856 research outputs found
High-attitude low-speed static aerodynamic characteristics of an F-4D fighter airplane model with leading edge slats
An investigation was conducted to determine the effects of two-position leading edge slats on the low speed aerodynamic characteristics of a swept wing twin-jet supersonic fighter airplane model at high angle of attack and various Reynolds numbers. The investigation was performed at a Mach number of 0.20 over a range of angle of attack from 19 deg to 90 deg and angles of slideslip from -10 deg to 30 deg and Reynolds numbers from 1.97 to 13.12 million per meter
Real convergence in Europe: a cluster analysis
In this paper we analyse real convergence in GDP per worker in the EU member states. The aim is to test whether there is evidence of club convergence in the EU, i.e. divergence in GDP per worker. Evidence in favour of cluster or club convergence may be an indication of significant productivity divergences between countries, which may also explain the current turmoil in the euro zone. The results show evidence of different economic growth rates within Europe, which also converge to different steady states, implying divergence in the EU-14. Within the EU-14 member states we observe two convergence clubs, which are not related to the fact that some countries belong to the euro area. Furthermore, Eastern European countries are also divided in two clubs, with a more direct effect of belonging to the euro zone in the composition of the clubs
Tourist spaces and tourism policy in Spain and Portugal
Advances in Cultura, Tourism and Hospitality Research;10, 235-249This study analyses the relationship between the development of the tourism policy of Spain and Portugal and their effects on regional imbalances. Despite the proximity of the two countries and their specialisation in tourism, there are few comparative studies on tourism of the two Iberian countries. The study focuses on the two major phases of tourism policy: the period of mass tourism and post-Fordist stage. In the conclusions we refer the debate on the existence of a model of development based on tourism to the Latin countries of Southern Europe and we note the export process of the Spanish low-cost tourism model to other countries.Financiado por el Gobierno de España, Programa Fundamental de Investigación, Proyecto de I+D (CSO2012-30840) "Geografías de la crisis: análisis de los territorios urbanos y turísticos de las Islas Baleares, Costa del Sol y principales destinos del Caribe y América Central"
Reduction of CO2-emissions in ceramic tiles manufacture by combining energy-saving measures
Ceramic tile manufacture requires a great quantity of energy, mainly in the form of heat.
The heat is principally used in the kilns and dryers, and it is obtained by natural gas
combustion.
The increasing cost of natural gas, as well as the application of a new gas tax, the new
legislation in regard to emissions trading, and the difficult current economic situation
have driven the ceramic tile sector to implement energy-saving actions in the production
process with the twofold aim of reducing energy costs and abating carbon dioxide
emissions.
One such course of action is the European project REDUCER, funded by the European
Commission and led by Azulev S.A.U., in which the Instituto de Tecnología Cerámica
(ITC) also participates. This project seeks to implement energy-saving actions in
company kilns and dryers in order to lower natural gas consumption and reduce carbon
dioxide emissions in the tile manufacturing process.
One of the saving actions envisaged is the installation of a system of waste heat recovery
from one of the company kilns to the tile body dryers. This new waste heat recovery
system is to be added to and will complement the already existing system at the
company, thus achieving maximum heat recovery from the kiln stacks. The recovered
heat will go entirely to the green tile body dryers, thus reducing natural gas consumption
in the dryers.
The designed installation seeks to recover 600 kW heat from the stacks of one of the
kilns, entailing a natural gas saving of more than 120 k€/year and suppressing the
emission into the atmosphere of 720 tons of CO2/year, savings that are to be added to
those attained with other energy-saving measures.
This paper describes the energy-saving actions implemented at the company, as well as
the resulting energy savings
What is the initiation step of the Grubbs-Hoveyda olefin metathesis catalyst?
