WorldWideScience

Sample records for thermal uv emission

  1. Time-resolved x-ray line emission studies of thermal transport in multiple beam uv-irradiated targets

    International Nuclear Information System (INIS)

    Jaanimagi, P.A.; Henke, B.L.; Delettrez, J.; Richardson, M.C.

    1984-01-01

    Thermal transport in spherical targets irradiated with multiple, nanosecond duration laser beams, has been a topic of much discussion recently. Different inferences on the level of thermal flux inhibition have been drawn from plasma velocity and x-ray spectroscopic diagnostics. We present new measurements of thermal transport on spherical targets made through time-resolved x-ray spectroscopic measurements of the progress of the ablation surface through thin layers of material on the surface of the target. These measurements, made with 6 and 12 uv (351 nm) nanosecond beams from OMEGA, will be compared to previous thermal transport measurements. Transparencies of the conference presentation are given

  2. UV line emission of symbiotic stars

    International Nuclear Information System (INIS)

    Nussbaumer, H.

    1982-01-01

    General characteristics of emission line spectra from symbiotic stars are outlined. Data from some special line ratios in the 1000 A - 3000 A range, and others connecting the visual and the far UV lines are presented, and their application to symbiotic stars is discussed. Integrated fractional abundances for ions easily observed in the far UV are given to facilitate abundance determinations for nebular conditions. It is found that the physical conditions of the regions emitting the emission line spectra differ considerably among different symbiotic stars. (Auth.)

  3. UV time-dependent emission in SY Muscae

    International Nuclear Information System (INIS)

    Michalitsianos, A.G.; Kafatos, M.

    1982-01-01

    Ultraviolet spectra acquired with the International Ultraviolet Explorer (IUE) of SY Mus = HD 10036 on 20 September 1980 and 11 June 1981 indicate a substantial enhancement of UV emission over a nine month period. The general UV flux level appears to have increased by approximately one order of magnitude between the first and second observing epochs. The strong ultraviolet continuum evident throughout the entire IUE spectral range lambdalambda1200-3200 A on 11 June 1981 is closely approximated by a star with Tsub(eff) = 40,000 K, where previously on 20 September 1980 the continuum distribution presented a more complex structure that is possibly explained by a combination of thermal emission from an early type main sequence star, and nebular recombination emission (Michalitsianos et al. 1981). (Auth.)

  4. The composite nature of the thermoluminescence UV emission of quartz

    Energy Technology Data Exchange (ETDEWEB)

    Fasoli, Mauro, E-mail: mauro.fasoli@mater.unimib.it [Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, via R. Cozzi 55, I-20125 Milano (Italy); INFN, Sezione di Milano Bicocca, Piazza della Scienza 1, I-20126 Milano (Italy); Martini, Marco [Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, via R. Cozzi 55, I-20125 Milano (Italy); INFN, Sezione di Milano Bicocca, Piazza della Scienza 1, I-20126 Milano (Italy)

    2016-05-15

    The radioluminescence (RL) spectra of three types of quartz have been compared to those obtained from wavelength resolved thermally stimulated luminescence (TSL) measurements. A detailed numerical deconvolution into Gaussian components allowed to identify which of the bands are involved in either types of luminescence processes. The blue “A band” at 2.51 eV was confirmed to dominate both RL and TSL spectra in samples exposed to prolonged irradiation. The UV emission of the 110 °C TSL peak was found to be composite. Analogously to what previously reported for RL spectra, an annealing at 500 °C for 10 min induced a strong enhancement of the “C band” at 3.42 eV. This effect was particularly evident in natural and pre-irradiated quartz. A second intense UV component, the “M band” at 3.7 eV, was found to contribute to both TSL and RL spectra of samples annealed at 1000 °C for 10 min. A further broad UV emission seems to be involved only in RL emission but not in the TSL one.

  5. UV-induced N2O emission from plants

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2014-01-01

    investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

  6. Symbiotic star UV emission and theoretical models

    International Nuclear Information System (INIS)

    Kafatos, M.

    1982-01-01

    Observations of symbiotic stars in the far UV have provided important information on the nature of these objects. The canonical spectrum of a symbiotic star, e.g. RW Hya, Z And, AG Peg, is dominated by strong allowed and semiforbidden lines of a variety of at least twice ionized elements. Weaker emission from neutral and singly ionized species is also present. A continuum may or may not be present in the 1200 - 2000 A range but is generally present in the range 2000 - 3200 A range. The suspected hot subdwarf continuum is seen in some cases in the range 1200 - 2000 A (RW Hya, AG Peg, SY Mus). The presence of an accretion disk is difficult to demonstrate and to this date the best candidate for accretion to a main sequence star remains CI Cyg. A number of equations have been derived by the author that can yield the accretion parameters from the observable quantities. Boundary layer temperatures approximately 10 5 K and accretion rates approximately > 10 -5 solar masses/yr are required for accreting main sequence companions. To this date, though, most of the symbiotics may only require the presence of a approximately 10 5 K hot subdwarf. (Auth.)

  7. UV-induced carbon monoxide emission from living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2013-01-01

    The global burden of carbon monoxide (CO) is rather uncertain. In this paper we address the potential for UV-induced CO emission by living terrestrial vegetation surfaces. Real-time measurements of CO concentrations were made with a cavity enhanced laser spectrometer connected in closed loop...... to either an ecosystem chamber or a plant-leaf scale chamber. Leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation as well as the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature......, indicating an abiotic process. The emission of CO in response to the UV-component of natural solar radiation was also evident at the ecosystem scale....

  8. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  9. Laboratory technique for quantitative thermal emissivity ...

    Indian Academy of Sciences (India)

    Emission of radiation from a sample occurs due to thermal vibration of its .... Quantitative thermal emissivity measurements of geological samples. 393. Figure 1. ...... tral mixture modeling: A new analysis of rock and soil types at the Viking ...

  10. UV emissions from low energy artificial light sources.

    Science.gov (United States)

    Fenton, Leona; Moseley, Harry

    2014-01-01

    Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. IR emission and UV extinction in two open clusters

    International Nuclear Information System (INIS)

    Hackwell, J.A.; Hecht, J.H.

    1989-01-01

    Recent models of interstellar extinction have shown the importance of understanding both the UV and IR properties of interstellar dust grains. IRAS data have shown variations in 60 and 100 micron emissions presumably due to the presence of IR cirrus, while recent observations in the UV by Fitzpatrick and Massa have identified components in the UV extinction curve which vary in different star regions. A Draine and Anderson model connects these results by proposing that different size variations in interstellar grains would cause distinct changes in both the IR emission and the UV extinction. In order to test this model it is necessary to make observations in well defined locations away from peculiar extinction regions. In the infrared this means looking away from the galactic plane so as to limit non-local sources of IR radiation. Two open clusters that are out of the galactic plane and which contain a number of late B and early A stars suitable for UV extinction studies, and whose IRAS data show variations in the 60/100 micron ratio were studied. Based on the Drain and Anderson model, variations were expected in their UV extinction curves that correlate with the IR cirrus emission

  12. UV emission properties of thulium-doped fluorozirconate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Piramidowicz, R., E-mail: r.piramidowicz@elka.pw.edu.p [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Telekomunikacja Polska Research and Development Centre, Obrzezna 7, 02-691 Warsaw (Poland); Bok, A.; Klimczak, M.; Malinowski, M. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland)

    2009-12-15

    In this work, we present our latest results on UV emission in bulk ZBLAN glasses doped with thulium ions, broadening knowledge of the short-wavelength optical properties of this system. We examined a set of samples with different activator concentrations (2500, 10,000, 25,000 and 50,000 ppm) in respect of absorption and short-wavelength emission properties. The concentration-dependant spectra of UV emission from the {sup 1}I{sub 6}+{sup 3}P{sub 0} and {sup 1}D{sub 2} levels and fluorescence dynamics profiles have been recorded and carefully examined under direct (one-photon) excitation, enabling discussion of fluorescence quenching mechanisms and determination of appropriate cross-relaxation rates. According to authors' best knowledge, the three-photon red-to-UV up-conversion has been reported for the first time under excitation of a laser diode.

  13. Luminescent emission of LiF: Mg, Ti exposed to UV radiation

    International Nuclear Information System (INIS)

    Estrada G, A.; Castano M, V.M.; Cruz Z, E.; Garcia F, F.

    2002-01-01

    It was investigated the luminescent emission stimulated by heat (Tl) of LiF: Mg, Ti crystals which were exposed to UV radiation coming from a mercury lamp. Since this crystal depends on the thermal history, it has been used a thermal treatment consisting of a baking at 380 C during one hour for each reading and they were irradiated with UV. The brilliance curves between 5 and 840 minutes of exposure in the face of UV light were obtained. An important loss in the response, starting from 150 minutes of irradiation was observed. Also the relative intensity of the brilliance curve decay when the crystals being stored in darkness and room temperature conditions, which is according to the results in the literature about. (Author)

  14. Luminescent emission of LiF: Mg, Ti exposed to UV radiation; Emision luminiscente del LiF: Mg, Ti expuesto a la radiacion UV

    Energy Technology Data Exchange (ETDEWEB)

    Estrada G, A. [Estudiante de Facultad de Ciencias, UNAM, Circuito Exterior, 04500 Mexico D.F. (Mexico); Castano M, V.M. [Centro de Fisica Aplicada y Tecnologia Avanzada, UNAM, Campus Juriquilla, Queretaro (Mexico); Cruz Z, E.; Garcia F, F. [Instituto de Ciencias Nucleares UNAM, A.P. 70-543 Mexico D.F. (Mexico)

    2002-07-01

    It was investigated the luminescent emission stimulated by heat (Tl) of LiF: Mg, Ti crystals which were exposed to UV radiation coming from a mercury lamp. Since this crystal depends on the thermal history, it has been used a thermal treatment consisting of a baking at 380 C during one hour for each reading and they were irradiated with UV. The brilliance curves between 5 and 840 minutes of exposure in the face of UV light were obtained. An important loss in the response, starting from 150 minutes of irradiation was observed. Also the relative intensity of the brilliance curve decay when the crystals being stored in darkness and room temperature conditions, which is according to the results in the literature about. (Author)

  15. Thermal Degradation and Damping Characteristic of UV Irradiated Biopolymer

    Directory of Open Access Journals (Sweden)

    Anika Zafiah M. Rus

    2015-01-01

    Full Text Available Biopolymer made from renewable material is one of the most important groups of polymer because of its versatility in application. In this study, biopolymers based on waste vegetable oil were synthesized and cross-link with commercial polymethane polyphenyl isocyanate (known as BF. The BF was compressed by using hot compression moulding technique at 90°C based on the evaporation of volatile matter, known as compress biopolymer (CB. Treatment with titanium dioxide (TiO2 was found to affect the physical property of compressed biopolymer composite (CBC. The characterization of thermal degradation, activation energy, morphology structure, density, vibration, and damping of CB were determined after UV irradiation exposure. This is to evaluate the photo- and thermal stability of the treated CB or CBC. The vibration and damping characteristic of CBC samples is significantly increased with the increasing of UV irradiation time, lowest thickness, and percentages of TiO2 loading at the frequency range of 15–25 Hz due to the potential of the sample to dissipate energy during the oscillation harmonic system. The damping property of CBC was improved markedly upon prolonged exposure to UV irradiation.

  16. Thermal transport measurements of uv laser irradiated spherical targets

    International Nuclear Information System (INIS)

    Jaanimagi, P.A.; Delettrez, J.; Henke, B.L.; Richardson, M.C.

    1985-01-01

    New measurements are presented of thermal transport in spherical geometry using time-resolved x-ray spectroscopy. We determine the time dependence of the mass ablation rate m(dot) by following the progress of the ablation surface through thin layers of material embedded at various depths below the surface of the target. These measurements made with 6 and 12 uv (351 nm) beams from OMEGA are compared to previous thermal transport data and are in qualitative agreement with detailed LILAC hydrodynamic code simulations which predict a sharp decrease in m(dot) after the peak of the laser pulse. Non-uniform laser irradiation of the target results in the anomalously high values of m(dot) measured in these experiments

  17. Defect studies in quartz: Composite nature of the blue and UV emissions

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Marco, E-mail: m.martini@unimib.it [Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, via R. Cozzi 55, I-20125 Milano (Italy); INFN, Sezione di Milano Bicocca, Piazza della Scienza 1, I-20126 Milano (Italy); Fasoli, Mauro; Villa, Irene [Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, via R. Cozzi 55, I-20125 Milano (Italy)

    2014-05-01

    Quartz is an extremely diffused natural luminescence dosimeter. Thanks to the presence of traps and luminescence centres, its TSL and OSL (Thermally and Optically Stimulated Luminescence) properties have been extensively exploited. Quartz is then used for archaeological and geological dating and is one of the most useful materials for accident dosimetry. Many luminescence emissions are known to be present in the OSL and TSL of quartz. Three main emission bands are always reported, as the red, blue and UV bands, centred at around 650, 470, and 360–380 nm, respectively. Although the assignment of the luminescence emissions to specific defect centres in quartz is still undefined, a thorough analysis of the radioluminescence emissions and their response to irradiation and thermal treatments turned out to be very useful in understanding many features. Specifically, the presence of the same emission bands in natural and synthetic quartz and their dependence on the presence of extrinsic impurities is a common characteristic. The main impurities involve Al ions substituting Si ones and charge compensated by nearby either alkali ions, H{sup +}, or a hole. The emission spectra dynamics evidenced in our experiment confirm the role of Al-related centres in the luminescence properties of quartz. From the measurements presented in this paper the composite nature of the “blue” emission is confirmed. Two bands labelled as A at 2.5 eV and B at 2.8 eV contribute to the emission in this region, their behaviour being different as a function of irradiation. More complex is the picture in the UV region, where, besides the already detected C and D bands at 3.4 eV and 3.9 eV, respectively, two further emissions have been detected at 3.1 eV and 3.7 eV. Despite both the 3.4 eV and the 3.7 eV bands are shown to be affected by thermal treatments, the annealing temperature dependence of their intensity is markedly different. In fact, whereas the C band intensity, at 3.4 eV, increases

  18. Defect studies in quartz: Composite nature of the blue and UV emissions

    International Nuclear Information System (INIS)

    Martini, Marco; Fasoli, Mauro; Villa, Irene

    2014-01-01

    Quartz is an extremely diffused natural luminescence dosimeter. Thanks to the presence of traps and luminescence centres, its TSL and OSL (Thermally and Optically Stimulated Luminescence) properties have been extensively exploited. Quartz is then used for archaeological and geological dating and is one of the most useful materials for accident dosimetry. Many luminescence emissions are known to be present in the OSL and TSL of quartz. Three main emission bands are always reported, as the red, blue and UV bands, centred at around 650, 470, and 360–380 nm, respectively. Although the assignment of the luminescence emissions to specific defect centres in quartz is still undefined, a thorough analysis of the radioluminescence emissions and their response to irradiation and thermal treatments turned out to be very useful in understanding many features. Specifically, the presence of the same emission bands in natural and synthetic quartz and their dependence on the presence of extrinsic impurities is a common characteristic. The main impurities involve Al ions substituting Si ones and charge compensated by nearby either alkali ions, H + , or a hole. The emission spectra dynamics evidenced in our experiment confirm the role of Al-related centres in the luminescence properties of quartz. From the measurements presented in this paper the composite nature of the “blue” emission is confirmed. Two bands labelled as A at 2.5 eV and B at 2.8 eV contribute to the emission in this region, their behaviour being different as a function of irradiation. More complex is the picture in the UV region, where, besides the already detected C and D bands at 3.4 eV and 3.9 eV, respectively, two further emissions have been detected at 3.1 eV and 3.7 eV. Despite both the 3.4 eV and the 3.7 eV bands are shown to be affected by thermal treatments, the annealing temperature dependence of their intensity is markedly different. In fact, whereas the C band intensity, at 3.4 eV, increases after

  19. UV-induced carbon monoxide emission from sand and living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2012-01-01

    The global burden of carbon monoxide, CO, is rather uncertain. In this paper we address the potential of UV-induced CO emission by terrestrial surfaces. Real-time measurements of [CO] were made with a cavity enhanced laser connected in closed loop to either an ecosystem chamber or a leaf scale...... chamber. Sand and leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation and the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature, indicating an abiotic process. The emission of CO...... in response to the UV-component of natural solar radiation was also evident at the ecosystem scale. When scaled to the global level, the UV-induced emission of CO by the major types of terrestrial surfaces, living leaves and soil (here represented by sand), amounts up to 28 Tg yr−1. This source has...

  20. Aftereffect of UV excitation on the ZnS electroluminescent emission

    International Nuclear Information System (INIS)

    Maxia, V.; Muntoni, C.; Murgia, M.

    1980-01-01

    The initial a.c. electroluminescent (EL) emission of ZnS(Cu) previously excited with UV light has been studied. The experiments showed that the EL build-up is made more swift by the preceding UV excitation. This result is ascribed to space charge produced by UV excitation which affects the exchange of electrons between lattice and EL defects. (author)

  1. Thermally stimulated exoelectron emission from solid Xe

    International Nuclear Information System (INIS)

    Khyzhniy, I.V.; Grigorashchenko, O.N.; Savchenko, E.V.; Ponomarev, A.N.; Bondybey, V.E.

    2007-01-01

    Thermally-stimulated emission of exoelectrons and photons from solid Xe pre-irradiated by low-energy electrons were studied. A high sensitivity of thermally-stimulated luminescence (TSL) and thermally-stimulated exoelectron emission (TSEE) to sample prehistory was demonstrated. It was shown that electron traps in unannealed samples are characterized by much broader distribution of trap levels in comparison with annealed samples and their concentration exceeds in number that in annealed samples. Both phenomena, TSL and TSEE, were found to be triggered by release of electrons from the same kind of traps. The data obtained suggest a competition between two relaxation channels: charge recombination and electron transport terminated by TSL and TSEE. It was found that TSEE predominates at low temperatures while at higher temperatures TSL prevails. An additional relaxation channel, a photon-stimulated exoelectron emission pre-irradiated solid Xe, was revealed

  2. FAR-UV EMISSION PROPERTIES OF FR1 RADIO GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Danforth, Charles W.; Stocke, John T.; France, Kevin; Begelman, Mitchell C. [Department of Astrophysical and Planetary Sciences, University of Colorado, 391-UCB, Boulder, CO 80309 (United States); Perlman, Eric, E-mail: danforth@colorado.edu [Department of Physics and Space Sciences, Florida Institute of Technology, 150 W. University Boulevard, Melbourne, FL 32901 (United States)

    2016-11-20

    The power mechanism and accretion geometry for low-power FR 1 radio galaxies are poorly understood in comparison to those for Seyfert galaxies and QSOs. In this paper, we use the diagnostic power of the Ly α recombination line observed using the Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope ( HST ) to investigate the accretion flows in three well-known, nearby FR 1s: M87, NGC 4696, and Hydra A. The Ly α emission line’s luminosity, velocity structure, and the limited knowledge of its spatial extent provided by COS are used to assess conditions within a few parsecs of the supermassive black hole in these radio-mode active galactic nuclei. We observe strong Ly α emission in all three objects with total luminosity similar to that seen in BL Lacertae objects. M87 shows a complicated emission-line profile in Ly α , which varies spatially across the COS aperture and possibly temporally over several epochs of observation. In both NGC 4696 and M87, the Ly α luminosities ∼10{sup 40} erg s{sup -1} are closely consistent with the observed strength of the ionizing continuum in Case B recombination theory and with the assumption of a near-unity covering factor. It is possible that the Ly α -emitting clouds are ionized largely by beamed radiation associated with the jets. Long-slit UV spectroscopy can be used to test this hypothesis. Hydra A and the several BL Lac objects studied in this and previous papers have Ly α luminosities larger than M87 but their extrapolated, nonthermal continua are so luminous that they overpredict the observed strength of Ly α , a clear indicator of relativistic beaming in our direction. Given their substantial space density (∼4 × 10{sup -3} Mpc{sup -3}), the unbeamed Lyman continuum radiation of FR 1s may make a substantial minority contribution (∼10%) to the local UV background if all FR 1s are similar to M87 in ionizing flux level.

  3. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    Energy Technology Data Exchange (ETDEWEB)

    Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Barman, Travis S., E-mail: shkolnik@lowell.edu, E-mail: barman@lpl.arizona.edu [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2014-10-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t {sup –1}. Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  4. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    International Nuclear Information System (INIS)

    Shkolnik, Evgenya L.; Barman, Travis S.

    2014-01-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t –1 . Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  5. UV, blue and red upconversion emission in Tm3+ doped Y2O3 phosphor

    International Nuclear Information System (INIS)

    Pandey, Anurag; Kaushal Kumar; Rai, Vineet Kumar

    2012-01-01

    Optimized solution combustion route has been adopted to prepare Tm 3+ doped Y 2 O 3 phosphor. The X-ray diffraction analysis of the doped phosphor for getting the structural information has been performed. Intense UV, blue and red emissions exhibiting narrow band have been monitored using 980 nm diode laser excitation. The origin of UV, blue and red upconversion emissions has been explained based on the available data. (author)

  6. Emission Control Technologies for Thermal Power Plants

    Science.gov (United States)

    Nihalani, S. A.; Mishra, Y.; Juremalani, J.

    2018-03-01

    Coal thermal power plants are one of the primary sources of artificial air emissions, particularly in a country like India. Ministry of Environment and Forests has proposed draft regulation for emission standards in coal-fired power plants. This includes significant reduction in sulphur-dioxide, oxides of nitrogen, particulate matter and mercury emissions. The first step is to evaluate the technologies which represent the best selection for each power plant based on its configuration, fuel properties, performance requirements, and other site-specific factors. This paper will describe various technology options including: Flue Gas Desulfurization System, Spray Dryer Absorber (SDA), Circulating Dry Scrubber (CDS), Limestone-based Wet FGD, Low NOX burners, Selective Non Catalytic Reduction, Electrostatic Precipitator, Bag House Dust Collector, all of which have been evaluated and installed extensively to reduce SO2, NOx, PM and other emissions. Each control technology has its advantages and disadvantages. For each of the technologies considered, major features, potential operating and maintenance cost impacts, as well as key factors that contribute to the selection of one technology over another are discussed here.

  7. Isoprenoids emission in Stipa tenacissima L.: Photosynthetic control and the effect of UV light

    International Nuclear Information System (INIS)

    Guidolotti, Gabriele; Rey, Ana; Medori, Mauro; Calfapietra, Carlo

    2016-01-01

    Fluxes of CO_2 and isoprenoids were measured for the first time in Stipa tenacissima L (alfa grass), a perennial tussock grass dominant in the driest areas of Europe. In addition, we studied how those fluxes were influenced by environmental conditions, leaf ontogeny and UV radiation and compared emission rates in two contrasting seasons: summer when plants are mostly inactive and autumn, the growing season in this region. Leaf ontogeny significantly affected both photosynthesis and isoprenoids emission. Isoprene emission was positively correlated with photosynthesis, although a low isoprene emission was detected in brown leaves with a net carbon loss. Moreover, leaves with a significant lower photosynthesis emitted only monoterpenes, while at higher photosynthetic rates also isoprene was produced. Ambient UV radiation uncoupled photosynthesis and isoprene emission. It is speculated that alfa grass represent an exception from the general rules governing plant isoprenoid emitters. - Highlights: • Stipa tenacissima L. is a grass emitting either monoterpenes and isoprene. • The emission has reasonable rates even in senescent leaves. • Isoprene emission is positively correlated with CO_2 assimilation. • Ambient UV radiation uncouples photosynthesis and isoprene emission. • Leaves with lower photosynthetic rates emit only monoterpenes. - We proved for the first time that alfa grass emit both isoprene and monoterpene, and we provide some innovative aspects about the UV effect and the behavior of Stipa tenacissima.

  8. [Investigation of multi-wavelength effect during the measurement of UV-enhanced film's emission spectrum].

    Science.gov (United States)

    Liu, Meng; Ni, Zheng-ji; Zhang, Da-wei; Huang, Yuan-shen; Zhuang, Song-lin

    2009-09-01

    The UV-responsive detector is a dual-use device for civilian and military after the laser and IR-responsive sensors. Typical image sensor coated with a layer of down-convert frequency thin film on it's photosurface to enhance UV response is the key technology of enhancing UV-response. The UV-enhanced thin film was made in the experimental laboratory using the Zn2SiO4:Mn phosphor by spin coating method. Two peaks at 520 and 560 nm respectively in the emission spectrum of the UV-enhanced film were found by SP1702 spectrograph when the excitation wavelength was 260 and 280 nm. The peaks were found in the process of experiment of measuring and counting the quantum efficiency of UV-enhanced thin film. But the light peaks at 520 and 560 nm are not the emission light peaks by the exciting light of 260 and 280 nm. The reason why the light at 520 and 560 nm is not the emission light was analyzed based on the measurement principle of grating spectrograph. The reasons for the multi-wavelength of light overlaps during the measurement of emission spectrum were also discussed. And the equipment used to separate the overlapped different wavelengths was designed, which will be used to resolve the problem of the overlap of multi-wavelength.

  9. Thermal helix-coil transition in UV irradiated collagen from rat tail tendon.

    Science.gov (United States)

    Sionkowska, A; Kamińska, A

    1999-05-01

    The thermal helix-coil transition in UV irradiated collagen solution, collagen film and pieces of rat tail tendon (RTT) were compared. Their thermal stability's were determined by differential scanning calorimeter (DSC) and by viscometric measurements. The denaturation temperatures of collagen solution, film and pieces of RTT were different. The helix-coil transition occur near 40 degrees C in collagen solution, near 112 degrees C in collagen film, and near 101 degrees C in pieces of RTT. After UV irradiation the thermal helix-coil transition of collagen samples were changed. These changes depend on the degree of hydratation.

  10. Two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films

    International Nuclear Information System (INIS)

    Xu, Linhua; Zheng, Gaige; Zhao, Lilong; Pei, Shixin

    2015-01-01

    Ag-doped ZnO thin films were prepared by a sol–gel method. The structural, morphological and optical properties of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis and photoluminescence spectra. The results show that the Ag in the ZnO thin films annealed at 500 °C for 1 h substitutes for Zn and exists in the form of Ag + ion (Ag Zn ) while the Ag in the ZnO thin films without a post-annealing mainly exists in the form of simple substance (Ag 0 ). The incorporation of Ag indeed can improve the ultraviolet emission of ZnO thin films and suppress the visible emissions at the same time. However, the mechanisms on the ultraviolet emission enhancement in the annealed and unannealed Ag-doped ZnO thin films are very different. As for the post-annealed Ag-doped ZnO thin films, the UV emission enhancement maybe mainly results from more electron–hole pairs (excitons) due to Ag-doping while for the unannealed Ag-doped ZnO thin films; the UV emission enhancement is attributed to the resonant coupling between exciton emission in ZnO and localized surface plasmon in Ag nanoparticles. - Highlights: • Ag-doped ZnO thin films have been prepared by the sol–gel method. • Ag-doping can enhance ultraviolet emission of ZnO thin films and depress the visible emissions at the same time. • There are two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films. • The UV emission enhancement from the resonant coupling between excitonic emissions and localized surface plasmon in Ag nanoparticle is very attractive

  11. Uranium plasma emission coefficient in the visible and near UV.

    Science.gov (United States)

    Mack, J. M., Jr.; Usher, J. L.; Schneider, R. T.; Campbell, H. D.

    1971-01-01

    Measurements of the specific emission coefficient in the near ultra-violet and visible region of a uranium arc plasma are reported. Spatial unfolding of the intensity profile is used to determine the emission coefficient in the spectral range of 2000 A to 6000 A. The uranium partial pressure is estimated to range between .001 and .01 atmosphere, and the corresponding temperature range is 5000 - 10,000 K.

  12. Radioactive emission from thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, K [New South Wales Univ., Kensington (Australia). Dept. of Applied Mathematics

    1981-07-01

    Radioactive hazards of the emissions and wastes of thermal power plants arising from fuel impurities of uranium and thorium are discussed. The hazard due to radioactive emission is calculated for an average Australian bituminous coal which contains 2 ppm of U and 2.7 ppm of Th. When the dust removal efficiency of a coal-fired power plant is 99%, the radioactive hazard is greater than that of a nuclear reactor of the same electrical output. After 500 years the radioactive toxicity of the coal waste will be higher than that of fission products of a nuclear reactor and after 2,000 years it will exceed the toxicity of all the nuclear wastes including actinides. The results of a recent calculation are shown, according to which the radioactive hazard of a coal-fired power plant to the public is from several hundred to several tens of thousands of times higher than that of a total fuel cycle of plutonium. It is found that in some regions, such as Japan, the hazard due to /sup 210/Po through seafood could be considerable.

  13. Thermally emissive sensing materials for chemical spectroscopy analysis

    Science.gov (United States)

    Poole, Zsolt; Ohodnicki, Paul R.

    2018-05-08

    A sensor using thermally emissive materials for chemical spectroscopy analysis includes an emissive material, wherein the emissive material includes the thermally emissive materials which emit electromagnetic radiation, wherein the electromagnetic radiation is modified due to chemical composition in an environment; and a detector adapted to detect the electromagnetic radiation, wherein the electromagnetic radiation is indicative of the chemical interaction changes and hence chemical composition and/or chemical composition changes of the environment. The emissive material can be utilized with an optical fiber sensor, with the optical fiber sensor operating without the emissive material probed with a light source external to the material.

  14. X-Ray, EUV, UV and Optical Emissivities of Astrophysical Plasmas

    Science.gov (United States)

    Raymond, John C.; West, Donald (Technical Monitor)

    2000-01-01

    This grant primarily covered the development of the thermal X-ray emission model code called APEC, which is meant to replace the Raymond and Smith (1977) code. The new code contains far more spectral lines and a great deal of updated atomic data. The code is now available (http://hea-www.harvard.edu/APEC), though new atomic data is still being added, particularly at longer wavelengths. While initial development of the code was funded by this grant, current work is carried on by N. Brickhouse, R. Smith and D. Liedahl under separate funding. Over the last five years, the grant has provided salary support for N. Brickhouse, R. Smith, a summer student (L. McAllister), an SAO predoctoral fellow (A. Vasquez), and visits by T. Kallman, D. Liedahl, P. Ghavamian, J.M. Laming, J. Li, P. Okeke, and M. Martos. In addition to the code development, the grant supported investigations into X-ray and UV spectral diagnostics as applied to shock waves in the ISM, accreting black holes and white dwarfs, and stellar coronae. Many of these efforts are continuing. Closely related work on the shock waves and coronal mass ejections in the solar corona has grown out of the efforts supported by the grant.

  15. A Non-thermal Pulsed X-Ray Emission of AR Scorpii

    Science.gov (United States)

    Takata, J.; Hu, C.-P.; Lin, L. C. C.; Tam, P. H. T.; Pal, P. S.; Hui, C. Y.; Kong, A. K. H.; Cheng, K. S.

    2018-02-01

    We report the analysis result of UV/X-ray emission from AR Scorpii, which is an intermediate polar (IP) composed of a magnetic white dwarf and an M-type star, with the XMM-Newton data. The X-ray/UV emission clearly shows a large variation over the orbit, and their intensity maximum (or minimum) is located at the superior conjunction (or inferior conjunction) of the M star orbit. The hardness ratio of the X-ray emission shows a small variation over the orbital phase and shows no indication of the absorption by an accretion column. These properties are naturally explained by the emission from the M star surface rather than that from the accretion column on the white dwarf’s (WD) star, which is similar to usual IPs. Additionally, the observed X-ray emission also modulates with the WD’s spin with a pulse fraction of ∼14%. The peak position is aligned in the optical/UV/X-ray band. This supports the hypothesis that the electrons in AR Scorpii are accelerated to a relativistic speed and emit non-thermal photons via the synchrotron radiation. In the X-ray bands, evidence of the power-law spectrum is found in the pulsed component, although the observed emission is dominated by the optically thin thermal plasma emissions with several different temperatures. It is considered that the magnetic dissipation/reconnection process on the M star surface heats up the plasma to a temperature of several keV and also accelerates the electrons to the relativistic speed. The relativistic electrons are trapped in the WD’s closed magnetic field lines by the magnetic mirror effect. In this model, the observed pulsed component is explained by the emissions from the first magnetic mirror point.

  16. UV induced photoluminescence and thermally stimulated luminescence of ThO2:Tb3+ phosphor

    International Nuclear Information System (INIS)

    Godbole, S.V.; Nagpal, J.S.; Page, A.G.

    2000-01-01

    Thorium oxide doped with trivalent terbium ions offers itself as a novel phosphor with its photo- and thermally-stimulated luminescence (PL and TSL) characteristics showing a marked change on sustained exposure to 254 and 365 nm ultraviolet (UV) radiation. The reduction in luminescence intensity of Tb 3+ ions, on irradiation with 254 nm photons and subsequent restoration on exposure to 365 nm, has been correlated with the complimentary behaviour in UV-induced TSL. These changes are, in turn, ascribed to inter-configurational (f-d) transitions and e-h formation and recombination processes. UV radiation induced TSL output increases linearly with incident UV radiant energy at a constant radiation flux; however, for a fixed exposure, TSL output increases with increase in radiant flux

  17. Salt-embedded carbon nanodots as a UV and thermal stable fluorophore for light-emitting diodes

    International Nuclear Information System (INIS)

    Kim, Tak H.; Wang, Fu; McCormick, Paul; Wang, Lianzhou; Brown, Chris; Li, Qin

    2014-01-01

    UV and thermal stable, photoluminescent carbon dots (CDs) prepared by embedding CDs in ionic salt crystals such as NaCl, KCl, KBr are demonstrated. The salt crystal embedding matrix does not interfere with CDs strong emission, and provides effective protection to CDs from the environment. The degradation of 20% of the initial luminescence intensity of salt-encapsulated CDs (S-CDs) is 15 times slower under UV and 6 times slower under heat compared to that of CDs in silica matrix. We also demonstrate that the S-CDs can be applied as a color-converting phosphor for typical GaN UV light emitting diodes (LEDs) with significant improvements in stability as well as processability. - Highlights: • Carbon dots can be uniformly embedded in ionic salt crystals via crystallization. • Salt crystals provide oxygen-tight matrices for protecting carbon dots from degradations. • Salt-embedded carbon dots can be applied as a stable color-converting phosphor in LEDs

  18. Salt-embedded carbon nanodots as a UV and thermal stable fluorophore for light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tak H. [Queensland Micro- and Nano-Technology Centre, Griffith University, Nathan, QLD 4111 (Australia); Environmental Engineering, Griffith University, QLD 4111 (Australia); Wang, Fu [Institute of Physiology, University of Freiburg, Hermann-Herder-Street 7, 79104 Freiburg (Germany); McCormick, Paul [School of Mechanical and Chemical Engineering, The University of Western Australia, WA 2009 (Australia); Wang, Lianzhou [School of Chemical Engineering, The University of Queensland, QLD 4072 (Australia); Brown, Chris [Queensland Micro- and Nano-Technology Centre, Griffith University, Nathan, QLD 4111 (Australia); Li, Qin, E-mail: qin.li@griffith.edu.au [Queensland Micro- and Nano-Technology Centre, Griffith University, Nathan, QLD 4111 (Australia); Environmental Engineering, Griffith University, QLD 4111 (Australia)

    2014-10-15

    UV and thermal stable, photoluminescent carbon dots (CDs) prepared by embedding CDs in ionic salt crystals such as NaCl, KCl, KBr are demonstrated. The salt crystal embedding matrix does not interfere with CDs strong emission, and provides effective protection to CDs from the environment. The degradation of 20% of the initial luminescence intensity of salt-encapsulated CDs (S-CDs) is 15 times slower under UV and 6 times slower under heat compared to that of CDs in silica matrix. We also demonstrate that the S-CDs can be applied as a color-converting phosphor for typical GaN UV light emitting diodes (LEDs) with significant improvements in stability as well as processability. - Highlights: • Carbon dots can be uniformly embedded in ionic salt crystals via crystallization. • Salt crystals provide oxygen-tight matrices for protecting carbon dots from degradations. • Salt-embedded carbon dots can be applied as a stable color-converting phosphor in LEDs.

  19. Effect of pigment concentration on fastness and color values of thermal and UV curable pigment printing

    Science.gov (United States)

    Baysal, Gulcin; Kalav, Berdan; Karagüzel Kayaoğlu, Burçak

    2017-10-01

    In the current study, it is aimed to determine the effect of pigment concentration on fastness and colour values of thermal and ultraviolet (UV) curable pigment printing on synthetic leather. For this purpose, thermal curable solvent-based and UV curable water-based formulations were prepared with different pigment concentrations (3, 5 and 7%) separately and applied by screen printing technique using a screen printing machine. Samples printed with solvent-based formulations were thermally cured and samples printed with water-based formulations were cured using a UV curing machine equipped with gallium and mercury (Ga/Hg) lamps at room temperature. The crock fastness values of samples printed with solvent-based formulations showed that increase in pigment concentration was not effective on both dry and wet crock fastness values. On the other hand, in samples printed with UV curable water-based formulations, dry crock fastness was improved and evaluated as very good for all pigment concentrations. However, increasing the pigment concentration affected the wet crock fastness values adversely and lower values were observed. As the energy level increased for each irradiation source, the fastness values were improved. In comparison with samples printed with solvent-based formulations, samples printed with UV curable water-based formulations yielded higher K/S values at all pigment concentrations. The results suggested that, higher K/S values can be obtained in samples printed with UV curable water-based formulations at a lower pigment concentration compared to samples printed with solvent-based formulations.

  20. Drop and recovery of thermal conductivity of AlN upon UV irradiation

    International Nuclear Information System (INIS)

    AlShaikhi, A; Srivastava, G P

    2007-01-01

    We have performed calculations of the room-temperature thermal conductivity of oxygen contaminated aluminium nitride (AlN) by employing the Callaway model with a detailed account of three-phonon scattering processes. The role of Al vacancy and O substitution of N has been examined in the form of extended defects (clusters) and point defects. Our work provides support for the theoretical model proposed by Harris et al. [Phys. Rev. B. 47, 5428 (1993)] to explain the experimentally observed drop in the conductivity upon UV irradiation and its recovery upon UV removal and subsequent illumination of the sample with visible light at room temperature. With the reported oxygen concentration in the sample, the scattering of phonons from oxygen-related extended defects is found to be ineffective. Within the picture presented by Harris et al., the point impurity scattering parameter increases by around 17% upon UV irradiation of the sample at room temperature

  1. Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

    Directory of Open Access Journals (Sweden)

    Barthelemy Mathieu

    2014-01-01

    Full Text Available The solar UV (UltraViolet flux, especially the EUV (Extreme UltraViolet and FUV (Far UltraViolet components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope. We also show that the estimation of some particular line parameters (intensity and shape, especially Lyman α, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

  2. Near UV-visible line emission from tungsten highly-charged ions in Large Helical Device

    International Nuclear Information System (INIS)

    Kato, D.; Sakaue, H.A.; Murakami, I.; Goto, M.; Oishi, T.; Morita, S.; Fujii, K.; Nakamura, N.; Koike, F.; Sasaki, Akira; Ding, X.-B.; Dong, C.-Z.

    2015-01-01

    Wavelengths of emission lines from tungsten highly-charged ions have been precisely measured in near UV-visible range (320 - 356 nm and 382 - 402 nm) at Large Helical Device (LHD) by tungsten pellet injection. The tungsten emission lines were assigned based on its line-integrated intensity profiles on a poloidal cross section. The ground-term magnetic-dipole (M1) lines of W 26+,27+ and an M1 line of a metastable excited state of W 28+ , whose wavelengths have been determined by measurements using electron-beam-ion-traps (EBITs), are identified in the LHD spectra. The present results partially compliment wavelength data of tungsten highly-charged ions in the near UV-visible range. (author)

  3. Electron cyclotron emission from thermal plasmas

    International Nuclear Information System (INIS)

    Fidone, I.; Granata, G.

    1978-02-01

    Electron cyclotron radiation from a warm inhomogeneous plasma is investigated. A direct calculation of the emissive power of a plasma slab is performed using Rytov's method and the result is compared with the solution of the transfer equation. It is found that, for arbitrary directions of emission, the two results differ, which reflects the fact that Kirchhoff's law is not generally obeyed

  4. Tricolor emission Ca3Si2O7:Ln (Ln=Ce, Tb, Eu) phosphors for near-UV white light-emitting-diode

    International Nuclear Information System (INIS)

    Mao, Zhi-yong; Zhu, Ying-chun; Gan, Lin; Zeng, Yi; Xu, Fang-fang; Wang, Yang; Tian, Hua; Li, Jian; Wang, Da-jian

    2013-01-01

    Tricolor emission in a same Ca 3 Si 2 O 7 host with independent Ln (Ln=Ce 3+ , Eu 2+ , Tb 3+ ) dopants is demonstrated to construct a near-UV white light emitting diode (LED). The luminescence properties and thermal quenching properties, as well as the applications in near-UV white LED are investigated. These phosphors show typical blue, red, and green, three-basal-color, luminescence in the CIE chromaticity diagram for Ce 3+ , Eu 2+ and Tb 3+ dopants, respectively. Thermal quenching properties show that the luminescence thermal stability strongly depends on the different dopant types; better thermal quenching property of Ce 3+ and Tb 3+ is recorded in comparison with that of Eu 2+ . The white LED prototype fabricated with near-UV chip and as-prepared tricolor phosphors exhibits acceptable CIE chromaticity coordinates (0.32, 0.30) with a CCT of 6000 K and a CRI of 87, indicating the potential application of Ca 3 Si 2 O 7 :Ln phosphors in near-UV white LED. - Highlights: ► Tricolor Ca 3 Si 2 O 7 : Ln phosphors were demonstrated to construct near-UV white LED. ► Eu 2+ doped Ca 3 Si 2 O 7 red-emitting phosphor was confirmed by this work once again. ► Thermal quenching properties for Ca 3 Si 2 O 7 :Ln phosphors were reported for the first time. ► Performances of fabricated white LED indicated the potential application of phosphors.

  5. Effect of hybrid UV-thermal energy stimuli on inactivation of S. epidermidis andB. subtilis bacterial bioaerosols

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Gi Byoung; Jung, Jae Hee; Jeong, Tae Gun; Lee, Byung Uk, E-mail: leebu@konkuk.ac.kr [Aerosol and Bioengineering Laboratory, Department of Mechanical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-Gu, Seoul, 143-701(Korea, Republic of)

    2010-11-01

    Bioaerosols have become an increasingly important issue due to their harmful effects on human health. As the concern over airborne microorganisms grows, so does the need to develop and study efficient methods of controlling them. In this study, we designed a hybrid system involving ultraviolet (UV) irradiation and thermal energy and investigated its effects on bacterial bioaerosols, followed by a comparison with thermal energy alone and UV irradiation alone. The results show that the hybrid effect caused no variation in the shape of the normalized particle size distributions of S. epidermidis and B. subtilis bioaerosols. However, a physical transport loss of bacterial bioaerosols developed as the temperature inside the glass quartz tube increased. When bacterial bioaerosols were simultaneously exposed to UV irradiation and thermal energy for less than 1.05 s, more than 99% of S. epidermidis bioaerosols were inactivated at 120 {sup o}C with exposure to one UV lamp and at 80 {sup o}C with exposure to two UV lamps; and 93.5% and 98.5% of B. subtilis bioaerosols were inactivated at 280 {sup o}C with exposure to one and two UV lamps, respectively. Moreover, the hybrid UV-thermal stimuli significantly reduced the concentration of ozone, which is a secondary UV-induced pollutant. Our results show that to obtain the same inactivation efficiency, the hybrid UV-thermal stimuli were more efficient than thermal energy alone in terms of energy consumption and produced significantly less ozone than UV irradiation alone. The hybrid stimuli also had higher inactivation efficiency than UV alone. Therefore, these results provide valuable information for the development of new methods for controlling bioaerosols.

  6. How Does Abundance Affect the Strength of UV Emission in Elliptical Galaxies?

    Science.gov (United States)

    Sonneborn, George (Technical Monitor); Brown, Thomas

    2005-01-01

    This program used the Far Ultraviolet Spectroscopic Explorer (FUSE) to observe elliptical galaxies with the intention of measuring the chemical abundances in their hot stellar populations. It was designed to complement an earlier FUSE program that observed elliptical galaxies with strong UV emission. The current program originally planned observations of two ellipticals with weak UV emission (M32 and M49). Once FUSE encountered pointing control problems in certain regions of the sky (particularly Virgo, which is very unfortunate for the study of ellipticals in general), M49 was replaced with the bulge of M31, which has a similar UV-to-optical flux ratio as the center of M49. As the closest elliptical galaxy and the one with the weakest UV-to-optical flux ratio, M32 was an obvious choice of target, but M49 was the ideal complementary target, because it has a very low reddening (unlike M32). With the inability of FUSE to point at Virgo, nearly all of the best elliptical galaxies (bright galaxies with low foreground extinction) were also lost, and this severely hampered three FUSE programs of the PI, all focused on the hot stellar populations of ellipticals. M31 was the best replacement for M49, but like M32, it suffers from significant foreground reddening. Strong Galactic ISM lines heavily contaminate the FUSE spectra of M31 and M32. These ISM lines are coincident with the photospheric lines from the stellar populations (whereas M49, with little foreground ISM and significant redshift, would not have suffered from this problem). We have reduced the faint (and thus difficult) data for M31 and M32, producing final co-added spectra representing all of the exposures, but we have not yet finished our analysis, due to the complication of the contaminating ISM. The silver lining here is the set of CHI lines at 1175 Angstroms, which are not significantly contaminated by the ISM. A comparison of the M31 spectrum with other galaxies observed by FEE showed a surprising result

  7. Improvement of thermal stability of UV curable pressure sensitive adhesive by surface modified silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Beili; Ryu, Chong-Min; Kim, Hyung-Il, E-mail: hikim@cnu.ac.kr

    2013-11-01

    Highlights: • Silica nanoparticles were modified to carry the vinyl groups for photo-crosslinking. • Acrylic copolymer was modified to have the vinyl groups for photo-crosslinking. • Strong and extensive interfacial bondings were formed between polymer and silica. • Thermal stability of PSA was improved by forming nanocomposite with modified silica. -- Abstract: Pressure sensitive adhesives (PSAs) with higher thermal stability were successfully prepared by forming composite with the silica nanoparticles modified via reaction with 3-methacryloxypropyltrimethoxysilane. The acrylic copolymer was synthesized as a base resin for PSAs by solution polymerization of 2-EHA, EA, and AA with AIBN as an initiator. The acrylic copolymer was further modified with GMA to have the vinyl groups available for UV curing. The peel strength decreased with the increase of gel content which was dependent on both silica content and UV dose. Thermal stability of the composite PSAs was improved noticeably with increasing silica content and UV dose mainly due to the strong and extensive interfacial bonding between the organic polymer matrix and silica.

  8. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    Science.gov (United States)

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  9. Thermal radio emission from the winds of single stars

    International Nuclear Information System (INIS)

    Abbott, D.C.

    1985-01-01

    Observations of thermal emission at radio wavelengths provides a powerful diagnostic of the rate of mass loss and temperature of the winds of early-type stars. Some winds are also strong sources of nonthermal emission. Case studies of known thermal and nonthermal sources provide empirical criteria for classifying the observed radio radiation. Mass loss rates are derived for 37 OB and Wolf-Rayet stars considered definite or probable thermal wind sources by these criteria. The rate of mass loss is strongly linked to stellar luminosity in OB stars and probably linked to stellar mass in Wolf-Rayet stars, with no measurable correlation with any other stellar property. A few late-type giants and supergiants also have detectable thermal emission, which arises from extended, accelerating, partially-ionized chromospheres. (orig.)

  10. Quenching and blue shift of UV emission intensity of hydrothermally grown ZnO:Mn nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Vinod, R. [Department of Physics, Cochin University of Science and Technology, Kochi 682022, Kerala (India); Junaid Bushiri, M., E-mail: junaidbushiri@gmail.com [Department of Physics, Cochin University of Science and Technology, Kochi 682022, Kerala (India); Achary, Sreekumar Rajappan; Muñoz-Sanjosé, Vicente [Departamento de FisicaAplicada y Electromagnetismo, Universitat de Valencia, c/Dr. Moliner 50, Burjassot, Valencia 46100 (Spain)

    2015-01-15

    Highlights: • Single crystalline ZnO:Mn nanorods. • Reduced optical active defects. • Quenching and blue shift of UV emission. - Abstract: ZnO:Mn alloyed nanorods (Mn nominal concentration – 3–5 wt%) were synthesized by using hydrothermal process at an optimized growth temperature of 200 °C and a growth time of 3 h. The XRD, SEM and Raman, FTIR investigations reveal that ZnO:Mn (Mn – 3–5 wt%) retained hexagonal wurtzite crystal structure with nanorod morphology. The HRTEM and SAED analysis confirm the single crystalline nature of hydrothermally grown ZnO and ZnO:Mn (5 wt%) nanorods. The ZnO:Mn nanorods (Mn – 0–5 wt%) displayed optical band gap in the range 3.23–3.28 eV. The blue shift of UV emission peak (PL) from 393 (ZnO) to 386 nm and quenching of photoluminescence emission in ZnO:Mn is due to the Mn incorporation in ZnO lattice. Relative increase in intensity of Raman band at 660 cm{sup −1} with nominal doping of Mn 3–5 wt% in ZnO indicate that defects are introduced in ZnO:Mn system as a result of doping that leads to the quenching of photoluminescence emission at 393 nm.

  11. Acoustic emission from thermal-gradient cracks in UO2

    International Nuclear Information System (INIS)

    Kennedy, C.R.; Kupperman, D.S.; Wrona, B.J.

    1975-01-01

    A feasibility study has been conducted to evaluate the potential use of acoustic emission to monitor thermal-shock damage in direct electrical heating of UO 2 pellets. In the apparatus used for the present tests, two acoustic-emission sensors were placed on extensions of the upper and lower electrical feedthroughs. Commercially available equipment was used to accumulate acoustic-emission data. The accumulation of events displayed on a cathode-ray-tube screen indicates the total number of acoustic-emission events at a particular location within the pellet stack. These tests have indicated that acoustic emission can be used to monitor thermal-shock damage in UO 2 pellets subjected to direct-electrical heating. 8 references

  12. Electronic structure and thermal decomposition of 5-aminotetrazole studied by UV photoelectron spectroscopy and theoretical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Rui M., E-mail: ruipinto@fct.unl.pt [CFA, Centro de Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Dias, Antonio A.; Costa, Maria L. [CFA, Centro de Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2011-03-18

    Graphical abstract: Gas-phase UV photoelectron spectrum of the thermal decomposition of 5-aminotetrazole (5ATZ), obtained at 245 {sup o}C, and mechanism underlying the thermal dissociation of 2H-5ATZ. Research highlights: {yields} Electronic structure of 5ATZ studied by photoelectron spectroscopy. {yields} Gas-phase 5-ATZ exists mainly as the 2H-tautomer. {yields} Thermal decomposition of 5ATZ gives N{sub 2}, NH{sub 2}CN, HN{sub 3} and HCN, at 245 {sup o}C. {yields} HCN can be originated from a carbene intermediate. - Abstract: The electronic properties and thermal decomposition of 5-aminotetrazole (5ATZ) are investigated using UV photoelectron spectroscopy (UVPES) and theoretical calculations. Simulated spectra of both 1H- and 2H-5ATZ, based on electron propagator methods, are produced in order to study the relative gas-phase tautomer population. The thermal decomposition results are rationalized in terms of intrinsic reaction coordinate (IRC) calculations. 5ATZ yields a HOMO ionization energy of 9.44 {+-} 0.04 eV and the gas-phase 5ATZ assumes mainly the 2H-form. The thermal decomposition of 5ATZ leads to the formation of N{sub 2}, HN{sub 3} and NH{sub 2}CN as the primary products, and HCN from the decomposition of a intermediate CH{sub 3}N{sub 3} compound. The reaction barriers for the formation of HN{sub 3} and N{sub 2} from 2H-5ATZ are predicted to be {approx}228 and {approx}150 kJ/mol, at the G2(MP2) level, respectively. The formation of HCN and HNNH from the thermal decomposition of a CH{sub 3}N{sub 3} carbene intermediate is also investigated.

  13. The injury and cumulative effects on human skin by UV exposure from artificial fluorescence emission.

    Science.gov (United States)

    Tian, Yan; Liu, Wei; Niu, TianHui; Dai, CaiHong; Li, Xiaoxin; Cui, Caijuan; Zhao, Xinyan; E, Yaping; Lu, Hui

    2014-01-01

    The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low-dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low-dose group with a cumulative dose of 50 J cm(-2) which was equivalent to irradiation of the face during indoor work for 1.5 years; and high-dose group with 1000 J cm(-2) cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low-dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP-1, p53 and SIRT1 expression was also increased. Long-term exposure of low-dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention. © 2014 The American Society of Photobiology.

  14. Sparse estimation of model-based diffuse thermal dust emission

    Science.gov (United States)

    Irfan, Melis O.; Bobin, Jérôme

    2018-03-01

    Component separation for the Planck High Frequency Instrument (HFI) data is primarily concerned with the estimation of thermal dust emission, which requires the separation of thermal dust from the cosmic infrared background (CIB). For that purpose, current estimation methods rely on filtering techniques to decouple thermal dust emission from CIB anisotropies, which tend to yield a smooth, low-resolution, estimation of the dust emission. In this paper, we present a new parameter estimation method, premise: Parameter Recovery Exploiting Model Informed Sparse Estimates. This method exploits the sparse nature of thermal dust emission to calculate all-sky maps of thermal dust temperature, spectral index, and optical depth at 353 GHz. premise is evaluated and validated on full-sky simulated data. We find the percentage difference between the premise results and the true values to be 2.8, 5.7, and 7.2 per cent at the 1σ level across the full sky for thermal dust temperature, spectral index, and optical depth at 353 GHz, respectively. A comparison between premise and a GNILC-like method over selected regions of our sky simulation reveals that both methods perform comparably within high signal-to-noise regions. However, outside of the Galactic plane, premise is seen to outperform the GNILC-like method with increasing success as the signal-to-noise ratio worsens.

  15. Thermal stability and practical applications of UV induced index changes in silica glasses

    DEFF Research Database (Denmark)

    Rathje, Jacob

    2000-01-01

    This thesis represents the partial fulfilment of the requirements for the danish ph.d. degree. I have been involved in both basic research of UV induced refractive index changes in silica glasses and in concrete applications. I have performed work on the thermal stability of UV-induced index...... the asymmetry showed good agreement with the obeserved data. The results were used to make a direction sensitive bend sensor of only one fiber. The sensor has further the advantage that it is insensitve to cross sensitivity from temperature, strin, and other external factors. Finally, an investigation of Nragg...... changes in silica glasses where a new continuous isochronal annealing method was introduced. The method was applied to gratings written in D2-loaded fibers and non-loaded fibers. For the non-loaded fibers the obtained results are in good agreement with what has previously been observed. For the D2-loaded...

  16. Apparatus and method for transient thermal infrared emission spectrometry

    Science.gov (United States)

    McClelland, John F.; Jones, Roger W.

    1991-12-24

    A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

  17. Charting thermal emission variability at Pele, Janus Patera and Kanehekili Fluctus with the Galileo NIMS Io Thermal Emission Database (NITED)

    Science.gov (United States)

    Davies, Ashley Gerard; Veeder, Glenn J.; Matson, Dennis L.; Johnson, Torrence V.

    2012-09-01

    Using the NIMS Io Thermal Emission Database (NITED), a collection of over 1000 measurements of radiant flux from Io’s volcanoes (Davies, A.G. et al. [2012]. Geophys. Res. Lett. 39, L01201. doi:10.1029/2011GL049999), we have examined the variability of thermal emission from three of Io’s volcanoes: Pele, Janus Patera and Kanehekili Fluctus. At Pele, the 5-μm thermal emission as derived from 28 night time observations is remarkably steady at 37 ± 10 GW μm-1, re-affirming previous analyses that suggested that Pele an active, rapidly overturning silicate lava lake. Janus Patera also exhibits relatively steady 5-μm thermal emission (≈20 ± 3 GW μm-1) in the four observations where Janus is resolved from nearby Kanehekili Fluctus. Janus Patera might contain a Pele-like lava lake with an effusion rate (QF) of ≈40-70 m3 s-1. It should be a prime target for a future mission to Io in order to obtain data to determine lava eruption temperature. Kanehekili Fluctus has a thermal emission spectrum that is indicative of the emplacement of lava flows with insulated crusts. Effusion rate at Kanehekili Fluctus dropped by an order of magnitude from ≈95 m3 s-1 in mid-1997 to ≈4 m3 s-1 in late 2001.

  18. UV Digital Imaging of Sulfur Dioxide Emissions: Enhancing the Technique With Empirical Corrections

    Science.gov (United States)

    Dalton, M. P.; Bluth, G. J.; Shannon, J. M.; Watson, I. M.

    2006-12-01

    SO2 emission measurements are an important component of monitoring volcanic processes, providing insight into the driving forces behind eruptions. Current spectrometric methods (COSPEC, DOAS) typically measure only a cross-section of the plume, which may not be representative of the actual emission flux, and coupled with the difficulty in determining wind speeds affecting the air mass, often leads to erratic SO2 flux values. In order to address these problems, we have developed a ground-based ultraviolet digital camera for the imaging and measurement of SO2 volcanic plumes. This camera improves on the spectrometric methods of SO2 observation by capturing a large portion of the plume in one measurement- a single image. The UV digital camera can also record multiple images every minute, producing a data set that is more comparable with other monitoring techniques. The UV digital camera has proven capable of imaging volcanic plumes under fairly demanding conditions, and determining SO2 fluxes that have roughly agreed with other SO2 measurement techniques. Initial field tests suggest that the data produced by the UV camera are significantly affected by atmospheric scattering. To better evaluate the errors and limitations associated with this new instrument, field experiments have been conducted to assess the effects that background sky brightness, meteorological conditions, and distance to the target have on the calculated SO2 concentrations and flux measurements. Our results will allow us to more accurately model and correct for changing atmospheric conditions and quantify the error associated with atmospheric background scattering. These corrections will make this remarkable new instrument a more accurate and valuable tool for monitoring volcanic emissions.

  19. Thermal history regulates methylbutenol basal emission rate in Pinus ponderosa.

    Science.gov (United States)

    Gray, Dennis W; Goldstein, Allen H; Lerdau, Manuel T

    2006-07-01

    Methylbutenol (MBO) is a 5-carbon alcohol that is emitted by many pines in western North America, which may have important impacts on the tropospheric chemistry of this region. In this study, we document seasonal changes in basal MBO emission rates and test several models predicting these changes based on thermal history. These models represent extensions of the ISO G93 model that add a correction factor C(basal), allowing MBO basal emission rates to change as a function of thermal history. These models also allow the calculation of a new emission parameter E(standard30), which represents the inherent capacity of a plant to produce MBO, independent of current or past environmental conditions. Most single-component models exhibited large departures in early and late season, and predicted day-to-day changes in basal emission rate with temporal offsets of up to 3 d relative to measured basal emission rates. Adding a second variable describing thermal history at a longer time scale improved early and late season model performance while retaining the day-to-day performance of the parent single-component model. Out of the models tested, the T(amb),T(max7) model exhibited the best combination of day-to-day and seasonal predictions of basal MBO emission rates.

  20. Highly Efficient Organic UV Photodetectors Based on Polyfluorene and Naphthalenediimide Blends: Effect of Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Gorkem Memisoglu

    2012-01-01

    Full Text Available A solution-processed organic ultraviolet photodetector (UV-PD is introduced. The active layer of the UV-PD consists of poly(9,9-dioctyl fluorenyl-2,7–yleneethynylene (PFE and N,N′-bis-n-butyl-1,4,5,8- naphthalenediimide (BNDI with a weight ratio of 3 : 1 in chloroform. The effect of thermal annealing on the device properties was investigated from room temperature to 80∘C. The full device structure of ITO/PEDOT:PSS/PFE:BNDI (3 : 1/Al gave responsivity of 410 mA/W at −4 V under 1 mW/cm2 UV light at 368 nm when 60∘C of annealing temperature was used during its preparation. The devices that were annealed over the crystallization temperature of PFE showed a charge transfer resistance increase and a mobility decrease.

  1. Eu{sup 3+} emission in phosphate glasses with high UV transparency

    Energy Technology Data Exchange (ETDEWEB)

    Silva, G.H. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Anjos, V., E-mail: virgilio@fisica.ufjf.br [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Bell, M.J.V. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Carmo, A.P. [Instituto Federal Fluminense-Campus Cabo Frio, CP 112015, CEP 28909-971 Cabo Frio, RJ (Brazil); Pinheiro, A.S.; Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberlândia, CP 593, CEP 38400-902 Uberlândia, MG (Brazil)

    2014-10-15

    We report a study of the phosphate glass PZABP (P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO) doped with europium (Eu{sup 3+}) in different concentrations. Absorption, photoluminescence and time resolved photoluminescence were used to investigate the influence of increasing Eu{sup 3+} concentrations. The present glass exhibits Eu{sup 3+} absorption bands in the ultraviolet region (about 300 nm) due to the high transparency of the system compared to other phosphate glasses. In this way, it was possible to obtain the Judd–Ofelt parameters from the emission and absorption spectra. Moreover, a strong red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed. It was found that the radiative lifetime and the quantum efficiency of the Eu{sup 3+} level, {sup 5}D{sub 0}, do not suffer a significant change as the concentration of Eu{sup 3+} ions increases. - Highlights: • UV transparent glass matrix is used for Eu{sup 3+} doping. • Judd–Ofelt parameters from the emission and absorption spectra were obtained. • Red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed.

  2. Thermal properties and flame retardancy of an ether-type UV-cured polyurethane coating

    Directory of Open Access Journals (Sweden)

    2010-09-01

    Full Text Available A new UV-reactive monomer piperazine-N,N′-bis(acryloxyethylaryl-phosphoramidate (N-PBAAP containing phosphorus and nitrogen was synthesized and used as flame retardant for an ether-type UV-cured polyurethane acrylate (PUA coating. The thermal properties of the PUA films were investigated by thermogravimetric analysis (TGA in air and nitrogen atmosphere. The TGA results showed that the incorporation of N-PBAAP can obviously enhance the char residue of the PUA coatings. From the TGA and real time Fourier transformed infrared spectroscopy (RT-FTIR results, different degradation behaviors were observed in the PUA coatings with different N-PBAAP content. The combustibility of the PUA coatings was evaluated by microscale combustion calorimeter (MCC. The MCC results revealed that the addition of NPBAAP in the coatings can significantly reduce the peak Heat Release Rate (pHRR, Heat Release Capacity (HRC and the Total Heat Release (THR of the samples. Furthermore, dynamical mechanical thermal analysis (DMA was employed to examine the viscoelastic properties of the PUA films. It was found that the incorporation of N-PBAAP in the formulation can bring in more functional groups to the coatings, which results in an increase of the glass transition temperature (Tg and cross linking density (XLD of the films.

  3. Modification of Thermal Emission via Metallic Photonic Crystals

    International Nuclear Information System (INIS)

    Norris, David J.; Stein, Andreas; George, Steven M.

    2012-01-01

    Photonic crystals are materials that are periodically structured on an optical length scale. It was previously demonstrated that the glow, or thermal emission, of tungsten photonic crystals that have a specific structure - known as the 'woodpile structure' - could be modified to reduce the amount of infrared radiation from the material. This ability has implications for improving the efficiency of thermal emission sources and for thermophotovoltaic devices. The study of this effect had been limited because the fabrication of metallic woodpile structures had previously required a complex fabrication process. In this project we pursued several approaches to simplify the fabrication of metallic photonic crystals that are useful for modification of thermal emission. First, we used the self-assembly of micrometer-scale spheres into colloidal crystals known as synthetic opals. These opals can then be infiltrated with a metal and the spheres removed to obtain a structure, known as an inverse opal, in which a three-dimensional array of bubbles is embedded in a film. Second, we used direct laser writing, in which the focus of an infrared laser is moved through a thin film of photoresist to form lines by multiphoton polymerization. Proper layering of such lines can lead to a scaffold with the woodpile structure, which can be coated with a refractory metal. Third, we explored a completely new approach to modified thermal emission - thin metal foils that contain a simple periodic surface pattern, as shown in Fig. 1. When such a foil is heated, surface plasmons are excited that propagate along the metal interface. If these waves strike the pattern, they can be converted into thermal emission with specific properties.

  4. Emission and thermal performance upgrade through advanced control backfit

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, A.K. [Stone & Webster Engineering Corporation, Boston, MA (United States)

    1994-12-31

    Reducing emission and improving thermal performance of currently operating power plants is a high priority. A majority of these power plants are over 20 years old with old control systems. Upgrading the existing control systems with the latest technology has many benefits, the most cost beneficial are the reduction of emission and improving thermal performance. The payback period is usually less than two years. Virginia Power is installing Stone & Webster`s NO{sub x} Emissions Advisor and Advanced Steam Temperature Control systems on Possum Point Units 3 and 4 to achieve near term NO{sub x} reductions while maintaining high thermal performance. Testing has demonstrated NO{sub x} reductions of greater than 20 percent through the application of NO{sub x} Emissions Advisor on these units. The Advanced Steam Temperature Control system which has been operational at Virginia Power`s Mt. Storm Unit 1 has demonstrated a signification improvement in unit thermal performance and controllability. These control systems are being combined at Units 3 and 4 to reduce NO{sub x} emissions and achieve improved unit thermal performance and control response with the existing combustion hardware. Installation has been initiated and is expected to be completed by the spring of 1995. Possum Point Power Station Units 3 and 4 are pulverized coal, tangentially fired boilers producing 107 and 232 MW and have a distributed control system and a PC based performance monitoring system. The installation of the advanced control and automation system will utilize existing control equipment requiring the addition of several PCs and PLC.

  5. [Effects of silicon supply on rice growth and methane emission from paddy soil under elevated UV-B radiation].

    Science.gov (United States)

    Meng, Yan; Lou, Yun-sheng; Wu, Lei; Cui, He-yang; Wang, Wei-qing

    2015-01-01

    A pot experiment was conducted to investigate the effects of silicon supply on rice growth and methane (CH4) emission in paddy field under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B (ambient, A) and elevated UV-B radiation (elevated by 20%, E) ; with four silicon supply levels, i.e., Si0 (control, without silicon), Si2 (as sodium silicate, 100 kg SiO2 . hm-2), Si2 (as sodium silicate, 200 kg SiO2 hm-2) and Si3 (as slag fertilizer, 200 kg SiO2 . hm-2). The results indicated that, silicon supply obviously alleviated the depressive effect of elevated UV-B radiation on rice growth, and increased the tiller numbers, chlorophyll content, and shoot and root dry masses. Silicon supply promoted rice growth, which increased with the silicon supply level (sodium silicate). Slag fertilizer was better than*sodium silicate in promoting rice growth. CH4 flux and accumulated CH4emission were obviously increased by elevated UV-B radiation, but significantly decreased by silicon application. CH4 emission was reduced with increasing the silicon supply level. Under the same silicon supply level, slag fertilizer was better than sodium silicate in inhibiting CH4 flux and accumulated CH4 emission. This research suggested that fertilizing slag in rice production was helpful not only in utilizing industrial wastes, but also in significantly mitigating CH4 emissions in rice paddy under elevated UV-B radiation.

  6. Investigation of room temperature UV emission of ZnO films with different defect densities induced by laser irradiation.

