Risk management in solar-based power plants with storage: a comparative study

Investment in solar generation is essential to achieve EU climate neutrality by 2050. Using stochastic programming, we study the management of solar power plants considering trading in the spot and future markets, weather derivatives based on solar radiation, storage, and risk management. We provide a comparative study of two technologies: a concentrated solar power plant with thermal storage and a photovoltaic power plant with electrical batteries. The significant managerial contributions can be classified into four levels. First, regarding trading and generation decisions, we proved that: a) plants sell energy in the spot market during the night and store energy in the morning; b) storage happens at the same time as electricity is purchased in the spot market; c) in the Summer the plants sell more in the futures market; d) storage, in both types of technology, increases trading in futures and spot markets and creates value for generators. Second, regarding the use of options on solar radiation, we show that a) the value of put and call options depends on the expected solar radiation; b) the radiation option prices are correlated with generation and storage levels and with the anticipated trading in spot and futures markets; c) the optimal strategy is to sell calls and buy put options; d) generators with a storage system sell significantly more call options. Third, regarding risk aversion, we proved that: a) the higher the risk aversion, the more the generator sells in the futures market and the higher the number of purchased put contracts; b) the risk-adjusted profit from options trading is zero. Finally, in comparing both technologies, even though the operation and financial management patterns are similar, the photovoltaic power plant is more profitable, and the batteries create more value

An integrated decision support system for improving wildfire suppression management

Funding Information: This work was financially supported by FCT (National Foundation of Science and Technology) within the Research Unit CTS?Centre of Technology and Systems, UIDB/00066/2020, and the Project forester (PCIF/SSI/0102/2017). We would like to thank the authorities from the municipality of Ma??o, in particular to Engineer Ant?nio Louro, for the valuable support in establishing the user requirements and the feedback for the system?s validation. Special thanks to the Adjunct of National Operations in the National Command of Security Operations (CNOS) part of the National Authority of Civil Protection (ANPC) Alexandre Penha, for their input in the early stages of this work.Wildfires are expected to increase in number, extent, and severity due to climate change. Hence, it is ever more important to integrate technological developments and scientific knowledge into fire management aiming at protecting lives, infrastructure, and the environment. In this paper, a decision support system (DSS) adapted to the Portuguese context and based on multi-sensor technologies and geographic information system (GIS) functionalities is proposed to leverage operational data, enabling faster and more informed decisions to reduce the impact of wildfires. Here we present a flexible and reconfigurable DSS composed of three components: an ArcGIS online feature service that provides operational data and enables a collaborative environment of users that share operational data in near real-time; a mobile client application to interact with the system, enabling the use of GIS technology and visualization dashboards; and a multi-sensor device that collects field data providing value to external services. The design and validation of this system benefitted from the feedback of wildfire management specialists and a partnership with an end-user in the municipality of Mação that also helped establish the system requirements. The validation results demonstrated that a robust system was achieved with fully interoperable components that fulfill the defined system requirements.publishersversionpublishe

ENVIRONMENTAL EXERGY ANALYSIS OF WASTEWATER TREATMENT PLANTS

This work evaluates the environmental impact of Wastewater Treatment Plants (WTP) based on data generated by the exergy analysis, calculating and applying environmental impact indexes for two WTP located in the Metropolitan Area of São Paulo. The environmental impact of the waste water treatment plants was done by means of evaluating two environmental impact exergy based indexes: the environmental exergy efficiency (ηenv,exerg) and the total pollution rate (Rpol,t). The environmental exergy efficiency is defined as the ratio of the exergy of the useful effect of the WTP to the total exergy consumed by human and natural resources, including all the exergy inputs. That relation is an indication of the theoretical potential of future improvements of the process. Besides the environmental exergy efficiency, it is also used the total pollution rate, based on the definition done by Makarytchev (1997), as the ratio of the destroyed exergy associated to the process wastes to the exergy of the useful effect of the process. The analysis of the results shows that this method can be used to quantify and also optimise the environmental performance of Wastewater Treatment Plants

