122 research outputs found

    Evolutionary Modeling to Evaluate the Shear Behavior of Circular Reinforced Concrete Columns

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    Despite their frequent occurrence in practice, only limited studies on the shear behavior of reinforced concrete (RC) circular members are available in the literature. Such studies are based on poor assumptions about the physical model, often resulting in being too conservative, as well as technical codes that essentially propose empirical conversion rules. On this topic in this paper, an evolutionary approach named EPR is used to create a structured polynomial model for predicting the shear strength of circular sections. The adopted technique is an evolutionary data mining methodology that generates a transparent and structured representation of the behavior of a system directly from experimental data. In this study experimental data of 61 RC circular columns, as reported in the technical literature, are used to develop the EPR models. As final result, physically consistent shear strength models for circular columns are obtained, to be used in different design situations. The proposed formulations are compared with models available from building codes and literature expressions, showing that EPR technique is capable of capturing and predicting the shear behavior of RC circular elements with very high accuracy. A parametric study is also carried out to evaluate the physical consistency of the proposed models

    On the Preliminary Structural Design Strategy of the Wing of the Next-Generation Civil Tiltrotor Technology Demonstrator

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    The T-WING project is a Clean Sky 2 research project aimed at designing, manufacturing, qualifying and flight-testing the new wing of the Next-Generation Civil Tiltrotor Technology Demonstrator (NGCTR-TD), as part of the Fast Rotorcraft Innovative Aircraft Demonstrator Platforms (FRC IADP) activities. Requirements, design strategy, methodology and main steps followed to achieve the composite wing preliminary design are presented. The main driving requirements have been expressed in terms of dynamic requirements (e.g., limitations on natural frequencies), aeroelastic requirements, i.e., compliance with European Aviation Safety Agency (EASA) CS-25 and CS-29 Airworthiness Requirements), structural requirements (e.g., target wing structural mass), functional requirements (e.g., fuel tanks, accessibility, assembly and integration, etc.) and wing preliminary loads. Based on the above-mentioned requirements, the first design loop is performed by targeting an optimal wing structure able to withstand preliminary design loads, and simultaneously with stiffness and inertia distributions leading to a configuration free from flutter within the flight envelope. The outcome from the first design loop is then used to refine the model and compute more reliable flight loads and repeat aeroelastic analysis, returning further requirements to be fulfilled in terms of wing stiffness and inertia distributions. The process is iterated till the fulfillment of all the project requirements

    Structural health monitoring of in-service tunnels

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    This work presents an overview of some of the most promising technologies for the structural health monitoring (SHM) of in-service tunnels. The common goal of damage or unusual behaviour detection is best pursued by an integrated approach based on the concurrent deployment of multiple technologies. Typically, traditional SHM systems are installed in problematic or special areas of the tunnels, giving information on conditions and helping manage maintenance. However, these methodologies often have the drawbacks of forcing the interruption of traffic for SHM system installation and monitoring only selected portions. Alternative solutions that would make it possible to keep the tunnel in normal operation and/or to analyse the entire infrastructure development through successive and continuous scanning stages, would be beneficial. In this paper, the authors will briefly review some traditional monitoring technologies for tunnels. Furthermore, the work is aimed at identifying alternative solutions, limiting or avoiding traffic interruptions

