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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.
41

Investigation of Immersion Cooled ARM-Based Computer Clusters for Low-Cost, High-Performance Computing

Mohammed, Awaizulla Shareef 08 1900 (has links)
This study aimed to investigate performance of ARM-based computer clusters using two-phase immersion cooling approach, and demonstrate its potential benefits over the air-based natural and forced convection approaches. ARM-based clusters were created using Raspberry Pi model 2 and 3, a commodity-level, single-board computer. Immersion cooling mode utilized two types of dielectric liquids, HFE-7000 and HFE-7100. Experiments involved running benchmarking tests Sysbench high performance linpack (HPL), and the combination of both in order to quantify the key parameters of device junction temperature, frequency, execution time, computing performance, and energy consumption. Results indicated that the device core temperature has direct effects on the computing performance and energy consumption. In the reference, natural convection cooling mode, as the temperature raised, the cluster started to decease its operating frequency to save the internal cores from damage. This resulted in decline of computing performance and increase of execution time, further leading to increase of energy consumption. In more extreme cases, performance of the cluster dropped by 4X, while the energy consumption increased by 220%. This study therefore demonstrated that two-phase immersion cooling method with its near-isothermal, high heat transfer capability would enable fast, energy efficient, and reliable operation, particularly benefiting high performance computing applications where conventional air-based cooling methods would fail.
42

Pappersgarn, framtidens fiskenät? / Paper yarn, the fishing net of the future?

Alkin, Linnea, Ingerholt, Saga January 2023 (has links)
Textilindustrin är i behov av nya material som kräver mindre resurser än konventionellt använda material som exempelvis syntet- och bomull. Syntetiska material har en negativ påverkan på miljön, bland annat på grund av den mängd mikroplaster som släpps ut i naturen vid produktion och användning (Nagamine, Kobayashi, Kusumi & Wada 2022). En industri där syntetiska material ligger till grund för stora problem för marint liv är fiskeindustrin. När syntetiska nät tappas, oftast tillverkade av polyamid, fortsätter de att fånga fisk som inte tas om hand. Detta fenomen kallas spökfiske och skulle kunna motverkas om de syntetiska näten ersattes med ett naturligt biologiskt nedbrytbart material. Pappersgarn är ett relativt nytt material inom textilindustrin och har många egenskaper som är önskvärda vid användning i ett fiskenät, speciellt det faktum att det är biologiskt nedbrytbart. Denna studie undersöker möjligheten att använda ett pappersgarn i fiskeutrustning, närmare bestämt en kräftmjärde. Studien undersöker tre olika pappersgarn med olika grovlek, det vill säga Tex (92, 218 och 1814). Experiment utförs på garnets draghållfasthet och nedbrytningsförmåga. Ett test i bristningsstyrka görs på nät tillverkade av garnen. Testerna visar att garn med Tex 1814 är det mest lämpliga att använda i en kräftmjärde. Detta garn hade en draghållfasthet, efter 14 dagar i naturligt havsvatten, på 10541 centinewton/tex [cN/tex]. Nätet tillverkat av samma garn hade en genomsnittlig bristningsstyrka på 136 kilopascal [kPa], vilket var över den genomsnittliga bristningsstyrkan för ett nät i polyamid. Om syntetisk fiskeutrustning skulle ersättas med biologiskt nedbrytbart pappersgarn skulle det kunna motverka spökfiske och minska mängden mikroplaster i naturen. / The textile industry is in need of new materials that use less resources than conventionally used material such as synthetics and cotton. Furthermore, synthetic materials have a negative impact on the environment partly due to the amount of micro plastics that are released in nature during production and use (Nagamine, Kobayashi, Kusumi & Wada 2022). One area where synthetic materials are causing a lot of damage is the fishing industry. Synthetic nets that are lost or dropped keep catching fish that are not taken care of. This phenomenon is called ghost fishing and could be solved if the synthetics were replaced with a natural biodegradable material. Paper yarn is a relatively new material in the textile industry and has many properties that are preferred if used in a fishing net, especially the fact that it is biodegradable. This study investigates the possibility of using a paper yarn in fishing gear, more specifically a crayfish trap. The study examines three different paper yarns with different weight, also called Tex (92, 218 and 1814). Experiments are done on the yarn's tensile strength and degradability. A bursting strength test is made on nets made out of the yarns. The tests show that yarn with Tex 1814 is the most suitable to use in a crayfish trap. This yarn had a tensile strength, after 14 days in natural seawater, of 10541 centinewton/tex [cN/tex]. The net made of the same yarn had an average bursting strength of 136 kilopascal [kPa] which was above the average bursting strength of a polyamide net. If synthetic fishing gear would be replaced with biodegradable paper yarn, this could counteract ghost fishing and reduce micro plastics ending up in nature.
43

