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‣ Ethanol electro-oxidation over Pt(h k l): Comparative study on the reaction intermediates probed by FTIR and SFG spectroscopies

GOMES, Janaina Fernandes; BUSSON, Bertrand; TADJEDDINE, Abderrahmane; TREMILIOSI-FILHO, Germano
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
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We have investigated the adsorbed intermediates of ethanol electro-oxidation at Pt(1 1 1), Pt(1 0 0) and Pt(1 1 0) using FTIR and SFG spectroscopies. Mainly, we focus on the CO formation. The aim of the present work is to compare the responses coming from two different surf, cc probes: a FTIR spectroscopy and SFG spectroscopy. Between 1800cm(-1) and 2300cm(-1), our MR and SFG results are in good agreement. Specifically in the case of the ethanol/Pt(1 1 1) interface, the SFG spectroscopy presents higher sensibility to the interface response compared to the FTIR spectroscopy. (c) 2008 Elsevier Ltd. All rights reserved.

‣ Effect of ceramic shade on the degree of conversion of a dual-cure resin cement analyzed by FTIR

Passos, Sheila P.; Kimpara, Estevão Tomomitsu; Bottino, Marco A.; Santos, Gildo C.; Rizkalla, Amin S.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 317-323
Português
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Objectives: The aim of this research was to evaluate the degree of monomer conversion of different resin cement shades when photocured under different feldspathic ceramic shades. The photocuring time was also evaluated as well as the translucency of each ceramic shade. Methods: Three VITA VM7 ceramic shades (Base Dentin 0M1, Base Dentin 2M2 and Base Dentin 5M3) were used to determine the translucency percentage. A spectrophotometer MiniScan was used to measure the opacity percentage of each specimen (2-mm-thick) and then the translucency was calculated. To measure the degree of conversion (DC), the resin cement (Variolink II; A3 Yellow and transparent) specimens (thickness: 100 μm) were photocured under a ceramic block (2-mm-thick) for 20 or 40 s. Specimens photocured without the ceramic block were used as control. Sixteen groups (n = 3) were evaluated. Micro-ATR/FTIR spectrometry was used to evaluate the extent of polymerization of all specimens after 24 h. The %DC was calculated of experimentally polymerized versus maximally polymerized composite. Results: The translucency percentages of 0M1, 2M2 and 5M3 ceramics were 12.41 (1.02)%, 5.75 (1.91)% and 1.07 (0.03)%, respectively. The %DC of both resin cement shades cured under ceramic 5M3 was significantly lower than the other groups (p < 0.05). The %DC of 0M1 groups exhibited no significant difference from 2M2 groups (p > 0.05)...

‣ Cross linked Poly (4-Vinylpyridine-Ethylene Glycol Dimethacrylate) Used for Preconcentration of Cd(II) and its Determination by Flow Injection Flame Atomic Absorption Spectrometry

Teixeira Tarley, Cesar Ricardo; Botteon Farias, Natalia Cristina; Lima, Giovana de Fatima; Oliveira, Fernanda Midori de; Bonfilio, Rudy; Dragunski, Douglas Cardoso; Clausen, Debora Nobile; Segatelli, Mariana Gava
Fonte: Aoac Int Publicador: Aoac Int
Tipo: Artigo de Revista Científica Formato: 605-611
Português
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The main purpose of this research was to synthesize crosslinked poly(4-vinylpyridine-ethylene glycol dimethacrylate) and evaluate its feasibility for highly sensitive and selective determination of Cd in water samples by using flow injection flame atomic absorption spectrometry. The crosslinked polymer, prepared by bulk polymerization, was characterized by FTIR spectrometry and scanning electron microscopy. The flow injection solid-phase method was based on preconcentration of 20.0 mL of sample through 100 mg of the polymer packed into a minicolumn at pH 8.25 using a flow rate of 6.0 mL/min, followed by elution with 1.0 M HNO3. The sample solution parameters influencing the preconcentration behavior of Cd ions, such as pH, buffer concentration, and flow rate, were simultaneously studied and optimized using? Doehlert matrix. Values of 0.10 mu g/L, 2.0-210 mu g/L, 32.3, 18/h, 9.7/min, and 0.62 mL were obtained for LOD, linear range, preconcentration factor, sample throughput, concentration efficiency, and consumption index, respectively. The effect of the presence of the inorganic cations Pb(II)...

