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  • 1. Andersson, Tobias
    et al.
    Thurley, Matthew
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Carlson, Johan E.
    A machine vision system for estimation of size distributions by weight of limestone particles during ship loading2012Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 25, nr 1, s. 38-46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The size distribution as a function of weight of particles is an important measure of product quality in the mining and aggregates industries. When using manual sampling and sieving, the weight of particles is readily available. However, when using a machine vision system, the particle size distributions are determined as a function of the number of particles. In this paper we first show that there can be a significant weight-transformation error when transforming from one type of size distribution to another. We also show how the problem can be overcome by training a classifier and scaling the results according to calibrated average weights of rocks. The performance of the algorithm is demonstrated with results of measurements of limestone particles on conveyor belts.

  • 2. Barracó, Marc
    et al.
    Fernández, Enrique
    Torres, Ricardo
    López, José
    Bosch, Ricard
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ultrasound monitoring of the setting of injectable bone cement biomaterials for spinal surgery applications2005Ingår i: Proceedings 2nd Annual European Rheology Conference, 2005, s. 133-133Konferensbidrag (Refereegranskat)
  • 3.
    Berg, Sven
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jonsén, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    High pressure characterization and modelling of CaCO3 powder mix in the Bridgman anvil apparatus2012Ingår i: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 32, nr 4, s. 490-508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For investigating high pressure sintering processes, numerical models can be used. This will demand material models which give realistic mechanical response throughout the whole parameter space of the actual process. As the pressures become higher, the material density approaches its full theoretical value and the elastic part of the material properties becomes increasingly important. In this investigation, Poisson's ratio was determined using ultrasonic pulse-echo measurements. A new elastic model and an improved plasticity model were implemented into a user-defined material subroutine in a finite element (FE) code. To experimentally investigate the load displacement response and pressure distribution in powder compacts during pressing, a pressure instrumented Bridgman anvil apparatus was used. Validation of the FE model was conducted against experimental data from pressing experiments using two different start densities. The results show that the simulation model is indeed capable of reproducing load–thickness curves and pressure profiles reasonable close to the experimental curves.

  • 4.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Joint measurement of particle distribution and particle mass fractions in multiphase flows using a clamp-cn PVDF array2001Ingår i: Proceedings of the Flow Measurement 2001 International Conference, National Engineering Laboratory , 2001Konferensbidrag (Refereegranskat)
  • 5.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mass fraction measurements in multiphase flows using a clamp-on PVDF array2000Ingår i: Proceedings: 2000 IEEE Ultrasonics Symposium : October 22 - 25, 2000, Hotel Caribe Hilton, San Juan, Puerto Rico ; an international symposium / [ed] Susan C. Schneider, Piscataway, NJ: IEEE Communications Society, 2000, s. 471-474Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present a method for the measurement of mass fractions of iron ore in two-phase flows consisting of water and iron ore particles. The proposed method uses a clamp-on PVDF transmitter and a 12-element PVDF receiver array to measure the excess attenuation of pulsed ultrasound due to the presence of particles. From the measured data we are able to extract a quantity that varies linearly with particle mass fraction in the range from 0 to 13%. With the proposed method we can measure the mass fraction in whole percent, at a 95% confidence level. Using an array of receivers we are also able to calculate an attenuation profile over a cross section of the flow, which indicates how the particles are distributed within the flow. This is used to examine how the particle distribution is affected by flow speed, flow meter position, and mass fraction, respectively.

  • 6.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Multiphase flow measurements using ultrasound1999Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In process industries such as for example the oil and gas industry, the paper pulp industry, and the mining industry, multiphase flows are common. It is often of interest to measure the mass fractions of the different phases. In for example the mining industry, iron ore powder is transported using water, and there is a need of measurement techniques to monitor the particle mass fraction. Most existing techniques are either invasive, inaccurate, or too slow to be used in an on-line manner. The long-term goal of this research project is to develop a method for measuring mass fractions and mass fraction velocities, using ultrasound. The first two papers in this thesis consider how scattering of sound can be measured, and how this can be used to measure mass fractions. The ideas are verified with experiments. The third paper is on optimal experimental design. The problem is selecting suitable experiments from a large candidate set. We present a new algorithm for generating optimal designs. The methods in the first two papers can be extended to incorporate more of the underlying physics, as well as using more sophisticated multi-dimensional signal processing techniques.

  • 7.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ultrasonic characterization of materials and multiphase flows2002Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with three different applications of ultrasound measurement technology. In process industries like the mining industry, the oil and gas industry, and the paper pulp industry, multiphase flows play an important role. It is of interest to measure several different parameters of these flows, such as the mass fractions and the mass fraction velocities of the different phases. There are currently no single technique available that can measure all of these properties, and commercial multiphase flow meters are in practice a combination of several flow meters that each measure different parameters. The long-term goal of the project presented in this thesis is to develop an ultrasonic technique that can measure all of these properties. The first focus of the work presented in this thesis has been to develop an ultrasonic method that can measure the mass fraction of particles in a solid/liquid multiphase flow. The technique is based on a sensor array that measures an entire cross section of the flow. The use of an array makes it possible to measure the particle distribution. This can then be used to detect static installation effects, thus enabling the use of single point sensor. The sensor array used is clamped on to the outside of the flow pipe which means the technique is completely non-invasive. The second focus is on imaging of opaque flows. While traditional optical techniques such as LDV, etc. does not work for opaque media, there is no such restriction on the ultrasonic method. The imaging technique, called ultrasonic speckle correlation velocimetry (USV) has been applied to image vortices in flows, and to measure particle velocity profiles in multiphase flows. The third and last contribution is in the field of non-destructive evaluation (NDE) of materials. In a biomaterial engineering project, the goal has been to develop an injectable bone cement that can be used to repair or replace fractured bone. During the setting reaction, the cement undergoes a series of phase changes, which have implications on how the cement can be used. The research is motivated by the lack of satisfying standards to measure the setting time. The existing methods are based on mechanical testing and visual examination, which makes them time-consuming and subjective. The ultrasonic technique presented in this thesis provides a non-destructive and objective way to determine both the setting time and some mechanical properties of the cement, during the entire setting process. The thesis consists of an introductory part and a collection of seven papers.

