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1.
ACS Sustain Chem Eng ; 12(5): 1897-1910, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38333206

RESUMO

Economically viable production of biobased products and fuels requires high-yielding, high-quality, sustainable process-advantaged crops, developed using bioengineering or advanced breeding approaches. Understanding which crop phenotypic traits have the largest impact on biofuel economics and sustainability outcomes is important for the targeted feedstock crop development. Here, we evaluated biomass yield and cell-wall composition traits across a large natural variant population of switchgrass (Panicum virgatum L.) grown across three common garden sites. Samples from 331 switchgrass genotypes were collected and analyzed for carbohydrate and lignin components. Considering plant survival and biomass after multiple years of growth, we found that 84 of the genotypes analyzed may be suited for commercial production in the southeastern U.S. These genotypes show a range of growth and compositional traits across the population that are apparently independent of each other. We used these data to conduct techno-economic analyses and life cycle assessments evaluating the performance of each switchgrass genotype under a standard cellulosic ethanol process model with pretreatment, added enzymes, and fermentation. We find that switchgrass yield per area is the largest economic driver of the minimum fuel selling price (MSFP), ethanol yield per hectare, global warming potential (GWP), and cumulative energy demand (CED). At any yield, the carbohydrate content is significant but of secondary importance. Water use follows similar trends but has more variability due to an increased dependence on the biorefinery model. Analyses presented here highlight the primary importance of plant yield and the secondary importance of carbohydrate content when selecting a feedstock that is both economical and sustainable.

2.
Philos Trans A Math Phys Eng Sci ; 374(2082)2016 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-27799427

RESUMO

Non-destructive pigment analysis by Raman microscopy (RM) and portable X-ray fluorescence (pXRF) has been carried out on some Bolognese illuminations and cuttings chosen to represent the beginnings, evolution and height of Bolognese illuminated manuscript production. Dating to the thirteenth and fourteenth centuries and held in a private collection, the study provides evidence for the pigments generally used in this period. The results, which are compared with those obtained for other north Italian artwork, show the developments in usage of artistic materials and technique. Also addressed in this study is an examination of the respective roles of RM and pXRF analysis in this area of technical art history.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.

4.
Artigo em Inglês | MEDLINE | ID: mdl-24177870

RESUMO

Complementary spectroscopic methods were used to characterize ceramic body and black coating of fine pottery found at Pompeii (Italy). This has enabled us to investigate local productions and to clarify the technological changes over the 4th-1st centuries BC. Two different groups of ceramics were originally distinguished on the basis of macroscopic observations. Optical microscopy (OM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) seem to indicate the usage of the same raw materials for the production of black-coated ceramics at Pompeii for about three centuries. Raman microscopy (RM) and micro-analysis (SEM/EDS) suggest different production treatments for both raw material processing and firing practice (duration of the reducing step and the cooling rate).


Assuntos
Cerâmica/química , Cerâmica/história , Minerais/análise , História Antiga , Itália , Teste de Materiais , Microscopia , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Difração de Raios X
5.
ACS Comb Sci ; 15(9): 458-63, 2013 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-23902344

RESUMO

High-throughput continuous hydrothermal flow synthesis was used to manufacture 66 unique nanostructured oxide samples in the Ce-Zr-Y-O system. This synthesis approach resulted in a significant increase in throughput compared to that of conventional batch or continuous hydrothermal synthesis methods. The as-prepared library samples were placed into a wellplate for both automated high-throughput powder X-ray diffraction and Raman spectroscopy data collection, which allowed comprehensive structural characterization and phase mapping. The data suggested that a continuous cubic-like phase field connects all three Ce-Zr-O, Ce-Y-O, and Y-Zr-O binary systems together with a smooth and steady transition between the structures of neighboring compositions. The continuous hydrothermal process led to as-prepared crystallite sizes in the range of 2-7 nm (as determined by using the Scherrer equation).


Assuntos
Cério/química , Ensaios de Triagem em Larga Escala , Nanoestruturas/química , Oxigênio/química , Temperatura , Ítrio/química , Zircônio/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-23557776

RESUMO

Barium sulfate, BaSO4, is shown by Raman microscopy to be readily identifiable in early (1920s) industrially produced anatase (TiO2) and thus, if present, may act as a date marker for early industrial anatase. Later processes (except that for producing Titanox B) did not involve usage of barium sulfate. The matter is relevant to the possible dating of certain artwork.