    Science.gov (United States)

    Zhao, Yan; Jiang, Yijian

    2010-08-01

    We studied the room temperature UV emission of ZnO films with different defect densities which is fabricated by KrF laser irradiation process. It is shown room temperature UV photoluminescence of ZnO film is composed of contribution from free-exciton (FX) recombination and its longitudinal-optical phonon replica (FX-LO) (1LO, 2LO). With increase of the defect density, the FX emission decreased and FX-LO emission increased dramatically; and the relative strengths of FX to FX-LO emission intensities determine the peak position and intensity of UV emission. What is more, laser irradiation with moderate energy density could induce the crystalline ZnO film with very flat and smooth surface. This investigation indicates that KrF laser irradiation could effectively modulate the exciton emission and surface morphology, which is important for the application of high performance of UV emitting optoelectronic devices. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Effect of Ag doping on the properties of ZnO thin films for UV stimulated emission

    Science.gov (United States)

    Razeen, Ahmed S.; Gadallah, A.-S.; El-Nahass, M. M.

    2018-06-01

    Ag doped ZnO thin films have been prepared using sol-gel spin coating method, with different doping concentrations. Structural and morphological properties of the films have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Thin films have been optically pumped and stimulated emission has been observed with strong peaks in the UV region. The UV stimulated emission is found to be due to exciton-exciton scattering, and Ag doping promoted this process by increasing the excitons concentrations in the ZnO lattice. Output-input intensity relation and peak emission, FWHM, and quantum efficiency relations with pump intensity have been reported. The threshold for which stimulated emission started has been evaluated to be about 18 MW/cm2 with quantum efficiency of about 58.7%. Mechanisms explaining the role of Ag in enhancement of stimulated emission from ZnO thin films have been proposed.

  8. Thermal conductivity and emissivity measurements of uranium carbides

    International Nuclear Information System (INIS)

    Corradetti, S.; Manzolaro, M.; Andrighetto, A.; Zanonato, P.; Tusseau-Nenez, S.

    2015-01-01

    Highlights: • Thermal conductivity and emissivity measurements of uranium carbides were performed. • The tested materials are candidates as targets for radioactive ion beam production. • The results are correlated with the materials composition and microstructure. - Abstract: Thermal conductivity and emissivity measurements on different types of uranium carbide are presented, in the context of the ActiLab Work Package in ENSAR, a project within the 7th Framework Program of the European Commission. Two specific techniques were used to carry out the measurements, both taking place in a laboratory dedicated to the research and development of materials for the SPES (Selective Production of Exotic Species) target. In the case of thermal conductivity, estimation of the dependence of this property on temperature was obtained using the inverse parameter estimation method, taking as a reference temperature and emissivity measurements. Emissivity at different temperatures was obtained for several types of uranium carbide using a dual frequency infrared pyrometer. Differences between the analyzed materials are discussed according to their compositional and microstructural properties. The obtainment of this type of information can help to carefully design materials to be capable of working under extreme conditions in next-generation ISOL (Isotope Separation On-Line) facilities for the generation of radioactive ion beams.

  9. Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

    Science.gov (United States)

    Bruhweiler, F.; Verner, E.

    2008-03-01

    We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm -3) ] = 11.0, log [ΦH/(cm -2 s-1) ] = 20.5, and ξ/(1 km s-1) = 20, using Cloudy and an 830 level model atom for Fe II with energies up to 14.06 eV, gives a better fit to the UV Fe II emission than models with fewer levels. Our analysis indicates (1) the observed UV Fe II emission must be corrected for an underlying Fe II pseudocontinuum; (2) Fe II emission peaks can be misidentified as that of other ions in active galactic nuclei (AGNs) with narrow-lined BLRs possibly affecting deduced physical parameters; (3) the shape of 4200-4700 Å Fe II emission in I Zw 1 and other AGNs is a relative indicator of narrow-line region (NLR) and BLR Fe II emission; (4) predicted ratios of Lyα, C III], and Fe II emission relative to Mg II λ2800 agree with extinction corrected observed I Zw 1 fluxes, except for C IV λ1549 (5) the sensitivity of Fe II emission strength to microturbulence ξ casts doubt on existing relative Fe/Mg abundances derived from Fe II (UV)/Mg II flux ratios. Our calculated Fe II emission spectra, suitable for BLRs in AGNs, are available at http://iacs.cua.edu/people/verner/FeII. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 05-26555.

  10. Acute exposure to UV-B sensitizes cucumber, tomato, and Arabidopsis plants to photooxidative stress by inhibiting thermal energy dissipation and antioxidant defense

    International Nuclear Information System (INIS)

    Moon, Yu-Ran; Lee, Min-Hee; Chung, Byung-Yeoup; Kim, Jin-Hong; Tovuu, Altanzaya; Lee, Choon-Hwan; Park, Youn-Il

    2011-01-01

    The purpose of this study was to characterize a change in Non-photochemical quenching (NPQ) upon exposure to ultraviolet-B (UV-B), the xanthophyll cycle-dependent and -independent NPQs were compared in Cucumis sativus, Lycopersicum esculentum, and Arabidopsis thaliana leaves. The xanthophyll cycle-dependent NPQ was dramatically but reversibly suppressed by UV-B radiation. This suppression was correlated more strongly with a marked decrease in photosynthetic electron transport rather than changes in xanthophyll cycle enzymes such as violaxanthin de-epoxidase and zeaxanthin epoxidase. Accordingly, the UV-B-induced suppression of NPQ cannot be attributed to changes in expressions of violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). However, suppression of the xanthophyll cycle-dependent NPQ could only account for the 77 K fluorescence emission spectra of thylakoid membranes and the increased level of 1 O 2 production, but not for the decreased levels of hydroxyl radical O 2 - production and H 2 O 2 scavenging. These results suggest that a gradual reduction of H 2 O 2 scavenging activity as well as a transient and reversible suppression of thermal energy dissipation may contribute differentially to increased photooxidative damages in cucumber, tomato, and Arabidopsis plants after acute exposure to UV-B radiation. (author)

  11. Control of Several Emissions during Olive Pomace Thermal Degradation

    Directory of Open Access Journals (Sweden)

    Teresa Miranda

    2014-10-01

    Full Text Available Biomass plays an important role as an energy source, being an interesting alternative to fossil fuels due to its environment-friendly and sustainable characteristics. However, due to the exposure of customers to emissions during biomass heating, evolved pollutants should be taken into account and controlled. Changing raw materials or mixing them with another less pollutant biomass could be a suitable step to reduce pollution. This work studied the thermal behaviour of olive pomace, pyrenean oak and their blends under combustion using thermogravimetric analysis. It was possible to monitor the emissions released during the process by coupling mass spectrometry analysis. The experiments were carried out under non-isothermal conditions at the temperature range 25–750 °C and a heating rate of 20 °C·min−1. The following species were analysed: aromatic compounds (benzene and toluene, sulphur emissions (sulphur dioxide, 1,4-dioxin, hydrochloric acid, carbon dioxide and nitrogen oxides. The results indicated that pollutants were mainly evolved in two different stages, which are related to the thermal degradation steps. Thus, depending on the pollutant and raw material composition, different emission profiles were observed. Furthermore, intensity of the emission profiles was related, in some cases, to the composition of the precursor.

  12. Dynamics, OH distributions and UV emission of a gliding arc at various flow-rates investigated by optical measurements

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Sun, Zhiwei; Li, Zhongshan

    2014-01-01

    -state OH were investigated using planar laser-induced fluorescence. The results show that the shape, height, intensity and thickness of ground-state OH distribution vary significantly with air flow rates. Finally, UV emission of the gliding arc is measured using optical emission spectroscopy......We demonstrate a plasma discharge which is generated between two diverging electrodes and extended into a gliding arc in non-equilibrium condition by an air flow at atmospheric pressure. Effects of the air flow rates on the dynamics, ground-state OH distributions and spectral characterization of UV...

  13. Flame retardancy and thermal degradation of cotton textiles based on UV-curable flame retardant coatings

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Weiyi [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China); Jie, Ganxin [State Key Laboratory of Environmental Adaptability for Industrial Products, China National Electric Apparatus Research Institute, Guangzhou 510300 (China); Song, Lei; Hu, Shuang; Lv, Xiaoqi; Wang, Xin [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China)

    2011-01-20

    The flame retardant coatings were prepared through UV-curable technique using tri(acryloyloxyethyl) phosphate (TAEP) and triglycidyl isocyanurate acrylate (TGICA). Results from FTIR-ATR spectroscopy and scanning electron microscopy (SEM) showed that flame retardant coatings were successfully coated onto the surface of cotton fabrics. The flame retardancy of the treated fabrics was studied by Micro-scale Combustion Calorimeter (MCC) and limited oxygen index (LOI). The cottons coated flame retardant coatings had the lower peak heat release rate (PHRR), heat release capacity (HRC), total heat of combustion (THC) and higher LOI value compared with untreated cotton. The results from TGA test showed that the flame retardant coatings lowered the decomposition temperature of treated fabric. The thermal decomposition of cottons was monitored by real time FTIR analysis and thermogravimetric analysis/infrared spectrometry (TGA-IR). The enhanced flame retardant action might be caused by thermal decomposition of TAEP structure, producing acidic intermediates, which could react with fabrics to alter its thermal decomposition process.

  14. Variations of the Hβ-emission line during a large flare on UV Ceti

    International Nuclear Information System (INIS)

    Moffett, T.J.; Evans, D.S.; Ferland, G.

    1977-01-01

    Simultaneous high-speed photometry and photoelectric scanner observations of the Hβ-line were obtained for five flare events, one a major flare, on UV Ceti on 1975 January 6. The relative increase in the intensity of the Hβ-line during the large flare was much greater than the relative continuum rise as measured both by the scanner and by broad-band photometric observations. In Hβ the flare lasted nearly 30 times as long as in the continuum. Peak intensity in the Hβ-line occurred later than the continuum maximum. The possibility of using emission line observations to detect flare activity on early spectral-type stars (dK - dG) is discussed. Some speculations on the mechanism of flare production are indulged. (author)

  15. Magnetic dichroism in UV photoemission at off-normal emission: Study of the valence bands

    International Nuclear Information System (INIS)

    Venus, D.; Kuch, W.; Lin, M.; Schneider, C.M.; Ebert, H.; Kirschner, J.

    1997-01-01

    Magnetic dichroism of angle-resolved UV photoemission from fcc Co/Cu(001) thin films has been measured using linearly p-polarized light, and a coplanar geometry where the light and photoelectron wave vectors are antiparallel, and both are perpendicular to the in-plane sample magnetization. This geometry emphasizes information about state dispersion due to the crystalline symmetry. An orderly dispersion of the features in the magnetic dichroism over a wide range of off-normal angles of electron emission is related in detail to the bulk band structure of fcc Co. The measurements confirm the practical utility of magnetic dichroism experiments as a relatively simple complement to spin-resolved photoemission. copyright 1997 The American Physical Society

  16. Investigation of HNCO isomer formation in ice mantles by UV and thermal processing: An experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Escobar, A.; Giuliano, B. M.; Caro, G. M. Muñoz; Cernicharo, J. [Centro de Astrobiología, INTA-CSIC, Carretera de Ajalvir, km 4, Torrejón de Ardoz, E-28850 Madrid (Spain); Marcelino, N., E-mail: bgiuliano@cab.inta-csic.es [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2014-06-10

    Current gas-phase models do not account for the abundances of HNCO isomers detected in various environments, suggesting their formation in icy grain mantles. We attempted to study a formation channel of HNCO and its possible isomers by vacuum-UV photoprocessing of interstellar ice analogs containing H{sub 2}O, NH{sub 3}, CO, HCN, CH{sub 3}OH, CH{sub 4}, and N{sub 2} followed by warm-up under astrophysically relevant conditions. Only the H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ice mixtures led to the production of HNCO species. The possible isomerization of HNCO to its higher energy tautomers following irradiation or due to ice warm-up has been scrutinized. The photochemistry and thermal chemistry of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices were simulated using the Interstellar Astrochemistry Chamber, a state-of-the-art ultra-high-vacuum setup. The ice was monitored in situ by Fourier transform mid-infrared spectroscopy in transmittance. A quadrupole mass spectrometer detected the desorption of the molecules in the gas phase. UV photoprocessing of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices lead to the formation of OCN{sup –} as a main product in the solid state and a minor amount of HNCO. The second isomer HOCN has been tentatively identified. Despite its low efficiency, the formation of HNCO and the HOCN isomers by UV photoprocessing of realistic simulated ice mantles might explain the observed abundances of these species in photodissociation regions, hot cores, and dark clouds.

  17. High power uv metal vapor ion lasers pumped by thermal energy charge exchange

    International Nuclear Information System (INIS)

    Kan, T.

    1975-01-01

    The requirement for efficient and scalable laser sources for laser isotope separation (LIS) has recently been brought into sharp focus. The lack of suitable coherent sources is particularly severe in the uv, a spectral region of interest for more efficient and advanced isotope separation schemes. This report explores the general class of metal vapor ion lasers pumped by thermal energy charge exchange (TECX) as possible scalable coherent sources for LIS with the following potential characteristics: (1) availability of discrete wavelengths spanning the wavelength region between 2000 A less than lambda less than 8000 A, (2) pulsed or cw operation in the multi-kilowatt average power levels, (3) overall device efficiencies approaching one percent, and (4) the engineering of practical laser devices using relatively benign electron beam technology. (U.S.)

  18. Thermally excited proton spin-flip laser emission in tokamaks

    International Nuclear Information System (INIS)

    Arunasalam, V.; Greene, G.J.

    1993-07-01

    Based on statistical thermodynamic fluctuation arguments, it is shown here for the first time that thermally excited spin-flip laser emission from the fusion product protons can occur in large tokamak devices that are entering the reactor regime of operation. Existing experimental data from TFTR supports this conjecture, in the sense that these measurements are in complete agreement with the predictions of the quasilinear theory of the spin-flip laser

  19. Standoff laser-induced thermal emission of explosives

    Science.gov (United States)

    Galán-Freyle, Nataly Y.; Pacheco-Londoño, Leonardo C.; Figueroa-Navedo, Amanda; Hernandez-Rivera, Samuel P.

    2013-05-01

    A laser mediated methodology for remote thermal excitation of analytes followed by standoff IR detection is proposed. The goal of this study was to determine the feasibility of using laser induced thermal emission (LITE) from vibrationally excited explosives residues deposited on surfaces to detect explosives remotely. Telescope based FT-IR spectral measurements were carried out to examine substrates containing trace amounts of threat compounds used in explosive devices. The highly energetic materials (HEM) used were PETN, TATP, RDX, TNT, DNT and ammonium nitrate with concentrations from 5 to 200 μg/cm2. Target substrates of various thicknesses were remotely heated using a high power CO2 laser, and their mid-infrared (MIR) thermally stimulated emission spectra were recorded. The telescope was configured from reflective optical elements in order to minimize emission losses in the MIR frequencies and to provide optimum overall performance. Spectral replicas were acquired at a distance of 4 m with an FT-IR interferometer at 4 cm- 1 resolution and 10 scans. Laser power was varied from 4-36 W at radiation exposure times of 10, 20, 30 and 60 s. CO2 laser powers were adjusted to improve the detection and identification of the HEM samples. The advantages of increasing the thermal emission were easily observed in the results. Signal intensities were proportional to the thickness of the coated surface (a function of the surface concentration), as well as the laser power and laser exposure time. For samples of RDX and PETN, varying the power and time of induction of the laser, the calculated low limit of detections were 2 and 1 μg/cm2, respectively.

  20. X-ray/UV variability and the origin of soft X-ray excess emission from II Zw 177

    Science.gov (United States)

    Pal, Main

    We study a detailed broad-band X-ray/UV emission from the narrow line Seyfert 1 galaxy II Zw 177 based on two XMM-Newton and single Swift/XRT observations. Both XMM-Newton observations show the soft X-ray excess emission below 2 keV when the best-fit 2 - 10 keV power law is extrapolated down to 0.3 keV. We find the blurred reflection from an ionized accretion disc and Comptonized disc emission both describe the observed soft excess well. We find a remarkable trend of decreasing UV flux with increasing soft X-ray excess and power law emission. We suggest that this could be due to that the external edge of corona hide a fraction of accretion disk. Co-Author: Prof. Gulab C. Dewangan (IUCAA), Prof. Ranjeev Misra (IUCAA), Pramod Kumar (Nanded university)

  1. Environmental emissions control programs at Lambton TGS [Thermal Generating Station

    International Nuclear Information System (INIS)

    Kalvins, A.K.

    1992-01-01

    Ontario Hydro's air emissions control programs at Lambton thermal generating station, both committed and planned, are reviewed, and their potential impacts on emissions, effluents and wastes are discussed. Control technologies examined include flue gas conditioning, wet limestone scrubbing, combustion process modifications, urea injection, and selective catalytic reduction. The implementation of these technologies has the potential to create new solid and liquid waste disposal problems, the full extent of which is often not realized at the process selection stage. For example, selective noncatalytic reduction using urea injection can lead to increased CO emissions, escape of unreacted ammonia from the stack at levels of 5-50 ppM, increase in N 2 O emissions, contamination of fly ash, gypsum and waste water with ammonia, and an increase in CO 2 emissions of less than 0.4% due to increased power consumption. Optimum performance of the air emissions control systems, with minimum negative impact on the environment, requires consideration of the impact of these systems on all waste streams. 11 refs., 3 figs., 1 tab

  2. Acoustic Emission Analysis of Damage Progression in Thermal Barrier Coatings Under Thermal Cyclic Conditions

    Science.gov (United States)

    Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

    2015-01-01

    Damage evolution of electron beam-physical vapor deposited (EBVD-PVD) ZrO2-7 wt.% Y2O3 thermal barrier coatings (TBCs) under thermal cyclic conditions was monitored using an acoustic emission (AE) technique. The coatings were heated using a laser heat flux technique that yields a high reproducibility in thermal loading. Along with AE, real-time thermal conductivity measurements were also taken using infrared thermography. Tests were performed on samples with induced stress concentrations, as well as calcium-magnesium-alumino-silicate (CMAS) exposure, for comparison of damage mechanisms and AE response to the baseline (as-produced) coating. Analysis of acoustic waveforms was used to investigate damage development by comparing when events occurred, AE event frequency, energy content and location. The test results have shown that AE accumulation correlates well with thermal conductivity changes and that AE waveform analysis could be a valuable tool for monitoring coating degradation and provide insight on specific damage mechanisms.

  3. Construction of TSL lector equipment with spectral resolution for the determination of thermally stimulated luminescence (TSL) properties of NaCl: Tl+ induced by UV-visible radiation

    International Nuclear Information System (INIS)

    Alvarez Romero, J.T.

    1993-01-01

    A revision of physical models of thermally stimulated luminescence (TSL) in crystals induced by both ionizing and non-ionizing radiation is presented. Particular emphasis is given to the connection of TSL with other thermally stimulated processes and physico-chemical phenomena because basic information on physical mechanics for TSL can be obtained through them. Glow curves of TSL induced by UV-visible radiation in NaCl: Tl + were measured. Additionally, the following spectrums were obtained for the same samples: optical absorption, excitation, fluorescent emission, and TSL emission. An optical absorption peak was correlated with the Thallium ion concentration. With respect to the TSL emission spectrums, some peaks associated to Thallium dimmers were at 298 and at 480 nm; others which were attributed to NaCl intrinsic properties were at 365, 430, 450 and 525 nm. Also TSL glow curves were studied as a function of the Thallium ion concentration (0.8 ppm to 14.8 ppm). They were de convoluted so as to calculate the activation energy, the frequency factor and the kinetic order for each separate TSL peak. Anomalous values were observed for some frequency factors. A method and TSL lector equipment to obtain TSL emission spectra were developed. (Author)

  4. Thermal emission characteristics of a graded index semitransparent medium

    International Nuclear Information System (INIS)

    Huang Yong; Dong Sujun; Yang Min; Wang Jun

    2008-01-01

    This paper develops a numerical model for thermal radiative transfer in a two-dimensional semitransparent graded index medium. A piecewise continuous refractive index model, the linear refractive index bar model, is presented. This model is established based on three hypotheses, and has a higher precision than the bar model used previously. This paper also studies the thermal emission from a two-dimensional graded index medium, which is scattering or non-scattering. We find that it can present an obvious pattern of directional distribution at times. The refractive index distribution and absorption coefficient are the two main influential factors. This finding differs from the common belief that thermal sources, such as the incandescent filament of a light bulb, emit a quasi-isotropic light. The finding also suggests that there maybe other important applications of artificial GRIN materials

  5. Novel Organic Phototransistor-Based Nonvolatile Memory Integrated with UV-Sensing/Green-Emissive Aggregation Enhanced Emission (AEE)-Active Aromatic Polyamide Electret Layer.

    Science.gov (United States)

    Cheng, Shun-Wen; Han, Ting; Huang, Teng-Yung; Chang Chien, Yu-Hsin; Liu, Cheng-Liang; Tang, Ben Zhong; Liou, Guey-Sheng

    2018-05-30

    A novel aggregation enhanced emission (AEE)-active polyamide TPA-CN-TPE with a high photoluminesence characteristic was successfully synthesized by the direct polymerization of 4-cyanotriphenyl diamine (TPA-CN) and tetraphenylethene (TPE)-containing dicarboxylic acid. The obtained luminescent polyamide plays a significant role as the polymer electret layer in organic field-effect transistors (OFETs)-type memory. The strong green emission of TPA-CN-TPE under ultraviolet (UV) irradiation can be directly absorbed by the pentacene channel, displaying a light-induced programming and voltage-driven erasing organic phototransistor-based nonvolatile memory. Memory window can be effectively manipulated between the programming and erasing states by applying UV light illumination and electrical field, respectively. The photoinduced memory behavior can be maintained for over 10 4 s between these two states with an on/off ratio of 10 4 , and the memory switching can be steadily operated for many cycles. With high photoresponsivity ( R) and photosensitivity ( S), this organic phototransistor integrated with AEE-active polyamide electret layer could serve as an excellent candidate for UV photodetectors in optical applications. For comparison, an AEE-inactive aromatic polyimide TPA-PIS electret with much weaker solid-state emission was also applied in the same OFETs device architecture, but this device did not show any UV-sensitive and UV-induced memory characteristics, which further confirmed the significance of the light-emitting capability of the electret layer.

  6. UV induced photoluminescence and thermally stimulated luminescence of ThO{sub 2}:Tb{sup 3+} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Godbole, S.V.; Nagpal, J.S.; Page, A.G. E-mail: agpage@magnum.barc.ernet.in

    2000-08-15

    Thorium oxide doped with trivalent terbium ions offers itself as a novel phosphor with its photo- and thermally-stimulated luminescence (PL and TSL) characteristics showing a marked change on sustained exposure to 254 and 365 nm ultraviolet (UV) radiation. The reduction in luminescence intensity of Tb{sup 3+} ions, on irradiation with 254 nm photons and subsequent restoration on exposure to 365 nm, has been correlated with the complimentary behaviour in UV-induced TSL. These changes are, in turn, ascribed to inter-configurational (f-d) transitions and e-h formation and recombination processes. UV radiation induced TSL output increases linearly with incident UV radiant energy at a constant radiation flux; however, for a fixed exposure, TSL output increases with increase in radiant flux.

  7. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    Science.gov (United States)

    La Forgia, Fiorangela; Bodewits, Dennis; A'Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony

    2017-11-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact. Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H2O directly produces excited OH*(A 2Σ+) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  8. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    Energy Technology Data Exchange (ETDEWEB)

    La Forgia, Fiorangela [Department of Physics and Astronomy, University of Padova, Vicolo dellOsservatorio 3, I-35122 Padova (Italy); Bodewits, Dennis; A’Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony, E-mail: fiorangela.laforgia@unipd.it [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)

    2017-11-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact . Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H{sub 2}O directly produces excited OH*( A {sup 2}Σ{sup +}) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  9. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    International Nuclear Information System (INIS)

    La Forgia, Fiorangela; Bodewits, Dennis; A’Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony

    2017-01-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact . Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H 2 O directly produces excited OH*( A 2 Σ + ) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  10. SG1120-1202: Mass-quenching as Tracked by UV Emission in the Group Environment at z=0.37

    Science.gov (United States)

    Monroe, Jonathan T.; Tran, Kim-Vy H.; Gonzalez, Anthony H.

    2017-02-01

    We use the Hubble Space Telescope to obtain WFC3/F390W imaging of the supergroup SG1120-1202 at z=0.37, mapping the UV emission of 138 spectroscopically confirmed members. We measure total (F390W-F814W) colors and visually classify the UV morphology of individual galaxies as “clumpy” or “smooth.” Approximately 30% of the members have pockets of UV emission (clumpy) and we identify for the first time in the group environment galaxies with UV morphologies similar to the “jellyfish” galaxies observed in massive clusters. We stack the clumpy UV members and measure a shallow internal color gradient, which indicates that unobscured star formation is occurring throughout these galaxies. We also stack the four galaxy groups and measure a strong trend of decreasing UV emission with decreasing projected group distance ({R}{proj}). We find that the strong correlation between decreasing UV emission and increasing stellar mass can fully account for the observed trend in (F390W-F814W)-{R}{proj}, I.e., mass-quenching is the dominant mechanism for extinguishing UV emission in group galaxies. Our extensive multi-wavelength analysis of SG1120-1202 indicates that stellar mass is the primary predictor of UV emission, but that the increasing fraction of massive (red/smooth) galaxies at {R}{proj} ≲ 2 R 200 and existence of jellyfish candidates is due to the group environment.

  11. Thermal and non-thermal emission from NGC 1275(3C84)

    International Nuclear Information System (INIS)

    Gear, W.K.; Robson, E.I.; Gee, G.; Nolt, I.G.

    1985-01-01

    Millimetre, submillimetre, far- and near-infrared observations of the unusual galaxy NGC 1275 are presented. After subtraction of the near-infrared stellar contamination of the surrounding galaxy the non-stellar emission at these wavelengths is investigated. It is concluded that the millimetre-wave and near-infrared emission is synchrotron radiation from a very compact component. It is shown that the emission at wavelengths from 10-400 μm is dominated by thermal emission with a spectrum very similar to NGC 1068. It is shown that the material for star formation in NGC 1275 is almost certainly being provided by accretion in a cooling flow from the Perseus intracluster gas with only approx. 2 per cent of the accreting mass forming OBA stars. (author)

  12. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    Optical absorber coatings have been developed from carbon-based paints, metal blacks, or glassy carbon. However, such materials are not truly black and have poor absorption characteristics at longer wavelengths. The blackness of such coatings is important to increase the accuracy of calibration targets used in radiometric imaging spectrometers since blackbody cavities are prohibitively large in size. Such coatings are also useful potentially for thermal detectors, where a broadband absorber is desired. Au-black has been a commonly used broadband optical absorber, but it is very fragile and can easily be damaged by heat and mechanical vibration. An optically efficient, thermally rugged absorber could also be beneficial for thermal solar cell applications for energy harnessing, particularly in the 350-2,500 nm spectral window. It has been demonstrated that arrays of vertically oriented carbon nanotubes (CNTs), specifically multi-walled-carbon- nanotubes (MWCNTs), are an exceptional optical absorber over a broad range of wavelengths well into the infrared (IR). The reflectance of such arrays is 100x lower compared to conventional black materials, such as Au black in the spectral window of 350-2,500 nm. Total hemispherical measurements revealed a reflectance of approximately equal to 1.7% at lambda approximately equal to 1 micrometer, and at longer wavelengths into the infrared (IR), the specular reflectance was approximately equal to 2.4% at lambda approximately equal to 7 micrometers. The previously synthesized CNTs for optical absorber applications were formed using water-assisted thermal chemical vapor deposition (CVD), which yields CNT lengths in excess of 100's of microns. Vertical alignment, deemed to be a critical feature in enabling the high optical absorption from CNT arrays, occurs primarily via the crowding effect with thermal CVD synthesized CNTs, which is generally not effective in aligning CNTs with lengths less than 10 m. Here it has been shown that the

  13. Photoacoustic emission from Au nanoparticles arrayed on thermal insulation layer.

    Science.gov (United States)

    Namura, Kyoko; Suzuki, Motofumi; Nakajima, Kaoru; Kimura, Kenji

    2013-04-08

    Efficient photoacoustic emission from Au nanoparticles on a porous SiO(2) layer was investigated experimentally and theoretically. The Au nanoparticle arrays/porous SiO(2)/SiO(2)/Ag mirror sandwiches, namely, local plasmon resonators, were prepared by dynamic oblique deposition (DOD). Photoacoustic measurements were performed on the local plasmon resonators, whose optical absorption was varied from 0.03 (3%) to 0.95 by varying the thickness of the dielectric SiO(2) layer. The sample with high absorption (0.95) emitted a sound that was eight times stronger than that emitted by graphite (0.94) and three times stronger than that emitted by the sample without the porous SiO(2) layer (0.93). The contribution of the porous SiO(2) layer to the efficient photoacoustic emission was analyzed by means of a numerical method based on a one-dimensional heat transfer model. The result suggested that the low thermal conductivity of the underlying porous layer reduces the amount of heat escaping from the substrate and contributes to the efficient photoacoustic emission from Au nanoparticle arrays. Because both the thermal conductivity and the spatial distribution of the heat generation can be controlled by DOD, the local plasmon resonators produced by DOD are suitable for the spatio-temporal modulation of the local temperature.

  14. From photoluminescence to thermal emission: Thermally-enhanced PL (TEPL) for efficient PV (Conference Presentation)

    Science.gov (United States)

    Manor, Assaf; Kruger, Nimrod; Martin, Leopoldo L.; Rotschild, Carmel

    2016-09-01

    The Shockley-Queisser efficiency limit of 40% for single-junction photovoltaic (PV) cells is mainly caused by the heat dissipation accompanying the process of electro-chemical potential generation. Concepts such as solar thermo-photovoltaics (STPV) aim to harvest this heat loss by the use of a primary absorber which acts as a mediator between the sun and the PV, spectrally shaping the light impinging on the cell. However, this approach is challenging to realize due to the high operating temperatures of above 2000K required in order to generate high thermal emission fluxes. After over thirty years of STPV research, the record conversion efficiency for STPV device stands at 3.2% for 1285K operating temperature. In contrast, we recently demonstrated how thermally-enhanced photoluminescence (TEPL) is an optical heat-pump, in which photoluminescence is thermally blue-shifted upon heating while the number of emitted photons is conserved. This process generates energetic photon-rates which are comparable to thermal emission in significantly reduced temperatures, opening the way for a TEPL based energy converter. In such a device, a photoluminescent low bandgap absorber replaces the STPV thermal absorber. The thermalization heat induces a temperature rise and a blue-shifted emission, which is efficiently harvested by a higher bandgap PV. We show that such an approach can yield ideal efficiencies of 70% at 1140K, and realistic efficiencies of almost 50% at moderate concentration levels. As an experimental proof-of-concept, we demonstrate 1.4% efficient TEPL energy conversion of an Nd3+ system coupled to a GaAs cell, at 600K.

  15. Thermal emission from interstellar dust in and near the Pleiades

    International Nuclear Information System (INIS)

    White, R.E.

    1989-01-01

    IRAS survey coadds for a 8.7 deg x 4.3 deg field near the Pleiades provide evidence for dynamical interaction between the cluster and the surrounding interstellar medium. The far-infrared images show large region of faint emission with bright rims east of the cluster, suggestive of a wake. Images of the far-infrared color temperature and 100 micron optical depth reveal temperature maxima and optical depth minima near the bright cluster stars, as well as a strong optical depth peak at the core of the adjacent CO cloud. Models for thermal dust emission near the stars indicate that most of the apparent optical depth minima near stars are illusory, but also provide indirect evidence for small interaction between the stars and the encroaching dust cloud

  16. Thermal emission from interstellar dust in and near the Pleiades

    Science.gov (United States)

    White, Richard E.

    1989-01-01

    IRAS survey coadds for a 8.7 deg x 4.3 deg field near the Pleiades provide evidence for dynamical interaction between the cluster and the surrounding interstellar medium. The far-infrared images show large region of faint emission with bright rims east of the cluster, suggestive of a wake. Images of the far-infrared color temperature and 100 micron optical depth reveal temperature maxima and optical depth minima near the bright cluster stars, as well as a strong optical depth peak at the core of the adjacent CO cloud. Models for thermal dust emission near the stars indicate that most of the apparent optical depth minima near stars are illusory, but also provide indirect evidence for small interaction between the stars and the encroaching dust cloud.

  17. Highly crystalline carbon dots from fresh tomato: UV emission and quantum confinement

    Science.gov (United States)

    Liu, Weijian; Li, Chun; Sun, Xiaobo; Pan, Wei; Yu, Guifeng; Wang, Jinping

    2017-12-01

    In this article, fresh tomatoes are explored as a low-cost source to prepare high-performance carbon dots by using microwave-assisted pyrolysis. Given that amino groups might act as nucleophiles for cleaving covalent bridging ester or ether in the crosslinked macromolecules in the biomass bulk, ethylenediamine (EDA) and urea with amino groups were applied as nucleophiles to modulate the chemical composites of the carbon nanoparticles in order to tune their fluorescence emission and enhance their quantum yields. Very interestingly, the carbon dots synthesized in the presence of urea had a highly crystalline nature, a low-degree amorphous surface and were smaller than 5 nm. Moreover, the doped N contributed to the formation of a cyclic form of core that resulted in a strong electron-withdrawing ability within the conjugated C plane. Therefore, this type of carbon dot exhibited marked quantum confinement, with the maximum fluorescence peak located in the UV region. Carbon nanoparticles greater than 20 nm in size, prepared using pristine fresh tomato and in the presence of EDA, emitted surface state controlled fluorescence. Additionally, carbon nanoparticles synthesized using fresh tomato pulp in the presence of EDA and urea were explored for bioimaging of plant pathogenic fungi and the detection of vanillin.

  18. Strongly coupled Coulomb systems with positive dust grains: thermal and UV-induced plasmas

    International Nuclear Information System (INIS)

    Samarian, A.A.

    2000-01-01

    Full text: A plasma containing macroscopic dust particles or grains (often referred to as a dusty or colloidal or complex plasma) has the feature that grains may be charged by electron or ion flux or by photo- or thermoelectron emission. Electron emission from a grain surface produces a positive charge; capture of electrons produces the reverse effect making the dust grains negatively charged. Most dusty plasma research is concerned with the ordered dust structures (so-called 'plasma crystal') in glow discharges. The dust grains in these experiments were found to carry a negative charge due to the higher mobility of electrons as compared to ions in the discharge plasma. In recent years, in parallel with the study of the properties of plasma crystals under discharge conditions, attempts to obtain a structure from positively charged dust grains have been made, and structure formation processes for various charging mechanisms, particularly thermoelectron emission and photoemission, have been investigated. In this paper we review the essential features of strongly coupled plasmas with positive dust grains. An ordered structure of CeO 2 grains has been experimentally observed in a combustion products jet. The grains were charged positively and suspended in the plasma flow. Their charge is about 10 3 a and the calculated value of a Coulomb coupling parameter Γ is >10, corresponding to a plasma liquid. The ordered structures of Al 2 O 3 dust grains in propellant combustion products plasma have been observed for the first time. These structures were found in the sheath boundary of condensation region. The obtained data let us estimate the value of parameter Γ =3-40, corresponding to the plasma liquid state. The possibility is studied of the formation of ordered dust grain structures in thermal plasma. The range of the required values of the coupling parameter Γ is calculated using the results of diagnostic measurements carried out in thermal plasma with grains of

  19. Inkjet 3D printing of UV and thermal cure silicone elastomers for dielectric elastomer actuators

    Science.gov (United States)

    McCoul, David; Rosset, Samuel; Schlatter, Samuel; Shea, Herbert

    2017-12-01

    Dielectric elastomer actuators (DEAs) are an attractive form of electromechanical transducer, possessing high energy densities, an efficient design, mechanical compliance, high speed, and noiseless operation. They have been incorporated into a wide variety of devices, such as microfluidic systems, cell bioreactors, tunable optics, haptic displays, and actuators for soft robotics. Fabrication of DEA devices is complex, and the majority are inefficiently made by hand. 3D printing offers an automated and flexible manufacturing alternative that can fabricate complex, multi-material, integrated devices consistently and in high resolution. We present a novel additive manufacturing approach to DEA devices in which five commercially available, thermal and UV-cure DEA silicone rubber materials have been 3D printed with a drop-on-demand, piezoelectric inkjet system. Using this process, 3D structures and high-quality silicone dielectric elastomer membranes as thin as 2 μm have been printed that exhibit mechanical and actuation performance at least as good as conventionally blade-cast membranes. Printed silicone membranes exhibited maximum tensile strains of up to 727%, and DEAs with printed silicone dielectrics were actuated up to 6.1% area strain at a breakdown strength of 84 V μm-1 and also up to 130 V μm-1 at 2.4% strain. This approach holds great potential to manufacture reliable, high-performance DEA devices with high throughput.

  20. Modelling of non-thermal electron cyclotron emission during ECRH

    International Nuclear Information System (INIS)

    Tribaldos, V.; Krivenski, V.

    1990-01-01

    The existence of suprathermal electrons during Electron Cyclotron Resonance Heating experiments in tokamaks is today a well established fact. At low densities the creation of large non-thermal electron tails affects the temperature profile measurements obtained by 2 nd harmonic, X-mode, low-field side, electron cyclotron emission. At higher densities suprathermal electrons can be detected by high-field side emission. In electron cyclotron current drive experiments a high energy suprathermal tail, asymmetric in v, is observed. Non-Maxwellian electron distribution functions are also typically observed during lower-hybrid current drive experiments. Fast electrons have been observed during ionic heating by neutral beams as well. Two distinct approaches are currently used in the interpretation of the experimental results: simple analytical models which reproduce some of the expected non-Maxwellian characteristics of the electron distribution function are employed to get a qualitative picture of the phenomena; sophisticated numerical Fokker-Planck calculations give the electron distribution function from which the emission spectra are computed. No algorithm is known to solve the inverse problem, i.e. to compute the electron distribution function from the emitted spectra. The proposed methods all relay on the basic assumption that the electron distribution function has a given functional dependence on a limited number of free parameters, which are then 'measured' by best fitting the experimental results. Here we discuss the legitimacy of this procedure. (author) 7 refs., 5 figs

  1. Evaluation of accelerated UV and thermal testing for benzene formation in beverages containing benzoate and ascorbic acid.

    Science.gov (United States)

    Nyman, Patricia J; Wamer, Wayne G; Begley, Timothy H; Diachenko, Gregory W; Perfetti, Gracia A

    2010-04-01

    Under certain conditions, benzene can form in beverages containing benzoic and ascorbic acids. The American Beverage Assn. (ABA) has published guidelines to help manufacturers mitigate benzene formation in beverages. These guidelines recommend accelerated testing conditions to test product formulations, because exposure to ultraviolet (UV) light and elevated temperature over the shelf life of the beverage may result in benzene formation in products containing benzoic and ascorbic acids. In this study, the effects of UVA exposure on benzene formation were determined. Benzene formation was examined for samples contained in UV stabilized and non-UV stabilized packaging. Additionally, the usefulness of accelerated thermal testing to simulate end of shelf-life benzene formation was evaluated for samples containing either benzoic or ascorbic acid, or both. The 24 h studies showed that under intense UVA light benzene levels increased by as much as 53% in model solutions stored in non-UV stabilized bottles, whereas the use of UV stabilized polyethylene terephthalate bottles reduced benzene formation by about 13% relative to the non-UV stabilized bottles. Similar trends were observed for the 7 d study. Retail beverages and positive and negative controls were used to study the accelerated thermal testing conditions. The amount of benzene found in the positive controls and cranberry juice suggests that testing at 40 degrees C for 14 d may more reliably simulate end of shelf-life benzene formation in beverages. Except for cranberry juice, retail beverages were not found to contain detectable amounts of benzene (<0.05 ng/g) at the end of their shelf lives.

  2. Evolution of the near-UV emission spectrum associated with the reduction process in microwave iron making.

    Science.gov (United States)

    Matsubara, Akihiro; Takayama, Sadatsugu; Okajima, Shigeki; Sato, Motoyasu

    2008-01-01

    The structure of the emission spectrum in the near-UV range (240 nm-310 nm) changes drastically from the continuous spectrum to a discrete line spectrum with increasing sample temperature during the carbothermic reduction of magnetite in a 2.45 GHz microwave multimode furnace. The continuous spectrum can be assigned as a cathodoluminescence of magnetite. The dynamic evolution of the spectrum from continuous to discrete represents the progress of the reduction from magnetite to iron.

  3. White organic light-emitting diodes utilized by near UV-deep blue emitter and exciplex emission.

    Science.gov (United States)

    Park, Young Wook; Kim, Young Min; Choi, Jin Hwan; Park, Tae Hyun; Choi, Hyun Ju; Yu, Hong Jung; Cho, Min Ju; Choi, Dong Hoon; Kim, Sung Hyun; Ju, Byeong Kwon

    2011-02-01

    Numerous investigations have been made into the development of wide color gamut displays for deep-blue OLEDs, including the RGB sub pixels, and white OLEDs (WOLEDs). One of the well known deep-blue emissive dopants, tris(phenyl-methyl-benzimidazolyl)iridium(III) [Ir(pmb)3], successfully introduced its fascinating color coordinate of Commission Internationale de l'Eclairage (CIE) 1931 (0.17, 0.06), however there have been no reports utilizing its accomplishments as WOLEDs. In this report, using only one phosphorescent dopant, the near UV-deep blue emissive Ir(pmb)3, the WOLEDs having the CIE 1931 coordinate of (0.33, 0.38) at 100 cd/m2 with a color rendering index of 85 are demonstrated. The white emission of the fabricated OLEDs are oriented from the near UV-deep blue emission of Ir(pmb)3 and the successfully controlled exciplex emission, between the Ir(pmb)3-host, and the Ir(pmb)3-interfaced material.

  4. Spectral characterization of surface emissivities in the thermal infrared

    Science.gov (United States)

    Niclòs, Raquel; Mira, Maria; Valor, Enric; Caselles, Diego; García-Santos, Vicente; Caselles, Vicente; Sánchez, Juan M.

    2015-04-01

    Thermal infrared (TIR) remote sensing trends to hyperspectral sensors on board satellites in the last decades, e.g., the current EOS-MODIS and EOS-ASTER and future missions like HyspIRI, ECOSTRESS, THIRSTY and MISTIGRI. This study aims to characterize spectrally the emissive properties of several surfaces, mostly soils. A spectrometer ranging from 2 to 16 μm, D&P Model 102, has been used to measure samples with singular spectral features, e.g. a sandy soil rich in gypsum sampled in White Sands (New Mexico, USA), salt samples, powdered quartz, and powdered calcite. These samples were chosen for their role in the assessment of thermal emissivity of soils, e.g., the calcite and quartz contents are key variables for modeling TIR emissivities of bare soils, along with soil moisture and organic matter. Additionally, the existence of large areas in the world with abundance of these materials, some of them used for calibration/validation activities of satellite sensors and products, makes the chosen samples interesting. White Sands is the world's largest gypsum dune field encompassing 400 km^2; the salt samples characterize the Salar of Uyuni (Bolivia), the largest salt flat in the world (up to 10,000 km^2), as well as the Jordanian and Israeli salt evaporation ponds at the south end of the Dead Sea, or the evaporation lagoons in Aigües-Mortes (France); and quartz is omnipresent in most of the arid regions of the world such as the Algodones Dunes or Kelso Dunes (California, USA), with areas around 700 km2 and 120 km^2, respectively. Measurements of target leaving radiance, hemispherical radiance reflected by a diffuse reflectance panel, and the radiance from a black body at different temperatures were taken to obtain thermal spectra with the D&P spectrometer. The good consistency observed between our measurements and laboratory spectra of similar samples (ASTER and MODIS spectral libraries) indicated the validity of the measurement protocol. Further, our study showed the

  5. Emission of Polychlorinated Naphthalenes during Thermal Related Processes

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Du, Bing; Liu, Wenbin; Zhang, Bing; Xiao, Ke

    2010-05-01

    Due to the structural similarity of polychlorinated naphthalenes (PCNs) to those of dioxins, PCNs exhibit toxicological properties similar to dioxins (Olivero-Verbel et al., 2004). Based on their high toxicity, persistence, bioaccumulation, and long-distance transmission, PCNs were also selected as a candidate POP for the UN-ECE (United Nations Economic Commission for Europe) POP protocol (Lerche et al., 2002). In addition, some studies suggested that PCNs contributed a greater proportion of the dioxin-like activity than polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) contributed in some locations (Kannan et al., 1998). However, the identification and quantitation for PCN sources are very scarce compared with PCDD/Fs. Understanding the emission levels and developing the emission inventory of PCNs is important for regulatory and source reduction purposes. In this study, several potential sources were preliminarily investigated for PCN release. Coking process (CP), iron ore sintering (IOS), and electric arc furnace steel making units (AF) were selected due to their huge activity level of industrial production in China. Municipal solid waste incineration (MSWI) and medical waste incineration (MWI) were also investigated because of the possible high concentration of PCNs in stack gas. Two plants were investigated for each thermal related process, except for MWI with one incinerator was investigated. The stack gas samples were collected by automatic isokinetic sampling system (Isostack Basic, TCR TECORA, Milan Italy). Isotope dilution high resolution gas chromatography coupled with high resolution mass spectrometry (HRGC/HRMS) technique was used for the identification and quantitation of PCN congeners. The concentrations of PCNs from the selected thermal processes were determined in this study. The average concentrations of total PCNs were 26 ng Nm-3 for CP, 65 ng Nm-3 for IOS, 720 ng Nm-3 for AF, 443 ng Nm-3 for MSWI, and

  6. Thermalization in 2D critical quench and UV/IR mixing

    Science.gov (United States)

    Mandal, Gautam; Paranjape, Shruti; Sorokhaibam, Nilakash

    2018-01-01

    We consider quantum quenches in models of free scalars and fermions with a generic time-dependent mass m( t) that goes from m 0 to zero. We prove that, as anticipated in MSS [1], the post-quench dynamics can be described in terms of a state of the generalized Calabrese-Cardy form | ψ〉 = exp[- κ 2 H - ∑ n >2 ∞ κ n W n ]|Bd〉. The W n ( n = 2, 3, . . ., W 2 = H) here represent the conserved W ∞ charges and |Bd〉 represents a conformal boundary state. Our result holds irrespective of whether the pre-quench state is a ground state or a squeezed state, and is proved without recourse to perturbation expansion in the κ n 's as in MSS. We compute exact time-dependent correlators for some specific quench protocols m( t). The correlators explicitly show thermalization to a generalized Gibbs ensemble (GGE), with inverse temperature β = 4 κ 2, and chemical potentials μ n = 4 κ n . In case the pre-quench state is a ground state, it is possible to retrieve the exact quench protocol m( t) from the final GGE, by an application of inverse scattering techniques. Another notable result, which we interpret as a UV/IR mixing, is that the long distance and long time (IR) behaviour of some correlators depends crucially on all κ n 's, although they are highly irrelevant couplings in the usual RG parlance. This indicates subtleties in RG arguments when applied to non-equilibrium dynamics.

  7. Development of novel cycloaliphatic siloxanes for thermal and UV-curable applications

    Science.gov (United States)

    Chakraborty, Ruby

    Siloxanes have been extensively used as additives to modulate surface properties such as surface tension, hydrophobicity/hydrophobicity, and adhesion, etc. Although, polydimethyl -siloxane and polydiphenylsiloxane are the most commonly used siloxanes, the properties are at extremes in terms of glass transition temperature and flexibility. It is proposed that the ability to control the properties in between the these extremes can be provided by cycloaliphatic substitutions at the siloxane backbone. It is expected that this substitution might work due to the intermediate backbone rigidity. In order to achieve the above objectives, a synthetic route was developed to prepare cycloaliphatic (cyclopentane and cyclohexane) silane monomers followed by subsequent polymerization and functionalizations to obtain glycidyl epoxy, aliphatic amine and methacrylate telechelic siloxanes. The siloxanes were either thermally or UV-cured depending on end functionalizations. Chemical characterization of monomers, oligomers and polymers were performed using 1H, 13C, 29Si-NMR, FT-IR and GPC. The curing kinetics of photo-induced reactions were investigated through photo-differential scanning calorimetry (PDSC). The oxygen permeability, mechanical, coatings, and release properties of siloxanes were studied as a function of the backbone substitutions. The mechanical, coatings and released properties of cycloaliphatic siloxanes improved with respect to polydimethylsiloxanes. The thermal analysis of the cured films were carried out using differential scanning calorimetry (DSC). Viscoelastic properties of the cured siloxanes due to the variation of substitution at the siloxane backbone were measured using dynamic mechanical thermal analysis (DMTA). The cycloaliphatic substituted siloxanes showed an increased glass transition temperature and permeability but reduced crosslink density, conversion, and rate of curing with respect to polydimethylsiloxanes. Hybrids of siloxanes were prepared with

  8. Prospects for Detecting Thermal Emission from Terrestrial Exoplanets with JWST

    Science.gov (United States)

    Kreidberg, Laura

    2018-01-01

    A plethora of nearby, terrestrial exoplanets has been discovered recently by ground-based surveys. Excitingly, some of these are in the habitable zones of their host stars, and may be hospitable for life. However, all the planets orbit small, cool stars and have considerably different irradiation environments from the Earth, making them vulnerable to atmospheric escape, erosion and collapse. Atmosphere characterization is therefore critical to assessing the planets' habitability. I will discuss possible JWST thermal emission measurements to determine the atmospheric properties of nearby terrestrial planets. I will focus on prospects for detecting physically motivated atmospheres for planets orbiting LHS 1140, GJ 1132, and TRAPPIST-1. I will also discuss the potential for using phase curve observations to determine whether an atmosphere has survived on the non-transiting planet Proxima b.

  9. THE DETECTION RATE OF EARLY UV EMISSION FROM SUPERNOVAE: A DEDICATED GALEX/PTF SURVEY AND CALIBRATED THEORETICAL ESTIMATES

    Energy Technology Data Exchange (ETDEWEB)

    Ganot, Noam; Gal-Yam, Avishay; Ofek, Eran O.; Sagiv, Ilan; Waxman, Eli; Lapid, Ofer [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Kulkarni, Shrinivas R.; Kasliwal, Mansi M. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Ben-Ami, Sagi [Smithsonian Astrophysical Observatory, Harvard-Smithsonian Ctr. for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chelouche, Doron; Rafter, Stephen [Physics Department, Faculty of Natural Sciences, University of Haifa, 31905 Haifa (Israel); Behar, Ehud; Laor, Ari [Physics Department, Technion Israel Institute of Technology, 32000 Haifa (Israel); Poznanski, Dovi; Nakar, Ehud; Maoz, Dan [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Trakhtenbrot, Benny [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27 Zurich 8093 (Switzerland); Neill, James D.; Barlow, Thomas A.; Martin, Christofer D., E-mail: noam.ganot@gmail.com [California Institute of Technology, 1200 East California Boulevard, MC 278-17, Pasadena, CA 91125 (United States); Collaboration: ULTRASAT Science Team; WTTH consortium; GALEX Science Team; Palomar Transient Factory; and others

    2016-03-20

    The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early UV observations of core-collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early ultraviolet (UV) emission from SNe. Six SNe II and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX near-UV (NUV) data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that our observations are in good agreement with calculated rates assuming that red supergiants (RSGs) explode with fiducial radii of 500 R{sub ⊙}, explosion energies of 10{sup 51} erg, and ejecta masses of 10 M{sub ⊙}. Exploding blue supergiants and Wolf–Rayet stars are poorly constrained. We describe how such observations can be used to derive the progenitor radius, surface composition, and explosion energy per unit mass of such SN events, and we demonstrate why UV observations are critical for such measurements. We use the fiducial RSG parameters to estimate the detection rate of SNe during the shock-cooling phase (<1 day after explosion) for several ground-based surveys (PTF, ZTF, and LSST). We show that the proposed wide-field UV explorer ULTRASAT mission is expected to find >85 SNe per year (∼0.5 SN per deg{sup 2}), independent of host galaxy extinction, down to an NUV detection limit of 21.5 mag AB. Our pilot GALEX/PTF project thus convincingly demonstrates that a dedicated, systematic SN survey at the NUV band is a compelling method to study how massive stars end their life.

  10. MODIS on-orbit thermal emissive bands lifetime performance

    Science.gov (United States)

    Madhavan, Sriharsha; Wu, Aisheng; Chen, Na; Xiong, Xiaoxiong

    2016-05-01

    MODerate resolution Imaging Spectroradiometer (MODIS), a leading heritage sensor in the fleet of Earth Observing System for the National Aeronautics and Space Administration (NASA) is in space orbit on two spacecrafts. They are the Terra (T) and Aqua (A) platforms. Both instruments have successfully continued to operate beyond the 6 year design life time, with the T-MODIS currently functional beyond 15 years and the A-MODIS operating beyond 13 years respectively. The MODIS sensor characteristics include a spectral coverage from 0.41 μm - 14.4 μm, of which wavelengths ranging from 3.7 μm - 14. 4 μm cover the thermal infrared region also referred to as the Thermal Emissive Bands (TEBs). The TEBs is calibrated using a v-grooved BlackBody (BB) whose temperature measurements are traceable to the National Institute of Standards and Technology temperature scales. The TEBs calibration based on the onboard BB is extremely important for its high radiometric fidelity. In this paper, we provide a complete characterization of the lifetime instrument performance of both MODIS instruments in terms of the sensor gain, the Noise Equivalent difference Temperature, key instrument telemetry such as the BB lifetime trends, the instrument temperature trends, the Cold Focal Plane telemetry and finally, the total assessed calibration uncertainty of the TEBs.

  11. Measures of star formation rates from infrared (Herschel) and UV (GALEX) emissions of galaxies in the HerMES fields

    Science.gov (United States)

    Buat, V.; Giovannoli, E.; Burgarella, D.; Altieri, B.; Amblard, A.; Arumugam, V.; Aussel, H.; Babbedge, T.; Blain, A.; Bock, J.; Boselli, A.; Castro-Rodríguez, N.; Cava, A.; Chanial, P.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dwek, E.; Eales, S.; Elbaz, D.; Fox, M.; Franceschini, A.; Gear, W.; Glenn, J.; Griffin, M.; Halpern, M.; Hatziminaoglou, E.; Heinis, S.; Ibar, E.; Isaak, K.; Ivison, R. J.; Lagache, G.; Levenson, L.; Lonsdale, C. J.; Lu, N.; Madden, S.; Maffei, B.; Magdis, G.; Mainetti, G.; Marchetti, L.; Morrison, G. E.; Nguyen, H. T.; O'Halloran, B.; Oliver, S. J.; Omont, A.; Owen, F. N.; Page, M. J.; Pannella, M.; Panuzzo, P.; Papageorgiou, A.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rigopoulou, D.; Rizzo, D.; Roseboom, I. G.; Rowan-Robinson, M.; Sánchez Portal, M.; Schulz, B.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Strazzullo, V.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vaccari, M.; Valiante, E.; Valtchanov, I.; Vigroux, L.; Wang, L.; Ward, R.; Wright, G.; Xu, C. K.; Zemcov, M.

    2010-11-01

    The reliability of infrared (IR) and ultraviolet (UV) emissions to measure star formation rates (SFRs) in galaxies is investigated for a large sample of galaxies observed with the Spectral and Photometric Imaging Receiver (SPIRE) and the Photodetector Array Camera and Spectrometer (PACS) instruments on Herschel as part of the Herschel Multi-Tiered Extragalactic Survey (HerMES) project. We build flux-limited 250-μm samples of sources at redshift z 500 μm. Dust attenuation is discussed on the basis of commonly used diagnostics: the LIR/LUV ratio and the slope, β, of the UV continuum. A mean dust attenuation AUV of mag is measured in the samples. LIR/LUV is found to correlate with LIR. Galaxies with and 0.5 recipe commonly applied to local starbursts is found to overestimate the dust attenuation correction in our galaxy sample by a factor of ~2-3. The SFRs deduced from LIR are found to account for about 90 per cent of the total SFR; this percentage drops to 71 per cent for galaxies with (or ). For these faint objects, one needs to combine UV and IR emissions to obtain an accurate measure of the SFR.

  12. A thermal after-effect of UV irradiation of muscle glycogen phosphorylase b.

    Directory of Open Access Journals (Sweden)

    Valeriya V Mikhaylova

    Full Text Available Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems based on aggregation of UV-irradiated protein are of special interest because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated glycogen phosphorylase b (UV-Phb from rabbit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-Phb molecule, which contains concealed damage.

  13. A microfabricated, low dark current a-Se detector for measurement of microplasma optical emission in the UV for possible use on-site

    Science.gov (United States)

    Abbaszadeh, Shiva; Karim, Karim S.; Karanassios, Vassili

    2013-05-01

    Traditionally, samples are collected on-site (i.e., in the field) and are shipped to a lab for chemical analysis. An alternative is offered by using portable chemical analysis instruments that can be used on-site (i.e., in the field). Many analytical measurements by optical emission spectrometry require use of light-sources and of spectral lines that are in the Ultra-Violet (UV, ~200 nm - 400 nm wavelength) region of the spectrum. For such measurements, a portable, battery-operated, fiber-optic spectrometer equipped with an un-cooled, linear, solid-state detector may be used. To take full advantage of the advanced measurement capabilities offered by state-of-the-art solid-state detectors, cooling of the detector is required. But cooling and other thermal management hamper portability and use on-site because they add size and weight and they increase electrical power requirements. To address these considerations, an alternative was implemented, as described here. Specifically, a microfabricated solid-state detector for measurement of UV photons will be described. Unlike solid-state detectors developed on crystalline Silicon, this miniaturized and low-cost detector utilizes amorphous Selenium (a-Se) as its photosensitive material. Due to its low dark current, this detector does not require cooling, thus it is better suited for portable use and for chemical measurements on-site. In this paper, a microplasma will be used as a light-source of UV photons for the a-Se detector. For example, spectra acquired using a microplasma as a light-source will be compared with those obtained with a portable, fiber-optic spectrometer equipped with a Si-based 2080-element detector. And, analytical performance obtained by introducing ng-amounts of analytes into the microplasma will be described.

  14. UV Enhanced Oxygen Response Resistance Ratio of ZnO Prepared by Thermally Oxidized Zn on Sapphire Substrate

    Directory of Open Access Journals (Sweden)

    Cheng-Chang Yu

    2013-01-01

    Full Text Available ZnO thin film was fabricated by thermally oxidized Zn at 600°C for 1 h. A surface containing nanostructured dumbbell and lines was observed by scanning electron microscope (SEM. The ZnO resistor device was formed after the following Ti/Au metallization. The device resistance was characterized at different oxygen pressure environment in the dark and under ultraviolet (UV light illumination coming from the mercury lamp with a short pass filter. The resistance increases with the increase of oxygen pressure. The resistance decreases and response increases with the increase of light intensity. Models considering the barrier height variation caused by the adsorbed oxygen related species were used to explain these results. The UV light illumination technology shows an effective method to enhance the detection response for this ZnO resistor oxygen sensor.

  15. Multi-Color QWIP FPAs for Hyperspectral Thermal Emission Instruments

    Science.gov (United States)

    Soibel, Alexander; Luong, Ed; Mumolo, Jason M.; Liu, John; Rafol, Sir B.; Keo, Sam A.; Johnson, William; Willson, Dan; Hill, Cory J.; Ting, David Z.-Y.; hide

    2012-01-01

    Infrared focal plane arrays (FPAs) covering broad mid- and long-IR spectral ranges are the central parts of the spectroscopic and imaging instruments in several Earth and planetary science missions. To be implemented in the space instrument these FPAs need to be large-format, uniform, reproducible, low-cost, low 1/f noise, and radiation hard. Quantum Well Infrared Photodetectors (QWIPs), which possess all needed characteristics, have a great potential for implementation in the space instruments. However a standard QWIP has only a relatively narrow spectral coverage. A multi-color QWIP, which is compromised of two or more detector stacks, can to be used to cover the broad spectral range of interest. We will discuss our recent work on development of multi-color QWIP for Hyperspectral Thermal Emission Spectrometer instruments. We developed QWIP compromising of two stacks centered at 9 and 10.5 ?m, and featuring 9 grating regions optimized to maximize the responsivity in the individual subbands across the 7.5-12 ?m spectral range. The demonstrated 1024x1024 QWIP FPA exhibited excellent performance with operability exceeding 99% and noise equivalent differential temperature of less than 15 mK across the entire 7.5-12 ?m spectral range.

  16. Isoprenoids emission in Stipa tenacissima L.: Photosynthetic control and the effect of UV light

    Czech Academy of Sciences Publication Activity Database

    Guidolotti, G.; Rey, A.; Medori, M.; Calfapietra, Carlo

    2016-01-01

    Roč. 208, B (2016), s. 336-344 ISSN 0269-7491 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LD13031 Institutional support: RVO:67179843 Keywords : Isoprene * Monoterpene * Alfa grass * UV radiation * Semiarid ecosystems Subject RIV: EH - Ecology, Behaviour Impact factor: 5.099, year: 2016

  17. Dynamics, OH distributions and UV emission of a gliding arc at various flow-rates investigated by optical measurements

    International Nuclear Information System (INIS)

    Zhu, Jiajian; Sun, Zhiwei; Li, Zhongshan; Ehn, Andreas; Aldén, Marcus; Salewski, Mirko; Leipold, Frank; Kusano, Yukihiro

    2014-01-01

    We demonstrate a plasma discharge which is generated between two diverging electrodes and extended into a gliding arc in non-equilibrium condition by an air flow at atmospheric pressure. Effects of the air flow rates on the dynamics, ground-state OH distributions and spectral characterization of UV emission of the gliding arc were investigated by optical methods. High-speed photography was utilized to reveal flow-rate dependent dynamics such as ignitions, propagation, short-cutting events, extinctions and conversions of the discharge from glowtype to spark-type. Short-cutting events and ignitions occur more frequently at higher flow rates. The anchor points of the gliding arc are mostly steady at the top of the electrodes at lower flow rates whereas at higher flow rates they glide up along the electrodes most of the time. The afterglow of fully developed gliding arcs is observed to decay over hundreds of microseconds after being electronically short-cut by a newly ignited arc. The extinction time decreases with the increase of the flow rate. The frequency of the conversion of a discharge from glow-type to spark-type increases with the flow rate. Additionally, spatial distributions of ground-state OH were investigated using planar laser-induced fluorescence. The results show that the shape, height, intensity and thickness of ground-state OH distribution vary significantly with air flow rates. Finally, UV emission of the gliding arc is measured using optical emission spectroscopy and it is found that the emission intensity of NO γ (A-X), OH (A-X) and N 2 (C-B) increase with the flow rates showing more characteristics of spark-type arcs. The observed phenomena indicate the significance of the interaction between local turbulence and the gliding arc. (paper)

  18. Dynamics, OH distributions and UV emission of a gliding arc at various flow-rates investigated by optical measurements

    Science.gov (United States)

    Zhu, Jiajian; Sun, Zhiwei; Li, Zhongshan; Ehn, Andreas; Aldén, Marcus; Salewski, Mirko; Leipold, Frank; Kusano, Yukihiro

    2014-07-01

    We demonstrate a plasma discharge which is generated between two diverging electrodes and extended into a gliding arc in non-equilibrium condition by an air flow at atmospheric pressure. Effects of the air flow rates on the dynamics, ground-state OH distributions and spectral characterization of UV emission of the gliding arc were investigated by optical methods. High-speed photography was utilized to reveal flow-rate dependent dynamics such as ignitions, propagation, short-cutting events, extinctions and conversions of the discharge from glowtype to spark-type. Short-cutting events and ignitions occur more frequently at higher flow rates. The anchor points of the gliding arc are mostly steady at the top of the electrodes at lower flow rates whereas at higher flow rates they glide up along the electrodes most of the time. The afterglow of fully developed gliding arcs is observed to decay over hundreds of microseconds after being electronically short-cut by a newly ignited arc. The extinction time decreases with the increase of the flow rate. The frequency of the conversion of a discharge from glow-type to spark-type increases with the flow rate. Additionally, spatial distributions of ground-state OH were investigated using planar laser-induced fluorescence. The results show that the shape, height, intensity and thickness of ground-state OH distribution vary significantly with air flow rates. Finally, UV emission of the gliding arc is measured using optical emission spectroscopy and it is found that the emission intensity of NO γ (A-X), OH (A-X) and N2 (C-B) increase with the flow rates showing more characteristics of spark-type arcs. The observed phenomena indicate the significance of the interaction between local turbulence and the gliding arc.

  19. Mechanical and thermal properties of UV curable polyurethane acrylate composite coatings

    International Nuclear Information System (INIS)

    Mohd Sofian Alias; Nik Ghazali Nik Salleh; Mohd Hamzah Harun; Mohd Yusof Hamzah; Rosley Che Ismail

    2012-01-01

    UV curable coating formulation comprises urethane acrylate resin and nano silica as filter were synthesized to develop UV curable inorganic hybrid composite (PUA). The surface of the nano silica was chemically modified to improve its chemical interaction within the urethane acrylate matrix. The modification had been undertaken by applying vinyltrymetoxysilane (VTMOS) that acted as a coupling agent to produce organophilic silica shell (SIMA). The shell is linked to the silica via reaction with the surface silanol group of the silica. The disappearance of methoxy groups in VTMOS was demonstrated by FTIR spectrum. The percentage of silica particles in UV curable hybrid formulation were varied on 5 %, 10 %, 15 %, 20 % and 25 wt % respectively. In this work, the formulation was applied on medium density fiber board (MDF) substrate and subsequent has been irradiated under UV light. Then, the coated MDF were characterized by several testing equipment (TGA, DSC, scratch tester, instron, SEM). From the result, we found that the addition of silica nanoparticles exhibit significant improvement in coating film properties as compared to film without silica nanoparticle includes significant improvement in its modulus and scratch resistance. This make them as promising coating candidate for MDF product. On the other hand, we also found that an increase of silica particle up to 25 wt %, the viscosity has increased rapidly indicates that it is not suitable for acrylate coating formulation due to disappearance of desired effect known as thixotropy. (Author)

  20. Thermal and optical bleaching of radiation effects in silver activated metaphosphate glass - its use in U.V. dosimetry

    International Nuclear Information System (INIS)

    Nagpal, J.S.; Ramanathan, G.; Gangadharan, P.

    1976-01-01

    While investigating the use of silver activated metaphosphate glass in radiation dosimetry, using its properties of radiophotoluminescence (RPL) in the range 20 mR to 10 3 R and of optical absorbance changes at higher exposures, a difference in the behaviour of the centers responsible for the two phenomenon was observed when the glass was exposed to 253.7 nm u.v. Ultraviolet exposure was observed to bleach the radiophotoluminescence in an irradiated glass whereas it was observed to induce photoluminescence in an unirradiated glass. Thermal behaviour of the two centers was also different. After heating the glass for 5 min at a number of temperatures, a gradual increase in RPL was observed up to 200 0 C. Above 200 0 C, the thermal treatment bleached the RPL. The optical absorbance was bleached from room temperature upwards. (U.K.)

