827 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
Snow cover fraction on land fromt MODIS at the three GEM sites
No full textSnow cover fraction on ground from MODIS.
Gaps due to cloud cover are filled using the last available observation. A description paper is in preparation.Please contact the author directly with any questions
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
Promotion of phonemic phonological perception for 5 – 6 years old children with phonological disorders by using natural materials
No full textDiplomdarba nosaukums: “Fonemātiskās uztveres sekmēšana 5 – 6 gadus veciem bērniem ar fonētiski fonemātiskiem traucējumiem, izmantojot dabas materiālus” Darba autore: Signe Jonase Darba zinātniskā vadītāja: Mg. paed. Egija Laganovska Darba saturs: 61 lapas, 7 attēli, 7 tabulas, 4 pielikumi. Pētījuma mērķis: Teorētiski izpētīt un praktiski pārbaudīt dabas materiālu izmantošanas efektivitāti 5 – 6 gadus veciem bērniem ar fonētiski fonemātiskiem traucējumiem. Pētījuma teorētiskajā daļā tiek analizēta dažādu autoru zinātniskā literatūra. Darba autore apraksta bērnu attīstību kopveselumā (fizisko, emocionālo, kognitīvo un sociālo), fonemātiskā uztvere, tās traucējumi un attīstīšanas paņēmieni. Pētījuma empīriskajā daļā autore apraksta pētnieciski praktisko darbību (novērošanu, runas pārbaudi, anketēšanu), balstoties uz teorētiskajā daļā gūtajām atziņām, kā arī, veic iegūto rezultātu analīzi. Pētījuma rezultātā iegūtie dati tiek apkopoti tabulās un attēlos. Darba noslēgumā tiek izdarīti secinājumi un sniegti ieteikumi vecākiem un pedagogiem. Atslēgas vārdi: logopēdija, runa, valoda, attīstība, skaņu izrunas traucējumi, fonemātiskās uztvere, fonemātiskās uztveres traucējumi, dabas materiāli.Title of graduation work: “Promotion of phonemic phonological perception for 5 – 6 years old children with phonological disorders by using natural materials” Author: Signe Jonase Supervisor: Mg. paed. Egija Laganovska Structure: 61 pages, 7 pictures, 7 tables, 4 attachments Reserch goal: In theory, study and practice the effectiveness of the use of natural materials for children 5 to 6 years old with phonetic phonetic phonemic disorders. The theoretical part of the study analyses the scientific literature of the authors. The author of the work describes the development of children in general (physical, emotional, cognitive and social), phonographic perception, its disorders and development techniques. In the empirical part of the study, the author describes the practice of research (observation, speech testing, anketting), based on the lessons learned from the theoretical part, as well as an analysis of the results obtained. The resulting data from the study is collected in tables and images. The work concludes by drawing conclusions and making recommendations to parents and teachers. Key words: speech therapy, speech, language, development, phonetic disorders, phonetic perception, phonetic perception disorders, natural material
Possibilities of electricity production development in Latvia
No full textLatvija ir viena no ES līderēm atjaunojamo energoresursu izmantošanā elektroenerģijas ražošanā, tomēr vēja potenciāls Latvijā nav apgūts.
Maģistra darba Elektroenerģijas ražošanas attīstības iespējas Latvijā autore Signe Allena izvirzījusi mērķi izvērtēt vēja enerģijas izmantošanas potenciālu Rīgas Tehniskajā universitātē, uzstādot mazās vēja turbīnas. Galvenie uzdevumi mērķa īstenošanai ir analizēt zinātniskās publikācijas un praktisko pieredzi, apkopot vēja mērījumus, noteikt vēja turbīnu iespējamo saražotās elektroenerģijas apjomu, izstrādāt elektroenerģijas cenu scenārijus, izvērtēt atmaksāšanās periodus turbīnu uzstādīšanai un noteikt ekonomiski izdevīgāko vēja turbīnu modeli.
Maģistra darba rezultātā ir izvērtēts vēja enerģijas potenciāls un novērtēts ekonomiskais izdevīgums vēja turbīnu uzstādīšanai Rīgas Tehniskajā universitātē.
Atslēgvārdi: elektroenerģijas ražošana, vēja enerģija, statistiskā analīzeLatvia are one of the leading countries in renewable energy usage in electricity generation at EU level, however wind potential is still unfulfilled.
