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  • 101.
    Renbi, Abdelghani
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Impact of PCB manufacturing process variations on trace impedance2011Ingår i: IMAPS 2011: 44th International Symposium on Microelectronics, proceedings, October 9-13, 2011, Long Beach, California, USA, Long Beach Convention Center, Washington, D.C.: International Microelectronics And Packaging Society and The Microelectronics Foundation , 2011, s. 891-895Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper demonstrates statistically the impact of PCB manufacturing variations on the char- acteristic impedance. Moreover, it shows that the characteristics of the PCBs vary across different suppliers. These differences cannot be tolerated in some applications where the characteristic impedance is restricted to be within a specific range. We sampled 3 × 20 PCBs, each batch of twenty is ordered from a different manufacturer. The sampling consist of measuring the phase shift between the reflected and the incident signals when injecting a 180 MHz sinewave into a PCB trace. The trace is selected to be the same for all samples. All the PCBs are ordered to be identical and designed for 50 Ω devices. Our conclusion was drawn after running the T-tests to assess statistically the significance of the difference occurring between the PCBs. Based on the computed P-values all the three batches are different from each other in the mean of the measured phase shift with 95 % confidence. The difference between the measured and the expected characteristic impedance is found as 3 %, 10 % and 20 % for these three manufacturers. We also witnessed board-to-board variations even within the same batch and from the same supplier due to the process instability by looking at the probability density of having the same phase shift that is equal to the mean. Some samples shown 2.6 % to 3.5 % difference above the mean.

  • 102.
    Sand, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Toivakka, Martti
    Åbo Akademi University.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions2015Ingår i: Proceedings of Computational Modelling 2015: Minerals Engineering International, 2015Konferensbidrag (Refereegranskat)
  • 103.
    Sand, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Toivakka, Martti
    Åbo Akademi University.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions2016Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 90, nr SI , s. 70-76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic behaviour of μm-scale ferromagnetic particles in suspension is of interest for various mineral beneficiation processes. It is, however, difficult to experimentally study such processes at the particle-level. In these instances it can be advantageous to resort to suitable particle simulation methods.Stokesian dynamics is a mesh-free numerical technique developed for suspensions of nm to mm size particles. The method inherently considers hydrodynamic interactions, but additional interaction models can be included depending on the system under investigation. We here present a Stokesian dynamics (SD) implementation, which allows for simulation of the motion of suspended magnetic particles in presence of an external magnetic field. The magnetic interaction model includes particle-field interactions as well as pairwise interactions between magnetised particles.Simulations are compared with experiments using a laboratory-scale flow cell. The method is shown to be realistic for studying ferromagnetic suspensions in mineral processing applications, and can be useful in understanding and predicting the efficiency of mineral separation processes.

  • 104.
    Sand, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Toivakka, Martti
    Åbo Akademi University.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Simulation of Magnetic Particle Suspensions Using the Stokesian Dynamics Technique2015Ingår i: Proceedings of Conference in Minerals Engineering 2015, Luleå: Luleå tekniska universitet, 2015Konferensbidrag (Övrigt vetenskapligt)
  • 105.
    Schäfer, Robert
    et al.
    Otto-von-Guerricke University Magdeburg.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hauptmann, Peter
    Otto-von-Guerricke University Magdeburg.
    Ultrasonic concentration measurement of aqueous solutions using PLS regression2006Ingår i: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 44, nr Supplement 1, s. e947-e950Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work demonstrates the use of a multivariate statistical technique called partial least squares (PLS) to extract material related data by analyzing spectra of ultrasonic pulses. We show how PLS can be used to estimate the concentration of sodium chloride in an aqueous solution. The paper describes the use of PLS and discusses pre-processing of ultrasonic data, the PLS algorithm as well as model validation. The measured concentrations are compared to reference values. The influence of disturbances and parameter changes is highlighted. The proposed method is easily adaptable to similar applications and permits a cost-saving implementation using existing and approved hardware

