Operating Hydrogen-Based Energy Storage Systems in Wind Farms for Smooth Power Injection: A Penalty Fees Aware Model Predictive Control

Smooth power injection is one of the possible services that modern wind farms could provide in the not-so-far future, for which energy storage is required. Indeed, this is one among the three possible operations identified by the International Energy Agency (IEA)-Hydrogen Implementing Agreement (HIA) within the Task 24 final report, that may promote their integration into the main grid, in particular when paired to hydrogen-based energy storages. In general, energy storage can mitigate the inherent unpredictability of wind generation, providing that they are deployed with appropriate control algorithms. On the contrary, in the case of no storage, wind farm operations would be strongly affected, as well as their economic performances since the penalty fees wind farm owners/operators incur in case of mismatches between the contracted power and that actually delivered. This paper proposes a Model Predictive Control (MPC) algorithm that operates a Hydrogen-based Energy Storage System (HESS), consisting of one electrolyzer, one fuel cell and one tank, paired to a wind farm committed to smooth power injection into the grid. The MPC relies on Mixed-Logic Dynamic (MLD) models of the electrolyzer and the fuel cell in order to leverage their advanced features and handles appropriate cost functions in order to account for the operating costs, the potential value of hydrogen as a fuel and the penalty fee mechanism that may negatively affect the expected profits generated by the injection of smooth power. Numerical simulations are conducted by considering wind generation profiles from a real wind farm in the center-south of Italy and spot prices according to the corresponding market zone. The results show the impact of each cost term on the performances of the controller and how they can be effectively combined in order to achieve some reasonable trade-off. In particular, it is highlighted that a static choice of the corresponding weights can lead to not very effective handling of the effects given by the combination of the system conditions with the various exogenous’, while a dynamic choice may suit the purpose instead. Moreover, the simulations show that the developed models and the set-up mathematical program can be fruitfully leveraged for inferring indications on the devices’ sizing.publishedVersio

Incidence of smoking in respiratory measurements in the prehabilitation stage of cardiac surgery

El tabaco es la auténtica epidemia de nuestros días. La OMS considera que el tabaquismo es el principal problema de salud en los países desarrollados y es la primera causa de mortalidad prevenible y evitable en estos países. En cirugía cardíaca el deterioro de la función pulmonar que se observa en el periodo posoperatorio es debido a la técnica quirúrgica, la anestesia, el uso de ventilación mecánica y la necesidad de utilizar circulación extracorpórea (CEC). Es sabido que el deterioro de la función pulmonar en el período posquirúrgico desciende un 60% aproximadamente por lo tanto es necesario entrenar la capacidad pulmonar desde la etapa pre quirúrgica. Las complicaciones respiratorias son importantes y frecuentes en el posoperatorio de la cirugía torácica y abdominal. En este estudio las mediciones respiratorias que se registraron fueron: Presión Inspiratoria Máxima, Pico Flujo Máximo y Pico Flujo Tosido (PiMáx, PFM y PFT respectivamente), en el día de ingreso del paciente al hospital, el día previo a la cirugía y el día posterior a la cirugía ya sin soporte ventilatorio

Incidencia del tabaquismo en mediciones respiratorias en la etapa de prehabilitación de cirugía cardíaca