    Fatores associados ao near miss neonatal no Brasil

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    OBJECTIVE: This study evaluates the association between sociodemographic factors, maternal characteristics, organization of health services and neonatal near miss in public and private maternity hospitals in Brazil. METHODS: This is a prospective cohort of live births from the Nascer no Brasil survey, carried out between 2011 and 2012. Variables were established from the literature and organized on three levels: distal, intermediate, and proximal. The assessment was performed based on results of the bivariate analyzes and their respective p-values, with a significance level <0.20, using the Wald test. For multivariate analysis, the variables contained at the distal level were inserted, preserved in the model when significant (p < 0.05). This was also done when adjusting the intermediate and proximal levels. RESULTS: At the distal level, no variable was significantly associated with the outcome. At the intermediate level, mother’s age greater than or equal to 35 years (relative risk – RR = 1.32; 95%CI 1.04–1.66), cesarean delivery (RR = 1.34; 95%CI 1.07–1.67), smoking (RR = 1.48; 95%CI 1.04–2.10), gestational hypertensive syndrome (RR = 2.29; 95%CI 1.98–3.14), pre-gestational diabetes (RR = 2.63; 95%CI 1.36–5.05) and twin pregnancy (RR = 2.98; 95%CI 1.90–4.68) were variables associated with the outcome. At the proximal level, inadequate prenatal care (RR = 1.71; 95%CI 1.36–2.16) and the hospital/maternity being located in a capital city (RR = 1.89; 95%CI 1.40–2.55) were associated with neonatal near miss. CONCLUSIONS: The results show that neonatal near miss was influenced by variables related to the organization of health services and by maternal characteristics.OBJETIVO: Este estudo avalia a associação entre fatores sociodemográficos, características maternas, organização dos serviços de saúde e near miss neonatal em maternidades públicas e privadas do Brasil. MÉTODOS: Trata-se de uma coorte prospectiva de nascidos vivos da pesquisa Nascer no Brasil, realizada entre 2011 e 2012. As variáveis foram estabelecidas a partir da literatura e organizadas em três níveis: distal, intermediário e proximal. A avaliação foi realizada a partir dos resultados das análises bivariadas e de seus respectivos valores-p, com nível de significância < 0,20, pelo teste de Wald. Para a análise multivariada, foram inseridas as variáveis contidas no nível distal, conservadas no modelo quando significativas (p < 0,05). O mesmo foi feito no ajuste dos níveis intermediário e proximal. RESULTADOS: No nível distal, nenhuma variável apresentou associação significativa com o desfecho. No nível intermediário, idade da mãe maior ou igual a 35 anos (risco relativo – RR = 1,32; IC95% 1,04–1,66), parto cesáreo (RR = 1,34; IC95% 1,07–1,67), uso de fumo (RR = 1,48; IC95% 1,04–2,10), síndrome hipertensiva gestacional (RR = 2,29; IC95% 1,98–3,14), diabetes pré-gestacional (RR = 2,63; IC95% 1,36–5,05) e gestação gemelar (RR = 2,98; IC95% 1,90–4,68) foram variáveis associadas ao desfecho. No nível proximal, o pré-natal não adequado (RR = 1,71; IC95% 1,36–2,16) e a localização do hospital/maternidade na capital (RR = 1,89; IC95% 1,40–2,55) foram associados ao near miss neonatal. CONCLUSÃO: Os resultados mostram que o near miss neonatal foi influenciado pelas variáveis da organização dos serviços de saúde e pelas características maternas

    Transanal hemorrhoidal dearterialization (THD) for hemorrhoidal disease: An Italian single-institution 5-year experience analysis and updated literature review

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    Background: Hemorrhoidal disease is a highly prevalent, chronic disorder that usually compromise patients' quality of life. Despite recent advances in pharmacologic and surgical therapeutic options, a clear treatment "gold standard" is lacking. Our aim is to analyze the outcomes following Transanal Hemorrhoidal Dearterialization (THD) procedure. MethodsPatients who failed conservative treatment and underwent THD Doppler between 2017 and 2021 were enrolled. Follow-up interviews (consisting of clinical examination, Visual Analog Scale for pain-VAS, Vaizey incontinence score, Hemorrhoid Severity Score) were administered 1 week, 2 weeks, 1 month and 6 months after surgery. ResultsForty-seven out of 75 patients were male, and the mean age was 50 (+/- 17.9) years. Hemorrhoids were classified as Goligher's degree II in 25 cases, III in 40 and IV, simple irreducible without ischemic changes, in 10. The mean operative time was 35 (28-60) minutes, and most procedures were performed with epidural anesthesia (80%). No intraoperative complications occurred, and 73 patients (97.3%) were discharged within post-operative day 1. Early post-operative pain and bleeding occurred in 37.3% and 8% of patients, respectively. No patients experienced anal incontinence and severe symptoms at 6 months after surgery. The overall success rate was 97.3%. ConclusionsTHD is safe and effective in hemorrhoidal disease at degree II if bleeding, III, and IV without ischemic changes, both as a first intervention and on recurrence. Physician and patient need to understand each other's expectations, weight the risks and benefits, and customize the treatment

