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A New Fault Tolerant Control Method for a Three Phase Modular Multilevel Converter Under an Arm Failure
No full textInternational audienceModular multilevel converter (MMC) is widely used in medium to high power applications. One of the significant features that an MMC can provide is the fault tolerant operation, which improves the reliability of the converter. Although there are extensive efforts towards addressing the fault tolerant operation of a modular multilevel converter, the control of a three phase MMC when one of its arms is out of service, therefore, must be bypassed, is not yet discussed. The objective of the paper is to overcome this problem, by proposing a control method, which allows to control separately, the voltages of the capacitors in the upper and lower arms, except for the voltages of the capacitors belonging to the bypassed arm. In order to meet these requirements, the injected circulating current in each phase must contain a DC component, but also an AC component, oscillating at the fundamental frequency. The feasibility of the proposed fault tolerant method has been confirmed by simulations conducted on a three phase MMC connected to a low voltage grid using MATLAB/SIMULINK
Alterations of gait kinematics depend on the deformity type in the setting of adult spinal deformity
No full textInternational audiencePurpose :To evaluate 3D kinematic alterations during gait in Adult Spinal Deformity (ASD) subjects with different deformity presentations.Methods :One hundred nineteen primary ASD (51 ± 19y, 90F), age and sex-matched to 60 controls, underwent 3D gait analysis with subsequent calculation of 3D lower limb, trunk and segmental spine kinematics as well as the gait deviation index (GDI). ASD were classified into three groups: 51 with sagittal malalignment (ASD-Sag: SVA > 50 mm, PT > 25°, and/or PI-LL > 10°), 28 with only frontal deformity (ASD-Front: Cobb > 20°) and 40 with only hyperkyphosis (ASD-HyperTK: TK > 60°). Kinematics were compared between groups.ResultsASD-Sag had a decreased pelvic mobility compared to controls with a decreased ROM of hips (38 vs. 45°) and knees (51 vs. 61°). Furthermore, ASD-Sag exhibited a decreased walking speed (0.8 vs. 1.2 m/s) and GDI (80 vs. 95, all p < 0.05) making them more prone to falls. ASD-HyperTK showed similar patterns but in a less pronounced way. ASD-Front had normal walking patterns. GDI, knee flex/extension and walking speed were significantly associated with SVA and PT (r = 0.30–0.65).ConclusionSagittal spinal malalignment seems to be the driver of gait alterations in ASD. Patients with higher GT, SVA, PT or PI-LL tended to walk slower, with shorter steps in order to maintain stability with a limited flexibility in the pelvis, hips and knees. These changes were found to a lesser extent in ASD with only hyperkyphosis but not in those with only frontal deformity. 3D gait analysis is an objective tool to evaluate functionality in ASD patients depending on their type of spinal deformity
Atmospheric dispersion modelling of gaseous emissions from Beirutinternational airport activities
No full textInternational audienceThe projected increase of civil aviation activity, the degradation of air quality and the location of Beirut Airport embedded in a very urbanized area, in addition to the special geography and topography surrounding the airport which plays a significant role in drawing emissions to larger distances, demanded anassessment of the spatial impact of the airport activities on the air quality of Beirut and its suburbs. This is the first study in the Middle East region that model pollutant concentrations resulting from an international airport's activities using an advanced atmospheric dispersion modelling system in a country with no data. This followed validation campaigns showing very strong correlations (r = 0.85) at validation sites as close as possible to emission sources. The modelling results showed extremely high NO2 concentrations within the airport vicinity, i.e., up to 110 µg•m-3 (which is greater than the World Health Organization annual guidelines) posing a health hazard to the workers in the ramp. The major contribution of Beirut-Rafic Hariri International Airport to the degradation of air quality was in the airport vicinity; however, it extended to Beirut and its suburbs in addition to affecting the seashore area due to emissions along the aircraft trajectory; this isan aspect rarely considered in previous studies. On the other hand, elevated volatile organic compound levels were observed near the fuel tanks and at the aerodrome center. This study provides (i) a methodology to assess pollutant concentrations resulting from airport emissions through the use 554 of an advanced dispersion model in a country with no data; and (ii) a tool for policy makers to better understand the contribution of the airport's operations to national pollutant emissions, which is vital for mitigation strategies and health impact assessments
