Un examen de las relaciones publicadas entre la velocidad y la intensidad en carreteras de dos carriles: exigencias de un modelo integrador

La comunicación se centra en examinar las diferentes formas propuestas para la relación ente la velocidad y la intensidad en carreteras de dos carriles. En los pasados 50 años se han propuesto formas rectas, cóncavas, convexas y cóncavo-convexas. Los investigadores no han formulado ningún intento de explicar las diferencias. Parece que la forma puede depender de las posibilidades de adelantamiento, y al relación entre velocidades de vehículos lentos y rápidos. Se comienza por revisar las formas publicadas, y se resumen las diferencias principales. Se examinan las diferentes posibilidades, y se formulan las exigencias que debe cumplir un modelo que satisfaga las distintas observaciones realizadas. Se concluye que los factores que más importan son las posibilidades de adelantamiento, la longitud del tramo de carretera y las diferencias de velocidades entre vehículos lentos y rápido

Efecto de los regimenes de perturbación en la regeneración de Quercus rotundifolia Lam. en el NE de Portugal

El “monte de Morais” (NE Portugal) es una de las mayores unidades continuas de serpentinas en Portugal, con un elevado interés geológico y botánico y que forma parte de la Red Natura 2000. Es el área más representativa de las rocas ultrabásicas lusitano-durienses, cubierta por diversas comunidades de especies endémicas. Su vegetación está dominada por Quercus rotundifolia Lam. siendo también importante la presencia de Quercus suber L., Juniperus oxycedrus Sibth. & Sm y Quercus faginea Lam. En los últimos años, el monte fue objeto de diferentes intervenciones consistentes en la aplicación de desbroces mecánicos (parcelas perturbadas) en determinadas áreas del monte y, otras zonas, donde no se aplicó desbroce, fueron destinadas a refugio de caza (parcelas no perturbadas). El objetivo de este estudio fue evaluar el efecto del desbroce mecánico sobre la sustentabilidad del encinar. Se determinó la cobertura vegetal del sotobosque, la regeneración de la encina (número plántulas/m2) y su tipología en zonas perturbadas y no perturbadas. Los resultados muestran un incremento de la cubierta herbácea en las parcelas perturbadas mientras que las no perturbadas se favoreció la presencia de arbustos. La regeneración de la encina en las parcelas perturbadas se redujo drásticamente en comparación con las no perturbada

Anecdotario político

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

Reduction of sulfur oxides in exhaust gases

El trabajo versará sobre el nombramiento y descripción de la normativa más reciente sobre el control de las emisiones de gases contaminantes por parte de la industria marítima, centrándose en la emisión de óxidos de azufre SOx. Después se detallarán las medidas disponibles incluidas y certificadas por las autoridades competentes que las compañías deberán adoptar para cumplir con la normativa. Las opciones disponibles en este caso son utilizar combustible bajo en azufre que cumpla las disposiciones de las autoridades, utilizar motores consumiendo gas natural, o instalar una torre de lavado de gases de escape.Abstract: The work will focus on the appointment and description of the latest regulation on the control of polluting gases emissions by the maritime industry, focusing on the emission of sulfur oxides SOx. Afterwards, the available measures included and certified by the competent authorities that the companies will take to comply with the regulations will be detailed. The available options are using low Sulphur fuel oil, using engines that burn natural gas, and installing an exhaust gas scrubber.Máster en Ingeniería Marin

Physically and chemically modified starches as texturisers of low-fat milk gels

In reduced fat-milk gels lack of fat globules results in undesirable texture changes. This study evaluates application of chemically modified (E-1412,E-1414,E-1422,E-1442), pregelatinized, and both pregelatinized (PG) and chemically modified (PGE-1414) starches as fat replacers. Skimmed milk was substituted with 2% of each starch. The pH and rheological evolution during the acidification process, viscosity of the stirred gels, texture of the set gels and syneresis of all gels were measured. Skimmed and full-fat milk gels were included as controls. All starches had lower or higher pH values, than skimmed or full fat milk gels during acidification. Gelation time was reduced for all starches compared to the skimmed milk gel. For both stirred and set milk gels, with PG, PGE-1414, E-1422 and E-1442 had viscosity/texture values similar or higher to those found for full fat milk gel. For syneresis, E-1412 had drastically increased values when compared with both controls.  Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2)European Regional Development Fund (FEDER

Underwater Cultural heritage risk assessment methodology for wave-induced hazards: The showcase of the Bay of Cadiz

