Abstract
Nano fiber feels forces, hears sounds made by cells
Engineers at the University of California San Diego have developed a miniature device that is sensitive enough to feel the forces generated by swimming bacteria and hear the beating of heart muscle cells.
The device is a nano-sized optical fiber that is about 100 times thinner than a human hair. It can detect forces down to 160 fN—about 10 trillion times smaller than a newton—when placed in a solution containing live Helicobacter pylori bacteria, which are swimming bacteria found in the gut. In cultures of beating heart muscle cells from mice, the nano fiber can detect sounds down to −30 dB—a level that is 1000 times below the limit of the human ear.
“This work could open up new doors to track small interactions and changes that couldn’t be tracked before,” said nanoengineering professor Donald Sirbuly at the UC San Diego Jacobs School of Engineering, who led the study.
For more information, follow the link: https://www.sciencedaily.com/releases/2017/05/170515111619.htm
Sound waves boost older adults’ memory, deep sleep
Gentle sound stimulation—such as the rush of a waterfall—synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and improved their ability to recall words, reports a new Northwestern Medicine study.
Deep sleep is critical for memory consolidation. But beginning in middle age, deep sleep decreases substantially, which scientists believe contributes to memory loss in aging. The sound stimulation significantly enhanced deep sleep in participants and their scores on a memory test.
“This is an innovative, simple and safe non-medication approach that may help improve brain health,” said senior author Dr Phyllis Zee, professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine sleep specialist. “This is a potential tool for enhancing memory in older populations and attenuating normal age-related memory decline.”
For more information, follow the link: https://www.sciencedaily.com/releases/2017/03/170308081024.htm
Complex damping treatments—frequency domain modeling and testing
Frequency domain modeling and testing, with a focus on complex damping treatments, both acoustic damping materials (poroelastic) and structural damping materials (viscoelastic) in single- or multi-layered configurations, is the focus of this research topic. Both development of efficient modeling techniques and the development of high-fidelity numerical models serve a model-based toolchain that is instrumental in characterization of material and other relevant parameters in an inverse way.
For more information, follow the link: http://www.mech.kuleuven.be/en/research/mod/research/vibroacoustics
Simulation of time-harmonic acoustic problems with maximum-entropy meshfree methods
Time harmonic acoustic problems are simulated with local maximum-entropy (LME) meshfree approximants. LME approximants are computed considering an equivalence between basis functions and discrete probability distributions and applying the max-ent formalism developed by Jaynes in statistical mechanics. The character of LME approximants allows them to improve the results of standard finite elements especially in the high-frequency region, where the pollution effect is significantly reduced. This is particularly relevant for the simulation of short wavelengths problems, which are still a challenge for classical finite elements formulations. Furthermore, LME approximants can be blended with isogeometric analysis on the boundary of the domain, which gives a higher geometric accuracy to the method.
For more information, follow the link: http://www.mech.kuleuven.be/en/research/mod/research/vibroacoustics
Numerical methods for acoustic wave propagation through non-homogeneous flow regions
The research work focuses on the development of numerical methods to predict accurately the acoustic wave propagation through non-homogeneous flow regions, accounting for the various convective and dissipative phenomena. Both hybrid linear acoustic solvers and computational fluid dynamics approaches are applied to the case of passive acoustic dampers with perforations, like Helmholtz resonators and perforated panels, to develop reliable acoustic impedance models and investigate the involved physics.
For more information, follow the link: http://www.mech.kuleuven.be/en/research/mod/research/aero-acoustics
Acoustic and vibration condition monitoring of bearings and defect size estimation
Rolling element bearings are used extensively in rotating machinery in a vast number of industries, from mining to aerospace. However, bearings have a finite life and eventually start to develop surface defects on the rolling elements or on the inner or outer raceways. These defects increase the vibrations generated by the bearing, causing increased noise and vibrations emitted from the system. If the damaged bearing is not rectified, failure of the bearing and/or failure of other components will occur. Any malfunction of a bearing can cause costly down time and/or catastrophic failures that could result in the loss of human life, for example, a train derailing due to a seized bearing. The principle aim of the project is to develop the necessary signal processing methods to estimate the size of a defect within a bearing. This is being achieved through the development of a multi-modal model, and experimental data acquired from damaged bearings.
For more information, follow the link: https://mecheng.adelaide.edu.au/avc/projects/projectabstract.php?UID=72
Investigation of the effect of wake interaction on wind farm noise emission
In a wind farm, which consist of arrays of turbines, the interaction of the downstream turbines with the wakes from the upstream turbines results in a reduction of the overall wind farm performance. In addition, turbine wakes are an inherent source of turbulence, which exert fluctuating loads on the blades of the downstream turbines. These fluctuating loads and increased turbulence intensity can cause the generation of noise and fatigue on the turbine’s blades. This study focuses on wind turbine wake development, its interaction with the downstream turbines, and its overall effect on wind farm noise signature using numerical and experimental methods.
For more information, follow the link: https://mecheng.adelaide.edu.au/avc/projects/projectabstract.php?UID=81
Foldable, origami-inspired acoustic arrays for large, simple, and real-time guidance of wave energy
Focused acoustic energies are the fuel for numerous scientific and engineering applications including biomedical and scientific imaging, non-lethal force projection, signal and message transmission, and acoustic environment simulation, to name a few. A traditional method of providing the needed real-time adaptation of acoustic energy focus is to use digital signal processing methods, although these methods introduce unique challenges in complexity, stability, portability, and computational cost. To bypass such challenges, we are integrating principles from structural acoustics and reconfigurable origami to establish a new approach of foldable tessellated acoustic structures for significant, easy, real-time beaming of acoustic energy. Through analytical, numerical, and experimental efforts, our studies are investigating the relationships between tessellated transducer architectures and the resulting sound field transformations in consequence to folding such systems. The new framework we are creating will cultivate new ideas for easily adaptive microphone arrays, sound absorbers, ultrasonic transducers, and more.
For more information, follow the link: https://lsvr.osu.edu/research