Sprouts Use as Functional Foods. Optimization of Germination of Wheat (Triticum aestivum L.), Alfalfa (Medicago sativa L.), and Radish (Raphanus sativus L.) Seeds Based on Their Nutritional Content Evolution
No full textInternational audienceWheat, alfalfa, and radish sprouts are well-renowned for their high nutritional content. However, their optimal imbibition and germination durations are rarely considered in the literature. In this study, reduced imbibition times of 3 h, 10 h, and 4 h were demonstrated for the wheat, alfalfa, and radish seeds, respectively. The evolution of their crude fat, proteins, polyphenols, antioxidant activity, and vitamins were investigated over 7 days of germination. The crude fat and protein loads of these sprouts slightly varied during germination, whereas the phenolic compounds and antioxidant activity maxed out at day 7, 5, and 6 for the wheat, alfalfa, and radish sprouts, respectively, with significant levels of catechin. The vitamins highly increased, showing noteworthy yet different peaks of growth depending on the seed and the vitamin analyzed. Interestingly, alfalfa and radish sprouts, taken at their optimal germination day, would decidedly contribute to meet our Recommended Daily Allowances (RDAs) of vitamins E, A, and B6. Overall, for a greater nutritional content and a potential use of these sprouts as nutraceutical ingredients, our results suggested to leave the wheat, alfalfa, and radish seeds to germinate only over 7, 4, and 6 days, respectively, after which their nutritional quality tended to decrease
Clinical Correlates of Measured and Predicted Resting Energy Expenditure in Patients with Anorexia Nervosa: A Retrospective Cohort Study
No full textInternational audienceResting energy expenditure (REE; i.e., the calorie amount required for 24 h during a non-active period) is an important parameter in nutritional rehabilitation of patients with anorexia nervosa (AN). This study determined whether age, body mass index, AN duration/subtype/specific symptoms/clinical severity, cognitive function alterations, and psychiatric comorbidities influenced REE or the difference between the calculated and estimated REE. Patients with AN who were followed at a daycare treatment facility between May 2017 and January 2020 (n = 138) underwent a complete assessment that included the MINI, Eating Disorder Examination Questionnaire, d2 test of attention, body fat composition by bioelectrical impedance analysis (BIA) and REE measurement by indirect calorimetry (REEIC). AN subtype (N = 66 for restrictive subtype and N = 69 for non-restrictive subtype; p = 0.005), free-fat mass (3 years). Overall, REE was higher in patients with restrictive than non-restrictive AN. In the absence of BIA measures, REE-estimating equations should take into account AN duration
Relationship between chemical composition, source apportionment and oxidative potential of PM2.5 in an East-Mediterranean site
No full textInternational audienceAmong the different air pollutants, PM2.5 can be easily inhaled into the lungs and might cause diverse health effects especially cardiovascular and respiratory diseases (Anderson et al. 2012). That is why it is important to understand which species contribute the most to the toxicity of these particles. One of the practical indicators recently used for the evaluation of the oxidative capacity of PM as whole is the oxidative potential (OP) (Crobeddu et al. 2017). In this study, the oxidative potential of PM2.5 was evaluated using dithiothreitol (DTT) and ascorbic acid (AA) assays on samples collected in an urban site under industrial influence in the East Mediterranean: Zouk Mikael region (ZK) in Lebanon. ZK is characterized by the biggest power plant in the country which runs on heavy fuel oil, a high density of population (4,200 inhabitants/km2) along with high road traffic and the use of diesel generators for electricity generation.The mean volume normalized OP-AA value was 0.67 ± 0.29 nmol.min¬-1.m-3. On the other hand, the mean OP-DTTv was 0.52 ± 0.32 nmol.min-1.m-3. Different approaches were used to study the relationship between the characterized species (carbonaceous matter, ions, major and trace elements, and organic compounds) or the sources contribution and OP values. Spearman correlations and hierarchical classification after principal components analysis showed that both OP-DTTv and OP-AAv at ZK were correlated with HFO combustion, diesel generators, crustal dust, road dust and vehicular emissions sources.A multiple linear regression approach was applied to the contribution of the sources obtained by PMF and the OP values at ZK site in order to estimate the contributions of PM sources to OP values. The results showed that the sources that largely contribute to the PM2.5 mass (crustal dust and ammonium sulfate sources) were not the major sources contributing to the values of OP. However, local anthropogenic sources such as biomass burning (33% of OP-AAv and 9% of OP-DTTv), vehicular emissions (20% and 23%), and heavy fuel oil combustion (31% and 46%) contribute the most to the OP-AAv and OP-DTTv, respectively. This study is a first in Lebanon and in the East Mediterranean and the Middle Eastern region presenting results of oxidative potential (OP-AA and OP-DTT), studying the correlation between the OP values and different classes of compounds (carbonaceous, ionic, elemental, and organic) and attributing OP values to the PM2.5 identified sources at the sites. The findings of this study will be of utmost importance to policymakers in order to implement policies to protect health and improve the air quality in the region
