Aproximación analítica de consumo de combustible y comportamiento periódico para un vehículo que viaja a través de una serie de semáforos

In this paper, we present a piecewise smooth system, that describes the dynamics of a single vehicle moving through a street that has a sequence of lights that turn on and off with a specific frequency. The model presents three dynamic ways: accelerated, decelerated and zero state. Besides, we show the description of the mathematical model used to simulate the system. The simulation was developed under an event-based scheme and implemented in Matlab. To make the numerical analysis, we take as a parameter study the cycle traffic light, which provides benefits to vehicular traffic system due to its configuration is achieved implementing optimization strategies for the phenomenon of green wave and reduces the travel time as the vehicle minimizes the number of stops along the road. Also, the stability was studied for the periodic orbits one and two. Finally, we made an approximation of fuel consumption. We assume that this is proportional to the mechanical energy produced by the motor. From this point of view, it can be concluded that it is possible to apply modeling and simulation strategies based on dynamic systems to understand the complex behaviors associated with the travel of vehicles in a traffic controlled by traffic lights.En el siguiente artículo, se presenta un sistema suave por tramos que describe la dinámica de un vehículo que se mueve a través de una calle con semáforos que se encienden y apagan con una frecuencia específica. El modelo presenta tres comportamientos dinámicos: acelerado, desacelerado y detenido. Además, se muestra la descripción del modelo matemático utilizado para simular el sistema. La simulación se desarrolló bajo un esquema basado en eventos y se implementó en Matlab. Para realizar el análisis numérico, se toma como parámetro el ciclo de los semáforos, que mejora el sistema de tráfico vehicular debido a que con su configuración se logran implementar estrategias de optimización permitiendo que los vehículos se desplacen en ola verde y reduzcan el tiempo de viaje, minimizando así, el número de paradas a lo largo del camino y reduciendo el consumo de combustible debido a las paradas y aceleradas. Además, se estudió la estabilidad de las órbitas periódicas uno y dos que presenta el modelo de simulación, así como sus implicaciones dinámicas. Finalmente, se presenta una propuesta para calcular el consumo de combustible, asumiendo que es proporcional a la energía mecánica producida por el motor, resulta en una propuesta novedosa que permite a las secretarias de movilidad comprender los comportamientos de los vehículos en vías principales de las ciudades. Desde este punto de vista, se puede concluir que es posible aplicar estrategias de modelado y simulación basadas en sistemas dinámicos para comprender los comportamientos complejos asociados al desplazamiento de los vehículos en una via controlada por semáforos

“Education Network” a new way to teach Chemistry

The complexity of chemistry has implications for the teaching of chemistry. That chemistry is a very complex subject. The majority of the students at University think that chemistry is a difficult discipline and they have difficulty in understanding the concepts. Moreover, students' interest in chemistry decreases the first year at university. The reason for this decrease might be that the contents of chemistry laboratory classes are boring, out of date and lacking of dynamism that students experience through visual media tools. For these reasons, new programs and methodologies should be developed. Those are based on making chemistry relevant through problem solving and collaborative learning hold promise for reforming chemistry education. It is about an education according to circumstances, which is adapted to context and virtual behaviour of people. It's time to CRUSH boredom by transforming your classroom into an Escape Room adventure. School-based escape games are a great teaching tool. The students while playing, learn. The most important point is that they won’t realize they’re doing both at the same time. In this work, an educational gamification experience based on the escape room concept was developed. The first (Do It Yourself) DIY Escape Room was built the year before at Mechanical Engineer Degree started, that took more than three weeks of work. It was presented to other professors to the same subject at different degrees. That DIY Escape Room was modified and adapted to each group. Each professor changed the clues, problems and so on in order to orientate the topic as much as possible to their students.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

