Wind risk assessment in urban environments: the case of falling trees during windstorm events in Lisbon

Trees bring many benefits to the urban environment. However, they may also cause hazards to human population, being the major causes of injuries and infrastructural damage during strong wind events. In the city of Lisbon, strong winds rather frequently result in tree falls, depending on the season and meteorological conditions. This paper presents a methodology to analyse tree damage due to strong wind events in urban environments. Each occurrence has been recorded by the Lisbon Fire Brigade and Rescue Services (Regimento de Sapadores Bombeiros de Lisboa - RSBL). Information provided by RSBL relating to the period of 1990-2005 was considered along with hourly wind speed and direction, species, fitossanitary conditions and urban parameters. To ensure that the fallen trees were caused by strong winds, only days with three or more occurrences of fallen trees were selected. It was found that in summer, northerly winds are responsible for 11% of tree falls, with winds from other directions (west, southwest and south) responsible for 5%. From autumn to spring, perturbed weather conditions originating from the west, southwest and south are responsible for 84% of fallen trees. The majority of tree falls occurred when wind speed surpassed 7 m/s in the six hours prior to their fall. Some recommendations to the Civil Protection Agency and the Fire Department are presented to improve the mission of collecting information. This research is a contribution to the assessment of wind risk in Lisbon

Analytical approach to directed sandpile models on the Apollonian network

We investigate a set of directed sandpile models on the Apollonian network, which are inspired on the work by Dhar and Ramaswamy (PRL \textbf{63}, 1659 (1989)) for Euclidian lattices. They are characterized by a single parameter $q$, that restricts the number of neighbors receiving grains from a toppling node. Due to the geometry of the network, two and three point correlation functions are amenable to exact treatment, leading to analytical results for the avalanche distributions in the limit of an infinite system, for $q=1,2$. The exact recurrence expressions for the correlation functions are numerically iterated to obtain results for finite size systems, when larger values of $q$ are considered. Finally, a detailed description of the local flux properties is provided by a multifractal scaling analysis.Comment: 7 pages in two-column format, 10 illustrations, 5 figure

Numerical methods to predict vibration serviceability on high frequency stairs

With the increasingly deepen knowledge on structural dynamic behaviour, nowadays, monumental staircases and their steps are usually designed with high stiffness and low mass, obtaining high fundamental frequencies, out of the interval of step frequencies excitable by the human walking. However, neglecting the structure's mass can also result in with high levels of impulsive responses. Furthermore, often the connection between the staircase and its steps experience an almost null rotational stiffness, which can cause local vibrations in steps, where the structural behaviour of two elements is nearly independent from each other. In this scenario, steps will most likely exhibit undesirable vibrations. Hence, intending to improve future designs, this paper compares different numerical methods that can be used to predict human induced vibrations in this type of structures, applying them to a real staircase with a high local liveness. The results showed that the footfall force time histories method could realistically predict the vibrations for almost all tested step frequencies, while the effective impulse could accurately estimate the vibrations for descents at different step frequencies. The walking models defined by Fourier coefficients only generated close vibrations for descents at 3.3 Hz.info:eu-repo/semantics/publishedVersio

Human Mobility in Large Cities as a Proxy for Crime

We investigate at the subscale of the neighborhoods of a highly populated city the incidence of property crimes in terms of both the resident and the floating population. Our results show that a relevant allometric relation could only be observed between property crimes and floating population. More precisely, the evidence of a superlinear behavior indicates that a disproportional number of property crimes occurs in regions where an increased flow of people takes place in the city. For comparison, we also found that the number of crimes of peace disturbance only correlates well, and in a superlinear fashion too, with the resident population. Our study raises the interesting possibility that the superlinearity observed in previous studies [Bettencourt et al., Proc. Natl. Acad. Sci. USA 104, 7301 (2007) and Melo et al., Sci. Rep. 4, 6239 (2014)] for homicides versus population at the city scale could have its origin in the fact that the floating population, and not the resident one, should be taken as the relevant variable determining the intrinsic microdynamical behavior of the system.Comment: 17 pages, 8 Figure

