Betunes modificados con azufre: aditivos estabilizadores

En el presente trabajo se estudia la influencia de aditivos encaminados a conseguir la estabilidad de dichos betunes modificados. Mediante medidas de viscosidad y penetración se ha comprobado que la presencia combinada de diciclopentadieno + aminas, favorece la interacción del azufre con el betún por formación de polisulfuros. Asimismo, se ha analizado la influencia de inhibidores de radicales libre

Thermal behaviour of bitumen modified by sulphur addition

The most frequent use of bitumen is as binder for pavement applications. The effect of sulphur addition on the properties of the bitumen has been extensively studied several decades ago. Recently, there is a renewed interest in researching the behaviour of sulphur-bitumen combination, because off 1.The future availability of bitumen may be limited and 2. The beneficial consumption of great amounts of sulphur compounds from petroleum refining is advisable. The addition of sulphur to bitumen provokes the beginning of chemical reactions depending on the sulphur content and heating temperature. At heating temperatures T< 140 ºC liquid sulphur reacts with naphthenic-aromatic fraction forming polysulphides. At temperatures above 150 ºC dehydrogenization reactions with emission of hydrogen sulfide take place and naphthenic-aromatic molecules are transformed into asphaltenes. Therefore, the addition of sulphur to bitumen provokes changes in the chemical structure of the bitumen. The objective of this work is to analyze, the thermal behaviour of sulphur-bitumen mixtures of different composition (0-35 %wt sulphur content) prepared at 130 and 140 ºC, by means of differential scanning calorimetry (DSC). Besides, the volatile emissions of the mixtures at high temperature have been estimated from loss weight measurements as a function of stored tim

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Adhesives Based on Poly(glycidyl methacrylate‐co‐butyl acrylate) with Controlled Structure: Curing Behavior and Adhesion Properties on Metal Substrates

Abstract The adhesion properties of poly(glycidyl methacrylate (GMA)‐co‐butyl acrylate (BA)) statistical copolymers, synthesized by atom transfer radical polymerization (ATRP), are investigated employing three different curing agents or hardeners, such as diethanolamine (DEA), dicyandiamide (DICY), and 2‐cyanoacetamide (2‐CA) on copper, iron, brass, aluminum, and titanium metal surfaces. This work describes the treatment of the different surfaces, establishes the optimal curing conditions from differential scanning calorimetry (DSC) analysis of these novel adhesive systems, and evaluates the results of the single‐lap shear test for metal joints. Thus, by dynamic DSC measurements of the mixtures, a low curing temperature of 90 °C is defined when DEA is used as a curative; while systems based on DICY and 2‐CA require temperatures of 150 °C and 160 °C, respectively. In addition, the curing process of this controlled acrylic copolymer with DICY exhibits a singular behavior, possibly due to the curing reaction mechanism, where multiple epoxy‐amine ring‐opening polyaddition reactions take place between DICY's active hydrogens and epoxy groups of poly(GMA‐co‐BA). This latter curing system shows the highest adhesion features with lap‐shear strength at room temperature of 15.5 MPa, using copper as metallic substrate; however, the best results are obtained using 2‐CA as curing agent with aluminum and iron

An Overview of Earned Value Management in Airspace Industry

Earned value management (EVM) is an effective project management ap- proach. This method is used to manage project of different sectors and has been re- vised to improve its schedule estimates, the Earned Schedule Management and the Earned Duration Management and to include new components as quality, the quality earned value management. This paper explores the EVM methodology and proposes a model to manage projects aerospace engineers based in a real case study. The in- puts in the model are the planning and the monitoring of the case study, planned value, earned value and actual cost of aerospace projects

Smart photoluminescent nanohybrids based on CdSe quantum dots capped with multidentate thiolated pH-responsive and thermoresponsive polymers for nanosensing

Well-defined thermoresponsive polymers obtained by the atom transfer radical polymerization (ATRP) of short oligo(ethylene glycol) methyl ether methacrylates (MEOnMA, n¿=¿2, 3, or 8) with small ratios of a thiolated comonomer, 2-(acetylthio)ethylmethacrytale, can replace the hydrophobic trioctylphosphine oxide (TOPO) capping of CdSe quantum dots (QDs). After this facile ligand exchange, the mild hydrolysis of the acetylthiol group into thiol is the key to enhance the QD luminescence. However, the length of the ethylene glycol side chain is critical for the success of the functionalization; it is established that the shortest MEO2MA-based copolymers result in a compact coating and a highest quantum yield (up to a factor of 6) when compared with that of CdSe@TOPO in dichloromethane. In addition, the amphiphilic character of the copolymer allows the CdSe@P(MEOnMA-co-SEMA) nanohybrids to disperse in water. On the other hand, the residual ionizable thiol groups do not get attached to the QD surface, cause that the lower critical solubility temperature of the polymer depends on pH as well. Thus, at acidic pH, an abrupt increase in the luminescence emission accompanies the polymer collapse, which establishes the promise of these hybrids as temperature/pH nanosensors and targeted drug deliveryPeer Reviewe

Aula de innovación educativa

El artículo forma parte del monográfico de la revista: La metodología ABPPartiendo de la dinámica de trabajo del ABP se toma como punto de partida la creación y edición de un blog para que, además de constituir un proyecto en sí mismo, sirva de cuaderno de clase donde recoger y publicar el resto de proyectos: elaboración de un cómic, elaboración de un mapa conceptual y una línea de tiempo y, elaboración de un reportaje sobre una película que refleje un hecho o tema histórico.CataluñaConsejería de Educación, Formación y Empleo. Servicio de Publicaciones y Estadística; Avda. de la Fama, 15 - 1ª planta; 30006 Murcia; Tel. +34968279685; Fax +34968279835; [email protected]

Dinamización de las prácticas de la asignatura de Química mediante la aplicación de metodologías de aprendizaje activo

Este proyecto de innovación educativa se enmarca dentro de la asignatura de Química del primer curso del Grado en Óptica y Optometría de la UCM y tiene como objetivo la revisión y adaptación de las prácticas actuales de la asignatura al aprendizaje activo, fomentando la implicación de los alumnos para captar su atención y mejorar su aprendizaje. En concreto, se han utilizado técnicas de aula invertida y aprendizaje cooperativo incluyendo, además, la implementación de la herramienta WooclapSección Deptal. de Química Orgánica (Óptica y Optometría)Fac. de Óptica y OptometríaFALSEsubmitte

Tu salud la cuidas tú, y nosotros te ayudamos

El trabajo obtuvo el primer premio de la modalidad B: 'Una escuela más cooperativa y equitativa', de los Premios Joaquín Sama 2007. Se recogen páginas web de interés sobre la temática del trabajoSe describen un conjunto de actividades desarrolladas en el IES Siberia Extremeña (Talarrubias, Badajoz) para concienciar a los alumnos y a la comunidad educativa sobre los efectos nocivos del tabaco, el alcohol y otras drogas.ExtremaduraConsejería de Educación. Dirección General de Política Educativa; Calle Delgado Valencia, 6; 06800 Mérida (Badajoz); Tel. +34924006714; Fax +34924006716; [email protected]

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p &lt; 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures