'nuclear winter'. However, this model has a flaw: the 'final value' of the GBM cannot have a horizontal tangent, as requested to enable the recovery of life again after this 'final extinction value'. That flaw, however, is removed if the rapidly decreasing mean value function of L(t) is the left branch of a parabola extending from the asteroid's impact time all through the ensuing 'nuclear winter' and up to the time when the number of living species on Earth started growing up again, as we show mathematically in Section 3. In conclusion, we have uncovered an important generalization

  4. Mediterranean hurricanes: large-scale environment and convective and precipitating areas from satellite microwave observations

    Directory of Open Access Journals (Sweden)

    C. Claud

    2010-10-01

    Full Text Available Subsynoptic scale vortices that have been likened to tropical cyclones or polar lows (medicanes are occasionally observed over the Mediterranean Sea. Generated over the sea, they are usually associated with strong winds and heavy precipitation and thus can be highly destructive in islands and costal areas. Only an accurate forecasting of such systems could mitigate these effects. However, at the moment, the predictability of these systems remains limited.

    Due to the scarcity of conventional observations, use is made of NOAA/MetOp satellite observations, for which advantage can be taken of the time coverage differences between the platforms that carry it, to give a very complete temporal description of the disturbances. A combination of AMSU-B (Advanced Microwave Sounding Unit-B/MHS (Microwave Humidity Sounder observations permit to investigate precipitation associated with these systems while coincident AMSU-A (Advanced Microwave Sounding Unit-A observations give insights into the larger synoptic-scale environment in which they occur.

    Three different cases (in terms of intensity, location, trajectory, duration, and periods of the year – May, September and December, respectively were investigated. Throughout these time periods, AMSU-A observations show that the persisting deep outflow of cold air over the sea together with an upper-level trough upstream constituted a favourable environment for the development of medicanes. AMSU-B/MHS based diagnostics show that convection and precipitation areas are large in the early stage of the low, but significantly reduced afterwards. Convection is maximum just after the upper-level trough, located upstream of cold mid-tropospheric air, reached its maximum intensity and acquired a cyclonic orientation.

  5. Sensitivity of Active and Passive Microwave Observations to Soil Moisture during Growing Corn

    Science.gov (United States)

    Judge, J.; Monsivais-Huertero, A.; Liu, P.; De Roo, R. D.; England, A. W.; Nagarajan, K.

    2011-12-01

    Soil moisture (SM) in the root zone is a key factor governing water and energy fluxes at the land surface and its accurate knowledge is critical to predictions of weather and near-term climate, nutrient cycles, crop-yield, and ecosystem productivity. Microwave observations, such as those at L-band, are highly sensitive to soil moisture in the upper few centimeters (near-surface). The two satellite-based missions dedicated to soil moisture estimation include, the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the planned NASA Soil Moisture Active/Passive (SMAP) [4] mission. The SMAP mission will include active and passive sensors at L-band to provide global observations of SM, with a repeat coverage of every 2-3 days. These observations can significantly improve root zone soil moisture estimates through data assimilation into land surface models (LSMs). Both the active (radar) and passive (radiometer) microwave sensors measure radiation quantities that are functions of soil dielectric constant and exhibit similar sensitivities to SM. In addition to the SM sensitivity, radar backscatter is highly sensitive to roughness of soil surface and scattering within the vegetation. These effects may produce a much larger dynamic range in backscatter than that produced due to SM changes alone. In this study, we discuss the field observations of active and passive signatures of growing corn at L-band from several seasons during the tenth Microwave, Water and Energy Balance Experiment (MicroWEX-10) conducted in North Central Florida, and to understand the sensitivity of these signatures to soil moisture under dynamic vegetation conditions. The MicroWEXs are a series of season-long field experiments conducted during the growing seasons of sweet corn, cotton, and energy cane over the past six years (for example, [22]). The corn was planted on July 5 and harvested on September 23, 2011 during MicroWEX-10. The size of the field was 0.04 km2 and the soils

  6. Dysonian Approach to SETI: A Fruitful Middle Ground?

    Science.gov (United States)

    Bradbury, R. J.; Cirkovic, M. M.; Dvorsky, G.

    We critically assess the prevailing currents in the Search for Extraterrestrial Intelligence (SETI), embodied in the notion of radio-searches for intentional artificial signals as envisioned by pioneers such as Frank Drake, Philip Morrison, Michael Papagiannis and others. In particular, we emphasize (1) the necessity of integrating SETI into a wider astrobiological and future studies context, (2) the relevance of and lessons to be learnt from the anti-SETI arguments, in particular Fermi's paradox, and (3) a need for complementary approach which we dub the Dysonian SETI. It is meaningfully derived from the inventive and visionary ideas of Freeman J. Dyson and his imaginative precursors, like Konstantin E. Tsiolkovsky, Olaf Stapledon, Nikola Tesla or John B. S. Haldane, who suggested macro-engineering projects as the focal points in the context of extrapolations about the future of humanity and, by analogy, other intelligent species. We consider practical ramifications of the Dysonian SETI and indicate some of the promising directions for future work.

  7. A mathematical model for evolution and SETI.

    Science.gov (United States)

    Maccone, Claudio

    2011-12-01

    Darwinian evolution theory may be regarded as a part of SETI theory in that the factor f(l) in the Drake equation represents the fraction of planets suitable for life on which life actually arose. In this paper we firstly provide a statistical generalization of the Drake equation where the factor f(l) is shown to follow the lognormal probability distribution. This lognormal distribution is a consequence of the Central Limit Theorem (CLT) of Statistics, stating that the product of a number of independent random variables whose probability densities are unknown and independent of each other approached the lognormal distribution when the number of factors increased to infinity. In addition we show that the exponential growth of the number of species typical of Darwinian Evolution may be regarded as the geometric locus of the peaks of a one-parameter family of lognormal distributions (b-lognormals) constrained between the time axis and the exponential growth curve. Finally, since each b-lognormal distribution in the family may in turn be regarded as the product of a large number (actually "an infinity") of independent lognormal probability distributions, the mathematical way is paved to further cast Darwinian Evolution into a mathematical theory in agreement with both its typical exponential growth in the number of living species and the Statistical Drake Equation.

  8. SETI The Search for Extraterrestrial Intelligence.

    Science.gov (United States)

    Jones, Barrie W.

    1991-01-01

    Discussed is the search for life on other planets similar to Earth based on the Drake equation. Described are search strategies and microwave searches. The reasons why people are searching are also discussed. (KR)

  9. The impact of land surface temperature on soil moisture anomaly detection from passive microwave observations

    Directory of Open Access Journals (Sweden)

    R. M. Parinussa

    2011-10-01

    Full Text Available For several years passive microwave observations have been used to retrieve soil moisture from the Earth's surface. Low frequency observations have the most sensitivity to soil moisture, therefore the current Soil Moisture and Ocean Salinity (SMOS and future Soil Moisture Active and Passive (SMAP satellite missions observe the Earth's surface in the L-band frequency. In the past, several satellite sensors such as the Advanced Microwave Scanning Radiometer-EOS (AMSR-E and WindSat have been used to retrieve surface soil moisture using multi-channel observations obtained at higher microwave frequencies. While AMSR-E and WindSat lack an L-band channel, they are able to leverage multi-channel microwave observations to estimate additional land surface parameters. In particular, the availability of Ka-band observations allows AMSR-E and WindSat to obtain coincident surface temperature estimates required for the retrieval of surface soil moisture. In contrast, SMOS and SMAP carry only a single frequency radiometer and therefore lack an instrument suited to estimate the physical temperature of the Earth. Instead, soil moisture algorithms from these new generation satellites rely on ancillary sources of surface temperature (e.g. re-analysis or near real time data from weather prediction centres. A consequence of relying on such ancillary data is the need for temporal and spatial interpolation, which may introduce uncertainties. Here, two newly-developed, large-scale soil moisture evaluation techniques, the triple collocation (TC approach and the Rvalue data assimilation approach, are applied to quantify the global-scale impact of replacing Ka-band based surface temperature retrievals with Modern Era Retrospective-analysis for Research and Applications (MERRA surface temperature output on the accuracy of WindSat and AMSR-E based surface soil moisture retrievals. Results demonstrate that under sparsely vegetated conditions, the use of

  10. The Advanced Microwave Scanning Radiometer-Earth Observing System Data Products from the Aqua Mission

    Science.gov (United States)

    Conway, D.; Troisi, V.; Marquis, M.; Armstrong, R.; Stroeve, J.; Maslanik, J.; Axford, Y.; Wolfe, J.

    2001-12-01

    The Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) is scheduled to launch on NASA's Aqua Satellite in early 2002. The Aqua mission is an important part of the NASA Earth Science Enterprise (ESE). The Aqua mission provides a multi-disciplinary study of the Earth's atmospheric, oceanic, cryospheric, and land processes and their relationship to global change. With six instruments aboard, the Aqua Satellite will travel in a polar, sun-synchronous orbit. The AMSR-E will measure passive microwave radiation, allowing for derivation of many geophysical parameters, including cloud properties, radiative energy flux, precipitation, land surface wetness, sea surface temperatures, sea ice, snow cover, and sea surface wind fields. The AMSR-E has much greater spatial resolution than previous passive microwave radiometers: approximately double the spatial resolution of the Scanning Multichannel Microwave Radiometer (SMMR) and the Special Sensor Microwave/Imager (SSM/I). Further, the AMSR-E combines in one sensor all the channels that SMMR and SSM/I had individually. The AMSR-E has the following frequencies (in GHz): 6.9, 10.7, 18.7, 23.8, 36.5, and 89. The level 1A data product will contain chronological antenna temperature count data. The level 2A data product will contain spatially-resampled brightness temperatures (in global swath format) at resolutions of 56, 38, 21, 12 and 5.4 km. Level 2B data will include ocean, soil moisture, and rain products. Level 3 data will include gridded ocean, soil moisture, and rain products; gridded snow water equivalent products; gridded brightness temperatures; and gridded sea ice concentration and snow depth products. The National Space Agency of Japan (NASDA) will process level 0 data to level 1A data. The AMSR-E Science Investigator-led Processing System (SIPS) will process the level 1A data product to level 2 and 3 data products. The National Snow and Ice Data Center (NSIDC) will archive and distribute all AMSR

  11. A Model for Estimation of Rain Rate on Tropical Land from TRMM Microwave Imager Radiometer Observations

    OpenAIRE

    C., PRABHAKARA; R., IACOVAZZI; J. M., YOO; K. M., KIM; NASA Goddard Space Flight Center; Center for Research on the Changing Earth System; EWHA Womans University; Science Systems and Applications, Inc.

    2005-01-01

    Over the tropical land regions scatter plots of the rain rate (R_), deduced from the TRMM Precipitation Radar (PR) versus the observed 85GHz brightness temperature (T_) made by the TRMM Microwave Imager (TMI) radiometer, for a period of a season over a given geographic region of 3°×5°(lat×lon), indicate that there are two maxima in rain rate. One strong maximum occurs when T_ has a value of about 220K, and the other weaker one when T_ is much colder ~150K. Also these two maxima are vividly re...

  12. Multi-Resolution L-Band Microwave Observations for Growing Vegetation during SMAPVEX16-IA

    Science.gov (United States)

    Judge, J.; Liu, P. W.; Chakrabarti, S.; De Roo, R. D.; Colliander, A.; Misra, S.; Yueh, S. H.; Williamson, R.; Ramos, I.; Tripp, S.; England, A. W.

    2016-12-01

    Microwave observations, such as those at L-band, are highly sensitive to soil moisture in the upper few centimeters (near-surface). The NASA Soil Moisture Active/Passive (SMAP) mission includes passive sensor at L-band that provides global observations of SM at 36 km, with a repeat coverage of every 2-3 days. These observations can significantly improve root zone soil moisture when data assimilated into land surface models (LSMs). The SMAP Validation Experiment-2016 (SMAPVEX16) was conducted during the summer from May through August 2016 in predominantly agricultural regions in Iowa (SMAPVEX16-IA) and Manitoba. During the experiment, aircraft and ground-based observations of L-band active and passive signatures of corn and soybean were obtained at the SMAP incidence angle of 40•. The aircraft measurements were obtained from the NASA/JPL Passive Active L- and S-band Sensor (PALS) during the time of SMAP overpasses from May 23 through June 3 and from August 3 through August 16, 2016. The ground-based University of Florida (UFLMR) and University of Michigan L-band Radiometer (UMLMR) systems observed microwave signatures of soybean and corn, respectively, at the Sweeney Farms, about 70 km north of Ames, IA. The ground-based sensors conducted every 15-minutes observations from May 23 through September 2, 2016. In addition, soil, vegetation, and micro-meteorological conditions were also monitored throughout the growing season. In this study, we discuss the satellite observations from SMAP and ESA Soil Moisture and Ocean Salinity (SMOS) along with those from PALS, and UFLMR/UMLMR at differing resolutions to understand implications of spatial heterogeneity on soil moisture retrievals in agricultural regions. resolutions. The preliminary results show SMAP observations at 36 km correspond well with the ground-based observations for corn, the predominant land cover in the region.

  13. Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles

    Science.gov (United States)

    Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo

    2009-01-01

    In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2

  14. Assessing Forest Cover Effects on Passive Microwave Snow Retrievals Using 2009 Snow Observations from NASA's Airborne Earth Science Microwave Imaging Radiometer (AESMIR)

    Science.gov (United States)

    Kim, E. J.

    2010-12-01

    Masking of the microwave signature of snow by forest cover remains one of the most significant impediments to global remote sensing of snow, if for no other reason than the large extent of forest areas. The current AMSR-E snow depth/water equivalent retrieval algorithm includes three elements to help address this masking: compensating terms that are functions of forest cover fraction and forest density, and the use of longer-wavelength 10 GHz observations offering less attenuation and scattering (compared to higher frequencies such as 18 GHz) by the canopy. Airborne observations were collected at both 10 and 18 GHz during flights of NASA’s AESMIR sensor. AESMIR is a passive microwave airborne imager covering microwave bands that are essential for observing key Earth System elements such as snow, sea ice, precipitation, soil moisture, ocean winds, sea surface temperature, vegetation, etc. AESMIR includes these bands in an efficient single mechanical package, and can perform conical and cross-track scans to simulate multiple satellite microwave imagers and sounders. As such, it is an Earth Science facility for post-launch calibration and validation of satellite sensors and as well as for pre-launch algorithm development & new microwave remote sensing discovery. It is well-suited as an inter-satellite calibration tool for constellation missions and long-term climate data records. New results from snow-related flights in January, 2009 will be presented. Imagery at 10 and 18 GHz will be presented from the flights over forested sites in the northeastern US, along with snow ground truth comparisons. The performance of the AMSR-E forest correction will be explored using these frequencies.

  15. Design of an L-Band Dual Feedhorn for the Purposes of Microwave Search for ExtraTerrensial Intelligence

    Directory of Open Access Journals (Sweden)

    M. Gimersky

    1994-07-01

    Full Text Available Logic behind the design of a dual feedhorn for the 26-meter Cassegrainian antennaof the Agassiz Station-Harvard-Smithsonian Observatory is presented in the paper. Theoretically predicted arid measured results in the "waterhole" band (1.4-1.7 GHz are presented. The antenna has been utilized in the Harvard Wide-Bandwidth HighResolution Microwave Search for ExtraTerrestrial Intelligence (SETI Program, with the Observatory as a SETI-dedicated facility.

  16. Evaluation of observed and pre-simulated passive microwave signatures over tropical oceans

    Science.gov (United States)

    Seo, Eun-Kyoung; Biggerstaff, Michael I.

    2011-11-01

    Bayesian algorithms are a common method of retrieving cloud properties from a set of observed passive microwave brightness temperature (TB) measurements. In practice, such methods often use predefined databases from cloud resolving models to perform the retrieval. Successful performance in these types of Bayesian retrievals is greatly affected by the similarity of TBs between observed and predefined databases. Here Empirical Orthogonal Function (EOF) analysis methods were used to illustrate the importance of predefined simulation databases on the ability to retrieve known regional variability in cloud structures across different parts of the tropical oceans and to provide insight on the relative impact of environmental conditions to limitations in cloud model microphysical parameterizations in retrieving different types of cloud structures. The spatial distributions of EOF coefficients in EOF space showed that there were both underrepresentation and overrepresentation between manifolds of the predefined and observed databases.

  17. Observation of microwave radiation using low-cost detectors at the ANKA storage ring*

    CERN Document Server

    Judin, V; Hofmann, A; Huttel, E; Kehrer, B; Klein, M; Marsching, S; Müller, A S; Nasse, M; Smale, N; Caspers, F; Peier, P

    2011-01-01

    Synchrotron light sources emit Coherent Synchrotron Radiation (CSR) for wavelengths longer than or equal to the bunch length. At most storage rings CSR cannot be observed, because the vacuum chamber cuts off radiation with long wavelengths. There are different approaches for shifting the CSR to shorter wavelengths that can propagate through the beam pipe, e.g.: the accelerator optics can be optimized for a low momentum compaction factor, thus reducing the bunch length. Alternatively, laser slicing can modulate substructures on long bunches [1]. Both techniques extend the CSR spectrum to shorter wavelengths, so that CSR is emitted at wavelengths below the waveguide shielding cut off. Usually fast detectors, like superconducting bolometer detector systems or Schottky barrier diodes, are used for observation of dynamic processes in accelerator physics. In this paper, we present observations of microwave radiation at ANKA using an alternative detector, a LNB (Low Noise Block) system. These devices are usually use...

  18. Saturn's rings: Particle composition and size distribution as constrained by microwave observations. I - Radar observations

    Science.gov (United States)

    Cuzzi, J. N.; Pollack, J. B.

    1978-01-01

    The radar backscattering characteristics of compositional and structural models of Saturn's rings are calculated and compared with observations of the absolute value, wavelength dependence, and degree of depolarization of the rings' radar cross section (reflectivity). The doubling method is used to calculate reflectivities for systems that are many particles thick using optical depths derived from observations at visible wavelengths. If the rings are many particles thick, irregular centimeter- to meter-sized particles composed primarily of water ice attain sufficiently high albedos and scattering efficiencies to explain the radar observations. In that case, the wavelength independence of radar reflectivity implies the existence of a broad particle size distribution; a narrower size distribution is also a possibility. Particles of primarily silicate composition are ruled out by the radar observations. Purely metallic particles may not be ruled out on the basis of existing radar observations. A monolayer of very large ice 'particles' that exhibit multiple internal scattering may not yet be ruled out.

  19. Evo-SETI Theory and Information Gap among Civilizations

    Science.gov (United States)

    Maccone, Claudio

    2016-05-01

    In a series of recent papers (Refs. [1] through [9]) this author gave the equations of his mathematical model of Evolution and SETI, simply called "Evo-SETI". Key features of Evo-SETI are: 1) The Statistical Drake Equation is the extension of the classical Drake equation into Statistics. Probability distributions of the number of ET civilizations in the Galaxy (lognormals) were given, and so is the probable distribution of the distance of ETs from us. 2) Darwinian Evolution is re-defined as a Geometric Brownian Motion (GBM) in the number of living species on Earth over the last 3.5 billion years. Its mean value grew exponentially in time and Mass Extinctions of the past are accounted for as unpredictable low GBM values. 3) The exponential growth of the number of species during Evolution is the geometric locus of the peaks of a one-parameter family of lognormal distributions (b-lognormals, starting each at a different time b=birth) constrained between the time axis and the exponential mean value. This accounts for cladistics (i.e. Evolution Lineages). The above key features of Evo-SETI Theory were already discussed by this author in Refs. [1] through [9]. Now about this paper's "novelties". 4) The lifespan of a living being, let it be a cell, an animal, a human, a historic human society, or even an ET society, is mathematically described as a finite b-lognormal. This author then described mathematically the historical development of eight human historic civilizations, from Ancient Greece to the USA, by virtue of b-lognormals. 5) Finally, the b-lognormal's entropy is the measure of a civilization's advancement level. By measuring the entropy difference between Aztecs and Spaniards in 1519, this author was able to account mathematically for the 20-million-Aztecs defeat by a few thousand Spaniards, due to the latter's technological (i.e. entropic) superiority. The same might unfortunately happen to Humans when they will face an ET superior civilization for the first

  20. Testing the Interacting Dark Energy Model with Cosmic Microwave Background Anisotropy and Observational Hubble Data

    Directory of Open Access Journals (Sweden)

    Weiqiang Yang

    2017-07-01

    Full Text Available The coupling between dark energy and dark matter provides a possible approach to mitigate the coincidence problem of the cosmological standard model. In this paper, we assumed the interacting term was related to the Hubble parameter, energy density of dark energy, and equation of state of dark energy. The interaction rate between dark energy and dark matter was a constant parameter, which was, Q = 3 H ξ ( 1 + w x ρ x . Based on the Markov chain Monte Carlo method, we made a global fitting on the interacting dark energy model from Planck 2015 cosmic microwave background anisotropy and observational Hubble data. We found that the observational data sets slightly favored a small interaction rate between dark energy and dark matter; however, there was not obvious evidence of interaction at the 1 σ level.

  1. Laboratory and observational studies of transient molecules at microwave and millimeter/submillimeter wavelengths

    Science.gov (United States)

    Zack, Lindsay Nicole

    In this dissertation, techniques of high-resolution rotational spectroscopy have been used to measure the spectra of molecules in both laboratory and astronomical settings. In the laboratory, small metal-bearing molecules containing zinc, iron, nickel, titanium, yttrium, and scandium have been studied at microwave and millimeter/submillimeter wavelengths in order to determine their rotational, fine, and hyperfine constants. These molecules were synthesized in situ in direct-absorption and Fourier-transform microwave spectrometers using Broida-type ovens and laser ablation methods. From the spectroscopic parameters, information about fundamental physical properties and electronic character could be obtained. Radio telescopes were used to measure the spectra of molecules in different interstellar environments. A new molecule, FeCN, was detected toward the circumstellar envelope of the carbon-rich asymtotic giant branch star, IRC+10216, marking the first iron-bearing molecule detected in the interstellar medium. The telescopes were also used to conduct a study of the evolved planetary nebula, NGC 7293, or the Helix Nebula. In the Helix, CO, HCO+, and H2CO were observed at several positions offset from the central star to obtain densities and kinetic temperatures throughout the Helix. A map of the HCO+ J = 1→ 0 transition was also constructed, showing that HCO+ is widespread throughout the Helix, instead of being photodissociated and destroyed, as theoretical models of planetary nebulae predict.

  2. CloudSat-Based Assessment of GPM Microwave Imager Snowfall Observation Capabilities

    Directory of Open Access Journals (Sweden)

    Giulia Panegrossi

    2017-12-01

    Full Text Available The sensitivity of Global Precipitation Measurement (GPM Microwave Imager (GMI high-frequency channels to snowfall at higher latitudes (around 60°N/S is investigated using coincident CloudSat observations. The 166 GHz channel is highlighted throughout the study due to its ice scattering sensitivity and polarization information. The analysis of three case studies evidences the important combined role of total precipitable water (TPW, supercooled cloud water, and background surface composition on the brightness temperature (TB behavior for different snow-producing clouds. A regression tree statistical analysis applied to the entire GMI-CloudSat snowfall dataset indicates which variables influence the 166 GHz polarization difference (166 ∆TB and its relation to snowfall. Critical thresholds of various parameters (sea ice concentration (SIC, TPW, ice water path (IWP are established for optimal snowfall detection capabilities. The 166 ∆TB can identify snowfall events over land and sea when critical thresholds are exceeded (TPW > 3.6 kg·m−2, IWP > 0.24 kg·m−2 over land, and SIC > 57%, TPW > 5.1 kg·m−2 over sea. The complex combined 166 ∆TB-TB relationship at higher latitudes and the impact of supercooled water vertical distribution are also investigated. The findings presented in this study can be exploited to improve passive microwave snowfall detection algorithms.

  3. Investigating the value of passive microwave observations for monitoring volcanic eruption source parameters

    Science.gov (United States)

    Montopoli, Mario; Cimini, Domenico; Marzano, Frank

    2016-04-01

    the dispersal fine-ash cloud, but tend to saturate near the source due to the strong optical extinction of ash cloud top layers. Conversely, observations at microwave (MW) channels from LEO satellites have demonstrated to carry additional information near the volcano source due to the relative lower opacity. This feature makes satellite MW complementary to IR radiometry for estimating source parameters close to the volcano emission, at the cost of coarser spatial resolution. The presentation shows the value of passive MW observations for the detection and quantitative retrieval of volcanic emission source parameters through the investigation of notable case studies, such as the eruptions of Grímsvötn (Iceland, May 2011) and Calbuco (Cile, April 2015), observed by the Special Sensor Microwave Imager/Sounder and the Advanced Technology Microwave Sounder.

  4. SETI as a part of Big History

    Science.gov (United States)

    Maccone, Claudio

    2014-08-01

    Big History is an emerging academic discipline which examines history scientifically from the Big Bang to the present. It uses a multidisciplinary approach based on combining numerous disciplines from science and the humanities, and explores human existence in the context of this bigger picture. It is taught at some universities. In a series of recent papers ([11] through [15] and [17] through [18]) and in a book [16], we developed a new mathematical model embracing Darwinian Evolution (RNA to Humans, see, in particular, [17] and Human History (Aztecs to USA, see [16]) and then we extrapolated even that into the future up to ten million years (see 18), the minimum time requested for a civilization to expand to the whole Milky Way (Fermi paradox). In this paper, we further extend that model in the past so as to let it start at the Big Bang (13.8 billion years ago) thus merging Big History, Evolution on Earth and SETI (the modern Search for ExtraTerrestrial Intelligence) into a single body of knowledge of a statistical type. Our idea is that the Geometric Brownian Motion (GBM), so far used as the key stochastic process of financial mathematics (Black-Sholes models and related 1997 Nobel Prize in Economics!) may be successfully applied to the whole of Big History. In particular, in this paper we derive Journal of Astrobiology and Acta Astronautica. But those mathematical results will not be repeated in this paper in order not to make it too long. Possibly a whole new book about GBMs will be written by the author. Mass Extinctions of the geological past also are one more topic that may be cast in the language of a decreasing GBM over a short time lapse, since Mass Extinctions are sudden all-lows in the number of living species. In this paper, we give formulae for the decreasing GBMs of Mass Extinctions, like the K-Pg one of 64 million years ago. Finally, we note that the Big History Equation is just the extension of the Drake Equation to 13.8 billion years of cosmic

  5. Observation of the exhaust plume from the space shuttle main engines using the microwave limb sounder

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2011-01-01

    Full Text Available A space shuttle launch deposits 700 tonnes of water in the atmosphere. Some of this water is released into the upper mesosphere and lower thermosphere where it may be directly detected by a limb sounding satellite instrument. We report measurements of water vapour plumes from shuttle launches made by the Microwave Limb Sounder (MLS on the Aura satellite. Approximately 50%–65% of shuttle launches are detected by MLS. The signal appears at a similar level across the upper 10 km of the MLS limb scan, suggesting that the bulk of the observed water is above the top of the scan. Only a small fraction at best of smaller launches (Ariane 5, Proton are detected. We conclude that the sensitivity of MLS is only just great enough to detect a shuttle sized launch, but that a suitably designed instrument of the same general type could detect the exhausts from a large proportion of heavy-lift launches.

  6. SYSTEMATIC EFFECTS IN POLARIZING FOURIER TRANSFORM SPECTROMETERS FOR COSMIC MICROWAVE BACKGROUND OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Nagler, Peter C.; Tucker, Gregory S. [Department of Physics, Brown University, Providence, RI 02912 (United States); Fixsen, Dale J.; Kogut, Alan, E-mail: peter.c.nagler@nasa.gov [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States)

    2015-11-15

    The detection of the primordial B-mode polarization signal of the cosmic microwave background (CMB) would provide evidence for inflation. Yet as has become increasingly clear, the detection of a such a faint signal requires an instrument with both wide frequency coverage to reject foregrounds and excellent control over instrumental systematic effects. Using a polarizing Fourier transform spectrometer (FTS) for CMB observations meets both of these requirements. In this work, we present an analysis of instrumental systematic effects in polarizing FTSs, using the Primordial Inflation Explorer (PIXIE) as a worked example. We analytically solve for the most important systematic effects inherent to the FTS—emissive optical components, misaligned optical components, sampling and phase errors, and spin synchronous effects—and demonstrate that residual systematic error terms after corrections will all be at the sub-nK level, well below the predicted 100 nK B-mode signal.

  7. Compressed sensing reconstruction of a string signal from interferometric observations of the cosmic microwave background

    Science.gov (United States)

    Wiaux, Y.; Puy, G.; Vandergheynst, P.

    2010-03-01

    We propose an algorithm for the reconstruction of the signal induced by cosmic strings in the cosmic microwave background (CMB), from radio-interferometric data at arcminute resolution. Radio interferometry provides incomplete and noisy Fourier measurements of the string signal, which exhibits sparse or compressible magnitude of the gradient due to the Kaiser-Stebbins effect. In this context, the versatile framework of compressed sensing naturally applies for solving the corresponding inverse problem. Our algorithm notably takes advantage of a model of the prior statistical distribution of the signal fitted on the basis of realistic simulations. Enhanced performance relative to the standard CLEAN algorithm is demonstrated by simulated observations under noise conditions including primary and secondary CMB anisotropies.

  8. Behavioral observations and operant procedures using microwaves as a heat source for young chicks

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, W.D.; McMillan, I.; Bate, L.A.; Otten, L.; Pei, D.C.

    1986-08-01

    Four trials, using operant conditioning procedures, were conducted to study the response of chicks, housed at 16 C, to microwave or infrared heat. Microwave power density was 26 mW/cm2 in Trial 1, 13 mW/cm2 in Trial 2, and 10 mW/cm2 in Trials 3 and 4. Chicks voluntarily demanded between 28 and 63% as much heat (min heat/hr) from microwave source as from infrared source at all power densities. There was no correlation, however, between the ratio of heat demanded and the power density used. There were no significant differences in growth between infrared- or microwave-heated chicks. It is evident from these studies that 8-day-old broiler chicks are capable of associating the performance of a task with a thermal reward provided by the microwaves. They are also able to utilize these microwaves through operant conditioning without any visible detrimental effect to their health or behavior.

  9. Toward all weather, long record, and real-time land surface temperature retrievals from microwave satellite observations

    Science.gov (United States)

    Jimenez, Carlos; Prigent, Catherine; Aires, Filipe; Ermida, Sofia

    2017-04-01

    The land surface temperature can be estimated from satellite passive microwave observations, with limited contamination from the clouds as compared to the infrared satellite retrievals. With ˜60% cloud cover in average over the globe, there is a need for "all weather," long record, and real-time estimates of land surface temperature (Ts) from microwaves. A simple yet accurate methodology is developed to derive the land surface temperature from microwave conical scanner observations, with the help of pre-calculated land surface microwave emissivities. The method is applied to the Special Sensor Microwave/Imagers (SSM/I) and the Earth observation satellite (EOS) Advanced Microwave Scanning Radiometer (AMSR-E) observations?, regardless of the cloud cover. The SSM/I results are compared to infrared estimates from International Satellite Cloud Climatology Project (ISCCP) and from Advanced Along Track Scanning Radiometer (AATSR), under clear-sky conditions. Limited biases are observed (˜0.5 K for both comparisons) with a root-mean-square difference (RMSD) of ˜5 K, to be compared to the RMSE of ˜3.5 K between ISCCP et AATSR. AMSR-E results are compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) clear-sky estimates. As both instruments are on board the same satellite, this reduces the uncertainty associated to the observations match-up, resulting in a lower RMSD of ˜ 4K. The microwave Ts is compared to in situ Ts time series from a collection of ground stations over a large range of environments. For 22 stations available in the 2003-2004 period, SSM/I Ts agrees very well for stations in vegetated environments (down to RMSD of ˜2.5 K for several stations), but the retrieval methodology encounters difficulties under cold conditions due to the large variability of snow and ice surface emissivities. For 10 stations in the year 2010, AMSR-E presents an all-station mean RMSD of ˜4.0 K with respect tom the ground Ts. Over the same stations, MODIS

  10. Snowmelt and Surface Freeze/Thaw Timings over Alaska derived from Passive Microwave Observations using a Wavelet Classifier

    Science.gov (United States)

    Steiner, N.; McDonald, K. C.; Dinardo, S. J.; Miller, C. E.

    2015-12-01

    Arctic permafrost soils contain a vast amount of organic carbon that will be released into the atmosphere as carbon dioxide or methane when thawed. Surface to air greenhouse gas fluxes are largely dependent on such surface controls as the frozen/thawed state of the snow and soil. Satellite remote sensing is an important means to create continuous mapping of surface properties. Advances in the ability to determine soil and snow freeze/thaw timings from microwave frequency observations improves upon our ability to predict the response of carbon gas emission to warming through synthesis with in-situ observation, such as the 2012-2015 Carbon in Arctic Reservoir Vulnerability Experiment (CARVE). Surface freeze/thaw or snowmelt timings are often derived using a constant or spatially/temporally variable threshold applied to time-series observations. Alternately, time-series singularity classifiers aim to detect discontinuous changes, or "edges", in time-series data similar to those that occur from the large contrast in dielectric constant during the freezing or thaw of soil or snow. We use multi-scale analysis of continuous wavelet transform spectral gradient brightness temperatures from various channel combinations of passive microwave radiometers, Advanced Microwave Scanning Radiometer (AMSR-E, AMSR2) and Special Sensor Microwave Imager (SSM/I F17) gridded at a 10 km posting with resolution proportional to the observational footprint. Channel combinations presented here aim to illustrate and differentiate timings of "edges" from transitions in surface water related to various landscape components (e.g. snow-melt, soil-thaw). To support an understanding of the physical basis of observed "edges" we compare satellite measurements with simple radiative transfer microwave-emission modeling of the snow, soil and vegetation using in-situ observations from the SNOw TELemetry (SNOTEL) automated weather stations. Results of freeze/thaw and snow-melt timings and trends are

  11. Iapetus' near surface thermal emission modeled and constrained using Cassini RADAR Radiometer microwave observations

    Science.gov (United States)

    Le Gall, A.; Leyrat, C.; Janssen, M. A.; Keihm, S.; Wye, L. C.; West, R.; Lorenz, R. D.; Tosi, F.

    2014-10-01

    Since its arrival at Saturn, the Cassini spacecraft has had only a few opportunities to observe Iapetus, Saturn's most distant regular satellite. These observations were all made from long ranges (>100,000 km) except on September 10, 2007, during Cassini orbit 49, when the spacecraft encountered the two-toned moon during its closest flyby so far. In this pass it collected spatially resolved data on the object's leading side, mainly over the equatorial dark terrains of Cassini Regio (CR). In this paper, we examine the radiometry data acquired by the Cassini RADAR during both this close-targeted flyby (referred to as IA49-3) and the distant Iapetus observations. In the RADAR's passive mode, the receiver functions as a radiometer to record the thermal emission from planetary surfaces at a wavelength of 2.2-cm. On the cold icy surfaces of Saturn's moons, the measured brightness temperatures depend both on the microwave emissivity and the physical temperature profile below the surface down to a depth that is likely to be tens of centimeters or even a few meters. Combined with the concurrent active data, passive measurements can shed light on the composition, structure and thermal properties of planetary regoliths and thus on the processes from which they have formed and evolved. The model we propose for Iapetus' microwave thermal emission is fitted to the IA49-3 observations and reveals that the thermal inertias sensed by the Cassini Radiometer over both CR and the bright mid-to-high latitude terrains, namely Ronceveaux Terra (RT) in the North and Saragossa Terra (ST) in the South, significantly exceed those measured by Cassini's CIRS (Composite Infrared Spectrometer), which is sensitive to much smaller depths, generally the first few millimeters of the surface. This implies that the subsurface of Iapetus sensed at 2.2-cm wavelength is more consolidated than the uppermost layers of the surface. In the case of CR, a thermal inertia of at least 50 J m-2 K-1 s-1/2, and

  12. Saturn's rings - Particle composition and size distribution as constrained by observations at microwave wavelengths. II - Radio interferometric observations

    Science.gov (United States)

    Cuzzi, J. N.; Pollack, J. B.; Summers, A. L.

    1980-01-01

    Theoretical models are presented of the brightness of Saturn's rings at microwave wavelengths (0.34-21.0 cm) including both intrinsic ring emission and diffuse scattering by the rings of the planetary emission. In addition, several previously existing sets of interferometric observations of the Saturn system at 0.83, 3.71, 6.0, 11.1, and 21.0 cm wavelengths are analyzed. A comparison of models and experimental data make it possible to establish improved constraints on the properties of the rings. In particular, it is found that (1) the maximum optical depths in the rings is 1.5 + or - 0.3 referred to visible wavelengths; (2) a significant decrease in ring optical depths from 3.7 to 21.0 cm makes it possible to rule out the possibility that more than 30% of the cross section of the rings is composed of particles larger than about a meter; and (3) the ring particles cannot be primarily of silicate composition (independently of particle size), and the particles cannot be primarily smaller than about 0.1 cm, independently of composition.

  13. SETI in the light of cosmic convergent evolution

    Science.gov (United States)

    Flores Martinez, Claudio L.

    2014-11-01

    Theodosius Dobzhansky, one of the founding fathers of the modern evolutionary synthesis, once famously stated that ;nothing makes sense in biology except in the light of evolution;. Here it will be argued that nothing in astrobiology makes sense except in the light of ;Cosmic Convergent Evolution; (CCE). This view of life contends that natural selection is a universal force of nature that leads to the emergence of similarly adapted life forms in analogous planetary biospheres. Although SETI historically preceded the rise of astrobiology that we have witnessed in the recent decade, one of its main tenets from the beginning was the convergence of life on a cosmic scale toward intelligent behavior and subsequent communication via technological means. The question of cultural convergence in terms of symbolic exchange, language and scientific capabilities between advanced interstellar civilizations has been the subject of ongoing debate. However, at the core of the search for extraterrestrial intelligence lies in essence a biological problem since even post-biological extraterrestrial intelligences must have had an origin based on self-replicating biopolymers. Thus, SETI assumes a propensity of the Universe towards biogenesis in accordance with CCE, a new evolutionary concept which posits the multiple emergence of life across the Cosmos. Consequently, we have to wonder about the biophilic properties the Universe apparently exhibits, as well as to try to find an encompassing theory that is able to explain this ;fine-tuning; in naturalistic terms. The aims of this paper are as follows: 1) to emphasize the importance of convergent evolution in astrobiology and ongoing SETI research; 2) to introduce novel and biology-centered cosmological ideas such as the ;Selfish Biocosm Hypothesis; and the ;Evo Devo Universe; as valuable arguments in theorizing about the origin and nature of extraterrestrial intelligence and 3) to synthesize these findings within an emerging post

  14. Back to the future: SETI before the space age

    Science.gov (United States)

    Dick, Steven J.

    1995-02-01

    In the late 1890s and early 1900s, before the advent of formalized search for extraterrestrial intelligence (SETI) programs, scientists such as Nikola Tesla and Gulielmo Marconi reported evidence of extraterrestrial radio signals. This paper reviews the history of 'interstellar/interplanetary radio communication'. The investigations of David P. Todd and Donald Menzel are discussed, and the fields of radio communication and radio astronomy are mentioned briefly.

  15. Five Years of SETI with the Allen Telescope Array: Lessons Learned

    Science.gov (United States)

    Harp, Gerald

    2016-01-01

    We discuss recent observations at the Allen Telescope Array (ATA) supporting a wide ranging Search for Extraterrestrial Intelligence (SETI). The ATA supports observations over the frequency range 1-10 GHz with three simultaneous phased array beams used in an anticoincidence detector for false positive rejection. Here we summarize observational results over the years 2011-2015 covering multiple campaigns of exoplanet stars, the galactic plane, infrared excess targets, etc. Approximately 2 x 108 signals were identified and classified over more than 5000 hours of observation. From these results we consider various approaches to the rapid identification of human generated interference in the process of the search for a signal with origins outside the radius of the Moon's orbit. We conclude that the multi-beam technique is superb tool for answering the very difficult question of the direction of origin of signals. Data-based simulations of future instruments with more than 3 beams are compared.

  16. The lure of local SETI: Fifty years of field experiments

    Science.gov (United States)

    Ailleris, Philippe

    2011-01-01

    With the commemoration in October 2007 of the Sputnik launch, space exploration celebrated its 50th anniversary. Despite impressive technological and scientific achievements the fascination for space has weakened during the last decades. One contributing factor has been the gradual disappearance of mankind's hope of discovering extraterrestrial life within its close neighbourhood. In striking contrast and since the middle of the 20th century, a non-negligible proportion of the population have already concluded that intelligent beings from other worlds do exist and visit Earth through space vehicles popularly called Unidentified Flying Objects (UFOs). In light of the continuous public interest for the UFO enigma symbolized by the recent widely diffused media announcements on the release of French and English governmental files; and considering the approach of broadening the strategies of the "Active SETI" approach and the existence of a rich multi-disciplinary UFO documentation of potential interest for SETI; this paper describes some past scientific attempts to demonstrate the physical reality of the phenomena and potentially the presence on Earth of probes of extraterrestrial origin. Details of the different instrumented field studies deployed by scientists and organizations during the period 1950-1990 in the USA, Canada and Europe are provided. In conclusion it will be argued that while continuing the current radio/optical SETI searches, there is the necessity to maintain sustaining attention to the topic of anomalous aerospace phenomena and to develop new rigorous research approaches.

  17. Observation of plasma microwave emission during the injection of supersonic plasma flows into magnetic arch

    Science.gov (United States)

    Viktorov, Mikhail; Mansfeld, Dmitry; Vodopyanov, Alexander; Golubev, Sergey

    2017-10-01

    Understanding of the energy transfer mechanisms from supersonic plasma flow into the thermal energy of plasma, waves and accelerated particles in the environment of planetary bow shocks and interplanetary shocks have been topical for many decades. Almost all mechanisms of energy dissipation in collisionless shock waves end with microscopic processes involving wave-particle interactions. Excitation of plasma waves in electron cyclotron frequency range plays an important role in the dissipation of bulk flow energy across the Earth bow shock. In the present work, the process of plasma deceleration during the injection of supersonic plasma flow across the magnetic field of an arched configuration is experimentally demonstrated. Pulsed plasma microwave emission in the electron cyclotron frequency range is observed. It is shown that the frequency spectrum of plasma emission is determined by the position of the deceleration region in the magnetic field of the magnetic arc and its bandwidth is defined by the magnetic field inhomogeneity in the deceleration region. The observed emission can be related to the cyclotron mechanism of wave generation by non-equilibrium energetic electrons in the dense plasma, especially excitation of electron Bernstein waves. The work was supported by RFBR (Project No. 16-32-60056).

  18. The Breakthrough Listen Search for Intelligent Life: the first SETI results and other future science.

    Science.gov (United States)

    Enriquez, J. Emilio; Breakthrough Listen Team

    2018-01-01

    The Breakthrough Listen (BL) Initiative is the largest campaign in human history on the search for extraterrestrial intelligence. The work presented here is the first BL search for engineered signals. This comprises a sample of 692 nearby stars within 50 pc. We used the Green Bank Telescope (GBT) to conduct observations over 1.1-1.9 GHz (L-band). Our observing strategy allows us to reject most of the detected signals as terrestrial interference. During the analysis, eleven stars show events that passed our thresholding algorithm, but detailed analysis of their properties indicates they are consistent with known examples of anthropogenic radio frequency interference. This small number of false positives and their understood properties give confidence on the techniques used for this search. We conclude that, at the time of our observations none of the observed systems host high-duty-cycle radio transmitters emitting at the observed frequencies with an EIRP of 10^13 W, readily achievable by our own civilization.We can place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. Our results suggest that fewer than ~0.1% of the stellar systems within 50 pc possess the type of transmitters searched in this survey. This work provides the most stringent limit on the number of low power radio transmitters around nearby stars to date. We explored several metics to compare our results to previous SETI efforts. We developed a new figure-of-merit that can encompass a wider set of parameters and can be used on future SETI experiments for a meaningful comparison.We note that the current BL state-of-the-art digital backend installed at the Green Bank Observatory is the fastest ever used for a SETI experiment by a factor of a few. Here we will describe the potential use of the BL backend by other groups on complementary science, as well as a mention the ongoing and potential collaborations focused in

  19. Evo-SETI: A Mathematical Tool for Cladistics, Evolution, and SETI

    Directory of Open Access Journals (Sweden)

    Claudio Maccone

    2017-04-01

    Full Text Available The discovery of new exoplanets makes us wonder where each new exoplanet stands along its way to develop life as we know it on Earth. Our Evo-SETI Theory is a mathematical way to face this problem. We describe cladistics and evolution by virtue of a few statistical equations based on lognormal probability density functions (pdf in the time. We call b-lognormal a lognormal pdf starting at instant b (birth. Then, the lifetime of any living being becomes a suitable b-lognormal in the time. Next, our “Peak-Locus Theorem” translates cladistics: each species created by evolution is a b-lognormal whose peak lies on the exponentially growing number of living species. This exponential is the mean value of a stochastic process called “Geometric Brownian Motion” (GBM. Past mass extinctions were all-lows of this GBM. In addition, the Shannon Entropy (with a reversed sign of each b-lognormal is the measure of how evolved that species is, and we call it EvoEntropy. The “molecular clock” is re-interpreted as the EvoEntropy straight line in the time whenever the mean value is exactly the GBM exponential. We were also able to extend the Peak-Locus Theorem to any mean value other than the exponential. For example, we derive in this paper for the first time the EvoEntropy corresponding to the Markov-Korotayev (2007 “cubic” evolution: a curve of logarithmic increase.

  20. Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results

    Science.gov (United States)

    Bennett, C. L.; Larson, D.; Weiland, J. L.; Jaorsik, N.; Hinshaw, G.; Odegard, N.; Smith, K. M.; Hill, R. S.; Gold, B.; Halpern, M; hide

    2013-01-01

    We present the final nine-year maps and basic results from the Wilkinson Microwave Anisotropy Probe (WMAP) mission. The full nine-year analysis of the time-ordered data provides updated characterizations and calibrations of the experiment. We also provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are examined to separate cosmic microwave background (CMB) anisotropy from foreground emission, and both types of signals are analyzed in detail.We provide new point source catalogs as well as new diffuse and point source foreground masks. An updated template-removal process is used for cosmological analysis; new foreground fits are performed, and new foreground reduced are presented.We nowimplement an optimal C(exp -1)1 weighting to compute the temperature angular power spectrum. The WMAP mission has resulted in a highly constrained Lambda-CDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements. When WMAP data are combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant measurements, we find that big bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (N(sub eff) = 3.84 +/- 0.40). The model fit also implies that the age of the universe is (sub 0) = 13.772 +/- 0.059 Gyr, and the fit Hubble constant is H(sub 0) = 69.32 +/- 0.80 km/s/ Mpc. Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity, reported earlier by the WMAP team, now has high statistical significance (n(sub s) = 0.9608+/-0.0080); and the universe is close to flat/Euclidean (Omega = -0.0027+0.0039/-0.0038). Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68,000 for the standard six

  1. NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: FINAL MAPS AND RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C. L.; Larson, D.; Weiland, J. L. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States); Jarosik, N.; Page, L. [Department of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544-0708 (United States); Hinshaw, G.; Halpern, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Odegard, N.; Hill, R. S. [ADNET Systems, Inc., 7515 Mission Drive, Suite A100, Lanham, MD 20706 (United States); Smith, K. M. [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Gold, B. [School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States); Komatsu, E. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, D-85741 Garching (Germany); Nolta, M. R. [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada); Spergel, D. N. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544-1001 (United States); Wollack, E.; Kogut, A. [Code 665, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Dunkley, J. [Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Limon, M. [Columbia Astrophysics Laboratory, 550 West 120th Street, Mail Code 5247, New York, NY 10027-6902 (United States); Meyer, S. S. [Departments of Astrophysics and Physics, KICP and EFI, University of Chicago, Chicago, IL 60637 (United States); Tucker, G. S., E-mail: cbennett@jhu.edu [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912-1843 (United States); and others

    2013-10-01

    We present the final nine-year maps and basic results from the Wilkinson Microwave Anisotropy Probe (WMAP) mission. The full nine-year analysis of the time-ordered data provides updated characterizations and calibrations of the experiment. We also provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are examined to separate cosmic microwave background (CMB) anisotropy from foreground emission, and both types of signals are analyzed in detail. We provide new point source catalogs as well as new diffuse and point source foreground masks. An updated template-removal process is used for cosmological analysis; new foreground fits are performed, and new foreground-reduced CMB maps are presented. We now implement an optimal C {sup –1} weighting to compute the temperature angular power spectrum. The WMAP mission has resulted in a highly constrained ΛCDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements. When WMAP data are combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant measurements, we find that big bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (N {sub eff} = 3.84 ± 0.40). The model fit also implies that the age of the universe is t {sub 0} = 13.772 ± 0.059 Gyr, and the fit Hubble constant is H {sub 0} = 69.32 ± 0.80 km s{sup –1} Mpc{sup –1}. Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity, reported earlier by the WMAP team, now has high statistical significance (n{sub s} = 0.9608 ± 0.0080); and the universe is close to flat/Euclidean (Ω{sub k} = -0.0027{sup +0.0039}{sub -0.0038}). Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor

  2. Observations of the Polarisation of the Anomalous Microwave Emission: A Review

    Directory of Open Access Journals (Sweden)

    J. A. Rubiño-Martín

    2012-01-01

    Full Text Available The observational status of the polarisation of the anomalous microwave emission (AME is reviewed, both for individual compact Galactic regions as well as for the large-scale Galactic emission. There are six Galactic regions with existing polarisation constraints in the relevant range of 10–40 GHz: four dust clouds (Perseus, ρ Ophiuchi, LDN1622, and Pleiades and two HII regions (LPH96 and the Helix nebula. These constraints are discussed in detail and are complemented by deriving upper limits on the polarisation of the AME for those objects without published WMAP constraints. For the case of large-scale emission, two recent works, based on WMAP data, are reviewed. Currently, the best constraints on the fractional polarisation of the AME, at frequencies near the peak of the emission (i.e., 20–30 GHz, are at the level of ~1% (95.4% confidence level. Finally, we compare these constraints with the predictions of some theoretical AME models and discuss the possible impact of polarised AME on future primordial B-mode experiments.

  3. Microwave to Submillimeter Observations of Molecules in the Laboratory and in Space

    Science.gov (United States)

    Halfen, DeWayne

    2013-06-01

    The primary method of identifying molecular species in interstellar space is radio astronomy. Observations performed at radio telescopes are based on high-resolution laboratory measurements of the pure rotational spectrum of a molecule. With this technique, over 150 different chemical compounds have been securely detected in interstellar gas. High-resolution rotational spectra have accuracies of one part in 107 - 108, and provide the characteristic frequencies that are used to search for these species. Rotational spectra are typically recorded using direct absorption methods, Fourier transform microwave/millimeter-wave spectroscopy, and velocity modulation techniques. Also exotic synthesis methods, such as DC and AC glow discharges, pulsed supersonic jet expansions, laser ablation, and Broida-type ovens, are often required to produce these molecules. Recent laboratory and astronomical studies have expanded set of molecules that are now known in interstellar/circumstellar gas. The first negative molecular ions have been detected in cold, dark clouds and circumstellar envelopes. The iron-bearing species FeCN was also recently measured in the laboratory and discovered in the gas surrounding a carbon-rich AGB star, the first iron-containing species found in space. New observations of oxygen-rich stars have shown that metal-bearing oxides and hydroxides are also abundant circumstellar species in these environments. These new discoveries, as well as recent laboratory results for other potential interstellar species, will also be presented, in particular those for ScO, ScC2, and AlC2. In addition, the need for more measurements of metal-containing molecules will be discussed.

  4. A Model for Estimation of Rain Rate on Tropical Land from TRMM Microwave Imager Radiometer Observations

    Science.gov (United States)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Kim, Kyu-Myong

    2004-01-01

    Over the tropical land regions observations of the 85 GHz brightness temperature (T(sub 85v)) made by the TRMM Microwave Imager (TMI) radiometer when analyzed with the help of rain rate (R(sub pR)) deduced from the TRMM Precipitation Radar (PR) indicate that there are two maxima in rain rate. One strong maximum occurs when T(sub 85) has a value of about 220 K and the other weaker one when T(sub 85v) is much colder approx. 150 K. Together with the help of earlier studies based on airborne Doppler Radar observations and radiative transfer theoretical simulations, we infer the maximum near 220 K is a result of relatively weak scattering due to super cooled rain drops and water coated ice hydrometeors associated with a developing thunderstorm (Cb) that has a strong updraft. The other maximum is associated with strong scattering due to ice particles that are formed when the updraft collapses and the rain from the Cb is transit2oning from convective type to stratiform type. Incorporating these ideas and with a view to improve the estimation of rain rate from existing operational method applicable to the tropical land areas, we have developed a rain retrieval model. This model utilizes two parameters, that have a horizontal scale of approx. 20km, deduced from the TMI measurements at 19, 21 and 37 GHz (T(sub 19v), T(sub 21v), T(sub 37v). The third parameter in the model, namely the horizontal gradient of brightness temperature within the 20 km scale, is deduced from TMI measurements at 85 GHz. Utilizing these parameters our retrieval model is formulated to yield instantaneous rain rate on a scale of 20 km and seasonal average on a mesoscale that agree well with that of the PR.

  5. Extraterrestrial intelligence and human imagination SETI at the intersection of science, religion, and culture

    CERN Document Server

    Traphagan, John

    2015-01-01

    The search for extraterrestrial intelligence (SETI) represents one of the most significant crossroads at which the assumptions and methods of scientific inquiry come into direct contact with—and in many cases conflict with—those of religion. Indeed, at the core of SETI is the same question that motivates many interested in religion: What is the place of humanity in the universe? Both scientists involved with SETI (and in other areas) and those interested in and dedicated to some religious traditions are engaged in contemplating these types of questions, even if their respective approaches and answers differ significantly. This book explores this intersection with a focus on three core points: 1) the relationship between science and religion as it is expressed within the framework of SETI research, 2) the underlying assumptions, many of which are tacitly based upon cultural values common in American society, that have shaped the ways in which SETI researchers have conceptualized the nature of their endeavo...

  6. Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results

    Science.gov (United States)

    Weiland, J.L.; Hill, R.S.; Odegard, 3.; Larson, D.; Bennett, C.L.; Dunkley, J.; Jarosik, N.; Page, L.; Spergel, D.N.; Halpern, M.; hide

    2008-01-01

    The Wilkinson Microwave Anisotropy Probe (WMAP) is a Medium-Class Explorer (MIDEX) satellite aimed at elucidating cosmology through full-sky observations of the cosmic microwave background (CMB). The WMAP full-sky maps of the temperature and polarization anisotropy in five frequency bands provide our most accurate view to date of conditions in the early universe. The multi-frequency data facilitate the separation of the CMB signal from foreground emission arising both from our Galaxy and from extragalactic sources. The CMB angular power spectrum derived from these maps exhibits a highly coherent acoustic peak structure which makes it possible to extract a wealth of information about the composition and history of the universe. as well as the processes that seeded the fluctuations. WMAP data have played a key role in establishing ACDM as the new standard model of cosmology (Bennett et al. 2003: Spergel et al. 2003; Hinshaw et al. 2007: Spergel et al. 2007): a flat universe dominated by dark energy, supplemented by dark matter and atoms with density fluctuations seeded by a Gaussian, adiabatic, nearly scale invariant process. The basic properties of this universe are determined by five numbers: the density of matter, the density of atoms. the age of the universe (or equivalently, the Hubble constant today), the amplitude of the initial fluctuations, and their scale dependence. By accurately measuring the first few peaks in the angular power spectrum, WMAP data have enabled the following accomplishments: Showing the dark matter must be non-baryonic and interact only weakly with atoms and radiation. The WMAP measurement of the dark matter density puts important constraints on supersymmetric dark matter models and on the properties of other dark matter candidates. With five years of data and a better determination of our beam response, this measurement has been significantly improved. Precise determination of the density of atoms in the universe. The agreement between

  7. Visual observation and quantitative measurement of the microwave absorbing effect at X band.

    Science.gov (United States)

    Zhao, L; Chen, X; Ong, C K

    2008-12-01

    We have set up a two-dimensional spatial field mapping system to measure graphically the quasi-free-space electromagnetic wave in a parallel plate waveguide. Our apparatus illustrates a potential application in characterizing the microwave absorbing materials. From the measured mappings of the microwave field, the visualization of spatial physical process and quantitative characterization of reflectivity coefficients can be achieved. This simple apparatus has a remarkable advantage over with conventional testing methods which usually involve huge, expensive anechoic chambers and demand samples of large size.

  8. SECOND SEASON QUIET OBSERVATIONS: MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION POWER SPECTRUM AT 95 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, D.; Dumoulin, R. N.; Newburgh, L. B.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K.; Reeves, R. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Monsalve, R.; Bustos, R. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Naess, S. K.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Bronfman, L. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Church, S. E. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Varian Physics Building, 382 Via Pueblo Mall, Stanford, CA 94305 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gaier, T., E-mail: ibuder@uchicago.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Collaboration: QUIET Collaboration; and others

    2012-12-01

    The Q/U Imaging ExperimenT (QUIET) has observed the cosmic microwave background (CMB) at 43 and 95 GHz. The 43 GHz results have been published in a previous paper, and here we report the measurement of CMB polarization power spectra using the 95 GHz data. This data set comprises 5337 hr of observations recorded by an array of 84 polarized coherent receivers with a total array sensitivity of 87 {mu}K{radical}s. Four low-foreground fields were observed, covering a total of {approx}1000 deg{sup 2} with an effective angular resolution of 12.'8, allowing for constraints on primordial gravitational waves and high signal-to-noise measurements of the E-modes across three acoustic peaks. The data reduction was performed using two independent analysis pipelines, one based on a pseudo-C {sub l} (PCL) cross-correlation approach, and the other on a maximum-likelihood (ML) approach. All data selection criteria and filters were modified until a predefined set of null tests had been satisfied before inspecting any non-null power spectrum. The results derived by the two pipelines are in good agreement. We characterize the EE, EB, and BB power spectra between l = 25 and 975 and find that the EE spectrum is consistent with {Lambda}CDM, while the BB power spectrum is consistent with zero. Based on these measurements, we constrain the tensor-to-scalar ratio to r = 1.1{sup +0.9} {sub -0.8} (r < 2.8 at 95% C.L.) as derived by the ML pipeline, and r = 1.2{sup +0.9} {sub -0.8} (r < 2.7 at 95% C.L.) as derived by the PCL pipeline. In one of the fields, we find a correlation with the dust component of the Planck Sky Model, though the corresponding excess power is small compared to statistical errors. Finally, we derive limits on all known systematic errors, and demonstrate that these correspond to a tensor-to-scalar ratio smaller than r = 0.01, the lowest level yet reported in the literature.

  9. Four decades of microwave satellite soil moisture observations: Part 1. A review of retrieval algorithms

    Science.gov (United States)

    Karthikeyan, L.; Pan, Ming; Wanders, Niko; Kumar, D. Nagesh; Wood, Eric F.

    2017-11-01

    The satellite based passive (radiometer) and active (radar) microwave sensors enhanced our ability to retrieve soil moisture at global scales. It has been almost four decades since the first passive microwave satellite sensor was launched in 1978. Since then soil moisture has gained considerable attention in hydro-meteorological, climate, and agricultural research resulting in the deployment of two dedicated missions in the last decade, SMOS and SMAP. Microwave retrievals require an algorithm to estimate soil moisture from satellite measurements. In this Part 1 of a two-part review series, we provide a synthesis of four decades of research and development on the passive and active microwave soil moisture retrieval algorithms. The algorithms associated with passive sensors use the radiometer brightness temperatures, while active sensors use the radar backscatter measurements to retrieve soil moisture. The physics of both algorithm classes are based on the fact that the microwave measurements at lower frequencies are influenced by the soil dielectric property, which acts as a proxy for the surface soil moisture content. In this review effort, the emphasis is laid on the physical models of the passive and the active retrieval algorithms. These algorithms facilitate to obtain the individual radiative contributions from soil, vegetation, and atmosphere that reach satellite sensors after mixing (roughness), scattering, and attenuation. In the process, we looked into the current research efforts to improve individual aspects of the algorithms, followed by a description of different retrieval procedures. In Part 2 of this review series, performance evaluation and inter-sensor comparisons of soil moisture of eight passive and two active sensors are carried out using 1058 stations along with model soil moisture data in the Contiguous United States (CONUS) region.

  10. Observations of frozen skin of southern ocean from multifrequency scanning microwave radiometer (MSMR) onboard oceansat - 1

    Science.gov (United States)

    Vyas, N.; Bhandari, S.; Dash, M.; Pandey, P.; Khare, N.

    Encircling the Antarctic, Southern Ocean connects all the three oceans of the world with fastest current system found anywhere in the world. The region is thermally very stable and is covered with ice, which has a strong seasonal variability. The sea ice pulsates annually with seasonal migration varying from 4 million square kilometer to 20 million square kilometer during summer and winter respectively. This has strong influence on energy balance of the ocean-ice-atmosphere system, and hence on atmospheric general circulation affecting weather and climate. Sea ice also works as an insulator thus inhibiting the energy flux between ocean and atmosphere. It also influences the ecosystem of the southern ocean, which has rich fish resources with global economic values such as krill and tooth fish. During winter Krill survives on algae found at the under side of the sea ice. The southern ocean is known to have high nutrition but low concentration of chlorophyll-a, which is a proxy of the phytoplankton. It is now understood that iron is the limiting factor as has been shown by various iron fertilization experiments. Passive microwave radiometry from space has been extensively used for the study of sea ice types and concentration in the Arctic and the Antarctic regions. Since late 1970s, data from SMMR and SSM/I have been used to study trends in sea ice extent and area. We have further extended the above studies by using data from OCEANSAT - 1 MSMR. The data, acquired at 18 GHz (H) with 50 kilometer resolution and having a swath of 1360 kilometer and a repeat cycle of 2 days, was processed to generate the brightness temperature maps over the Antarctica for a period of 2 years and the results were analyzed in conjunction with those obtained earlier (since 1978) through the study of SMMR and SSM/I data. Besides strong seasonal variability, our analysis shows an increasing trend in the sea ice extent during the recent years and the rate appears to be accelerating contrary to

  11. 3D Online Submicron Scale Observation of Mixed Metal Powder's Microstructure Evolution in High Temperature and Microwave Compound Fields

    Directory of Open Access Journals (Sweden)

    Dan Kang

    2014-01-01

    Full Text Available In order to study the influence on the mechanical properties caused by microstructure evolution of metal powder in extreme environment, 3D real-time observation of the microstructure evolution of Al-Ti mixed powder in high temperature and microwave compound fields was realized by using synchrotron radiation computerized topography (SR-CT technique; the spatial resolution was enhanced to 0.37 μm/pixel through the designed equipment and the introduction of excellent reconstruction method for the first time. The process of microstructure evolution during sintering was clearly distinguished from 2D and 3D reconstructed images. Typical sintering parameters such as sintering neck size, porosity, and particle size of the sample were presented for quantitative analysis of the influence on the mechanical properties and the sintering kinetics during microwave sintering. The neck size-time curve was obtained and the neck growth exponent was 7.3, which indicated that surface diffusion was the main diffusion mechanism; the reason was the eddy current loss induced by the external microwave fields providing an additional driving force for mass diffusion on the particle surface. From the reconstructed images and the curve of porosity and average particle size versus temperature, it was believed that the presence of liquid phase aluminum accelerated the densification and particle growth.

  12. 3D online submicron scale observation of mixed metal powder's microstructure evolution in high temperature and microwave compound fields.

    Science.gov (United States)

    Kang, Dan; Xu, Feng; Hu, Xiao-fang; Dong, Bo; Xiao, Yu; Xiao, Ti-qiao

    2014-01-01

    In order to study the influence on the mechanical properties caused by microstructure evolution of metal powder in extreme environment, 3D real-time observation of the microstructure evolution of Al-Ti mixed powder in high temperature and microwave compound fields was realized by using synchrotron radiation computerized topography (SR-CT) technique; the spatial resolution was enhanced to 0.37  μm/pixel through the designed equipment and the introduction of excellent reconstruction method for the first time. The process of microstructure evolution during sintering was clearly distinguished from 2D and 3D reconstructed images. Typical sintering parameters such as sintering neck size, porosity, and particle size of the sample were presented for quantitative analysis of the influence on the mechanical properties and the sintering kinetics during microwave sintering. The neck size-time curve was obtained and the neck growth exponent was 7.3, which indicated that surface diffusion was the main diffusion mechanism; the reason was the eddy current loss induced by the external microwave fields providing an additional driving force for mass diffusion on the particle surface. From the reconstructed images and the curve of porosity and average particle size versus temperature, it was believed that the presence of liquid phase aluminum accelerated the densification and particle growth.

  13. Nonlinear bias analysis and correction of microwave temperature sounder observations for FY-3C meteorological satellite

    Science.gov (United States)

    Hu, Taiyang; Lv, Rongchuan; Jin, Xu; Li, Hao; Chen, Wenxin

    2018-01-01

    The nonlinear bias analysis and correction of receiving channels in Chinese FY-3C meteorological satellite Microwave Temperature Sounder (MWTS) is a key technology of data assimilation for satellite radiance data. The thermal-vacuum chamber calibration data acquired from the MWTS can be analyzed to evaluate the instrument performance, including radiometric temperature sensitivity, channel nonlinearity and calibration accuracy. Especially, the nonlinearity parameters due to imperfect square-law detectors will be calculated from calibration data and further used to correct the nonlinear bias contributions of microwave receiving channels. Based upon the operational principles and thermalvacuum chamber calibration procedures of MWTS, this paper mainly focuses on the nonlinear bias analysis and correction methods for improving the calibration accuracy of the important instrument onboard FY-3C meteorological satellite, from the perspective of theoretical and experimental studies. Furthermore, a series of original results are presented to demonstrate the feasibility and significance of the methods.

  14. New Evo-SETI results about civilizations and molecular clock

    Science.gov (United States)

    Maccone, Claudio

    2017-01-01

    In two recent papers (Maccone 2013, 2014) as well as in the book (Maccone 2012), this author described the Evolution of life on Earth over the last 3.5 billion years as a lognormal stochastic process in the increasing number of living Species. In (Maccone 2012, 2013), the process used was `Geometric Brownian Motion' (GBM), largely used in Financial Mathematics (Black-Sholes models). The GBM mean value, also called `the trend', always is an exponential in time and this fact corresponds to the so-called `Malthusian growth' typical of population genetics. In (Maccone 2014), the author made an important generalization of his theory by extending it to lognormal stochastic processes having an arbitrary trend m L (t), rather than just a simple exponential trend as the GBM have. The author named `Evo-SETI' (Evolution and SETI) his theory inasmuch as it may be used not only to describe the full evolution of life on Earth from RNA to modern human societies, but also the possible evolution of life on exoplanets, thus leading to SETI, the current Search for ExtraTerrestrial Intelligence. In the Evo-SETI Theory, the life of a living being (let it be a cell or an animal or a human or a Civilization of humans or even an ET Civilization) is represented by a b-lognormal, i.e. a lognormal probability density function starting at a precise instant b (`birth') then increasing up to a peak-time p, then decreasing to a senility-time s (the descending inflexion point) and then continuing as a straight line down to the death-time d (`finite b-lognormal'). (1) Having so said, the present paper describes the further mathematical advances made by this author in 2014-2015, and is divided in two halves: Part One, devoted to new mathematical results about the History of Civilizations as b-lognormals, and (2) Part Two, about the applications of the Evo-SETI Theory to the Molecular Clock, well known to evolutionary geneticists since 50 years: the idea is that our EvoEntropy grows linearly in time

  15. Four decades of microwave satellite soil moisture observations: Part 2. Product validation and inter-satellite comparisons

    Science.gov (United States)

    Karthikeyan, L.; Pan, Ming; Wanders, Niko; Kumar, D. Nagesh; Wood, Eric F.

    2017-11-01

    Soil moisture is widely recognized as an important land surface variable that provides a deeper knowledge of land-atmosphere interactions and climate change. Space-borne passive and active microwave sensors have become valuable and essential sources of soil moisture observations at global scales. Over the past four decades, several active and passive microwave sensors have been deployed, along with the recent launch of two fully dedicated missions (SMOS and SMAP). Signifying the four decades of microwave remote sensing of soil moisture, this Part 2 of the two-part review series aims to present an overview of how our knowledge in this field has improved in terms of the design of sensors and their accuracy for retrieving soil moisture. The first part discusses the developments made in active and passive microwave soil moisture retrieval algorithms. We assess the evolution of the products of various sensors over the last four decades, in terms of daily coverage, temporal performance, and spatial performance, by comparing the products of eight passive sensors (SMMR, SSM/I, TMI, AMSR-E, WindSAT, AMSR2, SMOS and SMAP), two active sensors (ERS-Scatterometer, MetOp-ASCAT), and one active/passive merged soil moisture product (ESA-CCI combined product) with the International Soil Moisture Network (ISMN) in-situ stations and the Variable Infiltration Capacity (VIC) land surface model simulations over the Contiguous United States (CONUS). In the process, the regional impacts of vegetation conditions on the spatial and temporal performance of soil moisture products are investigated. We also carried out inter-satellite comparisons to study the roles of sensor design and algorithms on the retrieval accuracy. We find that substantial improvements have been made over recent years in this field in terms of daily coverage, retrieval accuracy, and temporal dynamics. We conclude that the microwave soil moisture products have significantly evolved in the last four decades and will

  16. Intercomparison of O3 profiles observed by SCIAMACHY and ground based microwave instruments

    Directory of Open Access Journals (Sweden)

    M. Palm

    2005-01-01

    Full Text Available Ozone profiles retrieved from limb scattering measurements of the SCIAMACHY instrument based on the satellite ENVISAT are compared to ground-based low altitude resolution remote sensors. All profiles are retrieved using optimal estimation. Following the work of Rodgers and Connor (2003 the retrievals of the ground-based instruments are simulated using the SCIAMACHY retrieval. The SCIAMACHY results and the results of the ground-based microwave radiometer in Bremen and Ny Ålesund agree within the expected covariance of the intercomparison.

  17. SETI meets a social intelligence: Dolphins as a model for real-time interaction and communication with a sentient species

    Science.gov (United States)

    Herzing, Denise L.

    2010-12-01

    In the past SETI has focused on the reception and deciphering of radio signals from potential remote civilizations. It is conceivable that real-time contact and interaction with a social intelligence may occur in the future. A serious look at the development of relationship, and deciphering of communication signals within and between a non-terrestrial, non-primate sentient species is relevant. Since 1985 a resident community of free-ranging Atlantic spotted dolphins has been observed regularly in the Bahamas. Life history, relationships, regular interspecific interactions with bottlenose dolphins, and multi-modal underwater communication signals have been documented. Dolphins display social communication signals modified for water, their body types, and sensory systems. Like anthropologists, human researchers engage in benign observation in the water and interact with these dolphins to develop rapport and trust. Many individual dolphins have been known for over 20 years. Learning the culturally appropriate etiquette has been important in the relationship with this alien society. To engage humans in interaction the dolphins often initiate spontaneous displays, mimicry, imitation, and synchrony. These elements may be emergent/universal features of one intelligent species contacting another for the intention of initiating interaction. This should be a consideration for real-time contact and interaction for future SETI work.

  18. Soil moisture-runoff relation at the catchment scale as observed with coarse resolution microwave remote sensing

    Directory of Open Access Journals (Sweden)

    K. Scipal

    2005-01-01

    Full Text Available Microwave remote sensing offers emerging capabilities to monitor global hydrological processes. Instruments like the two dedicated soil moisture missions SMOS and HYDROS or the Advanced Scatterometer onboard METOP will provide a flow of coarse resolution microwave data, suited for macro-scale applications. Only recently, the scatterometer onboard of the European Remote Sensing Satellite, which is the precursor instrument of the Advanced Scatterometer, has been used successfully to derive soil moisture information at global scale with a spatial resolution of 50 km. Concepts of how to integrate macro-scale soil moisture data in hydrologic models are however still vague. In fact, the coarse resolution of the data provided by microwave radiometers and scatterometers is often considered to impede hydrological applications. Nevertheless, even if most hydrologic models are run at much finer scales, radiometers and scatterometers allow monitoring of atmosphere-induced changes in regional soil moisture patterns. This may prove to be valuable information for modelling hydrological processes in large river basins (>10 000 km2. In this paper, ERS scatterometer derived soil moisture products are compared to measured runoff of the Zambezi River in south-eastern Africa for several years (1992–2000. This comparison serves as one of the first demonstrations that there is hydrologic relevant information in coarse resolution satellite data. The observed high correlations between basin-averaged soil moisture and runoff time series (R2>0.85 demonstrate that the seasonal change from low runoff during the dry season to high runoff during the wet season is well captured by the ERS scatterometer. It can be expected that the high correlations are to a certain degree predetermined by the pronounced inter-annual cycle observed in the discharge behaviour of the Zambezi. To quantify this effect, time series of anomalies have been compared. This analysis showed that

  19. Hoar crystal development and disappearance at Dome C, Antarctica: observation by near-infrared photography and passive microwave satellite

    Directory of Open Access Journals (Sweden)

    N. Champollion

    2013-08-01

    Full Text Available Hoar crystals episodically cover the snow surface in Antarctica and affect the roughness and reflective properties of the air–snow interface. However, little is known about their evolution and the processes responsible for their development and disappearance despite a probable influence on the surface mass balance and energy budget. To investigate hoar evolution, we use continuous observations of the surface by in situ near-infrared photography and by passive microwave remote sensing at Dome C in Antarctica. From the photography data, we retrieved a daily indicator of the presence/absence of hoar crystals using a texture analysis algorithm. The analysis of this 2 yr long time series shows that Dome C surface is covered almost half of the time by hoar. The development of hoar crystals takes a few days and seems to occur whatever the meteorological conditions. In contrast, the disappearance of hoar is rapid (a few hours and coincident with either strong winds or with moderate winds associated with a change in wind direction from southwest (the prevailing direction to southeast. From the microwave satellite data, we computed the polarisation ratio (i.e. horizontal over vertical polarised brightness temperatures, an indicator known to be sensitive to hoar in Greenland. Photography data and microwave polarisation ratio are correlated, i.e. high values of polarisation ratio which theoretically correspond to low snow density values near the surface are associated with the presence of hoar crystals in the photography data. Satellite data over nearly ten years (2002–2011 confirm that a strong decrease of the polarisation ratio (i.e. signature of hoar disappearance is associated with an increase of wind speed or a change in wind direction from the prevailing direction. The photography data provides, in addition, evidence of interactions between hoar and snowfall. Further adding the combined influence of wind speed and wind direction results in a

  20. Arctic Sea ice by passive microwave observations from the Nimbus-5 Satellite

    Science.gov (United States)

    Campbell, W. J.; Gloersen, P.; Zwally, H. J.

    1983-01-01

    The results of a dynamic/thermodynamic numerical model of Arctic sea ice are compared with satellite images from the Nimbus 5 electrically scanning microwave radiometer. The model combines aspects of two previous sea ice models those of Parkinson and Washington and Ling, Rasmussen, and Campbell. A solid/fluid model basically follows the formulation of the Parkinson and Washington model with the addition of the constitutive equation and equation of state from the Ling model. The Parkinson and Washington model simulates the seasonal cycle of sea ice thicknesses and concentrations with a horizontal resolution of roughly 200 km and a timestep of 8 hours. The thermodynamics are calculated through energy balances at the interfaces between ice and air, water and ice, and water and air. The ice dynamics are calculated through a momentum equation balancing air stress, water stress, dynamic topography, and Coriolis force, with an adjustment for internal ice resistance.

  1. Optimization of Transition Edge Sensor Arrays for Cosmic Microwave Background Observations With the South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Junjia; Ade, P. A. R.; Anderson, A. J.; Avva, J.; Ahmed, Z.; Arnold, K.; Austermann, J. E.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Byrum, K.; Carlstrom, J. E.; Carter, F. W.; Chang, C. L.; Cho, H. M.; Cliche, J. F.; Cukierman, A.; Czaplewski, D.; Divan, R.; de Haan, T.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Gilbert, A.; Gannon, R.; Guyser, R.; Halverson, N. W.; Harrington, N. L.; Hattori, K.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Hubmayr, J.; Huang, N.; Irwin, K. D.; Jeong, O.; Khaire, T.; Kubik, D.; Kuo, C. L.; Lee, A. T.; Leitch, E. M.; Meyer, S. S.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Shariff, J. A.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J.; Stan, L.; Stark, A. A.; Story, K.; Suzuki, A.; Tang, Q. Y.; Thakur, R. B.; Thompson, K. L.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Wu, W. L. K.; Yefremenko, V.; Yoon, K. W.

    2017-06-01

    In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South PoleTelescope. The camera, which contains similar to 16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs.

  2. Demodulation effect is observed in neurones by exposure to low frequency modulated microwaves

    Science.gov (United States)

    Pérez-Bruzón, R. N.; Figols, T.; Azanza, M. J.; del Moral, A.

    2010-01-01

    Neurones exposure to a microwave (carrier fc=13.6 GHz; power P simeq 5 mW; Ho simeq 0.10 Am-1 = 1.25 mOe; E0 simeq 3.5 V/m; ΔT simeq 0.01°C SAR: 3.1×10-3 - 5.8×10-3 W/Kg) EMF amplitude modulated by ELF-AC field (frequency, fm= 0-100 Hz) shows no electrophysiological effect under the carrier MF alone, but "frequency resonances: at 2, 4, 8, 12, 16, 50, 100 Hz: demodulation effect. Resonances appear when applied ELF-MF is close to a dominant characteristic frequency of the neurone impulse Fourier spectrum. This is an interesting result considering that ELF-MF modulating RF or MW in the range of human EEG could induce frequency-resonant effects on exposed human brain.

  3. Mesospheric water vapor. Variability at different timescales observed by ground-based microwave spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hallgren, Kristofer

    2011-07-01

    The importance of water vapor in Earth's atmosphere cannot be understated. It is an active green-house gas, important energy conveyer in the troposhere and a key element in many chemical reactions in the middle atmosphere. Yet, there are still many questions concerning the water vapor dynamics in the middle atmosphere. This thesis present a new, state-of-the art, microwave instrument developed in order to shed light on some of these issues. The high sensitivity and time-resolution enable us to resolve fast dynamical events which was not possible before. Furthermore it expands an already long dataset and a mean vertical distribution of water vapor for polar latitudes is presented. (orig.)

  4. Observations of water vapor by ground-based micro-wave radiometers and Raman lidar

    Science.gov (United States)

    Han, Yong; Snider, J. B.; Westwater, E. R.; Melfi, S. H.; Ferrare, R. A.

    1994-09-01

    In November to December 1991, a substantial number of remote sensors and in situ instruments were operated together in Coffeyville, Kansas, during the climate experiment FIRE II. Included in the suite of instruments were (1) the NOAA Environmental Technology Laboratory (ETL) three-channel microwave radiometer, (2) the NASA GSFC Raman lidar, (3) ETL radio acoustic sounding system (RASS), and (4) frequent, research-quality radiosondes. The Raman lidar operated only at night and the focus of this portion of the experiment concentrated on clear conditions. The lidar data, together with frequent radiosondes and measurements of temperature profiles (every 15 min) by RASS allowed profiles of temperature and absolute humidity to be estimated every minute. We compared 2-min measurements of brightness temperature (Tb) with calculations of Tb that were based on the Liebe and Lay ton (1987) and Liebe et al. (1993) microwave propagation models, as well as the Waters (1976) model. The comparisons showed the best agreement at 20.6 GHz with the Waters model, with the Liebe et al. (1993) model being best at 31.65 GHz. The results at 90 GHz gave about equal success with the Liebe and Layton (1987) and Liebe et al. (1993) models. Comparisons of precipitable water vapor derived independently from the two instruments also showed excellent agreement, even for averages as short as 2 min. The rms difference between Raman and radiometric determinations of precipitable water vapor was 0.03 cm which is roughly 2%. The experiments clearly demonstrate the potential of simultaneous operation of radiometers and Raman lidars for fundamental physical studies of water vapor.

  5. Microwave Signatures of Melting/Refreezing Snow: Observations and Modeling Using Dense Medium Radiative Transfer Theory

    Science.gov (United States)

    Tedesco, Marco; Kim, Edward J.; England, Anthony; deRoo, Roger; Hardy, Janet

    2005-01-01

    Microwave brightness temperatures of snow covered terrains can be modeled by means of the Dense Radiative Transfer Medium Theory (DMRT). In a dense medium, such as snow, the assumption of independent scattering is no longer valid and the scattering of correlated scatterers must be considered. In the DMRT, this is done considering a pair distribution function of the particles position. In the electromagnetic model, the snowpack is simulated as a homogeneous layer having effective permittivity and albedo calculated through the DMRT. In order to account for clustering of snow crystals, a model of cohesive particles can be applied, where the cohesion between the particles is described by means of a dimensionless parameters called stickiness (z), representing a measure of the inversion of the attraction of the particles. The lower the z the higher the stickiness. In this study, microwave signatures of melting and refreezing cycles of seasonal snowpacks at high altitudes are studied by means of both experimental and modeling tools. Radiometric data were collected 24 hours per day by the University of Michigan Tower Mounted Radiometer System (TMRS). The brightness temperatures collected by means of the TMRS are simulated by means of a multi-layer electromagnetic model based on the dense medium theory with the inputs to the model derived from the data collected at the snow pits and from the meteorological station. The paper is structured as follows: in the first Section the temperature profiles recorded by the meteorological station and the snow pit data are presented and analyzed; in the second Section, the characteristics of the radiometric system used to collect the brightness temperatures are reported together with the temporal behavior of the recorded brightness temperatures; in the successive Section the multi-layer DMRT-based electromagnetic model is described; in the fourth Section the comparison between modeled and measured brightness temperatures is discussed. We

  6. Mesoscale and synoptic scale features of North Pacific weather systems observed with the scanning multichannel microwave radiometer on Nimbus 7

    Science.gov (United States)

    Katsaros, K. B.; Lewis, R. M.

    1986-01-01

    Employing data on integrated atmospheric water vapor, total cloud liquid water and rain rate obtainable from the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR), the frontal structure of several mid-latitude cyclones over the North Pacific Ocean as they approach the West Coast of North America in the winter of 1979. The fronts, analyzed with all available independent data, are consistently located at the leading edge of the strongest gradient in integrated water vapor. The cloud liquid water content, which unfortunately has received very little in situ verification, has patterns which are consistent with the structure seen in visible and infrared imagery. The rain distribution is also a good indicator of frontal location and rain amounts are generally within a factor of two of what is observed with rain gauges on the coast. Furthermore, the onset of rain on the coast can often be accurately forecast by simple advection of the SMMR observed rain areas.

  7. A global satellite environmental data record derived from AMSR-E and AMSR2 microwave Earth observations

    Science.gov (United States)

    Du, Jinyang; Kimball, John S.; Jones, Lucas A.; Kim, Youngwook; Glassy, Joseph; Watts, Jennifer D.

    2017-11-01

    Spaceborne microwave remote sensing is widely used to monitor global environmental changes for understanding hydrological, ecological, and climate processes. A new global land parameter data record (LPDR) was generated using similar calibrated, multifrequency brightness temperature (Tb) retrievals from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and the Advanced Microwave Scanning Radiometer 2 (AMSR2). The resulting LPDR provides a long-term (June 2002-December 2015) global record of key environmental observations at a 25 km grid cell resolution, including surface fractional open water (FW) cover, atmosphere precipitable water vapor (PWV), daily maximum and minimum surface air temperatures (Tmx and Tmn), vegetation optical depth (VOD), and surface volumetric soil moisture (VSM). Global mapping of the land parameter climatology means and seasonal variability over the full-year records from AMSR-E (2003-2010) and AMSR2 (2013-2015) observation periods is consistent with characteristic global climate and vegetation patterns. Quantitative comparisons with independent observations indicated favorable LPDR performance for FW (R ≥ 0.75; RMSE ≤ 0.06), PWV (R ≥ 0.91; RMSE ≤ 4.94 mm), Tmx and Tmn (R ≥ 0.90; RMSE ≤ 3.48 °C), and VSM (0.63 ≤ R ≤ 0.84; bias-corrected RMSE ≤ 0.06 cm3 cm-3). The LPDR-derived global VOD record is also proportional to satellite-observed NDVI (GIMMS3g) seasonality (R ≥ 0.88) due to the synergy between canopy biomass structure and photosynthetic greenness. Statistical analysis shows overall LPDR consistency but with small biases between AMSR-E and AMSR2 retrievals that should be considered when evaluating long-term environmental trends. The resulting LPDR and potential updates from continuing AMSR2 operations provide for effective global monitoring of environmental parameters related to vegetation activity, terrestrial water storage, and mobility and are suitable for climate and ecosystem studies. The LPDR dataset

  8. Limited list for the objects - candidates for SETI-monitoring with large telescopes

    Science.gov (United States)

    Panov, Alexander; Filippova, Lilia; Rudnitskii, Georgiii

    There are about one million stars within one thousand light years region around the Sun that may have habitable planets and which are interesting from the point of view of the SETI problem. All these stars are acceptable in principle for monitoring with large radio telescopes with aim to catch a radio message from aliens but it is still impossible to monitor all of them due to a lack of special instruments designed for SETI like large antenna arrays. In this situation we propose a special limited list of especially interesting objects to monitor with using of usual large radio telescopes in accompanying mode together with usual astrophysical observations. This list consists of the objects of three types and there are only about three dozen objects in total in the list. The first type of objects is represented by sunlike stars satisfying the following criteria: 1) The spectral type is from F8V to K0V; 2) The estimate of the age of the star is from 4 to 6 billions of years; 3) The distance from the Sun is less than 100 light years; 4) The radial velocity is less than 50 km/sec; 5) If it is known the star to have planets, then the eccentricity of orbits is less than 0.2. The special interest among the sunlike stars satisfying the criteria 1-5 are the near-ecliptic ones, since the Earth is seen from them as a transit planet, therefore the solar system may be a preferable target to send a message for aliens from planets of such stars. The second type of objects is a number of stars that are targets of already sent space messages and at the same time which are sunlike stars satisfying the criteria 1-5. Moreover some slow narrow-band radio signal above background was observed previously from one of the second type object and the result should be verified. The objects of the third class are not stars, but they are globular clusters. We elaborate a number of criteria to select globular clusters but emphasize a high level of metallicity. Many stars in such globular clusters

  9. NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: COSMOLOGICAL PARAMETER RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Hinshaw, G.; Halpern, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Larson, D.; Bennett, C. L.; Weiland, J. L. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Komatsu, E. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, D-85741 Garching (Germany); Spergel, D. N. [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, University of Tokyo, Kashiwa 277-8583 (Japan); Dunkley, J. [Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Nolta, M. R. [Canadian Institute for Theoretical Astrophysics, 60 St. George St., University of Toronto, Toronto, ON M5S 3H8 (Canada); Hill, R. S.; Odegard, N. [ADNET Systems, Inc., 7515 Mission Dr., Suite A100 Lanham, MD 20706 (United States); Page, L.; Jarosik, N. [Department of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544-0708 (United States); Smith, K. M. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544-1001 (United States); Gold, B. [University of Minnesota, School of Physics and Astronomy, 116 Church Street S.E., Minneapolis, MN 55455 (United States); Kogut, A.; Wollack, E. [Code 665, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Limon, M. [Columbia Astrophysics Laboratory, 550 W. 120th St., Mail Code 5247, New York, NY 10027-6902 (United States); Meyer, S. S. [Departments of Astrophysics and Physics, KICP and EFI, University of Chicago, Chicago, IL 60637 (United States); Tucker, G. S., E-mail: hinshaw@physics.ubc.ca [Department of Physics, Brown University, 182 Hope St., Providence, RI 02912-1843 (United States); and others

    2013-10-01

    We present cosmological parameter constraints based on the final nine-year Wilkinson Microwave Anisotropy Probe (WMAP) data, in conjunction with a number of additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter ΛCDM model. When WMAP data are combined with measurements of the high-l cosmic microwave background anisotropy, the baryon acoustic oscillation scale, and the Hubble constant, the matter and energy densities, Ω {sub b} h {sup 2}, Ω {sub c} h {sup 2}, and Ω{sub Λ}, are each determined to a precision of ∼1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5σ level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional ΛCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their ΛCDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r < 0.13 (95% CL); the spatial curvature parameter is limited to Ω{sub k} = -0.0027{sup +0.0039}{sub -0.0038}; the summed mass of neutrinos is limited to Σm {sub ν} < 0.44 eV (95% CL); and the number of relativistic species is found to lie within N {sub eff} = 3.84 ± 0.40, when the full data are analyzed. The joint constraint on N {sub eff} and the primordial helium abundance, Y {sub He}, agrees with the prediction of standard big bang nucleosynthesis. We compare recent Planck measurements of the Sunyaev-Zel'dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard

  10. FUSION OF ACTIVE AND PASSIVE MICROWAVE OBSERVATIONS TO CREATE AN ESSENTIAL CLIMATE VARIABLE DATA RECORD ON SOIL MOISTURE

    Directory of Open Access Journals (Sweden)

    W. Wagner

    2012-07-01

    Full Text Available Soil moisture was recently included in the list of Essential Climate Variables (ECVs that are deemed essential for IPCC (Intergovernmental Panel on Climate Change and UNFCCC (United Nations Framework Convention on Climate Change needs and considered feasible for global observation. ECVs data records should be as long, complete and consistent as possible, and in the case of soil moisture this means that the data record shall be based on multiple data sources, including but not limited to active (scatterometer and passive (radiometer microwave observations acquired preferably in the low-frequency microwave range. Among the list of sensors that can be used for this task are the C-band scatterometers on board of the ERS and METOP satellites and the multi-frequency radiometers SMMR, SSM/I, TMI, AMSR-E, and Windsat. Together, these sensors already cover a time period of more than 30 years and the question is how can observations acquired by these sensors be merged to create one consistent data record? This paper discusses on a high-level possible approaches for fusing the individual satellite data. It is argued that the best possible approach for the fusion of the different satellite data sets is to merge Level 2 soil moisture data derived from the individual satellite data records. This approach has already been demonstrated within the WACMOS project (http://wacmos.itc.nl/ funded by European Space Agency (ESA and will be further improved within the Climate Change Initiative (CCI programme of ESA (http://www.esa-cci.org/.

  11. Quantitative Precipitation Estimation over Ocean Using Bayesian Approach from Microwave Observations during the Typhoon Season

    Directory of Open Access Journals (Sweden)

    Jen-Chi Hu

    2009-01-01

    Full Text Available We have developed a new Bayesian approach to retrieve oceanic rain rate from the Tropical Rainfall Measuring Mission (TRMM Microwave Imager (TMI, with an emphasis on typhoon cases in the West Pacific. Retrieved rain rates are validated with measurements of rain gauges located on Japanese islands. To demonstrate improvement, retrievals are also compared with those from the TRMM/Precipitation Radar (PR, the Goddard Profiling Algorithm (GPROF, and a multi-channel linear regression statistical method (MLRS. We have found that qualitatively, all methods retrieved similar horizontal distributions in terms of locations of eyes and rain bands of typhoons. Quantitatively, our new Bayesian retrievals have the best linearity and the smallest root mean square (RMS error against rain gauge data for 16 typhoon over passes in 2004. The correlation coefficient and RMS of our retrievals are 0.95 and ~2 mm hr-1, respectively. In particular, at heavy rain rates, our Bayesian retrievals out perform those retrieved from GPROF and MLRS. Over all, the new Bayesian approach accurately retrieves surface rain rate for typhoon cases. Ac cu rate rain rate estimates from this method can be assimilated in models to improve forecast and prevent potential damages in Taiwan during typhoon seasons.

  12. The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations

    Science.gov (United States)

    Kogut, Alan J.; Fixsen, D. J.; Chuss, D. T.; Dotson, J.; Dwek, E.; Halpern, M.; Hinshaw, G. F.; Meyer, S. M.; Moseley, S. H.; Seiffert, M. D.; hide

    2011-01-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10..3 at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  13. Demodulation effect is observed in neurones by exposure to low frequency modulated microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Bruzon, R N; Figols, T; Azanza, M J [Laboratorio de Magnetobiologia, Departamento de Anatomia e Histologia Humanas, Facultad de Medicina, Universidad de Zaragoza (Spain); Moral, A del, E-mail: naogit@yahoo.co [Laboratorio de Magnetismo de Solidos, Departamento de Fisica de Materia Condensada and Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza and CSIC (Spain)

    2010-01-01

    Neurones exposure to a microwave (carrier f{sub c}=13.6 GHz; power P {approx_equal} 5 mW; H{sub o} {approx_equal} 0.10 Am{sup -1} = 1.25 mOe; E{sub 0} {approx_equal} 3.5 V/m; {Delta}T {approx_equal} 0.01{sup 0}C; SAR: 3.1x10{sup -3} - 5.8x10{sup -3} W/Kg) EMF amplitude modulated by ELF-AC field (frequency, f{sub m}= 0-100 Hz) shows no electrophysiological effect under the carrier MF alone, but {sup f}requency resonances: at 2, 4, 8, 12, 16, 50, 100 Hz: demodulation effect. Resonances appear when applied ELF-MF is close to a dominant characteristic frequency of the neurone impulse Fourier spectrum. This is an interesting result considering that ELF-MF modulating RF or MW in the range of human EEG could induce frequency-resonant effects on exposed human brain.

  14. An EOF-based comparison and evaluation of simulated passive microwave signatures to observations over tropical oceans

    Science.gov (United States)

    Biggerstaff, Michael I.; Seo, Eun-Kyoung

    2010-08-01

    Bayesian algorithms are a common method of retrieving cloud properties from a set of observed passive microwave brightness temperature (TB) measurements. In practice, such methods often use predefined databases from cloud-resolving models to perform the retrieval. Successful performance in these types of Bayesian retrievals is greatly affected by the similarity of TBs between observed and predefined databases. Here empirical orthogonal function (EOF) analysis methods were used to illustrate the importance of predefined simulation databases on the ability to retrieve known regional variability in cloud structures across different parts of the tropical oceans and to provide insight on the relative impact of environmental conditions to limitations in cloud model microphysical parameterizations in retrieving different types of cloud structures. The spatial distributions of EOF coefficients in EOF space showed that there were both underrepresentation and overrepresentation between manifolds of the predefined and observed databases. Moreover, there was poor alignment in the frequency distribution between observed and simulated clouds structures. Additionally, the ability to retrieve known regional variability in convective cloud structure was dependent on the environmental conditions used to generate the simulated data set more so than limitations in the model microphysical parameterizations. The opposite was true for stratiform rain, as the dominant EOF patterns of the radiation indices for the predefined databases exhibit overproduction of large-sized high-density ice-phase hydrometeors for a given rain content in comparison to the observations. Improvements to microphysical parameterization schemes appear to be necessary to produce radiance index vectors that are consistent with observations.

  15. Simulation of polar atmospheric microwave and sub-millimetre spectra for characterizing potential new ground-based observations

    Science.gov (United States)

    Newnham, David; Turner, Emma; Ford, George; Pumphrey, Hugh; Withington, Stafford

    2016-04-01

    Advanced detector technologies from the fields of astronomy and telecommunications are offering the potential to address key atmospheric science challenges with new instrumental methods. Adoption of these technologies in ground-based passive microwave and sub-millimetre radiometry could allow new measurements of chemical species and winds in the polar middle atmosphere for verifying meteorological data-sets and atmospheric models. A site study to assess the feasibility of new polar observations is performed by simulating the downwelling clear-sky submillimetre spectrum over 10-2000 GHz (30 mm to 150 microns) at two Arctic and two Antarctic locations under different seasonal and diurnal conditions. Vertical profiles for temperature, pressure and 28 atmospheric gases are constructed by combining radiosonde, meteorological reanalysis, and atmospheric chemistry model data. The sensitivity of the simulated spectra to the choice of water vapour continuum model and spectroscopic line database is explored. For the atmospheric trace species hypobromous acid (HOBr), hydrogen bromide (HBr), perhydroxyl radical (HO2) and nitrous oxide (N2O) the emission lines producing the largest change in brightness temperature are identified and minimum integration times and maximum receiver noise temperatures estimated. The optimal lines for all species are shown to vary significantly between location and scenario, strengthening the case for future hyperspectral instruments that measure over a broad frequency range. We also demonstrate the feasibility of measuring horizontal wind profiles above Halley station, Antarctica with time resolution as high as 0.5hr using simulated spectroradiometric observations of Doppler-shifted ozone (O3) and carbon monoxide (CO) lines in the 230-250 GHz region. The techniques presented provide a framework that can be applied to the retrieval of additional atmospheric parameters and be taken forward to simulate and guide the design of future microwave and sub

  16. Toward understanding the active SETI debate: Insights from risk communication and perception

    Science.gov (United States)

    Korbitz, Adam

    2014-12-01

    Insights from the robust field of risk communication and perception have to date been almost totally absent from the policy debate regarding the relative risks and merits of Active SETI or Messaging to Extraterrestrial Intelligence (METI). For many years, the practice (or proposed practice) of Active SETI has generated a vigorous and sometimes heated policy debate within the scientific community. There have also been some negative reactions in the media toward the activities of those engaged in Active SETI. Risk communication is a scientific approach to communication regarding situations involving potentially sensitive or controversial situations in which there may be high public concern and low public trust. The discipline has found wide acceptance and utility in fields such as public health, industrial regulation and environmental protection. Insights from the scientific field of risk communication (such as omission bias, loss aversion, the availability heuristic, probability neglect, and the general human preference for voluntary over involuntary risks) may help those who have participated in either side of the debate over Active SETI to better understand why the debate has taken on this posture. Principles of risk communication and risk perception may also help those engaged in Active SETI to communicate more effectively with other scientists, the public, with the media, and with policy makers regarding their activities and to better understand and respond to concerns expressed regarding the activity.

  17. Microwave tomography for an effective imaging in GPR on UAV/airborne observational platforms

    Science.gov (United States)

    Soldovieri, Francesco; Catapano, Ilaria; Ludeno, Giovanni

    2017-04-01

    GPR was originally thought as a non-invasive diagnostics technique working in contact with the underground or structure to be investigated. On the other hand, in the recent years several challenging necessities and opportunities entail the necessity to work with antenna not in contact with the structure to be investigated. This necessity arises for example in the case of landmine detection but also for cultural heritage diagnostics. Other field of application regards the forward-looking GPR aiming at shallower hidden targets forward the platfrom (vehicle) carrying the GPR [1]. Finally, a recent application is concerned with the deployment of airborne/UAV GPR, able to ensure several advantages in terms of large scale surveys and "freedom" of logistics constraint [2]. For all the above mentioned cases, the interest is towards the development of effective data processing able to make imaging task in real time. The presentation will show different data processing strategies, based on microwave tomography [1,2], for a reliable and real time imaging in the case of GPR platforms far from the interface of the structure/underground to be investigated. [1] I. Catapano, A. Affinito, A. Del Moro,.G. Alli, and F. Soldovieri, "Forward-Looking Ground-Penetrating Radar via a Linear Inverse Scattering Approach," IEEE Transactions on Geoscience and Remote Sensing, vol. 53, pp. 5624 - 5633, Oct. 2015. [2] I. Catapano, L. Crocco, Y. Krellmann, G. Triltzsch, and F. Soldovieri, "A tomographic approach for helicopter-borne ground penetrating radar imaging," IEEE Geosci. Remote Sens. Lett., vol. 9, no. 3, pp. 378-382, May 2012.

  18. Uncertainties of ground-based microwave radiometer retrievals in zenith and off-zenith observations under snow conditions

    Science.gov (United States)

    Zhang, Wengang; Xu, Guirong; Liu, Yuanyuan; Yan, Guopao; Li, Dejun; Wang, Shengbo

    2017-01-01

    This paper is to investigate the uncertainties of microwave radiometer (MWR) retrievals in snow conditions and also explore the discrepancies of MWR retrievals in zenith and off-zenith observations. The MWR retrievals were averaged in a ±15 min period centered at sounding times of 00:00 and 12:00 UTC and compared with radiosonde observations (RAOBs). In general, the MWR retrievals have a better correlation with RAOB profiles in off-zenith observations than in zenith observations, and the biases (MWR observations minus RAOBs) and root mean square errors (RMSEs) between MWR and RAOB are also clearly reduced in off-zenith observations. The biases of temperature, relative humidity, and vapor density decrease from 4.6 K, 9 %, and 1.43 g m-3 in zenith observations to -0.6 K, -2 %, and 0.10 g m-3 in off-zenith observations, respectively. The discrepancies between MWR retrievals and RAOB profiles by altitude present the same situation. Cases studies show that the impact of snow on accuracies of MWR retrievals is more serious in heavy snowfall than in light snowfall, but off-zenith observation can mitigate the impact of snowfall. The MWR measurements become less accurate in snowfall mainly due to the retrieval algorithm, which does not consider the effect of snow, and the accumulated snow on the top of the radome increases the signal noise of MWR measurements. As the snowfall drops away by gravity on the sides of the radome, the off-zenith observations are more representative of the atmospheric conditions for RAOBs.

  19. Evo-SETI SCALE to measure Life on Exoplanets

    Science.gov (United States)

    Maccone, Claudio

    2016-04-01

    Darwinian Evolution over the last 3.5 billion years was an increase in the number of living species from 1 (RNA?) to the current 50 million. This increasing trend in time looks like being exponential, but one may not assume an exactly exponential curve since many species went extinct in the past, even in mass extinctions. Thus, the simple exponential curve must be replaced by a stochastic process having an exponential mean value. Borrowing from financial mathematics (;Black-Scholes models;), this ;exponential; stochastic process is called Geometric Brownian Motion (GBM), and its probability density function (pdf) is a lognormal (not a Gaussian) (Proof: see ref. Maccone [3], Chapter 30, and ref. Maccone [4]). Lognormal also is the pdf of the statistical number of communicating ExtraTerrestrial (ET) civilizations in the Galaxy at a certain fixed time, like a snapshot: this result was found in 2008 by this author as his solution to the Statistical Drake Equation of SETI (Proof: see ref. Maccone [1]). Thus, the GBM of Darwinian Evolution may also be regarded as the extension in time of the Statistical Drake equation (Proof: see ref. Maccone [4]). But the key step ahead made by this author in his Evo-SETI (Evolution and SETI) mathematical model was to realize that LIFE also is just a b-lognormal in time: every living organism (a cell, a human, a civilization, even an ET civilization) is born at a certain time b (;birth;), grows up to a peak p (with an ascending inflexion point in between, a for adolescence), then declines from p to s (senility, i.e. descending inflexion point) and finally declines linearly and dies at a final instant d (death). In other words, the infinite tail of the b-lognormal was cut away and replaced by just a straight line between s and d, leading to simple mathematical formulae (;History Formulae;) allowing one to find this ;finite b-lognormal; when the three instants b, s, and d are assigned. Next the crucial Peak-Locus Theorem comes. It means

  20. A 10-Year Cloud Fraction Climatology of Liquid Water Clouds over Bern Observed by a Ground-Based Microwave Radiometer

    Directory of Open Access Journals (Sweden)

    Federico Cossu

    2015-06-01

    Full Text Available Cloud fraction (CF is known as the dominant modulator of Earth’s radiative fluxes. Ground-based CF observations are useful to characterize the cloudiness of a specific site and are valuable for comparison with satellite observations and numerical models. We present for the first time CF statistics (relative to liquid clouds only for Bern, Switzerland, derived from the observations of a ground-based microwave radiometer. CF is derived with a new method involving the analysis of the integrated liquid water distribution measured by the radiometer. The 10-year analyzed period (2004–2013 allowed us to compute a CF climatology for Bern, showing a maximum CF of 60.9% in winter and a minimum CF of 42.0% in summer. The CF monthly anomalies are identified with respect to the climatological mean values, and they are confirmed through MeteoSwiss yearly climatological bulletins. The CF monthly mean variations are similar to the observations taken at another Swiss location, Payerne, suggesting a large-scale correlation between different sites on the Swiss Plateau. A CF diurnal cycle is also computed, and large intraseasonal variations are found. The overall mean CF diurnal cycle, however, shows a typical sinusoidal cycle, with higher values in the morning and lower values in the afternoon.

  1. Ground-based microwave radar and optical lidar signatures of volcanic ash plumes: models, observations and retrievals

    Science.gov (United States)

    Mereu, Luigi; Marzano, Frank; Mori, Saverio; Montopoli, Mario; Cimini, Domenico; Martucci, Giovanni

    2013-04-01

    The detection and quantitative retrieval of volcanic ash clouds is of significant interest due to its environmental, climatic and socio-economic effects. Real-time monitoring of such phenomena is crucial, also for the initialization of dispersion models. Satellite visible-infrared radiometric observations from geostationary platforms are usually exploited for long-range trajectory tracking and for measuring low level eruptions. Their imagery is available every 15-30 minutes and suffers from a relatively poor spatial resolution. Moreover, the field-of-view of geostationary radiometric measurements may be blocked by water and ice clouds at higher levels and their overall utility is reduced at night. Ground-based microwave radars may represent an important tool to detect and, to a certain extent, mitigate the hazard from the ash clouds. Ground-based weather radar systems can provide data for determining the ash volume, total mass and height of eruption clouds. Methodological studies have recently investigated the possibility of using ground-based single-polarization and dual-polarization radar system for the remote sensing of volcanic ash cloud. A microphysical characterization of volcanic ash was carried out in terms of dielectric properties, size distribution and terminal fall speed, assuming spherically-shaped particles. A prototype of volcanic ash radar retrieval (VARR) algorithm for single-polarization systems was proposed and applied to S-band and C-band weather radar data. The sensitivity of the ground-based radar measurements decreases as the ash cloud is farther so that for distances greater than about 50 kilometers fine ash might be not detected anymore by microwave radars. In this respect, radar observations can be complementary to satellite, lidar and aircraft observations. Active remote sensing retrieval from ground, in terms of detection, estimation and sensitivity, of volcanic ash plumes is not only dependent on the sensor specifications, but also on

  2. Global Precipitation Estimates from Cross-Track Passive Microwave Observations Using a Physically-Based Retrieval Scheme

    Science.gov (United States)

    Kidd, Chris; Matsui, Toshi; Chern, Jiundar; Mohr, Karen; Kummerow, Christian; Randel, Dave

    2015-01-01

    The estimation of precipitation across the globe from satellite sensors provides a key resource in the observation and understanding of our climate system. Estimates from all pertinent satellite observations are critical in providing the necessary temporal sampling. However, consistency in these estimates from instruments with different frequencies and resolutions is critical. This paper details the physically based retrieval scheme to estimate precipitation from cross-track (XT) passive microwave (PM) sensors on board the constellation satellites of the Global Precipitation Measurement (GPM) mission. Here the Goddard profiling algorithm (GPROF), a physically based Bayesian scheme developed for conically scanning (CS) sensors, is adapted for use with XT PM sensors. The present XT GPROF scheme utilizes a model-generated database to overcome issues encountered with an observational database as used by the CS scheme. The model database ensures greater consistency across meteorological regimes and surface types by providing a more comprehensive set of precipitation profiles. The database is corrected for bias against the CS database to ensure consistency in the final product. Statistical comparisons over western Europe and the United States show that the XT GPROF estimates are comparable with those from the CS scheme. Indeed, the XT estimates have higher correlations against surface radar data, while maintaining similar root-mean-square errors. Latitudinal profiles of precipitation show the XT estimates are generally comparable with the CS estimates, although in the southern midlatitudes the peak precipitation is shifted equatorward while over the Arctic large differences are seen between the XT and the CS retrievals.

  3. Using microwave observations to estimate land surface temperature during cloudy conditions

    Science.gov (United States)

    Land surface temperature (LST), a key ingredient for physically-based retrieval algorithms of hydrological states and fluxes, remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and...

  4. Analysis and evaluation of WRF microphysical schemes for deep moist convection over south-eastern South America (SESA using microwave satellite observations and radiative transfer simulations

    Directory of Open Access Journals (Sweden)

    V. S. Galligani

    2017-10-01

    Full Text Available In the present study, three meteorological events of extreme deep moist convection, characteristic of south-eastern South America, are considered to conduct a systematic evaluation of the microphysical parameterizations available in the Weather Research and Forecasting (WRF model by undertaking a direct comparison between satellite-based simulated and observed microwave radiances. A research radiative transfer model, the Atmospheric Radiative Transfer Simulator (ARTS, is coupled with the WRF model under three different microphysical parameterizations (WSM6, WDM6 and Thompson schemes. Microwave radiometry has shown a promising ability in the characterization of frozen hydrometeors. At high microwave frequencies, however, frozen hydrometeors significantly scatter radiation, and the relationship between radiation and hydrometeor populations becomes very complex. The main difficulty in microwave remote sensing of frozen hydrometeor characterization is correctly characterizing this scattering signal due to the complex and variable nature of the size, composition and shape of frozen hydrometeors. The present study further aims at improving the understanding of frozen hydrometeor optical properties characteristic of deep moist convection events in south-eastern South America. In the present study, bulk optical properties are computed by integrating the single-scattering properties of the Liu(2008 discrete dipole approximation (DDA single-scattering database across the particle size distributions parameterized by the different WRF schemes in a consistent manner, introducing the equal mass approach. The equal mass approach consists of describing the optical properties of the WRF snow and graupel hydrometeors with the optical properties of habits in the DDA database whose dimensions might be different (Dmax′ but whose mass is conserved. The performance of the radiative transfer simulations is evaluated by comparing the simulations with the available

  5. Analysis and evaluation of WRF microphysical schemes for deep moist convection over south-eastern South America (SESA) using microwave satellite observations and radiative transfer simulations

    Science.gov (United States)

    Sol Galligani, Victoria; Wang, Die; Alvarez Imaz, Milagros; Salio, Paola; Prigent, Catherine

    2017-10-01

    In the present study, three meteorological events of extreme deep moist convection, characteristic of south-eastern South America, are considered to conduct a systematic evaluation of the microphysical parameterizations available in the Weather Research and Forecasting (WRF) model by undertaking a direct comparison between satellite-based simulated and observed microwave radiances. A research radiative transfer model, the Atmospheric Radiative Transfer Simulator (ARTS), is coupled with the WRF model under three different microphysical parameterizations (WSM6, WDM6 and Thompson schemes). Microwave radiometry has shown a promising ability in the characterization of frozen hydrometeors. At high microwave frequencies, however, frozen hydrometeors significantly scatter radiation, and the relationship between radiation and hydrometeor populations becomes very complex. The main difficulty in microwave remote sensing of frozen hydrometeor characterization is correctly characterizing this scattering signal due to the complex and variable nature of the size, composition and shape of frozen hydrometeors. The present study further aims at improving the understanding of frozen hydrometeor optical properties characteristic of deep moist convection events in south-eastern South America. In the present study, bulk optical properties are computed by integrating the single-scattering properties of the Liu(2008) discrete dipole approximation (DDA) single-scattering database across the particle size distributions parameterized by the different WRF schemes in a consistent manner, introducing the equal mass approach. The equal mass approach consists of describing the optical properties of the WRF snow and graupel hydrometeors with the optical properties of habits in the DDA database whose dimensions might be different (Dmax') but whose mass is conserved. The performance of the radiative transfer simulations is evaluated by comparing the simulations with the available coincident

  6. Towards an improved soil moisture retrieval for organic-rich soils from SMOS passive microwave L-band observations

    Science.gov (United States)

    Bircher, Simone; Richaume, Philippe; Mahmoodi, Ali; Mialon, Arnaud; Fernandez-Moran, Roberto; Wigneron, Jean-Pierre; Demontoux, François; Jonard, François; Weihermüller, Lutz; Andreasen, Mie; Rautiainen, Kimmo; Ikonen, Jaakko; Schwank, Mike; Drusch, Mattias; Kerr, Yann H.

    2017-04-01

    evaluated using the default dielectric model for mineral soils is ongoing for the "organic" L-MEB version. Additionally, in order to decide where a soil moisture retrieval using the "organic" dielectric model should be triggered, information on soil organic matter content in the soil surface layer has to be considered in the retrieval algorithm. For this purpose, SoilGrids (www.soilgrids.org) providing soil organic carbon content (SOCC) in g/kg is under study. A SOCC threshold based on the relation between the SoilGrids' SOCC and the presence of organic soil surface layers (relevant to alter the microwave L-band emissions from the land surface) in the SoilGrids' source soil profile information has to be established. In this communication, we present the current status of the above outlined studies with the objective to advance towards an improved soil moisture retrieval for organic-rich soils from SMOS passive microwave L-band observations.

  7. Energy of Extra-Terrestrial Civilizations according to Evo-SETI Theory

    Science.gov (United States)

    Maccone, Claudio

    2018-03-01

    Consider two great scientists of the past: Kepler (1571-1630) and Newton (1642-1727). Kepler discovered his three laws of planetary motion by observing Mars: he knew experimentally that his three laws were correct, but he didn't even suspect that all three mathematical laws could be derived as purely mathematical consequences by a "superior" mathematical law. The latter was the Law of Gravitation that Newton gave the world together with his supreme mathematical discovery of the Calculus, necessary for that mathematical derivation. We think we did the same for the "molecular clock", the experimental law of genetics discovered in 1962 by Émile Zuckerkandl (1922-2013) and Linus Pauling (1901-1994) and derived by us as a purely mathematical consequence of our mathematical Evo-SETI Theory. Let us now summarize how this mathematical derivation was achieved. Darwinian evolution over the last 3.5 billion years was an increase in the number of living species from one (RNA ?) to the current (say) 50 million. This increasing trend in time looks like being exponential, but one may not assume an exact exponential curve since many species went extinct in the past, especially in the five, big mass extinctions. Thus, the simple exponential curve must be replaced by a stochastic process having an exponential mean value. Borrowing from financial mathematics (the "Black-Sholes models"), this "exponential" stochastic process is called Geometric Brownian Motion (GBM). Its probability density function (pdf) is a lognormal (and not a Gaussian) (Proof: see Ref. [3], Chapter 30, and Ref. [4], and, more in general, refs. [2] and [5]). Lognormal also is the pdf of the statistical number of communicating ExtraTerrestrial (ET) civilizations in the Galaxy at a certain fixed time, like a snapshot: this result was obtained in 2008 by this author as his solution to the Statistical Drake Equation of SETI (Proof: see Ref. [1]). Thus, the GBM of Darwinian evolution may also be regarded as the

  8. Aura Microwave Limb Sounder Observations of Dynamics and Transport During the Record-Breaking 2009 Arctic Stratospheric Major Warming

    Science.gov (United States)

    Manney, Gloria L.; Schwartz, Michael J.; Krueger, Kirstin; Santee, Michelle L.; Pawson, Steven; Lee, Jae N.; Daffer, William H.; Fuller, Ryan A.; Livesey, Nathaniel J.

    2009-01-01

    A major stratospheric sudden warming (SSW) in January 2009 was the strongest and most prolonged on record. Aura Microwave Limb Sounder (MLS) observations are used to provide an overview of dynamics and transport during the 2009 SSW, and to compare with the intense, long-lasting SSW in January 2006. The Arctic polar vortex split during the 2009 SSW, whereas the 2006 SSW was a vortex displacement event. Winds reversed to easterly more rapidly and reverted to westerly more slowly in 2009 than in 2006. More mixing of trace gases out of the vortex during the decay of the vortex fragments, and less before the fulfillment of major SSW criteria, was seen in 2009 than in 2006; persistent well-defined fragments of vortex and anticyclone air were more prevalent in 2009. The 2009 SSW had a more profound impact on the lower stratosphere than any previously observed SSW, with no significant recovery of the vortex in that region. The stratopause breakdown and subsequent reformation at very high altitude, accompanied by enhanced descent into a rapidly strengthening upper stratospheric vortex, were similar in 2009 and 2006. Many differences between 2006 and 2009 appear to be related to the different character of the SSWs in the two years.

  9. Time-Evolution of a White Light Flare: Observations in Optical, Microwave, Soft X-Ray, H alpha

    Science.gov (United States)

    Lee, E.; Li, J.

    2003-12-01

    Since Richard Carrington's 1859 discovery of White Light Flares (WLFs), only fifty other WLFs have been observed. While the predicted frequency was 15.5 (± 4.5) per year for solar cycle 20, the lack of sensitive instruments makes WLFs extremely rare. Past observations suggest that WLFs do not accompany all high-energy events, and that some specific initial conditions and mechanisms produce WLFs. To analyze this claim, we found a WLF by combing through a list of X class events. This X5.6 flare occurred at AR 9415 on April 6th, 2001 (UT 19:14) and was accompanied by a halo CME. After confirming this event to be a WLF using Imaging Vector Magnetograph data, we found microwave, EUV, optical, soft X-ray, and magnetogram data. Our data suggests that this WLF erupted through the same mechanisms as the standard flare models, but was more energetic. This work was funded by the National Science Foundation's Research Experience for Undergraduates program.

  10. Assessing the Impact of Pre-gpm Microwave Precipitation Observations in the Goddard WRF Ensemble Data Assimilation System

    Science.gov (United States)

    Chambon, Philippe; Zhang, Sara Q.; Hou, Arthur Y.; Zupanski, Milija; Cheung, Samson

    2013-01-01

    The forthcoming Global Precipitation Measurement (GPM) Mission will provide next generation precipitation observations from a constellation of satellites. Since precipitation by nature has large variability and low predictability at cloud-resolving scales, the impact of precipitation data on the skills of mesoscale numerical weather prediction (NWP) is largely affected by the characterization of background and observation errors and the representation of nonlinear cloud/precipitation physics in an NWP data assimilation system. We present a data impact study on the assimilation of precipitation-affected microwave (MW) radiances from a pre-GPM satellite constellation using the Goddard WRF Ensemble Data Assimilation System (Goddard WRF-EDAS). A series of assimilation experiments are carried out in a Weather Research Forecast (WRF) model domain of 9 km resolution in western Europe. Sensitivities to observation error specifications, background error covariance estimated from ensemble forecasts with different ensemble sizes, and MW channel selections are examined through single-observation assimilation experiments. An empirical bias correction for precipitation-affected MW radiances is developed based on the statistics of radiance innovations in rainy areas. The data impact is assessed by full data assimilation cycling experiments for a storm event that occurred in France in September 2010. Results show that the assimilation of MW precipitation observations from a satellite constellation mimicking GPM has a positive impact on the accumulated rain forecasts verified with surface radar rain estimates. The case-study on a convective storm also reveals that the accuracy of ensemble-based background error covariance is limited by sampling errors and model errors such as precipitation displacement and unresolved convective scale instability.

  11. Evolution and History in a new "Mathematical SETI" model

    Science.gov (United States)

    Maccone, Claudio

    2014-01-01

    In a recent paper (Maccone, 2011 [15]) and in a recent book (Maccone, 2012 [17]), this author proposed a new mathematical model capable of merging SETI and Darwinian Evolution into a single mathematical scheme. This model is based on exponentials and lognormal probability distributions, called "b-lognormals" if they start at any positive time b ("birth") larger than zero. Indeed: Darwinian evolution theory may be regarded as a part of SETI theory in that the factor fl in the Drake equation represents the fraction of planets suitable for life on which life actually arose, as it happened on Earth. In 2008 (Maccone, 2008 [9]) this author firstly provided a statistical generalization of the Drake equation where the number N of communicating ET civilizations in the Galaxy was shown to follow the lognormal probability distribution. This fact is a consequence of the Central Limit Theorem (CLT) of Statistics, stating that the product of a number of independent random variables whose probability densities are unknown and independent of each other approached the lognormal distribution if the number of factors is increased at will, i.e. it approaches infinity. Also, in Maccone (2011 [15]), it was shown that the exponential growth of the number of species typical of Darwinian Evolution may be regarded as the geometric locus of the peaks of a one-parameter family of b-lognormal distributions constrained between the time axis and the exponential growth curve. This was a brand-new result. And one more new and far-reaching idea was to define Darwinian Evolution as a particular realization of a stochastic process called Geometric Brownian Motion (GBM) having the above exponential as its own mean value curve. The b-lognormals may be also be interpreted as the lifespan of any living being, let it be a cell, or an animal, a plant, a human, or even the historic lifetime of any civilization. In Maccone, (2012 [17, Chapters 6, 7, 8 and 11]), as well as in the present paper, we give

  12. SETI among galaxies by virtue of black holes

    Science.gov (United States)

    Maccone, Claudio

    2012-09-01

    respect to ordinary interstellar distances within the Milky Way, the black hole masses in the game are so much huger than the stellar masses than the intergalactic bridges perform better than the interstellar bridges. This unexpected and new result might have profound consequences on SETI done currently by Humans on Earth. In fact, more advanced civilizations might already have built such intergalactic radio-bridges. Thus our SETI searches should be tuned-up to match with this new situation, and the conclusion is that the possibility of SETI signals reaching us from other galaxies should not be ruled out.

  13. Long-term observations minus background monitoring of ground-based brightness temperatures from a microwave radiometer network

    Science.gov (United States)

    De Angelis, Francesco; Cimini, Domenico; Löhnert, Ulrich; Caumont, Olivier; Haefele, Alexander; Pospichal, Bernhard; Martinet, Pauline; Navas-Guzmán, Francisco; Klein-Baltink, Henk; Dupont, Jean-Charles; Hocking, James

    2017-10-01

    Ground-based microwave radiometers (MWRs) offer the capability to provide continuous, high-temporal-resolution observations of the atmospheric thermodynamic state in the planetary boundary layer (PBL) with low maintenance. This makes MWR an ideal instrument to supplement radiosonde and satellite observations when initializing numerical weather prediction (NWP) models through data assimilation. State-of-the-art data assimilation systems (e.g. variational schemes) require an accurate representation of the differences between model (background) and observations, which are then weighted by their respective errors to provide the best analysis of the true atmospheric state. In this perspective, one source of information is contained in the statistics of the differences between observations and their background counterparts (O-B). Monitoring of O-B statistics is crucial to detect and remove systematic errors coming from the measurements, the observation operator, and/or the NWP model. This work illustrates a 1-year O-B analysis for MWR observations in clear-sky conditions for an European-wide network of six MWRs. Observations include MWR brightness temperatures (TB) measured by the two most common types of MWR instruments. Background profiles are extracted from the French convective-scale model AROME-France before being converted into TB. The observation operator used to map atmospheric profiles into TB is the fast radiative transfer model RTTOV-gb. It is shown that O-B monitoring can effectively detect instrument malfunctions. O-B statistics (bias, standard deviation, and root mean square) for water vapour channels (22.24-30.0 GHz) are quite consistent for all the instrumental sites, decreasing from the 22.24 GHz line centre ( ˜ 2-2.5 K) towards the high-frequency wing ( ˜ 0.8-1.3 K). Statistics for zenith and lower-elevation observations show a similar trend, though values increase with increasing air mass. O-B statistics for temperature channels show different

  14. Inter-Calibration of Satellite Passive Microwave Land Observations from AMSR-E and AMSR2 Using Overlapping FY3B-MWRI Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Jinyang Du

    2014-09-01

    Full Text Available The development and continuity of consistent long-term data records from similar overlapping satellite observations is critical for global monitoring and environmental change assessments. We developed an empirical approach for inter-calibration of satellite microwave brightness temperature (Tb records over land from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E and Microwave Scanning Radiometer 2 (AMSR2 using overlapping Tb observations from the Microwave Radiation Imager (MWRI. Double Differencing (DD calculations revealed significant AMSR2 and MWRI biases relative to AMSR-E. Pixel-wise linear relationships were established from overlapping Tb records and used for calibrating MWRI and AMSR2 records to the AMSR-E baseline. The integrated multi-sensor Tb record was largely consistent over the major global vegetation and climate zones; sensor biases were generally well calibrated, though residual Tb differences inherent to different sensor configurations were still present. Daily surface air temperature estimates from the calibrated AMSR2 Tb inputs also showed favorable accuracy against independent measurements from 142 global weather stations (R2 ≥ 0.75, RMSE ≤ 3.64 °C, but with slightly lower accuracy than the AMSR-E baseline (R2 ≥ 0.78, RMSE ≤ 3.46 °C. The proposed method is promising for generating consistent, uninterrupted global land parameter records spanning the AMSR-E and continuing AMSR2 missions.

  15. Microwave-derived soil moisture over Mediterranean land uses: from ground-based radiometry to SMOS first observations

    Science.gov (United States)

    Saleh, Kauzar; Antolín, Carmen; Juglea, Silvia; Kerr, Yann; Millán-Scheiding, Cristina; Novello, Nathalie; Pardé, Mickael; Wigneron, Jean-Pierre; Zribi, Mehrez; López-Baeza, Ernesto

    2010-05-01

    plant growing cycle. 2) Airborne-based experiments. 2.1) ESA's SMOS Rehearsal 2008. For this campaign an area of 100 km2 of vineyards in winter-like conditions was flown on four days using the EMIRAD radiometer. Soil moisture could be retrieved with good accuracy but only after surface roughness was determined. In fact, the campaign highlighted that close to specular modelling of the surface reflectivity using 0-6 cm measurements of soil moisture underestimated the surface emission. This was observed also in other airborne data sets (Saleh et al. 2009). 2.2) CNES CAROLS campaigns. In 2009, the L-band CAROLS radiometer was flown on three occasions over an area of 1500 km2 covering vineyards, shrub land and Mediterranean pine forest. Main results of CAROLS 2009 will be presented in this communication, and the emphasis will be on comparing local to regional scale results given that CAROLS flights were performed at ~4000 m above the surface. For soil moisture, SVAT-derived, field soil moisture, and surface-type derived soil moisture will be used as ground truth. 3) SMOS data Finally, the results of the above mentioned experiments concerning L-MEB parameterisations will be the basis for comparisons between simulated brightness temperatures (TB) and measured TBs from SMOS at the VAS site. These exercises will be conducted in order to have an assessment of the L-MEB performance in a highly studied and monitored area, and to help pinpointing future areas of investigation in microwave radiometry. References Cano A., Saleh K., Wigneron J.P., Antolín C., Balling J., Kerr Y.H., Kruszewski A., Millán-Scheiding C., Søbjaerg S.S., Skou N., López-Baeza E. (2009), The SMOS Medierranean Ecosystem L-band experiment (MELBEX-I) over natural shrubs, Remote Sensing of Environment, in press. Saleh K., Kerr Y.H., Richaume P., Escorihuela, M.J., Panciera R., Delwart S., Walker J., Boulet G., Maisongrande P., Wursteisen P., Wigneron, J.P. (2009), Soil moisture retrievals at L-band using a two

  16. Evidence of Convective Redistribution of Carbon Monoxide in Aura Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) Observations

    Science.gov (United States)

    Manyin, Michael; Douglass, Anne; Schoeberl, Mark

    2010-01-01

    Vertical convective transport is a key element of the tropospheric circulation. Convection lofts air from the boundary layer into the free troposphere, allowing surface emissions to travel much further, and altering the rate of chemical processes such as ozone production. This study uses satellite observations to focus on the convective transport of CO from the boundary layer to the mid and upper troposphere. Our hypothesis is that strong convection associated with high rain rate regions leads to a correlation between mid level and upper level CO amounts. We first test this hypothesis using the Global Modeling Initiative (GMI) chemistry and transport model. We find the correlation is robust and increases as the precipitation rate (the strength of convection) increases. We next examine three years of CO profiles from the Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) instruments aboard EOS Aura. Rain rates are taken from the Tropical Rainfall Measuring Mission (TRMM) 3B-42 multi-satellite product. Again we find a correlation between mid-level and upper tropospheric CO, which increases with rain rate. Our result shows the critical importance of tropical convection in coupling vertical levels of the troposphere in the transport of trace gases. The effect is seen most clearly in strong convective regions such as the Inter-tropical Convergence Zone.

  17. Observing the Cosmic Microwave Background Polarization with Variable-delay Polarization Modulators for the Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Harrington, Kathleen; CLASS Collaboration

    2018-01-01

    The search for inflationary primordial gravitational waves and the optical depth to reionization, both through their imprint on the large angular scale correlations in the polarization of the cosmic microwave background (CMB), has created the need for high sensitivity measurements of polarization across large fractions of the sky at millimeter wavelengths. These measurements are subjected to instrumental and atmospheric 1/f noise, which has motivated the development of polarization modulators to facilitate the rejection of these large systematic effects.Variable-delay polarization modulators (VPMs) are used in the Cosmology Large Angular Scale Surveyor (CLASS) telescopes as the first element in the optical chain to rapidly modulate the incoming polarization. VPMs consist of a linearly polarizing wire grid in front of a moveable flat mirror; varying the distance between the grid and the mirror produces a changing phase shift between polarization states parallel and perpendicular to the grid which modulates Stokes U (linear polarization at 45°) and Stokes V (circular polarization). The reflective and scalable nature of the VPM enables its placement as the first optical element in a reflecting telescope. This simultaneously allows a lock-in style polarization measurement and the separation of sky polarization from any instrumental polarization farther along in the optical chain.The Q-Band CLASS VPM was the first VPM to begin observing the CMB full time in 2016. I will be presenting its design and characterization as well as demonstrating how modulating polarization significantly rejects atmospheric and instrumental long time scale noise.

  18. Calibration of passive remote observing optical and microwave instrumentation; Proceedings of the Meeting, Orlando, FL, Apr. 3-5, 1991

    Science.gov (United States)

    Guenther, Bruce W. (Editor)

    1991-01-01

    Various papers on the calibration of passive remote observing optical and microwave instrumentation are presented. Individual topics addressed include: on-board calibration device for a wide field-of-view instrument, calibration for the medium-resolution imaging spectrometer, cryogenic radiometers and intensity-stabilized lasers for EOS radiometric calibrations, radiometric stability of the Shuttle-borne solar backscatter ultraviolet spectrometer, ratioing radiometer for use with a solar diffuser, requirements of a solar diffuser and measurements of some candidate materials, reflectance stability analysis of Spectralon diffuse calibration panels, stray light effects on calibrations using a solar diffuser, radiometric calibration of SPOT 23 HRVs, surface and aerosol models for use in radiative transfer codes. Also addressed are: calibrated intercepts for solar radiometers used in remote sensor calibration, radiometric calibration of an airborne multispectral scanner, in-flight calibration of a helicopter-mounted Daedalus multispectral scanner, technique for improving the calibration of large-area sphere sources, remote colorimetry and its applications, spatial sampling errors for a satellite-borne scanning radiometer, calibration of EOS multispectral imaging sensors and solar irradiance variability.

  19. Short-term stratospheric ozone fluctuations observed by GROMOS microwave radiometer at Bern

    Science.gov (United States)

    Moreira, Lorena; Hocke, Klemens; Kämpfer, Niklaus

    2018-01-01

    The ground-based millimeter wave ozone spectrometer (GROMOS) has been continually measuring middle atmospheric ozone volume mixing ratio profiles above Bern, Switzerland (46.95°N, 7.44°E, 577 m), since 1994 in the frame of NDACC. The high temporal resolution of GROMOS (30 min) allows the analysis of short-term fluctuations. The present study analyses the temporal perturbations, ranging from 1 to 8 h, observed in stratospheric ozone from June 2011 to May 2012. The short-term fluctuations of stratospheric ozone are within 5%, and GROMOS appears to have relative amplitudes stable over time smaller than 2% at 10 hPa (32 km). The strongest natural fluctuations of stratospheric ozone (about 1% at 10 hPa) above Bern occur during winter due to displacements and deformations of the polar vortex towards mid-latitudes.[Figure not available: see fulltext.

  20. Analysis of a crossed Bragg cell acousto-optical spectrometer for SETI

    Science.gov (United States)

    Gulkis, Samuel

    The search for radio signals from extraterrestrial intelligent beings (SETI) requires the use of large instantaneous bandwidth (500 MHz) and high resolution (20 Hz) spectrometers. Digital systems with a high degree of modularity can be used to provide this capability, and this method has been widely discussed. Another technique for meeting the SETI requirement is to use a crossed Bragg cell spectrometer as described by Psaltis and Casasent. This technique makes use of the Folded Spectrum concept, introduced by Thomas. The Folded Spectrum is a 2-D Fourier Transform of a raster scanned 1-D signal. It is directly related to the long 1-D spectrum of the original signal and is ideally suited for optical signal processing. The folded spectrum technique has received little attention to date, primarily because early systems made use of photographic film which are unsuitable for the real time data analysis and voluminous data requirements of SETI. An analysis of the crossed Bragg cell spectrometer is presented as a method to achieve the spectral processing requirements for SETI. Systematic noise contributions unique to the Bragg cell system will be discussed.

  1. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  2. The influence of Vegetation Water Content (VWC) dynamics on microwave observations of a corn canopy during SMAPVEX16-IA

    Science.gov (United States)

    Steele-Dunne, Susan; Polo Bermejo, Jaime; Judge, Jasmeet; Bongiovanni, Tara; Chakrabarti, Subit; Liu, Pang-Wei; Bragdon, James; Hornbuckle, Brian

    2017-04-01

    Vegetation cover confounds soil moisture retrieval from both active and passive microwave remote sensing observations. Vegetation attenuates the signal from the soil as well as contributing to emission and scattering. The goal of this study was to characterize the vertical distribution of moisture within an agricultural canopy, to examine how this varies during the growing season and to determine the influence these changes have on emission and backscatter from the surface. To this end, an extensive campaign of destructive sampling was conducted in a rain-fed corn field at Buckeye, Iowa within the SMAPVEX16-IA study domain. The experiment duration extended from the beginning of IOP1 to the end of IOP2, i.e. from May 18 to August 16 2016. Destructive vegetation sampling was performed on most days upon which SMAP had both an ascending and a descending pass. On these days, destructive samples were collected at 6pm and 6pm unless the weather conditions were prohibitive. In addition to measuring the bulk vegetation water content for comparison to the SMAP retrieved VWC, the samples were split into leaves and stems. To study the vertical profiles, leaf moisture content was measured as a function of collar height and the stem was cut into 10cm sections. The influence of plant development on the bulk and profile VWC was clearly discernible in the observations. Diurnal variations in bulk VWC were relatively small due to moisture availability in the root zone. SMAP brightness temperatures, and tower-based observations from the University of Florida radiometer and radar systems were analyzed to investigate the impact of VWC variations on emission and backscatter. Dynamic variations in SMAP retrieved soil moisture were notably larger than those observed in-situ, particularly during the early growing season. This may be attributed to the difference between observed VWC and that used in the SMAP retrieval during the early growing season. Backscatter (and RVI) increased, as

  3. Diplomacy and the search for extraterrestrial intelligence (SETI)

    Science.gov (United States)

    Goodman, Allen E.

    Recent advances in astronomy indicate that the universe is spectacularly vast. Apparently, our Sun is like billions of other stars around which planets may circle; within just a thousand light years of Earth, for example, there are more than a million stars like the Sun. Within the Milky Way (only one of 100 billion observable galaxies) are an estimated 300-400 billion stars. Scientists now think that there are probably between 10 21 and 10 22 stars in the universe. With so many stars, it is highly probable that we are not alone. Just how likely extraterrestrial intelligence is or in how many places and varieties it will be found is impossible now to say. Serious scientists have constructed an equation to calculate the possibility, but the range of estimates of the number of other civilizations in the universe is so wide - anywhere from 200 million to less than 10 - and our understanding of astrophysics and cosmic evolution so primitive, that we could encounter extraterrestrials (ETs) well before it can be proved on paper that they have existed or could exist [1]. In fact, the capability to search for extraterrestrial intelligence will increase over the next five years at a rate and scale greater than at any time in human history. For example, a Harvard University observatory announced in October 1985 that it had linked a radio telescope to a new computerized multichannel spectrum analyzer and created a listening post (known as Project Meta) capable of simultaneously scanning up to 8.4 million radio channels. This development replaces a system whose capacity to search simultaneously and record radio signals was a mere 180,000 radio channels. The Hubble Space Telescope, when it is operational, will extend our present vision some seven times and possibly to the edge of the universe itself. If other planetary systems exist, this new instrument might locate them. And by the end of this decade, NASA will probably have begun a search for signals across the entire

  4. Long-term observations minus background monitoring of ground-based brightness temperatures from a microwave radiometer network

    Directory of Open Access Journals (Sweden)

    F. De Angelis

    2017-10-01

    Full Text Available Ground-based microwave radiometers (MWRs offer the capability to provide continuous, high-temporal-resolution observations of the atmospheric thermodynamic state in the planetary boundary layer (PBL with low maintenance. This makes MWR an ideal instrument to supplement radiosonde and satellite observations when initializing numerical weather prediction (NWP models through data assimilation. State-of-the-art data assimilation systems (e.g. variational schemes require an accurate representation of the differences between model (background and observations, which are then weighted by their respective errors to provide the best analysis of the true atmospheric state. In this perspective, one source of information is contained in the statistics of the differences between observations and their background counterparts (O–B. Monitoring of O–B statistics is crucial to detect and remove systematic errors coming from the measurements, the observation operator, and/or the NWP model. This work illustrates a 1-year O–B analysis for MWR observations in clear-sky conditions for an European-wide network of six MWRs. Observations include MWR brightness temperatures (TB measured by the two most common types of MWR instruments. Background profiles are extracted from the French convective-scale model AROME-France before being converted into TB. The observation operator used to map atmospheric profiles into TB is the fast radiative transfer model RTTOV-gb. It is shown that O–B monitoring can effectively detect instrument malfunctions. O–B statistics (bias, standard deviation, and root mean square for water vapour channels (22.24–30.0 GHz are quite consistent for all the instrumental sites, decreasing from the 22.24 GHz line centre ( ∼  2–2.5 K towards the high-frequency wing ( ∼  0.8–1.3 K. Statistics for zenith and lower-elevation observations show a similar trend, though values increase with increasing air mass. O

  5. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    Directory of Open Access Journals (Sweden)

    L. Moreira

    2016-08-01

    Full Text Available A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m. GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC. The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO, the quasi-biennial oscillation (QBO, the El Niño–Southern Oscillation (ENSO and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose

  6. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    Science.gov (United States)

    Moreira, Lorena; Hocke, Klemens; Navas-Guzmán, Francisco; Eckert, Ellen; von Clarmann, Thomas; Kämpfer, Niklaus

    2016-08-01

    A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is

  7. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  8. Life in the Universe - Astronomy and Planetary Science Research Experience for Undergraduates at the SETI Institute

    Science.gov (United States)

    Chiar, J.; Phillips, C. B.; Rudolph, A.; Bonaccorsi, R.; Tarter, J.; Harp, G.; Caldwell, D. A.; DeVore, E. K.

    2016-12-01

    The SETI Institute hosts an Astrobiology Research Experience for Undergraduates (REU) program. Beginning in 2013, we partnered with the Physics and Astronomy Dept. at Cal Poly Pomona, a Hispanic-serving university, to recruit underserved students. Over 11 years, we have served 155 students. We focus on Astrobiology since the Institute's mission is to explore, understand and explain the origin, nature and prevalence of life in the universe. Our REU students work with mentors at the Institute - a non-profit organization located in California's Silicon Valley-and at the nearby NASA Ames Research Center. Projects span research on survival of microbes under extreme conditions, planetary geology, astronomy, the Search for Extraterrestrial Intelligence (SETI), extrasolar planets and more. The REU program begins with an introductory lectures by Institute scientists covering the diverse astrobiology subfields. A week-long field trip to the SETI Institute's Allen Telescope Array (Hat Creek Radio Astronomy Observatory in Northern California) and field experiences at hydrothermal systems at nearby Lassen Volcanic National Park immerses students in radio astronomy and SETI, and extremophile environments that are research sites for astrobiologists. Field trips expose students to diverse environments and allow them to investigate planetary analogs as our scientists do. Students also participate in local trips to the California Academy of Sciences and other nearby locations of scientific interest, and attend the weekly scientific colloquium hosted by the SETI Institute at Microsoft, other seminars and lectures at SETI Institute and NASA Ames. The students meet and present at a weekly journal club where they hone their presentation skills, as well as share their research progress. At the end of the summer, the REU interns present their research projects at a session of the Institute's colloquium. As a final project, students prepare a 2-page formal abstract and 15-minute

  9. Surface and subsurface water from space : On the integration of microwave remote sensing observations with flood prediction systems

    NARCIS (Netherlands)

    Matgen, P.

    2011-01-01

    The technique of active microwave remote sensing has made much progress toward its high potential to monitor water storage changes in terrestrial surface and subsurface water bodies at various spatial and temporal scales. The number of studies demonstrating the support these data can offer in

  10. AMSR-E/Aqua Monthly Global Microwave Land Surface Emissivity

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a global land emissivity product using passive microwave observations from the Advanced Microwave Scanning Radiometer - Earth Observing System...

  11. Ground-based microwave weather radar observations and retrievals during the 2014 Holuhraun eruption (Bárðarbunga, Iceland)

    Science.gov (United States)

    Mereu, Luigi; Silvio Marzano, Frank; Barsotti, Sara; Montopoli, Mario; Yeo, Richard; Arngrimsson, Hermann; Björnsson, Halldór; Bonadonna, Costanza

    2015-04-01

    During an eruptive event the real-time forecasting of ash dispersal into the atmosphere is a key factor to prevent air traffic disasters. The ash plume is extremely hazardous to aircraft that inadvertently may fly through it. Real-time monitoring of such phenomena is crucial, particularly to obtain specific data for the initialization of eruption and dispersion models in terms of source parameters. The latter, such as plume height, ash concentration, mass flow rate and size spectra, are usually very difficult to measure or to estimate with a relatively good accuracy. Over the last years different techniques have been developed to improved ash plume detection and retrieval. Satellite-based observations, using multi-frequency visible and infrared radiometers, are usually exploited for monitoring and measuring dispersed ash clouds. The observations from geostationary orbit suffer from a relatively poor spatial resolution, whereas the low orbit level has a relatively poor temporal resolution. Moreover, the field-of-view of infrared radiometric measurements may be reduced by obstructions caused by water and ice clouds lying between the ground and the sensor's antenna. Weather radar-based observations represent an emerging technique to detect and, to a certain extent, mitigate the hazard from the ash plumes. Ground-based microwave scanning radar systems can provide the three-dimensional information about the detected ash volume with a fairly high spatial resolution every few minutes and in all weather conditions. Methodological studies have recently investigated the possibility of using single-polarization and dual-polarization ground-based radar for the remote sensing of volcanic ash cloud. In this respect, radar observations can be complementary to satellite observations. A microphysical electromagnetic characterization of volcanic ash was carried out in terms of dielectric properties, composition, size and orientation of ash particles. An extended Volcanic Ash Radar

  12. Analysis of a crossed Bragg-cell acousto optical spectrometer for SETI

    Science.gov (United States)

    Gulkis, S.

    1986-10-01

    The search for radio signals from extraterrestrial intelligent (SETI) beings requires the use of large instantaneous bandwidth (500 MHz) and high resolution (20 Hz) spectrometers. Digital systems with a high degree of modularity can be used to provide this capability, and this method has been widely discussed. Another technique for meeting the SETI requirement is to use a crossed Bragg-cell spectrometer as described by Psaltis and Casasent (1979). This technique makes use of the Folded Spectrum concept, introduced by Thomas (1966). The Folded Spectrum is a two-dimensional Fourier Transform of a raster scanned one-dimensional signal. It is directly related to the long one-dimensional spectrum of the original signal and is ideally suited for optical signal processing.

  13. Antarctic summer sea ice concentration and extent: comparison of ODEN 2006 ship observations, satellite passive microwave and NIC sea ice charts

    Science.gov (United States)

    Ozsoy-Cicek, B.; Xie, H.; Ackley, S. F.; Ye, K.

    2009-02-01

    Antarctic sea ice cover has shown a slight increase (NIC) ice edge and the AMSR-E (Advanced Microwave Scanning Radiometer-Earth Observing System) ice extent are examined, while the ASPeCt (Antarctic Sea Ice Process and Climate) ship observations from the Oden expedition in December 2006 are used as ground truth to verify the two products during Antarctic summer. While there is a general linear trend between ASPeCt and AMSR-E ice concentration estimates, there is poor correlation (R2=0.41) and AMSR-E tends to underestimate the low ice concentrations. We also found that the NIC sea ice edge agrees well with ship observations, while the AMSR-E shows the ice edge further south, consistent with its poorer detection of low ice concentrations. The northward extent of the ice edge at the time of observation (NIC) had mean values varying from 38 km to 102 km greater on different days for the area as compared with the AMSR-E sea ice extent. For the circumpolar area as a whole in the December period examined, AMSR-E therefore may underestimate the area inside the ice edge at this time by up to 14% or, 1.5 million km2 less area, compared to the NIC ice charts. Preliminary comparison of satellite scatterometer data however, suggests better resolution of low concentrations than passive microwave, and therefore better agreement with ship observations and NIC charts of the area inside the ice edge during Antarctic summer. A reanalysis data set for Antarctic sea ice extent that relies on the decade long scatterometer and high resolution satellite data set, instead of passive microwave, may therefore give better fidelity for the recent sea ice climatology.

  14. Responsibility, capability, and Active SETI: Policy, law, ethics, and communication with extraterrestrial intelligence

    Science.gov (United States)

    Vakoch, Douglas A.

    2011-02-01

    With recently growing interest in the Active Search for Extraterrestrial Intelligence (SETI), in which humankind would send intentional signals to extraterrestrial civilizations, there have been increased concerns about appropriate policy, as well as the role of space law and ethics in guiding such activities. Implicit in these discussions are notions of responsibility and capability that affect judgments about whether humans or other civilizations should initiate transmissions. Existing protocols that guide SETI research address transmissions from Earth, but there is debate over whether these guidelines should inform de novo transmissions as well. Relevant responsibilities to address include (1) looking out for the interests of humankind as a whole, (2) being truthful in interstellar messages, and (3) benefiting extraterrestrial civilizations. Our capabilities as a species and a civilization affect how well we can fulfill responsibilities, as seen when we consider whether we will be able to reach consensus about message contents (and whether that would be desirable), and whether we have the capacity to decode messages from beings that rely on different sensory modalities. The interplay of these responsibilities and capabilities suggests that humankind should place increased emphasis on Active SETI.

  15. Pešek lecture: SETI and society—decision trees

    Science.gov (United States)

    Billingham, John

    This paper presents a simplified decision tree diagram for SETI (the Search for Extraterrestrial Intelligence) and society. It deals with the series of steps and circumstances that follow from the quest for evidence of the existence of extraterrestrial civilizations, with the major goal of including those branch points which involve decisions that are societal rather than scientific or technological. Since SETI is based on science and technology these factors are also included in the decision diagram, but more in a summary fashion. A condensed list of the relevant societal disciplines is given. The most difficult decisions are those related to issues of transmitting communications from Earth to ETI. The diagram may be useful as a new way of looking at the subject of Communication with Extraterrestrial Intelligence (CETI), and how it inevitably blends into SETI. Arguments are made for vigorous pursuit of studies in all the societal, cultural and behavioral domains involved, and it is shown that many of these studies can profitably be undertaken now, before an ETI signal has been detected. Not least, it is argued that the newly emerging field of CETI and Society would benefit materially from the application of formal decision theory and analysis, and from game theory and utility theory.

  16. All Over the World: Mid-Twentieth Century Radio Astronomy and the Origin of the International SETI Network

    Science.gov (United States)

    Charbonneau, Rebecca

    2018-01-01

    Cold War mythology is rife with stories about secrecy, competition, espionage, and animosity. Yet the history behind the myth-- the overlooked scientists collaborating outside of the aims of the state-- also tells an interesting story. This paper examines the challenges of international scientific collaboration during the Cold War, focusing especially on a case study concerning Soviet radio astronomer Iosif Samuilovich Shklovskii and U.S. astrophysicist Carl Sagan, and their collaborative work on the search for extraterrestrial intelligence (SETI). Despite the hyper-politics that instigated and fueled the Space Race, SETI was held up as an ideal internationalist science, with the lofty goal of uniting all of humanity by situating it within a cosmic community. Although the internationalism of SETI discourse is not entirely unfounded due to its roots in international collaboration, further research indicates that such internationalism was in reality instilled with geopolitics, international conflict, and even espionage. That said, however, the cultural and philosophical perspectives of individual SETI scientists led them to operate within the tensions between national and ideological restraints and their own personal philosophical perspectives. In reviewing the letters of correspondence, conference proceedings, interviews, transcripts of lectures, and autobiographical writings of early-SETI radio astronomers, this paper ultimately argues that, although SETI was not the ideal internationalist science it was portrayed as, SETI pioneers were able to connect and form international networks within a contentious system which often centred on the restriction of free information and international collaboration through their mutual unconventional scientific interests, and facilitated by their personal utopian futurist philosophies.

  17. The Cosmic Microwave Background

    Science.gov (United States)

    Pierpaoli, E.

    2011-03-01

    In these lectures I present the physical aspects of the Cosmic Microwave Background primary and secondary anisotropies; the characteristics of the CMB power spectra and their dependence on cosmological parameters. I also discuss the observational status and future perspectives.

  18. Mapping UK snow accumulation using satellite passive microwave and visible-infrared remote sensing observations: two case studies from 2009 and 2010

    Science.gov (United States)

    Kelly, Richard

    2010-05-01

    In February 2009, an unusually significant snow storm deposited considerable amounts of snow in the UK for the first time in several years. A more persistent event deposited larger amounts of snow between December 2009 and January 2010; during this time snow cover duration exceeded a month in some locations and on 7 January, England Scotland and Wales were almost completely covered in snow as observed by NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). Such widespread snow cover has not been observed since 1963 and 1979. Information about snow quantity and distribution in the UK is sparse and while some official observations are made, most observations are made through community-based observers or via more esoteric online social networks. Furthermore, daily snow accumulation maps are not easily obtainable for the UK. Coupled with unusually cold temperatures which began in mid December, these case studies provide an excellent opportunity to re-evaluate the role of satellite passive microwave observations for estimating snow water equivalent in the UK. Satellite remote sensing observations were obtained for the two snow event periods. MODIS observations are used to determine the location of the snow when cloud does not obscure the field of view. Passive microwave observations from the Advanced Microwave Scanning Radiometer - EOS (AMSR-E) are used to estimate SWE. In the first instance, AMSR-E estimates from the standard NASA algorithm are tested. On account of the documented radio frequency interference at 10 GHz the estimates are deemed unsuitable. A re-configured algorithm is developed at the native sampling resolution (10 km in along and across track) projected to a UTM grid. The re-configured approach to estimate SWE uses 18, 23 36 and 89GHz channels (vertical and horizontal polarization) and uses a frequency ratio approach, rather than difference, to minimize the physical temperature effect on brightness temperatures at 18, 36 and 89 GHz. It also

  19. Meteorological Satellites (METSAT) and Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL)

    Science.gov (United States)

    1996-01-01

    This Failure Modes and Effects Analysis (FMEA) is for the Advanced Microwave Sounding Unit-A (AMSU-A) instruments that are being designed and manufactured for the Meteorological Satellites Project (METSAT) and the Earth Observing System (EOS) integrated programs. The FMEA analyzes the design of the METSAT and EOS instruments as they currently exist. This FMEA is intended to identify METSAT and EOS failure modes and their effect on spacecraft-instrument and instrument-component interfaces. The prime objective of this FMEA is to identify potential catastrophic and critical failures so that susceptibility to the failures and their effects can be eliminated from the METSAT/EOS instruments.

  20. Atmospheric absorption model for dry air and water vapor at microwave frequencies below 100 GHz derived from spaceborne radiometer observations

    Science.gov (United States)

    Wentz, Frank J.; Meissner, Thomas

    2016-05-01

    The Liebe and Rosenkranz atmospheric absorption models for dry air and water vapor below 100 GHz are refined based on an analysis of antenna temperature (TA) measurements taken by the Global Precipitation Measurement Microwave Imager (GMI) in the frequency range 10.7 to 89.0 GHz. The GMI TA measurements are compared to the TA predicted by a radiative transfer model (RTM), which incorporates both the atmospheric absorption model and a model for the emission and reflection from a rough-ocean surface. The inputs for the RTM are the geophysical retrievals of wind speed, columnar water vapor, and columnar cloud liquid water obtained from the satellite radiometer WindSat. The Liebe and Rosenkranz absorption models are adjusted to achieve consistency with the RTM. The vapor continuum is decreased by 3% to 10%, depending on vapor. To accomplish this, the foreign-broadening part is increased by 10%, and the self-broadening part is decreased by about 40% at the higher frequencies. In addition, the strength of the water vapor line is increased by 1%, and the shape of the line at low frequencies is modified. The dry air absorption is increased, with the increase being a maximum of 20% at the 89 GHz, the highest frequency considered here. The nonresonant oxygen absorption is increased by about 6%. In addition to the RTM comparisons, our results are supported by a comparison between columnar water vapor retrievals from 12 satellite microwave radiometers and GPS-retrieved water vapor values.

  1. Antarctic summer sea ice concentration and extent: comparison of ODEN 2006 ship observations, satellite passive microwave and NIC sea ice charts

    Directory of Open Access Journals (Sweden)

    B. Ozsoy-Cicek

    2009-02-01

    Full Text Available Antarctic sea ice cover has shown a slight increase (<1%/decade in overall observed ice extent as derived from satellite mapping from 1979 to 2008, contrary to the decline observed in the Arctic regions. Spatial and temporal variations of the Antarctic sea ice however remain a significant problem to monitor and understand, primarily due to the vastness and remoteness of the region. While satellite remote sensing has provided and has great future potential to monitor the variations and changes of sea ice, uncertainties remain unresolved. In this study, the National Ice Center (NIC ice edge and the AMSR-E (Advanced Microwave Scanning Radiometer-Earth Observing System ice extent are examined, while the ASPeCt (Antarctic Sea Ice Process and Climate ship observations from the Oden expedition in December 2006 are used as ground truth to verify the two products during Antarctic summer. While there is a general linear trend between ASPeCt and AMSR-E ice concentration estimates, there is poor correlation (R2=0.41 and AMSR-E tends to underestimate the low ice concentrations. We also found that the NIC sea ice edge agrees well with ship observations, while the AMSR-E shows the ice edge further south, consistent with its poorer detection of low ice concentrations. The northward extent of the ice edge at the time of observation (NIC had mean values varying from 38 km to 102 km greater on different days for the area as compared with the AMSR-E sea ice extent. For the circumpolar area as a whole in the December period examined, AMSR-E therefore may underestimate the area inside the ice edge at this time by up to 14% or, 1.5 million km2 less area, compared to the NIC ice charts. Preliminary comparison of satellite scatterometer data however, suggests better resolution of low concentrations than passive microwave, and therefore better agreement with ship observations and NIC charts of the area inside the ice edge during Antarctic

  2. The Search for Extraterrestrial Intelligence (SETI) and Whether to send 'Messages' (METI): A Case for Conversation, Patience and Due Diligence

    Science.gov (United States)

    Brin, D.

    Understanding the controversy over "Messages to Extra Terrestrial Intelligence" or METI requires a grounding in the history and rationale of SETI (Search for ETI). Insights since the turn of the century have changed SETI's scientific basis. Continued null results from the radio search do not invalidate continuing effort, but they do raise questions about long-held assumptions. Modified search strategies are discussed. The Great Silence or Fermi Paradox is appraised, along with the disruptive plausibility of interstellar travel. Psychological motivations for METI are considered. With this underpinning, we consider why a small cadre of SETI-ist radio astronomers have resisted the notion of international consultations before humanity takes a brash and irreversible step into METI, shouting our presence into the cosmos.

  3. Variations of mesoscale and large-scale sea ice morphology in the 1984 Marginal Ice Zone Experiment as observed by microwave remote sensing

    Science.gov (United States)

    Campbell, W. J.; Gloersen, P.; Josberger, E. G.; Johannessen, O. M.; Guest, P. S.; Mognard, N.; Shuchman, R.; Burns, B. A.; Lannelongue, N.; Davidson, K. L.

    1987-06-01

    During the summer 1984 Marginal Ice Zone Experiment in the Fram Strait and Greenland Sea (MIZEX '84), passive and active microwave sensors on five aircraft and the Nimbus 7 scanning multichannel microwave radiometer (SMMR) acquired synoptic sequential observations which when combined give a comprehensive sequential description of the mesoscale and large-scale ice morphology variations during the period June 9 through July 16, 1984. The high-resolution ice concentration distributions in these images agree well with the low-resolution SMMR distributions. For diffuse ice edges the 30% SMMR ice concentration isopleth corresponds to the ice edge, while for compact conditions the ice edge falls within the 40 to 50% SMMR isopleths. Throughout the experiment, ice edge meanders and eddies repeatedly formed, moved, and disappeared, but the ice edge remained within a 100-km-wide zone. The ice pack behind this alternately diffuse and compact edge underwent rapid and pronounced variations in ice concentration over a 200-km-wide zone. The aircraft microwave images show the complex structures and ephemeral nature of the mesoscale sea ice morphology. The difference in oceanographic forcing between the eastern and western sectors of the experiment area generated pronounced ice morphology differences. On the Yermak Plateau, from 3°E to 10°E, the weak ocean circulation allowed the wind to be the dominant force in determining the ice morphology. To the southwest of this region, over the Molloy Deep and the Greenland continental shelf break, from 3°E to 8°W, the ice morphology was dominated by the energetic East Greenland Current with its associated eddies and meanders.

  4. Microwave extraction of bioactive compounds

    Directory of Open Access Journals (Sweden)

    Monika Blekić

    2011-01-01

    Full Text Available Microwave extraction presents novel extraction and treatment method for food processing. In paper, several examples of microwave extraction of bioactive compounds are presented. Also, novel innovative equipment for microwave extraction and hydrodiffusion with gravitation is presented. Advantage of using novel equipment for microwave extraction is shown, and it include, shorter treatment time, less usage or without any solvent use. Novel method is compared to standard extraction methods. Some positive and negative aspects of microwave heating can be observed, and also its influence on development of oxidation in sunflower oil subjected to microwave heating. Also, use of microwaves for the extraction of essential oils is shown. One can also see the advantages of solvent-free microwave extraction of essential oil from aromatic herbs in comparison with the standard extraction, and determination of antioxidant components in rice bran oil extracted by microwave-assisted method. Comparison of microwave and ultrasound extraction, as well as positive and negative aspects of the combination of microwaves and ultrasound is described.

  5. CO at 40–80 km above Kiruna observed by the ground-based microwave radiometer KIMRA and simulated by the Whole Atmosphere Community Climate Model

    Directory of Open Access Journals (Sweden)

    C. G. Hoffmann

    2012-04-01

    Full Text Available This study compares CO in the Arctic stratosphere and mesosphere measured by ground-based microwave radiometry with simulations made with the Whole Atmosphere Community Climate Model driven with specified dynamical fields (SD-WACCM4 for the Arctic winters 2008/2009 and 2009/2010. CO is a tracer for polar winter middle atmosphere dynamics, hence the representation of polar dynamics in the model is examined indirectly. Measurements were taken with the KIruna Microwave RAdiometer (KIMRA. The instrument, which is located in Kiruna, Northern Sweden (67.8° N, 20.4° E, provides CO profiles between 40 and 80 km altitude.

    The present comparison, which is one of the first between SD-WACCM4 and measurements, is performed on the smallest space and time scales currently simulated by the model; the global model is evaluated daily at the particular model grid-point closest to Kiruna. As a guide to what can generally be expected from such a comparison, the same analysis is repeated for observations of CO from the Microwave Limb Sounder (MLS, a microwave radiometer onboard NASA's Aura satellite, which has global coverage. First, time-mean profiles of CO are compared, revealing that the profile shape of KIMRA deviates from SD-WACCM4 and MLS, especially in the upper mesosphere. SD-WACCM4 and MLS are mostly consistent throughout the range of altitude considered; however, SD-WACCM4 shows slightly lower values in the upper mesosphere. Second, the time evolution is compared for the complete time series, as well as for the slowly and rapidly evolving parts alone. Overall, the agreement among the datasets is very good and the model is almost as consistent with the measurements as the measurements are with each other. Mutual correlation coefficients of the slowly varying part of the CO time series are ≥0.9 over a wide altitude range. This demonstrates that the polar winter middle atmosphere dynamics is very well represented in SD-WACCM4 and that the

  6. Fermi paradox and alternative strategies for SETI programs - The anthropic principle and the search for close solar analogs

    Science.gov (United States)

    Fracassini, Massimo; Pasinetti Fracassini, Laura E.; Pasinetti, Antonio L.

    1988-07-01

    The Anthropic Principle, a new trend of modern cosmology, claims that the origin of life and the development of intelligent beings on the Earth is the result of highly selective biological processes, strictly tuned in the fundamental physical characteristics of the Universe. This principle could account for the failure of some programs of search for extraterrestrial intelligences (SETI) and suggests the search for strict solar analogs as a primary target for SETI strategies. In this connection, the authors have selected 22 solar analogs and discussed their choice.

  7. On the design of a postprocessor for a search for extraterrestrial intelligence /SETI/ system

    Science.gov (United States)

    Healy, T. J.; Seeger, C. L.; Stull, M. A.

    1979-01-01

    The design of an on-line postprocessor for a search for extraterrestrial intelligence (SETI) system is described. Signal processing tasks of the postprocessor include: (1) analysis of power level, phase coherence, and state of polarization of single-channel signals in a search for significant signals; (2) grouping or aggregation of adjacent channel data, time averaging of data; and (3) the detection of drifting and modulated signals. Control functions include multichannel spectrum analyzer frequency and clock control, system calibration and selfdiagnostic, control of data flow to and from short-term and long-term (archival) memories, and operation of detection subsystems, such as a visual display and a tunable receiver.

  8. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  9. Comparison of global observations and trends of total precipitable water derived from microwave radiometers and COSMIC radio occultation from 2006 to 2013

    Science.gov (United States)

    Ho, Shu-Peng; Peng, Liang; Mears, Carl; Anthes, Richard A.

    2018-01-01

    We compare atmospheric total precipitable water (TPW) derived from the SSM/I (Special Sensor Microwave Imager) and SSMIS (Special Sensor Microwave Imager/Sounder) radiometers and WindSat to collocated TPW estimates derived from COSMIC (Constellation System for Meteorology, Ionosphere, and Climate) radio occultation (RO) under clear and cloudy conditions over the oceans from June 2006 to December 2013. Results show that the mean microwave (MW) radiometer - COSMIC TPW differences range from 0.06 to 0.18 mm for clear skies, from 0.79 to 0.96 mm for cloudy skies, from 0.46 to 0.49 mm for cloudy but non-precipitating conditions, and from 1.64 to 1.88 mm for precipitating conditions. Because RO measurements are not significantly affected by clouds and precipitation, the biases mainly result from MW retrieval uncertainties under cloudy and precipitating conditions. All COSMIC and MW radiometers detect a positive TPW trend over these 8 years. The trend using all COSMIC observations collocated with MW pixels for this data set is 1.79 mm decade-1, with a 95 % confidence interval of (0.96, 2.63), which is in close agreement with the trend estimated by the collocated MW observations (1.78 mm decade-1 with a 95 % confidence interval of 0.94, 2.62). The sample of MW and RO pairs used in this study is highly biased toward middle latitudes (40-60° N and 40-65° S), and thus these trends are not representative of global average trends. However, they are representative of the latitudes of extratropical storm tracks and the trend values are approximately 4 to 6 times the global average trends, which are approximately 0.3 mm decade-1. In addition, the close agreement of these two trends from independent observations, which represent an increase in TPW in our data set of about 6.9 %, are a strong indication of the positive water vapor-temperature feedback on a warming planet in regions where precipitation from extratropical storms is already large.

  10. Comparison of global observations and trends of total precipitable water derived from microwave radiometers and COSMIC radio occultation from 2006 to 2013

    Directory of Open Access Journals (Sweden)

    S.-P. Ho

    2018-01-01

    Full Text Available We compare atmospheric total precipitable water (TPW derived from the SSM/I (Special Sensor Microwave Imager and SSMIS (Special Sensor Microwave Imager/Sounder radiometers and WindSat to collocated TPW estimates derived from COSMIC (Constellation System for Meteorology, Ionosphere, and Climate radio occultation (RO under clear and cloudy conditions over the oceans from June 2006 to December 2013. Results show that the mean microwave (MW radiometer – COSMIC TPW differences range from 0.06 to 0.18 mm for clear skies, from 0.79 to 0.96 mm for cloudy skies, from 0.46 to 0.49 mm for cloudy but non-precipitating conditions, and from 1.64 to 1.88 mm for precipitating conditions. Because RO measurements are not significantly affected by clouds and precipitation, the biases mainly result from MW retrieval uncertainties under cloudy and precipitating conditions. All COSMIC and MW radiometers detect a positive TPW trend over these 8 years. The trend using all COSMIC observations collocated with MW pixels for this data set is 1.79 mm decade−1, with a 95 % confidence interval of (0.96, 2.63, which is in close agreement with the trend estimated by the collocated MW observations (1.78 mm decade−1 with a 95 % confidence interval of 0.94, 2.62. The sample of MW and RO pairs used in this study is highly biased toward middle latitudes (40–60° N and 40–65° S, and thus these trends are not representative of global average trends. However, they are representative of the latitudes of extratropical storm tracks and the trend values are approximately 4 to 6 times the global average trends, which are approximately 0.3 mm decade−1. In addition, the close agreement of these two trends from independent observations, which represent an increase in TPW in our data set of about 6.9 %, are a strong indication of the positive water vapor–temperature feedback on a warming planet in regions where precipitation from extratropical

  11. Ice retreat in the Russian Arctic seas and assessment of the availability of the Northern Sea Route from satellite passive microwave observations

    Science.gov (United States)

    Shalina, E. V.

    2015-12-01

    This paper presents data on the sea ice area decline in the Northern Hemisphere and in the Russian Arctic seas, on the Northern Sea Route in particular, calculated from passive microwave satellite data. Observations show that the Arctic sea ice has reduced by an average of 5% per decade from November 1978 to the present day. It is noted that, since 2007, the highest sea ice area variability has been observed, which increases the uncertainty of the forecast of the ice coverage in the Arctic seas and thus increases risk for ships in ice-covered waters of northern seas. It is demonstrated that the decrease in summer sea ice area, observed at the end of the melt season, is much more intense than the total decrease in the Arctic sea ice area. On average it is 13% for September for the Arctic as a whole and from 24 to 40% per decade for the seas of the Russian Arctic. The study of changes in the ice conditions in the Northern Sea Route has been carried out for one of the optimal sailing routes. The results indicate a decrease in the ice concentration on the route in the summer months and almost complete route opening in September for the period from 2008 and 2012. It is shown that data from microwave radiometers can be used in the study of ice conditions in the Kara Gates and Vilkitsky Strait. The ice concentration reduction in both water channels is indicated. In the Kara Gates it is 15% and in the Vilkitsky Strait it is 9.5% per decade.

  12. Daily Area of Snow Melt Onset on Arctic Sea Ice from Passive Microwave Satellite Observations 1979–2012

    Directory of Open Access Journals (Sweden)

    Angela C. Bliss

    2014-11-01

    Full Text Available Variability in snow melt onset (MO on Arctic sea ice since 1979 is examined by determining the area of sea ice experiencing the onset of melting during the melt season on a daily basis. The daily MO area of the snow and ice surface is determined from passive microwave satellite-derived MO dates for the Arctic Ocean and sub-regions. Annual accumulations of MO area are determined by summing the time series of daily MO area through the melt season. Daily areas and annual accumulations of MO area highlight inter-annual and regional variability in the timing of MO area, which is sensitive to day-to-day variations in spring weather conditions. Two distinct spatial patterns in MO area accumulations including an intense, fast accumulating melt area pattern and a slow accumulating melt pattern are examined for two melting events in the Kara Sea. In comparing the 34 years of MO dates for the Arctic Ocean and sub-regions, melt accumulations have changed during the period. In the earlier years, 1979–1987, the MO generally was later in the year than the mean, while in more recent years, the MO accumulations have been occurring earlier in the melt season. The sub-regions of the Arctic Ocean also exhibit greater annual variability than the Arctic Ocean.

  13. Precipitation observation using microwave backhaul links in the alpine and pre-alpine region of Southern Germany

    Directory of Open Access Journals (Sweden)

    C. Chwala

    2012-08-01

    Full Text Available Measuring rain rates over complex terrain is afflicted with large uncertainties, because rain gauges are influenced by orography and weather radars are mostly not able to look into mountain valleys. We apply a new method to estimate near surface rain rates exploiting attenuation data from commercial microwave links in the alpine region of Southern Germany. Received signal level (RSL data are recorded minutely with small data loggers at the towers and then sent to a database server via GSM (Global System for Mobile Communications. Due to the large RSL fluctuations in periods without rain, the determination of attenuation caused by precipitation is not straightforward. To be able to continuously process the RSL data from July 2010 to October 2010, we introduce a new method to detect wet and dry periods using spectral time series analysis. Its performance and limitations are presented, showing that the mean detection error rates of wet and dry periods can be reduced to 10% for all five links. After, the wet/dry classification rain rates are derived from the RSL and compared to rain gauge and weather radar measurements. The resulting correlations differ for different links and reach values of R2 = 0.81 for the link-gauge comparison and R2 = 0.85 for the link-radar comparison.

  14. Precipitation observation using microwave backhaul links in the alpine and pre-alpine region of Southern Germany

    Science.gov (United States)

    Chwala, C.; Gmeiner, A.; Qiu, W.; Hipp, S.; Nienaber, D.; Siart, U.; Eibert, T.; Pohl, M.; Seltmann, J.; Fritz, J.; Kunstmann, H.

    2012-08-01

    Measuring rain rates over complex terrain is afflicted with large uncertainties, because rain gauges are influenced by orography and weather radars are mostly not able to look into mountain valleys. We apply a new method to estimate near surface rain rates exploiting attenuation data from commercial microwave links in the alpine region of Southern Germany. Received signal level (RSL) data are recorded minutely with small data loggers at the towers and then sent to a database server via GSM (Global System for Mobile Communications). Due to the large RSL fluctuations in periods without rain, the determination of attenuation caused by precipitation is not straightforward. To be able to continuously process the RSL data from July 2010 to October 2010, we introduce a new method to detect wet and dry periods using spectral time series analysis. Its performance and limitations are presented, showing that the mean detection error rates of wet and dry periods can be reduced to 10% for all five links. After, the wet/dry classification rain rates are derived from the RSL and compared to rain gauge and weather radar measurements. The resulting correlations differ for different links and reach values of R2 = 0.81 for the link-gauge comparison and R2 = 0.85 for the link-radar comparison.

  15. Microwave Irradiation

    Indian Academy of Sciences (India)

    The rapid heating of food in the kitchen using microwave ovens ... analysis; application to waste treatment; polymer technology; .... Microwave heating for carrying out reactions on solids has also attracted considerable attention in recent years. For such 'dry media' reactions, solid supports such as alumina, silica and.

  16. A language based on analogy to communicate cultural concepts in SETI

    Science.gov (United States)

    Musso, Paolo

    2011-02-01

    The present paper is a synthesis of three presentation given by myself at the Toulouse IAC 2001 ( Analogy as a tool to communicate abstract concepts in SETI), the Bremen IAC 2003 ( From maths to culture: towards an effective message), and the Vancouver IAC 2004 ( Philosophical and religious implications of extraterrestrial intelligent life). Its aim is to find a way to make our cultural concepts understandable to hypothetical extraterrestrials (ETs) in a SETI communication. First of all, I expose the reasons why I think that analogy could be a good tool for this purpose. Then, I try to show that this is possible only in the context of an integrated language, using both abstract symbols and pictures, also sketching two practical examples about some basic concepts of our moral and religious tradition. Further studies are required to determine whether this method could be extended to the higher-level abstract concepts in the other fields of our culture. Finally, I discuss the possible role of mathematics, logic and natural science in the construction of an analogy-based language for interstellar messages with a cultural content and a possible way of managing this matter from a social point of view.

  17. Astrobiology Research Experience for Undergraduates: An Interdisciplinary REU Program at the SETI Institute

    Science.gov (United States)

    Phillips, C. B.; Devore, E. K.

    2009-12-01

    The SETI Institute hosts a summer Astrobiology Research Experience for Undergraduates program for highly motivated students interested in astrobiology research. Students work with scientists at the SETI Institute and at the nearby NASA Ames Research Center on projects spanning the field of astrobiology from microbiology to planetary geology to astronomy and astrophysics. Each student is mentored by a scientist for his/her summer research project. As astrobiology is interdisciplinary, the first week includes a seminar series to provide a broad foundation in the field as the students begin their research projects. The 10-week program includes a week-long field trip to the SETI Institute’s Allen Telescope Array, located at the Hat Creek Radio Astronomy Observatory in Northern California, as well as a field experience at hydrothermal systems at nearby Lassen Volcanic National Park. Students also participate in local field trips to places like the California Academy of Sciences and other nearby locations of scientific interest, and attend seminars, lectures, and discussions on astrobiology. Students are also invited to attend events at nearby NASA Ames Research Center, which offers the opportunity to interact with other undergraduate and graduate students participating in NASA summer programs. At the end of the program, students write up and present their research projects, and mentors recommend some projects for submission to a national scientific conference, which the selected students will be funded to attend. The Astrobiology REU program emphasizes three main areas, which are listed in the table along with typical project themes. Each year, specific student research projects are described on the website, and students are asked to select the three that most interest them as a part of their applications. Applications are due in early February. Typically, 10 students apply for each available position. Students have been selected from colleges and universities

  18. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  19. Microwave Measurements

    CERN Document Server

    Skinner, A D

    2007-01-01

    The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses. The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measureme

  20. The Search for Cosmic Company: SETI on ngVLA

    Science.gov (United States)

    Croft, Steve; Siemion, Andrew; Hellbourg, Greg

    2018-01-01

    "Are we alone?" is one of the most profound human questions. The unprecedented capabilities of next generation radio telescopes, including ngVLA, will allow us to probe hitherto unexplored regions of parameter space, placing meaningful limits on the prevalence of technological civilizations in the Universe, or perhaps making one of the most significant discoveries in the history of science.Through both targeted and commensal observations, ngVLA data will be searched for signatures of technology (including narrow-band, Doppler-drifting, and more complex signals) that can be localized to particular positions on the sky. ngVLA provides critical capabilities in the 10 – 100 GHz range, a region of the spectrum used by many human technologies, to survey the sky at sensitivities unmatched by other facilities.

  1. AMSR-E/Aqua Monthly Global Microwave Land Surface Emissivity, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a global land emissivity product using passive microwave observations from the Advanced Microwave Scanning Radiometer - Earth Observing System...

  2. CORONAL MAGNETIC FIELDS DERIVED FROM SIMULTANEOUS MICROWAVE AND EUV OBSERVATIONS AND COMPARISON WITH THE POTENTIAL FIELD MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaki, Shun; Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Iwai, Kazumasa; Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Shiota, Daikou, E-mail: shunmi089@gmail.com [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2016-02-10

    We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA active region 11150, observed around 3:00 UT on 2011 February 3 using the Nobeyama Radioheliograph at 17 GHz. Because the thermal bremsstrahlung intensity at 17 GHz includes both chromospheric and coronal components, we extracted only the coronal component by measuring the coronal emission measure in EUV observations. In addition, we derived only the radio polarization component of the corona by selecting the region of coronal loops and weak magnetic field strength in the chromosphere along the line of sight. The upper limits of the coronal longitudinal magnetic fields were determined as 100–210 G. We also calculated the coronal longitudinal magnetic fields from the potential field extrapolation using the photospheric magnetic field obtained from the Helioseismic and Magnetic Imager. However, the calculated potential fields were certainly smaller than the observed coronal longitudinal magnetic field. This discrepancy between the potential and the observed magnetic field strengths can be explained consistently by two reasons: (1) the underestimation of the coronal emission measure resulting from the limitation of the temperature range of the EUV observations, and (2) the underestimation of the coronal magnetic field resulting from the potential field assumption.

  3. High time resolution observations of the polar stratosphere and mesosphere using a ground-based 230-250 GHz microwave radiometer

    Science.gov (United States)

    Newnham, D. A.; Espy, P. J.; Clilverd, M. A.; Maxfield, D. J.; Hartogh, P.; Holmén, K.; Blindheim, S.; Horne, R. B.

    2012-04-01

    Microwave radiometry is used to measure thermal emission by the Doppler- and pressure-broadened molecular rotational lines of atmospheric gases, from which vertical abundance profiles can be determined. Since solar radiation is not required for the measurement, the technique has the advantage that continuous observations are possible including throughout the polar winter. We describe the development of a passive microwave radiometer [Espy, P. J., P. Hartogh, and K. Holmen (2006), Proc. SPIE, 6362, 63620P, doi:10.1117/12.688953] for ground-based remote sensing of the polar middle atmosphere. The instrument measures nitric oxide (NO), ozone (O3), and carbon monoxide (CO) vertical profiles over the altitude range 35-90 km with time resolution as high as 15 minutes, allowing the diurnal variability of trace chemical species to be investigated. Heterodyne detection of atmospheric emission at 230 GHz and 250 GHz (wavelength ~1.25 mm) with a receiver noise temperature of 300 K is achieved using a superconductor-insulator-superconductor (SIS) mixer cooled to 4 K. The down-converted signals at 1.35 GHz and 2.10 GHz are analysed using both a moderate-resolution (28 kHz, 220 MHz bandwidth) and a high-resolution (14 kHz, 40 MHz bandwidth) chirp-transform spectrometer (CTS). The instrument was operated semi-autonomously at Troll station (72° 01'S 02° 32'E, 1270 m above sea level), Antarctica during 2008-10 and at the Arctic LIDAR Observatory for Middle Atmosphere Research (ALOMAR, 69° 16'N, 16° 00'E, 380 m above sea level), northern Norway during 2011-12. NO volume mixing ratio (VMR) profiles have been inverted from calibrated brightness temperature spectra of the NO line centred at 250.796 GHz, observed above Troll station, using the Microwave Observation Line Estimation and Retrieval (MOLIERE) version 5 code. A priori pressure, temperature, ozone, water vapour, and NO profiles above 30 km were calculated using the Sodankylä Ion and Neutral Chemistry (SIC, version 6

  4. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  5. A novel SETI strategy targeting the solar focal regions of the most nearby stars

    Science.gov (United States)

    Gillon, Michaël

    2014-02-01

    Many hypotheses have been raised to explain the famous Fermi paradox. One of them is that self-replicating probes could have explored the whole Galaxy, including our Solar System, and that they are still to be detected. In this scenario, it is proposed here that probes from neighboring stellar systems could use the stars they orbit as gravitational lenses to communicate efficiently with each other. Under this hypothesis, a novel SETI approach would be to monitor the solar focal regions of the most nearby stars to search for communication devices. The envisioned devices are probably not detectable by imagery or stellar occultation, but an intensive multi-spectral monitoring campaign could possibly detect some communication leakages. Another and more direct option would be to message the focal regions of nearby stars in an attempt to initiate a reaction.

  6. The relationship between NMDA receptors and microwave-induced learning and memory impairment: a long-term observation on Wistar rats.

    Science.gov (United States)

    Wang, Hui; Peng, Ruiyun; Zhao, Li; Wang, Shuiming; Gao, Yabing; Wang, Lifeng; Zuo, Hongyan; Dong, Ji; Xu, Xinping; Zhou, Hongmei; Su, Zhentao

    2015-03-01

    Abstract Purpose: To investigate whether high power microwave could cause continuous disorders to learning and memory in Wistar rats and to explore the underlying mechanisms. Eighty Wistar rats were exposed to a 2.856 GHz pulsed microwave source at a power density of 0 mW/cm(2) and 50 mW/cm(2) microwave for 6 min. The spatial memory ability, the structure of the hippocampus, contents of amino acids neurotransmitters in hippocampus and the expression of N-methyl-D-aspartic acid receptors (NMDAR) subunit 1, 2A and 2B (NR1, NR2A and NR2B) were detected at 1, 3, 6, 9, 12 and 18 months after microwave exposure. Our results showed that the microwave-exposed rats showed consistent deficiencies in spatial learning and memory. The level of amino acid neurotransmitters also decreased after microwave radiation. The ratio of glutamate (Glu) and gammaaminobutyric acid (GABA) significantly decreased at 6 months. Besides, the hippocampus showed varying degrees of degeneration of neurons, increased postsynaptic density and blurred synaptic clefts in the exposure group. The NR1 and NR2B expression showed a significant decrease, especially the NR2B expression. This study indicated that the content of amino acids neurotransmitters, the expression of NMDAR subunits and the variation of hippocampal structure might contribute to the long-term cognitive impairment after microwave exposure.

  7. Coronal extension of flaring region magnetic fields inferred from high-resolution microwave and type III burst observations

    Science.gov (United States)

    Lantos, P.; Pick, M.; Kundu, M. R.

    1984-01-01

    Observations of three solar radio bursts, obtained with the Very Large Array of the National Radio Astronomy Observatory at 6 cm wavelength, have been combined with meter observations from the Mark III Nancay Radioheliograph. There is a good correlation between solar activity observed at the two wavelength domains. A small change by about 10 sec in the centimetric burst location corresponds to a large change, by about 0.5 solar radius, in the related metric type III burst location. This indicates discrete injection/acceleration regions and the presence of very divergent magnetic fields. The bursts come from two distinct active regions. With two-dimensional spatial resolution, it is shown that, in this sample, each active region possesses a coronal extension that is separated from that of the neighboring active region.

  8. Enhanced short-term stratospheric ozone fluctuations observed by the GROMOS microwave radiometer during winter at Bern

    Science.gov (United States)

    Moreira, Lorena; Hocke, Klemens; Kämpfer, Niklaus

    2017-04-01

    The ground-based millimeter wave ozone spectrometer (GROMOS) has been continually measuring stratospheric and lower mesospheric ozone volume mixing ratio (VMR) profiles above Bern, Switzerland (46.95°N, 7.44°E, 577 m) since 1994. The high temporal resolution of GROMOS (30 minutes) allows the analysis of short-term fluctuations. The present study analyses the temporal perturbations, ranging from 1 to 4 hours, observed in stratospheric ozone from June 2011 to May 2012. We observe an increase in mid- and upper stratospheric ozone fluctuations of about 0.05 ppm or 0.9% from December to January. The strongest variations of stratospheric ozone above Bern are due to displacements of the polar vortex to mid-latitudes, related with sudden stratospheric warming (SSW) events and produced by breaking of planetary Rossby waves. The breaking of planetary waves and the disruptions of the polar vortex edge can also generate fluctuations in stratospheric ozone, for instance the so-called stratospheric streamers. The increase of inertia-gravity wave activity at the polar vortex edge during these SSW events can also be related with the short-term fluctuations observed in mid- and upper stratospheric ozone during winter.

  9. Observations of middle atmospheric H2O and O3 during the 2010 major sudden stratospheric warming by a network of microwave radiometers

    Directory of Open Access Journals (Sweden)

    N. Kämpfer

    2012-08-01

    Full Text Available In this study, we present middle atmospheric water vapor (H2O and ozone (O3 measurements obtained by ground-based microwave radiometers at three European locations in Bern (47° N, Onsala (57° N and Sodankylä (67° N during Northern winter 2009/2010. In January 2010, a major sudden stratospheric warming (SSW occurred in the Northern Hemisphere whose signatures are evident in the ground-based observations of H2O and O3. The observed anomalies in H2O and O3 are mostly explained by the relative location of the polar vortex with respect to the measurement locations. The SSW started on 26 January 2010 and was most pronounced by the end of January. The zonal mean temperature in the middle stratosphere (10 hPa increased by approximately 25 Kelvin within a few days. The stratospheric vortex weakened during the SSW and shifted towards Europe. In the mesosphere, the vortex broke down, which lead to large scale mixing of polar and midlatitudinal air. After the warming, the polar vortex in the stratosphere split into two weaker vortices and in the mesosphere, a new, pole-centered vortex formed with maximum wind speed of 70 m s−1 at approximately 40° N. The shift of the stratospheric vortex towards Europe was observed in Bern as an increase in stratospheric H2O and a decrease in O3. The breakdown of the mesospheric vortex during the SSW was observed at Onsala and Sodankylä as a sudden increase in mesospheric H2O. The following large-scale descent inside the newly formed mesospheric vortex was well captured by the H2O observations in Sodankylä. In order to combine the H2O observations from the three different locations, we applied the trajectory mapping technique on our H2O observations to derive synoptic scale maps of the H2O distribution. Based on our observations and the 3-D wind field, this method allows determining the approximate development of the stratospheric and mesospheric polar vortex and demonstrates the potential of a network of ground

  10. Cosmic microwave background, where next?

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Ground-based, balloon-borne and space-based experiments will observe the Cosmic Microwave Background in greater details to address open questions about the origin and the evolution of the Universe. In particular, detailed observations the polarization pattern of the Cosmic Microwave Background radiation have the potential to directly probe physics at the GUT scale and illuminate aspects of the physics of the very early Universe.

  11. Carbon cycling of European croplands: A framework for the assimilation of optical and microwave Earth observation data

    Science.gov (United States)

    Revill, Andrew; Sus, Oliver; Williams, Mathew

    2013-04-01

    Croplands are traditionally managed to maximise the production of food, feed, fibre and bioenergy. Advancements in agricultural technologies, together with land-use change, have approximately doubled World grain harvests over the past 50 years. Cropland ecosystems also play a significant role in the global carbon (C) cycle and, through changes to C storage in response to management activities, they can provide opportunities for climate change mitigation. However, quantifying and understanding the cropland C cycle is complex, due to variable environmental drivers, varied management practices and often highly heterogeneous landscapes. Efforts to upscale processes using simulation models must resolve these challenges. Here we show how data assimilation (DA) approaches can link C cycle modelling to Earth observation (EO) and reduce uncertainty in upscaling. We evaluate a framework for the assimilation of leaf area index (LAI) time series, empirically derived from EO optical and radar sensors, for state-updating a model of crop development and C fluxes. Sensors are selected with fine spatial resolutions (20-50 m) to resolve variability across field sizes typically used in European agriculture. Sequential DA is used to improve the canopy development simulation, which is validated by comparing time-series LAI and net ecosystem exchange (NEE) predictions to independent ground measurements and eddy covariance observations at multiple European cereal crop sites. Significant empirical relationships were established between the LAI ground measurements and the optical reflectance and radar backscatter, which allowed for single LAI calibrations being valid for all the cropland sites for each sensor. The DA of all EO LAI estimates results indicated clear adjustments in LAI and an enhanced representation of daily CO2 exchanges, particularly around the time of peak C uptake. Compared to the simulation without DA, the assimilation of all EO LAI estimates improved the predicted at

  12. Cumulative-Phase-Alteration of Galactic-Light Passing Through the Cosmic-Microwave-Background: A New Mechanism for Some Observed Spectral-Shifts

    Directory of Open Access Journals (Sweden)

    Tank H. K.

    2012-07-01

    Full Text Available Currently, whole of the measured “cosmological-red-shift ” is interpreted as due to the “metric-expansion-of-space”; so for the required “closer -density” of the universe, we need twenty times more mass-energy than the visible baryonic-matter contained in the universe. This paper proposes a new mechanism, which can account for good per- centage of the red-shift in the extra-galactic-light, greatly reducing the requirement of dark matter-energy. Also, this mechanism can cause a new kin d of blue-shift reported here, and their observational evidences. These spectral-s hifts are proposed to result due to cumulative phase-alteration of extra-galactic-light b ecause of vector-addition of: (i electric-field of extra-galactic-light and (ii that of the cosmic-microwave-background (CMB. Since the center-frequency of CMB is much lower than extra-galactic-light, the cumulative-phase-alteration results in red -shift, observed as an additional contribu- tor to the measured “cosmological red-shift”; and since the center-frequency of CMB is higher than the radio-frequency-signals used to measure velocity of space-probes like: Pioneer-10, Pioneer-11, Galileo and Ulysses, the cum ulative-phase-alteration re- sulted in blue-shift, leading to the interpretation of deceleration of these space-probes. While the galactic-light experiences the red-shift, and th e ranging-signals of the space- probes experience blue -shift, they are comparable in magnitude, providing a supportive- evidence for the new mechanism proposed here. More confirmative-experiments for this new mechanism are also proposed.

  13. Are We Alone? GAVRT Search for Extra Terrestrial Intelligence (SETI) Project

    Science.gov (United States)

    Bensel, Holly; Cool, Ian; St. Mary's High School Astronomy Club; St. Mary's Middle School Astronomy Club

    2017-01-01

    The Goldstone Apple Valley Radio Telescope Program (GAVRT) is a partnership between NASA’s Jet Propulsion Laboratory and the Lewis Center for Educational Research. The program is an authentic science investigation program for students in grades K through 12 and offers them the ability to learn how to be a part of a science team while they are making a real contribution to scientific knowledge.Using the internet from their classroom, students take control of a 34-meter decommissioned NASA radio telescope located at the Goldstone Deep Space Network complex in California. Students collect data on strong radio sources and work in collaboration with professional radio astronomers to analyze the data.Throughout history man has wondered if we were alone in the Universe. SETI - or the Search for Extra Terrestrial Intelligence - is one of the programs offered through GAVRT that is designed to help answer that question. By participating in SETI, students learn about science by doing real science and maybe, if they get very lucky, they might make the most important discovery of our lifetime: Intelligent life beyond Earth!At St. Mary’s School, students in grades 6-12 have participated in the project since its inception. The St. Mary’s Middle School Astronomy Club is leading the way in their relentless search for ET and radio telescope studies. Students use the radio telescope to select a very small portion of the Milky Way Galaxy - or galactic plane - and scan across it over and over in the hopes of finding a signal that is not coming from humans or radio interference. The possibility of being the first to discover an alien signal has kept some students searching for the past three years. For them to discover something of this magnitude is like winning the lottery: small chance of winning - big payoff. To that end, the club is focusing on several portions of the Milky Way where they have detected a strong candidate in the past. The hope is to pick it up a second and

  14. An ensemble Kalman filter dual assimilation of thermal infrared and microwave satellite observations of soil moisture into the Noah land surface model

    Science.gov (United States)

    Hain, Christopher R.; Crow, Wade T.; Anderson, Martha C.; Mecikalski, John R.

    2012-11-01

    Studies that have assimilated remotely sensed soil moisture (SM) into land surface models (LSMs) have generally focused on retrievals from microwave (MW) sensors. However, retrievals from thermal infrared (TIR) sensors have also been shown to add unique information, especially where MW sensors are not able to provide accurate retrievals (due to, e.g., dense vegetation). In this study, we examine the assimilation of a TIR product based on surface evaporative flux estimates from the Atmosphere Land Exchange Inverse (ALEXI) model and the MW-based VU Amsterdam NASA surface SM product generated with the Land Parameter Retrieval Model (LPRM). A set of data assimilation experiments using an ensemble Kalman filter are performed over the contiguous United States to assess the impact of assimilating ALEXI and LPRM SM retrievals in isolation and together in a dual-assimilation case. The relative skill of each assimilation case is assessed through a data denial approach where a LSM is forced with an inferior precipitation data set. The ability of each assimilation case to correct for precipitation errors is quantified by comparing with a simulation forced with a higher-quality precipitation data set. All three assimilation cases (ALEXI, LPRM, and Dual assimilation) show relative improvements versus the open loop (i.e., reduced RMSD) for surface and root zone SM. In the surface zone, the dual assimilation case provides the largest improvements, followed by the LPRM case. However, the ALEXI case performs best in the root zone. Results from the data denial experiment are supported by comparisons between assimilation results and ground-based SM observations from the Soil Climate Analysis Network.

  15. Re-Excavation of Seti First Tomb, Kv17, Luxor, Egypt

    Directory of Open Access Journals (Sweden)

    Ayman HAMED

    2013-12-01

    Full Text Available This article is discussing technical challenges within engineering works made during re-excavation of the 174 m long tunnel which was cut into bedrock of desert shale known as 'Esna shale'. Recent historical events, during the last decade, explained much of the tunnel deformations and dirt filling inside tunnel space "Debris", caused by multiple water runoff attack to king's valley. The author is also discussing the challenging work under severe financial regime; using non conventional solutions adopted with extraordinary actions in using junk yard equipment. Seti I tomb, is considered as the deepest opening in the valley, not mentioning the risk in re-excavation the tomb, harsh atmospheric conditions inside the tunnel, measured and monitored by author, needed a serious ventilation system to serve workers during removal of dirt. Through that, an interesting mathematical relation between atmospheric variables has been emphasized. Design of steel supporting system serving an inclined deep tunnel with irregular circumference, under strict condition of reversibility, has been performed as a remarkable topic, to solve and apply in such archaeological site. Finally, the article is considered as a scientific pattern for application of geo-engineering in conservation of underground archaeological sites.

  16. Microwave Filters

    OpenAIRE

    Zhou, Jiafeng

    2010-01-01

    The general theory of microwave filter design based on lumped-element circuit is described in this chapter. The lowpass prototype filters with Butterworth, Chebyshev and quasielliptic characteristics are synthesized, and the prototype filters are then transformed to bandpass filters by lowpass to bandpass frequency mapping. By using immitance inverters ( J - or K -inverters), the bandpass filters can be realized by the same type of resonators. One design example is given to verify the theory ...

  17. Cosmic Microwave Background Anisotropies

    OpenAIRE

    Hu, Wayne; Dodelson,Scott

    2001-01-01

    Cosmic microwave background (CMB) temperature anisotropies have and will continue to revolutionize our understanding of cosmology. The recent discovery of the previously predicted acoustic peaks in the power spectrum has established a working cosmological model: a critical density universe consisting of mainly dark matter and dark energy, which formed its structure through gravitational instability from quantum fluctuations during an inflationary epoch. Future observations should test this mo...

  18. Advances in microwaves 8

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 8 covers the developments in the study of microwaves. The book discusses the circuit forms for microwave integrated circuits; the analysis of microstrip transmission lines; and the use of lumped elements in microwave integrated circuits. The text also describes the microwave properties of ferrimagnetic materials, as well as their interaction with electromagnetic waves propagating in bounded waveguiding structures. The integration techniques useful at high frequencies; material technology for microwave integrated circuits; specific requirements on technology for d

  19. A comparative study on microwave and routine tissue processing

    Directory of Open Access Journals (Sweden)

    T Mahesh Babu

    2011-01-01

    Conclusions: The individual scores by different observers regarding the various parameters included in the study were statistically insignificant, the overall quality of microwave-processed and microwave-stained slides appeared slightly better than conventionally processed and stained slides.

  20. Analysis of mixing-layer height retrieval methods using backscatter lidar returns and microwave-radiometer temperature observations in the context of synergy

    Science.gov (United States)

    Saeed, Umar; Rocadenbosch, Francesc

    2017-04-01

    Mixing Layer Height (MLH) is an important parameter in many different atmospheric and meteorological applications. However, there does not exist a single instrument or method which provides accurate and physically consistent estimates of MLH. Instead, there are several methods for MLH estimation based on the measurements of different atmospheric tracers using different instruments [1, 2]. In this work, MLH retrieval methods using backscattered lidar signals and Microwave Radiometer (MWR)-retrieved potential-temperature profiles are compared in terms of their associated uncertainties. The Extended Kalman Filter (EKF) is used for MLH retrieval from backscattered lidar signals [3] and parcel method [4] is used for MLH retrieval from MWR-retrieved potential-temperature profiles. Measurement and retrieval errors are revisited and incorporated into the MLH estimation methods used. Uncertainties on MLH estimates from the two methods are compared along with a combined MLH-retrieval discussion case. The uncertainty analysis is validated using long-term lidar and MWR measurement data, under different atmospheric conditions, from the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany [5]. MLH estimates from a Doppler wind lidar and radiosondes are used as reference. This work has received funding from the European Union Seventh Framework Programme, FP7 People, ITN Marie Curie Actions Programme (2012-2016) in the frame of ITaRS project (GA 289923), H2020 programme under ACTRIS-2 project (GA 654109), the Spanish Ministry of Economy and Competitiveness - European Regional Development Funds under TEC2015-63832-P project, and from the Generalitat de Catalunya (Grup de Recerca Consolidat) 2014-SGR-583. [1] S. Emeis, Surface-based Remote Sensing of the Atmospheric Boundary Layer. 978-90-481-9339-4, Springer, 2010. [2] P. Seibert, F. Beyrich, S.-E. Gryning, S. Joffre, A. Rasmussen, and P. Tercier, "Review and intercomparison of operational methods for the

  1. The transcension hypothesis: Sufficiently advanced civilizations invariably leave our universe, and implications for METI and SETI

    Science.gov (United States)

    Smart, John M.

    2012-09-01

    civilizations, but constrained transcension should be by far the norm for all mature civilizations. The transcension hypothesis has significant and testable implications for our current and future METI and SETI agendas. If all universal intelligence eventually transcends to black-hole-like environments, after which some form of merger and selection occurs, and if two-way messaging (a send-receive cycle) is severely limited by the great distances between neighboring and rapidly transcending civilizations, then sending one-way METI or probes prior to transcension becomes the only real communication option. But one-way messaging or probes may provably reduce the evolutionary diversity in all civilizations receiving the message, as they would then arrive at their local transcensions in a much more homogenous fashion. If true, an ethical injunction against one-way messaging or probes might emerge in the morality and sustainability systems of all sufficiently advanced civilizations, an argument known as the Zoo hypothesis in Fermi paradox literature, if all higher intelligences are subject to an evolutionary attractor to maximize their local diversity, and a developmental attractor to merge and advance universal intelligence. In any such environment, the evolutionary value of sending any interstellar message or probe may simply not be worth the cost, if transcension is an inevitable, accelerative, and testable developmental process, one that eventually will be discovered and quantitatively described by future physics. Fortunately, transcension processes may be measurable today even without good physical theory, and radio and optical SETI may each provide empirical tests. If transcension is a universal developmental constraint, then without exception all early and low-power electromagnetic leakage signals (radar, radio, television), and later, optical evidence of the exoplanets and their atmospheres should reliably cease as each civilization enters its own technological singularities

  2. Inter-Calibration of Passive Microwave Satellite Brightness Temperatures Observed by F13 SSM/I and F17 SSMIS for the Retrieval of Snow Depth on Arctic First-Year Sea Ice

    Directory of Open Access Journals (Sweden)

    Qingquan Liu

    2017-12-01

    Full Text Available Passive microwave satellite brightness temperatures (TB that were observed by the F13 Special Sensor Microwave/Imager (SSM/I and the subsequent F17 Special Sensor Microwave Imager/Sounder (SSMIS were inter-calibrated using empirical relationship models during their overlap period. Snow depth (SD on the Arctic first-year sea ice was further retrieved. The SDs derived from F17 TB and F13C TB which were calibrated F17 TB using F13 TB as the baseline were then compared and evaluated against in situ SD measurements based on the Operational IceBridge (OIB airborne observations from 2009 to 2013. Results show that Cavalieri inter-calibration models (CA models perform smaller root mean square error (RMSE than Dai inter-calibration models (DA models, and the standard deviation of OIB SDs in the 25 km pixels is around 6 cm on first-year sea ice. Moreover, the SDs derived from the calibrated F17 TB using F13 TB as the baseline were in better agreement than the F17 SDs as compared with OIB SDs, with the biases of −2 cm (RMSE of 5 cm and −9 cm (RMSE of 10 cm, respectively. We conclude that TB observations from F17 SSMIS calibrated to F13 SSM/I as the baseline should be recommended when performing the sensors’ biases correction for SD purpose based on the existing algorithm. These findings could serve as a reference for generating more consistent and reliable TB, which could help to improve the retrieval and analysis of long-term snow depth on the Arctic first-year sea ice.

  3. Microwave susceptibility experiments

    Energy Technology Data Exchange (ETDEWEB)

    McConaghy, C.

    1984-05-29

    In certain experimental environments, systems can be affected or damaged by microwave pulses. I have conducted tests at LLNL to understand the phenomenology of microwave susceptibility of system components and subsystem components. To date, my experiments have concentrated on bipolar transistors, similar to what might be used in discrete analog circuits, and on CMOS RAM chips, which might be used in a computer memory system. I observed a decrease in failure energies for both the transistor and the integrated curcuit as I shortened the microwave pulse width. An S band (2.86 GHz) transmit/receive (T/R) tube has also been tested both at S band and at X band (8.16 GHz). The S band pulse had limitations in rise-time from zero power, which had an effect on the amount of power that could be transmitted through the T/R tube, as much as 0.7% of the incident power passed through the tube. All tests were conducted in closed-waveguide or coax test-fixtures, in contrast to the anechoic chambers utilized by other experimenters. I have used both S band and X band Klystron generators. For very high power (greater than 1 MW), I used an additional pulse-compression cavity at S band. Other subsystem components such as an X band mixer and an X band T/R tube will be tested in the future. 8 references.

  4. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  5. A Microwave Plasma Closing Switch

    Science.gov (United States)

    Lock Kang, Weng; Rader, Mark; Alexeff, Igor

    1996-11-01

    A microwave plasma closing switch has been constructed using a fluorescent lamp as the central conductor of a coaxial line. When the lamp is energized, the coaxial line transmits microwaves. When the lamp is de-energized, the plasma conductor disappears, and the system reverts to a waveguide beyond cutoff. We have observed up to 61 dB difference in transmission between energized and de-energized operation. A simple model of the line using capacitors, inductors and resistors using the resistance measured in the tube predicts the observed behavior very successfully.

  6. Inter-comparison and evaluation of sea ice algorithms: towards further identification of challenges and optimal approach using passive microwave observations

    DEFF Research Database (Denmark)

    Ivanova, N.; Pedersen, L. T.; Tonboe, R. T.

    2015-01-01

    to retrieve sea ice concentration globally for climate monitoring purposes. This approach consists of a combination of two algorithms plus dynamic tie points implementation and atmospheric correction of input brightness temperatures. The method minimizes inter-sensor calibration discrepancies and sensitivity......Sea ice concentration has been retrieved in polar regions with satellite microwave radiometers for over 30 years. However, the question remains as to what is an optimal sea ice concentration retrieval method for climate monitoring. This paper presents some of the key results of an extensive...... algorithm inter-comparison and evaluation experiment. The skills of 30 sea ice algorithms were evaluated systematically over low and high sea ice concentrations. Evaluation criteria included standard deviation relative to independent validation data, performance in the presence of thin ice and melt ponds...

  7. Variability of winter-time middle atmospheric water vapour over the Arctic as observed with a ground-based microwave radiometer

    Science.gov (United States)

    Tschanz, Brigitte; Kivi, Rigel; Rüfenacht, Rolf; Kämpfer, Niklaus

    2014-05-01

    Middle atmospheric water vapour has a long chemical lifetime and can therefore be used as a tracer for dynamics. The ground-based microwave radiometer MIAWARA-C is designed for the use on campaigns and measures profiles of water vapour in the upper stratosphere and mesosphere and thus provides valuable data for the investigation of atmospheric processes. It has been operational for five years and has successfully participated in measurement campaigns under various climatic conditions in Germany, Switzerland, California, Finland and on la Réunion. The temporal resolution of the obtained water vapour profiles approximately 2 hours depending on tropospheric conditions. During two campaigns from January to June 2010 and from July 2011 to April 2013 in Sodankylä, Finland, MIAWARA-C monitored time series of polar middle atmospheric water vapour for three winters with three Sudden Stratospheric Warmings (SSW) occurring in early 2010, 2012 and 2013. The obtained time series are used to study the effects of the three SSWs on middle-atmospheric water vapour. During an SSW, humid mid- to low-latitude air is transported towards the polar region resulting in a fast increase in water vapour. The descent of water vapour after the SSW allows the estimation of the descent rate over the polar region as the normal wintertime circulation reforms. Results from the three SSWs are compared. The ground-based water vapour data is combined with sonde data of the Finnish Meteorological Institute and ground-based microwave wind measurements for one winter in order to obtain a more complete picture of the dynamics in the polar winter atmosphere.

  8. Behaviors of young children around microwave ovens.

    Science.gov (United States)

    Robinson, Marla R; O'Connor, Annemarie; Wallace, Lindsay; Connell, Kristen; Tucker, Katherine; Strickland, Joseph; Taylor, Jennifer; Quinlan, Kyran P; Gottlieb, Lawrence J

    2011-11-01

    Scald burn injuries are the leading cause of burn-related emergency room visits and hospitalizations for young children. A portion of these injuries occur when children are removing items from microwave ovens. This study assessed the ability of typically developing children aged 15 months to 5 years to operate, open, and remove the contents from a microwave oven. The Denver Developmental Screening Test II was administered to confirm typical development of the 40 subjects recruited. All children recruited and enrolled in this study showed no developmental delays in any domain in the Denver Developmental Screening Test II. Children were observed for the ability to open both a push and pull microwave oven door, to start the microwave oven, and to remove a cup from the microwave oven. All children aged 4 years were able to open the microwaves, turn on the microwave, and remove the contents. Of the children aged 3 years, 87.5% were able to perform all study tasks. For children aged 2 years, 90% were able to open both microwaves, turn on the microwave, and remove the contents. In this study, children as young as 17 months could start a microwave oven, open the door, and remove the contents putting them at significant risk for scald burn injury. Prevention efforts to improve supervision and caregiver education have not lead to a significant reduction in scald injuries in young children. A redesign of microwave ovens might prevent young children from being able to open them thereby reducing risk of scald injury by this mechanism.

  9. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between...

  10. Advances in microwaves 7

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 7 covers the developments in the study of microwaves. The book discusses the effect of surface roughness on the propagation of the TEM mode, as well as the voltage breakdown of microwave antennas. The text also describes the theory and design considerations of single slotted-waveguide linear arrays and the techniques and theories that led to the achievement of wide bandwidths and ultralow noise temperatures for communication applications. The book will prove invaluable to microwave engineers.

  11. Remote measurement of microwave distribution based on optical detection

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Zhong; Ding, Wenzheng; Yang, Sihua; Chen, Qun, E-mail: redrocks-chenqun@hotmail.com, E-mail: xingda@scnu.edu.cn; Xing, Da, E-mail: redrocks-chenqun@hotmail.com, E-mail: xingda@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China)

    2016-01-04

    In this letter, we present the development of a remote microwave measurement system. This method employs an arc discharge lamp that serves as an energy converter from microwave to visible light, which can propagate without transmission medium. Observed with a charge coupled device, quantitative microwave power distribution can be achieved when the operators and electronic instruments are in a distance from the high power region in order to reduce the potential risk. We perform the experiments using pulsed microwaves, and the results show that the system response is dependent on the microwave intensity over a certain range. Most importantly, the microwave distribution can be monitored in real time by optical observation of the response of a one-dimensional lamp array. The characteristics of low cost, a wide detection bandwidth, remote measurement, and room temperature operation make the system a preferred detector for microwave applications.

  12. Observation

    Science.gov (United States)

    Kripalani, Lakshmi A.

    2016-01-01

    The adult who is inexperienced in the art of observation may, even with the best intentions, react to a child's behavior in a way that hinders instead of helping the child's development. Kripalani outlines the need for training and practice in observation in order to "understand the needs of the children and...to understand how to remove…

  13. Nonlinearities in Microwave Superconductivity

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2012-01-01

    The research is focused on the modeling of nonlinear properties of High Temperature Superconducting (HTS) thin films, using Bardeen, Cooper, Schrieffer and Lumped Element Circuit theories, with purpose to enhance microwave power handling capabilities of microwave filters and optimize design of microwave circuits in micro- and nano- electronics.

  14. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  15. [Eye heating caused by microwave ovens].

    Science.gov (United States)

    Leitgeb, N; Tropper, K

    1993-01-01

    To clarify the question as to whether microwave ovens represent a risk for the eyes, a worst-case situation was investigated in which it was assumed that a child observes the internal heating process with its eyes as close to the door of a microwave oven as it is possible to get. As expected, heating of the eyes was observed, which, however, was caused mainly by the conventional heating process rather than by microwave radiation. Significant microwave heating was observed only when increased scattered radiation was simulated by inactivating the safety contacts and opening the door of the microwave oven. When the door is opened to a clearly visible gap width (2.3 cm), the contribution of the microwave component to the overall temperature increase of 5 degrees C after one hour of continuous exposure did not exceed 16%. Even at the maximum possible door gap width which just did not cause the oven to switch off automatically (2.6 cm), 15 minutes of continuous exposure contributed only 50% to the 2 degrees C temperature increase. On the basis of these results, damage to the eye through the use of microwave ovens can be excluded.

