Reflectance Spectroscopy

Surface oxide films were grown on 99.99% copper and brass (copper-zinc alloy, Cu77Zn21Al2) in 0.1 mol L −1 borax solution at open circuit potential and were characterized using various experimental techniques. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. The thickness of the oxide layers on copper and brass was compared by chronopotentiometric curves and potentiodynamic reductions. The electrical properties of each oxide were analyzed by means of electrochemical impedance spectroscopy. Their influence on the oxygen reduction reaction was also investigated using voltammetry hydrodynamic tools such as the rotating disk electrode. The results show that the incorporation of Zn to Cu in brass changes the composition and the thickness of the surface film. The films grown on brass tend to be thicker but less resistive and Zn compounds incorporate to the film. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction is strongly inhibited on oxidized electrodes, particularly in the case of brass. The global number of exchanged electrons remains close to four and seems to be independent of the presence of surface oxides. .ar (S. Ceré). circuit potential and the relationship between the oxidized surface and the oxygen reduction reaction.

Knowledge of the observable properties of orbital debris is necessary to validate debris models for both the low Earth orbit (LEO) and the geosynchronous Earth orbit (GEO). Current methods determine the size and mass of orbital debris based on knowledge or assumption of the material type of the piece. Improvement in the knowledge of material is the goal of the

Visible (VIS) and near infrared (NIR) reflectance spectroscopy combined with multivariate data analysis were explored to predict fibre diameter in both clean and greasy Merino wool samples. Fifty clean and 400 greasy wool samples were analysed. Samples were scanned in a large cuvette using a NIRSystems 6500 monochromator instrument by reflectance in the VIS and NIR regions (400 to 2500 nm). Partial least square (PLS) regression was used to develop a number of calibration models between the spectral and reference data. Different mathematical treatments were used during model development. Cross validation was used to assess the performance and avoid overfitting of the models. The NIR calibration models gave a coefficient of determination in calibration (R2) > 0·90 for clean wool samples and a R2 < 0·50 for greasy wool samples. The values for the residual predictive value, RPD (ratio of standard deviation (s. d.) to the root mean square of the standard error of cross validation (...

In this paper a synthetic chronological survey of analytical applications of infrared spectroscopy for the characterization of the materials of polychrome works of art and archaeology is outlined. Various sampling methods are described and some relevant examples, drawn from the published cases, are presented. The various methods prove to be very effective in characterizing both the inorganic and organic constituents of a wide variety of artworks, giving an insight into the materials and techniques of execution of the artifacts and, in the case of infrared mapping techniques, pinpointing the analytical data within a precise layer of the stratigraphy of the cross-sectioned samples. Overall, the great analytical potential and wide field of application of this technique is fully brought to light. © 2001 Éditions scientifiques et médicales Elsevier SAS polychrome works of art / cross-sections / FTIR spectroscopy / FTIR microspectroscopy / fiber optics reflection spectroscopy 2. Infrared spectroscopy and art conservation 2.1. The past: going from dispersive to Fourier transform instruments In 1966 a paper by J.S. Olin entitled 'The use of Infrared Spectrophotometry in the examination of *Correspondence and reprints.

We present a novel technique for wide dynamic range optical investigations. It is based on a fast-gated silicon singlephoton avalanche diode (SPAD) in time-correlated single-photon counting (TCSPC) setup. The SPAD is gated-ON and OFF in 500 ps so as to detect photons only within a given time interval. This technique is particularly useful in applications where a large amount of unnecessary photons precede or follow the optical signal to be detected, such as in time-resolved near infrared (NIR) spectroscopy, optical mammography, and optical molecular imaging. In particular, in time-resolved reflectance spectroscopy, it is desirable to minimize the source-detector separation to improve system performance. This leads to the saturation of the detection electronics because of the huge amount of "early" photons back scattered by superficial layers. Our setup is able to reject these photons and detect only "late" photons from the sample, thus allowing an increase in the dynamic range and the injected power. We acquired diffusive curves of two phantoms with 95 ps time resolution and 10 7 dynamic range with a measurement time three orders of magnitude shorter than what is currently possible with a standard TCPSC setup.

The paper presents the application of non−modulation reflectance method for composition profiling of epitaxial Al x Ga 1-x As/GaAs structures. This non−destructive method is based on spectral measurements and theoretical reflectance spectrum matching. This is a very accurate and sensitive method of determining the Al composition in Al x Ga 1-x As layers and structures with resolution down to 1 nm. In this work, the authors describe theoretic principles of this method and present ex− perimental results of characterization of different AlGaAs structures to prove the potential of the worked out method.

1] Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis. We describe a new system that is effective at material identification and mapping: a set of algorithms within an expert system decision-making framework that we call Tetracorder. The expertise in the system has been derived from scientific knowledge of spectral identification. The expert system rules are implemented in a decision tree where multiple algorithms are applied to spectral analysis, additional expert rules and algorithms can be applied based on initial results, and more decisions are made until spectral analysis is complete. Because certain spectral features are indicative of specific chemical bonds in materials, the system can accurately identify and map those materials. In this paper we describe the framework of the decision making process used for spectral identification, describe specific spectral feature analysis algorithms, and give examples of what analyses and types of maps are possible with imaging spectroscopy data. We also present the expert system rules that describe which diagnostic spectral features are used in the decision making process for a set of spectra of minerals and other common materials. We demonstrate the applications of Tetracorder to identify and map surface minerals, to detect sources of acid rock drainage, and to map vegetation species, ice, melting snow, water, and water pollution, all with one set of expert system rules. Mineral mapping can aid in geologic mapping and fault detection and can provide a better understanding of weathering, mineralization, hydrothermal alteration, and other geologic processes. Environmental site assessment, such as mapping source areas of acid mine drainage, has resulted in the acceleration of site cleanup, saving millions of dollars and years in cleanup time. Imaging spectroscopy data and Tetracorder analysis can be used to study both terrestrial and planetary science problems. Imaging spectroscopy can be used to probe planetary systems, including their atmospheres, oceans, and land surfaces. Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems,

To cite this Article Pandit, Caaminee M. , Filippelli, Gabriel M. and Li, Lin(2010) 'Estimation of heavy-metal contamination in soil using reflectance spectroscopy and partial least-squares regression', International Journal of Remote Sensing, 31: 15, 4111 -4123 To link to this Article:

Thin films of hafnium oxide (HfO 2 ) have been grown by high pressure reactive sputtering on transparent quartz substrates (UV-grade silica) and silicon wafers. Deposition conditions were adjusted to obtain polycrystalline as well as amorphous films. Optical properties of the films deposited on the silica substrates were investigated by transmittance and reflectance spectroscopy in the ultraviolet, visible and near infrared range. A numerical analysis method that takes into account the different surface roughness of the polycrystalline and amorphous films was applied to calculate the optical constants (refractive index and absorption coefficient). Amorphous films were found to have a higher refractive index and a lower transparency than polycrystalline films. This is attributed to a higher density of the amorphous samples, which was confirmed by atomic density measurements performed by heavy-ion elastic recoil detection analysis. The absorption coefficient gave an excellent fit to the Tauc law (indirect gap), which allowed a band gap value of 5.54 eV to be obtained. The structure of the films (amorphous or polycrystalline) was found to have no significant influence on the nature of the band gap. The Tauc plots also give information about the structure of the films, because the slope of the plot (the Tauc parameter) is related to the degree of order in the bond network. The amorphous samples had a larger value of the Tauc parameter, i.e. more order than the polycrystalline samples. This is indicative of a uniform bond network with percolation of the bond chains, in contrast to the randomly oriented polycrystalline grains separated by grain boundaries.

Reflectance spectroscopy has been used to identify several deposit types. However, applications concerning lithium (Li)-pegmatites are still scarce. Reflectance spectroscopic studies complemented by microscopic and geochemical studies were employed in the Fregeneda–Almendra (Spain–Portugal) pegmatite field to analyze the spectral behavior of Li-minerals and field lithologies. The spectral similarity of the target class (Li-pegmatites) with other elements was also evaluated. Lepidolite was discriminated from other white micas and the remaining Li-minerals. No diagnostic feature of petalite and spodumene was identified, since their spectral curves are dominated by clays. Their presence was corroborated (by complementary techniques) in petalite relics and completely replaced crystals, although the clay-related absorption depths decrease with Li content. This implies that clays can be used as pathfinders only in areas where argillic alteration is not prevalent. All sampled lithologies p...

Geothermal investors need to be confident with the methods and results of exploration programs. Also cutting the upfront cost of geothermal exploration will further encourage investors to consider investment in this emerging clean energy field. Hence, it is of paramount importance to improve prospecting techniques in order to explore where economic concentrations of geothermal energy are to be expected.  The current study evaluates different approaches for downscaling thermal data from remote sensing images together with factors in surface and subsurface environment. The paper discusses case studies, the challenge and the way forward for geothermal prospecting as well as practical solutions to discrepancy that faces the mapping and documentation of spatial geothermal anomalies.  It also discusses main criteria that should be considered while prospecting for geothermal energy.

