Predicting fuel energy consumption during earthworks

This research contributes to the assessment of on-site fuel consumption and the resulting carbon dioxide emissions due to earthworks-related processes in residential building projects, prior to the start of the construction phase. Several studies have been carried out on this subject, and have demonstrated the considerable environmental impact of earthworks activities in terms of fuel consumption. However, no methods have been proposed to estimate on-site fuel consumption during the planning stage. This paper presents a quantitative method to predict fuel consumption before the construction phase. The calculations were based on information contained in construction project documents and the definition of equipment load factors. Load factors were characterized for the typical equipment that is used in earthworks in residential building projects (excavators, loaders and compactors), taking into considering the type of soil, the type of surface and the duration of use. We also analyzed transport fuel consumption, because of its high impact in terms of pollution. The proposed method was then applied to a case study that illustrated its practical use and benefits. The predictive method can be used as an assessment tool for residential construction projects, to measure the environmental impact in terms of on-site fuel consumption. Consequently, it provides a significant basis for future methods to compare construction projects.Peer ReviewedPostprint (author's final draft

A Frame-Based System for Automatic Classification of Semi- Structured Data

The problem of data classification goes back to the definition oftaxonomies covering knowledge areas. With the advent of the Web, the amount of data available increased several orders of magnitude, making manual data classification impossible. This work presents a tool to automatically classify semi-structured data, represented by frames, without any previous knowledge about structured classes. The tool uses a variation of the K-Medoid algorithm and organizes a set of frames into classes, structured as a strict hierarchy

How reliable are Hanle measurements in metals in a three-terminal geometry?

We test the validity of Hanle measurements in three-terminal devices by using aluminum (Al) and gold (Au). The obtained Hanle and inverted Hanle-like curves show an anomalous behavior. First, we measure Hanle signals 8 orders of magnitude larger than those predicted by standard theory. Second, the temperature and voltage dependences of the signal do not match with the tunneling spin polarization of the ferromagnetic contact. Finally, the spin relaxation times obtained with this method are independent of the choice of the metallic channel. These results are not compatible with spin accumulation in the metal. Furthermore, a scaling of the Hanle signal with the interface resistance of the devices suggests that the measured signal is originated in the tunnel junction.Comment: 9 pages, 5 figure

The use of online dictionaries in second language learning (L2): teaching dictionary skills for advanced students.

This dissertation deals with the advantages and tools supplied by new technologies nowadays. More specifically, the study analyses the use of online dictionaries for the learning and the study of new languages (L2). It reports the results of a research on how advanced language learners use online dictionaries and to what extent they take advantage of all the resources those provide. The data was collected through questionnaires given to 3rd and 4th grade students of the degree in English Studies at the University of Zaragoza. The results revealed how they use online dictionaries and what they think about them, they showed that advanced students still underuse online dictionaries for pronunciation, phonetic and grammatical tasks, although online dictionaries provide a wide range of tools for helping learners in all kind of tasks such as reading or writing. Most of them only use them for translating a word or finding its meaning. For these reasons I proposed a dictionary workshop involving different skills for making students aware of the different possibilities online dictionaries provide

As metamorfoses do corpo, espacialidade e transcendência em Heidegger e Kafka

O artigo tem o propósito de problematizar a designação de “realismo fantástico” geralmenteatribuída ao estilo literário de Franz Kafka. Isto se faz de modo a questionar a presença docomponente fantástico na própria realidade, interrogando pelos pressupostos fundamentais em jogona composição de realidade e fantasia. O presente problema, e outros que dele derivam, pretendeser respondido não apenas diante da consideração dos escritos do autor tcheco, especialmente noconto A Metamorfose, mas na interface da filosofia de Martin Heidegger. O filósofo alemão nosoferece, em sua obra Ser e tempo, elementos para darmos os seguintes passos: delimitar o lugar dohomem a partir da constituição singular do espaço de transcendência que o mundo é; considerar asexperiências de singularidade e aversão em face da noção de poder-ser; abordar as assim chamadas“metamorfoses do corpo” e como tais transformações físicas do personagem impõem-lheconcomitantemente uma mudança do seu próprio modo de ser

Evaluacion de la metodologia de estudio de eventos en el mercado de capitales chilenos.

251 p.Considerando que el poder de la metodología de Estudio de Eventos ha sido escasamente validado para el caso de mercado de capitales emergentes, en el presente trabajo utilizamos el enfoque de simulación sugerido por Brown y Wagner (1980, 1985) con el fan de evaluar el poder de dicha metodología en el mercado de capitales chileno. Analizando 18 muestras obtenidas de la Bolsa de Comercio de Santiago, los resultados sugieren que a pesar de la escasa profundidad que exhibe el mercado de capitales domestico, los modelos de Media Constante y de Ajuste al Mercado muestran un desempeño razonable en la detección de retornos anormales. Para un nivel de significancia del 5% ambos modelos detectan retornos anormales de un 1% y un 5% diario en el 65% y en el 100% de los casos, respectivamente

Feasibility study of a Solar Electric Propulsion mission to Mars

Traditionally, space missions to outer planets have relied on large amounts of chemical propellant or flybys to achieve their objectives. This large mass consumption may be significantly reduced using electric propulsion (EP), since it allows for larger specific impulses. However, this improvement is counteracted by the lower thrust per power levels achievable with EP engines compared to chemical thrusters. Here we discuss how to find a balance for a purely solar EP (SEP) uncrewed mission to Mars. We present system engineering and mission analyses focused on the orbital mechanics. The result is the conceptual design of a realistic mission to Mars, in which any target orbit around Mars can be reached using solely present SEP technology. In particular, for a 2000 kg spacecraft propelled with a Hall effect thruster (HET), the interplanetary transfer can be performed in 363 days with less than 400 kg of fuel consumption, provided that the vehicle leaves the Earth orbit with a suitable specific energy that is attainable using current launchers. Subsequently, 300 kg of propellant are sufficient to allow for the planetary capture, plane change, and circularisation manoeuvres, finally inserting the spacecraft into a polar orbit of height between 300 km and 1000 km above the surface of Mars.Agencia Estatal de Investigación | Ref. PID2020-118613GB-I00Xunta de Galicia | Ref. ED431B 2021/22Ministerio de Universidades | Ref. CAS21/00502Universidade de Vigo/CISU