3D pore analysis of sedimentary rocks

A 3D representation of the internal structure and fabric of sedimentary rocks is of paramount interest to evaluate their structural parameters such as porosity, pore-size distribution and permeability. The classical experimental technique to evaluate the pore space volume and pore size distribution is the Mercury Intrusion Porosimetry (MIP). Computer-based methods use 3D imaging technologies such as Computer Tomography (CT) scanned images to construct and evaluate a 3D virtual representation of the internal pore distribution. In this work, based on a three samples set of sandstone, we apply two numerical (computer-based) methods in order to reconstruct and analyse the internal pore network, and compare it with the results obtained by MIP analysis. The first numerical method performs a virtual simulation of MIP. The second one obtains a graph of pores using a sphere-filling based approach. For all methods, we compute the global porosity and the pore-size distribution. Moreover, with the numerical methods, we obtain the total porosity and a graph representing the pore space that can be visualized with 3D illustration techniques.Postprint (published version

Uncertainties in atmospheric chemistry modelling due to convection parameterisations and subsequent scavenging

Moist convection in global modelling contributes significantly to the transport of energy, momentum, water and trace gases and aerosols within the troposphere. Since convective clouds are on a scale too small to be resolved in a global model their effects have to be parameterised. However, the whole process of moist convection and especially its parameterisations are associated with uncertainties. In contrast to previous studies on the impact of convection on trace gases, which had commonly neglected the convective transport for some or all compounds, we investigate this issue by examining simulations with five different convection schemes. This permits an uncertainty analysis due to the process formulation, without the inconsistencies inherent in entirely neglecting deep convection or convective tracer transport for one or more tracers. <br><br> Both the simulated mass fluxes and tracer distributions are analysed. Investigating the distributions of compounds with different characteristics, e.g., lifetime, chemical reactivity, solubility and source distributions, some differences can be attributed directly to the transport of these compounds, whereas others are more related to indirect effects, such as the transport of precursors, chemical reactivity in certain regions, and sink processes. <br><br> The model simulation data are compared with the average regional profiles of several measurement campaigns, and in detail with two campaigns in fall and winter 2005 in Suriname and Australia, respectively. <br><br> The shorter-lived a compound is, the larger the differences and consequently the uncertainty due to the convection parameterisation are, as long as it is not completely controlled by local production that is independent of convection and its impacts (e.g. water vapour changes). Whereas for long-lived compounds like CO or O<sub>3</sub> the mean differences between the simulations are less than 25%), differences for short-lived compounds reach up to ±100% with different convection schemes. <br><br> A rating of an overall "best" performing scheme is difficult, since the optimal performance depends on the region and compound

Time-varying volume visualization

Volume rendering is a very active research field in Computer Graphics because of its wide range of applications in various sciences, from medicine to flow mechanics. In this report, we survey a state-of-the-art on time-varying volume rendering. We state several basic concepts and then we establish several criteria to classify the studied works: IVR versus DVR, 4D versus 3D+time, compression techniques, involved architectures, use of parallelism and image-space versus object-space coherence. We also address other related problems as transfer functions and 2D cross-sections computation of time-varying volume data. All the papers reviewed are classified into several tables based on the mentioned classification and, finally, several conclusions are presented.Preprin

Vesiculation and Quenching During Surtseyan Eruptions at Hunga Tonga-Hunga Ha'apai Volcano, Tonga

Surtseyan eruptions are shallow to emergent subaqueous explosive eruptions that owe much of their characteristic behavior to the interaction of magma with water. The difference in thermal properties between water and air affects the cooling and postfragmentation vesiculation processes in magma erupted into the water column. Here we study the vesiculation and cooling processes during the 2009 and 2014–2015 Surtseyan eruptions of Hunga Tonga‐Hunga Ha'apai volcano by combining 2‐D and 3‐D vesicle‐scale analyses of lapilli and bombs and numerical thermal modeling. Most of the lapilli and bombs show gradual textural variations from rim to core. The vesicle connectivity in the lapilli and bombs increases with vesicularity from fully isolated to completely connected and also increases from rim to core in transitional clasts. We interpret the gradual textural variations and the connectivity‐vesicularity relationships as the result of postfragmentation bubble growth and coalescence interrupted at different stages by quenching in water. The measured vesicle size distributions are bimodal with a population of small and large vesicles. We interpret this bimodality as the result of two nucleation events, one prefragmentation with the nucleation and growth of large bubbles and one postfragmentation with nucleation of small vesicles. We link the thermal model with the textural variations in the clasts—showing a dependence on particle size, Leidenfrost effect, and initial melt temperature. In particular, the cooling profiles in the bombs are consistent with the gradual textural variations from rim to core in the clasts, likely caused by variations in time available for vesiculation before quenching

