992 resultados para FT-RS


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Samples taken from middens at the Neolithic site of Catalhoyuk in Turkey have been analysed using IR spectroscopy backed up by powder XRD and SEM-EDX. Microcomponents studied include fossil hack-berries (providing evidence of ancient diet and seasonality), mineral nodules (providing evidence of post-depositional change) and phytoliths (mineralised plant cells, providing evidence of usage of plant species). Finely laminated ashy deposits have also been investigated allowing chemical and mineralogical variations to be explored. It is found that many layers which appear visually to be quite distinctive have, in fact, very similar mineralogy. (C) 2009 Elsevier B.V. All rights reserved.

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A range of archaeological samples have been examined using FT-IR spectroscopy. These include suspected coprolite samples from the Neolithic site of Catalhoyuk in Turkey, pottery samples from the Roman site of Silchester, UK and the Bronze Age site of Gatas, Spain and unidentified black residues on pottery sherds from the Roman sites of Springhead and Cambourne, UK. For coprolite samples the aim of FT-IR analysis is identification. Identification of coprolites in the field is based on their distinct orange colour; however, such visual identifications can often be misleading due to their similarity with deposits such as ochre and clay. For pottery the aim is to screen those samples that might contain high levels of organic residues which would be suitable for GC-MS analysis. The experiments have shown coprolites to have distinctive spectra, containing strong peaks from calcite, phosphate and quartz; the presence of phosphorus may be confirmed by SEM-EDX analysis. Pottery containing organic residues of plant and animal origin has also been shown to generally display strong phosphate peaks. FT-IR has distinguished between organic resin and non-organic compositions for the black residues, with differences also being seen between organic samples that have the same physical appearance. Further analysis by CC-MS has confirmed the identification of the coprolites through the presence of coprostanol and bile acids, and shows that the majority of organic pottery residues are either fatty acids or mono- or di-acylglycerols from foodstuffs, or triterpenoid resin compounds exposed to high temperatures. One suspected resin sample was shown to contain no organic residues. and it is seen that resin samples with similar physical appearances have different chemical compositions. FT-IR is proposed as a quick and cheap method of screening archaeological samples before subjecting them to the more expensive and time-consuming method of GC-MS. This will eliminate inorganic samples such as clays and ochre from CC-MS analysis, and will screen those samples which are most likely to have a high concentration of preserved organic residues. (C) 2008 Elsevier B.V. All rights reserved.

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Samples taken from middens at the Neolithic site of Catalhoyuk in Turkey have been analysed using IR spectroscopy backed up by powder XRD and SEM-EDX. Microcomponents studied include fossil hack-berries (providing evidence of ancient diet and seasonality), mineral nodules (providing evidence of post-depositional change) and phytoliths (mineralised plant cells, providing evidence of usage of plant species). Finely laminated ashy deposits have also been investigated allowing chemical and mineralogical variations to be explored. It is found that many layers which appear visually to be quite distinctive have, in fact, very similar mineralogy. (C) 2009 Elsevier B.V. All rights reserved.

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The solid-state transformation of carbamazepine from form III to form I was examined by Fourier Transform Raman spectroscopy. Using a novel environmental chamber, the isothermal conversion was monitored in situ at 130◦C, 138◦C, 140◦C and 150◦C. The rate of transformation was monitored by taking the relative intensities of peaks arising from two C H bending modes; this approach minimised errors due to thermal artefacts and variations in power intensities or scattering efficiencies from the samples in which crystal habit changed from a characteristic prism morphology (form III) to whiskers (form I). The solid-state transformation at the different temperatures was fitted to various solid-state kinetic models of which four gave good fits, thus indicating the complexity of the process which is known to occur via a solid–gas–solid mechanism. Arrhenius plots from the kinetic models yielded activation energies from 344 kJ mol−1 to 368 kJ mol−1 for the transformation. The study demonstrates the value of a rapid in situ analysis of drug polymorphic type which can be of value for at-line in-process control.

