A new approach for scaling beach profile evolution and sediment transport rates in distorted laboratory models

Laboratory wave flume experiments in coastal engineering and physical oceanography are widely used to provide an improved understanding of morphodynamic processes. Wave flume facilities around the world vary greatly in their physical dimensions and differences in the resulting distortion of the modelled processes are reconciled using scaling laws. However, it is known that perfect model-prototype scaling of all hydro and morphodynamic processes is rarely possible and there is a lack of understanding to what extent distorted models can be used for direct morphological comparison. To address this issue, distorted scale laboratory flume experiments were undertaken in three different facilities, with the aim to measure and compare beach profile evolution under erosive waves and increasing water levels. A novel approach was developed to transform and scale the different experimental geometries into dimensionless coordinates, which enabled a direct quantitative comparison of the beach profile evolution and sediment transport rates between the differing distorted experimental scales. Comparing results from the three experiments revealed that the dimensionless scaled morphological behaviour was similar after the same number of waves – despite very different degrees of model distortion. The distorted profiles appeared to be suitable for comparison as long as a modified version of the Dean number is maintained between them. The new method was then validated with two further published datasets, and showed good agreement for both dimensionless profile shape, dimensionless sediment transport and morphodynamics parameters. The new approach scales the sediment transport by the square of the runup, proportional to HL, rather than H2, and yields good agreement between the datasets. It is further shown that the new scaling method is also applicable for comparing distorted profile evolution under water level increase, as long as the water level is raised in a similar way between the experiments and by the same total increment relative to the significant wave height (Δh/Hs).</p

A new approach for scaling beach profile evolution and sediment transport rates in distorted laboratory models

Laboratory wave flume experiments in coastal engineering and physical oceanography are widely used to provide an improved understanding of morphodynamic processes. Wave flume facilities around the world vary greatly in their physical dimensions and differences in the resulting distortion of the modelled processes are reconciled using scaling laws. However, it is known that perfect model-prototype scaling of all hydro and morphodynamic processes is rarely possible and there is a lack of understanding to what extent distorted models can be used for direct morphological comparison. To address this issue, distorted scale laboratory flume experiments were undertaken in three different facilities, with the aim to measure and compare beach profile evolution under erosive waves and increasing water levels. A novel approach was developed to transform and scale the different experimental geometries into dimensionless coordinates, which enabled a direct quantitative comparison of the beach profile evolution and sediment transport rates between the differing distorted experimental scales. Comparing results from the three experiments revealed that the dimensionless scaled morphological behaviour was similar after the same number of waves – despite very different degrees of model distortion. The distorted profiles appeared to be suitable for comparison as long as a modified version of the Dean number is maintained between them. The new method was then validated with two further published datasets, and showed good agreement for both dimensionless profile shape, dimensionless sediment transport and morphodynamics parameters. The new approach scales the sediment transport by the square of the runup, proportional to HL, rather than H2, and yields good agreement between the datasets. It is further shown that the new scaling method is also applicable for comparing distorted profile evolution under water level increase, as long as the water level is raised in a similar way between the experiments and by the same total increment relative to the significant wave height (Δh/Hs).</p

PENERAPAN MODEL EXPLICIT INSTRUCTION PADA PEMBELAJARAN SENI TARI UNTUK MENINGKATKAN MINAT BELAJAR SISWA.

Judul penelitian ini adalah Penerapan Model Explicit Instruction Pada Pembelajaran Seni Tari Untuk Meningkatkan Minat Belajar Siswa (Studi Eksperimen Pada Siswa Kelas VIII-F SMP Negeri 3 Lembang). Permasalahan yang diangkat ialah bagaimana menumbuhkan minat belajar siswa melalui pembelajaran tari dengan tiga pertanyaan penelitian diantaranya, (1) Bagaimana minat belajar siswa terhadap pembelajaran seni tari sebelum diterapkannya model Explicit Instruction di kelas VIII-F SMP Negeri 3 Lembang?, (2) Bagaimana proses pembelajaran untuk meningkatkan minat belajar siswa terhadap pembelajaran seni tari melalui model Explicit Instruction di kelas VIII-F SMP Negeri 3 Lembang?, (3) Bagaimana hasil pembelajaran Seni Tari untuk meningkatkan minat belajar siswa setelah diterapkannya model Explicit Instruction dikelas VIII-F SMP Negeri 3 Lembang?. Metode penelitian yang digunakan adalah metode eksperimen pendekatan kuantitatif dan teknik pengumpulan data diantaranya studi pustaka, observasi, wawancara, tes, dan dokumentasi. Hasil analisis data dan temuan mengenai minat belajar siswa sebelum menggunakan model explicit instruction sangat rendah karena model pembelajaran yang digunakan belum tepat, peningkatan minat terlihat pada saat proses pembelajaran, kemudian uji t tabel yang menyatakan bahwa t_tes 4 > t_tab1,729. Hal ini membuktikan bahwa model explicit instruction sangat signifikan untuk meningkatkan minat belajar siswa dan dapat di jadikan sebagai salah satu rekomendasi untuk pembelajaran tari terutama dalam meningkatkan minat belajar siswa

