Steel is responsible for providing resistance to flexotraction to reinforced concrete structures. Steel is responsible for providing reinforced concrete structures with a flexural strength. For this reason, it is important to study its behaviour under different tensile states. This study used measuring equipment that was able to determine variations in magnetic properties of B500-SD steel bars during standard tensile tests. The magnetic field generated by a Helmholtz coil was collected through a secondary circuit. This enables the induced electromotive force to relate with the steel deflection stages when subjected to the tests. Moreover, it was possible to determine the variation of magnetic permeability when submitting 12mm and 16mm diameter bars to different tensile states. This method could prove extremely useful in determining the tensile state of ribbed steel bars that are embedded into the concrete structure.

The construction and demolition waste can be used as an alternative with a lower environmental impact compared to the use of natural aggregates in the concrete and mortar manufacture. In this work, it has been performed an analysis of lime and cement mortar properties made with ceramic recycled aggregates reinforced with three types of fibers: glass, basalt and carbon. An experimental campaign has been carried out which includes the chemical and physical characterization of the materials and the statistical analysis of the results obtained. It has been proven that the addition of fibers improves the mechanical properties of the material and decreases its retraction, which favors the incorporation of recycled aggregates in the mortars manufacture. Based on the results obtained, it can be stated that carbon fiber is the best performing reinforcing material, as it has been demonstrated in this statistical analysis.

Traditional classroom teaching methodology does not adjust to the current necessities of the students, however long presentations, quantitative evaluation and rote learning still dominate in the classroom, which limits the student to retain and repeat information provided by the teacher. A change in the education system becomes necessary. This change has to be based on the interaction between the equals, the contextualization and collaborative work, where teaching contents would have an applied approach with a student as a centre of the learning-teaching process and based on the qualitative and formative assessment system. In this work, the contents of the subject Physics and Chemistry of the 3rd year of compulsory secondary education were broken down, where appeared the concepts that can be introduced in the classroom with a help of animations. Moreover, a list of problems was presented, that allows students to discover the importance of the explained scientific contents and interrelate them to famous movies. It is a multidisciplinary project as it works in cooperation with such subject as Language and Literature and Plastic, Visual and Artistic Education. The work pretends to lay the foundations so that any teacher could apply this methodology, collection activities and assessment exercises based on the learning standards of the curriculum of secondary education, adding a temporization so that it can be used with success during the study period.

En la actualidad existe una amplia gama de sistemas y materiales que se emplean como atenuadores del ruido de impacto, ofreciendo buenas prestaciones a la hora de evitar la transmisión de vibraciones a través de los forjados. En este trabajo, se han elaborado placas de mortero de cuatro centímetros de espesor con cuatro tipos de árido diferentes combinados con distintas tipologías de aislamiento. Aprovechando la menor densidad de los morteros elaborados con árido reciclado, se ha llevado a cabo una investigación en la que se propone sustituir el 100% del árido natural por árido reciclado para la fabricación de morteros empleados en el sistema de losa flotante, ya que ofrecen una solución más eficiente desde el punto de vista acústico. Los morteros elaborados con áridos reciclados de cerámica y mixto los que presentan la solución óptima para atenuar impactos producidos sobre la superficie, reduciendo hasta en un 20% la velocidad de transmisión de impactos frente a sus homólogos elaborados con árido natural.

Mortars elaborated with recycled aggregates raise two main difficulties: lower mechanical strengths and higher shrinkage compared to traditional mortars. For this reason, fibers were used to improve the properties. Steel fibers are the most employed for their ferromagnetic qualities, what helps to orient them influenced by magnetic field. This paper argues how recycled mortars with steel fiber oriented under the influence of 500 mT field reach flexural strengths 10% higher than those with non-oriented fibers. Thus, mechanical strengths are closer to traditional mortars. Inclusion of fibers in mortar is suitable for obtaining shrinkage values similar to those obtained in traditional mortars. (C) 2019 Published by Elsevier Ltd.

In this work, a wide variety of teamwork techniques are collected, detailed in schematic way and validated through the university teaching experience at the Universidad Politecnica of Madrid. It is also indicated the way to carry them out within the classroom through practical examples. With these techniques, it is intended to provide to university professors of new resources and clarification of the other ones resources already known to university professors to facilitate the work within the classroom, including new active methodologies that are in line with the objectives of the Bolonia Plan for university education. In addition, different ways of evaluating their effectiveness within the classroom and understanding their scope are also presented, with the idea of being able to improve the quality of teaching based on the experience within the classroom. The work has been carried out jointly by professors from different areas of knowledge and university centers in the country. This has made it possible to classify the different techniques presented according to their effectiveness in the different subjects and areas used.