  1. Plasmonic enhancement of UV emission from ZnO thin films induced by Al nano-concave arrays

    International Nuclear Information System (INIS)

    Norek, Małgorzata; Łuka, Grzegorz; Włodarski, Maksymilian

    2016-01-01

    Highlights: • Al nano-concave arrays with different interpore distance (D c ) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al 2 O 3 spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D c and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D c ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D c ) were used to enhance the ultraviolet light emission from ZnO thin films. Two sets of samples were prepared: in the first set the thin ZnO films were deposited directly on Al nanoconcaves (the Al/ZnO samples) and in the second set a 10 nm − Al 2 O 3 spacer was placed between the textured Al and the ZnO films (the Al/Al 2 O 3 -ALD/ZnO samples). In the Al/ZnO samples the enhancement was limited by a nonradiative energy dissipation due to the Ohmic loss in the Al metal. However, for the ZnO layer deposited directly on Al nanopits synthesized at 150 V (D c = 333 ± 18 nm), the largest 9-fold enhancement was obtained by achieving the best energy fit between the near band-edge (NBE) emission from ZnO and the λ (0,1) SPP resonance mode. In the Al/Al 2 O 3 -ALD/ZnO samples the amplification of the UV emission was smaller than in the Al/ZnO samples due to a big energy mismatch between the NBE emission and the λ (0,1) plasmonic mode. The results obtained in this work indicate that better tuning of the NBE − λ (0,1) SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al 2 O 3 -ALD/ZnO system such as Al nano-concave spacing and the thickness of the corresponding layer. This approach will reduce the negative influence of the non-radiative plasmonic modes and most likely will lead to further enhancement of the SP-modulated UV emission from ZnO thin films.

  2. Plasmonic enhancement of UV emission from ZnO thin films induced by Al nano-concave arrays

    Energy Technology Data Exchange (ETDEWEB)

    Norek, Małgorzata, E-mail: mnorek@wat.edu.pl [Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Łuka, Grzegorz [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland); Włodarski, Maksymilian [Institute of Optoelectronics, Military University of Technology, Str. Kaliskiego 2, 00-908 Warszawa (Poland)

    2016-10-30

    Highlights: • Al nano-concave arrays with different interpore distance (D{sub c}) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al{sub 2}O{sub 3} spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D{sub c} and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D{sub c} ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D{sub c}) were used to enhance the ultraviolet light emission from ZnO thin films. Two sets of samples were prepared: in the first set the thin ZnO films were deposited directly on Al nanoconcaves (the Al/ZnO samples) and in the second set a 10 nm − Al{sub 2}O{sub 3} spacer was placed between the textured Al and the ZnO films (the Al/Al{sub 2}O{sub 3}-ALD/ZnO samples). In the Al/ZnO samples the enhancement was limited by a nonradiative energy dissipation due to the Ohmic loss in the Al metal. However, for the ZnO layer deposited directly on Al nanopits synthesized at 150 V (D{sub c} = 333 ± 18 nm), the largest 9-fold enhancement was obtained by achieving the best energy fit between the near band-edge (NBE) emission from ZnO and the λ{sub (0,1)} SPP resonance mode. In the Al/Al{sub 2}O{sub 3}-ALD/ZnO samples the amplification of the UV emission was smaller than in the Al/ZnO samples due to a big energy mismatch between the NBE emission and the λ{sub (0,1)} plasmonic mode. The results obtained in this work indicate that better tuning of the NBE − λ{sub (0,1)} SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al{sub 2}O{sub 3}-ALD/ZnO system such as Al nano-concave spacing and the thickness of the corresponding layer. This approach will reduce the negative influence of the non-radiative plasmonic modes and most likely will lead to further

  3. Noise Characterization and Performance of MODIS Thermal Emissive Bands

    Science.gov (United States)

    Madhavan, Sriharsha; Xiong, Xiaoxiong; Wu, Aisheng; Wenny, Brian; Chiang, Kwofu; Chen, Na; Wang, Zhipeng; Li, Yonghong

    2016-01-01

    The MODerate-resolution Imaging Spectroradiometer (MODIS) is a premier Earth-observing sensor of the early 21st century, flying onboard the Terra (T) and Aqua (A) spacecraft. Both instruments far exceeded their six-year design life and continue to operate satisfactorily for more than 15 and 13 years, respectively. The MODIS instrument is designed to make observations at nearly a 100% duty cycle covering the entire Earth in less than two days. The MODIS sensor characteristics include a spectral coverage from 0.41micrometers to 14.4 micrometers, of which those wavelengths ranging from 3.7 micrometers to 14.4 micrometers cover the thermal infrared region which is interspaced in 16 thermal emissive bands (TEBs). Each of the TEB contains ten detectors which record samples at a spatial resolution of 1 km. In order to ensure a high level of accuracy for the TEB-measured top-of-atmosphere radiances, an onboard blackbody (BB) is used as the calibration source. This paper reports the noise characterization and performance of the TEB on various counts. First, the stability of the onboard BB is evaluated to understand the effectiveness of the calibration source. Next, key noise metrics such as the noise equivalent temperature difference and the noise equivalent dn difference (NEdN) for the various TEBs are determined from multiple temperature sources. These sources include the nominally controlled BB temperature of 290 K for T-MODIS and 285 K for A-MODIS, as well as a BB warm up-cool down cycle that is performed over a temperature range from roughly 270 to 315 K. The space-view port that measures the background signal serves as a viable cold temperature source for measuring noise. In addition, a well characterized Earth-view target, the Dome Concordia site located in the Antarctic plateau, is used for characterizing the stability of the sensor, indirectly providing a measure of the NEdN. Based on this rigorous characterization, a list of the noisy and inoperable detectors for

  4. Power electronics solution to dust emissions from thermal power plants

    Directory of Open Access Journals (Sweden)

    Vukosavić Slobodan

    2010-01-01

    Full Text Available Thermal power stations emit significant amounts of fly ash and ultra fine particles into the atmosphere. Electrostatic precipitators (ESP or electro filters remove flying ashes and fine particles from the flue gas before passing the gas into the chimney. Maximum allowable value of dust is 50 mg/m3 and it requires that the efficiency of the ESPs better than 99 %, which calls for an increase of active surface of the electrodes, hence increasing the filter volume and the weight of steel used for the filter. In previous decades, electrostatic precipitators in thermal power plants were fed by thyristor controlled, single phase fed devices having a high degree of reliability, but with a relatively low collection efficiency, hence requiring large effective surface of the collection plates and a large weight of steel construction in order to achieve the prescribed emission limits. Collection efficiency and energy efficiency of the electrostatic precipitator can be increased by applying high frequency high voltage power supply (HF HV. Electrical engineering faculty of the University of Belgrade (ETF has developed technology and HF HV equipment for the ESP power supply. This solution was subjected to extensive experimental investigation at TE Morava from 2008 to 2010. High frequency power supply is proven to reduce emission two times in controlled conditions while increasing energy efficiency of the precipitator, compared to the conventional thyristor controlled 50Hz supply. Two high frequency high voltage unit AR70/1000 with parameters 70 kV and 1000 mA are installed at TE Morava and thoroughly testes. It was found that the HF HV power supply of the ESP at TE Morava increases collection efficiency so that emission of fine particles and flying ashes are halved, brought down to only 50 % of the emissions encountered with conventional 50 Hz thyristor driven power supplies. On the basis of this study, conclusion is drawn that the equipment comprising HF HV

  5. Emissions, energy return and economics from utilizing forest residues for thermal energy compared to onsite pile burning

    Science.gov (United States)

    Greg Jones; Dan Loeffler; Edward Butler; Woodam Chung; Susan Hummel

    2010-01-01

    The emissions from delivering and burning forest treatment residue biomass in a boiler for thermal energy were compared with onsite disposal by pile-burning and using fossil fuels for the equivalent energy. Using biomass for thermal energy reduced carbon dioxide emissions on average by 39 percent and particulate matter emissions by 89 percent for boilers with emission...

  6. Status of thermal power generation in India-Perspectives on capacity, generation and carbon dioxide emissions

    International Nuclear Information System (INIS)

    Ghosh, Subhodip

    2010-01-01

    India's reliance on fossil-fuel based electricity generation has aggravated the problem of high carbon dioxide (CO 2 ) emissions from combustion of fossil fuels, primarily coal, in the country's energy sector. The objective of this paper is to analyze thermal power generation in India for a four-year period and determine the net generation from thermal power stations and the total and specific CO 2 emissions. The installed generating capacity, net generation and CO 2 emissions figures for the plants have been compared and large generators, large emitters, fuel types and also plant vintage have been identified. Specific emissions and dates of commissioning of plants have been taken into account for assessing whether specific plants need to be modernized. The focus is to find out areas and stations which are contributing more to the total emissions from all thermal power generating stations in the country and identify the overall trends that are emerging.

  7. Ohmic ion temperature and thermal diffusivity profiles from the JET neutron emission profile monitor

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, B. (ENEA, Frascati (Italy). Centro Ricerche Energia); Marcus, F.B.; Conroy, S.; Jarvis, O.N.; Loughlin, M.J.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking); Adams, J.M.; Watkins, N. (AEA Industrial Technology, Harwell (United Kingdom))

    1993-10-01

    The JET neutron emission profile monitor was used to study ohmically heated deuterium discharges. The radial profile of the neutron emissivity is deduced from the line-integral data. The profiles of ion temperature, T[sub i], and ion thermal diffusivity, [chi][sub i], are derived under steady-state conditions. The ion thermal diffusivity is higher than, and its scaling with plasma current opposite to, that predicted by neoclassical theory. (author).

  8. Ohmic ion temperature and thermal diffusivity profiles from the JET neutron emission profile monitor

    International Nuclear Information System (INIS)

    Esposito, B.

    1993-01-01

    The JET neutron emission profile monitor was used to study ohmically heated deuterium discharges. The radial profile of the neutron emissivity is deduced from the line-integral data. The profiles of ion temperature, T i , and ion thermal diffusivity, χ i , are derived under steady-state conditions. The ion thermal diffusivity is higher than, and its scaling with plasma current opposite to, that predicted by neoclassical theory. (author)

  9. Vanadium Dioxide as a Natural Disordered Metamaterial: Perfect Thermal Emission and Large Broadband Negative Differential Thermal Emittance

    Directory of Open Access Journals (Sweden)

    Mikhail A. Kats

    2013-10-01

    Full Text Available We experimentally demonstrate that a thin (approximately 150-nm film of vanadium dioxide (VO_{2} deposited on sapphire has an anomalous thermal emittance profile when heated, which arises because of the optical interaction between the film and the substrate when the VO_{2} is at an intermediate state of its insulator-metal transition (IMT. Within the IMT region, the VO_{2} film comprises nanoscale islands of the metal and dielectric phases and can thus be viewed as a natural, disordered metamaterial. This structure displays “perfect” blackbodylike thermal emissivity over a narrow wavelength range (approximately 40  cm^{-1}, surpassing the emissivity of our black-soot reference. We observe large broadband negative differential thermal emittance over a >10 °C range: Upon heating, the VO_{2}-sapphire structure emits less thermal radiation and appears colder on an infrared camera. Our experimental approach allows for a direct measurement and extraction of wavelength- and temperature-dependent thermal emittance. We anticipate that emissivity engineering with thin-film geometries comprising VO_{2} and other thermochromic materials will find applications in infrared camouflage, thermal regulation, and infrared tagging and labeling.

  10. THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Zabalza, V.; Paredes, J. M. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Marti i Franques 1, E08028 Barcelona (Spain); Bosch-Ramon, V., E-mail: vzabalza@am.ub.es [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

    2011-12-10

    Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

  11. AURORA on MEGSAT 1 a photon counting observatory for the Earth UV night-sky background and Aurora emission

    CERN Document Server

    Monfardini, A; Stalio, R; Mahne, N; Battiston, R; Menichelli, M; Mazzinghi, P

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 sup + N sub 2 line (lambda sub c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 sup - N sup + sub 2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h sub a sub p sub o sub g sub e sub e =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of...

  12. AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

    International Nuclear Information System (INIS)

    Monfardini, A.; Trampus, P.; Stalio, R.; Mahne, N.; Battiston, R.; Menichelli, M.; Mazzinghi, P.

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 + N 2 line (λ c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 - N + 2 ), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h apogee =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of the techniques adopted is given in this paper

  13. On the Absence of Non-thermal X-Ray Emission around Runaway O Stars

    Energy Technology Data Exchange (ETDEWEB)

    Toalá, J. A. [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taipei 10617, Taiwan (China); Oskinova, L. M. [Institute for Physics and Astronomy, University of Potsdam, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States)

    2017-04-01

    Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ -ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emission from bow shocks using archived XMM-Newton observations for a clean sample of six well-determined runaway O stars. We find that none of these objects present diffuse X-ray emission associated with their bow shocks, similarly to previous X-ray studies toward ζ Oph and BD+43°3654. We carefully investigated multi-wavelength observations of AE Aur and could not confirm previous findings of non-thermal X-rays. We conclude that so far there is no clear evidence of non-thermal extended emission in bow shocks around runaway O stars.

  14. Detector array for measurement of high-frequency fluctuations in visible and near-UV emission from tokamaks

    International Nuclear Information System (INIS)

    Hurwitz, P.D.; Hall, B.F.; Rowan, W.L.

    1992-01-01

    We developed an imaging detector to measure high-frequency fluctuations in visible and near-UV emission from tokamaks. The detector is intended for the study of plasma turbulence, mhd phenomena, and edge-localized modes. Particularly in the first two applications, it will complement existing techniques by providing higher spatial resolution as well as measurement capability in otherwise inaccessible regions of the plasma. The device consists of an optical system, a linear array of 32 photodiodes, and an amplifier for each photodiode. The amplifiers have a transimpedance gain of 10 5 --10 6 and the frequency response is flat to 100 kHz. Experience with this device has shown that optical imaging systems can be easily designed and tailored to a specific measurement because of the small size and close spacing of the individual light-sensitive elements. The device has been successfully tested on TEXT-U in measurements of H α fluctuations

  15. Full-energy-chain analysis of greenhouse gas emissions for solar thermal electric power generation systems

    International Nuclear Information System (INIS)

    Norton, B.; Lawson, W.R.

    1997-01-01

    Technical attributes and environmental impacts of solar thermal options for centralized electricity generation are discussed. In particular, the full-energy-chain, including embodied energy and energy production, is considered in relation to greenhouse gas emission arising from solar thermal electricity generation. Central receiver, parabolic dish, parabolic trough and solar pond systems are considered. (author)

  16. Io's UV-V Eclipse Emission: Implications for Pele-type Plumes

    Science.gov (United States)

    Moore, C. H.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.

    2010-03-01

    Simulations of Io's NUV-V emission in eclipse show that S2-rich giant plumes' S2 concentrations and activity levels effect the absolute brightness and the east/west intensity ratio across Io allowing for plume activity to be determined from observed spectra.

  17. White light emission from Tm3+/Dy3+ co-doped oxyfluoride germanate glasses under UV light excitation

    International Nuclear Information System (INIS)

    Lakshminarayana, G.; Yang Hucheng; Qiu Jianrong

    2009-01-01

    In this paper, we report on the absorption and photoluminescence properties of Tm 3+ /Dy 3+ ions co-doped oxyfluoride germanate glasses for white light emission. The X-ray diffraction (XRD) and differential thermal analysis (DTA) profiles of the host glass have been carried out to confirm its structure and thermal stability. From the measured absorption spectra, Judd-Ofelt (J-O) intensity parameters (Ω 2 , Ω 4 and Ω 6 ) have been evaluated for Tm 3+ and Dy 3+ ions. A combination of blue, yellow and red emissions has emerged in these glasses, which allows the observation of bright white light when the glasses are excited by the ultraviolet light. The white light luminescence colour could be changed by varying the excitation wavelength. Also, various colours of luminescence, including white light, can be easily tuned by adjusting the concentrations of Tm 3+ or Dy 3+ ions in the co-doped glasses. Concentration quenching effect was also investigated and possible energy transfer mechanism from Dy 3+ →Tm 3+ ions was explained which is also confirmed by the decay lifetime measurements. - Graphical Abstract: A combination of blue, yellow and red emissions has emerged from Tm 3+ /Dy 3+ co-doped glasses, which allows the observation of bright white light and makes them as excellent candidates applicable in the solid-state multi-colour three-dimensional display.

  18. Volcanism on Io: The Galileo NIMS Io Thermal Emission Database (NITED)

    Science.gov (United States)

    Davies, A. G.; Veeder, G. J.; Matson, D. L.; Johnson, T. V.

    2011-12-01

    In order to determine the magnitude of thermal emission from Io's volcanoes and variability with time at local, regional and global scales, we have calculated the 4.7 or 5 μm radiant flux for every hot spot in every Galileo Near Infrared Mapping Spectrometer (NIMS) observation obtained during the Galileo mission between June 1996 and October 2001. The resulting database contains over 1000 measurements of radiant flux, corrected for emission angle, range to target, and, where necessary, incident sunlight. Io's volcanoes produce the most voluminous and most powerful eruptions in the Solar System [1] and NIMS was the ideal instrument for measuring thermal emission from these volcanoes (see [1, 2]). NIMS covered the infrared from 0.7 to 5.2 μm, so measurement of hot spot thermal emission at ~5 μm was possible even in daytime observations. As part of a campaign to quantify magnitude and variability of volcanic thermal emission [1, 3-5] we examined the entire NIMS dataset (196 observations). The resulting NIMS Io Thermal Emission Database (NITED) allows the charting of 5-μm thermal emission at individual volcanoes, identifying individual eruption episodes, and enabling the comparison of activity at different hot spots [e.g., 6] and different regions of Io. Some ionian hot spots were detected only once or twice by NIMS (e.g., Ah Peku Patera, seen during I32), but most were detected many times (e.g., Culann, Tupan and Zamama, [6]). For example, the database contains over 40 observations of Loki Patera (some at high emission angle, and two partial observations). There are 55 observations of Pele. The 27 nighttime observations of Pele show a remarkably steady 5-μm radiant flux of 35 ± 12 GW/μm. There are 34 observations of Pillan, which erupted violently in 1997. Although in many observations low spatial resolution makes it difficult to separate hot spot pairs such as Susanoo Patera and Mulungu Patera; Tawhaki Patera and Hi'iaka Patera; and Janus Patera and Kanehekili

  19. IR, 1H-NMR, UV-Vis AND THERMAL STUDIES ON THE ...

    African Journals Online (AJOL)

    Preferred Customer

    Charge-transfer complexes using organic species are intensively studied [6, .... 1242 ms. 1698 s. 1647 s. 1608 vs. 1530 s. 1501 s. 1446 mw. 1364 s. 1318 vs .... thermal decomposition process of Rh6G/iodine complex is non-spontaneous, i.e..

  20. Microstudies on thermal and UV treated silicone-acrylic paints with different pigment volume concentrations

    International Nuclear Information System (INIS)

    Chew, K.W.; Abdul Kariem Arof; Yahaya, A.H.; Yahya, R.; Puteh, R.

    2002-01-01

    The effect of pigment volume concentration (PVC) on morphology of pigment particles employed in the silicone-acrylic compositions suitable for high temperature corrosion protection application, has been investigated using SEM. Silicone-acrylic based paints with 50% silicone resin have been selected to prepare paints with PVC values from 10% to 60%. The paints were applied on mild steel panels of size of 5 cm x 7.5 cm. After curing for one week, the panels were subjected to 24 hours of heating ranging from room temperature up to 300 degree C and 400 hours of UV weathering. After the corrosion test, SEM micrographs were taken to investigate the gloss, rusting and adhesion properties of the coating films. (Author)

  1. Te(R,t) Measurements using Electron Bernstein Wave Thermal Emission on NSTX

    International Nuclear Information System (INIS)

    Diem, S.J.; Taylor, G.; Efthimion, P.C.; LeBlanc, B.P.; Carter, M.; Caughman, J.; Wilgen, J.B.; Harvey, R.W.; Preinhaelter, J.; Urban, J.

    2006-01-01

    The National Spherical Torus Experiment (NSTX) routinely studies overdense plasmas with n e of (1-5) x 10 19 m -3 and total magnetic field of e measurement. A significant upgrade to the previous NSTX EBW emission diagnostic to measure thermal EBW emission via the oblique B-X-O mode conversion process has been completed. The new EBW diagnostic consists of two remotely steerable, quad-ridged horn antennas, each of which is coupled to a dual channel radiometer. Fundamental (8-18 GHz) and second and third harmonic (18-40 GHz) thermal EBW emission and polarization measurements can be obtained simultaneously.

  2. UV-radiation-induced electron emission by hormones. Hypothesis for specific communication mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Getoff, Nikola [University of Vienna, Department of Nutritional Sciences, Section Radiation Biology, Althanstr. 14, UZAII, A-1090 Vienna (Austria)], E-mail: nikola.getoff@univie.ac.at

    2009-11-15

    The highlights of recently observed electron emission from electronically excited sexual hormones (17{beta}-estradiol, progesterone, testosterone) and the phytohormone genistein in polar media are briefly reviewed. The electron yield, Q(e{sub aq}{sup -}), dependence from substrate concentration, hormone structure, polarity of solvent, absorbed energy and temperature are discussed. The hormones reactivity with e{sub aq}{sup -} and efficiency in electron transfer ensure them the ability to communicate with other biological systems in an organism. A hypothesis is presented for the explanation of the mechanisms of the distinct recognition of signals transmitted by electrons, originating from different types of hormones to receiving centres. Biological consequences of the electron emission in respect to cancer are mentioned.

  3. Variable Emissive Smart Radiator for Dynamic Thermal Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Trending towards reduced power and mass budget on satellites with a longer mission life, there is a need for a reliable thermal control system that is more efficient...

  4. Programmable thermal emissivity structures based on bioinspired self-shape materials

    Science.gov (United States)

    Athanasopoulos, N.; Siakavellas, N. J.

    2015-12-01

    Programmable thermal emissivity structures based on the bioinspired self-shape anisotropic materials were developed at macro-scale, and further studied theoretically at smaller scale. We study a novel concept, incorporating materials that are capable of transforming their shape via microstructural rearrangements under temperature stimuli, while avoiding the use of exotic shape memory materials or complex micro-mechanisms. Thus, programmed thermal emissivity behaviour of a surface is achievable. The self-shape structure reacts according to the temperature of the surrounding environment or the radiative heat flux. A surface which incorporates self-shape structures can be designed to quickly absorb radiative heat energy at low temperature levels, but is simultaneously capable of passively controlling its maximum temperature in order to prevent overheating. It resembles a “game” of colours, where two or more materials coexist with different values of thermal emissivity/ absorptivity/ reflectivity. The transformation of the structure conceals or reveals one of the materials, creating a surface with programmable - and therefore, variable- effective thermal emissivity. Variable thermal emissivity surfaces may be developed with a total hemispherical emissivity ratio (ɛEff_H/ɛEff_L) equal to 28.

  5. Hard x ray imaging and the relative contribution of thermal and nonthermal emission in flares

    International Nuclear Information System (INIS)

    Holman, G.D.

    1986-01-01

    The question of whether the impulsive 25 to 100 keV x ray emission from solar flares is thermal or nonthermal has been a long-standing controversy. Both thermal and nonthermal (beam) models have been developed and applied to the hard x ray data. It now seems likely that both thermal and nonthermal emission have been observed at hard x ray energies. The Hinotori classification scheme, for example, is an attempt to associate the thermal-nonthermal characteristics of flare hard x ray emission with other flare properties. From a theoretical point of view, it is difficult to generate energetic, nonthermal electrons without dumping an equal or greater amount of energy into plasma heating. On the other hand, any impulsive heating process will invariably generate at least some nonthermal particles. Hence, strictly speaking, although thermal or nonthermal emission may dominate the hard x ray emission in a given energy range for a given flare, there is no such thing as a purely thermal or nonthermal flare mechanism

  6. UV light induced red emission in Eu3+-doped zincborophosphate glasses

    Science.gov (United States)

    Hima Bindu, S.; Siva Raju, D.; Vinay Krishna, V.; Rajavardhana Rao, T.; Veerabrahmam, K.; Linga Raju, Ch.

    2016-12-01

    This paper reports the preparation of transparent zincborophosphate (ZBP) glasses doped with Eu3+ ions by the conventional melt quenching technique. The prepared glasses were characterized using powder XRD, FTIR, optical absorption, photoluminescence and decay curves. Judd-Ofelt (JO) intensity parameters calculated under various constraints using absorption and emission spectra. These JO intensity parameters have been used to predict the radiative properties such as radiative life time, branching ratios and stimulated emission cross section of the 5D0→7FJ (J = 0-4) transitions. Decay curves for the 5D0 level of Eu3+ ions shows single exponential for all concentrations. Luminescence properties of 5D0→7F2 transitions of Eu3+ions have revealed that the present ZBP:Eu3+ glasses have significant in optical applications at around 613 nm. An intense red luminescence has been observed due to 5D0→7F2 transition of Eu3+ ion in these glasses. From the CIE color coordinate diagram, it is observed that the present glass system is prominent material for red emission.

  7. The Swift BAT Perspective on Non-Thermal Emission in HIFLUGCS Galaxy Clusters

    Science.gov (United States)

    Wik, Daniel R.

    2011-01-01

    The search for diffuse non-thermal, inverse Compton (IC) emission from galaxy clusters at hard X-ray energies has been underway for many years, with most detections being either of low significance or controversial. Until recently, comprehensive surveys of hard X-ray emission from clusters were not possible; instead, individually proposed-for. long observations would be collated from the archive. With the advent of the Swift BAT all sky survey, any c1u,;ter's emission above 14 keV can be probed with nearly uniform sensitivity. which is comparable to that of RXTE, Beppo-SAX, and Suzaku with the 58-month version of the survey. In this work. we search for non-thermal excess emission above the exponentially decreasing, high energy thermal emission in the flux-limited HIFLUGCS sample. The BAT emission from many of the detected clusters is marginally extended; we are able to extract the total flux for these clusters using fiducial models for their spatial extent. To account for thermal emission at BAT energies, XMM-Newton EPIC spectra are extracted from coincident spatial regions so that both the thermal and non-thermal spectral components can be determined simultaneou,;ly in joint fits. We find marginally significant IC components in 6 clusters, though after closer inspection and consideration of systematic errors we are unable to claim a clear detection in any of them. The spectra of all clusters are also summed to enhance a cumulative non-thermal signal not quite detectable in individual clusters. After constructing a model based on single temperature

  8. Early UV emission from disc-originated matter (DOM) in Type Ia supernovae in the double-degenerate scenario

    Science.gov (United States)

    Levanon, Naveh; Soker, Noam

    2017-09-01

    We show that the blue and UV excess emission in the first few days of some Type Ia supernovae (SNe Ia) can be accounted in the double-degenerate (DD) scenario by the collision of the SN ejecta with circumstellar matter that was blown by the accretion disc formed during the merger process of the two white dwarfs (WDs). We assume that in cases of excess early light, the disc blows the circumstellar matter, that we term disc-originated matter (DOM), hours to days before explosion. To perform our analysis, we first provide a model-based definition for early excess light, replacing the definition of excess light relative to a power-law fit to the rising luminosity. We then examine the light curves of the SNe Ia iPTF14atg and SN 2012cg, and find that the collision of the ejecta with a DOM in the frame of the DD scenario can account for their early excess emission. Thus, early excess light does not necessarily imply the presence of a stellar companion in the frame of the single-degenerate scenario. Our findings further increase the variety of phenomena that the DD scenario can account for, and emphasize the need to consider all different SN Ia scenarios when interpreting observations.

  9. Solar UV irradiation-induced production of N2O from plant surfaces - low emissions rates but all over the world.

    Science.gov (United States)

    Mikkelsen, T. N.; Bruhn, D.; Ambus, P.

    2016-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2 h-1, mostly due to the UV component. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  10. Wall temperature measurements using a thermal imaging camera with temperature-dependent emissivity corrections

    International Nuclear Information System (INIS)

    McDaid, Chloe; Zhang, Yang

    2011-01-01

    A methodology is presented whereby the relationship between temperature and emissivity for fused quartz has been used to correct the temperature values of a quartz impingement plate detected by an SC3000 thermal imaging camera. The methodology uses an iterative method using the initial temperature (obtained by assuming a constant emissivity) to find the emissivity values which are then put into the thermal imaging software and used to find the subsequent temperatures, which are used to find the emissivities, and so on until converged. This method is used for a quartz impingement plate that has been heated under various flame conditions, and the results are compared. Radiation losses from the plate are also calculated, and it is shown that even a slight change in temperature greatly affects the radiation loss. It is a general methodology that can be used for any wall material whose emissivity is a function of temperature

  11. Measurement of visible and UV emission from Energetic Neutral Atom Precipitation (ENAP), on Spacelab

    Science.gov (United States)

    Tinsley, B. A.

    1980-01-01

    The charge exchange of plasmaspheric ions and exospheric H and O and of solar wind ions with exospheric and interplanetary H are sources of precipitating neutrals whose faint emission may be observed by the imaging spectrometric observatory during dark periods of the SL-1 orbit. Measurements of the interactions of these precipitating atoms with the thermosphere are needed to evaluate the heating and ionization effects on the atmosphere as well as the selective loss of i energetic ions from the sources (predominantly the ring current).

  12. Preparation, flame retardancy and thermal behavior of a novel UV-curable coating containing phosphorus and nitrogen

    International Nuclear Information System (INIS)

    Xing Weiyi; Song Lei; Lv Pin; Jie Ganxin; Wang Xin; Lv Xiaoqi; Hu Yuan

    2010-01-01

    A novel phosphorus monomer, 2,2-dimethyl-1,3-propanediol acryloyloxyethyl phosphate (DPHA), has been synthesized through phosphorus oxychloride reacting with neopentyl glycol and 2-hydroxyethyl acrylate (HEA). Its structure was characterized by Fourier transform infrared spectroscopy (FTIR), 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR) and 31 P nuclear magnetic resonance spectroscopy ( 31 P NMR). A series of UV-curable resins were manufactured by blending DPHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratio. The fire performance was examined by Microscale Combustion Calorimetry (MCC). The results obtained from MCC indicated that the addition of DPHA to TGICA decreased the peak heat release rate (PHRR), heat release capacity (HRC) and total heat of combustion (THC). The char residues of the composites were observed by scanning electron microscopy (SEM). The thermal decomposition behavior of DPHA/TGICA composites was characterized by using thermogravimetric analysis/infrared spectrometry (TGA-IR). The test results indicated that when the weight ratio of DPHA: TGICA = 1/1, the onset temperature of the composite was highest and the largest char residue at 700 deg. C was observed. The change of chemical structure during the thermal degradation process was monitored by real-time FTIR analysis. TGA-IR results indicated that the evolved products were CO, CO 2 , water, NH 3 , carbonyl, phosphorus oxides and aromatic compounds according to the temperature of onset formation.

  13. Preparation, flame retardancy and thermal behavior of a novel UV-curable coating containing phosphorus and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Xing Weiyi [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China); Song Lei [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Lv Pin; Jie Ganxin [State Key Laboratory of Environmental Adaptability for Industrial Products, China National Electric Apparatus Research Institute, Guangzhou 510300 (China); Wang Xin; Lv Xiaoqi [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Hu Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China)

    2010-10-01

    A novel phosphorus monomer, 2,2-dimethyl-1,3-propanediol acryloyloxyethyl phosphate (DPHA), has been synthesized through phosphorus oxychloride reacting with neopentyl glycol and 2-hydroxyethyl acrylate (HEA). Its structure was characterized by Fourier transform infrared spectroscopy (FTIR), {sup 1}H nuclear magnetic resonance spectroscopy ({sup 1}H NMR) and {sup 31}P nuclear magnetic resonance spectroscopy ({sup 31}P NMR). A series of UV-curable resins were manufactured by blending DPHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratio. The fire performance was examined by Microscale Combustion Calorimetry (MCC). The results obtained from MCC indicated that the addition of DPHA to TGICA decreased the peak heat release rate (PHRR), heat release capacity (HRC) and total heat of combustion (THC). The char residues of the composites were observed by scanning electron microscopy (SEM). The thermal decomposition behavior of DPHA/TGICA composites was characterized by using thermogravimetric analysis/infrared spectrometry (TGA-IR). The test results indicated that when the weight ratio of DPHA: TGICA = 1/1, the onset temperature of the composite was highest and the largest char residue at 700 deg. C was observed. The change of chemical structure during the thermal degradation process was monitored by real-time FTIR analysis. TGA-IR results indicated that the evolved products were CO, CO{sub 2}, water, NH{sub 3}, carbonyl, phosphorus oxides and aromatic compounds according to the temperature of onset formation.

  14. Thermal edible oil evaluation by UV-Vis spectroscopy and chemometrics.

    Science.gov (United States)

    Gonçalves, Rhayanna P; Março, Paulo H; Valderrama, Patrícia

    2014-11-15

    Edible oils such as colza, corn, sunflower, soybean and olive were analysed by UV-Vis spectroscopy and Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS). When vegetable oils were heated at high temperatures (frying), oxidation products were formed which were harmful to human health in addition to degrading the antioxidants present, and this study aimed to evaluate tocopherol (one antioxidant present in oils) and the behaviour of oxidation products in edible oils. The MCR-ALS results showed that the degradation started at 110°C and 85°C, respectively, for sunflower and colza oils, while tocopherol concentration decreased and oxidation products increased starting at 70°C in olive oil. In soybean and corn oils, tocopherol concentration started to decrease and oxidation products increased at 50°C. The results suggested that sunflower, colza and olive oils offered more resistance to increasing temperatures, while soybean and corn oils were less resistant. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Evaluation of drought and UV radiation impacts on above-ground biomass of mountain grassland by spectral reflectance and thermal imaging techniques

    Czech Academy of Sciences Publication Activity Database

    Novotná, Kateřina; Klem, Karel; Holub, Petr; Rapantová, Barbora; Urban, Otmar

    2016-01-01

    Roč. 9, 1-2 (2016), s. 21-30 ISSN 1803-2451 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : above-ground biomass * drought stress * grassland * UV radiation * precipitation * spectral reflectance * thermal imaging Subject RIV: EH - Ecology, Behaviour

  16. Thermal emissivity analysis of a GEMINI 8-meter telescopes design

    Science.gov (United States)

    St. Clair Dinger, Ann

    1993-01-01

    The GEMINI 8-meter Telescopes Project is designing twin 8-meter telescopes to be located in Hawaii and Chile. The GEMINI telescopes will have interchangeable secondary mirrors for use in the visible and IR. The APART/PADE program is being used to evaluate the effective IR emissivity of the IR configuration plus enclosure as a function of mirror contamination at three IR wavelengths. The goal is to design a telescope whose effective IR emissivity is no more than 2 percent when the mirrors are clean.

  17. Performance evaluation of four directional emissivity analytical models with thermal SAIL model and airborne images.

    Science.gov (United States)

    Ren, Huazhong; Liu, Rongyuan; Yan, Guangjian; Li, Zhao-Liang; Qin, Qiming; Liu, Qiang; Nerry, Françoise

    2015-04-06

    Land surface emissivity is a crucial parameter in the surface status monitoring. This study aims at the evaluation of four directional emissivity models, including two bi-directional reflectance distribution function (BRDF) models and two gap-frequency-based models. Results showed that the kernel-driven BRDF model could well represent directional emissivity with an error less than 0.002, and was consequently used to retrieve emissivity with an accuracy of about 0.012 from an airborne multi-angular thermal infrared data set. Furthermore, we updated the cavity effect factor relating to multiple scattering inside canopy, which improved the performance of the gap-frequency-based models.

  18. A combined plant and reaction chamber setup to investigate the effect of pollution and UV-B radiation on biogenic emissions

    Science.gov (United States)

    Timkovsky, J.; Gankema, P.; Pierik, R.; Holzinger, R.

    2012-12-01

    Biogenic emissions account for almost 90% of total non-methane organic carbon emissions in the atmosphere. The goal of this project is to study the effect of pollution (ozone, NOx) and UV radiation on the emission of real plants. We have designed and built a setup where we combine plant chambers with a reaction chamber (75L volume) allowing the addition of pollutants at different locations. The main analytical tool is a PTR-TOF-MS instrument that can be optionally coupled with a GC system for improved compound identification. The setup is operational since March 2012 and first measurements indicate interesting results, three types of experiments will be presented: 1. Ozonolysis of b-pinene. In this experiment the reaction chamber was flushed with air containing b-pinene at approximate levels of 50 nmol/mol. After ~40 min b-pinene levels reached equilibrium in the reaction chamber and a constant supply of ozone was provided. Within 30 minutes this resulted in a 10 nmol/mol decrease of b-pinene levels in accordance with a reaction rate constant of 1.5*10-17 cm3molec-1s-1 and a residence time of 10 minutes in the reaction chamber. In addition we observed known oxidation products such as formaldehyde, acetone, and nopinone the molar yields of which were also in accordance with reported values. 2. Ozonolysis of biogenic emissions from tomato plants. The air containing the emissions from tomato plants was supplied to the reaction chamber. After adding ozone we observed the decrease of monoterpene concentrations inside the reaction chamber. The observed decrease is consistent for online PTR-MS and GC/PTR-MS measurements. Several ozonolysis products have been observed in the chamber. 3. The effect of UV-B radiation on biogenic emissions of tomato plants. Tomato plants were exposed to UV-B radiation and their emissions measured during and after the treatment. We observed significant changes in the emissions of volatile organic compounds, with specific compounds increasing

  19. A thermal microjet system with tapered micronozzles fabricated by inclined UV lithography for transdermal drug delivery

    Science.gov (United States)

    Yoon, Yong-Kyu; Park, Jung-Hwan; Lee, Jeong-Woo; Prausnitz, Mark R.; Allen, Mark G.

    2011-02-01

    Transdermal drug delivery can be enabled by various methods that increase the permeability of the skin's outer barrier of stratum corneum, including skin exposure to heat and chemical enhancers, such as ethanol. Combining these approaches for the first time, in this study we designed a microdevice consisting of an array of microchambers filled with ethanol that is vaporized using an integrated microheater and ejected through a micronozzle contacting the skin surface. In this way, we hypothesize that the hot ethanol vapor can increase skin permeability upon contacting the skin surface. The tapered micronozzle and the microchamber designed for this application were realized using proximity-mode inclined rotational ultraviolet lithography, which facilitates easy fabrication of complex three-dimensional structures, convenient integration with other functional layers, low fabrication cost, and mass production. The resulting device had a micronozzle with an orifice inner and outer diameter of 220 and 320 µm, respectively, and an extruded height of 250 µm. When the microchamber was filled with an ethanol gel and activated, the resulting ethanol vapor jet increased the permeability of human cadaver epidermis to a model compound, calcein, by approximately 17 times, which is attributed to thermal and chemical disruption of stratum corneum structure. This thermal microjet system can serve as a tool not only for transdermal drug delivery, but also for a variety of biomedical applications.

  20. A thermal microjet system with tapered micronozzles fabricated by inclined UV lithography for transdermal drug delivery

    International Nuclear Information System (INIS)

    Yoon, Yong-Kyu; Park, Jung-Hwan; Lee, Jeong-Woo; Prausnitz, Mark R; Allen, Mark G

    2011-01-01

    Transdermal drug delivery can be enabled by various methods that increase the permeability of the skin's outer barrier of stratum corneum, including skin exposure to heat and chemical enhancers, such as ethanol. Combining these approaches for the first time, in this study we designed a microdevice consisting of an array of microchambers filled with ethanol that is vaporized using an integrated microheater and ejected through a micronozzle contacting the skin surface. In this way, we hypothesize that the hot ethanol vapor can increase skin permeability upon contacting the skin surface. The tapered micronozzle and the microchamber designed for this application were realized using proximity-mode inclined rotational ultraviolet lithography, which facilitates easy fabrication of complex three-dimensional structures, convenient integration with other functional layers, low fabrication cost, and mass production. The resulting device had a micronozzle with an orifice inner and outer diameter of 220 and 320 µm, respectively, and an extruded height of 250 µm. When the microchamber was filled with an ethanol gel and activated, the resulting ethanol vapor jet increased the permeability of human cadaver epidermis to a model compound, calcein, by approximately 17 times, which is attributed to thermal and chemical disruption of stratum corneum structure. This thermal microjet system can serve as a tool not only for transdermal drug delivery, but also for a variety of biomedical applications.

  1. Characterizing the first historic eruption of Nabro, Eritrea: Insights from thermal and UV remote sensing

    Science.gov (United States)

    Sealing, Christine R.

    June 2011 saw the first historic eruption of Nabro volcano, one of an ongoing sequence of eruptions in the Afar-Red Sea region since 2005. It halted air travel in northern Africa, contaminated food and water sources, and displaced thousands from their homes. Due to its remote location, little was known about this event in terms of the quantity of erupted products and the timing and mechanisms of their emplacement. Geographic isolation, previous quiescence and regional civil unrest meant that this volcano was effectively unmonitored at the time of eruption, and opportunities for field study are limited. Using free, publicly available satellite data, I examined rates of lava effusion and SO2 emission in order to quantify the amount of erupted products and understand the temporal evolution of the eruption, as well as explore what information can be gleaned about eruption mechanisms using remote sensing data. These data revealed a bimodal eruption, beginning with explosive activity marked by high SO2 emission totalling 1824 - 2299 KT, and extensive ash fall of 270 - 440 km2. This gave way to a period of rapid effusion, producing a ˜17 km long lava flow, and a volume of ˜22.1 x 106 m3. Mass balance between the SO2 and lava flows reveals no sulfur 'excess', suggesting that nearly all of the degassed magma was extruded. The 2011 eruption of Nabro lasted nearly 6 weeks, and may be considered the second largest historic eruption in Africa. Work such as this highlights the importance of satellite remote sensing for studying and monitoring volcanoes, particularly those in remote regions that may be otherwise inaccessible.

  2. The First Historic Eruption of Nabro, Eritrea: Insights from Thermal and UV Satellite Data

    Science.gov (United States)

    Sealing, C. R.; Carn, S. A.; Harris, A. J. L.

    2015-12-01

    In June 2011, the first recorded eruption of Nabro volcano, took place at the border of Eritrea and Ethiopia. This eruption was the largest in what could be considered an ongoing sequence of eruptions in the Afar-Red Sea region since 2005. It halted air travel in northern Africa, contaminated food and water sources, and displaced thousands from their homes. Geographic isolation, previous quiescence, and regional civil unrest meant that this volcano was effectively unmonitored at the time of eruption, and opportunities for field study were limited. The purpose of this study is to explore the quantity of erupted products and the timing and mechanisms of their emplacement using predominantly free, publicly available satellite data. We use MODIS and OMI data to examine rates of lava effusion and SO2 emission, and quantify the amount of erupted products. We also examine published images from other satellites, such as ALI and SEVIRI in order to understand the temporal evolution of the eruption. Synthesizing these data, we then attempt to infer the mechanisms through which the eruption progressed. Examination of satellite data reveals a bimodal eruption, beginning with explosive activity marked by high SO2 emission totalling 1824 - 2299 KT, and extensive ash fall of 270 - 440 km2. This was followed by a period of rapid effusion, producing a ~17 km long lava flow, and a volume of ~22.1 x 106 m3. Mass balance between the SO2 and lava flows reveals no sulfur 'excess', suggesting that nearly all of the degassed magma was extruded. This eruption of Nabro continued for nearly 6 weeks, and may be considered the second largest historic eruption in Africa. This type of work highlights the effectiveness and importance of accessible satellite remote sensing data for the study of active volcanoes, particularly those in remote regions that may be otherwise inaccessible.

  3. Thermal Electron Bernstein Wave Emission Measurements on NST

    Czech Academy of Sciences Publication Activity Database

    Diem, S.J.; Taylor, G.; Efthimion, P.; LeBlanc, B.P.; Philips, C.K.; Caughman, J.; Wilgen, J.B.; Harvey, R.W.; Preinhaelter, Josef; Urban, Jakub

    2006-01-01

    Roč. 51, č. 7 (2006), s. 134 ISSN 0003-0503. [Annual Meeting of the Division of Plasma Physics/48th./. Philadelphia, Pennsylvania , 30.10.2006-3.11.2006] Institutional research plan: CEZ:AV0Z20430508 Keywords : Conversion * Emission * Tokamaks * Electron Bernstein waves * Simulation * MAST * NSTX Subject RIV: BL - Plasma and Gas Discharge Physics http://www.aps.org/meet/DPP06/baps/all_DPP06.pdf

  4. Mercury emissions control technologies for mixed waste thermal treatment

    International Nuclear Information System (INIS)

    Chambers, A.; Knecht, M.; Soelberg, N.; Eaton, D.

    1997-01-01

    EPA has identified wet scrubbing at low mercury feedrates, as well as carbon adsorption via carbon injection into the offgas or via flow through fixed carbon beds, as control technologies that can be used to meet the proposed Maximum Achievable Control Technology (MACT) rule limit for mercury emissions from hazardous waste incinerators. DOE is currently funding demonstrations of gold amalgamation that may also control mercury to the desired levels. Performance data from a variety of sources was reviewed to determine ranges of achievable mercury control. Preliminary costs were estimated for using these technologies to control mercury emissions from mixed waste incineration. Mercury emissions control for mixed waste incineration may need to be more efficient than for incineration of other hazardous wastes because of higher mercury concentrations in some mixed waste streams. However, mercury control performance data for wet scrubbing and carbon adsorption is highly variable. More information is needed to demonstrate control efficiencies that are achievable under various design and operating conditions for wet scrubbing, carbon adsorption, and gold amalgamation technologies. Given certain assumptions made in this study, capital costs, operating costs, and lifecycle costs for carbon injection, carbon beds, and gold amalgamation generally vary for different assumed mercury feedrates and for different offgas flowrates. Assuming that these technologies can in fact provide the necessary mercury control performance, each of these technologies may be less costly than the others for certain mercury feedrates and the offgas flowrates

  5. On-line monitoring on thermal shock damage of ceramics using acoustic emission

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Lee, Joon Hyun; Song, Sang Hun

    1999-01-01

    The objective of this paper is to investigate the degree of the thermal shock damage on alumina ceramic using acoustic emission technique. For this purpose, alumina ceramic specimen was heated in the elastic furnace and then was quenched into the water tank. When the specimen was quenched into water tank, a lot of micro-cracks were generated on the surface of specimen due to the thermal shock damage. In this study, acoustic emission technique was used to evaluate the elastic waves generated by the crack initiation and propagation on the surface of specimen. It was found that when the micro-crack was initiated on the surface of specimen, AE signals were the higher in amplitude than those of bubbling effect and crack propagation. A lot of AE events were generated at the first thermal shock, the number of AE events decreased gradually as the thermal shock cycle increased.

  6. Nitrogen oxides emissions from thermal power plants in china: current status and future predictions.

    Science.gov (United States)

    Tian, Hezhong; Liu, Kaiyun; Hao, Jiming; Wang, Yan; Gao, Jiajia; Qiu, Peipei; Zhu, Chuanyong

    2013-10-01

    Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unit-based method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.

  7. Energetic electron propagation in the decay phase of non-thermal flare emission

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jing; Yan, Yihua [Key Laboratory of Solar Activities, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Tsap, Yuri T., E-mail: huangj@nao.cas.cn [Crimean Astrophysical Observatory of Kyiv National Taras Shevchenko University, 98409 Crimea, Nauchny (Ukraine)

    2014-06-01

    On the basis of the trap-plus-precipitation model, the peculiarities of non-thermal emission in the decay phase of solar flares have been considered. The calculation formulas for the escape rate of trapped electrons into the loss cone in terms of time profiles of hard X-ray (HXR) and microwave (MW) emission have been obtained. It has been found that the evolution of the spectral indices of non-thermal emission depend on the regimes of the pitch angle diffusion of trapped particles into the loss cone. The properties of non-thermal electrons related to the HXR and MW emission of the solar flare on 2004 November 3 are studied with Nobeyama Radioheliograph, Nobeyama Radio Polarimeters, RHESSI, and Geostationary Operational Environmental Satellite observations. The spectral indices of non-thermal electrons related to MW and HXR emission remained constant or decreased, while the MW escape rate as distinguished from that of the HXRs increased. This may be associated with different diffusion regimes of trapped electrons into the loss cone. New arguments in favor of an important role of the superstrong diffusion for high-energy electrons in flare coronal loops have been obtained.

  8. Thermal and Nonthermal Emissions of a Composite Flare Derived from NoRH and SDO Observations

    Science.gov (United States)

    Lee, Jeongwoo; White, Stephen M.; Jing, Ju; Liu, Chang; Masuda, Satoshi; Chae, Jongchul

    2017-12-01

    Differential emission measure (DEM) derived from the extreme ultraviolet (EUV) lines of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory is used in the analysis of a solar flare observed by the Nobeyama Radioheliograph (NoRH). The target was a composite event consisting of an impulsive flare, SOL2015-06-21T01:42 (GOES class M2.0), and a gradual flare, SOL2015-06-21T02:36 (M2.6), for which separation of thermal plasma heating from nonthermal particle acceleration was of major interest. We have calculated the thermal free-free intensity maps with the AIA-derived DEM and compared them against the observed NoRH maps to attribute the difference to the nonthermal component. In this way, we were able to locate three distinct sources: the major source with thermal and nonthermal components mixed, a nonthermal source devoid of thermal particles, and a thermal source lacking microwave emission. Both the first and the second nonthermal sources produced impulsively rising 17 GHz intensities and moved away from the local magnetic polarization inversion lines in correlation with the flare radiation. In contrast, the thermal sources stay in fixed locations and show temporal variations of the temperature and emission measure uncorrelated with the flare radiation. We interpret these distinct properties as indicating that nonthermal sources are powered by magnetic reconnection and thermal sources passively receive energy from the nonthermal donor. The finding of these distinct properties between thermal and nonthermal sources demonstrates the microwave and EUV emission measure combined diagnostics.

  9. A comparative analysis of UV nadir-backscatter and infrared limb-emission ozone data assimilation

    Directory of Open Access Journals (Sweden)

    R. Dragani

    2016-07-01

    Full Text Available This paper presents a comparative assessment of ultraviolet nadir-backscatter and infrared limb-emission ozone profile assimilation. The Meteorological Operational Satellite A (MetOp-A Global Ozone Monitoring Experiment 2 (GOME-2 nadir and the ENVISAT Michelson Interferometer for Passive Atmospheric Sounding (MIPAS limb profiles, generated by the ozone consortium of the European Space Agency Climate Change Initiative (ESA O3-CCI, were individually added to a reference set of ozone observations and assimilated in the European Centre for Medium-Range Weather Forecasts (ECMWF data assimilation system (DAS. The two sets of resulting analyses were compared with that from a control experiment, only constrained by the reference dataset, and independent, unassimilated observations. Comparisons with independent observations show that both datasets improve the stratospheric ozone distribution. The changes inferred by the limb-based observations are more localized and, in places, more important than those implied by the nadir profiles, albeit they have a much lower number of observations. A small degradation (up to 0.25 mg kg−1 for GOME-2 and 0.5 mg kg−1 for MIPAS in the mass mixing ratio is found in the tropics between 20 and 30 hPa. In the lowermost troposphere below its vertical coverage, the limb data are found to be able to modify the ozone distribution with changes as large as 60 %. Comparisons of the ozone analyses with sonde data show that at those levels the assimilation of GOME-2 leads to about 1 Dobson Unit (DU smaller root mean square error (RMSE than that of MIPAS. However, the assimilation of MIPAS can still improve the quality of the ozone analyses and – with a reduction in the RMSE of up to about 2 DU – outperform the control experiment thanks to its synergistic assimilation with total-column ozone data within the DAS. High vertical resolution ozone profile observations are essential to accurately monitor and

  10. Strategies for emission reduction from thermal power plants.

    Science.gov (United States)

    Prisyazhniuk, Vitaly A

    2006-07-01

    Major polluters of man's environment are thermal power stations (TPS) and power plants, which discharge into the atmosphere the basic product of carbon fuel combustion, CO2, which results in a build-up of the greenhouse effect and global warm-up of our planet's climate. This paper is intended to show that the way to attain environmental safety of the TPS and to abide by the decisions of the Kyoto Protocol lies in raising the efficiency of the heat power stations and reducing their fuel consumption by using nonconventional thermal cycles. Certain equations have been derived to define the quantitative interrelationship between the growth of efficiency of the TPS, decrease in fuel consumption and reduction of discharge of dust, fuel combustion gases, and heat into the environment. New ideas and new technological approaches that result in raising the efficiency of the TPS are briefly covered: magneto-hydrodynamic resonance, the Kalina cycle, and utilizing the ambient heat by using, as the working medium, low-boiling substances.

  11. High aspect ratio silicon nanomoulds for UV embossing fabricated by directional thermal oxidation using an oxidation mask

    International Nuclear Information System (INIS)

    Chen, L Q; Chan-Park, Mary B; Yan, Y H; Zhang Qing; Li, C M; Zhang Jun

    2007-01-01

    Nanomoulding is simple and economical but moulds with nanoscale features are usually prohibitively expensive to fabricate because nanolithographic techniques are mostly serial and time-consuming for large-area patterning. This paper describes a novel, simple and inexpensive parallel technique for fabricating nanoscale pattern moulds by silicon etching followed by thermal oxidation. The mask pattern can be made by direct photolithography or photolithography followed by metal overetching for submicron- and nanoscale features, respectively. To successfully make nanoscale channels having a post-oxidation cross-sectional shape similar to that of the original channel, an oxidation mask to promote unidirectional (specifically horizontal) oxide growth is found to be essential. A silicon nitride or metal mask layer prevents vertical oxidation of the Si directly beneath it. Without this mask, rectangular channels become smaller but are V-shaped after oxidation. By controlling the silicon etch depth and oxidation time, moulds with high aspect ratio channels having widths ranging from 500 to 50 nm and smaller can be obtained. The nanomould, when passivated with a Teflon-like layer, can be used for first-generation replication using ultraviolet (UV) nanoembossing and second-generation replication in other materials, such as polydimethylsiloxane (PDMS). The PDMS stamp, which was subsequently coated with Au, was used for transfer printing of Au electrodes with a 600 nm gap which will find applications in plastics nanoelectronics

  12. ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

    International Nuclear Information System (INIS)

    Chen, Hung-Wei; He, Hsin-Min; Lee, Yi-Mu; Yang, Hsi-Wen

    2016-01-01

    ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O 2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O 2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h. (paper)

  13. Global freshwater thermal emissions from steam-electric power plants with once-through cooling systems

    International Nuclear Information System (INIS)

    Raptis, Catherine E.; Pfister, Stephan

    2016-01-01

    Large quantities of heat are rejected into freshwater bodies from power plants employing once-through cooling systems, often leading to temperature increases that disturb aquatic ecosystems. The objective of this work was to produce a high resolution global picture of power-related freshwater thermal emissions and to analyse the technological, geographical and chronological patterns behind them. The Rankine cycle was systematically solved for ∼2400 generating units with once-through cooling systems, distinguishing between simple and cogenerative cycles, giving the rejected heat as a direct output. With large unit sizes, low efficiencies, and high capacity factors, nuclear power plants reject 3.7 GW heat into freshwater on average, contrasting with 480 MW rejected from coal and gas power plants. Together, nuclear and coal-fuelled power plants from the 1970s and 1980s account for almost 50% of the rejected heat worldwide, offering motivation for their phasing out in the future. Globally, 56% of the emissions are rejected into rivers, pointing to potential areas of high thermal pollution, with the rest entering lakes and reservoirs. The outcome of this work can be used to further investigate the identified thermal emission hotspots, and to calculate regionalized water temperature increase and related impacts in environmental, energy-water nexus studies and beyond. - Highlights: • The thermodynamic cycles of ∼2400 power units with once-through cooling were solved. • Global freshwater heat emissions depend on technology, geography & chronology. • Half the global emissions come from nuclear and coal plants from the 70s & 80s. • Hotspots of freshwater thermal emissions were identified globally. • Global georeferenced emissions are available for use in water temperature models.

  14. Spitzer observations of the thermal emission from WASP-43b

    Energy Technology Data Exchange (ETDEWEB)

    Blecic, Jasmina; Harrington, Joseph; Stevenson, Kevin B.; Hardy, Ryan A.; Cubillos, Patricio E.; Hardin, Matthew; Bowman, Oliver; Nymeyer, Sarah [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Madhusudhan, Nikku [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Anderson, David R.; Hellier, Coel; Smith, Alexis M. S. [Astrophysics Group, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Cameron, Andrew Collier, E-mail: jasmina@physics.ucf.edu [SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS (United Kingdom)

    2014-02-01

    WASP-43b is one of the closest-orbiting hot Jupiters, with a semimajor axis of a = 0.01526 ± 0.00018 AU and a period of only 0.81 days. However, it orbits one of the coolest stars with a hot Jupiter (T {sub *} = 4520 ± 120 K), giving the planet a modest equilibrium temperature of T {sub eq} = 1440 ± 40 K, assuming zero Bond albedo and uniform planetary energy redistribution. The eclipse depths and brightness temperatures from our jointly fit model are 0.347% ± 0.013% and 1670 ± 23 K at 3.6 μm and 0.382% ± 0.015% and 1514 ± 25 K at 4.5 μm. The eclipse timings improved the estimate of the orbital period, P, by a factor of three (P = 0.81347436 ± 1.4 × 10{sup –7} days) and put an upper limit on the eccentricity (e=0.010{sub −0.007}{sup +0.010}). We use our Spitzer eclipse depths along with four previously reported ground-based photometric observations in the near-infrared to constrain the atmospheric properties of WASP-43b. The data rule out a strong thermal inversion in the dayside atmosphere of WASP-43b. Model atmospheres with no thermal inversions and fiducial oxygen-rich compositions are able to explain all the available data. However, a wide range of metallicities and C/O ratios can explain the data. The data suggest low day-night energy redistribution in the planet, consistent with previous studies, with a nominal upper limit of about 35% for the fraction of energy incident on the dayside that is redistributed to the nightside.

  15. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge

    International Nuclear Information System (INIS)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A.; Velazquez P, S.

    2008-01-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  16. Status of electron temperature and density measurement with beam emission spectroscopy on thermal helium at TEXTOR

    NARCIS (Netherlands)

    Schmitz, O.; Beigman, I. L.; Vainshtein, L. A.; Schweer, B.; Kantor, M.; Pospieszczyk, A.; Xu, Y.; Krychowiak, M.; Lehnen, M.; Samm, U.; Unterberg, B.

    2008-01-01

    Beam emission spectroscopy on thermal helium is used at the TEXTOR tokamak as a reliable method to obtain radial profiles of electron temperature T-e(r, t) and electron density ne(r, t). In this paper the experimental realization of this method at TEXTOR and the status of the atomic physics employed

  17. Self-scheduling and bidding strategies of thermal units with stochastic emission constraints

    International Nuclear Information System (INIS)

    Laia, R.; Pousinho, H.M.I.; Melíco, R.; Mendes, V.M.F.

    2015-01-01

    Highlights: • The management of thermal power plants is considered for different emission allowance levels. • The uncertainty on electricity price is considered by a set of scenarios. • A stochastic MILP approach allows devising the bidding strategies and hedging against price uncertainty and emission allowances. - Abstract: This paper is on the self-scheduling problem for a thermal power producer taking part in a pool-based electricity market as a price-taker, having bilateral contracts and emission-constrained. An approach based on stochastic mixed-integer linear programming approach is proposed for solving the self-scheduling problem. Uncertainty regarding electricity price is considered through a set of scenarios computed by simulation and scenario-reduction. Thermal units are modelled by variable costs, start-up costs and technical operating constraints, such as: forbidden operating zones, ramp up/down limits and minimum up/down time limits. A requirement on emission allowances to mitigate carbon footprint is modelled by a stochastic constraint. Supply functions for different emission allowance levels are accessed in order to establish the optimal bidding strategy. A case study is presented to illustrate the usefulness and the proficiency of the proposed approach in supporting biding strategies

  18. Transition Region Emission and the Energy Input to Thermal Plasma in Solar Flares

    Science.gov (United States)

    Holman, Gordon D.; Holman, Gordon D.; Dennis, Brian R.; Haga, Leah; Raymond, John C.; Panasyuk, Alexander

    2005-01-01

    Understanding the energetics of solar flares depends on obtaining reliable determinations of the energy input to flare plasma. X-ray observations of the thermal bremsstrahlung from hot flare plasma provide temperatures and emission measures which, along with estimates of the plasma volume, allow the energy content of this hot plasma to be computed. However, if thermal energy losses are significant or if significant energy goes directly into cooler plasma, this is only a lower limit on the total energy injected into thermal plasma during the flare. We use SOHO UVCS observations of O VI flare emission scattered by coronal O VI ions to deduce the flare emission at transition region temperatures between 100,000 K and 1 MK for the 2002 July 23 and other flares. We find that the radiated energy at these temperatures significantly increases the deduced energy input to the thermal plasma, but by an amount that is less than the uncertainty in the computed energies. Comparisons of computed thermal and nonthermal electron energies deduced from RHESSI, GOES, and UVCS are shown.

  19. HIGH-ENERGY NON-THERMAL AND THERMAL EMISSION FROM GRB 141207A DETECTED BY FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, Makoto [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo, 169-8555 (Japan); Asano, Katsuaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan); Ohno, Masanori [Department of Physical Sciences, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526 (Japan); Veres, Péter [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Axelsson, Magnus [KTH Royal Institute of Technology, Department of Physics, SE-106 91 Stockholm (Sweden); Bissaldi, Elisabetta [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy); Tachibana, Yutaro; Kawai, Nobuyuki, E-mail: m.arimoto@aoni.waseda.jp [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8551 (Japan)

    2016-12-20

    A bright long gamma-ray burst GRB 141207A was observed by the Fermi Gamma-ray Space Telescope and detected by both instruments onboard. The observations show that the spectrum in the prompt phase is not well described by the canonical empirical Band function alone, and that an additional power-law component is needed. In the early phase of the prompt emission, a modified blackbody with a hard low-energy photon index ( α  = +0.2 to +0.4) is detected, which suggests a photospheric origin. In a finely time-resolved analysis, the spectra are also well fitted by the modified blackbody combined with a power-law function. We discuss the physical parameters of the photosphere such as the bulk Lorentz factor of the relativistic flow and the radius. We also discuss the physical origin of the extra power-law component observed during the prompt phase in the context of different models such as leptonic and hadronic scenarios in the internal shock regime and synchrotron emission in the external forward shock. In the afterglow phase, the temporal and spectral behaviors of the temporally extended high-energy emission and the fading X-ray emission detected by the X-Ray Telescope on-board Swift are consistent with synchrotron emission in a radiative external forward shock.

  20. DETECTION OF THERMAL EMISSION FROM A SUPER-EARTH

    Energy Technology Data Exchange (ETDEWEB)

    Demory, Brice-Olivier; Seager, Sara; Benneke, Bjoern [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Gillon, Michaeel [Institut d' Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, Liege 1 (Belgium); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Jackson, Brian, E-mail: demory@mit.edu [Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Road NW, Washington, DC 20015 (United States)

    2012-06-01

    We report on the detection of infrared light from the super-Earth 55 Cnc e, based on four occultations obtained with Warm Spitzer at 4.5 {mu}m. Our data analysis consists of a two-part process. In a first step, we perform individual analyses of each data set and compare several baseline models to optimally account for the systematics affecting each light curve. We apply independent photometric correction techniques, including polynomial detrending and pixel mapping, that yield consistent results at the 1{sigma} level. In a second step, we perform a global Markov Chain Monte Carlo analysis, including all four data sets that yield an occultation depth of 131 {+-} 28 ppm, translating to a brightness temperature of 2360 {+-} 300 K in the IRAC 4.5 {mu}m channel. This occultation depth suggests a low Bond albedo coupled to an inefficient heat transport from the planetary day side to the night side, or else possibly that the 4.5 {mu}m observations probe atmospheric layers that are hotter than the maximum equilibrium temperature (i.e., a thermal inversion layer or a deep hot layer). The measured occultation phase and duration are consistent with a circular orbit and improves the 3{sigma} upper limit on 55 Cnc e's orbital eccentricity from 0.25 to 0.06.

  1. Non-thermal Hard X-Ray Emission from Coma and Several Abell Clusters

    International Nuclear Information System (INIS)

    Correa, C

    2004-01-01

    We report results of hard X-Ray observations of the clusters Coma, Abell 496, Abell754, Abell 1060, Abell 1367, Abell2256 and Abell3558 using RXTE data from the NASA HEASARC public archive. Specifically we searched for clusters with hard x-ray emission that can be fitted by a power law because this would indicate that the cluster is a source of non-thermal emission. We are assuming the emission mechanism proposed by Vahk Petrosian where the inter cluster space contains clouds of relativistic electrons that by themselves create a magnetic field and emit radio synchrotron radiation. These relativistic electrons Inverse-Compton scatter Microwave Background photons up to hard x-ray energies. The clusters that were found to be sources of non-thermal hard x-rays are Coma, Abell496, Abell754 and Abell 1060

  2. Numerical Investigation into CO Emission, O Depletion, and Thermal Decomposition in a Reacting Slab

    Directory of Open Access Journals (Sweden)

    O. D. Makinde

    2011-01-01

    Full Text Available The emission of carbon dioxide (CO2 is closely associated with oxygen (O2 depletion, and thermal decomposition in a reacting stockpile of combustible materials like fossil fuels (e.g., coal, oil, and natural gas. Moreover, it is understood that proper assessment of the emission levels provides a crucial reference point for other assessment tools like climate change indicators and mitigation strategies. In this paper, a nonlinear mathematical model for estimating the CO2 emission, O2 depletion, and thermal stability of a reacting slab is presented and tackled numerically using a semi-implicit finite-difference scheme. It is assumed that the slab surface is subjected to a symmetrical convective heat and mass exchange with the ambient. Both numerical and graphical results are presented and discussed quantitatively with respect to various parameters embedded in the problem.

  3. UV-visible, infrared and Raman spectroscopic and thermal studies of tungsten doped lead borate glasses and the effect of ionizing gamma irradiation

    International Nuclear Information System (INIS)

    El-Kheshen, Amany A.; El-Batal, Fatma H.; Marzouk, Samir Y.

    2008-01-01

    Ultraviolet-visible, infrared and Raman spectroscopy together with thermal properties were measured for undoped and WO 3 - doped (up to 10%) lead borate glasses. Also, the effect of gamma irradiation was followed by UV-visible measurements. The UV visible spectrum of the undoped glass reveals before irradiation intense ultraviolet bands due to the combined effects of trace iron impurities (Fe 3+ ) and Pb 2+ ions which remain unchanged with the addition of WO 3 . Infrared and Raman measurements show characteristic bands due to borate group and the possible sharing of lead-oxygen and tungsten-oxygen groups. The studied glasses show obvious resistance to gamma irradiation. The thermal and density data are correlated with the introduction of highly polarizable and heavy (W 6+ ) ions and to the change in structural arrangement with varying glass composition. (author)

  4. DUST ATTENUATION OF THE NEBULAR REGIONS OF z ∼ 2 STAR-FORMING GALAXIES: INSIGHT FROM UV, IR, AND EMISSION LINES

    Energy Technology Data Exchange (ETDEWEB)

    De Barros, S.; Reddy, N.; Shivaei, I., E-mail: stephane.debarros@oabo.inaf.it [Department of Physics and Astronomy, University of California, Riverside, CA 92507 (United States)

    2016-04-01

    We use a sample of 149 spectroscopically confirmed UV-selected galaxies at z ∼ 2 to investigate the relative dust attenuation of the stellar continuum and the nebular emission lines. For each galaxy in the sample, at least one rest-frame optical emission line (Hα/[N ii] λ6583 or [O iii] λ5007) measurement has been taken from the litterature, and 41 galaxies have additional Spitzer/MIPS 24 μm observations that are used to infer infrared luminosities. We use a spectral energy distribution (SED) fitting code that predicts nebular line strengths when fitting the stellar populations of galaxies in our sample, and we perform comparisons between the predictions of our models and the observed/derived physical quantities. We find that on average our code is able to reproduce all the physical quantities (e.g., UV β slopes, infrared luminosities, emission line fluxes), but we need to apply a higher dust correction to the nebular emission compared to the stellar emission for the largest star formation rate (SFR) (log SFR/M{sub ⊙} yr{sup −1} > 1.82, Salpeter initial mass function). We find a correlation between SFR and the difference in nebular and stellar color excesses, which could resolve the discrepant results regarding nebular dust correction at z ∼ 2 from previous studies.

