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Applied Spectroscopy

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https://www.readbyqxmd.com/read/27899431/monitoring-process-water-quality-using-near-infrared-spectroscopy-and-partial-least-squares-regression-with-prediction-uncertainty-estimation
#1
Peter B Skou, Thilo A Berg, Stina D Aunsbjerg, Dorrit Thaysen, Morten A Rasmussen, Frans van den Berg
Reuse of process water in dairy ingredient production-and food processing in general-opens the possibility for sustainable water regimes. Membrane filtration processes are an attractive source of process-water recovery since the technology is already utilized in the dairy industry and its use is expected to grow considerably. At Arla Foods Ingredients (AFI), permeate from a reverse osmosis polisher filtration unit is sought to be reused as process water, replacing the intake of potable water. However, as for all dairy and food producers, the process-water quality must be monitored continuously to ensure food safety...
November 29, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27895234/ultraviolet-raman-wide-field-hyperspectral-imaging-spectrometer-for-standoff-trace-explosive-detection
#2
Kyle T Hufziger, Sergei V Bykov, Sanford A Asher
We constructed the first deep ultraviolet (UV) Raman standoff wide-field imaging spectrometer. Our novel deep UV imaging spectrometer utilizes a photonic crystal to select Raman spectral regions for detection. The photonic crystal is composed of highly charged, monodisperse 35.5 ± 2.9 nm silica nanoparticles that self-assemble in solution to produce a face centered cubic crystalline colloidal array that Bragg diffracts a narrow ∼1.0 nm full width at half-maximum (FWHM) UV spectral region. We utilize this photonic crystal to select and image two different spectral regions containing resonance Raman bands of pentaerythritol tetranitrate (PETN) and NH4NO3 (AN)...
November 28, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27888200/effect-of-principal-component-analysis-centering-and-scaling-on-classification-of-mycobacteria-from-raman-spectra
#3
Cynthia Hanson, Michael Sieverts, Elizabeth Vargis
Raman spectroscopy has been used for decades to detect and identify biological substances as it provides specific molecular information. Spectra collected from biological samples are often complex, requiring the aid of data truncation techniques such as principal component analysis (PCA) and multivariate classification methods. Classification results depend on the proper selection of principal components (PCs) and how PCA is performed (scaling and/or centering). There are also guidelines for choosing the optimal number of PCs such as a scree plot, Kaiser criterion, or cumulative percent variance...
November 25, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27881724/spectrum-reconstruction-of-a-spatially-modulated-fourier-transform-spectrometer-based-on-stepped-mirrors
#4
Jianhua Gao, Zhongzhu Liang, Jingqiu Liang, Weibiao Wang, Jinguang Lü, Yuxin Qin
Based on the basic configuration and interference principle of a static step-mirror-based Fourier transform spectrometer, an image segmentation method is proposed to obtain a one-dimensional interferogram. The direct current component of the interferogram is fit using the least squares (LS) method and is subsequently removed. An empirical-mode decomposition-method-based high-pass filter is constructed to denoise the spectrum and enhance the spectral resolution simultaneously. Several experiments were performed and the spectrum is reconstructed based on these methods...
November 23, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27876692/methods-for-broadband-spectral-analysis-intrinsic-fluorescence-temperature-sensing-as-an-example
#5
Weiwei Zhang, Guoyao Wang, Greg W Baxter, Stephen F Collins
A systematic study was performed on the temperature-dependent fluorescence of (Ba,Sr)2SiO4:Eu(2+) The barycenter and extended intensity ratio techniques were proposed to characterize the broadband fluorescence spectra. These techniques and other known methods (listed below) were employed and compared in the fluorescent temperature sensing experiment. Multiple sensing functions were obtained using the behaviors of: (1) the barycenter location of the emission band; (2) the emission bandwidth; and (3) the ratio of intensities at different wavelengths in the emission band, respectively...
November 22, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27876691/performance-assessment-of-a-plate-beam-splitter-for-deep-ultraviolet-raman-measurements-with-a-spatial-heterodyne-raman-spectrometer
#6
Nirmal Lamsal, S Michael Angel
In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter...
November 22, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27872219/shortwave-infrared-imaging-spectroscopy-for-analysis-of-ancient-paintings
#7
Taixia Wu, Guanghua Li, Zehua Yang, Hongming Zhang, Yong Lei, Nan Wang, Lifu Zhang
Spectral analysis is one of the main non-destructive techniques used to examine cultural relics. Hyperspectral imaging technology, especially on the shortwave infrared (SWIR) band, can clearly extract information from paintings, such as color, pigment composition, damage characteristics, and painting techniques. All of these characteristics have significant scientific and practical value in the study of ancient paintings and other relics and in their protection and restoration. In this study, an ancient painting, numbered Gu-6541, which had been found in the Forbidden City, served as a sample...