In the present study, titanium dioxide nanoparticles were synthesized by sol-gel method, from various precursors in some solvents under different synthesis conditions such as solvent percent, water percent, reflux temperature, reflux time, sol drying method and calcination temperature. Structure, size, band gap and specific surface area of nanoparticles were determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis reflectance spectroscopy (DRS) and BET analysis methods. The photocatalytic activity of TiO 2 was evaluated in the photodegradation of C.I. Acid Red 27 as a model contaminant from textile industry under UV-C light irradiation. Results indicate that structure and photocatalytic activities are functions of precursor type, solvent type and other synthesis conditions. TiO 2 nanoparticles synthesized in the presence of methanol as solvent and titanium (IV) isopropoxide as precursor under 3 h reflux at 80°C with sol thermal drying and calcination temperature of 450°C indicate high photocatalytic activity in comparison with TiO 2 -P25 (Degussa Co.).

The non-destructive application of reflectance spectroscopy within chert provenance studies is evaluated and the implications of archaeological source determination of chert artifacts are discussed. The combined use of Visible Near-infrared (VNIR) and Fourier Transform Infrared (FTIR) reflectance spectroscopy demonstrate the accurate, fast and relatively low cost potential for the characterization of geologic deposits of chert and the identification of source for chert archaeological materials. Reflectance spectroscopy gathers data on the trace and minor mineral components within a sample as identified by subtle absorption peaks and slope changes. The variable range of spectral features per sample, per deposit, per geologic formation is potentially diagnostic for a geographically isolated deposit of chert. A chert sample database consisting of 2,430 samples from the Midwestern and Southeastern United States is utilized to illustrate the potential application of reflectance spectrosc...

Vincent van Gogh's still lifes Irises and Roses were investigated to shed light onto the degree to which the paintings had changed, both individually and in relation to each other since they were painted, particularly in regard to the fading of the red lakes. Non-invasive techniques, including macroscopic X-ray fluorescence mapping, reflectance imaging spectroscopy, and X-radiography, were combined with microanalytical techniques in a select number of samples. The in-depth microchemical analysis was necessary to overcome the complications that arise when evaluating by non-invasive methods alone the compositions of passages with complex layering and mixing of paints. The results obtained by these two approaches were complemented by color measurements performed on paint cross-sections and on protected edges, and with historical information provided by the artist's own descriptions, early reviews and reproductions, and the data was used to carry out digital color simulations that provided, to a certain extent, a visualization of how the paintings may have originally appeared.

Visual source analysis of particular variants of chert is problematic.  Chert source data derived from macroscopic identification is sometimes inaccurate leading to flawed behavioral models.  Provenance researchers should first assume a local source prior to labeling a material as ‘exotic’.  The study characterizes visually similar variants of Ste. Genevieve and Upper St. Louis chert from central Kentucky and Tennessee.  Results indicate that excellent deposits of both varieties exist throughout the study area far south from the well-known Wyandotte sources of Harrison County, Indiana.  Additionally, the application of reflectance spectroscopy is shown to be a promising technique in chert source characterization.

A composition-dependent empirical interpolation formula for the refractive index of AlGaInAs epilayers lattice matched to InP substrate has been determined by using a reflection spectroscopy technique. The 2 μm thick (AlGaIn)As layers have been grown by MBE as well as MOVPE and were characterized by x-ray diffractometry and photoluminescence measurements. The measured data from these etalon structures were fitted by using a Sellmeier equation (single oscillator model) to retrieve the refraction index for wavelengths between 2.5 and 1 μm. The resulting accurate expression will be very useful for designing optoelectronic devices like VCSELs.

Site specific, in situ techniques such as X-ray fluorescence (XRF) and Raman spectroscopy are commonly used to identify pigments on illuminated manuscripts. With both techniques, spectra are usually acquired on visually identified sites thought to be representative of the pigments and mixtures used for the illumination. Such visual inspection may not always ensure an adequate representation of the pigment diversity. Here we report on the application of multispectral (MSI) visible/infrared reflectance and luminescence imaging spectroscopy, along with fiber optics reflectance spectroscopy (FORS) to help determine and map the primary pigments in a late 14th century miniature on vellum, attributed to Niccolo da Bologna and representing the birth of John the Baptist. XRF analyses of visually selected sites found elements consistent with azurite, ultramarine, vermillion, lead white, "mosaic gold" and yellow earth pigments. Visible/infrared FORS analyses confirmed these assignments and showed evidence for the use of organic dyes. The spectral analysis of the MSI-reflectance images gave distribution maps for these pigments (i.e., regions of azurite, ultramarine, vermillion) along with some indication of pigment layering not identified visually. The luminescence image gave a probable map of the organic dye(s). Images acquired in the near- and shortwave-infrared (NIR and SWIR, 750 to 2400 nm) revealed preparatory sketches and illumination techniques. These results show, like those of a prior study carried out on another 14th century Italian miniature, that the combination of low light multi-spectral imaging spectroscopy with FORS provides improved in situ mapping and identification of pigments on illuminated manuscripts.

