Failure of steel tanks during their construction: experiments and computational modeling

La construcción de tanques de acero destinados al almacenamiento de petróleo plantea un estado de solicitaciones frente a la acción de viento que no está contemplado en las normativas. En la Patagonia Argentina, como en otros lugares reportados en la bibliografía, se han registrado casos de colapso de este tipo de estructuras durante la etapa constructiva a moderadas velocidades de viento. Estudios numéricos anteriores condujeron a determinar como factor desencadenante del mecanismo de colapso, la falta de integridad estructural por las irregularidades en la continuidad del apoyo en el sentido circunferencial. Un mayor conocimiento del comportamiento fluido-dinámico del viento permite ajustar las acciones actuantes usadas en el abordaje del estudio numérico. Este trabajo completa el análisis de tanques no anclados que colapsaron por acción del viento durante su etapa constructiva evaluando el patrón del flujo interior en los tanques mediante ensayos en túnel de viento, incluyendo estos resultados en el estudio numérico. La estructura se modela por elementos finitos mediante un código de propósitos generales, evaluando la inestabilidad del equilibrio mediante un análisis de bifurcación lineal (LBA) y análisis no lineal geométrico con imperfecciones (GNIA). Los ensayos permitieron determinar la formación de un vórtice interior que produce una depresión mayor que el de la estela a sotavento del tanque.During the construction of steel storage oil tanks, a state of stresses under wind loads is induced which is not covered by the regulations. Cases of collapse of such structures during their construction occurred in Patagonia Argentina and elsewhere under moderate wind speeds, as reported in the literature. Previous numerical studies concentrated on the identification of the collapse mechanism, which was related to the loss of structural integrity due to discontinuity of the support in the circumferential direction. An increased knowledge of the fluid dynamic behavior under wind allows obtaining an improved input used in the subsequent numerical study. This paper provides new insight into the wind behavior of unanchored tanks that collapsed during their construction by wind tunnel tests to evaluate the flow pattern inside the tanks, which is an input for the subsequent numerical study. The structure is modeled using a general purpose finite element code, in which instability is evaluated by Linear Bifurcation Analysis (LBA) and by Geometrically Nonlinear Analysis with Imperfections (GNIA). Tests allowed identifying that an inner vortex is induced which produces a greater depression than the downwind wake in the leeward region of the tank.Fil: Jaca, Rossana Claudia. Universidad Nacional del Comahue; ArgentinaFil: Cicerone, Esteban. Universidad Nacional del Comahue; ArgentinaFil: Hernandez, Facundo C.. Universidad Nacional del Comahue; ArgentinaFil: Lassig, Jorge Luis. Universidad Nacional del Comahue; ArgentinaFil: Godoy, Luis Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados En Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Instituto de Estudios Avanzados En Ingeniería y Tecnología; Argentin

Discrete-time MPC for switched systems with applications to biomedical problems

Switched systems in which the manipulated control action is the time-dependingswitching signal describe many engineering problems, mainly related to biomedical applications. In such a context, to control the system means to select an autonomous system - at each time step - among a given finite family. Even when this selection can be done by solving a Dynamic Programming (DP) problem, such a solution is often difficult to apply, and state/control constraints cannot be explicitly considered. In this work a new set-based Model Predictive Control (MPC) strategy is proposed to handle switched systems in a tractable form. The optimization problem at the core of the MPC formulation consists in an easy-to-solve mixed-integer optimization problem, whose solution is applied in a receding horizon way. Two biomedical applications are simulated to test the controller: (i) the drug schedule to attenuate the effect of viralmutation and drugs resistance on the viral load, and (ii) the drug schedule for Triple Negative breast cancer treatment. The numerical results suggest that the proposed strategy outperform the schedule for available treatments.Fil: Anderson, Alejandro Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: González, Alejandro Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Ferramosca, Antonio. Universidad Tecnológica Nacional; ArgentinaFil: Hernandez Vargas, Esteban Abelardo. Frankfurt Institute For Advanced Studies-fias; Alemani

Discrete-time switching MPC with applications to mitigate resistance in viral infections