Assuntos
Arte/história , Sulfato de Bário/análise , Corantes/análise , Titânio/análise , Sulfato de Bário/história , Corantes/história , História do Século XX , Análise Espectral Raman , Titânio/história
7.
Analyst ; 138(3): 729-34, 2013 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-23236600

RESUMO

The key contributions of the four great Nobel Laureates - Lord Rayleigh, Sir William Ramsay, Lord Rutherford and Sir Chandrasekhara Raman - to the understanding of light scattering, to the identification and classification of the rare gases, and to the discovery in 1928 of the Raman effect are outlined. The interactions between these scientists are explored, in particular those of Rayleigh with Ramsay (in establishing the physics and chemistry of the rare gases), Ramsay with Rutherford (on studies of the radioactivity of radium dibromide and on the discovery of radon and its position in the periodic table), and Rutherford with Raman (in supporting Raman's career via the Royal Society and as a nominee for the Nobel Prize). The resilience and dedication of these scientific pioneers is emphasised, noting in particular that Rutherford and Raman emerged with success from unlikely backgrounds and from countries far removed from the then centres of scientific excellence. Key developments from 1928 onwards in the light sources used for the excitation of Raman spectra and in the detectors of Raman scattered radiation are outlined. Attention is drawn to the mounting number of scientific areas which continue to be opened up by Raman microscopy and many other derived techniques such as SERS, TERS, etc.

8.
Artigo em Inglês | MEDLINE | ID: mdl-22402575

RESUMO

The palette of four Persian manuscripts of the 16th and 17th centuries were established by Raman microscopy to include lazurite, red lead, vermilion, orpiment, a carbon-based black, lead white, malachite, haematite, indigo, carmine and pararealgar. The first five pigments were identified on all four manuscripts, as previously found for other Islamic manuscripts of this period. The findings were compared with information available in treatises on Persian painting techniques. Red lead, although identified on all of the manuscripts analysed in this study as the main red pigment, is seldom mentioned in the literature. Two unusual pigments were also identified: the intermediate phase between realgar and pararealgar in the manuscript Timur namah, and carmine in the manuscript Shah namah. Although the established palette comprises few pigments, it was found that the illuminations were enhanced by the use of pigment mixtures, the components of which could be identified by Raman microscopy.


Assuntos
Corantes/análise , Manuscritos como Assunto/história , Análise Espectral Raman/métodos , História do Século XVI , História do Século XVII , Microscopia/métodos , Pinturas/história , Pérsia
9.
Nephrol Dial Transplant ; 26(12): 4140-2, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21926403

RESUMO

We describe the case of a 48-year-old man with an acute nephritis and respiratory failure. Clinical history, streptococcal antibody titres and renal biopsy led to a diagnosis of post-streptococcal glomerulonephritis. Respiratory investigations excluded pulmonary oedema and infection. We hypothesize that this man had a co-existing post-streptococcal glomerulonephritis and an immune-mediated pneumonitis. This is a very rare association, which was last described in 1982.


Assuntos
Glomerulonefrite/complicações , Glomerulonefrite/microbiologia , Pneumonia/imunologia , Infecções Estreptocócicas/complicações , Humanos , Masculino , Pessoa de Meia-Idade
10.
Philos Trans A Math Phys Eng Sci ; 368(1927): 4331-49, 2010 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-20732890

RESUMO

High-throughput continuous hydrothermal flow synthesis has been used as a rapid and efficient synthetic route to produce a range of crystalline nanopowders in the Ce-Zn oxide binary system. High-resolution powder X-ray diffraction data were obtained for both as-prepared and heat-treated (850 degrees C for 10 h in air) samples using the new robotic beamline I11, located at Diamond Light Source. The influence of the sample composition on the crystal structure and on the optical and physical properties was studied. All the nanomaterials were characterized using Raman spectroscopy, UV-visible spectrophotometry, Brunauer-Emmett-Teller surface area and elemental analysis (via energy-dispersive X-ray spectroscopy). Initially, for 'as-prepared' Ce(1-x)Zn(x)O(y), a phase-pure cerium oxide (fluorite) structure was obtained for nominal values of x=0.1 and 0.2. Biphasic mixtures were obtained for nominal values of x in the range of 0.3-0.9 (inclusive). High-resolution transmission electron microscopy images revealed that the phase-pure nano-CeO(2) (x=0) consisted of ca 3.7 nm well-defined nanoparticles. The nanomaterials produced herein generally had high surface areas (greater than 150 m(2) g(-1)) and possessed combinations of particle properties (e.g. bandgap, crystallinity, size, etc.) that were unobtainable or difficult to achieve by other more conventional synthetic methods.

