Compact fibre Bragg grating-based thermometer for on-line temperature monitoring of drill bits

In this communication, a novel compact fibre Bragg grating-based thermometer for on-line temperature monitoring of drill bits is reported. Our proposed technique can potentially be used to optimize any drilling process, requiring the use of small drill bits, through direct temperature measurement at the drill bit instead of relying on indirect parameters (speed of rotation, applied force) in order to avoid an overheating as it is currently done nowadays

Modelling human choices: MADeM and decision‑making

Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

Contrôle qualité et numérisation tridimensionnelle de pièces horlogères par tomographie rayons X

La tomographie par rayons X est une technique bien connue dans le domaine médical, elle est cependant moins répandue dans le secteur industriel. Cette méthode d'imagerie très performante permet des mesures tridimensionnelles pour des pièces de géométrie complexe. Elle est en passe de devenir une méthode de mesure incontournable pour le contrôle qualité

Low-cost nanostructured thin films as covert laser readable security tags for large-scale productions tracking

We report here the feasibility study of anti-counterfeiting low-cost nanostructured flexible security tags for the tracking of large-scale fabrication products, such as pharmaceuticals or original equipment manufacturers. The fabrication process makes use of the mature nanotechnology called Template Synthesis to shape thin track-etched polymer film into covert laser readable tags, combining random self-organized structures with organized patterns. Techniques are developed to drastically limit the number of fabrication steps and keep fabrication costs low, while opening to numerous adjustment parameters. A dedicated, simple optical setup is presented, to capture speckle images of such tags lightened up by light emitting diodes or laser beams. Speckle images are analyzed in terms of encoding parameters, found here quite numerous to ensure a large coding range of large-scale production batches. We particularly highlight ultra-dark areas in speckle images, where nanowire structures completely inhibit speckle patterns. This unique, high-contrast optical feature addresses these low-cost nanostructured thin films to provide a very promising solution for large-scale security tags

Liquid-air based Fabry-Pérot cavity on fiber tip sensor

This paper presents a Fabry-Perot fiber tip sensor based on an air-liquid filled cavity. The cavity is sealed off by a thin gold coated membrane of parylene C, between 300 and 350 nm, creating a particularly flexible diaphragm. In order to retrieve and track the cavity of interest from other cavities formed within the sensor tip, a signal processing of the feedback signal is performed by inverse fast Fourier transform. The experimental sensor has been manufactured and tested for temperature, giving cavity length sensitivities of 6.1 nm/°C and 9.6 nm/°C for temperature increase and decrease respectively. The external gas pressure response gives a sensitivity of 15 nm/kPa. The fiber sensor has also been adapted for force sensing after silicone embedment and has shown a sensitivity of about 8.7 nm/mN. Finally, the sensor has been tested on insertion into a human temporal bone, proving that it could be an interesting candidate for insertion force monitoring for robotic cochlear implantation

Fiber Bragg grating-based thermometer for drill bit temperature monitoring

The temperature measurement of a drill bit during an implantology drilling process is proposed by using a fiber Bragg grating fitted inside the drill bit. Due to the rotational nature of the drilling process, a free-space fiber-optic rotary joint is used for interrogating the fiber Bragg grating. Due to mechanical clearances and interferometric noise induced at this rotary joint, signal integrity is strongly deteriorated and is not workable without adequate measures. These measures involve a proper fiber lensing and a signal processing in order to remove the interferometric noise. Finally, a heating measurement on an implantology drill bit is performed and discussed for drilling several holes on a pork jaw sample

Liquid-air based Fabry-Pérot cavity on fiber tip sensor

This paper presents a Fabry-Perot fiber tip sensor based on an air-liquid filled cavity. The cavity is sealed off by a thin gold coated membrane of parylene C, between 300 and 350 nm, creating a particularly flexible diaphragm. In order to retrieve and track the cavity of interest from other cavities formed within the sensor tip, a signal processing of the feedback signal is performed by inverse fast Fourier transform. The experimental sensor has been manufactured and tested for temperature, giving cavity length sensitivities of 6.1 nm/°C and 9.6 nm/°C for temperature increase and decrease respectively. The external gas pressure response gives a sensitivity of 15 nm/kPa. The fiber sensor has also been adapted for force sensing after silicone embedment and has shown a sensitivity of about 8.7 nm/mN. Finally, the sensor has been tested on insertion into a human temporal bone, proving that it could be an interesting candidate for insertion force monitoring for robotic cochlear implantation