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Mannitol is a polymorphic excipient which is usually used in pharmaceutical products as the beta form, although other polymorphs (alpha and delta) are common contaminants. Binary mixtures containing beta and delta mannitol were prepared to quantify the concentration of the beta form using FT-Raman spectroscopy. Spectral regions characteristic of each form were selected and peak intensity ratios of beta peaks to delta peaks were calculated. Using these ratios, a correlation curve was established which was then validated by analysing further samples of known composition. The results indicate that levels down to 2% beta could be quantified using this novel, non-destructive approach. Potential errors associated with quantitative studies using FT-Raman spectroscopy were also researched. The principal source of variability arose from inhomogeneities on mixing of the samples; a significant reduction of these errors was observed by reducing and controlling the particle size range. The results show that FT-Raman spectroscopy can be used to rapidly and accurately quantitate polymorphic mixtures.

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Samples of Araucaria area soil from Parana state, Brazil, were separated by particle size fractionation and investigated by electron paramagnetic resonance (EPR) in X-Band of 9.5 GHz at room temperature and 77K, infra-red spectroscopy and X-ray diffractometry. The paramagnetic species in the soil samples were identified by comparison with EPR spectra of some minerals studied recently by our group, several soil types and/or soil components investigated in the literature. The value of g = 2.1 (Delta H = 85 mT) indicated the presence of ferrihydrite. Hematite was identified by g = 2.1 (Delta H = 100 mT) and g = 4.3 for Fe(3+) lines of the concentrated dominium and diluted dominium. Kaolinite was identified by IR and EPR with the resonance at g = 4.3 attributed to Fe(3+) ions in isolated sites of tetrahedral and octahedral symmetry with rhombic distortion. The resonances at g = 3.7 and g = 4.9 were attributed to Fe(3+) in more highly symmetrical environment than rhombic symmetry, but not in axial symmetry. Three signals around g = 2 were attributed to radiation defects, plus additional resonances at g = 2.8 and 9.0. Signals less intense than those at g = 2.1, 3.7, and 6.5, observed for clear grains of soil, were attributed to presence of Fe(3+) in quartz which was identified by IR and XDR. (C) 2011 Elsevier B.V. All rights reserved.

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The aim of the present study was to evaluate the effects of low-dose therapeutic ionizing radiation on different aesthetic dental materials. Forty five specimens (n = 45) of three different aesthetic restorative materials were prepared and randomly divided into five groups: G1 (control group); G2, G3, G4, G5 experimental groups irradiated respectively with 0.25, 0.50, 0.75, and 1.00 Gy of gamma radiation by the (60)Co teletherapy machine. Chemical analyses were performed using a FT-IR Nicolet 520 spectrophotometer with reflectance diffuse technique. Even a minimal exposition at ionizing radiation in therapeutic doses can provide chemical changes on light-cured composite resins. The three studied restorative materials showed changes after exposure at gamma radiation, however the increase of the radiation dose did not contribute to an increase in this effect.

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This work presents a FT-Raman study (lambda(0) = 1064 nm) of naturally occurring polyester poly[(R)-3-hydroxybutyrate] (PHB) and its copolymer poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] (PHBV) with 5,8 and 12 mol % of HV (hydroxyvalerate). The FT-Raman spectra of films indicate that full width at half height of the band centered at 1725 cm(-1) and relative intensity of bands at 1443 and 1458 cm(-1) can be use to estimate the crystalline degree in film samples. The similarity between Raman spectra of molten PHB and PHBV and theirs CDCl(3) solutions suggested that molten polymers present similar conformation than polymers in solution. Raman data of these samples showed that bands at 1220, 1402, 1725, 2998 and 3009 cm(-1) are due to crystalline helical structure and the bands at 1453, 1740, 2881, 2938 and 2990 cm(-1) are originated from disordered domains. It is shown that composition of PHBV samples can be estimated by analyzing the ratio of the intensity of the bands at 2938 cm(-1) (nu C-H) and 1740 cm(-1) (nu C=O) in the spectra of solutions and of bands at 1354 (wCH(2)) and 1740 cm(-1) (nu C=O) in spectra of molten polymers. (C) 2010 Elsevier B.V. All rights reserved.