  • 8.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Utveckling av analysmetoder för bio- och naturgas med hjälp av ultraljud2005Ingår i: Nytt om biogas, ISSN 1651-5439, nr 1, s. 10-11Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 9.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Pär-Erik
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Håkansson, Mikael
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Castano, Miguel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Linder, Tomas
    Projekt: SCOPE Norra2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    SCOPE Norra är ett samarbetskonsortium för forskning och utveckling tillsammans med massa- och pappersindustrin i Norrbotten och Västerbotten. Projektet koordineras av centrumbildningen ProcessIT Innovations.Inom SCOPE Norra pågår ett flertal delprojekt, uppdelat på ett antal fokusområden.Huvudfinansiär för konsortiet är Tillväxtverket genom medel från EU:s strukturfonder.

  • 10.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bouchet, G
    Institut de Mécanique des Fluides, Strasbourg.
    Maurel, A
    Laboratoire Ondes et Acoustique, Ecole Supérieure de Physique et de Chimie Industrielles, Paris.
    Simultaneous characterization of velocity and temperature profiles using time-reversal2001Ingår i: 17th International Congress on Acoustics, Rome, September 2 - 7, 2001: Session 4A.01, Rome, 2001Konferensbidrag (Refereegranskat)
  • 11.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Carlson, Rolf
    Department of Chemistry, University of Tromsoe.
    Prediction of molar fractions in two-component gas mixtures using pulse-echo ultrasound and PLS regression2006Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 53, nr 3, s. 606-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The composition, and thus the energy content and monetary value of natural gas and biogas, vary considerably depending on the source. Present energy measurement techniques are riot suitable for online use. We show with experiments on mixtures of ethane (C/sub 2/H/sub 6/) and oxygen (O/sub 2/) how partial least squares regression (PLSR) can be used to predict the molar fraction of ethane in the mixtures, given spectral data from ultrasonic pulse-echo measurements. The PLSR technique is compared with the standard principal component regression (PCR), and we show that PLSR yields better predictive performance.

  • 12.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Analys av energigaser med ultraljud2007Ingår i: THULE: Kungl. Skytteanska Samfundets årsbok 2007, Umeå: Kungl. Skytteanska samfundet , 2007, s. 103-112Kapitel i bok, del av antologi (Övrig (populärvetenskap, debatt, mm))
  • 13.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Estimation of particle size distributions in solid/liquid suspensions based on wide-band ultrasound attenuation measurements2010Ingår i: IEEE International Ultrasonics Symposium, IUS 2010: San Diego, CA; 11 October 2010 through 14 October 2010, Piscatawary, NJ: IEEE Communications Society, 2010, s. 707-710Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper demonstrates a strategy for rapid estimation of particle size distributions based on wide-band ultrasound attenuation measurement in solid/liquid suspensions. The excess attenuation due to the presence of particle is first measured as a function of frequency, in a suspension of known particle mass fraction. A model of this attenuation that incorporates the dependency of ultrasound frequency, particle mass fraction, and particle size distribution is then required. An algorithm is then presented that estimates the parameters of the underlying model, thus obtaining an estimate of the particle size distribution. The algorithm is evaluated with numerical simulations as well as measurement on suspensions of Dolomite particles. The results show that the estimated particle size distribution agrees with what is to be expected from the mechanical sieving used in preparation of the samples.

  • 14.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Measurement systems engineering: design, modeling, and computational methods2018Bok (Övrigt vetenskapligt)
  • 15.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ultrasound measurements in moving multi-phase supsensions1998Självständigt arbete på avancerad nivå (masterexamen), 40 poäng / 60 hpStudentuppsats (Examensarbete)
  • 16.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Andren, Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mohamad, Medhat
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Beek, Jaap van de
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Monitoring Changes in Mechanical Properties of Rock Bolts Using a Low-Power Coded-Excitation Scheme2018Ingår i: 2018 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), IEEE, 2018, artikel-id 8580038Konferensbidrag (Refereegranskat)
    Abstract [en]

    In-situ inspection and quality assessment of rock bolts and other load-bearing structural elements, has received significant attention over the years, but there are still no techniques available capable of monitoring changes over time in mechanical properties of already installed bolts. Since mechanical changes will also affect the propagation of mechanical waves, ultrasound is a strong candidate. In this paper we propose a technique based on Orthogonal Frequency Division Multiplexing (OFDM) for coding the transmitted ultrasound pulse in such a way that the propagation channel (transducer and rock bolt combined) can be estimated. We show that a transmit voltage of 1.1 V r.m.s. is sufficient to obtain reliable channel estimates even in bolts as long as one meter. The channel estimates are then used to predict changes in tensile stress on the bolt, from experiments conducted in a laboratory environment.

