Shear behavior of large and shallow fiber reinforced concrete beams

Steel fibers are very important in beams under shear loading, as evidenced from several scientific papers reported into the last decade journals. This paper reports some recent results of an experi-mental campaign on FRC beams under shear loading tested at the University of Brescia, focusing on the size effect issue and the shear behavior of shallow beams. With the first regard, nine full scale beams, having a height varying from 500 to 1500 mm, were tested to analyze steel fibers influence on size effect. Concerning the shallow beams, eight beams (all having depth of 250 mm) with two different widths, fiber content were tested for evaluating the shear response of typical structural members utilized in Southern Europe in residential buildings. Results show that a relatively low volume fraction of fibers can significantly increase shear bearing capacity and ductility. The size effect issue is substantially limited and it is observed that, with a fairly tough FRC composite, it is possible to completely eliminate this detrimental effect. Shallow beams do not show the typical brittle failure also without any shear reinforcement and the effect of fibers is even more prominent than in deep beams

Parametric Frequency Conversion of Short Optical Pulses Controlled by a CW Background

We predict that parametric sum-frequency generation of an ultra-short pulse may result from the mixing of an ultra-short optical pulse with a quasi-continuous wave control. We analytically show that the intensity, time duration and group velocity of the generated idler pulse may be controlled in a stable manner by adjusting the intensity level of the background pump

A Hyper-Solution Framework for SVM Classification: Application for Predicting Destabilizations in Chronic Heart Failure Patients

Support Vector Machines (SVMs) represent a powerful learning paradigm able to provide accurate and reliable decision functions in several application fields. In particular, they are really attractive for application in medical domain, where often a lack of knowledge exists. Kernel trick, on which SVMs are based, allows to map non-linearly separable data into potentially linearly separable one, according to the kernel function and its internal parameters value. During recent years non-parametric approaches have also been proposed for learning the most appropriate kernel, such as linear combination of basic kernels. Thus, SVMs classifiers may have several parameters to be tuned and their optimal values are usually difficult to be identified a-priori. Furthermore, combining different classifiers may reduce risk to perform errors on new unseen data. For such reasons, we present an hyper-solution framework for SVM classification, based on meta-heuristics, that searches for the most reliable hyper-classifier (SVM with a basic kernel, SVM with a combination of kernel, and ensemble of SVMs), and for its optimal configuration. We have applied the proposed framework on a critical and quite complex issue for the management of Chronic Heart Failure patient: the early detection of decompensation conditions. In fact, predicting new destabilizations in advance may reduce the burden of heart failure on the healthcare systems while improving quality of life of affected patients. Promising reliability has been obtained on 10-fold cross validation, proving our approach to be efficient and effective for an high-level analysis of clinical data

Molecular Taxonomy: Use of Transcriptional Profiles to Identify Different ALS Subtypes

Advances in diagnostic techniques and high-throughput biotechnologies provide a compelling opportunity to improve the diagnosis and treatment of diseases by developing a “New Taxonomy” that defines diseases on the basis of their underlying molecular and environmental factors rather than on traditional physical signs and symptoms. Oncology represents the first interesting example of how genomic medicine has changed the understanding of diseases and their therapy. However, much work remains to be completed on the molecular characterization and classification of complex and multifactorial diseases, including neurodegenerative disorders. Our research group has recently shown the genomic heterogeneity of sporadic amyotrophic lateral sclerosis (SALS), identifying two divergent subtypes associated with differentially expressed genes and pathways and providing several potential biomarkers and therapeutic targets. This chapter reviews the results emerged from our work, highlighting how molecular characterization of SALS patients may provide a framework for developing a more precise and accurate classification of diseases that could revolutionize the diagnosis, therapy, and clinical decisions of diseases, leading to more individualized treatments and improved outcomes for patients

