| 691. |
- Lundberg, Joacim, 1991-, et al.
(författare)
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Temporal Variation of Road Dust Load and Its Size Distribution—a Comparative Study of a Porous and a Dense Pavement
- 2020
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media Deutschland GmbH. - 0049-6979 .- 1573-2932. ; 231:12
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Tidskriftsartikel (refereegranskat)abstract
- Resuspension of road dust contributes to air quality issues with resulting health impacts. Limited studies imply that porous pavements can initially mitigate PM10 emissions by acting as a dust trap, but the abrasion wear generates road dust and thus accelerates the clogging processes. In addition, knowledge regarding the impact of pavement types on road dust load dynamics is limited. Road traffic noise can be mitigated using porous pavements, but the use of studded tyres increases the abrasion wear of the pavement as well as increasing the noise emission. Due to this durability problem, porous pavements are rarely used in the Nordic countries where, instead, dense pavements which are abrasion resistant are more common. Linköping municipality, in Sweden, constructed a porous pavement to mitigate road traffic noise. This led to the opportunity to investigate the temporal variation of the dust load dynamics and inherent size distributions over the winter and spring in comparison to those of an adjacent dense pavement. Results, when using the wet dust sampler (WDS) method, showed similar dust load dynamics for the dense and porous pavements. The results were also compared to previous studies using the same method on different dense pavements in Stockholm, Sweden. All locations showed a seasonal variation with higher dust loads during winter and early spring and declining loads towards summer. The size distributions were more complex for the wheel tracks at the porous pavement, having primarily properties of a mixture model compared to the simple size distributions for the dense pavement. On the other hand, the dust load and size distribution were more similar between the porous and dense pavements regarding loads and shapes, indicating a less pronounced but similar behaviour between the surfaces outside of the wheel tracks.
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| 692. |
- Lundberg, Joacim, et al.
(författare)
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Texture influence on road dust load
- 2017
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Ingår i: Proceedings of the 22nd International Transportation and Air Pollution Conferens.
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Konferensbidrag (refereegranskat)
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| 693. |
- Lundberg, Joacim, et al.
(författare)
-
Texture influence on road dust load
- 2017
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Ingår i: Proceedings of the 22nd International Transportation and Air Pollution Conferens. - 9783905594676 ; , s. 14-
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Konferensbidrag (refereegranskat)abstract
- The objective of this study was to investigate the connection between pavement texture and the maximum dust load retention at a low speed. One of the main sources of PM (Particulate Matter) in the urban environment is the traffic. Traffic contributes not only to exhaust emissions, but also to direct emission from abrasion wear of pavements, tyres and brakes as well as emission from suspension of available road dust on the road surface. This dust is partially stored in the road surface macro texture. Dust accumulate on the surface due to several different mechanisms and transport phenomena’s. Examples of transport mechanisms affecting the road dust load and thus the storage in the texture include precipitation, evaporation, turbulence from traffic, wetting of the road surface binding particles to it, sanding and crushing of the sand etc.
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| 694. |
- Lundberg, Joacim, 1991-, et al.
(författare)
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Wet Dust Sampler : a Sampling Method for Road Dust Quantification and Analyses
- 2019
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Ingår i: Water, Air and Soil Pollution. - : Springer. - 0049-6979 .- 1573-2932. ; 230:8
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Tidskriftsartikel (refereegranskat)abstract
- In northern countries, the climate, and consequently the use of studded tyres and winter traction sanding, causes accumulation of road dust over winter and spring, resulting in high PM10 concentrations during springtime dusting events. To quantify the dust at the road surface, a method—the wet dust sampler (WDS)—was developed allowing repeatable sampling also under wet and snowy conditions. The principle of operation is flushing high-pressurised water over a defined surface area and transferring the dust laden water into a container for further analyses.In this paper, the latest version of the WSD is presented together with an evaluation of its performance. To evaluate the WDS, the ejected water amount was measured, as well as water losses in different parts of the sampling system, together with indicative dust measurement using turbidity as a proxy for dust concentration. The results show that the WDS, when accounting for all losses, have a predictable and repeatable water performance, with no impact on performance based on the variety of asphalt surface types included in this study, given undamaged surfaces. The largest loss was found to be water retained on the surface, and the dust measurements imply that this might not have as large impact on the sampled dust as could be expected. A theoretical particle mass balance shows small particle losses, while field measurements show higher losses. Several tests are suggested to validate and improve on the mass balances. Finally, the WDS is found to perform well and is able to contribute to further knowledge regarding road dust implications for air pollution.
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| 695. |
- Lundberg, Martin, et al.
(författare)
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Multiplexed Homogeneous Proximity Ligation Assays for High-throughput Protein Biomarker Research in Serological Material
- 2011
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 10:4, s. M110.004978-
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Tidskriftsartikel (refereegranskat)abstract
- A high throughput protein biomarker discovery tool has been developed based on multiplexed proximity ligation assays in a homogeneous format in the sense of no washing steps. The platform consists of four 24-plex panels profiling 74 putative biomarkers with sub-pM sensitivity each consuming only 1 mu l of human plasma sample. The system uses either matched monoclonal antibody pairs or the more readily available single batches of affinity purified polyclonal antibodies to generate the target specific reagents by covalently linking with unique nucleic acid sequences. These paired sequences are united by DNA ligation upon simultaneous target binding forming a PCR amplicon. Multiplex proximity ligation assays thereby converts multiple target analytes into real-time PCR amplicons that are individually quantified using microfluidic high capacity qPCR in nano liter volumes. The assay shows excellent specificity, even in multiplex, by its dual recognition feature, its proximity requirement, and most importantly by using unique sequence specific reporter fragments on both antibody-based probes. To illustrate the potential of this protein detection technology, a pilot biomarker research project was performed using biobanked plasma samples for the detection of colorectal cancer using a multivariate signature.