  • 17.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Gasson, J.R.
    University of Bergen.
    Barth, T.
    University of Bergen.
    Eide, I.
    Statoil Research Centre, Trondheim.
    Extracting homologous series from mass spectrometry data by projection on predefined vectors2012Ingår i: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 114, s. 36-43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multivariate statistical methods, such as Principal Component Analysis (PCA), have been used extensively over the past decades as tools for extracting significant information from complex data sets. As such they are very powerful and in combination with an understanding of underlying chemical principles, they have enabled researchers to develop useful models. A drawback with the methods is that they do not have the ability to incorporate any physical / chemical model of the system being studied during the statistical analysis. In this paper we present a method that can be used as a complement to traditional chemometric tools in finding patterns in mass spectrometry data. The method uses a pre-defined set of equally spaced sequences that are assumed to be present in the data. Allowing for some uncertainty in the peak locations due to the uncertainties for the measurement instrumentation, the measured spectra are then projected onto this set. It is shown that the resulting scores can be used to identify homologous series in measured mass spectra that differ significantly between different measured samples. As opposed to PCA, the loading vectors, in this case the pre-defined homologous series, are readily interpretable.

  • 18.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grennberg, Anders
    A new algorithm for constructing optimal experimental designs1998Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In any experimental science we are sometimes confronted with new experimental situations, where underlying physical models are unknown. After a first attempt at identifying physical variables that could effect the experimental result, we need to perform what is called a screening experiment. The objective is to conduct a small number of experiments that span as much of the experimental space as possible, to merit further experiments in smaller, more promising test systems. In this report we present an algorithm that, given a set of possible experiments, selects a subset of these. The selection is designed to cover as much variation as possible in the experimental space, and to assure a minimized expected mean squared error in the model parameter estimation. We verified the algorithm with an example taken from organic synthesis.

  • 19.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hägglund, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Characterization of thin layers in multi-layered structures: on the problem of finding starting values for numerical solutions to inverse problems2010Ingår i: 2009 IEEE Ultrasonics Symposium: Rome, Italy, 20 - 23 September 2009, Piscataway, NJ: IEEE Communications Society, 2010, s. 1537-1540Konferensbidrag (Refereegranskat)
    Abstract [en]

    Several model-based techniques have been proposed for characterizing thin layers within multi-layered materials. One problem with these methods is that the models are non-linear with respect to the parameters. Hence, iterative numerical methods must be used estimating the model parameters, i.e. for solving the inverse problem based on measurements. For material structures where the propagation times through the individual layers are shorter than the duration of the transmitted ultrasound pulse, the received waveform will consist of several overlapping echoes. For the parameter estimation to work, good initial guesses of the times of flight are required, which are difficult to obtain due to the severe overlap of the echoes. In this paper we propose a filtering scheme, that compresses the transmitted pulse into a shorter pulse, thus enabling the echoes from within the material structure to be detected. The method is evaluated using simulations on a three-layered material for varying signal-to-noise conditions.

  • 20.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hägglund, Fredrik
    Martinsson, Jesper
    Saremi, Amin
    Luleå University of Technology.
    Calibration of simulation models for ultrasonic transducers based on implicit calibration2009Ingår i: 2008 IEEE Ultrasonics Symposium: IUS ; Beijing, China, 2 - 5 November 2008, Piscataway, NJ: IEEE Communications Society, 2009, s. 1528-1531Konferensbidrag (Refereegranskat)
    Abstract [en]

    There are numerous software packages available for modeling of the sound pressure fields emitted by ultrasound transducers and transducer arrays. Accurate modeling of a real-world transducer requires knowledge of several parameters that are generally not known. This paper presents an estimation principle that can be used to calibrate such models, based on measurements of the sound field. The model separates the problem into estimation of the transducer's electro-mechanical impulse response and its spatial impulse response. The latter being what the software packages generally model. We demonstrate the principle with measurements of the sound field from a non-focused 5 MHz transducer. The results show that the modeled sound field agrees well with measurements.

  • 21.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nilsson, M.
    Polytechnical University of Catalonia, Barcelona.
    Fernández, E.
    Polytechnical University of Catalonia, Barcelona.
    Planell, J. A.
    Polytechnical University of Catalonia, Barcelona.
    Monitoring the setting of CaSO4 H2O-based cements with pulse-echo ultrasound2002Konferensbidrag (Övrigt vetenskapligt)
  • 22.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ovacikli, Aziz Kubilay
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system. Rubico Vibration Analysis AB.
    Pääjärvi, Patrik
    Rubico Vibration Analysis AB.
    Material Impulse Response Estimation from Overlapping Ultrasound Echoes Using a Compressed Sensing Technique2017Ingår i: IEEE International Ultrasonics Symposium, IUS, IEEE Computer Society, 2017, artikel-id 8091788Konferensbidrag (Refereegranskat)
    Abstract [en]

    When investigating thin materials with pulse echo ultrasound, multiple reflections (reverberations) from the layer(s) will overlap. It is therefore difficult to deduce information about speed of sound, thickness, density, etc. from the raw data. In order to extract this information, the overlapping pulses must be either decoupled or we must find some model of the material sample describing the wave propagation. It is, however, often reasonable to assume that the the number of reflections is small relative to the number of samples in the record signal of interest. In other words, the system describing the reverberations is sparse. In this paper we investigate, with simulations and with experiments on a 4.8 and 2.2 mm thick glass plate, respectively, how the framework of compressed sensing can be adopted in order to retrieve the impulse response of the material specimen

