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David Alaluf, Renaud Bastaits, Kainan Wang, Mihaita Horodinca, Grégory Martic, Bilal Mokrani, André Preumont
This paper presents a unimorph deformable mirror intended to be used as secondary corrector in space telescopes. The deformable mirror consists of a single-crystal silicon wafer (76.2 mm diameter, 500 μm thickness) covered with an optical coating on the front side and an array of 25 independent piezoelectric transducer (PZT) actuators acting in d31 mode on the back side. The mirror is mounted on an isostatic support with three position linear actuators controlling the rigid-body motion. The first part of the paper presents the experimental results obtained with the manufactured prototype...
May 10, 2018: Applied Optics
Dharmendra Kumar Soni, Rafiq Ahmad, Suresh Kumar Dubey
The early detection of Listeria monocytogenes (L. monocytogenes) and understanding the disease burden is of paramount interest. The failure to detect pathogenic bacteria in the food industry may have terrible consequences, and poses deleterious effects on human health. Therefore, integration of methods to detect and trace the route of pathogens along the entire food supply network might facilitate elucidation of the main contamination sources. Recent research interest has been oriented towards the development of rapid and affordable pathogen detection tools/techniques...
May 23, 2018: Critical Reviews in Microbiology
Jiawei Zhou, Albert Kim, Babak Ziaie
In this paper, we present an ultrasonically controlled switching system that can save the battery power for implantable devices by turning the system on and off, on-demand. Ultrasonic control is employed to reduce the device size, increase the penetration depth, and reduce misalignment sensitivity associated with alternative techniques using permanent magnet and RF signal. As a proof-of-concept demonstration, a 665 kHz ultrasonic signal is used to activate a piezoelectric receiver which in turn switches a battery-powered RF system on-and-off...
May 23, 2018: Biomedical Microdevices
Hyun-Young Lee, Jin Luo, Zhen Zhou, Wei Sun, Jing-Feng Li
High-quality (1 - x)(Bi0.5Na0.5)TiO3-xSrTiO3 lead-free piezoelectric thin films (x = 0, 0.1, and 0.25) on Pt(111)/Ti/SiO2/Si(100) substrates were prepared by a sol-gel method. The microstructures of the thin films as a function of SrTiO3 doping level and temperature were investigated by X-ray diffraction and Raman spectroscopy. Their temperature- and frequency-dependent piezoelectric properties were studied on the nanoscale using switching spectroscopy piezoresponse force microscopy (SS-PFM). A rhombohedral ferroelectric to pseudocubic relaxor phase transition was observed when either ST content or temperature increased...
May 23, 2018: Physical Chemistry Chemical Physics: PCCP
José Cardoso, Filipe F Oliveira, Mariana P Proenca, João Ventura
With the consistent shrinking of devices, micro-systems are, nowadays, widely used in areas such as biomedics, electronics, automobiles, and measurement devices. As devices shrunk, so too did their energy consumptions, opening the way for the use of nanogenerators (NGs) as power sources. In particular, to harvest energy from an object's motion (mechanical vibrations, torsional forces, or pressure), present NGs are mainly composed of piezoelectric materials in which, upon an applied compressive or strain force, an electrical field is produced that can be used to power a device...
May 22, 2018: Nanomaterials
Shijun Zheng, Enxiu Wu, Zhihong Feng, Rao Zhang, Yuan Xie, Yuanyuan Yu, Rui Zhang, Quanning Li, Jing Liu, Wei Pang, Hao Zhang, Daihua Zhang
We developed a new way to enhance the photoresponsivity of a van der Waals heterojunction p-n diode using surface acoustic waves (SAWs). The diode was constructed on top of a piezoelectric LiNbO3 substrate and composed of p-type black phosphorus (BP) and n-type molybdenum disulfide (MoS2) flakes that partly overlapped with each other. This layout facilitated the applied SAWs to rapidly drive carriers out of the depletion region. In this structural design, SAWs promoted the separation of photogenerated carriers, and thus greatly increased the photocurrent...
