Forecasting day-ahead electricity prices in Europe: the importance of considering market integration

Motivated by the increasing integration among electricity markets, in this paper we propose two different methods to incorporate market integration in electricity price forecasting and to improve the predictive performance. First, we propose a deep neural network that considers features from connected markets to improve the predictive accuracy in a local market. To measure the importance of these features, we propose a novel feature selection algorithm that, by using Bayesian optimization and functional analysis of variance, evaluates the effect of the features on the algorithm performance. In addition, using market integration, we propose a second model that, by simultaneously predicting prices from two markets, improves the forecasting accuracy even further. As a case study, we consider the electricity market in Belgium and the improvements in forecasting accuracy when using various French electricity features. We show that the two proposed models lead to improvements that are statistically significant. Particularly, due to market integration, the predictive accuracy is improved from 15.7% to 12.5% sMAPE (symmetric mean absolute percentage error). In addition, we show that the proposed feature selection algorithm is able to perform a correct assessment, i.e. to discard the irrelevant features

Influence of concrete composition on chloride ingress and carbonation : analysis by means of an extended data-set

In 2015 an IWT-TETRA project, called DurOBet, was initiated focusing on service life design assessment according to different chloride diffusion and carbonation models applied on Belgian concrete mixtures. The main purpose of this research project is to develop a quantitative method for a service-life based design of concrete structures, more particular applicable for the Belgian concrete industry. In this way an improvement of the deemed-to-satisfy approach of the EN206-1 code can be established which is more reliable with regards to service life predictions of concrete structures. In the framework of this DurOBet project it was decided to develop an extensive database incorporating concrete related results on i) fresh properties, ii) hardened properties and iii) durability related properties such as porosity, permeability and more specifically on chloride ingress and carbonation. The data originate from numerous journal articles and conference papers, doctoral research projects and master thesis studies. At this time more than 100 papers or studies were investigated, reported between 1992 and 2016, generating a dataset of over a thousand unique concrete recipes, geographically spread but with focus on the concrete mixes applicable for the Belgian industry. Both traditional and self-compacting concrete mixes are incorporated into the database. This database is being used for the analysis of the durability related properties, such as the chloride diffusion and carbonation coefficient, and their relation with mix proportioning parameters of the concrete mixtures (cement or binder content, type of binder, water-to-binder ratio,…). The main focus of this paper is to highlight the framework of the database: the mix proportioning of the concrete mixes is being discussed and the origin of the concrete data (country, reference info, etc.). By means of data mining and some known relations with respect to the durability related properties, e.g. correlation between w/b-ratio and chloride diffusion coefficient, are being evaluated

Evaluation of the migration coefficient, diffusion coefficient and the ageing factor according to the chloride ingress model described in the fib bulletin 34 applied to Belgian concrete mixtures

In this contribution the chloride diffusion model according to fib bulletin 34 is applied and evaluated on Belgian concrete [1]. The service life estimation according to chloride-induced corrosion is, inter alia, affected by the chloride migration coefficient or chloride diffusion coefficient. In addition, the time dependency of these parameters, reflected in the ageing exponent, has an even greater influence on the model. In a first part the different diffusion coefficients will be discussed. In a second part the parameters are calibrated to the Belgian concrete compositions. The chloride migration coefficient and chloride diffusion coefficient depend on the type of cement and vary according to different types of cement and w/c ratios. The ageing exponent is also dependent on the exposure class. Such a calibration is performed on the most commonly used types of cement in Belgium, which are Portland cement (CEM I) and blended cements (CEM III/A and CEM III/B). Distributions are proposed and evaluated based on available Belgian data and results from laboratory experiments. Finally the time dependency of the instantaneous diffusion coefficients and the time dependency of the apparent diffusivities are investigated

Studies on the evolution of alkali silicate in a simulated alkali-silica reaction system

In this study, the interaction between the reactive silica present in aggregates and the alkalis and hydroxyls present in the pore solution of cement paste is simulated in a chemical model system and investigated experimentally. Various properties of the solid and liquid phases are investigated. The results show that the nano and micro structure and properties of the formed alkali silicate change significantly during this process

Numerical modelling of the filling of formworks with self-compacting concrete

This paper describes the numerical modelling of the flow of self-compacting concrete (SCC) in column and wall formworks during the filling process. It is subdivided in four main parts. In the first part, the rheological properties of SCC and the theory regarding the pressure exerted by the SCC on the formworks are shortly described. In the second part, the formwork filling tests, that have been carried out at the Magnel Laboratory for Concrete Research of the Ghent University, are presented. The general layout of the tests and the measurement set-up are clearly described. In the third part, the numerical modelling of the flow of SCC using a commercially available solver is explained as well as the obtained results from the CFD simulations. Finally in the last part, a comparison is made between the measurements and the simulation results. The formwork pressures are hydrostatic for SCC pumped from the base of the formworks

Thermic dehorning and ear tagging as atypical portals of entry of Clostridium tetani in ruminants

This paper describes two infections with Clostridium tetani (C. tetani). One outbreak occurred after dehorning of calves, the second infection happened after ear tagging of a goat. In the first case 3 young Holstein Friesian calves showed generalized stiffness, severe lock-jaw and bloat two weeks after dehorning. The thermal dehorning wounds were identified as the infection sites of C. tetani by bacterial culture and PCR. The second case was a three-year old male castrated goat, with generalized stiffness. The animal had been ear tagged one week prior to the onset of the symptoms. C. tetani could be cultured from pus on the ear tag. Treatment was attempted in two calves and the goat. Wounds were debrided and disinfected, penicillin and anti-tetanus serum were administered and polyionic perfusions provided. In addition, the goat was vaccinated against tetanus. The goat and one calf fully recovered after 36 and 8 days respectively. To the authors' knowledge a tetanus outbreak in association with thermal dehorning has not been described previously. Also ear tagging as a possible cause for C. tetani infection has not been described in goats