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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vliv teploty na pevnost lepeného spoje nábytkových hran z jehličnatého dřeva

Picková, Michaela January 2017 (has links)
This work aims on the effect of temperature on the strength of adhesive joints of coniferous wood furniture edges. The objective of the research was to determine the difference between hot melt ethyl-vinyl-acetate (EVA) and hot melt polyurethane (PUR) adhesives. The main focus was devoted to the maximum achievable strength of bonded joints at different temperatures. The peeling test at an angle of 90 degrees and a shear pressure test at an angle of 45 degrees were performed to test the strength of joints to resist the stress. The data had been analyzed using analysis of variance (ANOVA) method to compare the strenght mean values of glues with each other. The results show that PUR glue achieves higher resistance in peel as it withstood the stress even at 70°C. The oblique shear pressure test results were however not possible to compare because of exceeding the measuring range limit of the ripping device while testing PUR adhesive samples. Based on the data it can be summarized that melt PUR adhesive for furniture edge banding is more convenient than EVA adhesive which does not reach the required strength in both types of tests conducted.
2

Ambulanssjuksköterskans upplevelse av att vårda etylpåvekade patienter i en prehospital vårdmiljö

Fagerström, Jessica, Barret, Kajsa January 2023 (has links)
Bakgrund: Den prehospitala miljön är en komplex och mångfacetterad miljö där ambulanssjuksköterskan inte bara ställs inför olika kliniska svårighet, utan också av ett brett spektrum av sociala, miljömässiga och logistiska utmaningar. Etylpåverkade patienter försvårar patientbedömningen och gör situationen svår och mer komplex. Etylpåverkan och den offentliga miljön är även förknippad med ökad risk för hot och våld, både för ambulanssjuksköterskan men också för den utsatta etylpåverkade patienten. Detta bidrar till att ambulanssjuksköterskan utsätts för svåra patientbedömningar men även känslomässigt och psykiskt påfrestande situationer. Syfte: Syftet med studien är att utforska ambulanssjuksköterskans upplevelser av att vårda etylpåverkade patienter i en prehospital vårdmiljö Metod: En intervjustudie genomfördes genomenskilda intervjuer med tio ambulanssjuksköterskor inom Västra Götalandsregionen. Data analyserades med hjälp utav en kvalitativ innehållsanalys med induktiv ansats. Resultat: Analysen resulterade i 4 kategorier som bildade resultatets huvudrubriker “kunskap”, “vårdinstanser”, “etiska utmaningar” samt “arbetsmiljöns påverkan på mötet”. Slutsats: Genom denna studie kan kunskapsbidraget generera ökad förståelse för ambulanssjuksköterskors upplevelse av att vårda etylpåverkade patienter i en prehospitalmiljö. Studien kan även bidra till bättre förståelse för ambulanssjuksköterskans behov av vidare utbildning i ämnet för att öka den egna erfarenheten. Genom ökad förståelse och stöd för ambulanssjuksköterskor vid omvårdnad av etylpåverkade patienter möjliggörs en högre patientsäkerhet.
3

Structural Characterization and Quantitative Analysis by Interfacing Liquid Chromatography and/or Ion Mobility Separation with Multi-Dimensional Mass Spectrometry

Solak, Nilüfer 21 May 2010 (has links)
No description available.
4

\"Fotoluminescência excitada no ultravioleta em polímeros conjugados\" / Photoluminescence excited in the ultraviolet in conjugated polymers