Intelligent event broker: a complex event processing system in big data contexts

In Big Data contexts, many batch and streaming oriented technologies have emerged to deal with the high valuable sources of events, such as Internet of Things (IoT) platforms, the Web, several types of databases, among others. The huge amount of heterogeneous data being constantly generated by a world of interconnected things and the need for (semi)-automated decision-making processes through Complex Event Processing (CEP) and Machine Learning (ML) have raised the need for innovative architectures capable of processing events in a streamlined, scalable, analytical, and integrated way. This paper presents the Intelligent Event Broker, a CEP system built upon flexible and scalable Big Data techniques and technologies, highlighting its system architecture, software packages, and classes. A demonstration case in Bosch’s Industry 4.0 context is presented, detailing how the system can be used to manage and improve the quality of the manufacturing process, showing its usefulness for solving real-world event-oriented problems.This work has been supported by FCT –Fundação para a Ciência e Tecnologiawithin the Project Scope: UID/CEC/00319/2019 and the Doctoral scholarship PD/BDE/135101/2017. This paper uses icons made by Freepik, from www.flaticon.com

Specific electrical energy consumption and CO2 emissions assessment of agrifood industries in the central region of Portugal

This paper provides a characterization of the electrical energy consumption of agrifood industries located in the central region of Portugal that use refrigeration systems to ensure the food safety. The study is based on the result analysis of survey data and energy characteristics of the participating companies belonging to the following agrifood sectors: meat, dairy, horticultural, distribution and wine. Through the quantification of energy consumption of companies is possible to determine the amount of greenhouse gases (GHGs) emissions indexed to its manufacturing process. Comparing the energy and GHGs emissions indexes of companies of a sector and between sectors is possible to create reference levels. With the results of this work is possible to rating the companies in relation to reference levels of energy and GHGs emissions and thus promote the rational use of energy by the application of practice measures for the improvement of the energy efficiency and the reduction of GHGs emissions.info:eu-repo/semantics/publishedVersio

The characterization of the specific energy consumption of electricity in the Portuguese sausage industry

The sausage is an ancient food type that is nowadays considered as a delicatessen. Sausages are categorized within the deli sector as meat sub products. It is a food product preferred by consumers due to its nutritional value and organoleptic characteristics (wide range of flavours and textures). There are many types of sausages, with around 1200 different varieties (according to German classification), classified into types according to different criteria such as types of ingredients, consistency, and preparation (raw, cooked, pre-cooked, dry). In the UK, 196,152 metric tons of sausages were consumed during 2011, valued in $1.2 billion, while in the US this value was around$20.4 billion two years before. The heating and cooling processes during sausage production are indispensable technologies to ensure both the specific organoleptic characteristics and properties conservation through time. This paper characterizes the production process and the energy consumption of sausages processing industry in Portugal (20 industries) and discusses the average specific energy consumption (SEC) of electricity and its standard deviation. The average value of this indicator for the sample was 660 kWhe/ton raw material. The energy consumption of this type of industry is mainly that of electricity (82%). Several electricity savings, estimated at 23.9%, can be achieved by implementing simple practice measures in the refrigeration systems.info:eu-repo/semantics/publishedVersio

Characterization of the specific electrical energy consumption of agrifood industries in the central region of Portugal

This paper provides a characterization of the electrical energy consumption of agrifood industries located in the central region of Portugal that use refrigeration systems to ensure the food safety. The study is based on the result analysis of survey data and energy characteristics of the participating companies. The agrifood industries included in the survey belong to the following sector: meat, dairy, horticultural, distribution and wine. The comparison of energy indicators for the specific electrical energy consumption of companies of a sector and between sectors is analysed and discussed, providing reference levels for the energy performance of agrifood industries. Since the agrifood sector accounts for high level of energy consumption, the energy performance level knowledge can promote the rational use of energy as well as helping on the decision making of practice measures for the improvement of the energy efficiency.info:eu-repo/semantics/publishedVersio