‣ Desenvolvimento e aplicação de métodos cromatográficos no estudo de aglutinantes em pintura

Rodrigues, Ana Sofia Gomes
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2011 Português
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Tese de mestrado em Química, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011; O objectivo deste trabalho centrou-se na caracterização de aglutinantes usados em pinturas de cavalete, através das técnicas de cromatografia líquida de alta eficiência (HPLC) e da cromatografia gasosa acoplada à espectrometria de massa, com pirólise (Py-GC/MS). Os resultados foram complementados através da análise por micro-espectroscopia de infravermelho (µ-FTIR). Outro dos objectivos consistiu na mimetização dos processos de degradação que ocorrem em pinturas, através de envelhecimento artificial de filmes de tinta. Neste trabalho foram estudados três tipos de aglutinantes: gema de ovo, cola animal e óleo de linho. Foram preparados filmes de tintas com os aglutinantes puros e/ou misturas com diversos pigmentos, nomeadamente, azurite, vermelho de chumbo e branco de chumbo. A técnica de µ-FTIR possibilitou a identificação dos aglutinantes e dos pigmentos usados. Os resultados obtidos por HPLC, utilizando o método Pico-Tag, permitiram comprovar que esta é uma técnica útil na identificação de materiais proteicos. Através da análise das amostras contendo pigmentos e das amostras sujeitas ao envelhecimento artificial...

‣ Applying pyrolysis-gas chromatography/mass spectrometry to the identification of oriental lacquers: study of two lacquered shields

Frade, José Carlos; Ribeiro, Maria Isabel; Graça, José; Rodrigues, José
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2009 Português
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Oriental lacquers have been used as coating materials for thousands of years for wooden, ceramics, leather and metal objects. Lacquers are natural polymers obtained from three species growing in different regions of Asia: Rhus vernicifera (China, Japan and Korea); Rhus succedanea (Vietnam and Taiwan); and Melanorrhoea usitate (Myanmar and Thailand). The identification of lacquer films is important for conservation and restoration purposes, as well as for art history studies because it may help in determining the origin of the lacquered objects. In this work, pyrolysis-gas chromatography/mass spectrometry using a filament-type pyrolyser was successfully applied to the characterization of oriental lacquers. A method to identify the three kinds of lacquer was developed and applied to the study of two lacquered shields imported from Asia in the sixteenth century. The materials that constitute the shields were also examined by Fourier-transform infrared microspectroscopy and details of the lacquering technique are reported

‣ FTIR, a powerful technique in organic coatings failure diagnosis

Costa, M. Rosário; Santos, M. Teresa; Diamantino, Teresa C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
Relevância na Pesquisa
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FTIR spectrometry (Fourier Transform Infrared) is an instrumental technique of analysis that presents significant advantages on the dispersive traditional system, such as the increase of the relation signal-noise, the capacity of getting absorption spectra of low energy and therefore, bands of absorption of weak intensity. This technique is widely used in the study of resin characterization and evaluation of polymeric materials as well as degradation when polymers and coatings are exposed to various conditions of service, or still in the analysis and diagnosis of defects that occur during the application or production process. Techniques connected to the FTIR have appeared such as the photoacoustic (PAS-FTIR), the microscopy (MCT-FTIR) and the attenuated total reflectance (ATR), which allows to analysis of weekly transparent and dark samples without removal of coatings from the substrates. The choice of the technique to use depends on the morphology of the surfaces to analyze and the type of failure (lack of adhesion, contamination, aging degradation, etc). This work illustrates the application of FTIR and associated techniques to identify causes of diverse types of defects in applied organic coatings on polymeric materials.

‣ Avaliação da eficiência das técnicas ESI-MS e ATR/FTIR na determinação de adulteração de BX com querosene e óleo residual

Soares,Itânia Pinheiro; Russo,Renato Monteiro de Oliveira; Prates,Ravi Govinda Dardot; Augusti,Rodinei; Fortes,Isabel Cristina Pereira; Pasa,Vânya Márcia Duarte
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
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Direct infusion electrospray ionization mass spectrometry in the negative ion mode, ESI(-)-MS and Fourier transform infrared spectroscopy (FTIR) were used together with partial least squares (PLS) as a tool to determine B3 adulteration (B3 - mixture of 3% v/v of biodiesel in diesel) with kerosene and residual oil.

