Ultrasonic Propagation in Liquid and Ice Water Drops. Effect of Porosity.

This work studies ultrasonic propagation in liquid and ice water drops. The effect of porosity on attenuation of ultrasonic waves in the drops is also explored. The motivation of this research was the possible application of ultrasonic techniques to the study of interstellar and cometary ice analogs.

Ultrasound Transmission Tomography for Detecting and Measuring Cylindrical Objects Embedded in Concrete.

This study explores the feasibility of using transmission tomographic images based on attenuation measures in transmission to detect and estimate the most common materials that are embedded in concrete, reinforcements and natural and artificial voids. A limited set of concrete specimens have been made in which cylindrical objects such as bars/tubes of steel, PVC and aluminium have been embedded to analyse the effect of size and material. The methodology and scope of this study is presented and numerical simulations are carried out to optimize the emitter-receiver configuration and to understand the complex physical propagation phenomena of ultrasonic signals that travel through concrete with embedded inclusions.

Structural and Luminescence Properties of Lu₂O₃:Eu F127 Tri-Block Copolymer Modified Thin Films Prepared by Sol-Gel Method.

Lu₂O₃:Eu transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation.

Preparation and scintillating properties of Sol-Gel Eu(3+), TB(3+) co-doped Lu(2)O(3) nanopowders.

Nanocrystalline Eu(3+), Tb(3+) co-doped Lu(2)O(3) powders with a maximum size of 25.5 nm were prepared by the sol-gel process, using lutetium, europium and terbium nitrates as precursors, and ethanol as a solvent. Differential thermal analysis (DTA) and infrared spectroscopy (IR) were used to study the chemical changes during the xerogel annealing.

[Open acess to endoscopy in a tertiary referal center].

Objective: The purpose of this study was to determine the yield of open access endoscopy in a third level Mexican hospital.

Background Data: Open access endoscopy is common in United States of America and Europe (endoscopy is performed without prior specialist consultation). In Mexico this system hasn't become popular yet.