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https://www.readbyqxmd.com/read/28335385/patient-posture-monitoring-system-based-on-flexible-sensors
#1
Youngsu Cha, Kihyuk Nam, Doik Kim
Monitoring patients using vision cameras can cause privacy intrusion problems. In this paper, we propose a patient position monitoring system based on a patient cloth with unobtrusive sensors. We use flexible sensors based on polyvinylidene fluoride, which is a flexible piezoelectric material. Theflexiblesensorsareinsertedintopartsclosetothekneeandhipoftheloosepatientcloth. We measure electrical signals from the sensors caused by the piezoelectric effect when the knee and hip in the cloth are bent. The measured sensor outputs are transferred to a computer via Bluetooth...
March 13, 2017: Sensors
https://www.readbyqxmd.com/read/28335370/vibration-of-piezoelectric-zno-swcnt-nanowires
#2
Yao Xiao, Chengyuan Wang, Yuantian Feng
A hybrid nanowire (HNW) was constructed by coating a single-wall carbon nanotube (SWCNT) with piezoelectric zinc oxide (ZnO). The two components of the HNW interact with each other via the van der Waals (vdW) force. This paper aims to study the effect of the piezoelectricity in the ZnO layer and the inter-phase vdW interaction on the fundamental vibration of the HNWs. In doing this, a new model was developed where the two components of the HNWs were modeled as Euler beams coupled via the interphase vdW interaction...
December 15, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335239/a-flexible-360-degree-thermal-sound-source-based-on-laser-induced-graphene
#3
Lu-Qi Tao, Ying Liu, Zhen-Yi Ju, He Tian, Qian-Yi Xie, Yi Yang, Tian-Ling Ren
A flexible sound source is essential in a whole flexible system. It's hard to integrate a conventional sound source based on a piezoelectric part into a whole flexible system. Moreover, the sound pressure from the back side of a sound source is usually weaker than that from the front side. With the help of direct laser writing (DLW) technology, the fabrication of a flexible 360-degree thermal sound source becomes possible. A 650-nm low-power laser was used to reduce the graphene oxide (GO). The stripped laser induced graphene thermal sound source was then attached to the surface of a cylindrical bottle so that it could emit sound in a 360-degree direction...
June 7, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335195/pmn-pt-pvdf-nanocomposite-for-high-output-nanogenerator-applications
#4
Chuan Li, Wenbo Luo, Xingzhao Liu, Dong Xu, Kai He
The 0.7Pb(Mg1/3Nb2/3)O₃-0.3PbTiO₃(0.7PMN-0.3PT) nanorods were obtained via hydrothermal method with high yield (over 78%). Then, new piezoelectric nanocomposites based on (1-x)Pb(Mg1/3Nb2/3)O₃-xPbTiO₃ (PMN-PT) nanorods were fabricated by dispersing the 0.7PMN-0.3PT nanorods into piezoelectric poly(vinylidene fluoride) (PVDF) polymer. The mechanical behaviors of the nanocomposites were investigated. The voltage and current generation of PMN-PT/PVDF nanocomposites were also measured. The results showed that the tensile strength, yield strength, and Young's modulus of nanocomposites were enhanced as compared to that of the pure PVDF...
April 11, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28333626/temperature-dependence-of-domain-contributions-as-a-function-of-ageing-in-soft-and-hard-lead-zirconate-titanate-piezoelectric-ceramics
#5
Sayyed A Qaisar, Timothy P Comyn, Andrew J Bell
The stress and temperature dependence of three different PZT ceramics have been measured at 48 hours and 1 month after poling. The data were fitted to a modified Rayleigh law in which a negative quadratic stress term accounts for a saturation of the domain wall contributions at higher stress. The relative changes to the fitting parameters can be explained by the materials possessing differences in the concentration of orientable defect dipoles, but with similar distributions of relaxation time constants.
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28327501/accurate-determination-of-the-frequency-response-function-of-submerged-and-confined-structures-by-using-pzt-patches%C3%A2
#6
Alexandre Presas, David Valentin, Eduard Egusquiza, Carme Valero, Mònica Egusquiza, Matias Bossio
To accurately determine the dynamic response of a structure is of relevant interest in many engineering applications. Particularly, it is of paramount importance to determine the Frequency Response Function (FRF) for structures subjected to dynamic loads in order to avoid resonance and fatigue problems that can drastically reduce their useful life. One challenging case is the experimental determination of the FRF of submerged and confined structures, such as hydraulic turbines, which are greatly affected by dynamic problems as reported in many cases in the past...