  16. Mikrodenetleyici Denetimli Televizyon Deney Seti Tasarımı ve Gerçekleştirilmesi

    Directory of Open Access Journals (Sweden)

    Serdar ÇİÇEK

    2009-03-01

    Full Text Available Bu çalışmada, teknik ve mesleki eğitim veren fakülteler, yüksekokullar, endüstri meslek liseleri, çıraklık ve yaygın eğitim merkezleri, meslek kursu veren belediyeler ve özel eğitim merkezleri vb. kurumlardaki görüntü sistemleri, televizyon tekniği, televizyon teknik servisliği gibi televizyon sisteminin ve televizyon arıza-onarım-bakım konularının işlendiği derslerde, derslerin pratik uygulama kısmında kullanılmak üzere bir televizyon deney seti tasarlanmış ve gerçekleştirilmiştir. Bu deney seti ile öğrenciler/ kursiyerler derste edindiği teorik bilgiler ışığında televizyon sistemlerini daha iyi kavrayabilecek, televizyon arızalarını bulma becerisini uygulamalı olarak geliştirebilecektir. Deney setine ek olarak televizyon ile bağlantılı bir ölçüm panosu da gerçekleştirilmiştir. Böylece televizyon üzerinde istenen ölçümler rahatça yapılabilmektedir. Geliştirilen deney setinde, kullanıcının birden fazla hatayı aynı anda gerçekleştirerek hata bulma adımlarını geliştirmesi mümkündür.

  17. Heat sink effect on tumor ablation characteristics as observed in monopolar radiofrequency, bipolar radiofrequency, and microwave, using ex vivo calf liver model.

    Science.gov (United States)

    Pillai, Krishna; Akhter, Javid; Chua, Terence C; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L

    2015-03-01

    Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.

  18. Medical applications of microwaves

    Science.gov (United States)

    Vrba, Jan; Lapes, M.

    2004-04-01

    Medical applications of microwaves (i.e. a possibility to use microwave energy and/or microwave technique and technology for therapeutical purposes) are a quite new and a very rapidly developing field. Microwave thermotherapy is being used in medicine for the cancer treatment and treatment of some other diseases since early eighties. In this contribution we would like to offer general overview of present activities in the Czech Republic, i.e. clinical applications and results, technical aspects of thermo therapeutic equipment and last but not least, prospective diagnostics based on microwave principals ant technology and instrumentation.

  19. The windows of SETI--frequency and time in the search for extraterrestrial intelligence.

    Science.gov (United States)

    Oliver, B M

    1987-01-01

    On Earth intelligent life evolved as a natural consequence of the events set in motion when the planet formed over 4 billion years ago. Since chemical evolution and solar-system formation appear to be occurring throughout the universe, we theorize that our universe may be rich with planets populated by intelligent beings who, like us, can search for evidence of other technological civilizations. Terrestrial civilization now has this capability. But if we do not begin the search soon, we'll lose the opportunity to do it from Earth as interfering signals of Earthly origin rapidly close the microwave window.

  20. High brightness microwave lamp

    Science.gov (United States)

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  1. Observational Research on Star and Planetary System Formation

    Science.gov (United States)

    Simpson, Janet P.

    1998-01-01

    Institute scientists collaborate with a number of NASA Ames scientists on observational studies of star and planetary system formation to their mutual benefit. As part of this collaboration, SETI scientists have, from 1988 to the present: (1) contributed to the technical studies at NASA Ames of the Stratospheric Observatory for Infrared Astronomy (SOFIA), an infrared 2.5 meter telescope in a Boeing 747, which will replace the Kuiper Airborne Observatory (KAO), a 0.9 meter telescope in a Lockheed C-141. SOFIA will be an important facility for the future exploration of the formation of stars and planetary systems, and the origins of life, and as such will be an important future facility to SETI scientists; (2) worked with the Laboratory Astrophysics Group at Ames, carrying out laboratory studies of the spectroscopic properties of ices and pre-biotic organics, which could be formed in the interstellar or interplanetary media; (3) helped develop a photometric approach for determining the Frequency of Earth-Sized Inner Planets (FRESIP) around solar-like stars, a project (now called Kepler) which complements the current efforts of the SETI Institute to find evidence for extraterrestrial intelligence; and (4) carried out independent observational research, in particular research on the formation of stars and planetary systems using both ground-based telescopes as well as the KAO.

  2. Weather influence on passive microwave brightness temperatures

    OpenAIRE

    Løvås, Stig M.; Rubinstein, Irene; Ulstad, Christian

    1994-01-01

    Sea ice charts produced using spacebornc passive microwave observations are used on routine basis at several ice forecasting centres and during sea ice research campaigns. The capability of passive microwave sensors to monitor the earth, regardless of cloud cover or daylight, and the 1400 km swath width (SSM/I) make these sensors well suited not only for ice forecasting but also for providing information needed for planning northern oceanic routes. The retrieval of sea ice parameters is carri...

  3. Using your microwave oven. Lesson 6, Microwave oven management

    OpenAIRE

    Woodard, Janice Emelie, 1929-

    1984-01-01

    Discusses cooking and reheating foods in microwave ovens, and adapting conventional recipes for the microwave. Revised Includes the publication: Adapting conventional recipes to microwave cooking : fact sheet 84 by Janice Woodard, Rebecca Lovingood, R.H. Trice.

  4. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  5. Microwave and RF engineering

    CERN Document Server

    Sorrentino, Roberto

    2010-01-01

    An essential text for both students and professionals, combining detailed theory with clear practical guidance This outstanding book explores a large spectrum of topics within microwave and radio frequency (RF) engineering, encompassing electromagnetic theory, microwave circuits and components. It provides thorough descriptions of the most common microwave test instruments and advises on semiconductor device modelling. With examples taken from the authors' own experience, this book also covers:network and signal theory;electronic technology with guided electromagnetic pr

  6. The study for the incipient solvation process of NaCl in water: the observation of the NaCl-(H2O)n (n = 1, 2, and 3) complexes using Fourier-transform microwave spectroscopy.

    Science.gov (United States)

    Mizoguchi, Asao; Ohshima, Yasuhiro; Endo, Yasuki

    2011-08-14

    Pure rotational spectra of the sodium chloride-water complexes, NaCl-(H(2)O)(n) (n = 1, 2, and 3), in the vibronic ground state have been observed by a Fourier- transform microwave spectrometer coupled with a laser ablation source. The (37)Cl-isotopic species and a few deuterated species have also been observed. From the analyses of the spectra, the rotational constants, the centrifugal distortion constants, and the nuclear quadrupole coupling constants of the Na and Cl nuclei were determined precisely for all the species. The molecular structures of NaCl-(H(2)O)(n) were determined using the rotational constants and the molecular symmetry. The charge distributions around Na and Cl nuclei in NaCl are dramatically changed by the complex formation with H(2)O. Prominent dependences of the bond lengths r(Na-Cl) on the number of H(2)O were also observed. By a comparison with results of theoretical studies, it is shown that the structure of NaCl-(H(2)O)(3) is approaching to that of the contact ion-pair, which is considered to be an intermediate species in the incipient solvation process.

  7. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymeric materials. The variable frequency microwave furnace, whose initial conception and design was funded by the AIM Materials Program, allows the authors, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of various thermoset resins will be studied because it holds the potential of in-situ curing of continuous-fiber composites for strong, lightweight components or in-situ curing of adhesives, including metal-to-metal. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  8. Advances in microwaves 3

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 3 covers the advances and applications of microwave signal transmission and Gunn devices. This volume contains six chapters and begins with descriptions of ground-station antennas for space communications. The succeeding chapters deal with beam waveguides, which offer interesting possibilities for transmitting microwave energy, as well as with parallel or tubular beams from antenna apertures. A chapter discusses the electron transfer mechanism and the velocity-field characteristics, with a particular emphasis on the microwave properties of Gunn oscillators. The l

  9. On-Chip Microwave Quantum Hall Circulator

    Directory of Open Access Journals (Sweden)

    A. C. Mahoney

    2017-01-01

    Full Text Available Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, “slow-light” response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330  μm diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  10. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A

  11. Microwave hydrology: A trilogy

    Science.gov (United States)

    Stacey, J. M.; Johnston, E. J.; Girard, M. A.; Regusters, H. A.

    1985-01-01

    Microwave hydrology, as the term in construed in this trilogy, deals with the investigation of important hydrological features on the Earth's surface as they are remotely, and passively, sensed by orbiting microwave receivers. Microwave wavelengths penetrate clouds, foliage, ground cover, and soil, in varying degrees, and reveal the occurrence of standing liquid water on and beneath the surface. The manifestation of liquid water appearing on or near the surface is reported by a microwave receiver as a signal with a low flux level, or, equivalently, a cold temperature. Actually, the surface of the liquid water reflects the low flux level from the cosmic background into the input terminals of the receiver. This trilogy describes and shows by microwave flux images: the hydrological features that sustain Lake Baykal as an extraordinary freshwater resource; manifestations of subsurface water in Iran; and the major water features of the Congo Basin, a rain forest.

  12. Microwave and millimeter wave astrochemistry: Laboratory studies of transition metal-containing free radicals and spectroscopic observations of molecular interstellar environments

    Science.gov (United States)

    Adande, Gilles Rapotchombo

    Progress in our understanding of the chemical composition of the interstellar medium leans both on laboratory analyses of high resolution rotational spectra from molecules that may be present in these regions, and on radio astronomical observations of molecular tracers to constrain astrochemical models. Due to the thermodynamic conditions in outer space, some molecules likely to be found in interstellar regions in relevant abundances are open shell radicals. In a series of laboratory studies, the pure rotational spectra of the transition metal containing radicals sulfur species ScS, YS, VS and ZnSH were obtained for the first time. In addition to accurate and precise rest frequencies for these species, bonding characteristics were determined from fine and hyperfine molecular parameters. It was found that these sulfides have a higher degree of covalent bonding than their mostly ionic oxide counterparts. Isomers and isotope ratios are excellent diagnostic tools for a variety of astrochemical models. From radio observations of isotopes of nitrile species, the galactic gradient of 14N/15N was accurately established. A further study of this ratio in carbon rich asymptotic giant branch stars provided observational evidence for an unknown process in J type carbon stars, and highlighted the need to update stellar nucleosynthesis models. Proper radiative transfer modeling of the emission spectra of interstellar molecules can yield a wealth of information about the abundance and distribution of these species within the observed sources. To model the asymmetric emission of SO and SO2 in oxygen-rich supergiants, an in-house code was developed, and successfully applied to gain insight into circumstellar sulfur chemistry of VY Canis Majoris. It was concluded that current astrochemistry kinetic models, based on spherical symmetry assumptions, need to be revisited.

  13. The Microwave Radiative Properties of Falling Snow Derived from Nonspherical Ice Particle Models. Part II: Initial Testing Using Radar, Radiometer and In Situ Observations

    Science.gov (United States)

    Olson, William S.; Tian, Lin; Grecu, Mircea; Kuo, Kwo-Sen; Johnson, Benjamin; Heymsfield, Andrew J.; Bansemer, Aaron; Heymsfield, Gerald M.; Wang, James R.; Meneghini, Robert

    2016-01-01

    In this study, two different particle models describing the structure and electromagnetic properties of snow are developed and evaluated for potential use in satellite combined radar-radiometer precipitation estimation algorithms. In the first model, snow particles are assumed to be homogeneous ice-air spheres with single-scattering properties derived from Mie theory. In the second model, snow particles are created by simulating the self-collection of pristine ice crystals into aggregate particles of different sizes, using different numbers and habits of the collected component crystals. Single-scattering properties of the resulting nonspherical snow particles are determined using the discrete dipole approximation. The size-distribution-integrated scattering properties of the spherical and nonspherical snow particles are incorporated into a dual-wavelength radar profiling algorithm that is applied to 14- and 34-GHz observations of stratiform precipitation from the ER-2 aircraft-borne High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar. The retrieved ice precipitation profiles are then input to a forward radiative transfer calculation in an attempt to simulate coincident radiance observations from the Conical Scanning Millimeter-Wave Imaging Radiometer (CoSMIR). Much greater consistency between the simulated and observed CoSMIR radiances is obtained using estimated profiles that are based upon the nonspherical crystal/aggregate snow particle model. Despite this greater consistency, there remain some discrepancies between the higher moments of the HIWRAP-retrieved precipitation size distributions and in situ distributions derived from microphysics probe observations obtained from Citation aircraft underflights of the ER-2. These discrepancies can only be eliminated if a subset of lower-density crystal/aggregate snow particles is assumed in the radar algorithm and in the interpretation of the in situ data.

  14. GHRSST Level 2P Gridded Global Subskin Sea Surface Temperature from the Advanced Scanning Microwave Radiometer - Earth Observing System (AMSR-E) on the NASA Aqua Satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Advanced Microwave Scanning Radiometer (AMSR-E) was launched on 4 May 2002, aboard NASA's Aqua spacecraft. The National Space Development Agency of Japan (NASDA)...

  15. GHRSST Level 2P Global Subskin Sea Surface Temperature from the Advanced Scanning Microwave Radiometer - Earth Observing System (AMSR-E) on the NASA Aqua Satellite (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Advanced Microwave Scanning Radiometer (AMSR-E) was launched on 4 May 2002, aboard NASA's Aqua spacecraft. The National Space Development Agency of Japan (NASDA)...

  16. GHRSST Level 2P Regional Subskin Sea Surface Temperature from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) on the NASA Aqua satellite for the Atlantic Ocean (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Advanced Microwave Scanning Radiometer (AMSR-E) was launched on 4 May 2002, aboard NASA's Aqua spacecraft. The National Space Development Agency of Japan (NASDA)...

  17. Microwave SQUID multiplexer demonstration for cosmic microwave background imagers

    Science.gov (United States)

    Dober, B.; Becker, D. T.; Bennett, D. A.; Bryan, S. A.; Duff, S. M.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Hubmayr, J.; Mates, J. A. B.; Reintsema, C. D.; Vale, L. R.; Ullom, J. N.

    2017-12-01

    Key performance characteristics are demonstrated for the microwave superconducting quantum interference device (SQUID) multiplexer (μmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the μmux produces a white, input referred current noise level of 29 pA/ √{H z } at a microwave probe tone power of -77 dB, which is well below the expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure 98 pA/ √{H z } in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e., phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ˜100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the μmux as a viable readout technique for future CMB imaging instruments.

  18. Relative Timing of Microwave and HXR Bursts

    Science.gov (United States)

    Bastian, T. S.; Aschwanden, M. J.

    1997-05-01

    The close correlation between microwave and hard X-ray (HXR) emission during flares has often been cited as evidence that the same population of energetic electrons is responsible for both types of emission. The two emissions differ in detail, however. Imaging observations have demonstrated that the two are not necessarily cospatial and timing observations have demonstrated that the microwaves are often significantly delayed with respect to HXR emission, typically by several seconds, but occassionally by much longer times. Such delays are in seeming conflict with the thick target model for HXR emission in its simplest form, and with the idea that microwave and HXR emissions result from essentially the same population of electrons. One way to reconcile the delay between microwaves and HXRs in the thick target model is to suppose that that electron trapping is significant (e.g., Cornell et al., ApJ, 279, 875). For a magnetic trap containing a plasma of constant density, high energy electrons have a longer lifetime against collisions than low energy electrons (tau_ {def} ~ E(3/2) ). Hence the energetic electrons responsible for the microwaves remain in the trap longer and the microwave emission they emit peaks later than the HXR emission. Another possibility is that higher energy electrons are accelerated later than lower energy electrons (so-called ``second-step'' acceleration models; e.g., Bai and Dennis 1985, ApJ, 292, 699). To explore the question in detail we have assembled a sample of 16 flares observed simultaneously in microwaves by the Nobeyama radioheliograph and in HXRs by the BATSE instrument on board the CGRO in burst trigger mode. The former imaged the flares at 17 GHz with an angular resolution of ~ 10'' and a time resolution of either 50 msec or 1 sec. The latter obtained medium energy resolution spectra (16 channels) between 20-200 keV with a time resolution of 16 or 64 msec. We present preliminary results of our analysis.

  19. Intersunspot Microwave Sources

    Science.gov (United States)

    Bakunina, I. A.; Melnikov, V. F.; Solov'ev, A. A.; Abramov-Maximov, V. E.

    2015-01-01

    We studied a number of solar active regions using two-dimensional spatially resolved microwave observations. Data from the Nobeyama Radioheliograph and the Siberian Solar Radio Telescope together with observations by the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO) have allowed us to identify long-lived intersunspot sources (ISSs) in most of the investigated active regions. Their centers are often located above the line-of-sight magnetic field inversion line that separates the leading and following polarities of a full active region (first type of ISS) or above the inversion line that separates magnetic polarities inside of a complex of sunspots (second type of ISS). ISSs of the first type are extended and, in general, they are sources of bremsstrahlung emission. ISSs of the second type are compact and are, most likely, sources of gyroresonance or gyrosynchrotron emission. We propose a qualitative model involving three types of magnetic connectivity to explain how long-lasting ISSs may be generated.

  20. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  1. Moisture Retrievals from the Windsat spaceborne polarimetric microwave radiometer

    NARCIS (Netherlands)

    Parinussa, R.M.; Holmes, T.R.H.; de Jeu, R.A.M.

    2012-01-01

    An existing methodology to derive surface soil moisture from passive microwave satellite observations is applied to the WindSat multifrequency polarimetric microwave radiometer. The methodology is a radiative-transfer-based model that has successfully been applied to a series of (historical)

  2. Advances in microwaves 4

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 4 covers some innovations in the devices and applications of microwaves. This volume contains three chapters and begins with a discussion of the application of microwave phasers and time delay elements as beam steering elements in array radars. The next chapter provides first an overview of the technical aspects and different types of millimeter waveguides, followed by a survey of their application to railroads. The last chapter examines the general mode of conversion properties of nonuniform waveguides, such as waveguide tapers, using converted Maxwell's equatio

  3. Microwave coupler and method

    Science.gov (United States)

    Holcombe, C. E.

    1984-11-01

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  4. Advances in microwaves

    CERN Document Server

    Young, Leo

    1967-01-01

    Advances in Microwaves, Volume 2 focuses on the developments in microwave solid-state devices and circuits. This volume contains six chapters that also describe the design and applications of diplexers and multiplexers. The first chapter deals with the parameters of the tunnel diode, oscillators, amplifiers and frequency converter, followed by a simple physical description and the basic operating principles of the solid state devices currently capable of generating coherent microwave power, including transistors, harmonic generators, and tunnel, avalanche transit time, and diodes. The next ch

  5. Emitron: microwave diode

    Science.gov (United States)

    Craig, G.D.; Pettibone, J.S.; Drobot, A.T.

    1982-05-06

    The invention comprises a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves by utilizing the interaction of electromagnetic waves with electron flow in diodes not requiring an external magnetic field. Anode and cathode surfaces are electrically charged with respect to one another by electron flow, for example caused by a Marx bank voltage source or by other charged particle flow, for example by a high energy charged particle beam. This produces an electric field which stimulates an emitted electron beam to flow in the anode-cathode region. The emitted electrons are accelerated by the electric field and coherent microwaves are produced by the three dimensional spatial and temporal interaction of the accelerated electrons with geometrically allowed microwave modes which results in the bunching of the electrons and the pumping of at least one dominant microwave mode.

  6. Microwave Service Towers

    Data.gov (United States)

    Department of Homeland Security — This file is an extract of the Universal Licensing System (ULS) licensed by the Wireless Telecommunications Bureau (WTB). It consists of Microwave Transmitters (see...

  7. Microwave system engineering principles

    CERN Document Server

    Raff, Samuel J

    1977-01-01

    Microwave System Engineering Principles focuses on the calculus, differential equations, and transforms of microwave systems. This book discusses the basic nature and principles that can be derived from thermal noise; statistical concepts and binomial distribution; incoherent signal processing; basic properties of antennas; and beam widths and useful approximations. The fundamentals of propagation; LaPlace's Equation and Transmission Line (TEM) waves; interfaces between homogeneous media; modulation, bandwidth, and noise; and communications satellites are also deliberated in this text. This bo

  8. Microwave Processing of Materials

    Science.gov (United States)

    1994-01-01

    reactions in sol-gel processing, gas-phase synthesis , solution evaporation/decomposition, or hydrothermal reactions. Each of these, and other powder... synthesis methods, will be described next. Sol-Gel Decomposition/Drying Microwaves have been used in several of the processing stages to synthesize BaTiO3 ...high surface areas (10-700 m2/g). Hydrothermal Reactions Microwave- hydrothermal processing has been utilized in catalyzing the synthesis of crystalline

  9. A microwave powered sensor assembly for microwave ovens

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a microwave powered sensor assembly for micro- wave ovens. The microwave powered sensor assembly comprises a microwave antenna for generating an RF antenna signal in response to microwave radiation at a predetermined excitation frequency. A dc power supply circuit...... in a microwave oven chamber....... of the microwave powered sensor assembly is operatively coupled to the RF antenna signal for extracting energy from the RF antenna signal and produce a power supply voltage. A sensor is connected to the power supply voltage and configured to measure a physical or chemical property of a food item under heating...

  10. Microwave remote sensing laboratory design

    Science.gov (United States)

    Friedman, E.

    1979-01-01

    Application of active and passive microwave remote sensing to the study of ocean pollution is discussed. Previous research efforts, both in the field and in the laboratory were surveyed to derive guidance for the design of a laboratory program of research. The essential issues include: choice of radar or radiometry as the observational technique; choice of laboratory or field as the research site; choice of operating frequency; tank sizes and material; techniques for wave generation and appropriate wavelength spectrum; methods for controlling and disposing of pollutants used in the research; and pollutants other than oil which could or should be studied.

  11. The Tomb of SETI i (KV17) in the Florence Egyptian Museum. Integrated Non-Invasive Methods for Documentation, Material History and Diagnostics

    Science.gov (United States)

    Coppola, M.; Bracci, S.; Cantisani, E.; Magrini, D.

    2017-05-01

    The tomb of Seti I (KV17) is a magnificent example of New Kingdom funerary architecture, among the longest tombs in the Valley of the Kings. As part of a collaboration between the Egyptian Museum in Florence, the University of Florence and CNR, a survey project was launched, with non-invasive methods, on the fragments from the Seti I tomb, in Florence, coming from a gate jamb connecting the chamber F to the corridor G, taken by the franco-tuscan expedition in 1829. The primary goal is to achieve the best level of documentation, knowledge of the material history and conservation assessment. Preliminary results allowed to focus some steps of the history of this fragment, from its realization to the present. The digital documentation created an excellent support for the mapping and management of the collected information. Even if still on a preliminary phase, this study shows how the combination of imaging and spectroscopic techniques allowed the characterization of many materials and the mapping of their distribution on the surface. Several original pigments have been identified as well as many anomalies due to subsequent interventions.

  12. Microwave remote sensing of ionized air.

    Energy Technology Data Exchange (ETDEWEB)

    Liao, S.; Gopalsami, N.; Heifetz, A.; Elmer, T.; Fiflis, P.; Koehl, E. R.; Chien, H. T.; Raptis, A. C. (Nuclear Engineering Division)

    2011-07-01

    We present observations of microwave scattering from ambient room air ionized with a negative ion generator. The frequency dependence of the radar cross section of ionized air was measured from 26.5 to 40 GHz (Ka-band) in a bistatic mode with an Agilent PNA-X series (model N5245A) vector network analyzer. A detailed calibration scheme is provided to minimize the effect of the stray background field and system frequency response on the target reflection. The feasibility of detecting the microwave reflection from ionized air portends many potential applications such as remote sensing of atmospheric ionization and remote detection of radioactive ionization of air.

  13. The microwave spectrum of methane sulphonyl chloride

    NARCIS (Netherlands)

    Eijck, B.P. van; Korthof, A.J.; Mijlhoff, F.C.

    The microwave spectrum of SO2ClCH3 was observed by means of Stark modulation and double resonance modulation. Rotational constants, centrifugal distortion parameters and nuclear quadrupole coupling constants are reported for the 35Cl and 37Cl species. An unambiguous choice between three possible

  14. Microwave properties of vanadium borate glasses

    Indian Academy of Sciences (India)

    Unknown

    The maximum loss was found to be at 15V2O5 mol%. The peak was observed in loss with tempera- ture. Keywords. Semiconducting glass; V2O5–B2O3; microwave properties. 1. Introduction. Ceramics and glasses possessing high relative dielectric constant, ε′ (~ 20 ~ 90), high quality factor, Q (> 3000–. 35000 at 3 GHz), ...

  15. Controlling Josephson dynamics by strong microwave fields

    NARCIS (Netherlands)

    Chesca, B.; Savel'ev, E.; Rakhmanov, A.L.; Smilde, H.J.H.; Hilgenkamp, Johannes W.M.

    2008-01-01

    We observe several sharp changes in the slope of the current-voltage characteristics (CVCs) of thin-film ramp-edge Josephson junctions between YBa2Cu3O7−delta and Nb when applying strong microwave fields. Such behavior indicates an intriguing Josephson dynamics associated with the switching from a

  16. Microwave brightness temperature imaging and dielectric properties ...

    Indian Academy of Sciences (India)

    In this paper,we give a rough analysis of the microwave brightness temperature images of the lunar disc observed using the NRAO 12 meter Telescope and Siberian Solar Radio Telescope.We also ... Center for Space Science and Applied Research, Chinese Academy of Sciences, P.O. Box 8701, Beijing 100 080, China.

  17. Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques.

    Science.gov (United States)

    Mohammed, Muzaffer; Clement, Travis C; Aslan, Kadir

    2014-12-02

    In this paper, we present the design of four different circular bioassay platforms, which are suitable for homogeneous microwave heating, using theoretical calculations (i.e., COMSOL™ multiphysics software). Circular bioassay platforms are constructed from poly(methyl methacrylate) (PMMA) for optical transparency between 400-800 nm, has multiple sample capacity (12, 16, 19 and 21 wells) and modified with silver nanoparticle films (SNFs) to be used in microwave-accelerated bioassays (MABs). In addition, a small monomode microwave cavity, which can be operated with an external microwave generator (100 W), for use with the bioassay platforms in MABs is also developed. Our design parameters for the circular bioassay platforms and monomode microwave cavity during microwave heating were: (i) temperature profiles, (ii) electric field distributions, (iii) location of the circular bioassay platforms inside the microwave cavity, and (iv) design and number of wells on the circular bioassay platforms. We have also carried out additional simulations to assess the use of circular bioassay platforms in a conventional kitchen microwave oven (e.g., 900 W). Our results show that the location of the circular bioassay platforms in the microwave cavity was predicted to have a significant effect on the homogeneous heating of these platforms. The 21-well circular bioassay platform design in our monomode microwave cavity was predicted to offer a homogeneous heating pattern, where inter-well temperature was observed to be in between 23.72-24.13°C and intra-well temperature difference was less than 0.21°C for 60 seconds of microwave heating, which was also verified experimentally.

  18. Using Multi Resonance Effects Towards Single Conformer Microwave Spectroscopy

    Science.gov (United States)

    Abeysekera, Chamara; Hernandez-Castillo, Alicia O.; Hays, Brian M.; Zwier, Timothy S.

    2016-06-01

    The relationship between the molecular structure and rotational frequencies makes rotational spectroscopy highly structural specific and an ideal tool for complex mixture analysis. The modern developments in broadband microwave techniques have immensely reduced the data acquisition time, while creating a need for high speed data analysis procedures. A new microwave-microwave double resonance method will be introduced, to perform single conformer/isomer microwave spectroscopy in complex chemical mixtures. The method combines the selective excitation schemes possible in chirped pulse microwave spectroscopy with multi-resonance effects observed upon sweeping in the rapid adiabatic passage regime, enabling perturbations to be induced in the intensities of most of the transitions ascribable to a single molecular constituent (e.g. a conformational isomer) in a mixture. Details of the method, experimental implementation and future challenges will be discussed.

  19. Microwave engineering concepts and fundamentals

    CERN Document Server

    Khan, Ahmad Shahid

    2014-01-01

    Detailing the active and passive aspects of microwaves, Microwave Engineering: Concepts and Fundamentals covers everything from wave propagation to reflection and refraction, guided waves, and transmission lines, providing a comprehensive understanding of the underlying principles at the core of microwave engineering. This encyclopedic text not only encompasses nearly all facets of microwave engineering, but also gives all topics—including microwave generation, measurement, and processing—equal emphasis. Packed with illustrations to aid in comprehension, the book: •Describes the mathematical theory of waveguides and ferrite devices, devoting an entire chapter to the Smith chart and its applications •Discusses different types of microwave components, antennas, tubes, transistors, diodes, and parametric devices •Examines various attributes of cavity resonators, semiconductor and RF/microwave devices, and microwave integrated circuits •Addresses scattering parameters and their properties, as well a...

  20. SETI Searches for Radio Transients from Kepler Field Planets and Astropulse Candidates

    Science.gov (United States)

    Gautam, Abhimat Krishna; Siemion, Andrew; Korpela, Eric J.; Cobb, Jeff; Lebofsky, Matt; Werthimer, Dan

    2014-06-01

    We present a search for fast radio transients in targeted observations of planet candidates in the Kepler Field and candidate Astropulse sources.Kepler Field observations were conducted in the band 1.1 and 1.9 GHz using the Green Bank Telescope in Green Bank, West Virginia and are centered on 86 stars hosting candidate planets identified by the Kepler spacecraft. These stars were chosen based on the properties of their putative planetary system thought to be conducive to the development of advanced life, including all systems known (as of May 2011) hosting a Kepler Object of Interest (KOI) with a calculated equilibrium temperature between 230 and 380 K, at least 4 KOIs or a KOI with an inferred radius 50 d. The Kepler Field is centered at an intermediate galactic latitude, b = 13.5°, which presents an additional opportunity to detect signals from the older population of millisecond and recycled pulsars located above the galactic plane.The Astropulse radio survey searches for brief wide-band pulses in a 2.5 MHz band centered at 1420 MHz using commensal data recorded from the Arecibo ALFA receiver. In early Astropulse analysis, 108 candidate sources were identified that passed a series of tests designed to eliminate potential sources of radio frequency interference (RFI). We have performed targeted re-observations of these sources at Arecibo over the full (1214-1536 MHz) ALFA band.We have developed a software pipeline to locate fast dispersed transients in these observations, leveraging components of the PRESTO software library. This pipeline consists of finding and removing RFI, conducting de-dispersion to remove the effects of dispersion from the interstellar medium (ISM) on the signal and identifying over- threshold events. We also perform de-dispersion at negative dispersion measures, proposed to be a potential technique for intelligent civilizations to distinguish their emission from natural sources. We carry out both a periodicity and single-pulse search on de

  1. The scientific base of heating water by microwave

    Science.gov (United States)

    Akdoǧan, Ender; ćiftçi, Muharrem

    2016-03-01

    This article is based on the master thesis [4] related to our invention which was published in World Intellectual Property Organization (WO/2011/048506) as a microwave water heater. In the project, a prototype was produced to use microwave in industrial heating. In order to produce the prototype, the most appropriate material kind for microwave-water experiments was determined by a new energy loss rate calculation technique. This new energy loss calculation is a determinative factor for material permeability at microwave frequency band (1-100 GHz). This experimental series aim to investigate the rationality of using microwave in heating industry. Theoretically, heating water by microwave (with steady frequency 2.45 GHz) is analyzed from sub-molecular to Classical Mechanic results of heating. In the study, we examined Quantum Mechanical base of heating water by microwave experiments. As a result, we derived a Semi-Quantum Mechanical equation for microwave-water interactions and thus, Wien displacement law can be derived to verify experimental observations by this equation.

  2. The scientific base of heating water by microwave

    Energy Technology Data Exchange (ETDEWEB)

    Akdoğan, Ender, E-mail: ender.akdogan@tpe.gov.tr [Department of Physics Engineering, Ankara University, Dögol St. Tandoğan Ankara 06560 Türkiye (Turkey); Çiftçi, Muharrem, E-mail: muharrem-ciftci@windowslive.com [Author" 1 Department of Physics, Ankara University, Dögol St. Tandoğan Ankara 06560 Türkiye (Turkey)

    2016-03-25

    This article is based on the master thesis [4] related to our invention which was published in World Intellectual Property Organization (WO/2011/048506) as a microwave water heater. In the project, a prototype was produced to use microwave in industrial heating. In order to produce the prototype, the most appropriate material kind for microwave-water experiments was determined by a new energy loss rate calculation technique. This new energy loss calculation is a determinative factor for material permeability at microwave frequency band (1-100 GHz). This experimental series aim to investigate the rationality of using microwave in heating industry. Theoretically, heating water by microwave (with steady frequency 2.45 GHz) is analyzed from sub-molecular to Classical Mechanic results of heating. In the study, we examined Quantum Mechanical base of heating water by microwave experiments. As a result, we derived a Semi-Quantum Mechanical equation for microwave-water interactions and thus, Wien displacement law can be derived to verify experimental observations by this equation.

  3. Simulations of the Microwave Sky

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, Neelima; /KIPAC, Menlo Park; Bode, Paul; /Princeton U., Astrophys. Sci. Dept.; Das, Sudeep; /Princeton U., Astrophys. Sci. Dept. /Princeton U.; Hernandez-Monteagudo, Carlos; /Garching, Max Planck Inst.; Huffenberger, Kevin; /Miami U.; Lin, Yen-Ting; /Tokyo U., IPMU; Ostriker, Jeremiah P.; /Princeton U., Astrophys. Sci. Dept.; Trac, Hy; /Harvard-Smithsonian Ctr. Astrophys.

    2009-12-16

    We create realistic, full-sky, half-arcminute resolution simulations of the microwave sky matched to the most recent astrophysical observations. The primary purpose of these simulations is to test the data reduction pipeline for the Atacama Cosmology Telescope (ACT) experiment; however, we have widened the frequency coverage beyond the ACT bands and utilized the easily accessible HEALPix map format to make these simulations applicable to other current and near future microwave background experiments. Some of the novel features of these simulations are that the radio and infrared galaxy populations are correlated with the galaxy cluster and group populations, the primordial microwave background is lensed by the dark matter structure in the simulation via a ray-tracing code, the contribution to the thermal and kinetic Sunyaev-Zel'dovich (SZ) signals from galaxy clusters, groups, and the intergalactic medium has been included, and the gas prescription to model the SZ signals has been refined to match the most recent X-ray observations. The cosmology adopted in these simulations is also consistent with the WMAP 5-year parameter measurements. From these simulations we find a slope for the Y{sub 200} - M{sub 200} relation that is only slightly steeper than self-similar, with an intrinsic scatter in the relation of {approx} 14%. Regarding the contamination of cluster SZ flux by radio galaxies, we find for 148 GHz (90 GHz) only 3% (4%) of halos have their SZ decrements contaminated at a level of 20% or more. We find the contamination levels higher for infrared galaxies. However, at 90 GHz, less than 20% of clusters with M{sub 200} > 2.5 x 10{sup 14}M{sub {circle_dot}} and z < 1.2 have their SZ decrements filled in at a level of 20% or more. At 148 GHz, less than 20% of clusters with M{sub 200} > 2.5 x 10{sup 14}M{sub {circle_dot}} and z < 0.8 have their SZ decrements filled in at a level of 50% or larger. Our models also suggest that a population of very high flux

  4. Vortices at Microwave Frequencies

    Science.gov (United States)

    Silva, Enrico; Pompeo, Nicola; Dobrovolskiy, Oleksandr V.

    2017-11-01

    The behavior of vortices at microwave frequencies is an extremely useful source of information on the microscopic parameters that enter the description of the vortex dynamics. This feature has acquired particular relevance since the discovery of unusual superconductors, such as cuprates. Microwave investigation then extended its field of application to many families of superconductors, including the artificially nanostructured materials. It is then important to understand the basics of the physics of vortices moving at high frequency, as well as to understand what information the experiments can yield (and what they can not). The aim of this brief review is to introduce the readers to some basic aspects of the physics of vortices under a microwave electromagnetic field, and to guide them to an understanding of the experiment, also by means of the illustration of some relevant results.

  5. Physics of the Microwave Oven

    Science.gov (United States)

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  6. Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes

    Science.gov (United States)

    Seng, Lee Yeng; Wee, F. H.; Rahim, H. A.; AbdulMalek, MohamedFareq; You, Y. K.; Liyana, Z.; Ezanuddin, A. A. M.

    2017-01-01

    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2-18 GHz. An improvement of microwave absorption <-20 dB is observed with respect to a high lossy composite placed at bottom layer of multiple layers. Reflectivity evaluations indicate that the composites display a great potential application as wideband electromagnetic wave absorbers.

  7. Microwave analog of Stern-Gerlach effects using nonuniform chiral metamaterials

    Science.gov (United States)

    Tomita, Satoshi; Sawada, Kei; Nagai, Shotaro; Sanada, Atsushi; Hisamoto, Nobuyuki; Ueda, Tetsuya

    2017-10-01

    This study observes microwave beam splitting dependent on circular polarizations through nonuniform chiral metamaterials. Nonuniform chiral metamaterials with a gradation in refractive index are constructed using chiral meta-atoms that exhibit optical activities at microwave frequencies. Microwave scattering far-field patterns by the nonuniform chiral metamaterials demonstrate a deflection of microwaves, which transmit in a direction perpendicular to the refractive index gradient. Furthermore, circularly polarized microwaves with opposite "spins of light" go their separate ways in the nonuniform chiral metamaterials. This phenomenon is an optical analog of the Stern-Gerlach effects for electrons.

  8. New automated microwave heating process for cooking and pasteurization of microwaveable foods containing raw meats.

    Science.gov (United States)

    Huang, Lihan; Sites, Joseph

    2010-03-01

    A new microwave heating process was developed for cooking microwaveable foods containing raw meats. A commercially available inverter-based microwave oven was modified for pasteurization of mechanically tenderized beef, inoculated with Escherichia coli O157:H7 (approximately 5 log(10) CFU/g) and packaged in a 12-oz CPET tray containing 150-mL de-ionized water. The new microwave heating system was equipped with an infrared sensor and a proportional feedback mechanism to allow temperature controlled microwave heating. A 2-stage heating strategy was adopted to cook the product. In the primary heating stage, the sample surface temperature was increased to an initial temperature set-point (ITSP, 65, 70, 75, or 80 degrees C). In the secondary heating stage, the heating was continued with a small fraction of microwave power. The effect of ITSP, hold time (0 to 3 min), and sample elevation (0, 0.03, and 0.07 m above turntable) on inactivation of E. coli O157:H7 and background microflora was evaluated. It was observed that only a small number (approximately 1.3 logs) of E. coli O157:H7 and background microflora were inactivated in the primary heating stage. The elevation 0.07 m, which was in the proximity of the geometric center of the metal cavity, was more effective in inactivating both E. coli O157:H7 and background microflora. Substantially more bacteria were inactivated in the secondary heating stage. Complete inactivation of E. coli and background microflora was observed with heating at temperatures above 70 degrees C for more than 1 min. This study demonstrated a new approach for ensuring the safety of microwaveable products containing raw meats.

  9. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  10. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  11. Is the Wilkins Ice Shelf a Firn Aquifer? Spaceborne Observation of Subsurface Winter Season Liquid Meltwater Storage on the Antarctic Peninsula using Multi-Frequency Active and Passive Microwave Remote Sensing

    Science.gov (United States)

    Miller, J.; Scambos, T.; Forster, R. R.; Long, D. G.; Ligtenberg, S.; van den Broeke, M.; Vaughan, D. G.

    2015-12-01

    Near-surface liquid meltwater on ice shelves has been inferred to influence ice shelf stability if it induces hydrofracture and is linked to disintegration events on the Larsen B and the Wilkins ice shelves on the Antarctic Peninsula during the summer months. While the initial Wilkins disintegration event occurred in March of 2009, two smaller disintegration events followed in May and in July of that year. It has long been assumed meltwater refreezes soon after surface melt processes cease. Given this assumption, an earlier hypothesis for the two winter season disintegration events was hydrofracture via a brine infiltration layer. Two lines of evidence supported this hypothesis 1) early airborne radar surveys did not record a reflection from the bottom of the ice shelf, and 2) a shallow core drilled in 1972 on the Wilkins encountered liquid water at a depth of ~7 m. The salinity of the water and the temperature at the base of the core, however, were not described. The recent discovery of winter season liquid meltwater storage on the Greenland ice sheet has changed perceptions on meltwater longevity at depth in firn. Evidence of Greenland's firn aquifer includes liquid meltwater encountered in shallow firn cores at 5 m depth and a lack of reflections from the base of the ice sheet in airborne surveys. Thus, previous lines of evidence suggesting brine infiltration may alternatively suggest the presence of a perennial firn aquifer. We recently demonstrated the capability for observation of Greenland's firn aquifer from space using multi-frequency active and passive microwave remote sensing. This research exploits the retrieval technique developed for Greenland to provide the first spaceborne mappings of winter season liquid meltwater storage on the Wilkins. We combine L-band brightness temperature and backscatter data from the MIRAS instrument (1.4 GHz) aboard ESA's Soil Moisture and Ocean Salinity mission and the radar (1.3 GHZ) and radiometer(1.4 GHz) aboard NASA

  12. Ultraviolet Light Source Using Electrodeless Microwave Discharge

    Science.gov (United States)

    Nishikawa, Taku; Toyoda, Hirotaka

    2015-09-01

    Surface treatment technologies using ultraviolet (UV) light, such as organic residue removal, surface modification or sterilization, are widely used. So far, UV lamps using DC discharge with electrodes inside the lamp tube is commonly used. However, sputtering of electrode materials sometimes causes deposition on the inner tube surface as well as degradation of the electrodes, resulting in short life time of the lamp tube. In this study, we propose an electrodeless UV mercury (Hg) lamp source using microwave power. 2.45 GHz Microwave power (<4 kW) from a power supply is divided into four power lines using branch waveguides. A mercury lamp tube (diameter: 9.6 mm, length: 42 cm, Hg: 13.5 mg, Ar: 1 Torr) is inserted into the branch waveguides and microwave power is coupled to the plasma. Emission from the lamp is monitored by a monochromator and an 254 nm UV monitor. Lamp temperature is also measured by a thermography camera and tube temperature up to 900 K with good uniformity along ~ 30 cm was observed. Uniformity of the 254 nm UV light intensity was +15 % along the lamp tube. The maximum UV light intensity of 64 mW/cm2 was observed at a microwave power of 4 kW.

  13. The influence of microwave radiation on the failure of rocks

    Directory of Open Access Journals (Sweden)

    Lovás Michal

    2000-09-01

    Full Text Available The heating and processing of materials using microwaves becomes increasingly popular for industrial applications. Compared to conventional heating, microwave processing can provide a rapid, the production of materials with unique properties, and reductions in manufacturing costs and processing times.The positive influence of the microwave radiation on the faulting of the individual rocks is described. At the heating of the heterogeneous ores, the microwaves have an selective effect for individual mineral components. Owing to the different degree of to heating and thermal dilatation the stress and destructive attendants arise, which increase the faulting of rocks. The rate of the faulting has been investigated on the basis of measurement of the elastic waves motion velocity by the impulse-dynamic method.On the basis of the measured values of elastic wave motion in the observed rocks before and after their microwave heating the coefficient of faulting was computed according to the relation (1. Subsequently, from these coefficients the rate of faulting was determined for individual rocks according to Jaeger (Table 1.Various rate of rocks faulting caused by the radiation depend on their ability to absorb microwave power. High rate of faulting was observed in rocks with strong absorption of microwave power unlike from substances which weakly absorb the radiation. Particularly, a high rate of faulting after microwave heating was observed at samples of limestone (Rožòava-Jovice and magnesite (Haèava. Low rate of faulting was obtained in the case of granodiorite (Podhradová, granite (Hnilec, sandstone (Horelica, marble (Koelga and andesite (Hubošovce.The influence of microwave energy on the rate of rocks faulting was confirmed. The new knowledge can be applied for the intensification of the rock disintegration processes.

  14. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  15. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain f...

  16. Nonlinear Microwave Optomechanics

    NARCIS (Netherlands)

    Shevchuk, O.

    2017-01-01

    The nonlinearity is essential for creation of non-classical states of the cavity or mechanical resonator such as squeezed or cat states. A microwave cavity can be made nonlinear by, for instance, adding Josephson junctions. The mechanical resonator is inherently nonlinear. The radiation pressure

  17. Mid-Latitude Snowmelt Onset Detection Via Microwave Remote Sensing

    Science.gov (United States)

    Vuyovich, C.; Jacobs, J. M.; Osborne, D.; Hunsaker, A. G.; Tuttle, S. E.

    2016-12-01

    The timing and magnitude of spring snowmelt events are critical for understanding the winter-to-spring transition of the hydrologic cycle and ecosystem processes. Melt timing determination is challenging because snowpack ripening observations are seldom available. Remotely sensed passive microwave observations show promise for determining snowpack wetting and melt onset at global scales. Studies performed in northern latitude regions verify the theoretical concept of microwave snowmelt detection methods under ideal conditions. However, early winter snowmelt events within mid-latitude regions introduce large regional climate differences that add considerable amounts of noise to the microwave observations. Diurnal Amplitude Variation (DAV), Frequency Difference (FD) and Polarization Ratio (PR) are three methods that use remotely sensed passive microwave observations to determine snowpack wetting and melt onset. This study evaluates the performance of these approaches to determine spring melt onset and early winter flood events in mid-latitudes. The suitability of microwave remote sensing techniques to detect snowmelt was found to vary regionally. Physical characteristics including basin latitude, regional air temperatures, snow depth, snow covered area, forest density, and rain intensity were examined to understand how and why the observed microwave signatures associated with snow cover vary over contrasting regions.

  18. Comparison of carrot (Daucus carota drying in microwave and in vacuum microwave

    Directory of Open Access Journals (Sweden)

    R. Béttega

    2014-06-01

    Full Text Available Drying is a single operation employed to prolong the life of a large quantity of vegetables. Carrot (Daucus carota drying has been the subject of many studies. This plant has been highlighted in the human diet for having high nutritional value, mainly due to the high content of β-carotene. In this work, carrot drying behavior was studied in a regular microwave dryer and a vacuum microwave dryer. A vacuum of 450 mmHg was applied for drying of carrot in different geometrical shapes (cubes, discs and sticks. The samples were dried at power ratings of 1.0 W/g, 1.5 W/g and 2.0 W/g for both methods of drying. The evolution of physical properties such as density, volume and porosity was monitored and related to the moisture content of the sample and to the method of drying and power rating used. The geometric shape of the sample influenced the drying kinetics and it was verified that the cubic form was responsible for a slower drying. The application of vacuum showed no major changes in the drying kinetics in microwave but influenced the physical properties of the material. The influence of power ratings on the content of β-carotene was also evaluated and discussed. The main difference observed was the lower shrinkage of the samples dried in the vacuum microwave compared to those dried only in microwave.

  19. Industrial scale microwave processing of tomato juice using a novel continuous microwave system.

    Science.gov (United States)

    Stratakos, Alexandros Ch; Delgado-Pando, Gonzalo; Linton, Mark; Patterson, Margaret F; Koidis, Anastasios

    2016-01-01

    This study evaluated the effect of an industrial scale continuous flow microwave volumetric heating system in comparison to conventional commercial scale pasteurisation for the processing of tomato juice in terms of physicochemical properties, microbial characteristics and antioxidant capacity. The effect against oxidative stress in Caco-2 cells, after in vitro digestion was also investigated. Physicochemical and colour characteristics of juices were very similar between technologies and during storage. Both conventional and microwave pasteurisation inactivated microorganisms and kept them in low levels throughout storage. ABTS[Symbol: see text](+) values, but not ORAC, were higher for the microwave pasteurised juice at day 0 however no significant differences between juices were observed during storage. Juice processed with the microwave system showed an increased cytoprotective effect against H2O2 induced oxidation in Caco-2 cells. Organoleptic analysis revealed that the two tomato juices were very similar. The continuous microwave volumetric heating system appears to be a viable alternative to conventional pasteurisation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Microwave chemistry: Effect of ions on dielectric heating in microwave ovens

    Directory of Open Access Journals (Sweden)

    Jamil Anwar

    2015-01-01

    Full Text Available To understand the interactions of microwaves with dielectric materials and their conversion to thermal energy in aqueous systems, the effect of ionic concentration has been studied. Aqueous solutions of inorganic ions were exposed to microwaves (2.45 GHz in a modified oven under identical conditions. Difference in solution temperatures with reference to pure (deionized water was monitored in each case. A significant decrease in the temperature was observed with an increase in the quantity of ions. Experiments were repeated with several inorganic ions varying in size and charge. The information can be helpful in understanding the role of ions during dielectric heating.

  1. Microwave-Assisted Olefin Metathesis

    Science.gov (United States)

    Nicks, François; Borguet, Yannick; Sauvage, Xavier; Bicchielli, Dario; Delfosse, Sébastien; Delaude, Lionel; Demonceau, Albert

    Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared to conventional heating methods. The present contribution aims at illustrating the advantages of this technology in olefin metathesis and, when data are available, at comparing microwave-heated and conventionally heated experiments

  2. Introduction to Microwave Linear [Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, David H

    1999-01-04

    The elements of microwave linear accelerators are introduced starting with the principles of acceleration and accelerating structures. Considerations for microwave structure modeling and design are developed from an elementary point of view. Basic elements of microwave electronics are described for application to the accelerator circuit and instrumentation. Concepts of beam physics are explored together with examples of common beamline instruments. Charged particle optics and lattice diagnostics are introduced. Considerations for fixed-target and colliding-beam experimentation are summarized.

  3. An introduction to microwave measurements

    CERN Document Server

    Basu, Ananjan

    2014-01-01

    IntroductionAim and ScopeGeneral Electronic Measurements and Frequency LimitationsApplications and Importance of Microwave MeasurementsOverview of State-of-the-Art Microwave MeasurementsReferencesBackground InformationS-Parameters and Related Black-Box RepresentationSpectra of Commonly Encountered SignalsMicrowave Filters and Directional CouplersMicrowave Mixers, Switches, Attenuators, and ConnectorsConclusionProblemsReferencesTraditional Measurement TechniquesThe Power MeterTransmission MeasurementReflection MeasurementConclusionProblemsReferencesVector Network AnalyzerEnhancement of Scalar M

  4. Relativistic-microwave theory of ball lightning

    OpenAIRE

    H.-C. Wu

    2016-01-01

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by partic...

  5. The Microwave SQUID Multiplexer

    Science.gov (United States)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  6. Non-Ionizing Radiation Used in Microwave Ovens

    Science.gov (United States)

    ... in Microwave Ovens Non-Ionizing Radiation Used in Microwave Ovens Explore the interactive, virtual community of RadTown USA ! ... learn more About Non-Ionizing Radiation Used in Microwave Ovens Microwave Oven. Microwave ovens use electromagnetic waves that ...

  7. Results from the Wilkinson Microwave Anisotropy Probe

    Science.gov (United States)

    Komatsu, E.; Bennett, Charles L.; Komatsu, Eiichiro

    2015-01-01

    The Wilkinson Microwave Anisotropy Probe (WMAP) mapped the distribution of temperature and polarization over the entire sky in five microwave frequency bands. These full-sky maps were used to obtain measurements of temperature and polarization anisotropy of the cosmic microwave background with the unprecedented accuracy and precision. The analysis of two-point correlation functions of temperature and polarization data gives determinations of the fundamental cosmological parameters such as the age and composition of the universe, as well as the key parameters describing the physics of inflation, which is further constrained by three-point correlation functions. WMAP observations alone reduced the flat ? cold dark matter (Lambda Cold Dark Matter) cosmological model (six) parameter volume by a factor of > 68, 000 compared with pre-WMAP measurements. The WMAP observations (sometimes in combination with other astrophysical probes) convincingly show the existence of non-baryonic dark matter, the cosmic neutrino background, flatness of spatial geometry of the universe, a deviation from a scale-invariant spectrum of initial scalar fluctuations, and that the current universe is undergoing an accelerated expansion. The WMAP observations provide the strongest ever support for inflation; namely, the structures we see in the universe originate from quantum fluctuations generated during inflation.

  8. More Experiments with Microwave Ovens

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular…

  9. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue,

  10. Microwave drying of wood strands

    Science.gov (United States)

    Guanben Du; Siqun Wang; Zhiyong Cai

    2005-01-01

    Characteristics of microwave drying of wood strands with different initial moisture contents and geometries were investigated using a commercial small microwave oven under different power inputs. Temperature and moisture changes along with the drying efficiency were examined at different drying scenarios. Extractives were analyzed using gas chromatography=mass...