El presente análisis tiene como objetivo demostrar el grado de influencia del tabaquismo en las mediciones respiratorias de pacientes que están próximos a ser sometidos a una cirugía cardíaca. La metodología que se utilizó para obtener los datos del análisis, consiste en el método de investigación de campo que es por contacto directo con pacientes, tanto para la evaluación como para el tratamiento correspondiente durante su estadía hospitalaria. Se realizó una evaluación prequirúrgica al momento del ingreso del paciente al hospital, que consistió en recolectar datos personales, factores de riesgo, diagnóstico, mediciones respiratorias (PiMáx, FEM y PFT) y exámenes complementarios. Posteriormente la etapa prequirúrgica consistió enbrindar al paciente ejercicios respiratorios como espirometría de incentivo y burbujeos espiratorios, y una charla prequirúrgicaeducando al paciente y a su familia sobre la patología sufrida y los métodos que se emplearan para su tratamiento. 24hs previas a la operación, las mediciones respiratorias volvieron a ser registradas para evidenciar cambios propios del tratamiento. En la etapa posquirúrgica, una vez que el paciente se encontró sin soporte ventilatorio, las mediciones respiratorias se registraban nuevamente, con el paciente sentado al borde de la cama. En los días posteriores, hasta el alta del paciente, el tratamiento kinésico se basó en los objetivos de la etapa posquirúrgica propuestos por la Publicación del Consejo Nacional de Residentes de Cardiología en su libro Recuperación Cardiovascular. Finalmente se concluye que, si bien al comparar mediciones entre ambos grupos ninguno presentó mediciones notablemente superiores respecto a otro, queda bien en claro que el tratamiento kinésico otorgado en este estudio dió mayores y mejores resultados en el grupo no fumador. Por lo tanto, es válido afirmar que el tabaquismo sí influye negativamente en las mediciones respiratorias de pacientes que serán sometidos a una cirugía cardíaca, y que el aparato respiratorio de los pacientes no fumadores presenta mayor versatilidad a la hora de ser sometido a un tratamiento kinésico de prehabilitación cardíaca para la cirugía

Diagnosis of primary headache in children younger than 6 years: A clinical challenge

Background: Criteria defined by the International headache Society are commonly used for the diagnosis of the different headache types in both adults and children. However, some authors have stressed some limits of these criteria when applied to preschool age. Objective: Our study aimed to describe the characteristics of primary headaches in children younger than 6 years and investigate how often the International Classification of Headache Disorders (ICHD) criteria allow a definitive diagnosis. Methods: This retrospective study analysed the clinical feature of 368 children younger than 6 years with primary headache. Results: We found that in our patients the percentage of undefined diagnosis was high when either the ICHD-II or the ICHD-III criteria were used. More than 70% of our children showed a duration of their attacks shorter than 1 hour. The absence of photophobia/phonophobia and nausea/vomiting significantly correlate with tension-type headache (TTH) and probable TTH. The number of first-degree relatives with migraine was positively correlated to the diagnosis of migraine in the patients (p<0.001). Conclusions: Our study showed that the ICHD-III criteria are difficult to use in children younger than 6 years. The problem is not solved by the reduction of the lowest duration limit for the diagnosis of migraine to 1 hour, as was done in the ICHD-II

Parametric and nonparametric two-sample tests for feature screening in class comparison: a simulation study

Background. The identification of a location-, scale- and shape-sensitive test to detect differentially expressed features between two comparison groups represents a key point in high dimensional studies. The most commonly used tests refer to differences in location, but general distributional discrepancies might be important to reveal differential biological processes.                                                         Methods. A simulation study was conducted to compare the performance of a set of two-sample tests, i.e. Student's t, Welch's t, Wilcoxon-Mann-Whitney, Podgor-Gastwirth PG2, Cucconi, Kolmogorov-Smirnov (KS), Cramer-von Mises (CvM), Anderson-Darling (AD) and Zhang tests (ZK, ZC and ZA) which were investigated under different distributional patterns. We applied the same tests to a real data example.                   Results. AD, CvM, ZA and ZC tests proved to be the most sensitive tests in mixture distribution patterns, while still maintaining a high power in normal distribution patterns. At best, the AD test showed a loss in power of ~ 2% in the comparison of two normal distributions, but a gain of ~ 32% with mixture distributions respect to the parametric tests. Accordingly, the AD test detected the greatest number of differentially expressed features in the real data application.   Conclusion. The tests for the general two-sample problem introduce a more general concept of 'differential expression', thus overcoming the limitations of the other tests restricted to specific moments of the feature distributions. In particular, the AD test should be considered as a powerful alternative to the parametric tests for feature screening in order to keep as many discriminative features as possible for the class prediction analysis

A Development of a New Image Analysis Technique for Detecting the Flame Front Evolution in Spark Ignition Engine under Lean Condition

