Performance of fibre-reinforced refractory concrete

Steel fibres are commonly used in the refractory industry to reinforce high temperature concretes, though limited information is available on the mechanical properties of steel fibre refractories. This research has examined the influence of fibre geometry, fibre alloy composition and fibre content of stainless steel melt extract fibres on the performance of a proprietary 1400°C medium duty calcium aluminate-bonded castable. It has also examined whether it is necessary to obtain flexural and toughness measurements at temperature in order to properly evaluate the performance of fibre reinforcement or whether it is possible to obtain meaningful results from a much simpler room temperature test. [Continues.

Modelling and Stability Analysis of Brushless Doubly Fed Generators

The brushless doubly-fed machine (BDFM) continues to attract increasing interest for applications in wind generation where, robustness and low servicing costs are its principles advantages. The construction aspect of the BDFM has been widely studied and currently this machine can be build with good performances. However, the control aspect remains difficult to achieve and some studies show that the BDFM is less stable than the doubly-fed induction machine. To explore the BDFM stability in all operating mode, this paper proposes a stability analysis of a grid-connected variable speed wind turbine-based BDFM. For this purpose, a linearized small signals mathematical model is proposed which takes into account both grid and control disturbances. Then, the effect of electrical parameters variation and operating speed change on the stability of the BDFM has been studied. The stability has been investigated through simulation implementation. The obtained results demonstrate the validity and the superiority of the proposed model

Physical and mechanical behaviour of a roller compacted concrete reinforced with polypropylene fiber

In order to study the behaviour of a roller compacted concrete (RCC) reinforced with polypropylene fiber, six types of RCC were made with different content of fibers (0, 0.5, 1, 1.5, 2 and 2.5 Kg/m3). The physical parameters are the density, the workability, the shrinkage and the water absorption. For the mechanical parameters; the performances such as the compressive strength and the tensile strength (3 point bending and splitting) has been studied. The results show that the RCC reinforced with fibers present the better performances in terms of strength and physical behaviour. The results obtained show the positive effect of the polypropylene fiber addition on the mechanical strength, which increases about 23% for the mixture with 1 Kg/m3. For the physical properties, there is a decrease in the density and workability and an improvement in the water absorption proportional with the addition of polypropylene fiber. In addition, we conclude the positive effect of polypropylene fiber on the kinetics and development of the shrinkage. In this study, the best physical and mechanical performance was being observed in the mixture with 1 Kg/m3 of polypropylene.Keywords: Roller compacted concrete, polypropylene fiber, workability, mechanical strength, shrinkag

Vers un prototype de traduction automatique contrôlée français/arabe appliquée aux domaines à sécurité critique

