Three-dimensional flow structure at fixed 70° open-channel confluence with bed discordance

This experimental study provides a characterization of the flow field created by bed discordance at a fixed 70∘ open-channel confluence on the basis of detailed free surface topography and three-component acoustic Doppler velocimetry measurements, which are contrasted with the results for a concordant bed junction. Due to bed discordance, the jet-like flow from the tributary is bent downstream to be aligned with the main channel axis. Underneath the tributary backward-facing step, separation occurs, producing negative vorticity along the main channel axis. A strong secondary motion downstream of the tributary junction is related to flow separation at the step and to flow release from the jet-like flow induced by a difference in the curvature of jet-like motion. A quantification of the terms in the equation of conservation of the longitudinal vorticity shows that the vortex stretching terms are sufficient to explain the development of the helical motion, which is thus classified as a secondary motion of Prandtl's first kind.Olga Birjukova Canelas received a grant from Universidade Técnica de Lisboa (UTL) from January 2013 to February 2014 and a PhD grant [SFRH/BD/52482/2014] from the Portuguese Foundation for Science and Technology (FCT) as a part of the H2Doc Doctoral Programme. The work with ADV instrumentation and the three-axis traverse system was partially funded by FEDER, program COMPETE, and by national funds through FCT [project PTDC/ECM/118775/2010]

Thoracic high resolution computed tomography (HRCT) in asthma

INTRODUCTION: High-resolution computed tomography (HRCT) is a widespread medical imaging method for the study of thoracic diseases. In asthma it is very useful particularly when it is difficult to achieve an effective control of disease, and in severe deterioration. AIM: It was intended to evaluate the imaging changes by HRCT in asthmatic patients and to assess the expression according to the symptoms and duration of disease. MATERIAL AND METHODS: Thirty three patients from the Outpatient Department, with asthma classified in the different clinical severity stages according to GINA, were randomly included. They were submitted to HRCT (Somaton Plus-4, Siemens). The lesions were classified in reversible (mucoid impaction, acinar pattern centrilobular nodules and lobar collapse) and irreversible (bronchiectasis, bronchial wall-thickening, sequellar line shadows and emphysema). RESULTS: The 33 asthmatic patients (20 female) had an average age of 44.76 +/- 16.98 years and a mean disease evolution time of 23.39 +/-14.83 years. 30% had mild persistent asthma, 43% moderate persistent asthma and 27% severe persistent asthma. All the patients were under inhaled corticotherapy. Only 6 patients had normal HRCT 4 with mild persistent asthma (4 to 25 years of duration of disease) and 2 with moderate persistent (10 to 48 years of duration of disease). 81.81% of the patients had changes in HRCT, being the irreversible lesions the most frequent. The most important irreversible lesions were observed in severe asthma patients with longer duration of disease. All the patients with reversible lesions had also irreversible changes. Most of the bronchiectasis were centrally located and were found in severe asthma patients. Irreversible changes were identified in 3 patients with mild asthma and a maximum of 6 years of duration of disease. DISCUSSION: HRCT findings were related with asthma severity and long lasting disease but there are some asthmatics that also present early abnormalities, even in milder forms. All the groups of asthmatic patients presented all types of imaging changes, including the irreversible ones. In asthma these changes can be the result of individual patterns of response to frequent exacerbations, leading to a persistent chronic inflammatory process that will determine airway remodelling, even in early stages of disease and/or mild asthma

Spectroscopy characterization of humic acids isolated from Amazonian dark earth soils (Terra Preta De Índio).

Description and morphologic characterization; Extraction, chemical fractionation and purification of the humic material; DRIFT Spectroscopy analysis

A method for the complete analysis of NORM building materials by γ-ray spectrometry using HPGe detectors

[EN] A methodology including software tools for analysing NORM building materials and residues by low-level gamma-ray spectrometry has been developed. It comprises deconvolution of gamma-ray spectra using the software GALEA with focus on the natural radionuclides and Monte Carlo simulations for efficiency and true coincidence summing corrections. The methodology has been tested on a range of building materials and validated against reference materials

High-Throughput Top-Down Fabrication of Uniform Magnetic Particles

Ion Beam Aperture Array Lithography was applied to top-down fabrication of large dense (108–109 particles/cm2) arrays of uniform micron-scale particles at rates hundreds of times faster than electron beam lithography. In this process, a large array of helium ion beamlets is formed when a stencil mask containing an array of circular openings is illuminated by a broad beam of energetic (5–8 keV) ions, and is used to write arrays of specific repetitive patterns. A commercial 5-micrometer metal mesh was used as a stencil mask; the mesh size was adjusted by shrinking the stencil openings using conformal sputter-deposition of copper. Thermal evaporation from multiple sources was utilized to form magnetic particles of varied size and thickness, including alternating layers of gold and permalloy. Evaporation of permalloy layers in the presence of a magnetic field allowed creation of particles with uniform magnetic properties and pre-determined magnetization direction. The magnetic properties of the resulting particles were characterized by Vibrating Sample Magnetometry. Since the orientation of the particles on the substrate before release into suspension is known, the orientation-dependent magnetic properties of the particles could be determined

Testing Biochemistry Revisited: How In Vivo Metabolism Can Be Understood from In Vitro Enzyme Kinetics

A decade ago, a team of biochemists including two of us, modeled yeast glycolysis and showed that one of the most studied biochemical pathways could not be quite understood in terms of the kinetic properties of the constituent enzymes as measured in cell extract. Moreover, when the same model was later applied to different experimental steady-state conditions, it often exhibited unrestrained metabolite accumulation