  • 106.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Direct measurement of internal material flow in a bench scale wet Low-Intensity Magnetic Separator2016Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 91, s. 55-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work an ultrasound-based measurement method is used formonitoring suspension velocity and build-up of magnetic material inside awet Low-Intensity Magnetic Separator, a process used e.g. inbeneficiation of magnetite ores. Today the only available option is tomonitor material transport between unit operations; i.e. flow rate,solids concentration, and particle size distribution of suspension flowin pipes are measured online using standard equipment.An Acoustic Backscatter System is fitted to the tank of a separator, andused to monitor the internal flow. A method called Ultrasonic VelocityProfiling is used to capture internal velocity profiles. Simultaneously,the backscatter signal intensity is used to get indications about localsolids concentration of the flow, and build-up of magnetic material. Themethods are evaluated in realistic conditions, where the effect ofvarying factors relevant to machine performance is investigated. Theincluded factors are; the slurry feed rate, the slurry solidsconcentration, the magnet assembly angle, and the drum rotational speed.The presented method gives useful information about the internal materialflow inside the separator. The velocity measurements capture the,sometimes complex, internal flow patterns, for example the presence andvelocity of a recirculating flow in the dewatering zone. Additionally,keeping a balanced material loading in the concentrate dewatering zone isimportant to separator performance. Using the signal backscatterintensity it is possible to qualitatively monitor this material loading.Generally these direct measurements can aid in improvements to machinedesign, process optimization, and process control.

  • 107.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Direct measurement of internal material flow in bench scale wet Low-Intensity Magnetic Separator2015Ingår i: Proceedings of Physical Separation '15, Minerals Engineering International , 2015Konferensbidrag (Övrigt vetenskapligt)
  • 108.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Evaluation of the applicability of ultrasonic velocity profiling in conditions related to wet low intensity magnetic separation2013Ingår i: Proceedings of Physical Separation '13, Minerals Engineering International , 2013Konferensbidrag (Övrigt vetenskapligt)
  • 109.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Evaluation of the applicability of ultrasonic velocity profiling in conditions related to wet low intensity magnetic separation2014Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 62, s. 2-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The internal material transport and selection processes of the wet low-intensity magnetic separators (LIMS) are poorly understood; this calls for improved measurement techniques. In this work an ultrasonic velocity profiling (UVP) technique for measuring how material flow velocity varies with penetration depth is presented. A measurement depth of just a couple of centimetres would greatly improve the understanding of the separation process in a LIMS.When applied to flows of mineral suspensions with high volumetric solids concentration, similar to those in the separators, UVP is unique in combining:•Non-intrusive measurements.•Operates using just one sensor element (transducer).•Relatively good spatial resolution.•Penetrates opaque suspensions.•Fast sampling rate.Here, flows are studied in a rectangular duct (50 × 75 mm). Using magnetite suspensions, measurement through the whole depth of 50 mm is made with good accuracy. Velocity profiles are presented for solids concentrations of 5% and 9% solids by volume (20% and 36% by weight). Even at 9 vol% solids it is possible to reach a penetration depth of more than 25 mm.

  • 110.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Robust estimation of particle velocity profiles in high concentration magnetite suspensions2013Ingår i: Proceedings of the 2013 International Congress on Ultrasonics / [ed] Gan Woon Siong; Lim Siak Piang; Khoo Boo Cheong, Singapore: Research Publishing Services, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the mining industry magnetite particles are transported in aqueous suspension through different stages of the process. In some stages it is of interest to monitor both the concentration and particle velocity profiles over a cross-section of the flow. In this paper an ultrasonic flow meter method based on cross-correlation of backscattered sound is presented. High solid particle content (e.g. 20-40 wt%) makes this challenging and therefore the emphasis lies on developing robust signal processing techniques for particle velocity estimation. The developed method is evaluated in laboratory experiments on flows in a rectangular duct. Transducers with centre frequency 1, 2, 4 and 5 MHz are evaluated in flows with a solid content of 20% by weight (4.7 vol% solids). Using the 2 MHz transducer a penetration depth of 50 mm is reached.

  • 111.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ultrasonic velocity profiling of flows related to wet low intensity magnetic separation2013Ingår i: Conference in Minerals Engineering: Luleå 5-6 February 2013 / [ed] Jan Rosenkranz; Tommy Karlkvist, Luleå, 2013, s. 157-168Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The internal workings of wet Low Intensity Magnetic Separators (LIMS) are poorly understood. In this work an Ultrasonic Velocity Profiling (UVP) technique for measuring material flow speed at varying depth. A measurement depth of just a couple of centimetres will greatly improve our understanding of the separation process.When applied to flows of high density mineral suspensions, similar to those in wet LIMS, UVP is unique in combining:• Non-intrusive measurements.• A single transceiver element is sufficient.• Relatively good spatial resolution.• Penetrates opaque suspensions.• Fast sampling rate.Here, flows are studied in a simple rectangular geometry (50x75 mm), using dilute magnetite suspensions; measurement through the whole depth of 50 mm is made with good accuracy. Velocity profiles are presented for different sensors at solids concentrations of 5 vol% solids.

