A model proposal for the electric energy valorization in a pv power plant equipped with CAES system

In this article, an analytical method is evaluated and implemented; to assess the possible electricity sales strate-gies produced by a 3 MW photovoltaic power plant, connected to a 250 kW CAES (Compressed Air Energy Storage) system, with a storage capacity of 750 kWh. The presented model combines a different numbers of parameters and variables, relevant for the system optimization. Several simulations of various system configu-rations have been carried out, to explore and evaluate the economic and technical feasibility of the plant, spe-cifically it has been valued tow case of study: CASE 1 the system is not incentive; CASE 2 the system is incen-tive. In the end of paper it has been rated the Leveled Cost of Energy (LCOE) and specified how the investment could become affordable in the foreseeable future

Green practices and financial performance: A global outlook

Companies around the world adopt green practices with the aim to reduce their environmental impacts and improve their financial performance. The present study theorizes about and empirically examines the impacts of corporate green practices on financial performance. Indexes of pollution prevention, green supply management, green product development and ISO 14001 adoption are obtained for each firm in a panel of 3490 publicly-traded companies from 58 countries over 13 years. Results show that internal green practices (pollution prevention and green supply chain management) are the major environmental drivers of financial performance, while external green practices (green product development) play a secondary role in determining financial performance. The adoption of ISO 14001 appears to have a negative impact on financial performance. This study provides empirical support for policy-makers promoting environmental practices that may lead to sustainable economic growth

Solar radiation forecasting, accounting for daily variability

Radiation forecast accounting for daily and instantaneous variability was pursued by means of a new bi-parametric statistical model that builds on a model previously proposed by the same authors. The statistical model is developed with direct reference to the Liu-Jordan clear sky theoretical expression but is not bound by a specific clear sky model; it accounts separately for the mean daily variability and for the variation of solar irradiance during the day by means of two corrective parameters. This new proposal allows for a better understanding of the physical phenomena and improves the effectiveness of statistical characterization and subsequent simulation of the introduced parameters to generate a synthetic solar irradiance time series. Furthermore, the analysis of the experimental distributions of the two parameters’ data was developed, obtaining opportune fittings by means of parametric analytical distributions or mixtures of more than one distribution. Finally, the model was further improved toward the inclusion of weather prediction information in the solar irradiance forecasting stage, from the perspective of overcoming the limitations of purely statistical approaches and implementing a new tool in the frame of solar irradiance prediction accounting for weather predictions over different time horizons

Study of an emergency situation using 2D and 3D simulation models

Safety in motorway tunnels has become a critical issue in the last years, especially after the accident happened in 1999 inside the Mont Blanc tunnel, causing 39 deaths and several dozens of intoxications and wounded people. After this tragic event, the European Union imposed stricter regulations and procedures for emergency situations inside road tunnels longer than 1000 m. According to this situation, the authors propose the use of M&S (Modeling and Simulation) in order to manage a tunnel evacuation after a fire exploding in consequence to an accident, taking into account a series of significant factors like the road signs position (new criteria have been introduced with new regulation), but also human factors which significantly affect the procedure outcome. First a 2-D simulation model has been developed using Java™ Software, in which the user can analyze the behavior of the people escaping and the dynamics of the fire exploded and, consequently, assess the effectiveness of all the emergency procedures and infrastructures. In particular, regarding the state variables related to the human behavior, the model takes into account the main aspects of PECS (Physical Emotional Cognitive Social) reference models, in which physical, emotional, cognitive and social factors have to be studied. The model presented in this work is in fact quite similar to the one described by (Schmidt, 2000), called “Adam’s World” where Adam, a primitive man, lives in an environment having food sources where he can replenish his energy level, but also traps and danger points to be avoided in order not to consume his energy faster. The aim of the two models is the same: first of all preserve life and health, but the great difference between Schmidt’s model and the authors’ one is that in Adam’s World the social aspect is missing (Adam live alone in his world), while in the evacuation model social aspects can significantly affect the individual’s decisions. Upstream of the evacuation model, a weighted analysis needs to be considered, in fact the individual has to operate different choices considering several aspects, like health or goods preservation, familiar aspects, panic and so on. For this reason a suitable methodology has been detected: the Analytic Hierarchic Process (AHP), implemented by the American mathematician Thomas Saaty, which introduced this technique for Multi-Criteria Analysis. After the considerations on the individuals behavior based on the results of the analysis, the evacuation model and its results are described and analyzed in the following sections and, in the final part of the paper, a description of a 3-D tunnel model devoted to study in particular smoke dynamics is provided, thus it is possible to evaluate the impact of the smoke on the flow of the people escaping from the tunnel