March 22, 2017: Sensors
https://www.readbyqxmd.com/read/28326225/multimodal-cantilevers-with-novel-piezoelectric-layer-topology-for-sensitivity-enhancement
#7
Steven Ian Moore, Michael G Ruppert, Yuen Kuan Yong
Self-sensing techniques for atomic force microscope (AFM) cantilevers have several advantageous characteristics compared to the optical beam deflection method. The possibility of down scaling, parallelization of cantilever arrays and the absence of optical interference associated imaging artifacts have led to an increased research interest in these methods. However, for multifrequency AFM, the optimization of the transducer layout on the cantilever for higher order modes has not been addressed. To fully utilize an integrated piezoelectric transducer, this work alters the layout of the piezoelectric layer to maximize both the deflection of the cantilever and measured piezoelectric charge response for a given mode with respect to the spatial distribution of the strain...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28325908/tuning-of-large-piezoelectric-response-in-nanosheet-buffered-lead-zirconate-titanate-films-on-glass-substrates
#8
Anuj Chopra, Muharrem Bayraktar, Maarten Nijland, Johan E Ten Elshof, Fred Bijkerk, Guus Rijnders
Renewed interest has been witnessed in utilizing the piezoelectric response of PbZr0.52Ti0.48O3 (PZT) films on glass substrates for applications such as adaptive optics. Accordingly, new methodologies are being explored to grow well-oriented PZT thin films to harvest a large piezoelectric response. However, thin film piezoelectric response is significantly reduced compared to intrinsic response due to substrate induced clamping, even when films are well-oriented. Here, a novel method is presented to grow preferentially (100)-oriented PZT films on glass substrates by utilizing crystalline nanosheets as seed layers...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28323633/rotational-magneto-acousto-electric-tomography-maet-theory-and-experimental-validation
#9
L Kunyansky, C P Ingram, R S Witte
We present a novel two-dimensional (2D) MAET scanner, with a rotating object of interest and two fixed pairs of electrodes. Such an acquisition scheme, with our novel reconstruction techniques, recovers the boundaries of the regions of constant conductivity uniformly well, regardless of their orientation. We also present a general image reconstruction algorithm for the 2D MAET in a circular chamber with point-like electrodes immersed into the saline surrounding the object. An alternative linearized reconstruction procedure is developed, suitable for recovering the material interfaces (boundaries) when a non-ideal piezoelectric transducer is used for acoustic excitation...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28321656/molecular-modeling-of-the-piezoelectric-properties-of-ferroelectric-composites-containing-polyvinylidene-fluoride-pvdf-and-either-graphene-or-graphene-oxide
#10
Vladimir S Bystrov, Igor K Bdikin, Maksim Silibin, Dmitry Karpinsky, Svitlana Kopyl, Ekaterina V Paramonova, Gil Goncalves
Molecular modeling of ferroelectric composites containing polyvinylidene fluoride (PVDF) and either graphene (G) or graphene oxide (GO) were performed using the semi-empirical quantum approximation PM3 in HyperChem. The piezo properties of the composites were analyzed and compared with experimental data obtained for P(VDF-TrFE)-GO films. Qualitative agreement was obtained between the results of the modeling and the experimental results in terms of the properties of the measured effective piezoelectric coefficient d 33eff and its decrease in the presence of G/GO in comparison with the average computed piezoelectric coefficient <d 33>...
April 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28319821/application-of-p4-polyphase-codes-pulse-compression-method-to-air-coupled-ultrasonic-testing-systems
#11
Honggang Li, Zhenggan Zhou
Air-coupled ultrasonic testing systems are usually restricted by low signal-to-noise ratios (SNR). The use of pulse compression techniques based on P4 Polyphase codes can improve the ultrasound SNR. This type of codes can generate higher Peak Side Lobe (PSL) ratio and lower noise of compressed signal. This paper proposes the use of P4 Polyphase sequences to code ultrasound with a NDT system based on air-coupled piezoelectric transducer. Furthermore, the principle of selecting parameters of P4 Polyphase sequence for obtaining optimal pulse compression effect is also studied...
March 3, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28317841/rectifying-the-output-of-vibrational-piezoelectric-energy-harvester-using-quantum-dots
#12
Lijie Li
Piezoelectric energy harvester scavenges mechanical vibrations and generates electricity. Researchers have strived to optimize the electromechanical structures and to design necessary external power management circuits, aiming to deliver high power and rectified outputs ready for serving as batteries. Complex deformation of the mechanical structure results in charges with opposite polarities appearing on same surface, leading to current loss in the attached metal electrode. External power management circuits such as rectifiers comprise diodes that consume power and have undesirable forward bias...
March 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28317385/does-perceived-safety-modify-the-effectiveness-of-a-walking-group-intervention-designed-to-promote-physical-activity
#13
Jamila L Kwarteng, Amy J Schulz, Graciela B Mentz, Barbara A Israel, Trina R Shanks, Denise White Perkins
PURPOSE: To examine whether perceived safety modified the effectiveness of the Walk Your Heart to Health (WYHH) intervention in promoting physical activity and reducing central adiposity in predominantly non-Latino black (henceforth black) and Latino communities. DESIGN: Generalized estimation equations were used to assess modifying effects of perceived safety on the route and perceived neighborhood safety on (1) WYHH participation at 8 weeks and 32 weeks, (2) associations between participation and physical activity, and (3) associations between physical activity and central adiposity...