La investigación, nace a partir de la duda que genera el entender un gran numero de técnicas y herramientas que estan siendo empleadas acutalmente, y la manera en que se aplican al campo de los bienes culturales muebles,  enfocadas a la caracterización de la superficie a cualquier escala métrica.
El enfoque a la técnica de  Imágenes por transformación de reflectancia (Reflectance Transformation imaging)RTI se genera a partir de la iniciativa de la Maestra Alejandra Nieto (UASLP-Facultad del Hábitat), y su invitación a poner en valor práctico,  experimental y  evaluativo, dicha técnica. Con el objeto de generar un documento que ofresca datos precisos de empleo y a partir de eso tener una iniciativa del equipamiento correcto así como una autogestión a la divulgación de la técnica.
Dado que RTI una herramienta relativamente nueva. (Malzbender T., 2000) (Malzbender T., 2000) dentro del sistema común geopolítco americano, y más especifico en México, su complejidad  de aplicación, acceso y costos  suelen impedir su uso común en los talleres de la Facultad del Hábitat. Por lo cual el acercamiento teórico y práctico potencia la posibilidad de plantear un uso frecuente de la misma al igual que una adquisición de equipo inmediata.

La primera parte del documento menciona a manera de introducción todas las técnicas y herramientas empleadas actualmente por los laboratorios y espacios especizalizados en patrimono cultural. Los  parametros que delimitan su inclusión son; No destructivas, especificas de patrimonio mueble y lo menos invasivas en casos especiales.
La conclusión como criterio de pertinencia  se genera a través de la investigación y  el acercamiento a otras técnicas como un marco contextual,  al igual que  por una evaluación cualitativa y cuantitativa de especificamente RTI, bajo criterio de práctica y evaluación.(CRBCM) .
Cabe mencionar que se anexa un glosario con terminos y conceptos a base de guia, para despejar dudas de terminologías, conceptos o traducciones que limiten la información.

In this paper a synthetic chronological survey of analytical applications of infrared spectroscopy for the characterization of the materials of polychrome works of art and archaeology is outlined. Various sampling methods are described and some relevant examples, drawn from the published cases, are presented. The various methods prove to be very effective in characterizing both the inorganic and organic constituents of a wide variety of artworks, giving an insight into the materials and techniques of execution of the artifacts and, in the case of infrared mapping techniques, pinpointing the analytical data within a precise layer of the stratigraphy of the cross-sectioned samples. Overall, the great analytical potential and wide field of application of this technique is fully brought to light. © 2001 Éditions scientifiques et médicales Elsevier SAS polychrome works of art / cross-sections / FTIR spectroscopy / FTIR microspectroscopy / fiber optics reflection spectroscopy 2. Infrared spectroscopy and art conservation 2.1. The past: going from dispersive to Fourier transform instruments In 1966 a paper by J.S. Olin entitled 'The use of Infrared Spectrophotometry in the examination of *Correspondence and reprints.

Autorizzazione Tribunale di Milano n. 321 del 17-10-74 I testi presentati a «Rassegna di Studi e di Notizie» per la pubblicazione vengono valutati in forma anonima da studiosi competenti per la specifica materia (peer review). I membri del Comitato scientifico, costituito ad hoc, esercitano quindi la loro attività di supporto scientifico senza essere indicati in modo esplicito. Il Comitato dei revisori scientifici viene di volta in volta integrato con ulteriori valutatori quando utile o necessario per la revisione di contributi di argomento o taglio particolare. La direzione della rivista conserva, sotto garanzia di assoluta riservatezza, la documentazione relativa al processo di valutazione.

The non-destructive application of reflectance spectroscopy within chert provenance studies is evaluated and the implications of archaeological source determination of chert artifacts are
discussed. The combined use of Visible Near-infrared (VNIR) and Fourier Transform Infrared (FTIR) reflectance spectroscopy demonstrate the accurate, fast and relatively low cost for the
characterization of geological deposits of chert and the potential identification of source for chert archaeological materials. Reflectance spectroscopy gathers data on the trace and minor mineral components within a sample as identified by subtle absorption peaks and slope changes. The variable range of spectral features per sample, per deposit, per geological formation is potentially diagnostic for a geographically isolated deposit of chert. A chert sample database consisting of
2430 samples from the Midwestern and Southeastern United States is utilized to illustrate the accuracy of reflectance spectroscopy at characterizing chert deposits for archaeological use.

