2,662 research outputs found
Reduced kinetic mechanisms for modelling LPP combustión in gas turbines
Reduced kinetic mechanisms for modelling LPP combustión in gas turbine
Simulation and comparative analysis of waste in concrete slabs
Construction sector generates significant amounts of waste that affects the environment and obstructs a sustainable development. The horizontal structure (slabs and roofs) is one of the building elements, by its functional requirement (geometry and layout) and volume, who uses more raw material for its constitution (potential generators of waste) On the other hand, the choice of the system to use, is typically based on criteria such as the ease of construction, the economy availability or the technological feasibility; so, from a sustainable perspective, the generation of waste has not been considered or evaluated. This work compares and analyzes four different common elements used in slabs and the possible generation of waste produced for the construction and eventual demolition of them, in order to provide a new weighting criterion in the choice.Peer ReviewedPostprint (published version
Simulation and comparative analysis of waste in concrete slabs
Construction sector generates significant amounts of waste that affects the environment and obsturcts a sustainable development. The horizontal structure (slabs and roofs) is one of the building elements, by its functional requirement (geometry and layout) and volume, who uses more raw material for its constitution (potential generators of waste) On the other hand, the choice of the system to use, is typically based on criteria such as the ease of construction, the economy availability or the tecnological feasibility; so, from a sustainable perspective, the generation of waste has not been considered or evaluated. This work compares and analyzes four different common elements used in slabs and the possible generation of waste produced for the construction and eventual demolition of them, in order to provide a new weighiting criterion in the choice.Peer ReviewedPostprint (published version
Cooperative scale-free networks despite the presence of detector hubs
Recent results have shown that heterogeneous populations are better suited to support
cooperation than homogeneous settings when the Prisoner’s Dilemma drives the evolutionary
dynamics of the system. The same occurs when the network growth is coevolving together with
the evolutionary dynamics, which also gives rise to highly cooperative scale-free networks. In the
latter case, however, the organization of cooperation is radically different with respect to the case
in which the underlying network is static. In this paper we study the structure of cooperation
in static networks grown together with evolutionary dynamics and show that the general belief
that hubs can only be occupied by cooperators does not hold. Moreover, these scale-free networks
support high levels of cooperation despite having defector hubs. Our results have several important
implications for the explanation of cooperative behavior in scale-free networks and highlight the
importance that the formation of complex systems have on its function.YM is supported by MICINN (Spain) through the Ram´on y Cajal Programme. This work has been partially supported by MICINN through Grants FIS2006-12781- C02-01, FIS2008-01240 and MOSAICO, and by Comunidad de Madrid (Spain) through Grant SIMUMAT-CM.Publicad
The reduced kinetic description of lean premixed combustion
Lean premixed methane-air flames are investigated in an effort to facilitate the numerical description of CO and NO emissions in LP (lean premixed) and LPP (lean premixed prevaporized) combustion systems. As an initial step, the detailed mechanism describing the fuel oxidation process is reduced to a four-step description that employs CO, H2, and OH as intermediates not following a steady-state approximation. It is seen that, under conditions typical of gas-turbine combustion, this mechanism can be further simplified to give a two-step reduced description, in which fuel is consumed and CO is produced according to the fast overall step CH4 + 3/2 O2 CO + 2H2O, while CO is slowly oxidized according to the overall step CO + 1/2 O2 CO2. Because of its associated fast rate, fuel consumption takes place in a thin layer where CO, H2, and OH are all out of steady state, while CO oxidation occurs downstream in a distributed manner in a region where CO is the only intermediate not in steady state. In the proposed description, the rate of fuel consumption is assigned a heuristic Arrhenius dependence that adequately reproduces laminar burning velocities, whereas the rate of CO oxidation is extracted from the reduced chemistry analysis. Comparisons with results obtained with detailed chemistry indicate that the proposed kinetic description not only reproduces well the structure of one-dimensional unstrained and strained flames, including profiles of CO, temperature, and radicals, but can also be used to calculate NO emissions by appending an appropriate one-step reduced chemistry description that includes both the thermal and the N2O production paths. Although methane is employed in the present study as a model fuel, the universal structure of the resulting CO oxidation region, independent of the fuel considered, enables the proposed formulation to be readily extended to other hydrocarbons
A Multi-Omics Analysis Pipeline for the Metabolic Pathway Reconstruction in the Orphan Species Quercus ilex
Holm oak (Quercus ilex) is the most important and representative species of the Mediterranean forest and of the Spanish agrosilvo-pastoral “dehesa” ecosystem. Despite its environmental and economic interest, Holm oak is an orphan species whose biology is very little known, especially at the molecular level. In order to increase the knowledge on the chemical composition and metabolism of this tree species, the employment of a holistic and multi-omics approach, in the Systems Biology direction would be necessary. However, for orphan and recalcitrant plant species, specific analytical and bioinformatics tools have to be developed in order to obtain adequate quality and data-density before to coping with the study of its biology. By using a plant sample consisting of a pool generated by mixing equal amounts of homogenized tissue from acorn embryo, leaves, and roots, protocols for transcriptome (NGS-Illumina), proteome (shotgun LC-MS/MS), and metabolome (GC-MS) studies have been optimized. These analyses resulted in the identification of around 62629 transcripts, 2380 protein species, and 62 metabolites. Data are compared with those reported for model plant species, whose genome has been sequenced and is well annotated, including Arabidopsis, japonica rice, poplar, and eucalyptus. RNA and protein sequencing favored each other, increasing the number and confidence of the proteins identified and correcting erroneous RNA sequences. The integration of the large amount of data reported using bioinformatics tools allows the Holm oak metabolic network to be partially reconstructed: from the 127 metabolic pathways reported in KEGG pathway database, 123 metabolic pathways can be visualized when using the described methodology. They included: carbohydrate and energy metabolism, amino acid metabolism, lipid metabolism, nucleotide metabolism, and biosynthesis of secondary metabolites. The TCA cycle was the pathway most represented with 5 out of 10 metabolites, 6 out of 8 protein enzymes, and 8 out of 8 enzyme transcripts. On the other hand, gaps, missed pathways, included metabolism of terpenoids and polyketides and lipid metabolism. The multi-omics resource generated in this work will set the basis for ongoing and future studies, bringing the Holm oak closer to model species, to obtain a better understanding of the molecular mechanisms underlying phenotypes of interest (productive, tolerant to environmental cues, nutraceutical value) and to select elite genotypes to be used in restoration and reforestation programs, especially in a future climate change scenario
Metamorphosis in the porosity of recycled concretes through the use of a recycled polyethylene terephthalate (PET) additive. Correlations between the porous network and concrete properties
In the field of construction, sustainable building materials are currently undergoing a process of technological development. This study aims to contribute to understanding the behavior of the fundamental properties of concretes prepared with recycled coarse aggregates that incorporate a polyethylene terephthalate (PET)-based additive in their matrix (produced by synthesis and glycolysis of recycled PET bottles) in an attempt to reduce their high porosity. Techniques to measure the gas adsorption, water porosity, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to evaluate the effect of the additive on the physical, mechanical and microstructural properties of these concretes. Porosity reductions of up to 30.60% are achieved with the addition of 1%, 3%, 4%, 5%, 7% and 9% of the additive, defining a new state in the behavioral model of the additive (the overdosage point) in the concrete matrix; in addition, the porous network of these concretes and their correlation with other physical and mechanical properties are also explained.Peer ReviewedPostprint (published version
Simulating use cases for the UAH autonomous electric car
2019 IEEE Intelligent Transportation Systems Conference (ITSC), Auckland, New Zealand, 27-30 Oct. 2019This paper presents the simulation use cases for
the UAH Autonomous Electric Car, related with typical driving
scenarios in urban environments, focusing on the use of hierarchical interpreted binary Petri nets in order to implement the
decision making framework of an autonomous electric vehicle.