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Raman and IR experiments have been carried out on formamide (FA) and pyridine (Py) mixtures at different compositions. The appearance of a new Raman band at 996 cm(-1) (nu(1) region of Py), whose intensity depends on the FA concentration, is assigned to an FA: Py adduct and this result is in excellent agreement with those of other authors who employed noisy light-based coherent Raman scattering spectroscopy (I((2)) CARS). Another band at 1587 cm(-1) (nu(8) region of Py) has been observed for the first time by using Raman and IR spectroscopies. Its intensity shows the same dependence on the FA concentration and this fact allows us to also attribute it to an FA: Py adduct. The good relationship between the Raman and IR data demonstrates the potential of the vibrational spectroscopy for this kind of study. Owing to higher absolute Raman scattering cross section, the nu(1) region of Py has been chosen for the quantitative analysis and a stoichiometry of 1 : 1 FA: Py is reported. The experimental data are very well supported by the density functional theory (OFT) calculation, which was employed for the first time to the present system. Furthermore, the actual investigation shows an excellent agreement with those reported from computational calculations for similar systems. A comparison with our previous studies confirms that: the solvent dielectric constant determines the stoichiometry of a given Lewis acid-base adduct in the infinite dilution limit. Copyright (C) 2009 John Wiley & Sons, Ltd.

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I denna uppsats har en undersökning av studenters alkoholvanor gjorts. Syftet med arbetet var att få en uppfattning om första års programstudenters alkoholvanor vid Högskolan Dalarna campus Borlänge. Följande frågeställningar belyses i studien: Hur ofta och hur mycket dricker studenter vid respektive program, hur ser kvinnornas alkoholvanor ut jämfört med männens, samt om alkoholvanorna skiljer sig mellan programmen.Jag har använt mig av en kvantitativ enkätundersökning där totalt 60 studenter från tre olika program har medverkat. Studenterna går första året på Högskolan Dalarna och är i åldrarna 19-24 år. De program som undersöktes var Grafisk teknologi och design, Materialdesign samt Ekonomprogrammet. Jag vill påpeka att bortfallet i undersökningen är litet och de flesta har svarat på enkäten (60/74). Vid ett eventuellt bortfall bör man fråga sig om de frånvarande studenterna skiljer sig avsevärt från de studenter som deltog i undersökningen. Orsaken till att några studenter inte var närvarande vid undersökningen kan jag inte uttala mig om.De teorier som används i uppsatsen är teorier om identitetsfinnande, rusets betydelse för konsumtionen, samt en teori om normer och avvikande beteende.Innan jag genomförde undersökningen tog jag kontakt med några av skolans studieadministratörer för att få tillgång till antal registrerade studenter på de olika programmen. Därefter tog jag kontakt med lärare på respektive program och bestämde datum och tid för utlämnande av enkäten. Då kunde jag själv dela ut och samla in enkäten. Efter att jag fått in svar på enkäten sammanställdes all information för att få en övergripande syn på studenternas alkoholvanor.Resultatet av undersökningen visar att 91,7% av studenterna konsumerar alkohol. Den visar också att männen dricker oftare än vad kvinnorna gör och även större mängder vid ett och samma tillfälle. Dock är det många kvinnor som dricker ofta och mycket. Detta kan bero på att de existerande könsroller som finns håller på att lösas upp.Studenter på Materialdesignprogrammet har högst konsumtion om man jämför med de övriga programmen. På detta program dricker många av studenterna fler än 1 gång i veckan. De dricker också stora mängder. Ekonomprogrammet har låg konsumtion både när det gäller hur ofta och hur mycket de dricker. Det mest häpnadsväckande resultatet har programmet Grafisk teknologi och design där det faktiskt är kvinnorna som står för den högsta konsumtionen.