‣ Application of ftir in the determination of acrylate content in poly(sodium acrylate-co-acrylamide) superabsorbent hydrogels

Magalhães,Antônio Sávio G.; Almeida Neto,Manuel P.; Bezerra,Maslândia N.; Ricardo,Nágila M. P. S.; Feitosa,Judith P. A.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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Hydrogels have been prepared by free-radical solution copolymerization of acrylamide and sodium acrylate (NaAc), with molar ratio ranging from 25/75 to 80/20, respectively, using methylene bisacrylamide as the crosslinking agent. A FTIR spectroscopy procedure to determine the acrylate/acrylamide ratio in these hydrogels was proposed based on absorbance at 1410 cm-1 (nCOO-) and 2940 cm-1 (nCH and nCH2). A straight line with a good linear correlation coefficient (0.998) was obtained by plotting the acrylate content (Ac%) versus relative absorbance (Arel = A1410/A2940). Results were confirmed by the amount of sodium cation released in acid medium determined by atomic absorption spectrometry.

‣ Determination of sulfur in diesel using ATR/FTIR and multivariate calibration

Soares,Itânia Pinheiro; Rezende,Thais F.; Fortes,Isabel Cristina P.
Fonte: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Publicador: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
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The aim of this present work was to provide a more fast, simple and less expensive to analyze sulfur content in diesel samples than by the standard methods currently used. Thus, samples of diesel fuel with sulfur concentrations varying from 400 and 2500 mgkg-1 were analyzed by two methodologies: X-ray fluorescence, according to ASTM D4294 and by Fourier transform infrared spectrometry (FTIR). The spectral data obtained from FTIR were used to build multivariate calibration models by partial least squares (PLS). Four models were built in three different ways: 1) a model using the full spectra (665 to 4000 cm-1), 2) two models using some specific spectrum regions and 3) a model with variable selected by classic method of variable selection stepwise. The model obtained by variable selection stepwise and the model built with region spectra between 665 and 856 cm-1 and 1145 and 2717 cm-1 showed better results in the determination of sulfur content.

‣ Determination of biodiesel adulteration with raw vegetable oil from ATR-FTIR data using chemometric tools

Soares,Itânia P; Rezende,Thais F; Pereira,Rita de Cássia. C; Santos,Cláudio G. dos; Fortes,Isabel C. P
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2011 Português
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Three different biodiesel sources (cotton, castor and palm) were adulterated with raw soybean oil at concentrations ranging from 1-40% (m/m). These samples were analyzed by infrared spectrometry (MIR) and their spectra were studied at three different spectral ranges: full spectrum (4000-665 cm-1), and the spectral ranges of 1800-1700 cm-1 and 1800-1000 cm-1. To determine the source of biodiesel used in the adulterated system, the data were analyzed by PCA (principal components analysis) spectral analysis tool and the best segregation of the sources was obtained at the range of 4000-665 cm-1. The explained variance was of 99% for the first three components. To quantify the raw soybean oil partial least squares (PLS) tool was applied. The best results were obtained for the spectral range of 1800-1000 cm-1, with values of RMSEP (root mean square error of prediction) varying from 1.10 to 1.47% (m/m).

‣ Protein Conformation in Amorphous Solids by FTIR and by Hydrogen/Deuterium Exchange with Mass Spectrometry

Sinha, Sandipan; Li, Yunsong; Williams, Todd D.; Topp, Elizabeth M.
Fonte: The Biophysical Society Publicador: The Biophysical Society
Tipo: Artigo de Revista Científica
Português
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Solid-state hydrogen/deuterium exchange (ssHDX) with electrospray ionization mass spectrometry (ESI-MS) and Fourier transform infrared (FTIR) spectroscopy were used to assess protein conformation in amorphous solids. Myoglobin, lysozyme, β-lactoglobulin, ribonuclease A, E-cadherin 5, and concanavalin A were co-lyophilized with carbohydrates (trehalose, raffinose, and dextran 5000), linear polymers (polyvinyl alcohol and polyvinyl pyrrolidone) or guanidine hydrochloride (negative control). For ssHDX, samples were exposed to D2O vapor at 33% relative humidity and room temperature, and then reconstituted at low temperature (4°C) and pH 2.5 and analyzed by ESI-MS. Peptic digestion of selected proteins was used to provide region-specific information on exchange. FTIR spectra were acquired using attenuated total reflectance. FTIR and ssHDX of intact proteins showed preservation of structure by raffinose and trehalose, as indicated by FTIR band intensity and protection from exchange. ssHDX of peptic digests further indicated that these protective effects were not exerted uniformly along the protein sequence but were observed primarily in α-helical regions, a level of structural resolution not afforded by FTIR. The results thus demonstrate the utility of HDX with ESI-MS for analyzing protein conformation in amorphous solid samples.