The result of our research is a proposal for a controlled French to Arabic machine translation model, applied to security critical domains. This cross-disciplinary research study covers controlled languages and French to Arabic machine translation, two intimately related concepts. In a situation of crisis where communication must play its full role, and in the context of increasing globalisation where many languages coexist, our research findings show that the combination of these two concepts is sorely needed. No one can deny today the predominant role played by security in people’s daily life and the significant challenges it presents in modern societies. These more and more complex and interconnected societies present evident vulnerabilities that force them to rethink their means of protection and in particular that of their communication systems. Language communication with computerised systems is one of the most widely used forms of communication for the transfer of knowledge required in carrying out and completing tasks and in the good conduct of various activities. However, and contrary to an entrenched idea that tends to associate the risk of poor communication only with oral transmission, the use of written language can also be subject to risk. Indeed, a protocol or an alert which is badly formulated can provoke serious accidents due to misunderstanding, in particular during a crisis and under stress. It is in this context that our research has been undertaken. Our thesis proposes an innovative approach in the fields of controlled language and machine translation in which, relying on a microsystemic analysis of the language and a study of the corpus in intension, precise standards are defined for writing and translating protocols and security alerts written in French automatically into Arabic. Indeed, new concepts are introduced by means of several normative methods involved not only in the controlling process but also in the machine translation process. The French to Arabic machine translation system TACCT (Traduction Automatique Contrôlée Centre Tesnière) developed during our research is a rule-based system based on an isomorphic syntactic and semantic model stemming from intra- and interlanguage analysis between French and Arabic. It introduces new concepts including controlled mirror macrostructures, where the syntax and semantics of the source and target languages are represented at the same level.La présente recherche propose un modèle de traduction automatique français-arabe contrôlée appliquée aux domaines à sécurité critique. C’est une recherche transverse qui traite à la fois des langues contrôlées et de la traduction automatique français-arabe, deux concepts intimement liés. Dans une situation de crise où la communication doit jouer pleinement son rôle, et dans une mondialisation croissante où plusieurs langues cohabitent, notre recherche montre que l’association de ces deux concepts est plus que nécessaire. Nul ne peut contester aujourd’hui la place prépondérante qu’occupe la sécurité dans le quotidien des personnes et les enjeux qu’elle représente au sein des sociétés modernes. Ces sociétés davantage complexes et interconnectées manifestent une vulnérabilité flagrante qui les oblige à repenser leurs moyens d’organisation et de protection dont les systèmes de communication. La communication langagière à l’aide de systèmes informatisés est l’une des formes de communication la plus souvent utilisée pour le transfert des connaissances nécessaires à l’accomplissement des tâches et le déroulement des diverses actions. Toutefois, et contrairement à une idée bien ancrée qui tend à associer les risques d’une mauvaise communication à l’oral uniquement, l’usage de la langue écrite peut lui aussi comporter des risques. En effet des messages mal écrits peuvent conduire à de réelles catastrophes et à des conséquences irréversibles notamment dans des domaines jugés sensibles tels que les domaines à sécurité critique. C’est dans ce contexte que s’inscrit notre recherche. Cette thèse est une approche novatrice dans les domaines des langues contrôlées et de la traduction automatique. Elle définit avec précision, en s’appuyant sur une analyse microsystémique de la langue et un travail en intension sur le corpus, des normes pour la rédaction de protocoles de sécurité et d’alertes ainsi que leur traduction automatique vers l’arabe. Elle apporte en effet des notions nouvelles à travers plusieurs procédés normatifs intervenant non seulement dans le processus de contrôle mais également dans le processus de traduction. Le système de traduction automatique français-arabe TACCT (Traduction Automatique Contrôlée Centre Tesnière) mis au point dans cette thèse est un système à base de règles linguistiques qui repose sur un modèle syntaxico-sémantique isomorphique issu des analyses intra- et interlangues entre le français et l’arabe. Il introduit de nouveaux concepts notamment celui des macrostructures miroir contrôlées, où la syntaxe et la sémantique des langues source et cible sont représentées au même niveau

Factores de riesgo, complicaciones y evaluación del manejo de los pacientes con trombosis venosa superficial de miembros inferiores atendidos en servicios de urgencias españoles