  11. Computer-Generated Microwave Holograms.

    Science.gov (United States)

    Leming, Charles W.; Hastings, Orestes Patterson, III

    1980-01-01

    Described is the phasor method of superposition of waves. The intensity pattern from a system of microwave sources is calculated point by point on a plane corresponding to a film emulsion, and then printed and directly converted to a hologram for 3-cm microwaves. Calculations, construction, and viewing of holograms are included. (Author/DS)

  12. Advances on integrated microwave photonics

    DEFF Research Database (Denmark)

    Dong, Jianji; Liao, Shasha; Yan, Siqi

    2017-01-01

    Integrated microwave photonics has attracted a lot of attentions and makes significant improvement in last 10 years. We have proposed and demonstrated several schemes about microwave photonics including waveform generation, signal processing and energy-efficient micro-heaters. Our schemes are all...... fabricated on silicon-on-insulator chips and have advantages of compactness and capability to integrate with electronics....

  13. Microstrip microwave band gap structures

    Indian Academy of Sciences (India)

    Microwave band gap structures exhibit certain stop band characteristics based on the periodicity, impedance contrast and effective refractive index contrast. These structures though formed in one-, two- and three-dimensional periodicity, are huge in size. In this paper, microstrip-based microwave band gap structures are ...

  14. Microwave and Pulsed Power

    Energy Technology Data Exchange (ETDEWEB)

    Freytag, E.K.

    1993-03-01

    The goals of the Microwave and Pulsed Power thrust area are to identify realizable research and development efforts and to conduct high-quality research in those pulse power and microwave technologies that support existing and emerging programmatic requirements at Lawrence Livermore National Laboratory (LLNL). Our main objective is to work on nationally important problems while enhancing our basic understanding of enabling technologies such as component design and testing, compact systems packaging, exploratory physics experiments, and advanced systems integration and performance. During FY-92, we concentrated our research efforts on the six project areas described in this report. (1) We are investigating the superior electronic and thermal properties of diamond that may make it an ideal material for a high-power, solid-state switch. (2) We are studying the feasibility of using advanced Ground Penetrating Imaging Radar technology for reliable non-destructive evaluation of bridges and other high-value concrete structures. These studies include conceptual designs, modeling, experimental verifications, and image reconstruction of simulated radar data. (3) We are exploring the efficiency of pulsed plasma processing techniques used for the removal of NO{sub x} from various effluent sources. (4) We have finished the investigation of the properties of a magnetically delayed low-pressure gas switch, which was designed here at LLNL. (5) We are applying statistical electromagnetic theory techniques to help assess microwave effects on electronic subsystems, by using a mode stirred chamber as our measurement tool. (6) We are investigating the generation of perfluoroisobutylene (PFIB) in proposed CFC replacement fluids when they are subjected to high electrical stresses and breakdown environments.

  15. Relativistic-microwave theory of ball lightning

    Science.gov (United States)

    Wu, H.-C.

    2016-06-01

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

  16. Influence of plasma turbulence on microwave propagation

    Science.gov (United States)

    Köhn, A.; Holzhauer, E.; Leddy, J.; Thomas, M. B.; Vann, R. G. L.

    2016-11-01

    It is not fully understood how electromagnetic waves propagate through plasma density fluctuations when the size of the fluctuations is comparable with the wavelength of the incident radiation. In this paper, the perturbing effect of a turbulent plasma density layer on a traversing microwave beam is simulated with full-wave simulations. The deterioration of the microwave beam is calculated as a function of the characteristic turbulence structure size, the turbulence amplitude, the depth of the interaction zone and the size of the waist of the incident beam. The maximum scattering is observed for a structure size on the order of half the vacuum wavelength. The scattering and beam broadening was found to increase linearly with the depth of the turbulence layer and quadratically with the fluctuation strength. Consequences for experiments and 3D effects are considered.

  17. Effects of feedstock characteristics on microwave-assisted pyrolysis - A review.

    Science.gov (United States)

    Zhang, Yaning; Chen, Paul; Liu, Shiyu; Peng, Peng; Min, Min; Cheng, Yanling; Anderson, Erik; Zhou, Nan; Fan, Liangliang; Liu, Chenghui; Chen, Guo; Liu, Yuhuan; Lei, Hanwu; Li, Bingxi; Ruan, Roger

    2017-04-01

    Microwave-assisted pyrolysis is an important approach to obtain bio-oil from biomass. Similar to conventional electrical heating pyrolysis, microwave-assisted pyrolysis is significantly affected by feedstock characteristics. However, microwave heating has its unique features which strongly depend on the physical and chemical properties of biomass feedstock. In this review, the relationships among heating, bio-oil yield, and feedstock particle size, moisture content, inorganics, and organics in microwave-assisted pyrolysis are discussed and compared with those in conventional electrical heating pyrolysis. The quantitative analysis of data reported in the literature showed a strong contrast between the conventional processes and microwave based processes. Microwave-assisted pyrolysis is a relatively new process with limited research compared with conventional electrical heating pyrolysis. The lack of understanding of some observed results warrant more and in-depth fundamental research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Microwave based nanogenerator using the ratchet effect in Si/SiGe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bisotto, I; Kannan, E S; Sassine, S; Portal, J-C [LNCMI, UPR 3228, CNRS-INSA-UJF-UPS, BP 166, 38042 Grenoble, Cedex 9 (France); Murali, R; Beck, T J [Microelectronics Research Center Georgia Institute of Technology, 791 Atlantic Drive NW, Atlanta, GA 30332 (United States); Jalabert, L [LIMMS/CNRS-IIS, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8505, Tokyo (Japan)

    2011-06-17

    Ratchet based microwave current generators and detectors were developed in Si/SiGe heterostructures for wireless communication with the possibility of extending the detection limit to the terahertz range. A microwave induced ratchet current was generated in the two-dimensional electron gas by patterning an array of semicircular antidots in hexagonal geometry. The spatial asymmetry created by the semicircular antidots forces the electrons under the influence of the microwave electric field to move preferentially towards the direction of the semidisc axis. A photovoltage of the order of few millivolts was observed. Such a photovoltage was completely absent in a symmetric system consisting of circular antidots. The induced photovoltage increased monotonically with microwave power and was found to be independent of the microwave polarization. This device opens the possibility of employing silicon based heterostructures for nanogenerators and other wireless communication devices using microwaves.

  19. Microwave systems design

    CERN Document Server

    Awang, Zaiki

    2014-01-01

    The aim of this book is to serve as a design reference for students and as an up-to-date reference for researchers. It also acts as an excellent introduction for newcomers to the field and offers established rf/microwave engineers a comprehensive refresher.  The content is roughly classified into two – the first two chapters provide the necessary fundamentals, while the last three chapters focus on design and applications. Chapter 2 covers detailed treatment of transmission lines. The Smith chart is utilized in this chapter as an important tool in the synthesis of matching networks for microwave amplifiers. Chapter 3 contains an exhaustive review of microstrip circuits, culled from various references. Chapter 4 offers practical design information on solid state amplifiers, while Chapter 5 contains topics on the design of modern planar filters, some of which were seldom published previously. A set of problems at the end of each chapter provides the readers with exercises which were compiled from actual uni...

  20. Pyrolysis of tyre powder using microwave thermogravimetric analysis: Effect of microwave power.

    Science.gov (United States)

    Song, Zhanlong; Yang, Yaqing; Zhou, Long; Zhao, Xiqiang; Wang, Wenlong; Mao, Yanpeng; Ma, Chunyuan

    2017-02-01

    The pyrolytic characteristics of tyre powder treated under different microwave powers (300, 500, and 700 W) were studied via microwave thermogravimetric analysis. The product yields at different power levels were studied, along with comparative analysis of microwave pyrolysis and conventional pyrolysis. The feedstock underwent preheating, intense pyrolysis, and final pyrolysis in sequence. The main and secondary weight loss peaks observed during the intense pyrolysis stage were attributed to the decomposition of natural rubbers and synthetic rubbers, respectively. The total mass loss rates, bulk temperatures, and maximum temperatures were distinctively higher at higher powers. However, the maximum mass loss rate (0.005 s(-1)), the highest yields of liquid product (53%), and the minimum yields of residual solid samples (43.83%) were obtained at 500 W. Compared with conventional pyrolysis, microwave pyrolysis exhibited significantly different behaviour with faster reaction rates, which can decrease the decomposition temperatures of both natural and synthetic rubber by approximately 110 °C-140 °C.

  1. Microwave power coupling with electron cyclotron resonance ...

    Indian Academy of Sciences (India)

    The effect of microwave power coupling to the plasma was studied by varying the microwave power. ... plasma is produced by the interaction of microwave radiation, in the presence of appro- priate magnetic field ... microwaves are used in resonant mode to couple the electromagnetic energy to the plasma for generating ...

  2. Autophagy mediates the degradation of synaptic vesicles: A potential mechanism of synaptic plasticity injury induced by microwave exposure in rats.

    Science.gov (United States)

    Hao, Yanhui; Li, Wenchao; Wang, Hui; Zhang, Jing; Yu, Chao; Tan, Shengzhi; Wang, Haoyu; Xu, Xinping; Dong, Ji; Yao, Binwei; Zhou, Hongmei; Zhao, Li; Peng, Ruiyun

    2018-02-03

    To explore how autophagy changes and whether autophagy is involved in the pathophysiological process of synaptic plasticity injury caused by microwave radiation, we established a 30 mW/cm 2 microwave-exposure in vivo model, which caused reversible injuries in rat neurons. Microwave radiation induced cognitive impairment in rats and synaptic plasticity injury in rat hippocampal neurons. Autophagy in rat hippocampal neurons was activated following microwave exposure. Additionally, we observed that synaptic vesicles were encapsulated by autophagosomes, a phenomenon more evident in the microwave-exposed group. Colocation of autophagosomes and synaptic vesicles in rat hippocampal neurons increased following microwave exposure. microwave exposure led to the activation of autophagy in rat hippocampal neurons, and excessive activation of autophagy might damage synaptic plasticity by mediating synaptic vesicle degradation. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Microwave mixer technology and applications

    CERN Document Server

    Henderson, Bert

    2013-01-01

    Although microwave mixers play a critical role in wireless communication and other microwave applications employing frequency conversion circuits, engineers find that most books on this subject emphasize theoretical aspects, rather than practical applications. That's about to change with the forthcoming release of Microwave Mixer Technology and Applications. Based on a review of over one thousand patents on mixers and frequency conversion, authors Bert Henderson and Edmar Camargo have written a comprehensive book for mixer designers who want solid ideas for solving their own design challenges.

  4. Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes

    KAUST Repository

    Julfakyan, Khachatur

    2015-08-06

    Polydopamine-coated FeCo nanocubes (PDFCs) were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm2 power. These particles were found to be non-toxic in the absence of irradiation, but gained significant toxicity upon irradiation. Interestingly, no increase in relative heating rate was observed when the PDFCs were irradiated in solution, eliminating nanoparticle (NP)-induced thermal ablation as the source of toxicity. Based on these studies, we propose that microwave-induced redox processes generate the observed toxicity. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

  5. Physics of the Cosmic Microwave Background and the Planck Mission

    CERN Document Server

    Kurki-Suonio, Hannu

    2012-01-01

    This lecture is a sketch of the physics of the cosmic microwave background. The observed anisotropy can be divided into four main contributions: variations in the temperature and gravitational potential of the primordial plasma, Doppler effect from its motion, and a net red/blueshift the photons accumulate from traveling through evolving gravitational potentials on their way from the primordial plasma to here. These variations are due to primordial perturbations, probably caused by quantum fluctuations in the very early universe. The ongoing Planck satellite mission to observe the cosmic microwave background is also described.

  6. Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes

    Science.gov (United States)

    Julfakyan, Khachatur; Fatieiev, Yevhen; Alsaiari, Shahad; Deng, Lin; Ezzeddine, Alaa; Zhang, Dingyuan; Rotello, Vincent M.; Khashab, Niveen M.

    2015-01-01

    Polydopamine-coated FeCo nanocubes (PDFCs) were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm2 power. These particles were found to be non-toxic in the absence of irradiation, but gained significant toxicity upon irradiation. Interestingly, no increase in relative heating rate was observed when the PDFCs were irradiated in solution, eliminating nanoparticle (NP)-induced thermal ablation as the source of toxicity. Based on these studies, we propose that microwave-induced redox processes generate the observed toxicity. PMID:26287162

  7. Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes

    Directory of Open Access Journals (Sweden)

    Khachatur Julfakyan

    2015-08-01

    Full Text Available Polydopamine-coated FeCo nanocubes (PDFCs were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm2 power. These particles were found to be non-toxic in the absence of irradiation, but gained significant toxicity upon irradiation. Interestingly, no increase in relative heating rate was observed when the PDFCs were irradiated in solution, eliminating nanoparticle (NP-induced thermal ablation as the source of toxicity. Based on these studies, we propose that microwave-induced redox processes generate the observed toxicity.

  8. Spherical microwave confinement and ball lightning

    Science.gov (United States)

    Robinson, William Richard

    This dissertation presents the results of research done on unconventional energy technologies from 1995 to 2009. The present civilization depends on an infrastructure that was constructed and is maintained almost entirely using concentrated fuels and ores, both of which will run out. Diffuse renewable energy sources rely on this same infrastructure, and hence face the same limitations. I first examined sonoluminescence directed toward fusion, but demonstrated theoretically that this is impossible. I next studied Low Energy Nuclear Reactions and developed methods for improving results, although these have not been implemented. In 2000, I began Spherical Microwave Confinement (SMC), which confines and heats plasma with microwaves in a spherical chamber. The reactor was designed and built to provide the data needed to investigate the possibility of achieving fusion conditions with microwave confinement. A second objective was to attempt to create ball lightning (BL). The reactor featured 20 magnetrons, which were driven by a capacitor bank and operated in a 0.2 s pulse mode at 2.45 GHz. These provided 20 kW to an icosahedral array of 20 antennas. Video of plasmas led to a redesign of the antennas to provide better coupling of the microwaves to the plasma. A second improvement was a grid at the base of the antennas, which provided corona electrons and an electric field to aid quick formation of plasmas. Although fusion conditions were never achieved and ball lightning not observed, experience gained from operating this basic, affordable system has been incorporated in a more sophisticated reactor design intended for future research. This would use magnets that were originally planned. The cusp geometry of the magnetic fields is suitable for electron cyclotron resonance in the same type of closed surface that in existing reactors has generated high-temperature plasmas. Should ball lightning be created, it could be a practical power source with nearly ideal

  9. Inspiring the next generation of scientists with their observations of quasars, black holes, Jupiter, and SETI with the Goldstone Apple Valley Radio Telescope, GAVRT

    Science.gov (United States)

    Jauncey, D. L.; Levin, S.; Teitelbaum, L.; Hofstadter, M.; Arballo, J.; McConnell, S.; Dorcey, R.; Cole, K.; Kreuser-Jenkins, N.; Leflang, J.; Kruzins, E.; Ricardo, L.; Horiuchi, S.; Nagle, G.; Miro, C. G.

    2017-04-01

    This paper describes a radio astronomy programfor schools, the Goldstone-AppleValley Radio Telescope,GAVRT. The GAVRT program is designed to bring the inspiration and enthusiasm to a younger generation of teachers and children who learn about science by doing real science, just as Iosif Shklovsky brought to an older generation.

  10. Fast microwave assisted pyrolysis of biomass using microwave absorbent.

    Science.gov (United States)

    Borges, Fernanda Cabral; Du, Zhenyi; Xie, Qinglong; Trierweiler, Jorge Otávio; Cheng, Yanling; Wan, Yiqin; Liu, Yuhuan; Zhu, Rongbi; Lin, Xiangyang; Chen, Paul; Ruan, Roger

    2014-03-01

    A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480°C, 50 grit SiC, with 2g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490°C to 560°C, biomass particle sizes from 0.9mm to 1.9mm, and vacuum degree lower than 100mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Wide spectrum microwave pulse measurement

    Energy Technology Data Exchange (ETDEWEB)

    King, R.J.

    1986-01-01

    Various techniques are postulated as diagnostics for wide band microwave pulses. The diagnostics include determinations of both the instantaneous amplitude and the frequency content of one-shot pulses. 6 refs., 11 figs. (WRF)

  12. Scanning Microwave Induced Acoustic Tomography

    National Research Council Canada - National Science Library

    Wang, Lihong V

    2001-01-01

    .... Cancerous breast tissues are found to be 2-5 times more strongly absorbing than surrounding normal breast tissues in the microwave, which has been attributed to an increase in bound water and sodium...

  13. Processing of thermoset prepreg laminate via exposure to microwave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, F.L. [Oak Ridge National Lab., TN (United States); Meek, T.T. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering

    1994-06-01

    Studies of microwave-assisted curing of neat resins (epoxy) and unidirectional glass and carbon fiber laminates have shown that a substantial reduction in the curing time was obtained. This may be explained by the penetration of microwave energy directly and throughout the laminate with enhancement of the kinetics of the chemical reaction. Results of this work indicate that the microwave assisted curing of glass fiber laminates also shows a substantial reduction of the required curing time. Microwave radiation of 2.45 GHz has been demonstrated to be an acceptable method to cure unidirectional carbon fiber laminates. Also, effective curing of crossply (0/90) laminates through this method was observed when proper rotation of the parts accompanied the curing process. This is in accordance with previous work. Multidirectional carbon fiber/epoxy laminates demonstrate a lack of coupling during the curing process. A direct curing of these laminates was not possible by microwave radiation with the experimental approach used, in agreement with previous work. Nevertheless, a moderate reduction in the curing time of these thin laminates was observed due to hybrid curing.

  14. Microwave remote sensing from space

    OpenAIRE

    Carver, Keith R.; Elachi, Charles; Ulaby, Fawwaz T.

    1985-01-01

    Spaceborne microwave remote sensors provide perspectives of the earth surface and atmosphere which are of unique value in scientific studies of geomorphology, oceanic waves and topography, atmospheric water vapor and temperatures, vegetation classification and stress, ice types and dynamics, and hydrological characteristics. Microwave radars and radiometers offer enhanced sensitivities to the geometrical characteristics of the earth's surface and its cover, to water in all its forms--soil and...

  15. Microwave applications of soft ferrites

    CERN Document Server

    Pardavi-Horvath, M P

    2000-01-01

    Signal processing requires broadband, low-loss, low-cost microwave devices (circulators, isolators, phase shifters, absorbers). Soft ferrites (garnets, spinels, hexaferrites), applied in planar microwave devices, are reviewed from the point of view of device requirements. Magnetic properties, specific to operation in high-frequency electromagnetic fields, are discussed. Recent developments in thick film ferrite technology and device design are reviewed. Magnetic losses related to planar shape and inhomogeneous internal fields are analyzed.

  16. Acute low-level microwave exposure and central cholinergic activity: studies on irradiation parameters

    Energy Technology Data Exchange (ETDEWEB)

    Lai, H.; Horita, A.; Guy, A.W.

    1988-01-01

    Sodium-dependent high-affinity choline uptake was measured in the striatum, frontal cortex, hippocampus, and hypothalamus of rats after acute exposure (45 min) to pulsed (2 microseconds, 500 pps) or continuous-wave 2,450-MHz microwaves in cylindrical waveguides or miniature anechoic chambers. In all exposure conditions, the average whole-body specific absorption rate was at 0.6 W/kg. Decrease in choline uptake was observed in the frontal cortex after microwave exposure in all of the above irradiation conditions. Regardless of the exposure system used, hippocampal choline uptake was decreased after exposure to pulsed but not continuous-wave microwaves. Striatal choline uptake was decreased after exposure to either pulsed or continuous-wave microwaves in the miniature anechoic chamber. No significant change in hypothalamic choline uptake was observed under any of the exposure conditions studied. We conclude that depending on the parameters of the radiation, microwaves can elicit specific and generalized biological effects.

  17. First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers.

    Science.gov (United States)

    Smída, R; Werner, F; Engel, R; Arteaga-Velázquez, J C; Bekk, K; Bertaina, M; Blümer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Cossavella, F; Di Pierro, F; Doll, P; Fuchs, B; Fuhrmann, D; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Huber, D; Huege, T; Kampert, K-H; Kang, D; Klages, H; Kleifges, M; Krömer, O; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Mathys, S; Mayer, H J; Melissas, M; Morello, C; Neunteufel, P; Oehlschläger, J; Palmieri, N; Pekala, J; Pierog, T; Rautenberg, J; Rebel, H; Riegel, M; Roth, M; Salamida, F; Schieler, H; Schoo, S; Schröder, F G; Sima, O; Stasielak, J; Toma, G; Trinchero, G C; Unger, M; Weber, M; Weindl, A; Wilczyński, H; Will, M; Wochele, J; Zabierowski, J

    2014-11-28

    We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16}  eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17}  eV.

  18. Global relation between microwave satellite vegetation products and vegetation productivity

    Science.gov (United States)

    Teubner, Irene E.; Forkel, Matthias; Jung, Martin; Miralles, Diego G.; Dorigo, Wouter A.

    2017-04-01

    The occurrence of unfavourable environmental conditions like droughts commonly reduces the photosynthetic activity of ecosystems and, hence, their potential to take up carbon from the atmosphere. Ecosystem photosynthetic activity is commonly determined using remote sensing observations in the optical domain, which however have limitations particularly in regions of frequent cloud cover, e.g. the tropics. In this study, we explore the potential of vegetation optical depth (VOD) from microwave satellite observations as an alternative source for assessing vegetation productivity. VOD serves as an estimate for vegetation density and water content, which has an impact on plant physiological processes and hence should potentially provide a link to gross primary production (GPP). However, to date, it is unclear how microwave-retrieved VOD data and GPP data are related. We compare seasonal dynamics and anomalies of VOD retrievals from different satellite sensors and microwave frequencies with site level and global GPP estimates. We use VOD observations from active (ASCAT) and passive microwave sensors (AMSR-E, SMOS). We include eddy covariance measurements from the FLUXNET2015 dataset to assess the VOD products at site level. For a global scale analysis, we use the solar-induced chlorophyll fluorescence (SIF) observations from GOME-2 as a proxy for GPP and the FLUXCOM GPP product, which presents an upscaling of site measurements based on remote sensing data. Our results demonstrate that in general a good agreement between VOD and GPP or SIF exists. However, the strength of these relations depends on the microwave frequency, land cover type, and the time within the growing season. Correlations between anomalies of VOD and GPP or SIF support the assumption that microwave-derived VOD can be used to monitor vegetation productivity dynamics. The study is performed as part of the EOWAVE project funded by the Vienna University of Technology (http://eowave.geo.tuwien.ac.at/) and

  19. Microwave remote sensing from space

    Science.gov (United States)

    Carver, K. R.; Elachi, C.; Ulaby, F. T.

    1985-01-01

    Spaceborne microwave remote sensors provide perspectives of the earth surface and atmosphere which are of unique value in scientific studies of geomorphology, oceanic waves and topography, atmospheric water vapor and temperatures, vegetation classification and stress, ice types and dynamics, and hydrological characteristics. Microwave radars and radiometers offer enhanced sensitivities to the geometrical characteristics of the earth's surface and its cover, to water in all its forms - soil and vegetation moisture, ice, wetlands, oceans, and atmospheric water vapor, and can provide high-resolution imagery of the earth's surface independent of cloud cover or sun angle. A brief review of the historical development and principles of active and passive microwave remote sensing is presented, with emphasis on the unique characteristics of the information obtainable in the microwave spectrum and the value of this information to global geoscientific studies. Various spaceborne microwave remote sensors are described, with applications to geology, planetology, oceanography, glaciology, land biology, meteorology, and hydrology. A discussion of future microwave remote sensor technological developments and challenges is presented, along with a summary of future missions being planned by several countries.

  20. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  1. Microwave Drying of Moist Coals

    Science.gov (United States)

    Salomatov, Vl. V.; Karelin, V. A.; Sladkov, S. O.; Salomatov, Vas. V.

    2017-03-01

    Physical principles and examples of practical implementation of drying large bodies of coal by microwave radiation are considered. It is shown that energy consumption in microwave drying of brown coals decreases to 1.5-1.8 (kW·h)/ kg as compared with traditional types of drying, for which the expenditures of energy amount to 3.0 (kW·h)/kg. In using microwave drying, the technological time of drying decreases to 4 h, whereas the time of convective drying, with other things being equal, comes to 8-20 h. Parallel with microwave radiation drying, grinding of a fuel takes place, as well as entrainment of such toxic and ecologically harmful elements as mercury, chlorine, phosphorus, sulfur, and nitrogen. An analysis of the prospects of using a microwave energy for drying coal fuel has shown that microwave radiation makes it possible to considerably economize in energy, increase explosional safety, improve the ecological situation, and reduce the metal content and overall dimensions of the equipment.

  2. Study of federal microwave standards

    Energy Technology Data Exchange (ETDEWEB)

    David, L.

    1980-08-01

    Present and future federal regulatory processes which may impact the permissible levels of microwave radiation emitted by the SPS Microwave Power Transmission (MPTS) were studied. An historical development of US occupational and public microwave standards includes an overview of Western and East European philosophies of environmental protection and neurophysiology which have led to the current widely differing maximum permissible exposure limits to microwaves. The possible convergence of microwave standards is characterized by a lowering of Western exposure levels while Eastern countries consider standard relaxation. A trend toward stricter controls on activities perceived as harmful to public health is under way as is interest in improving the federal regulatory process. Particularly relevant to SPS is the initiation of long-term, low-level microwave exposure programs. Coupled with new developments in instrumentation and dosimetry, the results from chronic exposure program and population exposure studies could be expected within the next five to ten years. Also discussed is the increasing public concern that rf energy is yet another hazardous environmental agent.

  3. Observational constraints on extended Chaplygin gas cosmologies

    Indian Academy of Sciences (India)

    B C Paul

    2017-07-24

    ECG) as a candidate for dark energy and determine the equation of state parameters using observed data namely, observed Hubble data, baryon acoustic oscillation data and cosmic microwave background shift data.

  4. Isothermal Reactor for Continuous Flow Microwave-Assisted Chemical Reaction

    Science.gov (United States)

    Matsuzawa, Mitsuhiro; Togashi, Shigenori; Hasebe, Shinji

    An isothermal reactor in which reaction solutions can be controlled at constant temperature under constant microwave irradiation was developed. This is useful for investigating microwave effects on chemical reactions that are not observed under conventional heating conditions. We devised a structure in which a heat-transfer medium with a low dielectric loss factor, which hardly absorbs any microwaves, flowed outside a spiral reaction tube and designed the basic structure of the reactor using electromagnetic simulation to optimize the energy absorption rate. The conditions for increasing the temperature controlling ability of the reactor were also investigated theoretically and experimentally by taking into consideration the influences of three elements: the velocity of the internal fluid, the material for the tube, and the velocity of the external fluid. The velocity of the external fluid had the greatest influence on temperature controlling ability and the material for the tube had the least influence under the experimental conditions. The overall heat transfer coefficient was about 3.9×102 W/(m2·K) when water flowed through the quartz reaction tube at 7.1 mm/s and the external fluid flowed outside the tube at 44 mm/s. We also tested and confirmed that the temperature of water used as internal fluid could be controlled to within ±1.5 K at 309.3 K when microwaves at 26 W were irradiated into the reactor, whereas the temperature of water was over 373 K and boiled without the heat-transfer medium flowing outside the reaction tube using a conventional method of microwave heating. In addition, we investigated microwave effects on Suzuki-Miyaura coupling reaction using the developed isothermal reactor and we confirmed that the temperatures were controlled well in the reactor. The yields obtained by microwave heating were almost the same as that obtained by oil-bath heating.

  5. Enhancing natural product extraction and mass transfer using selective microwave heating

    OpenAIRE

    Lee, Chai Siah; Binner, Eleanor; Winkworth-Smith, Charles; John, Rebecca; Gomes, R.L.; Robinson, John

    2016-01-01

    This study uses a combination of empirical observations and an analysis of mass transfer behaviour to yield new insights into the mechanism of microwave assisted extraction. Enhancements in extraction rate and yield were observed experimentally compared with conventional extraction at temperatures in excess of 50°C, however at lower temperatures there was no observable difference between the two processes. A step-change in extract yield between microwave and conventional processes was shown t...

  6. Microwave Sterilization and Depyrogenation System

    Science.gov (United States)

    Akse, James R.; Dahl, Roger W.; Wheeler, Richard R., Jr.

    2009-01-01

    A fully functional, microgravity-compatible microwave sterilization and depyrogenation system (MSDS) prototype was developed that is capable of producing medical-grade water (MGW) without expendable supplies, using NASA potable water that currently is available aboard the International Space Station (ISS) and will be available for Lunar and planetary missions in the future. The microwave- based, continuous MSDS efficiently couples microwaves to a single-phase, pressurized, flowing water stream that is rapidly heated above 150 C. Under these conditions, water is rapidly sterilized. Endotoxins, significant biological toxins that originate from the cell walls of gram-negative bacteria and which represent another defining MGW requirement, are also deactivated (i.e., depyrogenated) albeit more slowly, with such deactivation representing a more difficult challenge than sterilization. Several innovations culminated in the successful MSDS prototype design. The most significant is the antenna-directed microwave heating of a water stream flowing through a microwave sterilization chamber (MSC). Novel antenna designs were developed to increase microwave transmission efficiency. These improvements resulted in greater than 95-percent absorption of incident microwaves. In addition, incorporation of recuperative heat exchangers (RHxs) in the design reduced the microwave power required to heat a water stream flowing at 15 mL/min to 170 C to only 50 W. Further improvements in energy efficiency involved the employment of a second antenna to redirect reflected microwaves back into the MSC, eliminating the need for a water load and simplifying MSDS design. A quick connect (QC) is another innovation that can be sterilized and depyrogenated at temperature, and then cooled using a unique flow design, allowing collection of MGW at atmospheric pressure and 80 C. The final innovation was the use of in-line mixers incorporated in the flow path to disrupt laminar flow and increase contact time

  7. Linear and nonlinear microwave responses of a microwave photonic filter based on a photonic crystal microcavity

    Science.gov (United States)

    Long, Yun; Zhang, Yong; Zhang, Xinliang; Xia, Jinsong; Dong, Jianji; Wang, Jian

    2017-06-01

    We propose and demonstrate an ultracompact bandpass microwave photonic filter (MPF) based on a silicon photonic crystal (PhC) microcavity. Taking the fabricated PhC microcavity as an example, we comprehensively investigate both the linear and nonlinear microwave responses of the MPF based on silicon waveguide devices. Two cases are discussed in the experiment, i.e., the optical carrier wavelength is located on the left or right side of the notch resonant wavelength of the PhC microcavity. The experimental results agree well with the theoretical analyses. For the former case, the central frequency of MPF increases monotonically when fixing the optical carrier wavelength and increasing the optical carrier power. For the latter case, the nonlinear response at a fixed optical carrier wavelength shows a decrease first and then an increase in the central frequency of MPF when increasing the optical carrier power. A jump of the response is observed in the switching process. Moreover, we also observe an interesting bistable microwave response in the experiment under an optical carrier power of around -2.6 dBm in the latter case.

  8. Microwave energy attenuators on the basis of aluminum nitride with high level of microwave energy absorption

    Directory of Open Access Journals (Sweden)

    Chasnyk V. I.

    2014-08-01

    Full Text Available Results of experimental studies of aluminum nitride based composites with addition of silicon carbide and molybdenum having high microwave absorption are presented. The interconnection between high level of absorption and volume electrical resistance was observed: maximum absorption of 6.5±1,0 dB/mm corresponds to the electrical resistance of (4—5·105 Ohm·m. Level of absorption of 3.5±0,5 dB/mm is revealed for the dielectric material with electrical conductivity of 1012 Ohm·m. The patterns detected during the study allow to predict the minimum and maximum levels of absorption of microwave energy in the two-phase composites based on aluminum nitride with molybdenum or silicon carbide, based on the measured volume of electrical resistance.

  9. Microwave generation of stable atmospheric-pressure fireballs in air

    Science.gov (United States)

    Stephan, Karl D.

    2006-11-01

    The generation of stable buoyant fireballs in a microwave cavity in air at atmospheric pressure without the use of vaporized solids is described. These fireballs have some of the characteristics of ball lightning and resemble those reported by Dikhtyar and Jerby [Phys. Rev. Lett. 96, 045002 (2006)], although of a different color, and do not require the presence of molten or vaporized material. Mechanisms of microwave plasma formation and fluid dynamics can account for the observed behavior of the fireballs, which do not appear to meet the accepted definition of dusty plasmas in this case. Relevance to models of ball lightning and industrial applications are discussed.

  10. The Cosmic Microwave Background in the Light of Planck

    Energy Technology Data Exchange (ETDEWEB)

    Bernardis, P. dd; Calvo, M.; Giordano, C.; Masi, S.; Nati, F.; Piacentini, F.; Polenta, G. [Dipartimento di Fisica, Universita di Roma La Sapienza, and INFN Sezione di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2009-03-15

    The Cosmic Microwave Background (CMB) represents a window on the early universe, and allows observers to test cosmological models and fundamental physics, including neutrino physics. Ground-based, balloon-borne and satellite experiments in the last decade have provided sensitive measurements of the CMB, precision estimates of the cosmological parameters, and strong constraints on neutrino properties. The forthcoming Planck mission of the European Space Agency will provide definitive measurements of the CMB and will allow a clean, unambiguous separation of foreground and background microwave emission. Here we summarize the most recent results and discuss new perspectives in this field and their impact on cosmology and fundamental physics.

  11. Synthesis of nanosized silver colloids by microwave dielectric heating

    Indian Academy of Sciences (India)

    Silver nanosized crystallites have been synthesized in aqueous and polyols viz., ethylene glycol and glycerol, using a microwave technique. Dispersions of colloidal silver have been prepared by the reduction of silver nitrate both in the presence and absence of stabilizer poly(vinylpyrolidone) (PVP). It was observed that ...

  12. Cyclotron Resonance of Electrons Trapped in a Microwave Cavity

    Science.gov (United States)

    Elmore, W. C.

    1975-01-01

    Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)

  13. The cosmic microwave background - A probe of particle physics

    Science.gov (United States)

    Silk, Joseph

    1990-01-01

    The current status of spectral distortions and angular anisotropies in the cosmic microwave background is reviewed, with emphasis on the role played by weakly interacting particle dark matter. Theoretical predictions and recent observational results are described, and prospects for future progress are summarized.

  14. Benchmarking Microwave Cavity Dark Matter Searches using a Radioactive Source

    CERN Multimedia

    Caspers, F

    2014-01-01

    A radioactive source is proposed as a calibration device to verify the sensitivity of a microwave dark matter search experiment. The interaction of e.g., electrons travelling in an arbitrary direction and velocity through an electromagnetically “empty” microwave cavity can be calculated numerically. We give an estimation of the energy deposited by a charged particle into a particular mode. Numerical examples are given for beta emitters and two particular cases: interaction with a field free cavity and interaction with a cavity which already contains an electromagnetic field. Each particle delivers a certain amount of energy related to the modal R/Q value of the cavity. The transferred energy is a function of the particles trajectory and its velocity. It results in a resonant response of the cavity, which can be observed using a sensitive microwave receiver, provided that the deposited energy is significantly above the single photon threshold.

  15. Microwave-assisted Weak Acid Hydrolysis of Proteins

    Directory of Open Access Journals (Sweden)

    Miyeong Seo

    2012-06-01

    Full Text Available Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at 37 oC, 50 oC, and100 oC for 1 h. The most effective hydrolysis was observed at 100 oC. Hydrolysis products were investigated using matrixassistedlaser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini ofaspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60-min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at100 oC. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteinsand that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.

  16. Degradation of phenol under combined irradiation of microwaves and ultrasound.

    Science.gov (United States)

    Wu, Zhi-Lin; Ondruschka, Bernd; Cravotto, Giancarlo

    2008-11-01

    A novel combined system of irradiation by microwaves and ultrasound is used to efficiently destroy phenol in aqueous solutions via sono-generated hydroxyl radicals and H2O2, in conjunction with the rapid thermal effect of microwaves on polar chemicals. Microwave irradiation enhances the sono-degradation of phenol without any additional catalyst although the effect is more marked when H2O2 is added. The degradation of phenol by MW or US alone or by combined irradiation of MW-US follows zero order kinetics. Degradation rate constants and yields of the main intermediates, catechol and hydroquinone, follow the order of MW-US > MW > US. The degradation rate also increases with higher reaction temperature in the MW reactor. The synergistic effects of MW and US were observed at 93 degrees C without addition of H2O2 and at 60 degrees C with addition of H2O2.

  17. Devulcanization of styrene butadiene rubber by microwave energy: Effect of the presence of ionic liquid

    Directory of Open Access Journals (Sweden)

    S. Seghar

    2015-12-01

    Full Text Available In this study, styrene butadiene rubber (SBR was devulcanized using microwave irradiation. In particular, effect of ionic liquid (IL, pyrrolidinium hydrogen sulfate [Pyrr][HSO4], on the devulcanization performance was studied. It was observed that the evolution of the temperature reached by rubber powder exposed to microwave irradiation for different energy values was favored by the presence of ionic liquid [Pyrr][HSO4] significantly over the whole range of the microwave energy values. Beyond the threshold point of 220 Wh/kg, the soluble fraction after devulcanization sharply increased with increasing devulcanization microwave energy. For the powder mixed with [Pyrr][HSO4], the increase was more significant. Furthermore, the crosslink density was observed to decrease slowly with the microwave energy up to 220 Wh/kg, beyond which the crosslink density decreased significantly for the rubber impregnated with IL. For the rubber with IL, significant and continuous increase in Tg with microwave energy values was observed in comparison with the SBR where no change in transition temperature was observed. Mechanical shearing of rubber gums in the two-roll mill favored the devulcanization process, which indicated that the combination of mechanical loading with microwave energy and IL is an efficient procedure allowing an optimal devulcanization of rubbers.

  18. Model Stirrer Based on a Multi-Material Turntable for Microwave Processing Materials

    Science.gov (United States)

    Ye, Jinghua; Hong, Tao; Wu, Yuanyuan; Wu, Li; Liao, Yinhong; Zhu, Huacheng; Yang, Yang; Huang, Kama

    2017-01-01

    Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE) and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation. During the heating process, the processed material is placed on a fixed Teflon bracket which covers the constantly rotating turntable. Experiments are conducted to measure the surface and point temperatures using an infrared thermal imaging camera and optical fibers. Simulated results are compared qualitatively with the measured ones, which verifies the simulated models. Compared with the turntables consisting of a single material, a 26%–47% increase in temperature uniformity from adapting the multi-material turntable can be observed for the microwave-processed materials. PMID:28772457

  19. Botswana water and surface energy balance research program. Part 2: Large scale moisture and passive microwaves

    Science.gov (United States)

    Vandegriend, A. A.; Owe, M.; Chang, A. T. C.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. The research program consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components are explained in general and activities performed within the passive microwave research component are summarized. The microwave theory is discussed taking into account: soil dielectric constant, emissivity, soil roughness effects, vegetation effects, optical depth, single scattering albedo, and wavelength effects. The study site is described. The soil moisture data and its processing are considered. The relation between observed large scale soil moisture and normalized brightness temperatures is discussed. Vegetation characteristics and inverse modeling of soil emissivity is considered.

  20. Microwave diagnostics of atmospheric plasmas

    Science.gov (United States)

    Scott, David

    Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon

  1. Microwave Plasma System: PVA Tepla 300

    Data.gov (United States)

    Federal Laboratory Consortium — Description:CORAL Name: Microwave AsherA tool using microwave oxygen plasma to remove organics on the surfacesSpecifications / Capabilities:Frequency: 2.45 GHzPower:...

  2. Student Microwave Experiments Involving the Doppler Effect.

    Science.gov (United States)

    Weber, F. Neff; And Others

    1980-01-01

    Described is the use of the Doppler Effect with microwaves in the measurement of the acceleration due to gravity of falling objects. The experiments described add to the repertoire of quantitative student microwave experiments. (Author/DS)

  3. DMSP SSM/I- Microwave Imager

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/I is a seven-channel, four frequency, linearly-polarized, passive microwave radiometric system which measures atmospheric, ocean and terrain microwave...

  4. Silicon on insulator bipolar junction transistors for flexible microwave applications

    Science.gov (United States)

    Bavier, John McGoldrick

    Microwave frequency flexible electronic devices require a high quality semiconducting material and a set of fabrication techniques that are compatible with device integration onto flexible polymer substrates. Over the past ten years, monocrystalline silicon nanomembranes (SiNMs) have been studied as a flexible semiconducting material that is compatible with industrial Si processing. Fabricated from commercial silicon on insulator (SOI) wafers, SiNMs can be transferred to flexible substrates using a variety of techniques. Due to their high carrier mobilities, SiNMs are a promising candidate for flexible microwave frequency devices. This dissertation presents fabrication techniques for flexible SiNM devices in general, as well as the progress made towards the development of a microwave frequency SiNM bipolar junction transistor (BJT). In order to overcome previous limitations associated with adhesion, novel methods for transfer printing of metal films and SiNMs are presented. These techniques enable transfer printing of a range of metal films and improve the alignment of small transfer printed SiNM devices. Work towards the development of a microwave frequency BJT on SOI for SiNM devices is also described. Utilizing a self-aligned polysilicon sidewall spacer technique, a BJT with an ultra-narrow base region is fabricated and tested. Two regimes of operation are identified and characterized under DC conditions. At low base currents, devices exhibited forward current gain as high as betaF = 900. At higher base current values, a transconductance of 59 mS was observed. Microwave scattering parameters were obtained for the BJTs under both biasing conditions and compared to unbiased measurements. Microwave frequency gain was not observed. Instead, bias-dependent non-reciprocal behavior was observed and examined. Limitations associated with the microwave impedance-matched electrode configuration are presented. High current densities in the narrow electrodes cause localized

  5. Digital microwave communication engineering point-to-point microwave systems

    CERN Document Server

    Kizer, George

    2013-01-01

    The first book to cover all engineering aspects of microwave communication path design for the digital age Fixed point-to-point microwave systems provide moderate-capacity digital transmission between well-defined locations. Most popular in situations where fiber optics or satellite communication is impractical, it is commonly used for cellular or PCS site interconnectivity where digital connectivity is needed but not economically available from other sources, and in private networks where reliability is most important. Until now, no book has adequately treated all en

  6. CLPX-Ground: University of Michigan Ground-Based Microwave Radiometer, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains microwave radiometry data collected at the Local Scale Observation Site (LSOS) of the Cold Land Processes Field Experiment (CLPX) in Colorado,...

  7. CLPX-Ground: University of Michigan Ground-Based Microwave Radiometer

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains microwave radiometry data collected at the Local Scale Observation Site (LSOS) of the Cold Land Processes Field Experiment (CLPX) in Colorado,...

  8. Optimizing Performance of a Microwave Salinity Mapper: STARRS L-Band Radiometer Enhancements

    National Research Council Canada - National Science Library

    Burrage, Derek M; Wesson, Joel C; Goodberlet, Mark A; Miller, Jerry L

    2007-01-01

    Airborne microwave radiometers for salinity remote sensing have advanced to a point where operational surveys can be conducted over the inner continental shelf to observe the evolution of freshwater...

  9. Microwave studies of planetary atmospheres. [by Mariner 2 Space Probe for Jupiter and Venus

    Science.gov (United States)

    Jones, D. E.

    1975-01-01

    Data from microwave observations of the atmospheres of Jupiter and Venus are examined. Radar features with corresponding coordinates of longitude and lattitude are given, along with scans of Mariner 2 radiometer beams.

  10. At what wavelengths should we search for signals from extraterrestrial intelligence? (SETI/infrared communication/interstellar communication/extraterrestrial intelligence)

    Science.gov (United States)

    Townes, C. H.

    1979-01-01

    Searches for extraterrestrial intelligence concentrate on attempts to receive signals in the microwave region, the argument being given that communication occurs there at minimum broadcasted power. Such a conclusion is shown to result only under a restricted set of assumptions. If generalized types of detection are considered, in particular photon detection rather than linear detection alone, and if advantage is taken of the directivity of telescopes at short wavelengths, then somewhat less power is required for communication at infrared wavelengths than in the microwave region. Furthermore, a variety of parameters other than power alone can be chosen for optimization by an extraterrestrial civilization.

  11. Compact Microwave Fourier Spectrum Analyzer

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

    2009-01-01

    A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

  12. 21 CFR 1030.10 - Microwave ovens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Microwave ovens. 1030.10 Section 1030.10 Food and... ovens. (a) Applicability. The provisions of this standard are applicable to microwave ovens manufactured after October 6, 1971. (b) Definitions. (1) Microwave oven means a device designed to heat, cook, or dry...

  13. Mechanical characterization of microwave sintered zinc oxide

    Indian Academy of Sciences (India)

    The mechanical characterization of microwave sintered zinc oxide disks is reported. The microwave sintering was done with a specially designed applicator placed in a domestic microwave oven operating at a frequency of 2.45 GHz to a maximum power output of 800 Watt. These samples with a wide variation of density ...

  14. 47 CFR 101.141 - Microwave modulation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Microwave modulation. 101.141 Section 101.141... SERVICES Technical Standards § 101.141 Microwave modulation. (a) Microwave transmitters employing digital modulation techniques and operating below 25.25 GHz (except for MVDDS stations in the 12,200-12,700 MHz band...

  15. Microwave synthesis and mechanical characterization of functionally ...

    Indian Academy of Sciences (India)

    Skin depth of electromagnetic radiation increases with tem- perature and consequently material–microwave interaction increases with temperature. At high temperatures, efficient penetration of microwaves provides sufficient volume for material–microwave interaction and hence substantial vol- umetric heating of metal ...

  16. Project META (Microwave Energy Transmission for Aircraft)

    Science.gov (United States)

    2009-09-01

    viability of using microwave energy transmission technology to power air vehicles remotely was investigated. On-board antennas ( rectennas ) harvest... rectenna to receive microwave energy and convert it to usable DC power. A prototype was designed and experimentally tested under controlled...beamed energy, beaming energy, remotely powered aircraft, rectenna , microwave propulsion 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  17. Influence of Internal Temperatures of Soil on Soil Drying Curves by the Microwave Heating

    OpenAIRE

    UEDA, Kazuo

    1995-01-01

    The development of the method of quick determination of water content by microwaves has being watched with keenest interest by soil mechanics and foundation engineers. A certain number of experimental works have made it clear that the microwave oven functions well for the present compared to JIS method. In detailed observation, usually it was observed in a conventional oven that soil sample with low wet density required shorter than the time for drying of the one with high wet density. But, d...

  18. Microwave materials for wireless applications

    CERN Document Server

    Cruickshank, David B

    2011-01-01

    This practical resource offers you an in-depth, up-to-date understanding of the use of microwave magnetic materials for cutting-edge wireless applications. The book discusses device applications used in wireless infrastructure base stations, point-to-point radio links, and a range of more specialized microwave systems. You find detailed discussions on the attributes of each family of magnetic materials with respect to specific wireless applications. Moreover, the book addresses two of the hottest topics in the field today - insertion loss and intermodulation. This comprehensive reference also

  19. Microwave vegetation indices derived from satellite microwave radiometers

    Science.gov (United States)

    Vegetation indices are valuable in many fields of geosciences. Conventional, visible-near infrared, indices are often limited by the effects of atmosphere, background soil conditions, and saturation at high levels of vegetation. In this study, the theoretical basis for a new type of passive microwav...

  20. Recent Advancements in Microwave Imaging Plasma Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    H. Park; C.C. Chang; B.H. Deng; C.W. Domier; A.J.H. Donni; K. Kawahata; C. Liang; X.P. Liang; H.J. Lu; N.C. Luhmann, Jr.; A. Mase; H. Matsuura; E. Mazzucato; A. Miura; K. Mizuno; T. Munsat; K. and Y. Nagayama; M.J. van de Pol; J. Wang; Z.G. Xia; W-K. Zhang

    2002-03-26

    Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are revolutionary microwave electron cyclotron emission imaging (ECEI), microwave phase imaging interferometers, imaging microwave scattering and microwave imaging reflectometer (MIR) systems for imaging electron temperature and electron density fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori, and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.

  1. All-Sky Microwave Imager Data Assimilation at NASA GMAO

    Science.gov (United States)

    Kim, Min-Jeong; Jin, Jianjun; El Akkraoui, Amal; McCarty, Will; Todling, Ricardo; Gu, Wei; Gelaro, Ron

    2017-01-01

    Efforts in all-sky satellite data assimilation at the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center have been focused on the development of GSI configurations to assimilate all-sky data from microwave imagers such as the GPM Microwave Imager (GMI) and Global Change Observation Mission-Water (GCOM-W) Advanced Microwave Scanning Radiometer 2 (AMSR-2). Electromagnetic characteristics associated with their wavelengths allow microwave imager data to be relatively transparent to atmospheric gases and thin ice clouds, and highly sensitive to precipitation. Therefore, GMAOs all-sky data assimilation efforts are primarily focused on utilizing these data in precipitating regions. The all-sky framework being tested at GMAO employs the GSI in a hybrid 4D-EnVar configuration of the Goddard Earth Observing System (GEOS) data assimilation system, which will be included in the next formal update of GEOS. This article provides an overview of the development of all-sky radiance assimilation in GEOS, including some performance metrics. In addition, various projects underway at GMAO designed to enhance the all-sky implementation will be introduced.

  2. Topological magnetoelectric effects in microwave far-field radiation

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, M.; Kamenetskii, E. O.; Shavit, R. [Microwave Magnetic Laboratory, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2016-07-21

    Similar to electromagnetism, described by the Maxwell equations, the physics of magnetoelectric (ME) phenomena deals with the fundamental problem of the relationship between electric and magnetic fields. Despite a formal resemblance between the two notions, they concern effects of different natures. In general, ME-coupling effects manifest in numerous macroscopic phenomena in solids with space and time symmetry breakings. Recently, it was shown that the near fields in the proximity of a small ferrite particle with magnetic-dipolar-mode (MDM) oscillations have the space and time symmetry breakings and the topological properties of these fields are different from the topological properties of the free-space electromagnetic fields. Such MDM-originated fields—called magnetoelectric (ME) fields—carry both spin and orbital angular momenta. They are characterized by power-flow vortices and non-zero helicity. In this paper, we report on observation of the topological ME effects in far-field microwave radiation based on a small microwave antenna with a MDM ferrite resonator. We show that the microwave far-field radiation can be manifested with a torsion structure where an angle between the electric and magnetic field vectors varies. We discuss the question on observation of the regions of localized ME energy in far-field microwave radiation.

  3. Anomalous non-resonant microwave absorption in SmFeAs(O,F) polycrystalline sample

    Energy Technology Data Exchange (ETDEWEB)

    Onyancha, R.B., E-mail: 08muma@gmail.com [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg, 1710 (South Africa); Shimoyama, J. [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Singh, S.J. [Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, D-01171 Dresden (Germany); Hayashi, K.; Ogino, H. [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Srinivasu, V.V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg, 1710 (South Africa)

    2017-02-15

    Highlights: • The non-resonant microwave absorption (NRMA) line shape in evolved with microwave power. • Observed a cross over from ‘normal’ absorption to ‘anomalous’ absorption as a function of microwave power. • The anomalous absorption has been explained in the context of non-hysteretic Josephson junction. - Abstract: Here we present the non-resonant microwave absorption (NRMA) studies on SmFeAsO{sub 0.88}F{sub 0.12} polycrystalline sample measured at 6.06 K with the magnetic field swept from −250 G to +250 G at a frequency of 9.45 GHz. It was observed that the (NRMA) line shape evolves as a function of microwave power. Again, the signal intensity increases from 22.83 µW to 0.710 mW where it reaches a maximum and quite remarkably it changed from ‘normal’ absorption to ‘anomalous’ absorption at 2.247 mW, then the intensity decreases with further increase of microwave power. The crossover from ‘normal’ to ‘anomalous’ NRMA absorption and its dependence on microwave power is a new phenomenon in iron pnictides superconductors and we have attributed this anomaly to come from non-hysteretic Josephson junction.