  5. Is the aerosol emission detectable in the thermal infrared?

    Science.gov (United States)

    Hollweg, H.-D.; Bakan, S.; Taylor, J. P.

    2006-08-01

    The impact of aerosols on the thermal infrared radiation can be assessed by combining observations and radiative transfer calculations. Both have uncertainties, which are discussed in this paper. Observational uncertainties are obtained for two FTIR instruments operated side by side on the ground during the LACE 1998 field campaign. Radiative transfer uncertainties are assessed using a line-by-line model taking into account the uncertainties of the HITRAN 2004 spectroscopic database, uncertainties in the determination of the atmospheric profiles of water vapor and ozone, and differences in the treatment of the water vapor continuum absorption by the CKD 2.4.1 and MT_CKD 1.0 algorithms. The software package OPAC was used to describe the optical properties of aerosols for climate modeling. The corresponding radiative signature is a guideline to the assessment of the uncertainty ranges of observations and models. We found that the detection of aerosols depends strongly on the measurement accuracy of atmospheric profiles of water vapor and ozone and is easier for drier conditions. Within the atmospheric window, only the forcing of downward radiation at the surface by desert aerosol emerges clearly from the uncertainties of modeling and FTIR measurement. Urban and polluted continental aerosols are only partially detectable depending on the wave number and on the atmospheric water vapor amount. Simulations for the space-borne interferometer IASI show that only upward radiation above transported mineral dust aloft emerges out of the uncertainties. The detection of aerosols with weak radiative impact by FTIR instruments like ARIES and OASIS is made difficult by noise as demonstrated by the signal to noise ratio for clean continental aerosols. Altogether, the uncertainties found suggest that it is difficult to detect the optical depths of nonmineral and unpolluted aerosols.

  6. Thermal transformation of bioactive caffeic acid on fumed silica seen by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry and quantum chemical methods.

    Science.gov (United States)

    Kulik, Tetiana V; Lipkovska, Natalia O; Barvinchenko, Valentyna M; Palyanytsya, Borys B; Kazakova, Olga A; Dudik, Olesia O; Menyhárd, Alfréd; László, Krisztina

    2016-05-15

    Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Thermal, Mechanical and UV-Shielding Properties of Poly(Methyl Methacrylate/Cerium Dioxide Hybrid Systems Obtained by Melt Compounding

    Directory of Open Access Journals (Sweden)

    María A. Reyes-Acosta

    2015-09-01

    Full Text Available Thick and homogeneous hybrid film systems based on poly(methyl methacrylate (PMMA and CeO2 nanoparticles were synthesized using the melt compounding method to improve thermal stability, mechanical and UV-shielding properties, as well as to propose them for use in the multifunctional materials industry. The effect of the inorganic phase on these properties was assessed by using two different weight percentages of synthesized CeO2 nanoparticles (0.5 and 1.0 wt % with the sol–gel method and thermal treatment at different temperatures (120, 235, 400, 600 and 800 °C. Thereafter, the nanoceria powders were added to the polymer matrix by single screw extrusion. The absorption in the UV region was increased with the crystallite size of the CeO2 nanoparticles and the PMMA/CeO2 weight ratio. Due to the crystallinity of CeO2 nanoparticles, the thermal, mechanical and UV-shielding properties of the PMMA matrix were improved. The presence of CeO2 nanostructures exerts an influence on the mobility of PMMA chain segments, leading to a different glass transition temperature.

  8. Early Soft X-Ray to UV Emission from Double Neutron Star Mergers: Implications from the Long-term Observations of GW170817

    Science.gov (United States)

    Wang, Xiang-Yu; Huang, Zhi-Qiu

    2018-01-01

    Recent long-term radio follow-up observations of GW170817 reveal a simple power-law rising light curve, with a slope of {t}0.78, up to 93 days after the merger. The latest X-ray detection at 109 days is also consistent with such a temporal slope. Such a shallow rise behavior requires a mildly relativistic outflow with a steep velocity gradient profile, so that slower material with larger energy catches up with the decelerating ejecta and re-energizes it. It has been suggested that this mildly relativistic outflow may represent a cocoon of material. We suggest that the velocity gradient profile may form during the stage that the cocoon is breaking out of the merger ejecta, resulting from shock propagation down a density gradient. The cooling of the hot relativistic cocoon material immediately after it breaks out should have produced soft X-ray to UV radiation at tens of seconds to hours after the merger. The soft X-ray emission has a luminosity of {L}{{X}}∼ {10}45 {erg} {{{s}}}-1 over a period of tens of seconds for a merger event like GW170817. The UV emission shows a rise initially and peaks at about a few hours with a luminosity of {L}{UV}∼ {10}42 {erg} {{{s}}}-1. The soft X-ray transients could be detected by future wide-angle X-ray detectors, such as the Chinese mission Einstein Probe. This soft X-ray/UV emission would serve as one of the earliest electromagnetic counterparts of gravitation waves from double neutron star mergers and could provide the earliest localization of the sources.

  9. Thermal wind model for the broad emission line region of quasars

    International Nuclear Information System (INIS)

    Weymann, R.J.; Scott, J.S.; Schiano, A.V.R.; Christiansen, W.A.

    1982-01-01

    Arguments are summarized for supposing that the clouds giving rise to the broad emission lines of QSOs are confined by the pressure of an expanding thermal gas and that a flux of relativistic particles with luminosity comparable to the photon luminosity streams through this gas. The resulting heating and momentum deposition produces a transonic thermal wind whose dynamical properties are calculated in detail. This wind accelerates and confines the emission line clouds, thereby producing the broad emission line (BEL) profiles. In a companion paper, the properties of the wind at much larger distances (approx.kpc) than the BEL region are used to explain the production of the broad absorption lines (BAL) observed in some QSOs. The same set of wind parameters can account for the properties of both the BEL and BAL regions, and this unification in the physical description of the BEL and BAL regions is one of the most important advantages of this model. A characteristic size of approx.1 pc for the QSO emission line region is one consequence of the model. This characteristic size is shown to depend upon luminosity in such a way that the ionization parameter is roughly constant over a wide range of luminosities. An X-ray luminosity due to thermal bremsstrahlung of approx.1%--10% of the optical luminosity is another consequence of the model. The trajectories of clouds under the combined influence of ram pressure acceleration and radiative acceleration are calculated. From these trajectories emission line profiles are also calculated, as well as the wind and cloud parameters yielding profiles in fair agreement with observed profiles explored. Opacity in the wind due to electron scattering displaces the line cores of optically thin lines to the blue. This is roughly compensated for by the redward skewing of optically thick lines due to preferential emission of photons from the back side of the clouds.void rapid depletion due to Compton losses are discussed

  10. Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yunkang [Department of Mathematics and Physics, Nanjing Institute of technology, Nanjing, 211167 (China); Chen, Jing, E-mail: chenjingmoon@gmail.com [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Zichen, E-mail: zz241@ime.ac.cn [Integrated system for Laser applications Group, Institute of Microelectronics of Chinese Academy of Sciences, 100029, Beijing (China)

    2017-02-28

    Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

  11. Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

    International Nuclear Information System (INIS)

    Cui, Yunkang; Chen, Jing; Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong; Zhang, Zichen

    2017-01-01

    Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

  12. Optimization of thermochromic VO2-based structures with tunable thermal emissivity

    International Nuclear Information System (INIS)

    Li Voti, R.; Larciprete, M.C.; Leahu, G.L.; Bertolotti, M.; Sibilia, C.

    2013-01-01

    In this paper we design and simulate VO 2 /metal multilayers to obtain a large tunability of the thermal emissivity of IR filters in the typical MWIR window of many infrared cameras. The multilayer structure is optimized to realise a low-emissivity filter at high temperatures useful for military purposes. The values of tunability found for VO 2 /metal multilayers are larger than the value for a single thick layer of VO 2 . Innovative SiO 2 /VO 2 synthetic opals are also investigated to enhance the optical tunability by combining the properties of a 3D periodic structure and the specific optical properties of vanadium dioxide.

  13. Energy transfer and colour tunability in UV light induced Tm3+/Tb3+/Eu3+: ZnB glasses generating white light emission.

    Science.gov (United States)

    Naresh, V; Gupta, Kiran; Parthasaradhi Reddy, C; Ham, Byoung S

    2017-03-15

    A promising energy transfer (Tm 3+ →Tb 3+ →Eu 3+ ) approach is brought forward to generate white light emission under ultraviolet (UV) light excitation for solid state lightening. Tm 3+ /Tb 3+ /Eu 3+ ions are combinedly doped in zinc borate glass system in view of understanding energy transfer process resulting in white light emission. Zinc borate (host) glass displayed optical and luminescence properties due to formation of Zn(II) x -[O(-II)] y centres in the ZnB glass matrix. At 360nm (UV) excitation, triply doped Tm 3+ /Tb 3+ /Eu 3+ : ZnB glasses simultaneously shown their characteristic emission bands in blue (454nm: 1 D 2 → 3 F 4 ), green (547nm: 5 D 4 → 7 F 5 ) and red (616nm: 5 D 0 → 7 F 2 ) regions. In triple ions doped glasses, energy transfer dynamics is discussed in terms of Forster-Dexter theory, excitation & emission profiles, lifetime curves and from partial energy level diagram of three ions. The role of Tb 3+ in ET from Tm 3+ →Eu 3+ was discussed using branch model. From emission decay analysis, energy transfer probability (P) and efficiency (η) were evaluated. Colour tunability from blue to white on varying (Tb 3+ , Eu 3+ ) content is demonstrated from Commission Internationale de L'Eclairage (CIE) chromaticity coordinates. Based on chromaticity coordinates, other colour related parameters like correlated colour temperature (CCT) and colour purity are also computed for the studied glass samples. An appropriate blending of such combination of rare earth ions could show better suitability as potential candidates in achieving multi-colour and warm/cold white light emission for white LEDs application in the field of solid state lightening. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    Energy Technology Data Exchange (ETDEWEB)

    Sasao, M. (National Inst. for Fusion Science, Nagoya (Japan)); Adams, J.M. (AEA Industrial Technology, Harwell (United Kingdom)); Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking)

    1994-01-01

    Spatial profiles of the neutron emission from deuterium plasmas are routinely obtained at the Joint European Torus (JET) using the line-integrated signals measured with a multichannel instrument. It is shown that the manner in which these profiles relax following the termination of strong heating with neutral beam injection (NBI) permits the local thermal diffusivity ([chi][sub i]) to be obtained with an accuracy of about 20%. (author).

  15. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    International Nuclear Information System (INIS)

    Sasao, M.; Adams, J.M.; Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van

    1994-01-01

    Spatial profiles of the neutron emission from deuterium plasmas are routinely obtained at the Joint European Torus (JET) using the line-integrated signals measured with a multichannel instrument. It is shown that the manner in which these profiles relax following the termination of strong heating with neutral beam injection (NBI) permits the local thermal diffusivity (χ i ) to be obtained with an accuracy of about 20%. (author)

  16. How Often Do Thermally Excited 630.0 nm Emissions Occur in the Polar Ionosphere?

    Science.gov (United States)

    Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag A.; Johnsen, Magnar G.

    2018-01-01

    This paper studies thermally excited emissions in the polar ionosphere derived from European Incoherent Scatter Svalbard radar measurements from the years 2000-2015. The peak occurrence is found around magnetic noon, where the radar observations show cusp-like characteristics. The ionospheric, interplanetary magnetic field and solar wind conditions favor dayside magnetic reconnection as the dominant driving process. The thermal emissions occur 10 times more frequently on the dayside than on the nightside, with an average intensity of 1-5 kR. For typical electron densities in the polar ionosphere (2 × 1011 m-3), we find the peak occurrence rate to occur for extreme electron temperatures (>3000 K), which is consistent with assumptions in literature. However, for extreme electron densities (>5 × 1011 m-3), we can now report on a completely new population of thermal emissions that may occur at much lower electron temperatures (˜2300 K). The empirical atmospheric model (NRLMSISE-00) suggests that the latter population is associated with enhanced neutral atomic oxygen densities.

  17. Patterns in thermal emissions from the volcanoes of the Aleutian Islands

    Science.gov (United States)

    Blackett, M.; Webley, P. W.; Dehn, J.

    2012-12-01

    Using AVHRR data 1993-2011 and the Alaska Volcano Observatory's Okmok II Algorithm, the thermal emissions from all volcanoes in the Aleutian Islands were converted from temperature to power emission and examined for periodicity. The emissions were also summed to quantify the total energy released throughout the period. It was found that in the period April 1997 - January 2004 (37% of the period) the power emission from the volcanoes of the island arc declined sharply to constitute just 5.7% of the total power output for the period (138,311 MW), and this was attributable to just three volcanoes: Veniaminof (1.0%), Cleveland (1.5%) and Shishaldin (3.2%). This period of apparent reduced activity contrasts with the periods both before and after and is unrelated to the number of sensors in orbit at the time. What is also evident from the data set is that in terms of overall power emission over this period, the majority of emitted energy is largely attributable to those volcanoes which erupt with regularity (again, Veniaminof [29.7%], Cleveland [17%] and Shishaldin [11.4%]), as opposed to from the relatively few, large scale events (i.e. Reboubt [5.4%], Okmok [8.3%], Augustine [9.7%]; Pavlov [13.9%] being an exception). Sum power emission from volcanoes in the Aleutian Islands (1993-2011)

  18. Thermal field emission observation of single-crystal LaB6

    International Nuclear Information System (INIS)

    Nagata, H.; Harada, K.; Shimizu, R.

    1990-01-01

    TFE (thermal field emission) properties of LaB 6 left-angle 100 right-angle and left-angle 310 right-angle single crystals were investigated by emission pattern observation. It was found that field evaporation with the tip temperature held at ∼1500 degree C is very useful to get a clean pattern of fourfold symmetry. Each of four bright spots in the clean pattern was presumed to correspond to left-angle 310 right-angle emission. It is proposed, as the most appropriate operating condition, to use the left-angle 310 right-angle LaB 6 tip at a temperature ∼1000 degree C in vacuum of 10 -9 Torr region, promising a new TF emitter of high brightness and stability for practical use

  19. Legislative measures for suppressing emission of nitrogen oxides from thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.

    1987-11-01

    Reviews measures taken by some countries to control emission of nitrogen oxides from thermal power stations run on solid fuels, mazout and gas. Refers to maximum permissible concentrations of nitrogen oxides in USA (100 mg/m/sup 3/), Canada (460 mg/m/sup 3/), Japan (41-62 mg/m/sup 3/) and several European countries. Discusses legislative measures in FRG (Federal Regulations BImSchG), particularly Instruction No. 13 BImSchV concerning large boilers run on solid fuels or mazout (continuous monitoring of nitrogen oxide emission into atmosphere, equipping old boilers with means of reducing nitrogen oxide emission, reduction of acid rain). Gives maximum permissible concentrations of nitrogen oxides for new boilers agreed by various countries. 5 refs.

  20. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    International Nuclear Information System (INIS)

    Sasao, M.; Adam, J.M.; Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van

    1992-01-01

    Spatial profiles of neutron emission are routinely obtained at the Joint European Torus (JET) from line-integrated emissivities measured with a multi-channel instrument. It is shown that the manner in which the emission profiles relax following termination of strong heating with Neutral Beam Injection (NBI) permits the local thermal diffusivity (χ i ) to be obtained with an accuracy of about 20%. The radial profiles of χ i for small minor radius (r/a 2 /s for H-mode plasmas with plasma current I p = 3.1 MA and toroidal field B T = 2.3T. The experimental value of χ i is smallest for Z eff = 2.2 and increases weakly with increasing Z eff . The experimental results disagree by two orders of magnitude with predictions from an ion temperature gradient driven turbulence model. (author) 6 refs., 3 figs

  1. Net emission coefficient for CO–H2 thermal plasmas with the consideration of molecular systems

    International Nuclear Information System (INIS)

    Billoux, T.; Cressault, Y.; Gleizes, A.

    2015-01-01

    This paper deals with the calculation of net emission coefficients (NECs) for CO–H 2 thermal plasmas. This task required the elaboration of a complete spectroscopic database including atoms and molecules formed by carbon, oxygen and hydrogen elements. We have used a systematic line by line method to calculate all the main radiative contributions which are the atomic and molecular continua, the atomic lines and the molecular (diatomic and polyatomic) lines. The main diatomic electronic systems for CO–H 2 plasmas and the triatomic molecular bands were considered. We present some variations of the net emission coefficient versus temperature, for various pressures and for two relative proportions of the components. The role of the diatomic molecules is important at temperatures lower than 5000 K whereas the net emission coefficient presents an unusual peak at temperature around 1000 K, due to the presence of the CO 2 molecule presenting a strong infrared radiation. Finally, the results show that the NEC slightly depends on the relative proportion of CO and H 2 . - highlights: • We calculate radiative losses from CO–H 2 thermal plasmas. • We use the up-to-date atomic and molecular databases. • The influence of CO 2 molecule is very important at low temperature. • The relative maximum of the net emission coefficient at low temperature is unusual

  2. CHARACTERIZATION OF EMISSIONS OF THERMALLY MODIFIED WOOD AND THEIR REDUCTION BY CHEMICAL TREATMENT

    Directory of Open Access Journals (Sweden)

    Jana Peters

    2008-05-01

    Full Text Available Thermal treatment is a suitable method for improving the quality of wood types like spruce, beech or poplar, and thus to open up new fields of application that used to be limited to tropical woods or woods treated with timber preservatives. These thermally treated woods are characterized by a typical odor caused by degradation products of miscellaneous wood components. The characterization and removal of those odorous substances were investigated using chromatographic and spectroscopic methods. Headspace gas chromatography (GC in combination with solid-phase microextraction (SPME was used for a qualitative analysis of volatile wood emissions, and the detectable volatiles were compared before and after solvent extraction. Wood solvent extractives were investigated by means of gas chromatography/mass spectrometry and then evaluated in terms of changes in composition caused by the thermal treatment process.

  3. Application of UV/H2O2 system to treatment of wastewater arising from thermal treatment of oil-water emulsions

    Directory of Open Access Journals (Sweden)

    Ivanildo Hespanhol

    2009-12-01

    Full Text Available In this work it is presented the results of bench scale tests using Advanced Oxidation Process (AOP in a UV/H2O2 system, for the treatment of an industrial effluent with a high concentration of dissolved organic matter, resulted from thermal treatment of oil-water emulsions. Treatability tests were carried out in a batch photochemical system with recycle, and the raw effluent was characterized by the analysis of pH, turbidity, color, COD and TOC. Results from these assays shown that UV/H2O2 process is technically feasible resulting in TOC removal above 90%. However, for one log TOC removal from this effluent the energy required was about 455.5 kw.h.m-3, for an alpha relation of 10 mg H2O2/mg COT, resulting in a higher operational cost, considering the evaluated conditions.

  4. Thermal emission before earthquakes by analyzing satellite infra-red data

    Science.gov (United States)

    Ouzounov, D.; Taylor, P.; Bryant, N.; Pulinets, S.; Freund, F.

    2004-05-01

    Satellite thermal imaging data indicate long-lived thermal anomaly fields associated with large linear structures and fault systems in the Earth's crust but also with short-lived anomalies prior to major earthquakes. Positive anomalous land surface temperature excursions of the order of 3-4oC have been observed from NOAA/AVHRR, GOES/METEOSAT and EOS Terra/Aqua satellites prior to some major earthquake around the world. The rapid time-dependent evolution of the "thermal anomaly" suggests that is changing mid-IR emissivity from the earth. These short-lived "thermal anomalies", however, are very transient therefore there origin has yet to be determined. Their areal extent and temporal evolution may be dependent on geology, tectonic, focal mechanism, meteorological conditions and other factors.This work addresses the relationship between tectonic stress, electro-chemical and thermodynamic processes in the atmosphere and increasing mid-IR flux as part of a larger family of electromagnetic (EM) phenomena related to seismic activity.We still need to understand better the link between seismo-mechanical processes in the crust, on the surface, and at the earth-atmospheric interface that trigger thermal anomalies. This work serves as an introduction to our effort to find an answer to this question. We will present examples from the strong earthquakes that have occurred in the Americas during 2003/2004 and the techniques used to record the thermal emission mid-IR anomalies, geomagnetic and ionospheric variations that appear to associated with impending earthquake activity.

  5. The EVE plus RHESSI DEM for Solar Flares, and Implications for Residual Non-Thermal X-Ray Emission

    Science.gov (United States)

    McTiernan, James; Caspi, Amir; Warren, Harry

    2016-05-01

    Solar flare spectra are typically dominated by thermal emission in the soft X-ray energy range. The low energy extent of non-thermal emission can only be loosely quantified using currently available X-ray data. To address this issue, we combine observations from the EUV Variability Experiment (EVE) on-board the Solar Dynamics Observatory (SDO) with X-ray data from the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI) to calculate the Differential Emission Measure (DEM) for solar flares. This improvement over the isothermal approximation helps to resolve the ambiguity in the range where the thermal and non-thermal components may have similar photon fluxes. This "crossover" range can extend up to 30 keV.Previous work (Caspi et.al. 2014ApJ...788L..31C) concentrated on obtaining DEM models that fit both instruments' observations well. For this current project we are interested in breaks and cutoffs in the "residual" non-thermal spectrum; i.e., the RHESSI spectrum that is left over after the DEM has accounted for the bulk of the soft X-ray emission. As in our earlier work, thermal emission is modeled using a DEM that is parametrized as multiple gaussians in temperature. Non-thermal emission is modeled as a photon spectrum obtained using a thin-target emission model ('thin2' from the SolarSoft Xray IDL package). Spectra for both instruments are fit simultaneously in a self-consistent manner.For this study, we have examined the DEM and non-thermal resuidual emission for a sample of relatively large (GOES M class and above) solar flares observed from 2011 to 2014. The results for the DEM and non-thermal parameters found using the combined EVE-RHESSI data are compared with those found using only RHESSI data.

  6. VIRTIS on Venus Express thermal emission spectra near 1μm

    Science.gov (United States)

    Mueller, Nils; Tsang, Constantine; Helbert, Joern; Smrekar, Suzanne; Piccioni, Giuseppe; Drossart, Pierre

    2016-10-01

    Thermal emission from the surface of Venus is observable through narrow spectral windows close to 1μm. Surface temperature is strongly constrained by surface elevation, due to the thick and dense atmosphere. The data from Visible and InfraRed Thermal Imaging Spectrometer VIRTIS on Venus Express together with altimetry constrain surface emissivity. In VIRTIS observations at 1.02μm, strongly deformed highland plateaus (tesserae) appear to have a lower emissivity consistent with continental crust, an interpretation that implies existence of an early ocean. Comparison between the Magellan stereo digital elevation model (DEM) and altimetry shows that the altimetry height error in rough tesserae greatly exceeds the formal error. In the one tesserae outlier covered by altimetry, DEM, and VIRTIS, the height error could account for the observed emissivity variation. The radiances observed at 1.10 and 1.18μm have a different response to topography, mostly due to spectrally varying absorption in the overlying atmospheric column. Thus if the tesserae have the same emissivity as volcanic plains, its spectrum should be the same as that of plains of the correct surface elevation. In order to investigate this statistically, we create a database of all long exposure duration VIRTIS spectra in the range of 1 - 1.4μm. The spectra are corrected for the ubiquitous straylight from the dayside, based on analysis of spectra showing deep space. Because the 1.10 and 1.18μm peaks are narrow compared to the variation of instrument spectral registration, we fit each spectrum with a synthetic spectrum from an atmospheric radiative transfer model, using wavelength offset and bandwidths as parameters in addition to atmospheric variables. This dataset of ~28 million thermal emission spectra spans a wide range of southern latitudes and night local times, and thus may be useful for studies beyond the question of surface emissivity. A portion of this research was conducted at the Jet Propulsion

  7. Thermal behavior of J-aggregates in a Langmuir-Blodgett film of pure merocyanine dye investigated by UV-visible and IR absorption spectroscopy.

    Science.gov (United States)

    Hirano, Yoshiaki; Tateno, Shinsuke; Maio, Ari; Ozaki, Yukihiro

    2009-03-05

    We have characterized the structure of J-aggregate in a Langmuir-Blodgett film of pure merocyanine dye (MS18) fabricated under an aqueous subphase containing a cadmium ion (Cd2+) and have investigated its thermal behavior by UV-visible and IR absorption spectroscopy in the range from 25 to 250 degrees C with a continuous scan. The results of both UV-visible and IR absorption spectra indicate that temperature-dependent changes in the MS18 aggregation state in the pure MS18 system are closely and mildly linked with the MS18 intramolecular charge transfer and the behavior of the packing, orientation, conformation, and thermal mobility of MS18 hydrocarbon chain, respectively. The J-aggregate in the pure MS18 system dissociates from 25 to 150 degrees C, and the dissociation temperature at 150 degrees C is higher by 50 degrees C than that in the previous MS18- arachidic acid (C20) binary system. The lower dissociation temperature in the binary system originates from the fact that temperature-dependent structural disorder of cadmium arachidate (CdC20), being phase-separated from MS18, has an influence on the dissociation of J-aggregate. From 160 to 180 degrees C, thermally induced blue-shifted bands, caused by the oligomeric MS18 aggregation, appear at around 520 nm in the pure MS18 system by contraries, regardless of the lack of driving force by the melting phenomenon of CdC20. The temperature at which the 520 nm bands occur is in good agreement with the melting point (160 degrees C) of hydrocarbon chain in MS18 with Cd2+, whereas its chromophore part is clearly observed to melt near 205 degrees C by UV-visible spectra. Therefore, it is suggested that the driving force that induces the 520 nm band in the pure MS18 system arises from the partial melting of hydrocarbon chain in MS18 with Cd2+.

  8. Effect of adjustable molecular chain structure and pure silica zeolite nanoparticles on thermal, mechanical, dielectric, UV-shielding and hydrophobic properties of fluorinated copolyimide composites

    Science.gov (United States)

    Li, Qing; Liao, Guangfu; Zhang, Shulai; Pang, Long; Tong, Hao; Zhao, Wenzhe; Xu, Zushun

    2018-01-01

    A series of polyimide (PI) films, polyimide/pure silica zeolite nanoparticles (PSZN) blend films and polyimide/amine-functionalized pure silica zeolite nanoparticles (APSZN) composite films were successfully prepared by random copolycondensation. Thereinto, PSZN were synthesized by hydrothermal method. The polyimides were derived from 4,4‧-diaminodiphenyl ether (ODA), and three adjustable molar ratios (3:1, 1:1, 1:3) of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride (BPADA) and 4,4‧-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The effects of PSZN, APSZN and different chain structure on PI films were specifically evaluated in terms of morphology, thermal, mechanical, dielectric and UV-shielding properties, etc. Comparison was given among pure PI flims, PI/PSZN blend films and PI/APSZN composite flims. The results showed that the thermal and mechanical properties of PI films were drastically impaired after adding PSZN. On the contrary, the strength, toughness and thermal stability were improved after adding APSZN. Moreover, the dielectric constants of the PI/APSZN composite flims were lowered but UV-shielding properties were enhanced. Interestingly, we found that the greatest effects were obtained through introducing APSZN in PI derived by the 1:1 ratio of BPADA:6FDA. The corresponding PI/APSZN composite flim exhibited the most reinforced and toughened properties, the largest decrement of dielectric constant and the best UV-shielding efficiency, which made the composite flim be used as ultraviolet shielding material in outer space filled with high temperature and intensive ultraviolet light. Meanwhile, this work also provided a facile way to synthesize composite materials with adjustable performance.

  9. Local Group dSph radio survey with ATCA - II. Non-thermal diffuse emission

    Science.gov (United States)

    Regis, Marco; Richter, Laura; Colafrancesco, Sergio; Profumo, Stefano; de Blok, W. J. G.; Massardi, Marcella

    2015-04-01

    Our closest neighbours, the Local Group dwarf spheroidal (dSph) galaxies, are extremely quiescent and dim objects, where thermal and non-thermal diffuse emissions lack, so far, of detection. In order to possibly study the dSph interstellar medium, deep observations are required. They could reveal non-thermal emissions associated with the very low level of star formation, or to particle dark matter annihilating or decaying in the dSph halo. In this work, we employ radio observations of six dSphs, conducted with the Australia Telescope Compact Array in the frequency band 1.1-3.1 GHz, to test the presence of a diffuse component over typical scales of few arcmin and at an rms sensitivity below 0.05 mJy beam-1. We observed the dSph fields with both a compact array and long baselines. Short spacings led to a synthesized beam of about 1 arcmin and were used for the extended emission search. The high-resolution data mapped background sources, which in turn were subtracted in the short-baseline maps, to reduce their confusion limit. We found no significant detection of a diffuse radio continuum component. After a detailed discussion on the modelling of the cosmic ray (CR) electron distribution and on the dSph magnetic properties, we present bounds on several physical quantities related to the dSphs, such that the total radio flux, the angular shape of the radio emissivity, the equipartition magnetic field, and the injection and equilibrium distributions of CR electrons. Finally, we discuss the connection to far-infrared and X-ray observations.

  10. The Spatial Distribution of Thermal Emission from Baghdad Sulcus, Enceladus, at 100 meter Scales

    Science.gov (United States)

    Spencer, John R.; Gorius, N. J. P.; Howett, C. J. A.; Jennings, D. E.; Albright, S. A.

    2012-10-01

    The Cassini Composite Infrared Spectrometer (CIRS) has been observing endogenic thermal emission from the south pole of Enceladus since 2005. Best spatial resolution from conventional scans is about 1km, usually from distances > 2000 km. When Cassini is closer to Enceladus, the spacecraft cannot rotate fast enough to track the surface, and the 5 seconds required to obtain a CIRS spectrum produces many kilometers of smear. However, higher-resolution mapping can be done from much closer range by exploiting the 20 msec sampling of the CIRS raw interferograms. On April 14th 2012, Cassini made a gravity pass of Enceladus at a range of 74 km. Spacecraft orientation was inertially fixed, and chosen so that the active tiger stripe Baghdad Sulcus passed through the CIRS and VIMS fields of view during the flyby. In the 7 to 17 µm region, CIRS uses linear arrays of ten detectors with IFOV of 0.29 mrad, which were oriented roughly perpendicular to the groundtrack and operated in pairs, giving five cross-track spatial resolution elements, each 43 meters wide. Along-track spatial resolution, defined by the 20 msec interferogram sampling time and the flyby speed of 7.5 km/sec, was 150 meters. At longer wavelengths, CIRS obtained a single-detector scan with a spatial resolution of 300 meters. The brief passage of the intense tiger stripe thermal emission through the field of view produced complex spikes in the CIRS interferograms. Though spectra cannot be reconstructed, we can use knowledge of the interferogram temporal response to reconstruct the time history of the incoming radiation and thus its spatial distribution. The resulting image will map tiger stripe thermal emission along a small part of Baghdad Sulcus at about ten times the spatial resolution of the best previous Cassini thermal images.

  11. Thermal runaway of metal nano-tips during intense electron emission

    Science.gov (United States)

    Kyritsakis, A.; Veske, M.; Eimre, K.; Zadin, V.; Djurabekova, F.

    2018-06-01

    When an electron emitting tip is subjected to very high electric fields, plasma forms even under ultra high vacuum conditions. This phenomenon, known as vacuum arc, causes catastrophic surface modifications and constitutes a major limiting factor not only for modern electron sources, but also for many large-scale applications such as particle accelerators, fusion reactors etc. Although vacuum arcs have been studied thoroughly, the physical mechanisms that lead from intense electron emission to plasma ignition are still unclear. In this article, we give insights to the atomic scale processes taking place in metal nanotips under intense field emission conditions. We use multi-scale atomistic simulations that concurrently include field-induced forces, electron emission with finite-size and space-charge effects, Nottingham and Joule heating. We find that when a sufficiently high electric field is applied to the tip, the emission-generated heat partially melts it and the field-induced force elongates and sharpens it. This initiates a positive feedback thermal runaway process, which eventually causes evaporation of large fractions of the tip. The reported mechanism can explain the origin of neutral atoms necessary to initiate plasma, a missing key process required to explain the ignition of a vacuum arc. Our simulations provide a quantitative description of in the conditions leading to runaway, which shall be valuable for both field emission applications and vacuum arc studies.

  12. MODELING THERMAL DUST EMISSION WITH TWO COMPONENTS: APPLICATION TO THE PLANCK HIGH FREQUENCY INSTRUMENT MAPS

    International Nuclear Information System (INIS)

    Meisner, Aaron M.; Finkbeiner, Douglas P.

    2015-01-01

    We apply the Finkbeiner et al. two-component thermal dust emission model to the Planck High Frequency Instrument maps. This parameterization of the far-infrared dust spectrum as the sum of two modified blackbodies (MBBs) serves as an important alternative to the commonly adopted single-MBB dust emission model. Analyzing the joint Planck/DIRBE dust spectrum, we show that two-component models provide a better fit to the 100-3000 GHz emission than do single-MBB models, though by a lesser margin than found by Finkbeiner et al. based on FIRAS and DIRBE. We also derive full-sky 6.'1 resolution maps of dust optical depth and temperature by fitting the two-component model to Planck 217-857 GHz along with DIRBE/IRAS 100 μm data. Because our two-component model matches the dust spectrum near its peak, accounts for the spectrum's flattening at millimeter wavelengths, and specifies dust temperature at 6.'1 FWHM, our model provides reliable, high-resolution thermal dust emission foreground predictions from 100 to 3000 GHz. We find that, in diffuse sky regions, our two-component 100-217 GHz predictions are on average accurate to within 2.2%, while extrapolating the Planck Collaboration et al. single-MBB model systematically underpredicts emission by 18.8% at 100 GHz, 12.6% at 143 GHz, and 7.9% at 217 GHz. We calibrate our two-component optical depth to reddening, and compare with reddening estimates based on stellar spectra. We find the dominant systematic problems in our temperature/reddening maps to be zodiacal light on large angular scales and the cosmic infrared background anisotropy on small angular scales

  13. On the multiphoton emission during U.V. and X-ray absorption by atoms in intense laser fields

    International Nuclear Information System (INIS)

    Miranda, L.C.M.

    1981-09-01

    A discussion of the u.v. and x-ray absorption cross section by a hydrogen atom in the presence of an intense i.r. laser field is presented, taking into account the influence of laser field on the electronic states. (Author) [pt

  14. The effect of radiation-thermal treatment on the physicochemical properties of the Ni-Mo/Al2O3 hydrotreatment catalyst. II. UV-Vis diffuse reflectance spectra of surface compounds after irradiation

    International Nuclear Information System (INIS)

    Solovetskii, Yu.I.; Miroshinichenko, I.I.; Lunin, V.V.

    1993-01-01

    Radiation-thermal damage of the surface and the active metal phases of hydrodesulfurization Ni-Mo/Al 2 O 3 catalysts by a fast electron beam of up to 2.0 MeV energy was studied. UV-Vis diffuse reflectance spectra of the industrial and model coked systems after radiation-thermal treatment were measured. 14 refs., 2 figs

  15. Thermal effects on light emission in Yb3+ -sensitized rare-earth doped optical glasses

    International Nuclear Information System (INIS)

    Gouveia, E.A.; Araujo, M.T. de; Gouveia-Neto, A.S.

    2001-01-01

    The temperature effect upon infrared-to-visible frequency upconversion fluorescence emission in off-resonance infrared excited Yb 3+ -sensitized rare-earth doped optical glasses is theoretically and experimentally investigated. We have examined samples of Er3+/Yb 3+ -codoped Ga 2 S 3 :La 2 O 3 chalcogenide glasses and germanosilicate optical fibers, and Ga2O3:La 2 O 3 chalcogenide and fluoroindate glasses codoped with Pr 3+ /Yb 3+ , excited off-resonance at 1.064μm. The experimental results revealed thermal induced enhancement in the visible upconversion emission intensity as the samples temperatures were increased within the range of 20 deg C to 260 deg C. The fluorescence emission enhancement is attributed to the temperature dependent multiphonon-assisted anti-Stokes excitation process of the ytterbium-sensitizer. A theoretical approach that takes into account a sensitizer temperature dependent effective absorption cross section, which depends upon the phonon occupation number in the host matrices, has proven to agree very well with the experimental data. As beneficial applications of the thermal enhancement, a temperature tunable amplifier and a fiber laser with improved power performance are presented. (author)

  16. Thermal Cracking in Westerly Granite Monitored Using Direct Wave Velocity, Coda Wave Interferometry, and Acoustic Emissions

    Science.gov (United States)

    Griffiths, L.; Lengliné, O.; Heap, M. J.; Baud, P.; Schmittbuhl, J.

    2018-03-01

    To monitor both the permanent (thermal microcracking) and the nonpermanent (thermo-elastic) effects of temperature on Westerly Granite, we combine acoustic emission monitoring and ultrasonic velocity measurements at ambient pressure during three heating and cooling cycles to a maximum temperature of 450°C. For the velocity measurements we use both P wave direct traveltime and coda wave interferometry techniques, the latter being more sensitive to changes in S wave velocity. During the first cycle, we observe a high acoustic emission rate and large—and mostly permanent—apparent reductions in velocity with temperature (P wave velocity is reduced by 50% of the initial value at 450°C, and 40% upon cooling). Our measurements are indicative of extensive thermal microcracking during the first cycle, predominantly during the heating phase. During the second cycle we observe further—but reduced—microcracking, and less still during the third cycle, where the apparent decrease in velocity with temperature is near reversible (at 450°C, the P wave velocity is decreased by roughly 10% of the initial velocity). Our results, relevant for thermally dynamic environments such as geothermal reservoirs, highlight the value of performing measurements of rock properties under in situ temperature conditions.

  17. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    Energy Technology Data Exchange (ETDEWEB)

    Zebbar, N., E-mail: nacbar2003@yahoo.fr [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Chabane, L. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Gabouze, N. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Kechouane, M. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Trari, M. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, El-Alia, Algiers (Algeria); Aida, M.S. [LCM et Interface, Faculty of Sciences, University of Constantine, 25000 (Algeria); Belhousse, S. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Hadj Larbi, F. [MEMS & Sensors, Division Microélectronique et Nanotechnologie, Centre de Développement des Technologies Avancées (CDTA), BP 17, Baba Hassen, Algiers (Algeria)

    2016-04-30

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10{sup −2} to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  18. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    International Nuclear Information System (INIS)

    Zebbar, N.; Chabane, L.; Gabouze, N.; Kechouane, M.; Trari, M.; Aida, M.S.; Belhousse, S.; Hadj Larbi, F.

    2016-01-01

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10 −2 to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  19. Near-UV sensitized 1.06 μm emission of Nd{sup 3+} ions via monovalent copper in phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, José A., E-mail: jose.jimenez@unf.edu [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Sendova, Mariana [Optical Spectroscopy & Nano-Materials Lab, New College of Florida, Sarasota, FL 34243 (United States)

    2015-07-15

    Monovalent copper ions effectively incorporated in Nd-containing phosphate glass by a single-step melt-quench method have been established as near-ultraviolet (UV) sensitizers of Nd{sup 3+} ions, resulting in a remarkable {sup 4}F{sub 3/2} → {sup 4}I{sub 11/2} emission at 1.06 μm. The spectroscopic data indicates an efficient energy conversion process. The Cu{sup +} ions first absorb photons broadly around 360 nm, and subsequently transfer the energy from the Stokes-shifted emitting states to resonant Nd{sup 3+} energy levels in the visible. Ultimately, the Nd{sup 3+} electronic excited states decay and the upper lasing state {sup 4}F{sub 3/2} is populated, leading to the enhanced emission at 1.06 μm. The characteristic features of the Cu{sup +} visible emission spectra and the reduced lifetime of the corresponding Cu{sup +} donor states indicate an efficient non-radiative transfer. The Cu{sup +}/Nd{sup 3+} co-doped phosphate glass appears suitable as solid-state laser material with enhanced pump range in the near-UV part of the spectrum and for solar spectral conversion in photovoltaic cells. - Graphical abstract: Display Omitted - Highlights: • Monovalent copper ions effectively stabilized in Nd{sup 3+}-containing phosphate glass. • Enhanced Nd{sup 3+} near-infrared emission observed upon the Cu{sup +} ions incorporation. • Cu{sup +} → Nd{sup 3+} non-radiative energy transfer efficiencies and likely energy transfer pathways evaluated. • Potential for solid-state lasers and solar spectral conversion suggested.

  20. A Global Outlook to the Carbon Dioxide Emissions in the World and Emission Factors of the Thermal Power Plants in Turkey

    International Nuclear Information System (INIS)

    Atimtay, Aysel T.

    2003-01-01

    World primary energy demand increases with increases in population and economic development. Within the last 25 yr, the total energy consumption has almost doubled. For the purpose of meeting this demand, fossil energy sources are used and various pollutants are generated. CO 2 is also one of these gases, which cannot be removed like other pollutants, and it causes greenhouse effect and climate change. Reducing the CO 2 emission is very important because of the environmental concerns and regulations, especially the Kyoto Protocol. This paper reviews the estimated world carbon emissions, Turkey's situation in electrical energy production, emission amounts estimated until the year 2020 and emission factors for dust, SO 2 , NO x and CO 2 . The estimated results show that CO 2 emissions from thermal power plants in Turkey will make about 0.66 % of the global CO 2 emissions in 2020

  1. Measuring the spectral emissivity of thermal protection materials during atmospheric reentry simulation

    Science.gov (United States)

    Marble, Elizabeth

    1996-01-01

    Hypersonic spacecraft reentering the earth's atmosphere encounter extreme heat due to atmospheric friction. Thermal Protection System (TPS) materials shield the craft from this searing heat, which can reach temperatures of 2900 F. Various thermophysical and optical properties of TPS materials are tested at the Johnson Space Center Atmospheric Reentry Materials and Structures Evaluation Facility, which has the capability to simulate critical environmental conditions associated with entry into the earth's atmosphere. Emissivity is an optical property that determines how well a material will reradiate incident heat back into the atmosphere upon reentry, thus protecting the spacecraft from the intense frictional heat. This report describes a method of measuring TPS emissivities using the SR5000 Scanning Spectroradiometer, and includes system characteristics, sample data, and operational procedures developed for arc-jet applications.

  2. Impact of coal-fired thermal power plant emissions on surrounding vegetative environment: a case study

    International Nuclear Information System (INIS)

    Soni, D.K.; Senger, C.B.S.

    1993-01-01

    Vegetative system around the thermal power plants are exposed to perpetual emissions of particulates as well as gaseous pollutants in various forms and nature. These emissions evidently are reflected in plant responses. In order to assess the response of natural flora of this region, 2 plant species, that is Mangifera indica and Holarrhina artidysentrica and certain pollution sensitive parameter, such as leaf area, pH of wash water of foliage and sugar content of the leaves were identified for this study. It was observed that the pH of wash solution of leaves was close to neutral in upstream locations and in polluted zone pH was acidic. Leaf area was higher in least polluted zone and lower in more polluted locations. Dust deposition on leaves was observed be lower in upstream locations and higher in influenced areas. Sugar variations in leaves showed negative impact in affected areas. (author). 9 refs., 5 tabs

  3. Thermal dependence of free exciton emission in ultraviolet cathodoluminescence of colloidal ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Bui, Hong Van; Pham, Van Ben [Faculty of Physics, VNU-Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Le, Si Dang [Institut Néel, CNRS, 25 rue des Martyrs, BP 166, F-38042 Grenoble Cedex 9 (France); Hoang, Nam Nhat, E-mail: namnhat@gmail.com [Faculty of Engineering Physics and Nanotechnology, VNU-University of Engineering and Technology, 144 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)

    2016-10-15

    Cathodoluminescence properties of the colloidal ZnS nanopowders synthesized by using hydrothermal process, a large scale production method, are reported. The cathodoluminescence spectra were obtained for temperature from 5 to 300 K, where an intensive free exciton originated 326 nm emission was observed. This band did not split under the increase of excitation beam current density and prevailed even at room temperature. The weaker emissions appeared at 331, 333, 337 and 343 nm which were related to excitons bound to neutral acceptor (A{sup o}, X), transition from conduction band to acceptor levels (e, A) and their corresponding (e, A)−1LO, (e, A)−2LO phonon replicas. With increasing temperature the free exciton band shifted towards lower energy and its intensity decreased at 36.5 meV thermal quenching threshold. The dependence of band gap on temperature was also determined.

  4. The influence of thermal regime on gasoline direct injection engine performance and emissions

    Science.gov (United States)

    Leahu, C. I.; Tarulescu, S.

    2016-08-01

    This paper presents the experimental research regarding to the effects of a low thermal regime on fuel consumption and pollutant emissions from a gasoline direct injection (GDI) engine. During the experimental researches, the temperature of the coolant and oil used by the engine were modified 4 times (55, 65, 75 and 85 oC), monitoring the effects over the fuel consumption and emissions (CO2, CO and NOx). The variations in temperature of the coolant and oil have been achieved through AVL coolant and oil conditioning unit, integrated in the test bed. The obtained experimental results reveals the poor quality of exhaust gases and increases of fuel consumption for the gasoline direct injection engines that runs outside the optimal ranges for coolant and oil temperatures.

  5. Reducing energy consumption and CO{sub 2} emissions in thermally coupled azeotropic distillation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L.Y.; Chang, X.W.; Zhang, Y.M.; Li, J.; Li, Q.S. [Department of Chemical Engineering, China University of Petroleum, Qingdao, Shandong Province (China)

    2010-03-15

    The design and optimization procedures of a heterogeneous thermally coupled azeotropic distillation sequence with a side stripper (TCADS-SS) for the purification of isopropanol has been investigated. The proposed procedures can detect the optimal values of the design variables and thereby guarantee the minimum energy consumption, which is related to the minimum CO{sub 2} emissions and the lowest total annual cost (TAC). The procedures are applied to the study of the separation of azeotropic mixtures using the two distillation sequences. In the TCADS-SS, the top end of the side stripper has both liquid and vapor exchange with the main column, which eliminates a condenser in contrast with the conventional heterogeneous azeotropic distillation sequence (CHADS). The results show that not only reductions in energy consumption and CO{sub 2} emissions but also higher thermodynamic efficiency can be obtained for the TCADS-SS. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Emission factors and thermal efficiencies of cooking biofuels from five countries

    International Nuclear Information System (INIS)

    Gupta, S.; Saksena, S.; Shankar, V.R.; Joshi, V.

    1998-01-01

    The aim of the study was to compare the environmental and thermal performance of cooking biofuels from five countries. The standard water boiling test was used to determine thermal parameters. The fuels were burnt in a metal stove in a test chamber in accordance with standard protocol. Low-flow air samplers were used for particulate matter measurements, both TSP and RSP. Later, benzo(a)pyrene was determined using the high performance liquid chromatography (HPLC) technique after extraction from particulate samples in benzene. CO was measured using an electronic datalogger and HCHO using a passive sampler. The ventilation conditions during the experiments were manipulated by using different combinations of doors, windows and fans to ensure minimum stratification of pollutants in the chamber. The indirect method of deriving emission factors was used. Levels of most of the pollutants measured was found to be higher than that reported by previous studies, especially that of benzo(a)pyrene. (author)

  7. Analysis of Thermo-Acoustic Emission from Damage in Composite Laminates under Thermal Cyclic Loading

    International Nuclear Information System (INIS)

    Kim, Young Bok; Min, Dae Hong; Lee, Deok Bo; Choi, Nak Sam

    2001-01-01

    An investigation on nondestructive evaluation of thermal stress-reduced damage in the composite laminates (3mm in thickness and [+45 6 /-45 6 ] S lay-up angles) has been performed using the thermo-acoustic emission technique. Reduction of thermo-AE events due to repetitive thermal load cycles showed a Kaiser effect. An analysis of the thermo-AE behavior determined the stress free temperature of composite laminates. Fiber fracture and matrix cracks were observed using the optical microscopy, scanning electron microscopy and ultrasonic C-sean. Short-Time Fourier Transform of thermo-AE signals offered the time-frequency characteristics which might classify the thermo-AE as three different types to estimate the damage processes of the composites

  8. Removal properties of low-thermal-expansion materials with rotating-sphere elastic emission machining

    Directory of Open Access Journals (Sweden)

    Masahiko Kanaoka et al

    2007-01-01

    Full Text Available Optical mirrors used in extreme ultraviolet lithography systems require a figure accuracy and a roughness of about 0.1 nm rms. In addition, mirror substrates must be low-thermal-expansion materials. Thus, in this study, we processed two low-thermal-expansion materials, ULE [K. Hrdina, B. Hanson, P. Fenn, R. Sabia, Proc. SPIE 4688 (2002 454.] (Corning Inc. and Zerodur [I. Mitra, M.J. Davis, J. Alkemper, Rolf Müller, H. Kohlmann, L. Aschke, E. Mörsen, S. Ritter, H. Hack, W. Pannhorst, Proc. SPIE 4688 (2002 462.] (SCHOTT AG, with elastic emission machining (EEM in order to evaluate the removal properties. Consequently, we successfully calculated the respective removal rates, because removal volumes were found to be proportional to process times in EEM. Moreover, we demonstrated that the surface roughness of Zerodur is reduced to 0.1 nm rms in the spatial wavelength range from 100 μm to 1 mm.

  9. Thermal and UV Hydrosilylation of Alcohol-Based Bifunctional Alkynes on Si (111) surfaces: How surface radicals influence surface bond formation.

    Science.gov (United States)

    Khung, Y L; Ngalim, S H; Scaccabarozi, A; Narducci, D

    2015-06-12

    Using two different hydrosilylation methods, low temperature thermal and UV initiation, silicon (111) hydrogenated surfaces were functionalized in presence of an OH-terminated alkyne, a CF3-terminated alkyne and a mixed equimolar ratio of the two alkynes. XPS studies revealed that in the absence of premeditated surface radical through low temperature hydrosilylation, the surface grafting proceeded to form a Si-O-C linkage via nucleophilic reaction through the OH group of the alkyne. This led to a small increase in surface roughness as well as an increase in hydrophobicity and this effect was attributed to the surficial etching of silicon to form nanosize pores (~1-3 nm) by residual water/oxygen as a result of changes to surface polarity from the grafting. Furthermore in the radical-free thermal environment, a mix in equimolar of these two short alkynes can achieve a high contact angle of ~102°, comparable to long alkyl chains grafting reported in literature although surface roughness was relatively mild (rms = ~1 nm). On the other hand, UV initiation on silicon totally reversed the chemical linkages to predominantly Si-C without further compromising the surface roughness, highlighting the importance of surface radicals determining the reactivity of the silicon surface to the selected alkynes.

  10. First-principles calculations of orientation dependence of Si thermal oxidation based on Si emission model

    Science.gov (United States)

    Nagura, Takuya; Kawachi, Shingo; Chokawa, Kenta; Shirakawa, Hiroki; Araidai, Masaaki; Kageshima, Hiroyuki; Endoh, Tetsuo; Shiraishi, Kenji

    2018-04-01

    It is expected that the off-state leakage current of MOSFETs can be reduced by employing vertical body channel MOSFETs (V-MOSFETs). However, in fabricating these devices, the structure of the Si pillars sometimes cannot be maintained during oxidation, since Si atoms sometimes disappear from the Si/oxide interface (Si missing). Thus, in this study, we used first-principles calculations based on the density functional theory, and investigated the Si emission behavior at the various interfaces on the basis of the Si emission model including its atomistic structure and dependence on Si crystal orientation. The results show that the order in which Si atoms are more likely to be emitted during thermal oxidation is (111) > (110) > (310) > (100). Moreover, the emission of Si atoms is enhanced as the compressive strain increases. Therefore, the emission of Si atoms occurs more easily in V-MOSFETs than in planar MOSFETs. To reduce Si missing in V-MOSFETs, oxidation processes that induce less strain, such as wet or pyrogenic oxidation, are necessary.

  11. High-resolution spectroscopic search for the thermal emission of the extrasolar planet HD 217107 b

    OpenAIRE

    Cubillos, Patricio E.; Rojo, Patricio; Fortney, Jonathan J.

    2011-01-01

    We analyzed the combined near-infrared spectrum of a star-planet system with thermal emission atmospheric models, based on the composition and physical parameters of the system. The main objective of this work is to obtain the inclination of the orbit, the mass of the exoplanet, and the planet-to-star flux ratio. We present the results of our routines on the planetary system HD 217107, which was observed with the high-resolution spectrograph Phoenix at 2.14 microns. We revisited and tuned a c...

  12. Acoustic emission studies of cermet BK structural modifications under thermal and radiation action and hydrogenation

    International Nuclear Information System (INIS)

    Ul'yanov, V.L.; Chernov, I.P.; Botaki, A.A.; Chakhlov, B.V.

    1992-01-01

    Elastic wave attenuation and acoustic emission (AE) in tungsten monocarbide base cermets were investigated with the purpose of studying structural changes and microplastic strains under heating within the range of 100-1000 K, gamma-irradiation up to absorbed dose of 10 7 J·kg -1 and hydrogenation. Interrelations were revealed of AE signals and a decrement of elastic wave damping to temperature- and radiation-induced transformations in microstructure of 94 % WC -6 % Co and 92 % WC - 8 % Co hard alloys. AE peaks under thermal action were found to be associated with cobalt phase microstrain or with dislocation of hydrogen in preliminary hyudrogenated alloys

  13. Thermal Emission Control via Bandgap Engineering in Aperiodically Designed Nanophotonic Devices

    Directory of Open Access Journals (Sweden)

    Enrique Maciá

    2015-05-01

    Full Text Available Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of thermal emission/absorption control on the basis of the systematic use of aperiodic multilayer designs in photonic quasicrystals. Then, we illustrate the potential applications of this approach in order to enhance the performance of daytime radiative coolers and solar thermoelectric energy generators.

  14. Geometry of the non-thermal emission in SN 1006. Azimuthal variations of cosmic-ray acceleration

    OpenAIRE

    Rothenflug, R.; Ballet, J.; Dubner, Gloria Mabel; Giacani, Elsa Beatriz; Decourchelle, A.; Ferrando, P.

    2017-01-01

    SN 1006 is the prototype of shell supernova remnants, in which non-thermal synchrotron emission dominates the X-ray spectrum. The non-thermal emission is due to the cosmic-ray electrons accelerated behind the blast wave. The X-ray synchrotron emission is due to the highest energy electrons, and is thus a tracer of the maximum energy electrons may reach behind a shock. We have put together all XMM-Newton observations to build a full map of SN 1006. The very low brightness a...

  15. Thermoluminescence sensitivity of ulexite after UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mats@cu.edu.tr [Cukurova University, Arts-Sciences Faculty, Physics Department, 01330 Adana (Turkey); CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, (CSIC), C/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

    2015-04-15

    Highlights: •UV-induced thermoluminescence emission of Turkish ulexite was studied. •There are three groups of components. •The UV exposures were performed at controlled temperatures. -- Abstract: The effects of UV radiation on the thermoluminescence (TL) properties of natural materials, in contrast to synthetic materials, have been scarcely studied. We report on the UV-induced thermoluminescence emission of a Turkish ulexite (NaCaB{sub 5}O{sub 6}(OH){sub 6}·5H{sub 2}O) that displays very complex TL glow curves, with at least three groups of components peaked at 130–140 °C, 240 °C and, 340 °C, wherein the last group is weaker. Such emission could be associated with structural changes in the lattice as well as alkali self-diffusion processes. The UV exposure performed at controlled temperatures (at room temperature (RT), 50 °C and 100 °C) produced a (i) different evolutions of the intensities of each maximum, which are directly related to the controlled thermal treatment; (ii) different intensity ratios among the groups of components; (iii) different activation energies (E{sub a}) (1.13 eV for RT, 0.99 eV for 50 °C and 0.49 eV for 100 °C) calculated using the initial rise method; and (iv) similar scattering values (12.4%, 8.2% and 12.8%), which were not a function of the controlled temperature. The thermal stability tests conducted on this borate at different temperatures, based on the T{sub stop} protocol, confirm the presence of a continuum in the distribution of the trap system with progressively increasing E{sub a} (from 0.60 to 0.90 eV)

  16. Ultra High Resolution Imaging of Enceladus Tiger Stripe Thermal Emission with Cassini CIRS

    Science.gov (United States)

    Spencer, John R.; Gorius, Nicolas; Howett, Carly; Verbiscer, Anne J.; Cassini CIRS Team

    2017-10-01

    In October 2015, Cassini flew within 48 km of Enceladus’ south pole. The spacecraft attitude was fixed during the flyby, but the roll angle of the spacecraft was chosen so that the remote sensing instrument fields of view passed over Damascus, Baghdad, and Cairo Sulci. The Composite Infrared Spectrometer (CIRS) instrument obtained a single interferometer scan during the flyby, using a special mode, enabled by a flight software update, which bypassed numerical filters to improve the fidelity of the interferograms. This generated a total of 11 interferograms, at 5 contiguous spatial locations for each of the 7 - 9 micron (FP4) and 9 - 17 micron (FP3) focal planes, and a single larger field of view for the 17 - 500 micron focal plane (FP1). Strong spikes were seen in the interferograms when crossing each of the sulci, due to the rapid passage of warm material through the field of view. For FP3 and FP4, the temporal variations of the signals from the 5 contiguous detectors can be used to generated 5-pixel-wide images of the thermal emission, which show excellent agreement between the two focal planes. FP3 and FP4 spatial resolution, limited along track by the 5 msec time sampling of the interferogram, and across track by the CIRS field of view, is a remarkable 40 x 40 meters. At this resolution, the tiger stripe thermal emission shows a large amount of structure, including both continuous emission along the fractures, discrete hot spots less than 100 meters across, and extended emission with complex structure.

  17. Probabilistic multiobjective wind-thermal economic emission dispatch based on point estimated method

    International Nuclear Information System (INIS)

    Azizipanah-Abarghooee, Rasoul; Niknam, Taher; Roosta, Alireza; Malekpour, Ahmad Reza; Zare, Mohsen

    2012-01-01

    In this paper, wind power generators are being incorporated in the multiobjective economic emission dispatch problem which minimizes wind-thermal electrical energy cost and emissions produced by fossil-fueled power plants, simultaneously. Large integration of wind energy sources necessitates an efficient model to cope with uncertainty arising from random wind variation. Hence, a multiobjective stochastic search algorithm based on 2m point estimated method is implemented to analyze the probabilistic wind-thermal economic emission dispatch problem considering both overestimation and underestimation of available wind power. 2m point estimated method handles the system uncertainties and renders the probability density function of desired variables efficiently. Moreover, a new population-based optimization algorithm called modified teaching-learning algorithm is proposed to determine the set of non-dominated optimal solutions. During the simulation, the set of non-dominated solutions are kept in an external memory (repository). Also, a fuzzy-based clustering technique is implemented to control the size of the repository. In order to select the best compromise solution from the repository, a niching mechanism is utilized such that the population will move toward a smaller search space in the Pareto-optimal front. In order to show the efficiency and feasibility of the proposed framework, three different test systems are represented as case studies. -- Highlights: ► WPGs are being incorporated in the multiobjective economic emission dispatch problem. ► 2m PEM handles the system uncertainties. ► A MTLBO is proposed to determine the set of non-dominated (Pareto) optimal solutions. ► A fuzzy-based clustering technique is implemented to control the size of the repository.

  18. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

    Science.gov (United States)

    Karthikeya Sharma, T

    2015-11-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied.

  19. Reversible manipulation of the adhesive forces of TiO{sub 2}/polybenzoxazine nanoassembled coatings through UV irradiation and thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Sheng-Feng; Kao, Tzu-Hao [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei 106, Taiwan, ROC (China); Cheng, Chih-Chia [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC (China); Chang, Chi-Jung [Department of Chemical Engineering, Feng Chia University, 100, Wenhwa Road, Seatwen, Taichung 40724, Taiwan, ROC (China); Chen, Jem-Kun, E-mail: jkchen@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei 106, Taiwan, ROC (China)

    2015-12-01

    Graphical abstract: We developed a simple approach, mixing TiO{sub 2} nanoparticles and 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine (BA), to obtain a UV-responsive surfaces after thermal treatment. Because the wettability between TiO{sub 2} nanoparticles and BA, a nanoassembled structure was generated on the surface during the coating process. Results indicate that the mixing 30 wt% TiO{sub 2} nanoparticles into PBA matrix generated the superhydrophobic surface (static water contact angle > 150°) with ca. 1° of sliding angle. The superhydrophobic TiO{sub 2}/PBA nanoassembled surface can be converted by photocatalytic oxidation into a highly hydrophilic one (static water contact angle ∼ 0°) within five minimums. Interestingly, the hydrophilic surface can be converted back into a superhydrophobic surface by heat treatment. A water droplet can be transported among the surfaces that UV-irradiated for various times. Velocity of the droplet on the 15°-titled surface could be also manipulated with UV irradiation for various times. The correlations between PBA and TiO{sub 2} nanoparticles would provide insight into the designing and developing of light-responsive surfaces. - Highlights: • Nanoassembly of PBA and TiO{sub 2} NPs are generated with superhydrophobicity. • The superhydrophobicity can be converted to hydrophilic surface within 5 min. • The hydrophilic surface can be converted back into a superhydrophobic surface. • Adhesive force of the nanoassemblies can be manipulated by UV illumination time. - Abstract: In this study we mixed TiO{sub 2} nanoparticles (NPs) with 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine (BA), as a precursor to a polybenzoxazine (PBA), to generate nanocomposite surfaces possessing low surface free energies. Because of extreme phase separation between the TiO{sub 2} NPs and BA, their mixtures featured nanoassembled structures on their surfaces. After thermal curing, we obtained PBA/TiO{sub 2} nanoassembled (PTN) surfaces possessing

  20. NON-THERMAL EMISSION FROM CATACLYSMIC VARIABLES: IMPLICATIONS ON ASTROPARTICLE PHYSICS

    Directory of Open Access Journals (Sweden)

    Vojtech Šimon

    2013-12-01

    Full Text Available We review the lines of evidence that some cataclysmic variables (CVs are the sources of non-thermal radiation. It was really observed in some dwarf novae in outburst, a novalike CV in the high state, an intermediate polar, polars, and classical novae (CNe during outburst. The detection of this radiation suggests the presence of highly energetic particles in these CVs. The conditions for the observability of this emission depend on the state of activity, and the system parameters. We review the processes and conditions that lead to the production of this radiation in various spectral bands, from gamma-rays including TeV emission to radio. Synchrotron and cyclotron emissions suggest the presence of strong magnetic fields in CV. In some CVs, e.g. during some dwarf nova outbursts, the magnetic field generated in the accretion disk leads to the synchrotron jets radiating in radio. The propeller effect or a shock in the case of the magnetized white dwarf (WD can lead to a strong acceleration of the particles that produce gamma-ray emission via pi0 decay; even Cherenkov radiation is possible. In addition, a gamma-ray production via pi0 decay was observed in the ejecta of an outburst of a symbiotic CN. Nuclear reactions during thermonuclear runaway in the outer layer of the WD undergoing CN outburst lead to the production of radioactive isotopes; their decay is the source of gamma-ray emission. The production of accelerated particles in CVs often has episodic character with a very small duty cycle; this makes their detection and establishing the relation of the behavior in various bands difficult.

  1. Dynamics of the cavity radiation of a correlated emission laser initially seeded with a thermal light

    Energy Technology Data Exchange (ETDEWEB)

    Tesfa, Sintayehu, E-mail: sint_tesfa@yahoo.com [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Street 38, 01187 Dresden (Germany); Physics Department, Dilla University, PO Box 419, Dilla (Ethiopia)

    2011-10-15

    A detailed analysis of the time evolution of the two-mode squeezing, entanglement and intensity of the cavity radiation of a two-photon correlated emission laser initially seeded with a thermal light is presented. The dependences of the degree of two-mode squeezing and entanglement on the intensity of the thermal light and time are found to have a more or less similar nature, although the actual values differ, especially in the early stages of the process and when the atoms are initially prepared with nearly 50:50 probability to be in the upper and lower energy levels. Seeding the cavity degrades the nonclassical features significantly, particularly in the vicinity of t=0. It is also shown that the mean photon number in a wider time span has a dip when mode b is seeded but a peak when mode a is seeded. Moreover, it turns out that the effect of the seed light on the nonclassical features and intensity of the cavity radiation decreases significantly with time, an outcome essentially attributed to the pertinent emission-absorption mechanism. This can be taken as an encouraging aspect in the practical utilization of this model as a source of a bright entangled light.

  2. Comparison of organic emissions from laboratory and full-scale thermal degradation of sewage sludge

    International Nuclear Information System (INIS)

    Tirey, D.A.; Striebich, R.C.; Dellinger, B.; Bostian, H.E.

    1991-01-01

    Samples of sewage sludge burned at one fluidized-bed and three multiple-hearth incinerators were subjected to laboratory flow reactor thermal decomposition testing in both pyrolytic and oxidative atmospheres. The time/temperature conditions of the laboratory testing were established to simulate as closely as possible full-scale incineration conditions so that a direct comparison of results could be made. The laboratory test results indicated that biomass decomposition products, not toxic industrial contaminants, comprised the majority of the emissions. Benzene, toluene, ethylbenzene, acrylonitrile, and acetonitrile were consistently the most environmentally significant products of thermal degradation. Comparison of the results from this study with those obtained in field tests was complicated by an apparent loss of volatile chlorocarbons from the sludge samples received for laboratory testing. However, qualitative comparison of emission factors derived from lab and field results for those compounds observed in both studies, showed reasonably good correlation for the pyrolysis testing. Results suggested that the upper stages of multiple-hearth units may vaporize many volatile components of the sludge before they enter the combustion stages of the incinerator and thus represent a direct source of introduction of pollutants into the atmosphere

  3. A method to quickly test the emissivity with an infrared thermal imaging system within a small distance

    Science.gov (United States)

    Wang, Xuan-yu; Hu, Rui; Wang, Rui-xin

    2015-10-01

    A simple method has been set up to quickly test the emissivity with an infrared thermal imaging system within a small distance according to the theory of measuring temperature by infrared system, which is based on the Planck radiation law and Lambert-beer law. The object's temperature is promoted and held on by a heater while a temperature difference has been formed between the target and environment. The emissivity of human skin, galvanized iron plate, black rubber and liquid water has been tested under the condition that the emissivity is set in 1.0 and the testing distance is 1m. According to the invariance of human's body temperature, a testing curve is established to describe that the thermal imaging temperatures various with the emissivity which is set in from 0.9 to 1.0. As a result, the method has been verified. The testing results show that the emissivity of human skin is 0.95. The emissivity of galvanized iron plate, black rubber and liquid water decreases with the increase of object's temperature. The emissivity of galvanized iron plate is far smaller than the one of human skin, black rubber or water. The emissivity of water slowly linearly decreases with the increase of its temperature. By the study, within a small distance and clean atmosphere, the infrared emissivity of objects may be expediently tested with an infrared thermal imaging system according to the method, which is promoting the object's temperature to make it different from the environment temperature, then simultaneously measures the environmental temperature, the real temperature and thermal imaging temperature of the object when the emissivity is set in 1.0 and the testing distance is 1.0m.

  4. Numerical investigation of CO{sub 2} emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe of variable thermal conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Lebelo, Ramoshweu Solomon, E-mail: sollyl@vut.ac.za [Department of Mathematics, Vaal University of Technology, Private Bag X021, Vanderbijlpark, 1911 (South Africa)

    2014-10-24

    In this paper the CO{sub 2} emission and thermal stability in a long cylindrical pipe of combustible reactive material with variable thermal conductivity are investigated. It is assumed that the cylindrical pipe loses heat by both convection and radiation at the surface. The nonlinear differential equations governing the problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique method. The effects of various thermophysical parameters on the temperature and carbon dioxide fields, together with critical conditions for thermal ignition are illustrated and discussed quantitatively.

