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M Nowak, T Tański, P Szperlich, W Matysiak, M Kępińska, D Stróż, Ł Bober, B Toroń
A novel polymeric, polyacrylonitrile (PAN) nanofibers containing ferroelectric and semiconducting antimony sulfoiodide (SbSI) have been made by electrospinning. SbSI nanowires, used as the filler, have been prepared sonochemically from antimony sulphide (Sb2S3) and antimony tri-iodide (SbI3) for the first time. Nanocrystalline SbSI has been fabricated in ethanol under ultrasonic irradiation (20kHz, 565W/cm(2)) at 323K within 2h. The products have been characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction and optical diffuse reflection as well as transmission spectroscopy...
September 2017: Ultrasonics Sonochemistry
Mami Matsukawa, Sayaka Matsukawa
OBJECTIVE: It is well known that applied stress induces electrical potentials in bone. We have experimentally studied whether induced potentials could be found in bone using an ultrasound irradiation system similar to low-intensity pulsed ultrasound (LIPUS). MATERIALS AND METHODS: Circular plate specimens (diameter 10 mm, thickness 1 mm) were obtained from bovine femora in order to determine if bone behaved as a piezoelectric material. Using these specimens, ultrasound receivers were fabricated...
July 2017: Journal of Orthopaedic Trauma
Yousra Nahas, Alireza Akbarzadeh, Sergei Prokhorenko, Sergey Prosandeev, Raymond Walter, Igor Kornev, Jorge Íñiguez, L Bellaiche
In light of directives around the world to eliminate toxic materials in various technologies, finding lead-free materials with high piezoelectric responses constitutes an important current scientific goal. As such, the recent discovery of a large electromechanical conversion near room temperature in (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 compounds has directed attention to understanding its origin. Here, we report the development of a large-scale atomistic scheme providing a microscopic insight into this technologically promising material...
June 20, 2017: Nature Communications
Yan Fang, Victor V Yashin, Steven P Levitan, Anna C Balazs
Inspired by the advances in both materials and computer science, we describe efforts to design "materials that compute" where the material and the computer are the same entity. Using theory and simulation, we devise systems that integrate the behavior of self-oscillating gels and fundamental concepts from oscillator-based computing. We specifically focus on gels that undergo the Belousov-Zhabotinsky (BZ) reaction and thus exhibit self-sustained oscillations. In our models, we couple the BZ gel to an overlaying piezoelectric (PZ) cantilever to create a BZ-PZ unit...
June 20, 2017: Chemical Communications: Chem Comm
Pradeep Ramiah Rajasekaran, Chuanhong Zhou, Mallika Dasari, Kay-Obbe Voss, Christina Trautmann, Punit Kohli
A new lithographic editing system with an ability to erase and rectify errors in microscale with real-time optical feedback is demonstrated. The erasing probe is a conically shaped hydrogel (tip size, ca. 500 nm) template-synthesized from track-etched conical glass wafers. The "nanosponge" hydrogel probe "erases" patterns by hydrating and absorbing molecules into a porous hydrogel matrix via diffusion analogous to a wet sponge. The presence of an interfacial liquid water layer between the hydrogel tip and the substrate during erasing enables frictionless, uninterrupted translation of the eraser on the substrate...
June 2017: Science Advances
Yanhao Yu, Haiyan Sun, Hakan Orbay, Feng Chen, Christopher G England, Weibo Cai, Xudong Wang
The rapid developments of implantable biomedical electronics give rise to the motivation of exploring efficient and durable self-powered charging system. In this paper, we report a mesoporous polyvinylidene fluoride (PVDF)-based implantable piezoelectric nanogenerator (NG) for in vivo biomechanical energy harvesting. The NG was built with a sponge-like mesoporous PVDF film and encapsulated by polydimethylsiloxane (PDMS). After embedding this NG into rodents, a Voc of ~200 mV was produced from the gentle movement of rodent muscle...
September 2016: Nano Energy
P José Gouveia, S Rosa, L Ricotti, B Abecasis, H V Almeida, L Monteiro, J Nunes, F Sofia Carvalho, M Serra, S Luchkin, A Leonidovitch Kholkin, P Marques Alves, P Jorge Oliveira, R Carvalho, A Menciassi, R Pires das Neves, L Silva Ferreira
The use of engineered cardiac tissue for high-throughput drug screening/toxicology assessment remains largely unexplored. Here we propose a scaffold that mimics aspects of cardiac extracellular matrix while preserving the contractility of cardiomyocytes. The scaffold is based on a poly(caprolactone) (PCL) nanofilm with magnetic properties (MNF, standing for magnetic nanofilm) coated with a layer of piezoelectric (PIEZO) microfibers of poly(vinylidene fluoride-trifluoroethylene) (MNF+PIEZO). The nanofilm creates a flexible support for cell contraction and the aligned PIEZO microfibers deposited on top of the nanofilm creates conditions for cell alignment and electrical stimulation of the seeded cells...