Author Signe Allena of master thesis Possibilities of electricity production development in Latvia aims to assess the wind energy potentional installing small wind turbines at Riga Technical University. The main tasks are to analyze scientific publications and practical experience, gather wind measurements, determine the potentional electricity amount generated by wind turbines, develop electricity price scenarios, evaluate financial return periods of turbine installation and identify the most economically attractive wind turbine model.
As a result of the master thesis the potential of wind energy has been identified and economic advantage of turbine installation at Riga Technical University has been assessed.
Keywords: power generation, wind power, statistical analysi
Work environment risks in metalworking industry and prevention measures
No full text“Metālapstrādē nodarbināto darba vides riski un to novēršanas pasākumi”. Darba autore Signe Vējkrīgere. Darba zinātniskā vadītāja: asoc. profesore, Dr. med. Ženija Roja. Maģistra darbs sastāv no 4 nodaļām, secinājumiem un praktiskajām rekomendācijām. Pirmajā nodaļā literatūras avotos publicētā informācija par metālapstrādes nozarē sastopamajiem darba vides riska faktoriem, to cēloņiem un ietekmi uz nodarbināto veselību. Otrajā daļā aprakstītas darbā izmantotās risku novērtēšanas metodes, bet trešajā daļā – apkopoti un analizēti pētījuma rezultāti. Ceturtā nodaļa ir vadlīnijas veselīgas un drošas darba vides nodrošināšanai metālapstrādē nodarbinātajiem, iekļaujot risku novēršanas un samazināšanas pasākumus nozarē. Darba apjoms ir 76 lpp., satur 21 attēlu, 12 tabulas, 12 pielikumus, izmantots 51 literatūras avots. Darbs uzrakstīts latviešu valodā. Atslēgvārdi: Darba vide, analīze, vadlīnijas, metālapstrāde“Work environment risks in metalworking industry and prevention measures”. Author: Signe Vējkrīgere. Scientific advisor: asoc. prof., Dr. med. Ženija Roja. Master’s thesis consists of four sections, conclusions. The first section analyzes published information from literature sources on occupational risk factors, their causes and impact on employees health in metalworking industry. The second section describes risk assessment methods, that are used in this thesis, but the third section – summary and analysis of results. Fourth section is guidelines how to provide safe and healthy work environment for metalworking industry’s employees, which includes occupational risk reduction and prevention measures. Master’s thesis contain 76 pages, including 21 figures, 12 tables, 51 literature references, 12 appendices. Thesis is written in Latvian. Keywords: Work environment, analysis, guidelines, metalworking
Awareness raising of ecological lifestyle for children of older preschool age
No full textTemats – Ekoloģiska dzīvesveida izpratnes pilnveide vecākajā pirmsskolas vecumā Darba autore – Signe Sokova Darba vadītāja – Dr. Psych. Tija Zīriņa Pētījuma mērķis – pētīt ekoloģiska dzīvesveida izpratnes pilnveidi vecākā pirmsskolas vecuma bērniem mācību jomu centros. Darbs sastāv no teorētiskās un empīriskās daļas. Teorētiskajā daļā, analizējot V. Zelmeņa, G. Svences un citu latviešu un ārzemju psihologu un pedagogu darbus, izpētīts izpratnes un ekoloģijas jēdziens. Darbā raksturots vecākā pirmsskolas vecuma bērna attīstības likumsakarības pētāmās problēmas kontekstā. Empīriskajā daļā tiek raksturoti bērni pēc viņu uzvedības īpatnībām, veikta analīze. Pētītas metodes, ar kādām sekmīgāk veidot izpratni par ekoloģiska dzīvesveida pamatprincipiem. Atslēgas vārdi: ekoloģiskais dzīvesveids, izpratne, vecākā pirmsskolas vecuma bērni, vecumposmu likumsakarības.Research topic– Awareness raising of ecological lifestyle for children of older preschool age Author – Signe Sokova Supervisor – Dr. psych. Tija Zīriņa Research objective- study awareness raising improvement of ecological lifestyle for children of older preschool age in learning centers. The research consists of a theoretical and an empirical part. In the theoretical part, analyzing the works of V. Zemlenis, G. Svence and other Latvian and foreign psychologists and teachers, the concept of understanding and ecology is studied. The paper describes peculiarities of the oldest preschool age in the context of the research problem. In the empirical part, children are described according to their behavioral characteristics, analysis is performed. Methods for better understanding of the basic principles of ecological lifestyle have been studied. Key words: ecological lifestyle, awareness, children of the older pre-school age, peculiarities of the age period
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