‣ Structural changes that occur upon photolysis of the Fe(II)a3 - CO complex in the cytochrome ba3-oxidase of Thermus thermophilus: A combined X-ray crystallographic and infrared spectral study demonstrates CO binding to CuB

Liu, Bin; Zhang, Yang; Sage, J. Timothy; Soltis, S. Michael; Doukov, Tzanko; Chen, Ying; Stout, C. David; Fee, James A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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The purpose of the work was to provide a crystallographic demonstration of the venerable idea that CO photolyzed from ferrous heme-a3 moves to the nearby cuprous ion in the cytochrome c oxidases. Crystal structures of CO-bound cytochrome ba3-oxidase from Thermus thermophilus, determined at ~ 2.8 – 3.2 Å resolution, reveal a Fe-C distance of ~2.0 Å, a Cu-O distance of 2.4 Å and a Fe-C-O angle of ~126°. Upon photodissociation at 100 K, X-ray structures indicate loss of Fea3-CO and appearance of CuB-CO having a Cu-C distance of ~1.9 Å and an O-Fe distance of ~2.3 Å. Absolute FTIR spectra recorded from single crystals of reduced ba3–CO that had not been exposed to X-ray radiation, showed several peaks around 1975 cm−1; after photolysis at 100 K, the absolute FTIR spectra also showed a significant peak at 2050 cm−1. Analysis of the “light’ minus ‘dark’ difference spectra showed four very sharp CO stretching bands at 1970 cm−1, 1977 cm−1, 1981 cm−1, and 1985 cm−1, previously assigned to the Fea3-CO complex, and a significantly broader CO stretching band centered at ~2050 cm−1, previously assigned to the CO stretching frequency of CuB bound CO. As expected for light propagating along the tetragonal axis of the P43212 space group...

‣ Obtención de hidroxiapatita sintética por tres métodos diferentes y su caracterización para ser utilizada como sustituto óseo; Revista Colombiana de Ciencias Químico Farmacéuticas

Sequeda Castañeda, Luis Gonzalo; Díaz Peraza, José Milciades; Gutiérrez Prieto, Sandra Janeth; Perdomo, Sandra Janeth; Gómez González, Olga Lucía
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 50-66
Português
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Vol. 41, no. 1; El método de obtención de la hidroxiapatita (HAp) para ser utilizada como sustituto óseo, debe ofrecer un producto de alta pureza, rendimiento, rapidez y bajo costo, y contar con propiedades como bioactividad, biocompatibilidad, osteoconductividad y unión directa al hueso. En este trabajo se elaboró HAp sintética mediante tres métodos reportados en la literatura de vía sinterización y vía precipitación. El material obtenido se caracterizó por espectrometría de absorción atómica (aas), espectrometría de absorción molecular (UV-Vis), espectroscopía infrarroja con transformada de Fourier (ftir), difracción de rayos X (XRD), microscopía electrónica de barrido (SEM) y espectroscopía por dispersión de energía de rayos X (EDX). La ruta de síntesis de HAp por precipitación ofreció mejores resultados, comparados con la muestra estándar comercial y el hueso bovino, obteniéndose un tamaño de grano aproximado de 1 µm, relación molar Ca/P de 1,7, alta pureza y cristalinidad; mientras que los resultados obtenidos por vía sinterización mostraron la presencia de fases amorfas. El método de síntesis por precipitación vía húmeda usando nitratos de calcio y fosfatos, mostró ser práctico y adecuado para realizar la inmovilización de HAp sobre un soporte metálico como silicio...