    Wing structure of the next-generation civil tiltrotor: From concept to preliminary design

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    The main objective of this paper is to describe a methodology to be applied in the preliminary design of a tiltrotor wing based on previously developed conceptual design methods. The reference vehicle is the Next-Generation Civil Tiltrotor Technology Demonstrator (NGCTR-TD) developed by Leonardo Helicopters within the Clean Sky research program framework. In a previous work by the authors, based on the specific requirements (i.e., dynamics, strength, buckling, functional), the first iteration of design was aimed at finding a wing structure with a minimized structural weight but at the same time strong and stiff enough to comply with sizing loads and aeroelastic stability in the flight envelope. Now, the outcome from the first design loop is used to build a global Finite Element Model (FEM), to be used for a multi-objective optimization performed by using a commercial software environment. In other words, the design strategy, aimed at finding a first optimal solution in terms of the thickness of composite components, is based on a two-level optimization. The first-level optimization is performed with engineering models (non-FEA-based), and the second-level optimization, discussed in this paper, within an FEA environment. The latter is shown to provide satisfactory results in terms of overall wing weight, and a zonal optimization of the composite parts, which is the starting point of an engineered model and a detailed FEM (beyond the scope of the present work), which will also take into account manufacturing, assembly, installation, accessibility and maintenance constraints

    I Duque de Caxias, Brazil, Municipal Plan for Food and Nutrition Security (2017-2020): an assessment based on the public policy cycle

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    Introdução: O I Plano Municipal de Segurança Alimentar e Nutricional (PLAMSAN) é uma ferramenta de planejamento, gestão e implementação da Política de Segurança Alimentar e Nutricional. Em Duque de Caxias, RJ, o I PLAMSAN foi sancionado em 2016. Objetivo: Realizar avaliação do I PLAMSAN-DC (2017-2020), utilizando como procedimentos metodológicos uma aproximação do “Ciclo de Políticas Públicas”. Métodos: Estudo de avaliação usando elementos da ferramenta “ciclo de políticas públicas” com base nos seguintes procedimentos metodológicos: 1) Análise documental; 2) Revisão de literatura; 3) Avaliação do cumprimento das metas com base nas respostas advindas das Secretarias que compõem a Câmara Intersetorial de Segurança Alimentar e Nutricional. Resultados: Verificou-se que, dentre as 42 metas do Plano, 14,7% foram cumpridas, 34,1% foram parcialmente cumpridas, e 51,2% não foram cumpridas. Conclusões: Observou-se que ainda não há acentuado papel por parte do nível municipal para a concretude de inúmeras ações que necessitam de recursos financeiros. Além disso, verifica-se a necessidade de superação de entraves, sobretudo em relação ao alcance da intersetorialidade e fortalecimento das estruturas componentes do sistema de segurança alimentar e nutricional

    Colorectal Cancer with Peritoneal Metastases: The Impact of the Results of PROPHYLOCHIP, COLOPEC, and PRODIGE 7 Trials on Peritoneal Disease Management

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    HIPEC is a potentially useful locoregional treatment combined with cytoreduction in patients with peritoneal colorectal metastases. Despite being widely used in several cancer centers around the world, its role had never been investigated before the results of three important RCTs appeared on this topic. The PRODIGE 7 trial clarified the role of oxaliplatin-based HIPEC in patients treated with radical surgery. Conversely, the PROPHYLOCHIP and the COLOPEC were designed to chair the role of HIPEC in patients at high risk of developing peritoneal metastases. Although all three trials demonstrated the relative ineffectiveness of HIPEC for treating or preventing peritoneal metastases, these results are not sufficient to abandon this technique. In addition to some criticisms relating to the design of the trials and their statistical value, the oxaliplatin-based HIPEC was found to be ineffective in preventing or treating peritoneal colorectal metastases, especially in patients already treated with systemic platinum-based chemotherapy. Several studies are ongoing investigating further HIPEC drugs and regimens. The review deeply discussed all the aspects and relapses of this new evidence
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