Open Access
Characterisation of mechanical energy absorbers developed to complement of roll-over protection structures in agricultural vehicles
(Elsevier, 2019-10-25) Latorre Biel, Juan Ignacio; Benito Amurrio, Marta; Pérez Ezcurdia, Amaya; Arana Navarro, Ignacio; Alfaro López, José Ramón; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
Roll-over protection structures (ROPS) and the use of safety belt is a successful combination in agricultural vehicles. If during an accident, a vehicle overturns, a ROPS is designed to deform plastically, absorbing potential energy of the vehicle, while not infringing the safety volume around the driver. The addition of mechanical energy absorbers (MEA) to a ROPS might enhance this behaviour, improving the safety provided. A disc-shaped mechanical energy absorber, designed for this purpose, is analysed and some geometrical and manufacturing features that influence their behaviour are described. Tensile tests of 6 different variants of this absorber have been carried out. The obtained loadedisplacement curves have been linearized to facilitate the calculation of quantitative parameters that can be used to characterise and compare the behaviour of the tested elements. The relation between some geometrical and manufacturing features of the absorbers and the calculated parameters is discussed. The results show that the proposed mechanical energy absorbers present enough geometrical and manufacturing adjustable variables to cover a wide range of applications.
Open Access
Experimental study of the performance and emission characteristics of an adapted commercial four-cylinder spark ignition engine running on hydrogen-methane mixtures
(Elsevier, 2014) Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Marcelino Sádaba, Sara; Pérez Ezcurdia, Amaya; Benito Amurrio, Marta; Sáinz Casas, David; Gandía Pascual, Luis; Ingeniería; Ingeniaritza
The use of hydrogen/methane mixtures with low methane contents as fuels for internal combustion engines (ICEs) may help to speed up the development of the hydrogen energy market and contribute to the decarbonization of the transportation sector. In this work, a commercial 1.4 L four-cylinder Volkswagen spark-ignition engine previously adapted to operate on pure hydrogen has been fueled with hydrogen/methane mixtures with 5–20 vol.% methane (29.6–66.7 wt.%). An experimental program has been executed by varying the fuel composition, air-to-fuel ratio (λ), spark advance and engine speed. A discussion of the results regarding the engine performance (brake torque, brake mean effective pressure, thermal efficiency) and emissions (nitrogen oxides, CO and unburned hydrocarbons) is presented. The results reveal that λ is the most influential variable on the engine behavior due to its marked effect on the combustion temperature. As far as relatively high values of λ have to be used to prevent knock, the effect on the engine performance is negative. In contrast, the specific emissions of nitrogen oxides decrease due to a reduced formation of thermal NOx. A clear positive effect of reducing the spark advance on the specific NOx emissions has been observed as well. As concerns CO and unburned hydrocarbons (HCs), their specific emissions increase with the methane content of the fuel mixture, as expected. However, they also increase as λ increases in spite of the lower fuel concentration due to a proportionally higher reduction of the power. Finally, the effect of the increase of the engine speed is positive on the CO and HCs emissions but negative on that of NOx due to improved mixing and higher temperature associated to intensified turbulence in the cylinders.