‣ Synthesis of Nano-Pore Size Ag(I)-Imprinted Polymer for the Extraction and Preconcentration of Silver Ions Followed by Its Determination with Flame Atomic Absorption Spectrometry and Spectrophotometry Using Localized Surface Plasmon Resonance Peak of Silver Nanoparticles

Dadfarnia,Shayessteh; Shabani,Ali Mohammad Haji; Kazemi,Elahe; Ahmad,Seyed; Khormizi,Heydari; Tammadon,Fattema
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 Português
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Silver ion imprinted polymer (IIP) was synthesized in the presence of Ag(I)-N,N’‑bis(salicylidene)ethylenediamine (salen) complex using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, and 2,2-azobis(isobutyronitrile) (AIBN) as the initiator. The Ag(I)-imprinted polymer (IIP) particles were characterized by SEM (scanning electron microscope), FTIR (Fourier transform infrared spectroscopy) and BET/BJH (Brunauer-Emmett-Teller/Barrett-Joyner-Halenda) analysis. The imprinted Ag(I) ions were completely removed by leaching the IIP with thiourea (0.5 mol L-1). The polymer was employed as a selective sorbent for extraction and separation of the trace amounts of the Ag(I) ions. The preconcentrated ion was determined via the flame atomic absorption spectrometry (FAAS) or it was reduced to silver nanoparticles and quantified by spectrophotometry based on its localized surface plasmon resonance peak (LSPRP). The figures of merit of both methods were compared. Under the optimized conditions, a sample volume of 80 mL resulted in an enhancement factor of 312. The detection limit (3Sb/m) and the relative standard deviation (n = 10) at 10 µg L-1 level for FAAS were found to be 0.06 µg L-1...

‣ HYDROXYPHENOL INTERACTIONS WITH IRON AND ALUMINUM OXIDE COLLOIDS BY CHEMICAL FORCE SPECTROMETRY

ABD. RAHMAN AZMI, ALYZA AZZURA
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
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Tannins and humic substances commonly referred to as natural organic matter (NOM), constitute an important component of natural water and soil systems. These species contain numerous phenol and carboxyl functional groups whose reactivity is strongly dependent on both the quantity and location of these moieties on the aromatic ring. In the realistic environmental conditions, both phenolic and carboxylic functional groups are adsorbed on a variety of colloidal metal oxide surfaces. Unfortunately, due to the complexity of humic-based substances, experimental data involving mineral-humate interactions are difficult to interpret. Here, we aim to develop a more detailed understanding of mineral-NOM interactions in aquatic systems, using self-assembled monolayers (SAMs) of simple organic acids having functional groups similar to those found in humic substances. SAMs of 4-(12-mercaptododecyl)benzene-1,2-diol (o-hydroxyphenol-terminated), 5-(12-mercaptododecyl)benzene-1,3-diol (m-hydroxyphenol-terminated), bis(11-thioundecyl) hydrogen phosphate (monoprotic phosphate) and 11-thioundecyl dihydrogen phosphate (diprotic phosphate) were prepared and deposited on a Au(111) surface. The composition of elements present on the surface were determined by X-ray Photoelectron Spectroscopy (XPS) and the orientation of monolayers on the Au(111) surface was explored by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Chemical force spectrometry has been used to determine the surface pKa of the monolayers and further used to explore the role of phenolic groups in the surface complexation of NOM by monitoring adhesion forces between iron and aluminum oxide sample and hydroxyphenol-terminated Atomic Force Microscopy (AFM) modified tip. The results are discussed in the context of hydrogen bonding between corresponding species. The system in which there are multiple hydroxyl groups ortho to the carboxylic groups or adjacent to one another on the benzene ring results in significantly different force-distance profiles when interacting with the hydroxyphenol tip.; Thesis (Ph.D...

‣ IR color separation in transmission through gratings on (110) silicon: FTIR experiment versus theory

Auslender, Mark; Hava, Shlomo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/04/2012 Português
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The phenomenon of filtering in zero-diffraction order is studied for transmission through 1D-periodic structures on a silicon wafer. Our study combines FTIR spectrometry in the range from 2.5 to 25 microns, and a rigorous full-vector simulation. The phenomenon exhibits itself as 'bright' and 'dark' bands in the spectra of normal transmission through grating samples, which replace each other quasi-periodically with respect to wave number, at wavelengths smaller than the grating period. The transmission modulation ratio is extremely high for two-side polished samples. Good agreement between the rigorous theory and experiment both in the range of the transmission oscillations and in the region of enhanced absorption is obtained; Comment: 3 pages, 2 figures; Fourier Transform Spectroscopy (FTS) Santa Barbara, California, June 22, 1999; Paper FThA3 in Fourier Transform Spectroscopy: New Methods and Applications, OSA Technical Digest (Optical Society of America, 1999)