Caractérisation et évaluation de textiles antifongiques

Hossain, Mirza Akram 12 1900 (has links)
Hypothèse: L’impression sur textile d’une formulation de microparticules lipidiques avec un principe actif (éconazole nitrate) permet de conserver ou d’améliorer son activité pharmaceutique ex vivo et in vitro. Méthode: Une formulation de microparticules d’éconazole nitrate (ECN) a été formulée par homogénéisation à haut cisaillement, puis imprimée sur un textile LayaTM par une méthode de sérigraphie. La taille des microparticules, la température de fusion des microparticules sur textile et la teneur en éconazole du tissu ont été déterminées. La stabilité de la formulation a été suivie pendant 4 mois à 25°C avec 65% humidité résiduelle (RH). L’activité in vitro des textiles pharmaceutiques a été mesurée et comparée à la formulation commerciale 1% éconazole nitrate (w/w) sur plusieurs espèces de champignons dont le C. albicans, C. glabrata, C. kefyr, C. luminisitae, T. mentagrophytes et T. rubrum. La thermosensibilité des formulations a été étudiée par des tests de diffusion in vitro en cellules de Franz. L’absorption cutanée de l’éconazole a été évaluée ex vivo sur la peau de cochon. Résultats: Les microparticules d’éconazole avaient des tailles de 3.5±0.1 μm. La température de fusion était de 34.8°C. La thermosensibilité a été déterminée par un relargage deux fois supérieur à 32°C comparés à 22°C sur 6 heures. Les textiles ont présenté une teneur stable pendant 4 mois. Les textiles d’ECN in vitro ont démontré une activité similaire à la formulation commerciale sur toutes ii espèces de Candida testées, ainsi qu’une bonne activité contre les dermatophytes. La diffusion sur peau de cochon a démontré une accumulation supérieure dans le stratum corneum de la formulation textile par rapport à la formulation Pevaryl® à 1% ECN. La thermo-sensibilité de la formulation a permis un relargage sélectif au contact de la peau, tout en assurant une bonne conservation à température ambiante. / Hypothesis: Textile imprinted with a formulation of microparticles of a drug (econazole nitrate) can maintain or improve its pharmaceutical activity ex vivo and in vitro. Methods: A formulation of econazole nitrate microparticles was made by high shear homogenization then printed on a LayaTM textile by screen-printing. The size of microparticles, melting temperature of microparticles on textile and econazole nitrate content were determined. The stability of the formulation was followed for 4 months at 25°C with 65% residual humidity (RH). The in vitro activity of pharmaceutical textiles was measured and compared to the commercial formulation econazole nitrate 1% (w/w) in several species of fungi including C. albicans, C. glabrata, C. kefyr, C. luminisitae, T. mentagrophytes and T. rubrum. Temperature sensitivity of the formulations was studied by in vitro tests in Franz diffusion cells. Dermal absorption of econazole nitrate was assessed ex vivo on pig skin. Results: Econazole microparticles were 3.5±0.1 μm in diameter. The melting temperature was 34.8°C. The thermosensitivity of the system was determined by a release test at 32°C compared to 22°C over 6 hours. Textiles showed stable levels for 4 months (97±0.3 μg/cm2). ECN textiles on in vitro tests showed similar activity to the commercial formulation on all Candida species tested, as well as good activity against dermatophytes. Ex vivo tests on pig skin showed a higher accumulation of ECN on the stratum corneum for textile formulation as compared to the Pevaryl® iv formulation. The thermo-sensitivity of the formulation permits a selective release in contact with the skin, while ensuring good storage at room temperature.
44

Analys utav elastomerer i trikåtyger : En experimentell studie som jämför egenskaper och livslängd / Analysis of elastomers in knitted fabrics : An experimental study comparing properties and longevity

Månsson, Sanna, Ericsson, Linnéa January 2024 (has links)
I denna studie undersöks XLANCE® som ett alternativt elastiskt garn emot LYCRA®. Syftet är att jämföra egenskaper och livslängd för att kunna ersätta det etablerade garnet av elastomerer på dagens marknad. Möjligheten till kemisk återvinning och cirkulära resurser har uppvisat vara möjligt med XLANCE®, som är aktuellt för att minimera det textila avfallet av material innehållandes av flera syntetiska fibrer. Genom att konstruera XLANCE® respektive LYCRA® med PES, som huvudmaterial, visar resultateten inga markanta skillnader under ISO-standardiserade tester av elasticitet, draghållfasthet och dimensionsstabilitet både före samt efter 50 tvättar. En ersättning av elastiskt garn kan därför vara möjlig. Slutsatsen bekräftas genom litteraturstudien om att XLANCE® kan separeras ifrån PET genom en filtrering utan att smälta samman, som beskrivs vara utmaningen med spandexfibrer från LYCRA®. XLANCE® höga resistens emot värme och kemikalier möjliggör denna filtrering med glykolsyra och pyrolysoljor som kan användas på nytt. Om framtida forskning kan visa praktiska resultat för separation och kemisk återvinning av XLANCE®, kan detta bli en lösning för att åstadkomma cirkulära modeller efter långvarig användning av elastiska trikåmaterial. / In this study, XLANCE® is investigated as an alternative elastic yarn to LYCRA®. The purpose is to compare properties and longevity to be able to replace the established yarn of elastomers on today’s market. The possibility of chemical recycling and circular resources has been shown to be feasible with XLANCE®, which is relevant to minimizing textile waste of materials containing several synthetic fibers. By constructing XLANCE® and LYCRA® respectively with PES as the main material, the results show no marked differences during ISO standardized tests of elasticity, tensile strength and dimensional stability both before and after 50 washes. A substitution of elastic yarn may therefore be possible. The conclusion confirms through the literature study that XLANCE® can be separated from PET by filtration without fusing, which is described as the challenge with spandex fibers from LYCRA®. XLANCE®’s high resistance to heat and chemicals enables this filtration with glycolic acid, and pyrolysis oils that can be reused. If future research can show practical results for the separation and chemical recycling of XLANCE®, this could become a solution to achieve circular models after long-term use of elastic knitted fabrics.

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