  4. Kinetic advantages of using microwaves in the emulsion polymerization of MMA

    Energy Technology Data Exchange (ETDEWEB)

    Costa, C. [Departamento de Engenharia Quimica, Universidade Federal de Santa Catarina, Campus Universitario, CEP: 88040-900, Florianopolis, SC (Brazil); Santos, A.F.; Fortuny, M. [Programa de Mestrado em Engenharia de Processos, Universidade Tiradentes, Instituto de Tecnologia e Pesquisa, Av. Murilo Dantas, 300, CEP: 49032-490, Aracaju, SE (Brazil); Araujo, P.H.H. [Departamento de Engenharia Quimica, Universidade Federal de Santa Catarina, Campus Universitario, CEP: 88040-900, Florianopolis, SC (Brazil); Sayer, C. [Departamento de Engenharia Quimica, Universidade Federal de Santa Catarina, Campus Universitario, CEP: 88040-900, Florianopolis, SC (Brazil)], E-mail: csayer@enq.ufsc.br

    2009-03-01

    Microwave irradiation has been an interesting alternative for heating systems and several chemical reactions. In polymerization processes, microwaves can enhance reaction rates or improve specific characteristics of the formed polymer. In this work, the use of microwave irradiation in emulsion polymerization reactions has been studied, using a commercial microwave reactor, which is able to perform syntheses under controlled conditions of temperature and power. Methyl methacrylate emulsion polymerization reactions were faster, resulting in smaller polymer particles, in comparison to the conventional heating method (reactions in a jacketed reactor). Different effects were observed in the emulsion polymerization of butyl acrylate. To study the effect of high power microwave irradiation upon the emulsion polymerization, a pulsed irradiation strategy was developed, in which the samples were repeatedly heated within short intervals of time (about 27 s) at the maximum microwave power. A significant reduction of the total time of irradiation was observed in reactions carried out under the pulsed scheme, showing the kinetic advantages of using microwaves in emulsion polymerization processes.

  5. Comparison of conventional and microwave histo-processing of various oral soft tissue specimens

    Directory of Open Access Journals (Sweden)

    Shankargouda Patil

    2014-01-01

    Full Text Available Background and Aim: While a number of pathologists have reviewed the techniques and results of microwave-facilitated tissue fixation and processing, there has been no record of any previous studies where specific tissues were chosen and compared. Hence, the aim of the present study was to specifically evaluate and compare the diagnostic ability of selective oral soft tissue specimens processed and stained by the conventional and microwave method. Materials and Methods: The study group comprised of 40 formalin-fixed tissue samples from the archives of the Department of Oral Pathology, 10 each of epithelial, muscle, adipose and glandular tissue. Each specimen was cut into two halves with one half processed and stained by the conventional method while the other by the microwave method. With the procedure blinded, four observers evaluated the slides employing Babu et al′s criteria pertaining to cellular clarity, cytoplasmic details, nuclear detail and color intensity. The results were statistically analyzed using Chi-square test and kappa. Results: The microwave method yielded better results as compared to the conventional with respect to processing and staining although there was no statistical difference between the two. A drastic reduction in time with the microwave method was observed. Conclusion: The results obtained by microwave method surpassed the conventional method. Hence, it is ideal to adopt the microwave method for any oral soft tissue for quicker and reliable results.

  6. Controlled zone microwave plasma system

    Science.gov (United States)

    Ripley, Edward B [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Morrell, Jonathan S [Knoxville, TN

    2009-10-20

    An apparatus and method for initiating a process gas plasma. A conductive plate having a plurality of conductive fingers is positioned in a microwave applicator. An arc forms between the conductive fingers to initiate the formation of a plasma. A transport mechanism may convey process materials through the plasma. A spray port may be provided to expel processed materials.

  7. Microwave Oven Repair. Teacher Edition.

    Science.gov (United States)

    Smreker, Eugene

    This competency-based curriculum guide for teachers addresses the skills a technician will need to service microwave ovens and to provide customer relations to help retain the customer's confidence in the product and trust in the service company that performs the repair. The guide begins with a task analysis, listing 20 cognitive tasks and 5…

  8. ULTRARAPID VACUUM-MICROWAVE HISTOPROCESSING

    NARCIS (Netherlands)

    KOK, LP; BOON, ME

    A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at

  9. Silicon nitride microwave photonic circuits

    NARCIS (Netherlands)

    Roeloffzen, C.G.H.; Zhuang, L.; Taddei, Caterina; Taddei, Caterina; Leinse, Arne; Heideman, Rene; van Dijk, Paulus W.L.; Oldenbeuving, Ruud; Marpaung, D.A.I.; Burla, M.; Buria, Maurizio; Boller, Klaus J.

    2013-01-01

    We present an overview of several microwave photonic processing functionalities based on combinations of Mach-Zehnder and ring resonator filters using the high index contrast silicon nitride (TriPleXTM) waveguide technology. All functionalities are built using the same basic building blocks, namely

  10. Microwave applicators for BPH thermotherapy

    Science.gov (United States)

    Vrba, Jan; Hlavac, R.; Herza, Jan; Chovanec, Roman; Cvek, Jakub; Oppl, L.

    2004-04-01

    Paper deals with new results in the field of intracavitary microwave applicators used for Benign Prostatic Hyperplasia (BPH) treatment. We demonstrate here that it is necessary to use more sophisticated applicators than a simple monopole radiating structure. One of the good possibilities for safe and efficient treatments we propose here is a helix structure.

  11. Microwave Treatment for Cardiac Arrhythmias

    Science.gov (United States)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  12. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc bias...

  13. Stable Targets for Spaceborne Microwave Radiometer Calibration

    Science.gov (United States)

    Njoku, Eni G.; Chan, S. K.; Armstrong, R. L.; Brodzik, M. J.; Savoie, M. H.; Knowles, K.

    2006-01-01

    Beginning in the 1970s, continuous observations of the Earth have been made by spaceborne microwave radiometers. Since these instruments have different observational characteristics, care must be taken in combining their data to form consistent long term records of brightness temperatures and derived geophysical quantities. To be useful for climate studies, data from different instruments must be calibrated relative to each other and to reference targets on the ground whose characteristics are stable and can be monitored continuously. Identifying such targets over land is not straightforward due to the heterogeneity and complexity of the land surface and cover. In this work, we provide an analysis of multi-sensor brightness temperature statistics over ocean, tropical forest, and ice sheet locations, spanning the period from 1978 to the present, and indicate the potential of these sites as continuous calibration monitoring targets.

  14. Application of Ground Based Microwave Radiometry for Characterizing Tropical Convection

    Science.gov (United States)

    Renju, R.; Raju, C. S.

    2016-12-01

    The characterization of the microphysical and thermodynamical properties of convective events over the tropical coastal station Thiruvananthapuram (TVM, 8.5o N 76.9oE) has been carried out by utilizing multiyear Microwave Radiometer Profiler (MRP) observations. The analyses have been extended to develop a methodology to identify convective events, based on the radiometric brightness temperature (Tb) differences, at 30 GHz and 22.5 GHz channels and are compared using reflectivity and rainfall intensity deduced from concurrent and collocated disdrometer measurements. In all 84 such convections were identified using the above methodology over the station for a period of years, 2010-2013; both during pre- and post- Indian summer monsoon months and further evaluated by computing their stability indices. The occurrence of convection over this coastal station peaks in the afternoon and early morning hours with genesis, respectively, over the land and the sea. The number of occurrence of convective events are less during monsoon deficit year whereas strong and more during heavy monsoon rainfall year. These findings are further evaluated with the percentage occurrence of fractional convective clouds derived from microwave payload SAPHIR observations on Megha-Tropique satellite. Based on the analyses the frequency of occurrence of convection can be related to the monsoonal rainfall obtaining over the region. The analyses also indicate that the microwave radiometric brightness temperature of humidity channels depicts the type of convection and respond two hours prior to the occurrence of rainfall. In addition to that the multi-angle observations of microwave radiometer profiler have been utilized to study the propagation of convective systems. This study and the methodology developed for identifying convection have significance in microwave (Ka- and W-band) satellite propagation characterization since convection and precipitation are the major hindrance to satellite

  15. Automotive Catalyst State Diagnosis Using Microwaves

    Directory of Open Access Journals (Sweden)

    Moos Ralf

    2015-01-01

    Full Text Available The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As “sensing” elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.

  16. Dynamic modes of microwave signal autogeneration in a radio photonic ring generator

    Science.gov (United States)

    Kondrashov, A. V.; Ustinov, A. B.; Kalinikos, B. A.

    2017-02-01

    Dynamic modes of microwave signal autogeneration in a radio photonic generator have been investigated. The generator is a ring circuit with a low-pass filter and microwave amplifier in its microwave path. The optical path contains an optical fiber delay line. The generator demonstrates the periodical, chaotic, and noise dynamics. It has been shown that the correlation dimensionality of the random signal attractor in the chaotic generation mode saturates with increasing phase space dimensionality. Saturation is not observed in the noise-generation mode.

  17. Microwave Magnetochiral Dichroism in the Chiral-Lattice Magnet Cu_{2}OSeO_{3}.

    Science.gov (United States)

    Okamura, Y; Kagawa, F; Seki, S; Kubota, M; Kawasaki, M; Tokura, Y

    2015-05-15

    Through broadband microwave spectroscopy in Faraday geometry, we observe distinct absorption spectra accompanying magnetoelectric (ME) resonance for oppositely propagating microwaves, i.e., directional dichroism, in the multiferroic chiral-lattice magnet Cu_{2}OSeO_{3}. The magnitude of the directional dichroism critically depends on the magnetic-field direction. Such behavior is well accounted for by considering the relative direction of the oscillating electric polarizations induced via the ME effect with respect to microwave electric fields. Directional dichroism in a system with an arbitrary form of ME coupling can be also discussed in the same manner.

  18. Rheological and sensory behaviors of parboiled pasta cooked using a microwave pasteurization process.

    Science.gov (United States)

    Joyner, Helen S; Jones, Kari E; Rasco, Barbara A

    2017-10-01

    Pasta hydration and cooking requirements make in-package microwave pasteurization of pasta a processing challenge. The objective of this study was to assess instrumental and sensory attributes of microwave-treated pasta in comparison to conventionally cooked pasta. Fettuccine pasta was parboiled for 0, 3, 6, 9, or 12 min, pasteurized by microwaves at 915 MHz, then stored under refrigeration for 1 week. Pastas were evaluated by a trained sensory panel and with rheometry. Total pasta heat treatment affected both rheological and sensory behaviors; these differences were attributed to ultrastructure differences. Significant nonlinear behavior and dominant fluid-like behavior was observed in all pastas at strains >1%. Sensory results suggested microwave pasteurization may intensify the attributes associated with the aging of pasta such as retrogradation. A clear trend between magnitude of heat treatment and attribute intensity was not observed for all sensory attributes tested. The microwave pasta with the longest parboil time showed rheological behavior most similar to conventionally cooked pasta. Principal component analysis revealed that no microwave-treated pasta was similar to the control pasta. However, pasta parboiled for 9 min before microwave treatment had the greatest number of similar sensory attributes, followed by pasta parboiled for 6 or 12 min. Further study is needed to determine overall consumer acceptance of microwave-treated pasta and whether the differences in sensory and rheological behavior would impact consumer liking. The results of this study may be applied to optimize microwave pasteurization processes for cooked pasta and similar products, such as rice. The measurement and analysis procedures can be used to evaluate processing effects on a variety of different foods to determine overall palatability. © 2017 Wiley Periodicals, Inc.

  19. Microwave Propagation Through Cultural Vegetation Canopies

    Science.gov (United States)

    Tavakoli, Ahad

    The need to understand the interaction of microwaves with vegetation canopies has markedly increased in recent years. This is due to advances made in remote sensing science, microwave technology, and signal processing circuits. One class of the earth's vegetation cover is man-made canopies, such as agricultural fields, orchards, and artificial forests. Contrary to natural vegetation terrain, location, spacing, and density of plants in a man-made vegetation canopy are deterministic quantities. As a result, the semi-deterministic nature of cultural vegetation canopies violate the random assumption of the radiative transfer theory and leads to experimented results that are in variance with model calculations. Hence, an alternative approach is needed to model the interaction of microwaves with such canopies. This thesis examines the propagation behavior through a canopy of corn plants. The corn canopy was selected as a representative of cultural vegetation canopies that are planted in parallel rows with an approximately fixed spacing between adjacent plants. Several experimental measurements were conducted to determine the transmission properties of a corn canopy in the 1-10 GHz range. The measurements which included horizontal propagation through the canopy as well as propagation at oblique incidence, were performed for defoliated canopies and for canopies with leaves. Through experimental observations and model development, the propagation behavior was found to be strongly dependent on the wavelength and the path length. At a wavelength in the neighborhood of 20 cm, for example, it was found that scattering by the stalks was coherent in nature for waves propagating horizontally through the canopy, which necessitated the development of a coherent-field model that uses Bragg scattering to account for the observed interference pattern in the transmitted beam. As the wavelength is made shorter, the semi-random spacing between plants becomes significant relative to the

  20. Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

    Directory of Open Access Journals (Sweden)

    Akshata M. K.

    2018-01-01

    Full Text Available Small and large scale (gas power plant, hydro power plant, automobile industries are suffering by failure of component. Sometimes, it is also observed that the component which was failed due to these reasons are very much costly and replacement of those also very difficult due to the complex geometry. By using Microwave hybrid heating, WC-12Co based clads were developed on austenitic stainless steel (SS304. Microwave clads were developed by introducing the preplaced, preheated powder for a duration of 15 min to microwave radiation at 2.45GHz frequency and 900 W power in domestic microwave applicator. By using optical microscope and scanning electron microscope (SEM, the developed clads were characterized. By using pin-on-disk, wear performance of the WC-12Co based clads and unclad samples were tested. It is observed that developed clad samples performed superior wear resistance than unclad samples.

  1. Probing Large-Angle Correlations with the Microwave Background Temperature and Lensing Cross Correlation

    CERN Document Server

    Yoho, A; Starkman, G D; Kosowsky, A

    2014-01-01

    A lack of correlations in the microwave background temperature between sky directions separated by angles larger than 60 degrees has recently been confirmed by data from the Planck satellite. This feature arises as a random occurrence within the standard LCDM cosmological model less than 0.3 per cent of the time, but so far no other compelling theory to explain this observation has been proposed. Here we investigate the theoretical cross-correlation function between microwave background temperature and the gravitational lensing potential of the microwave background, which in contrast to the temperature correlation function depends strongly on gravitational potential fluctuations interior to our Hubble volume. For standard LCDM cosmology, we generate random sky realizations of the microwave temperature and gravitational lensing, subject to the constraint that the temperature correlation function matches observations, and compare with random skies lacking this constraint. The distribution of large-angle tempera...

  2. Microbial inactivation by microwave radiation in the home environment.

    Science.gov (United States)

    Park, Dong-Kyoo; Bitton, Gabriel; Melker, Richard

    2006-12-01

    The study reported here looked at the survival of microorganisms (heterotrophic plate counts, total coliforms, E. coli, and bacterial spores) in a consumer-type microwave oven. Kitchen sponges, scrubbing pads, and syringes were experimentally contaminated with wastewater and subsequently exposed to microwave radiation. At 100 percent power level, it was found that the heterotrophic plate count (i.e., total bacterial count) of the wastewater was reduced by more that 99 percent within 1 to 2 minutes, and the total coliform and E. coli were totally inactivated after 30 seconds of microwave radiation. Bacterial phage MS2 was totally inactivated within 1 to 2 minutes. Spores of Bacillus cereus were more resistant than the other microorganisms tested, and were completely eradicated only after 4-minute irradiation. Similar inactivation rates were obtained in wastewater-contaminated scrubbing pads. Microorganisms attached to plastic syringes were more resistant to microwave irradiation than those associated with kitchen sponges or scrubbing pads. It took 10 minutes for total inactivation of the heterotrophic plate count and 4 minutes for total inactivation of total coliform and E. coli. A 4-log reduction of phage MS2 was obtained after 2 minutes; 97.4 percent reduction was observed after 12 minutes. The authors also observed a higher inactivation of B. cereus spores in syringes placed in a ceramic container than of spores in syringes placed in a glass container. This finding could have some implications for the design of containers to be used in exposure of medical devices to microwave radiation. The article discusses the implications of these findings for consumer safety in the home environment.

  3. Study of microwave components for an electron cyclotron resonance ...

    Indian Academy of Sciences (India)

    rious aspects of the microwave system including design, fabrication, characterization and performance studies of the microwave components. Keywords. Microwave system; microwave studio software; network analyser; electron cyclotron resonance ion source. 1. Introduction. Microwave systems at 2.45 GHz have been ...

  4. Control of microwave heating of peritoneal dialysis solutions.

    Science.gov (United States)

    Deutschendorf, A F; Wenk, R E; Lustgarten, J; Mason, P

    1994-01-01

    To determine if microwave heating of dialysis solutions to 37 degrees C produced focal overheating (hot spots) and caramelization of dextrose. In vitro determination of conditions for controlling time, temperature, and procedures. Bags had been stored at ambient room temperature. Solution and external bag surface temperature determinations. Dextrose degradation products determined spectrophotometrically. Microscopy for potential caramel precipitates. A microwave oven with no rotation tray produced uneven heating of bags of two commercially available concentrations of dialysis solutions. The greatest hot spots were evident in spike ports. External bag surface temperatures were within 0.20 degrees C of reservoir temperatures. Initial solution temperatures correlated with temperatures of the solutions after microwave heating (r = 0.895). No statistically significant differences were found between dextrose degradation product concentrations of unheated and heated solutions, including hot spots. No precipitates were observed microscopically. Despite the presence of solution hot spots in bag infusion ports, 37 degrees C temperatures were achievable in the bag reservoirs with no evidence of increased glucose degradation. This outcome is assured if the initial temperature and the microwave conditions (procedure, time, mixing of solution) are held constant, and the external bag temperatures are measured after heating.

  5. Fine and ultrafine particle emissions from microwave popcorn.

    Science.gov (United States)

    Zhang, Q; Avalos, J; Zhu, Y

    2014-04-01

    This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10(10) to 8.0 × 10(10) No./min for total particle number and from 134 to 249 μg/min for PM2.5 . © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Specific energy consumption in microwave drying of garlic cloves

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, G.P. [Department of Processing and Food Engineering, College of Technology and Agricultural Engineering, Udaipur 313 001, Rajasthan (India); Prasad, Suresh [Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur 721 302 (India)

    2006-09-15

    The convective and microwave-convective drying of garlic cloves was carried out in a laboratory scale microwave dryer, which was developed for this purpose. The specific energy consumption involved in the two drying processes was estimated from the energy supplied to the various components of the dryer during the drying period. The specific energy consumption was computed by dividing the total energy supplied by amount of water removed during the drying process. The specific energy consumption in convective drying of garlic cloves at 70{sup o}C temperature and 1.0m/s air velocity was estimated as 85.45MJ/kg of water evaporated. The increase in air velocity increased the energy consumption. The specific energy consumption at 40W of microwave power output, 70{sup o}C air temperature and 1.0m/s air velocity was 26.32MJ/kg of water removed, resulting in about a 70% energy saving as compared to convective drying processes. The drying time increased with increase in air velocity in microwave-convective drying process; a trend reverse to what was observed in convective drying process of garlic cloves. (author)

  7. Effect of 2450 MHz microwave radiation on the ultrastructure of snail neurons

    Energy Technology Data Exchange (ETDEWEB)

    Arber, S.L.; Neilly, J.P.; Lin, J.C.; Kriho, V.

    1986-01-01

    An electron microscopical study of snail neurons was undertaken to verify whether any ultrastructural alterations accompany microwave-induced electrophysiological changes observed in these neurons. Subesophageal ganglia from Helix aspersa snails were exposed to 2450 MHz microwave radiation in vitro at SAR 12.9 mW/g for 60 minutes. It was found that exposure at 21 degrees C causes minor changes in Golgi complexes and slight swelling of the endoplasmic reticulum.

  8. On the existence of and mechanism for microwave-specific reaction rate enhancement.

    Science.gov (United States)

    Dudley, Gregory B; Richert, Ranko; Stiegman, A E

    2015-04-01

    The use of microwave radiation to drive chemical reactions has become ubiquitous in almost all fields of chemistry. In all of these areas it is principally due to rapid and convenient heating resulting in significantly higher rates of reaction, with other advantages including enhanced product selectivity and control of materials properties. Although microwave heating continues to grow as an enabling technology, fundamental research into the nature of microwave heating has not grown at the same rate. In the case of chemical reactions run in homogeneous solution, particularly synthetic organic reactions, there is considerable controversy over the origins of rate enhancement, with a fundamental question being whether there exist microwave-specific effects, distinct from what can be attained under conventional convective heating, that can accelerate a reaction rate. In this Perspective, we discuss unique aspects of microwave heating of molecules in solution and discuss the origin and nature of microwave-specific effects arising from the process of "selective heating" of reactants in solution. Integral to this discussion is work from the field of dielectric relaxation spectroscopy, which provides a model for selective heating by Debye relaxation processes. The Perspective also includes a critical discussion of hypotheses of non-thermal effects (alternatively classified here as resonant processes) and an outline of specific reaction parameters for chemical systems in which microwave-specific Debye relaxation processes can result in observable reaction rate enhancement.

  9. Magnetic Resonance with Squeezed Microwaves

    Science.gov (United States)

    Bienfait, A.; Campagne-Ibarcq, P.; Kiilerich, A. H.; Zhou, X.; Probst, S.; Pla, J. J.; Schenkel, T.; Vion, D.; Esteve, D.; Morton, J. J. L.; Moelmer, K.; Bertet, P.

    2017-10-01

    Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states of light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures. By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a 1.2-dB noise reduction at the spectrometer output compared to the case of a vacuum input. This result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.

  10. Microwave waste processing technology overview

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, R.D.

    1993-02-01

    Applications using microwave energy in the chemical processing industry have increased within the last ten years. Recently, interest in waste treatment applications process development, especially solidification, has grown. Microwave waste processing offers many advantages over conventional waste treatment technologies. These advantages include a high density, leach resistant, robust waste form, volume and toxicity reduction, favorable economics, in-container treatment, good public acceptance, isolated equipment, and instantaneous energy control. The results from the {open_quotes}cold{close_quotes} demonstration scale testing at the Rocky Flats nuclear weapons facility are described. Preliminary results for a transuranic (TRU) precipitation sludge indicate that volume reductions of over 80% are achievable over the current immobilization process. An economic evaluation performed demonstrated cost savings of $11.68 per pound compared to the immobilization process currently in use on wet sludge.

  11. Tapping mode microwave impedance microscopy

    KAUST Repository

    Lai, K.

    2009-01-01

    We report tapping mode microwave impedance imaging based on atomic force microscope platforms. The shielded cantilever probe is critical to localize the tip-sample interaction near the tip apex. The modulated tip-sample impedance can be accurately simulated by the finite-element analysis and the result agrees quantitatively to the experimental data on a series of thin-film dielectric samples. The tapping mode microwave imaging is also superior to the contact mode in that the thermal drift in a long time scale is totally eliminated and an absolute measurement on the dielectric properties is possible. We demonstrated tapping images on working nanodevices, and the data are consistent with the transport results. © 2009 American Institute of Physics.

  12. Displacement of squeezed propagating microwave states

    Science.gov (United States)

    Fedorov, Kirill G.; Zhong, Ling; Pogorzalek, Stefan; Eder, Peter; Fischer, Michael; Goetz, Jan; Wulschner, Friedrich; Xie, Edwar; Menzel, Edwin; Deppe, Frank; Marx, Achim; Gross, Rudolf

    Displacement of propagating squeezed states is a fundamental operation for quantum communications. It can be applied to fundamental studies of macroscopic quantum coherence and has an important role in quantum teleportation protocols with propagating microwaves. We generate propagating squeezed states using a Josephson parametric amplifier and implement displacement using a cryogenic directional coupler. We study single- and two-mode displacement regimes. For the single-mode displacement we find that the squeezing level of the displaced squeezed state does not depend on the displacement amplitude. Also, we observe that quantum entanglement between two spatially separated channels stays constant across 4 orders of displacement power. We acknowledge support by the German Research Foundation through SFB 631 and FE 1564/1-1, the EU project PROMISCE, and Elite Network of Bavaria through the program ExQM.

  13. Time-of-Flight Microwave Camera.

    Science.gov (United States)

    Charvat, Gregory; Temme, Andrew; Feigin, Micha; Raskar, Ramesh

    2015-10-05

    Microwaves can penetrate many obstructions that are opaque at visible wavelengths, however microwave imaging is challenging due to resolution limits associated with relatively small apertures and unrecoverable "stealth" regions due to the specularity of most objects at microwave frequencies. We demonstrate a multispectral time-of-flight microwave imaging system which overcomes these challenges with a large passive aperture to improve lateral resolution, multiple illumination points with a data fusion method to reduce stealth regions, and a frequency modulated continuous wave (FMCW) receiver to achieve depth resolution. The camera captures images with a resolution of 1.5 degrees, multispectral images across the X frequency band (8 GHz-12 GHz), and a time resolution of 200 ps (6 cm optical path in free space). Images are taken of objects in free space as well as behind drywall and plywood. This architecture allows "camera-like" behavior from a microwave imaging system and is practical for imaging everyday objects in the microwave spectrum.

  14. Microwave chemistry for inorganic nanomaterials synthesis.

    Science.gov (United States)

    Bilecka, Idalia; Niederberger, Markus

    2010-08-01

    This Feature Article gives an overview of microwave-assisted liquid phase routes to inorganic nanomaterials. Whereas microwave chemistry is a well-established technique in organic synthesis, its use in inorganic nanomaterials' synthesis is still at the beginning and far away from having reached its full potential. However, the rapidly growing number of publications in this field suggests that microwave chemistry will play an outstanding role in the broad field of Nanoscience and Nanotechnology. This article is not meant to give an exhaustive overview of all nanomaterials synthesized by the microwave technique, but to discuss the new opportunities that arise as a result of the unique features of microwave chemistry. Principles, advantages and limitations of microwave chemistry are introduced, its application in the synthesis of different classes of functional nanomaterials is discussed, and finally expected benefits for nanomaterials' synthesis are elaborated.

  15. Note: cryogenic coaxial microwave filters.

    Science.gov (United States)

    Tancredi, G; Schmidlin, S; Meeson, P J

    2014-02-01

    The careful filtering of microwave electromagnetic radiation is critical for controlling the electromagnetic environment for experiments in solid-state quantum information processing and quantum metrology at millikelvin temperatures. We describe the design and fabrication of a coaxial filter assembly and demonstrate that its performance is in excellent agreement with theoretical modelling. We further perform an indicative test of the operation of the filters by making current-voltage measurements of small, underdamped Josephson junctions at 15 mK.

  16. Compact planar microwave blocking filters

    Science.gov (United States)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  17. Comparing Cosmic Microwave Background Datasets

    OpenAIRE

    Knox, L.; Bond, J..R.; Jaffe, A. H.; Segal, M; Charbonneau, D

    1998-01-01

    To extract reliable cosmic parameters from cosmic microwave background datasets, it is essential to show that the data are not contaminated by residual non-cosmological signals. We describe general statistical approaches to this problem, with an emphasis on the case in which there are two datasets that can be checked for consistency. A first visual step is the Wiener filter mapping from one set of data onto the pixel basis of another. For more quantitative analyses we develop and apply both B...

  18. Directional microwave applicator and methods

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Lin, Greg Y. (Inventor); Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor)

    2008-01-01

    A miniature microwave antenna is disclosed which may be utilized for biomedical applications such as, for example, radiation induced hyperthermia through catheter systems. One feature of the antenna is that it possesses azimuthal directionality despite its small size. This directionality permits targeting of certain tissues while limiting thermal exposure of adjacent tissue. One embodiment has an outer diameter of about 0.095'' (2.4 mm) but the design permits for smaller diameters.

  19. Microwave remote sensing measurements of oil pollution on the ocean

    Science.gov (United States)

    Croswell, W. F.; Blume, H.-J. C.; Johnson, J. W.

    1981-01-01

    Microwave and optical remote sensors were flown over fresh and weathered crude oil released from a surface research vessel and also over a slick formed on the sea by frozen oleyl alcohol cubes released from a helicopter. For the crude oil experiments, microwave radiometric measurements at 1.43, 2.65, 22, and 31 GHz are reported, along with the variable incidence angle scattering measurements at 13.9 GHz. For these experiments, unusual depressions in the L-band brightness temperature were observed, possibly related to dispersants applied to the crude oil. Similar depressions, but with much larger values, were observed over the oleyl alcohol monomolecular slicks. Images obtained at 31 and 22 GHz were used to infer oil volume, yielding values which bound the known amounts spilled. Ku band measurements obtained in repeated passes over crude oil slicks are also discussed.

  20. Microwave thawing of frozen parenteral solutions.

    Science.gov (United States)

    Walter, C W; Pauly, J A; Ausman, R K; Kundsin, R B; Holmes, C J

    1983-01-01

    A commercially available microwave oven modified for use at medication stations throughout hospitals allows timely thawing of frozen parenteral solutions. The inherent problems of safety and uniform heating have been overcome, thus making possible the preparation, storage, and distribution of admixtures on a regional basis and ensuring the integrity of the product. Most parenteral medications are not degraded by microwave energy, and thawing by microwave energy permits timely administration and allows coordination of medication for a series of patients.

  1. Harmonic distortion in microwave photonic filters.

    Science.gov (United States)

    Rius, Manuel; Mora, José; Bolea, Mario; Capmany, José

    2012-04-09

    We present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation.

  2. Effect of chronic microwave radiation on T cell-mediated immunity in the rabbit

    Science.gov (United States)

    Nageswari, K. Sri; Sarma, K. R.; Rajvanshi, V. S.; Sharan, R.; Sharma, Manju; Barathwal, Vinita; Singh, Vinod

    1991-06-01

    Experiments were conducted to elucidate the effects of chronic low power-level microwave radiation on the immunological systems of rabbits. Fourteen male Belgian white rabbits were exposed to microwave radiation at 5 mW/cm2, 2.1 GHz, 3 h daily, 6 days/week for 3 months in two batches of 7 each in specially designed miniature anechoicchambers. Seven rabbits were subjected to sham exposure for identical duration. The microwave energy was provided through S band standard gain horns connected to a 4K3SJ2 Klystron power amplifier. The first batch of animals were assessed for T lymphocyte-mediated cellular immune response mechanisms and the second batch of animals for B lymphocyte-mediated humoral immune response mechanisms. The peripheral blood samples collected monthly during microwave/sham exposure and during follow-up (5/14 days after termination of exposures, in the second batch animals only) were analysed for T lymphocyte numbers and their mitogen responsiveness to ConA and PHA. Significant suppression of T lymphocyte numbers was noted in the microwave group at 2 months ( Plymphocyte counts (spleen and lymph node) were analysed. No significant variation was observed in the tissue T lymphocyte counts of microwave-irradiated rabbits. From these results it is speculated that the T lymphocytes are sequestered to various lymphoid organs under the influence of microwaves. A sub-population of T cells known as T helper cells (mediating DTH response) are probably not affected by microwave radiation. It is clear from our experiments that although chronic microwave radiation at 5 mW/cm2 leads to suppression of peripheral T lymphocyte numbers, there is no concomitant functional impairment of these cells as evidenced by functional assays.

  3. Comparative microstructure study of oil palm fruit bunch fibre, mesocarp and kernels after microwave pre-treatment

    Science.gov (United States)

    Chang, Jessie S. L.; Chan, Y. S.; Law, M. C.; Leo, C. P.

    2017-07-01

    The implementation of microwave technology in palm oil processing offers numerous advantages; besides elimination of polluted palm oil mill effluent, it also reduces energy consumption, processing time and space. However, microwave exposure could damage a material’s microstructure which affected the quality of fruit that can be related to its physical structure including the texture and appearance. In this work, empty fruit bunches, mesocarp and kernel was microwave dried and their respective microstructures were examined. The microwave pretreatments were conducted at 100W and 200W and the microstructure investigation of both treated and untreated samples were evaluated using scanning electron microscope. The micrographs demonstrated that microwave does not significantly influence kernel and mesocarp but noticeable change was found on the empty fruit bunches where the sizes of the granular starch were reduced and a small portion of the silica bodies were disrupted. From the experimental data, the microwave irradiation was shown to be efficiently applied on empty fruit bunches followed by mesocarp and kernel as significant weight loss and size reduction was observed after the microwave treatments. The current work showed that microwave treatment did not change the physical surfaces of samples but sample shrinkage is observed.

  4. Microwave radiation (2.45 GHz)-induced oxidative stress: Whole-body exposure effect on histopathology of Wistar rats.

    Science.gov (United States)

    Chauhan, Parul; Verma, H N; Sisodia, Rashmi; Kesari, Kavindra Kumar

    2017-01-01

    Man-made microwave and radiofrequency (RF) radiation technologies have been steadily increasing with the growing demand of electronic appliances such as microwave oven and cell phones. These appliances affect biological systems by increasing free radicals, thus leading to oxidative damage. The aim of this study was to explore the effect of 2.45 GHz microwave radiation on histology and the level of lipid peroxide (LPO) in Wistar rats. Sixty-day-old male Wistar rats with 180 ± 10 g body weight were used for this study. Animals were divided into two groups: sham exposed (control) and microwave exposed. These animals were exposed for 2 h a day for 35 d to 2.45 GHz microwave radiation (power density, 0.2 mW/cm(2)). The whole-body specific absorption rate (SAR) was estimated to be 0.14 W/kg. After completion of the exposure period, rats were sacrificed, and brain, liver, kidney, testis and spleen were stored/preserved for determination of LPO and histological parameters. Significantly high level of LPO was observed in the liver (p microwave radiation. Also histological changes were observed in the brain, liver, testis, kidney and spleen after whole-body microwave exposure, compared to the control group. Based on the results obtained in this study, we conclude that exposure to microwave radiation 2 h a day for 35 d can potentially cause histopathology and oxidative changes in Wistar rats. These results indicate possible implications of such exposure on human health.

  5. TCSP ER-2 MICROWAVE TEMPERATURE PROFILER (MTP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The TCSP ER-2 Microwave Temperature Profiler (MTP) dataset was collected by the ER-2 Microwave Temperature Profiler (MTP), which is a passive microwave radiometer...

  6. The Cosmic Microwave Background

    Science.gov (United States)

    Rubiño-Martin, Jose Alberto; Rebolo, Rafael; Mediavilla, Evencio

    2013-12-01

    List of contributors; List of participants; Preface; Acknowledgements; 1. CMB observations and cosmological constraints Bruce Partridge; 2. The inflationary universe Sabino Matarrese; 3. CMB theory from nucleosynthesis to recombination Wayne Hu; 4. CMB fluctuations in the post-recombination universe Matthias Bartelmann; 5. Statistical techniques for data analysis in cosmology Licia Verde; 6. Gaussianity Enrique Martínez-González; 7. Galactic and extragalactic foregrounds Rodney D. Davies; 8. Probes of fundamental cosmology Malcolm Longair.

  7. Crystallization and activation of silicon by microwave rapid annealing

    Science.gov (United States)

    Kimura, Shunsuke; Ota, Kosuke; Hasumi, Masahiko; Suzuki, Ayuta; Ushijima, Mitsuru; Sameshima, Toshiyuki

    2016-07-01

    A combination of the carbon-powder absorber with microwave irradiation is proposed as a rapid heat method. 2-μm-diameter carbon powders with a packing density of 0.08 effectively absorbed 2.45 GHz 1000-W-microwave and heated themselves to 1163 °C for 26 s. The present heat treatment recrystallized n-type crystalline silicon surfaces implanted with 1.0 × 10^{15}hbox {-cm}^{-2}-boron and phosphorus atoms with crystalline volume ratios of 0.99 and 0.93, respectively, by microwave irradiation at 1000 W for 20 s. Activation and carrier generation were simultaneously achieved with a sheet resistivity of 62 Ω / hbox {sq}. A high photo-induced-carrier effective lifetime of 1.0 × 10^{-4} s was also achieved. Typical electrical current-rectified characteristic and solar cell characteristic with an efficiency of 12.1 % under 100-mW/cm2-air-mass-1.5 illumination were obtained. Moreover, heat treatment with microwave irradiation at 1000 W for 22 s successfully crystallized silicon thin films with thicknesses ranging from 2.4 to 50 nm formed on quartz substrates. Nano-crystalline cluster structure with a high volume ratio of 50 % was formed in the 1.8-nm (initial 2.4-nm)-thick silicon films. Photoluminescence around 1.77 eV was observed for the 1.8-nm-thick silicon films annealed at 260 °C in 1.3 × 106-Pa-H2O-vapor for 3 h after the microwave heating.

  8. Experimental Investigation of Magnetic Nanoparticle-Enhanced Microwave Hyperthermia.

    Science.gov (United States)

    McWilliams, Brogan T; Wang, Hongwang; Binns, Valerie J; Curto, Sergio; Bossmann, Stefan H; Prakash, Punit

    2017-06-22

    The objective of this study was to evaluate microwave heating enhancements offered by iron/iron oxide nanoparticles dispersed within tissue-mimicking media for improving efficacy of microwave thermal therapy. The following dopamine-coated magnetic nanoparticles (MNPs) were considered: 10 and 20 nm diameter spherical core/shell Fe/Fe₃O₄, 20 nm edge-length cubic Fe₃O₄, and 45 nm edge-length/10 nm height hexagonal Fe₃O₄. Microwave heating enhancements were experimentally measured with MNPs dissolved in an agar phantom, placed within a rectangular waveguide. Effects of MNP concentration (2.5-20 mg/mL) and microwave frequency (2.0, 2.45 and 2.6 GHz) were evaluated. Further tests with 10 and 20 nm diameter spherical MNPs dispersed within a two-compartment tissue-mimicking phantom were performed with an interstitial dipole antenna radiating 15 W power at 2.45 GHz. Microwave heating of 5 mg/mL MNP-agar phantom mixtures with 10 and 20 nm spherical, and hexagonal MNPs in a waveguide yielded heating rates of 0.78 ± 0.02 °C/s, 0.72 ± 0.01 °C/s and 0.51 ± 0.03 °C/s, respectively, compared to 0.5 ± 0.1 °C/s for control. Greater heating enhancements were observed at 2.0 GHz compared to 2.45 and 2.6 GHz. Heating experiments in two-compartment phantoms with an interstitial dipole antenna demonstrated potential for extending the radial extent of therapeutic heating with 10 and 20 nm diameter spherical MNPs, compared to homogeneous phantoms (i.e., without MNPs). Of the MNPs considered in this study, spherical Fe/Fe₃O₄ nanoparticles offer the greatest heating enhancement when exposed to microwave radiation. These nanoparticles show strong potential for enhancing the rate of heating and radial extent of heating during microwave hyperthermia and ablation procedures.

  9. Experimental Investigation of Magnetic Nanoparticle-Enhanced Microwave Hyperthermia

    Directory of Open Access Journals (Sweden)

    Brogan T. McWilliams

    2017-06-01

    Full Text Available The objective of this study was to evaluate microwave heating enhancements offered by iron/iron oxide nanoparticles dispersed within tissue-mimicking media for improving efficacy of microwave thermal therapy. The following dopamine-coated magnetic nanoparticles (MNPs were considered: 10 and 20 nm diameter spherical core/shell Fe/Fe3O4, 20 nm edge-length cubic Fe3O4, and 45 nm edge-length/10 nm height hexagonal Fe3O4. Microwave heating enhancements were experimentally measured with MNPs dissolved in an agar phantom, placed within a rectangular waveguide. Effects of MNP concentration (2.5–20 mg/mL and microwave frequency (2.0, 2.45 and 2.6 GHz were evaluated. Further tests with 10 and 20 nm diameter spherical MNPs dispersed within a two-compartment tissue-mimicking phantom were performed with an interstitial dipole antenna radiating 15 W power at 2.45 GHz. Microwave heating of 5 mg/mL MNP-agar phantom mixtures with 10 and 20 nm spherical, and hexagonal MNPs in a waveguide yielded heating rates of 0.78 ± 0.02 °C/s, 0.72 ± 0.01 °C/s and 0.51 ± 0.03 °C/s, respectively, compared to 0.5 ± 0.1 °C/s for control. Greater heating enhancements were observed at 2.0 GHz compared to 2.45 and 2.6 GHz. Heating experiments in two-compartment phantoms with an interstitial dipole antenna demonstrated potential for extending the radial extent of therapeutic heating with 10 and 20 nm diameter spherical MNPs, compared to homogeneous phantoms (i.e., without MNPs. Of the MNPs considered in this study, spherical Fe/Fe3O4 nanoparticles offer the greatest heating enhancement when exposed to microwave radiation. These nanoparticles show strong potential for enhancing the rate of heating and radial extent of heating during microwave hyperthermia and ablation procedures.

  10. Advanced Microwave Electrothermal Thruster (AMET) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Orbital Technologies Corporation (ORBITEC) and the University of Alabama at Huntsville (UAH) propose to develop the Advanced Microwave Electrothermal Thruster...

  11. Compact superconducting coplanar microwave beam splitters

    Energy Technology Data Exchange (ETDEWEB)

    Baust, Alexander; Haeberlein, Max; Goetz, Jan; Hoffmann, Elisabeth; Menzel, Edwin P.; Schwarz, Manuel J.; Wulschner, Friedrich; Zhong, Ling; Deppe, Frank; Marx, Achim; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TUM, Garching (Germany); Kalb, Norbert; Losinger, Thomas [Physik-Department, TUM, Garching (Germany)

    2012-07-01

    The recent evolution of circuit quantum electrodynamics systems making use of standing-wave microwave modes towards setups for propagating quantum microwaves has triggered the need for low-loss superconducting microwave beam splitters. Such a device should have ports compatible with the coplanar geometry relevant for circuit QED and, at the same time, be compact allowing for scalability. This combination presents fundamental and technological challenges. In this work, we present the fabrication and characterization of various compact superconducting coplanar microwave beam splitters. In addition, we discuss efforts towards a tunable beam splitter.

  12. Use of microwave in diagnostic pathology

    Directory of Open Access Journals (Sweden)

    Basavaradhya Sahukar Shruthi

    2013-01-01

    Microwaves a form of electromagnetic wave-induced heat, when applied in histotechnology, reproducibly yields histolologic material of similar or superior quality to that provided by conventional processing methods, making it more popular in the recent years. A laboratory microwave offers features like maximum output of 2000-3000 watts, an in-built source of adjustable temperature probe, facility for ventilation of hazardous fumes, but is expensive. Considering the usefulness of microwave in histotechnology, i.e., reducing the time required for the diagnosis, replacing the conventional equipments of laboratories by microwave-guided ones is a remarkable and an acceptable change.

  13. Microwave power engineering generation, transmission, rectification

    CERN Document Server

    Okress, Ernest C

    1968-01-01

    Microwave Power Engineering, Volume 1: Generation, Transmission, Rectification considers the components, systems, and applications and the prevailing limitations of the microwave power technology. This book contains four chapters and begins with an introduction to the basic concept and developments of microwave power technology. The second chapter deals with the development of the main classes of high-power microwave and optical frequency power generators, such as magnetrons, crossed-field amplifiers, klystrons, beam plasma amplifiers, crossed-field noise sources, triodes, lasers. The third

  14. Time-of-Flight Microwave Camera

    National Research Council Canada - National Science Library

    Charvat, Gregory; Temme, Andrew; Feigin, Micha; Raskar, Ramesh

    2015-01-01

    .... We demonstrate a multispectral time-of-flight microwave imaging system which overcomes these challenges with a large passive aperture to improve lateral resolution, multiple illumination points...

  15. Simple microwave preionization source for ohmic plasmas

    Science.gov (United States)

    Choe, W.; Kwon, Gi-Chung; Kim, Junghee; Kim, Jayhyun; Jeon, Sang-Jean; Huh, Songwhe

    2000-07-01

    A simple economical 2.45 GHz microwave system has been developed and utilized for preionization on the Korea Advanced Institute of Science and Technology (KAIST)-TOKAMAK. The magnetron microwave source was obtained from a widely used, household microwave oven. Since ac operation of the magnetron is not suitable for tokamak application, the magnetron cathode bias circuit was modified to obtain continuous and stable operation of the magnetron for several hundred milliseconds. Application of the developed microwave system to KAIST-TOKAMAK resulted in a reduction of ohmic flux consumption.

  16. Stable microwave-assisted magnetization switching for nanoscale exchange-coupled composite grain

    Science.gov (United States)

    Tanaka, Terumitsu; Kashiwagi, Shota; Furomoto, Yoshitoki; Otsuka, Yuto; Matsuyama, Kimihide

    2013-11-01

    Magnetization mechanisms of nanoscale magnetic grains greatly differ from well-known magnetization mechanisms of micrometer- or millimeter-sized magnetic grains or particles. Magnetization switching mechanisms of nanoscale exchange-coupled composite (ECC) grain in a microwave field was studied using micromagnetic simulation. Magnetization switching involving a strongly damped or precessional oscillation was studied using various strengths of external direct current and microwave fields. These studies imply that the switching behavior of microwave-assisted magnetization switching of the ECC grain can be divided into two groups: stable and unstable regions, similar to the case of the Stoner-Wahlfarth grain. A significant reduction in the switching field was observed in the ECC grain when the magnetization switching involved precessional oscillations similar to the case of the Stoner-Wohlfarth grain. This switching behavior is preferred for the practical applications of microwave-assisted magnetization switching.

  17. Microwave-superheated Vics Vapo Rub: an ocular public health danger.

    Science.gov (United States)

    Fung, Anne E; Oxford, Karen W

    2004-02-01

    To report a case of a microwave-oven superheated petroleum-based liquid causing severe chemical and thermal ocular burns treated successfully with amniotic membrane transplantation. Observational case report. Retrospective review of clinical case. A 77-year-old woman sustained a severe combined chemical and thermal burn from microwave-heated Vicks Vapo-Rub requiring amniotic membrane transplant, with subsequent development of phacomorphic glaucoma, requiring cataract extraction, and bullous keratopathy, requiring penetrating keratoplasty. As microwave oven use becomes more commonplace, the risk of superheating liquids becomes an increasingly significant ocular danger. Continued efforts to educate the public about safe microwave use is necessary. Additionally, amniotic membrane transplantation was found to be effective in managing a combined chemical and thermal ocular burn.

  18. Morphological Characterization Of Titania Slag Obtained From Red Sediment Placer Ilmenite Using Microwave Energy

    Science.gov (United States)

    Srikant, S. S.; Mukherjee, P. S.; Bhima Rao, R.

    2015-04-01

    This paper deals with the main objective to observe the effect of microwave heat treatment for the production of Titania rich slag and pig iron from placer ilmenite. The experiments carried out in the present investigation on the oxidized ilmenite sample for microwave heat treatment in microwave sintering furnace reveals that a product can be obtained containing Titania rich slag and metalized iron. The in-depth characterisation of these products using SEM-EDAX shows that around 75-85 % of titanium dioxide is formed in terms of titania rich slag by using microwave sintering furnace after reduction of oxidized ilmenite with proper stoichiometric graphitic carbon and silicon carbide (SiC) susceptor. The titania rich slag is considered to be better input material for production of pigment grade titanium dioxide. On the other hand, the pig iron obtained as by product from titania rich slag is also important for automobile and steel industries application.

  19. Topological trajectories of a magnetic skyrmion with an in-plane microwave magnetic field

    Science.gov (United States)

    Jin, Chendong; Song, Chengkun; Wang, Jinshuai; Xia, Haiyan; Wang, Jianbo; Liu, Qingfang

    2017-12-01

    Magnetic skyrmions are stable and topologically protected spin textures which have been observed in several chiral magnetic materials, and the resonant excitations of magnetic skyrmions have become a hot research topic for potential applications in future microwave devices. In this work, we investigate in-plane microwave-induced topological dynamics of a magnetic skyrmion in a nanodisk by using micromagnetic simulations. It is found that the resonant excitations of the skyrmion are elliptical dynamics which contain counterclockwise and clockwise modes by applying different frequencies of the microwave field. The conversion between these two elliptical modes is achieved by a transition to linear vibration. In addition, we demonstrate that the off-centered process of the skyrmion can be controlled by applying different phases of the microwave field. Finally, we discuss the different topological excitations of four types of skyrmions. Our results present the understanding of topological skyrmion dynamics and may also provide a method to control skyrmions in nanodevices.

  20. Nonselective excitation of pulsed ELDOR using multi-frequency microwaves

    Science.gov (United States)

    Asada, Yuki; Mutoh, Risa; Ishiura, Masahiro; Mino, Hiroyuki

    2011-12-01

    The use of a polychromatic microwave pulse to expand the pumping bandwidth in pulsed electron-electron double resonance (PELDOR) was investigated. The pumping pulse was applied in resonance with the broad (˜100 mT) electron paramagnetic resonance (EPR) signal of the manganese cluster of photosystem II in the S 2 state. The observation pulses were in resonance with the narrow EPR signal of the tyrosine radical, YDrad . It was found that in the case of the polychromatic pumping pulse containing five harmonics with the microwave frequencies between 8.5 and 10.5 GHz the PELDOR effect corresponding to the dipole interaction between the Mn cluster and YDrad was about 2.9 times larger than that achieved with a monochromatic pulse. In addition to the dipolar modulation, the nuclear modulation effects were observed. The effects could be suppressed by averaging the PELDOR trace over the time interval between the observation microwave pulses. The polychromatic excitation technique described will be useful for improving the PELDOR sensitivity in the measurements of long distances in biological samples, where the pair consists of a radical with a narrow EPR spectrum and slow phase relaxation, and a metal center that has a broad EPR spectrum and a short phase relaxation time.

  1. Surface roughness of polyvinyl siloxane impression materials following chemical disinfection, autoclave and microwave sterilization.

    Science.gov (United States)

    Al Kheraif, Abdulaziz Abdullah

    2013-05-01

    Autoclave sterilization and microwave sterilization has been suggested as the effective methods for the disinfection of elastomeric impressions, but subjecting elastomeric impressions to extreme temperature may have adverse effects on critical properties of the elastomers. To evaluate the effect of chemical disinfection as well as autoclave and microwave sterilization on the surface roughness of elastomeric impression materials. The surface roughness of five commercially available polyvinyl siloxane impression materials (Coltene President, Affinis Perfect impression, Aquasil, 3M ESPE Express and GC Exafast) were evaluated after subjecting them to chemical disinfection, autoclaving and microwave sterilization using a Talysurf Intra 50 instrument. Twenty specimens from each material were fabricated and divided into four equal groups, three experimental and one control (n=25). The differences in the mean surface roughness between the treatment groups were recorded and statistically analyzed. No statistically significant increase in the surface roughness was observed when the specimens were subjected to chemical disinfection and autoclave sterilization, increase in roughness and discoloration was observed in all the materials when specimens were subjected to microwave sterilization. Chemical disinfection did not have a significant effect but, since it is less effective, autoclave sterilization can be considered effective and autoclaving did not show any specimen discoloration as in microwave sterilization. Microwave sterilization may be considered when impressions are used to make diagnostic casts. A significant increase in surface roughness may produce rougher casts, resulting in rougher tissue surfaces for denture and cast restorations. Autoclave sterilization of vinyl polysiloxane elastomeric impressions for 5 minutes at 134°C at 20 psi may be considered an effective method over chemical disinfection and microwave sterilization, because chemical disinfection does

  2. Development of a diagnostic system for high power microwave (FEL) electric fields in the Microwave Tokamak Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Oda, T.; Takiyama, K. [Hiroshima Univ. (Japan). Faculty of Engineering; Odajima, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1992-12-31

    One of the most important diagnostics for the electron-cyclotron-frequency heating (ECH) experiments is to directly measure the spatial distribution of the microwave electric field in a plasma for understanding the absorption mechanism of the microwave in the plasma. We have developed a diagnostic system using laser-aided particle-probe spectroscopy (LAPPS) to observe the high electric field (>100 kV/cm) generated by a free electron laser (FEL) beam for the ECH study in the Microwave Tokamak Experiment (MTX) at the Lawrence Livermore National Laboratory. The principle of method and an outline of the diagnostic system have been presented. The diagnostic apparatus consists of a neutral helium beam, a dye laser exciting the neutral beam, and a spectroscopic system with originally designed collecting optics. Using the Stark effect we observe fluorescences induced by the forbidden transitions from the metastable levels of the helium atoms to obtain the electric field strength in the plasma. Similar spectroscopic measurements have been made of high frequency electric fields in plasmas, although the plasmas have quite lower densities and temperatures than the MTX plasma. The whole apparatus was assembled on a mock-up of the MTX torus at Japan Atomic Energy Research Institute at Tokai, and we have observed laser-induced fluorescences from the LAPPS helium beam. Measurements of beam intensity using Faraday cups and thermocouples have been also made. (author) 5 refs., 3 figs., 1 tab.

