Achieving accurate FTIR measurements on high performance bandpass filters

The sources of ordinate error in FTIR spectrometers are reviewed with reference to measuring small out-of-band features in the spectra of bandpass filters. Procedures for identifying instrumental artefacts are described. It is shown that features well below 0.01%T can be measured reliably

Study plan and preliminary results of the intervention in the Salmonella status of finishing herds by adding organic acids to the drinking water of finishers

Risk factor analysis of Salmonella infections in The Netherlands showed that feeding acidified or fermented byproducts to finishers gave a strong protection against Salmonella infections. This protective effect can be explained by bactericidal effect of the organic acids present in these feeds and the low pH (pH=4). In this study we investigated the hypothesis that the same result could be obtained by adding organic acids to the drinkingwater of finishers on farms that feed their finishers compound feed

Resulls of a longitudinal study of Salmonella enterica infections in 5 sero-positive and 5 sero-negative finishing swine herds in The Netherlands

In order to monitor the course of Salmonella-infections in finishing pig herds, repeated sampling of consecutive batches of finishing pigs is necessary. This study followed 5 sero-negative and 5 sero-positive herds during 7 sampling rounds with 3 months between samplings

Blood sampling at two slaughterhouses and serological screening of salmonella infections in swine using an indirect ELISA

The Animal Health Service in the Netherlands is currently investigating Salmonella infections in finishing pigs in the Netherlands. The investigations combine 2 projects: the SALINPORK-project, financed by the European Union, and a national project \u27Speerpunt Salmonella\u27, financed by the Dutch Ministry of Agriculture, Nature management and Fisheries and the Dutch Product Board for Livestock and Meat

The temperature-dependent spectral properties of filter substrate materials in the far-infrared (6-40 mu m)

This paper presents the experimental results on the low temperature absorption and dispersion properties for a variety of frequently used infrared filter substrate materials. Index of refraction (n) and transmission spectra are presented for a range of temperatures 300-50 K for the Group IV materials silicon (Si) and germanium (Ge), and Group II-VI materials zinc selenide (ZnSe), zinc sulphide (ZnS) and cadmium telluride (CdTe). (C) 2003 Elsevier B.V. All rights reserved

Physical effects in IR-coating materials

The effects of dispersion, angle of illumination and temperature in coated layers of infrared semiconductors (the IV-VI) and semiinsulators (the II-VI) are described. Examples are given of microcomputer calculations of these

Interference filters and coatings for mid-infrared astronomy (8-30µm)

The VISIR instrument for the European Southern Observatory (ESO) Very Large Telescope (VLT) is a thermal-infrared imager and spectrometer currently being developed by the French Service d'Astrophysique of CEA Saclay, and Dutch NFRA ASTRON Dwingeloo consortium. This cryogenic instrument will employ precision infrared bandpass filters in the N-( =7.5-14µm) and Q-( =16-28µm) band mid-IR atmospheric windows to study interstellar and circumstellar environments crucial for star and planetary formation theories. As the filters in these mid-IR wavelength ranges are of interest to many astronomical cryogenic instruments, a worldwide astronomical filter consortium was set up with participation from 12 differing institutes, each requiring instrument specific filter operating environments and optical metrology. This paper describes the design and fabrication methods used to manufacture these astronomical consortium filters, including the rationale for the selection of multilayer coating designs, temperature-dependant optical properties of the filter materials and FTIR spectral measurements showing the changes in passband and blocking performance on cooling to <50K. We also describe the development of a 7-14µm broadband antireflection coating deposited on Ge lenses and KRS-5 grisms for cryogenic operation at 40

Space exposure of infrared filters and materials on the NASA Long Duration Exposure Facility (LDEF)

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