A Robust Method for Drilling Monitoring using Acoustic Emission

Acoustic Emission (AE) is considered an efficient tool for monitoring of machining operations, for both tool condition and working piece integrity. However, the use of AE is more challenging in case of drilling, due to heavy dependence of AE signals to process parameters. Monitoring drilling using AE thus requires robust methods to extract useful information in signals. The paper describes such a method that adapts itself to AE signals obtained during drilling, allowing the automatic set-up of an adaptive threshold to perform AE count rate. Experiments have been conducted that show the robustness of the method and its usefulness in drilling monitoring.International audienceAcoustic Emission (AE) is considered an efficient tool for monitoring of machining operations, for both tool condition and working piece integrity. However, the use of AE is more challenging in case of drilling, due to heavy dependence of AE signals to process parameters. Monitoring drilling using AE thus requires robust methods to extract useful information in signals. The paper describes such a method that adapts itself to AE signals obtained during drilling, allowing the automatic set-up of an adaptive threshold to perform AE count rate. Experiments have been conducted that show the robustness of the method and its usefulness in drilling monitoring

Métabolomique et spectrométrie de masse : de nouvelles perspectives en analyse biomédicale

Metabolomics is defined as an integrative approach consisting in the comprehensive analysis of all of the small molecules of a biological system (the "metabolome"). The main objective of metabolomics in medecine is to discover metabolic biomarkers for diseases. Mass spectrometry (MS) coupled to liquid or gas chromatography is amongst major analytical tools used in metabolomics. However, the holistic approach used in metabolomics requires very good performances of the analytical system (chromatographic column and MS equipment) and the use of non-conventional validation strategies. Metabolomics workflow can be divided in three main steps: sample preparation, MS data acquisition and processing, and statistical analysis. Processing of the "raw" data (obtained after MS acquisition) is mostly required to normalise chromatographic conditions and to carry out accurate quantification of MS features. Features resulting from this processing may be identified later. The statistical analyses include typically multivariate techniques such as supervised and non-supervised methods. Supervised methods make use of the response variable (e.g., case/control) for model construction while non-supervised methods do not use this piece of information. When the study is focused on a particular set of metabolites, targeted metabolomics could be an interesting alternative to the holistic approach since it may allow absolute quantitation and be associated with a reduced cost

Validation of 3D spino-pelvic muscle reconstructions based on dedicated MRI sequences for fat-water quantification

 Objectives: To evaluate a protocol, including MRI acquisition with dedicated sequences for fat-water quantification and semi-automatic segmentation, for 3D geometry measurement and fat infiltration of key muscles of the spino-pelvic complex. Materials and Methods: MRI Protocol: Two axial acquisitions from the thoraco-lumbar region to the patella were obtained: one T1 weighted and one based on the Dixon method, permitted to evaluate the proportion of fat inside each muscle. Muscle Reconstruction: With Muscl’X software, 3D reconstructions of 18 muscles or groups of muscles were obtained identifying their contours on a limited number of axial images (DPSO Method); 3D references were obtained only on T1 acquisitions identifying the contour of the muscles on all axial images. Evaluation: For two volunteers, three operators completed reconstructions three times across three sessions. Each reconstruction was projected on the reference to calculate the ‘point to surface’ error. Mean and maximal axial section, muscle volume, and muscle length calculated from the reconstructions were compared to reference values, and intra- and inter-operator variability for those parameters were evaluated. Results: 2xRMS ‘point to surface’ error was below 3 mm, on average. The agreement between the two methods was variable between muscles [-4.50; 8.00 %] for the mean axial section, the length and the volume. Intra- and inter-operator variability were less than 5% and comparison of variability for the Fat and T1 reconstructions did not reveal any significant differences. Discussion: Excellent inter- and intra-operator reliability was demonstrated for 3D muscular reconstruction using the DPSO method and Dixon images that allowed generation of patient-specific musculoskeletal models. Fondation Paristech, ISS

Evidence for enhanced neurobehavioral vulnerability to nicotine during periadolescence in rats

