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| 2. |
- Malmberg, Filip, et al.
(författare)
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Measurement of fibre-fibre contact in three-dimensional images of fibrous materials obtained from X-ray synchrotron microtomography
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 637:1, s. 143-148
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Tidskriftsartikel (refereegranskat)abstract
- A series of wood-fibre mats was investigated using high-resolution phase-contrast microtomography at the beamline ID 19 of the European Synchrotron Radiation Facility in Grenoble, France. A method for data reduction to quantify the degree of fibre-fibre contact has been derived. The degree of fibre-fibre contact and bonding plays a fundamental role in the mechanical properties of cellulose-fibre mats, paper materials and cellulose-fibre composites. The proposed computerised automated method consists of two parts. First, fibre lumens are segmented using a watershed based method. This information is then used to identify fibre-fibre contacts in projections along the z-axis of the material. The method is tested on microtomographic images of mats made of wood pulp fibres, and is shown to successfully detect differences in the amount of fibre-fibre contact between samples. The degree of fibre-fibre contact correlates well with measured out-of-plane strength of the fibrous material.
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| 3. |
- Pereira, Joao, et al.
(författare)
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Electrooptic control of the modal distribution in a silicate fiber
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group (formerly OSA). - 1094-4087. ; 30:8, s. 12474-12483
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the use of the electrooptic effect to control the propagation constant of the guided modes in silicate few mode fibers with internal electrodes. The electrooptic effect induces a perturbation of the fiber's refractive index profile that controls intermodal interference. To increase the electrooptic effect the silicate fibers are poled. The response time is in the nanosecond range.
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| 4. |
- Silander, Isak, 1980-, et al.
(författare)
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In situ determination of the penetration depth of mirrors in Fabry-Perot refractometers and its influence on assessment of refractivity and pressure
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group (formerly OSA). - 1094-4087. ; 30:14, s. 25891-25906
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Tidskriftsartikel (refereegranskat)abstract
- A procedure is presented for in situ determination of the frequency penetration depth of coated mirrors in Fabry-Perot (FP) based refractometers and its influence on the assessment of refractivity and pressure. It is based on assessments of the absolute frequency of the laser and the free spectral range of the cavity. The procedure is demonstrated on an Invar-based FP cavity system with high-reflection mirrors working at 1.55 µm. The influence was assessed with such a low uncertainty that it does not significantly contribute to the uncertainties (k = 2) in the assessment of refractivity (<8 × 10−13) or pressure of nitrogen (<0.3 mPa).
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| 5. |
- Chakraborty, Smita, et al.
(författare)
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Impact of string interactions on the space–time evolution of hadronic vertices
- 2023
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Ingår i: European Physical Journal C. - 1434-6044 .- 1434-6052. ; 83:6
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the space–time picture of string evolution and hadron production in a fully string-based model for high energy collisions involving heavy-ions. We find that although the density of strings is quite large at the time of hadronization in a central heavy-ion collision, the initial overlap between them right after the collisions is not necessarily large. We also find that when including string-string interactions using the so-called shoving model, the density of strings is decreased which should dampen the rapid increase in string tension in the rope hadronization with multiplicity that we found in a previous paper.
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| 6. |
- Kumar, Tharagan, et al.
(författare)
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Lab-in-a-fiber-based integrated particle separation and counting
- 2023
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 23, s. 2286-
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Tidskriftsartikel (refereegranskat)abstract
- An all-fiber integrated device capable of separating and counting particles is presented. A sequence of silica fiber capillaries with various diameters and longitudinal cavities are used to fabricate the component for size-based elasto-inertial passive separation of particles followed by detection in an uninterrupted continuous flow. Experimentally, fluorescent particles of 1 μm and 10 μm sizes are mixed in a visco-elastic fluid and fed into the all-fiber separation component. The particles are sheathed by an elasticity enhancer (PEO - polyethylene oxide) to the side walls. Larger 10 μm particles migrate to the center of the silica capillary due to the combined inertial lift force and elastic force, while the smaller 1 μm particles are unaffected, and exit from a side capillary. A separation efficiency of 100% for the 10 μm and 97% for the 1 μm particles is achieved at a total flow rate of 50 μL min−1. To the best of our knowledge, this is the first time effective inertial-based separation has been demonstrated in circular cross-section microchannels. In the following step, the separated 10 μm particles are routed through another all-fiber component for counting and a counting throughput of ∼1400 particles per min is demonstrated. We anticipate the ability to combine high throughput separation and precise 3D control of particle position for ease of counting will aid in the development of advanced microflow cytometers capable of particle separation and quantification for various biomedical applications.