Open Access
Conversion of a gasoline engine-generator set to a bi-fuel (hydrogen/gasoline) electronic fuel-injected power unit
(Elsevier, 2011) Sáinz Casas, David; Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Sopena Serna, Carlos; Guelbenzu, E.; Pérez Ezcurdia, Amaya; Benito Amurrio, Marta; Marcelino Sádaba, Sara; Arzamendi Manterola, Gurutze; Gandía Pascual, Luis; Ingeniería; Ingeniaritza
The modifications performed to convert a gasoline carbureted engine-generator set to a bi-fuel (hydrogen/gasoline) electronic fuel-injected power unit are described. Main changes affected the gasoline and gas injectors, the injector seats on the existing inlet manifold, camshaft and crankshaft wheels with their corresponding Hall sensors, throttle position and oil temperature sensors as well as the electronic management unit. When working on gasoline, the engine-generator set was able to provide up to 8 kW of continuous electric power (10 kW peak power), whereas working on hydrogen it provided up to 5 kW of electric power at an engine speed of 3000 rpm. The air-to-fuel equivalence ratio (λ) was adjusted to stoichiometric (λ = 1) for gasoline. In contrast, when using hydrogen the engine worked ultra-lean (λ = 3) in the absence of connected electric load and richer as the load increased. Comparisons of the fuel consumptions and pollutant emissions running on gasoline and hydrogen were performed at the same engine speed and electric loads between 1 and 5 kW. The specific fuel consumption was much lower with the engine running on hydrogen than on gasoline. At 5 kW of load up to 26% of thermal efficiency was reached with hydrogen whereas only 20% was achieved with the engine running on gasoline. Regarding the NOx emissions, they were low, of the order of 30 ppm for loads below 4 kW for the engine-generator set working on hydrogen. The bi-fuel engine is very reliable and the required modifications can be performed without excessive difficulties thus allowing taking advantage of the well-established existing fabrication processes of internal combustion engines looking to speed up the implementation of the energetic uses of hydrogen.
Open Access
The project book: a toolkit for stakeholder management in international development projects
(Universidad de Zaragoza, 2024-10-24) Romero de Miguel, Aida; Pérez Ezcurdia, Amaya; Gimena Ramos, Faustino; Ingeniería; Ingeniaritza; Sociología y Trabajo Social; Soziologia eta Gizarte Lana
En este artículo, se presenta una metodología de gestión de proyectos de cooperación internacional al desarrollo diseñada para agentes deslocalizados que, sobre una base tradicional de gestión de proyectos (fases y procesos), añade un sistema documental abierto (libro del proyecto) y la aplicación de técnicas de investigación-acción participativa. El libro del proyecto mejora la transparencia y, por tanto, la confianza y el compromiso. Con las técnicas de investigación-acción participativa, se apoya la gestión intercultural de los agentes de los proyectos. La metodología ha sido probada en tres sectores -«salud», «producción» y «educación»-, ejecutados en Colombia. La calidad y el éxito del proyecto tras su aplicación se caracteriza por una aceptación del 80 % de los agentes.
Open Access
The integration of mechanical energy absorbers into rollover protective structures to improve the safety of agricultural tractors in the event of rollover
(MDPI, 2024) Alfaro López, José Ramón; Pérez Ezcurdia, Amaya; Latorre Biel, Juan Ignacio; Arana Navarro, Ignacio; Benito Amurrio, Marta; Villanueva Roldán, Pedro; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1912
The combination of safety belts and rollover protective structures (ROPSs) is key in improving the safety of agricultural tractors in the event of rollover. However, we also have the opportunity to enhance the security provided by each ROPS; one such example is the combination of this safety device with adequate mechanical energy absorbers (MEAs). Inexpensive disc-shaped MEAs can be included in the anchoring points of a ROPS onto the chassis of a tractor. Three configurations of ROPS combined with MEAs were tested during the application of loads that simulated the effects of side rollover in the vehicle. The tested configurations included a blank MEA as a reference case alongside a single MEA and a stack assembly containing both elements. The results of the tests show that both the deformation of the ROPS itself and the strain energy are larger in the case of blank MEAs; thus, there is also a risk that the clearance zone will be infringed upon and that the protective structure will collapse. We can conclude that the implementation of an appropriate MEA in ROPS reduces the deformation of the ROPS itself and its strain energy in cases of vehicle rollover; hence, the safety provided by such protection systems may be improved at a low cost.