  • 23.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ovacikli, Aziz Kubilay
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system. Rubico Vibration Analysis AB.
    Pääjärvi, Patrik
    Rubico Vibration Analysis AB.
    Material Impulse Response Estimation from Overlapping Ultrasound Echoes Using a Compressed Sensing Technique2017Ingår i: IEEE International Ultrasonics Symposium, IUS, IEEE Computer Society, 2017, artikel-id 8092248Konferensbidrag (Refereegranskat)
    Abstract [en]

    In ultrasound examination of thin multi-layered materials, the received signal is, in both through-transmission and pulse-echo configurations, a superposition of multiple reflections from inside the sample. If the layer thicknesses are small compared to the duration of the emitted ultrasound pulse, the received signal will be a sum of overlapping ultrasound pulses. In such scenarios, estimation of the layer thicknesses is challenging. Previous work has adopted model-based decomposition of the overlapping echoes, or various pulse compression or deconvolution schemes, in order to better reveal the arrival times of each individual echo.

  • 24.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ranefjärd, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Trulsson, Felix
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A Subspace Based Method for Near Transducer Interference Suppression2018Ingår i: 2018 IEEE International Ultrasonics Symposium, IEEE, 2018, artikel-id 8579817Konferensbidrag (Refereegranskat)
    Abstract [en]

    In applications of direct -contact ultrasound, operating in pulse -echo mode, the transient resulting from the excitation of the transducer will mask any reflections from scatterers near the transducer surface. This results in a so called dead zone, preventing any defects to be detected. This is normally solved by introducing a delay line between the transducer and the specimen. There are drawbacks with this approach, and therefore we propose an alternative technique, which instead suppresses the transient from the excitation by a statistical modeling technique. This paper describes an algorithm for reduction of the dead zone and shows with experiments using both a single -element transducer and a 128 element linear array, that the transient from the transducer excitation can be suppressed sufficiently well to reveal side -drilled holes in a test block, which were previously masked.

  • 25.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Svanström, Erika
    Onur, Tugba Özge
    Department of Electronics Engineering, Bulent Ecevit University.
    Estimation of the Flexural Stiffness of Thin Plates Using a Single Low-Cost Passive Sensor2014Ingår i: 2014 IEEE International Ultrasonics Symposium, IUS 2014: Chicago, Ill., 3-6 September 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 142-145Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, a bending (flexural) wave mode in a thin plate is excited by tapping gently on the surface. The wave is recorded with single low-cost piezo-electric sensor. Due to the dispersive nature of this wave mode, the shape of the recorded signal depends on the flexural stiffness parameter of the plate. The recorded signal is also affected by the transfer function of the excitation and the sensor. In this paper we show, with simulations and measurements on a thin quartz glass plate, that the effect of the sensor and excitation can be decoupled from the bending wave, and that the flexural stiffness parameter can be estimated using a single sensor.

  • 26.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Taavitsainen, Veli-Matti
    Department of Mathematics, EVTEK University of Applied Sciences, Espoo.
    Estimation of reaction kinetics using ultrasound2008Ingår i: 2008 IEEE Ultrasonics Symposium: IUS ; Beijing, China, 2 - 5 November 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 192-195Konferensbidrag (Refereegranskat)
    Abstract [en]

    In many ultrasound measurement situations, deriving models for the acoustic wave propagation through the system being studied is complicated. In such cases, we are often limited to study correlations between observed acoustic properties and the underlying physical properties. Sometimes this can be automated by use of statistical or empirical models. However, this often requires extensive calibration, and it does not provide as much understanding of the underlying system as we would like. In this paper we present a general methodology for estimation of parameters of physical models based on indirect observations. The principle is demonstrated for a system where the kinetic behavior of a chemical reaction is modeled, and where measurements of ultrasound attenuation are used to estimate the model parameters. Experimental results show that we can use ultrasound to measure mass fractions of the different constituents as a function of the reaction time.

  • 27.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Taavitsainen, Veli-Matti
    EVTEK University of Applied Sciences, Espoo.
    Ultrasonic measurement of the reaction kinetics of the setting of calcium sulfate bone cements using implicit calibration2008Ingår i: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 22, nr 11-12, s. 752-757Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Injectable bone cements based on calcium sulfate and calcium phosphates are being developed for use as bone defect filling and reinforcement of osteoporotic bones. For developers and end-users, kinetic properties of the setting reaction of such cements are of great interest. Existing standards for setting time measurement are based on visual examination of the cement surface and thus suffer from poor repeatability and subjectivity. Implicit calibration provides the means of determining parameters of a physical model at the same time as a calibration based on regression. This enables the use of indirect observations for the determination of implicit model parameters. In this paper, we study the hydration of calcium sulfate hemihydrate into calcium sulfate dihydrate, by combining multivariate calibration with a physical model of the reaction kinetics. The physical model contains three parameters, the reaction rate, the reaction order and a time delay. These parameters are estimated from ultrasound amplitude spectra. The resulting model fit has an R2 value of 99.9%.