  5. VARIABILITY OF THE SiO THERMAL LINE EMISSION TOWARD THE YOUNG L1448-mm OUTFLOW

    International Nuclear Information System (INIS)

    Jimenez-Serra, I.; MartIn-Pintado, J.; RodrIguez-Franco, A.; Winters, J.-M.; Caselli, P.

    2011-01-01

    The detection of narrow SiO thermal emission toward young outflows has been proposed to be a signature of the magnetic precursor of C-shocks. Recent modeling of the SiO emission across C-shocks predicts variations in the SiO line intensity and line shape at the precursor and intermediate-velocity regimes in only a few years. We present high angular resolution (3.''8 x 3.''3) images of the thermal SiO J = 2→1 emission toward the L1448-mm outflow in two epochs (2004 November-2005 February, 2009 March-April). Several SiO condensations have appeared at intermediate velocities (20-50 km s -1 ) toward the redshifted lobe of the outflow since 2005. Toward one of the condensations (clump D), systematic differences of the dirty beams between 2005 and 2009 could be responsible for the SiO variability. At higher velocities (50-80 km s -1 ), SiO could also have experienced changes in its intensity. We propose that the SiO variability toward L1448-mm is due to a real SiO enhancement by young C-shocks at the internal working surface between the jet and the ambient gas. For the precursor regime (5.2-9.2 km s -1 ), several narrow and faint SiO components are detected. The narrow SiO components tend to be compact, transient and show elongated (bow-shock) morphologies perpendicular to the jet. We speculate that these features are associated with the precursor of C-shocks appearing at the interface of the new SiO components seen at intermediate velocities.

  6. Investigation of EBW Thermal Emission and Mode Conversion Physics in H-Mode Plasmas on NSTX

    International Nuclear Information System (INIS)

    Diem, S.J.; Taylor, G.; Efthimion, P.C.; Kugel, H.W.; LeBlanc, B.P.; Phillips, C.K.; Caughman, J.B.; Wilgen, J.B.; Harvey, R.W.; Preinhaelter, J.; Urban, J.; Sabbagh, S.A.

    2008-01-01

    High β plasmas in the National Spherical Torus Experiment (NSTX) operate in the overdense regime, allowing the electron Bernstein wave (EBW) to propagate and be strongly absorbed/emitted at the electron cyclotron resonances. As such, EBWs may provide local electron heating and current drive. For these applications, efficient coupling between the EBWs and electromagnetic waves outside the plasma is needed. Thermal EBW emission (EBE) measurements, via oblique B-X-O double mode conversion, have been used to determine the EBW transmission efficiency for a wide range of plasma conditions on NSTX. Initial EBE measurements in H-mode plasmas exhibited strong emission before the L-H transition, but the emission rapidly decayed after the transition. EBE simulations show that collisional damping of the EBW prior to the mode conversion (MC) layer can significantly reduce the measured EBE for T e < 20 eV, explaining the observations. Lithium evaporation was used to reduce EBE collisional damping near the MC layer. As a result, the measured B-X-O transmission efficiency increased from < 10% (no Li) to 60% (with Li), consistent with EBE simulations.

  7. Thermal and nonthermal electron cyclotron emission by high-temperature tokamak plasmas

    International Nuclear Information System (INIS)

    Airoldi, A.; Ramponi, G.

    1997-01-01

    An analysis of the electron cyclotron emission (ECE) spectra emitted by a high-temperature tokamak plasma in the frequency range of the second and third harmonic of the electron cyclotron frequency is made, both in purely Maxwellian and in non-Maxwellian cases (i.e., in the presence of a current-carrying superthermal tail). The work is motivated mainly by the experimental observations made in the supershot plasmas of the Tokamak Fusion Test Reactor (TFTR), where a systematic disagreement is found between the T e measurements by second-harmonic ECE and Thomson scattering. We show that, by properly taking into account the overlap of superthermals-emitted third harmonic with second-harmonic bulk emission, the radiation temperature observed about the central frequency of the second harmonic may be enhanced up to 30%endash 40% compared to the corresponding thermal value. Moreover we show that, for parameters relevant to the International Thermonuclear Experimental Reactor (ITER) with T e (0)>7 keV, the overlap between the second and the downshifted third harmonic seriously affects the central plasma region, so that the X-mode emission at the second harmonic becomes unsuitable for local T e measurements. copyright 1997 American Institute of Physics

  8. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    Energy Technology Data Exchange (ETDEWEB)

    Sasao, M. (National Inst. for Fusion Science, Nagoya (Japan)); Adam, J.M. (AEA Industrial Technology, Harwell (United Kingdom)); Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking)

    1992-01-01

    Spatial profiles of neutron emission are routinely obtained at the Joint European Torus (JET) from line-integrated emissivities measured with a multi-channel instrument. It is shown that the manner in which the emission profiles relax following termination of strong heating with Neutral Beam Injection (NBI) permits the local thermal diffusivity ([chi][sub i]) to be obtained with an accuracy of about 20%. The radial profiles of [chi][sub i] for small minor radius (r/a < 0.6) were found to be flat and to take values between 0.3 and 1.1 m[sup 2]/s for H-mode plasmas with plasma current I[sub p] = 3.1 MA and toroidal field B[sub T] = 2.3T. The experimental value of [chi][sub i] is smallest for Z[sub eff] = 2.2 and increases weakly with increasing Z[sub eff]. The experimental results disagree by two orders of magnitude with predictions from an ion temperature gradient driven turbulence model. (author) 6 refs., 3 figs.

  9. Radiative thermal emission from silicon nanoparticles: a reversed story from quantum to classical theory

    International Nuclear Information System (INIS)

    Roura, P.; Costa, J.

    2002-01-01

    Among the rush of papers published after the discovery of visible luminescence in porous silicon, a number of them claimed that an extraordinary behaviour had been found. However, after five years of struggling with increasingly sophisticated but not completely successful models, it was finally demonstrated that it was simply thermal radiation. Here, we calculate thermal radiation emitted by silicon nanoparticles when irradiated in vacuum with a laser beam. If one interprets this radiation as being photoluminescence, its properties appear extraordinary: non-exponential excitation and decay transients and a supralinear dependence on laser power. Within the (quantum) theory of photoluminescence, this behaviour can be interpreted as arising from a non-usual excitation mechanism known as multiphoton excitation. Although this erroneous interpretation has, to some extent, a predictive power, it is unable to give a sound explanation for the quenching of radiation when particles are not irradiated in vacuum but inside a gas. The real story of this error is presented both to achieve a deeper understanding of the radiative thermal emission of nanoparticles and as a matter of reflection on scientific activity. (author)

  10. Impact Analysis of Air Pollutant Emission Policies on Thermal Coal Supply Chain Enterprises in China

    Directory of Open Access Journals (Sweden)

    Xiaopeng Guo

    2014-12-01

    Full Text Available Spurred by the increasingly serious air pollution problem, the Chinese government has launched a series of policies to put forward specific measures of power structure adjustment and the control objectives of air pollution and coal consumption. Other policies pointed out that the coal resources regional blockades will be broken by improving transportation networks and constructing new logistics nodes. Thermal power takes the largest part of China’s total installed power generation capacity, so these policies will undoubtedly impact thermal coal supply chain member enterprises. Based on the actual situation in China, this paper figures out how the member enterprises adjust their business decisions to satisfy the requirements of air pollution prevention and control policies by establishing system dynamic models of policy impact transfer. These dynamic analyses can help coal enterprises and thermal power enterprises do strategic environmental assessments and find directions of sustainable development. Furthermore, the policy simulated results of this paper provide the Chinese government with suggestions for policy-making to make sure that the energy conservation and emission reduction policies and sustainable energy policies can work more efficiently.

  11. New ultrafast X-ray sources and their applications. Coherent ultrashort X UV emission by harmonic generation

    International Nuclear Information System (INIS)

    Salieres, P.; Le deroff, L.; Hergott, J.F.; Merdji, H.; Carre, B.

    2000-01-01

    By focusing an intense short-pulse laser into a rare gas jet, high-order harmonics of the laser frequency are generated. Considerable progress have been made in the last few years, with the observation of harmonic orders higher that 200, extending the emission down to 3 nm. Besides its fundamental interest, this XUV emission represents a new source with unique properties of coherence and ultrashort (femtosecond) duration. A growing number of applications are reported, ranging from atomic and molecular spectroscopy to solid-state and plasma physics. (authors)

  12. Thermal Effect on a CIGS Thin-Film Solar Cell P2 Layer by Using a UV Laser

    Directory of Open Access Journals (Sweden)

    Dyi-Cheng Chen

    2014-07-01

    Full Text Available This study used ANSYS simulation software for analyzing an ultraviolet (UV (355 nm laser processing system. The laser apparatus was used in a stainless steel CIGS solar cell P2 layer for simulation analysis. CIGS films process order according to SiO2 layer, molybdenum electrode, CIGS absorbed layer, CdS buffered layer, i-ZnO penetrate light layer, TCO front electrode, MgF resist reflected materials, andelectrode materials. The simulation and experimental results were compared to obtain a laser-delineated P2 laser with a low melting and vaporization temperature. According to the simulation results, the laser function time was 135 μs, the UV laser was 0.5 W, and the P2 layer thin films were removed. The experimental results indicated that the electrode pattern of the experiment was similar to that of the simulation result, and the laser process did not damage the base plate. The analysis results confirm that the laser apparatus is effective when applied to a stainless steel CIGS solar cell P2 layer.

  13. Mechanical, relaxation behavior and thermal degradation of UV irradiated poly(vinyl acetate)/poly( methyl methacrylate) blends

    International Nuclear Information System (INIS)

    Mansour, S.A.; Hafez, M.; Hussien, K.A.

    2005-01-01

    The effect of different doses of UV- irradiation on the mechanical and relaxation properties of poly(vinyl acetate)/poly(methyl methacrylate) blends were studied. Films of PVAc/PMMA blend with different contents were prepared using the casting technique. Also, PMMA could be blended with PVAc to improve its impact strength. Moreover UV-irradiation causes degradation of PVAc and formation of ketonic and aldehyde carbonyl groups according to a suggested scheme. Irradiation of PvAc/ PMMA blends causes a higher degree of degradation as compared to the PVAc alone although the PMMA is more susceptible than PVAc to the influence of radiation. Recognizable differences are observed for all parameters between the unirradiated and irradiated samples. Existence of a relaxation mechanism within the first 200s is reported. The shear modulus for all samples is also obtained and discussed. These data are used to calculate the strain energy density using the equation proposed by Blatzetal(1974 trans. Soc.Rheol. 18 145-61), based on the n-measure of Sethe

  14. Development of a non-thermal accelerated pulsed UV photolysis assisted digestion method for fresh and dried food samples

    International Nuclear Information System (INIS)

    Solis, C.; Lagunas-Solar, M.C.; Perley, B.P.; Pina, C.; Aguilar, L.F.; Flocchini, R.G.

    2002-01-01

    A simple, fast digestion procedure for fresh and dried foods, using high-power pulsed UV photolysis in the presence of hydrogen peroxide, is being developed. The homogenized food samples were mixed with H 2 O 2 or with a mixture of H 2 O 2 and HNO 3 , and irradiated for short times with a 248-nm UV excimer laser. After centrifugation, a clear, colorless solution was obtained and aliquots were deposited on Teflon filters for XRF and/or PIXE analyses. Standard reference materials (NIST Peach Leaves; Typical Diet) were also analyzed to compare recoveries and detection limits. Improvements in detection limits were observed, but a few trace elements (<1 ppm) were not reproducibly detected (Fe, Sr). This method proved to be practical for the accelerated digestion of food samples and preparing analytes in short-time intervals. In combination with PIXE and XRF, it allows high-sensitivity multi-elemental analyses for screening the nutritional elements and for food safety purposes regarding the potential presence of toxic elements. Further development to optimize and validate this procedure for a broader range of analytes is in progress

  15. Assessment of DNA degradation induced by thermal and UV radiation processing: implications for quantification of genetically modified organisms.

    Science.gov (United States)

    Ballari, Rajashekhar V; Martin, Asha

    2013-12-01

    DNA quality is an important parameter for the detection and quantification of genetically modified organisms (GMO's) using the polymerase chain reaction (PCR). Food processing leads to degradation of DNA, which may impair GMO detection and quantification. This study evaluated the effect of various processing treatments such as heating, baking, microwaving, autoclaving and ultraviolet (UV) irradiation on the relative transgenic content of MON 810 maize using pRSETMON-02, a dual target plasmid as a model system. Amongst all the processing treatments examined, autoclaving and UV irradiation resulted in the least recovery of the transgenic (CaMV 35S promoter) and taxon-specific (zein) target DNA sequences. Although a profound impact on DNA degradation was seen during the processing, DNA could still be reliably quantified by Real-time PCR. The measured mean DNA copy number ratios of the processed samples were in agreement with the expected values. Our study confirms the premise that the final analytical value assigned to a particular sample is independent of the degree of DNA degradation since the transgenic and the taxon-specific target sequences possessing approximately similar lengths degrade in parallel. The results of our study demonstrate that food processing does not alter the relative quantification of the transgenic content provided the quantitative assays target shorter amplicons and the difference in the amplicon size between the transgenic and taxon-specific genes is minimal. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weiyang; Lu, Jiguang; Men, Yunpeng; Xu, Renxin [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Tong, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Ge, Mingyu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Zhaosheng, E-mail: r.x.xu@pku.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  17. Photocatalytic decomposition of selected estrogens and their estrogenic activity by UV-LED irradiated TiO_2 immobilized on porous titanium sheets via thermal-chemical oxidation

    International Nuclear Information System (INIS)

    Arlos, Maricor J.; Liang, Robert; Hatat-Fraile, Melisa M.; Bragg, Leslie M.; Zhou, Norman Y.; Servos, Mark R.; Andrews, Susan A.

    2016-01-01

    Highlights: • TiO_2 self-assembled on oxidized porous titanium sheets. • UV-LED/TiO_2 membrane treatment reduced the concentrations of estrogens. • Different pH conditions affect treatment efficiency. • The estrogenic activity removal was similar to the chemical disappearance. - Abstract: The removal of endocrine disrupting compounds (EDCs) remains a big challenge in water treatment. Risks associated with these compounds are not clearly defined and it is important that the water industry has additional options to increase the resiliency of water treatment systems. Titanium dioxide (TiO_2) has potential applications for the removal of EDCs from water. TiO_2 has been immobilized on supports using a variety of synthesis methods to increase its feasibility for water treatment. In this study, we immobilized TiO_2 through the thermal-chemical oxidation of porous titania sheets. The efficiency of the material to degrade target EDCs under UV-LED irradiation was examined under a wide range of pH conditions. A yeast-estrogen screen assay was used to complement chemical analysis in assessing removal efficiency. All compounds but 17β-estradiol were degraded and followed a pseudo first-order kinetics at all pH conditions tested, with pH 4 and pH 11 showing the most and the least efficient treatments respectively. In addition, the total estrogenic activity was substantially reduced even with the inefficient degradation of 17β-estradiol. Additional studies will be required to optimize different treatment conditions, UV-LED configurations, and membrane fouling mitigation measures to make this technology a more viable option for water treatment.

  18. Thermal Emission of Alkali Metal Ions from Al30-Pillared Montmorillonite Studied by Mass Spectrometric Method.

    Science.gov (United States)

    Motalov, V B; Karasev, N S; Ovchinnikov, N L; Butman, M F

    2017-01-01

    The thermal emission of alkali metal ions from Al 30 -pillared montmorillonite in comparison with its natural form was studied by mass spectrometry in the temperature range 770-930 K. The measurements were carried out on a magnetic mass spectrometer MI-1201. For natural montmorillonite, the densities of the emission currents ( j ) decrease in the mass spectrum in the following sequence (T = 805 K, A/cm 2 ): K + (4.55 · 10 -14 ), Cs + (9.72 · 10 -15 ), Rb + (1.13 · 10 -15 ), Na + (1.75 · 10 -16 ), Li + (3.37 · 10 -17 ). For Al 30 -pillared montmorillonite, thermionic emission undergoes temperature-time changes. In the low-temperature section of the investigated range (770-805 K), the value of j increases substantially for all ions in comparison with natural montmorillonite (T = 805 K, A/cm 2 ): Cs + (6.47 · 10 -13 ), K + (9.44 · 10 -14 ), Na + (3.34 · 10 -15 ), Rb + (1.77 · 10 -15 ), and Li + (4.59 · 10 -16 ). A reversible anomaly is observed in the temperature range 805-832 K: with increasing temperature, the value of j of alkaline ions falls abruptly. This effect increases with increasing ionic radius of M + . After a long heating-up period, this anomaly disappears and the ln j - 1/ T dependence acquires a classical linear form. The results are interpreted from the point of view of the dependence of the efficiency of thermionic emission on the phase transformations of pillars.

  19. Thermal Emission of Alkali Metal Ions from Al30-Pillared Montmorillonite Studied by Mass Spectrometric Method

    Directory of Open Access Journals (Sweden)

    V. B. Motalov

    2017-01-01

    Full Text Available The thermal emission of alkali metal ions from Al30-pillared montmorillonite in comparison with its natural form was studied by mass spectrometry in the temperature range 770–930 K. The measurements were carried out on a magnetic mass spectrometer MI-1201. For natural montmorillonite, the densities of the emission currents (j decrease in the mass spectrum in the following sequence (T = 805 K, A/cm2: K+ (4.55 · 10−14, Cs+ (9.72 · 10−15, Rb+ (1.13 · 10−15, Na+ (1.75 · 10−16, Li+ (3.37 · 10−17. For Al30-pillared montmorillonite, thermionic emission undergoes temperature-time changes. In the low-temperature section of the investigated range (770–805 K, the value of j increases substantially for all ions in comparison with natural montmorillonite (T = 805 K, A/cm2: Cs+ (6.47 · 10−13, K+ (9.44 · 10−14, Na+ (3.34 · 10−15, Rb+ (1.77 · 10−15, and Li+ (4.59 · 10−16. A reversible anomaly is observed in the temperature range 805–832 K: with increasing temperature, the value of j of alkaline ions falls abruptly. This effect increases with increasing ionic radius of M+. After a long heating-up period, this anomaly disappears and the lnj-1/T dependence acquires a classical linear form. The results are interpreted from the point of view of the dependence of the efficiency of thermionic emission on the phase transformations of pillars.

  20. On the Spatially Resolved Star Formation History in M51. I. Hybrid UV+IR Star Formation Laws and IR Emission from Dust Heated by Old Stars

    Science.gov (United States)

    Eufrasio, R. T.; Lehmer, B. D.; Zezas, A.; Dwek, E.; Arendt, R. G.; Basu-Zych, A.; Wiklind, T.; Yukita, M.; Fragos, T.; Hornschemeier, A. E.; Markwardt, L.; Ptak, A.; Tzanavaris, P.

    2017-12-01

    We present LIGHTNING, a new spectral energy distribution fitting procedure, capable of quickly and reliably recovering star formation history (SFH) and extinction parameters. The SFH is modeled as discrete steps in time. In this work, we assumed lookback times of 0-10 Myr, 10-100 Myr, 0.1-1 Gyr, 1-5 Gyr, and 5-13.6 Gyr. LIGHTNING consists of a fully vectorized inversion algorithm to determine SFH step intensities and combines this with a grid-based approach to determine three extinction parameters. We apply our procedure to the extensive far-UV-to-far-IR photometric data of M51, convolved to a common spatial resolution and pixel scale, and make the resulting maps publicly available. We recover, for M51a, a peak star formation rate (SFR) between 0.1 and 5 Gyr ago, with much lower star formation activity over the past 100 Myr. For M51b, we find a declining SFR toward the present day. In the outskirt regions of M51a, which includes regions between M51a and M51b, we recover an SFR peak between 0.1 and 1 Gyr ago, which corresponds to the effects of the interaction between M51a and M51b. We utilize our results to (1) illustrate how UV+IR hybrid SFR laws vary across M51 and (2) provide first-order estimates for how the IR luminosity per unit stellar mass varies as a function of the stellar age. From the latter result, we find that IR emission from dust heated by stars is not always associated with young stars and that the IR emission from M51b is primarily powered by stars older than 5 Gyr.

  1. MEASUREMENT OF TOTAL SITE MERCURY EMISSIONS FROM A CHLOR-ALKALI PLANT USING OPEN-PATH UV-DOAS

    Science.gov (United States)

    In December 2003, the EPA promulgated the National Emission Standard for Hazardous Air Pollutants for mercury cell chlor-alkali plants. In February 2004, the Natural Resources Defense Council filed petitions on the final rule in U.S. district court citing, among other issues, th...

  2. PCA-based approach for subtracting thermal background emission in high-contrast imaging data

    Science.gov (United States)

    Hunziker, S.; Quanz, S. P.; Amara, A.; Meyer, M. R.

    2018-03-01

    Aims.Ground-based observations at thermal infrared wavelengths suffer from large background radiation due to the sky, telescope and warm surfaces in the instrument. This significantly limits the sensitivity of ground-based observations at wavelengths longer than 3 μm. The main purpose of this work is to analyse this background emission in infrared high-contrast imaging data as illustrative of the problem, show how it can be modelled and subtracted and demonstrate that it can improve the detection of faint sources, such as exoplanets. Methods: We used principal component analysis (PCA) to model and subtract the thermal background emission in three archival high-contrast angular differential imaging datasets in the M' and L' filter. We used an M' dataset of β Pic to describe in detail how the algorithm works and explain how it can be applied. The results of the background subtraction are compared to the results from a conventional mean background subtraction scheme applied to the same dataset. Finally, both methods for background subtraction are compared by performing complete data reductions. We analysed the results from the M' dataset of HD 100546 only qualitatively. For the M' band dataset of β Pic and the L' band dataset of HD 169142, which was obtained with an angular groove phase mask vortex vector coronagraph, we also calculated and analysed the achieved signal-to-noise ratio (S/N). Results: We show that applying PCA is an effective way to remove spatially and temporarily varying thermal background emission down to close to the background limit. The procedure also proves to be very successful at reconstructing the background that is hidden behind the point spread function. In the complete data reductions, we find at least qualitative improvements for HD 100546 and HD 169142, however, we fail to find a significant increase in S/N of β Pic b. We discuss these findings and argue that in particular datasets with strongly varying observing conditions or

  3. 3D-HST emission line galaxies at z ∼ 2: discrepancies in the optical/UV star formation rates

    Energy Technology Data Exchange (ETDEWEB)

    Zeimann, Gregory R.; Ciardullo, Robin; Gebhardt, Henry; Gronwall, Caryl; Schneider, Donald P.; Hagen, Alex; Bridge, Joanna S.; Trump, Jonathan R. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Feldmeier, John [Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States)

    2014-08-01

    We use Hubble Space Telescope near-IR grism spectroscopy to examine the Hβ line strengths of 260 star-forming galaxies in the redshift range 1.90 < z < 2.35. We show that at these epochs, the Hβ star formation rate (SFR) is a factor of ∼1.8 higher than what would be expected from the systems' rest-frame UV flux density, suggesting a shift in the standard conversion between these quantities and SFR. We demonstrate that at least part of this shift can be attributed to metallicity, as Hβ is more enhanced in systems with lower oxygen abundance. This offset must be considered when measuring the SFR history of the universe. We also show that the relation between stellar and nebular extinction in our z ∼ 2 sample is consistent with that observed in the local universe.

  4. 3D-HST emission line galaxies at z ∼ 2: discrepancies in the optical/UV star formation rates

    International Nuclear Information System (INIS)

    Zeimann, Gregory R.; Ciardullo, Robin; Gebhardt, Henry; Gronwall, Caryl; Schneider, Donald P.; Hagen, Alex; Bridge, Joanna S.; Trump, Jonathan R.; Feldmeier, John

    2014-01-01

    We use Hubble Space Telescope near-IR grism spectroscopy to examine the Hβ line strengths of 260 star-forming galaxies in the redshift range 1.90 < z < 2.35. We show that at these epochs, the Hβ star formation rate (SFR) is a factor of ∼1.8 higher than what would be expected from the systems' rest-frame UV flux density, suggesting a shift in the standard conversion between these quantities and SFR. We demonstrate that at least part of this shift can be attributed to metallicity, as Hβ is more enhanced in systems with lower oxygen abundance. This offset must be considered when measuring the SFR history of the universe. We also show that the relation between stellar and nebular extinction in our z ∼ 2 sample is consistent with that observed in the local universe.

  5. SUPERFUND TREATABILITY CLEARINGHOUSE: TECHNOLOGY DEMONSTRATION OF A THERMAL DESORPTION/UV PHOTOLYSIS PROCESS FOR DECONTAMINATING SOILS CONTAINING HERBICIDE ORANGE

    Science.gov (United States)

    This treatability study report presents the results of laboratory and field tests on the effectiveness of a new decontamination process for soils containing 2,4-D/2,4,5-T and traces of dioxin. The process employs three operations, thermal desorption, condensation and absorp...

  6. Evaluation of gas emissions and environmental impact of a Cuban thermal power plant

    International Nuclear Information System (INIS)

    Colas Aroche, Juan Alberto; Alvarez Hernandez, Orlando H; Fuentes Quevedo, Eduardo; Teutelo Nunnez, Raisa

    2006-01-01

    The present work shows the results obtained in the characterization of gas emissions and the impact of two fire-tube boilers in a Cuban thermal power plant. The results of the SO 2 and NO X sampling were collected in specific solutions for each pollutant. The sampling of suspended particulates in chimneys/pipes/stacks was made by collecting them in a filterholder for their analysis by means of the gravimetric method. Flow measurements were also made by using pressure sensors of Pilot tube-type speedometers. The dispersion modelling of pollutants poured out of the chimneys was developed running the program for the concentration calculation from continuous industrial sources and following the methodology approved by the Cuban standard according to Berliand model. The authors conclude that when burning national crude oil in the studied boilers, sulphur dioxide concentrations and suspended particulates are higher than the internationally standardized level

  7. Emission parameters and thermal management of single high-power 980-nm laser diodes

    International Nuclear Information System (INIS)

    Bezotosnyi, V V; Krokhin, O N; Oleshchenko, V A; Pevtsov, V F; Popov, Yu M; Cheshev, E A

    2014-01-01

    We report emission parameters of high-power cw 980-nm laser diodes (LDs) with a stripe contact width of 100 μm. On copper heat sinks of the C-mount type, a reliable output power of 10 W is obtained at a pump current of 10 A. Using a heat flow model derived from analysis of calculated and measured overall efficiencies at pump currents up to 20 A, we examine the possibility of raising the reliable power limit of a modified high-power LD mounted on heat sinks of the F-mount type using submounts with optimised geometric parameters and high thermal conductivity. The possibility of increasing the maximum reliable cw output power to 20 W with the use of similar laser crystals is discussed. (lasers)

  8. Emission of Polycyclic Aromatic Hydrocarbons from the Exhalation Zones of Thermally Active Mine Waste Dumps

    Directory of Open Access Journals (Sweden)

    Patrycja Kuna-Gwoździewicz

    2013-01-01

    Full Text Available The article presents results of research carried out on the occurrence of polycyclic aromatic hydrocarbons (PAH in gases of exhalation zones, created on the surface of a thermally active coal mine waste dump. The oxidation and self-heating of mine waste are accompanied with the intensive emission of flue gases, including PAH group compounds. Taking into consideration the fact the hydrocarbons show strong genotoxic, mutagenic and carcinogenic properties, research was conducted to establish their content in the examined gases. The research object was a gangue dump located in Rybnik. The research was performed in 2012. In total, 24 samples of gas were collected with PUF (polyurethane foam sampling cartridges with a quartz fibre filter and an aspirator. The collected samples were analysed with the use of high performance liquid chromatography (HPLC and a fluorescence detector (FLD to evaluate the amount of PAH present.

  9. Thermal Infrared Emission Spectroscopy of Synthetic Allophane and its Potential Formation on Mars

    Science.gov (United States)

    Rampe, E. B.; Kraft, M. D.; Sharp, T. G.; Golden, D. C.; Ming, Douglas W.

    2010-01-01

    Allophane is a poorly-crystalline, hydrous aluminosilicate with variable Si/Al ratios approx.0.5-1 and a metastable precursor of clay minerals. On Earth, it forms rapidly by aqueous alteration of volcanic glass under neutral to slightly acidic conditions [1]. Based on in situ chemical measurements and the identification of alteration phases [2-4], the Martian surface is interpreted to have been chemically weathered on local to regional scales. Chemical models of altered surfaces detected by the Mars Exploration Rover Spirit in Gusev crater suggest the presence of an allophane-like alteration product [3]. Thermal infrared (TIR) spectroscopy and spectral deconvolution models are primary tools for determining the mineralogy of the Martian surface [5]. Spectral models of data from the Thermal Emission Spectrometer (TES) indicate a global compositional dichotomy, where high latitudes tend to be enriched in a high-silica material [6,7], interpreted as high-silica, K-rich volcanic glass [6,8]. However, later interpretations proposed that the high-silica material may be an alteration product (such as amorphous silica, clay minerals, or allophane) and that high latitude surfaces are chemically weathered [9-11]. A TIR spectral library of pure minerals is available for the public [12], but it does not contain allophane spectra. The identification of allophane on the Martian surface would indicate high water activity at the time of its formation and would help constrain the aqueous alteration environment [13,14]. The addition of allophane to the spectral library is necessary to address the global compositional dichotomy. In this study, we characterize a synthetic allophane by IR spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) to create an IR emission spectrum of pure allophane for the Mars science community to use in Martian spectral models.

  10. High thermal efficiency and low emission performance of a methanol reformed gas fueled engine for hybrid electric vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, K.; Nakajima, Y.; Shudo, T.; Hiruma, M. [Musahi Inst. of Tech., Tokyo (Japan); Komatsu, H.; Takagi, Y. [Nissan Motor Co., Ltd., Yokosuka (Japan)

    2000-07-01

    An internal combustion engine (ICE) operation was carried out experimentally by using the mixture of air and fuel simulating the reformed gas as the fuel. It has been found that the engine can expectedly attain ultra-low emission and high thermal efficiency, namely 35% brake thermal efficiency in the basis of the low heat value of the theoretically reformed gas or 42% in the basis of the low heat value of methanol. By using the result for the estimation of the total thermal efficiency at the end of the motor output shaft of a hybrid electric vehicle, it has been found that the total thermal efficiency of the reformed gas engine system is 34% in case of a 120% energy increment and 33% in case of a 116% energy increment with a little higher NOx emission of 60 ppm while the counterpart of the fuel cell system is 34%. When the emission level for EZEV is required, the total thermal efficiency falls to 32% in case of a 120% energy increment and 31% in case of a 116% energy increment. From the points of the reliability proved by the long history, higher specific power and low cost, the internal combustion engine system with the thermal efficiency almost equal to that of the fuel cell (FC) system is further more practical when methanol is used as the fuel. (orig.)

  11. Thermal analysis and infrared emission spectroscopic study of halloysite-potassium acetate intercalation compound

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Liu, Qinfu [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); Yang, Jing [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zhang, Jinshan [School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Frost, Ray L., E-mail: r.frost@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

    2010-11-20

    The thermal decomposition of halloysite-potassium acetate intercalation compound was investigated by thermogravimetric analysis and infrared emission spectroscopy. The X-ray diffraction patterns indicated that intercalation of potassium acetate into halloysite caused an increase of the basal spacing from 1.00 to 1.41 nm. The thermogravimetry results show that the mass losses of intercalation the compound occur in main three main steps, which correspond to (a) the loss of adsorbed water, (b) the loss of coordination water and (c) the loss of potassium acetate and dehydroxylation. The temperature of dehydroxylation and dehydration of halloysite is decreased about 100 {sup o}C. The infrared emission spectra clearly show the decomposition and dehydroxylation of the halloysite intercalation compound when the temperature is raised. The dehydration of the intercalation compound is followed by the loss of intensity of the stretching vibration bands at region 3600-3200 cm{sup -1}. Dehydroxylation is followed by the decrease in intensity in the bands between 3695 and 3620 cm{sup -1}. Dehydration was completed by 300 {sup o}C and partial dehydroxylation by 350 {sup o}C. The inner hydroxyl group remained until around 500 {sup o}C.

  12. PHOTOMETRIC VARIABILITY OF THE DISK-INTEGRATED THERMAL EMISSION OF THE EARTH

    International Nuclear Information System (INIS)

    Gómez-Leal, I.; Selsis, F.; Pallé, E.

    2012-01-01

    Here we present an analysis of the global-integrated mid-infrared emission flux of the Earth based on data derived from satellite measurements. We have studied the photometric annual, seasonal, and rotational variability of the thermal emission of the Earth to determine which properties can be inferred from the point-like signal. We find that the analysis of the time series allows us to determine the 24 hr rotational period of the planet for most observing geometries, due to large warm and cold areas, identified with geographic features, which appear consecutively in the observer's planetary view. However, the effects of global-scale meteorology can effectively mask the rotation for several days at a time. We also find that orbital time series exhibit a seasonal modulation, whose amplitude depends strongly on the latitude of the observer but weakly on its ecliptic longitude. As no systematic difference of brightness temperature is found between the dayside and the nightside, the phase variations of the Earth in the infrared range are negligible. Finally, we also conclude that the phase variation of a spatially unresolved Earth-Moon system is dominated by the lunar signal.

  13. Thermal effects on vehicle emission dispersion in an urban street canyon

    Energy Technology Data Exchange (ETDEWEB)

    Xiaomin Xie; Zhen Huang; Jiasong Wang; Zheng Xie [Shanghai Jiao Tong Univ., School of Mechanical Engineering, Shanghai (China)

    2005-05-15

    The impact of the thermal effects on vehicle emission dispersion within street canyons is examined. The results show that heating from building wall surfaces and horizontal surfaces lead to strong buoyancy forces close to surfaces receiving direct solar radiation. This thermally induced flow is combined with mechanically induced flows formed in the canyon where there is no solar heating, and affects the transport of pollutants from the canyon to the layer aloft. The relative influence of each of these effects can be estimates by Gr/Re{sup 2}. When the windward wall is warmer than the air, an upward buoyancy flux opposes the downward advection flux along the wall; if Gr/Re{sup 2} > 2, the flow structure is divided into two counter-rotating cells, and pollutants are accumulated on the windward side of the canyon. When the horizontal surface is heated, and Gr/Re{sup 2} > 4, the flow structure is divided into two counter-rotating cells by upward buoyancy flux. Pollutants are accumulated at the windward side of the canyon. When the leeward side is heated, the buoyancy flux adds to the upward advection flux along the wall strengthening the original vortex and pollutant effects of transport compared to the isothermal case. (Author)

  14. Status of electron temperature and density measurement with beam emission spectroscopy on thermal helium at TEXTOR

    International Nuclear Information System (INIS)

    Schmitz, O; Schweer, B; Pospieszczyk, A; Lehnen, M; Samm, U; Unterberg, B; Beigman, I L; Vainshtein, L A; Kantor, M; Xu, Y; Krychowiak, M

    2008-01-01

    Beam emission spectroscopy on thermal helium is used at the TEXTOR tokamak as a reliable method to obtain radial profiles of electron temperature T e (r, t) and electron density n e (r, t). In this paper the experimental realization of this method at TEXTOR and the status of the atomic physics employed as well as the major factors for the measurement's accuracy are evaluated. On the experimental side, the hardware specifications are described and the impact of the beam atoms on the local plasma parameters is shown to be negligible. On the modeling side the collisional-radiative model (CRM) applied to infer n e and T e from the measured He line intensities is evaluated. The role of proton and deuteron collisions and of charge exchange processes is studied with a new CRM and the impact of these so far neglected processes appears to be of minor importance. Direct comparison to Thomson scattering and fast triple probe data showed that for high densities n e > 3.5 x 10 19 m -3 the T e values deduced with the established CRM are too low. However, the new atomic data set implemented in the new CRM leads in general to higher T e values. This allows us to specify the range of reliable application of BES on thermal helium to a range of 2.0 x 10 18 e 19 m -3 and 10 eV e < 250 eV which can be extended by routine application of the new CRM.

  15. Airborne emissions of carcinogens and respiratory sensitizers during thermal processing of plastics.

    Science.gov (United States)

    Unwin, John; Coldwell, Matthew R; Keen, Chris; McAlinden, John J

    2013-04-01

    Thermoplastics may contain a wide range of additives and free monomers, which themselves may be hazardous substances. Laboratory studies have shown that the thermal decomposition products of common plastics can include a number of carcinogens and respiratory sensitizers, but very little information exists on the airborne contaminants generated during actual industrial processing. The aim of this work was to identify airborne emissions during thermal processing of plastics in real-life, practical applications. Static air sampling was conducted at 10 industrial premises carrying out compounding or a range of processes such as extrusion, blown film manufacture, vacuum thermoforming, injection moulding, blow moulding, and hot wire cutting. Plastics being processed included polyvinyl chloride, polythene, polypropylene, polyethylene terephthalate, and acrylonitrile-butadiene-styrene. At each site, static sampling for a wide range of contaminants was carried out at locations immediately adjacent to the prominent fume-generating processes. The monitoring data indicated the presence of few carcinogens at extremely low concentrations, all less than 1% of their respective WEL (Workplace Exposure Limit). No respiratory sensitizers were detected at any sites. The low levels of process-related fume detected show that the control strategies, which employed mainly forced mechanical general ventilation and good process temperature control, were adequate to control the risks associated with exposure to process-related fume. This substantiates the advice given in the Health and Safety Executive's information sheet No 13, 'Controlling Fume During Plastics Processing', and its broad applicability in plastics processing in general.

  16. Evidence of hot spot formation on carbon limiters due to thermal electron emission

    International Nuclear Information System (INIS)

    Philipps, V.; Samm, U.; Tokar, M.Z.; Unterberg, B.; Pospieszczyk, A.; Schweer, B.

    1993-01-01

    Carbon test limiters have been exposed in TEXTOR to high heat loads up to about 30 MW/m 2 . The evolutions of the surface temperature distribution and of the carbon release have been observed by means of local diagnostics. A sudden acceleration of the rise of the surface temperature has been found at a critical temperature of approx. 2400 deg. C. The increase of the rate of the temperature rise is consistent with an enhancement of the power loading by a factor of 2.5-3. Following the temperature jump (hot spot), a quasi-equilibrium temperature establishes at approx. 2700 deg. C. The development of the hot spot is explained by an increase of the local power loading to the breakdown of the sheath potential by thermal emission of electrons from the carbon surface. Simultaneously with the appearance of the hot spot, the carbon release from the surface increases sharply. This increase can be explained by normal thermal sublimation. Sublimation cooling contributes to the establishment of the quasi-equilibrium temperature at about 2700 deg. C. (author). 16 refs, 10 figs

  17. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

    Science.gov (United States)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  18. A New GPU-Enabled MODTRAN Thermal Model for the PLUME TRACKER Volcanic Emission Analysis Toolkit

    Science.gov (United States)

    Acharya, P. K.; Berk, A.; Guiang, C.; Kennett, R.; Perkins, T.; Realmuto, V. J.

    2013-12-01

    Real-time quantification of volcanic gaseous and particulate releases is important for (1) recognizing rapid increases in SO2 gaseous emissions which may signal an impending eruption; (2) characterizing ash clouds to enable safe and efficient commercial aviation; and (3) quantifying the impact of volcanic aerosols on climate forcing. The Jet Propulsion Laboratory (JPL) has developed state-of-the-art algorithms, embedded in their analyst-driven Plume Tracker toolkit, for performing SO2, NH3, and CH4 retrievals from remotely sensed multi-spectral Thermal InfraRed spectral imagery. While Plume Tracker provides accurate results, it typically requires extensive analyst time. A major bottleneck in this processing is the relatively slow but accurate FORTRAN-based MODTRAN atmospheric and plume radiance model, developed by Spectral Sciences, Inc. (SSI). To overcome this bottleneck, SSI in collaboration with JPL, is porting these slow thermal radiance algorithms onto massively parallel, relatively inexpensive and commercially-available GPUs. This paper discusses SSI's efforts to accelerate the MODTRAN thermal emission algorithms used by Plume Tracker. Specifically, we are developing a GPU implementation of the Curtis-Godson averaging and the Voigt in-band transmittances from near line center molecular absorption, which comprise the major computational bottleneck. The transmittance calculations were decomposed into separate functions, individually implemented as GPU kernels, and tested for accuracy and performance relative to the original CPU code. Speedup factors of 14 to 30× were realized for individual processing components on an NVIDIA GeForce GTX 295 graphics card with no loss of accuracy. Due to the separate host (CPU) and device (GPU) memory spaces, a redesign of the MODTRAN architecture was required to ensure efficient data transfer between host and device, and to facilitate high parallel throughput. Currently, we are incorporating the separate GPU kernels into a

  19. Flame retardancy and thermal properties of epoxy acrylate resin/alpha-zirconium phosphate nanocomposites used for UV-curing flame retardant films

    International Nuclear Information System (INIS)

    Xing Weiyi; Jie Ganxin; Song Lei; Wang Xin; Lv Xiaoqi; Hu Yuan

    2011-01-01

    This paper reported the UV-curing flame retardant film, which consisted of epoxy acrylate resin (EA) used as an oligomer, tri(acryloyloxyethyl) phosphate (TAEP) and triglycidyl isocyanurate acrylate (TGICA) used as flame retardant (FR). The flame retardancy and thermal properties of films were reinforced by using alpha-zirconium phosphate (α-Zr (HPO 4 ) 2 H 2 O, α-ZrP). The morphology of nanocomposite film was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the organophilic α-ZrP (OZrP) layers were dispersed well in epoxy acrylate resin. Microscale Combustion Calorimeter (MCC), thermogravimetric analysis (TGA) and thermogravimetric analysis/infrared spectrometry (TGA-IR) were used to characterize the flame retardant property and thermal stability. It was found that the incorporation of TAEP and TGICA can reduce the flammability of EA. Moreover, further reductions were observed due to the addition of OZrP. The char residue for systems with or without OZrP was also explored by scanning electron microscopy (SEM).

  20. Non-thermal emission from young supernova remnants: Implications on cosmic ray acceleration

    Science.gov (United States)

    Araya-Arguedas, Miguel A.

    For a long time, supernova remnants have been thought to constitute the main source of galactic cosmic rays. Plausible mechanisms have been proposed through which these objects would be able to transfer some of their energy to charged particles. Detailed studies of SNRs, particularly allowed by the spectral and spatial resolution obtained with telescopes such as the Chandra X-Ray Observatory , have permitted us to understand some of the properties of high-energy particles within these objects and their interactions with their environment. In the first part of this work, the basic concepts of particle acceleration in SNRs are outlined, and the main observational tools available today for studying high-energy phenomena in astrophysics are mentioned briefly. In the second part, a study of non-thermal emission from the young SNR Cassiopeia A is presented. Through the use of a very deep one million-second Chandra observation of this remnant, the spectral evolution across non-thermal filaments near the forward shock was studied. A consistent hardening of the spectrum towards the exterior of the remnant was found and explained via a model developed that takes into account particle diffusion, plasma advection and radiation losses. The role of particle diffusion was studied and its effect on the photon spectral index quantified. In the model, the diffusion is included as a fraction of Bohm-type diffusion, which is consistent with the data. The model also allowed an estimation of the electron distribution, the magnetic field and its orientation, as well as the level of magnetic turbulence. In the third part, a multi-wavelength study of two young SNRs is presented. Multi-wavelength modeling of spectral energy distributions (SED) may hold the key to disentangle the nature and content of cosmic rays within these objects. The first model shown presents state of the art measurements gathered for Cassiopeia A, and the modeling is based partly on the results presented in the second

  1. A comparative study of field-emission from different one dimensional carbon nanostructures synthesized via thermal CVD system

    International Nuclear Information System (INIS)

    Jha, A.; Banerjee, D.; Chattopadhyay, K.K.

    2011-01-01

    Different one dimensional (1D) carbon nanostructures, such as carbon nanonoodles (CNNs), carbon nanospikes (CNSs) and carbon nanotubes (CNTs) have been synthesized via thermal chemical vapour deposition (TCVD) technique. The different 1D morphologies were synthesized by varying the substrate material and the deposition conditions. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). FESEM and TEM images showed that the diameters of the CNNs and CNTs were ∼40 nm while the diameters of the CNSs were around 100 nm. Field emission studies of the as-prepared samples showed that CNSs to be a better field emitter than CNNs, whereas CNTs are the best among the three producing large emission current. The variation of field emission properties with inter-electrode distance has been studied in detail. Also the time dependent field emission studies of all the nanostructures have been carried out.

  2. Biological Particle Emissions From a South-East Asian Tropical Rainforest Using a Real- Time Dual Channel UV Fluorescence Bio-Aerosol Spectrometer

    Science.gov (United States)

    Gabey, A.; Coe, H.; Gallagher, M.; McFiggans, G.; Kaye, P.; Stanley, W.; Foot, V.

    2008-12-01

    and net emission for all fungal spores is ~1 μ g m-3 and ~50 Tg yr-1. These calculations demonstrate the potential importance of PBA, and in particular fungal spores, for global budgets of organic aerosols, particularly in tropical regions, however uncertainties are extremely large, ranging from 50 - 1000 Tg yr- 1. In this study we use the WIBS-3: a low-cost portable single-particle dual-channel UV fluorescence spectrometer (Kaye et al., 2008) to investigate the dynamics of PBA in real-time within and above a tropical forest of 50 m height in Borneo, Malaysia, to estimate net PBA emissions. Different circadian cycles were observed for bio and non-bio aerosol sources and the factors controlling bioaerosol emissions will be discussed in detail.

  3. Paragenesis of thermal denudation with gas-emission crater and lake formation, Yamal Peninsula, Russia

    Science.gov (United States)

    Babkina, Elena; Khomutov, Artem; Leibman, Marina; Dvornikov, Yury; Kizyakov, Alexander; Babkin, Evgeny

    2017-04-01

    Gas-emission craters (GECs) found in the North of West Siberia in 2014 occur in an area of wide tabular ground ice (TGI) distribution. TGI observed in the GEC walls also provokes thermal denudation: a complex of processes responsible for formation of thermocirques (TCs). TCs are semi-circle shaped depressions resulting from TGI thaw and removal of detached material downslope. Shores of many lakes are terraced and have ancient to recent traces of thermal denudation activity. TCs are numerous in the GEC area giving reason to assume that GEC, TGI, TC, and lakes are interrelated. First found Yamal crater (GEC-1) expanded from initial 18 m wide deep hole in 2013 to an irregularly-shaped lake up to 85 meters wide in 2016. Expansion of the GEC was controlled by TGI thaw. This can be considered in terms of thermal denudation and analyzed on the basis of TC study in the adjacent area. In summer 2014 and 2015 (the lifetime of the GEC-1) its wall retreat covered the area of 1730 square meters, which gives 865 square meters per year. In 2016, which was the warmest for the period of observation at weather station Marre-Sale, retreat area increased to 2200 square meters per year. TC, which exposed TGI similar to that in the walls of GEC-1, is observed on the nearest lakeshore. TC activation probably started in 2012 as elsewhere on Yamal. In 2015 its area according to GPS survey reached 4400 square meters (a four-year average 1100 square meters). Since September 2015 and till October 2016 its area expanded by 2600 square meters, thus increased by 59%, and more than twice compared to previous annual average. Lake adjacent to GEC-1 in 2016 was separated from crater edge by only a 13 meter wide isthmus, most likely both GEC-1 lake and adjacent lake merge in few years. Therefore, single basis of erosion for thermal denudation appear. After lakes merge, it would become hard to determine what the initial process for the lake formation was if not for the occasional discovery of the GEC

  4. IR, UV-Vis, magnetic and thermal characterization of chelates of some catecholamines and 4-aminoantipyrine with Fe(III) and Cu(II)

    Science.gov (United States)

    Mohamed, Gehad G.; Zayed, M. A.; El-Dien, F. A. Nour; El-Nahas, Reham G.

    2004-07-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. α-Methyldopa (α-MD) in tablets is used in medication of hypertension. The Fe(III) and Cu(II) chelates with coupled products of adrenaline hydrogen tartarate (AHT), levodopa (LD), α-MD and carbidopa (CD) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical methods like IR, magnetic and UV-Vis spectra are used to investigate the structure of these chelates. Fe(III) form 1:2 (M:catecholamines) chelates while Cu(II) form 1:1 chelates. Catecholamines behave as a bidentate mono- or dibasic ligands in binding to the metal ions. IR spectra show that the catecholamines are coordinated to the metal ions in a bidentate manner with O,O donor sites of the phenolic - OH. Magnetic moment measurements reveal the presence of Fe(III) chelates in octahedral geometry while the Cu(II) chelates are square planar. The thermal decomposition of Fe(III) and Cu(II) complexes is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The water molecules are removed in the first step followed immediately by decomposition of the ligand molecules. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  5. Enhanced orange-red emission by using Mo codoped in Ba2CaWO6: Eu3+, Li+ phosphor under near UV excitation

    International Nuclear Information System (INIS)

    Sun, Xiaoyuan; Hao, Zhendong; Li, Chunjie; He, Xiaoguang; Qi, Haiyan; Yu, Lijun; Luo, Yongshi; Zhang, Jiahua; Gao, Jiwei; Zhong, Ruixia

    2013-01-01

    The orange-red emitting phosphors Ba 2 Ca 0.9 Mo x W 1−x O 6 :Eu 3+ 0.05 , Li + 0.05 (x=0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.5, 0.75, and 1.0) and Ba 2 Ca 1−2y Mo 0.2 W 0.8 O 6 :Eu 3+ y , Li + y (y=0.03, 0.05, 0.07, 0.1, and 0.15) were synthesized. The crystalline structure and photoluminescence properties of these phosphors were described. The strong orange-red emission of Eu 3+ ( 5 D 0 — 7 F 1 transition) at around 593 nm was observed. Addition of Mo strongly enhances the charge transfer band absorption in the near ultraviolet region that corresponds to near ultraviolet white light emitting diode. The dependence of photoluminescence intensities on Eu 3+ concentrations with optimal Mo concentration under 400 nm excitation was studied. The phosphor is considered to be a promising orange-red emitting phosphor for near ultraviolet GaN-based white light emitting diode. - Highlights: ► The samples form solid solutions when Mo is added into Ba 2 CaWO 6 : Eu 3+ , Li + phosphors. ► Addition of Mo in Ba 2 CaWO 6 : Eu 3+ , Li + shifts the PLE spectra maximum from UV region to near UV region. ► In Ba 2 CaMo x W 1−x O 6 :Eu 3+ , Li + , the most efficient concentrations occur at 0.1 and 0.2 for Eu and Mo.

  6. Correlated X-ray/UV/optical emission and short-term variability in a Seyfert 1 galaxy NGC 4593

    Science.gov (United States)

    Pal, Main; Naik, Sachindra

    2018-03-01

    We present a detailed multifrequency analysis of an intense monitoring programme of Seyfert 1 galaxy NGC 4593 over a duration of nearly for a month with Swift observatory. We used 185 pointings to study the variability in six ultraviolet/optical and two soft (0.3-1.5 keV) and hard X-ray (1.5-10 keV) bands. The amplitude of the observed variability is found to decrease from high energy to low energy (X-ray to optical) bands. Count-count plots of ultraviolet/optical bands with hard X-rays clearly suggest the presence of a mixture of two major components: (i) highly variable component such as hard X-ray emission, and (ii) slowly varying disc-like component. The variations observed in the ultraviolet/optical emission are strongly correlated with the hard X-ray band. Cross-correlation analysis provides the lags for the longer wavelengths compared to the hard X-rays. Such lags clearly suggest that the changes in the ultraviolet/optical bands follow the variations in the hard X-ray band. This implies that the observed variation in longer wavelengths is due to X-ray reprocessing. Though, the measured lag spectrum (lag versus wavelength) is well described by λ4/3 as expected from the standard disc model, the observed lags are found to be longer than the predicted values from standard disc model. This implies that the actual size of the disc of NGC 4593 is larger than the estimated size of standard thin disc as reported in active galactic nuclei such as NGC 5548 and Fairall 9.

  7. An Optimization Scheduling Model for Wind Power and Thermal Power with Energy Storage System considering Carbon Emission Trading

    Directory of Open Access Journals (Sweden)

    Huan-huan Li

    2015-01-01

    Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.

  8. Metallic layer-by-layer photonic crystals for linearly-polarized thermal emission and thermophotovoltaic device including same

    Science.gov (United States)

    Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P.

    2016-07-26

    Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 .mu.m, as well as high emissivity up to 0.65 at a wavelength of 3.7 .mu.m. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization.

  9. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  10. First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

    Energy Technology Data Exchange (ETDEWEB)

    Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen [Department of Astronomy, California Institute of Technology, 1200 E. California Ave., Pasadena, CA 91125 (United States); Güdel, Manuel [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Rupen, Michael, E-mail: jrv@astro.caltech.edu [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

    2014-06-20

    We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

  11. First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

    International Nuclear Information System (INIS)

    Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen; Güdel, Manuel; Rupen, Michael

    2014-01-01

    We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

  12. The iterative thermal emission method: A more implicit modification of IMC

    Energy Technology Data Exchange (ETDEWEB)

    Long, A.R., E-mail: arlong.ne@tamu.edu [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77843 (United States); Gentile, N.A. [Lawrence Livermore National Laboratory, L-38, P.O. Box 808, Livermore, CA 94550 (United States); Palmer, T.S. [Nuclear Engineering and Radiation Health Physics, Oregon State University, 100 Radiation Center, Corvallis, OR 97333 (United States)

    2014-11-15

    For over 40 years, the Implicit Monte Carlo (IMC) method has been used to solve challenging problems in thermal radiative transfer. These problems typically contain regions that are optically thick and diffusive, as a consequence of the high degree of “pseudo-scattering” introduced to model the absorption and reemission of photons from a tightly-coupled, radiating material. IMC has several well-known features that could be improved: a) it can be prohibitively computationally expensive, b) it introduces statistical noise into the material and radiation temperatures, which may be problematic in multiphysics simulations, and c) under certain conditions, solutions can be nonphysical, in that they violate a maximum principle, where IMC-calculated temperatures can be greater than the maximum temperature used to drive the problem. We have developed a variant of IMC called iterative thermal emission IMC, which is designed to have a reduced parameter space in which the maximum principle is violated. ITE IMC is a more implicit version of IMC in that it uses the information obtained from a series of IMC photon histories to improve the estimate for the end of time step material temperature during a time step. A better estimate of the end of time step material temperature allows for a more implicit estimate of other temperature-dependent quantities: opacity, heat capacity, Fleck factor (probability that a photon absorbed during a time step is not reemitted) and the Planckian emission source. We have verified the ITE IMC method against 0-D and 1-D analytic solutions and problems from the literature. These results are compared with traditional IMC. We perform an infinite medium stability analysis of ITE IMC and show that it is slightly more numerically stable than traditional IMC. We find that significantly larger time steps can be used with ITE IMC without violating the maximum principle, especially in problems with non-linear material properties. The ITE IMC method does

  13. The iterative thermal emission method: A more implicit modification of IMC

    International Nuclear Information System (INIS)

    Long, A.R.; Gentile, N.A.; Palmer, T.S.

    2014-01-01

    For over 40 years, the Implicit Monte Carlo (IMC) method has been used to solve challenging problems in thermal radiative transfer. These problems typically contain regions that are optically thick and diffusive, as a consequence of the high degree of “pseudo-scattering” introduced to model the absorption and reemission of photons from a tightly-coupled, radiating material. IMC has several well-known features that could be improved: a) it can be prohibitively computationally expensive, b) it introduces statistical noise into the material and radiation temperatures, which may be problematic in multiphysics simulations, and c) under certain conditions, solutions can be nonphysical, in that they violate a maximum principle, where IMC-calculated temperatures can be greater than the maximum temperature used to drive the problem. We have developed a variant of IMC called iterative thermal emission IMC, which is designed to have a reduced parameter space in which the maximum principle is violated. ITE IMC is a more implicit version of IMC in that it uses the information obtained from a series of IMC photon histories to improve the estimate for the end of time step material temperature during a time step. A better estimate of the end of time step material temperature allows for a more implicit estimate of other temperature-dependent quantities: opacity, heat capacity, Fleck factor (probability that a photon absorbed during a time step is not reemitted) and the Planckian emission source. We have verified the ITE IMC method against 0-D and 1-D analytic solutions and problems from the literature. These results are compared with traditional IMC. We perform an infinite medium stability analysis of ITE IMC and show that it is slightly more numerically stable than traditional IMC. We find that significantly larger time steps can be used with ITE IMC without violating the maximum principle, especially in problems with non-linear material properties. The ITE IMC method does

  14. The iterative thermal emission method: A more implicit modification of IMC

    Science.gov (United States)

    Long, A. R.; Gentile, N. A.; Palmer, T. S.

    2014-11-01

    For over 40 years, the Implicit Monte Carlo (IMC) method has been used to solve challenging problems in thermal radiative transfer. These problems typically contain regions that are optically thick and diffusive, as a consequence of the high degree of ;pseudo-scattering; introduced to model the absorption and reemission of photons from a tightly-coupled, radiating material. IMC has several well-known features that could be improved: a) it can be prohibitively computationally expensive, b) it introduces statistical noise into the material and radiation temperatures, which may be problematic in multiphysics simulations, and c) under certain conditions, solutions can be nonphysical, in that they violate a maximum principle, where IMC-calculated temperatures can be greater than the maximum temperature used to drive the problem. We have developed a variant of IMC called iterative thermal emission IMC, which is designed to have a reduced parameter space in which the maximum principle is violated. ITE IMC is a more implicit version of IMC in that it uses the information obtained from a series of IMC photon histories to improve the estimate for the end of time step material temperature during a time step. A better estimate of the end of time step material temperature allows for a more implicit estimate of other temperature-dependent quantities: opacity, heat capacity, Fleck factor (probability that a photon absorbed during a time step is not reemitted) and the Planckian emission source. We have verified the ITE IMC method against 0-D and 1-D analytic solutions and problems from the literature. These results are compared with traditional IMC. We perform an infinite medium stability analysis of ITE IMC and show that it is slightly more numerically stable than traditional IMC. We find that significantly larger time steps can be used with ITE IMC without violating the maximum principle, especially in problems with non-linear material properties. The ITE IMC method does however

  15. THE LOCAL DUST FOREGROUNDS IN THE MICROWAVE SKY. I. THERMAL EMISSION SPECTRA

    International Nuclear Information System (INIS)

    Dikarev, Valeri; Preuss, Oliver; Solanki, Sami; Krueger, Harald; Krivov, Alexander

    2009-01-01

    Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the quadrupole moment of the CMB fluctuations is remarkably low, and the quadrupole and octopole moments are aligned mutually and with the geometry of the solar system. It has been suggested in the literature that microwave sky pollution by an unidentified dust cloud in the vicinity of the solar system may be the cause for these anomalies. In this paper, we simulate the thermal emission by clouds of spherical homogeneous particles of several materials. Spectral constraints from the WMAP multi-wavelength data and earlier infrared observations on the hypothetical dust cloud are used to determine the dust cloud's physical characteristics. In order for its emissivity to demonstrate a flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14 mm), and to be invisible in the infrared light, its particles must be macroscopic. Silicate spheres of several millimeters in size and carbonaceous particles an order of magnitude smaller will suffice. According to our estimates of the abundance of such particles in the zodiacal cloud and trans-Neptunian belt, yielding the optical depths of the order of 10 -7 for each cloud, the solar system dust can well contribute 10 μK (within an order of magnitude) in the microwaves. This is not only intriguingly close to the magnitude of the anomalies (about 30 μK), but also alarmingly above the presently believed magnitude of systematic biases of the WMAP results (below 5 μK) and, to an even greater degree, of the future missions with higher sensitivities, e.g., Planck.

  16. Thermal and UV stability of β-carotene dissolved in peppermint oil microemulsified by sunflower lecithin and Tween 20 blend.

    Science.gov (United States)

    Chen, Huaiqiong; Zhong, Qixin

    2015-05-01

    Microemulsions are suitable for simultaneous delivery of flavour oils and lipophilic bioactive compounds in transparent beverages. In the present study, the feasibility of delivering β-carotene in microemulsions formulated with peppermint oil and a blend of Tween® 20 and various amounts of sunflower lecithin was investigated. The poorly water- and oil-soluble β-carotene was dissolved in the transparent microemulsions that had particles smaller than 10nm and were stable during ambient storage for 65 d. The inclusion of β-carotene did not change the flow-behaviour and Newtonian viscosity. The degradation of β-carotene in microemulsions during ambient storage, ultraviolet radiation, and thermal treatments at 60 and 80 °C followed first order kinetics and was greatly suppressed when compared to the solution control. The antioxidant potential of peppermint oil and a greater content of lecithin in microemulsions enabled the better protection of β-carotene. The studied microemulsions may find various applications in manufacturing transparent beverages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

    Directory of Open Access Journals (Sweden)

    T. Karthikeya Sharma

    2015-11-01

    Full Text Available Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE. This paper investigates the effects of using argon (Ar gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied.

  18. FINDING ROCKY ASTEROIDS AROUND WHITE DWARFS BY THEIR PERIODIC THERMAL EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Henry W. [Harvard College, Cambridge, MA 02138 (United States); Loeb, Abraham, E-mail: henrylin@college.harvard.edu [Harvard Astronomy Department, Harvard University, Cambridge, MA 02138 (United States)

    2014-10-01

    Since white dwarfs (WDs) are small, the contrast between the thermal emission of an orbiting object and a WD is dramatically enhanced compared to a main-sequence host. Furthermore, rocky objects much smaller than the moon have no atmospheres and are tidally locked to the WD. We show that this leads to temperature contrasts between their day and night side of the order of unity that should lead to temporal variations in infrared flux over an orbital period of ∼0.2 to ∼2 days. Ground-based telescopes could detect objects with a mass as small as 1% of the lunar mass M{sub L} around Sirius B with a few hours of exposure. The James Webb Space Telescope may be able to detect objects as small as 10{sup –3} M{sub L} around most nearby WDs. The tightest constraints will typically be placed on 12,000 K WDs, whose Roche zone coincides with the dust sublimation zone. Constraining the abundance of minor planets around WDs as a function of their surface temperatures (and therefore age) provides a novel probe for the physics of planetary formation.

  19. Emission of Lyman α radiation in H2 + H*(2s) collisions at thermal energies

    International Nuclear Information System (INIS)

    Stern, B.

    1991-01-01

    A previously-published study of the thermal-energy collision between H 2 and metastable H*(2s), which could lead to the emission of Lyman α radiation, is reconsidered to take into account possible polarization effects. The total was function of the system is expanded in terms of the molecular states of the intermediate complex H 2 * , which constitute the minimal basis of the four adiabatic states dissociating into H 2 + H*(n=2) where they are normally degenerate in energy. The results of the calculation show the existence, between three of those states, of average values of the separation distance R (R ≅ 10 atomic units) of long range (ΔR ≅ 2 au) electronic interactions which depend on the geometric form of the H 2 * molecule. From the molecular data the hypothesis of no longer considering H 2 with H*(2s) as a rigid rotator is postulated and justified, after a purely quantum mechanical treatment of the radial equations. The mean ratio of the (oscillating) polarization angular differential cross sections tot he elastic ones is found important (> ∼ 1/10). The inelastic phenomena are anticipated to be more marked in the ortho than in the para hydrogen at a low collision energy (75 meV). (15 refs., 2 tabs., 9 figs.)

  20. Analysis of Saturn's Thermal Emission at 2.2-cm Wavelength: Spatial Distribution of Ammonia Vapor

    Science.gov (United States)

    Laraia, A. L.; Ingersoll, A. P.; Janssen, Michael A.; Gulkis, Samuel; Oyafuso, Fabiano A.; Allison, Michael D.

    2013-01-01

    This work focuses on determining the latitudinal structure of ammonia vapor in Saturn's cloud layer near 1.5 bars using the brightness temperature maps derived from the Cassini RADAR (Elachi et al., 2004) instrument, which works in a passive mode to measure thermal emission from Saturn at 2.2-cm wavelength. We perform an analysis of five brightness temperature maps that span epochs from 2005 to 2011, which are presented in a companion paper by Janssen et al. (2013a, this issue). The brightness temperature maps are representative of the spatial distribution of ammonia vapor, since ammonia gas is the only effective opacity source in Saturn's atmosphere at 2.2-cm wavelength. Relatively high brightness temperatures indicate relatively low ammonia relative humidity (RH), and vice versa. We compare the observed brightness temperatures to brightness temperatures computed using the Juno atmospheric microwave radiative transfer (JAMRT) program which includes both the means to calculate a tropospheric atmosphere model for Saturn and the means to carry out radiative transfer calculations at microwave frequencies. The reference atmosphere to which we compare has a 3x solar deep mixing ratio of ammonia (we use 1.352x10(exp -4) for the solar mixing ratio of ammonia vapor relative to H2; see Atreya, 2010) and is fully saturated above its cloud base. The maps are comprised of residual brightness temperatures-observed brightness temperature minus the model brightness temperature of the saturated atmosphere.

  1. Development of a thermally stimulated exoelectron emission (TSEE) system for dosimetric applications

    International Nuclear Information System (INIS)

    Rocha, Felicia del Gallo

    1997-01-01

    A thermally stimulated exoelectron emission measuring system (TSEE) with a counting (reader) and a heating system was designed, constructed and tested for the dosimetry of weakly penetrating radiations, such as alpha and beta particles and low energy X rays. The counting system consists of a 271 windowless gas-flow proportional counter, while the heating system is composed by a temperature programmer that provides linear heating of the samples. The characterization of the proportional counter was done, as well as the tests to verify the performance of the counting system with reference TSEE materials, such as beryllium oxide (BeO) and magnesium oxide (MgO) single crystals. The dosimetric characteristics of some materials as pure calcium sulphate (CaS0 4 ) sintered pellets and with 10% of graphite in its composition, lithium fluoride doped with magnesium, copper and phosphor (LiF:Mg,Cu,P), lithium fluoride (LiF) thin films on aluminum and stainless steel substrates and BeO on graphite substrates were studied. As an application, the feasibility of the use of pure calcium sulphate sintered pellets and others with 10% of graphite in area monitoring of an electron accelerator with variable energy was studied. The obtained results show the usefulness of this system in the dosimetry of weakly penetrating radiations. (author)

  2. The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

    Science.gov (United States)

    Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

    2014-01-01

    We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

  3. Radio Thermal Emission from Pluto and Charon during the New Horizons Encounter

    Science.gov (United States)

    Bird, Michael; Linscott, Ivan; Hinson, David; Tyler, G. L.; Strobel, Darrell F.; New Horizons Science Team

    2017-10-01

    As part of the New Horizons Radio-Science Experiment REX, radio thermal emission from Pluto and Charon (wavelength: 4.2 cm) was observed during the encounter on 14 July 2015. The primary REX measurement, a determination of the atmospheric height profile from the surface up to about 100 km, was conducted during an uplink radio occultation at both ingress and egress (Hinson et al., Icarus 290, 96-111, 2017). During the interval between ingress and egress, when the Earth and the REX uplink signals were occulted by the Pluto disk, the spacecraft antenna continued to point toward Earth and thus scanned diametrically across the Pluto nightside. The average diameter of the HGA 3 dB beam was ≈1100 km at the surface during this opportunity, thereby providing crudely resolved measurements of the radio brightness temperature across Pluto. The best resolution for the REX radiometry observations occurred shortly after closest approach, when the HGA was scanned twice across Pluto. These observations will be reported elsewhere (Linscott et al., Icarus, submitted, 2017). In addition to the resolved observations, full disk brightness temperature measurements of both bodies were performed during the approach (dayside) and departure (nightside) phases of the encounter. We present the results of these observations and provide a preliminary interpretation of the measured brightness temperatures.