Many engineering applications can be described as switched linear systems, in which the manipulated control action is the time-dependent switching signal. In such a case, the control strategy must select a linear autonomous system at each time step, among a finite number of them. Even when this selection can be done by solving a Dynamic Programming (DP) problem, the implementation of such a solution is often difficult and state/control constraints cannot be explicitly accounted for. In this paper, a new set-based Model Predictive Control (MPC) strategy is presented to handle switched linear systems in a tractable form. The optimization problem at the core of the MPC formulation consists of an easy-to-solve mixed-integer optimization problem, whose solution is applied in a receding horizon way. The medical application of viral mutation and its respective drug resistance is addressed to acute and chronic infections. The objective is to attenuate the effect of mutations on the total viral load, and the numerical results suggested that the proposed strategy outperforms the schedule for available treatments.Fil: Anderson, Alejandro Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: González, Alejandro Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Ferramosca, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Hernandez Vargas, Esteban Abelardo. Frankfurt Institute For Advanced Studies-fias; Alemani

Development of Efficient FPGA-Based Multi-Channel Phase Meters for IR-Interferometers

Infrared (IR) interferometry is a method for measuring the line-electron density of fusion plasmas. The significant performance achieved by FPGAs in solving digital signal processing tasks advocates the use of this type of technology in two-color IR interferometers of modern stellarators, such as the TJ-II (Madrid, Spain) and the future W7-X (Greifswald, Germany). In this work the implementation of a line-average electron density measuring system in an FPGA device is described. Several optimizations for multichannel systems are detailed and test results from the TJ-II as well as from a W7-X prototype are presented

Prevalence estimation of significant fibrosis because of NASH in Spain combining transient elastography and histology

Hepatic fibrosis; Non-alcoholic steatohepatitis; Transient elastographyFibrosis hepática; Esteatohepatitis no alcohólica; Elastografía transitoriaFibrosi hepàtica; Esteatohepatitis no alcohòlica; Elastografia transitòriaBackground & Aims Non-alcoholic fatty liver disease (NAFLD) has become a major public health problem, but the prevalence of fibrosis associated with non-alcoholic steatohepatitis (NASH) is largely unknown in the general population. This study aimed to provide an updated estimation of the prevalence of NASH fibrosis in Spain. Methods This was an observational, retrospective, cross-sectional, population-based study with merged data from two Spanish datasets: a large (N = 12 246) population-based cohort (ETHON), including transient elastography (TE) data, and a contemporary multi-centric biopsy-proven NASH cohort with paired TE data from tertiary centres (N = 501). Prevalence for each NASH fibrosis stage was estimated by crossing TE data from ETHON dataset with histology data from the biopsy-proven cohort. Results From the patients with valid TE in ETHON dataset (N = 11 440), 5.61% (95% confidence interval [95% CI]: 2.53-11.97) had a liver stiffness measurement (LSM) ≥ 8 kPa. The proportion attributable to NAFLD (using clinical variables and Controlled Attenuation Parameter) was 57.3% and thus, the estimated prevalence of population with LSM ≥ 8 kPa because of NAFLD was 3.21% (95% CI 1.13–8.75). In the biopsy-proven NASH cohort, 389 patients had LSM ≥ 8 kPa. Among these, 37% did not have significant fibrosis (F2-4). The estimated prevalence of NASH F2-3 and cirrhosis in Spain's adult population were 1.33% (95% CI 0.29–5.98) and 0.70% (95% CI 0.10–4.95) respectively. Conclusions These estimations provide an accurate picture of the current prevalence of NASH-related fibrosis in Spain and can serve as reference point for dimensioning the therapeutic efforts that will be required as NASH therapies become available

Digital Images Authentication Technique Based on DWT, DCT and Local Binary Patterns

In the last few years, the world has witnessed a ground-breaking growth in the use of digital images and their applications in the modern society. In addition, image editing applications have downplayed the modification of digital photos and this compromises the authenticity and veracity of a digital image. These applications allow for tampering the content of the image without leaving visible traces. In addition to this, the easiness of distributing information through the Internet has caused society to accept everything it sees as true without questioning its integrity. This paper proposes a digital image authentication technique that combines the analysis of local texture patterns with the discrete wavelet transform and the discrete cosine transform to extract features from each of the blocks of an image. Subsequently, it uses a vector support machine to create a model that allows verification of the authenticity of the image. Experiments were performed with falsified images from public databases widely used in the literature that demonstrate the efficiency of the proposed method

Continuous Phase Measurement in the W7-X Infrared Interferometer by Means of a FPGA and High-Speed ADCs.