Currently there is a wide range of systems and materials that are used as impact noise absorbers, offering good performance avoiding the transmission of vibration through the forgings. In this research, four centimeters thick sheets of mortar were fabricated using four types of different aggregates combined with different typologies of insulation. Taking advantage of the minor density of mortars elaborated with recycled aggregates, it was proposed to substitute 100% of natural aggregates with recycled aggregates in order to fabricate mortars used in floating slab systems, as they offer more efficient solution from the acoustic point of view. The mortars elaborated with ceramic and mixed recycled aggregate presents the best solution to mitigate impacts produced on the surface reducing up to 20% of speed of impact transmission compared to mortars elaborated with natural aggregates.

ResumenLa contribución de la Energía Solar Térmica para las instalaciones de calefacción de agua caliente sanitaria y piscinas climatizadas se ha incrementado notablemente desde la entrada en vigor del Código Técnico de la Edificación, superando ya los dos millones de metros cuadrados de ocupación. En este trabajo se establecen unas pautas para la correcta revisión y peritación de este tipo de instalaciones, tomando por referencia una instalación real con 43 captadores de placa plana correspondientes al centro Salesianos Carabanchel, con el objeto de facilitar la intervención a aquellos profesionales de la edificación que estén inmersos en el ámbito de la rehabilitación.AbstractThe contribution of Solar Thermal Energy for heating hot water and heated pools has increased significantly since the entry into force of the Technical Building Code, already exceeding the two million square meters of occupation. In this work some guidelines for proper review and inspection of such facilities are established, taking by reference a real installation with 43 collectors flat plate corresponding to the center Salesian Carabanchel, in order to facilitate the involvement of those building professionals who are engaged in the field of rehabilitation.

Nowadays, geometric analytic work is very disassociated from graphic constructions which originated its beginning in 17th century. Mathematics and Drawing went hand in hand since the birth of human thought; therefore it seems odd to try to sever their own learning from Curricular Design. With this work, to join the teaching of both subjects is proposed from an interdisciplinary perspective, that which permits a better knowledge of the studied subject without diminishing importance of both subjects. For that purpose, we are going to focus on contents of 3 degrees E.S.O. school grade and we are going to propose joint activities which are being working currently in an isolated way in Mathematics and Visual and Manual Arts subjects, studying the viability of the project.

Computer controlled power supplies are usually expensive when high performance (power, wide voltage range, low ripple factor and low response time) are required. This paper presents a simple and effective computer controlled DC system based on a commercial V/f inverter combined with a three-phase bridge rectifier and a LC power filter. Because of the widely variable frequency range of the V/f inverter when a wide range of voltage is required, amorphous or ferromagnetic core coils are avoided, and air core coils become an excellent solution to implement the filter and increase the efficiency of the power system. The proposed method for designing the LC filter is based on the full dynamic model of the filter-load set and the selection of the desired poles of the system according to the load to be coupled. The proposed topology lets obtain good time responses (setting time less than 100 ms) and good ripple factor (less than 1%) without any overshooting, even when low voltage output is required.

Actually the issue of daylighting in Architecture, in its technical aspects, is booming due to the increased rates for electricity expenses and the consequent energy saving aim. The best use made of daylight, leads to the lower contribution of artificial light needed and a more sustainable building.The Spanish Technical Building Code (CTE), Book 10 DB HE Energy Saving, Section 3: Energy Efficiency of Lighting Installations, applied to indoor lighting installations, refers to one of the calculations required to be shown on the project report is maintained average horizontal illuminance on the working plane, which can be formalized either manually or through a computer program.In this paper a new way to teach the concept of illuminance to architectural students is introduced, making use of a scale model of the placeto study, from a theoretical and experimental viewpoint. For that, photometric sensors have been placed in different positions of the model, in order to show students the importance of the proper choice of luminaries considering windows and pillars enclosure.The procedure outlined is valid for existing, under construction or project enclosures.

The present work has as main aim to make a small introduction about the types of steels, specially the ones used in the construction industry. This material is appreciated in construction due to its many advantages as strengths, resistance, adaptability and flexibility in design, durability, recyclability,...; even thou its also has week points like a low resistance to fire, weak against corrosion and a high initial cost compared with other materials.There are a high variety of ways to classify steel. So, it is very important to the building engineering students to know the classification of steel will be focused on the chemical composition of the steel, as it is the most common way of classifying it. The different types of steel will be grouped in four types: carbon steel, alloy steel, stainless steel and tool steel.In carbon steel the mainalloying constituent is carbon, in a range between 0.12% and 2%. It may also content small amounts of other elements like manganese, sulphur, phosphorus and silicon. Variations in the carbon content of carbon steel can modify its mechanical properties, for example, with an increase in the carbon content from 0.01 to 1.5% in the alloy, its strength and hardness increases but still such an increase beyond 1.5% causes appreciable reduction in the ductility and malleability of the steel. Alloy steel is a term used referring to steels with other alloying elements in addition to the carbon. The content of this alloying element is between 1.0% and 50% by weight. The most common alloying elements used in this type of steel are manganese, nickel, chromium, molybdenum, vanadium, silicon, and boron; less common alloyants are aluminium, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium. By varying the alloy proportions steel properties such as hardenability, corrosion resistance, strength, formability, weldability or ductility can be manipulated.Stainless steel is the alloy of any type of iron that contains at least 10.50 % of chromium and no more than 1.20 % of carbon. It also may content other alloy elements such as nickel or molybdenum. These steels can be divided into four groups based on their crystalline structure. Tool steels is a variety of carbon and alloy steels, its carbon content ranges between 0.7% and1.5%, it also contains tungsten, molybdenum, cobalt and vanadium in varying quantities to increase heat resistance and durability. They are ideal for cutting and drilling equipment, this suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures (red-hardness).

