1,716 research outputs found

    On balancedness and D-Completeness of the space of Semi-lipschitz functions

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    Let (X, d) be a quasi-metric space and (Y, q) be a quasi-normed linear space. We show that the normed cone of semi-Lipschitz functions from (X, d) to (Y, q) that vanish at a point x0 E X, is balanced. Moreover, it is complete in the sense of D. Doitchinov whenever (Y, q) is a biBanach spac

    Influence of process parameters on the corrosion resistance of corrugated austenitic and duplex stainless steels

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    The main objective of this work is to study the influence of the forming process on two corrugated, lean, duplex stainless steels (DSSs): UNS S32001 and UNS S32304. Both grades have been recently proposed as alternative materials to the austenitic UNS S30403 grade for manufacturing reinforcement bars to be embedded in concrete structures, exposed to corrosive environments. Hot-worked (HW) corrugated bars of both DSSs are analyzed and their corrosion behaviour is compared with that of the HW and cold-worked (CW) corrugated bars of S30403. The corrosion performance is characterized through cyclic polarization curves in 8 different solutions that simulate those contained inside the pores of concrete in different circumstances. The obtained results justify a great interest in the studied lean DSS grades with respect to their use as reinforcements. Moreover, it is proved that the corrugated surface of a bar is clearly less corrosion resistant than the centre of the bar. The processing method of producing reinforcements influences not only the pitting susceptibility but also the pitting morphology.Publicad

    Investigating Piezochromic Properties of πconjugated Materials: a combined Raman and DFT Study

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    Π-conjugated materials have been studied for decades due to their great interest in organic electronics. Among them, piezochromic materials, which exhibit color changes resulting from external pressure or mechanical grinding, become very attractive from a scientific viewpoint owing to their potential applications as pressure-sensing and opticalrecording systems1. The main target of the present work is to develop a joint experimental and theoretical approach able to deliver crucial information for the understanding of the structural effects causing piezochromic changes. To this end, we will focus our attention on two families of -conjugated materials with potential application as sensors. The first one is a family of 9,10-Bis((E)-n(pyrid-2-yl)vinyl) anthracene, BPnVA (n=2 orto-,3 metha- and 4 para-) compounds, see Figure 1. Interestingly, these three compounds with varying position of the nitrogen on the external pyridyl group exhibit different molecular packing modes. Grinding and the application of external pressure on the powder also led to a strong change in their photoluminescence color.2 The second familiy is based on the N,N’-Bis-Boc-3,3’-di(pyren-1yl)-2,2’-biindole compound (compound 1c in Figure 1) which also shows photoluminescence under pressure application. However, the molecular packing induced by this phenomenon is still under study 3. In both cases, it will be also very interesting to determine how temperature affects the vibrational structure of these systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Influence of relative humidity on the carbonation of calcium hydroxide nanoparticles and the formation of calcium carbonate polymorphs

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    A consolidating product based on nanoparticles of slaked lime (Ca(OH)2) dispersed in isopropyl alcohol was exposed under different relative humidities (RH), 33%, 54%, 75% and 90% during 7, 14, 21 and 28days. The characterization of the calcium hydroxide nanoparticles and the formed calcium carbonate polymorphs have been performed by Micro Raman spectroscopy, Transmission Electron Microscopy (TEM), Environmental Scanning Electron Microscopy (ESEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). Precipitation and transformation of calcium carbonate polymorphs strongly depend on the relative humidity (RH). Higher RH (75%-90% RH) gives rise to amorphous calcium carbonate and monohydrocalcite, calcite, aragonite and vaterite, faster carbonation and larger particles sizes with higher crystallinity compared to lower RH (33%-54% RH) that gives rise mainly to portlandite and vaterite, slower carbonation and smaller particle sizes with lower crystallinity. © 2010 Elsevier B.V.This study was funded by the Government of the Community of Madrid by GEOMATERIALES (S2009/MAT-1629) and CONSOLIDERTCP (CSD2007-0058) and to the JAE-Doc CSIC contracts for supporting P. López-Arce and L.S. Gómez-Villalba to develop this work.Peer Reviewe

    Welded, sandblasted, stainless steel corrugated bars in non-carbonated and carbonated mortars: A 9-year corrosion study

