In situ multi‐axial loading frame to probe elastomers using X‐ray scattering

International audienceAn in situ tensile-shear loading device has been designed to study elastomer crystallization using synchrotron X‐ray scattering at the Synchrotron Soleil on the DiffAbs beamline. Elastomer tape specimens of thickness 2 mm can be elongated by up to 500% in the longitudinal direction and sheared by up to 200% in the transverse direction. The device is fully automated and plugged into the TANGO control system of the beamline allowing synchronization between acquisition and loading sequences. Experimental results revealing the evolution of crystallization peaks under load are presented for several tension/shear loading sequences

How to assess the role of Pt and Zn in the nephrotoxicity of Pt anti-cancer drugs?: An investigation combining μXRF and statistical analysis. Part II: Clinical application

International audienceIn this contribution, an approach developed previously for mice is used for human biopsy. In the case of patient 1, Pt detection is performed 6 days after the last oxaliplatin infusion, while for patient 2, the biopsy was performed more than 15 days after his first platin infusion and several dialysis. Even for these biological samples, experiments show that synchrotron mediated mXRF is a suitable tool to detect Pt in kidney biopsy, and thus probably for any organ exposed to Pt. Therefore, mXRF could also be of major interest to decipher the mechanism beyond Pt induced neurotoxicity, ototoxicity on human biopsy. Pharmacoavailability of chemotherapies is a major concern because some treatment failures are explained by poor tumor penetration of the active molecule. mXRF could be an elegant way to map the distribution of Pt inside cancerous cells at the micrometer scale. Pt and Zn are only two of the numerous trace elements that mXRF can detect; heavy metal intoxication diagnosis and the toxicity mechanism probably could also benefit from this innovative technique

Deformation modes of nanostructured thin film under controlled biaxial deformation

International audienceThis paper reports on the mechanical behaviour of nanostructured W/Cu thin films deposited on Kapton® under controlled biaxial loadings thanks to a biaxial testing device developed on DiffAbs beamline at SOLEIL synchrotron (Saint-Aubin, France). In situ tensile tests were carried out combining 2D synchrotron x-ray diffraction (XRD) and digital-image correlation (DIC) techniques. First, the elastic behaviour of the composite metallic film-polymeric substrate was investigated under equi-biaxial and non-equi-biaxial loading conditions. The results show that the strain measurements (in the crystalline film by XRD and the substrate by DIC) match to within 10^-4. This result demonstrates the full transmission of strains in the elastic domain through the film-substrate interface and thus a good adhesion of the thin film to the substrate. The second part of the paper deals with higher strains response under equi-biaxial tensile tests. The elastic limit of the nanostructured W/Cu thin films was determined at the bifurcation point between strains obtained by XRD and DIC. Deformation mechanisms such as strain localisation and film fragmentation are proposed

Estimation of stress in specimens loaded with ultrasonic fatigue machines

Piezo-electric ultrasonic fatigue machines are used to carry out fatigue tests more rapidly than what is possible using other technologies, at a frequency of . The very high cycle fatigue (VHCF) domain can be studied with these machines as cycles are reached within 14 h when specimens are loaded at stress amplitudes below the yield stress or conventional fatigue strength. The estimation of stress in specimens fatigued at high frequency is a current challenge when adopting this technology. This paper discusses the accuracy and reliability of three methods used to estimate stress amplitudes in specimens subjected to VHCF tests at a high loading frequency. Two historically used methods using strain gauges and a laser vibrometer are discussed and compared with a third, recently developed method based on time-resolved in situ X-ray diffraction (XRD). The three methods are applied to estimate the stress amplitude in a pearlitic steel specimen. The experimental artifacts and uncertainties are evaluated quantitatively to compare the benefits and limits of the methods. The experimental results show that the three methods correctly estimate the stress amplitudes applied to fatigued specimens

Microsecond time-resolved x-ray diffraction for the investigation of fatigue behavior during ultrasonic fatigue loading

International audienceA new method based on time-resolved X-ray diffraction is proposed in order to measure the elastic strain and stress during ultrasonic fatigue loading experiments. Pure Cu was chosen as an example material for the experiments using a 20 kHz ultrasonic fatigue machine mounted on the six-circle diffractometer available at the DiffAbs beamline on the SOLEIL synchrotron facility in France. A two-dimensional hybrid pixel X-ray detector (XPAD3.2) was triggered by the strain gage signal in a synchronous data acquisition scheme (pump-probe-like). The method enables studying loading cycles with a period of 50 µs, achieving a temporal resolution of 1 µs. This allows a precise reconstruction of the diffraction patterns during the loading cycles. From the diffraction patterns, the position of the peaks, their shifts and their respective broadening can be deduced. The diffraction peak shift allows the elastic lattice strain to be estimated with a resolution of ∼10 -5. Stress is calculated by the self-consistent scale-transition model through which the elastic response of the material is estimated. The amplitudes of the cyclic stresses range from 40 to 120 MPa and vary linearly with respect to the displacement applied by the ultrasonic machine. Moreover, the experimental results highlight an increase of the diffraction peak broadening with the number of applied cycles

Coherence and wavefront characterization of Si-111 monochromators using double-grating interferometry

A study of the coherence and wavefront properties of a pseudo-channel-cut monochromator in comparison with a double-crystal monochromator is presented. Using a double-grating interferometer designed for the hard X-ray regime, the complex coherence factor was measured and the wavefront distortions at the sample position were analyzed. A transverse coherence length was found in the vertical direction that was a factor of two larger for the channel-cut monochromator owing to its higher mechanical stability. The wavefront distortions after different optical elements in the beam, such as monochromators and mirrors, were also quantified. This work is particularly relevant for coherent diffraction imaging experiments with synchrotron sources. (C) 2010 International Union of Crystallography Printed in Singapore - all rights reserve

Probing the elastic properties of individual nanostructures by combining in situ atomic force microscopy and micro-x-ray diffraction

International audienceAtomic force microscopy AFM and micro-x-ray diffraction are combined to investigate nanostructures during in situ indentation. This technique allows the determination of elastic properties of individual nanoscale objects, particularly here SiGe/ Si001 self-assembled islands. Using this novel technique it was possible to select a specific island, align it in the microfocused beam, and apply a pressure onto it, using the AFM tip. Simultaneously, the x-ray diffuse scattering map from the island and the surrounding substrate was recorded in order to probe the lattice parameter change during indentation. An elastic reduction of the island lattice parameter of up to 0.6% was achieved

How to assess the role of Pt and Zn in the nephrotoxicity of Pt anti-cancer drugs?: An investigation combining mXRF and statistical analysis. Part II: Clinical application

International audienceIn this contribution, an approach developed previously for mice is used for human biopsy. In the case of patient 1, Pt detection is performed 6 days after the last oxaliplatin infusion, while for patient 2, the biopsy was performed more than 15 days after his first platin infusion and several dialysis. Even for these biological samples, experiments show that synchrotron mediated mXRF is a suitable tool to detect Pt in kidney biopsy, and thus probably for any organ exposed to Pt. Therefore, mXRF could also be of major interest to decipher the mechanism beyond Pt induced neurotoxicity, ototoxicity on human biopsy. Pharmacoavailability of chemotherapies is a major concern because some treatment failures are explained by poor tumor penetration of the active molecule. mXRF could be an elegant way to map the distribution of Pt inside cancerous cells at the micrometer scale. Pt and Zn are only two of the numerous trace elements that mXRF can detect; heavy metal intoxication diagnosis and the toxicity mechanism probably could also benefit from this innovative technique