  4. Excitation wavelength dependent photoluminescence emission behavior, UV induced photoluminescence enhancement and optical gap tuning of Zn0.45Cd0.55S nanoparticles for optoelectronic applications

    Science.gov (United States)

    Osman, M. A.; Abd-Elrahim, A. G.

    2018-03-01

    In the present study, we investigate the excitation wavelength (λex) dependent photoluminescence (PL) behavior in Zn0.45Cd0.55S nanoparticles. The deconvoluted PL emission bands for nanopowders and nanocolloids reveal noticeable spectral blue shift with decreasing λex accompanied by intensity enhancement. This unusual behavior is explained in terms of selective particle size distribution in nanostructures, advancing of fast ionization process at short λex; and solvation process in polar solvent. In addition, we attributed the UV-induced PL intensity enhancement and blue shift of the optical gap to the reduction in particle size by photo-corrosion process associated with the improvement in the quantum size effect; surface modification due to cross-linkage improvement of capping molecules at NPs surface; the creation of new radiative centers and the formation of photo-passivation layers from ZnSO4 and CdSO4, and photo-enhanced oxygen adsorption on Zn0.45Cd0.55S nanoparticles surface.

  5. Deconvolution of Thermal Emissivity Spectra of Mercury to their Endmember Counterparts measured in Simulated Mercury Surface Conditions

    Science.gov (United States)

    Varatharajan, I.; D'Amore, M.; Maturilli, A.; Helbert, J.; Hiesinger, H.

    2017-12-01

    The Mercury Radiometer and Thermal Imaging Spectrometer (MERTIS) payload of ESA/JAXA Bepicolombo mission to Mercury will map the thermal emissivity at wavelength range of 7-14 μm and spatial resolution of 500 m/pixel [1]. Mercury was also imaged at the same wavelength range using the Boston University's Mid-Infrared Spectrometer and Imager (MIRSI) mounted on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii with the minimum spatial coverage of 400-600km/spectra which blends all rocks, minerals, and soil types [2]. Therefore, the study [2] used quantitative deconvolution algorithm developed by [3] for spectral unmixing of this composite thermal emissivity spectrum from telescope to their respective areal fractions of endmember spectra; however, the thermal emissivity of endmembers used in [2] is the inverted reflectance measurements (Kirchhoff's law) of various samples measured at room temperature and pressure. Over a decade, the Planetary Spectroscopy Laboratory (PSL) at the Institute of Planetary Research (PF) at the German Aerospace Center (DLR) facilitates the thermal emissivity measurements under controlled and simulated surface conditions of Mercury by taking emissivity measurements at varying temperatures from 100-500°C under vacuum conditions supporting MERTIS payload. The measured thermal emissivity endmember spectral library therefore includes major silicates such as bytownite, anorthoclase, synthetic glass, olivine, enstatite, nepheline basanite, rocks like komatiite, tektite, Johnson Space Center lunar simulant (1A), and synthetic powdered sulfides which includes MgS, FeS, CaS, CrS, TiS, NaS, and MnS. Using such specialized endmember spectral library created under Mercury's conditions significantly increases the accuracy of the deconvolution model results. In this study, we revisited the available telescope spectra and redeveloped the algorithm by [3] by only choosing the endmember spectral library created at PSL for unbiased model

  6. Generation and Use of Thermal Energy in the U.S. Industrial Sector and Opportunities to Reduce its Carbon Emissions

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, Colin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Boardman, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); McKellar, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bragg-Sitton, Shannon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-12-01

    This report quantifies greenhouse gas (GHG) emissions from the industrial sector and identifies opportunities for non-GHG-emitting thermal energy sources to replace the most significant GHG-emitting U.S. industries based on targeted, process-level analysis of industrial heat requirements. The intent is to provide a basis for projecting opportunities for clean energy use. This provides a prospectus for small modular nuclear reactors (including nuclear-renewable hybrid energy systems), solar industrial process heat, and geothermal energy. This report provides a complement to analysis of process-efficiency improvement by considering how clean energy delivery and use by industry could reduce GHG emissions.

  7. Typical calculation and analysis of carbon emissions in thermal power plants

    Science.gov (United States)

    Gai, Zhi-jie; Zhao, Jian-gang; Zhang, Gang

    2018-03-01

    On December 19, 2017, the national development and reform commission issued the national carbon emissions trading market construction plan (power generation industry), which officially launched the construction process of the carbon emissions trading market. The plan promotes a phased advance in carbon market construction, taking the power industry with a large carbon footprint as a breakthrough, so it is extremely urgent for power generation plants to master their carbon emissions. Taking a coal power plant as an example, the paper introduces the calculation process of carbon emissions, and comes to the fuel activity level, fuel emissions factor and carbon emissions data of the power plant. Power plants can master their carbon emissions according to this paper, increase knowledge in the field of carbon reserves, and make the plant be familiar with calculation method based on the power industry carbon emissions data, which can help power plants positioning accurately in the upcoming carbon emissions trading market.

  8. Housing and sustainable development: perspectives offered by thermal solar energy. Particle emissions: prospective investigation of primary particle emissions in France by 2030

    International Nuclear Information System (INIS)

    Brignon, J.M.; Cauret, L.; Sambat, S.

    2004-09-01

    This publication proposes two investigation reports. A first study proposes a prospective analysis of the housing 'stock' in France and the evolution of global energy consumptions and CO 2 emissions by the housing sector, a prospective study of space heating and hot water needs by defining reference scenarios as well as a target scenario for heating consumption (based on the factor 4 of reduction of emissions by 2050), and an assessment of the contribution of the thermal solar energy applied to winter comfort under the form of direct solar floors and passive solar contributions, and applied to hot water by 2050. The contribution of the thermal solar energy is studied within its regulatory context. An analysis of urban forms is also performed to assess the potential of integration of renewable energy solutions in the existing housing stock, and thus to assess the morphological limits of an attempt of generalized solarization of roofs. The second study proposes a detailed identification and assessment of the various sources of primary particles (combustion, industrial processes, mineral extraction and processing, road transport, waste processing and elimination, agriculture, natural sources, forest fires), providing more precise results and methodological complements for some sources. It also proposes a prospective assessment of emissions and identifies the main factors of particle concentrations in urban environment

  9. The performance of DC restoration function for MODIS thermal emissive bands

    Science.gov (United States)

    Wang, Zhipeng; Xiong, Xiaoxiong Jack; Shrestha, Ashish

    2017-09-01

    The DC restore (DCR) process of MODIS instrument maintains the output of a detector at focal plane assembly (FPA) within the dynamic range of subsequent analog-to-digital converter, by adding a specific offset voltage to the output. The DCR offset value is adjusted per scan, based on the comparison of the detector response in digital number (DN) collected from the blackbody (BB) view with target DN saved as an on-board look-up table. In this work, the MODIS DCR mechanism is revisited, with the trends of DCR offset being provided for thermal emissive bands (TEB). Noticeable changes have been occasionally found which coincide with significant detector gain change due to various instrumental events such as safe-mode anomaly or FPA temperature fluctuation. In general, MODIS DCR functionality has been effective and the change of DCR offset has no impact to the quality of MODIS data. One exception is the Earth view (EV) data saturation of Aqua MODIS LWIR bands 33, 35 ad 36 during BB warm-up cool-down (WUCD) cycle which has been observed since 2008. The BB view of their detectors saturate when the BB temperature is above certain threshold so the DCR cannot work as designed. Therefore, the dark signal DN fluctuates with the cold FPA (CFPA) temperature and saturate for a few hours per WUCD cycle, which also saturate the EV data sector within the scan. The CFPA temperature fluctuation peaked in 2012 and has been reduced in recent years and the saturation phenomenon has been easing accordingly. This study demonstrates the importance of DCR to data generation.

  10. Evaluation of VIIRS and MODIS Thermal Emissive Band Calibration Stability Using Ground Target

    Directory of Open Access Journals (Sweden)

    Sriharsha Madhavan

    2016-02-01

    Full Text Available The S-NPP Visible Infrared Imaging Radiometer Suite (VIIRS instrument, a polar orbiting Earth remote sensing instrument built using a strong MODIS background, employs a similarly designed on-board calibrating source—a V-grooved blackbody for the Thermal Emissive Bands (TEB. The central wavelengths of most VIIRS TEBs are very close to those of MODIS with the exception of the 10.7 µm channel. To ensure the long term continuity of climate data records derived using VIIRS and MODIS TEB, it is necessary to assess any systematic differences between the two instruments, including scenes with temperatures significantly lower than blackbody operating temperatures at approximately 290 K. Previous work performed by the MODIS Characterization Support Team (MCST at NASA/GSFC used the frequent observations of the Dome Concordia site located in Antarctica to evaluate the calibration stability and consistency of Terra and Aqua MODIS over the mission lifetime. The near-surface temperature measurements from an automatic weather station (AWS provide a direct reference useful for tracking the stability and determining the relative bias between the two MODIS instruments. In this study, the same technique is applied to the VIIRS TEB and the results are compared with those from the matched MODIS TEB. The results of this study show a small negative bias when comparing the matching VIIRS and Aqua MODIS TEB, implying a higher brightness temperature for S-VIIRS at the cold end. Statistically no significant drift is observed for VIIRS TEB performance over the first 3.5 years of the mission.

  11. Thermal energy consumption and carbon dioxide emissions in ceramic tile manufacture - Analysis of the Spanish and Brazilian industries

    International Nuclear Information System (INIS)

    Monfort, E.; Mezquita, A.; Vaquer, E.; Mallol, G.; Alves, H. J.; Boschi, A. O.

    2012-01-01

    Spain and Brazil are two of the world's biggest ceramic tile producers. The tile manufacturing process consumes a great quantity of thermal energy that, in these two countries, is mainly obtained from natural gas combustion, which entails CO 2 emission, a greenhouse gas. This study presents a comparative analysis of the thermal energy consumption and CO 2 emissions in the ceramic tile manufacturing process in Spain and Brazil, in terms of the different production technologies and different products made. The energy consumption and CO 2 emissions in ceramic tile manufacture by the wet process are very similar in both countries. In the dry process used in Brazil, less thermal energy is consumed and less CO 2 is emitted than in the wet process, but it is a process that is only used in manufacturing one particular type of product, which exhibits certain technical limitations. While in Spain the use of cogeneration systems in spray-dryers improves significantly the global energy efficiency. The average energy consumption in the different process stages, in both countries, lies within the range indicated in the Reference Document on Best Available Techniques in the Ceramic Manufacturing Industry (BREF of the Ceramic Manufacturing Industry) of the European Union. (Author) 14 refs.

  12. THE NON-THERMAL, TIME-VARIABLE RADIO EMISSION FROM Cyg OB2 no. 5: A WIND-COLLISION REGION

    International Nuclear Information System (INIS)

    Ortiz-Leon, Gisela N.; Loinard, Laurent; RodrIguez, Luis F.; Dzib, Sergio A.; Mioduszewski, Amy J.

    2011-01-01

    The radio emission from the well-studied massive stellar system Cyg OB2 no. 5 is known to fluctuate with a period of 6.7 years between a low-flux state, when the emission is entirely of free-free origin, and a high-flux state, when an additional non-thermal component (of hitherto unknown nature) appears. In this paper, we demonstrate that the radio flux of that non-thermal component is steady on timescales of hours and that its morphology is arc-like. This shows that the non-thermal emission results from the collision between the strong wind driven by the known contact binary in the system and that of an unseen companion on a somewhat eccentric orbit with a 6.7 year period and a 5-10 mas semimajor axis. Together with the previously reported wind-collision region located about 0.''8 to the northeast of the contact binary, so far Cyg OB2 no. 5 appears to be the only multiple system known to harbor two radio-imaged wind-collision regions.

  13. A SYSTEMATIC STUDY OF THE THERMAL AND NONTHERMAL EMISSION IN THE SUPERNOVA REMNANT RCW 86 WITH SUZAKU

    International Nuclear Information System (INIS)

    Tsubone, Yoshio; Sawada, Makoto; Bamba, Aya; Katsuda, Satoru; Vink, Jacco

    2017-01-01

    Diffusive shock acceleration by the shockwaves in supernova remnants (SNRs) is widely accepted as the dominant source for Galactic cosmic rays. However, it is unknown what determines the maximum energy of accelerated particles. The surrounding environment could be one of the key parameters. The SNR RCW 86 shows both thermal and nonthermal X-ray emission with different spatial morphologies. These emission originate from the shock-heated plasma and accelerated electrons respectively, and their intensities reflect their density distributions. Thus, the remnant provides a suitable laboratory to test possible association between the acceleration efficiency and the environment. In this paper, we present results of spatially resolved spectroscopy of the entire remnant with Suzaku . The spacially resolved spectra are well reproduced with a combination of a power-law for synchrotron emission and a two-component optically thin thermal plasma, corresponding to the shocked interstellar medium (ISM) with kT of 0.3–0.6 keV and Fe-dominated ejecta. It is discovered that the photon index of the nonthermal component becomes smaller when decreasing the emission measure of the shocked ISM, where the shock speed has remained high. This result implies that the maximum energy of accelerated electrons in RCW 86 is higher in the low-density and higher shock speed regions.

  14. Economic and Environmental Considerations for Zero-emission Transport and Thermal Energy Generation on an Energy Autonomous Island

    Directory of Open Access Journals (Sweden)

    Fontina Petrakopoulou

    2018-01-01

    Full Text Available The high cost and environmental impact of fossil-fuel energy generation in remote regions can make renewable energy applications more competitive than business-as-usual scenarios. Furthermore, energy and transport are two of the main sectors that significantly contribute to global greenhouse gas emissions. This paper focuses on the generation of thermal energy and the transport sector of a fossil fuel-based energy independent island in Greece. We evaluate (1 technologies for fully renewable thermal energy generation using building-specific solar thermal systems and (2 the replacement of the vehicle fleet of the island with electric and hydrogen-fueled vehicles. The analysis, based on economic and environmental criteria, shows that although solar thermal decreases greenhouse gases by 83%, when compared to the current diesel-based situation, it only becomes economically attractive with subsidy scenarios equal to or higher than 50%. However, in the transport sector, the sum of fuel and maintenance costs of fuel-cell and electric vehicles is found to be 45% lower than that of the current fleet, due to their approximately seven times lower fuel cost. Lastly, it will take approximately six years of use of the new vehicles to balance out the emissions of their manufacturing phase.

  15. Non Thermal Emission from Clusters of Galaxies: the Importance of a Joint LOFAR/Simbol-X View

    Science.gov (United States)

    Ferrari, C.

    2009-05-01

    Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources (``halos'' and ``relics'') related to the presence of relativistic electrons and weak magnetic fields in the intracluster volume. I will outline our current knowledge about the presence and properties of this non-thermal cluster component. Despite the recent progress made in observational and theoretical studies of the non-thermal emission in galaxy clusters, a number of open questions about its origin and its effects on the thermo-dynamical evolution of galaxy clusters need to be answered. I will show the importance of combining galaxy cluster observations by new-generation instruments such as LOFAR and Simbol-X. A deeper knowledge of the non-thermal cluster component, together with statistical studies of radio halos and relics, will allow to test the current cluster formation scenario and to better constrain the physics of large scale structure evolution.

  16. Non Thermal Emission from Clusters of Galaxies: the Importance of a Joint LOFAR/Simbol-X View

    International Nuclear Information System (INIS)

    Ferrari, C.

    2009-01-01

    Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources ('halos' and 'relics') related to the presence of relativistic electrons and weak magnetic fields in the intracluster volume. I will outline our current knowledge about the presence and properties of this non-thermal cluster component. Despite the recent progress made in observational and theoretical studies of the non-thermal emission in galaxy clusters, a number of open questions about its origin and its effects on the thermo-dynamical evolution of galaxy clusters need to be answered. I will show the importance of combining galaxy cluster observations by new-generation instruments such as LOFAR and Simbol-X. A deeper knowledge of the non-thermal cluster component, together with statistical studies of radio halos and relics, will allow to test the current cluster formation scenario and to better constrain the physics of large scale structure evolution.

  17. Monitoring and inventorying of the pollutant emissions from thermal power plants

    International Nuclear Information System (INIS)

    Vladescu, Gherghina; Iordache, Daniela; Iordache, Victorita; Ciomaga, Carmencita; Matei, Magdalena; Ilie, Ion; Motiu, Cornel

    2001-01-01

    Pollution due to emissions discharged in atmosphere as a result of human (anthropogenic) activities and the related environmental effects, such as acid depositions, land quality degradation, global warming/climate changes, building degradation, ozone layer depletion required the monitoring and inventorying of the polluting emissions at the local, regional and global levels. The paper briefly presents the international requirements concerning the development of a polluting emission inventory, the European methodologies for air polluting emission inventorying, programs and methodologies used in the Romanian electricity production sector for inventorying the polluting emissions and calculation of the dispersion of the pollutants discharged in the atmosphere. (author)

  18. Challenges of UV light processing of low UVT foods and beverages

    Science.gov (United States)

    Koutchma, Tatiana

    2010-08-01

    Ultraviolet (UV) technology holds promise as a low cost non-thermal alternative to heat pasteurization of liquid foods and beverages. However, its application for foods is still limited due to low UV transmittance (LUVT). LUVT foods have a diverse range of chemical (pH, Brix, Aw), physical (density and viscosity) and optical properties (absorbance and scattering) that are critical for systems and process designs. The commercially available UV sources tested for foods include low and medium pressure mercury lamps (LPM and MPM), excimer and pulsed lamps (PUV). The LPM and excimer lamps are monochromatic sources whereas emission of MPM and PUV is polychromatic. The optimized design of UV-systems and UV-sources with parameters that match to specific product spectra have a potential to make UV treatments of LUVT foods more effective and will serve its further commercialization. In order to select UV source for specific food application, processing effects on nutritional, quality, sensorial and safety markers have to be evaluated. This paper will review current status of UV technology for food processing along with regulatory requirements. Discussion of approaches and results of measurements of chemico-physical and optical properties of various foods (fresh juices, milk, liquid whey proteins and sweeteners) that are critical for UV process and systems design will follow. Available UV sources did not prove totally effective either resulting in low microbial reduction or UV over-dosing of the product thereby leading to sensory changes. Beam shaping of UV light presents new opportunities to improve dosage uniformity and delivery of UV photons in LUVT foods.

  19. THERMAL CHARACTERISTICS AND THE DIFFERENTIAL EMISSION MEASURE DISTRIBUTION DURING A B8.3 FLARE ON 2009 JULY 4

    Energy Technology Data Exchange (ETDEWEB)

    Awasthi, Arun Kumar [Astronomical Institute, University of Wroclaw, Wroclaw (Poland); Sylwester, Barbara; Sylwester, Janusz [Solar Physics Division, Space Research Centre, Polish Academy of Sciences, Wroclaw (Poland); Jain, Rajmal, E-mail: arun.awasthi.87@gmail.com, E-mail: awasthi@astro.uni.wroc.pl [Kadi Sarva Vishwavidyalaya, Gandhinagar, Gujarat (India)

    2016-06-01

    We investigate the evolution of the differential emission measure distribution (DEM[ T ]) in various phases of a B8.3 flare which occurred on 2009 July 04. We analyze the soft X-ray (SXR) emission in the 1.6–8.0 keV range, recorded collectively by the Solar Photometer in X-rays (SphinX; Polish) and the Solar X-ray Spectrometer (Indian) instruments. We conduct a comparative investigation of the best-fit DEM[ T ] distributions derived by employing various inversion schemes, namely, single Gaussian, power-law functions and a Withbroe–Sylwester (W–S) maximum likelihood algorithm. In addition, the SXR spectrum in three different energy bands, that is, 1.6–5.0 keV (low), 5.0–8.0 keV (high), and 1.6–8.0 keV (combined), is analyzed to determine the dependence of the best-fit DEM[ T ] distribution on the selection of the energy interval. The evolution of the DEM[ T ] distribution, derived using a W–S algorithm, reveals multi-thermal plasma during the rise to the maximum phase of the flare, and isothermal plasma in the post-maximum phase of the flare. The thermal energy content is estimated by considering the flare plasma to be (1) isothermal and (2) multi-thermal in nature. We find that the energy content during the flare, estimated using the multi-thermal approach, is in good agreement with that derived using the isothermal assumption, except during the flare maximum. Furthermore, the (multi-) thermal energy estimated while employing the low-energy band of the SXR spectrum results in higher values than that derived from the combined energy band. On the contrary, the analysis of the high-energy band of the SXR spectrum leads to lower thermal energy than that estimated from the combined energy band.

  20. Impact of raw pig slurry and pig farming practices on physicochemical parameters and on atmospheric N2O and CH 4 emissions of tropical soils, Uvéa Island (South Pacific).

    Science.gov (United States)

    Roth, E; Gunkel-Grillon, P; Joly, L; Thomas, X; Decarpenterie, T; Mappe-Fogaing, I; Laporte-Magoni, C; Dumelié, N; Durry, G

    2014-09-01

    Emissions of CH4 and N2O related to private pig farming under a tropical climate in Uvéa Island were studied in this paper. Physicochemical soil parameters such as nitrate, nitrite, ammonium, Kjeldahl nitrogen, total organic carbon, pH and moisture were measured. Gaseous soil emissions as well as physicochemical parameters were compared in two private pig farming strategies encountered on this island on two different soils (calcareous and ferralitic) in order to determine the best pig farming management: in small concrete pens or in large land pens. Ammonium levels were higher in control areas while nitrate and nitrite levels were higher in soils with pig slurry inputs, indicating that nitrification was the predominant process related to N2O emissions. Nitrate contents in soils near concrete pens were important (≥ 55 μg N/g) and can thus be a threat for the groundwater. For both pig farming strategies, N2O and CH4 fluxes can reach high levels up to 1 mg N/m(2)/h and 1 mg C/m(2)/h, respectively. CH4 emissions near concrete pens were very high (≥ 10.4 mg C/m(2)/h). Former land pens converted into agricultural land recover low N2O emission rates (≤ 0.03 mg N/m(2)/h), and methane uptake dominates. N2O emissions were related to nitrate content whereas CH4 emissions were found to be moisture dependent. As a result relating to the physicochemical parameters as well as to the gaseous emissions, we demonstrate that pig farming in large land pens is the best strategy for sustainable family pig breeding in Uvéa Islands and therefore in similar small tropical islands.

  1. THERMAL EMISSION IN THE EARLY X-RAY AFTERGLOWS OF GAMMA-RAY BURSTS: FOLLOWING THE PROMPT PHASE TO LATE TIMES

    Energy Technology Data Exchange (ETDEWEB)

    Friis, Mette [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Watson, Darach, E-mail: mef4@hi.is, E-mail: darach@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark)

    2013-07-01

    Thermal radiation, peaking in soft X-rays, has now been detected in a handful of gamma-ray burst (GRB) afterglows and has to date been interpreted as shock break-out of the GRB's progenitor star. We present a search for thermal emission in the early X-ray afterglows of a sample of Swift bursts selected by their brightness in X-rays at early times. We identify a clear thermal component in eight GRBs and track the evolution. We show that at least some of the emission must come from highly relativistic material since two show an apparent super-luminal expansion of the thermal component. Furthermore, we determine very large luminosities and high temperatures for many of the components-too high to originate in a supernova shock break-out. Instead, we suggest that the component may be modeled as late photospheric emission from the jet, linking it to the apparently thermal component observed in the prompt emission of some GRBs at gamma-ray and hard X-ray energies. By comparing the parameters from the prompt emission and the early afterglow emission, we find that the results are compatible with the interpretation that we are observing the prompt quasi-thermal emission component in soft X-rays at a later point in its evolution.

  2. Generation and Use of Thermal Energy in the U.S. Industrial Sector and Opportunities to Reduce its Carbon Emissions

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, Colin A. [National Renewable Energy Lab. (NREL), Golden, CO (United States). Strategic Energy Analysis Center; Boardman, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); McKellar, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bragg-Sitton, Shannon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-11-01

    The industrial sector was the third-largest source of direct U.S. greenhouse gas (GHG) emissions in 2014 behind electricity generation and transportation and accounted for roughly 20% of total emissions (EPA 2016). The Energy Information Administration (EIA) projects that total U.S. energy consumption will grow to about 108 exajoules (1 EJ = 1018 J) or 102 quads (1 quad = 1015 British thermal units) in 2025, with nearly all of the growth coming from the industrial sector (DOE 2015b). Energy consumption in the industrial sector is forecast to increase to 39.5 EJ (37.4 quads)—a 22% increase, exceeding 36% of total energy consumption in the United States. Therefore, it is imperative that industrial GHG emissions be considered in any strategy intent on achieving deep decarbonization of the energy sector as a whole. It is important to note that unlike the transportation sector and electrical grid, energy use by industry often involves direct conversion of primary energy sources to thermal and electrical energy at the point of consumption. About 52% of U.S. industrial direct GHG emissions are the result of fuel combustion (EPA 2016) to produce hot gases and steam for process heating, process reactions, and process evaporation, concentration, and drying. The heterogeneity and variations in scale of U.S. industry and the complexity of modern industrial firms’ global supply chains are among the sector’s unique challenges to minimizing its GHG emissions. A combination of varied strategies—such as energy efficiency, material efficiency, and switching to low-carbon fuels—can help reduce absolute industrial GHG emissions. This report provides a complement to process-efficiency improvement to consider how clean energy delivery and use by industry could reduce GHG emissions. Specifically, it considers the possibility of replacing fossil-fuel combustion in industry with nuclear (specifically small modular reactors [SMRs]), solar thermal (referred to

  3. Complex UV/X-ray variability of 1H 0707-495

    Science.gov (United States)

    Pawar, P. K.; Dewangan, G. C.; Papadakis, I. E.; Patil, M. K.; Pal, Main; Kembhavi, A. K.

    2017-12-01

    We study the relationship between the UV and X-ray variability of the narrow-line Seyfert 1 galaxy 1H 0707-495. Using a year-long Swift monitoring and four long XMM-Newton observations, we perform cross-correlation analyses of the UV and X-ray light curves, on both long and short time-scales. We also perform time-resolved X-ray spectroscopy on 1-2 ks scale, and study the relationship between the UV emission and the X-ray spectral components - soft X-ray excess and a power law. We find that the UV and X-ray variations anticorrelate on short, and possibly on long time-scales as well. Our results rule out reprocessing as the dominant mechanism for the UV variability, as well as the inward propagating fluctuations in the accretion rate. Absence of a positive correlation between the photon index and the UV flux suggests that the observed UV emission is unlikely to be the seed photons for the thermal Comptonization. We find a strong correlation between the continuum flux and the soft-excess temperature which implies that the soft excess is most likely the reprocessed X-ray emission in the inner accretion disc. Strong X-ray heating of the innermost regions in the disc, due to gravitational light bending, appears to be an important effect in 1H 0707-495, giving rise to a significant fraction of the soft excess as reprocessed thermal emission. We also find indications for a non-static, dynamic X-ray corona, where either the size or height (or both) vary with time.

  4. Using copper substrate to enhance the thermal conductivity of top-emission organic light-emitting diodes for improving the luminance efficiency and lifetime

    Science.gov (United States)

    Tsai, Yu-Sheng; Wang, Shun-Hsi; Chen, Chuan-Hung; Cheng, Chien-Lung; Liao, Teh-Chao

    2009-12-01

    The influence of heat dissipation on the performances of organic light-emitting diode (OLED) is investigated by measuring junction temperature and by calculating the rate of heat flow. The calculated rate of heat flow reveals that the key factors include the thermal conductivity, the substrate thickness, and the UV glue. Moreover, the use of copper substrate can effectively dissipate the joule heat, which then reduces the temperature gradient. Finally, it is shown that the use of a high thermal conductivity thinner substrate can enhance the thermal conductivity of OLED and the luminance efficiency as well.

  5. HYDRO2GEN: Non-thermal hydrogen Balmer and Paschen emission in solar flares generated by electron beams

    Science.gov (United States)

    Druett, M. K.; Zharkova, V. V.

    2018-03-01

    Aim. Sharp rises of hard X-ray (HXR) emission accompanied by Hα line profiles with strong red-shifts up to 4 Å from the central wavelength, often observed at the onset of flares with the Specola Solare Ticinese Telescope (STT) and the Swedish Solar Telescope (SST), are not fully explained by existing radiative models. Moreover, observations of white light (WL) and Balmer continuum emission with the Interface Region Imaging Spectrograph (IRISH) reveal strong co-temporal enhancements and are often nearly co-spatial with HXR emission. These effects indicate a fast effective source of excitation and ionisation of hydrogen atoms in flaring atmospheres associated with HXR emission. In this paper, we investigate electron beams as the agents accounting for the observed hydrogen line and continuum emission. Methods: Flaring atmospheres are considered to be produced by a 1D hydrodynamic response to the injection of an electron beam defining their kinetic temperatures, densities, and macro velocities. We simulated a radiative response in these atmospheres using a fully non-local thermodynamic equilibrium (NLTE) approach for a 5-level plus continuum hydrogen atom model, considering its excitation and ionisation by spontaneous, external, and internal diffusive radiation and by inelastic collisions with thermal and beam electrons. Simultaneous steady-state and integral radiative transfer equations in all optically thick transitions (Lyman and Balmer series) were solved iteratively for all the transitions to define their source functions with the relative accuracy of 10-5. The solutions of the radiative transfer equations were found using the L2 approximation. Resulting intensities of hydrogen line and continuum emission were also calculated for Balmer and Paschen series. Results: We find that inelastic collisions with beam electrons strongly increase excitation and ionisation of hydrogen atoms from the chromosphere to photosphere. This leads to an increase in Lyman continuum

  6. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  7. Probing the non-thermal emission in Abell 2146 and the Perseus cluster with the JVLA

    Science.gov (United States)

    Gendron-Marsolais, Marie-Lou; Hlavacek-Larrondo, Julie; van Weeren, Reinout; Clarke, Tracy; Intema, Huib; Russell, Helen; Edge, Alastair; Fabian, Andy; Olamaie, Malak; Rumsey, Clare; King, Lindsay; McNamara, Brian; Fecteau-Beaucage, David; Hogan, Michael; Mezcua, Mar; Taylor, Gregory; Blundell, Katherine; Sanders, Jeremy

    2018-01-01

    Jets created from accretion onto supermassive black holes release relativistic particles on large distances. These strongly affect the intracluster medium when located in the center of a brightest cluster galaxy. The hierarchical merging of subclusters and groups, from which cluster originate, also generates perturbations into the intracluster medium through shocks and turbulence, constituting a potential source of reacceleration for these particles. I will present deep multi-configuration low radio frequency observations from the Karl G. Jansky Very Large Array of two unique clusters, probing the non-thermal emission from the old particle population of the AGN outflows.Recently awarded of 550 hours of Chandra observations, Abell 2146 is one of the rare clusters undergoing a spectacular merger in the plane of the sky. Our recent deep multi-configuration JVLA 1.4 GHz observations have revealed the presence of a structure extending to 850 kpc in size, consisting of one component associated with the upstream shock and classified as a radio relic, and one associated with the subcluster core, consistent with a radio halo bounded by the bow shock. Theses structures have some of the lowest radio powers detected thus far in any cluster. The flux measurements of the halo, its morphology and measurements of the dynamical state of the cluster suggest that the halo was recently created (~ 0.3 Gyr after core passage). This makes A2146 extremely interesting to study, allowing us to probe the complete evolutionary stages of halos.I will also present results on 230-470 MHz JVLA observations of the Perseus cluster. Our observations of this nearby relaxed cool core cluster have revealed a multitude of new structures associated with the mini-halo, extending to hundreds of kpc in size. Its irregular morphology seems to be have been influenced both by the AGN activity and by the sloshing motion of the cluster’ gas. In addition, it has a filamentary structure similar to that seen in

  8. Assessment of Mars Atmospheric Temperature Retrievals from the Thermal Emission Spectrometer Radiances

    Science.gov (United States)

    Hoffman, Matthew J.; Eluszkiewicz, Janusz; Weisenstein, Deborah; Uymin, Gennady; Moncet, Jean-Luc

    2012-01-01

    Motivated by the needs of Mars data assimilation. particularly quantification of measurement errors and generation of averaging kernels. we have evaluated atmospheric temperature retrievals from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) radiances. Multiple sets of retrievals have been considered in this study; (1) retrievals available from the Planetary Data System (PDS), (2) retrievals based on variants of the retrieval algorithm used to generate the PDS retrievals, and (3) retrievals produced using the Mars 1-Dimensional Retrieval (M1R) algorithm based on the Optimal Spectral Sampling (OSS ) forward model. The retrieved temperature profiles are compared to the MGS Radio Science (RS) temperature profiles. For the samples tested, the M1R temperature profiles can be made to agree within 2 K with the RS temperature profiles, but only after tuning the prior and error statistics. Use of a global prior that does not take into account the seasonal dependence leads errors of up 6 K. In polar samples. errors relative to the RS temperature profiles are even larger. In these samples, the PDS temperature profiles also exhibit a poor fit with RS temperatures. This fit is worse than reported in previous studies, indicating that the lack of fit is due to a bias correction to TES radiances implemented after 2004. To explain the differences between the PDS and Ml R temperatures, the algorithms are compared directly, with the OSS forward model inserted into the PDS algorithm. Factors such as the filtering parameter, the use of linear versus nonlinear constrained inversion, and the choice of the forward model, are found to contribute heavily to the differences in the temperature profiles retrieved in the polar regions, resulting in uncertainties of up to 6 K. Even outside the poles, changes in the a priori statistics result in different profile shapes which all fit the radiances within the specified error. The importance of the a priori statistics prevents

  9. Increasing thermal drying temperature of biosolids reduced nitrogen mineralisation and soil N2O emissions

    DEFF Research Database (Denmark)

    Case, Sean; Gomez Muñoz, Beatriz; Magid, Jakob

    2016-01-01

    Previous studies found that thermally dried biosolids contained more mineralisable organic nitrogen (N) than the raw or anaerobically digested (AD) biosolids they were derived from. However, the effect of thermal drying temperature on biosolid N availability is not well understood. This will be o......Previous studies found that thermally dried biosolids contained more mineralisable organic nitrogen (N) than the raw or anaerobically digested (AD) biosolids they were derived from. However, the effect of thermal drying temperature on biosolid N availability is not well understood...

  10. CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

    Science.gov (United States)

    Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

    2017-09-01

    Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

  11. Influence of aging on the heat and gas emissions from commercial lithium ion cells in case of thermal failure

    Directory of Open Access Journals (Sweden)

    Michael Lammer

    2018-03-01

    Full Text Available A method for thermal ramp experiments on cylindrical 18650 Li-ion cells has been established. The method was applied on pristine cells as well as on devices aged by cyclisation or by storage at elevated temperature respectively. The tested cells comprise three types of LiNi0.8Co0.15Al0.05O2 cells for either high power or high energy applications. The heat flux to and from the cell was investigated. Degradation and exothermic breakdown released large amounts of heat and gas. The total gas and heat emission from cycled cells was significantly larger than emission from cells aged by storage. After aging, the low energy cell ICR18650HE4 did not transgress into thermal runaway. Gas composition changed mainly in the early stage of the experiment. The composition of the initial gas release changed from predominantly CO2 towards hydrocarbons. The thermal runaway emitted for all tests a comparable mixture of H2, CO and CO2.

  12. On-line thermal dependence study of the main solar cell electrical photoconversion parameters using low thermal emission lamps.

    Science.gov (United States)

    Gallardo, J J; Navas, J; Alcántara, R; Fernández-Lorenzo, C; Aguilar, T; Martín-Calleja, J

    2012-06-01

    This paper presents a non-conventional methodology and an instrumental system to measure the effect of temperature on the photovoltaic properties of solar cells. The system enables the direct measurement of the evolution of open-circuit voltage and short-circuit current intensity in relation to a continuously decreasing temperature. The system uses a high-intensity white light-emitting diode light source with low emissions of radiation in the infrared region of the electromagnetic spectrum, resulting in a reduced heating of the photovoltaic devices by the irradiation source itself. To check the goodness of the system and the methodology designed, several measurements were performed with monocrystalline silicon solar cells, dye-sensitized solar cells, and thin-film amorphous silicon solar cells, showing similar tendencies to those reported in the literature.

  13. An expression for the atomic fluorescence and thermal-emission intensity under conditions of near saturation and arbitrary self-absorption

    NARCIS (Netherlands)

    Omenetto, N.; Winefordner, J.D.; Alkemade, C.T.J.

    An expression for the effect of self-absorption on the fluorescence and thermal emission intensities is derived by taking into account stimulated emission. A simple, idealized case is considered, consisting of a two level atomic system, in a flame, homogeneous with respect to temperature and

  14. Broad band energy distribution of UV-bright BL Lac objects

    International Nuclear Information System (INIS)

    Maraschi, L.; Tanzi, E.G.; Treves, A.

    1984-01-01

    IUE satellite data in the 1200-2000 and 1900-3200 A intervals of BL Lac objects are analyzed in terms of two discernible groups. A total of 25 BL Lac objects were observed, with differences between groups displayed in terms of the power slope of the energy of the UV emissions, i.e., slopes of 1 and 2. Comparisons of the spectra with those of quasars showed that quasars have a small spectral index in the 1000-6000 A band and no correlation exists between the spectral index and UV flux of the BL Lac objects. The comparisons underscore the lack of a thermal component for BL Lac objects. Steep spectral components in both BL Lac objects and highly polarized quasars emissions could both be due to synchrotron emission. Compton scattering of relativistic electrons off synchrotron photons could produce the X ray emissions. 44 references

  15. Broad band energy distribution of UV-bright BL Lac objects

    Energy Technology Data Exchange (ETDEWEB)

    Maraschi, L.; Tanzi, E.G.; Treves, A.

    1984-01-01

    IUE satellite data in the 1200-2000 and 1900-3200 A intervals of BL Lac objects are analyzed in terms of two discernible groups. A total of 25 BL Lac objects were observed, with differences between groups displayed in terms of the power slope of the energy of the UV emissions, i.e., slopes of 1 and 2. Comparisons of the spectra with those of quasars showed that quasars have a small spectral index in the 1000-6000 A band and no correlation exists between the spectral index and UV flux of the BL Lac objects. The comparisons underscore the lack of a thermal component for BL Lac objects. Steep spectral components in both BL Lac objects and highly polarized quasars emissions could both be due to synchrotron emission. Compton scattering of relativistic electrons off synchrotron photons could produce the X ray emissions. 44 references.

  16. Quantitative analysis of UV excitation bands for red emissions in Pr3+-doped CaTiO3, SrTiO3 and BaTiO3 phosphors by peak fitting

    International Nuclear Information System (INIS)

    Fujiwara, Rei; Sano, Hiroyuki; Shimizu, Mikio; Kuwabara, Makoto

    2009-01-01

    A quantitative spectral analysis of the ultraviolet (UV) broad excitation bands, which are located in the range 300-400 nm, for red emissions at around 610 nm in Pr-doped CaTiO 3 , SrTiO 3 :Al and BaTiO 3 :Mg phosphors has been carried out using a peak fitting technique. The obtained results demonstrate that the UV broad band of CaTiO 3 :Pr consists of four primary excitation bands centered around 330, 335, 365 and 380 nm and those of both SrTiO 3 :Al and BaTiO 3 :Mg consist of three primary bands centered around 310, 345 and 370 nm. Based on the behavior patterns and the values of the respective primary excitation bands' parameters, i.e. center gravity (λ top ), maximum height (I max ) and full-width at half-maximum (FWHM), the UV-to-red relaxation processes in these titanate phosphors can be explained to be essentially the same, except for the existence of an additional relaxation pathway via electron-trap states in CaTiO 3 :Pr, which gives a characteristic shape of its UV excitation spectrum in the wavelength range of >360 nm

  17. Laser-Induced Fluorescence Emission (L.I.F.E.): searching for Mars organics with a UV-enhanced PanCam.

    Science.gov (United States)

    Storrie-Lombardi, Michael C; Muller, Jan-Peter; Fisk, Martin R; Cousins, Claire; Sattler, Birgit; Griffiths, Andrew D; Coates, Andrew J

    2009-12-01

    The European Space Agency will launch the ExoMars mission in 2016 with a primary goal of surveying the martian subsurface for evidence of organic material. We have recently investigated the utility of including either a 365 nm light-emitting diode or a 375 nm laser light source in the ExoMars rover panoramic camera (PanCam). Such a modification would make it feasible to monitor rover drill cuttings optically for the fluorescence signatures of aromatic organic molecules and map the distribution of polycyclic aromatic hydrocarbons (PAHs) as a function of depth to the 2 m limit of the ExoMars drill. The technique described requires no sample preparation, does not consume irreplaceable resources, and would allow mission control to prioritize deployment of organic detection experiments that require sample destruction, expenditure of non-replaceable consumables, or both. We report here for the first time laser-induced fluorescence emission (L.I.F.E.) imaging detection limits for anthracene, pyrene, and perylene targets doped onto a Mars analog granular peridotite with a 375 nm Nichia laser diode in optically uncorrected wide-angle mode. Data were collected via the Beagle 2 PanCam backup filter wheel fitted with original blue (440 nm), green (530 nm), and red (670 nm) filters. All three PAH species can be detected with the PanCam green (530 nm) filter. Detection limits in the green band for signal-to-noise ratios (S/N) > 10 are 49 parts per million (ppm) for anthracene, 145 ppm for pyrene, and 20 ppm for perylene. The anthracene detection limit improves to 7 ppm with use of the PanCam blue filter. We discuss soil-dependent detection limit constraints; use of UV excitation with other rover cameras, which provides higher spatial resolution; and the advantages of focused and wide-angle laser modes. Finally, we discuss application of L.I.F.E. techniques at multiple wavelengths for exploration of Mars analog extreme environments on Earth, including Icelandic hydrothermally

  18. The Multi-Instrument (EVE-RHESSI) DEM for Solar Flares, and Implications for Residual Non-Thermal Soft X-Ray Emission

    Science.gov (United States)

    McTiernan, James M.; Caspi, Amir; Warren, Harry

    2015-04-01

    In the soft X-ray energy range, solar flare spectra are typically dominated by thermal emission. The low energy extent of non-thermal emission can only be loosely quantified using currently available X-ray data. To address this issue, we combine observations from the EUV Variability Experiment (EVE) on-board the Solar Dynamics Observatory (SDO) with X-ray data from the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI). The improvement over the isothermal approximation is intended to resolve the ambiguity in the range where the thermal and non-thermal components may have similar photon fluxes. This "crossover" range can extend up to 30 keV for medium to large solar flares.Previous work (Caspi et.al. 2014ApJ...788L..31C) has concentrated on obtaining DEM models that fit both instruments' observations well. Now we are interested in any breaks and cutoffs in the "residual" non-thermal spectrum; i.e., the RHESSI spectrum that is left over after the DEM has accounted for the bulk of the soft X-ray emission. Thermal emission is again modeled using a DEM that is parametrized as multiple gaussians in temperature; the non-thermal emission is modeled as a photon spectrum obtained using a thin-target emission model ('thin2' from the SolarSoft Xray IDL package). Spectra for both instruments are fit simultaneously in a self-consistent manner. The results for non-thermal parameters then are compared with those found using RHESSI data alone, with isothermal and double-thermal models.

  19. Cosmic Rays and Non-thermal Emission Induced by Accretion of Cool Gas onto the Galactic Disk

    Science.gov (United States)

    Inoue, Susumu; Uchiyama, Yasunobu; Arakawa, Masanori; Renaud, Matthieu; Wada, Keiichi

    2017-11-01

    On both observational and theoretical grounds, the disk of our Galaxy should be accreting cool gas with temperature ≲ {10}5 K via the halo at a rate ˜1 {{M}⊙ {yr}}-1. At least some of this accretion is mediated by high-velocity clouds (HVCs), observed to be traveling in the halo with velocities of a few 100 km s-1 and occasionally impacting the disk at such velocities, especially in the outer regions of the Galaxy. We address the possibility of particle acceleration in shocks triggered by such HVC accretion events, and the detectability of consequent non-thermal emission in the radio to gamma-ray bands and high-energy neutrinos. For plausible shock velocities ˜ 300 {km} {{{s}}}-1 and magnetic field strengths ˜ 0.3{--}10 μ {{G}}, electrons and protons may be accelerated up to ˜1-10 TeV and ˜ 30{--}{10}3 TeV, respectively, in sufficiently strong adiabatic shocks during their lifetime of ˜ {10}6 {{yr}}. The resultant pion decay and inverse Compton gamma-rays may be the origin of some unidentified Galactic GeV-TeV sources, particularly the “dark” source HESS J1503-582 that is spatially coincident with the anomalous H I structure known as “forbidden-velocity wings.” Correlation of their locations with star-forming regions may be weak, absent, or even opposite. Non-thermal radio and X-ray emission from primary and/or secondary electrons may be detectable with deeper observations. The contribution of HVC accretion to Galactic cosmic rays is subdominant, but could be non-negligible in the outer Galaxy. As the thermal emission induced by HVC accretion is likely difficult to detect, observations of such phenomena may offer a unique perspective on probing gas accretion onto the Milky Way and other galaxies.

  20. Effects of potassium hydroxide post-treatments on the field-emission properties of thermal chemical vapor deposited carbon nanotubes.

    Science.gov (United States)

    Lee, Li-Ying; Lee, Shih-Fong; Chang, Yung-Ping; Hsiao, Wei-Shao

    2011-12-01

    In this study, a simple potassium hydroxide treatment was applied to functionalize the surface and to modify the structure of multi-walled carbon nanotubes grown on silicon substrates by thermal chemical vapor deposition. Scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and energy dispersive spectrometry were employed to investigate the mechanism causing the modified field-emission properties of carbon nanotubes. From our experimental data, the emitted currents of carbon nanotubes after potassium hydroxide treatment are enhanced by more than one order of magnitude compared with those of untreated carbon nanotubes. The emitted current density of carbon nanotubes increases from 0.44 mA/cm2 to 7.92 mA/cm2 after 30 minutes KOH treatment. This technique provides a simple, economical, and effective way to enhance the field-emission properties of carbon nanotubes.

  1. Effects of Neutron Emission on Fragment Mass and Kinetic Energy Distribution from Thermal Neutron-Induced Fission of 235U

    International Nuclear Information System (INIS)

    Montoya, M.; Rojas, J.; Saetone, E.

    2007-01-01

    The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of 235 U(n th ,f) have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions

  2. Electromagnetic scattering and emission by a fixed multi-particle object in local thermal equilibrium: General formalism.

    Science.gov (United States)

    Mishchenko, Michael I

    2017-10-01

    The majority of previous studies of the interaction of individual particles and multi-particle groups with electromagnetic field have focused on either elastic scattering in the presence of an external field or self-emission of electromagnetic radiation. In this paper we apply semi-classical fluctuational electrodynamics to address the ubiquitous scenario wherein a fixed particle or a fixed multi-particle group is exposed to an external quasi-polychromatic electromagnetic field as well as thermally emits its own electromagnetic radiation. We summarize the main relevant axioms of fluctuational electrodynamics, formulate in maximally rigorous mathematical terms the general scattering-emission problem for a fixed object, and derive such fundamental corollaries as the scattering-emission volume integral equation, the Lippmann-Schwinger equation for the dyadic transition operator, the multi-particle scattering-emission equations, and the far-field limit. We show that in the framework of fluctuational electrodynamics, the computation of the self-emitted component of the total field is completely separated from that of the elastically scattered field. The same is true of the computation of the emitted and elastically scattered components of quadratic/bilinear forms in the total electromagnetic field. These results pave the way to the practical computation of relevant optical observables.

  3. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C. A. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  4. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C A [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  5. Characterization of Jupiter's Atmosphere from Observation of Thermal Emission by Juno and Ground-Based Supporting Observations

    Science.gov (United States)

    Orton, G. S.; Momary, T.; Tabataba-Vakili, F.; Janssen, M. A.; Hansen, C. J.; Bolton, S. J.; Li, C.; Adriani, A.; Mura, A.; Grassi, D.; Fletcher, L. N.; Brown, S. T.; Fujiyoshi, T.; Greathouse, T. K.; Kasaba, Y.; Sato, T. M.; Stephens, A.; Donnelly, P.; Eichstädt, G.; Rogers, J.

    2017-12-01

    Ground-breaking measurements of thermal emission at very long wavelengths have been made by the Juno mission's Microwave Radiometer (MWR). We examine the relationship between these and other thermal emission measurements by the Jupiter Infrared Auroral Mapper (JIRAM) at 5 µm and ground-based supporting observations in the thermal infrared that cover the 5-25 µm range. The relevant ground-based observations of thermal emission are constituted from imaging and scanning spectroscopy obtained at the NASA Infrared Telescope Facility (IRTF), the Gemini North Telescope, the Subaru Telescope and the Very Large Telescope. A comparison of these results clarifies the physical properties responsible for the observed emissions, i.e. variability of the temperature field, the cloud field or the distribution of gaseous ammonia. Cross-references to the visible cloud field from Juno's JunoCam experiment and Earth-based images are also useful. This work continues an initial comparison by Orton et al. (2017, GRL 44, doi: 10.1002/2017GL073019) between MWR and JIRAM results, together with ancillary 5-µm IRTF imaging and with JunoCam and ground-based visible imaging. These showed a general agreement between MWR and JIRAM results for the 5-bar NH3 abundance in specific regions of low cloud opacity but only a partial correlation between MWR and 5-µm radiances emerging from the 0.5-5 bar levels of the atmosphere in general. Similar to the latter, there appears to be an inconsistent correlation between MWR channels sensitive to 0.5-10 bars and shorter-wavelength radiances in the "tails" of 5-µm hot spots , which may be the result of the greater sensitivity of the latter to particulate opacity that could depend on the evolution history of the particular features sampled. Of great importance is the interpretation of MWR radiances in terms of the variability of temperature vs. NH3 abundances in the 0.5-5 bar pressure range. This is particularly important to understand MWR results in

  6. Thermal energy creation and transport and X-ray/EUV emission in a thermodynamic MHD CME simulation

    Science.gov (United States)

    Reeves, K.; Mikic, Z.; Torok, T.; Linker, J.; Murphy, N. A.

    2017-12-01

    We model a CME using the PSI 3D numerical MHD code that includes coronal heating, thermal conduction and radiative cooling in the energy equation. The magnetic flux distribution at 1 Rs is produced by a localized subsurface dipole superimposed on a global dipole field, mimicking the presence of an active region within the global corona. We introduce transverse electric fields near the neutral line in the active region to form a flux rope, then a converging flow is imposed that causes the eruption. We follow the formation and evolution of the current sheet and find that instabilities set in soon after the reconnection commences. We simulate XRT and AIA EUV emission and find that the instabilities manifest as bright features emanating from the reconnection region. We examine the quantities responsible for plasma heating and cooling during the eruption, including thermal conduction, radiation, adiabatic compression and expansion, coronal heating and ohmic heating due to dissipation of currents. We find that the adiabatic compression plays an important role in heating the plasma around the current sheet, especially in the later stages of the eruption when the instabilities are present. Thermal conduction also plays an important role in the transport of thermal energy away from the current sheet region throughout the reconnection process.

  7. Methodology for calculation of carbon emission and energy generation efficiency by fossil coal thermal power plants

    International Nuclear Information System (INIS)

    Licks, Leticia A.; Pires, Marcal

    2008-01-01

    This work intends to evaluate the emissions of carbon dioxide (CO 2 ) emitted by the burning of fossil coal in Brazil. So, a detailed methodology is proposed for calculation of CO 2 emissions from the carbon emission coefficients specific for the Brazilian carbons. Also, the using of secondary fuels (fuel oil and diesel oil) were considered and the power generation for the calculation of emissions and efficiencies of each power plant as well. The obtained results indicate carbon emissions for the year 2002 approximately of the order of 1,794 Gg, with 20% less than the obtained by the official methodology (MCT). Such differences are related to the non consideration of the humidity containment of the coals as well as the using of generic coefficients not adapted to the Brazilian coals. The obtained results indicate the necessity to review the emission inventories and the modernization of the burning systems aiming the increase the efficiency and reduction of the CO 2 and other pollutants, as an alternative for maintaining the sustainable form of using the fossil coal in the country

  8. Optical and thermal design of 1.5-m aperture solar UV visible and IR observing telescope for Solar-C mission

    Science.gov (United States)

    Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Horiuchi, T.; Matsumoto, Y.; Takeyama, N.

    2017-11-01

    order of magnitude more photons than SOT, relatively shorter telescope length of 2.8 m to accommodate a launcher's nosecone size for possible dual-satellite-launch configuration, and much wider observing wavelength from UV (down to 250 nm) through near IR (up to 1100 nm). The large aperture is essentially important to attain scientific goals of the plan-B, especially for accurate diagnostics of the dynamic solar chromosphere as revealed by Hinode, although this make it difficult to design the telescope because of ten times more solar heat load introduced into the telescope. The SUVIT consists of two optically separable components; the telescope assembly (TA) and an accompanying focal plane package equipped with filtergraphs and spectrographs. Opto-mechanical and -thermal performance of the TA is crucial to attain high-quality solar observations and here we present a status of feasible study in its optical and thermal designing for diffraction-limited performance at visible wavelength in a reasonably wide field of view.

  9. Combinatorial search for green and blue phosphors of high thermal stabilities under UV excitation based on the K(Sr1-x-y)PO4:Tb3+ xEu2+y system.

    Science.gov (United States)

    Chan, Ting-Shan; Liu, Yao-Min; Liu, Ru-Shi

    2008-01-01

    The present investigation aims at the synthesis of KSr 1-x-y PO 4:Tb(3+) x Eu(2+) y phosphors using the combinatorial chemistry method. We have developed square-type arrays consisting of 121 compositions to investigate the optimum composition and luminescence properties of KSrPO 4 host matrix under 365 nm ultraviolet (UV) light. The optimized compositions of phosphors were found to be KSr 0.93PO 4:Tb(3+) 0.07 (green) and KSr 0.995PO 4:Eu(2+) 0.005 (blue). These phosphors showed good thermal luminescence stability better than commercially available YAG:Ce at temperature above 200 degrees C. The result indicates that the KSr 1-x-y PO 4:Tb(3+) x Eu (2+)y can be potentially useful as a UV radiation-converting phosphor for light-emitting diodes.

  10. Severe measures for the reduction of the SO2 emissions, applicable to the thermal power plants in Romania

    International Nuclear Information System (INIS)

    Pop, Ovidiu

    2006-01-01

    The accession of Romania to EU imposes the observance of the environment community regulations and the international conventions to which Romania is a party, as well. The legislative framework was adapted to the of the community regulations by conditioning the operation of the Large Burning Units, LBU, (of thermal power larger than 50 MW) that belong to the thermal power plants. The control of the LBU operation is not limited to the technological problems but goes further to issues related to the protection of the environment where the severity of the measures adopted imposes equally the control of the Emission Limit Values, ELV. To reduce the pollutant emissions, Romania must observe the ELVs for sulfur dioxide, nitrogen oxides and aerosols for each of the existing LBU, and also to prepare a National Plant for the Reduction of the Pollutant Emissions within a transition period, thus ensuring a strict compliance with the EU regulations by January 1, 2008. The power plants for which the transition period was awarded are requested to prevent the pollution especially through the application of the best available techniques what assumes the implementation of some important investment programs. In order to have a clear image on what the observance of the community regulations mean in the domain of the sulfur dioxide emission from the LBU, a few self-evident figures are shown. The paper tackles the following issues: EU Accession Requirements; The efforts of the conforming; The best available techniques (BAT); Severe Measures for the Reduction of the Sulfur Emissions; Wet Desulfurization Procedures; Desulfurization dry/semidry procedures. Since the fuels used by the LBUs in Romania have much sulfur one concludes that they cannot be fired without the desulfurization of the flue gases. Even the mandatory utilization of the fuel oil with sulfur contents less than 1% starting by January 1, 2007 cannot solve the problem; it reduces to a certain extent the SO 2 emissions but

  11. Tunable blue-green emission and energy transfer properties in β-Ca3(PO4)2:Eu(2+), Tb(3+) phosphors with high quantum efficiencies for UV-LEDs.

    Science.gov (United States)

    Li, Kai; Zhang, Yang; Li, Xuejiao; Shang, Mengmeng; Lian, Hongzhou; Lin, Jun

    2015-03-14

    A series of Eu(2+) and Tb(3+) singly-doped and co-doped β-Ca3(PO4)2 phosphors have been synthesized via the high-temperature solid-state reaction method. Thermogravimetric (TG) analysis, fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) patterns and Rietveld refinements, photoluminescence (PL) spectra including temperature-dependent PL and quantum efficiency, and fluorescence decay lifetimes have been used to characterise the as-prepared samples. Under UV excitation, β-Ca3(PO4)2:Eu(2+) presents a broad emission band centered at 415 nm, which can be decomposed into five symmetrical bands peaking at 390, 408, 421, 435 and 511 nm based on the substitution of five kinds of Ca(2+) sites by Eu(2+) ions. β-Ca3(PO4)2:Tb(3+) shows characteristic emission lines under Tb(3+) 4f-5d transition excitation around 223 nm. In β-Ca3(PO4)2:Eu(2+), Tb(3+) phosphors, similar excitation spectra monitored at 415 and 547 nm have been observed, which illustrates the possibility of energy transfer from Eu(2+) to Tb(3+) ions. The variations in the emission spectra and decay lifetimes further demonstrate the existence of energy transfer from Eu(2+) to Tb(3+) ions under UV excitation. The energy transfer mechanism has been confirmed to be dipole-quadrupole, which can be validated via the agreement of critical distances obtained from the concentration quenching (12.11 Å) and spectrum overlap methods (9.9-13.2 Å). The best quantum efficiency can reach 90% for the β-Ca3(PO4)2:0.01Eu(2+), 0.15Tb(3+) sample under 280 nm excitation. These results show that the developed phosphors may possess potential applications in UV-pumped white light-emitting diodes.

  12. High-efficiency electroluminescence and amplified spontaneous emission from a thermally activated delayed fluorescent near-infrared emitter

    Science.gov (United States)

    Kim, Dae-Hyeon; D'Aléo, Anthony; Chen, Xian-Kai; Sandanayaka, Atula D. S.; Yao, Dandan; Zhao, Li; Komino, Takeshi; Zaborova, Elena; Canard, Gabriel; Tsuchiya, Youichi; Choi, Eunyoung; Wu, Jeong Weon; Fages, Frédéric; Brédas, Jean-Luc; Ribierre, Jean-Charles; Adachi, Chihaya

    2018-02-01

    Near-infrared organic light-emitting diodes and semiconductor lasers could benefit a variety of applications including night-vision displays, sensors and information-secured displays. Organic dyes can generate electroluminescence efficiently at visible wavelengths, but organic light-emitting diodes are still underperforming in the near-infrared region. Here, we report thermally activated delayed fluorescent organic light-emitting diodes that operate at near-infrared wavelengths with a maximum external quantum efficiency of nearly 10% using a boron difluoride curcuminoid derivative. As well as an effective upconversion from triplet to singlet excited states due to the non-adiabatic coupling effect, this donor-acceptor-donor compound also exhibits efficient amplified spontaneous emission. By controlling the polarity of the active medium, the maximum emission wavelength of the electroluminescence spectrum can be tuned from 700 to 780 nm. This study represents an important advance in near-infrared organic light-emitting diodes and the design of alternative molecular architectures for photonic applications based on thermally activated delayed fluorescence.

  13. Characteristics of ammonia emission during thermal drying of lime sludge for co-combustion in cement kilns.

    Science.gov (United States)

    Liu, Wei; Xu, Jingcheng; Liu, Jia; Cao, Haihua; Huang, Xiang-Feng; Li, Guangming

    2015-01-01

    Thermal drying was used to reduce sludge moisture content before co-combustion in cement kilns. The characteristics of ammonia (NH3) emission during thermal drying of lime sludge (LS) were investigated in a laboratory-scale tubular dry furnace under different temperature and time conditions. As the temperature increased, the NH3 concentration increased in the temperature range 100-130°C, decreased in the temperature range 130-220°C and increased rapidly at >220°C. Emission of NH3 also increased as the lime dosage increased and stabilized at lime dosages>5%. In the first 60 min of drying experiments, 55% of the NH3 was released. NH3 accounted for about 67-72% of the change in total nitrogen caused by the release of nitrogen-containing volatile compounds (VCs) from the sludge. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy revealed that the main forms of nitrogen in sludge were amides and amines. The addition of lime (CaO) could cause conversion of N-H, N-O or C-N containing compounds to NH3 during the drying process.

  14. Initiation of vacuum breakdown and failure mechanism of the carbon nanotube during thermal field emission

    Science.gov (United States)

    Dan, Cai; Lie, Liu; Jin-Chuan, Ju; Xue-Long, Zhao; Hong-Yu, Zhou; Xiao, Wang

    2016-04-01

    The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method. Project supported by the National Natural Science Foundation of China (Grant Nos. 11305263 and 61401484).

  15. The economics of reducing CO2 emissions by solar thermal power plants

    International Nuclear Information System (INIS)

    Brakmann, G.

    1993-01-01

    The necessity to reduce CO 2 -emissions on a global scale is being recognized by scientists and politicians. If no scientific proof of a climate catastrophe due to CO 2 -emissions can be established, it would nevertheless be prudent to implement a form of global survival insurance policy, the premium of which is the required effort to reduce CO 2 -emissions. The implementation of such a policy without a considerable reduction in the living standard requires the replacement of fossil fuels by capital and/or know-how. It should be performed in the most economical manner. This leads to the replacement of the classical ''least cost power expansion strategy'' by the ''least cost power expansion/pollution limiting strategy''. Thereby projects have to compete no longer exclusively on low cost of energy production but on low cost of pollution reduction as well. (Author)

  16. A comparison of the thermal, emission and heat transfer characteristics of swirl-stabilized premixed and inverse diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Zhen, H.S.; Leung, C.W.; Cheung, C.S. [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)

    2011-02-15

    Two swirl-stabilized flames, a premixed flame (PMF-s) and an inverse diffusion flame (IDF-s), were investigated experimentally in order to obtain information on their thermal, emission and heat transfer characteristics. The two flames, having different global air/fuel mixing mechanisms, were compared under identical air and fuel flow rates. Results showed that the two flames have similar visual features such as flame shape, size and structure because the Reynolds number and the swirl number which are important parameters representative of the aerodynamic characteristics of a swirling jet flow, are almost the same for the two flames. The minor dissimilarity in flame color and flame length indicates that the IDF-s is more diffusional. Both the PMF-s and IDF-s are stabilized by the internal recirculation zone (IRZ) and the IDF-s is more stable. Flame temperature is uniformly distributed in the IRZ due to the strong mixing caused by flow recirculation. The highest flame temperature is achieved at the main reaction zone and it is higher for the PMF-s due to more rapid and localized heat release. For the IDF-s, the thermal NO mechanism dominates the NO{sub x} formation. For the PMF-s, both the thermal and prompt mechanisms tend to play important roles in the global NO{sub x} emission under rich conditions. The comparison of EINO{sub x} and EICO shows that the PMF-s has lower level of NO{sub x} emission under lean combustion and lower level of CO emission under all conditions. The reason is that the air/fuel premixing in the PMF-s significantly enhances the mixedness of the supplied air/fuel mixture. The analysis of the behaviors of the impinging PMF-s and IDF-s heat transfer reveals that because the PMF-s has more rapid and localized heat release at the main reaction zone, the peak heat flux is higher than that of the IDF-s and the IDF-s has more uniform heating effect. A comparison of the overall heat transfer rates shows that, due to more complete combustion, the PMF

  17. A comparison of the thermal, emission and heat transfer characteristics of swirl-stabilized premixed and inverse diffusion flames

    International Nuclear Information System (INIS)

    Zhen, H.S.; Leung, C.W.; Cheung, C.S.

    2011-01-01

    Two swirl-stabilized flames, a premixed flame (PMF-s) and an inverse diffusion flame (IDF-s), were investigated experimentally in order to obtain information on their thermal, emission and heat transfer characteristics. The two flames, having different global air/fuel mixing mechanisms, were compared under identical air and fuel flow rates. Results showed that the two flames have similar visual features such as flame shape, size and structure because the Reynolds number and the swirl number which are important parameters representative of the aerodynamic characteristics of a swirling jet flow, are almost the same for the two flames. The minor dissimilarity in flame color and flame length indicates that the IDF-s is more diffusional. Both the PMF-s and IDF-s are stabilized by the internal recirculation zone (IRZ) and the IDF-s is more stable. Flame temperature is uniformly distributed in the IRZ due to the strong mixing caused by flow recirculation. The highest flame temperature is achieved at the main reaction zone and it is higher for the PMF-s due to more rapid and localized heat release. For the IDF-s, the thermal NO mechanism dominates the NO x formation. For the PMF-s, both the thermal and prompt mechanisms tend to play important roles in the global NO x emission under rich conditions. The comparison of EINO x and EICO shows that the PMF-s has lower level of NO x emission under lean combustion and lower level of CO emission under all conditions. The reason is that the air/fuel premixing in the PMF-s significantly enhances the mixedness of the supplied air/fuel mixture. The analysis of the behaviors of the impinging PMF-s and IDF-s heat transfer reveals that because the PMF-s has more rapid and localized heat release at the main reaction zone, the peak heat flux is higher than that of the IDF-s and the IDF-s has more uniform heating effect. A comparison of the overall heat transfer rates shows that, due to more complete combustion, the PMF-s has higher overall

  18. Experimental investigation of combustion, emissions and thermal balance of secondary butyl alcohol-gasoline blends in a spark ignition engine

    International Nuclear Information System (INIS)

    Yusri, I.M.; Mamat, Rizalman; Azmi, W.H.; Najafi, G.; Sidik, N.A.C.; Awad, Omar I.

    2016-01-01

    Highlights: • 2-Butanol-gasoline blends up to 15% of volume were examined. • Combustion emissions and thermal balance for blended fuel were discussed. • Significant of improvement for energy utilisation by using blended fuels. - Abstract: An experimental investigation of butanol as an alternative fuel was conducted. A four-cylinder, four-stroke gasoline engine was used to investigate the engine combustion emissions and thermal balance characteristics using 2-butanol–gasoline blended fuels at 50% throttle wide open. In this experimental study, the gasoline engine was tested at 2-butanol–gasoline percentage volume ratios of 5:95 (GBu5), 10:90 (GBu10) and 15:85 (GBu15) of gasoline to butanol, respectively. Combustion analysis results showed that 2-butanol–gasoline blends have a lower in-cylinder pressure, rate of pressure rise and rate of heat release. However, as the 2-butanol addition increases in the blended fuels, increasing trends of in-cylinder pressure, rate of pressure rise and rate of heat release are observed, but it is still lower than G100 fuels. Moreover, even 5%, 10% and 15% additions of 2-butanol in the gasoline fuels improve the COV of IMEP by 3.7, 3.46 and 3.26, respectively, which indicates that the presence of 2-butanol stabilises the combustion process. Comparative analysis of the experimental results by exhaust emissions produced an average of 7.1%, 13.7%, and 19.8% lower NO_x for GBu5, GBu10 and GBu15, respectively, over the speed range of 1000–4000 RPM. Other emission contents indicate lower CO and HC but higher CO_2 from 2500 to 4000 RPM for the blended fuels with regard to G100. The thermal balance analysis mainly exhibits an improvement in effective power, cooling energy and exhaust energy by average differences of 3.3%, 0.8% and 2.3% for GBu15 compared with G100.

