Chapitre 3 • Acoustic logging

Approaches that are typically applied in deep exploration geophysics, combining different seismic and logging methods, can be technically adapted for certain geotechnical or hydrogeological surveys or some site characterizations in the framework of seismic hazard studies. Currently it is entirely feasible to implement this type of geophysical surveying if the situation requires. After reviewing the current state of knowledge regarding borehole measurements of subsurface shear velocities applied to the geotechnical field, this book illustrates the feasibility of carrying out vertical seismic profiles (VSPs) and logs in this field. This approach also illustrates the value of combining velocity measurements of formations provided by borehole seismic tools (VSP) and acoustic (sonic) tools. An innovative example of the application of borehole seismic and logging methods is then presented in the case study of a relatively near-surface (from 20 to 130 m) karst carbonate aquifer. It shows how a multi-scale description of the reservoir can be carried out by integrating the information provided by different 3D-THR surface seismic methods, full waveform acoustic logging, VSP with hydrophones, borehole optical televiewer and flow measurements. In this book the authors provide readers with guidelines to carry out these operations, in terms of acquisitions as well as processing and interpretation. Thus, users will be able to draw inspiration to continue transferring petroleum techniques and other innovative methods for use in near-surface studies

Chapitre 2 • Well seismic surveying

Approaches that are typically applied in deep exploration geophysics, combining different seismic and logging methods, can be technically adapted for certain geotechnical or hydrogeological surveys or some site characterizations in the framework of seismic hazard studies. Currently it is entirely feasible to implement this type of geophysical surveying if the situation requires. After reviewing the current state of knowledge regarding borehole measurements of subsurface shear velocities applied to the geotechnical field, this book illustrates the feasibility of carrying out vertical seismic profiles (VSPs) and logs in this field. This approach also illustrates the value of combining velocity measurements of formations provided by borehole seismic tools (VSP) and acoustic (sonic) tools. An innovative example of the application of borehole seismic and logging methods is then presented in the case study of a relatively near-surface (from 20 to 130 m) karst carbonate aquifer. It shows how a multi-scale description of the reservoir can be carried out by integrating the information provided by different 3D-THR surface seismic methods, full waveform acoustic logging, VSP with hydrophones, borehole optical televiewer and flow measurements. In this book the authors provide readers with guidelines to carry out these operations, in terms of acquisitions as well as processing and interpretation. Thus, users will be able to draw inspiration to continue transferring petroleum techniques and other innovative methods for use in near-surface studies

Hydrodynamics and Local Turbulent Mixing of Submerged, Parallel Liquid Jets: Experiments and CFD Simulations

The hydrodynamics and local turbulent mixing of parallel multiple liquid jets, submerged in liquid, were investigated by means of experiments and computational fluid dynamics (CFD). A renormalization group (RNG) k-ε turbulence model was used to simulate the flow field. The model was validated experimentally by particle image velocimetry (PIV) measurements. In the converging region adjacent to the nozzle exits, the recirculation region disappears, and there is only ambient fluid entrainment. Different jet arrays were compared to evaluate the effects of the jet spatial arrangement on the hydrodynamics and mixing performance. A shorter mixing length in the merging region suggests that mixing is more efficient in the triple-jet system than in other jet systems. Compared with the jet Reynolds number, the jet spacing plays a more significant role in determining the critical mixing regions, while the linear relationship between them is more sensitive than that for multiple parallel plane jets

Speech Characteristics and Intelligibility in Adults with Mild and Moderate Intellectual Disabilities

PURPOSE: Adults with intellectual disabilities (ID) often show reduced speech intelligibility, which affects their social interaction skills. This study aims to establish the main predictors of this reduced intelligibility in order to ultimately optimise management. METHOD: Spontaneous speech and picture naming tasks were recorded in 36 adults with mild or moderate ID. Twenty-five naïve listeners rated the intelligibility of the spontaneous speech samples. Performance on the picture-naming task was analysed by means of a phonological error analysis based on expert transcriptions. RESULTS: The transcription analyses showed that the phonemic and syllabic inventories of the speakers were complete. However, multiple errors at the phonemic and syllabic level were found. The frequencies of specific types of errors were related to intelligibility and quality ratings. CONCLUSIONS: The development of the phonemic and syllabic repertoire appears to be completed in adults with mild-to-moderate ID. The charted speech difficulties can be interpreted to indicate speech motor control and planning difficulties. These findings may aid the development of diagnostic tests and speech therapies aimed at improving speech intelligibility in this specific group

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

Designing a stable and selective catalyst with high H2 utilisation is of pivotal importance for the direct gas-phase epoxidation of propylene. This work describes a facile one-pot methodology to synthesise ligand-stabilised sub-nanometre gold clusters immobilised onto a zeolitic support (TS-1) to engineer a stable Au/TS-1 catalyst. A non-thermal O2 plasma technique is used for the quick removal of ligands with limited increase in particle size. Compared to untreated Au/TS-1 catalysts prepared using the deposition precipitation method, the synthesised catalyst exhibits improved catalytic performance, including 10 times longer lifetime (>20 days), increased PO selectivity and hydrogen efficiency in direct gas phase epoxidation. The structure-stability relationship of the catalyst is illustrated using multiple characterisation techniques, such as XPS, 31P MAS NMR, DR-UV/VIS, HRTEM and TGA. It is hypothesised that the ligands play a guardian role in stabilising the Au particle size, which is vital in this reaction. This strategy is a promising approach towards designing a more stable heterogeneous catalyst