May 22, 2018: Nanoscale
Alexandre De Neef, Cédric Samuel, Grégory Stoclet, Mohamed Rguiti, Christian Courtois, Philippe Dubois, Jérémie Soulestin, Jean-Marie Raquez
Poly(vinylidene difluoride) (PVDF) displays attractive ferroelectric/piezoelectric properties and its polar β-crystals are specifically targeted for achieving electroactive applications. However, their direct crystallization from the melt state represents a challenging task that has never been addressed using melt-state processes. The use of poly(methyl methacrylate) (PMMA) is herein investigated to promote the PVDF polar β-phase using melt-blending and extrusion-calendering technologies. The presence of the β-phase is here confirmed by ATR-FTIR and WAXS experiments with blends at a PMMA content as low as 5 wt%...
May 22, 2018: Soft Matter
Evgenia Gilshteyn, Daler Amanbaev, Maxim Silibin, Artem Sysa, Vladislav Kondrashov, Anton Anisimov, Tanja Kallio, Albert Nasibulin
The integration of the energy harvesting and energy storage in a single device both enables the conversion of the ambient energy into electricity and provides a sustainable power source for various electronic devices and systems. On the other hand, mechanical flexibility coupled with optical transparency of the energy storage devices is required for many applications, ranging from self-powered rolled-up displays to wearable optoelectronic devices. We integrate a piezoelectric poly(vinylidene-trifluoroethylene) film into a flexible supercapacitor system to harvest and store the energy...
May 21, 2018: Nanotechnology
Parikshit Sahatiya, Akash Shinde, Sushmee Badhulika
Even though 2D ZnO has been utilized for enhanced self-powered sensing by strain modulation due to its piezoelectric property, study on utilizing pyroelectric property of ZnO remains unexplored. The piezoelectric property of 2D ZnO works on mechanical strain which disrupts the structure of ZnO leading to the failure of device. For pyroelectric nanogenerator, temperature difference can be triggered by external light source which does not disrupt the ZnO structure and also avoids the need for physical bending/pressing as in case of piezoelectric nanogenerator...
May 21, 2018: Nanotechnology
Yoshiaki Tanaka, Shoji Okamoto, Kazuya Hashimoto, Ryoichi Takayama, Takakiyo Harigai, Hideaki Adachi, Eiji Fujii
Here, we demonstrate the high electromechanical strain and enhanced temperature characteristics in the c-axis-oriented lead-free (Na,Bi)TiO3 -BaTiO3 (NBT-BT) polycrystalline thin film prepared on Si substrates by rf magnetron sputtering. The effective transverse piezoelectric coefficient, e31 * , estimated from the electromechanical strain measured under high electric field, reaches a high level of -12.5 C/m2 , and is comparable to those of conventional Pb(Zr,Ti)O3 films. In-situ X-ray diffraction measurement and electron diffraction analysis revealed the electromechanical strain of the NBT-BT film to originate predominantly in elongation of the tetragonal (P4bm) crystal lattice in the c-axis direction...
May 18, 2018: Scientific Reports
Shen Liang, Wang Chaohui
In this paper, a model for the radiation force exerted by standing surface acoustic waves (SSAWs) on a rigid cylinder in inviscid fluids is extended to account for the dependence on the Rayleigh angle. The conventional model for the radiation force used in the SSAW-based applications is developed in plane standing waves, which fails to predict the movement of the cylinder in the SSAW. Our revised model reveals that, in the direction normal to the piezoelectric substrate on which the SSAW is generated, acoustic radiation force can be large enough to drive the cylinder even in the long-wavelength limit...
March 2018: Physical Review. E
William S Enns-Bray, Stephen J Ferguson, Benedikt Helgason
There is currently a knowledge gap in scientific literature concerning the strain rate dependent properties of trabecular bone at intermediate strain rates. Meanwhile, strain rates between 10 and 200/s have been observed in previous dynamic finite element models of the proximal femur loaded at realistic sideways fall speeds. This study aimed to quantify the effect of strain rate (ε̇) on modulus of elasticity (E), ultimate stress (σu ), failure energy (Uf ), and minimum stress (σm ) of trabecular bone in order to improve the biofidelity of material properties used in dynamic simulations of sideways fall loading on the hip...
May 3, 2018: Journal of Biomechanics
Sara Soheilifar, Mohsen Bidgoli, Ehsan Houshyar, Maryam Farhadian, Ali Ghamari
The objective of this study was to compare the effects of preparing for implant site osteotomy with conventional drilling or piezosurgery on the stability of oral implants after a 5 month follow-up period. Thirty patients participated in this randomized clinical trial and received two implants in posterior mandible in bone of the same quality. All surgical procedures were performed by the same surgeon. Implant stability amounts were measured by resonance frequency analysis using the Osstell Mentor device and are reported in the format of implant stability quotient (ISQ) values at baseline and 90 and 150 days after surgery...