Explicit method in the seismic assessment of unreinforced masonry buildings through plane stress elements

The complex nonlinear behaviour of unreinforced masonry (URM), along with the interaction between structural elements, still represents a challenge for the seismic assessment of existing URM buildings. A large variety of mathematical tools have been developed in the last decades to address the issue. The numerical work herein presented attempts to provide some insights into the use of FEM models to obtain reliable results from nonlinear dynamic analyses conducted with explicit methods. Through plane stress elements, two in-plane mechanisms were studied to identify optimal parameters for unreinforced masonry elements subjected to dynamic actions. The results were then compared with outcomes generated by an implicit solver. Subsequently, these parameters were used in nonlinear dynamic analyses on a building section for the seismic assessment in both unreinforced and reinforced conditions. The element type, hourglass control, damping, and bulk viscosity influence the dynamic response, mainly when the nonlinearities become larger. The hourglass control techniques employ a scaling factor to suppress the occurrence of spurious modes. Values ranging from 0.01 to 0.03 have shown effective results. When the stiffness-damping parameter for Rayleigh damping is of a similar order of magnitude or lower than the time increment without damping, the time increment remained in feasible ranges for performing analysis. Additionally, the bulk viscosity can stabilise the response without causing substantial alterations to the time increment if the values are under 1.00.This work was funded by FCT—Foundation for Science and Technology within the scope of project EXPL/ECI-EGC/0940/2021. The first author is grateful for the funding from the Mexican National Council for Science and Technology (Consejo Nacional de Ciencia y Tecnología CONACYT), grant number 2018-000013-01EXTF-0013

Manipulação dos Resultados por Empresas em Dificuldades Financeiras: Estudo para um Caso Português.

Ciências EmpresariaisMaster Programme in Management Science

Controlling diarrheagenic E. coli with bacteriophages: facts and challenges

Enterotoxigenic Escherichia coli (ETEC) colonizes the intestine, causing severe diarrhoea in humans and animals. The rise of antibiotic resistances and limitation on their use demands news strategies to tackle this pathology. Bacteriophages (phages), viruses specifically infecting bacteria and harmless to animals and plants, are a promising antibacterial tool. Although studies support their ability to efficiently overcome ETEC infections, they have been shown to be highly strain-specific. If this can be associated with the presence of anti-phage defense systems (APDS) in ETEC genomes, it is also true that phages can counter-evolve to escape APDS. This work aimed to define phage cocktail with broader lytic spectra, capable of overcoming APDS of ETEC, enhancing phage efficacy. We firstly sequenced 29 ETEC strains from our collection to search for the presence of APDS in their genomes. Then, we performed phage isolation and the subsequent in vitro and genomic characterization: i) evaluation of lytic spectra against ETEC collection; ii) whole-genome sequencing and phage safety evaluation (absence of undesirable genes) iii)presence of proteins responsible for escaping the main APDS. We were able to identify distinct mechanisms supporting APDS. Bacterial proteins that prevent the entry of DNA from phages (CRISPR-Cas-related proteins) or that enable the cut of phage nucleic acids (restriction-modification enzymes) were detected, however, most of them were related with the induction of abortive infection events (e.g. toxin-antitoxin systems). We also isolated 3 phages, SUS35, SUS42 and SUS65, which proved to be safe for therapy and to encode proteins enabling to escape APDS, inclusively against abortive infection. Phage-host interaction mechanisms must be considered when preparing phage- based products for therapy. This work clearly indicates that a strict selection of phages, or the construction of synthetic phages with desired traits will be a turning point in their versatility to fight against ETEC infections.info:eu-repo/semantics/publishedVersio

