103 research outputs found
ATR-FTIR spectroscopy and quantitative multivariate analysis of paints and coating materials
No full textThe applicability of ATR-FTIR spectroscopy with partial least squares (PLS) data analysis was evaluated for quantifying the components of mixtures of paint binding media and pigments, and alkyd resins. PLS methods were created using a number of standard mixtures. Validation and measurement uncertainty estimation was carried out. Binary, ternary and quaternary mixtures of several common binding media and pigments were quantified, with standard measurement uncertainties in most cases below 3g/100g. Classes of components - aromatic anhydrides and alcohols - used in alkyd resin synthesis were also successfully quantified, with standard uncertainties in the range of 2-3g/100g. This is a more demanding application because in alkyd resins aromatic anhydrides and alcohols have reacted to form a polyester, and are not present in their original forms. Once a PLS method has been calibrated, analysis time and cost are significantly reduced from typical quantitative methods such as GC/MS. This is beneficial in the case of routine analysis where the components are known
Microplastics and Associated Microorganisms in the Sea Sediment of the Sentina Regional Natural Reserve (Central Adriatic Sea, Italy)
No full text(1) Background: The large dispersion of microplastics (MPs) in the marine environment has effects on the health of living organisms [1,2,3]. The aim of this study was to identify MPs and their associated microorganisms in Adriatic Sea sediments and to evaluate the antibiotic susceptibility patterns of the microbial communities. (2) Methods: A beach transect, parallel to the shoreline where the waves break, was identified for the samplings. A protocol to perform MP isolation from sandy sediments at different seasons, suitable for biological sample upkeeping, and based on plastic floating in high salinity water, was optimized. From floating MPs, aerobic and anaerobic cultivable microorganisms were isolated and total DNA extraction was performed for the shotgun metagenomic analysis. Susceptibility to a panel of 14 antibiotics, belonging to 12 different categories, was assessed [4,5]. Chemical characteristics of the isolated MPs were analysed using a Thermo Nicolet 6700 FT-IR Spectrometer with “Smart Orbit” diamond micro-ATR accessory and Thermo Nicolet iN10 MX FT-IR microscope. (3) Results: Via chemical analysis, polypropylene microplastics were estimated in the highest percentage, followed by polyethylene, poly-methyl acrylate, and poly-vinyl chloride. Metagenomics data revealed differences in bacterial abundances during seasons and in floating MPs with respect to total sand. The differential gene analysis showed specific metabolic pathways in MP-associated microorganisms, including antibiotic resistance. Via microbial cultivation and MALDI-TOF MS identification, bacteria that are promising for plastic degradation, such as Lysinobacillus fusiformis, Exiguobacterium sp., and Pseudomonas oleovorans, were also found, as well as potential pathogens, like Clostridium septicum, Clostridium novyi, and Shewanella putrefaciens. Only 17.2% were found to be susceptible to all the tested antibiotics. High percentages of resistance were observed for penicillins (85.7%), monobactams (80.9%), and tetracyclines (64.3%). (4) Conclusions: MPs work as a vehicle for potential pathogens and antibiotic-resistant microorganisms in the Central Adriatic Sea
ATR-FT-IR spektroskoopia võimaluste laiendamine anorgaaniliste pigmentide analüüsimisel
No full textVäitekirja elektroonilisest versioonist puuduvad publikatsioonide täistekstid.The present work focused on expanding the possibilities and usefulness of micro-ATR-FT-IR spectroscopy in identification of different inorganic pigments in historic artefacts.
Most of the pigments used historically in paintings and other artefacts are inorganic compounds. ATR-FT-IR has found limited use for determination of inorganic pigments, because the mid-IR (4000–400 cm–1) region of the IR spectrum of many of them is not characteristic enough and also there are many pigments that either do not absorb in that region at all (oxides, sulphides, etc) or have absorptions that are at the low wavenumber end of that region and are not characteristic enough for pigment identification. So, many pigment materials absorb IR radiation in the far-IR region (below 500 cm–1). In contrast to the mid-IR region the far-IR region has traditionally been significantly less accessible for routine IR spectroscopic measurements. However, recent advances in instrument design have brought the wavenumber range below 500 cm–1 well within reach of commercial FT-IR equipment. Nevertheless, this wavenumber region has up to now found almost no use in investigation of historic artefacts.
