Search results for "Calibration"
showing 10 items of 890 documents
Emission tomography with a large-hole collimator (CACAO): a possible new way to improve radionuclide imaging.
2002
This work aims to improve the quality of scintigraphy. It evaluates the use of a large-hole collimator, the Computer Aided Collimation Gamma Camera Project (CACAO), in SPECT. Acquisition data from the same object were simulated for CACAO and for a conventional collimator. Better signal-to-noise ratios were found for CACAO images, whatever the number of emitted photons. This work demonstrates that high-resolution images may be obtained with large-hole collimators. The combination of CACAO and pixilated detectors may further improve radionuclide imaging.
Studies of methods and tools for the really mixed visual coherence applied to the patrimony
2013
The work described in this report has as a target the mixed reality device ray-on, developed by the on-situ company. This device, dedicated to cultural heritage and specifically architectural heritage, is meant to be installed on-site and shows the user an uchronic view of its surroundings. As the chosen stance is to display photo-realistic images, two trails were followed: the improvement of the real-virtual merging by reproducing accurately the real lighting on the virtual objects, and the development of a real-time segmentation method which is resilient to lighting changes.Regarding lighting reproduction, an image-based rendering method is used in addition to a high dynamic range capture…
Temperature and emissivity separation from calibrated data of the Digital Airborne Imaging Spectrometer
2001
Abstract The Digital Airborne Imaging Spectrometer (DAIS), with six thermal infrared channels in the 8–14 μm window, was flown over the Barrax test site, Spain, in the framework of the DAIS Experiment in the summer of 1998. Atmospheric correction of the DAIS thermal channels was performed by means of local radiosonde measurements and a radiative transfer model. Ground measurements of temperature and emissivity for six selected spots (two bare soils, two water bodies, and two vegetated fields) were conducted with the objective of providing calibration and validation targets. Three targets were used for a linear ground calibration of the DAIS thermal channels. With the ground-calibrated image…
Wavefront holoscopy: application of digital in-line holography for the inspection of engraved marks in progressive addition lenses
2014
Progressive addition lenses (PALs) are engraved with permanent marks at standardized locations in order to guarantee correct centering and alignment throughout the manufacturing and mounting processes. Out of the production line, engraved marks provide useful information about the PAL as well as act as locator marks to re-ink again the removable marks. Even though those marks should be visible by simple visual inspection with the naked eye, engraving marks are often faint and weak, obscured by scratches, and partially occluded and difficult to recognize on tinted or antireflection-coated lenses. Here, we present an extremely simple optical device (named as wavefront holoscope) for visualiza…
Experimental calibration of flat jacks for in-situ testing of masonry
2018
Flat-jack testing method is one of the most commonly used techniques for the structural assessment of existing masonry structures. Single and double flat jacks are usually adopted to evaluate the acting normal stress, or the compressive behaviour of masonry material. Test procedures are codified by international standards (e.g., A.S.T.M D4729-87; C1196-04; C1197-04, R.I.L.E.M TC 177–MDT D.4; R.I.L.E.M. TC 177–MDT D.5), which provide the preliminary calibration of an experimental coefficient (km) and of the effective area (Aeff), which determination influences significantly the reliability of the test. This article presents the result of an experimental study on the calibration of flat jacks…
Calibration of in situ chlorophyll fluorometers for organic matter
2019
AbstractOrganic matter (OM) other than living phytoplankton is known to affect fluorometric in situ assessments of chlorophyll in lakes. For this reason, calibrating fluorometric measurements for OM error is important. In this study, chlorophyll (Chl) fluorescence was measured in situ in multiple Finnish lakes using two sondes equipped with Chl fluorometers (ex.470/em.650–700 nm). OM absorbance (A420) was measured from water samples, and one of the two sondes was also equipped with in situ fluorometer for OM (ex.350/em.430 nm). The sonde with Chl and OM fluorometers was also deployed continuously on an automated water quality monitoring station on Lake Konnevesi. For data from multiple lake…
Sequential injection analysis (SIA)-chemiluminescence determination of indomethacin using tris[(2,2'-bipyridyl)]ruthenium(III) as reagent and its app…
2006
Abstract Automated sequential injection (SIA) method for chemiluminescence (CL) determination of nonsteroidal anti-inflammatory drug indomethacin ( I ) was devised. The CL radiation was emitted in the reaction of I (dissolved in aqueous 50% v/v ethanol) with intermediate reagent tris(2,2′-bipyridyl)ruthenium(III) (Ru(bipy) 3 3+ ) in the presence of acetate. The Ru(bipy) 3 3+ was generated on-line in the SIA system by the oxidation of 0.5 mM tris(2,2′-bipyridyl)ruthenium(II) (Ru(bipy) 3 2+ ) with Ce(IV) ammonium sulphate in diluted sulphuric acid. The optimum sequence, concentrations, and aspirated volumes of reactant zones were: 15 mM Ce(IV) in 50 mM sulphuric acid 41 μL, 0.5 mM Ru(bipy) 3 …
Determination of phenolic antioxidants additives in industrial wastewater from polypropylene production using solid phase extraction with high-perfor…
2019
Abstract This paper describes a new method for the effective extraction of the residues of five synthetic phenolic antioxidants (AOs): Ditertbutylphenol (DTF), Irganox 1010, Irganox 1076, Ethanox 330 and Cyanox 1790, from industrial water produced during the polypropylene (PP) deodorization process. In the deordorization process, PP is stored in a column for an average time of four hours and exposed to nitrogen and water vapor to remove inflammable compounds which may generate atypical odors in the PP. The samples of interest were taken in the desorber, followed by cleansing and pre-concentration using modified styrene divinylbenzene polymer cartridges. Liquid chromatography was performed w…
Fourier transform infrared determination of CO 2 evolved from carbonate in carbonated apatites
2000
A quantitative method based on FTIR has been developed to determine carbonate in synthetic apatites. The method measures the evolved CO2 after reaction of 50 mg apatite with 2 mL of hydrochloric acid (0.5 M) in a reaction vessel, heated to 40 degrees C. The CO2 evolved was swept by a carrier of nitrogen to a laboratory-made infrared gas cell of 39 mm pathlength and 490 microL volume. The signals were recorded as a function of time and the areas of the chemigram peaks obtained from the measurements in the wavenumber range of 2,500-2,150 cm(-1), were interpolated using a calibration curve. The method can be used to study apatites with carbonate contents below 0.2% with a sampling frequency of…
Evaluation of two oxygen analyzers by computerized data acquisition and processing
1986
Monitoring of inspired oxygen concentration during anesthesia with nitrous oxide is becoming accepted as essential. This type of monitoring demands accurate monitors that respond rapidly. We evaluated two such devices for their response patterns to rapid changes in oxygen concentration, a galvanic or "fuel cell" unit and a polarographic device. Data were stored after analog-to-digital conversion. The response patterns to stepwise changes in nitrous oxide and oxygen mixtures were recorded at flow rates ranging from 2 to 10 L/min. Both units responded accurately to all changes in the absolute oxygen concentration; the polarographic unit was, on average, twice as fast. Responsiveness to nitrou…