Objectives: Three main objectives were evaluated: To describe the characteristics of patients diagnosed with isolated superficial venous thrombosis (SVT) of the lower limbs in hospital emergency departments (ED), and to evaluate adherence to clinical practice guidelines (first objective) in diagnostic (performance of venous ultrasound) and therapeutic management (initiation of anticoagulant therapy). To describe the therapeutic management of patients with isolated SVT of the lower limbs in the ED (second objective) and to evaluate the impact of the treatment established in the ED on the evolution (third objective), in terms of complications of venous thromboembolic disease (VTE), and to know the characteristics of the patients who suffer complications. Method: To respond to the first objective, a retrospective cohort study was conducted in 18 EDs. All patients seen in EDs with a final diagnosis of TVS in MMII, aged ≥18 years, from January 2016 to May 2017 were included. To assess non-adherence to clinical practice guideline recommendations, a backward stepwise multiple logistic regression model was fitted. To answer the second and third main objective, patients with an objective diagnosis of isolated SVT were selected. VTE complications [deep vein thrombosis (DVT), pulmonary thromboembolism (PE) and extension or recurrence of SVT)], clinically relevant bleeding and death at 180 days were collected. Variables associated with complications were assessed using Cox regression. Results: To meet the objectives of the study, two main sections were classified: a total patients (first main objective) and a subgroup of patients with an objective diagnosis of SVT (second and third main objectives). Regarding the total patients, 1166 patients were included. The mean age was 59.6 years, 67.9% were women. Twenty-four.4% had a history of VTE. 8.9% had some complication at 180 days. There were 17 patients (1.5%) with hemorrhage and 16 (1.4%) deaths. Venous ultrasound was performed in 703 (60.3%) patients. A total of 898 (77%) received anticoagulation treatment, with a median of 27.3 days. The variables associated with the decision to anticoagulate were: history of VTE (OR 1.60; 95% CI: 1.12-2.30), vari¬ces (OR 1.40; 95% CI: 1.12-2.30), limb pain (OR 1.44; 95% CI: 1.08-191), painful cord (OR 1.30; 95% CI: 0.97-1.73) and performance of venous ultrasound (OR 1.60; 95% CI: 1.94-3.45). As for the subgroup of patients with an objective diagnosis of SVT, 703 patients were included. A total of 84.1% received anticoagulation for 30 days (interquartile range 15-42), 81.3% with low-molecular-weight heparin (48% prophylactic doses, 52% intermediate-therapeutic). In 180 days, 64 patients (9.1%) had VTE complications, 12 (1.7%) had clinically relevant bleeding, and 4 died (0.6%). Patients in whom anticoagulation was instituted in the ED took longer to develop complications (66 vs. 11 days, p = 0.009). Of those who developed complications, 76.6% were not anticoagulated at the time. Previous VTE was independently associated with the development of complications (adjusted hazard ratio 2.20; 95% confidence interval: 1.34-3.62). Conclusions: Adherence to clinical practice guidelines for the diagnosis and treatment of isolated lower-limb SVT is low in Spanish emergency departments. Ultrasound imaging is not ordered for 1 out of every 2 to 3 patients, and anticoagulant treatment is not started in 1 out of 4 patients. There is great room for improvement. ED treatment of SVT varies and is often suboptimal. The incidence of thromboembolic complications after SVT is high. Starting anticoagulation in the ED delays the development of complications. Patients with a history of thromboembolic disease are more at risk of complications.Objetivo: Se evaluaron tres objetivos principales: Describir las características de los pacientes diagnosticados de trombosis venosa superficial (TVS) aislada de miembros inferiores (MMII) en servicios de urgencias hospitalarios (SUH), y evaluar la adherencia a las guías de práctica clíni¬ca (primer objetivo) en el manejo diagnóstico (realización de ecografía venosa) y terapéutico (instauración de tratamiento anticoagulante). Describir el manejo terapéutico de los pacientes con TVS aislada de MMII en SUH (segundo objetivo) y evaluar el impacto del tratamiento instaurado en urgencias en la evolución (tercer objetivo), en términos de complicaciones de enfermedad tromboembólica venosa (ETV), y conocer las características de los pacientes que sufren complicaciones. Método: Para responder al primer objetivo se