The aim of herein work is to develop an automatized algorithm for detecting, as objectively as possible, the flame front evolution of lean/ultra-lean mixtures ignited by low temperature plasma-based ignition systems. The low luminosity characterizing the latter conditions makes both kernel formation and combustion development difficult to detect accurately. Therefore, to estimate the igniter capability to efficiently ignite the mixture, ever more performing tools are required. The present work proposes a new image analysis technique, based on a dual-exposure fusion algorithm and on Convolutional Neural Networks (CNNs), to process low brightness images captured via high-speed camera on an optical engine. The performance of the proposed algorithm (PA) is compared to the one of a base reference (BR) algorithm used by the same research group for the imaging analysis. The comparison shows the capability of PA to quantify the flame radius of consecutive combustion cycles with lower dispersion if compared to BR and to correctly detect some events considered as misfires or anomalies by BR. Moreover, the proposed method shows greater capability to detect, in advance, the kernel formation with respect to BR, thus allowing a more detailed analysis of the performance of the igniters. A metric quantitative analysis is carried out, as well, to confirm the above-mentioned results. Therefore, PA results to be more suitable for analyzing ultra-lean combustions, heavily investigated to meet the increasingly stringent legislation on the internal combustion engines. Finally, the proposed algorithm allows us to automatically estimate the flame front evolution, regardless of the user’s interpretation of the phenomenon

Migration and Trade during the Belle Époque in Argentina (1870-1913)

Between 1870 to 1914 the Argentine economy performed spectacularly with a yearly average real growth rate of 5.94 per cent. Increased resource endowment in both land and labor, via migration, and openness to trade have been considered the two main drivers of this success. In this paper we underline the central role of Argentine immigration in contributing not only to increase resource endowments, but also to lower trade costs boosting exports and imports. By considering Argentine bilateral trade and migration from eight European countries (Austro-Hungarian Empire, Belgium, France, Germany, Italy, Spain, Switzerland and United Kingdom) we use a migration-augmented gravity model to estimate the contribution of the massive in ows of Europeans. In particular, we nd that the main pro-trade e ect was on imports: an increase of 10 per cent of migrants from one country could increase imports up to 8 per cent from the same trade partner. To overcome the typical endogeneity problem our study proposes migration to the US from the same countries as a instruments that could capture the same push (but not Argentine pull) factors triggering European out-migration

Designing Robust API Monitoring Solutions

racing the sequence of library calls and system calls that a program makes is very helpful to characterize its interactions with the surrounding environment and, ultimately, its semantics. However, due to the entanglements of real-world software stacks, accomplishing this task can be surprisingly challenging as we take accuracy, reliability, and transparency into the equation. In this article, we identify six challenges that API monitoring solutions should overcome in order to manage these dimensions effectively and outline actionable design points for building robust API tracers that can be used even for security research. We then detail and evaluate SNIPER, an open-source API tracing system available in two variants based on dynamic binary instrumentation (for simplified in-guest deployment) and hardware-assisted virtualization (realizing the first general user-space tracer of this kind), respectively

Value of green hydrogen when curtailed to provide grid balancing services

This paper evaluates the potential of grid services in France, Italy, Norway and Spain to provide an alternative income for electrolysers producing hydrogen from wind power. Grid services are simulated with each country's data for 2017 for energy prices, grid services and wind power profiles from relevant wind parks. A novel metric is presented, the value of curtailed hydrogen, which is independent from several highly uncertain parameters such as electrolyser cost or hydrogen market price. Results indicate that grid services can monetise the unused spare capacity of electrolyser plants, improving their economy in the critical deployment phase. For most countries, up-regulation yields a value of curtailed hydrogen above 6 €/kg, over 3 times higher than the EU's 2030 price target (without incentives). However, countries with large hydro power resources such as Norway yield far lower results, below 2 €/kg. The value of curtailed hydrogen also decreases with hydrogen production, corresponding to the cases of symmetric and down-regulation.This publication has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under the European Union's Horizon 2020 research and innovation programme under grant agreement No. 779469. Any contents herein reflect solely the authors' view. The FCH 2JU and the European Commission are not responsible for any use that may be made of the information herein contained. TECNALIA is a “CERVERA Technology Centre of Excellence” recognised by the Spanish Ministry of Science and Innovation. The authors wish to thanks Stefano Rossi of ARERA for his advices on the Italian energy market and regulation aspects