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| 7. |
- Vasilatou, K., et al.
(författare)
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Extending traceability in airborne particle size distribution measurements beyond 10 µm : Counting efficiency and unit-to-unit variability of four aerodynamic particle size spectrometers
- 2023
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Ingår i: Aerosol Science and Technology. - : Taylor and Francis Ltd.. - 0278-6826 .- 1521-7388. ; 57:1, s. 24-34
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to establish traceable number concentration measurements of airborne particles beyond 10 μm in particle size. To this end, the primary standards for particle number concentration at the National Metrology Institutes of Switzerland and Japan were further developed to extend their measurement capabilities. Details on the upgraded setup are provided. An inter-comparison of the two primary standards using an optical particle counter as transfer standard showed that these agree well within the stated uncertainties at polystyrene (PS) equivalent optical diameter of 15 µm. Subsequently, four Model 3321 (TSI Inc., USA) aerodynamic particle size spectrometers (APS) were calibrated against the primary standard of Switzerland using size-certified PS spheres with optical/aerodynamic diameter up to 20 µm as test aerosols. The counting efficiency profile and unit-to-unit variability of the APS units were determined. The results presented here can be useful for the analysis and interpretation of data collected by the different atmospheric aerosol networks worldwide. The outlined methodology can also be applied in the calibration of automated bio-aerosol monitors. © 2022 The Author(s).
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| 8. |
- Zhang, Miao, et al.
(författare)
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Digital rear view mirrors with Augmented Reality in comparison with traditional rear-view mirrors
- 2024
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Ingår i: IS and T International Symposium on Electronic Imaging Science and Technology. - : The Society for Imaging Science and Technology. ; 36:11
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Konferensbidrag (refereegranskat)abstract
- Recently, the traditional rear and side view mirrors have been started to be exchanged with a digital version. The aim of this study was to investigate the difference in driving performance between traditional rear-view mirrors and digital rear view mirrors which is called Camera Monitor System (CMS) in the vehicle industry. Here, two different types were investigated: CMS without or with Augmented Reality (AR) Information. The user test was conducted in a virtual environment, with four driving scenarios defined for testing. The user test results revealed that the participants' driving performance using CMS (only cameras and 2D displays without augmented information) did not improve over traditional mirrors.
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| 9. |
- Zäll, Erik, et al.
(författare)
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Environmentally sustainable electroplating of selective cobalt-chromium coating on stainless steel for efficient solar collectors
- 2022
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 245
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Tidskriftsartikel (refereegranskat)abstract
- Half of today's global energy consumption is in the form of heating and cooling. Solar collectors are the most promising sustainable alternative to fossil fuels in this sector. The most important component in a solar collector is the receiver, which by use of a selective surface absorbs and converts solar irradiance to thermal energy. Herein, a novel selective surface for low-to mid-temperature solar collectors is developed, studied and presented. The surface is produced by electroplating a cobalt-chromium coating on a stainless steel substrate using an electrolyte based on a deep eutectic solvent. Our method makes use of trivalent instead of traditionally used hexavalent chromium, which significantly reduces health-related issues and makes it more environmentally benign. We obtain a coating of chromium doped cobalt where the surface exhibits an absorptance and emittance of 0.96 and 0.14, respectively, giving it a solar-to-thermal efficiency of 0.95. An observed loss in optical efficiency, is shown to correlate to an oxidation of the metallic cobalt to Co3O4 at elevated temperatures. We further show that this oxidation can be mitigated by dip-coating a protective silica top coating, which concurrently improves the optical selectivity of the surface. The present selective surface is efficient, cheap, scalable, and easy to produce sustainably, making it competitive to industry standards. We foresee that our method will have impact on the advancement of improved low-to mid-temperature solar collectors, assisting a faster transition towards a sustainable society.
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