realizó un estudio de cohortes retrospectivo en 18 SUH. Se incluyeron todos los pacientes atendidos en los SUH con diagnóstico final de TVS en MMII, con edad ≥18 años, de enero de 2016 a mayo de 2017. Para evaluar la no adherencia a las recomendaciones de las guías de práctica clínica se ajustó un modelo de regresión logística múltiple por pasos hacia atrás. Para responder al segundo y tercer objetivo principal, se seleccionaron a los pacientes con diagnóstico objetivo de TVS aislada. Se recogieron las complicaciones de ETV [trombosis venosa profunda (TVP), tromboembolia pulmonar (TEP) y extensión o recurrencia de TVS)], sangrados clínicamente relevantes y defunciones a 180 días. Se evaluaron las variables asociadas a las complicaciones mediante una regresión de Cox. Resultados: Para responder a los objetivos del estudio, se clasificaron dos grandes apartados: una muestra general de pacientes (primer objetivo principal) y un subgrupo de pacientes con diagnóstico objetivo de TVS (segundo y tercer objetivo principal). En cuanto a la muestra general, 1166 pacientes fueron incluidos. La edad media fue de 59,6 años, el 67,9% eran mu¬jeres. El 24,4% tenían antecedentes de ETV. El 8,9% tuvieron alguna complica¬ción a 180 días. Hubo 17 pacientes (1,5%) con hemorragia y 16 (1,4%) muertes. Se realizó ecografía venosa a 703 (60,3%) pacientes. Recibieron tratamiento anticoagulante 898 (77%), con una mediana de 27,3 días. Las variables asociadas con la decisión de anticoagular fueron: antecedentes ETV (OR 1,60;IC 95%: 1,12-2,30), vari¬ces (OR 1,40;IC 95%:1,12-2,30), dolor extremidad (OR1,44; IC 95%: 1,08-191), cordón doloro¬so (OR 1,30;IC 95%:0,97-1,73) y realización de ecografía venosa (OR 1,60;IC 95%: 1,94-3,45). En cuanto al subgrupo de pacientes con diagnóstico objetivo de TVS, se incluyeron 703 pacientes. El 84,1% recibieron anticoagulación durante 30 días (rango intercuartil 15-42), 81,3% con heparina de bajo peso molecular (48% dosis profilácticas, 52% intermedias-terapéuticas). En 180 días, 64 pacientes (9,1%) tuvieron complicación de ETV, 12 (1,7%) tuvieron sangrado clínicamente relevante, y 4 fallecieron (0,6%). Los pacientes en que se instauró anticoagulación en urgencias tardaron más tiempo en desarrollar complicaciones (66 vs 11 días, p = 0,009). El 76,6% de los que se complicaron no estaban anticoagulados en ese momento. La ETV previa se asoció de forma independiente con el desarrollo de complicaciones (hazard ratio ajustada 2,20; intervalo de confianza del 95%:1,34-3,62). Conclusión: Existe una baja adherencia a las recomendaciones de las guías de práctica clínica en el manejo diagnósti¬co y terapéutico de los pacientes con diagnóstico de TVS aislada de MMII en los SUH españoles: no se realiza ecografía venosa en uno de cada 2-3 pacientes, y no se instaura tratamiento anticoagulante en 1 de cada 4. Esto constituye un margen de mejora muy relevante. El tratamiento en urgencias de la TVS aislada es heterogéneo y con frecuencia subóptimo. La incidencia de complicaciones de ETV es elevada. El tratamiento anticoagulante iniciado en urgencias supone un retraso en el desarrollo de complicaciones. Los pacientes con ETV previa tienen más riesgo de complicaciones.Escuela de DoctoradoDoctorado en Investigación en Ciencias de la Salu

Innovations in Radiotherapy Technology.

Many low- and middle-income countries, together with remote and low socioeconomic populations within high-income countries, lack the resources and services to deal with cancer. The challenges in upgrading or introducing the necessary services are enormous, from screening and diagnosis to radiotherapy planning/treatment and quality assurance. There are severe shortages not only in equipment, but also in the capacity to train, recruit and retain staff as well as in their ongoing professional development via effective international peer-review and collaboration. Here we describe some examples of emerging technology innovations based on real-time software and cloud-based capabilities that have the potential to redress some of these areas. These include: (i) automatic treatment planning to reduce physics staffing shortages, (ii) real-time image-guided adaptive radiotherapy technologies, (iii) fixed-beam radiotherapy treatment units that use patient (rather than gantry) rotation to reduce infrastructure costs and staff-to-patient ratios, (iv) cloud-based infrastructure programmes to facilitate international collaboration and quality assurance and (v) high dose rate mobile cobalt brachytherapy techniques for intraoperative radiotherapy