  • 28.
    Carlson, Johan E.
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Tomren, Andreas Linge
    Department of Chemistry, University of Bergen.
    Folgerø, Kjetil
    Michelsen Centre for Industrial Measurement Science & Technology, P.O.Box 6031, NO- 5892 Bergen, NORWAY, Christian Michelsen Research AS, Bergen.
    Barth, Tanja
    Department of Chemistry, University of Bergen.
    Estimation of dielectric properties of crude oils based on IR spectroscopy2014Ingår i: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 139, s. 1-5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dielectric properties of crude oils play an important role in characterization and quality control. Measuring permittivity accurately over a wide range of frequencies is, however, a time-consuming task and existing measurement methods are not easily adapted for real-time diagnostics. IR spectroscopy, on the other hand, provides rapid measurements of fundamental molecular properties.In this paper we show that by using multivariate calibration tools such as PLS regression, it is possible to extract dielectric properties of crude oils directly from IR spectra, in addition to conventional interpretation of the spectra, hence reducing the need for direct electrical measurements. Results on 16 different oil samples show that the dielectric parameters obtained with the proposed method agree well with those obtained using direct permittivity measurements. The PLS regression method has also been extended with Monte-Carlo simulation capabilities to account for uncertainties in the data

  • 29.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grennberg, Anders
    Ultrasonic measurements of particle concentration in a multiphase flow1999Ingår i: Proceedings: 1999 IEEE Ultrasonics Symposium : October 17 - 20, 1999, Caesars Tahoe, Nevada, USA ; an international symposium / [ed] S. C. Schneider, Piscataway, NJ: IEEE Communications Society, 1999, s. 757-760Konferensbidrag (Refereegranskat)
    Abstract [en]

    Non-invasive measurements of multiphase flows have several important applications in industry. In this paper we present a method that uses pulsed ultrasound and two small receivers to determine the mass concentration of iron ore particles in water. The proposed method is based on the assumption that when ultrasound is transmitted through a scattering medium, the shape of the energy lobe changes. In this paper we use two receivers to monitor how the lobe changes. We show with experiments how the proposed method can be used to determine particle mass fractions from 3 percent and up, with an accuracy of ±1 percent of the mass fraction. In the experiments we used a 3 MHz transmitter and two receivers, one along the acoustical axis and the other 6 mm off-axis, to measure the mass fraction of a polydisperse suspension of iron ore powder in water.

  • 30.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grennberg, Anders
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Multiphase flow characterized by scattering of ultrasound1998Ingår i: Proceedings - The 9th International Conference on Flow Measurement: FLOMEKO / [ed] Jerker Delsing, Kista: ITF , 1998, s. 493-497Konferensbidrag (Refereegranskat)
  • 31.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ing, R.K.
    Laboratoire Ondes et Acoustique, Paris.
    Bercoff, J
    Laboratoire Ondes et Acoustique, Paris.
    Tanter, M
    Laboratoire Ondes et Acoustique, Paris.
    Vortex imaging using two-dimensional ultrasonic speckle correlation2001Ingår i: Proceedings: 2001 IEEE Ultrasonics Symposium : October 7 - 10, 2001, Omni Hotel, Atlanta, Geo / [ed] Donald E. Yuhas, Piscataway, NJ: IEEE Communications Society, 2001, s. 559-562Konferensbidrag (Refereegranskat)
    Abstract [en]

    In previous work, it has been shown that ultrasonic speckle velocimetry can be used to measure local particle velocities in flows. So far the technique has been applied to monitor stationary processes. In this paper, we show how ultrasonic speckle velocimetry can be used to dynamically map the two-dimensional velocity profiles of vortices caused by an obstacle within a flow. Thanks to the great versatility of our multi-channel system, it is possible to capture as much as 5000 images per second, thus enabling us to monitor very fast moving processes. To date, two transducer arrays are used to estimate the 2D motion vector of local particles. We also discuss possible modifications and improvements of the system that could lead to the use of a single array of transducers to dynamically map the vectorial velocity fields of flows

  • 32.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ing, Ros Kiri
    Laboratoire Ondes et Acoustique, Paris.
    Ultrasonic particle velocimetry in multiphase flows2002Ingår i: Proceedings: 2002 IEEE Ultrasonics Symposium : October 8 - 11, 2002, Forum Hotel, Munich, Germany ; an international symposium / [ed] Donald E. Yuhas, Piscataway, NJ: IEEE Communications Society, 2002, s. 761-764Konferensbidrag (Refereegranskat)
    Abstract [en]

    Two-dimensional ultrasonic speckle correlation velocimetry (USV) is a new technique that allows to image moving scattering media, at a high frame-rate. In this paper we apply the. technique to determine two-dimensional particle velocity profiles of multiphase flows. Experiments are realized with suspensions of Sonazoid (medical contrast agent) and Magnetite (Fe/sub 3/O/sub 4/) in water. All measurements are performed in a vertical pipe with the flow moving downwards. The two-dimensional particle velocity profiles are then compared with a reference liquid volume flow velocity. As expected from theory, the heavier Magnetite particles have slightly higher velocity than the liquid whereas the contrast agent simply follows the liquid motion. The proposed technique can be used in combination with other techniques to measure the mass flow of the solid phase, in solid/liquid multiphase flow. This is generally more interesting than-measuring the bulk mass or volume flow.

  • 33.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ing, Ros Kiri
    Laboratoire Ondes et Acoustique, Paris.
    Ultrasonic speckle correlation imaging of 2D particle velocity profiles in multiphase flows2003Ingår i: Flow Measurement and Instrumentation, ISSN 0955-5986, E-ISSN 1873-6998, Vol. 14, nr 4-5, s. 193-200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two-dimensional ultrasonic speckle correlation velocimetry (USV) is a new technique that allows imaging of moving scattering media, at a high frame-rate. In this paper we apply the technique to determine two-dimensional particle velocity profiles of multiphase flows. Experiments are realized with suspensions of Sonazoid (medical contrast agent) and Magnetite (Fe3O4) in water. All measurements are performed in a vertical pipe with the flow moving downwards. The two-dimensional particle velocity profiles are then compared with a reference liquid volume flow velocity. As expected from theory, the heavier Magnetite particles have slightly higher velocity than the liquid, whereas the contrast agent simply follows the liquid motion. The proposed technique can be used in combination with other techniques to measure the mass flow of the solid phase, in solid/liquid multiphase flow. This is generally more interesting than measuring the bulk mass or volume flow.