Correction: Enhancing carrier generation in TiO2 by a synergistic effect between plasmon resonance in Ag nanoparticles and optical interference

Silver nanoparticles have been embedded at a few nanometer distance from the free surface of titania/silica multilayers using low energy ion beam synthesis. Transmission electron microscopy shows the presence of 3 nm-sized crystalline particles. Reflectance spectroscopy on these composite substrates shows an increase of the light capture efficiency in the visible range. This behaviour is interpreted as a synergistic effect between plasmon polariton resonance and Fabry–Perot interferences. Plasmon-resonant Raman spectroscopy is deeply used to analyze, on one hand confinement of vibrations and electronic excitations in Ag NPs, and on the other hand coupling of polar TiO2 phonons with injected photo-generated carriers. It is shown how these new Ag/TiO2 nanocomposite films appear as very promising to enhance the efficiency and enlarge the spectral sensitivity of plasmo-electronics devices

Buffer layers inhomogeneity and coupling with epitaxial graphene unravelled by Raman scattering and graphene peeling

The so-called buffer layer (BL) is a carbon rich reconstructed layer formed during the sublimation of SiC (0001). The existence of covalent bonds between some of the carbon atoms in this layer and the underlying silicon atoms makes it different from epitaxial graphene. We report a systematical and statistical investigation of the BL signature and its coupling with epitaxial graphene by Raman spectroscopy. Three different kinds of BLs are studied: bare buffer layer obtained by direct growth (BL 0), interfacial buffer layer situated between graphene and SiC (c-BL 1) and the interfacial buffer layer without graphene above (u-BL 1). To obtain the latter, we develop a mechanical exfoliation of graphene by depositing and subsequently removing an epoxy-based resin or nickel layer. The observed BLs are ordered-like on the whole BL growth temperature range. BL 0 Raman signature may vary from sample to sample but also forms patches on the same terrace. u-BL 1 share similar properties with BL 0 , albeit with more variability. These BLs have a strikingly larger overall intensity than BL with graphene on top. The signal onset on the high frequency side upshifts upon graphene coverage, that cannot be explained by a simple strain effect. Two fine peaks situated at 1235 and 1360 cm-1 are present for epitaxial monolayer while absent for BL and transferred graphene. These findings point to a coupling between graphene and BL

Substrate transfer and ex situ characterization of on-surface synthesized graphene nanoribbons

Recent progress in the on-surface synthesis of graphene nanoribbons (GNRs) has given access to atomically precise narrow GNRs with tunable electronic band gaps that makes them excellent candidates for room-temperature switching devices such as field-effect transistors (FET). However, in spite of their exceptional properties, significant challenges remain for GNR processing and characterization. This contribution addresses some of the most important challenges, including GNR fabrication scalability, substrate transfer, long-term stability under ambient conditions and ex situ characterization. We focus on 7- and 9-atom wide armchair graphene nanoribbons (i.e, 7-AGNR; and 9-AGNR) grown on 200 nm Au(111)/mica substrates using a high throughput system. Transfer of both, 7- and 9-AGNRs from their Au growth sub-strate onto various target substrates for additional characterization is accomplished utilizing a polymer-free method that avoids residual contamination. This results in a homogeneous GNR film morphology with very few tears and wrinkles, as examined by atomic force microscopy. Raman spectroscopy indicates no significant degradation of GNR quality upon substrate transfer, and reveals that GNRs have remarkable stability under ambient conditions over a 24-month period. The transferred GNRs are analyzed using multi-wavelength Raman spectroscopy, which provides detailed insight into the wavelength dependence of the width-specific vibrational modes. Finally, we characterize the optical properties of 7- and 9-AGNRs via ultra-violet-visible (UV-Vis) spectroscopyComment: 30 pages, 14 figure

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Architectures plasmoniques enterrées : élaboration, propriétés optiques et applications