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| 696. |
- Lundbäck, Jonas, et al.
(författare)
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A Generic Electromagnetic Model for DOA Estimation using Arbitrary Multiport Antennas
- 2006
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Ingår i: IEEE International Symposium on Antennas and Propagation. ; , s. 2549-2552
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Konferensbidrag (refereegranskat)abstract
- A mathematical framework is introduced for optimization of antenna near-field imaging problems, based on the multipole expansion of the electromagnetic field, the Fisher information to quantify the quality of data and use of modern interior point convex optimization techniques. We consider the general problem of optimizing the measurement sensor allocation for parameter estimation in distributed systems, and in particular the problem of optimizing the measurement set-up for antenna near-field estimation. As an application example for antenna near-field imaging, we consider a relevant measurement set-up using cylindrical probing coordinates. The convex optimization problem is examined using duality theory, and it is shown that several structural properties of the optimal measurement problem can be exploited in developing an efficient interior point optimization method. In particular, we show that the cylindrical measurement set-up yields a Fisher information matrix with block diagonal structure, a feature which can be directly exploited in the optimization algorithm by reducing the number of dual decision variables.
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| 697. |
- Lundbäck, Jonas, et al.
(författare)
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A Generic Electromagnetic Model for DOA Estimation Using Arbitrary Multiport Antennas
- 2006
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Ingår i: IEEE Antennas and Propagation Society International Symposium 2006. - 1424401232 ; , s. 2549-2552
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Konferensbidrag (refereegranskat)abstract
- In this paper, a generic electromagnetic model is utilized for arbitrary multiport antennas e.g., vector sensors applied in DOA estimation, which was exploited for the statistical analysis of DOA and polarization estimation. By utilizing the spherical vector wave expansion of the electromagnetic field to completely characterize the multiport antennas a general framework for modelling an antenna configuration based on measurements or computations including e.g., mutual coupling is obtained. The array manifold can easily be expanded over a dense spatial grid to enable high-resolution DOA estimation without demanding further measurements of the antenna characteristics.
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| 698. |
- Lundgren, Johan, et al.
(författare)
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A Near-Field Measurement and Calibration Technique : Radio-Frequency Electromagnetic Field Exposure Assessment of Millimeter-Wave 5G Devices
- 2021
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Ingår i: IEEE Antennas & Propagation Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 1045-9243 .- 1558-4143. ; 63:3, s. 77-88
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Tidskriftsartikel (refereegranskat)abstract
- Accurate and efficient measurement techniques are needed for an exposure assessment of 5G portable devices, which are expected to utilize frequencies beyond 6 GHz with respect to radio-frequency (RF) electromagnetic field (EMF) exposure limits. At above 6 GHz, these limits are expressed in terms of the incident power density, thus requiring the EMFs to be evaluated with high precision in close vicinity to the device under test (DUT), i.e., in the near-field region of the radiating antenna. This article presents a cutting-edge near-field measurement technique suited for these needs. The technique, based on source reconstruction on a predefined surface representing the radiating aperture of the antenna, requires two sets of measurements: one of the DUT and one of a small aperture. This second measurement functions as a calibration of both the measurement probe impact on the received signal and the experimental setup in terms of the relative distance between the probe and the DUT. Results are presented for a 28- and a 60-GHz antenna array, both of which were developed for 5G applications. The computed power density is compared with simulations at evaluation planes residing as close as one fifth of a wavelength (lambda/5) away from the DUT.
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| 699. |
- Lundgren, Johan, et al.
(författare)
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IR and Metasurface based mm-Wave Camera
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a technique to measure low-power electromagnetic fields from mm-wave devices non-intrusively by combining a metasurface, designed to absorb power and focus the radiated power in a thermally isolated region, with an infrared camera. The metasurface consists of thermally isolated elements of low mass and highly emissive material for maximal IR conversion of the incident wave. The IR camera captures the converted energy and indirectly images the incident electromagnetic field on the metasurface. The setup combines multi-scale, multi-physical processes to conduct measurements of the incident electromagnetic fields in real time. In this work, the technique is presented and discussed. Measurements are carried out to demonstrate the technique and image the electromagnetic field of a radiating device. The results compare well with simulations and the technique can measure the low power density levels of consumer devices, as well as provide a general visualization of electromagnetic fields in a live setting.
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| 700. |
- Lundgren, Johan, et al.
(författare)
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Iterative Calculation of Characteristic Modes Using Arbitrary Full-Wave Solvers
- 2023
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225. ; 22:4, s. 799-803
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Tidskriftsartikel (refereegranskat)abstract
- An iterative algorithm is adopted to construct approximate representations of matrices describing the scattering properties of arbitrary objects. The method is based on the implicit evaluation of scattering responses from iteratively generated excitations. The method does not require explicit knowledge of any system matrices (e.g., stiffness or impedance matrices) and is well-suited for use with matrix-free and iterative full-wave solvers, such as FDTD (Finite-difference time-domain method), FEM (Finite element method), and MLFMA (Multilevel Fast Multipole Algorithm). The proposed method allows for significant speed-up compared to the direct construction of a full transition matrix or scattering dyadic. The method is applied to the characteristic mode decomposition of arbitrarily shaped obstacles of arbitrary material distribution. Examples demonstrating the speed-up and complexity of the algorithm are studied with several commercial software packages.
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