In this dissertation 47 most widespread inorganic red, white, yellow, blue, green, brown and black pigments were examined. An analytical method for determination and identification of these inorganic pigments in paint layers by micro-ATR-FT-IR using the wavenumber region of 550–230 cm–1 was developed. The advantages and limitations of the ATR-FT-IR and developed analytical method of the analysis of inorganic pigments in the low wavenumber were discussed.
This work provides a comprehensive overview of the inorganic pigment identification possibilities using ATR-FT-IR as well as a collection of reference spectra in the low wavenumber range (550-230 cm-1) and is expected to be a useful reference material for conservation practitioners and material scientists. The usefulness of ATR-FT-IR in the region of 550-230 cm-1 for identification of inorganic pigments is demonstrated by 5 case studies on art objects (several of them are important in Estonian history).Käesolevas doktoritöös keskenduti mikro-ATR-FT-IR spektroskoopia võimaluste hindamisele ja rakendusala laiendamisele erinevate anorgaaniliste pigmentide uurimisel.
Sajandeid on erinevate maalide maalimisel ja teiste kunstiobjektide kaunistamisel kasutatud värvi koostises anorgaanilisi pigmente. FT-IR spektroskoopiat on piiratult kasutatud anorgaaniliste pigmentide analüüsimisel kuna IR spektris kesk-IR ala (4000–400 cm–1) pole mitmete pigmentide määramisel küllalt karakteristlik, samuti on palju selliseid pigmente, mis ei neela üldse selles alas (oksiidid, sulfiidid) või omavad neeldumisi, mis on keskmise IR ala lõpus ja need ei ole küllalt karakteristlikud pigmendi tuvastamisel seguproovis. On teada, et paljud pigmendid neelavad kaug-IR piirkonnas (allpool 500 cm-1). Varem, kasutades tavalisi FT-IR spektromeetreid, oli võrreldes kesk-IR alaga kaug-IR alas mõõtmisi palju raskem teostada. Tänapäeval uuemad FT-IR seadmed võimaldavad kasutada lainearvude piirkonda allpool 500 cm-1. Hoolimata sellest seda piirkonda kunstiobjektide uurimisel pole praktiliselt üldse kasutatud.
Käesolevas doktoritöös uuriti 47 valget, kollast, punast, sinist, rohelist, pruuni ja musta pigmenti. Töötati välja metoodika värvikihtides pigmentide analüüsimiseks mikro-ATR-FTIR meetodil kasutades lainearvude vahemikku 550–230 cm–1. Toodi välja ATR-FT-IR spektroskoopia ja väljatöötatud metoodika eelised ja puudused anorgaaniliste pigmentide uurimisel madalatel lainearvudel.
Doktoritöö annab ülevaate anorgaaniliste pigmentide uurimise võimalustest ATR-FT-IR-iga, samuti võrdlusspektrite kogumiku pigmentidest, mis neelavad madalatel lainearvudel (550–230 cm–1). Viie rakendusnäite põhjal demonstreeriti ATR-FTIR meetodi kasulikkust tuvastada värviproovides pigmenti kasutades lainearvude piirkonda 550-230 cm-1. Rakendusnäidete värviproovid võeti kunstiobjektidelt, millest mitmed on Eesti kunstiajaloos olulisel kohal
Orgaanilised-anorgaanilised interaktsioonid eksperimentaalses ja arheoloogilises keraamikas
No full textVäitekirja elektrooniline versioon ei sisalda publikatsiooneArheoloogiline savinõud on head orgaaniliste jääkide reservuaarid, mida saab kasutada algsete orgaaniliste komponentide tuvastamiseks. Selle keemilise teabe põhjal saab teavet mineviku kogukondade toitumise, tehnoloogiate, kaubandusvõrgustike ja elatusviiside kohta. Sedatüüpi analüüse nimetatakse orgaaniliste jääkide analüüsiks, mis kasutab savimaterjalis sisalduvate orgaaniliste jääkide tuvastamiseks ja kvantifitseerimiseks erinevaid analüütilise keemia meetodeid.
