Piezo-assisted nuclear transfer affects cloning efficiency and may cause apoptosis

Even though it generates healthy adults, nuclear transfer in mammals remains an inefficient process. Mainly attributed to abnormal reprograming of the donor chromatin, this inefficiency may also be caused at least partly by a specific effect of the clonin

Imaging domains in BaTiO3 single crystal nanostructures: comparing information from transmission electron microscopy and piezo-force microscopy

This article compares and contrasts information
obtained, using transmission electron microscopy (TEM)
and piezo-force microscopy (PFM), on domain configurations
adopted in single crystal lamellae of BaTiO3, that had
been cut directly from bulk using a focused ion beam
microscope with top and bottom surfaces parallel to
{100}pseudocubic. Both forms of imaging reveal domain
walls parallel to {110}pseudocubic, consistent with sets of 90
domains with dipoles oriented parallel to the two
\001[pseudocubic directions in the plane of the lamellae.
However, the domain width was observed to be dramatically
larger using PFM than it was using TEM. This suggests
significant differences in the surface energy densities
that drive the domain formation in the first place, that could
relate to differences in the boundary conditions in the two
modes of imaging (TEM samples are imaged under high
vacuum, whereas PFM imaging was performed in air).
Attempts were made to map local dipole orientations
directly, using a form of ‘vector’ PFM. However, information
inferred was largely inconsistent with the known
crystallography of the samples, raising concern about the
levels of care needed for accurate interpretation of PFM
images.

A crack on the interface of piezo-electric bodies

Singularities of elastic and electric fields are investigated at the tip of a crack on the interface of two anisotropic piezo-electric media under various boundary conditions on the crack surfaces. The Griffith formulae are obtained for increments of energy functionals due to growth of the crack and the notion of the energy release matrix is introduced. Normalization conditions for bases of singular solution are proposed to adapt them to the energy, stress, and deformation fracture criteria. Connections between these bases are determined and additional properties of the deformation basis related to the notion of electric surface enthalpy are established.

Chemical gas sensors based on functionalized self-actuated piezo-resistive cantilevers

Der Schwerpunkt dieser Arbeit liegt in der Anwendung funktionalisierter Mikrocantilever mit integrierter bimorpher Aktuation und piezo-resistiver Detektion als chemische Gassensoren für den schnellen, tragbaren und preisgünstigen Nachweis verschiedener flüchtiger Substanzen. Besondere Beachtung erfährt die Verbesserung der Cantilever-Arbeitsleistung durch den Betrieb in speziellen Modi. Weiterer Schwerpunkt liegt in der Untersuchung von spezifischen Sorptionswechselwirkungen und Anwendung von innovativen Funktionsschichten, die bedeutend auf die Sensorselektivität wirken.

Analysis and manipulation of the structure of odor plumes from a piezo-electric release system and measurements of upwind flight of male Almond Moths, Cadra cautella, to pheromone plumes

We investigated the plume structure of a piezo-electric sprayer system, set up to release ethanol in a wind tunnel, using a fast response mini-photoionizaton detector. We recorded the plume structure of four different piezo-sprayer configurations: the sprayer alone; with a 1.6-mm steel mesh shield; with a 3.2-mm steel mesh shield; and with a 5 cm circular upwind baffle. We measured a 12 × 12-mm core at the center of the plume, and both a horizontal and vertical cross-section of the plume, all at 100-, 200-, and 400-mm downwind of the odor source. Significant differences in plume structure were found among all configurations in terms of conditional relative mean concentration, intermittency, ratio of peak concentration to conditional mean concentration, and cross-sectional area of the plume. We then measured the flight responses of the almond moth, Cadra cautella, to odor plumes generated with the sprayer alone, and with the upwind baffle piezo-sprayer configuration, releasing a 13:1 ratio of (9Z,12E)-tetradecadienyl acetate and (Z)-9-tetradecenyl acetate diluted in ethanol at release rates of 1, 10, 100, and 1,000 pg/min. For each configuration, differences in pheromone release rate resulted in significant differences in the proportions of moths performing oriented flight and landing behaviors. Additionally, there were apparent differences in the moths’ behaviors between the two sprayer configurations, although this requires confirmation with further experiments. This study provides evidence that both pheromone concentration and plume structure affect moth orientation behavior and demonstrates that care is needed when setting up experiments that use a piezo-electric release system to ensure the optimal conditions for behavioral observations.

Piezo and Dielectric Properties of PHB-PZT Composite

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of a Piezo Drill for Intracytoplasmic Sperm Injection into Cattle Oocytes Activated with Ionomycin Associated with Roscovitine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Piezo and pyroelectric radiation dosimetry

The authors review the use of photoacoustic and pyroelectric radiation dosimeters. They compare the characteristics and results obtained with a photoacoustic radiation dosimeter (PARD) and a pyroelectric radiation dosimeter (PERD). The PARD and the PERD can be used to measure the energy fluence rate of continuous X-ray beams. In the same way, the single-pulse photoacoustic radiation dosimeter and the single-pulse pyroelectric radiation dosimeter (PPERD) were compared. They can measure the energy fluence of a single pulse of X-radiation. A theoretical model to explain the results obtained with the PPERD is presented and compared with experimental results.

Otimização do processamento para obtenção de compósitos polímero/cerâmica com propriedades piezo e piroelétricas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Propriedades piezo, piroelétrica e dielétrica de compósitos cerâmica ferroelétrica/polímero dopados com polianilina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Piezo force microscopy and peakforce tuna measurements of III-V semiconductor nanowires

GaN, InP and GaAs nanowires were investigated for piezoelectric response. Nanowires and structures based on them can find wide applications in areas purposes such as nanogenarators, nanodrives, Solar cells and other perspective areas. Experemental measurements were carried out on AFM Bruker multimode 8 and data was handled with Nanoscope software. AFM techniques permitted not only to visualize the surface topography, but also to show distribution of piezoresponse and allowed to calculate its properties. The calculated values are in the same range as published by other authors.

Structural health monitoring of bridges using acoustic emission technology

Bridges are an important part of society's infrastructure and reliable methods are necessary to monitor them and ensure their safety and efficiency. Bridges deteriorate with age and early detection of damage helps in prolonging the lives and prevent catastrophic failures. Most bridges still in used today were built decades ago and are now subjected to changes in load patterns, which can cause localized distress and if not corrected can result in bridge failure. In the past, monitoring of structures was usually done by means of visual inspection and tapping of the structures using a small hammer. Recent advancements of sensors and information technologies have resulted in new ways of monitoring the performance of structures. This paper briefly describes the current technologies used in bridge structures condition monitoring with its prime focus in the application of acoustic emission (AE) technology in the monitoring of bridge structures and its challenges.