November 21, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27872218/wavelength-scanning-with-a-tilting-interference-filter-for-glow-discharge-elemental-imaging
#8
Andrew P Storey, Steven J Ray, Volker Hoffmann, Maxim Voronov, Carsten Engelhard, Wolfgang Buscher, Gary M Hieftje
Glow discharges have long been used for depth profiling and bulk analysis of solid samples. In addition, over the past decade, several methods of obtaining lateral surface elemental distributions have been introduced, each with its own strengths and weaknesses. Challenges for each of these techniques are acceptable optical throughput and added instrumental complexity. Here, these problems are addressed with a tilting-filter instrument. A pulsed glow discharge is coupled to an optical system comprising an adjustable-angle tilting filter, collimating and imaging lenses, and a gated, intensified charge-coupled device (CCD) camera, which together provide surface elemental mapping of solid samples...
November 21, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27872217/an-analysis-of-human-dorsal-hand-skin-texture-using-hyperspectral-imaging-technique-for-assessing-the-skin-aging-process
#9
Mihaela Antonina Calin, Sorin Viorel Parasca, Marian Romeo Calin, Emil Petrescu
Skin texture has become an important issue in recent research with applications in the cosmetic industry and medicine. In this paper, we analyzed the dependence of skin texture features on wavelength as well as on different parameters (age and gender) of human participants using grey-level co-occurrence matrix and hyperspectral imaging technique for a more accurate quantitative assessment of the aging process. A total of 42 healthy participants (men and women; age range, 20-70 years) was enrolled in this study...
November 21, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27864447/analysis-of-the-thermo-reflectivity-coefficient-influence-using-photothermal-pump-probe-techniques
#10
Vitor S Zanuto, Otávio A Capeloto, Marcelo Sandrini, Luis C Malacarne, Nelson G C Astrath, Stephen E Bialkowski
Recent improvements in the modeling of photo-induced thermo-optical-mechanical effects have broadened the application of photothermal techniques to a large class of solids and fluids. During laser excitation, changes in optical reflectivity due to temperature variation may affect the photothermal signal. In this study, the influence of the reflectivity change due to heating is analyzed for two pump-probe photothermal techniques, thermal lens and thermal mirror. A linear equation for the temperature dependence of the reflectivity is derived, and the solution is tested using optical properties of semi-transparent and opaque materials...
November 18, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27864446/simultaneous-imaging-and-spectroscopy-of-detonation-interaction-in-reactive-and-energetic-materials
#11
Stephanie Johnson, Michael Clemenson, Nick Glumac
A dual framing camera system was coupled with custom-designed ultrafast imaging spectrometer optics to yield simultaneous imaging and imaging spectroscopy of extremely short detonation interaction events in reactive materials. For short exposures of 100 ns or less, spectral resolutions of 2.4 Å are achievable, allowing for time-resolved identification of key intermediate species evolving from prompt reaction. Under some circumstances, emission can be fit to a local emission temperature, assuming the optically thin limit...
November 18, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27864445/comparison-of-fiber-optic-and-conduit-attenuated-total-reflection-atr-fourier-transform-infrared-ft-ir-setup-for-in-line-fermentation-monitoring
#12
Cosima Koch, Andreas E Posch, Christoph Herwig, Bernhard Lendl
The performance of a fiber optic and an optical conduit in-line attenuated total reflection mid-infrared (IR) probe during in situ monitoring of Penicillium chrysogenum fermentation were compared. The fiber optic probe was connected to a sealed, portable, Fourier transform infrared (FT-IR) process spectrometer via a plug-and-play interface. The optical conduit, on the other hand, was connected to a FT-IR process spectrometer via a knuckled probe with mirrors that had to be adjusted prior to each fermentation, which were purged with dry air...
November 18, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27864444/simultaneous-burst-imaging-of-dual-species-using-planar-laser-induced-fluorescence-at-50%C3%A2-khz-in-turbulent-premixed-flames
#13
Zheming Li, Joakim Rosell, Marcus Aldén, Mattias Richter
Spatially and temporally resolved measurements are of great importance in turbulent premixed flame studies, especially when investigating rapid processes such as when flame local extinction, re-ignition, or flashback occur in a reacting flow. Here, an experimental approach for simultaneously probing two different species at high frame rates (50 kHz) is presented by employing a multi-YAG laser system. The laser radiation at 355 nm generated by a multi-YAG laser system was split into two beam paths: one beam for exciting formaldehyde and the other for pumping an optical parametric oscillator (OPO)...
November 18, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27852875/does-nonlinear-modeling-play-a-role-in-plasmid-bioprocess-monitoring-using-fourier-transform-infrared-spectra
#14
Marta B Lopes, Cecília R C Calado, Mário A T Figueiredo, José M Bioucas-Dias
The monitoring of biopharmaceutical products using Fourier transform infrared (FT-IR) spectroscopy relies on calibration techniques involving the acquisition of spectra of bioprocess samples along the process. The most commonly used method for that purpose is partial least squares (PLS) regression, under the assumption that a linear model is valid. Despite being successful in the presence of small nonlinearities, linear methods may fail in the presence of strong nonlinearities. This paper studies the potential usefulness of nonlinear regression methods for predicting, from in situ near-infrared (NIR) and mid-infrared (MIR) spectra acquired in high-throughput mode, biomass and plasmid concentrations in Escherichia coli DH5-α cultures producing the plasmid model pVAX-LacZ...