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    Three different stainless steel corrugated grades (UNS S20430, S30403 and S32205) were similar welded to stainless steel bars with the same composition and dissimilar welded to carbon steel (CS). After cleaning the welding oxides by sandblasting, the reinforcements were embedded in mortar with chlorides and some of the samples were carbonated. Corrosion activity was monitored using corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS). After 8 years of exposure, the samples were anodically polarized. Visual evaluation of the attack was performed after another additional year of exposure. Similar welded stainless steels offer a good durability if they have been sandblasted, except for S20430 when it is embedded in carbonated mortar with chlorides. Dissimilar welded steels are active since the beginning of the exposure for both studied conditions, but sandblasting reduces the corrosion rate of CS compared to non-welded CS bars.The present work was funded by the Spanish Ministry of Science and Innovation through the Project reference BIA2007-66491-C02-02

    Corrugated stainless steels embedded in mortar for 9 years: corrosion results of non-carbonated, chloride-contaminated samples

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    Mortar samples reinforced with 5 different corrugated stainless steels were tested for 9 years in 2 different conditions: partial immersion (PI) in 3.5% NaCl, and chloride addition to the mortar and exposure to high relative humidity (HRH). The monitoring during the exposures was carried out with corrosion potential (E-corr) and electrochemical impedance spectroscopy (EIS) measurements. A year before finishing (after 8 years of exposure), the reinforced mortar samples were anodically polarised to obtain more information about the pitting resistance of the passive layers formed under the different conditions. The last year of exposure was established to study the progress or repassivation of the pits. The PI is the most aggressive testing condition and it causes low-intensity corrosion in S20430 austenitic stainless steel after 7 years of exposure. The S32205 duplex stainless steel shows very good corrosion behaviourThe present work was funded by the Spanish Ministry of Science and Innovation through the Project reference BIA2007 66491 C02 02

    Asthma diagnosis is not associated with obesity in a population of adults from Madrid

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    Background: Several studies have suggested a relationship between asthma and obesity; however, this relationship is unclear when obesity is compared with bronchial hyperresponsiveness to methacholine. Aim: To determine whether obesity is associated with a diagnosis of asthma. Methods: We conducted a cross-sectional study in a population of Spanish adults in the north of Madrid, Spain between 2003 and 2007. The patients included had experienced asthma symptoms during the previous year, but had a ratio of forced expiratory volume in the fi rst second of expiration (FEV1) to forced vital capacity (FVC) of >70%. Diagnosis was confi rmed by the presence of symptoms and demonstration of bronchial hyperresponsiveness to methacholine. Obesity was measured by body mass index (BMI). Adjusted odd ratios (OR) were obtained by logistic regression. Results: Of a total of 1424 patients included, 251 (17.6%) were diagnosed with asthma. These patients were younger (P<.001) and had lower BMI (P<.001) and lung function parameters (FEV1 and FEV1/FVC ratio) than individuals without asthma (P<.001). After adjusting the model for age, gender, baseline FEV1, and FEV1/FVC ratio, patients with overweight or obesity were not more frequently diagnosed with asthma than those with normal weight (OR, 0.848 [95% confi dence interval (CI), 0.59-1.20]; and OR, 0.616 [95% CI, 0.38-0.99], respectively). In addition, obese males were more frequently diagnosed with asthma than obese females (P<.041). Conclusions: In this study, obesity and overweight were not associated with a diagnosis of asthma based on the presence of consistent symptoms and demonstration of airway responsiveness to methacholineFundamento: Varios estudios sugieren que la obesidad es un factor de riesgo para padecer asma, lo que no siempre se confi rma cuando se compara la obesidad con la hiperreactividad bronquial (HRB) en pacientes con síntomas de asma. Objetivo: Determinar si la obesidad se asocia con el diagnóstico de asma, confi rmado por presencia de síntomas e HRB a metacolina. Pacientes y Métodos: Se realizó un estudio transversal en población adulta del Área Norte de Madrid entre 2003 y 2007. Se incluyeron sujetos que habían padecido síntomas de asma en el último año, con un FEV1/FVC>70% y que precisaban una prueba de metacolina para confi rmar el diagnóstico. La obesidad se defi nió según el índice de masa corporal (IMC). Se aplicó un modelo de regresión logística para calcular odd ratios (OR) ajustadas. Resultados: Se estudiaron 1.424 sujetos y se diagnosticaron de asma 251 sujetos (17,6%) que, comparados con los 1.173 no diagnosticados de asma, eran más jóvenes y presentaban un IMC y parámetros de función pulmonar (FEV1, FEV1/FVC) más bajos (p<0,001). Tras ajustar el modelo por edad, sexo, FEV1 basal y FEV1/FVC el diagnóstico de asma no fue más prevalente en los sujetos obesos o con sobrepeso que en los sujetos con peso normal (OR 0,848, IC95% 0,59-1,20 y OR 0,616, IC95% 0,38-0,99, respectivamente). El diagnóstico de asma fue más frecuente en hombres obesos que en mujeres obesas (p=0,041). Conclusiones: La obesidad y el sobrepeso no se asociaron con el diagnóstico de asma establecido por la presencia de síntomas e HRB a metacolinaThis research project was carried out with a grant from Fundación para la Investigación Biomédica del Hospital Universitario La Paz (FIBHULP