Stable Control of Pulse Speed in Parametric Three-Wave Solitons

We analyze the control of the propagation speed of three wave packets interacting in a medium with quadratic nonlinearity and dispersion. We found analytical expressions for mutually trapped pulses with a common velocity in the form of a three-parameter family of solutions of the three-wave resonant interaction. The stability of these novel parametric solitons is simply related to the value of their common group velocity

Estudio comparativo de la orientación del refuerzo en losas de hormigón autocompactante reforzado con fibras poliméricas y de acero

[ES] Entre los factores que afectan la orientación de las fibras en el hormigón autocompactante se destacan el efecto pared y la velocidad de flujo. Como consecuencia, se puede producir una respuesta anisotrópica en los elementos estructurales que depende de la forma de vertido y de la geometría de los mismos. Este trabajo analiza la orientación de las fibras y sus efectos sobre las propiedades mecánicas en losas rectangulares de 1800 mm de largo, 925 mm de ancho y 100 mm de altura moldeadas con hormigones autocompactantes reforzados con diferentes fibras de acero y macrofibras poliméricas, todos elaborados a partir de un mismo hormigón de base. De cada losa se aserraron 18 prismas de 550 mm de largo en direcciones normal y perpendicular a la dirección de vertido; luego se ensayaron a flexión siguiendo la norma EN 14651 y finalmente se realizó un conteo de la densidad de fibras en las superficies de fractura. Como referencia también se realizaron ensayos similares sobre probetas prismáticas de 150 x 100 x 600 mm y ensayos de compresión sobre cubos. Los resultados muestran el efecto del tipo de fibra y el grado de variabilidad que puede ocurrir en este tipo de elementos estructurales.Conforti, A.; Plizzari, G.; Zerbino, R. (2018). Estudio comparativo de la orientación del refuerzo en losas de hormigón autocompactante reforzado con fibras poliméricas y de acero. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 609-618. https://doi.org/10.4995/HAC2018.2018.5496OCS60961

High-performance fiber reinforced concrete coupling beams: from research to practice

Results from experimental research that led to the development of a new design of coupling beams constructed with High-Performance Fiber Reinforced Concrete (HPFRC) and simplified reinforcement detailing are presented, along with information related to its implementation in a high-rise building in the city of Seattle, WA. The experimental program consisted of the testing, under large displacement reversals, of a series of large-scale HPFRC coupling beams with span-toheight ratios ranging between 1.75 and 3.3. The main goal of the experimental program was to evaluate the possibility of simplifying diagonal and confinement reinforcement detailing without compromising seismic performance. Experimental results indicate that the use of HPFRC allows the complete elimination of diagonal reinforcement in beams with span-to-height ratios greater than or equal to approximately 2.2. Also, special confinement reinforcement, as used in regular reinforced concrete coupling beams, was found to only be required over a distance of half the beam height from each beam end. For beams with span-to-height ratios smaller than approximately 2.2, a 2/3 reduction in diagonal reinforcement was found to be possible, with the same relaxation in confinement reinforcement as for the more slender coupling beams. Drift capacities of the HPFRC coupling beam specimens, when subjected to shear reversals with amplitudes comparable to the upper shear limit allowed in the ACI Building Code, ranged between approximately 5% and 7% for span-to-height ratios of 1.75 and 3.3, respectively

El estado docente

La fuente utilizada para tomar la imagen digital es : ICC, Clásicos colombianos IV, M.A. Caro, Obras, Tomo I, 1962| la primera publicación del texto fue : Anales religiosos de Colombia, Bogotá, Año I, núm 11, 1° de abril

La controversia religiosa

La fuente utilizada para tomar la imagen digital es : Artículos y discursos, Biblioteca Popular de Cultura Colombiana, Bogotá, 1951| la primera publicación del texto fue : Biblioteca popular de Cultura Colombiana, 1951.Caro distingue la ciencia y la religión, la fe y la razón y los límites de éstas, pues, la verdad es mayor a la razón