Development of an instrumentation system embedded on FPGA for real time measurement of mechanical vibrations in rotating machinery

The real-time monitoring of events in an industrial plant is vital, to monitor the actual conditions of operation of the machinery responsible for the manufacturing process. A predictive maintenance program includes condition monitoring of the rotating machinery, to anticipate possible conditions of failure. To increase the operational reliability it is thus necessary an efficient tool to analyze and monitor the equipments, in real-time, and enabling the detection of e.g. incipient faults in bearings. To fulfill these requirements some innovations have become frequent, namely the inclusion of vibration sensors or stator current sensors. These innovations enable the development of new design methodologies that take into account the ease of future modifications, upgrades, and replacement of the monitored machine, as well as expansion of the monitoring system. This paper presents the development, implementation and testing of an instrument for vibration monitoring, as a possible solution to embed in industrial environment. The digital control system is based on an FPGA, and its configuration with an open hardware design tool is described. Special focus is given to the area of fault detection in rolling bearings. © 2012 IEEE.

Intense visible photoluminescence in Ba(Zr0.25Ti0.75)O-3 thin films

Photoluminescence at room temperature in Ba(Zr0.25Ti0.75)O-3 thin films was explained by the degree of structural order-disorder. Ultraviolet-visible absorption spectroscopy, photoluminescence, and first principles quantum mechanical measurements were performed. The film annealed at 400 degrees C for 4 h presents intense visible photoluminescence behavior at room temperature. The increase of temperature and annealing time creates [ZrO6]-[TiO6] clusters in the lattice leading to the trapping of electrons and holes. Thus, [ZrO5]-[TiO6]/[ZrO6]-[TiO6] clusters were the main reason for the photoluminescence behavior.

Estudo das propriedades físicas de blendas de PVDF/Látex visando aplicação como biomaterial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Harmonical oscillator and electro-mechanical analogy: an interdiscinary experiment to high precision mass variation measurements

De forma geral, os cursos de física clássica oferecidos nas universidades carecem de exemplos de aplicações nas áreas de química e biologia, o que por vezes desmotivam os alunos de graduação destas áreas a estudarem os conceitos físicos desenvolvidos em sala de aula. Neste texto, a analogia entre os osciladores elétrico e mecânico é explorada visando possívies aplicações em química e biologia, mostrando-se de grande valia devido ao seu uso em técnicas de medição de variação de massa com alta precisão, tanto de forma direta como indireta. Estas técnicas são conhecidas como técnicas eletrogravimétricas e são de especial importância em aplicações que envolvem biossensores. Desta forma, o texto explora o estudo da analogia eletromecânica de forma interdisciplinar envolvendo as áreas de física, química e biologia. Baseado nessa analogia é proposto um experimento que permite a sua aplicação em diferentes níveis conceituais dessas disciplinas, tanto em abordagem básica como mais profunda.

Influence of Heat Treatment and Oxygen Doping on the Mechanical Properties and Biocompatibility of Titanium-Niobium Binary Alloys

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the Substitutional Solute on the Mechanical Properties of Ti-Nb Binary Alloys for Biomedical Use

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of the oxygen and nitrogen interstitial diffusion coeficient in niobium by mechanical spectroscopy

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

Nitrogen diffusion in the Nb-1.0wt%Zr measured by mechanical spectroscopy

The scientific and technological development in the area of new materials contributed to several applications of niobium and its alloys in nuclear power plants as well as in aerospace, aeronautics, automobile and naval industries. This paper presents the interstitial diffusion coefficients of nitrogen in solid solution in the Nb-1.0wt%Zr alloy using internal friction measurements obtained by mechanical spectroscopy, which uses a torsion pendulum operating at an oscillation frequency between 1.0 Hz and 10.0 Hz. The temperature range varies from 300K to 700K, at a heating rate of 1 K/min and vacuum better than 2 x 10(-6) Torr. The results showed an increase of the interstitial diffusion coefficient of nitrogen that was correlated with configurational considerations for the octahedral interstitials.

Oxygen diffusion in Ti-10Mo alloys measured by mechanical spectroscopy

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

Oxygen Diffusion in an Nb-Ta Alloy Measured by Mechanical Spectroscopy

When metals that present bcc crystalline structure receive the addition of interstitial atoms as oxygen, nitrogen, hydrogen and carbon, they undergo significant changes in their physical properties because they are able to dissolve great amounts of those interstitial elements, and thus form solid solutions. Niobium and most of its alloys possess a bcc crystalline structure and, because Brazil is the largest world exporter of this metal, it is fundamental to understand the interaction mechanisms between interstitial elements and niobium or its alloys. In this study, mechanical spectroscopy (internal friction) measurements were performed on Nb-8.9wt%Ta alloys containing oxygen in solid solution. The experimental results presented complex internal friction spectra. With the addition of substitutional solute, interactions between the two types of solutes (substitutional and interstitial) were observed, considering that the random distribution of the interstitial atoms was affected by the presence of substitutional atoms. Interstitial diffusion coefficients, pre-exponential factors and activation energies were calculated for oxygen in this alloy.