Paintings are composed of superimposed layers of inorganic and organic materials (pigments and binders). Knowledge of the stratigraphic sequence of these heterogeneous layers is fundamental for understanding the artist’s painting technique and for conservation issues. In this study, micro-IR mapping experiments in reflection mode have been carried out on cross-sections taken from simulations of ancient easel paintings. The objective was to locate both organic binders and inorganic pigments. Chemical maps have been re-constructed using the common approach based on the integration of specific infrared bands. However, owing to the complexity of painting materials, this approach is not always applicable when dealing with broad and superimposed spectral features and with reststrahlen or derivative-like bands resulting from acquisition in reflection mode. To overcome these limitations, principal-component analysis has been successfully used for the re-construction of the image, extracting the relevant information from the complex full spectral data sets and obtaining reliable chemical distributions of the stratigraphy materials. Different pigment–binder combinations have been evaluated in order to understand limitations and strengths of the approach. Finally, the method has been applied for stratigraphic characterization of a cross-section from a 17th century wooden sculpture identifying both the original paint layer and the several overpaintings constituting the complex stratigraphy. Figure a) OM image of an easel painting cross-section with the grid indicating the IR mapped area; b) t1 vs. t2 score plot including the color bar referred to the score values along each components; c) t2-score map; d) p1 and p2 profiles from PCA (labels: Gy-gypsum, L-lipid, I-amide I, II-amide II, U-ultramarine blue)

In this paper, a multi-technique in-situ non-invasive approach has been followed for the study of the materials used for a painting by Pierre-Auguste Renoir, “A woman at her toilette”. The study was carried out using five portable spectroscopic techniques, namely X-ray fluorescence, mid-infrared reflectance spectroscopy, near infrared reflectance spectroscopy, and UV-Vis spectroscopy in absorption and emission. The painting was selected as a case study because it was examined in advance of the current investigation using conventional micro-sampling techniques. This provided the opportunity to evaluate potential and limitations of the non-invasive approach to the complex case of the modern painting.

Reflection imaging spectroscopy is a useful technique to remotely identify and map minerals and vegetation. Here we report on the mapping and identification of artists' materials in paintings using this method. Visible and infrared image cubes of Picasso's Harlequin Musician are collected using two hyperspectral cameras and combined into a single cube having 260 bands (441 to 1680 nm) and processed using convex geometry algorithms. The resulting 18 spectral end members are identified by comparison with library spectra, fitting by nonlinear mixing, and using results from luminescence imaging spectroscopy. The results are compared with those from X-ray fluorescence spectrometry, polarized light microscopy, and scanning electron microscopy-energy dispersive spectrometry (SEM/EDS). This work shows the potential of reflection imaging spectroscopy, in particular if the shortwave infrared region is included along with information from luminescence imaging spectroscopy.

Hyperspectral visible near infrared reflectance spectroscopy (VNIRRS) and geostatistical methods are considered for precision soil mapping. This study evaluated whether VNIR or geostatistics, or their combined use, could provide efficient approaches for assessing the soil spatially and associated reductions in sample size using soil samples from a 32 ha area (800 × 400 m) in northern Turkey. Soil variables considered were CaCO3, organic matter, clay, sand and silt contents, pH, electrical conductivity, cation exchange capacity (CEC) and exchangeable cations (Ca, Mg, Na and K). Cross-validation was used to compare the two approaches using all grid data (n = 512), systematic selections of 13, 25 and 50% of the data and random selections of 13 and 25% for calibration; the remaining data were used for validation. Partial least squares regression (PLSR) analysis was used for calibrating soil properties from first derivative VNIR reflectance spectra (VNIRRS), whereas ordinary-, co- and regression-kriging were used for spatial prediction. The VNIRRS-PLSR method provided better prediction results than ordinary kriging for soil organic matter, clay and sand contents, (R 2 values of 0.56–0.73, 0.79–0.85, 0.65–0.79, respectively) and smaller root mean squared errors of prediction (values of 2.7–4.1, 37.4–43, 46.9–61, respectively). The EC, pH, Na, K and silt content were predicted poorly by both approaches because either the variables showed little variation or the data were not spatially correlated. Overall, the prediction accuracy of VNIRRS-PLSR was not affected by sample size as much as it was for ordinary kriging. Cokriging (COK) and regression kriging (RK) were applied to a combination of values predicted by VNIR reflectance spectroscopy and measured in the laboratory to improve the accuracy of prediction of the soil properties. The results showed that both COK and RK with VNIRRS estimates improved the predictions of soil variables compared to VNIRRS and OK. The combined use of VNIRRS and multivariate geostatistics results in better spatial prediction of soil properties and enables a reduction in sampling and laboratory analyses.

