A5047116846- Ultrasonics and Acoustic Wave Propagation
- Ultrasound Imaging and Elastography
- Bone health and osteoporosis research
- Photoacoustic and Ultrasonic Imaging
- Geophysical Methods and Applications
- Ultrasound and Hyperthermia Applications
- Non-Destructive Testing Techniques
- Bone fractures and treatments
- Hip and Femur Fractures
- Microwave Imaging and Scattering Analysis
- Body Composition Measurement Techniques
- Cerebral Palsy and Movement Disorders
- Muscle activation and electromyography studies
- Ultrasound and Cavitation Phenomena
- Lower Extremity Biomechanics and Pathologies
- Thermography and Photoacoustic Techniques
- Balance, Gait, and Falls Prevention
- Dental Implant Techniques and Outcomes
- Seismic Imaging and Inversion Techniques
- Optical Coherence Tomography Applications
- Advanced Antenna and Metasurface Technologies
- Hydraulic Fracturing and Reservoir Analysis
- Adipose Tissue and Metabolism
- Therapeutic Uses of Natural Elements
- Material Properties and Failure Mechanisms
Helsinki Institute of Physics
2017-2022
University of Helsinki
2017-2022
University of Oulu
2017
University of Jyväskylä
2007-2017
Hôpital Lariboisière
2007
Sorbonne Université
2006-2007
Centre National de la Recherche Scientifique
2006-2007
Recent progress in quantitative ultrasound (QUS) has shown increasing interest toward measuring long bones by ultrasonic guided waves. This technology is widely used the field of nondestructive testing and evaluation different waveguide structures. Cortical bone provides such an elastic its ability to sustain loading resist fractures known be related mechanical properties at length scales. Because waves could yield diverse characterizations bone's macroscopic level, method a strong potential...
Ultrasonic Lamb modes typically propagate as a combination of multiple dispersive wave packets. Frequency components each mode distribute widely in time domain due to dispersion and it is very challenging separate individual by traditional signal processing methods. In the present study, method compensation proposed for purpose separation. This numerical compensates, i.e., compresses, waveforms into temporal pulses, which thereby become nearly un-overlapped frequency can thus be extracted...
Existing ultrasound devices for assessing the human tibia are based on detecting first arriving signal, corresponding to a wave propagating at, or close to, bulk longitudinal velocity in bone. However, long bones effectively irregular hollow tubes and should theoretically support propagation of more complex guided modes similar Lamb waves plates. Guided attractive because they propagate throughout bone thickness can potentially yield information material properties architecture. In this...
It was reported in a previous study that simulated guided wave axial transmission velocities on two-dimensional (2D) numerically reproduced geometry of long bones predicted moderately real vitro ultrasound data the same bone samples. also shown fitting velocity with simple analytical model yielded precise estimate (UTh) for true cortical thickness. This current expands 2D into three dimensions (3D). To this end, and UTh were determined from experiments time-domain finite-difference...
Recent in vitro and simulation studies have shown that guided waves measured at low ultrasound frequencies (f=200 kHz) can characterize both material properties geometry of the cortical bone wall. In particular, a method for an accurate thickness estimation from velocity data has been presented. The clinical application remains, however, challenge as impact layer soft tissue on top is not yet well established, this expected to affect dispersion relative intensities modes. present study...
Previously it has been demonstrated that cortical bone thickness can be estimated from ultrasonic guided-wave measurements, in an axial transmission configuration, together with appropriate analytical model. This study considers the impact of variation within measurement region on ultrasonically determined (UTh). To this end, wave velocities and UTh were experiments time-domain finite-difference simulations propagation, both performed a set ten human radius specimens (29 sites). A...
The goal of this work was to show that a non-absorbing free plate model can predict with reasonable accuracy guided modes measured in bone-mimicking phantoms have circular cross-section. Experiments were carried out on uncoated and coated using clinical axial transmission setup. Adjustment the experimental data yielded estimates for waveguide characteristics (thickness, bulk wave velocities). Fair agreement achieved over frequency range 0.4 1.6 MHz. A lower observed thinnest caused by...
Ultrasound provides a way to clean fouled pipes in industrial settings without interrupting the production. Ultrasonic clamp-on cleaners are used pipes, but they typically cannot focus cleaning power. This leads insufficient results cases where fouling is localized certain parts of pipe. To solve this issue, we propose finite-element method -based time-reversal (FEM-TR) technique for controlling acoustic field produced by an ultrasonic cleaner. We demonstrate simulations and experimental...
Objective: To evaluate the effects of a low-frequency sound wave therapy programme on functional capacity, blood circulation and bone metabolism frail elderly. Design: Single-blind, randomized, controlled trial. Setting: Two senior service centres. Subjects: Forty-nine volunteers (14 males 35 females) aged 62—93 years with up to 12 diagnosed diseases were allocated in either intervention group (n = 30) or control 19). Intervention: The underwent therapy, 3—5 times week for 30 minutes per...
Selecting and tuning modes are useful in ultrasonic guided wave non-destructive testing (NDT) since certain at various center frequencies sensitive to specific types of defects. Ideally one should be able select both the mode frequency launched waves. We demonstrated that an affordable laser diode array can selectively launch either S0 or A0 a chosen into polymer plate. A fiber-coupled (4 elements) illuminated 2 mm thick acrylic predetermined time delay matching selected was employed between...
Recent progress in quantitative ultrasound (QUS) has shown increasing interest towards measuring long bones by ultrasonic guided waves. This technology is widely used the field of non-destructive testing and evaluation different waveguide structures. Cortical bone provides such an elastic its ability to sustain loading resist fractures known relate mechanical properties at length scales. As waves could yield diverse characterization bone's macroscopic level, method a strong potential over...
Pipe fouling is a challenging problem in many industrial applications. Current cleaning techniques require halting the production during phase and existing methods are unable to do targeted cleaning, even though often localized certain areas inside pipeline. To address this issue, we use FEM-simulated, time-reversed signals focus ultrasound power onto pre-determined location: fouled pipe residing Plexiglas container. Ultrasound with similar acoustic was compared time-reversal enhanced method...