Are Consumers Aware of Sustainability Aspects Related to Edible Insects? Results from a Study Involving 14 Countries
No full textInternational audienceIn recent years, edible insects have been suggested as an alternative food that is more sustainable compared with other sources of animal protein. However, knowledge about the sustainability aspects associated with this source of food may play a role in convincing consumers to adopt insects as part of their diet. In this context, the present study investigated the level of knowledge about the sustainability of edible insects in a group of people originating from 14 countries, with some naturally entomophagous and others not. To measure the knowledge, 11 items were selected and the scores obtained were tested with statistical tools (t-test for independent samples, analysis of variance—ANOVA) to search for differences according to sociodemographic and socioeconomic characteristics, geographical origin, and consumption habits of edible insects. The obtained results showed that, in general, knowledge is moderate, with the values of the average scores for the 11 items investigated ranging from 0.23 ± 0.99 to 0.66 ± 1.02, on a scale ranging from −2 (=very low knowledge) to 2 (=very high knowledge). The highest scores were found for items relating to the lower use of animal feed and lower emission of greenhouse gases required for the production of insects compared with beef. When investigating the differences between groups of participants, significant differences were generally found, revealing a trend for higher knowledge among males and young adults, for participants residing in urban areas and in countries such as Spain, Mexico, and Poland, and for participants with higher education levels and higher incomes. When testing the influence of consumption variables on the level of knowledge, the results showed a higher knowledge for participants who had already consumed insects or are willing to consume them. Finally, it was observed that higher knowledge was found for participants whose motivation to consume insects related to curiosity, a wish to preserve the planet, the gastronomic characteristics of insects, and their nutritional value. In conclusion, these results clearly indicate a very marked influence of a number of variables on the knowledge about the sustainability of edible insects, and this may be helpful to delineate strategies to effectively raise knowledge and eventually increase the willingness to consider insects as a more sustainable alternative to partially replace other protein foods, even in countries where this is a not a traditional practice
Intracellular reactive oxygen species trafficking participates in seed dormancy alleviation in Arabidopsis seeds
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A channel selection game for multi-operator LoRaWAN deployments
No full textInternational audienceWith over 75 billion Internet of Things (IoT) devices expected worldwide by the year 2025, inaugural MAC layer solutions for long-range IoT deployments no longer suffice. LoRaWAN, the principal technology for comprehensive IoT deployments, enables low power and long range communications. However, synchronous transmissions on the same spreading factors and within the same frequency channel, augmented by the necessary clustering of IoT devices, will cause collisions and drops in efficiency. The performance is further impacted by the shortage of radio resources and by multiple operators utilizing the same unlicensed frequency bands. In this paper, we propose a game theoretic based channel selection algorithm for LoRaWAN in a multi-operator deployment scenario. We begin by proposing an optimal formulation for the selection process with the objective of maximizing the total normalized throughput per spreading factor, per channel. Then, we propose centralized optimal approaches, as well as distributed algorithms, based on reinforcement learning and regret matching dynamics, to finding both the Nash and Correlated equilibria of the proposed game. We simulate our proposals and compare them to the legacy approach of randomized channel access, stressing their efficiency in improving the total normalized throughput as well as the packet delivery ratios