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Det tobakspreventiva arbetet är en av samhällets största utmaningar.Syftet med studien var att beskriva tobaksbruket och dess förändring över tid (1983-2003) iett slumpmässigt urval av individer 15-70 år i Jönköpings kommun. Den specifikamålsättningen var att analysera tobaksvanorna i relation till socioekonomiska förhållanden,personlighet, tandvård och tandvårdsvanor. Studien utgjordes av tre epidemiologiskatvärsnittsstudier utförda åren 1983, 1993 och 2003. En klinisk och röntgenologiskundersökning utfördes av mun och tänder. Individerna fick även besvara ett frågeformulär.Resultaten visade en statistiskt signifikant minskning av tobaksbruket från 31 %tobaksbrukare 1983 till 24 % såväl 1993 som 2003. Detta gällde samtliga åldersgrupper utomåldersgruppen 40-åringar. I första hand minskade andelen rökare. Samtidigt ökade snusarna isamtliga åldersgrupper 20-60 år innebärande ett i stort sett oförändrat tobaksbruk 1993 och2003. Det förelåg ingen statistisk signifikant skillnad vid de tre undersökningsåren mellantobaksbrukare och icke/brukare med avseende på inkomst-, utbildningsnivå, civilstånd, ochKASAM poäng. År 2003 förelåg en statistisk signifikant skillnad mellan brukare och ickebrukare med avseende på frekvens av tandvårdsbesök, där tobaksbrukarna i störreutsträckning än icke brukaren, inte besökte tandvården eller besökte tandvården oregelbundet.Icke brukarna borstade tänderna statistiskt signifikant oftare än tobaksbrukarna år 1993 ochicke brukarna använde tandstickor statistiskt signifikant oftare än tobaksbrukarna år 1983 och2003.

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Denna historieuppsats (15hp) handlar om aga- och skoldisciplinsfrågorna i den svenska folkskolan. Undersökningens syfte är att granska hur disciplinsfrågorna i folkskolan hanterades före och efter agaförbudet på både nationell och lokal nivå. För att uppnå detta mål har i första hand tre olika källor använts, nämligen 1947 års skoldisciplinutredning, protokoll från Tunabygdens lärarklubb och dess studiecirkel samt Skolöverstyrelsens anvisningar till folkskolelärarna efter att agan hade förbjudits i folkskolan. Skoldisciplinutredningen kom som en följd av protesterna från lärarkåren och Skolöverstyrelsen till ett agaförbud. Disciplinutredningen kom inte fram till något agaförbud utan snarare fram till flera disciplinsfrämjande förslag. I Tunabygdens lärarklubb och dess studiecirkel bedrevs diskussioner som berörde aga, disciplin och fostran överhuvudtaget. Lärarklubben och folkskolestyrelserna i landet var emot ett agaförbud, men inte enbart för rätten i sig att få aga elever, utan också för att de var emot en stark centralstyrning som de upplevde fanns och som ifrågasatte lärarnas yrkesprofession. Skolöverstyrelsens anvisningar kom 1959, året efter agaförbudet och den handlade mycket om skolans och lärarnas fostrande uppgifter. Fungerande disciplin i klassen ansågs vara lika viktig som innan agaförbudet och det handlade om att ändra formerna för denna disciplin. För att upprätthålla ett fungerande disciplin ansåg Skolöverstyrelsen att det var oerhört viktigt att lära känna igen skolbarnet och dess hemförhållanden. För att kontrollera detta hade bl.a. lärare och skolläkare viktiga roller i hemmens hjälp att fostra barnen rätt, då tilltron till barnens föräldrar och uppväxtmiljö var låg från Skolöverstyrelsens sida.