September 2017: Biomaterials
Raad Haleoot, Charles Paillard, Thaneshwor P Kaloni, Mehrshad Mehboudi, Bin Xu, L Bellaiche, Salvador Barraza-Lopez
Photostriction is predicted for group-IV monochalcogenide monolayers, two-dimensional ferroelectrics with rectangular unit cells (the lattice vector a_{1} is larger than a_{2}) and an intrinsic dipole moment parallel to a_{1}. Photostriction is found to be related to the structural change induced by a screened electric polarization (i.e., a converse piezoelectric effect) in photoexcited electronic states with either p_{x} or p_{y} (in-plane) orbital symmetry that leads to a compression of a_{1} and a comparatively smaller increase of a_{2} for a reduced unit cell area...
June 2, 2017: Physical Review Letters
Bita Rohani, Mehrdad Barekatain, Shirin Z Farhad, Navid Haghayegh
INTRODUCTION: In cervical lesions, various restorative materials can be inserted, which can be affected by the application of periodontal scalers. This study evaluated and compared the marginal seal of class V glass ionomer, composite resin, and amalgam restorations after subjecting them to hand instrumentation and ultrasonic scaling. MATERIALS AND METHODS: In this experimental study, 30 sound human first premolars were selected. In each tooth, buccal and lingual cavities (4 mm mesiodistal width, 3 mm occlusogingival height, and 2 mm depth) were made...
June 1, 2017: Journal of Contemporary Dental Practice
Ianis Bernard, Alexander A Doinikov, Philippe Marmottant, David Rabaud, Cédric Poulain, Pierre Thibault
We show experimental evidence of the acoustically-assisted micromanipulation of small objects like solid particles or blood cells, combining rotation and translation, using high frequency surface acoustic waves. This was obtained from the leakage in a microfluidic channel of two standing waves arranged perpendicularly in a LiNbO3 piezoelectric substrate working at 36.3 MHz. By controlling the phase lag between the emitters, we could, in addition to translation, generate a swirling motion of the emitting surface which, in turn, led to the rapid rotation of spherical polystyrene Janus beads suspended in the channel and of human red and white blood cells up to several rounds per second...
June 15, 2017: Lab on a Chip
Hiroyuki Takenaka, Ilya Grinberg, Shi Liu, Andrew M Rappe
Despite more than 50 years of investigation, it is still unclear how the underlying structure of relaxor ferroelectrics gives rise to their defining properties, such as ultrahigh piezoelectric coefficients, high permittivity over a broad temperature range, diffuse phase transitions, strong frequency dependence in dielectric response, and phonon anomalies. The model of polar nanoregions inside a non-polar matrix has been widely used to describe the structure of relaxor ferroelectrics. However, the lack of precise knowledge about the shapes, growth and dipole patterns of polar nanoregions has led to the characterization of relaxors as "hopeless messes", and no predictive model for relaxor behaviour is currently available...
June 14, 2017: Nature
Juan Melchor, Rafael Muñoz, Guillermo Rus
Torsion mechanical waves have the capability to characterize shear stiffness moduli of soft tissue. Under this hypothesis, a computational methodology is proposed to design and optimize a piezoelectrics-based transmitter and receiver to generate and measure the response of torsional ultrasonic waves. The procedure employed is divided into two steps: (i) a finite element method (FEM) is developed to obtain a transmitted and received waveform as well as a resonance frequency of a previous geometry validated with a semi-analytical simplified model and (ii) a probabilistic optimality criteria of the design based on inverse problem from the estimation of robust probability of detection (RPOD) to maximize the detection of the pathology defined in terms of changes of shear stiffness...
June 15, 2017: Sensors
Guofeng Lou, Xinjie Yu, Shihua Lu
This paper describes the modeling of magnetoelectric (ME) effects for disk-type Terfenol-D (Tb0.3Dy0.7Fe1.92)/PZT (Pb(Zr,Ti)O₃) laminate composite at low frequency by combining the advantages of the static elastic model and the equivalent circuit model, aiming at providing a guidance for the design and fabrication of the sensors based on magnetoelectric laminate composite. Considering that the strains of the magnetostrictive and piezoelectric layers are not equal in actual operating due to the epoxy resin adhesive bonding condition, the magnetostrictive and piezoelectric layers were first modeled through the equation of motion separately, and then coupled together with a new interface coupling factor kc, which physically reflects the strain transfer between the phases...