  3. A proposal for constraining initial vacuum by cosmic microwave background

    Science.gov (United States)

    Chandra, Debabrata; Pal, Supratik

    2018-01-01

    We propose a theoretical framework that can possibly constrain the initial vacuum by observation of the cosmic microwave background (CMB). With a generic vacuum without any particular choice a priori, thereby keeping both the Bogolyubov coefficients in the analysis, we compute observable parameters from two- and three-point correlation functions. We are thus left with constraining four model parameters from the two complex Bogolyubov coefficients. We also demonstrate a method of finding out the constraint relations between the Bogolyubov coefficients using the theoretical normalization condition and observational data of power spectrum and bispectrum from CMB. Finally, we discuss the possible pros and cons of the analysis.

  4. Spectral measurements of the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

  5. Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling of Liquids Occurs under Certain Conditions but is Mitigated by Stirring

    Directory of Open Access Journals (Sweden)

    Anthony Ferrari

    2015-12-01

    Full Text Available Temporary superheating and sustained nucleation-limited “superboiling” of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating and magnitude (of superheating and superboiling vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating.

  6. Electromagnetic and microwave absorbing properties of hollow ...

    Indian Academy of Sciences (India)

    Keywords. Nanomaterials; nanospheres; CVD; electric; magnetic; microwave absorption properties. 1. Introduction. In recent years, microwave absorbing materials have attracted considerable attention because it is an essential part of a stealthy defense system for all military platforms, either as aircraft, sea or land vehicles.

  7. Microwave synthesis and mechanical characterization of functionally ...

    Indian Academy of Sciences (India)

    Microwave synthesis and mechanical characterization of functionally graded material for applications in fusion devices ... compact with fine microstructure and good mechanical property has been synthesized by employing microwave heating method at a temperature of 800 °C and in a short processing time of 30 min.

  8. Microwave Accelerated Aza-Claisen Rearrangement

    Directory of Open Access Journals (Sweden)

    Eva Gajdošíková

    2008-11-01

    Full Text Available A study of microwave-induced and standard thermal Overman rearrangement of selected allylic trichloroacetimidates 1a-1f, 6-8 to the corresponding acetamides 2a-2f, 9-11 is reported. The microwave-assisted rearrangement of trifluoroacetimidate 13 is also described. Using this methodology, an efficient access to versatile allylic trihaloacetamides building synthons was established.

  9. An introduction to high power microwaves

    Science.gov (United States)

    Benford, James; Swegle, John

    1992-02-01

    The area of high power microwaves has emerged in recent years as a new technology allowing new applications and offering innovative approaches to existing applications. The great leap in microwave power levels has been driven by a mix of sources that either push conventional microwave device physics in new directions or employ altogether new interaction mechanisms. Running counter to the trend in conventional microwave electronics toward miniaturization with solid-state devices intrinsically limited in their peak power capability, high power microwave generation taps the immense power and energy reservoirs of modern intense relativistic electron beam technology. The term high power microwaves (HPM) is used to denote devices that exceed 100 MW in peak power and span the cm- and mm-wave range of frequencies between 1 and 300 GHz. This definition is arbitrary, but does cleanly divide the conventional microwave devices, which do not exceed 100 MW, from a collection of microwave-generating devices that have now reached powers as high as 15 GW.

  10. Microwave dielectric properties of nanostructured nickel ferrite

    Indian Academy of Sciences (India)

    Wintec

    ... microwave dielectric; co-precipitation. 1. Introduction. Ferrites find wide technological applications in making cores of audio frequency and high frequency transformers, coils (inductors), chokes, permanent magnets, magneto- optical displays, microwave absorbers, wave guides in the. GHz region and chlorine gas sensors ...

  11. Characteristics of microwave propagation in vapourised troposphere ...

    African Journals Online (AJOL)

    Microwave communication equipment design in temperate region may not be very suitable in the tropics because the characteristics of the troposphere as the medium of propagation differ ... The meteorological vertical data taken from radiosonde confirms evidence of super-refraction and ducting of the microwave signal.

  12. Prospects of microwave processing: An overview

    Indian Academy of Sciences (India)

    Administrator

    wave heating. In addition, microwave energy is being explored for the sintering of metal powders also. Ceramic and metal nanopowders have been sintered in microwave. Furthermore, initiatives ... is energy conversion rather than heat transfer. Since micro- .... present review paper provides an overview of the micro- wave ...

  13. Microwave bale moisture sensing: Field trial

    Science.gov (United States)

    A microwave moisture measurement technique was developed for moisture sensing of cotton bales after the bale press. The technique measures the propagation delay of a microwave signal that is transmitted through the cotton bale. This research conducted a field trial to test the sensor in a commercial...

  14. Microwave bale moisture sensing: Field trial continued

    Science.gov (United States)

    A microwave moisture measurement technique was developed at the USDA, ARS Cotton Production and Processing Research Unit for moisture sensing of cotton bales after the bale press. The technique measures the propagation delay of a microwave signal that is transmitted through the cotton bale. This res...

  15. Anisotropy of Wood in the Microwave Region

    Science.gov (United States)

    Ziherl, Sasa; Bajc, Jurij; Urankar, Bernarda; Cepic, Mojca

    2010-01-01

    Wood is transparent for microwaves and due to its anisotropic structure has anisotropic dielectric properties. A laboratory experiment that allows for the qualitative demonstration and quantitative measurements of linear dichroism and birefringence in the microwave region is presented. As the proposed experiments are based on the anisotropy (of…

  16. Microwave Properties of Hyaluronate Solutions Using a Resonant Microwave Cavity as a Probe.

    Science.gov (United States)

    Jani, Shirish Keshavlal

    1980-12-01

    Physiological functions of a biomacromolecule seem to be closely related to its molecular conformations. The knowledge of any conformational changes due to changes in its environment may lead to a proper understanding of its functions. Hyaluronic acid, a biomacromolecule with unusually high molecular weight and some important biological functions is the subject of the present work. The conformational changes in human umbilical cord hyaluronic acid molecules in various environments were observed by monitoring their dielectric response at microwave frequencies. A tunable resonant microwave cavity operated in the TE(,011) mode was used as a probe in monitoring the dielectric response of the hyaluronate solutions. Both the real and imaginary parts of complex dielectric constant and the loss tangent for the solutions were obtained by utilizing equations for perturbation of a resonant cavity. Dielectric changes at room temperature were observed in aqueous solutions of hyaluronic acid as a function of concentration ranging from 0 to 350 mg/ml. The data indicate the existence of ordered phases in hyaluronate solutions at selective concentrations; that is, the hyaluronate molecule exhibits lyotropic type transitions. Hyaluronate solutions at 1.5 and 3 mg/ml concetrations were studied at various pH in the range 6-8 and at constant ionic strength 0.1. The pH-dependent dielectric changes were observed in hyaluronate solutions at both these concentrations. A temperature-dependent transition in hyaluronate solution of 120 mg/ml concentration was observed at physiological temperature. It is shown that this temperature-dependent behavior can be related to the orientational polarizability term in the Debye theory of polar molecules in liquids.

  17. Multiband rectenna for microwave applications

    Science.gov (United States)

    Okba, Abderrahim; Takacs, Alexandru; Aubert, Hervé; Charlot, Samuel; Calmon, Pierre-François

    2017-02-01

    This paper reports a multiband rectenna (rectifier + antenna) suitable for the electromagnetic energy harvesting of the spill-over loss of microwave antennas placed on board of geostationary satellites. Such rectenna is used for powering autonomous wireless sensors for satellite health monitoring. The topology of the rectenna is presented. The experimental results demonstrate that the proposed compact rectenna can harvest efficiently the incident electromagnetic energy at three different frequencies that are close to the resonant frequencies of the cross-dipoles implemented in the antenna array. xml:lang="fr"

  18. Design of microwave active devices

    CERN Document Server

    Gautier , Jean-Luc

    2014-01-01

    This book presents methods for the design of the main microwave active devices. The first chapter focuses on amplifiers working in the linear mode. The authors present the problems surrounding narrowband and wideband impedance matching, stability, polarization and the noise factor, as well as specific topologies such as the distributed amplifier and the differential amplifier. Chapter 2 concerns the power amplifier operation. Specific aspects on efficiency, impedance matching and class of operation are presented, as well as the main methods of linearization and efficiency improvement. Freq

  19. Stochastic model in microwave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Ranfagni, A. [“Nello Carrara” Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Mugnai, D., E-mail: d.mugnai@ifac.cnr.it [“Nello Carrara” Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2011-11-28

    Further experimental results of delay time in microwave propagation are reported in the presence of a lossy medium (wood). The measurements show that the presence of a lossy medium makes the propagation slightly superluminal. The results are interpreted on the basis of a stochastic (or path integral) model, showing how this model is able to describe each kind of physical system in which multi-path trajectories are present. -- Highlights: ► We present new experimental results on electromagnetic “anomalous” propagation. ► We apply a path integral theoretical model to wave propagation. ► Stochastic processes and multi-path trajectories in propagation are considered.

  20. Thermodynamics of Water Superheated in the Microwave Oven

    Science.gov (United States)

    Erné, B. H.

    2000-10-01

    A simple visual demonstration is proposed that provokes thinking about the elementary thermodynamics of heating and boiling. Water is conveniently heated above its normal boiling point in a microwave oven in a glass microwave oven teapot. Water stops boiling soon after heating is interrupted, but subsequently added rough particles can still act as nucleation centers for a brief, spectacular burst of steam bubbles. The heat to make those steam bubbles obviously comes from the water itself, so that one can conclude that the boiling water was superheated, which is confirmed with a thermometer. Besides illustrating chemical thermodynamics, the demonstration also shows why safety precautions are usually taken in the laboratory to prevent superheating. Details of the observations are discussed by giving background on the nucleation of steam bubbles.

  1. Passive microwave remote sensing for sea ice research

    Science.gov (United States)

    1984-01-01

    Techniques for gathering data by remote sensors on satellites utilized for sea ice research are summarized. Measurement of brightness temperatures by a passive microwave imager converted to maps of total sea ice concentration and to the areal fractions covered by first year and multiyear ice are described. Several ancillary observations, especially by means of automatic data buoys and submarines equipped with upward looking sonars, are needed to improve the validation and interpretation of satellite data. The design and performance characteristics of the Navy's Special Sensor Microwave Imager, expected to be in orbit in late 1985, are described. It is recommended that data from that instrument be processed to a form suitable for research applications and archived in a readily accessible form. The sea ice data products required for research purposes are described and recommendations for their archival and distribution to the scientific community are presented.

  2. Microwave Field Effect on Polyphenolic Compounds from Aromatic Plants

    Directory of Open Access Journals (Sweden)

    Maria - Loredana Soran

    2016-03-01

    Full Text Available Nowadays, the use of mobile telephony and wire-less devices has become more demanding, generating electromagnetic radiations. Microwave radiation can affect the growth rate of plants. For this study, the aromatic plants i.e. parsley, celery, dill, basil, were chosen as irradiated plants. This study aims to investigate the effects of irradiation with microwave field on polyphenolic compounds from basil, celery and parsley.  The extracts were obtained by sonication. Quantitative analysis of polyphenolic compounds was performed by high performance liquid chromatography using an Altima C18 column. The elution was performed in gradient, with acetonitrile (eluent A and formic acid in water (1%, eluent B. It was observed that in the irradiated plants, the content of polyphenolic compounds was higher than in the controlled plant. This finding suggests that that plants were strongly influenced by stress due to electromagnetic fields.

  3. Bias characteristics of temperature and relative humidity retrieved by microwave radiometer in Naqu region over the Tibetan Plateau

    Science.gov (United States)

    Zhuang, W.

    2016-12-01

    Radiosonde is the most basic method to measure the atmospheric temperature and humidity profiles with very coarse temporal resolution (2-4 times per day for conventional observation). But multiple simultaneous profiles of temperature, humidity, and so on can be obtained in 2-3 minutes temporal resolution with the microwave radiometer. In the third Tibetan Plateau experiment of Atmospheric Scientific organized by the Chinese Academy of Meteorological Sciences, synergic observations by ground-based multi-band radars and other detection equipments were used to study the microphysical processes of cloud and precipitation in Naqu area on the Tibetan Plateau. In this paper, profiles of temperature and relative humidity retrieved by microwave radiometer in different observation modes (zenith observation and off-zenith observation modes) are compared with collocated radiosondes during the summer period from 2014 to 2015 in Naqu region for different weather conditions defined by the data of millimeter wave cloud radar and raindrop spectrum. Three methods to compare the observation between microwave radiometer and radiosonde are temporal-spatial precision matching method, nearest temporal matching method and average profile method. The results show that: 1. Average profile method has the minimum difference between microwave radiometer retrievals and collocated sounding observation. 2. Profiles of temperature and relative humidity retrieved by microwave radiometer under zenith observation model and collocated sounding observation are more consistent under the condition of non-precipitation cloud than other weather conditions (clear sky and precipitation cloud). 3. Compared to zenith observation mode, the retrievals from the off-zenith observation mode of the microwave radiometer has a reasonable accuracy against the sounding observation. 4. In contract with cloudy sky, the retrievals by microwave radiometer and the sounding observation has the highest bias under the weather

  4. Microwave chirality discrimination in enantiomeric liquids

    Science.gov (United States)

    Hollander, E.; Kamenetskii, E. O.; Shavit, R.

    2017-07-01

    Chirality discrimination is of fundamental interest in biology, chemistry, and metamaterial studies. In optics, near-field plasmon-resonance spectroscopy with superchiral probing fields is effectively applicable for analyses of large biomolecules with chiral properties. We show possibility for microwave near-field chirality discrimination analysis based on magnon-resonance spectroscopy. Newly developed capabilities in microwave sensing using magnetoelectric (ME) probing fields originated from multiresonance magnetic-dipolar-mode oscillations in quasi-2D yttrium-iron-garnet disks provide potential for unprecedented measurements of chemical and biological objects. We report on microwave near-field chirality discrimination for aqueous D- and L-glucose solutions. The shown ME-field sensing is addressed to deepen our understanding of microwave-biosystem interactions. It can also be important for an analysis and design of microwave chiral metamaterials.

  5. Quantum teleportation of propagating quantum microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Di Candia, R.; Felicetti, S.; Sanz, M. [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); Fedorov, K.G.; Menzel, E.P. [Bayerische Akademie der Wissenschaften, Walther-Meissner-Institut, Garching (Germany); Technische Universitaet Muenchen, Physik-Department, Garching (Germany); Zhong, L.; Deppe, F.; Gross, R. [Bayerische Akademie der Wissenschaften, Walther-Meissner-Institut, Garching (Germany); Technische Universitaet Muenchen, Physik-Department, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Marx, A. [Bayerische Akademie der Wissenschaften, Walther-Meissner-Institut, Garching (Germany); Solano, E. [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); Basque Foundation for Science, IKERBASQUE, Bilbao (Spain)

    2015-12-15

    Propagating quantum microwaves have been proposed and successfully implemented to generate entanglement, thereby establishing a promising platform for the realisation of a quantum communication channel. However, the implementation of quantum teleportation with photons in the microwave regime is still absent. At the same time, recent developments in the field show that this key protocol could be feasible with current technology, which would pave the way to boost the field of microwave quantum communication. Here, we discuss the feasibility of a possible implementation of microwave quantum teleportation in a realistic scenario with losses. Furthermore, we propose how to implement quantum repeaters in the microwave regime without using photodetection, a key prerequisite to achieve long distance entanglement distribution. (orig.)

  6. Applications of Graphene at Microwave Frequencies

    Directory of Open Access Journals (Sweden)

    M. Bozzi

    2015-09-01

    Full Text Available In view to the epochal scenarios that nanotechnology discloses, nano-electronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor devices. Since low dimensional (1D and 2D nano-structured materials exhibit unprecedented electro-mechanical properties in a wide frequency range, including radio-frequencies (RF, microwave nano-electronics provides an enormous and yet widely undiscovered opportunity for the engineering community. Carbon nano-electronics is one of the main research routes of RF/microwave nano-electronics. In particular, graphene has shown proven results as an emblematic protagonist, and a real solution for a wide variety of microwave electronic devices and circuits. This paper introduces graphene properties in the microwave range, and presents a paradigm of novel graphene-based devices and applications in the microwave/RF frequency range.

  7. A Microwave Thruster for Spacecraft Propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Chiravalle, Vincent P [Los Alamos National Laboratory

    2012-07-23

    This presentation describes how a microwave thruster can be used for spacecraft propulsion. A microwave thruster is part of a larger class of electric propulsion devices that have higher specific impulse and lower thrust than conventional chemical rocket engines. Examples of electric propulsion devices are given in this presentation and it is shown how these devices have been used to accomplish two recent space missions. The microwave thruster is then described and it is explained how the thrust and specific impulse of the thruster can be measured. Calculations of the gas temperature and plasma properties in the microwave thruster are discussed. In addition a potential mission for the microwave thruster involving the orbit raising of a space station is explored.

  8. Effect of different alcohols, gelatinizing times, calcination and microwave on characteristics of TiO2 nanoparticles synthesized by sol-gel method

    Science.gov (United States)

    Bahar, Mahmoud; Mozaffari, Masoud; Esmaeili, Sahar

    2017-03-01

    In this work, nanoparticles of titanium dioxide (TiO2) were synthesized by means of TiCl4 as precursor. Effects of alcohol type, calcination, gelatinizing time and microwave exposure on the particle size, morphology, crystallinity and particle phase are studied using XRD patterns and SEM images. Results showed that alcohols such as ethanol increased the particle size; calcination increased the particle size and improved the crystallinity of particles. Microwave exposure of particles resulted in smaller particles; adding water increased the impact of microwave. Effect of microwave exposure in rutile phase formation is also observed during this study.

  9. The DMRT-ML Model: Numerical Simulations of the Microwave Emission of Snowpacks Based on the Dense Media Radiative Transfer Theory

    Science.gov (United States)

    Brucker, Ludovic; Picard, Ghislain; Roy, Alexandre; Dupont, Florent; Fily, Michel; Royer, Alain

    2014-01-01

    Microwave radiometer observations have been used to retrieve snow depth and snow water equivalent on both land and sea ice, snow accumulation on ice sheets, melt events, snow temperature, and snow grain size. Modeling the microwave emission from snow and ice physical properties is crucial to improve the quality of these retrievals. It also is crucial to improve our understanding of the radiative transfer processes within the snow cover, and the snow properties most relevant in microwave remote sensing. Our objective is to present a recent microwave emission model and its validation. The model is named DMRT-ML (DMRT Multi-Layer), and is available at http:lgge.osug.frpicarddmrtml.

  10. Imaging Microwave and DC Magnetic Fields in a Vapor-Cell Rb Atomic Clock

    CERN Document Server

    Affolderbach, Christoph; Bandi, Thejesh; Horsley, Andrew; Treutlein, Philipp; Mileti, Gaetano

    2015-01-01

    We report on the experimental measurement of the DC and microwave magnetic field distributions inside a recently-developed compact magnetron-type microwave cavity, mounted inside the physics package of a high-performance vapor-cell atomic frequency standard. Images of the microwave field distribution with sub-100 $\\mu$m lateral spatial resolution are obtained by pulsed optical-microwave Rabi measurements, using the Rb atoms inside the cell as field probes and detecting with a CCD camera. Asymmetries observed in the microwave field images can be attributed to the precise practical realization of the cavity and the Rb vapor cell. Similar spatially-resolved images of the DC magnetic field distribution are obtained by Ramsey-type measurements. The T2 relaxation time in the Rb vapor cell is found to be position dependent, and correlates with the gradient of the DC magnetic field. The presented method is highly useful for experimental in-situ characterization of DC magnetic fields and resonant microwave structures,...

  11. Biocompatible Hollow Polydopamine Nanoparticles Loaded Ionic Liquid Enhanced Tumor Microwave Thermal Ablation in Vivo.

    Science.gov (United States)

    Tan, Longfei; Tang, Wenting; Liu, Tianlong; Ren, Xiangling; Fu, Changhui; Liu, Bo; Ren, Jun; Meng, Xianwei

    2016-05-11

    Tumor microwave thermal therapy (MWTT) has attracted more attention because of the minimal damage to body function, convenient manipulation and low complications. Herein, a novel polydopamine (PDA) nanoparticle loading ionic liquids (ILs/PDA) as microwave susceptible agent is introduced for enhancing the selectivity and targeting of MWTT. ILs/PDA nanocomposites have an excellent microwave heating efficiency under an ultralow microwave power irradiation. Encouraging antitumor effect was observed when tumor bearing mice received ILs/PDA nanoparticles by intravenous injection and only single microwave irradiation. PDA nanoparticles with gold nanoparticles in core were constructed for tumor targeting study by ICP-MS and about 15% PDA nanoparticles were founded in tumor. Furthermore, the cytotoxicity and acute toxicity study in vivo of PDA showed the excellent biocompatibility of ILs/PDA nanocomposites. In addition, the degradation of ILs/PDA nanocomposites in simulated body fluid illustrated the low potential hazard when they entered the blood. The emergence of PDA as a novel and feasible platform for cancer thermal therapy will promote the rapid development of microwave therapy in clinics.

  12. Survival of Listeria spp. on raw whole chickens cooked in microwave ovens.

    Science.gov (United States)

    Farber, J M; D'Aoust, J Y; Diotte, M; Sewell, A; Daley, E

    1998-11-01

    The prevalence of microwave ovens in North American homes has increased dramatically within the last decade. Although microwave ovens are primarily used for reheating of foods, they are now more commonly being applied to the cooking of raw foods. Although cooking of raw foods, according to manufacturers' instructions targets an organoleptically acceptable end product, the process does not address the microbiological safety of the cooked food. Seventeen microwave ovens from various commercial suppliers were used to cook naturally contaminated whole raw broilers ( 1.8 kg) according to manufacturers' instructions. Temperature probes (six per chicken) were used to measure the temperature of chickens immediately after cooking and during the holding period. Of 81 Listeria-positive raw broilers and 93 raw roasters, 1 (1.2%) and 9 (9.7%), respectively, yielded viable Listeria spp. after microwave cooking. Of these, two were undercooked (visual inspection), one was over the maximum weight stipulated by the oven manufacturer and another one was over the maximum weight and undercooked. A significantly greater proportion of contaminated cooked birds was observed with roasters than with broilers, where for one of these contaminated roasters, the temperature at all six measured sites was > or = 87 degrees C. Most of the postcook Listeria-positive birds were associated with 2 of the 17 microwave ovens. Factors such as wattage, cavity size, and the presence or absence of a turntable seemingly did not play a significant role in the survival of Listeria spp. in microwave-cooked chicken. However, the general inability of microwave ovens to uniformly heat chicken carcasses was noted. In order to promote greater safety of microwave-cooked foods, general recommendations for consumers are provided.

  13. Evaluation of the effects of low energetic microwave irradiation on anaerobic digestion.

    Science.gov (United States)

    Bastiaens, Bert; Van den Broeck, Rob; Appels, Lise; Dewil, Raf

    2017-11-01

    The present study investigates the effects of microwave irradiation on the performance of anaerobic digestion processes. A first set of experiments is performed to distinguish the upper limit of the applied energy levels. Secondly, the effects of these treatments on the performance of the digestion process are evaluated in 3 experimental setups: (i) monitoring the acetic acid degradation, (ii) performing a biological methane potential (BMP) assay and (iii) conducting a specific methanogenic activity (SMA) test. The solubilisation experiment reveals a limited degree of disintegration of anaerobic biomass up to a microwave treatment of 10000 kJ/kg TS. Above this threshold value the soluble COD level started to rise, with up to 350% at 30000 kJ/kg TS regardless of the microwave output power. Because solubilisation of the biomass increases the easily degradable content, this would lead to false observations regarding increased activity. Therefore, solubilisation is minimized by limiting the microwave treatment to a maximum of 6000 kJ/kg TS during the second part of the experiments. Monitoring the degradation of acetic acid after a low intensity microwave treatment, reveals that microwave irradiation shortens the lag phase, e.g., from 21 to 3 h after a microwave treatment of 1000 kJ/kg TS at 100 W. However most treatments also result in a decrease of the maximum degradation and of the degradation rate of acetic acid. BMP assays are performed to evaluate the activity and performance of the entire anaerobic community. Every treatment results in a decreased biogas production potential and decreased biogas production rate. Moreover, each treatment induced an increase of the lag phase. The SMA experiments show no influence of the microwave irradiation in terms of biogas or methane production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Dielectric properties, optimum formulation and microwave baking conditions of chickpea cakes.

    Science.gov (United States)

    Alifakı, Yaşar Özlem; Şakıyan, Özge

    2017-03-01

    The aim of this study was to correlate dielectric properties with quality parameters, and to optimize cake formulation and baking conditions by response surface methodology. Weight loss, color, specific volume, hardness and porosity were evaluated. The samples with different DATEM (0.4, 0.8 and 1.2%) and chickpea flour concentrations (30, 40 and 50%) were baked in microwave oven at different power (300, 350, 400 W) and baking times (2.50, 3.0, 3.50 min). It was found that microwave power showed significant effect on color, while baking time showed effect on weight loss, porosity, hardness, specific volume and dielectric properties. Emulsifier level affected porosity, specific volume and dielectric constant. Chickpea flour level affected porosity, color, hardness and dielectric properties of cakes. The optimum microwave power, baking time, DATEM level and chickpea flour level were found as 400 W, 2.84 min, 1.2% and 30%, respectively. The comparison between conventionally baked and the microwave baked cakes at optimum points showed that color difference, weight loss, specific volume and porosity values of microwave baked cakes were less than those of conventionally baked cakes, on the other hand, hardness values were higher. Moreover, a negative correlation between dielectric constant and porosity, and weight loss values were detected for microwave baked samples. A negative correlation between dielectric loss factor and porosity was observed. These correlations indicated that quality characteristics of a microwave baked cake sample can be assessed from dielectric properties. These correlations provides understanding on the behavior of food material during microwave processing.

  15. Microwave disinfection of complete dentures contaminated in vitro with selected bacteria.

    Science.gov (United States)

    Dovigo, Lívia Nordi; Pavarina, Ana Cláudia; Ribeiro, Daniela Garcia; de Oliveira, Juliana Aparecida; Vergani, Carlos Eduardo; Machado, Ana Lucia

    2009-10-01

    This study evaluated the effectiveness of microwave irradiation for disinfection of simulated complete dentures. Seventy dentures were fabricated in a standardized procedure, subjected to ethylene oxide sterilization, individually inoculated (10(7) cfu/mL) with Staphylococcus aureus (n = 20), Pseudomona aeruginosa (n = 20), and Bacillus subtilis (n = 30) and incubated for 24 hours at 37 degrees C. After that, 40 dentures were selected for microwaving. For each microorganism, 10 dentures were submitted to microwave irradiation at 650 W for 3 minutes. In addition, 10 dentures contaminated with B. subtilis were irradiated for 5 minutes. Thirty non-microwaved dentures (n = 10 for each bacteria) were used as positive controls. Replicate aliquots (25 microL) of suspensions were plated at dilutions of 10(-3) to 10(-6) on plates of selective media appropriate for each organism. After incubation (37 degrees C for 48 hours), colonies were counted (cfu/mL). TSB beakers with the microwaved dentures were incubated at 37 degrees C for a further 7 days to verify long-term disinfection. The data were statistically analyzed by the Kruskal-Wallis test (alpha= 0.05). No evidence of growth was observed at 48 hours for S. aureus and P. aeruginosa on plates, and no turbidity was visible in the TSB beakers of these specimens after 7 days of incubation. Dentures contaminated with B. subtilis and irradiated for 3 minutes produced microbial growth on six plates and turbidity on all TSB beakers. Microwaving for 5 minutes resulted in survival of B. subtilis in two plates and two beakers. Microwave irradiation for 3 minutes at 650 W produced sterilization of complete dentures contaminated with S. aureus and P. aeruginosa. Dentures contaminated with B. subtilis were disinfected by microwave irradiation after 3 and 5 minutes at 650 W.

  16. Cryogenic pulsed inductive microwave magnetometer

    Science.gov (United States)

    Kos, A. B.; Nibarger, J. P.; Lopusnik, R.; Silva, T. J.; Celinski, Z.

    2003-05-01

    A cryogenic pulsed inductive microwave magnetometer is used to characterize the switching dynamics in thin-film magnetic materials at low temperatures and microwave frequencies. The system is contained inside a 20-cm-diam ultrahigh vacuum chamber and cooled by a cryopump that allows measurements between 20 and 350 K. A temperature controller regulates the sample temperature using two silicon diodes as sensors. Applied magnetic fields of up to 36 kA/m (450 Oe) are generated by a four-pole, water-cooled electromagnet with independent control of each axis. Magnetic switching in the sample is driven by high-speed current step pulses in a coplanar waveguide structure with the sample placed in a flip-chip configuration. A 20 GHz sampling oscilloscope is used to record the dynamics of the magnetic reorientation. The switching dynamics are given for a 10-nm-thick Ni-Fe film at 30 K in response to a 1 kA/m field step.

  17. Response surface optimisation for activation of bentonite with microwave irradiation

    Directory of Open Access Journals (Sweden)

    Rožić Ljiljana S.

    2011-01-01

    Full Text Available In this study, the statistical design of the experimental method was applied on the acid activation process of bentonite with microwave irradiation. The influence of activation parameters (time, acid normality and microwave heating power on the selected process response of the activated bentonite samples was studied. The specific surface area was chosen for the process response, because the chemical, surface and structural properties of the activated clay determine and limit its potential applications. The relationship of various process parameters with the specific surface area of bentonite was examined. A mathematical model was developed using a second-order response surface model (RSM with a central composite design incorporating the above mentioned process parameters. The mathematical model developed helped in predicting the variation in specific surface area of activated bentonite with time (5-21 min, acid normality (2-7 N and microwave heating power (63-172 W. The calculated regression models were found to be statistically significant at the required range and presented little variability. Furthermore, high values of R2 (0.957 and R2 (adjusted (0.914 indicate a high dependence and correlation between the observed and the predicted values of the response. These high values also indicate that about 96% of the result of the total variation can be explained by this model. In addition, the model shows that increasing the time and acid normality improves the textural properties of bentonites, resulting in increased specific surface area. This model also can be useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g-1 was achieved with an acid normality of 5.2 N, activation time of 7.38 min and microwave power of 117 W. Acid activation of bentonite was found to occur faster with microwave irradiation than with conventional heating. Microwave

  18. Study of microwave components for an electron cyclotron resonance ...

    Indian Academy of Sciences (India)

    Keywords. Microwave system; microwave studio software; network analyser; electron cyclotron resonance ion source. ... of ∼13 eV was obtained. This article describes various aspects of the microwave system including design, fabrication, characterization and performance studies of the microwave components.

  19. Microwave Cooking: Knowledge, Attitudes, and Practices of California Foods Teachers.

    Science.gov (United States)

    Stalder, Laura D.; And Others

    1990-01-01

    A survey of 500 California secondary foods teachers (172 responses) indicated their understanding of microwave cooking principles and techniques and positive attitudes toward microwave cooking and safety. A majority used microwave instruction in their classrooms, although many indicated a need for ovens and microwave educational materials. (SK)

  20. All-sky radiance simulation of Megha-Tropiques SAPHIR microwave ...

    Indian Academy of Sciences (India)

    Incorporation of cloud- and precipitation-affected radiances from microwave satellite sensors in data .... equation is solved by computing the multiple scat- .... product of satellite estimates (TRMM) and rain guage observations (IMD) at 0.5. ◦ resolution, accu- mulated for 24 hrs. The observed rainfall (top panel of figure 1) ...

  1. Applications of passive microwave data to monitor inundated areas and model stream flow

    NARCIS (Netherlands)

    Shang, H.

    2017-01-01

    The observation of surface water bodies in all weather conditions and better knowledge about inundation patterns are important for water resource management and flood early warning. Microwave radiometers at 37 GHz were applied to observe and study the inundation pattern in large subtropical

  2. Accelerated staining technique using kitchen microwave oven.

    Science.gov (United States)

    Mukunda, Archana; Narayan, T V; Shreedhar, Balasundhari; Shashidhara, R; Mohanty, Leeky; Shenoy, Sadhana

    2015-01-01

    Histopathological diagnosis of specimens is greatly dependent on good sample preparation and staining. Both of these processes is governed by diffusion of fluids and dyes in and out of the tissue, which is the key to staining. Diffusion of fluids can be accelerated by the application of heat that reduces the time of staining from hours to the minute. We modified an inexpensive model of kitchen microwave oven for staining. This study is an attempt to compare the reliability of this modified technique against the tested technique of routine staining so as to establish the kitchen microwave oven as a valuable diagnostic tool. Sixty different tissue blocks were used to prepare 20 pairs of slides for 4 different stains namely hematoxylin and eosin, Van Gieson's, 0.1% toluidine blue and periodic acid-Schiff. From each tissue block, two bits of tissues were mounted on two different slides. One slide was stained routinely, and the other stained inside a microwave. A pathologist evaluated the stained slides and the results so obtained were analyzed statistically. Microwave staining considerably cut down the staining time from hours to seconds. Microwave staining showed no loss of cellular and nuclear details, uniform-staining characteristics and was of excellent quality. The cellular details, nuclear details and staining characteristics of microwave stained tissues were better than or equal to the routine stained tissue. The overall quality of microwave-stained sections was found to be better than the routine stained tissue in majority of cases.

  3. Continuous microwave flow synthesis of mesoporous hydroxyapatite.

    Science.gov (United States)

    Akram, Muhammad; Alshemary, Ammar Z; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O; Hussain, Rafaqat

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca(2+) ion released in SBF solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Low-field microwave absorption in pulse laser deposited FeSi thin film

    Energy Technology Data Exchange (ETDEWEB)

    Gavi, H. [Department of Physics, SARCHI Chair in Carbon Technology and Materials, Institute of Applied Materials, University of Pretoria, Pretoria 0028 (South Africa); Ngom, B.D. [Groupe d Laboratoires de Physique des Solid et des Materiaux, Faculte deSciences et Techniques, Universite Cheikh Anta de Dakar, BP 25114 Dakar-Fann, Daka 16996 (Senegal); Institut National de la Recherche Scientifique Centre-Energie Materiaux, Telecommunications 1650, Boulevard Lionel Boulet Varennes (Quebec), Canada J3X 1S2 (Canada); Beye, A.C. [Groupe d Laboratoires de Physique des Solid et des Materiaux, Faculte deSciences et Techniques, Universite Cheikh Anta de Dakar, BP 25114 Dakar-Fann, Daka 16996 (Senegal); Strydom, A.M. [Department of Physics, University of Johannesburg, Johannesburg 2006 (South Africa); Srinivasu, V.V., E-mail: vallavs@unisa.ac.za [Department of Physics, University of South Africa, Pretoria 0003 (South Africa); Chaker, M. [Institut National de la Recherche Scientifique Centre-Energie Materiaux, Telecommunications 1650, Boulevard Lionel Boulet Varennes (Quebec), Canada J3X 1S2 (Canada); Manyala, N., E-mail: ncholu.manyala@up.ac.za [Department of Physics, SARCHI Chair in Carbon Technology and Materials, Institute of Applied Materials, University of Pretoria, Pretoria 0028 (South Africa)

    2012-03-15

    Low field microwave absorption (LFMA) measurements at 9.4 GHz (X-band), were carried out on pulse laser deposited (PLD) polycrystalline B20 cubic structure FeSi thin film grown on Si (111) substrate. The LFMA properties of the films were investigated as a function of DC field, temperature, microwave power and the orientation of DC field with respect to the film surface. The LFMA signal is very strong when the DC field is parallel to the film surface and vanishes at higher angles. The LFMA signal strength increases as the microwave power is increased. The LFMA signal disappears around 340 K, which can be attributed to the disappearance of ferromagnetic state well above room temperature in these films. We believe that domain structure evolution in low fields, which in turn modifies the low field permeability as well as the anisotropy, could be the origin of the LFMA observed in these films. The observation of LFMA opens the possibility of the FeSi films to be used as low magnetic field sensors in the microwave and rf frequency regions. - Highlights: Black-Right-Pointing-Pointer B20 crystalline FeSi thin film shows low field microwave absorption. Black-Right-Pointing-Pointer Usual ferromagnic resonance typical of magnetic materials is observed in FeSi film. Black-Right-Pointing-Pointer FeSi film can be used for low magnetic field sensors.

  5. A field evaluation of a satellite microwave rainfall sensor network

    Science.gov (United States)

    Caridi, Andrea; Caviglia, Daniele D.; Colli, Matteo; Delucchi, Alessandro; Federici, Bianca; Lanza, Luca G.; Pastorino, Matteo; Randazzo, Andrea; Sguerso, Domenico

    2017-04-01

    An innovative environmental monitoring system - Smart Rainfall System (SRS) - that estimates rainfall in real-time by means of the analysis of the attenuation of satellite signals (DVB-S in the microwave Ku band) is presented. Such a system consists in a set of peripheral microwave sensors placed on the field of interest, and connected to a central processing and analysis node. It has been developed jointly by the University of Genoa, with its departments DITEN and DICCA and the Genoese SME "Darts Engineering Srl". This work discusses the rainfall intensity measurements accuracy and sensitivity performance of SRS, based on preliminary results from a field comparison experiment at the urban scale. The test-bed is composed by a set of preliminary measurement sites established from Autumn 2016 in the Genoa (Italy) municipality and the data collected from the sensors during a selection of rainfall events is studied. The availability of point-scale rainfall intensity measurements made by traditional tipping-bucket rain gauges and radar areal observations allows a comparative analysis of the SRS performance. The calibration of the reference rain gauges has been carried out at the laboratories of DICCA using a rainfall simulator and the measurements have been processed taking advantage of advanced algorithms to reduce counting errors. The experimental set-up allows a fine tuning of the retrieval algorithm and a full characterization of the accuracy of the rainfall intensity estimates from the microwave signal attenuation as a function of different precipitation regimes.

  6. Reconfigurable metasurface aperture for security screening and microwave imaging

    Science.gov (United States)

    Sleasman, Timothy; Imani, Mohammadreza F.; Boyarsky, Michael; Pulido-Mancera, Laura; Reynolds, Matthew S.; Smith, David R.

    2017-05-01

    Microwave imaging systems have seen growing interest in recent decades for applications ranging from security screening to space/earth observation. However, hardware architectures commonly used for this purpose have not seen drastic changes. With the advent of metamaterials a wealth of opportunities have emerged for honing metasurface apertures for microwave imaging systems. Recent thrusts have introduced dynamic reconfigurability directly into the aperture layer, providing powerful capabilities from a physical layer with considerable simplicity. The waveforms generated from such dynamic metasurfaces make them suitable for application in synthetic aperture radar (SAR) and, more generally, computational imaging. In this paper, we investigate a dynamic metasurface aperture capable of performing microwave imaging in the K-band (17.5-26.5 GHz). The proposed aperture is planar and promises an inexpensive fabrication process via printed circuit board techniques. These traits are further augmented by the tunability of dynamic metasurfaces, which provides the dexterity necessary to generate field patterns ranging from a sequence of steered beams to a series of uncorrelated radiation patterns. Imaging is experimentally demonstrated with a voltage-tunable metasurface aperture. We also demonstrate the aperture's utility in real-time measurements and perform volumetric SAR imaging. The capabilities of a prototype are detailed and the future prospects of general dynamic metasurface apertures are discussed.

  7. Microwave study of superconducting Sn films above and below percolation

    Energy Technology Data Exchange (ETDEWEB)

    Beutel, Manfred H.; Ebensperger, Nikolaj G.; Thiemann, Markus; Untereiner, Gabriele; Dressel, Martin; Scheffler, Marc [1. Physikalisches Institut, Stuttgart Univ. (Germany)

    2016-07-01

    The electronic properties of superconducting Sn films (T{sub c} ∼ 3.7 K) change significantly when lowering the film thickness down to a few nm, in particular at the percolation threshold. The low energy electrodynamics of such Sn samples can be probed via microwave spectroscopy, e.g. with superconducting stripline resonators. We have deposited Sn films by thermal evaporation, ranging in thickness between 38 nm and 842 nm, and we characterized their morphology by AFM. We use superconducting Pb stripline resonators to probe the microwave response of Sn films at temperatures from 7.5 K down to 1.5 K in a frequency range between 1 GHz and 20 GHz. The measured quality factor of the resonators decreases with increasing temperature due to increasing losses. As a function of the sample thickness we observe three regimes with significantly different properties: Samples below percolation exhibit dielectric properties with negligible losses, demonstrating that macroscopic current paths are required for appreciable dynamical conductivity of Sn at GHz frequencies. Thick Sn films, on the other hand, lead to low-loss resonances above and below T{sub c} of Sn, but in an intermediate thickness regime, just above percolation, the metallic state of the Sn films is too lossy for resonator operation whereas the superconducting state only has low microwave losses.

  8. Temporal behavior of microwave sheath-voltage combination plasma

    CERN Document Server

    Kar, Satyananda; Raja, Laxminarayan L

    2015-01-01

    Microwave sheath-Voltage combination Plasma (MVP) is a high density plasma source and can be used as a suitable plasma processing device (e.g., ionized physical vapor deposition). In the present report, the temporal behavior of an argon MVP sustained along a direct-current biased Ti rod is investigated. Two plasma modes are observed, one is an "oxidized state" (OS) at the early time of the microwave plasma and the other is "ionized sputter state" (ISS) at the later times. Transition of the plasma from OS to ISS, results a prominent change in the visible color of the plasma, resulting from a significant increase in the plasma density, as measured by a Langmuir probe. In the OS, plasma is dominated by Ar ions and the density is order 10^11 cm^-3. In the ISS, metal ions from the Ti rod contribute significantly to the ion composition and higher density plasma (10^12 cm^-3) is produced. Nearly uniform high density plasma along the length of the Ti rod is produced at very low input microwave powers (around 30 W). O...

  9. Constant-dose microwave irradiation of insect pupae

    Science.gov (United States)

    Olsen, Richard G.

    Pupae of the yellow mealworm Tenebrio molitor L. were subjected to microwave irradiation for 1.5-24 hours at power density levels adjusted to produce a total dosage of approximately 1123 J/g in each insect for every experiment. Insects without visible blemishes were exposed in a standing wave irradiation system such that half of them were exposed in the plane of maximum electric field (E field) and the other half were exposed in the plane of maximum magnetic field (H field). Both E field and H field insects exhibited nearly the same specific absorption rate (SAR) for pupal orientation parallel to the magnetic field vector at 5.95 GHz. Irradiations were conducted both with and without the use of a ventilating fan to control the temperature rise in the irradiation chamber. Abnormal development as a result of the microwave exposure was seen only in the high-power, short-duration experiment without chamber ventilation. This result suggests a thermal interaction mechanism for explanation of observed microwave-induced abnormalities. A study of the time course of the average temperature rise in the irradiated insects indicates that teratological effects for this configuration have a temperature threshold of approximately 40°C.

  10. Microwave Plasma Hydrogen Recovery System

    Science.gov (United States)

    Atwater, James; Wheeler, Richard, Jr.; Dahl, Roger; Hadley, Neal

    2010-01-01

    A microwave plasma reactor was developed for the recovery of hydrogen contained within waste methane produced by Carbon Dioxide Reduction Assembly (CRA), which reclaims oxygen from CO2. Since half of the H2 reductant used by the CRA is lost as CH4, the ability to reclaim this valuable resource will simplify supply logistics for longterm manned missions. Microwave plasmas provide an extreme thermal environment within a very small and precisely controlled region of space, resulting in very high energy densities at low overall power, and thus can drive high-temperature reactions using equipment that is smaller, lighter, and less power-consuming than traditional fixed-bed and fluidized-bed catalytic reactors. The high energy density provides an economical means to conduct endothermic reactions that become thermodynamically favorable only at very high temperatures. Microwave plasma methods were developed for the effective recovery of H2 using two primary reaction schemes: (1) methane pyrolysis to H2 and solid-phase carbon, and (2) methane oligomerization to H2 and acetylene. While the carbon problem is substantially reduced using plasma methods, it is not completely eliminated. For this reason, advanced methods were developed to promote CH4 oligomerization, which recovers a maximum of 75 percent of the H2 content of methane in a single reactor pass, and virtually eliminates the carbon problem. These methods were embodied in a prototype H2 recovery system capable of sustained high-efficiency operation. NASA can incorporate the innovation into flight hardware systems for deployment in support of future long-duration exploration objectives such as a Space Station retrofit, Lunar outpost, Mars transit, or Mars base. The primary application will be for the recovery of hydrogen lost in the Sabatier process for CO2 reduction to produce water in Exploration Life Support systems. Secondarily, this process may also be used in conjunction with a Sabatier reactor employed to

  11. Features of Changing Microwave Radiation from Loaded Rock in Elastic Phase

    Science.gov (United States)

    Wu, Lixin; Mao, Wenfei; Huang, Jianwei; Liu, Shanjun; Xu, Zhongying

    2017-04-01

    Since the discovery of satellite infrared anomaly occurred before some earthquake by Russian geo-scientists in 1980's, both satellite remote sensing on seismic activities and experimental infrared detection on rock physics in process of rock loading were undertaken in many counties including China, Japan, Europe nations and United States. Infrared imager and spectrum instruments were applied to detect the changed infrared radiation from loaded rock to fracturing, which lead to the development of Remote Sensing Rock Mechanics. However, the change of microwave radiation from loaded rock was not so much studied, even if abnormal changes of microwave brightness temperature (MBT) preceding some large earthquakes were observed by satellite sensors such as AMSR-E on boarded Aqua. To monitor rock hazards, seismic activities, and to make earthquake precautions by via of microwave detection or microwave remote sensing, it is fairly demanded to explore the laws of microwave radiation variation with changed stress and to uncover the rock physics. We developed a large scale rock loading system with capability of 500 tons and 10 tons of load, respectively, at two horizontal loading head, and designed a group of microwave detectors in C, K, and Ka bands. To investigate the changed microwave radiation from loaded granite and sandstone in its elastics deformation phase, the first horizontal stress was circularly applied on rock samples of size 10×30×60cm3 at a constant second horizontal stress, and the changes microwave radiation was detected by the detectors hanged overhead the rock sample. The experiments were conducted outdoor at nighttime to keep off environmental radiation and to simulate the satellite observation conditions in background of cool sky. The first horizontal stress and the microwave radiations were synchronically detected and recorded. After reducing the random noise of detected microwave signals with wavelet method, we found the MBT increase with stress rising

  12. Microwave-Assisted Resolution of α-Lipoic Acid Catalyzed by an Ionic Liquid Co-Lyophilized Lipase

    Directory of Open Access Journals (Sweden)

    Ning Liu

    2015-05-01

    Full Text Available The combination of the ionic liquid co-lyophilized lipase and microwave irradiation was used to improve enzyme performance in enantioselective esterification of α-lipoic acid. Effects of various reaction conditions on enzyme activity and enantioselectivity were investigated. Under optimal condition, the highest enantioselectivity (E = 41.2 was observed with a high enzyme activity (178.1 μmol/h/mg when using the ionic liquid co-lyophilized lipase with microwave assistance. Furthermore, the ionic liquid co-lyophilized lipase exhibited excellent reusability under low power microwave.

  13. Microwave line of sight link engineering

    CERN Document Server

    Angueira, Pablo

    2012-01-01

    A comprehensive guide to the design, implementation, and operation of line of sight microwave link systems The microwave Line of Sight (LOS) transport network of any cellular operator requires at least as much planning effort as the cellular infrastructure itself. The knowledge behind this design has been kept private by most companies and has not been easy to find. Microwave Line of Sight Link Engineering solves this dilemma. It provides the latest revisions to ITU reports and recommendations, which are not only key to successful design but have changed dramatically in

  14. Heating of matter by microwaves without convection

    OpenAIRE

    Drašković, Draško

    2012-01-01

    This thesis considers heating of matter by means of microwaves. The most common device that uses micro waves for the heating of matter is the microwave oven. Because of the microwave ovens ubiquity and accessibility there are many articles that address the way it works and in how it heats matter. However, it appears that articles contradict each other in their claims that the heating of the matter is either from the inside or from the outside. What actually means »heating the material in the...

  15. RF and microwave coupled-line circuits

    CERN Document Server

    Mongia, R K; Bhartia, P; Hong, J; Gupta, K C

    2007-01-01

    This extensively revised edition of the 1999 Artech House classic, RF and Microwave Coupled-Line Circuits, offers you a thoroughly up-to-date understanding of coupled line fundamentals, explaining their applications in designing microwave and millimeter-wave components used in today's communications, microwave, and radar systems. The Second Edition includes a wealth of new material, particularly relating to applications. You find brand new discussions on a novel simple design technique for multilayer coupled circuits, high pass filters using coupled lines, software packages used for filter des

  16. Microwave filters and circuits contributions from Japan

    CERN Document Server

    Matsumoto, Akio

    1970-01-01

    Microwave Filters and Circuits: Contributions from Japan covers ideas and novel circuits used to design microwave filter that have been developed in Japan, as well as network theory into the field of microwave transmission networks. The book discusses the general properties and synthesis of transmission-line networks; transmission-line filters on the image-parameter basis; and experimental results on a class of transmission-line filter constructed only with commensurate TEM lossless transmission lines. The text describes lines constants, approximation problems in transmission-line networks, as

  17. Effects of microwave radiation on living tissues

    Energy Technology Data Exchange (ETDEWEB)

    Surrell, J.A.; Alexander, R.C.; Cohle, S.D.; Lovell, F.R. Jr.; Wehrenberg, R.A.

    1987-08-01

    Prompted by an alleged case of child abuse resulting from microwave oven burns and the discovery of one other case, an animal model was chosen to explore microwave burn characteristics upon living, perfusing tissue. Anesthetized piglets were exposed to radiation from a standard household microwave oven for varying lengths of time, sufficient to result in full-thickness skin and visceral burns. Characteristic burn patterns were grossly identified. Biopsies studied with both light and electron microscopy demonstrated a pattern of relative layered tissue sparing. Layered tissue sparing is characterized by burned skin and muscle, with relatively unburned subcutaneous fat between these two layers. These findings have important forensic and patient care implications.

  18. Microwave Spectroscopy of Cold Rubidium Atoms

    OpenAIRE

    Entin, V. M.; Ryabtsev, I. I.

    2004-01-01

    The effect of microwave radiation on the resonance fluorescence of a cloud of cold $^{85}Rb$ atoms in a magnetooptical trap is studied. The radiation frequency was tuned near the hyperfine splitting frequency of rubidium atoms in the 5S ground state. The microwave field induced magnetic dipole transitions between the magnetic sublevels of the 5S(F=2) and 5S(F=3) states, resulting in a change in the fluorescence signal. The resonance fluorescence spectra were recorded by tuning the microwave r...

  19. Cesium microwave emission without population inversion.

    Science.gov (United States)

    Levi, F; Godone, A; Vanier, J

    1999-01-01

    The use of coherent population trapping (CPT) for the realization of a Cs coherent microwave emitter without population inversion is described. Preliminary experimental results are reported regarding the radio frequency spectrum of the emitted microwave radiation, the emission profile width, and the transient behavior of the output power. This new approach, based on the coherence properties of the laser radiation, allows the implementation of a microwave frequency standard where the linear light shift is absent and the thermal noise limit for the frequency instability is below 10(-12) for an integration time of 1 s.

  20. Perturbing microwave beams by plasma density fluctuations

    Directory of Open Access Journals (Sweden)

    Köhn Alf

    2017-01-01

    Full Text Available The propagation of microwaves across a turbulent plasma density layer is investigated with full-wave simulations. To properly represent a fusion edge-plasma, drift-wave turbulence is considered based on the Hasegawa-Wakatani model. Scattering and broadening of a microwave beam whose amplitude distribution is of Gaussian shape is studied in detail as a function of certain turbulence properties. Parameters leading to the strongest deterioration of the microwave beam are identified and implications for existing experiments are given.