  • 34.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lundin, Peter
    Swerea KIMAB AB.
    Measurement of the Clamping Force Applied by Load-Bearing Bolts Using a Combination of Compression and Shear Ultrasonic Waves2015Ingår i: 2015 IEEE International Ultrasonics Symposium (IUS 2015): Taipei, 21-24 Oct. 2015, Piscataway, NJ: IEEE Communications Society, 2015, artikel-id 7329418Konferensbidrag (Refereegranskat)
    Abstract [en]

    Quantitative measurement of the clamping or tightening force of rods and bolts is important when assessing the structural integrity of various constructions. This paper shows that by using a bi-wave ultrasonic pulse-echo technique, it is possible to determine this tightening force without the need of extensive calibration prior to installing the bolts. We show that the ratio of the time-of-flight (TOF) between the transversal and the longitudinal waves changes linearly with the clamping force and that we only need to know the TOF of the unstrained bolt prior to installment. This is then demonstrated experimentally on a 1.1 m rock bolt, using pulses that propagated 6.6 m. Two different methods for estimation of the TOF ratio are evaluated.

  • 35.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Jesper
    Nordenvaad, Magnus Lundberg
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Measurement of methane content in upgraded biogas using pulse-echo ultrasound2008Ingår i: Proceedings of the International Congress on Ultrasonics: Vienna, April 9-13, 2007, Paper ID 1366, Session R03: Acoustic sensors, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present an ultrasonic pulseecho technique for estimating the methane (CH4) content in binary mixtures of CH4 and carbon dioxide (CO2). The method is based on parametric estimation of phase velocity and frequency dependent attenuation in combination with Partial Least-Squares Regression (PLSR). The technique is verified using experiments on mixtures with a volume fraction of CO2 in the range of 0 % -10 %. The experiments show that the CH4 content can be accurately estimated with high repeatability.

  • 36.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A simple scattering model for measuring particle mass fractions in multiphase flows2002Ingår i: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 39, nr 8, s. 585-590Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we present a simple theoretical model of how pulsed ultrasound is attenuated by the particles in a solid/liquid flow. The theoretical model is then used to predict the attenuation of sound, given the mass fraction, the density, and the size distribution of the solid particles. The model is verified experimentally for suspensions of 0–10% (by mass) Dolomite ((Ca,Mg)CO3) particles and water. The experimental results show that the attenuation of sound due to particles varies linearly with mass fraction, and that the proposed theoretical model can be used to predict this attenuation. In all experiments the transmitter and receiver array were clamped onto the pipe wall, thus providing a completely non-invasive and non-intrusive measurement technique.

  • 37.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Exploring interaction effects in two-component gas mixtures using orthogonal signal correction of ultrasound pulses2005Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, nr 5, s. 2961-2968Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Within Sweden and the EU, an increased use of biogas gas and natural gas is encouraged to decrease emission of carbon dioxide. To support more effective manufacturing, distribution, and consumption of energy gases, new methods for the measurement of the calorimetric value or the gas composition are needed. This paper presents a method to extract and visualize variations in ultrasound pulse shape, caused by interaction effects between the constituents of a two-component gas mixture. The method is based on a combination of principal component analysis and orthogonal signal correction. Pulse-echo ultrasound experiments on mixtures of oxygen and ethane in the concentration range from 20% to 80% ethane show that the extracted information could be correlated with the molar fraction of ethane in the mixture

  • 38.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ultrasonic measurement of molar fractions in gas mixtures by orthogonal signal correction2004Ingår i: 2004 IEEE Ultrasonics Symposium: 23 - 27 August 2004, Palais des Congrès, Montréal, Canada ; a conference of the IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society (UFFC-S) ; [part of IEEE International Ultrasonics, Ferroelectrics, and Frequency Control 50th Anniversary Joint Conference] / [ed] Marjorie Passini Yuhas, Piscataway, NJ: IEEE Communications Society, 2004, s. 821-825Konferensbidrag (Refereegranskat)
    Abstract [en]

    Within Sweden and the EU, an increased use of biogas and natural gas is encouraged. To support more effective manufacturing, distribution, and consumption of energy gases, new methods for the measurement of the calorimetric value or the gas composition are needed. In this paper, we present a method to quantify variation in ultrasound pulse shape, caused by interaction effects between the constituents of a two-component gas mixture. The method is based on a combination of principal component analysis and orthogonal signal correction. Experiments on mixtures of oxygen and ethane show that the extracted information correlates well with the molar fraction of ethane in the mixture.

  • 39.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nilsson, M
    Polytechnical University of Catalonia, Barcelona.
    Fernández, E.
    Polytechnical University of Catalonia, Barcelona.
    Planell, J. A.
    Polytechnical University of Catalonia, Barcelona.
    An ultrasonic pulse-echo technique for monitoring the setting of CaSO4-based bone cement2003Ingår i: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 24, nr 1, s. 71-77Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a new ultrasonic technique for monitoring the entire setting process of injectable bone cement. The problem with existing standards is their subjectivity. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that it is non-invasive and non-destructive, since no manipulation of the cement sample is needed once the measurement has started. Furthermore, the results are reproducible with small variations. The testing was performed on calcium sulfate cement using an ultrasonic pulse-echo approach. The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line.