In our work, we present the study of plasmonic architectures made of a plane of nanoparticules (NPs) embedded at the vicinity of a dielectric matrix free surface, by low energy ion beam synthesis. Materials structural analysis, especially by transmission electron microscopy, have been carried out to determine the impact of the elaboration process parameters on the three dimensional organization of the NPs, in silicon dioxide or nitride layers grown on silicon substrates. To systematically check these parameters, we studied the elastic and inelastic optical responses of the heterostructures. The elastic response has been obtained by measuring the reflectance of the samples, and confronted to numerical modelling we developed, to determine the mean size of the NPs and the implanted silver amount. The study of the electric field topography allowed us to take benefit from both plasmonic resonance and optical amplification in antireflective layers. The inelastic response has been studied using Raman spectroscopy over a wide frequency range: vibrational collective modes (Lamb modes) of the NPs have been studied at low frequency, while at higher frequency, we have extracted the vibrational density of states (VDOS). Combined with atomistic simulations, the VDOS gave us original information on the vibrational dynamics and the thermodynamic properties of buried silver NPs (and deposited gold NPs). Finally, we present some applications of the assemblies of NPs in hybrid devices, such as the use of coupling between these NPs and deposited substances (e.g. graphene) on our substrates. In particular, it can be used for surface enhanced Raman spectroscopy (SERS). Then using techniques from microelectronics, we designed plasmo-electronic devices exploiting photoconductance properties of these buried or deposited NPs assemblies.Dans notre travail, nous présentons une étude d’architectures plasmoniques à base d’assemblées planes de nanoparticules (NPs) d’argent, enterrées à quelques nanomètres sous la surface d'une matrice diélectrique. L’analyse structurale des matériaux, notamment par microscopie électronique en transmission, a été menée pour déterminer le rôle des différents paramètres de la technique d’élaboration, l’implantation ionique à basse énergie, sur l’organisation à trois dimensions des NPs, dans des films de dioxyde ou de nitrure de silicium sur substrat de silicium. Afin de contrôler de manière systématique ces paramètres, nous avons étudié les réponses optiques élastique et inélastique des hétérostructures. La réponse optique élastique a été obtenue grâce à des mesures de réflectance optique, puis confrontée à des simulations numériques que nous avons développées afin de déterminer la taille moyenne des NPs et la quantité d’argent implantée. L’étude de la topographie du champ électrique a ainsi permis de tirer profit à la fois de la résonnance plasmonique et de l’amplification optique dans nos systèmes multicouches antireflet. La réponse inélastique a quant à elle été étudiée grâce à la spectrométrie Raman sur une large gamme de fréquence. Les modes collectifs de vibration (dits de Lamb) des NPs ont été analysés à basse fréquence, et à plus haute fréquence, nous avons extrait la densité d’états des modes de vibration (VDOS). Associée à des simulations atomistiques, celle-ci nous a donné des informations originales sur la dynamique vibrationnelle à l’échelle atomique et les propriétés thermodynamiques de NPs d’argent enterrées (mais également de NPs d’or déposées). Enfin, nous montrons plusieurs exemples d’applications des assemblées de NPs dans des dispositifs hybrides comme l’exploitation des couplages entre ces NPs et des dépôts (notamment de graphène) réalisés sur nos substrats. En particulier, ceux-ci peuvent être exploités pour la spectrométrie exaltée de surface (effet SERS). Puis nous avons conçu, grâce aux techniques de microélectronique, des dispositifs de plasmo-électronique exploitant les propriétés de photoconductance de ces assemblées de NPs, déposées ou enterrées

Plasmon-enhanced inelastic scattering by 2D and 3D superlattices made of silver nanocrystals

International audienc

Des learning and learning in an organization: a tool in a global world

Las empresas en la actualidad están direccionando sus recursos no solo al logro de objetivos y nuevas tecnologías, lo hacen también al desarrollo integral del recurso humano, con el fin de tener una empresa sólida y generar capital intelectual y renovable dentro de la misma, con capacidad competitiva para desafiar en el mercado global. El mercado ha cambiado nos encontramos en un nuevo esquema global, donde el panorama administrativo, comercial y gerencial debe transformase para competir ya que solo los más fuertes pueden sobrevivir y sobresalir. Es importante entender entonces, que el desarrollo de capacidades hace más fuerte a la persona, pero de igual manera a la organización.Companies today are managing its resources not only to the achievement of objectives and new technologies, also make the integral development of human resources, in order to have a solid business and generate intellectual and renewable capital within the same, with capacity to challenge competitive in the global market. The market has changed we are in a new global scheme, where the administrative, commercial and managerial panorama must transform to compete as only the strongest can survive and excel. It is important to understand then that the capacity grows stronger person, but equally to the organization.Pregrad