‣ Hardware and software optimization of fourier transform infrared spectrometry on hybrid-FPGAs

Bekker, Dmitriy
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
58.00118%
With the increasing complexity of today’s spacecrafts, there exists a concern that the on-board flight computer may be overburdened with various processing tasks. Currently available processors used by NASA are struggling to meet the requirements of scientific experiments [1, 2]. A new computational platform will soon be needed to contend with the increasing demands of future space missions. Recently developed hybrid field-programmable gate arrays (FPGA) offer the versatility of running diverse software applications on embedded processors while at the same time taking advantage of reconfigurable hardware resources, all on the same chip package. These tightly coupled HW/SW systems consume less power than general-purpose singleboard computers (SBC) and promise breakthrough performance previously impossible with traditional processors and reconfigurable devices. This thesis takes an existing floating-point intensive data processing algorithm, used for on-board spacecraft Fourier transform infrared (FTIR) spectrometry, ports it into the embedded PowerPC 405 (PPC405) processor, and evaluates system performance after applying different hardware and software optimizations and architectural configurations of the hybrid-FPGA. The hardware optimizations include Xilinx’s floating-point unit (FPU) for efficient single-precision floating-point calculations and a dedicated single-precision dot-product co-processor assembled from basic floating-point operator cores. The software optimizations include utilizing a non-ANSI single-precision math library as well as IBM’s PowerPC performance libraries recompiled for double-precision arithmetic only. The outcome of this thesis is a fully functional...

‣ FTIR, a powerful technique in organic coatings failure diagnosis

Costa, Maria do Rosário; Santos, M. Teresa; Diamantino, Teresa C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 08/09/2009 Português
Relevância na Pesquisa
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FTIR spectrometry (Fourier Transform Infrared) is an instrumental technique of analysis that presents significant advantages on the dispersive traditional system, such as the increase of the relation signalnoise, the capacity of getting absorption spectra of low energy and therefore, bands of absorption of weak intensity. This technique is widely used in study, resin characterization and evaluation of polymeric materials as well as of its degradation when exposed to the most varied conditions of service, or still in the analysis and diagnosis of defects that occur during the application or production process. Techniques connected to the FTIR had more recently appeared as the photoacoustic (PAS-FTIR), the microscopy (MCT-FTIR) and the attenuated total reflectance (ATR), which allow to analyze weekly transparent and dark samples without removal of coatings from the substrates. The choice of the technique to use depends on the morphology of the surfaces to analyze and the type of failure in cause (lack of adhesion, contamination, aging degradation, etc). In this work the application of FTIR and techniques associates to the identification of the causes that had originated diverse types of defect in applied organic coatings on polymeric materials is presented. Key words: FTIR...

‣ Analysis of Portuguese Wines by Fourier Transform Infrared Spectrometry (Ftir)

Moreira,J. L.; Marcos,A. M.; Barros,P.
Fonte: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional) Publicador: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2002 Português
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The aim of this work is to present the results of the experimental optimisation of the essays with FTIR, supported by analytical data obtained by the methods that the laboratory routinely applies. The use of FTIR in Enology -an emergent and very promising methodology -must be based on specific analytical calibrations established through the quantification by usual physical and chemical methods of the parameters to analyse. The global calibration obtained for the analysis of wines allows good results for all parameters. The specific calibration performed leads, in the case of the total sugars, to more adjusted results to the values given by the analytical methods in routine, being the use of a general or specific calibration indifferent for the remaining studied parameters

‣ Proficiency Test on Ftir Wine Analysis

Moreira,J. L.; Marcos,A. M.; Barros,P.
Fonte: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional) Publicador: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2002 Português
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The FTIR (Fourier Transform Infrared) technology has recently become one of the greatest improvements in the routine work of a wine analysis laboratory. In Portugal a workgroup of laboratories equipped with FTIR wine analysers has been created in order to optimise this methodology. One of the most important tasks of this workgroup was to carry out a proficiency test for FTIR analysers. This test consisted in the analysis of the same sample by all the participants, using a FTIR wine analyser provided with the same analytical calibration and using the same procedure. The results obtained presented good reproducibility in what the most relevant parameters are concerned. This proficiency test enables a more effective quality control of the FTIR results of each laboratory and became an important tool to detect several malfunctions in the equipments of the participants.