Epidemiological studies indicate that there is an increased likelihood for the development of nicotine addiction when cigarette smoking starts early during adolescence. These observations suggest that adolescence could be a “critical ” ontogenetic period, during which drugs of abuse have distinct effects responsible for the development of dependence later in life. We compared the long-term behavioral and molecular effects of repeated nicotine treatment during either periadolescence or postadolescence in rats. It was found that exposure to nicotine during periadolescence, but not a similar exposure in the postadolescent period, increased the intravenous self-administration of nicotine and the expression of distinct subunits of the ligand-gated acetylcholine receptor in adult animals. Both these changes indicated an increased sensitivity to the addictive properties of nicotine. In conclusion, adolescence seems to be a critical developmental period, characterized by enhanced neurobehavioral vulnerability to nicotine. Key words: nicotine; adolescence; intravenous; self-administration; acetylcholine receptor; PC

Frequency shifts of photoassociative spectra of ultracold metastable Helium atoms : a new measurement of the s-wave scattering length

We observe light-induced frequency shifts in one-color photoassociative spectra of magnetically trapped $^4$He$^*$ atoms in the metastable $2^3S_1$ state. A pair of ultracold spin-polarized $2^3S_1$ helium atoms is excited into a molecular bound state in the purely long range $0_u^+$ potential connected to the $2^3S_1 - 2^3P_0$ asymptote. The shift arises from the optical coupling of the molecular excited bound state with the scattering states and the bound states of two colliding $2^3S_1$ atoms. We measure the frequency-shifts for several ro-vibrational levels in the $0^+_u$ potential and find a linear dependence on the photoassociation laser intensity. Comparison with a theoretical analysis provides a good indication for the s-wave scattering length $a$ of the quintet ($^5\Sigma_g^+$) potential, $a=7.2\pm 0.6$ nm, which is significantly lower than most previous results obtained by non-spectroscopic methods.Comment: 7 pages, 4 figure

Conformal Printing of Graphene for Single- and Multilayered Devices onto Arbitrarily Shaped 3D Surfaces

Printing has drawn a lot of attention as a means of low per-unit cost and high throughput patterning of graphene inks for scaled-up thin-form factor device manufacturing. However, traditional printing processes require a flat surface and are incapable of achieving patterning on to 3D objects. Here, we present a conformal printing method to achieve functional graphene-based patterns on to arbitrarily-shaped surfaces. Using experimental design, we formulate a water-insoluble graphene ink with optimum conductivity. We then print single and multi-layered electrically functional structures on to a sacrificial layer using conventional screen printing. The print is then floated on water, allowing the dissolution of the sacrificial layer, while retaining the functional patterns. The single and multilayer patterns can then be directly transferred on to arbitrarily-shaped 3D objects without requiring any post deposition processing. Using this technique, we demonstrate conformal printing of single and multilayer functional devices that include joule heaters, resistive deformation sensors and proximity sensors on hard, flexible and soft substrates, such as glass, latex, thermoplastics, textiles, and even candies and marshmallows. Our simple strategy offers great promises to add new device and sensing functionalities to previously inert 3D surfaces.EPSRC (EP/L016087/1) Graphene Flagshi

Conformal Printing of Graphene for Single- and Multilayered Devices onto Arbitrarily Shaped 3D Surfaces

Printing has drawn a lot of attention as a means of low per-unit cost and high throughput patterning of graphene inks for scaled-up thin-form factor device manufacturing. However, traditional printing processes require a flat surface and are incapable of achieving patterning on to 3D objects. Here, we present a conformal printing method to achieve functional graphene-based patterns on to arbitrarily-shaped surfaces. Using experimental design, we formulate a water-insoluble graphene ink with optimum conductivity. We then print single and multi-layered electrically functional structures on to a sacrificial layer using conventional screen printing. The print is then floated on water, allowing the dissolution of the sacrificial layer, while retaining the functional patterns. The single and multilayer patterns can then be directly transferred on to arbitrarily-shaped 3D objects without requiring any post deposition processing. Using this technique, we demonstrate conformal printing of single and multilayer functional devices that include joule heaters, resistive strain sensors and proximity sensors on hard, flexible and soft substrates, such as glass, latex, thermoplastics, textiles, and even candies and marshmallows. Our simple strategy offers great promises to add new device and sensing functionalities to previously inert 3D surfaces.EPSRC (EP/L016087/1) Graphene Flagshi