2018: Journal of Long-term Effects of Medical Implants
Shuli Fan, Shaoyu Zhao, Baoxin Qi, Qingzhao Kong
One of the major causes of damage to column-supported concrete structures, such as bridges and highways, are collisions from moving vehicles, such as cars and ships. It is essential to quantify the collision damage of the column so that appropriate actions can be taken to prevent catastrophic events. A widely used method to assess structural damage is through the root-mean-square deviation (RMSD) damage index established by the collected data; however, the RMSD index does not truly provide quantitative information about the structure...
May 17, 2018: Sensors
Abdul Hafiz Alameh, Mathieu Gratuze, Mohannad Y Elsayed, Frederic Nabki
Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e...
May 16, 2018: Sensors
Cheng-Tang Pan, Chung-Kun Yen, Shao-Yu Wang, Shih-Kang Fan, Fong-Yi Ciou, Liwei Lin, J C Huang, Shiao-Wei Kuo
This paper describes the application of piezoelectric fibers and films formed using near-field electrospinning (NFES) and electrospray (ESP) technology. Poly(γ-methyl L-glutamate) (PMLG), a biocompatible material, was mixed with poly(ethylene oxide) (PEO) and surfactant to obtain a solution of appropriate viscosity and conductance. Because the orientation of the dipoles in PMLG was enhanced upon applying an electric field, we could use the NFES and ESP processes to align dipoles and enhance the piezoelectric properties of the resulting fibrous materials...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Giuseppe Giannaccare, Aldo Vagge, Stefano Sebastiani, Lara E Urbini, Paolo Corazza, Marco Pellegrini, Luciana Carmassi, Fulvio Bergamini, Carlo E Traverso, Emilio C Campos
PURPOSE: The aim of this study was to evaluate the safety and efficacy of ultrasound cyclo-plasty (UCP) for reducing intraocular pressure (IOP) in patients with glaucoma. METHODS: This is a multicentre prospective study conducted in 3 Italian glaucoma centres. UCP was performed by EyeOP1, which delivers ultrasound beams using 6 piezoelectric transducers activated for 4/6 s (first generation) or 8 s (second generation). Primary outcomes were the mean IOP reduction and the rates of success after 1 year...
May 16, 2018: Ophthalmic Research
Z Bi, W Cai, Y Wang, G Shang
Micro/nanomanipulation is a rapidly growing technology and holds promising applications in various fields, including photonic/electronic devices, chemical/biosensors etc. In this work, we present that shear force microscopy (ShFM) can be exploited to manipulate metallic nanosheets besides imaging. The manipulation is realized via controlling the shear force sensor probe position and shear force magnitude based on our homemade ShFM system under an optical microscopy for in situ observation. The main feature of the ShFM system is usage of a piezoelectric bimorph sensor, which has the ability of self-excitation and detection...
May 15, 2018: Journal of Microscopy
Jhonatan Camacho Navarro, Magda Ruiz, Rodolfo Villamizar, Luis Mujica, Jabid Quiroga
This work discusses the advantage of using cross-correlation analysis in a data-driven approach based on principal component analysis (PCA) and piezodiagnostics to obtain successful diagnosis of events in structural health monitoring (SHM). In this sense, the identification of noisy data and outliers, as well as the management of data cleansing stages can be facilitated through the implementation of a preprocessing stage based on cross-correlation functions. Additionally, this work evidences an improvement in damage detection when the cross-correlation is included as part of the whole damage assessment approach...
May 15, 2018: Sensors
Jicheng Zhang, Yongshui Huang, Yu Zheng
In recent years, piezoelectric-based transducers and technologies have made significant progress towards structural health monitoring and damage evaluation for various metal and concrete structures. Timber is still commonly used as a construction material in practical engineering; however, there is a lack of research on the health monitoring of timber-based structures using piezoelectric-based transducers and methods. This paper conducts a feasibility study on timber damage detection using surface-mounted piezoelectric patches, which enable the stress-wave-based active sensing approach...
May 15, 2018: Sensors
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