Billiards in a general domain with random reflections

We study stochastic billiards on general tables: a particle moves according to its constant velocity inside some domain ${\mathcal D} \subset {\mathbb R}^d$ until it hits the boundary and bounces randomly inside according to some reflection law. We assume that the boundary of the domain is locally Lipschitz and almost everywhere continuously differentiable. The angle of the outgoing velocity with the inner normal vector has a specified, absolutely continuous density. We construct the discrete time and the continuous time processes recording the sequence of hitting points on the boundary and the pair location/velocity. We mainly focus on the case of bounded domains. Then, we prove exponential ergodicity of these two Markov processes, we study their invariant distribution and their normal (Gaussian) fluctuations. Of particular interest is the case of the cosine reflection law: the stationary distributions for the two processes are uniform in this case, the discrete time chain is reversible though the continuous time process is quasi-reversible. Also in this case, we give a natural construction of a chord "picked at random" in ${\mathcal D}$, and we study the angle of intersection of the process with a $(d-1)$-dimensional manifold contained in ${\mathcal D}$.Comment: 50 pages, 10 figures; To appear in: Archive for Rational Mechanics and Analysis; corrected Theorem 2.8 (induced chords in nonconvex subdomains

Gold nanoparticles with tailored size through ligand modification for catalytic applications

The active sites of catalysts can be tuned by using appropriate organic moieties. Here, we describe a facile approach to synthesise gold nanoparticles (AuNPs) using various Au(I) precursors. The core size of these AuNPs can be precisely tailored by varying the steric hindrance imposed by bound ligands. An interesting relationship is deduced that correlates the steric hindrance around the metal to the final size of the nanoparticles. The synthesised AuNPs are immobilised onto TS-1 zeolite (Au/TS-1) with minimal change in the final size of the AuNPs. The catalytic performance of Au/TS-1 catalyst is evaluated for the direct gas phase epoxidation of propylene with hydrogen and oxygen, an environmentally friendly route to produce propylene oxide. The results indicate that smaller AuNPs exhibit enhanced catalytic activity and selectivity. Furthermore, this synthetic approach is beneficial when tailored synthesis of gold nanoparticles of specific sizes is required

Chapitre 2 • Sismique de puits

Des démarches classiquement appliquées en géophysiques d’exploration profonde, combinant différentes méthodes sismiques et diagraphiques, peuvent techniquement se décliner pour certaines reconnaissances géotechniques, hydrogéologiques ou des caractérisations de site dans le cadre d’études d’aléa sismique. Aujourd’hui la mise en œuvre de ce type de reconnaissances géophysiques est tout à fait réaliste, si les enjeux le nécessitent. Après un état de l’art concernant les mesures en forage des vitesses de cisaillement du sous-sol, appliquées au domaine géotechnique, cet ouvrage illustre la faisabilité de réaliser pour ce même domaine des profils sismiques verticaux (PSV) et des diagraphies. Cette démarche, illustre également l’intérêt de la combinaison des mesures de vitesse des formations fournies par les outils de sismique en forage (PSV) et les outils acoustiques (soniques). Un exemple innovant d’application des méthodes sismiques en forage et des diagraphies est présenté ensuite par l’étude d’un aquifère calcaire karstifié, relativement proche de la surface (de 20 à 130 m). On y montre comment une description multi échelle du réservoir peut être réalisée en intégrants les informations fournies par différentes méthodes sismiques de surface 3D-THR, diagraphies acoustiques en champs total, PSV avec hydrophones, imageries de paroi et mesures de débitmétrie. Dans cet ouvrage, les auteurs donnent également aux lecteurs des clefs pour mener à bien ces opérations, aussi bien vis-à-vis de leurs acquisitions, que de leurs traitements et interprétations. Ainsi, les utilisateurs pourront puiser l’inspiration de poursuivre la transposition de techniques pétrolières ou innovantes pour les études de la proche surface

Chapitre 3 • Diagraphie acoustique

Des démarches classiquement appliquées en géophysiques d’exploration profonde, combinant différentes méthodes sismiques et diagraphiques, peuvent techniquement se décliner pour certaines reconnaissances géotechniques, hydrogéologiques ou des caractérisations de site dans le cadre d’études d’aléa sismique. Aujourd’hui la mise en œuvre de ce type de reconnaissances géophysiques est tout à fait réaliste, si les enjeux le nécessitent. Après un état de l’art concernant les mesures en forage des vitesses de cisaillement du sous-sol, appliquées au domaine géotechnique, cet ouvrage illustre la faisabilité de réaliser pour ce même domaine des profils sismiques verticaux (PSV) et des diagraphies. Cette démarche, illustre également l’intérêt de la combinaison des mesures de vitesse des formations fournies par les outils de sismique en forage (PSV) et les outils acoustiques (soniques). Un exemple innovant d’application des méthodes sismiques en forage et des diagraphies est présenté ensuite par l’étude d’un aquifère calcaire karstifié, relativement proche de la surface (de 20 à 130 m). On y montre comment une description multi échelle du réservoir peut être réalisée en intégrants les informations fournies par différentes méthodes sismiques de surface 3D-THR, diagraphies acoustiques en champs total, PSV avec hydrophones, imageries de paroi et mesures de débitmétrie. Dans cet ouvrage, les auteurs donnent également aux lecteurs des clefs pour mener à bien ces opérations, aussi bien vis-à-vis de leurs acquisitions, que de leurs traitements et interprétations. Ainsi, les utilisateurs pourront puiser l’inspiration de poursuivre la transposition de techniques pétrolières ou innovantes pour les études de la proche surface