Critical success factors during the implementation of ISO 22000:2018

Purpose: The purpose of the paper is to evaluate why companies still struggle with ISO 22000 implementation and maintenance, identifying which aspects are key for its success. Design/methodology/approach - A literature review was carried out based on Scientific articles and implementation guides collected from Google Scholar, ScienceDirect and ResearchGate. Findings - Nine aspects seem to have a broader impact on organizations maintenance of ISO 22000 and other FSMS. Furthermore, the empirical research reveals that having an efficient food safety management system is a prerequisite for companys competitiveness. Practical implications - The findings show that many of the critical success factors for a FSMS implementation are based on regular and adequate management of people inside the company. Originality/value - A novel model of segmenting critical success factors is presented, which has practical implications for ISO 22000 achievement.(undefined)info:eu-repo/semantics/publishedVersio

Studies on the interaction of three lytic bacteriophages with a wide collection of Escherichia coli strains implicated in swine enteric colibacillosis

bioRxiv - the Preprint Server for BiologyThe misuse of antibiotics in the swine industry and their on-going restriction requires alternatives to control enterotoxigenic and shiga toxin-producing Escherichia coli (ETEC and STEC, respectively). This study evaluates the potential of three coliphages, vB_EcoM_FJ1, vB_EcoM_FN and vB_EcoM_SP1 against 104 ETEC, STEC and ETEC/STEC strains isolated from pig colibacillosis in Portuguese (2018-2020) and Spanish farms (2006-2016), encompassing 71.2% mcr-positive strains (33.7% with mcr-1, 1.9% mcr-2, 35.6% mcr-4 and 2.9% mcr-5) and 18.3% positive strains for TEM (1%), SHV (6.7%), and CTX-M (11.5%) extended-spectrum beta-lactamase-encoding genes. In general, all bacteriophages presented a narrow lytic spectrum (up to 2.9%) against the 104 ETEC, STEC and ETEC/STEC. Bacteriophages shared >80% overall nucleotide identity with E. coli phage T4 (Tevenvirinae subfamily), but a particular look at the distal part of the long tail fiber (gp38) revealed no homology. All bacteriophages recognize lipopolysaccharides as receptors, and additionally, FN binds to an outer membrane protein A. Bacteriophage-insensitive mutants of vB_EcoM_FJ1 (90%) and vB_EcoM_FN (100%) were shown to be more susceptible to pig serum inactivation comparatively to the parental strain and furthermore, their adhesion capacity to porcine intestinal cells was diminished by, approximately, 90%. Contrariwise, vB_EcoM_SP1 insensitive variants did not display phenotypic differences comparing to the wild-type strain. This study demonstrates that besides being T4-like, these bacteriophages revealed a narrow lytic spectrum against diarrhoeagenic E. coli strains and that the acquisition of novel bacteriophage-encoded adhesins (gp38) seems to be determinant for such results.info:eu-repo/semantics/publishedVersio

Jóvenes Mexicanos em Medio de la Crisis Económica:: Los Problemas de la Integración Laboral

El artículo analiza el impacto de la crisis financiera global sobre el mercado laboral mexicano, centrando su interés en el estudio de las formas de participación de la mano de obra más joven en el mercado de trabajo. En concreto se estudia cómo la crisis acentuó, de manera diferencial, la mayor vulnerabilidad laboral de las y los trabajadores adolescentes, al fomentar procesos de informalización, precarización y desprotección laboral más intensos. Adicionalmente, se observa que la crisis tuvo impactos diferenciales a nivel regional, siendo que las entidades federativas con mayor integración a la economía norteamericana -como las de norte del país- fueron las más afectadas por esta crisis, en contraste con aquellas que presentan un bajo nivel de integración a los procesos de globalización económica en general y a la economía de los EEUU en particular -como las de la región sur del país. Finalmente, se observa que esta crisis también afectó, principalmente, a las entidades federativas que tenían mercados laborales más modernos, es decir, aquellas en los que predominan tasas altas de asalarización de las relaciones laborales