  • 40.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nilsson, M
    Biomaterials Lab, Department of Orthopaedics, Biomedical Centre, Lund.
    Fernández, E
    Research Centre in Biomedical Engineering, Polytechnical University of Catalonia, Barcelona.
    Planell, J. A.
    Research Centre in Biomedical Engineering, Polytechnical University of Catalonia, Barcelona.
    Monitoring the setting of calcium-based bone cements using pulse-echo ultrasound2002Ingår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 13, nr 12, s. 1135-1141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a new technique, based on pulse-echo ultrasound, for monitoring the entire setting process of injectable bone cement. This research has been motivated by the lack of satisfying standards. The main problem with existing standards is the subjectivity, which leads to poor reproducibility. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that if low-intensity ultrasound is used, it provides a non-destructive analysis method. Once the cement paste has been applied to the measurement cell, no manipulation is needed throughout the entire setting process. The problem of the ultrasound affecting the setting of certain cement materials has been investigated, and solutions are discussed. The propagation of ultrasound is temperature-dependent, and therefore a technique for automatic compensation for temperature variations is discussed briefly. The testing was performed on -calcium sulfate hemihydrate (CSH) and mixtures of CSH and -tricalcium phosphate (-TCP). The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line.

  • 41.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nilsson, M.
    Polytechnical University of Catalonia, Barcelona.
    Fernández, E.
    Polytechnical University of Catalonia, Barcelona.
    Planell, J.A.
    Polytechnical University of Catalonia, Barcelona.
    Monitoring the setting of injectable calcium-based bone cements using pulse-echo ultrasound2002Ingår i: Proceedings: 2002 IEEE Ultrasonics Symposium : October 8 - 11, 2002, Forum Hotel, Munich, Germany ; an international symposium / [ed] Donald E. Yuhas, Piscataway, NJ: IEEE Communications Society, 2002, s. 1293-1296Konferensbidrag (Refereegranskat)
    Abstract [en]

    The existing standards for determining the setting time of injectable bone substitutes suffers from poor reproducibility and subjectivity. We previously presented an ultrasonic pulse-echo technique that can follow the entire setting reaction on-line, without any mechanical manipulation of the sample. For calcium sulfate hemihydrate (CSH), the new method shows good agreement with the standards, but with much better reproducibility. One problem with the new technique was its sensitivity to temperature fluctuations. In this paper we present a temperature compensation scheme that automatically corrects the measurements for losses caused by temperature changes. The modified method is verified with experiments on /spl alpha/-tricalcium phosphate (/spl alpha/-TCP). Because /spl alpha/-TCP has longer setting time than CSH, the initial method, which is sensitive to temperature, did not work.

  • 42.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sjöberg, Frank
    Luleå tekniska universitet.
    Simultaneous maximum likelihood estimation of time delay and time scaling2004Ingår i: Norsig 2004: proceedings of the 6th Nordic Signal Processing Symposium : June 9-11, 2004, Espoo, Finland, Helsinki: Helsinki University of Technology , 2004, s. 260-263Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present a simultaneous maximum likelihood estimator (ML) for time delay and time-scaling in the presence of additive white Gaussian Noise. The Cram´er- Rao lower bound for the variance of the estimates is also derived. The performance of the estimator is evaluated for ultrasound echoes for different time-scalings and different time delays. The performance is compared to the standard cross-correlation estimator.

  • 43.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sjöberg, Frank
    Luleå tekniska universitet.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A noise-tolerant group delay estimator applied to dispersion measurement in gases2003Ingår i: Proceedings, 2003 IEEE Ultrasonics Symposium: October 5 - 8, 2003, Hilton Hawaiian Village, Honolulu, Hawaii ; an international symposium / / [ed] Donald E. Yuhas, Piscataway, NJ: IEEE Communications Society, 2003, s. 254-257Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present a model-based group velocity estimator, that can be used to measure speed of sound in ultrasonic pulse-echo systems as a function of ultrasound frequency. The estimation of group velocities involves numerical differentiation of the phase difference. In the presence of noise, this becomes numerically unstable. The model-based approach presented herein, shows better tolerance to experimental noise. The performance of the estimator is evaluated with simulations as function of pulse bandwidth and SNR. Finally, the estimator applied to real data and compared with other methods for measuring speed of sound in Ethane and Oxygen.

  • 44.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sjöberg, Frank
    Luleå tekniska universitet.
    Quieffin, Nicolas
    Laboratoire Ondes et Acoustique, Paris.
    Ing, Ros Kiri
    Laboratoire Ondes et Acoustique, Paris.
    Catheline, Stéfan
    Laboratoire Ondes et Acoustique, Paris.
    Echo-cancellation in a single-transducer ultrasonic imaging system2002Ingår i: NORSIG 2002: 5th Nordic Signal Processing Symposium, Trondheim: The Institute of Electrical and Electronics Engineers , 2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    During the last ten years, time-reversal of acoustic fields have been shown to be a very useful technique in ultrasonic imaging and testing. With the use of transducer arrays, it is possible to steer the sound beam to an arbitrary position within the medium, even if the medium is inhomogeneous or contains scatterers. The major drawback with traditional beamforming and time-reversal techniques is that they require the use of transducer arrays. Recently a new technique was presented that, with the use of a waveguide, makes it possible to focus sound arbitrarily, with only one transducer elements. A problem with the setup is that the signal-to-noise ratio (SNR) is degraded because of interfering echoes from the waveguide. In this paper, we present an echo-cancellation scheme that results in an SNR gain of approximately 33 dB. This enables the new technique to be used in pulse-echo mode, where this was not previously possible.