  • 112.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Towards the measurement of local particle mass fractions in magnetite suspensions2014Ingår i: 2014 IEEE International Ultrasonics Symposium, IUS 2014: Chicago, Ill, 3-6 September 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 939-942Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the mining industry, magnetite particles are transported in suspensions with water through different stages of the process. In some of these stages, it is of interest to monitor both the concentration and particle velocity over a cross-section of the flow. High particle concentration makes development of flow measurement techniques challenging. An additional challenge is that the flow is often accessible from one side only, which further limits the selection of applicable techniques. Previous work by the authors focused on using pulse-echo ultrasound for flow velocity profile estimation. In this paper the same setup is used to simultaneously study local variations in solids concentration. Ultrasound pulses are transmitted into the suspension, and the resulting backscatter is recorded. The statistics of the backscatter depend on solids concentration, particle size distribution, particle density, etc. We demonstrate how a short-time (windowed) Power Spectral Density (PSD) estimate can be used to obtain qualitative information about local solids concentration variations. For demonstration, a magnetite suspension carrying up to 7.5 vol% particles (29 wt%, mean particle size 34 μm) is pumped through a closed rectangular channel. When the pump is stopped, pulse-echo ultrasound (with a center frequency of 2.25 or 3.5 MHz) is used to monitor the sedimentation process. Nine snapshots of the process are included. These show a time lapse of the sedimentation, with 5 s between each image. It is clear that the short-time PSD is a good indicator of local mass fraction variations.

  • 113.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Internal flow measurements in pilot scale wet low-intensity magnetic separation2016Ingår i: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 155, s. 55-63Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the mining industry, ferromagnetic particles (e.g. magnetite) are concentrated using wet low-intensity magnetic separation (LIMS). The performance is to a large extent controlled by the internal flow conditions in the separator. In previous work, it was shown how an ultrasound pulse-echo setup can be used to simultaneously measure particle velocity profiles and local solids concentration variations in laboratory conditions. In this paper, a real-world case is demonstrated where the system is installed on one of the wet LIMS at the LKAB R&D facilities in Malmberget, Sweden. For the pilot scale experiments a setup with two ultrasound transducers, mounted at the bottom of the separator tank, is used. The design of experiments method is used to study the effects of the feed solids concentration, drum rotational speed, position of the concentrate weir, and the magnet assembly angle on the measured flow patterns. The results show that it is possible to detect changes in the flow velocity patterns and the local solids concentration, as the operational conditions of the separator are varied. Of the factors studied, the drum rotational speed has the strongest influence on the overall flow velocity in the dewatering zone. Also, the presence of a recirculating flow transporting gangue particles away from the concentrate is confirmed. The factor with the strongest influence on this recirculating flow is also the drum rotational speed, together with the magnet assembly angle. Using this method it is possible to make high quality measurements of internal flow velocity profiles. It is also possible to monitor material build-up on the separator drum, and e.g. detect overload of magnetic material. The insights gained, and the methods developed, have generated new possibilities to control, optimise, and develop the wet LIMS process.

  • 114.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Monitoring Mineral Slurry Flow using Pulse-Echo Ultrasound2016Ingår i: Flow Measurement and Instrumentation, ISSN 0955-5986, E-ISSN 1873-6998, Vol. 50, s. 135-146Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultrasound based flow measurement methods have a large potential for the mining industry and its processing plants. Ultrasound travel through dense suspensions and is not affected by the magnetic fields sometimes present in this type of equipment.A cross-correlation based method is used for localized particle velocity measurements in one and two dimensions. Simultaneously, using the same data, information about local particle concentration is extracted from the power spectral density of the backscattered signal. Experiments are carried out both in simplified geometry and in full scale equipment in an iron ore pilot benefication plant.In the simple geometry it is possible to assess the precision of the methods by comparing the measurements to theory and numerical simulations. The results from the pilot plant experiments show that these methods can be applied to real world processes

  • 115.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Mining mill condition monitoring using water jet ultrasonics2013Ingår i: 2012 IEEE International Ultrasonics Symposium (IUS), Piscataway, NJ: IEEE Communications Society, 2013, s. 1913-1916Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we investigate the feasibility of using a water jet ultrasound scanning system for condition monitoring of the shell of a rotating mining mill. The practical requirements of such a system were first analyzed, which shows that it is possible to achieve the spatial resolution of 1±1 mm, using a pulse-echo setup with a pulse repetition frequency of approximately 6 kHz. Experiments were then performed on a lab-scale prototype, where typical defects were introduced. The results show that it is possible to detect and image internal defects down to a size of around than 1 ± 0.4 mm.

