Search results for "Guide"

Obstructing propagation of interfering modes improves detection of guided waves in coated bone models

2014

Interference due to wave propagation in soft tissue that covers the bone is a major challenge to in vivo assessment of the fundamental flexural guided wave (FFGW) in bone. To improve signal-to-interference ratio (SIR) we propose to obstruct the propagation of interfering modes by locally deforming the coating by external mechanical compression. This approach was modeled by 2D finite-element transient domain (FEMTD) simulations in a fluid-coated (7 mm) solid plate (3 mm). The fluid layer mimics the soft tissue that covers the bone. A single emitter or a 6-element phased array excited ultrasound pulses at 50 kHz on the surface of the coating, and a receiver array was placed on the surface, 20…

2D Waveguided Bessel Beam Generated Using Integrated Metasurface-Based Plasmonic Axicon.

2020

International audience; Near-field imaging of the propagation of a diffraction-free Bessel-type beam in a guided wave configuration generated by means of a metasurface-based axicon lens integrated on a silicon waveguide is reported. The operation of the axicon lens with a footprint as small as 11 μm2 is based on local engineering of the effective index of the silicon waveguide with plasmonic nanoresonators. This generic approach, which can be adapted to different types of planar lightwave circuit platforms, offers the possibility to design nano-engineered optical devicesbased on the use of plasmonic resonators to control light at the nanoscale.

Global–local model for three-dimensional guided wave scattering with application to rail flaw detection

2021

This study presents a three-dimensional global–local formulation for the prediction of guided wave scattering from discontinuities (e.g. defects). The approach chosen utilizes the Semi-Analytical Finite Element method for the “global” portion of the waveguide, and a full Finite Element discretization for the “local” portion of the waveguide containing the discontinuity. The application of interest is the study of guided wave scattering from transverse head defects in rails. Theoretical scattering results are impossible to obtain in this case for a wide-frequency range. While three-dimensional Semi-Analytical Finite Element–Finite Element models for guided wave scattering studies have been …

Detection of disbonds in multilayer structures by laser-based ultrasonic technique

2008

Adhesively bonded multi-layer structures are frequently used, mostly in the aerospace industry, for their structural efficiency. Nondestructive evaluation of bond integrity in these types of structures, both after manufacturing and for periodic inspection during service, is extremely important. A laser-based ultrasonic technique has been evaluated for non-contact detection of disbonds in aluminum multi-layer structures. Two configurations have been used to detect disbonded areas: pitch-catch with unidirectional guided wave scan and through-transmission with bidirectional scan. Guided wave scanning was done with a laser line source and air-coupled transducer sensing at 500 kHz, 1 ;MHz, and 2…

Progress Report The ItalianSocietyofGastroenterology(SIGE)andtheItalianGroupforthestudy of InflammatoryBowelDisease(IG-IBD)ClinicalPracticeGuidelines…

2011

Biological therapiesareanimportantstepinthemanagementofInflammatoryBowelDiseases.Incon- sideration ofhighcostandsafetyissuesthereistheneedtohaveclearrecommendationsfortheiruse. Despite theAmericanGastroenterologicalAssociationandtheEuropeanCrohn’sandColitisOrganisation have publishedexhaustiveInflammatoryBowelDiseaseguidelines,nationalguidelinesmaybeneces- sary asculturalvalues,economicalandlegalissuesmaydifferbetweencountries.Forthesereasonsthe Italian SocietyofGastroenterologyandtheItalianGroupforthestudyofInflammatoryBowelDisease have decidedtoelaboratetheItalianguidelinesontheuseofbiologicsinInflammatoryBowelDisease. The followingitemshavebeenchosen:definitionsofactive,inactive,steroidd…

Study of new tellurite glasses in the TeO2-ZnO-La2O3 (TZL) system for the manufacturing of mid-infrared multimaterial optical fibers and specialty op…

2023

This thesis work was carried out using tellurite glasses from the TeO2-ZnO-La2O3 (TZL) ternary diagram for optical fibers manufacturing. The choice to use this system is motivated by the ambition to improve the transmission of optical signals within oxide glasses for which absorption bands related to OH groups are present in the transparency window. A structural study is first carried out on these glasses by Raman spectroscopy in order to understand the influence of the composition on physicochemical properties (especially on optical and thermal properties) but also to estimate the ability of a vitreous matrix to reorganize when subjected to a thermal solicitation such as the preform-to-fib…

Tourisme Sportif et Identités : Les pratiquants de canoë en Zambie

2013

Cet article repose sur une enquête sur les usages sociaux du canoë en Zambie. Il a pour objectif de décrire les caractéristiques des relations sociales qui se nouent entre étrangers et « populations locales ». Si l’organisation de l’activité recouvre une visée touristique pour nombre de pays africains, touristes et habitants entrent peu en interaction en dehors de la pratique des loisirs. Pour étudier l’identité, il s’agit de caractériser la genèse du tour en canoë afin de saisir l’émergence de modes d’appréhension de l’Autre dans le cadre du loisir en Zambie. La singularité des relations sociales entre populations occidentales et africaines pose la question de la différence culturelle, au …

Thirty-five years later, the first assisted reproductive technology program opens in Cambodia

2015

Antithrombotische Therapie bei peripherer arterieller Verschlusskrankheit

2018

Was ist neu? Antithrombotische Therapie bei stabiler PAVK Die aktuellen deutschen und europäischen Leitlinien empfehlen bei Patienten mit einer peripheren arteriellen Verschlusskrankheit (PAVK) die Monotherapie mit einem Thrombozytenaggregationshemmer (ASS 100 mg oder Clopidogrel 75 mg).In der COMPASS (Cardiovascular OutcoMes for People using Anticoagulation StrategieS) -Studie wurde Patienten mit PAVK 2 × 2,5 mg Rivaroxaban zusätzlich zu ASS 100 mg gegeben. Dies führte zur signifikanten Reduktion kardiovaskulärer Ereignisse (MACE = Major Adverse Cardiovascular Events) wie kardiovaskulärer Tod, Myokardinfarkt und Schlaganfall. Ebenfalls signifikant reduziert wurden periphere Ereignisse (MAL…

Entwicklung eines ICF-basierten Leitfadens für die Beurteilung funktioneller Aspekte bei Kopf-Hals-Tumoren

2013

Funktionelle Beeintrachtigungen bei Kopf-Hals-Tumoren werden bisher im klinischen Alltag selten standardisiert erhoben. Klinische Studien mit der Zielgrose Funktionserhalt bei KHT verwenden viele verschiedene Instrumente. Die Ergebnisse sind deshalb oft schlecht vergleichbar und lassen zu wenig klinische Schlussfolgerungen zu. Es war daher notwendig und Ziel dieser Studie, die nach bisheriger Evidenz und interdisziplinarem Expertenkonsens am besten geeigneten Instrumente zur Beurteilung von Funktionsfahigkeit bei KHT zu identifizieren und Empfehlungen fur deren Verwendung in einem Leitfaden zusammenzustellen. In Vorstudien wurde unter Verwendung festgelegter Kriterien eine Vorauswahl an Ins…