13,257 research outputs found
The compression chord capacity model for the shear design and assessment of reinforced and prestressed concrete beams
This is the accepted version of the following article: [Cladera, A., MarĂ, A., BairĂĄn, J. M., Ribas, C., Oller, E. and Duarte, N. (2016), The compression chord capacity model for the shear design and assessment of reinforced and prestressed concrete beams. Structural Concrete, 17: 1017â1032. doi:10.1002/suco.201500214], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/suco.201500214/fullA simplified mechanical model is presented for the shear strength prediction of reinforced and prestressed concrete members with and without transverse reinforcement, with I, T or rectangular cross-section. The model, derived with further simplifications from a previous one developed by the authors, incorporates the contributions of the concrete compression chord, the cracked web, the dowel action and the shear reinforcement in a compact formulation. The mechanical character of the model provides valuable information about the physics of the problem and incorporates the most relevant parameters governing the shear strength of structural concrete members. The predictions of the model fit very well the experimental results collected in the ACI-DAfStb databases of shear tests on slender reinforced and prestressed concrete beams with and without stirrups. Due to this fact and the simplicity of the derived equations it may become a very useful tool for structural design and assessment in engineering practice.Peer ReviewedPostprint (author's final draft
Chimpanzees demonstrate individual differences in social information use
Studies of transmission biases in social learning have greatly informed our understanding of how behaviour patterns may diffuse through animal populations, yet within-species inter-individual variation in social information use has received little attention and remains poorly understood. We have addressed this question by examining individual performances across multiple experiments with the same population of primates. We compiled a dataset spanning 16 social learning studies (26 experimental conditions) carried out at the same study site over a 12-year period, incorporating a total of 167 chimpanzees. We applied a binary scoring system to code each participantâs performance in each study according to whether they demonstrated evidence of using social information from conspecifics to solve the experimental task or not (Social Information ScoreââSISâ). Bayesian binomial mixed effects models were then used to estimate the extent to which individual differences influenced SIS, together with any effects of sex, rearing history, age, prior involvement in research and task type on SIS. An estimate of repeatability found that approximately half of the variance in SIS was accounted for by individual identity, indicating that individual differences play a critical role in the social learning behaviour of chimpanzees. According to the model that best fit the data, females were, depending on their rearing history, 15â24% more likely to use social information to solve experimental tasks than males. However, there was no strong evidence of an effect of age or research experience, and pedigree records indicated that SIS was not a strongly heritable trait. Our study offers a novel, transferable method for the study of individual differences in social learning
Optimización del diseño estructural de pavimentos asfålticos para calles y carreteras
grĂĄficos, tablasThe construction of asphalt pavements in streets and highways is an activity that requires optimizing the consumption of significant economic and natural resources. Pavement design optimization meets contradictory objectives according to the availability of resources and usersâ needs. This dissertation explores the application of metaheuristics to optimize the design of asphalt pavements using an incremental design based on the prediction of damage and vehicle operating costs (VOC). The costs are proportional to energy and resource consumption and polluting emissions. The evolution of asphalt pavement design and metaheuristic optimization techniques on this topic were reviewed. Four computer programs were developed: (1) UNLEA, a program for the structural analysis of multilayer systems. (2) PSO-UNLEA, a program that uses particle swarm optimization metaheuristic (PSO) for the backcalculation of pavement moduli. (3) UNPAVE, an incremental pavement design program based on the equations of the North American MEPDG and includes the computation of vehicle operating costs based on IRI. (4) PSO-PAVE, a PSO program to search for thicknesses that optimize the design considering construction and vehicle operating costs. The case studies show that the backcalculation and structural design of pavements can be optimized by PSO considering restrictions in the thickness and the selection of materials. Future developments should reduce the computational cost and calibrate the pavement performance and VOC models. (Texto tomado de la fuente)La construcciĂłn de pavimentos asfĂĄlticos en calles y carreteras es una actividad que requiere la optimizaciĂłn del consumo de cuantiosos recursos econĂłmicos y naturales. La optimizaciĂłn del diseño de pavimentos atiende objetivos contradictorios de acuerdo con la disponibilidad de recursos y las necesidades de los usuarios. Este trabajo explora el empleo de metaheurĂsticas para optimizar el diseño de pavimentos asfĂĄlticos empleando el diseño incremental basado en la predicciĂłn del deterioro y los costos de operaciĂłn vehicular (COV). Los costos son proporcionales al consumo energĂ©tico y de recursos y las emisiones contaminantes. Se revisĂł la evoluciĂłn del diseño de pavimentos asfĂĄlticos y el desarrollo de tĂ©cnicas metaheurĂsticas de optimizaciĂłn en este tema. Se desarrollaron cuatro programas de computador: (1) UNLEA, programa para el anĂĄlisis estructural de sistemas multicapa. (2) PSO-UNLEA, programa que emplea la metaheurĂstica de optimizaciĂłn con enjambre de partĂculas (PSO) para el cĂĄlculo inverso de mĂłdulos de pavimentos. (3) UNPAVE, programa de diseño incremental de pavimentos basado en las ecuaciones de la MEPDG norteamericana, y el cĂĄlculo de costos de construcciĂłn y operaciĂłn vehicular basados en el IRI. (4) PSO-PAVE, programa que emplea la PSO en la bĂșsqueda de espesores que permitan optimizar el diseño considerando los costos de construcciĂłn y de operaciĂłn vehicular. Los estudios de caso muestran que el cĂĄlculo inverso y el diseño estructural de pavimentos pueden optimizarse mediante PSO considerando restricciones en los espesores y la selecciĂłn de materiales. Los desarrollos futuros deben enfocarse en reducir el costo computacional y calibrar los modelos de deterioro y COV.DoctoradoDoctor en IngenierĂa - IngenierĂa AutomĂĄticaDiseño incremental de pavimentosElĂ©ctrica, ElectrĂłnica, AutomatizaciĂłn Y Telecomunicacione
Recommended from our members
The Expanding Landscape of Alternative Splicing Variation in Human Populations.
Alternative splicing is a tightly regulated biological process by which the number of gene products for any given gene can be greatly expanded. Genomic variants in splicing regulatory sequences can disrupt splicing and cause disease. Recent developments in sequencing technologies and computational biology have allowed researchers to investigate alternative splicing at an unprecedented scale and resolution. Population-scale transcriptome studies have revealed many naturally occurring genetic variants that modulate alternative splicing and consequently influence phenotypic variability and disease susceptibility in human populations. Innovations in experimental and computational tools such as massively parallel reporter assays and deep learning have enabled the rapid screening of genomic variants for their causal impacts on splicing. In this review, we describe technological advances that have greatly increased the speed and scale at which discoveries are made about the genetic variation of alternative splicing. We summarize major findings from population transcriptomic studies of alternative splicing and discuss the implications of these findings for human genetics and medicine
- âŠ