Given the current importance of daylighting in buildings, it is considered essential that future architects and building engineers perform some experimental practice to learn how to measure global horizontal illuminance and to be able to determine its distribution in an enclosure at different times of the day and in different seasons of the year.For the development of these practices, students will have to make scale models of the classrooms studied. They will have at their disposal photometric sensors (LI-210 SA) to be distributed appropriately in these models to measure global illuminances for several days, recording all measurements in a datalogger. Then these data will be processed with appropriate software to determine the daily evolution and illuminance distribution on the work plane.As a complementary study, students will also determine the distribution of global horizontal illuminance in the classrooms by a computer program in order to carry out a comparative study of the results obtained by both methods.

Transcranial magnetic stimulation (TMS) is an attractive research and possibly therapeutic tool for non-invasive central nervous system stimulation. However, relatively little is known about the direction, magnitude and distribution of induced electric field and current flows in tissue, and optimal setup characteristics as well as appropriate sham stimulation conditions remain largely undetermined, hampering reproducibility. Asymmetric charge-balanced stimulation waveforms are defined and used for central nervous system stimulation with selective stimulation of either neuronal cell bodies or axon fibers of passage in favour of the other. A pre-pulse is followed by an opposite polarity stimulation pulse, with the pre-pulse being relatively low-amplitude and long-duration as compared to the stimulation pulse. The polarity of the pre-pulse and stimulation pulse control the selectivity of stimulation with respect to neuronal cell bodies versus axon fibers of passage. The waveform used in the stimulation method optionally includes a zero-amplitude phase having a duration of 0 to 500 microseconds.

In this paper we show a system based on the resistivity measurement of samples of gray cast iron by the Van der Pauw method to calculate the silicon content in the samples. Twenty five trials have been carried out, studying resistive and metallographic characteristics of the samples. This has demonstrated that it is possible to obtain, by this method, the silicon content in molten flat with low content of alloying elements, also the content of chromium in series smelters where the rate of silicon remains constant.

En este trabajo se presenta un sistema basado en la medida de la resistividad de las muestras de la fundición gris mediante el método de Van der Pauw para evaluar el contenido de silicio presente en dichas muestras. Se han realizado 25 ensayos diferentes y se han estudiado las características resistivas y metalográficas de todas las muestras, demostrando que es también posible obtener mediante este método el contenido de silicio en fundiciones con contenidos bajos de aleantes o el contenido de cromo en series de fundiciones en las que la tasa de silicio se mantenga constante y conocida.

In the last years, many analyses from acoustic signal processing have been used for different applications. In most cases, these sensor systems are based on the determination of times of flight for signals from every transducer. This paper presents a flat plate generalization method for impact detection and location over linear links or bars-based structures. The use of three piezoelectric sensors allow to achieve the position and impact time while the use of additional sensors lets cover a larger area of detection and avoid wrong timing difference measurements. An experimental setup and some experimental results are briefly presented.

This work describes an acoustic system that allows the automatic detection and location of mechanical impacts on metallic based structures, which is suitable in robotics and industrial applications. The system is based on the time delays of propagation of the acoustic waves along the metallic based structure and it determines the instant and the position when and were the impact has been produced by piezoelectric sensors and an electronic-computerized system. We have obtained that for distance impact of 40 cm and 50 cm the time delay is 2 s and 72 s respectively.

In this work, a simple device for controlling the desired relative position between the fixed opto-sensor set, and the mobile tip is presented. The opto-sensor houses both, emitter and detector, in a single package; this feature facilitates a simpler mechanical design with respect to the cases where emitter and detector are separated components. This sensor arrangement contains an infrared LED emitter and a matched IC photodetector. A bifurcated lens-allocated into the own package above these active elements-focuses a small spot in front of the package. The obtained photocurrent depends on the magnitude of the reflected signal, and hence, the distance to the reflector. Therefore, the sensor response depends on the relative position between the opto-sensor and the reflectance surface. By an adequate and simple electronics system, a feedback current is applied to the magnetic coil based actuator, which compensates the measured displacement, returning the actuator tip to the desired position.