11.
Proc Natl Acad Sci U S A ; 107(13): 5726-31, 2010 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-20304797

RESUMO

Italian medieval and Renaissance manuscript cuttings and miniatures from the Victoria and Albert Museum were analyzed by Raman microscopy to compile a database of pigments used in different periods and different Italian regions. The palette identified in most manuscripts and cuttings was found to include lead white, gypsum, azurite, lazurite, indigo, malachite, vermilion, red lead, lead tin yellow (I), goethite, carbon, and iron gall ink. A few of the miniatures, such as the historiated capital "M" painted by Gerolamo da Cremona and the Petrarca manuscript by Bartolomeo Sanvito, are of exceptional quality and were analyzed extensively; some contained unusual materials. The widespread usage of iron oxides such as goethite and hematite as minor components of mixtures with azurite is particularly notable. The use of a needle-shaped form of iron gall ink as a pigment rather than a writing material was established by both Raman microscopy and x-ray fluorescence spectroscopy for the Madonna and Child by Franco de' Russi.

12.
Dalton Trans ; 39(3): 711-4, 2010 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-20066213

RESUMO

A novel and rapid and continuous hydrothermal route to the synthesis of extensive ultra-thin 2D sodium titanate (Na(2)Ti(3)O(7)) nano-sheets using a superheated water flow at 450 degrees C and 24.1 MPa as a crystallizing medium is described. High resolution electron microscopy of the sheets revealed that they were a few layers thick and largely uncurled, highly crystalline despite their very short time under hydrothermal flow conditions. The sodium titanate sheets possessed excellent photocatalytic activity for decolourisation of methylene blue dye.

13.
Appl Spectrosc ; 63(6): 611-20, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19531288

RESUMO

Metallic bismuth, pyrite (FeS2), and specular hematite (Fe2O3) were found to have been used extensively on two miniatures taken from the Book of Hours of Louis XII by Jean Bourdichon, painter at the Royal Court of France between the end of the 15th and the beginning of the 16th centuries. These unusual materials were identified, together with thirteen other more traditional pigments and dyes, by Raman microscopy and X-ray fluorescence. Pyrite was found in many areas, suggesting that it may have been deliberately added as a pigment. The luminary quality of both miniatures was enhanced by the extensive use of shell gold throughout, but other less common materials such as specular hematite and mosaic gold were also utilized. Metallic bismuth was used, alone or in admixture with other pigments, to create a soft gray color. Its identification as a paint material was complemented by the study of the optical and visual properties of standard samples of metallic bismuth and several bismuth compounds. Evidence for the use of a bismuth pencil was also found.

14.
Anal Chem ; 80(5): 1482-92, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18247519

RESUMO

Seventeen samples from paintings by the distinguished 19th century Portuguese painter, Henrique Pousão, were characterized by micro-X-ray diffractometry and infrared and Raman microspectroscopy. The main advantages and limitations of each technique for pigment identification are outlined, revealing the need for the use of complementary techniques. Pousão's palette is discussed.

15.
Philos Trans A Math Phys Eng Sci ; 366(1862): 5-14, 2008 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-17827130

RESUMO

Mixed-valence compounds were recognized by chemists more than a century ago for their unusual colours and stoichiometries, but it was just 40 years ago that two seminal articles brought together the then available evidence. These articles laid the foundations for understanding the physical properties of such compounds and how the latter correlate with molecular and crystal structures. This introduction to a discussion meeting briefly surveys the history of mixed valence and sets in context contributions to the discussion describing current work in the field.

16.
Respir Med ; 101(5): 1021-5, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17088053

RESUMO

Occupational asbestos exposure has been endemic in Portsmouth. A retrospective case note analysis of 50 patients who underwent thoracoscopy over a 2-year period from January 2003 was undertaken. Biopsies were taken in 47 cases, 31 of which showed malignant mesothelioma. Thirty seven percent of those without a history of direct exposure to asbestos had mesothelioma, implying that even in the absence of an exposure history a low threshold for investigation should be adopted for the local population. There was no mortality or significant morbidity associated with the procedure. Medical thoracoscopy is safe and effective in the diagnosis of benign and malignant pleural disease particularly in this high risk population.