  19. Elevated [CO2] magnifies isoprene emissions under heat and improves thermal resistance in hybrid aspen

    OpenAIRE

    Sun, Zhihong; H?ve, Katja; Vislap, Vivian; Niinemets, ?lo

    2013-01-01

    Isoprene emissions importantly protect plants from heat stress, but the emissions become inhibited by instantaneous increase of [CO2], and it is currently unclear how isoprene-emitting plants cope with future more frequent and severe heat episodes under high [CO2]. Hybrid aspen (Populus tremula x Populus tremuloides) saplings grown under ambient [CO2] of 380 ?mol mol?1 and elevated [CO2] of 780 ?mol mol?1 were used to test the hypothesis that acclimation to elevated [CO2] reduces the inhibito...

  20. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

    The use of synchrotron radiation (SR) in the ultraviolet (UV) region by biophysics and biophysical chemists continues to increase as access improves and as awareness of its unique combination of properties grows. SR is continuously tunable, intense (even in the UV region), and pulsed. Pulse characteristics are comparable to those of picosecond lasers, but have the advantage of being independent of wavelength. Drawbacks are the continuous, but slow, decay of intensity arising from loss of particles in the ring, and the intrinsic limitation in pulse repetition rate. The particular combination of features that makes SR a superior light source depends upon the application. Spectroscopic techniques based on absorption and some techniques based on emission exploit its intensity and continuous tunability; time resolved techniques make use of its pulse characteristics. This chapter is a status report on two of the major biological applications of UV SR, circular dichroism and time-resolved fluorescence, covering mainly the published literature of the last five years. For the present purpose, the term UV is understood to include the vacuum ultraviolet region to 100 nm. (author). 83 refs.; 4 figs.; 6 tabs

  1. An inexpensive and simple method for thermally stable immobilization of DNA on an unmodified glass surface: UV linking of poly(T)10-poly(C)10-tagged DNA probes

    DEFF Research Database (Denmark)

    Guðnason, Haukur; Dufva, Hans Martin; Bang, Dang Duong

    2008-01-01

    be linked by UV light irradiation onto a plain, unmodified glass surface. Probes immobilized onto unmodified glass microscope slides performed similarly to probes bound to commercial amino-silane-coated slides and had comparable detection limits. The TC-tagged probes linked to unmodified glass did not show...... any significant decrease in hybridization performance after a 20 min incubation in water at 100 degrees C prior to rehybridization, indicating a covalent bond between the TC tag and unmodified glass. The probes were used in thermal minisequencing cycling reactions. Furthermore, the TC tag improved...

  2. Enhanced light emission efficiency and current stability by morphology control and thermal annealing of organic light emitting diode devices

    Energy Technology Data Exchange (ETDEWEB)

    Caria, S [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P Gobetti 101, 40129 Bologna (Italy); Como, E Da [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P Gobetti 101, 40129 Bologna (Italy); Murgia, M [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P Gobetti 101, 40129 Bologna (Italy); Zamboni, R [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P Gobetti 101, 40129 Bologna (Italy); Melpignano, P [Centro Ricerche Plast-Optica (CRP), via Jacopo Linussio 1, 33020 Amaro (UD) (Italy); Biondo, V [Centro Ricerche Plast-Optica (CRP), via Jacopo Linussio 1, 33020 Amaro (UD) (Italy)

    2006-08-23

    The electro-optical behaviour of organic light emitting diode devices (OLEDs) is greatly influenced by the morphology of the films. A major parameter is due to the important role that the morphology of the active organic thin films plays in the phenomena that lead to light emission. For vacuum-grown OLEDs, the morphology of the specific thin films can be varied by modification of the deposition conditions. We have assessed the method (ultrahigh-vacuum organic molecular beam deposition) and conditions (variation of the deposition rate) for electro-emission (EL) optimization in a standard {alpha}-NPB (N,N'-bis-(1-naphthyl)-N,N' diphenyl-1,1' biphenyl-4-4' diamine)/Alq3 (tris-(8-hydroxyquinoline) aluminium) vacuum-grown OLED device. The best EL performances have been obtained for OLEDs made in ultrahigh vacuum with the Alq3 layer deposited with a differential deposition rate ranging from 1.0 to 0.3Angsts{sup -1}. The results are consistent with a model of different Alq3 morphologies, allowing efficient charge injection at the metal/organic interface, and of the minimization of grain boundaries at the electron-hole recombination interface, allowing efficient radiative excitonic decay. At the same time, with the objective of controlling and stabilizing the morphology changes and stabilizing the charge transport over a long OLED operating time, we have studied the effect of thermal annealing processing in the standard current behaviour of OLEDs. The large current fluctuations typically observed for standard vacuum-grown OLEDs have been smeared out and kept constant over a long operating time by the given thermal annealing conditions. The results are interpreted in terms of the stabilization of intrinsic polymorphism of the organic film's structure induced by thermal energy and leading the morphology to a lowest-energetic configuration.

  3. The role of Dark Matter sub-halos in the non-thermal emission of galaxy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Marchegiani, Paolo; Colafrancesco, Sergio, E-mail: Paolo.Marchegiani@wits.ac.za, E-mail: Sergio.Colafrancesco@wits.ac.za [School of Physics, University of the Witwatersrand, Private Bag 3, WITS-2050, Johannesburg (South Africa)

    2016-11-01

    Annihilation of Dark Matter (DM) particles has been recognized as one of the possible mechanisms for the production of non-thermal particles and radiation in galaxy clusters. Previous studies have shown that, while DM models can reproduce the spectral properties of the radio halo in the Coma cluster, they fail in reproducing the shape of the radio halo surface brightness because they produce a shape that is too concentrated towards the center of the cluster with respect to the observed one. However, in previous studies the DM distribution was modeled as a single spherically symmetric halo, while the DM distribution in Coma is found to have a complex and elongated shape. In this work we calculate a range of non-thermal emissions in the Coma cluster by using the observed distribution of DM sub-halos. We find that, by including the observed sub-halos in the DM model, we obtain a radio surface brightness with a shape similar to the observed one, and that the sub-halos boost the radio emission by a factor between 5 and 20%, thus allowing to reduce the gap between the annihilation cross section required to reproduce the radio halo flux and the upper limits derived from other observations, and that this gap can be explained by realistic values of the boosting factor due to smaller substructures. Models with neutralino mass of 9 GeV and composition τ{sup +} τ{sup −}, and mass of 43 GeV and composition b b-bar can fit the radio halo spectrum using the observed properties of the magnetic field in Coma, and do not predict a gamma-ray emission in excess compared to the recent Fermi-LAT upper limits. These findings make these DM models viable candidate to explain the origin of radio halos in galaxy clusters, avoiding the problems connected to the excessive gamma-ray emission expected from proton acceleration in most of the currently proposed models, where the acceleration of particles is directly or indirectly connected to events related to clusters merging. Therefore, DM

  4. Controlling the diameters and field emission properties of vertically aligned carbon nanotubes synthesized by thermal chemical vapor deposition

    International Nuclear Information System (INIS)

    Choi, Sung Yool; Kang, Young Il; Cho, Kyoung Ik; Choi, Kyu Seok; Kim, Do Jin

    2001-01-01

    We report here the synthesis of vertically well-aligned carbon nanotubes and the effect of catalytic metal layer on the diameter of grown carbon nanotubes and the field emission characteristics of them, The carbon nanotubes were grown by thermal chemical vapor deposition at temperatures below 900 .deg. C on Fe metal catalytic layer, deposited by sputtering process on a Si substrate and pretreated by heat and NH 3 gas. We found that the thickness of metal layers could be an important parameter in controlling the diameters of carbon nanotubes. With varying the thickness of the metal layers the grain sizes of them also vary so that the diameters of the nanotubes could be controlled. Field emission measurement has been made on the carbon nanotube field emitters at room temperature in a vacuum chamber below 10 -6 Torr. Our vertically aligned carbon nanotube field emitter of the smallest diameter emits a current density about 10 mA/cm 2 at 7.2 V/μm. The field emission property of the carbon nanotubes shows strong dependence on the nanotube diameters as expected

  5. Amended Results for Hard X-Ray Emission by Non-thermal Thick Target Recombination in Solar Flares

    Science.gov (United States)

    Reep, J. W.; Brown, J. C.

    2016-06-01

    Brown & Mallik and the corresponding corrigendum Brown et al. presented expressions for non-thermal recombination (NTR) in the collisionally thin- and thick-target regimes, claiming that the process could account for a substantial part of the hard X-ray continuum in solar flares usually attributed entirely to thermal and non-thermal bremsstrahlung (NTB). However, we have found the thick-target expression to become unphysical for low cut-offs in the injected electron energy spectrum. We trace this to an error in the derivation, derive a corrected version that is real-valued and continuous for all photon energies and cut-offs, and show that, for thick targets, Brown et al. overestimated NTR emission at small photon energies. The regime of small cut-offs and large spectral indices involve large (reducing) correction factors but in some other thick-target parameter regimes NTR/NTB can still be of the order of unity. We comment on the importance of these results to flare and microflare modeling and spectral fitting. An empirical fit to our results shows that the peak NTR contribution comprises over half of the hard X-ray signal if δ ≳ 6{≤ft(\\tfrac{{E}0c}{4{keV}}\\right)}0.4.

  6. How the geysers, tidal stresses, and thermal emission across the south polar terrain of enceladus are related

    International Nuclear Information System (INIS)

    Porco, Carolyn; DiNino, Daiana; Nimmo, Francis

    2014-01-01

    We present the first comprehensive examination of the geysering, tidal stresses, and anomalous thermal emission across the south pole of Enceladus and discuss the implications for the moon's thermal history and interior structure. A 6.5 yr survey of the moon's south polar terrain (SPT) by the Cassini imaging experiment has located ∼100 jets or geysers erupting from four prominent fractures crossing the region. Comparing these results with predictions of diurnally varying tidal stresses and with Cassini low resolution thermal maps shows that all three phenomena are spatially correlated. The coincidence of individual jets with very small (∼10 m) hot spots detected in high resolution Cassini VIMS data strongly suggests that the heat accompanying the geysers is not produced by shearing in the upper brittle layer but rather is transported, in the form of latent heat, from a sub-ice-shell sea of liquid water, with vapor condensing on the near-surface walls of the fractures. Normal stresses modulate the geysering activity, as shown in the accompanying paper; we demonstrate here they are capable of opening water-filled cracks all the way down to the sea. If Enceladus' eccentricity and heat production are in steady state today, the currently erupting material and anomalous heat must have been produced in an earlier epoch. If regional tidal heating is occurring today, it may be responsible for some of the erupting water and heat. Future Cassini observations may settle the question.

  7. Non-thermal emission in the core of Perseus: results from a long XMM-Newton observation

    Science.gov (United States)

    Molendi, S.; Gastaldello, F.

    2009-01-01

    We employ a long XMM-Newton observation of the core of the Perseus cluster to validate claims of a non-thermal component discovered with Chandra. From a meticulous analysis of our dataset, which includes a detailed treatment of systematic errors, we find the 2-10 keV surface brightness of the non-thermal component to be less than about 5 × 10-16 erg~cm-2 s-1 arcsec-2. The most likely explanation for the discrepancy between the XMM-Newton and Chandra estimates is a problem in the effective area calibration of the latter. Our EPIC-based magnetic field lower limits do not disagree with Faraday rotation measure estimates on a few cool cores and with a minimum energy estimate on Perseus. In the not too distant future Simbol-X may allow detection of non-thermal components with intensities more than 10 times lower than those that can be measured with EPIC; nonetheless even the exquisite sensitivity within reach for Simbol-X might be insufficient to detect the IC emission from Perseus.

  8. The Analysis of the Possible Thermal Emission at Radio Frequencies from an Evolved Supernova Remnant HB 3 (G132.7+1.3: Revisited

    Directory of Open Access Journals (Sweden)

    Onić, D.

    2008-12-01

    Full Text Available It has recently been reported that some of the flux density values for an evolved supernova remnant (SNR HB 3 (G132.7$+$1.3 are not accurate enough. In this work we therefore revised the analysis of the possible thermal emission at radio frequencies from this SNR using the recently published, corrected flux density values. A model including the sum of non-thermal (purely synchrotron and thermal (bremsstrahlung components is applied to fit the integrated radio spectrum of this SNR. The contribution of thermal component to the total volume emissivity at $1 mathrm{GHz}$ is estimated to be $approx37 \\%$. The ambient density is also estimated to be $napprox 9 mathrm{cm}^{-3}$ for $mathrm{T}=10^{4} mathrm{K}$. Again we obtained a relatively significant presence of thermal emission at radio frequencies from the SNR, which can support interaction between SNR HB 3 and adjacent molecular cloud associated with the mbox{H,{sc ii}} region W3. Our model estimates for thermal component contribution to total volume emissivity at $1 mathrm{GHz}$ and ambient density are similar to those obtained earlier ($approx40 \\%$, $approx10 mathrm{cm^{-3}}$. It is thus obvious that the corrected flux density values do not affect the basic conclusions.

  9. Reduction of heat losses from greenhouses by means of internal blinds with low thermal emissivity

    NARCIS (Netherlands)

    Meijer, J.

    1980-01-01

    Heat losses in greenhouses may be substantially reduced by the use of heat reflecting blinds. Quantitative results are obtained solving a mathematical heat flow model by numerical methods. Special attention has been given to the emissivity and transmittance of the screen and the ventilation through

  10. Planck 2013 results. XI. All-sky model of thermal dust emission

    DEFF Research Database (Denmark)

    Abergel, A.; Ade, P. A. R.; Aghanim, N.

    2014-01-01

    This paper presents an all-sky model of dust emission from the Planck 353, 545, and 857 GHz, and IRAS 100 mu m data. Using a modified blackbody fit to the data we present all-sky maps of the dust optical depth, temperature, and spectral index over the 353-3000 GHz range. This model is a good repr...

  11. Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust

    DEFF Research Database (Denmark)

    Cardoso, J. F.; Delabrouille, J.; Ganga, K.

    2015-01-01

    measurements toward extragalactic sources. These components bear resemblance along the Galactic plane and in some regions such as the Fan and North Polar Spur regions. The poor match observed in other regions shows, however, that dust, cosmic-ray electrons, and thermal electrons generally sample different...

  12. Influence of interconnection on the long-term reliability of UV LED packages

    Science.gov (United States)

    Nieland, S.; Mitrenga, D.; Karolewski, D.; Brodersen, O.; Ortlepp, T.

    2017-02-01

    High power LEDs have conquered the mass market in recent years. Besides the main development focus to achieve higher productivity in the field of visible semiconductor LED processing, the wavelength range is further enhanced by active research and development in the direction of UVA / UVB / UVC. UVB and UVC LEDs are new and promising due to their numerous advantages. UV LEDs emit in a near range of one single emission peak with a width (FWHM) below 15 nm compared to conventional mercury discharge lamps and xenon sources, which show broad spectrums with many emission peaks over a wide range of wavelengths. Furthermore, the UV LED size is in the range of a few hundred microns and offers a high potential of significant system miniaturization. Of course, LED efficiency, lifetime and output power have to be increased [1]. Lifetime limiting issues of UVB/UVC-LED are the very high thermal stress in the chip resulting from the higher forward voltages (6-10 V @ 350 mA), the lower external quantum efficiency, below 10 % (most of the power disappears as heat), and the thermal resistance Rth of conventional LED packages being not able to dissipate these large amounts of heat for spreading. Beside the circuit boards and submounts which should have maximum thermal conductivity, the dimension of contacts as well as the interconnection of UV LED to the submount/package determinates the resolvable amount of heat [2]. In the paper different innovative interconnection techniques for UVC-LED systems will be discussed focused on the optimization of thermal conductivity in consideration of the assembly costs. Results on thermal simulation for the optimal contact dimensions and interconnections will be given. In addition, these theoretical results will be compared with results on electrical characterization as well as IR investigations on real UV LED packages in order to give recommendations for optimal UV LED assembly.

  13. Effect of Molecular Guest Binding on the d-d Transitions of Ni2+ of CPO-27-Ni: A Combined UV-Vis, Resonant-Valence-to-Core X-ray Emission Spectroscopy, and Theoretical Study.

    Science.gov (United States)

    Gallo, Erik; Gorelov, Evgeny; Guda, Alexander A; Bugaev, Aram L; Bonino, Francesca; Borfecchia, Elisa; Ricchiardi, Gabriele; Gianolio, Diego; Chavan, Sachin; Lamberti, Carlo

    2017-12-04

    We used Ni K-edge resonant-valence-to-core X-ray emission spectroscopy (RVtC-XES, also referred to as direct RIXS), an element-selective bulk-sensitive synchrotron-based technique, to investigate the electronic structure of the CPO-27-Ni metal-organic framework (MOF) upon molecular adsorption of significant molecular probes: H 2 O, CO, H 2 S, and NO. We compare RVtC-XES with UV-vis spectroscopy, and we show that the element selectivity of RVtC-XES is of strategic significance to observe the full set of d-d excitations in Ni 2+ , which are partially overshadowed by the low-energy π-π* transitions of the Ni ligands in standard diffuse-reflectance UV-vis experiments. Our combined RVtC-XES/UV-vis approach provides access to the whole set of d-d excitations, allowing us a complete discussion of the changes undergone by the electronic configuration of the Ni 2+ sites hosted within the MOF upon molecular adsorption. The experimental data have been interpreted by multiplet ligand-field theory calculations based on Wannier orbitals. This study represents a step further in understanding the ability of the CPO-27-Ni MOFs in molecular sorption and separation applications.

  14. Computational fluid dynamics (CFD) simulation of CO2 emission from a thermal power plant in an urban environment.

    Science.gov (United States)

    Toja-Silva, Francisco; Chen, Jia; Hachinger, Stephan

    2017-04-01

    Climate change, a societal challenge for the European Union, is affecting all regions in Europe and has a profound impact on society and environment. It is now clear that the present global warming period is due to the strong anthropogenic greenhouse gas (GHG) emission, occurring at an unprecedented rate. Therefore, the identification and control of the greenhouse gas sources has a great relevance. Since the GHG emissions from cities are the largest human contribution to climate change, the present investigation focuses on the urban environment. Bottom-up annual emission inventories are compiled for most countries. However, a rigorous approach requires to perform experimental measurements in order to verify the official estimates. Measurements of column-averaged dry-air mole fractions of GHG (XGHG) can be used for this. To comprehensively detect and quantify GHG emission sources, these punctual column data, however, have to be extended to the surrounding urban map, requiring a deep understanding of the gas transport. The resulting emission estimation will serve several practical purposes, e.g. the verification of official emission rates and the determination of trends in urban emissions. They will enable the administration to make targeted and economically efficient decisions about mitigation options, and help to stop unintentional and furtive releases. With this aim, this investigation presents a completely new approach to the analysis of the carbon dioxide (CO2) emissions from fossil fuel thermal power plants in urban environments by combining differential column measurements with computational fluid dynamics (CFD) simulations in order to deeply understand the experimental conditions. The case study is a natural gas-fueled cogeneration (combined heat and power, CHP) thermal power plant inside the city of Munich (Germany). The software used for the simulations (OpenFOAM) was modified in order to use the most advanced RANS turbulence modeling (i.e. Durbin) and

  15. Formation of the UV Spectrum of Molecular Hydrogen in the Sun

    Science.gov (United States)

    Jaeggli, S. A.; Judge, P. G.; Daw, A. N.

    2018-03-01

    Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.

  16. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  17. Impurity line emission due to thermal charge exchange in JET edge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maggi, C F; Horton, L D; Koenig, R; Stamp, M [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Summers, H P [Strathclyde Univ., Glasgow (United Kingdom)

    1994-07-01

    High n-shell emission from hydrogen-like carbon (C VI, n=8-7) has been routinely observed from the plasma edge of JET. By comparing the measured spectral line intensities with the signals predicted by advanced atomic physics modelling of carbon and hydrogen radiation, integrated with modelling of the divertor and edge plasma, it is concluded that charge transfer from excited state hydrogen donors into fully stripped carbon ions can account for the observed spectral emission, but that the hydrogen distribution and to a lesser extent the carbon distribution away from the strike zone predicted by the transport model are too low. Data presented are those of three upper X-point discharges, where the target material was carbon. 5 refs., 1 fig., 3 tabs.

  18. Planck intermediate results. XXII. Frequency dependence of thermal emission from Galactic dust in intensity and polarization

    DEFF Research Database (Denmark)

    Cardoso, J. F.; Delabrouille, J.; Ganga, K.

    2015-01-01

    )% from 353 to 70 GHz. We discuss this result within the context of existing dust models. The decrease in p could indicate differences in polarization efficiency among components of interstellar dust (e.g., carbon versus silicate grains). Our observational results provide inputs to quantify and optimize......Planck has mapped the intensity and polarization of the sky at microwave frequencies with unprecedented sensitivity. We use these data to characterize the frequency dependence of dust emission. We make use of the Planck 353 GHz I, Q, and U Stokes maps as dust templates, and cross-correlate them...... of the cosmic microwave background. We use a mask that focuses our analysis on the diffuse interstellar medium at intermediate Galactic latitudes. We determine the spectral indices of dust emission in intensity and polarization between 100 and 353 GHz, for each sky patch. Both indices are found to be remarkably...

  19. Emission reduction in thermal processes for sewage sludge disposal; Emissionsreduzierung bei thermischen Verfahren zur Klaerschlammentsorgung

    Energy Technology Data Exchange (ETDEWEB)

    Nethe, L.P. [Maerker Umwelttechnik GmbH, Hamburg (Germany)

    1998-09-01

    Owing to the intensification of treatment processes and the construction of new sewage plants sewage arisings are due to rise considerably. The thermal treatment of sewage sludge which it has not been possible to avoid or utilise is an important and indispensable part of any sewage sludge disposal concept. If equipped with a state-of-the-art flue gas purification process that uses carbonaceous adsorbents (Sorbalit trademark), thermal treatment of sewage sludge can be regarded as an environmentally safe process technique. [Deutsch] Die anfallenden Klaerschlammengen werden durch die Intensivierung der Klaerprozesse und der Bau neuer Klaeranlagen deutlich zunehmen. Die thermische Behandlung nicht vermiedener oder verwerteter Klaerschlaemme stellt einen bedeutenden und unverzichtbaren Teil der Klaerschlamm-Entsorgungskonzepte dar. Bei Installation einer - dem Stand der Technik - entsprechenden Rauchgasreinigung mit dem Einsatz kohlenstoffhaltiger Adsorbentien (Sorbalit {sup trademark}) ist die thermische Behandlung von Klaerschlamm eine umweltsichere Verfahrenstechnik. (orig.)

  20. Thermal tuning of spectral emission from optically trapped liquid-crystal droplet resonators

    Czech Academy of Sciences Publication Activity Database

    Jonáš, A.; Pilát, Zdeněk; Ježek, Jan; Bernatová, Silvie; Fořt, Tomáš; Zemánek, Pavel; Aas, M.; Kiraz, A.

    2017-01-01

    Roč. 34, č. 9 (2017), s. 1855-1864 ISSN 0740-3224 R&D Projects: GA MŠk(CZ) LD14069; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : emission spectroscopy * drops * optical tweezers Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.843, year: 2016

  1. Impact Analysis of Air Pollutant Emission Policies on Thermal Coal Supply Chain Enterprises in China

    OpenAIRE

    Xiaopeng Guo; Xiaodan Guo; Jiahai Yuan

    2014-01-01

    Spurred by the increasingly serious air pollution problem, the Chinese government has launched a series of policies to put forward specific measures of power structure adjustment and the control objectives of air pollution and coal consumption. Other policies pointed out that the coal resources regional blockades will be broken by improving transportation networks and constructing new logistics nodes. Thermal power takes the largest part of China’s total installed power generation capacity, s...

  2. Improving the accuracy of S02 column densities and emission rates obtained from upward-looking UV-spectroscopic measurements of volcanic plumes by taking realistic radiative transfer into account

    Science.gov (United States)

    Kern, Christoph; Deutschmann, Tim; Werner, Cynthia; Sutton, A. Jeff; Elias, Tamar; Kelly, Peter J.

    2012-01-01

    Sulfur dioxide (SO2) is monitored using ultraviolet (UV) absorption spectroscopy at numerous volcanoes around the world due to its importance as a measure of volcanic activity and a tracer for other gaseous species. Recent studies have shown that failure to take realistic radiative transfer into account during the spectral retrieval of the collected data often leads to large errors in the calculated emission rates. Here, the framework for a new evaluation method which couples a radiative transfer model to the spectral retrieval is described. In it, absorption spectra are simulated, and atmospheric parameters are iteratively updated in the model until a best match to the measurement data is achieved. The evaluation algorithm is applied to two example Differential Optical Absorption Spectroscopy (DOAS) measurements conducted at Kilauea volcano (Hawaii). The resulting emission rates were 20 and 90% higher than those obtained with a conventional DOAS retrieval performed between 305 and 315 nm, respectively, depending on the different SO2 and aerosol loads present in the volcanic plume. The internal consistency of the method was validated by measuring and modeling SO2 absorption features in a separate wavelength region around 375 nm and comparing the results. Although additional information about the measurement geometry and atmospheric conditions is needed in addition to the acquired spectral data, this method for the first time provides a means of taking realistic three-dimensional radiative transfer into account when analyzing UV-spectral absorption measurements of volcanic SO2 plumes.

  3. A two component model for thermal emission from organic grains in Comet Halley

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1988-01-01

    Observations of Comet Halley in the near infrared reveal a triple-peaked emission feature near 3.4 micrometer, characteristic of C-H stretching in hydrocarbons. A variety of plausible cometary materials exhibit these features, including the organic residue of irradiated candidate cometary ices (such as the residue of irradiated methane ice clathrate, and polycyclic aromatic hydrocarbons. Indeed, any molecule containing -CH3 and -CH2 alkanes will emit at 3.4 micrometer under suitable conditions. Therefore tentative identifications must rest on additional evidence, including a plausible account of the origins of the organic material, a plausible model for the infrared emission of this material, and a demonstration that this conjunction of material and model not only matches the 3 to 4 micrometer spectrum, but also does not yield additional emission features where none is observed. In the case of the residue of irradiated low occupancy methane ice clathrate, it is argued that the lab synthesis of the organic residue well simulates the radiation processing experienced by Comet Halley.

  4. MODELING THE THERMAL DIFFUSE SOFT AND HARD X-RAY EMISSION IN M17

    International Nuclear Information System (INIS)

    Velázquez, P. F.; Rodríguez-González, A.; Esquivel, A.; Rosado, M.; Reyes-Iturbide, J.

    2013-01-01

    We present numerical models of very young wind driven superbubbles. The parameters chosen for the simulations correspond to the particular case of the M17 nebula, but are appropriate for any young superbubble in which the wind sources have not completely dispersed their parental cloud. From the simulations, we computed the diffuse emission in the soft ([0.5-1.5] keV) and hard ([1.5-5] keV) X-ray bands. The total luminosity in our simulations agrees with the observations of Hyodo et al., about two orders of magnitude below the prediction of the standard model of Weaver et al.. The difference with respect to the standard (adiabatic) model is the inclusion of radiative cooling, which is still important in such young bubbles. We show that for this type of object the diffuse hard X-ray luminosity is significant compared to that of soft X-rays, contributing as much as 10% of the total luminosity, in contrast with more evolved bubbles where the hard X-ray emission is indeed negligible, being at least four orders of magnitude lower than the soft X-ray emission.

  5. Building unique surface structure on aramid fibers through a green layer-by-layer self-assembly technique to develop new high performance fibers with greatly improved surface activity, thermal resistance, mechanical properties and UV resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lifang; Yuan, Li; Guan, Qingbao; Gu, Aijuan, E-mail: ajgu@suda.edu.cn; Liang, Guozheng, E-mail: lgzheng@suda.edu.cn

    2017-07-31

    Highlights: • A green technology is setup to build unique surface structure on aramid fiber (AF). • The method is layer-by-layer self-assembling SiO{sub 2} and layered double hydroxide. • The surface of AF is adjustable by controlling the self-assembly cycle number. • New AF has excellent surface activity, anti-UV, thermal and mechanical properties. • The origin behind attractive performances of new AFs was intensively studied. - Abstract: Combining green preparation and high performance is becoming the direction of sustainable development of materials. How to simultaneously overcome the two bottlenecks (poor surface activity and UV resistance) of aramid fibers (AFs) while improving thermal and mechanical properties through a green process is still an interesting issue with big challenge. Herein, new AFs (BL-AFs) were prepared by alternately self-assembling SiO{sub 2} and MgAlFe layered double hydroxide (LDH) on surfaces of AFs, successively, through a green layer-by-layer (LBL) self-assembly technique without using high temperature and organic solvent. The structures and properties of BL-AFs were systematically studied, which are controllable by adjusting the number of self-assembly cycle. The new fibers with three or more self-assembly cycles have remarkably improved surface activity, thermal resistance, mechanical properties and UV resistance compared with AFs. Typically, with three self-assembly cycles, the initial degradation temperature and char yield of the new fiber (3BL-AF) are as high as 552.9 °C and 81.2%, about 92 °C and 25.2% higher than those of AF, respectively; after 168 h-UV irradiation, the retention of tensile performances of 3BL-AF fiber is as high as 91–95%, about 29–14% higher than that of AF, showing the best overall performances among all modified AFs prepared using a green technique reported so far. The origin behind the attractive performances of BL-AFs is revealed through correlating with structures of original and

  6. Measurement of CO{sub 2}, CO, SO{sub 2}, and NO emissions from coal-based thermal power plants in India

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, N.; Mukheriee, I.; Santra, A.K.; Chowdhury, S.; Chakraborty, S.; Bhattacharya, S.; Mitra, A.P.; Sharma, C. [Jadavpur University, Calcutta (India). Dept. of Power Engineering

    2008-02-15

    Measurements of CO{sub 2} (direct GHG) and CO, SO{sub 2}, NO (indirect GHGs) were conducted on-line at some of the coal-based thermal power plants in India. The objective of the study was three-fold: to quantify the measured emissions in terms of emission coefficient per kg of coal and per kWh of electricity, to calculate the total possible emission from Indian thermal power plants, and subsequently to compare them with some previous studies. Instrument IMR 2800P Flue Gas Analyzer was used on-line to measure the emission rates Of CO{sub 2}, CO, SO{sub 2}, and NO at 11 numbers of generating units of different ratings. Certain quality assurance (QA) and quality control (QC) techniques were also adopted to gather the data so as to avoid any ambiguity in subsequent data interpretation. For the betterment of data interpretation, the requisite statistical parameters (standard deviation and arithmetic mean) for the measured emissions have been also calculated. The emission coefficients determined for CO{sub 2}, CO, SO{sub 2}, and NO have been compared with their corresponding values as obtained in the studies conducted by other groups. The total emissions of CO{sub 2}, CO, SO{sub 2}, and NO calculated on the basis of the emission coefficients for the year 2003-2004 have been found to be 465.667, 1.583, 4.058, and 1.129 Tg, respectively.

  7. Global Thermal Power Plants Database: Unit-Based CO2, SO2, NOX and PM2.5 Emissions in 2010

    Science.gov (United States)

    Tong, D.; Qiang, Z.; Davis, S. J.

    2016-12-01

    There are more than 30,000 thermal power plants now operating worldwide, reflecting a tremendously diverse infrastructure that includes units burning oil, natural gas, coal and biomass and ranging in capacity from 1GW. Although the electricity generated by this infrastructure is vital to economic activities across the world, it also produces more CO2 and air pollution emissions than any other industry sector. Here we present a new database of global thermal power-generating units and their emissions as of 2010, GPED (Global Power Emissions Database), including the detailed unit information of installed capacity, operation year, geographic location, fuel type and control measures for more than 70000 units. In this study, we have compiled, combined, and harmonized the available underlying data related to thermal power-generating units (e.g. eGRID of USA, CPED of China and published Indian power plants database), and then analyzed the generating capacity, capacity factor, fuel type, age, location, and installed pollution-control technology in order to determine those units with disproportionately high levels of emissions. In total, this work is of great importance for improving spatial distribution of global thermal power plants emissions and exploring their environmental impacts at global scale.

  8. Is there a difference between the energy and CO_2 emission performance for China’s thermal power industry? A bootstrapped directional distance function approach

    International Nuclear Information System (INIS)

    Duan, Na; Guo, Jun-Peng; Xie, Bai-Chen

    2016-01-01

    Highlights: • Evaluate the energy and CO_2 emission performance of China’s thermal power industry. • Perform statistical inferences for the estimates of efficiency and productivity indexes. • There exist differences between the energy and CO_2 emission performance. • Technological progress is the main driving force for productivity improvement. - Abstract: A scientific evaluation of the energy efficiency and CO_2 emission performance of the thermal power industry could not only provide valuable information for reducing energy consumption and carbon emissions but also serve as a tool to estimate the effectiveness of relevant policy reforms. Considering the opposite effects of energy conservation and carbon emission reduction on generation cost, this study respectively measures the energy and CO_2 emission performance of the thermal power industries in China’s 30 provincial administrative regions during the period 2005–2012 from both static and dynamic perspectives. We implement the bootstrap method for the directional distance function to correct the possible estimate bias and test the significance of productivity changes where the weak disposability of undesirable outputs is also integrated. The empirical analysis leads to the following conclusions. The bootstrapping results could provide us with much valuable information because the initial estimates might result from sampling noise rather than reveal the real variations. In addition, some differences do exist between the energy and CO_2 emission performance of China’s thermal power industry. Furthermore, technological progress is the main driving force for energy and CO_2 emission productivity improvement and it works better for the former.

  9. Carbon nanotubes growing on rapid thermal annealed Ni and their application to a triode-type field emission device

    International Nuclear Information System (INIS)

    Uh, Hyung Soo; Park, Sang Sik

    2006-01-01

    In this paper, we demonstrate a new triode-type field emitter arrays using carbon nanotubes (CNTs) as an electron emitter source. In the proposed structure, the gate electrode is located underneath the cathode electrode and the extractor electrode is surrounded by CNT emitters. CNTs were selectively grown on the patterned Ni catalyst layer by using plasma-enhanced chemical vapor deposition (PECVD). Vertically aligned CNTs were grown with gas mixture of acetylene and ammonia under external DC bias. Compared with a conventional under-gate structure, the proposed structure reduced the turn-on voltage by about 30%. In addition, with a view to controlling the density of CNTs, Ni catalyst thickness was varied and rapid thermal annealing (RTA) treatment was optionally adopted before CNT growth. With controlled Ni thickness and RTA condition, field emission efficiency was greatly improved by reducing the density of CNTs, which is due to the reduction of the electric field screening effect caused by dense CNTs

  10. Optical temperature sensor based on the Nd{sup 3+} infrared thermalized emissions in a fluorotellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Lalla, E.A. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); León-Luis, S.F., E-mail: sleonlui@ull.es [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Malta Consolider Team, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Monteseguro, V. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Malta Consolider Team, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Pérez-Rodríguez, C. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Cáceres, J.M. [Departamento de Ingeniería Industrial, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); and others

    2015-10-15

    The temperature dependence of the infrared luminescence of a fluorotellurite glass doped with 0.01 and 2.5 mol% of Nd{sup 3+} ions was studied in order to use it as a high temperature sensing probe. For this purpose, the emission intensities of the ({sup 4}S{sub 3/2}, {sup 4}F{sub 7/2}), ({sup 2}H{sub 9/2}, {sup 4}F{sub 5/2}),{sup 4}F{sub 3/2}→{sup 4}I{sub 9/2} transitions were measured in a wide range of temperatures from 300 upto 650 K. The changes in the emission profiles were calibrated by means of the fluorescence intensity ratio technique. The calibrations showed a strong dependence on the Nd{sup 3+} ions concentration, having the low-doped concentrated sample the best response to changes of temperature. The maximum value obtained for the thermal sensibility is 17×10{sup −4} K{sup −1} at 640 K, being one of the highest values found in the literature for Nd{sup 3+} optical temperature sensors. Finally, the experimental calibrations were compared with the theoretical temperature luminescence response calculated from the Judd–Ofelt theory. - Highlights: • Nd{sup 3+}-doped fluorotellurite glasses were prepared. • The intensities of the ({sup 4}S{sub 3/2},{sup 4}F{sub 7/2}),({sup 2}H{sub 9/2},{sup 4}F{sub 5/2}), {sup 4}F{sub 3/2}→{sup 4}I{sub 9/2} transitions. • The highest thermal sensitivity has been obtained for the glass with the lowest concentration of Nd{sup 3+} ions. • The Nd{sup 3+}-doped fluorotellurite glass fits the requirement for a good temperature sensor.

  11. Different scenarios to reduce greenhouse gas emissions of thermal power stations in Canada

    International Nuclear Information System (INIS)

    Zabihian, F.; Fung, A.S.

    2009-01-01

    The purpose of this paper is to examine greenhouse gas (GHG) emission reduction potentials in the Canadian electricity generation sector through fuel switching and the adoption of advanced power generation systems. To achieve this purpose, six different scenarios were introduced. In the first scenario existing power stations' fuel was switched to natural gas. Existing power plants were replaced by natural gas combined cycle (NGCC), integrated gasification combined cycle (IGCC), solid oxide fuel cell (SOFC), hybrid SOFC, and SOFC-IGCC hybrid power stations in scenarios number 2 to 6, respectively. (author)

  12. Recombination properties of diode structures by study of thermal emission beyond the fundamental absorption band

    International Nuclear Information System (INIS)

    Piotrowski, T; Wȩgrzecki, M; Czerwinski, A; Teslenko, G I; Malyutenko, O Y; Malyutenko, V K

    2014-01-01

    The study presents the possibilities of applying the measurement of spatial and temporal distribution of thermal radiation of a p-n junction structure located in a homogeneous temperature field higher than the ambient temperature, modulated by the presence of excess carriers injected through the junction, to determine surface recombination velocity at the injecting contact of the diode emitter and to measure the diffusion length in the base. Good agreement was obtained between the experimental results and calculations based on solutions of the transport equations.

  13. Measurement of optically and thermally stimulated electron emission from natural minerals

    DEFF Research Database (Denmark)

    Ankjærgaard, C.; Murray, A.S.; Denby, P.M.

    2006-01-01

    to a Riso TL/OSL reader, enabling optically stimulated electrons (OSE) and thermally stimulated electrons (TSE) to be measured simultaneously with optically stimulated luminescence (OSL) and thermoluminescence (TL). Repeated irradiation and measurement is possible without removing the sample from...... the counting chamber. Using this equipment both OSE and TSE from loose sand-sized grains of natural minerals has been recorded. It is shown that both the surface electron traps (giving rise to the OSE signals) and the bulk traps (giving rise to OSL) have the same dosimetric properties. A comparison of OSL...

  14. Simulated transient thermal infrared emissions of forest canopies during rainfall events

    Science.gov (United States)

    Ballard, Jerrell R.; Hawkins, William R.; Howington, Stacy E.; Kala, Raju V.

    2017-05-01

    We describe the development of a centimeter-scale resolution simulation framework for a theoretical tree canopy that includes rainfall deposition, evaporation, and thermal infrared emittance. Rainfall is simulated as discrete raindrops with specified rate. The individual droplets will either fall through the canopy and intersect the ground; adhere to a leaf; bounce or shatter on impact with a leaf resulting in smaller droplets that are propagated through the canopy. Surface physical temperatures are individually determined by surface water evaporation, spatially varying within canopy wind velocities, solar radiation, and water vapor pressure. Results are validated by theoretical canopy gap and gross rainfall interception models.

  15. Determining mineralogical variations of aeolian deposits using thermal infrared emissivity and linear deconvolution methods

    Science.gov (United States)

    Hubbard, Bernard E.; Hooper, Donald M.; Solano, Federico; Mars, John C.

    2018-01-01

    We apply linear deconvolution methods to derive mineral and glass proportions for eight field sample training sites at seven dune fields: (1) Algodones, California; (2) Big Dune, Nevada; (3) Bruneau, Idaho; (4) Great Kobuk Sand Dunes, Alaska; (5) Great Sand Dunes National Park and Preserve, Colorado; (6) Sunset Crater, Arizona; and (7) White Sands National Monument, New Mexico. These dune fields were chosen because they represent a wide range of mineral grain mixtures and allow us to gauge a better understanding of both compositional and sorting effects within terrestrial and extraterrestrial dune systems. We also use actual ASTER TIR emissivity imagery to map the spatial distribution of these minerals throughout the seven dune fields and evaluate the effects of degraded spectral resolution on the accuracy of mineral abundances retrieved. Our results show that hyperspectral data convolutions of our laboratory emissivity spectra outperformed multispectral data convolutions of the same data with respect to the mineral, glass and lithic abundances derived. Both the number and wavelength position of spectral bands greatly impacts the accuracy of linear deconvolution retrieval of feldspar proportions (e.g. K-feldspar vs. plagioclase) especially, as well as the detection of certain mafic and carbonate minerals. In particular, ASTER mapping results show that several of the dune sites display patterns such that less dense minerals typically have higher abundances near the center of the active and most evolved dunes in the field, while more dense minerals and glasses appear to be more abundant along the margins of the active dune fields.

  16. Determining mineralogical variations of aeolian deposits using thermal infrared emissivity and linear deconvolution methods

    Science.gov (United States)

    Hubbard, Bernard E.; Hooper, Donald M.; Solano, Federico; Mars, John C.

    2018-02-01

    We apply linear deconvolution methods to derive mineral and glass proportions for eight field sample training sites at seven dune fields: (1) Algodones, California; (2) Big Dune, Nevada; (3) Bruneau, Idaho; (4) Great Kobuk Sand Dunes, Alaska; (5) Great Sand Dunes National Park and Preserve, Colorado; (6) Sunset Crater, Arizona; and (7) White Sands National Monument, New Mexico. These dune fields were chosen because they represent a wide range of mineral grain mixtures and allow us to gauge a better understanding of both compositional and sorting effects within terrestrial and extraterrestrial dune systems. We also use actual ASTER TIR emissivity imagery to map the spatial distribution of these minerals throughout the seven dune fields and evaluate the effects of degraded spectral resolution on the accuracy of mineral abundances retrieved. Our results show that hyperspectral data convolutions of our laboratory emissivity spectra outperformed multispectral data convolutions of the same data with respect to the mineral, glass and lithic abundances derived. Both the number and wavelength position of spectral bands greatly impacts the accuracy of linear deconvolution retrieval of feldspar proportions (e.g. K-feldspar vs. plagioclase) especially, as well as the detection of certain mafic and carbonate minerals. In particular, ASTER mapping results show that several of the dune sites display patterns such that less dense minerals typically have higher abundances near the center of the active and most evolved dunes in the field, while more dense minerals and glasses appear to be more abundant along the margins of the active dune fields.

  17. Planck 2013 results. XI. All-sky model of thermal dust emission

    CERN Document Server

    Abergel, A; Aghanim, N; Alina, D; Alves, M I R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartlett, J G; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bonaldi, A; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bridges, M; Bucher, M; Burigana, C; Butler, R C; Cardoso, J -F; Catalano, A; Chamballu, A; Chary, R -R; Chiang, H C; Chiang, L -Y; Christensen, P R; Church, S; Clemens, M; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Falgarone, E; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Galeotta, S; Ganga, K; Ghosh, T; Giard, M; Giardino, G; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Grenier, I A; Gruppuso, A; Guillet, V; Hansen, F K; Hanson, D; Harrison, D; Helou, G; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Jaffe, A H; Jaffe, T R; Jewell, J; Joncas, G; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leonardi, R; León-Tavares, J; Lesgourgues, J; Levrier, F; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Massardi, M; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paladini, R; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rowan-Robinson, M; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savini, G; Scott, D; Seiffert, M D; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sunyaev, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Tuovinen, J; Türler, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Welikala, N; Yvon, D; Zacchei, A; Zonca, A

    2014-01-01

    This paper presents an all-sky model of dust emission from the Planck 857, 545 and 353 GHz, and IRAS 100 micron data. Using a modified black-body fit to the data we present all-sky maps of the dust optical depth, temperature, and spectral index over the 353-3000 GHz range. This model is a tight representation of the data at 5 arcmin. It shows variations of the order of 30 % compared with the widely-used model of Finkbeiner, Davis, and Schlegel. The Planck data allow us to estimate the dust temperature uniformly over the whole sky, providing an improved estimate of the dust optical depth compared to previous all-sky dust model, especially in high-contrast molecular regions. An increase of the dust opacity at 353 GHz, tau_353/N_H, from the diffuse to the denser interstellar medium (ISM) is reported. It is associated with a decrease in the observed dust temperature, T_obs, that could be due at least in part to the increased dust opacity. We also report an excess of dust emission at HI column densities lower than...

  18. Abatement of global warming gas emissions from semiconductor manufacturing processes by non-thermal plasma-catalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J-S.; Urashima, K. [McMaster Univ., McIARS and Dept. Eng. Phys., Hamilton, Ontario (Canada)

    2009-07-01

    Emission of various hazardous air pollutants (HAPs) and greenhouse gases including perfluoro-compounds (PFCs) from semiconductor industries may cause significant impact on human health and the global environment, has attracted much public attention. In this paper, an application of nonthermal plasma-adsorbent system for a removal of PFCs emission from semiconductor process flue gases is experimentally investigated. The non-thermal plasma reactor used is the ferro-electric packed-bed type barrier discharge plasma and adsorbent reactor used is Zeolite bed reactor. The results show that for a simulated semiconductor process flue gas with C{sub 2}F{sub 6} (2000ppm)/ CF{sub 4}(1000ppm)/ N{sub 2}O(1000ppm)/ N{sub 2}/ Air mixture, 54% of C{sub 2}F{sub 6} and 32% of CF{sub 4} were decomposed by the plasma reactor and 100% of C{sub 2}F{sub 6} and 98% of CF{sub 4} were removed by plasma reactor/Zeolite adsorbent hybrid system. For a simulated semiconductor process flue gas with NF{sub 3} (2000ppm)/ SiF{sub 4}(1000ppm)/ N{sub 2}O(200ppm)/ N{sub 2}/ Air mixture, 92% of NF{sub 3} and 32% of SiF{sub 4} were decomposed by the plasma reactor and total (100%) removal of the pollutant gases was achieved by plasma reactor/Zeolite adsorbent hybrid system. (author)

  19. Chemical light emission and formation of C=O radicals accompanying thermal deterioration of irradiated pure EPR

    International Nuclear Information System (INIS)

    Ito, Masayuki

    1991-01-01

    The Institute of Electrical Engineers of Japan proposed the method of successively applying radiation and heat as the environmental test method for the electric wires and cables for nuclear power stations. In this study, the method of applying radiation first and heat next was examined. In the case of trying to give by the successive application the deterioration equivalent to that by the simultaneous application of radiation and heat, it becomes an important problem whether the activation energy of thermal deterioration changes due to irradiation or not. In this study, the samples were irradiated and subsequently exposed to heat, and the chemical light emission arose at that time which reflects the oxidizing reaction was measured. Besides, the concentration of C=O radicals which were accumulated as the result of the oxidizing reaction was measured, and the temperature dependence of the constant of the concentration increase rate was examined. The experiment on chemical light emission and on the formation of C=O radicals and the results are reported. It was clarified that the concentraiton of C=O radicals formed by irradiation and heat treatment thereafter can be represented as the functions of dose and heat treatment temperature. (K.I.)

  20. Effect of thermal annealing on the emission properties of heterostructures containing a quantum-confined GaAsSb layer

    Energy Technology Data Exchange (ETDEWEB)

    Dikareva, N. V., E-mail: dnat@ro.ru; Vikhrova, O. V.; Zvonkov, B. N. [Lobachevsky State University of Nizhni Novgorod, Physico-Technical Research Institute (Russian Federation); Malekhonova, N. V. [Lobachevsky State University of Nizhni Novgorod (Russian Federation); Nekorkin, S. M. [Lobachevsky State University of Nizhni Novgorod, Physico-Technical Research Institute (Russian Federation); Pirogov, A. V.; Pavlov, D. A. [Lobachevsky State University of Nizhni Novgorod (Russian Federation)

    2015-01-15

    Heterostructures containing single GaAsSb/GaAs quantum wells and bilayer GaAsSb/InGaAs quantum wells are produced by metal-organic vapor-phase epitaxy at atmospheric pressure. The growth temperature of the quantum-confined layers is 500–570°C. The structural quality of the samples and the quality of heterointerfaces of the quantum wells are studied by the high-resolution transmission electron microscopy of cross sections. The emission properties of the heterostructures are studied by photoluminescence measurements. The structures are subjected to thermal annealing under conditions chosen in accordance with the temperature and time of growth of the upper cladding p-InGaP layer during the formation of GaAs/InGaP laser structures with an active region containing quantum-confined GaAsSb layers. It is found that such heat treatment can have a profound effect on the emission properties of the active region, only if a bilayer GaAsSb/InGaAs quantum well is formed.

  1. In situ probing of temperature in radio frequency thermal plasma using Yttrium ion emission lines during synthesis of yttria nanoparticles

    Science.gov (United States)

    Dhamale, G. D.; Tiwari, N.; Mathe, V. L.; Bhoraskar, S. V.; Ghorui, S.

    2017-07-01

    Particle feeding is used in the most important applications of radio frequency (r.f.) thermal plasmas like synthesis of nanoparticles and particle spheroidization. The study reports an in-situ investigation of radial distribution of temperature in such devices using yttrium ion emission lines under different rates of particle loading during synthesis of yttria nanoparticles. A number of interesting facts about the response of r.f. plasma to the rate of particle loading, hitherto unknown, are revealed. Observed phenomena are supported with experimental data from fast photographic experiments and actual synthesis results. The use of the Abel inversion technique together with simultaneous multi-track acquisition of emission spectra from different spatial locations using a CCD based spectrometer allowed us to extract accurate distribution of temperature inside the plasma in the presence of inherent instabilities. The temperature profiles of this type of plasma have been measured possibly for the first time while particles are being fed into the plasma. Observed changes in the temperature profiles as the particle feed rate increases are very significant. Reaction forces resulting from particle evaporation, and increased skin depth owing to the decrease in electrical conductivity in the edge region are proposed as the two different mechanisms to account for the observed changes in the temperature profile as the powder feed rate is increased. Quantitative analyses supporting the proposed mechanisms are presented.

  2. Abatement of global warming gas emissions from semiconductor manufacturing processes by non-thermal plasma-catalyst systems

    International Nuclear Information System (INIS)

    Chang, J-S.; Urashima, K.

    2009-01-01

    Emission of various hazardous air pollutants (HAPs) and greenhouse gases including perfluoro-compounds (PFCs) from semiconductor industries may cause significant impact on human health and the global environment, has attracted much public attention. In this paper, an application of nonthermal plasma-adsorbent system for a removal of PFCs emission from semiconductor process flue gases is experimentally investigated. The non-thermal plasma reactor used is the ferro-electric packed-bed type barrier discharge plasma and adsorbent reactor used is Zeolite bed reactor. The results show that for a simulated semiconductor process flue gas with C 2 F 6 (2000ppm)/ CF 4 (1000ppm)/ N 2 O(1000ppm)/ N 2 / Air mixture, 54% of C 2 F 6 and 32% of CF 4 were decomposed by the plasma reactor and 100% of C 2 F 6 and 98% of CF 4 were removed by plasma reactor/Zeolite adsorbent hybrid system. For a simulated semiconductor process flue gas with NF 3 (2000ppm)/ SiF 4 (1000ppm)/ N 2 O(200ppm)/ N 2 / Air mixture, 92% of NF 3 and 32% of SiF 4 were decomposed by the plasma reactor and total (100%) removal of the pollutant gases was achieved by plasma reactor/Zeolite adsorbent hybrid system. (author)

  3. Developing an early laekage detection system for thermal power plant boiler tubes by using acoustic emission technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Bum [RECTUSON, Co., LTD, Masan (Korea, Republic of); Roh, Seon Man [Samcheonpo Division, Korea South-East Power Co., Samcheonpo (Korea, Republic of)

    2016-06-15

    A thermal power plant has a heat exchanger tube to collect and convert the heat generated from the high temperature and pressure steam to energy, but the tubes are arranged in a complex manner. In the event that a leakage occurs in any of these tubes, the high-pressure steam leaks out and may cause the neighboring tubes to rupture. This leakage can finally stop power generation, and hence there is a dire need to establish a suitable technology capable of detecting tube leaks at an early stage even before it occurs. As shown in this paper, by applying acoustic emission (AE) technology in existing boiler tube leak detection equipment (BTLD), we developed a system that detects these leakages early enough and generates an alarm at an early stage to necessitate action; the developed system works better that the existing system used to detect fine leakages. We verified the usability of the system in a 560 MW-class thermal power plant boiler by conducting leak tests by simulating leakages from a variety of hole sizes (⌀2, ⌀5, ⌀10 mm). Results show that while the existing fine leakage detection system does not detect fine leakages of ⌀2 mm and ⌀5 mm, the newly developed system could detect leakages early enough and generate an alarm at an early stage, and it is possible to increase the signal to more than 18 dB.

  4. Study of electron temperature evolution during sawtoothing and pellet injection using thermal electron cyclotron emission in the Alcator C tokamak

    International Nuclear Information System (INIS)

    Gomez, C.C.

    1986-05-01

    A study of the electron temperature evolution has been performed using thermal electron cyclotron emission. A six channel far infrared polychromator was used to monitor the radiation eminating from six radial locations. The time resolution was <3 μs. Three events were studied, the sawtooth disruption, propagation of the sawtooth generated heatpulse and the electron temperature response to pellet injection. The sawtooth disruption in Alcator takes place in 20 to 50 μs, the energy mixing radius is approx. 8 cm or a/2. It is shown that this is inconsistent with single resonant surface Kadomtsev reconnection. Various forms of scalings for the sawtooth period and amplitude were compared. The electron heatpulse propagation has been used to estimate chi e(the electron thermal diffusivity). The fast temperature relaxation observed during pellet injection has also been studied. Electron temperature profile reconstructions have shown that the profile shape can recover to its pre-injection form in a time scale of 200 μs to 3 ms depending on pellet size

  5. Developing an early laekage detection system for thermal power plant boiler tubes by using acoustic emission technology

    International Nuclear Information System (INIS)

    Lee, Sang Bum; Roh, Seon Man

    2016-01-01

    A thermal power plant has a heat exchanger tube to collect and convert the heat generated from the high temperature and pressure steam to energy, but the tubes are arranged in a complex manner. In the event that a leakage occurs in any of these tubes, the high-pressure steam leaks out and may cause the neighboring tubes to rupture. This leakage can finally stop power generation, and hence there is a dire need to establish a suitable technology capable of detecting tube leaks at an early stage even before it occurs. As shown in this paper, by applying acoustic emission (AE) technology in existing boiler tube leak detection equipment (BTLD), we developed a system that detects these leakages early enough and generates an alarm at an early stage to necessitate action; the developed system works better that the existing system used to detect fine leakages. We verified the usability of the system in a 560 MW-class thermal power plant boiler by conducting leak tests by simulating leakages from a variety of hole sizes (⌀2, ⌀5, ⌀10 mm). Results show that while the existing fine leakage detection system does not detect fine leakages of ⌀2 mm and ⌀5 mm, the newly developed system could detect leakages early enough and generate an alarm at an early stage, and it is possible to increase the signal to more than 18 dB

  6. Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases.

    Science.gov (United States)

    Zickfeld, Kirsten; Solomon, Susan; Gilford, Daniel M

    2017-01-24

    Mitigation of anthropogenic greenhouse gases with short lifetimes (order of a year to decades) can contribute to limiting warming, but less attention has been paid to their impacts on longer-term sea-level rise. We show that short-lived greenhouse gases contribute to sea-level rise through thermal expansion (TSLR) over much longer time scales than their atmospheric lifetimes. For example, at least half of the TSLR due to increases in methane is expected to remain present for more than 200 y, even if anthropogenic emissions cease altogether, despite the 10-y atmospheric lifetime of this gas. Chlorofluorocarbons and hydrochlorofluorocarbons have already been phased out under the Montreal Protocol due to concerns about ozone depletion and provide an illustration of how emission reductions avoid multiple centuries of future TSLR. We examine the "world avoided" by the Montreal Protocol by showing that if these gases had instead been eliminated in 2050, additional TSLR of up to about 14 cm would be expected in the 21st century, with continuing contributions lasting more than 500 y. Emissions of the hydrofluorocarbon substitutes in the next half-century would also contribute to centuries of future TSLR. Consideration of the time scales of reversibility of TSLR due to short-lived substances provides insights into physical processes: sea-level rise is often assumed to follow air temperature, but this assumption holds only for TSLR when temperatures are increasing. We present a more complete formulation that is accurate even when atmospheric temperatures are stable or decreasing due to reductions in short-lived gases or net radiative forcing.

  7. Detection of non-thermal X-ray emission in the lobes and jets of Cygnus A

    Science.gov (United States)

    de Vries, M. N.; Wise, M. W.; Huppenkothen, D.; Nulsen, P. E. J.; Snios, B.; Hardcastle, M. J.; Birkinshaw, M.; Worrall, D. M.; Duffy, R. T.; McNamara, B. R.

    2018-06-01

    We present a spectral analysis of the lobes and X-ray jets of Cygnus A, using more than 2 Ms of Chandra observations. The X-ray jets are misaligned with the radio jets and significantly wider. We detect non-thermal emission components in both lobes and jets. For the eastern lobe and jet, we find 1 keV flux densities of 71_{-10}^{+10} nJy and 24_{-4}^{+4} nJy, and photon indices of 1.72_{-0.03}^{+0.03} and 1.64_{-0.04}^{+0.04} respectively. For the western lobe and jet, we find flux densities of 50_{-13}^{+12} nJy and 13_{-5}^{+5} nJy, and photon indices of 1.97_{-0.10}^{+0.23} and 1.86_{-0.12}^{+0.18} respectively. Using these results, we modeled the electron energy distributions of the lobes as broken power laws with age breaks. We find that a significant population of non-radiating particles is required to account for the total pressure of the eastern lobe. In the western lobe, no such population is required and the low energy cutoff to the electron distribution there needs to be raised to obtain pressures consistent with observations. This discrepancy is a consequence of the differing X-ray photon indices, which may indicate that the turnover in the inverse-Compton spectrum of the western lobe is at lower energies than in the eastern lobe. We modeled the emission from both jets as inverse-Compton emission. There is a narrow region of parameter space for which the X-ray jet can be a relic of an earlier active phase, although lack of knowledge about the jet's electron distribution and particle content makes the modelling uncertain.

  8. Thermal behavior of H-aggregate in a mixed Langmuir-Blodgett film of merocyanine dye, arachidic acid, and n-octadecane ternary system investigated by UV-visible and IR absorption spectroscopy.

    Science.gov (United States)

    Hirano, Yoshiaki; Tateno, Shinsuke; Yamashita, Yoshihide; Ozaki, Yukihiro

    2008-11-13

    We have investigated the thermal behavior of H-aggregate in a mixed Langmuir-Blodgett (LB) film of the merocyanine dye (MS18)-arachidic acid (C20)- n-octadecane (AL18) ternary system by means of UV-visible and IR absorption spectroscopy in the range from 25 to 250 degrees C with a continuous scan. The results of both UV-visible and IR spectra indicate that the temperature-dependent variation in MS 18 aggregation state is linked not only with the degree of intramolecular charge transfer and the behavior of packing, orientation, conformation, and thermal mobility of the MS18 hydrocarbon chain but also with the presence and absence of AL18. The H-aggregate dissociates from 25 up to 50 degrees C, which is caused by the AL18 evaporation from the mixed LB film and the increment of thermal mobility of the MS18 hydrocarbon chain. From 110 to 160 degrees C, blue-shifted bands, attributed to the oligomeric MS18 aggregation, appear near 515 nm in the MS18-C 20-AL18 ternary system as well. The temperature at which the 515 nm band occurs is identical for both present ternary system and previously investigated MS18-deuterated arachidic acid (C20- d) binary system, and it is in good agreement with the melting point (110 degrees C) of cadmium arachidate (CdC20). Therefore, it is indicated that the driving force which induces the 515 nm band comes from the melting phenomenon of CdC20 molecules which are phase-separated from MS 18 molecules in as-deposited LB films.

  9. Pulsed Thermal Emission from the Accreting Pulsar XMMU J054134.7-682550

    Science.gov (United States)

    Manousakis, Antonis; Walter, Roland; Audard, Marc; Lanz, Thierry

    2009-05-01

    XMMU J054134.7-682550, located in the LMC, featured a type II outburst in August 2007. We analyzed XMM-Newton (EPIC-MOS) and RXTE (PCA) data in order to derive the spectral and temporal characteristics of the system throughout the outburst. Spectral variability, spin period evolution, energy dependent pulse shape are discussed. The outburst (LX~3×1038 erg/s~LEDD) spectrum can be modeled using, cutoff power law, soft X-ray blackbody, disk emission, and cyclotron absorption line. The blackbody component shows a sinusoidal behavior, expected from hard X-ray reprocessing on the inner edge of the accretion disk. The thickness of the inner accretion disk (width of ~75 km) can be constrained. The spin-up of the pulsar during the outburst is the signature of a (huge) accretion rate. Simbol-X will provide similar capabilities as XMM-Newton and RXTE together, for such bright events.

  10. Calculation of the net emission coefficient of an air thermal plasma at very high pressure

    International Nuclear Information System (INIS)

    Billoux, T; Cressault, Y; Teulet, Ph; Gleizes, A

    2012-01-01

    The aim of this paper is to present an accurate evaluation of the phenomena appearing for high pressure air plasmas supposed to be in local thermodynamic equilibrium (LTE). In the past, we already calculated the net emission coefficient for air mixtures at atmospheric pressure and for temperatures up to 30kK (molecular contribution being restricted to 10kK). Unfortunately, the existence of high pressures does not allow us to use this database due to the non-ideality of the plasma (Viriel and Debye corrections, energy cut-off ...), and due to the significant shifts of molecular reactions towards upper temperatures. Consequently, this paper proposes an improvement of our previous works with a consideration of high pressure corrections in the composition algorithm in order to take into account the pressure effects, and with a new calculation of all the contributions of the plasma radiation (atomic lines and continuum, molecular continuum, and molecular bands) using an updated database. A particular attention is paid to calculate the contribution of all the major molecular band systems to the radiation: O 2 (Schumann–Runge), N 2 (VUV, 1st and 2nd positive), NO (IR, β, γ, δ, element of ) and N 2 + (1st negative and Meinel). The discrete atomic lines and molecular bands radiation including the overlapping are calculated by a line-by-line method up to 30kK and 100 bar. This updated database is validated in the case of optically thin plasmas and pressure of 1bar by the comparison of our integrated emission strength with the published results. Finally, this work shows the necessity to extend the molecular radiation database up to 15kK at high pressure (bands and continuum) since their corresponding contributions could not be neglected at high temperature.

  11. First hard X-ray detection of the non-thermal emission around the Arches cluster: morphology and spectral studies with NuSTAR

    DEFF Research Database (Denmark)

    Krivonos, Roman A.; Tomsick, John A.; Bauer, Franz E.

    2014-01-01

    The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Ku line emission at 6.4 keV from material that is n......The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Ku line emission at 6.4 keV from material...... and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity...... of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agreement with the low-energy cosmic-ray proton excitation scenario....

  12. THERMAL EMISSION AND TIDAL HEATING OF THE HEAVY AND ECCENTRIC PLANET XO-3b

    International Nuclear Information System (INIS)

    Machalek, Pavel; Greene, Tom; McCullough, Peter R.; Burrows, Adam; Burke, Christopher J.; Hora, Joseph L.; Johns-Krull, Christopher M.; Deming, Drake L.

    2010-01-01

    We determined the flux ratios of the heavy and eccentric planet XO-3b to its parent star in the four Infrared Array Camera bands of the Spitzer Space Telescope: 0.101% ± 0.004% at 3.6 μm; 0.143% ± 0.006% at 4.5 μm; 0.134% ± 0.049% at 5.8 μm; and 0.150% ± 0.036% at 8.0 μm. The flux ratios are within [-2.2, 0.3, -0.8, and -1.7]σ of the model of XO-3b with a thermally inverted stratosphere in the 3.6 μm, 4.5 μm, 5.8 μm, and 8.0 μm channels, respectively. XO-3b has a high illumination from its parent star (F p ∼ (1.9-4.2) x 10 9 erg cm -2 s -1 ) and is thus expected to have a thermal inversion, which we indeed observe. When combined with existing data for other planets, the correlation between the presence of an atmospheric temperature inversion and the substellar flux is insufficient to explain why some high insolation planets like TrES-3 do not have stratospheric inversions and some low insolation planets like XO-1b do have inversions. Secondary factors such as sulfur chemistry, atmospheric metallicity, amounts of macroscopic mixing in the stratosphere, or even dynamical weather effects likely play a role. Using the secondary eclipse timing centroids, we determined the orbital eccentricity of XO-3b as e = 0.277 ± 0.009. The model radius-age trajectories for XO-3b imply that at least some amount of tidal heating is required to inflate the radius of XO-3b, and the tidal heating parameter of the planet is constrained to Q p ∼ 6 .

  13. Generation and Use of Thermal Energy in the Industrial Sector and Opportunities to Reduce its Carbon Emissions

    International Nuclear Information System (INIS)

    McMillan, Colin; Boardman, Richard; McKellar, Michael; Sabharwall, Piyush; Ruth, Mark; Bragg-Sitton, Shannon

    2016-01-01

    Changes are occurring throughout the U.S. economy, especially in regard to how energy is generated and used in the electricity, buildings, industrial, and transportation sectors. These changes are being driven by environmental and energy security concerns and by economics. The electric-sector market share of natural gas and variable renewable generation, such as wind and solar photovoltaics (PV), continues to grow. The buildings sector is evolving to meet efficiency standards, the transportation sector is evolving to meet efficiency and renewable fuels standards, and the industrial sector is evolving to reduce emissions. Those changes are driving investment and utilization strategies for generation and other assets. Nuclear and renewable energy sources are important to consider in the energy sector’s evolution because both are considered to be clean and non-carbon-emitting energy sources. The Idaho National Laboratory (INL) and the National Renewable Energy Laboratory (NREL) are jointly investigating potential synergies between technologies exploiting nuclear and renewable energy sources. The two laboratories have held several joint workshops since 2011. Those workshops brought together experts in both areas to identify synergies and potential opportunities to work together. Workshop participants identified nuclear-renewable hybrid energy systems (N-R HESs) as one of the opportunities and recommended investigating whether N-R HESs could both generate dispatchable electricity without carbon emissions and provide clean energy to industrial processes. They also recommended analyzing the potential for N-R HESs to provide dispatchable capacity to a grid with high penetrations of non-dispatchable resources and to investigate whether real inertia provided by thermal power cycles within N-R HESs provides value to the grid. This report is one of a series of reports INL and NREL are producing to investigate the technical and economic aspects of N-R HESs. Previous reports

  14. Generation and Use of Thermal Energy in the Industrial Sector and Opportunities to Reduce its Carbon Emissions

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, Colin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Boardman, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); McKellar, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bragg-Sitton, Shannon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Changes are occurring throughout the U.S. economy, especially in regard to how energy is generated and used in the electricity, buildings, industrial, and transportation sectors. These changes are being driven by environmental and energy security concerns and by economics. The electric-sector market share of natural gas and variable renewable generation, such as wind and solar photovoltaics (PV), continues to grow. The buildings sector is evolving to meet efficiency standards, the transportation sector is evolving to meet efficiency and renewable fuels standards, and the industrial sector is evolving to reduce emissions. Those changes are driving investment and utilization strategies for generation and other assets. Nuclear and renewable energy sources are important to consider in the energy sector’s evolution because both are considered to be clean and non-carbon-emitting energy sources. The Idaho National Laboratory (INL) and the National Renewable Energy Laboratory (NREL) are jointly investigating potential synergies between technologies exploiting nuclear and renewable energy sources. The two laboratories have held several joint workshops since 2011. Those workshops brought together experts in both areas to identify synergies and potential opportunities to work together. Workshop participants identified nuclear-renewable hybrid energy systems (N-R HESs) as one of the opportunities and recommended investigating whether N-R HESs could both generate dispatchable electricity without carbon emissions and provide clean energy to industrial processes. They also recommended analyzing the potential for N-R HESs to provide dispatchable capacity to a grid with high penetrations of non-dispatchable resources and to investigate whether real inertia provided by thermal power cycles within N-R HESs provides value to the grid. This report is one of a series of reports INL and NREL are producing to investigate the technical and economic aspects of N-R HESs. Previous reports

  15. Efficient conversion from UV light to near-IR emission in Yb{sup 3+}-doped triple-layered perovskite CaLaNb{sub 3}O{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuting; Li, Yuze; Qin, Lin; Huang, Yanlin [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Chuanxiang, E-mail: qinchuanxiang@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Tsuboi, Taiju [Jiangsu-Singapore Joint Research Center for Organic/Bio-Electronics & Information Displays and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing 211816 (China); Huang, Wei, E-mail: wei-huang@njtech.edu.cn [Jiangsu-Singapore Joint Research Center for Organic/Bio-Electronics & Information Displays and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing 211816 (China)

    2015-04-15

    Graphical abstract: CaRNb{sub 3}O{sub 10} is a self-activated oxide due to charge transfer transition in octahedral NbO{sub 6} groups. CaLaNb{sub 3}O{sub 10}:Yb{sup 3+} presents intense IR emission due to the cooperative energy transfer from host (NbO{sub 6}) to Yb{sup 3+} is responsible. It could be expected to be potentially applicable for enhancing photovoltaic conversion efficiency of Si-based solar cells. - Abstract: Yb{sup 3+}-doped triple-layered perovskite CaLaNb{sub 3}O{sub 10} micro-particles were synthesized via the solid-state reaction method. The crystal structure and morphology of the polycrystalline samples were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurements, respectively. The reflectance spectra, photoluminescence (PL) excitation and emission spectra, the decay curves, and the absolute quantum efficiency (QE) of the near-infrared (NIR) emission (910–1100 nm) were measured. Under excitation of UV light, Yb{sup 3+}-doped perovskite shows an intense NIR emission attributed to the {sup 2}F{sub 5/2} → {sup 2}F{sub 7/2} transitions of Yb{sup 3+} ions, which could match maximum spectral response of a Si-based solar cell. This is beneficial for its possible application in an enhancement of the photovoltaic conversion efficiency of solar energy utilization. The efficient energy transfer in Yb{sup 3+}-doped CaLaNb{sub 3}O{sub 10} from NbO{sub 6} groups into Yb{sup 3+} ions was confirmed by the spectra and fluorescent decay measurements. Cooperative energy transfer (CET) was supposed to be the NIR emission mechanism.