Semi-supervised detection of structural damage using Variational Autoencoder and a One-Class Support Vector Machine

In recent years, Artificial Neural Networks (ANNs) have been introduced in Structural Health Monitoring (SHM) systems. A semi-supervised method with a data-driven approach allows the ANN training on data acquired from an undamaged structural condition to detect structural damages. In standard approaches, after the training stage, a decision rule is manually defined to detect anomalous data. However, this process could be made automatic using machine learning methods, whom performances are maximised using hyperparameter optimization techniques. The paper proposes a semi-supervised method with a data-driven approach to detect structural anomalies. The methodology consists of: (i) a Variational Autoencoder (VAE) to approximate undamaged data distribution and (ii) a One-Class Support Vector Machine (OC-SVM) to discriminate different health conditions using damage sensitive features extracted from VAE's signal reconstruction. The method is applied to a scale steel structure that was tested in nine damage's scenarios by IASC-ASCE Structural Health Monitoring Task Group

Delayed recurrent nerve paralysis following post-traumatic aortic pseudoaneurysm

Blunt trauma to the neck or to the chest are increasingly observed in the emergency clinical practice. They usually follow motor vehicle accidents or may be work or sports related. A wide pattern of clinical presentation can be potentially encountered. We report the uncommon case of a patient who was referred to our observation presenting with hoarseness and disphagia. Twenty days before he had sustained a car accident with trauma to the chest, neck and the mandible. Laryngoscopy showed a left recurrent laryngeal nerve palsy. Further otolaryngo-logical examination showed no other abnormality. At CT and MR imaging a post-traumatic aortic pseudoaneurysm was revealed. The aortic pseudoaneurysm was consequently repaired by implantation of an endovascular stent graft under local anesthesia. The patient was discharged 10 days later. At 30-days follow-up laryngoscopy the left vocal cord palsy was completely resolved. Hoarseness associated with a dilated left atrium in a patient with mitral valve stenosis was initially described by Ortner more than a century ago. Since then several non malignant, cardiovascular, intrathoracic disease that results in embarrassment from recurrent laryngeal nerve palsy usually by stretching, pulling or compression; thus, the correlations of these pathologies was termed as cardiovocal syndrome or Ortner's syndrome. The reported case illustrates that life-threatening cardiovascular comorbidities can cause hoarseness and that an impaired recurrent laryngeal nerve might be correctable

An extensive questionnaire about Metacognition during Emergency Remote Teaching involving more than 3000 engineering students

By 11 March 2020, the phrase “COVID-19” had officially entered everyday life across most of the word. Each level of education suddenly faced new changes and new challenges. Emergency remote teaching became widespread, and new methodologies to deliver classes and courses were adopted by educational institutions. In this paper, we focus on the impact of the remote learning experience of engineering students enrolled at the Politecnico di Milano. The subjects were recruited from all engineering courses from the first to the fifth year and were asked to complete a multidimensional survey. The survey featured 66 items regarding the participants’ perceptions of the challenges of emergency remote teaching compared with pre-COVID-19 in-person teaching. The questionnaire addressed six dimensions: the organization of emergency remote teaching, subjective well-being, metacognition, self-efficacy, identity, and socio-demographic information. In this paper, we describe the entire survey and discuss a preliminary analysis. Using Cronbach’s alpha test, a confirmatory factor analysis, and the t-test, we performed a more in-depth analysis concerning the outcomes of metacognition and self-efficacy. The data analysis suggested a small, unexpected change in the metacognition strategies. The students, in some regards, improved their learning strategies. Some other answers underlined their appreciation of the courses’ organization and the lack of relationships with their peers and teachers