Interferometry is used for measuring line average electronic densities in fusion plasmas. The W7-X stellarator will employ a two-color CO2 (10.591 m) and CO (5.295 m) heterodyne-infrared interferometer as an electronic density measurement diagnostic. The frequency displacement is 40 MHz for the CO2 wavelength and 25 MHz for the CO, so these values will fix the heterodyne frequencies. Because the frequency gap between the two carriers is wide enough and the detector sensitivity is similar for both wavelengths, it is possible to use a single detector for the two signals; nevertheless, they should be split with filters. Traditionally, the intermediate-frequency signals should be filtered, downconverted to a lower frequency by the use of analog circuitry, and then processed. A new approach is proposed. The intermediate-frequency signals are directly sampled by means of high-speed analog-to-digital converters followed by a digital diplexer and a specific phase-meter processor implemented in a field-programmable gate array. Preliminary results from the W7-X infrared interferometer prototype, without plasma, are presented

Intracellular delivery of biologically-active fungal metabolite gliotoxin using magnetic nanoparticles

Gliotoxin (GT), a secondary metabolite produced by Aspergillus molds, has been proposed as a potential anti-tumor agent. Here we have developed a nanoparticle approach to enhance delivery of GT in tumor cells and establish a basis for its potential use as therapeutical drug. GT bound to magnetic nanoparticles (MNPs) retained a high anti-tumor activity, correlating with efficient intracellular delivery, which was increased in the presence of glucose. Our results show that the attachment of GT to MNPs by covalent bonding enhances intracellular GT delivery without affecting its biological activity. This finding represents the first step to use this potent anti-tumor agent in the treatment of cancer

100 artigos que devem/podem ser lidos realmente por todos os ecólogos?

Reading scientific articles is fundamental for researchers, not only to keep pace with advances in their field, but also to know those giants on whose shoulders they are standing. In this sense, Courchamp and Bradshaw (2018) recently proposed a list of 100 seminal papers deemed to be of major importance in ecology, thus providing a general ‘must-read’ list for any new ecologist. The authors metaphorically speak of ecology as an ever-growing brick wall of published evidence. In order to quantify the degree of interference of the paywall over the wall of science, we took the opportunity given by the 100 seminal papers list and registered how many articles have been made universally and freely available by the publisher. Of the 100 scientific papers proposed as foundations of the wall of ecological knowledge, 66 are behind the paywall, with a total cost of US$1,560. This paywall exacerbates the existing asymmetries in ecological research between researchers from developed countries and the Global South. Diversity in research, as in ecological systems, is a source of robustness. Publishing high-quality articles in regional open peer-reviewed scientific journals is a suitable way to valorize Global South ecology, helping minimize the existing asymmetries.Keywords: ecology, information access, paywall, inequity.Ler artigos científicos é uma atividade fundamental para os pesquisadores, não só para acompanhar os desenvolvimentos em seu campo de ação, mas também para saber sobre os ombros de que gigantes estão de pé. Nesse sentido, Courchamp e Bradshaw (2018) propuseram recentemente uma lista de 100 artigos seminais, considerados de suma importância na ecologia, que constituem uma lista geral de artigos que os novos ecologistas “devem ler”. Os autores falam metaforicamente da ecologia como uma parede de evidência publicada em constante construção. A fim de quantificar o nível de interferência da parede de pagamento no muro da ciência, aproveitamos a oportunidade dada pela lista de 100 artigos seminais e registramos quantos artigos estão disponíveis gratuitamente por meio da entidade editorial. Dos 100 artigos científicos propostos como os fundamentos do muro do conhecimento ecológico, 66 estão por trás do muro de pagamento, com um custo total de US$ 1.560. Esse muro de pagamento exacerba as assimetrias existentes na pesquisa ecológica entre pesquisadores de países desenvolvidos e do sul global. A diversidade na pesquisa, como nos sistemas ecológicos, é uma fonte de robustez. A publicação de artigos de alta qualidade em periódicos regionais de livre acesso e revisados por pares é uma maneira viável de avaliar coletivamente a ecologia do sul global e ajudar a minimizar as assimetrias existentes.Palavras-chave: ecologia, acesso à informação, muro de pagamento, desigualdade