June 15, 2017: Sensors
Pedro Castro, Luis Elvira, Juan Ramón Maestre, Francisco Montero de Espinosa
This work analyzes some key aspects of the behavior of sensors based on piezoelectric Thickness Shear Mode (TSM) resonators to study and monitor microbial biofilms. The operation of these sensors is based on the analysis of their resonance properties (both resonance frequency and dissipation factor) that vary in contact with the analyzed sample. This work shows that different variations during the microorganism growth can be detected by the sensors and highlights which of these changes are indicative of biofilm formation...
June 15, 2017: Sensors
Nur Amin Hoque, Pradip Thakur, Swagata Roy, Arpan Kool, Biswajoy Bagchi, Prosenjit Biswas, Md Minarul Saikh, Farha Khatun, Sukhen Das, Partha Pratim Ray
Design of energy harvesting unit with superior output characteristics i.e. high power density is of great technological challenge in the present time. Here, a simple, light weight, flexible and cost effective piezoelectric nanogenerators (PENGs) have been fabricated integrating the aluminum electrodes on to Er3+/ Fe3+ stimulated electroactive, visible light emitting and large dielectric PVDF films where ErCl3. 6H2O and Fe(NO3)3 · 9H2O act as the catalytic agents for electroactive β polymorph nucleation and enhancement of dielectric properties...
June 14, 2017: ACS Applied Materials & Interfaces
Jinzhen Fan, Fernando Villarreal, Brent Weyers, Yunfeng Ding, Kuo Hao Tseng, Jiannan Li, Baoqing Li, Cheemeng Tan, Tingrui Pan
Natural genetic promoters are regulated by multiple cis and trans regulatory factors. For quantitative studies of these promoters, the concentration of only a single factor is typically varied to obtain the dose response or transfer function of the promoters with respect to the factor. Such design of experiments has limited our ability to understand quantitative, combinatorial interactions between multiple regulatory factors at promoters. This limitation is primarily due to the intractable number of experimental combinations that arise from multifactorial design of experiments...
June 14, 2017: Lab on a Chip
Junhong Li, Wei Ren, Guoxiang Fan, Chenghao Wang
A square piezoelectric composite diaphragm was analyzed by the finite element method to enhance the sensitivity of a piezoelectric micromachined ultrasound transducer (pMUT). The structures of electrode and piezoelectric film were optimized and a centric electrode was designed to avoid the counteraction of stress in the centre and edges. In order to further improve the sensitivity; a pMUT with partially-etched piezoelectric film was adopted. The receive and transmit sensitivities of the pMUT were analyzed in details...
June 14, 2017: Sensors
Gian Nutal Schädli, Robert Büchel, Sotiris E Pratsinis
Lead-free piezoelectric nanogenerators made with BaTiO3 offer an attractive energy harvesting solution towards portable, battery-free medical devices such as self-powered pacemakers. Here, we assembled nanogenerators made of thin, flexible poly(vinylidene fluoride-co-hexafluoropropylene) films containing either polycrystalline BaTiO3 nanoparticles of various sizes or commercial monocrystalline particles of 64 or 278 nm in average diameter. The nanoparticles were prepared by hydrogen-driven flame aerosol technology and had an average diameter of 24-50 nm with an average crystal size of about 10 nm...
July 7, 2017: Nanotechnology
Manali Datta, Dignya Desai, Ashok Kumar
Gene specific DNA based sensors have potential applications for rapid and real time monitoring of hybridization signal with the target nucleic acid of pathogens. Different types of DNA based sensors and their applications have been studied for rapid and accurate detection of pathogens causing human diseases. These sensors are based on surface plasmon resonance, quantum-dots, molecular beacons, piezoelectric and electrochemical etc. Curbing epidemics at an early stage is one of the massive challenges in healthcare systems...
June 2017: Indian Journal of Microbiology
M Celmer, K J Opieliński, M Dopierała
One of the reasons of distortions in ultrasonic imaging are crosstalk effects. They can be divided into groups according to the way of their formation. One of them is constituted by mechanical crosstalk, which is propagated by a construction of a multi-element array of piezoelectric transducers. When an individual transducer is excited, mechanical vibrations are transferred to adjacent construction components, thereby stimulating neighboring transducers to an undesired operation. In order to explore ways of the propagation of such vibrations, the authors developed the FEM model of the array of piezoelectric transducers designed for calculations in COMSOL Multiphysics software...
June 3, 2017: Ultrasonics
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