Open Access
Project risk management methodology for small firms
(Elsevier, 2014) Marcelino Sádaba, Sara; Pérez Ezcurdia, Amaya; Echeverría Lazcano, Amparo; Villanueva Roldán, Pedro; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería
Open Access
Influence of geometry in the behavior of disc-shaped mechanical energy absorbers for agricultural tractors
(MDPI, 2021-12-20) Latorre Biel, Juan Ignacio; Pérez Ezcurdia, Amaya; Benito Amurrio, Marta; Alfaro López, José Ramón; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1912
Disc-shaped mechanical energy absorbers (MEAs), in combination with rollover protection structures (ROPSs), may contribute to the prevention of the infringement of the safety zone and the collapse of the ROPS in case of the overturn of an agricultural tractor. An MEA can absorb a significant amount of potential energy of an overturning tractor and its deformation produces a rotation of the ROPS around the safety zone. In this research, MEAs with two different geometries have been developed. Both geometries present common features, such as disc dimensions, number of rings, and number of arms, but the distribution of the arms differs. Additionally, these MEA were manufactured in steel discs of four different thicknesses, ranging from 2 to 6 mm. The manufactured MEAs were tested in a universal testing machine, and their behavior characterized. From this data, linear models of the MEAs were developed. As a consequence, a number of characteristic parameters were selected and calculated, such as the activation load and the strain energy absorbed in a safe range of applied loads. Some patterns and trends were analyzed from the tested MEAs, which enables a better description of their behavior and the extrapolation of this behavior to other non-tested thicknesses and geometries.
Open Access
Development and tests of a neonatal portable foldable emergency incubator
(World Scientific, 2018-08-03) Ballesteros Egüés, Tomás; Arana Navarro, Ignacio; Pérez Ezcurdia, Amaya; Alfaro López, José Ramón; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
Open Access
Feasibility of vermicomposting of spent coffee grounds and silverskin from coffee industries: a laboratory study
(MDPI, 2020) González Moreno, Miguel Ángel; Marcelino Sádaba, Sara; Zaratiegui Urdin, Javier; Robles Domínguez, Estrella; Pérez Ezcurdia, Amaya; Seco Meneses, Andrés; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Gobierno de Navarra / Nafarroako Gobernua, VERMICOMPOSTAJE 4.0-VERMIOT (0011-1365-2019-000110)
In the coffee industry, several by-products are generated during the production and consumption of coffee and represent an important waste from an environmental viewpoint. For improving the knowledge about this issue, a laboratory vermicomposting study of coffee silverskin (CS) and spent coffee grounds (SCG) spiked with mature horse manure (HM) in different proportions and using earthwormEisenia andreiwas carried out. The 60-day study focused on biological parameters such as total biomass gain, growth rate, cocoon production, and mortality. This study also investigated whether the vermicompost obtained could be useful and lacked toxicity through a seed germination test using hybrid wheat seeds. Results showed a disparity depending on the type of residue and the mixture used. Best options were those treatments with a medium-low amount of residue; 25% for SCG and 25% or 50% for CS. In addition, lack of toxicity was confirmed in all treatments. In conclusion, it is possible to carry out a vermicomposting of SCG and CS with some specific features.
Open Access
Project management in development cooperation. Non-governmental organizations
(Universidad Nacional de Colombia, 2015) Montes Guerra, Maricela I.; Romero de Miguel, Aida; Pérez Ezcurdia, Amaya; Gimena Ramos, Faustino; Díez Silva, H. Mauricio; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Trabajo Social; Gizarte Lana
Este artículo analiza la adopción de prácticas propias de la gestión de proyectos en las ONG destinadas a la cooperación para el desarrollo, así como su influencia en la ejecución y el impacto de la aplicación de metodologías, técnicas y herramientas, en los resultados obtenidos por varios proyectos de reciente ejecución. Para tales efectos, se recolectó información de los directores de proyectos de las organizaciones seleccionadas, y adicionalmente se llevó a cabo una revisión de literatura sobre el tema. Con esta información se analizó la correlación entre las variables que determinan la adopción de un proyecto y los criterios que fijan el éxito en su ejecución, demostrando el efecto positivo de la adopción de este enfoque en la realización de proyectos de cooperación, a pesar de la escasa aplicación de las metodologías propuestas. El documento muestra la importancia de la gestión de proyectos en planes de cooperación y ayuda internacional, y tiene como objetivo incentivar el interés de los investigadores en el área dando a conocer los beneficios de su adopción en el sector. Por último, se demuestra que la aplicación de este enfoque también trae ventajas para el desarrollo de proyectos en otros sectores.