  • 45.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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.
    In-Situ Monitoring of Particle Velocities and Solids Concentration Variations in wet Low-Intensity Magnetic Separators2015Ingår i: 2015 IEEE International Ultrasonics Symposium, IUS 2015: Taipei, 21-24 Oct. 2015, Piscataway, NJ: IEEE Communications Society, 2015, artikel-id 7329339Konferensbidrag (Refereegranskat)
    Abstract [en]

    In previous work, we have shown how an ultrasound pulse-echo setup can be used to simultaneously measure particle velocity profiles and local solids concentration variations in solid/liquid particle suspensions. In this paper, we demonstrate a real-world case where the system is installed in a wet low-intensity magnetic separator, a process in which magnetic material is separated from gangue. The method was evaluated at LKAB's R&D facilities in Malmberget, Sweden, on one of their pilot scale separators. 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.

  • 46.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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 local solids fraction variations in multiphase flow using pulse-echo ultrasound2015Ingår i: Physics Procedia, ISSN 1875-3892, E-ISSN 1875-3892, Vol. 70, s. 376-379Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an ultrasonic pulse-echo technique for on-line monitoring of variations in solids concentrations in particlesuspensions. The method is based on time-frequency analysis of the backscatter signals, exploring variations in spectral content ofthe backscatter as function of depth in the suspension. Experiments on a settling of magnetite particles in water, at varying solidsconcentrations, show that the settling process can be followed by studying the energy of backscattered ultrasound.

  • 47.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Taavitsainen, Veli-Matti
    EVTEK University of Applied Sciences, Espoo.
    Ultrasonic measurement of the reaction kinetics of the setting of calcium sulfate bone cements using implicit calibration2007Konferensbidrag (Övrigt vetenskapligt)
  • 48.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mohamad, Medhat
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mbit/second Communication through a Rock Bolt Using Ultrasound2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In most industrial processes transfer of data and software from or to sensors is an essential part of the monitoring and control systems. Many of the older, wired communication systems have been or are being replaced with wireless alternatives. A number of challenges are associated with this replacement: Radio receivers are subject to interference from other radio sources. Similarly, radio transmitters may cause undesired interference into other equipment and environments. Compared to wired solutions, security becomes an issue as radio communication links are more vulnerable to eavesdropping than wired schemes. Radio communication with sensors and sensor platforms embedded deep inside large metal structures or fluid tanks may be difficult or even impossible. The objective of this work is to develop and evaluate a high data-rate communications scheme based on ultrasound, which can be used to transmit wirelessly through solid structures. An example will be given using a one-meter segment of a rock bolt.

  • 49.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mohamad, Medhat
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mbit/second Communication through a Rock Bolt Using Ultrasound2017Ingår i: IEEE International Ultrasonics Symposium, IUS, Piscataway, NJ: IEEE Computer Society, 2017, artikel-id 8092474Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a digital communication system based on Orthogonal Frequency Division Multiplexing (OFDM) and MHz-range ultrasound, for transmission of data through solid materials and liquids. The system is tested on experiments using a off-the-shelf ultrasound transducers with a center frequency of 3.5 MHz as transmitter and receiver, respectively. The propagation medium in the experiment was a 1 m long section of an epoxy coated steel rock bolt. The results show that data rates in excess of 1 Mbit/second is attainable, using readily available hardware and software.

  • 50.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    IT som stöd för optimering och energimätning i fjärrvärme- och gasnät2006Konferensbidrag (Övrigt vetenskapligt)
    Abstract [sv]

    Vid EISLAB (Embedded Internet Systems Laboratory), Luleå tekniska universitet, pågår sedan några år tillbaka ett antal projekt kopplade till energimätning. Ett projekt behandlar noggrannhet, diagnostisering och optimering av energimätningar i fjärrvärmenät. Ett annat projekt syftar till att utveckla metoder baserade på ultraljud för mätning av energiflöde och sammansättning av bio- och naturgas. Föredraget ger en sammafattning av det arbete som hittills utförts inom dessa områden samt en framåtblick över de möjligheter och fördelar resultaten från dessa projekt ger i framtiden. Inom fjärrvärmeanvändningen finns ett behov av en förbättrad mätning av energianvändningen, dels för att kunna reglera processerna och dels för att kunder och leverantörer ska betala för rätt saker. Snabb och noggrann mätning är idag inte möjligt. Ur underhållssynpunkt är det även av intresse att på distans kunna diagnosticera systemen, både på leverantörs- och kundsidan. Samma teknik kommer även att kunna användas för optimering av processen. Bio- och naturgas har utpekats som möjliga alternativ till bensin och diesel som drivmedel. De mätmetoder som finns idag för att säkerställa kvaliteten och bestämma energivärdena lämpar sig inte för användning långt ut i distributionskedjan. Målet med forskningsprojektet vid EISLAB är att utveckla en ultraljudsmetod som kan mäta sammansättning, energivärde och flöde av dessa gaser. Fokus ligger på utveckling av statistiska metoder samt fysikaliska modeller för vågutbredning i gaser. Förutom tillämpningar inom bio- och naturgas, kan tekniken även användas inom petrokemisk- och processindustri.

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