Density function theory calculations reveal that the Grubbs-Hoveyda olefin metathesis pre-catalyst is activated by the formation of a complex in which the incoming alkene substrate and outgoing alkoxy ligand are both clearly associated with the ruthenium centre. The computed energies for reaction are in good agreement with the experimental values, reported here
Quantifying hypoxia with diffuse reflectance spectroscopy for advanced prognostication and real-time response monitoring in rectal cancer: an in vivo feasibility study
Tumour hypoxia is a critical factor in treatment failure and resistance, and its accurate measurement with diffuse reflectance spectroscopy (DRS) could be used for prognostic and response monitoring purposes. In this in vivo characterisation study, we sequentially measured oxygenation trends over the entire course of tumour growth in mice using a multi-depth, fibre-optic DRS probe. Results demonstrated a clear downtrend in oxygenation over time. This progression was not always linear, with significant heterogeneity over time and between mice. Our findings will be further validated against gold standards prior to investigating whether hypoxia can be used to predict radiotherapy responses
Functional magnetic resonance imaging evaluation of pain central sensitization phenomena in subjects with knee osteoarthritis
Lumen shape reconstruction using a soft robotic balloon catheter and electrical impedance tomography
Incorrectly sized balloon catheters can lead to increased post-surgical complications, yet even with preoperative imaging, correct selection remains a challenge. With limited feedback during surgery, it is difficult to verify correct deployment. We propose the use of integrated impedance measurements and Electrical Impedance Tomography (EIT) imaging to assess the deformation of the balloon and determine the size and shape of the surrounding lumen. Previous work using single impedance measurements, or pressure data and analytical models, whilst demonstrating high sizing accuracy, have assumed a circular cross section. Here we extend these methods by adding a multitude of electrodes to detect elliptical and occluded lumen and obtain EIT images to localise deformations. Using a 14 Fr (5.3 mm) catheter as an example, numerical simulations were performed to find the optimal electrode configuration of two rings of 8 electrodes spaced 10 mm apart. The simulations predicted that the maximum detectable aspect ratio decreased from 0.9 for a 14mm balloon to 0.5 at 30mm. The sizing and ellipticity detection results were verified experimentally. A prototype robotic balloon catheter was constructed to automatically inflate a compliant balloon while simultaneously recording EIT and pressure data. Data were collected in experiments replicating stenotic vessels with an elliptical and asymmetrical profile, and the widening of a lumen during angioplasty. After calibration, the system was able to correctly localise the occlusion and detect aspect ratios of 0.75. EIT images further localised the occlusion and visualised the dilation of the lumen during balloon inflation
A compact fluorescence sensor for low-cost non-invasive monitoring of gut permeability in undernutrition
Undernutrition is associated with approximately 45% of deaths among children under the age of 5. Furthermore, in 2020, around 149 million children suffered impaired physical/cognitive development due to lack of adequate nutrition. Environmental enteropathy (EE) is associated with undernutrition and is characterized by a multifaceted breakdown in gut function, including an increase in intestinal permeability that can lead to inflammatory responses. However, the role and mechanisms associated with EE (particularly gut permeability) are not well understood. This is partly because current techniques to assess changes in gut permeability, such as endoscopic biopsies, histopathology and chemical tests such as Lactulose:Mannitol assays, are either highly invasive, unreliable or difficult to perform on specific groups of patients (such as infants and patients with urine retention problems). Therefore, low-cost, non-invasive and reliable diagnostic tools are urgently needed for better evaluation of intestinal permeability. Here, we present a compact transcutaneous fluorescence spectroscopy sensor for non-invasive evaluation of gut permeability and report the first in vivo data collected from volunteers in an undernutrition trial. Using this technique and device, fluorescence signals are detected transcutaneously after oral ingestion of a fluorescent solution. Preliminary results demonstrate the potential use of the presented sensor for clinical assessment of gut permeability in low-income settings
¿Como podemos anallizar la competencia narrativa del alumnado en el aprendizaje de la historia?
The aim of this paper is to analyze the role that teachers assigned to curricular requirements,
establishing the relationship between these documents and everyday practice. From the
interpretation of interviews with a group of teachers, is to study the ways in which teachers
used, discarded and/or reworked curriculum requirements, based on assume that they have
an active role in the redefinition of such documents. The research results indicate that the
new meanings and adaptations that teachers do in the written standard change according to
different courtly and contextual realities
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