Vaatamata märkimisväärsetele edusammudele orgaaniliste jääkide analüüsil arheoloogilisest materjalist , on nende molekulide savimaatriksis säilimise aluseks olevad füüsikaliskeemilised mehhanismid endiselt halvasti uuritud. Teadaolevalt mõjutavad orgaaniliste molekulide säilimist kaks peamist tegurit: orgaaniliste ühendite adsorptsioon savi pooridesse, mis kaitseb neid tõhusalt keskkonnatingimuste eest , ning mineraalsete komponentide roll orgaaniliste molekulide säilimiseks savikeraamikas.
Käesolev doktoritöö annab aluse mõistmaks, kuidas savide mineraalne koostis mõjutab mikro- ja mesopooride teket. Nende interaktsioonide tuvastamiseks kasutati eksperimentaalselt loodud savibrikette, mis koosnevad erinevate savitüüpide segudest, savilisanditest ja on põletatud erinevatel temperatuuridel. Valikut neist kasutati jätkuanalüüsis, analüüsimaks, kuivõrd sõltub konkreetsete rasvhapete (C16:0 ja C18:1) tuvastamise savimaatrikis koostisest ja füüsikalistest omadustest. Gaasikromatograaf-massispektromeetria (GC-MS) kvantitatiivsed analüüsid näitasid, et savi põletustemperatuur ja rasvhapete lagunemine kuumutamisel mõjutavad oluliselt rasvhapete säilimist ja ekstraheerimistõhusust savimaatriksist. Lisaks kasutati savi mineraalsete komponentide kvantifitseerimiseksnõrgendatud täielik sisepeegeldusega Fourier' teisenduse infrapuna (ATR-FT-IR).
Neid analüüsimeetodeid kasutati Kukruse (Essti) 12.–13. sajandi matmispaiga arheoloogilise keraamika analüüsiks. Tuvastati, et eksperimentaalse materjali põhjal tuvastatud tendentsid olid kooskõlas savinõudest saadud tulemustega, mis tõestab, et mineraloogiline koostis mõjutab oluliselt lipiidide säilivist ja tuvastamist (arheoloogilisest) savimaterjalist.Archaeological pottery is a good reservoir of organic residues, that can be used to trace the original parent molecules from which these residues originated. Based on this chemical information, key archaeological questions about the diets of past communities, their technological practices, trade networks, and survival strategies can be answered. Chemical information can be obtained from pottery through a method called organic residue analysis, which employs various analytical chemistry techniques to identify and quantify organic residues in the material.
Despite significant progress in identifying organic residues in archaeological pottery over the years, the mechanism underlying the retention of these molecules within the clay matrix remains poorly understood. Two primary factors are known to influence this retention: the adsorption of organic compounds within the pores of clay, which effectively shields them from the harsh environmental conditions during burial, thus preserving them, and the role of the minerals in the clay pottery itself.
The contribution of this doctoral thesis provides baseline quantitative data on how mineral composition of clays influences the formation of micro- and mesopores. This was achieved through the use of experimental replicate clay briquettes made from mixtures of different clay types, temper, and fired at different temperatures. Some of these briquettes were tested for the recovery of simple fatty acids (C16:0 and C18:1). Quantitative analysis with gas chromatography-mass spectrometry (GC-MS) proved that the temper and degradation by heating significantly affect its recovery. Furthermore, an alternative method for quantifying mineral components in clays using attenuated total reflection Fourier transform infrared (ATR-FT-IR) was also employed.