The project for the scientific analysis of Kaitag textiles – the
results of which are reported here with special focus on the
identification of the dyes – was promoted by the MATAM
association (Museum of Ancient Textile Art Milan) and carried
out by the Universities of Bergamo and Milan as the logical
continuance and updating of the important analytical project
conducted by Harald Bohmer and Recep Karadag almost
two decades ago1.
On the one hand, our project was inspired by the need to
determine, for a given artefact, the execution technique and
the materials used, not only for the sake of knowledge but
also for practical conservation purposes. At the same time,
from a methodological point of view, the intent was to use not
only the most frequently-applied analytical procedures, but
also non-invasive techniques suitable for in-situ analysis, and
such as to safeguard the integrity of the objects examined.
The most representative tints were selected for analysis in
order to obtain a wider knowledge of the dyes, and their
combinations, used over the centuries in Daghestan. In addition,
special attention was paid to those tints for which the
identification of the dyes is notoriously more difficult (especially
yellow) and to cases of suspected alteration of the dye
or evident damage to the thread.
A total of 23 Kaitag textiles were examined, dating from the
17th to the 18th century. A preliminary imaging campaign
was performed on all of them using infra-red (IR) reflectography
and ultraviolet (UV) fluorescence, in order to better understand
the technique used and to highlight any later integrations
of the textiles (which, however, were detected in only
a few cases). In addition, the presence of a black-ink underdrawing
was observed using reflectography. Thereafter, the
dyes were analysed using non-invasive techniques such as
visible reflectance spectroscopy (vis-RS) on 250 measurement
points, and Fourier-transform infrared spectroscopy
(FTIR) on 30 measurement points. Colorimetric data were
acquired on each of the points studied during the vis-RS
measurements. Also, energy dispersive X-ray fluorescence
(ED-XRF) was performed on two of the fabrics using a portable
handheld spectrometer. Extracts from 65 tiny portions of
dyed thread were then examined by high-performance liquid
chromatography (HPLC) and surface-enhanced Raman
spectroscopy (SERS); other threads were analysed without
extraction by energy-dispersive X-ray analysis coupled with
scanning electron microscopy (SEM-EDS), attenuated total
reflection (ATR) FTIR spectroscopy and Fourier-transform
Raman (FT-Raman) spectroscopy.
The dyes identified, which were all of natural origin, include:
madder for red, indigo for dark and light blue, weld for yellow
(the substance or substances used to obtain the more intense
yellow hues, however, remains unidentified), weld (or sometimes
a different yellow dye) and indigo for green, tannins
mordanted with iron for dark brown, again tannins, sometimes
with the addition of indigo, for black. A high content of
iron is often accompanied by corrosion of the dyed thread.
Finally, the ink used for the underlying drawing was carefully
examined and identified as carbon ink.

This study explores the evolution of the manufacturing process of artificial arsenic sulfide pigments in Edo-period Japan through the analysis of three impressions of the same print dated from the 1830s and attributed to Katsushika Hokusai (1760-1849), and one from 1852 and attributed to Utagawa Kunisada (1786-1865). Colorants in the yellow and green areas of the four prints were investigated by means of non-invasive and microanalytical techniques such as optical microscopy, fiber optic reflectance spectroscopy and Raman spectroscopy. While the pigments in the green and yellow areas are similar throughout the set of prints-Prussian blue, indigo (for the Hokusai prints) and orpiment were identified-optical microscopy and Raman spectroscopy highlighted some variations in the orpiment used in the green areas of the prints. Two of the Hokusai prints present bright yellow particles of larger size and lamellar morphology, identified by Raman spectroscopy as natural orpiment. The third print presents an admixture of bright yellow natural orpiment particles with a smaller number of orange-yellow particles shown by Raman to be partially amorphous arsenic sulfide. Small bright yellow particles identified as fully amorphous arsenic sulfide pigments by Raman were found throughout the green areas of the Kunisada print. Although supported by Japanese historical sources, local production of artificial arsenic sulfide in the early nineteenth century was not previously documented. The simultaneous presence of both crystalline and amorphous domains in a single pigment particle in some of the Hokusai prints suggests that natural orpiment was used as primary source of arsenic for the production of a low grade artificial pigment. The pigment found in the Kunisada print, by contrast, was obtained from arsenic oxide (or arsenolite) and sulfur though a dry-process synthesis, as shown by the sulfur excess, signs of heat treatments and fully amorphous nature of the pigment. These findings set the earliest dates for both the ore sublimation process and the arsenolite dry process, and are of foremost importance to understand the evolution of the amorphous arsenic sulfide production in Edo-period Japan and its introduction in the palette of Japanese woodblock prints.

