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- Dahl, Ingolf, 1950
(författare)
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Ferroelectricity, SSFLC, bistability and all that
- 2002
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Ingår i: arXiv.org.
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- In the book “Ferroelectric and Antiferroelectric Liquid Crystals” by S. T. Lagerwall, the concept “polar liquid crystals” is proposed for the concept earlier known as “ferroelectric liquid crystals”, reserving the word “ferroelectric liquid crystals” for the case of “surface stabilization”. Thus Lagerwall in this way, by redefinition, becomes the coinventor of “ferroelectric liquid crystals”. The trouble is that a closer look on the invention reveals a state of bad logic and a total confusion. The concepts “polar”, “ferroelectric”, “hysteresis”, “SSFLC” and “bistability” are essential in the writing of Lagerwall, but these words are not used in a rigorous way. Also the pictorial evidence used by Lagerwall to illustrate the discovery of surface stabilized liquid crystals raises several questions. An alternative view of the physics of SSFLC cells is presented.
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| 2. |
- Lindblom, David, et al.
(författare)
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In-situ neutron imaging of delayed hydrogen cracking in highstrength steel - experiments and modeling
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- Hydrogen delayed fracture, also known as hydrogen-induced cracking, is a type of brittle fracture that occurs due to the slow diffusion and accumulation of hydrogen atoms, leading todecreased ductility and eventual cracking under constant load. This paper presents an in-situobservation, using neutron imaging, of delayed crack propagation caused by hydrogen embrittlement in a high strength martensitic steel specimen. The experiments involved mechanicalloading of a single-edge-notch bend specimen while submerged in an electrolyte solution (H2O+ 3.5% NaCl) under cathodic polarization to facilitate hydrogen ingress. Neutron transmission images were obtained in-situ and used to monitor intermittent crack propagation wasrecorded over a period of 12 hours. The stress state at each crack configuration was extracted from a three-dimensional elastic-plastic finite element simulation, which was tailoredto match the quantitative information acquired from the neutron radiographs of the fractureprocess. To gain insight into the evolution of hydrogen concentration with crack propagation,a modeling scheme for stress-assisted hydrogen diffusion was employed. These simulationsprovided qualitative information on the relation between intermittent crack propagation andthe subsequent supply of hydrogen to the crack tip. Finally, a failure locus was constructedbased on the calculated hydrogen concentration levels and the experimentally determinedcrack growth resistance.
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| 4. |
- Eriksson, Kristina M., 1976-
(författare)
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“Book Review –Scheduling algorithms – Author: Brucker, Peter”.
- 2004
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Ingår i: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture. - 0954-4054 .- 2041-2975. ; 218:B12, s. 1845-1845
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Recension (övrigt vetenskapligt/konstnärligt)
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