Oxygen Diffusion in Ti-20Mo Alloys, used as Biomaterial, Measured by Mechanical Spectroscopy

Titanium alloys are favorable implant materials for orthopedic applications, due to their desirable properties such as good corrosion resistance, low elasticity modulus, and excellent biocornpatibility. The research on titanium alloys is concentrated in the beta type, as the Ti-20Mo alloys and the addition of interstitial elements in these metals cause changes in their mechanical properties. The mechanical spectroscopy measurements have been frequently used in order to verify the behavior of these interstitials atoms in metallic alloys. This paper presents the study of oxygen diffusion in Ti-20Mo alloys using mechanical spectroscopy measurements. A thermally activated relaxation structure was observed in the sample after oxygen doping. It was associated with the interstitial diffusion of oxygen atoms in a solid solution in the alloy. The diffusion coefficient for the oxygen diffusion in the alloy was obtained by the frequency dependence of the peak temperature and by using a simple mathematical treatment of the relaxation structure and the Arrhenius law.

Anelastic Relaxation Measurements in Nb-46wt%Ti Alloys with Interstitial Solutes in Solid Solution

Anelastic relaxation measurements were performed in a Nb-46wt%Ti alloy, in the temperature range of 300 to 700 K, using a torsion pendulum operating at an oscillating frequency near 2.0 Hz. The samples were measured in different conditions: cold worked, annealed in ultra-high vacuum and doped with several quantities of nitrogen. The relaxation spectra obtained were resolved into their component peaks, corresponding to the different kinds of interaction of the interstitial solutes with the metallic matrix. The relaxation parameters of each process were calculated using Debye's elementary peaks.

Nitrogen diffusion in the Nb-2.0wt%Ti measured by mechanical spectroscopy

Metals that present bcc crystalline structure, when receiving addition of interstitial atoms as oxygen, nitrogen, hydrogen and carbon, undergo significant changes in their physical properties, being able to dissolve great amounts of those interstitial elements, thus forming solid solutions. Niobium and most of its alloys possess bcc crystalline structure and, as Brazil is the largest world exporter of this metal, it is fundamental to understand the interaction mechanisms between interstitial elements and niobium or its alloys. In this paper, mechanical spectroscopy (internal friction) measurements were performed in Nb-2.0wt%Ti alloys containing nitrogen in solid solution. The experimental results presented complex internal friction spectra and with the addition of substitutional solute, it was observed interactions between the two types of solutes (substitutional and interstitial), considering that the random distribution of the interstitial atoms was affected by the presence of substitutional atoms. Interstitial diffusion coefficients, pre-exponential factors and activation energies were calculated for nitrogen in the Nb-2.0wt%Ti alloys.

Metal-insulator transition in Nd1-x Eu-x NiO3 probed by specific heat and anelastic measurements

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

Effects of buprenorphine, carprofen and saline on thermal and mechanical nociceptive thresholds in cats

To evaluate a prototype pressure stimulus device for use in the cat and to compare with a known thermal threshold device.Eight healthy adult cats weighing between 3.0 and 4.9 kg.Pressure stimulation was given via a plastic bracelet taped around the forearm. Three 2.4 mm diameter ball bearings, in a 10-mm triangle, were advanced against the craniolateral surface of the antebrachium by manual inflation of a modified blood pressure bladder. Pressure in the cuff was recorded at the end point (leg shake and head turn). Thermal threshold was also tested. Stimuli were stopped if they reached 55 degrees C or 450 mmHg without response. After four pressure and thermal threshold baselines, each cat received SC buprenorphine 0.01 mg kg(-1), carprofen 4 mg kg(-1) or saline 0.3 mL in a three period cross-over study with a 1-week interval. The investigator was blinded to the treatment. Measurements were made at 0.25. 0.5, 0.75, 1, 2, 3, 4, 6, 8, and 24 hours after injection. Data were analyzed by using ANOVA.There were no significant changes in thermal or pressure threshold after administration of saline or carprofen, but thermal threshold increased from 60 minutes until 8 hours after administration of buprenorphine (p < 0.05). The maximum increase in threshold from baseline (Delta T-max) was 3.5 +/- 3.1 degrees C at 2 hours. Pressure threshold increased 2 hours after administration of buprenorphine (p < 0.05) when the increase in threshold above baseline (Delta P-max) was 162 +/- 189 mmHg.This pressure device resulted in thresholds that were affected by analgesic treatment in a similar manner but to a lesser degree than the thermal method. Pressure stimulation may be a useful additional method for analgesic studies in cats.