In this study, a quality by design approach was applied to the design and scale-up of a batch mixing process. Mixtures of acetaminophen and lactose were sampled at different mixing times using a groove sampler. Samples were subsequently analyzed using NIR reflection spectroscopy. The effects of four processing parameters on the empirical mixing rate in a bin blender were examined. Blender rotation rate (two levels), powder fill level (two levels), powder cohesion (two levels), and blender size (three levels) represent the four parameters studied. Blender geometry and blender loading method were treated as constant parameters. Statistical analysis was used to assess the impact each parameter had on the mixing rate. Blender size (p=0.02), powder cohesion (p=0.05), and rotation rate (p=0.07) all significantly affected the mixing rate. The least significant parameter was the vessel fill level (p=0.18), indicating mixing performance is not strongly affected by fill level, given the range studied.

Existing Mississippian chert resource selection models are largely centered upon well documented quarry sites. As a result, chert source is macroscopically assigned to these static locations on the landscape. Provenance results for a sample of Mississippian sword-form bifaces suggests that material selection decisions are potentially diverse and are not solely confined to material from major prehistoric quarry sites. Provenance data for a sample of Mississippian chert 'swords' highlights a variety of sources beyond the Dover Quarry Complex possibly indicating inter-regional relationships between Middle Mississippi and South Appalachian polities. Results signify the importance of material selection within cultural meaning.

The electrochemically synthesized conducting copolymer consisting of 3-octylthiophene and biphenyl units has been characterized by in situ resonance Raman spectroscopy, UV-visible spectroscopy, in situ FTIR attenuated total reflectance spectroscopy and cyclic voltammetry. The structure of the formed material is compared with the two homopolymers: poly(3-octylthiophene) or poly(paraphenylene). The results show that the thiophene segments are longer than the phenylene segments in the poly(thienyl biphenyl) film formed. During electrochemical doping the Raman spectra indicate changes in the polymer backbone that can be assigned to transformation of the neutral form into the charged form. # : S 0 3 7 9 -6 7 7 9 ( 0 2 ) 0 0 0 7 5 -9

Carbon-supported Pt-based nanosized electrocatalysts can be synthesized for methanol and ethanol electrooxidation. The electrocatalytic activity of Pt can be greatly enhanced by using Pt-Ru/C for methanol oxidation or Pt-Sn/C for ethanol oxidation. In situ IR reflectance spectroscopy is a convenient tool to better understand the importance of the different adsorption steps involved in the mechanisms of electrooxidation. With Pt/C, it appears clearly that linearly adsorbed CO is the poisoning species formed during methanol and ethanol oxidation. In the case of methanol, even with Pt-Ru/C (the most active catalyst), adsorbed CO is also a reactive intermediate. The enhancement of activity observed in such a case is due to the possibility to activate water at lower potentials in the presence of Ru. With Pt-Sn/C, the mechanism of the electrooxidation of ethanol is strongly modified. If at low potentials, poisoning with adsorbed CO still exists (as with Pt/C), the oxidation of ethanol at potentials greater than 0.4 V versus RHE occurs through an adsorbed acetyl species which can lead to the formation of acetaldehyde and acetic acid as final products in addition to carbon dioxide.

A method for the simultaneous spectrophotometric determination of leather dyes based on their reflectance spectrum in the visible region and the use of partial least-squares regression (PLSR) is proposed. Calibration was done by using absorption, first-and second-derivative spectra for five sets of 29 different mixtures of Sellaset H dyes over the wavelength range 400-900 nm. The proposed multivariate calibration method allowed us to develop a model adjusted to the dye concentrations in the mixtures used at the calibration stage. The method was validated with five test sets consisting of eight samples each.

