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| 2. |
- Andersson, Carl-Håkan, et al.
(författare)
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Fibre Handleability, Damage Formation, Dust Emission and Morphology
- 1994
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Ingår i: Composites Testing and Standardization. - 1855731878 ; , s. 625-632
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Konferensbidrag (refereegranskat)abstract
- The mechanical stress build up in fibre handling, the dynamical frictional phenomena between fibres and curved surfaces and formation of dust have been studied. Typical are stick slip behavior and threshold stress levels for formation of dust. The emission of dust can be limited by electrostatic charging. The measured coefficients of friction of the fibres depend on the mechanical properties, micro structure, morphology and sizing of the fibres, the friction materials, the deformation rates and applied loads.
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| 3. |
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| 4. |
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| 5. |
- Christensson, Bengt, et al.
(författare)
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Analysis of Particle Emission During Simulated Processing of Multifilament Fibres
- 1994
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Ingår i: Composites Testing and Standardisation: ECCM-CTS 2. - 1855731878 ; , s. 633-640
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Konferensbidrag (refereegranskat)abstract
- The use of multifilament fibres in composites is increasing. For usability, health effects and comfort it is important to include human aspects already in the development of materials and handling techniques. This paper presents a pilot experiment for designing further experiments on emission of particles and fibres from multifilament fibres during friction, bending and tensile forces.
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| 6. |
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| 7. |
- Christensson, Bengt, et al.
(författare)
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Friction and Damage Accumulation, Formation, Morphology and Transport of Dust from Fibre Handling
- 1993
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Ingår i: Developments in the Science and Technology of Composite Materials. ; , s. 89-94
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Konferensbidrag (refereegranskat)abstract
- The mechanical stress build up in fibre handling, the dynamical frictional phenomena between fibres and curves surfaces and formation of dust have been studied. Typical are stick slip behaviour and threshold stress levels for formation of dust. The emissions of dust can be limited by electrostatic charging. The measured coefficients of friction of the fibres depend on the mechanical properties, micro structure, morphology and sizing of the fibres, the friction materials, the deformation rates and applied loads.
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| 8. |
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| 9. |
- Lastow, Orest, et al.
(författare)
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FiFi: Simulation of Dendrite Formation of Aerosol Particles on a Single Fibre
- 1992
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Ingår i: Journal of Aerosol Science. - 0021-8502. ; 23:S1, s. 105-108
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Tidskriftsartikel (refereegranskat)abstract
- A personal computer program, FiFi, that makes a real-time, two-dimensional simulation of the dynamic deposition process of particles on a single fibre, has been developed. The formation of dendrites and the particle transport as a function of different parameters are simulated. The trajectory of a spherical particle as a function of external forces and diffusion is calculated by integration and the particle moves across the display until it is captured or passes the fibre. The particles are captured directly on the fibre or on previously captured particles and form dendrites. A particle is characterised by five basic parameters which can be changed in various ways. The size and charge of the fibre are also parameters. At this state the flow around the fibre is described by either of three different air flow models, and four different electric fields can be simulated. The efficiency of any fibre-dendrite geometry can be calculated.
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| 10. |
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| 11. |
- Lastow, Orest, et al.
(författare)
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Low-voltage electrohydrodynamic (EHD) spray drying of respirable particles
- 2007
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Ingår i: Pharmaceutical Development and Technology. - : Informa UK Limited. - 1083-7450 .- 1097-9867. ; 12:2, s. 175-181
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Tidskriftsartikel (refereegranskat)abstract
- Spray drying is a widely used process to produce pharmaceutical powders. In traditional spray drying, the particle size distribution is wide and not well controlled. Using EHD atomization for spray drying offers a possibility to tailor the particle size and morphology. In conventional EHD spray drying, the generated particles are charged and need to be discharged to avoid Rayleigh breakup. Discharging adds complexity to the process and eliminates the possibility to collect the powder using an electric field. The present work describes a novel EHD spray drying setup based on a low-voltage nozzle. The low-voltage nozzle imparts moderate charge to the droplets, which makes discharging unnecessary. The charged particles can be controlled and collected by using an auxiliary electric field. The EHD spray dryer has been characterized in terms of particle size, particle morphology, process output, and yield. The size distribution of the generated particles is very narrow. Both porous and completely spherical particles can be produced. The yield of small-scale bench-top equipment was 20%, which is similar to the yield of a small-scale conventional spray dryer. The effective output with five nozzles was 75 mg/hr of dry powder. Because of the repelling forces associated with the unipolarly charged droplets, the number of nozzles can be increased without risking coalescence.
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| 12. |
- Lastow, Orest
(författare)
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Single Fibre Collection Efficiency : Infångningseffektiviteten för ett fiber
- 1994
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A personal computer program, FiFi, that makes a real-time two-dimensional simulation of the dynamic deposition process of particles on one or two fibres, has been developed. The code has been used to numerically calculate the collection efficiencies of spherical particles on a clean single fibre. The calculations are based on a 10 term expansion of a solution of Oseen's approximation of Navier-Stokes equations. An extended operational efficiency definition has been developed. The results are compared with calculations based on flow filters. The implications on the calculated results of commonly used approximations, such as zero gravity and particle size expressed as aerodynamic equivalent diameter, were quantified for spherical particles. The influences on the collection efficiency of 1-100% variations of particle density, air temperature, air viscosity, air density, air mean free path, relative humidity and air velocity were calculated. A formula to calculate the collection efficiency as a function of the particle diameter and the fibr diameter has been derived from the numerical results. The validity range of the new formula was tested. A pilot experiment with the objective to verify the theoretical results has been made. The experimental results show good agreement with the theoretical results.
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| 13. |
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