January 1, 2017: American Journal of Health Promotion: AJHP
https://www.readbyqxmd.com/read/28316942/piezosurgery-a-boon-for-modern-periodontics
#14
REVIEW
Mathai Thomas, Uttam Akula, Kranti K R Ealla, Nirosha Gajjada
Dentistry has undergone significant advancement and has seen several changing concepts over a decade. One such novel innovation is piezosurgery. Piezoelectric bone surgery or otherwise known as piezosurgery is a novel technique invented by Professor Vercellotti in 1988 to overcome the limitations of traditional instrumentation in oral bone surgery by modifying and improving conventional ultrasound technology. It is a promising, meticulous, and soft tissue sparing system for bone cutting based on low frequency ultrasonic microvibrations...
January 2017: Journal of International Society of Preventive & Community Dentistry
https://www.readbyqxmd.com/read/28302337/the-accuracy-of-computer-guided-piezocision-a-prospective-clinical-pilot-study
#15
M Cassetta, M Ivani
Computer-guided piezocision can be used to overcome the disadvantages of corticotomy in accelerating orthodontic tooth movement. The aim of this clinical pilot study was to determine the accuracy of this technique. STROBE guidelines were followed. Ten patients were selected and treated. Using new dedicated planning software, the piezocision cuts were properly positioned in virtual models. A surgical guide was designed and printed with slots to guide the scalpel blade first and then the piezoelectric micro-saw...
March 13, 2017: International Journal of Oral and Maxillofacial Surgery
https://www.readbyqxmd.com/read/28300637/integrated-mass-spectrometry-imaging-and-omics-workflows-on-the-same-tissue-section-using-grid-aided-parafilm-assisted-microdissection
#16
Jusal Quanico, Julien Franck, Maxence Wisztorski, Michel Salzet, Isabelle Fournier
BACKGROUND: In spite of the number of applications describing the use of MALDI MSI, one of its major drawbacks is the limited capability of identifying multiple compound classes directly on the same tissue section. METHODS: We demonstrate the use of grid-aided, parafilm-assisted microdissection to perform MALDI MS imaging and shotgun proteomics and metabolomics in a combined workflow and using only a single tissue section. The grid is generated by microspotting acid dye 25 using a piezoelectric microspotter, and this grid was used as a guide to locate regions of interest and as an aid during manual microdissection...
March 11, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28299698/piezoelectric-plate-sensor-peps-for-analysis-of-specific-kras-point-mutations-at-low-copy-number-in-urine-without-dna-isolation-or-amplification
#17
Ceyhun E Kirimli, Wei-Heng Shih, Wan Y Shih
We have examined in situ detection of single-nucleotide KRAS mutations in urine using a (Pb(Mg1/3Nb2/3)O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) coated with a 17-nucleotide (nt) locked nucleic acid (LNA) probe DNA complementary to the KRAS mutation without DNA isolation and amplification. In situ mutant (MT) DNA in urine in a wild type (WT) background was carried out at a flow rate of 4 mL/min and at 63 °C with the PEPS vertically situated at the center of the flow. Both the temperature and the impingement flow force discriminated the wild type...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28299696/finger-powered-electro-digital-microfluidics
#18
Cheng Peng, Y Sungtaek Ju
Portable microfluidic devices are promising for point-of-care (POC) diagnosis and bio- and environmental surveillance in resource-constrained or non-laboratory environments. Lateral-flow devices, some built off paper or strings, have been widely developed but the fixed layouts of their underlying wicking/microchannel structures limit their flexibility and present challenges in implementing multistep reactions. Digital microfluidics can circumvent these difficulties by addressing discrete droplets individually...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28299695/development-of-novel-piezoelectric-biosensor-using-pzt-ceramic-resonator-for-detection-of-cancer-markers
#19
Li Su, Chi-Chun Fong, Pik-Yuan Cheung, Mengsu Yang
A novel biosensor based on piezoelectric ceramic resonator was developed for direct detection of cancer markers in the study. For the first time, a commercially available PZT ceramic resonator with high resonance frequency was utilized as transducer for a piezoelectric biosensor. A dual ceramic resonators scheme was designed wherein two ceramic resonators were connected in parallel: one resonator was used as the sensing unit and the other as the control unit. This arrangement minimizes environmental influences including temperature fluctuation, while achieving the required frequency stability for biosensing applications...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28299694/electrochemical-quartz-crystal-nanobalance-eqcn-based-biosensor-for-sensitive-detection-of-antibiotic-residues-in-milk
#20
Sunil Bhand, Geetesh K Mishra
An electrochemical quartz crystal nanobalance (EQCN), which provides real-time analysis of dynamic surface events, is a valuable tool for analyzing biomolecular interactions. EQCN biosensors are based on mass-sensitive measurements that can detect small mass changes caused by chemical binding to small piezoelectric crystals. Among the various biosensors, the piezoelectric biosensor is considered one of the most sensitive analytical techniques, capable of detecting antigens at picogram levels. EQCN is an effective monitoring technique for regulation of the antibiotics below the maximum residual limit (MRL)...
2017: Methods in Molecular Biology
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