Two quantification methods for light reflectance spectroscopy (LRS) were developed and validated to determine absolute and relative values of hemodynamic parameters and light scattering, followed by a specific application using in vivo animal experiments. A single-channel LRS system consisted of a light source, CCD-array detector, and a computer along with a bifurcated, 2-mm-diameter optical probe; this system was utilized to perform laboratory tissue phantoms for validation of the algorithms. In the animal study, a multichannel, multisite approach was used to measure several reflectance spectra from rat brain and spinal cord on both the ipsi-lateral and contra-lateral sides, using thin 800-μm-diameter optic probes. The neurohemodynamic changes were induced by 10-V electrical stimulation in rat hind paw. The LRS data of the animals were analyzed using both absolute and relative methods. The results show that the relative method is computation-efficient and offers a quick estimation of changes in oxy-hemoglobin concentration for real-time monitoring. The absolute quantification method, on the other hand, provides us with an accurate computational tool to calculate absolute values of oxy-, deoxy-, total hemoglobin concentrations, and light scattering coefficients. We also observe that the hemodynamic responses in rat spinal cord were delayed with a few seconds and have an overall broader full width at half maximum, as compared to those from rat somatosensory cortex. LRS as a measurement system provides a robust method for studying local hemodynamic changes and a potential technique to investigate hemo-neural mechanisms in pain processing.

Using a combination of density functional theory (DFT) calculations and experiments, we determine the structural and electronic properties of cerium orthophosphate (CePO 4), a promising proton-conducting electrolyte for fuel cell applications. To better account for strongly-localized Ce 4f electrons, we use a DFT + U approach, where the exchange-correlation functional is augmented with an adjustable effective Hubbard-like parameter U. We find that the calculated structural properties are in good agreement with x-ray diffraction measurements, largely independent of the value of U used. However, the electronic structure is much more sensitive to U, and values of U = 2.5-3 eV for Ce 4f states provide excellent agreement between the calculated density of states and measured photoemission spectra near the valence-band edge, validating the efficacy of a DFT + U-based approach for this system. With a judicious choice of U determined from photoemission experiments, this work provides a natural starting point for future studies of charge transport and charged defect formation and migration in this important class of compounds.

The production process of an active pharmaceutical ingredient (API) by fermentation in an industrial environment was analysed using process analytical technologies.The Food and Drug Administration's (FDA) process analytical technology (PAT) initiative is intended to be a collaborative effort with industry to promote the integration of new manufacturing technologies into pharmaceutical production [FDA. 2003 bPAT-A Framework for Innovative Pharmaceutical Manufacturing and Quality Assurance (Draft Guideline).Q https://www.fda.gov/cder/OPS/ PAT.htm]. Within the PAT framework the aim is to design, develop and operate processes consistently to ensure a predefined quality at the end of the manufacturing process. Several case-studies are discussed in which combining chemometrics methods with NIR spectra from samples in different process stages leads to increased process understanding and process control of an API production process. The ab-initio prediction of the expected final titter of an antibiotic fermentation was obtained with raw materials and inoculum quality quantification. NIR reflectance spectroscopy was applied to monitor at-line different quality variables for process samples taken from the fermentation stage of the whole process. Finally, the at-line use of NIR transmittance spectroscopy in one of the API downstream purification steps is described. In this paper the use of PAT as a tool to operate an important shift in quality control efforts is illustrated, showing that quality should not be tested only on final products but in-process to obtain increased quality assurance of final products. D

Purpose: Carbon-loaded thermoluminescent dosimeters (TLDs) are designed for surface/skin dose measurements. Following 4 years in clinical use at the Mater Hospital, the accuracy and clinical usefulness of the carbon-loaded TLDs was assessed. Methods and Materials: Teflon-based carbon-loaded lithium fluoride (LiF) disks with a diameter of 13 mm were used in the present study. The TLDs were compared with ion chamber readings and TLD extrapolation to determine the effective depth of the TLD measurement. In vivo measurements were made on patients receiving open-field treatments to the chest, abdomen, and groin. Skin entry dose or entry and exit dose were assessed in comparison with doses estimated from phantom measurements. Results: The effective depth of measurement in a 6 MV therapeutic x-ray beam was found to be about 0.10 srng TLD extrapolation as a comparison. Entrance surface dose measurements made on a solid water phantom agreed well with ion chamber and TLD extrapolation measurements, and black TLDs provide a more accurate exit dose than the other methods. Under clinical conditions, the black TLDs have an accuracy of ? 5 % (+ 2 SD). The dose predicted from black TLD readings correlate with observed skin reactions as assessed with reflectance spectroscopy. Conclusion: In viva doshuetry with carbon-loaded TLDs proved to be a useful tool in assessing the dose delivered to the basal cell layer in the skin of patients undergoing radiotherapy.

Physical characteristics of C/2001 OG108 determined via near-IR reflectance spectroscopy indicates that this object has a spectrum similar P-type asteroids. This comet may represent the transition between highly active Halley Family comets and extinct comets.