Coastal areas are characterized by high energetic conditions associated to the wave transformation process and by numerous underwater cultural heritage (UCH) sites whose preservation is crucial given their cultural and economic value. UCH management requires a decision support system to prioritize UCH interventions and actions for long-term preservation. This paper presents a novel UCH risk assessment methodology to quantitatively assess the impact of wave-induced hazards on UCH in coastal environments at a local level and the screening of UCH sites at risk. The UCH risk is calculated as a function of vulnerability (depending on archaeological materials, slope, and seabed type), hazard (decontextualization, scouring, and erosive wear), and exposure computed for the UCH sites registered in an archaeological database. The procedure was validated at two shipwreck sites, Bucentaure and Fougueux, in the Bay of Cadiz. An agreement between the risk index value and the in situ measurements of the rates of scouring and corrosion (used as a proxy of erosive wear) was observed. The methodology was tested in the Bay of Cadiz using an archaeological database containing 56 UCH sites. It allowed identifying the UCH sites at high risk: six are at risk of decontextualization, four are in peril of scouring erosion, and two are at risk of erosive wear. Two UCH sites at high risk of at least two hazards were also identified. This UCH risk assessment methodology is a stepping stone towards a decision support system that will give priority to research, prospection, management, and protection measures in the UCH sites analyzed to ensure their preservation in a context of climate change in the era of a sustainable blue economy.18 página

Methods for autonomous wristband placement with a search-and-rescue aerial manipulator

A new robotic system for Search And Rescue (SAR) operations based on the automatic wristband placement on the victims’ arm, which may provide identification, beaconing and remote sensor readings for continuous health monitoring. This paper focuses on the development of the automatic target localization and the device placement using an unmanned aerial manipulator. The automatic wrist detection and localization system uses an RGB-D camera and a convolutional neural network based on the region faster method (Faster R-CNN). A lightweight parallel delta manipulator with a large workspace has been built, and a new design of a wristband in the form of a passive detachable gripper, is presented, which under contact, automatically attaches to the human, while disengages from the manipulator. A new trajectory planning method has been used to minimize the torques caused by the external forces during contact, which cause attitude perturbations. Experiments have been done to evaluate the machine learning method for detection and location, and for the assessment of the performance of the trajectory planning method. The results show how the VGG-16 neural network provides a detection accuracy of 67.99%. Moreover, simulation experiments have been done to show that the new trajectories minimize the perturbations to the aerial platform.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Creep and shrinkage of self compacting concrete of medium-strenght

Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compacting. SCC, developed in Japan in the 1980s, provides a present-day and attractive challenge for many researchers, as the long list of papers on the topic corroborates. Nevertheless, the durability of SCC, especially medium-low strength SCC, provides the researcher with opportunities for study in depth. This paper deals with the shrinkage and creep of SCC: three SCC mixtures, with 30 MPa compressive strength, are studied. The main differences among the SCCs involve the type of the cement: one SCC with type I cement and two SCCs with blended cements. The shrinkage and creep of the three SCCs are studied and compared. Fresh properties and mechanical properties are also evaluated. The shrinkage strains and creep are calculated by means of ACI 209 and Eurocode 2 models. These models overestimate the shrinkage strains and undervalue the creep for the studied concretes

Retracción y fluencia de hormigón autocompactante de resistencia moderada

Los estudios sobre el hormigón autocompactante se han centrado en obtener las dosificaciones óptimas, pero hay desconocimiento acerca de su comportamiento a largo plazo, en especial en hormigones de resistencia moderada. Este trabajo estudia la fluencia y retracción de tres hormigones autocompactantes de resistencia moderada (resistencia característica aproximada de 25 MPa), cuya dosificación y propiedades mecánicas son casi iguales, pero que emplean cementos con distintos tipos de adición. En los tres casos se emplea filler calizo. El trabajo presenta los resultados de los ensayos de retracción y fluencia, que son comparados con las predicciones del Código Modelo CEB-FIP, del ACI Concrete Practice Manual y del Euro Code 2. Además también se ha obtenido el volumen total de poros y su distribución por tamaños mediante el ensayo de porosimetría por intrusión de mercurio

Dealing with the Resolubility of Evolution Algebras

Although since their introduction by Tian in 2004, evolution algebras have been the subject of a very deep study in the last years due to their numerous applications to other disciplines, this study is not easy since these algebras lack an identity that characterizes them, such as the identity of Jacobi, for Lie algebras or those of Leibniz and Malcev for those corresponding algebras. In this paper we deal with the concepts of solvability and nilpotency of these evolution algebras. Some novel results on them obtained from using the evolution operator of these algebras are given and some examples illustrating these results are also shown. The main result obtained states that an evolution algebra is solvable if and only if its structure matrix is nilpotent, which implies, in turn, that the solvability and the nilpotency indices of that algebra coincide provided the corresponding evolution operator is an endomorphism of the algebra