November 16, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27852874/high-speed-scanning-for-the-quantitative-evaluation-of-glycogen-concentration-in-bioethanol-feedstock-synechocystis-sp-pcc6803-using-a-near-infrared-hyperspectral-imaging-system-with-a-new-near-infrared-spectral-camera
#15
Mika Ishigaki, Akihito Nakanishi, Tomohisa Hasunuma, Akihiko Kondo, Tetsu Morishima, Toshiaki Okuno, Yukihiro Ozaki
In the present study, the high-speed quantitative evaluation of glycogen concentration accumulated in bioethanol feedstock Synechocystis sp. PCC6803 was performed using a near-infrared (NIR) imaging system with a hyperspectral NIR spectral camera named Compovision. The NIR imaging system has a feature for high-speed and wide area monitoring and the two-dimensional scanning speed is almost 100 times faster than the general NIR imaging systems for the same pixel size. For the quantitative analysis of glycogen concentration, partial least squares regression (PLSR) and moving window PLSR (MWPLSR) were performed with the information of glycogen concentration measured by high performance liquid chromatography (HPLC) and the calibration curves for the concentration within the Synechocystis sp...
November 16, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27852873/angle-of-observation-influence-on-emission-signal-from-spatially-confined-laser-induced-plasmas
#16
Jiri Weiss, Luisa Maria Cabalín, J Javier Laserna
The present work focuses on the influence of the angle of observation on the emission signal from copper plasmas. Plasma plumes have been generated inside a home-made chamber consisting of two parallel glass windows spaced by 2.5 mm. This chamber allows observing plasma plumes from different collection angles throughout their perimeter, spanning from 20° to 80° with respect to the surface of the Cu target. In order to minimize the observed volume of the plasma, measurements were made from the closest distance possible through a metallic hollow tube...
November 16, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27852872/an-analytical-quantum-model-to-calculate-fluorescence-enhancement-of-a-molecule-in-vicinity-of-a-sub-10%C3%A2-nm-metal-nanoparticle
#17
Zahra Bagheri, Reza Massudi
An analytical quantum model is used to calculate electrical permittivity of a metal nanoparticle located in an adjacent molecule. Different parameters, such as radiative and non-radiative decay rates, quantum yield, electrical field enhancement factor, and fluorescence enhancement are calculated by such a model and they are compared with those obtained by using the classical Drude model. It is observed that using an analytical quantum model presents a higher enhancement factor, up to 30%, as compared to classical model for nanoparticles smaller than 10 nm...
November 16, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27821664/attenuated-total-reflection-atr-sampling-in-infrared-spectroscopy-of-heterogeneous-materials-requires-reproducible-pressure-control
#18
Zhenyu Lu, Brianna M Cassidy, Stephanie A DeJong, Raymond G Belliveau, Michael L Myrick, Stephen L Morgan
Attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy, in which the sample is pressed against an internal reflection element, is a popular technique for rapid IR spectral collection. However, depending on the accessory design, the pressure applied to the sample is not always well controlled. While collecting data from fabrics with heterogeneous coatings, we have observed systematic pressure-dependent changes in spectra that can be eliminated by more reproducible pressure control. We also described a pressure sensor adapted to work with an ATR tower to enable more precise control of pressure during ATR sampling...
November 7, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27815436/understanding-the-impact-of-chemical-variability-and-calibration-algorithms-on-prediction-of-solid-fraction-of-roller-compacted-ribbons-using-near-infrared-nir-spectroscopy
#19
Sameer Talwar, Cletus Nunes, Tim Stevens, Vishwas Nesarikar, Peter Timmins, Carl A Anderson, James K Drennen
The study is aimed at developing a near-infrared (NIR) method for predicting solid fraction (SF) of dry granulated ribbons manufactured with formulation variability. The study investigated the impact of unmodeled chemical variability and regression approaches on method performance. The study utilized an excipient-only formulation system. Calibration compacts were created with chemical and processing variability; followed by collection of NIR spectra. Partial least squares (PLS) and spectral slope algorithms were utilized to model compact SF...
November 4, 2016: Applied Spectroscopy
https://www.readbyqxmd.com/read/27815435/removing-cosmic-spikes-using-a-hyperspectral-upper-bound-spectrum-method
#20
Stephen M Anthony, Jerilyn A Timlin
Cosmic ray spikes are especially problematic for hyperspectral imaging because of the large number of spikes often present and their negative effects upon subsequent chemometric analysis. Fortunately, while the large number of spectra acquired in a hyperspectral imaging data set increases the probability and number of cosmic spikes observed, the multitude of spectra can also aid in the effective recognition and removal of the cosmic spikes. Zhang and Ben-Amotz were perhaps the first to leverage the additional spatial dimension of hyperspectral data matrices (DM)...
November 4, 2016: Applied Spectroscopy
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