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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

Multifunctional composite interphase

Zhang, Jie 12 June 2012 (has links) (PDF)
In this work, carbon nanotubes were deposited onto the insulative glass fibre surface to form a semiconductive network. Utilizing the unique properties of CNTs network, a multifunctional composite interphase could be achieved. The interfacial adhesion strength was improved by CNTs distributed in the interphase. The semiconductive interphase have been used as a chemical/phaysical sensor, strain sensor and microswitch.
2

Multifunctional composite interphase

Zhang, Jie 05 June 2012 (has links)
In this work, carbon nanotubes were deposited onto the insulative glass fibre surface to form a semiconductive network. Utilizing the unique properties of CNTs network, a multifunctional composite interphase could be achieved. The interfacial adhesion strength was improved by CNTs distributed in the interphase. The semiconductive interphase have been used as a chemical/phaysical sensor, strain sensor and microswitch.
3

Skyfallens hot mot Mälarens ekosystem / The effects of high precipitation on phosphorus transport in three tributaries to Lake Mälaren, Sweden

Immo, Nelly January 2024 (has links)
Hälsosamma ekosystem försörjer oss med livsviktiga resurser och tjänster – ekosystemtjänster så som skydd mot översvämning. I Norra Östersjöns vattendistrikt, som Mälaren tillhör, är statusen på den ekosystemtjänsten dålig. Detta beror till stor del på en omfattande dikning och brist på svämplan i området. Under perioder med skyfall riskerar därför området runt Mälaren och dess tillrinnande vattendrag att drabbas av översvämningar som skadar matproduktion, infrastruktur och miljö. Övergödning är redan ett problem i området och stora tillskott av fosfor till följd av översvämmade jordbruksmarker kan orsaka stora algblomningar och försämrad livsmiljö för vattenlevande organismer. Under augusti och september 2023 föll ovanligt stora mängder regn över mellersta Sverige vilket ökade vattenföringen i vattendragen runt Mälaren och översvämmade vissa av dem. Högfrekventa turbiditetsmätningar från in-situ sensorer installerade i Sagån, Hågaån och Fyrisån, tre vattendrag i Mälarens avrinningsområde, har använts för att undersöka skyfallens effekter på deras vattenföring och beräknad fosfortransport. Resultaten visade en signifikant korrelation mellan ökad vattenföring och ökad fosfortransport, en signifikant ökning under 2023 jämfört med 2018–2022 och signifikanta skillnader mellan vattendragen. Översvämmade Sagån hade extremt höga toppar i beräknad fosfortransport. Resultaten indikerar att övergödningsproblemen i Mälaren kan förvärras i ett framtida klimat med mer intensiva skyfall om inte åtgärder tas för att stärka avrinningsområdets förmåga att hantera stora mängder nederbörd. / Healthy ecosystems provide us with vital resources and services – ecosystem services such as flood protection. In the North Baltic Sea Water District, to which Lake Mälaren belongs, the status of that ecosystem service is poor, largely as a result of extensive draining in the area leading to a lack of floodplains. During periods of torrential rain, the area around Lake Mälaren and its tributaries is therefore at risk to be affected by floods that cause damage to food production, infrastructure and the environment. Eutrophication is already a problem in the area and large additions of phosphorus as a result of flooded agricultural land can cause large algal blooms and degraded habitat for aquatic organisms. During August and September 2023, unusually large amounts of rain fell over central Sweden, which increased the flow of water in Lake Mälarens tributaries and flooded some of them. High frequency turbidity data from in-situ sensors installed in Sagån, Hågaån and Fyrisån, three tributaries to Lake Mälaren, was used to study the effects of the heavy rains on their waterflow and estimated phosphorus transport. The results showed a significant correlation between increased water flow and increased phosphorus transport, a significant increase in 2023 compared to 2018-2022 and significant differences between the tributaries. Flooded Sagån had extremely high peaks in estimated phosphorus transport. The results indicate that the eutrophication problems in Lake Mälaren may worsen in a future climate with more intense downpours unless measures are taken to strengthen the catchment's ability to handle large amounts of rainfall.
4

Multifunctional components from carbon concrete composite C³ – integrated, textile-based sensor solutions for in situ structural monitoring of adaptive building envelopes

Haentzsche, Eric, Frauendorf, Moritz, Cherif, Chokri, Nocke, Andreas, Reichardt, Michaela, Butler, Marko, Mechtcherine, Viktor 05 November 2019 (has links)
This contribution will introduce carbon-reinforced concrete components (so-called carbon concrete composites, or C³) with sensor functionalities for innovative building envelopes. For a continuous in situ structural monitoring, these textile-reinforced concrete components are equipped with textile sensor networks consisting of resistive carbon fiber sensors (CFSs), which are integrated into the carbon fiber non-crimp fabrics of the concrete reinforcement by multiaxial warp-knitting. The in situ CFSs, consisting of 1 k or 50 k carbon fiber roving with added staple fiber/multifilament dielectric cladding, are later integral to the load-distributing elements of the concrete component, and elongations within these are easy to record with good correlation to ohmic resistance changes. Gage factors of k = 0.52–1.23 at linearity deviations of ALin=4.0–8.7% are feasible. This allows a monitoring of C³ building envelopes for structural mechanical changes caused by physical changes within the component through mechanical or thermal loads or deformation and cracks.

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