Single-nucleotide polymorphisms: analysis by mass spectrometry

Matrix-assisted laser desorption-ionization (MALDI) mass spectrometry has evolved as a powerful method for analyzing nucleic acids. Here we provide protocols for genotyping single-nucleotide polymorphisms (SNPs) by MALDI based on PCR and primer extension to generate allele-specific products. Furthermore, we present three different approaches for sample preparation of primer-extension products before MALDI analysis and discuss their potential areas of application. The first approach, the 'GOOD' assay, is a purification-free procedure that uses DNA-modification chemistry, including alkylation of phosphorothioate linkages in the extension primers. The other two approaches use either solid-phase extraction or microarray purification for the purification of primer-extension products. Depending on the reaction steps of the various approaches, the protocols take about 6–8 hours

Stratospheric dryness

International audienceThe mechanisms responsible for the extreme dryness of the stratosphere have been debated for decades. A key difficulty has been the lack of models which are able to reproduce the observations. Here we examine results from a new atmospheric chemistry general circulation model (ECHAM5/MESSy1) together with satellite observations. Our model results match observed temperatures in the tropical lower stratosphere and realistically represent recurrent features such as the semi-annual oscillation (SAO) and the quasi-biennual oscillation (QBO), indicating that dynamical and radiation processes are simulated accurately. The model reproduces the very low water vapor mixing ratios (1?2 ppmv) periodically observed at the tropical tropopause near 100 hPa, as well as the characteristic tape recorder signal up to about 10 hPa, providing evidence that the dehydration mechanism is well-captured, albeit that the model underestimates convective overshooting and consequent moistening events. Our results show that the entry of tropospheric air into the stratosphere at low latitudes is forced by large-scale wave dynamics; however, radiative cooling can regionally limit the upwelling or even cause downwelling. In the cold air above cumulonimbus anvils thin cirrus desiccates the air through the sedimentation of ice particles, similar to polar stratospheric clouds. Transport deeper into the stratosphere occurs in regions where radiative heating becomes dominant, to a large extent in the subtropics. During summer the stratosphere is moistened by the monsoon, most strongly over Southeast Asia

Surge in global metal mining threatens vulnerable ecosystems

Mining activities induce profound changes to societies and the environment they inhabit. With global extraction of metal ores doubling over the past two decades, pressures related to mining have dramatically increased. In this paper, we explore where growing global metal extraction has particularly taken effect. Using fine-grain data, we investigate the spatial and temporal distribution of mining of nine metal ores (bauxite, copper, gold, iron, lead, manganese, nickel, silver and zinc) across approximately 3,000 sites of extraction worldwide between 2000 and 2019. To approach the related environmental implications, we intersect mining sites with terrestrial biomes, protected areas, and watersheds categorised by water availability. We find that 79% of global metal ore extraction in 2019 originated from five of the six most species-rich biomes, with mining volumes doubling since 2000 in tropical moist forest ecosystems. We also find that half of global metal ore extraction took place at 20 km or less from protected territories. Further, 90% of all considered extraction sites correspond to below-average relative water availability, with particularly copper and gold mining occurring in areas with significant water scarcity. Our study has far-reaching implications for future global and local policy and resource management responses to mitigate the negative effects of the expected expansion of metal mining