  • 116.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring of cracks and wear in mining mills using water squirter ultrasonics2015Ingår i: International Journal of Condition Monitoring, ISSN 0019-6398, E-ISSN 2047-6426, Vol. 5, nr 1, s. 2-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mining mills are continuously exposed to loads that give rise to wear of the liners, as well as fatigue and crack development in the steel shell. The feasibility of using water squirter ultrasonics for condition monitoring of the shell and the lining of mining mills during operation has been studied in this paper. This method will make it possible to monitor cracks in mining mills without stopping them, which can result in significant monetary savings due to less downtime and increased product quality. The practical requirements of such a system were first analysed, which shows that it is possible to achieve the spatial resolution of 1 × 1 mm, using a pulse-echo set-up with a pulse repetition frequency of approximately 6 kHz. Experiments were then performed on a lab-scale prototype, where typical defects were introduced. The results show that it is possible to detect and image internal defects down to a size of around 1 × 0.4 mm.

  • 117.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Project: Squirter Ultrasonic Thickness Gauge for Monitoring of Mining Mill Lining During Operation (SV: Mätning av tjocklek på kvarninfodring med ultraljud under drift)2014Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 118.
    Svanström, Erika
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Linder, Tomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Combined physical and statistical modeling of laser induced ultrasound signals from thin light absorbing films2013Ingår i: 2013 IEEE International Ultrasonics Symposium: [IUS 2013, Prague, Czech Republic; 21 - 25 July 2013, Piscataway, NJ: IEEE Communications Society, 2013, s. 2167-2170Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for predicting the ultrasound pulses generated by thin semi-transparent polymer films, excited by a short laser pulse. The acoustic pressure is first modeled based on the physical properties of the polymer. Partial Least-Squares Regression is then used to link the model pressure to the ultrasound pulses measured by an ultrasound transducer. The uncertainty of the regression is also simulated, showing that the method is robust to noise in the measurements

  • 119.
    Tomren, Andreas Linge
    et al.
    Department of Chemistry, University of Bergen.
    Barth, Tanja
    Department of Chemistry, University of Bergen.
    Folgerø, Kjetil
    Christian Michelsen Research AS, Bergen.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Chemometric analysis of crude oil commposition and fluid properties2011Konferensbidrag (Refereegranskat)
  • 120.
    Vlad, M. D.
    et al.
    Faculty of Medical Bioengineering, Gr. T. Popa University of Medicine and Pharmacy, Str. Kogalniceanu 9-13, 700454 Iasi.
    González, L.
    Division of Bioengineering & Biomaterials, Interdepartment Research Group for the Applied Scientific Collaboration (IRGASC), Technical University of Catalonia (UPC), Avda. Diagonal 647, 08028 Barcelona.
    Gómez, S.
    Division of Bioengineering & Biomaterials, Interdepartment Research Group for the Applied Scientific Collaboration (IRGASC), Technical University of Catalonia (UPC), Avda. Diagonal 647, 08028 Barcelona.
    López, J.
    Division of Bioengineering & Biomaterials, Interdepartment Research Group for the Applied Scientific Collaboration (IRGASC), Technical University of Catalonia (UPC), Avda. Diagonal 647, 08028 Barcelona.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Fernández, E.
    Department of Materials Science and Metallurgical Engineering, Technical University of Catalonia (UPC), Avda. Diagonal 647, 08028 Barcelona.
    Ultrasound monitoring of the setting of calcium-based bone cements2012Ingår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 23, nr 7, s. 1563-1568Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the setting of calcium-sulphate (CS) and -phosphate (CP) based bone cements (BCs) was monitored by ultrasound. The objective was to link acoustic and material properties of ceramic-based BCs from the early stages of the cement curing process. The powder phase of the CS-cement consisted of CS hemihydrate; the CP-cement was a mixture of alpha-tricalcium phosphate, CS dihydrate and hydroxyapatite. For the CS-cement, the acoustic impedance z c(t), the speed of sound c c(t) and the density ρc(t) were measured at the interval of liquid-to-powder ratios LPRs from 0.20 to 3.00 ml/g. For the CP-cement, the acoustic characteristics obtained were the z c(t) and the reflection coefficient R p,c(t), and the LPRs ranged from 0.30 to 0.40 ml/g. The resulting acoustic properties indicated that CP- and CS-cements exhibited distinctly different curing behaviour; while CS-cement expanded, CP-cement shrank with time.

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