These findings were applied to archeological pottery from a 12th to 13th century AD burial site at Kukruse, Estonia, and found to be consistent with the results of the clay briquettes, proving that the mineralogical composition greatly affects the recovery of lipids.https://www.ester.ee/record=b572961
Analysis of harvester working time for example Ponsse Ergo
No full textTöö koosneb kolmest petaükist. Esimeses peatükis kirjeldatakse harvesteri ehituslikku poolt ning raietehnoloogiat. Teine peatükk materjalist ja metoodikast annab ülevaate uuritud harvesterist, masina operaatorist, töös uuritud raielankidest ning sellest, kuidas kogu uurimus läbi viidi. Töö kolmandas peatükis kajastatakse uurimuse käigus saadud tulemusi ning võrreldakse neid mõningate varasemalt läbi viidud uurimuste tulemustega.
Antud töö on valminud põhiliselt autori vaatluse ja analüüsi põhjal. Vaatlused toimusid raielankidel, videokaamerat kasutades ning hiljem filmitut arvutis analüüsides. Materjali filmiti kokku ca. 17 tundi. Lisaks filmimisele pani autor kirja märkmeid harvesteri tööd raskendavatest teguritest ning operaatori tähelepanekuid.
Autori arvates saavad antud tööst kasu nii harvesteri operaatorid kui ka harvestere omavad ettevõtted. Tööst saab teadmisi tulevikus metsamasinatel töötamisel või nende töö organiseerimisel ka autor.The work cosists of three parts, the first chapter describes the constructional side of the harvester, and short overview of the harvester harvesting technology. The second chapter material and methods, describes studied harvester, harvester operator, cutting areas and how all research was conducted. The thrid chapter gives overview working time in clear cutting and thinning areas and a reference to previous similar studies.
Work is based on the author´s observation and analysis. Observations were in the forest by using videocamera and later data was analyzed in computer. The material was filmed about 17 hours. Author wrote notes about hindrances of harvester work and operator comments.
Author think´s that work gives benefits for harvester operators and harvester holding companies. Work gives author knowledge about future working on harvester or organizing harvester work
Õlivärvides sideaine määramine GC-MS meetodil
No full textKäesolevas magistritöös töötati välja metoodikad õlivärvi sideaine analüüsimiseks GC-MS-iga. Proovi derivatiseerimiseks kasutati kolme meetodit (TMTFTH, NaOEt koos BSTFA-ga, happekatalüütiline metüleerimine), millele leiti derivatiseerimisefektiivsused. Kvalitatiivses analüüsis viidi läbi linaseemneõli vanandamisseeria, kus leiti sobivaim derivatiseerimisreagent õli komponentide identifitseerimiseks nii värskes kui ka vananenud õlis. Töötati välja kvantitatiivse analüüsimetoodika õli peamiste rasvhapete sisalduste määramiseks ning loodi rutiinmeetod õlivärvide sideaine määramiseks. Metoodikaid kasutati reaalsete värviproovide analüüsis. Käesolevas töös välja töötatud metoodikaid on tulevikus võimalik rakendada ka teiste traditsiooniliste õlide analüüsiks
Eesti barokiajastu meistri Christian Ackermanni artefaktide materjaliuuringud
No full textKäesoleva töö raames uuriti Järva-Madise kiriku altari korpust, Kristuse ja lõunapoolse ingli kuju ning Koeru kiriku krutsifiksi. Nimetatud kohtadest võetud proovidele tehti põhjalikud värviuuringud, kasutades mikroskoopilisi, SEM-EDS, ATR-FT-IR spektroskoopilisi ja mikrospektroskoopilisi meetodeid. Tulemusena tuvastati kasutatud pigmendid, täiteained ja sideained ning selle põhjal öeldi, kas objektid kuuluvad Christian Ackermanni töökoja teoste hulka
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