  16. Assessment of a landfill methane emission screening method using an unmanned aerial vehicle mounted thermal infrared camera – A field study

    DEFF Research Database (Denmark)

    Fjelsted, Lotte; Christensen, A. G.; Larsen, J. E.

    2018-01-01

    An unmanned aerial vehicle (UAV)-mounted thermal infrared (TIR) camera’s ability to delineate landfill gas (LFG) emission hotspots was evaluated in a field test at two Danish landfills (Hedeland landfill and Audebo landfill). At both sites, a test area of 100 m2 was established and divided into a...

  17. Sensing Properties of a Novel Temperature Sensor Based on Field Assisted Thermal Emission

    Directory of Open Access Journals (Sweden)

    Zhigang Pan

    2017-02-01

    Full Text Available The existing temperature sensors using carbon nanotubes (CNTs are limited by low sensitivity, complicated processes, or dependence on microscopy to observe the experimental results. Here we report the fabrication and successful testing of an ionization temperature sensor featuring non-self-sustaining discharge. The sharp tips of nanotubes generate high electric fields at relatively low voltages, lowering the work function of electrons emitted by CNTs, and thereby enabling the safe operation of such sensors. Due to the temperature effect on the electron emission of CNTs, the collecting current exhibited an exponential increase with temperature rising from 20 °C to 100 °C. Additionally, a higher temperature coefficient of 0.04 K−1 was obtained at 24 V voltage applied on the extracting electrode, higher than the values of other reported CNT-based temperature sensors. The triple-electrode ionization temperature sensor is easy to fabricate and converts the temperature change directly into an electrical signal. It shows a high temperature coefficient and good application potential.

  18. Experimental study of radioactive aerosols emission during the thermal degradation of organic materials in nuclear facilities

    International Nuclear Information System (INIS)

    Fernandez, Yvette

    1993-01-01

    Radioactive products may be released during a fire in nuclear fuel cycles facilities. These products must be confined to avoid a contamination spread in the environment. It is therefore necessary to be able to predict the amount and the physico-chemical forms of radioactive material that may be airborne. The aim of this study is to determine experimentally the release of contamination aerosols in a typical fire scenario involving plutonium oxide in a glove box. Firstly, this phenomenon has been studied in a small scale test chamber where samples of polymethylmethacrylate (Plexiglas) contaminated by cerium oxide (used as a substitute for plutonium oxide) were submitted to thermal degradation (pyrolysis and combustion). The release of radioactive material is determined by the quantity of contaminant emitted, the kinetics of the release and the particle size distribution of aerosols. Secondly, the development of an experimental procedure allowed to realize large scale fires in more realistic conditions. The experimental tools developed in the course of this study allow to consider application to other scenarios. (author) [fr

  19. Study of Thermal-Field Emission Properties and Investigation of Temperature dependent Noise in the Emission Current form vertical Carbon nanotube emitters

    KAUST Repository

    Kolekar, Sadhu; Patole, Shashikant P.; Patil, Sumati; Yoo, J.B.; Dharmadhikari, C.V.

    2017-01-01

    We have investigated temperature dependent field electron emission characteristics of vertical carbon nanotubes (CNTs). The generalized expression for electron emission from well defined cathode surface is given by Millikan and Lauritsen [1

  20. Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 1; Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

    Science.gov (United States)

    Raj, S. V.

    2017-01-01

    This two-part paper reports the thermophysical properties of several cold and vacuum plasma sprayed monolithic Cu and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys, stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold sprayed or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities and total hemispherical emissivities of these cold and vacuum sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

  1. Study of Thermal-Field Emission Properties and Investigation of Temperature dependent Noise in the Emission Current form vertical Carbon nanotube emitters

    KAUST Repository

    Kolekar, Sadhu

    2017-05-05

    We have investigated temperature dependent field electron emission characteristics of vertical carbon nanotubes (CNTs). The generalized expression for electron emission from well defined cathode surface is given by Millikan and Lauritsen [1] for the combination of temperature and electric field effect. The same expression has been used to explain the electron emission characteristics from vertical CNT emitters. Furthermore, this has been applied to explain the electron emission for different temperatures ranging from room temperature to 1500 K. The real-time field electron emission images at room temperature and 1500 K are recorded by using Charge Coupled Device (CCD), in order to understand the effect of temperature on electron emission spots in image morphology (as indicated by ring like structures) and electron emission spot intensity of the emitters. Moreover, the field electron emission images can be used to calculate the total number of emitters per cm2 for electron emission. The calculated number of emitters per cm2 is 4.5x107 and, the actual number emitters per cm2 present for electron emission calculated from Atomic Force Microscopy (AFM) data is 1.2x1012. The measured Current-Voltage (I-V) characteristics obey the Folwer-Nordheim (F-N) type behavior. The fluctuations in the emission current are recorded at different temperatures and, temperature dependence of power spectral density obeys power law relation s(f)=I2/f2 with that of emission current and frequency.

  2. Photocatalytic decomposition of selected estrogens and their estrogenic activity by UV-LED irradiated TiO{sub 2} immobilized on porous titanium sheets via thermal-chemical oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Arlos, Maricor J., E-mail: mjarlos@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Liang, Robert; Hatat-Fraile, Melisa M. [Centre for Advanced Materials Joining, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Bragg, Leslie M. [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Zhou, Norman Y. [Centre for Advanced Materials Joining, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Servos, Mark R. [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Andrews, Susan A. [Civil Engineering Department, University of Toronto, Toronto, Ontario M5S 1A4 (Canada)

    2016-11-15

    Highlights: • TiO{sub 2} self-assembled on oxidized porous titanium sheets. • UV-LED/TiO{sub 2} membrane treatment reduced the concentrations of estrogens. • Different pH conditions affect treatment efficiency. • The estrogenic activity removal was similar to the chemical disappearance. - Abstract: The removal of endocrine disrupting compounds (EDCs) remains a big challenge in water treatment. Risks associated with these compounds are not clearly defined and it is important that the water industry has additional options to increase the resiliency of water treatment systems. Titanium dioxide (TiO{sub 2}) has potential applications for the removal of EDCs from water. TiO{sub 2} has been immobilized on supports using a variety of synthesis methods to increase its feasibility for water treatment. In this study, we immobilized TiO{sub 2} through the thermal-chemical oxidation of porous titania sheets. The efficiency of the material to degrade target EDCs under UV-LED irradiation was examined under a wide range of pH conditions. A yeast-estrogen screen assay was used to complement chemical analysis in assessing removal efficiency. All compounds but 17β-estradiol were degraded and followed a pseudo first-order kinetics at all pH conditions tested, with pH 4 and pH 11 showing the most and the least efficient treatments respectively. In addition, the total estrogenic activity was substantially reduced even with the inefficient degradation of 17β-estradiol. Additional studies will be required to optimize different treatment conditions, UV-LED configurations, and membrane fouling mitigation measures to make this technology a more viable option for water treatment.

  3. A modified gravitational search algorithm based on a non-dominated sorting genetic approach for hydro-thermal-wind economic emission dispatching

    International Nuclear Information System (INIS)

    Chen, Fang; Zhou, Jianzhong; Wang, Chao; Li, Chunlong; Lu, Peng

    2017-01-01

    Wind power is a type of clean and renewable energy, and reasonable utilization of wind power is beneficial to environmental protection and economic development. Therefore, a short-term hydro-thermal-wind economic emission dispatching (SHTW-EED) problem is presented in this paper. The proposed problem aims to distribute the load among hydro, thermal and wind power units to simultaneously minimize economic cost and pollutant emission. To solve the SHTW-EED problem with complex constraints, a modified gravitational search algorithm based on the non-dominated sorting genetic algorithm-III (MGSA-NSGA-III) is proposed. In the proposed MGSA-NSGA-III, a non-dominated sorting approach, reference-point based selection mechanism and chaotic mutation strategy are applied to improve the evolutionary process of the original gravitational search algorithm (GSA) and maintain the distribution diversity of Pareto optimal solutions. Moreover, a parallel computing strategy is introduced to improve the computational efficiency. Finally, the proposed MGSA-NSGA-III is applied to a typical hydro-thermal-wind system to verify its feasibility and effectiveness. The simulation results indicate that the proposed algorithm can obtain low economic cost and small pollutant emission when dealing with the SHTW-EED problem. - Highlights: • A hybrid algorithm is proposed to handle hydro-thermal-wind power dispatching. • Several improvement strategies are applied to the algorithm. • A parallel computing strategy is applied to improve computational efficiency. • Two cases are analyzed to verify the efficiency of the optimize mode.

  4. HerMES: The rest-frame UV emission and a lensing model for the z = 6.34 luminous dusty starburst galaxy HFLS3

    International Nuclear Information System (INIS)

    Cooray, Asantha; Calanog, Jae; Casey, C. M.; Ma, Brian; Osage, W. A.; Wardlow, Julie L.; Bock, J.; Bridge, C.; Burgarella, D.; Bussmann, R. S.; Clements, D.; Conley, A.; Farrah, D.; Fu, H.; Gavazzi, R.; Ivison, R. J.; La Porte, N.; Lo Faro, B.; Magdis, G.; Oliver, S. J.

    2014-01-01

    We discuss the rest-frame ultraviolet emission from the starbursting galaxy HFLS3 at a redshift of 6.34. The galaxy was discovered in Herschel/SPIRE data due to its red color in the submillimeter wavelengths from 250 to 500 μm. Keck/NIRC2 K s -band adaptive optics imaging data showed two potential near-IR counterparts near HFLS3. Previously, the northern galaxy was taken to be in the foreground at z = 2.1, while the southern galaxy was assumed to be HFLS3's near-IR counterpart. The recently acquired Hubble/WFC3 and Advanced Camera for Surveys (ACS) imaging data show conclusively that both optically bright galaxies are in the foreground at z < 6. A new lensing model based on the Hubble imaging data and the millimeter-wave continuum emission yields a magnification factor of 2.2 ± 0.3, with a 95% confidence upper limit on the magnification of 3.5. When corrected for lensing, the instantaneous star formation rate is 1320 M ☉ yr –1 , with the 95% confidence lower limit around 830 M ☉ yr –1 . The dust and stellar masses of HFLS3 from the same spectral energy distribution (SED) models are at the level of 3 × 10 8 M ☉ and ∼5 × 10 10 M ☉ , respectively, with large systematic uncertainties on assumptions related to the SED model. With Hubble/WFC3 images, we also find diffuse near-IR emission about 0.5 arcsec (∼3 kpc) to the southwest of HFLS3 that remains undetected in the ACS imaging data. The emission has a photometric redshift consistent with either z ∼ 6 or a dusty galaxy template at z ∼ 2.

  5. Re-emission and thermal desorption of deuterium from plasma sprayed tungsten coatings for application in ASDEX-upgrade

    International Nuclear Information System (INIS)

    Garcia-Rosales, C.; Franzen, P.; Plank, H.; Roth, J.; Gauthier, E.

    1996-01-01

    The trapping and release of deuterium implanted with an energy of 100 eV in wrought and in plasma sprayed tungsten of different manufacture and structure has been investigated by means of re-emission as well as thermal and isothermal desorption spectroscopy. The experimental data for wrought tungsten are compared with model calculations with the PIDAT code in order to estimate the parameters governing diffusion, surface recombination and trapping in tungsten. The amount of retained deuterium in tungsten is of the same order of magnitude as in graphite for the implantation parameters used in this work. The mobile hydrogen concentration in tungsten during the implantation is of the same order of magnitude than the trapped one, being released after the termination of the implantation. The fraction of deuterium trapped to defects increases strongly with the porosity of the samples. The temperature needed for the release of the trapped deuterium (∝600 K) are considerably lower than for graphite, due to the smaller trapping energy (≤1.5 eV). (orig.)

  6. Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue-Caviahue Volcanic Complex (Argentina)

    Science.gov (United States)

    Chiodini, Giovanni; Cardellini, Carlo; Lamberti, María Clara; Agusto, Mariano; Caselli, Alberto; Liccioli, Caterina; Tamburello, Giancarlo; Tassi, Franco; Vaselli, Orlando; Caliro, Stefano

    2015-10-01

    The north-western sector of Caviahue caldera (Argentina), close to the active volcanic system of Copahue, is characterized by the presence of several hydrothermal sites that host numerous fumarolic emissions, anomalous soil diffuse degassing of CO2 and hot soils. In March 2014, measurements of soil CO2 fluxes in 5 of these sites (namely, Las Máquinas, Las Maquinitas I, Las Maquinitas II, Anfiteatro, and Termas de Copahue) allowed an estimation that 165 t of deeply derived CO2 is daily released. The gas source is likely related to a relatively shallow geothermal reservoir containing a single vapor phase as also suggested by both the geochemical data from the 3 deep wells drilled in the 1980s and gas geoindicators applied to the fumarolic discharges. Gas equilibria within the H-C-O gas system indicate the presence of a large, probably unique, single phase vapor zone at 200-210 °C feeding the hydrothermal manifestations of Las Máquinas, Las Maquinitas I and II and Termas de Copahue. A natural thermal release of 107 MW was computed by using CO2 as a tracer of the original vapor phase. The magmatic signature of the incondensable fumarolic gases, the wide expanse of the hydrothermal areas and the remarkable high amount of gas and heat released by fluid expulsion seem to be compatible with an active magmatic intrusion beneath this portion of the Caviahue caldera.

  7. Use of emission spectroscopy as a tool for optimization of plasma hearth operation for hazardous waste thermal treatment

    International Nuclear Information System (INIS)

    Monts, D.L.; Bauman, L.E.; Lengel, R.K.; Wang, W.; Lin, J.; Cook, R.L.; Shepard, W.S.

    1994-01-01

    Thermal processing of mixed wastes by plasma hearth vitrification requires optimization of and continuous monitoring of plasma hearth operation. A series of investigations utilizing emission spectroscopy has been initiated to characterize the plasma of a 96 kW plasma hearth in order to determine optimum conditions for monitoring and hence controlling plasma hearth performance. The plasma hearth test stand is based upon a 96 kW, transferred arc plasma torch. The torch is mounted in a vacuum vessel through an electrically operated XYZ Gimbal mount. The peak operating power depends on the gas used for the plasma. The operational limits for DC voltage are 180 V to 550 V; and the current is operated at a constant value, selectable in the range from 72 to 200 amps. The plasma arc length can be varied from 2.5 cm to 25 cm, and is dependent on the supply voltage and the process gas used. The arc current and voltage, gas pressure, cooling water flow, and cooling water temperature are monitored and stored by a PC-based data acquisition system. Five optical ports are available for making optical diagnostic measurements

  8. Highly thermal conductivity and infrared emissivity of flexible transparent film heaters utilizing silver-decorated carbon nanomaterials as fillers

    International Nuclear Information System (INIS)

    Li, Yu-An; Chen, Yin-Ju; Tai, Nyan-Hwa

    2014-01-01

    A flexible transparent film heater using functionalized few-walled carbon nanotubes and graphene nanosheets decorated with silver nanoparticles as fillers and poly(3,4-ethylenedioxythiophene)- poly(4-stryrenesulfonate) (PEDOT:PSS) as a dispersant possesses excellent optoelectronic and electrothermal properties. The film possesses a low sheet resistance of 53.0 ± 4.2 ohm · sq −1 , a transmittance of 80.2 ± 0.8% at a wavelength of 550 nm, a high thermal conductivity of 142.0 ± 9.6 W · m −1  · K −1 , a quick response time of less than 60 s, stable heating performance, good reliability, low power consumption, flexibility, and uniform heat diffusion. Besides, the film shows an average infrared emissivity of 0.53 in the wavelength range of 4 to 14 μm, which shows an outstanding heat release performance by radiation. The flexible transparent film heaters adopting graphene and carbon nanotubes as fillers boast excellent electrothermal performance through heat conduction and infrared radiation, suggesting that they are good substitutes for traditional metallic and indium tin oxide film heaters. (papers)

  9. Absolute UV and VUV emission in the 110-400 nm region from 13.56 MHz driven hollow slot microplasmas operating in open air

    International Nuclear Information System (INIS)

    Rahman, A; Yalin, A P; Surla, V; Stan, O; Hoshimiya, K; Yu, Z; Littlefield, Eric; Collins, G J

    2004-01-01

    We present absolute optical emission spectra in the 110-400 nm regions from radio-frequency-driven (13.56 MHz) hollow slot microplasmas operating in open air at atmospheric pressure. The term microplasma in our research refers to inter-electrode separation (100-600 μm) only, as electrode lengths are scalable from 1 to 30 cm. This creates an extended slot plasma and an associated afterglow plume as described herein. Spectra are presented for gas flows through the microelectrodes of argon and helium with small admixtures of hydrogen and nitrogen into open air. The spectra are discussed in terms of species origin and magnitude of the dominant emission lines. Atomic O and N lines dominate the 110-200 nm region, whereas, in the 200-400 nm region, NO, N 2 , N 2 + and NH molecular lines are strongest. The role of the N 2 A 3 Σ u state in the open air microplasmas is discussed and the second positive system of molecular nitrogen (N 2 (C 3 Π g -B 3 Π g )), is used to measure the rotational (gas) temperature. Finally, we compare the efficiency and magnitude of light emission from the open air microplasmas with values attainable from commercial sealed mercury lamps in the UVB and UVC regions

  10. NOx emissions and thermal efficiencies of small scale biomass-fuelled combustion plant with reference to process industries in a developing country

    International Nuclear Information System (INIS)

    Tariq, A.S.; Purvis, M.R.I.

    1996-01-01

    Solid biomass materials are an important industrial fuel in many developing countries and also show good potential for usage in Europe within a future mix of renewable energy resources. The sustainable use of wood fuels for combustion relies on operation of plant with acceptable thermal efficiency. There is a clear link between plant efficiency and environmental impacts due to air pollution and deforestation. To supplement a somewhat sparse literature on thermal efficiencies and nitrogen oxide emissions from biomass-fuelled plants in developing countries, this paper presents results for tests carried out on 14 combustion units obtained during field trials in Sri Lanka. The plants tested comprised steam boilers and process air heaters. Biomass fuels included: rubber-wood, fuelwood from natural forests; coconut shells; rice husks; and sugar can bagasse. Average NO x (NO and NO 2 ) emissions for the plants were found to be 47 gNO 2 GJ -1 with 18% conversion of fuel nitrogen. The former value is the range of NO x emission values quoted for combustion of coal in grate-fired systems; some oil-fired systems and systems operating on natural gas, but is less than the emission levels for the combustion of pulverized fuel and heavy fuel oil. This value is significantly within current European standards for NO x emission from large combustion plants. Average thermal efficiency of the plants was found to be 50%. Observations made on operational practices demonstrated that there is considerable scope for the improvement of this thermal efficiency value by plant supervisor training, drying of fuelwood and the use of simple instruments for monitoring plant performance. (Author)

  11. Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 1: Slant-columns and their ratios

    Directory of Open Access Journals (Sweden)

    M. Grutter

    2012-02-01

    Full Text Available The composition and emission rates of volcanic gas plumes provide insight of the geologic internal activity, atmospheric chemistry, aerosol formation and radiative processes around it. Observations are necessary for public security and the aviation industry. Ground-based thermal emission infrared spectroscopy, which uses the radiation of the volcanic gas itself, allows for continuously monitoring during day and night from a safe distance. We present measurements on Popocatépetl volcano based on thermal emission spectroscopy during different campaigns between 2006–2009 using a Scanning Infrared Gas Imaging System (SIGIS. The experimental set-up, measurement geometries and analytical algorithms are described. The equipment was operated from a safe distance of 12 km from the volcano at two different spectral resolutions: 0.5 and 4 cm−1. The 2-dimensional scanning capability of the instrument allows for an on-line visualization of the volcanic SO2 plume and its animation. SiF4 was also identified in the infrared spectra recorded at both resolutions. The SiF4/SO2 molecular ratio can be calculated from each image and used as a highly useful parameter to follow changes in volcanic activity. A small Vulcanian eruption was monitored during the night of 16 to 17 November 2008 and strong ash emission together with a pronounced SO2 cloud was registered around 01:00 a.m. LST (Local Standard Time. Enhanced SiF4/SO2 ratios were observed before and after the eruption. A validation of the results from thermal emission measurements with those from absorption spectra of the moon taken at the same time, as well as an error analysis, are presented. The inferred propagation speed from sequential images is used in a subsequent paper (Part 2 to calculate the emission rates at different distances from the crater.

  12. Enhancement of white-light-emission from single-phase Sr5(PO4)3F:Eu(2+),Mn(2+) phosphors for near-UV white LEDs.

    Science.gov (United States)

    Feng, Yaomiao; Huang, Jinping; Liu, Lili; Liu, Jie; Yu, Xibin

    2015-09-07

    A series of single-phase broadband white-light-emitting Sr5(PO4)3F:Eu(2+),Mn(2+) phosphors were prepared by a solid state reaction. The luminescence property, and the crystal and electronic structures of the fluorophosphates were studied by photoluminescence analysis, XRD Rietveld refinement and density functional theory calculation (DFT), respectively. Under near ultraviolet excitation in the 250 to 430 nm wavelength range, the phosphors exhibit two emission bands centered at 440 and 556 nm, caused by the Eu(2+) and Mn(2+) ions. By altering the relative ratios of Eu(2+) and Mn(2+) in the compounds, the emission color could be modulated from blue to white. The efficient energy transfer from the Eu(2+) to Mn(2+) ions could be ascribed to the well crystallized host lattice and the facile substitution of Eu(2+) and Mn(2+) for Sr(2+) sites due to similar ionic radii. A series of fluxes were investigated to improve the photoluminescence intensity. When KCl was used as flux in the synthesis, the photoluminescence intensity of Sr5(PO4)3F:Eu(2+),Mn(2+) was enhanced by 85% compared with no fluxes added. These results demonstrate that the single-phase Sr5(PO4)3F:Eu(2+),Mn(2+) with enhanced luminescence efficiency could be promising as a near UV-convertible direct white-light-emitting phosphor for WLED applications.

  13. UV-LED Curing Efficiency of Wood Coatings

    OpenAIRE

    Véronic Landry; Pierre Blanchet; Gabrielle Boivin; Jean-François Bouffard; Mirela Vlad

    2015-01-01

    Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerf...

  14. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  15. ALMA constraints on star-forming gas in a prototypical z = 1.5 clumpy galaxy: the dearth of CO(5-4) emission from UV-bright clumps

    Science.gov (United States)

    Cibinel, A.; Daddi, E.; Bournaud, F.; Sargent, M. T.; le Floc'h, E.; Magdis, G. E.; Pannella, M.; Rujopakarn, W.; Juneau, S.; Zanella, A.; Duc, P.-A.; Oesch, P. A.; Elbaz, D.; Jagannathan, P.; Nyland, K.; Wang, T.

    2017-08-01

    We present deep ALMA CO(5-4) observations of a main-sequence, clumpy galaxy at z = 1.5 in the HUDF. Thanks to the ˜0{^''.}5 resolution of the ALMA data, we can link stellar population properties to the CO(5-4) emission on scales of a few kiloparsec. We detect strong CO(5-4) emission from the nuclear region of the galaxy, consistent with the observed LIR-L^' }_CO(5-4) correlation and indicating ongoing nuclear star formation. The CO(5-4) gas component appears more concentrated than other star formation tracers or the dust distribution in this galaxy. We discuss possible implications of this difference in terms of star formation efficiency and mass build-up at the galaxy centre. Conversely, we do not detect any CO(5-4) emission from the UV-bright clumps. This might imply that clumps have a high star formation efficiency (although they do not display unusually high specific star formation rates) and are not entirely gas dominated, with gas fractions no larger than that of their host galaxy (˜50 per cent). Stellar feedback and disc instability torques funnelling gas towards the galaxy centre could contribute to the relatively low gas content. Alternatively, clumps could fall in a more standard star formation efficiency regime if their actual star formation rates are lower than generally assumed. We find that clump star formation rates derived with several different, plausible methods can vary by up to an order of magnitude. The lowest estimates would be compatible with a CO(5-4) non-detection even for main-sequence like values of star formation efficiency and gas content.

  16. Properties of C4F7N–CO2 thermal plasmas: thermodynamic properties, transport coefficients and emission coefficients

    Science.gov (United States)

    Wu, Yi; Wang, Chunlin; Sun, Hao; Murphy, Anthony B.; Rong, Mingzhe; Yang, Fei; Chen, Zhexin; Niu, Chunpin; Wang, Xiaohua

    2018-04-01

    The thermophysical properties, including composition, thermodynamic properties, transport coefficients and net emission coefficients, of thermal plasmas formed from pure iso-C4 perfluoronitrile C4F7N and C4F7N–CO2 mixtures are calculated for temperatures from 300 to 30 000 K and pressures from 0.1 to 20 atm. These gases have received much attention as alternatives to SF6 for use in circuit breakers, due to the low global warming potential and good dielectric properties of C4F7N. Since the parameters of the large molecules formed in the dissociation of C4F7N are unavailable, the partition function and enthalpy of formation were calculated using computational chemistry methods. From the equilibrium composition calculations, it was found that when C4F7N is mixed with CO2, CO2 can capture C atoms from C4F7N, producing CO, since the system consisting of small molecules such as CF4 and CO has lower energy at room temperature. This is in agreement with previous experimental results, which show that CO dominates the decomposition products of C4F7N–CO2 mixtures; it could limit the repeated breaking performance of C4F7N. From the point of view of chemical stability, the mixing ratio of CO2 should therefore be chosen carefully. Through comparison with common arc quenching gases (including SF6, CF3I and C5F10O), it is found that for the temperature range for which electrical conductivity remains low, pure C4F7N has similar ρC p (product of mass density and specific heat) properties to SF6, and higher radiative emission coefficient, properties that are correlated with good arc extinguishing capability. For C4F7N–CO2 mixtures, the electrical conductivity is very close to that of SF6 while the ρC p peak at 7000 K caused by decomposition of CO implies inferior interruption capability to that of SF6. The calculated properties will be useful in arc simulations.

  17. A low-order model of water vapor, clouds, and thermal emission for tidally locked terrestrial planets

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jun; Abbot, Dorian S., E-mail: junyang28@uchicago.edu [Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 (United States)

    2014-04-01

    In the spirit of minimal modeling of complex systems, we develop an idealized two-column model to investigate the climate of tidally locked terrestrial planets with Earth-like atmospheres in the habitable zone of M-dwarf stars. The model is able to approximate the fundamental features of the climate obtained from three-dimensional (3D) atmospheric general circulation model (GCM) simulations. One important reason for the two-column model's success is that it reproduces the high cloud albedo of the GCM simulations, which reduces the planet's temperature and delays the onset of a runaway greenhouse state. The two-column model also clearly illustrates a secondary mechanism for determining the climate: the nightside acts as a 'radiator fin' through which infrared energy can be lost to space easily. This radiator fin is maintained by a temperature inversion and dry air on the nightside, and plays a similar role to the subtropics on modern Earth. Since one-dimensional radiative-convective models cannot capture the effects of the cloud albedo and radiator fin, they are systematically biased toward a narrower habitable zone. We also show that cloud parameters are the most important in the two-column model for determining the day-night thermal emission contrast, which decreases and eventually reverses as the stellar flux increases. This reversal is important because it could be detected by future extrasolar planet characterization missions, which would suggest that the planet has Earth-like water clouds and is potentially habitable.

  18. A LINGERING NON-THERMAL COMPONENT IN THE GAMMA-RAY BURST PROMPT EMISSION: PREDICTING GeV EMISSION FROM THE MeV SPECTRUM

    International Nuclear Information System (INIS)

    Basak, Rupal; Rao, A. R.

    2013-01-01

    The high-energy GeV emission of gamma-ray bursts (GRBs) detected by Fermi/LAT has a significantly different morphology compared to the lower energy MeV emission detected by Fermi/GBM. Though the late-time GeV emission is believed to be synchrotron radiation produced via an external shock, this emission as early as the prompt phase is puzzling. A meaningful connection between these two emissions can be drawn only by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the Gamma-ray Burst Monitor (GBM) data of long GRBs with significant GeV emission, using a model consisting of two blackbodies and a power law. We examine in detail the evolution of the spectral components and find that GRBs with high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component in the GBM spectrum, which lingers at the later part of the prompt emission. This behavior mimics the flux evolution in the Large Area Telescope (LAT). In contrast, bright GBM GRBs with an order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson correlation: r = 0.88 and Spearman correlation: ρ = 0.81). We demonstrate that this correlation is not influenced by the correlation between the total and the power-law fluences at a confidence level of 2.3σ. We speculate the possible radiation mechanisms responsible for the correlation

  19. Non-relativistic Free–Free Emission due to the n -distribution of Electrons—Radiative Cooling and Thermally Averaged and Total Gaunt Factors

    Energy Technology Data Exchange (ETDEWEB)

    De Avillez, Miguel A. [Department of Mathematics, University of Évora, R. Romão Ramalho 59, 7000 Évora (Portugal); Breitschwerdt, Dieter, E-mail: mavillez@galaxy.lca.uevora.pt [Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstrasse 36, D-10623 Berlin (Germany)

    2017-09-01

    Tracking the thermal evolution of plasmas, characterized by an n -distribution, using numerical simulations, requires the determination of the emission spectra and of the radiative losses due to free–free emission from the corresponding temperature-averaged and total Gaunt factors. Detailed calculations of the latter are presented and associated with n -distributed electrons with the parameter n ranging from 1 (corresponding to the Maxwell–Boltzmann distribution) to 100. The temperature-averaged and total Gaunt factors with decreasing n tend toward those obtained with the Maxwell–Boltzmann distribution. Radiative losses due to free–free emission in a plasma evolving under collisional ionization equilibrium conditions and composed by H, He, C, N, O, Ne, Mg, Si, S, and Fe ions, are presented. These losses decrease with a decrease in the parameter n , reaching a minimum when n  = 1, and thus converge with the loss of thermal plasma. Tables of the thermal-averaged and total Gaunt factors calculated for n -distributions, and a wide range of electron and photon energies, are presented.

  20. Non-relativistic Free–Free Emission due to the n -distribution of Electrons—Radiative Cooling and Thermally Averaged and Total Gaunt Factors

    International Nuclear Information System (INIS)

    De Avillez, Miguel A.; Breitschwerdt, Dieter

    2017-01-01

    Tracking the thermal evolution of plasmas, characterized by an n -distribution, using numerical simulations, requires the determination of the emission spectra and of the radiative losses due to free–free emission from the corresponding temperature-averaged and total Gaunt factors. Detailed calculations of the latter are presented and associated with n -distributed electrons with the parameter n ranging from 1 (corresponding to the Maxwell–Boltzmann distribution) to 100. The temperature-averaged and total Gaunt factors with decreasing n tend toward those obtained with the Maxwell–Boltzmann distribution. Radiative losses due to free–free emission in a plasma evolving under collisional ionization equilibrium conditions and composed by H, He, C, N, O, Ne, Mg, Si, S, and Fe ions, are presented. These losses decrease with a decrease in the parameter n , reaching a minimum when n  = 1, and thus converge with the loss of thermal plasma. Tables of the thermal-averaged and total Gaunt factors calculated for n -distributions, and a wide range of electron and photon energies, are presented.

  1. Memory effect driven emissions of persistent organic pollutants from industrial thermal processes, their implications and management: a review.

    Science.gov (United States)

    Trivedi, Jitendra; Majumdar, Deepanjan

    2013-04-15

    Memory effect is delayed emission of certain persistent organic pollutants (POPs). Many of the POP compounds viz. polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) get trapped in the particulate phase deposited in the flue transfer lines and air pollution control systems (equivalent to storage in the memory of a system) and released subsequently. Memory effect driven emission is a combination of real time emission and emission of stored compounds and so is not a true measure of actual real time emission. Memory effect is now realized to have existed for a long time but was not identified and understood until recently. Memory effect has several serious implications e.g. it wrongly depicts emission patterns of POPs; it makes compliance to stipulated emission standards difficult; it could lead to wrong calculations of emission factors and emission inventory estimates of a plant and leads to misinterpretation of efficacy of processes and air pollution control systems. Further, new PCDD/Fs may be formed in the trapped particulate phase via de novo synthesis and the new compounds may be emitted, thereby increasing total PCDD/F emissions, apart from altering the homologue pattern of PCDD/Fs in emissions. Memory effect could be minimized by judicious operational and management (O&M) procedures like optimizing combustion, minimizing unnecessary halts in operations, periodical cleaning of flue transfer lines, application of inhibitors etc. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Characterization of dynamic thermal control schemes and heat transfer pathways for incorporating variable emissivity electrochromic materials into a space suit heat rejection system

    Science.gov (United States)

    Massina, Christopher James

    The feasibility of conducting long duration human spaceflight missions is largely dependent on the provision of consumables such as oxygen, water, and food. In addition to meeting crew metabolic needs, water sublimation has long served as the primary heat rejection mechanism in space suits during extravehicular activity (EVA). During a single eight hour EVA, approximately 3.6 kg (8 lbm) of water is lost from the current suit. Reducing the amount of expended water during EVA is a long standing goal of space suit life support systems designers; but to date, no alternate thermal control mechanism has demonstrated the ability to completely eliminate the loss. One proposed concept is to convert the majority of a space suit's surface area into a radiator such that the local environment can be used as a radiative thermal sink for rejecting heat without mass loss. Due to natural variations in both internal (metabolic) loads and external (environmental) sink temperatures, radiative transport must be actively modulated in order to maintain an acceptable thermal balance. Here, variable emissivity electrochromic devices are examined as the primary mechanism for enabling variable heat rejection. This dissertation focuses on theoretical and empirical evaluations performed to determine the feasibility of using a full suit, variable emissivity radiator architecture for space suit thermal control. Operational envelopes are described that show where a given environment and/or metabolic load combination may or may not be supported by the evaluated thermal architecture. Key integration considerations and guidelines include determining allowable thermal environments, defining skin-to-radiator heat transfer properties, and evaluating required electrochromic performance properties. Analysis also considered the impacts of dynamic environmental changes and the architecture's extensibility to EVA on the Martian surface. At the conclusion of this work, the full suit, variable emissivity

  3. UV-induced photoluminescence and thermally stimulated luminescence of CaSO{sub 4}:Eu and CaF{sub 2}:Tb{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Godbole, S.V.; Nagpal, J.S.; Page, A.G. E-mail: agpage@magnum.barc.ernet.in

    2000-08-15

    Ultraviolet radiation induced changes in photoluminescence (PL) and thermally stimulated luminescence (TSL) of europium activated calcium sulphate (CaSO{sub 4}:Eu{sup 3+}, Eu{sup 2+}) and terbium doped calcium fluoride (CaF{sub 2}:Tb{sup 3+}) phosphors have been studied. PL measurements suggest conversion of Eu{sup 3+} to Eu{sup 2+} on 254 nm irradiation corresponding to charge transfer band of Eu{sup 3+} ions and reduction of Eu{sup 2+} ions with 365 nm illumination representing a f-d transition of Eu{sup 2+} ions. Similar studies carried out on CaF{sub 2}:Tb{sup 3+} phosphor, however, do not show any significant wavelength specific changes. The integrated TSL output appears to be rate-dependent for both phosphors. The wavelength dependent changes in TSL output observed for CaSO{sub 4}:Eu phosphor have been correlated with those obtained in PL studies. The changes in TSL and PL characteristics of CaF{sub 2}:Tb{sup 3+} phosphor have been explained on the basis of stabilisation of traps based on matrix specific charge similarities.

  4. Quasi-simultaneous observations of BL Lac object Mrk 501 in X-ray, UV, visible, IR, and radio frequencies

    Science.gov (United States)

    Kondo, Y.; Worrall, D. M.; Oke, J. B.; Yee, H. K. C.; Neugebauer, G.; Matthews, K.; Feldman, P. A.; Mushotzky, R. F.; Hackney, R. L.; Hackney, K. R. H.

    1981-01-01

    Observations in the X-ray, UV, visible, IR and radio regions of the BL Lac object Mrk 501 made over the course of two months are reported. The measurements were made with the A2 experiment on HEAO 1 (X-ray), the SWP and LWR cameras on IUE (UV), the 5-m Hale telescope (visible), the 2.5-m telescope at Mount Wilson (IR), the NRAO 92-m radio telescope at Green Bank (4750 MHz) and the 46-m radio telescope at the Algonquin Observatory (10275 and 10650 MHz). The quasi-simultaneously observed spectral slope is found to be positive and continuous from the X-ray to the UV, but to gradually flatten and possibly turn down from the mid-UV to the visible; the optical-radio emission cannot be accounted for by a single power law. The total spectrum is shown to be compatible with a synchrotron self-Compton emission mechanism, while the spectrum from the visible to the X-ray is consistent with synchrotron radiation or inverse-Compton scattering by a hot thermal electron cloud. The continuity of the spectrum from the UV to the X-ray is noted to imply a total luminosity greater than previous estimates by a factor of 3-4.

  5. Seasonal and Non-Seasonal Variations of Jupiter's Atmosphere from Observations of Thermal Emission, 1994-2011

    Science.gov (United States)

    Orton, G.; Fletcher, L.; Yanamandra-Fisher, P.; Greathouse, T.; Fisher, B.; Greco, J.; Wakefield, L.; Snead, E.; Boydstun, K.; Simon-Miller, A.; hide

    2012-01-01

    We analyzed mid-infrared images of Jupiter's thermal emission, covering approx.1.5 Jovian years, acquired in discrete filters between 7.8 and 24.5 microns. The behavior of stratospheric (approx.10-mbar) and tropospheric (approx.100-400 mbar) temperatures is generally consistent with predictions of seasonal variability, with differences between 100-mbar temperatures +/-50-60deg from the equator on the order of +/-2. Removing this effect, there appear to be long-term quasi-periodic variability of tropospheric temperatures, whose amplitude, phase and period depend on latitude. The behavior of temperatures in the Equatorial Zone (EZ) suggests a approx.4-6-year period with amplitude of about +/-1-1.5 K in temperature. At mid-latitudes, the periodicity is more distinct with amplitudes around +/-1.5-2.5 K and 4-8 year periods. The 4.2-year variation of stratospheric temperatures known as the quasiquadrennial oscillation or "QQO" (Leovy et al. 1991, Nature 354, 380) continued during this period. There were no variations of zonal mean temperatures associated with any of the "global upheaval" events that have produced dramatic changes of jupiter's visible appearance and cloud cover, although there are colder discrete regions associated with updrafts, e.g. the early stages of the re-darkening ("revival") of the South Equatorial Belt (SEB) in late 2010. On the other hand increases in the visible albedos ("fades") of belts are accompanied by increases in the thickness of a 700-mbar cloud layer (most likely NH3 ice) and clouds at higher pressures, together with the mixing ratio of NH3 gas near 400 mbar (above its condensation level). These quantities decrease during re-darkening ("revival") episodes, during which we note discrete features that are exceptions to the general correlation between dark albedos and minimal cloudiness. In contrast to all these changes, the meridional distribution of the 240-mbar para-H2 fraction appears to be invariant in time.

  6. Recommendations on the choice of gas analysis equipment for systems of continuous monitoring and accounting of emissions from thermal power plants

    Science.gov (United States)

    Kondrat'eva, O. E.; Roslyakov, P. V.; Burdyukov, D. A.; Khudolei, O. D.; Loktionov, O. A.

    2017-10-01

    According to Federal Law no. 219-FZ, dated July 21, 2014, all enterprises that have a significant negative impact on the environment shall continuously monitor and account emissions of harmful substances into the atmospheric air. The choice of measuring equipment that is included in continuous emission monitoring and accounting systems (CEM&ASs) is a complex technical problem; in particular, its solution requires a comparative analysis of gas analysis systems; each of these systems has its advantages and disadvantages. In addition, the choice of gas analysis systems for CEM&ASs should be maximally objective and not depend on preferences of separate experts and specialists. The technique of choosing gas analysis equipment that was developed in previous years at Moscow Power Engineering Institute (MPEI) has been analyzed and the applicability of the mathematical tool of a multiple criteria analysis to choose measuring equipment for the continuous emission monitoring and accounting system have been estimated. New approaches to the optimal choice of gas analysis equipment for systems of the continuous monitoring and accounting of harmful emissions from thermal power plants have been proposed, new criteria of evaluation of gas analysis systems have been introduced, and weight coefficients have been determined for these criteria. The results of this study served as a basis for the Preliminary National Standard of the Russian Federation "Best Available Technologies. Automated Systems of Continuous Monitoring and Accounting of Emissions of Harmful (Polluting) Substances from Thermal Power Plants into the Atmospheric Air. Basic Requirements," which was developed by the Moscow Power Engineering Institute, National Research University, in cooperation with the Council of Power Producers and Strategic Electric Power Investors Association and the All-Russia Research Institute for Materials and Technology Standardization.

  7. Design of geometry, synthesis, spectroscopic (FT-IR, UV/Vis, excited state, polarization) and anisotropy (thermal conductivity and electrical) properties of new synthesized derivatives of (E,E)-azomethines in colored stretched poly (vinyl alcohol) matrix

    Science.gov (United States)

    Shahab, Siyamak; Sheikhi, Masoome; Filippovich, Liudmila; Dikusar, Evgenij; Yahyaei, Hooriye; Kumar, Rakesh; Khaleghian, Mehrnoosh

    2018-04-01

    In the present work, the molecular structures of two new azomethine dyes: have been predicted and investigated using Density Functional Theory (DFT) in dimethylformamide (DMF). The geometries of the azomethine dyes were optimized by B3LYP/6-31+G* level of theory. The electronic spectra of these azomethine dyes in a DMF solvent was carried out by using TD-B3LYP/6-31+G* method. After quantum-chemical calculations two new azomethine dyes for optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. The computed absorption spectral data of the azomethine dyes are in good agreement with the experimental data, thus allowing an assignment of the UV/Vis spectra. On the basis of polyvinyl alcohol (PVA) and the new synthesized azomethine dyes polarizing films for visible region of spectrum were developed. The main optical parameters of the polarizing PVA-films (Transmittance, Polarization Efficiency and Dichroic Ratio) have been measured and discussed. Anisotropy of thermal and electrical conductivity of the PVA-films have been studied and explained.

  8. Effect of thermal annealing on the optical and structural properties of silicon implanted with a high hydrogen fluence

    International Nuclear Information System (INIS)

    Kling, A.; Soares, J.C.; Rodriguez, A.; Rodriguez, T.; Avella, M.; Jimenez, J.

    2006-01-01

    Silicon capped by thermal oxide has been implanted with 1 x 10 17 H/cm 2 and the implant profile peaking at the interface. Samples were subjected to thermal annealing and characterized by ERD, FTIR, RBS/channeling, UV/VIS reflectance and cathodoluminescence regarding H-content, crystalline quality and light emission. The results show that the luminescent properties are independent of the hydrogen content but are strongly related with the present damage

  9. Realizing Highly Efficient Solution-Processed Homojunction-Like Sky-Blue OLEDs by Using Thermally Activated Delayed Fluorescent Emitters Featuring an Aggregation-Induced Emission Property.

    Science.gov (United States)

    Wu, Kailong; Wang, Zian; Zhan, Lisi; Zhong, Cheng; Gong, Shaolong; Xie, Guohua; Yang, Chuluo

    2018-04-05

    Two new blue emitters, i.e., bis-[2-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone ( o-ACSO2) and bis-[3-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone ( m-ACSO2), with reserved fine thermally activated delayed fluorescent (TADF) nature and simply tuned thermal and optoelectronic properties, were synthesized by isomer engineering. The meta-linking compound, i.e., m-ACSO2, obtains the highest photoluminescence quantum yield with a small singlet-triplet energy gap, a moderate delayed fluorescent lifetime, excellent solubility, and neat film homogeneity. Due to its unique aggregation-induced emission (AIE) character, neat film-based heterojunction-like organic light-emitting diodes (OLEDs) are achievable. By inserting an excitonic inert exciton-blocking layer, the PN heterojunction-like emission accompanied by intefacial exciplex was shifted to a homojunction-like channel mainly from the AIE emitter itself, providing a new tactic to generate efficient blue color from neat films. The solution-processed nondoped sky-blue OLED employing m-ACSO2 as emitter with homojunction-like emission achieved a maximum external quantum efficiency of 17.2%. The design strategies presented herein provide practical methods to construct efficient blue TADF dyes and realize high-performance blue TADF devices.

  10. Broadband white light emission from Ce:AlN ceramics: High thermal conductivity down-converters for LED and laser-driven solid state lighting

    Directory of Open Access Journals (Sweden)

    A. T. Wieg

    2016-12-01

    Full Text Available We introduce high thermal conductivity aluminum nitride (AlN as a transparent ceramic host for Ce3+, a well-known active ion dopant. We show that the Ce:AlN ceramics have overlapping photoluminescent (PL emission peaks that cover almost the entire visible range resulting in a white appearance under 375 nm excitation without the need for color mixing. The PL is due to a combination of intrinsic AlN defect complexes and Ce3+ electronic transitions. Importantly, the peak intensities can be tuned by varying the Ce concentration and processing parameters, causing different shades of white light without the need for multiple phosphors or light sources. The Commission Internationale de l’Eclairage coordinates calculated from the measured spectra confirm white light emission. In addition, we demonstrate the viability of laser driven white light emission by coupling the Ce:AlN to a readily available frequency tripled Nd-YAG laser emitting at 355 nm. The high thermal conductivity of these ceramic down-converters holds significant promise for producing higher power white light sources than those available today.

  11. Project for solving of environmental problems caused by ash emission and deposition from the thermal power plant 'Nikola Tesla' at Obrenovac

    International Nuclear Information System (INIS)

    Simonovic, B.R.; Vukmirovic, Z.; Ilic, M.

    2002-01-01

    The problem of ash emission and deposition from the Thermal Power Plant 'Nikola Tesla' (TPPNT) in Obrenovac commences with the date of their construction. Up to now, mainly, some analysis of several possible influences of ash (emitted or deposited on the ash and slug dump) was done. We believe that is time now, due to the consequences for a long time, to pose and to resolve the whole problem of ash emission and deposition from TPPNT Obrenovac. Due to the very big production capacity, an enormous amount of fly ash (particle size of 90-200 μm) is emitted to a large area near Obrenovac. Very large quantities of ash and slug (more than 2 millions tons annually) produced during coal burning were deposited on the dump very close to the river Sava. Some of the multiple consequences due to elution of heavy metals, water spilling from the dump and mixing with ground water and surface water of river Sava, weathering of fine particles of ash by wind, acid rains near to the thermal power plants, and other influences of flying and deposited ash on the environment of the whole area are always present. Due to the complexity of the posed problem, a multidisciplinary experts' team was formed to cover all aspects of negative influences of ash emission and deposition from TPPNT Obrenovac. Our project comprises a large number of subprojects covering different problem solving, diminution or removal of all negative influences according to European standards and regulations. (author)

  12. Using Lava Tube Skylight Thermal Emission Spectra to Determine Lava Composition on Io: Quantitative Constraints for Observations by Future Missions to the Jovian System.

    Science.gov (United States)

    Davies, A. G.

    2008-12-01

    Deriving the composition of Io's dominant lavas (mafic or ultramafic?) is a major objective of the next missions to the jovian system. The best opportunities for making this determination are from observations of thermal emission from skylights, holes in the roof of a lava tube through which incandescent lava radiates, and Io thermal outbursts, where lava fountaining is taking place [1]. Allowing for lava cooling across the skylight, the expected thermal emission spectra from skylights of different sizes have been calculated for laminar and turbulent tube flow and for mafic and ultramafic composition lavas. The difference between the resulting mafic and ultramafic lava spectra has been quantified, as has the instrument sensitivity needed to acquire the necessary data to determine lava eruption temperature, both from Europa orbit and during an Io flyby. A skylight is an excellent target to observe lava that has cooled very little since eruption (California Institute of Technology, under contract to NASA. AGD is supported by a grant from the NASA OPR Program. References: [1] Davies, A. G., 1996, Icarus, 124, 45-61. [2] Keszthelyi, L., et al., 2006, JGS, 163, 253-264. [3] Davies, A. G., 2007, Volcanism on Io, Cambridge University Press. [4] Keszthelyi, L., et al., 2007, Icarus, 192, 491-502. [5] Davies, A. G., et al., 2006, Icarus, 184, 460-477.

  13. Reassessment of the temperature-emissivity separation from multispectral thermal infrared data: Introducing the impact of vegetation canopy by simulating the cavity effect with the SAIL-Thermique model

    Science.gov (United States)

    We investigated the use of multispectral thermal imagery to retrieve land surface emissivity and temperature. Conversely to concurrent methods, the temperature emissivity separation (TES) method simply requires single overpass without any ancillary information. This is possible since TES makes use o...

  14. Europium-activated barium/strontium silicates for near-UV light emitting diode applications

    Energy Technology Data Exchange (ETDEWEB)

    Han, J.K. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); Hannah, M.E.; Piquette, A. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); Micone, J. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); Hirata, G.A. [Centro de Nanociencias y Nanotecnolgia, Universidad Nacional Autonoma de Mexico, Km. 107 Carretera Tijuana-Ensenada Apdo, Ensenada, MX CP 22860 (Mexico); Talbot, J.B. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Nanoengineering, La Jolla, CA 92093 (United States); Mishra, K.C. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); McKittrick, J., E-mail: jmckittrick@UCSD.Edu [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Mechanical and Aerospace Engineering, La Jolla, CA 92093 (United States)

    2013-01-15

    This paper reports on the luminescence properties of submicron-sized green-yellow emitting (Ba{sub 1-x}Sr{sub x}Eu{sub 0.03}){sub 2}SiO{sub 4} (0{<=}x{<=}1) phosphors. These phosphors were prepared by a modified sol-gel/Pechini method. The X-ray diffraction analysis shows that the single phase products are obtained. The particle size - ranges from 200 to 500 nm with a spherical or needlelike shape depending on x. These phosphors show strong absorption in the near UV range and the photoluminescence emission spectra consist of a strong broad green-yellow band centered between 512 and 570 nm, depending on x. Furthermore, the phosphors have high quantum efficiencies: 94% for x=0 and 85% for x=0.25. The emission lifetime at 400 K is 97% of that at 40 K, demonstrating good thermal stability. - Highlights: Black-Right-Pointing-Pointer (Ba{sub 1-x}Sr{sub x}Eu{sub 0.03}){sub 2}SiO{sub 4} (0{<=}x{<=}1) phosphors were prepared by a sol-gel/Pechini method. Black-Right-Pointing-Pointer Submicron-sized (200-500 nm) particle had a spherical or needlelike morphology. Black-Right-Pointing-Pointer Strong absorption and high quantum efficiencies (85-94%) in the near UV range. Black-Right-Pointing-Pointer Emission lifetime at 400 K is 97% of that at 40 K, showing good thermal stability.

  15. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  16. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  17. Thermal disposal of sewage sludges by fluidised bed combustion with low emissions of pollutants. Thermische Entsorgung kommunaler Klaerschlaemme durch schadstoffarme Verbrennung in der Wirbelschicht

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, B. (Technische Univ. Magdeburg (Germany). Inst. fuer Thermische Apparate- und Umwelttechnik, Abt. Umwelttechnik); Lindau, S. (Technische Univ. Magdeburg (Germany). Inst. fuer Thermische Apparate- und Umwelttechnik, Abt. Umwelttechnik); Busse, U. (Technische Univ. Magdeburg (Germany). Inst. fuer Thermische Apparate- und Umwelttechnik, Abt. Umwelttechnik)

    1992-04-01

    The volume of sludge from the sewage treatment represents the largest problem in the waste management in Germany recently. The thermal treatment is inevitable for the solution of the problem. The fluidised bed combustion is suitable for a very good usability of sewage sludge. Experimental investigations carried out in a stationary fluidised bed in laboratory scale. The emissions of gaseous air pollutants are influenced by the properties of the sludge and the parameters of the process. The dependence of the formation and the reactions of the pollutants from various parameters are analysed and judged. (orig.)

  18. Mercury Emissions Capture Efficiency with Activated Carbon Injection at a Russian Coal-Fired Thermal Power Plant

    Science.gov (United States)

    This EPA-led project, conducted in collaboration with UNEP, the Swedish Environmental Institute and various Russian Institutes, that demonstrates that the mercury emission control efficiencies of activated carbon injection technologies applied at a Russian power plant burning Rus...

  19. Investigation of UV-LED Initiated Photopolymerisation of Bio-compatible HEMA

    OpenAIRE

    McDermott, Sharon

    2008-01-01

    Ultraviolet (UV) fluorescent lamps are widely used in photopolymerisation processes. However, there a number of disadvantages to these lamps, namely, their intensity varies over time and has to be constantly monitored. This thesis is concerned with the possibility of replacing these lamps with UV Light Emitting Diodes (UV-LEDs). A number of emission characteristics of both the fluorescent lamp and the UV-LEDs were measured and compared to ensure that the optical properties of the UV-LEDs were...

  20. Air Emissions Sampling from Vacuum Thermal Desorption for Mixed Wastes Designated with a Combustion Treatment Code for the Energy Solutions LLC Mixed Waste Facility

    International Nuclear Information System (INIS)

    Christensen, M.E.; Willoughby, O.H.

    2009-01-01

    EnergySolutions LLC is permitted by the State of Utah to treat organically-contaminated Mixed Waste by a vacuum thermal desorption (VTD) treatment process at its Clive, Utah treatment, storage, and disposal facility. The VTD process separates organics from organically-contaminated waste by heating the material in an inert atmosphere, and captures them as concentrated liquid by condensation. The majority of the radioactive materials present in the feed to the VTD are retained with the treated solids; the recovered aqueous and organic condensates are not radioactive. This is generally true when the radioactivity is present in solid form such as inorganic salts, metals or metallic oxides. The exception is when volatile radioactive materials are present such as radon gas, tritium, or carbon-14 organic chemicals. Volatile radioactive materials are a small fraction of the feed material. On August 28, 2006, EnergySolutions submitted a request to the USEPA for a variance to the Land Disposal Restrictions (LDR) standards for wastes designated with the combustion treatment code (CMBST). The final rule granting a site specific treatment variance was effective June 13, 2008. This variance is an alternative treatment standard to treatment by CMBST required for these wastes under USEPA's rules. The State of Utah provides oversight of the VTD processing operations. A demonstration test for treating CMBST-coded wastes was performed on April 29, 2008 through May 1, 2008. Three separate process cycles were conducted during this test. Both solid/liquid samples and emission samples were collected each day during the demonstration test. To adequately challenge the unit, feed material was spiked with trichloroethylene, o-cresol, dibenzofuran, and coal tar. Emission testing was conducted by EnergySolutions' emissions test contractor and sampling for radioactivity within the off-gas was completed by EnergySolutions' Health Physics department. This report discusses the emission testing

  1. ULTRAVIOLET AND EXTREME-ULTRAVIOLET EMISSIONS AT THE FLARE FOOTPOINTS OBSERVED BY ATMOSPHERE IMAGING ASSEMBLY

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Jiong; Longcope, Dana W.; Liu Wenjuan [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Sturrock, Zoe [Department of Applied Mathematics, University of St. Andrews (United Kingdom); Klimchuk, James A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-09-01

    A solar flare is composed of impulsive energy release events by magnetic reconnection, which forms and heats flare loops. Recent studies have revealed a two-phase evolution pattern of UV 1600 A emission at the feet of these loops: a rapid pulse lasting for a few seconds to a few minutes, followed by a gradual decay on timescales of a few tens of minutes. Multiple band EUV observations by the Atmosphere Imaging Assembly further reveal very similar signatures. These two phases represent different but related signatures of an impulsive energy release in the corona. The rapid pulse is an immediate response of the lower atmosphere to an intense thermal conduction flux resulting from the sudden heating of the corona to high temperatures (we rule out energetic particles due to a lack of significant hard X-ray emission). The gradual phase is associated with the cooling of hot plasma that has been evaporated into the corona. The observed footpoint emission is again powered by thermal conduction (and enthalpy), but now during a period when approximate steady-state conditions are established in the loop. UV and EUV light curves of individual pixels may therefore be separated into contributions from two distinct physical mechanisms to shed light on the nature of energy transport in a flare. We demonstrate this technique using coordinated, spatially resolved observations of UV and EUV emissions from the footpoints of a C3.2 thermal flare.

  2. 210Po and 210Pb emissions to air from the thermal phosphorus plant in Europe: measurements in the environment and dose assessment for regulatory purpose

    International Nuclear Information System (INIS)

    Tanzi, C.P.; Knetsch, G.J.

    2013-01-01

    In 1983 in The Netherlands, an environmental survey at a river estuary revealed elevated radionuclide concentrations above the background level. The source was identified as an industrial plant producing elemental phosphorus, by means of a thermal process. Within a few years a permit for emissions of radionuclides to the environment was requested under the prevailing Nuclear Energy Act, and granted. Since 1987 the industry reports its emission data to the mandated Ministry. This phosphorus plant contributes the highest release of 210 Po and 210 Pb to air in the Netherlands. The difficulty of identifying the enhanced activity due to the elemental phosphorus through environmental measurement is here illustrated by showing, by means of an air dispersion model, that the radioactivity added by the phosphorus plant to the environment is comparable to the natural background level. The estimate of the excess air concentration given exclusively by a continuous annual emission of 500 GBq, bound to aerosols of size less than 1 micron, varies from 450 to 750 micro Bq/m 3 at a distance of 3.5 km from the phosphorus plant, depending on yearly weather variations. This may be compared to the natural background level as it is measured at a distance of over 100 km inland from the phosphorus plant, at RIVM, the National Institute for Public Health and the Environment. The yearly average measured 210 Pb activity concentration in air is 363±5 micro Bq/m 3 in 2009 which is within range of other years. At the coastal site where the phosphorus plant is located, the natural background will be lower. The gross beta activity concentration near the phosphorus plant is 296 micro Bq/m 3 in 2009: this includes the emissions to air from the sintering process. The emission to air for the year 2009 reported by the phosphorus plan is 80 GBq/y of 210 Pb

  3. CORE-COLLAPSE MODEL OF BROADBAND EMISSION FROM SNR RX J1713.7–3946 WITH THERMAL X-RAYS AND GAMMA RAYS FROM ESCAPING COSMIC RAYS

    International Nuclear Information System (INIS)

    Ellison, Donald C.; Slane, Patrick; Patnaude, Daniel J.; Bykov, Andrei M.

    2012-01-01

    We present a spherically symmetric, core-collapse model of SNR RX J1713.7–3946 that includes a hydrodynamic simulation of the remnant evolution coupled to the efficient production of cosmic rays (CRs) by nonlinear diffusive shock acceleration. High-energy CRs that escape from the forward shock (FS) are propagated in surrounding dense material that simulates either a swept-up, pre-supernova shell or a nearby molecular cloud. The continuum emission from trapped and escaping CRs, along with the thermal X-ray emission from the shocked heated interstellar medium behind the FS, integrated over the remnant, is compared against broadband observations. Our results show conclusively that, overall, the GeV-TeV emission is dominated by inverse-Compton from CR electrons if the supernova is isolated regardless of its type, i.e., not interacting with a >>100 M ☉ shell or cloud. If the supernova remnant is interacting with a much larger mass ∼> 10 4 M ☉ , pion decay from the escaping CRs may dominate the TeV emission, although a precise fit at high energy will depend on the still uncertain details of how the highest energy CRs are accelerated by, and escape from, the FS. Based on morphological and other constraints, we consider the 10 4 M ☉ pion-decay scenario highly unlikely for SNR RX J1713.7–3946 regardless of the details of CR escape. Importantly, even though CR electrons dominate the GeV-TeV emission, the efficient production of CR ions is an essential part of our leptonic model.

  4. Calculations of total fusion power and spatial distribution of emissivity for a D-T thermal plasma

    International Nuclear Information System (INIS)

    Batistoni, P.; Pillon, M.

    1987-01-01

    The preliminary project of a diagnostic tool to measure the neutron emissivity profile for NET (Next European Torus) with an array of collimators is presented. With the help of a neutron transport code the maximum possible number of collimators, compatible with the crosstalk noise and the space available in the NET 2.2.B is determined within these constraints. An array of 17 collimators can be used, and some experimental results are simulated using a Monte Carlo code. These results are analyzed and an inversion procedure is used to obtain the emissivity profile and evaluate the total fusion power. The results show that the total fusion power can be measured within 10% for different emission profiles

  5. China action of "Cleanup Plan for Polychlorinated Biphenyls Burial Sites": emissions during excavation and thermal desorption of a capacitor-burial site.

    Science.gov (United States)

    Yang, Bing; Zhou, Lingli; Xue, Nandong; Li, Fasheng; Wu, Guanglong; Ding, Qiong; Yan, Yunzhong; Liu, Bo

    2013-10-01

    Scarce data are available so far on emissions in a given scenario for excavation and thermal desorption, a common practice, of soils contaminated with polychlorinated biphenyls (PCBs). As part of China action of "Cleanup Plan for PCBs Burial Sites", this study roughly estimated PCBs emissions in the scenario for a capacitor-burial site. The concentrations of total PCBs (22 congeners) in soils were in the range of 2.1-16,000μg/g with a mean of 2300μg/g, among the same order of magnitude as the highest values obtained in various PCBs-contaminated sites. Only six congeners belonging to Di-, Tri-, and Tetra-CBs were observed above limits of detection in air samples in the scenario, partially which can be estimated by the USEPA air emission model. Comparing concentrations and composition profiles of PCBs in the soil and air samples further indicated a leaked source of commercial PCBs formulations of trichlorobiphenyl (China PCB no. 1). The measures taken if any to mitigate the volatilization and movement of PCBs and to minimize worker exposure were discussed for improvements of the excavation practice. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Life cycle inventory analysis of regenerative thermal oxidation of air emissions from oriented strand board facilities in Minnesota - a perspective of global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, W.J. [Potlatch Corp., San Francisco, CA (United States)

    1997-12-31

    Life cycle inventory analysis has been applied to the prospective operation of regenerative thermal oxidation (RTO) technology at oriented strand board plants at Bemidji (Line 1) and Cook, Minnesota. The net system destruction of VOC`s and carbon monoxide, and at Cook a small quantity of particulate, has a very high environmental price in terms of energy and water use, global warming potential, sulfur and nitrogen oxide emissions, solids discharged to water, and solid waste deposited in landfills. The benefit of VOC destruction is identified as minor in terms of ground level ozone at best and possibly slightly detrimental. Recognition of environmental tradeoffs associated with proposed system changes is critical to sound decision-making. There are more conventional ways to address carbon monoxide emissions than combustion in RTO`s. In an environment in which global warming is a concern, fuel supplemental combustion for environmental control does not appear warranted. Consideration of non-combustion approaches to address air emission issues at the two operations is recommended. 1 ref., 5 tabs.

  7. THERMAL DIAGNOSTICS WITH THE ATMOSPHERIC IMAGING ASSEMBLY ON BOARD THE SOLAR DYNAMICS OBSERVATORY: A VALIDATED METHOD FOR DIFFERENTIAL EMISSION MEASURE INVERSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Mark C. M.; Boerner, P.; Schrijver, C. J.; Malanushenko, A. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street Bldg. 252, Palo Alto, CA 94304 (United States); Testa, P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chen, F.; Peter, H., E-mail: cheung@lmsal.com [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2015-07-10

    We present a new method for performing differential emission measure (DEM) inversions on narrow-band EUV images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. The method yields positive definite DEM solutions by solving a linear program. This method has been validated against a diverse set of thermal models of varying complexity and realism. These include (1) idealized Gaussian DEM distributions, (2) 3D models of NOAA Active Region 11158 comprising quasi-steady loop atmospheres in a nonlinear force-free field, and (3) thermodynamic models from a fully compressible, 3D MHD simulation of active region (AR) corona formation following magnetic flux emergence. We then present results from the application of the method to AIA observations of Active Region 11158, comparing the region's thermal structure on two successive solar rotations. Additionally, we show how the DEM inversion method can be adapted to simultaneously invert AIA and Hinode X-ray Telescope data, and how supplementing AIA data with the latter improves the inversion result. The speed of the method allows for routine production of DEM maps, thus facilitating science studies that require tracking of the thermal structure of the solar corona in time and space.

  8. Investigating the flow dynamics and chemistry of an expanding thermal plasma through CH(A-X) emission spectra

    NARCIS (Netherlands)

    Hansen, T. A. R.; Colsters, P. G. J.; M. C. M. van de Sanden,; Engeln, R.

    2011-01-01

    The gas flow in a linear plasma reactor and the plasma chemistry during hydrogenated amorphous carbon and graphite etching are investigated via time and spatially resolved measurements of the ion density and CH emission. A convolution of the ion and hydrocarbon density shows the importance of charge

  9. Performance evaluation of non-thermal plasma on particulate matter, ozone and CO2 correlation for diesel exhaust emission reduction

    DEFF Research Database (Denmark)

    Babaie, Meisam; Davari, Pooya; Talebizadeh, Poyan

    2015-01-01

    This study is seeking to investigate the effect of non-thermal plasma technology in the abatement of particulate matter (PM) from the actual diesel exhaust. Ozone (O3) strongly promotes PM oxidation, the main product of which is carbon dioxide (CO2). PM oxidation into the less harmful product (CO2...