Terahertz photometer to observe solar flares in continuum

Solar observations at sub-THz frequencies detected a new flare spectral component peaking in the THz range, simultaneously with the well known microwaves component, bringing challenging constraints for interpretation. Higher THz frequencies observations are needed to understand the nature of the mechanisms occurring in flares. A THz photometer system was developed to observe outside the terrestrial atmosphere on stratospheric balloons or satellites, or at exceptionally transparent ground stations. The telescope was designed to observe the whole solar disk detecting small relative changes in input temperature caused by flares at localized positions. A Golay cell detector is preceded by low-pass filters to suppress visible and near IR radiation, a band-pass filter, and a chopper. A prototype was assembled to demonstrate the new concept and the system performance. It can detect temperature variations smaller than 1 K for data sampled at a rate of 10/second, smoothed for intervals larger than 4 seconds. For a 76 mm aperture, this corresponds to small solar burst intensities at THz frequencies. A system with 3 and 7 THz photometers is being built for solar flare observations on board of stratospheric balloon missions.Comment: 11 pages, 8 figures, accepted by Journal of Infrared, Millimeter, and Terahertz Waves, 9 December 201

Efficacy of Composting Dead Poultry and Farms Wastes Infected with Avian Influenza Virus H5N1

Composting had proven to be an environmentally sound method for disposing dead birds. The composting process management and monitoring it´s thermal profile, moisture content, nutrient ingredients were determined and recorded during day 1 to 33. Isolation and characterization of H5N1 avian influenza virus (AIV) in freshly dead birds and their wastes before, during and after composting was carried out using RT-PCR based assay and sequence analysis. In composting the temperature was increased gradually from 40-60°C through days 5 to 15 then declined after day 15 till end composting. The dry conditions and increased temperature were important virus determinants. Failure of re-isolation of virus in consequence to increased temperature during composting was proven when tested at day 15, end composting and dryness period. AIV was characterized before composting in the birds trachea and compost mix. Positive isolation, characterization and sequence analysis of fragment 4 of H5 gene revealed clustering of the virus with those field strains circulating among chicken population in Egypt in 2011.Testing the composting mix at the day 15 and end of composting by RT-PCR assay revealed negative amplification confirming the efficacy of composting process for destroying AIV. Composting within the newly designed closed composter achieved unfavorable thermal and dryness conditions for H5N1 surviving with no isolation and characterization of AIV H5N1 from field dead birds and their wastes. The study proposes composting as a reliable, environmentally safe way to dispose poultry waste infected with H5N1 AIV

Metal mesh resonant filters or terahertz frequencies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The interest in terahertz photometric and imaging measurements has motivated the development of bandpass resonant filters to be coupled to multiple-pixel devices such as bolometer arrays. Resonant grids are relatively simple to fabricate, exhibiting high transmission at the central frequency, a narrow bandpass, and good rejection of the side frequencies of the spectrum. We have fabricated filters centered at different frequencies between 0.4 and 10 THz, using photolithography and electroforming techniques. Transmission measurements have shown center frequencies and bandwidths close to the design predictions. The performance of the filters was found not to be critically dependent on small physical deformations in the mesh, becoming more noticeable at higher frequencies (i.e., for smaller physical sizes). Wider bandwidths, needed to attain higher sensitivities in the continuum, were obtained by changing the design parameters for filters at 2 and 3THz. (c) 2008 Optical Society of America473260646069Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Argentina agency Consejo Nacional de Investigaciones Cientfficas y Tecnicas (CONICET)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

New telescopes for ground-based solar observations at submillimeter and mid-infrared

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