Marcelo Meira Faleiros 13 February 2007 (has links)
Os polímeros conjugados luminescentes são materiais com grande potencial tecnológico, mas apesar de estudados desde a década de 80, algumas de suas propriedades óticas ainda não foram totalmente entendidas. Por exemplo, ainda persistem dúvidas quanto à natureza das suas excitações primárias. Nesse sentido foi feito um estudo da fotoluminescência do poli[2-metoxy-5-(2-etil-hexiloxi)-1,4-fenileno vinileno] (MEH-PPV), polímero semicondutor luminescente cujas propriedades ópticas já foram muito investigadas. Além da banda de absorção principal na região visível do espectro, ele possui três bandas no ultravioleta. O objetivo deste trabalho é investigar a fotoluminescência do MEH-PPV quando excitado na região do ultravioleta. Após fotoexcitação no ultravioleta, observou-se apenas a fotoluminescência usual no visível. A intensidade da emissão depende fortemente da energia de excitação, da temperatura e da estrutura morfológica do sistema polimérico, determinada pelo método de preparação das amostras. Os resultados indicam que os estados excitados no ultravioleta relaxam rapidamente de forma não-radiativa até os estados de menor energia, de onde então ocorre a luminescência. Entretanto, a eficiência da fotoluminescência excitada no ultravioleta é consideravelmente reduzida, indicando que a excitação a altas energias abre novos canais de relaxação não-radiativos. / Luminescent semiconducting polymers are technological promising materials, but although studied since the 80’s some of their optical properties have not yet been fully understood. For instance, the nature of their primary excitations is still on debate. Therefore we proposed to study the photoluminescence following photoexcitation in the ultraviolet of the polymer poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV). It is a semiconducting luminescent polymer with a main absorption band in the visible part of the spectrum, but with three other absorption bands in the ultraviolet. After ultraviolet photoexcitation it was observed only the usual visible photoluminescence. The intensity of photoluminescence depends strongly on temperature, excitation wavelength and morphological structure of the polymer, determined by the method of sample preparation. The results show that by ultraviolet excitation the excited states relax rapidly non-radiatively to the lower energy states, from where luminescence results. However, the photoluminescence efficiency with ultraviolet photoexcitation is considerably reduced, implying that the highly excited states in the polymer have more non-radiative relaxation channels available.
5

\"Fotoluminescência excitada no ultravioleta em polímeros conjugados\" / Photoluminescence excited in the ultraviolet in conjugated polymers

Faleiros, Marcelo Meira 13 February 2007 (has links)
Os polímeros conjugados luminescentes são materiais com grande potencial tecnológico, mas apesar de estudados desde a década de 80, algumas de suas propriedades óticas ainda não foram totalmente entendidas. Por exemplo, ainda persistem dúvidas quanto à natureza das suas excitações primárias. Nesse sentido foi feito um estudo da fotoluminescência do poli[2-metoxy-5-(2-etil-hexiloxi)-1,4-fenileno vinileno] (MEH-PPV), polímero semicondutor luminescente cujas propriedades ópticas já foram muito investigadas. Além da banda de absorção principal na região visível do espectro, ele possui três bandas no ultravioleta. O objetivo deste trabalho é investigar a fotoluminescência do MEH-PPV quando excitado na região do ultravioleta. Após fotoexcitação no ultravioleta, observou-se apenas a fotoluminescência usual no visível. A intensidade da emissão depende fortemente da energia de excitação, da temperatura e da estrutura morfológica do sistema polimérico, determinada pelo método de preparação das amostras. Os resultados indicam que os estados excitados no ultravioleta relaxam rapidamente de forma não-radiativa até os estados de menor energia, de onde então ocorre a luminescência. Entretanto, a eficiência da fotoluminescência excitada no ultravioleta é consideravelmente reduzida, indicando que a excitação a altas energias abre novos canais de relaxação não-radiativos. / Luminescent semiconducting polymers are technological promising materials, but although studied since the 80’s some of their optical properties have not yet been fully understood. For instance, the nature of their primary excitations is still on debate. Therefore we proposed to study the photoluminescence following photoexcitation in the ultraviolet of the polymer poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV). It is a semiconducting luminescent polymer with a main absorption band in the visible part of the spectrum, but with three other absorption bands in the ultraviolet. After ultraviolet photoexcitation it was observed only the usual visible photoluminescence. The intensity of photoluminescence depends strongly on temperature, excitation wavelength and morphological structure of the polymer, determined by the method of sample preparation. The results show that by ultraviolet excitation the excited states relax rapidly non-radiatively to the lower energy states, from where luminescence results. However, the photoluminescence efficiency with ultraviolet photoexcitation is considerably reduced, implying that the highly excited states in the polymer have more non-radiative relaxation channels available.
6

Nové gelové elektrolyty / New gel electrolytes

Sumka, Martin January 2016 (has links)
This master´s thesis deals with the properties of gel polymer electrolytes, brief characteristics of other types of electrolytes and materials that are used for preparing polymer electrolytes. The thesis explains the use of the gel electrolytes in practice, the current conduction in the electrolytes and the properties of ionic liquids, and flame retardants. This thesis also focuses on methods of measurement of mechanical properties of gel polymer electrolytes. The practical part is focused on preparation of methacrylate gel electrolytes and their modifications with the use of flame retardant - triethyl phosphate (TEP) and ionic liquid - 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Emim TFSI). In this part there are evaluations of their potential funcionality (potential window) and specific conductance conductivity using the method LSV (linear sweep voltammetry) and impedance spectroscopy. The practical part also includes a thermal analysis of selected samples by TGA, DTA and EGA methods.

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