First, we describe our proposal of autonomous system architecture, which is based on the open source Robot Operating
System (ROS) framework that allows the fusion of multiple
sensors and the real-time processing and communication of
multiple processes in different embedded processors. Then, the
paper focuses on the study of some of the most interesting
driving scenarios such as: stop, pedestrian crossing, Adaptive
Cruise Control (ACC) and overtaking, illustrating both the
executive module that carries out each behaviour based on
Petri nets and the trajectory and linear velocity that allows
to quantify the accuracy and robustness of the architecture
proposal for environment perception, navigation and planning
on a university Campus.Ministerio de Economía y CompetitividadComunidad de Madri
Propiedades en estado fresco de morteros con árido reciclado de hormigón y efecto de la relación c/a
Los residuos de construcción y demolición se han convertido en un problema urbano que resulta complejo y de un alto coste de gestión. Por este motivo, en la actualidad se está innovando en legislación medioambiental para fomentar diferentes actividades que lo mitiguen; siendo el reciclado una de las más aptas (faculta su reinserción como material de segunda generación para su nuevo uso en la construcción). En esta dirección se han realizado varios estudios de morteros en los que los residuos sustituyen diferentes porcentajes de los áridos naturales, a falta de una legislación propia que marque pautas de combinación. Sin embargo, poco se ha indagado en el comportamiento de su estado en fresco, el cual es vinculado con sus propiedades en estado endurecido a posteriori. En esta investigación se han realizado ensayos de propiedades en estado fresco (consistencia, densidad y contenido de aire) de morteros que contienen diferentes porcentajes de sustitución de áridos naturales, remplazados por áridos de hormigón reciclado (10, 20, 30, 50 y 100 %) a diferentes relaciones de cemento/arena (1:3.25, 1:4 y 1:4.74). Los resultados obtenidos muestran que los morteros con áridos reciclados reportan menor densidad, necesitan mayor cantidad de agua para lograr la consistencia requerida y presentan mayor contenido de aire que los morteros de referencia, sin sustitución de áridos reciclados.Peer ReviewedPostprint (published version
Continuous Training and Certification in Neonatal Resuscitation in Remote Areas Using a Multi-Platform Information and Communication Technology Intervention, Compared to Standard Training: A Randomized Cluster Trial Study Protocol
Background: About 10% of all newborns may have difficulty breathing and require support by trained personnel. In Peru, 90% of deliveries occur in health facilities. However, there is not a national neonatal resuscitation and certification program for the public health sector. In addition, the Andes and the Amazon regions concentrate large rural remote areas, which further limit the implementation of training programs and the accomplishment of continuous certification. Neonatal resuscitation training through the use of Information, Communication and Technology (ICT) tools, running on computers, tablets or mobile phones, may overcome such limitations. This strategy allows online and offline access to educational resources, paving the way to more frequent and efficient training, and certification processes.
Objective: To evaluate the effects of a neonatal resuscitation training and certification program that uses a Multi-Platform ICT (MP-ICT) strategy on neonatal health care in remote areas.
Methods: We propose to conduct the study through a cluster-randomized trial, where the study and analysis unit is the health care facility. Eligible facilities will include primary and secondary health care level facilities that are located in provinces with neonatal mortality rates higher than 15 per 1,000 live births. We will compare the proportion of newborns with a heart rate ≥100 beats per minute at two minutes after birth in health care facilities that receive MP-ICT training and certification implementation, with those that receive standard training and certification.
Discussion: We expect that the intervention will be shown as more effective than the current standard of care. We are prepared to include it within a national neonatal resuscitation training and certification program to be implemented at national scale together with policymakers and other key stakeholders.
Trial registration: ClinicalTrials.gov Nº NCT03210194
Status of the study: This study is enrolling participants by invitation only.
Study protocol version 1.1 – March 31st, 201
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