Assuntos
Mesotelioma/diagnóstico , Neoplasias Pleurais/diagnóstico , Toracoscopia/métodos , Idoso , Idoso de 80 Anos ou mais , Amianto/efeitos adversos , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Mesotelioma/etiologia , Pessoa de Meia-Idade , Doenças Profissionais/diagnóstico , Doenças Profissionais/etiologia , Doenças Pleurais/diagnóstico , Derrame Pleural/etiologia , Derrame Pleural Maligno/diagnóstico , Derrame Pleural Maligno/etiologia , Neoplasias Pleurais/etiologia , Estudos Retrospectivos , Toracoscopia/efeitos adversos
17.
Anal Chem ; 77(11): 3611-22, 2005 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-15924396

RESUMO

The King George III copy of the Gutenberg Bible, held at the British Library, has been analyzed using Raman spectroscopy to determine the palette of pigments used in the illuminations on this work. The palette is found to comprise cinnabar/vermilion, lead tin yellow (type 1), carbon-based black, azurite, malachite, an organo-copper complex (a "verdigris"), calcium carbonate (chalk), gypsum, gold leaf, and basic lead carbonate ("lead white"). This is in agreement with contemporary descriptions of the pigments used for the illuminations. One pigment could not be identified, specifically the organic dark red/purple color used for the foliage. The palette of this copy of the Gutenberg Bible has been compared with those used for six other copies, held at Eton College and Lambeth Palace, England, the Bibliothèque Mazarine and the Bibliothèque nationale de France, and the Staatsbibliothek zu Berlin and the Niedersachsische Staats- und Universitatsbibliothek (SUB) Göttingen, Germany. The palettes are shown to be similar to one another, even though the styles of the primary illuminations differ. The two Gutenberg Bibles held in Germany, printed on vellum, have the more expensive palettes, which include lazurite. The SUB Göttingen copy has the most extensive palette with 16 pigment-related materials having been identified.


Assuntos
Bíblia , Corantes/análise , Tinta , Livros Raros , Análise Espectral Raman/métodos , Sensibilidade e Especificidade
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 61(7): 1389-93, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15820871

RESUMO

Photolyses of matrices of either BrCHCHBr/NO2/Ar or ClCHCHCl/NO2/Ar using quartz-filtered radiation (lambda>240 nm) led to the appearance of infrared bands attributable to carbonyl, carbon monoxide, and ketene species; no bands belonging to a precursor complex NO2cdots, three dots, centeredXCHCHX (where X=Br or Cl) were observed upon matrix deposition. The possible reaction pathway is discussed.


Assuntos
Dicloroetilenos/química , Dibrometo de Etileno/química , Dióxido de Nitrogênio/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Bromo/química , Carbono/química , Monóxido de Carbono/química , Cloro/química , Luz , Modelos Químicos , Conformação Molecular , Óxido Nítrico , Fotoquímica/métodos , Espectrofotometria Infravermelho
19.
Anal Chem ; 77(5): 1261-7, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15732905

RESUMO

Technical examination of the painting Young Woman Seated at a Virginal by cross section and polarized light microscopy, chemical tests, surface microscopy, energy-dispersive X-ray analysis, and Raman microscopy has led to the identification of the pigments lead tin yellow (type I), lazurite, vermilion, calcite, lead white, red and yellow iron oxides, umber, lamp black, and green earth on the canvas. These pigments are entirely typical of Vermeer's palette and are consistent with a large body of other technical and art historical findings on paintings by Vermeer and other Dutch 17th century artists. While not authenticating the painting as being by Vermeer, the results provide further critical material that is consistent with this attribution. This case study also provides an opportunity to outline the role of analytical and forensic sciences in the examination and attribution of art objects.

20.
Inorg Chem ; 43(20): 6334-44, 2004 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-15446881

RESUMO

A series of compounds of the form [M(2)L(4)] and [[((t)()BuCO(2))(3)M(2)](2)(mu-L')] have been made where M = Mo or W, L = a thienyl, bithienyl, or terthienyl carboxylate, and L' = a corresponding thienyl dicarboxylate. The electronic absorption spectra are reported and the electronic structures discussed. Intense metal-to-ligand charge transfer bands traverse the visible and near-IR regions of the electronic absorption spectrum. The compounds show reversible metal-based oxidations and quasireversible ligand-based reductions. The molecular structure of Mo(2)(O(2)C-2-Th)(4).2THF is reported, on the basis of a single crystal X-ray diffraction study. These compounds provide insight into the expected properties of related dimetalated polythiophenes incorporating MM quadruple bonds.


Assuntos
Ácidos Carboxílicos/química , Modelos Químicos , Molibdênio/química , Compostos Organometálicos/síntese química , Tiofenos/química , Tungstênio/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Estrutura Molecular , Compostos Organometálicos/química , Tiofenos/síntese química
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