A simple interferometric method to measure the calibration factor and displacement amplification in piezoelectric flextensional actuators

A interferometria laser constitui uma técnica consagrada para caracterizar atuadores piezoelétricos. Neste trabalho, utilizase um interferômetro de Michelson de baixo custo para mensurar o fator de calibração e a amplificação de deslocamento de um novo atuador piezoelétrico flextensional (APF), projetado através da técnica de otimização topológica. Um método simples, baseado na excitação do APF com sinal triangulare com baixa profundidade de modulação de fase óptica, permite realizara calibração absolutado interferômetro. Deslocamentos do APF para várias tensões de excitação são mensurados e a amplificação do deslocamento da piezocerâmica é determinada. A linearidade e a resposta em frequência do APF, até a frequência de 20 kHz, são avaliadasLaser interferometry is a well-established technique for the characterization of piezoelectric actuators. In this work, by using a low cost Michelson interferometer, the measurement of the calibration factor and the displacement amplification of a novel piezoelectric flextensional actuator (PFA), designed by using the topology optimization method, is performed. A simple method, based on small phase modulation depth when the PFA is driven by a triangular waveform, allows the absolute interferometer calibration. The free-displacement of the PFA for various drive voltages is measured and the displacement amplification is determined. The linearity and frequencyresponse of the PFA are evaluated up to 20 kHzFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Unesp Departamento de Engenharia ElétricaInstituto de Pesquisas Tecnológicas Centro de Metrologiade FluidosEPUSP Departamento de Mecatrônica e de Sistemas MecânicosUnesp Departamento de Engenharia Elétric

APMP supplementary comparison (APMP.L-S8) measurement of flatness of optical flat by interferometry

A reginal supplementary comparison, APMP.L-S8, was started in 2015 to demonstrate the equivalence of routine calibration services offered by NMIs to clients. Participants in this APMP.L-S8 comparison agreed to apply interferometric method for flatness measurement of the optical flats. There are two configurations of flatness interferometer used in this comparison, vertical type and horizontal type. There are seven laboratories from NMIs participated this supplementary comparison which included NIMT, NMIJ, NIM, NMC/A*STAR, MSL, NPLI and NMISA. This report describes the measurement results of two optical flats, diameter of 70 mm and 160 mm. The calibrations of this comparison were carried out by participants during the period from July 2015 to September 2016. The results show that there is a degree of equivalence below 1 for all measurands. Hence, there is a close agreement between the measurements from all participants. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).</jats:p

The Pthaladyns : GTP competitive inhibitors of dynamin I and II GTPase derived from virtual screening

We report the development of a homology model for the GTP binding domain of human dynamin I based on the corresponding crystal structure of Dictyostelium discoidum dynamin A. Virtual screening identified 2-[(2-biphenyl-2-yl-1,3-dioxo-2,3-dihydro-1H-isoindole-5-carbonyl)amino]-4-chlorobenzoic acid (1) as a approximately 170 microM potent inhibitor. Homology modeling- and focused library-led synthesis resulted in development of a series of active compounds (the "pthaladyns") with 4-chloro-2-(2-(4-(hydroxymethyl)phenyl)-1,3-dioxoisoindoline-5-carboxamido)benzoic acid (29), a 4.58 +/- 0.06 microM dynamin I GTPase inhibitor. Pthaladyn-29 displays borderline selectivity for dynamin I relative to dynamin II ( approximately 5-10 fold). Only pthaladyn-23 (dynamin I IC(50) 17.4 +/- 5.8 microM) was an effective inhibitor of dynamin I mediated synaptic vesicle endocytosis in brain synaptosomes with an IC(50) of 12.9 +/- 5.9 microM. This compound was also competitive with respect to Mg(2+).GTP. Thus the pthaladyns are the first GTP competitive inhibitors of dynamin I and II GTPase and may be effective new tools for the study of neuronal endocytosis.Luke R. Odell, Dian Howan, Christopher P. Gordon, Mark J. Robertson, Ngoc Chau, Anna Mariana, Ainslie E. Whiting, Ruben Abagyan, James A. Daniel, Nick N. Gorgani, Phillip J. Robinson and Adam McCluske