    Olean (1, 7-dioxaspiro[5.5]undecane): A novel intraspecific chemical cue in coraebus undatus (f.) (coleoptera: Buprestidae)

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    The main aim of this work was to identify semiochemicals from the jewel beetle Coraebus undatus (F.) (Coleoptera: Buprestidae) that may aid in the improvement of current monitoring tools. First, HS-SPME collections revealed that individually sampled adults (>7 days old) of both sexes release the spiroacetal 1, 7-dioxaspiro[5.5]undecane (olean). Electroantennographic recordings from both sexes exposed to increasing amounts of olean followed a dose-dependent pattern, with females being more responsive than males to the highest amount of the compound (100 µg). In double-choice assays, adults older than seven days were significantly attracted to olean, whereas this attraction was not detected in insects aged less than seven days. Indeed, a repellent effect was observed in young females. Subsequent field trials employing sticky purple prism traps revealed that there were no differences among the number of insects caught in control and olean-baited traps at two different release rates (0.75 and 3.75 mg/day). Interestingly, all the trapped specimens were determined as mated females, regardless of the presence of olean. Overall, these findings provide a basis for unraveling the chemical ecology of the species, although further research is still needed to determine the specific role of this compound within the chemical communication of the species. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Amaru: plug&play resilient in-band control for SDN

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    Software-Defined Networking (SDN) is a pillar of next-generation networks. ImplementingSDN requires the establishment of a decoupled control communication, which might be installed either as anout-of-band or in-band network. While the benefits of in-band control networks seem apparent, no standardprotocol exists and most of setups are based on ad-hoc solutions. This article defines Amaru, a protocolthat provides plug&play resilient in-band control for SDN with low-complexity and high scalability. Amarufollows an exploration mechanism to find all possible paths between the controller and any node of thenetwork, which drastically reduces convergence time and exchanged messages, while increasing robustness.Routing is based on masked MAC addresses, which also simplifies routing tables, minimizing the numberof entries to one per path, independently of the network size. We evaluated Amaru with three differentimplementations and diverse types of networks and failures, and obtained excellent results, providing almoston-the-fly rerouting and low recovery time.Comunidad de MadridUniversidad de Alcal

    Depuration of the razor clams Ensis arcuatus (Jeffreys, 1865) and Ensis siliqua (L., 1758) (Solenacea)

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    The objective of this study is to evaluate a specific method for the depuration of the razor clams Ensis arcuatus (Jeffreys, 1865) and Ensis siliqua (L., 1758), aimed a obtaining an optimal quality in the depurated product. The presence of Salmonella spp. and levels of Escherichia coli and faecal coliforms were monitored before and during the process of depuration. These results show the importance not only of a previous selection of the damaged specimens, but also of banding the razor clams in groups of 20 specimens and placing them horizontally in cages. In all cases, less than 21 hours are needed in order to reach the legal levels required for human consumption.En este trabajo se evalúa un método de depuración para la navaja Ensis arcuatus (Jeffreys, 1865) y el longueirón Ensis siliqua (L., 1758) de fácil aplicación en las depuradoras comerciales y verificando que garantice una calidad óptima de los ejemplares al final del proceso. La presencia de Salmonella spp. y los niveles de Escherichia coli y de coliformes fecales son registrados antes y durante el proceso de depuración. Los resultados muestran la importancia de la selección previa de individuos no dañados y la eficacia de la colocación en posición horizontal de los especímenes en grupos de 20 individuos atados. En todos los casos se necesitaron menos de 21 h para alcanzar los niveles permitidos para el consumo humano.Instituto Español de Oceanografí
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