Sökning: "micro-perforated"
Hittade 4 avhandlingar innehållade ordet micro-perforated.
1. Investigation of perforated mufflers and plates
Sammanfattning : Mufflers are used in for instance exhaust system of cars or trucks to reduce noise. Perforated pipes are one of the main components of modern mufflers. To study acoustic properties of mufflers with perforated pipe is one of the main targets of this thesis. LÄS MER
2. Studies of sound generation and propagation in flow ducts
Sammanfattning : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. LÄS MER
3. Experimental and Numerical Multi-port Eduction for Duct Acoustics
Sammanfattning : Sound generation and propagation in circular ducts for frequencies beyond the cut-on frequencies of several higher order acoustic modes is investigated. To achieve this, experimental and numerical set-ups are designed and used to research aeroacoustic interactions between in-duct components and to conceive noise mitigation strategies. LÄS MER
4. Production and application of fine fractions made of chemical pulp for enhanced paperboard strength
Sammanfattning : For all kinds of paperboard packages, the bending stiffness of the paperboard is a crucial property. In multi-ply folding boxboard (FBB) grades, this is obtained by placing different stocks in the outer and centre plies of the board. In the outer plies, a stock with a high tensile stiffness is used, typically made from refined kraft pulp fibres. LÄS MER