Predictive Control of Variable Speed Wind Energy Conversion System with Multi Objective Criterions

The paper presents an improved predictive direct rotor current control of a variable speed wind energy conversion system. The conversion chain uses a Doubly Fed Induction Generator DFIG whereas the control method is based on Finite States Space Model Predictive Control FS-MPC of the converter. The proposed control method selects the optimal switching state of the inverter that minimizes the error between orthogonal rotor current components predictions to their computed values. The optimal voltage vector that minimizes a cost function is then applied to the output of the power converter. Once the proposed predictive strategy is validated, multi-level converters well suited for high power application are then used to improve and highlight the obtained results. The proposed predictive control strategy uses only one sample time prediction and it is intuitive since it is very simple for implementation, avoids the cascade structure of several linear controllers and provides best performance

THE RELATIONSHIP BETWEEN VALUE CONFLICT AND ACADEMIC ADJUSTMENT AMONG STUDENTS AT THE HIGHER INSTITUTE OF SPORT AND PHYSICAL EDUCATION (KSAR SAÏD) UNIVERSITY OF MANOUBA, TUNISIA

This study aimed to identify the impact of value conflict a negative social process that involves exposure to two opposing, contradictory concepts and requires violation of at least one of the values on the academic adjustment of students at the “Higher Institute of Sport and Physical Education (Ksar saïd)” of “University of Manouba”. Two questionnaires were designed to measure: 1) the extent to which students experience value conflict and 2) students’ levels of academic adjustment in terms of curriculum, goals, time management and personal relationships. The questionnaire was administered to a random sample of 739 students. Participant responses to these questionnaires indicate average levels of value conflict and academic adjustment. Results reveal a moderate level of value conflict among the “Higher Institute of Sport and Physical Education (Ksar saïd)” students with the highest level found in the economic domain, followed by the social domain and cultural domain in third among. In terms of academic adjustment, students reported a moderate level, indicating some difficulties in adjusting to the “Higher Institute of Sport and Physical Education (Ksar saïd)” life. Academic adjustment levels were highest in relation to students’ goals, followed by personal relationships, which are closely related areas. Article visualizations

Experimental Validation of Direct Predictive Control of Variable Speed Wind Energy Conversion System Based on DFIG

The paper presents the design and the implementation of a direct predictive control of a variable speed wind energy conversion system. The conversion chain uses a Doubly Fed Induction Generator DFIG whereas the control method is based on a Finite States Model Predictive Control FS-MPC. The proposed control method selects the optimal switching state of the two levels back to back power converter that minimizes the cost function, where this optimal voltage vector is applied on the output of the power converter in next sampling time. The proposed predictive control strategy uses only one sample time prediction and it is intuitive since it is very simple for implementation. In order to adjust the measured rotor currents to track their references, the error between orthogonal rotor current components predictions to their computed values used to select the optimal vector and applied on the power converter in rotor side CSR in next sampling time. On other side, based on the error between the active and reactive power prediction and their references of the electrical grid, the predictive algorithm control of the gird side converter CSG kept the Dc-link voltage constant and guarantee that the whole system functioning with unity power factor. The experimental results confirm the advantages of using this structure for wind energy conversion system and the effectiveness of the proposed control strategy

Working Memory in Overweight Boys during Physical Education Classes

This study examined the effect of small-sided football games (SSFG) and small-sided Ultimate Frisbee games (SSUFG) on working memory, response times, and feeling mood of boys with overweight. Twenty-eight boys (age 12.23 ± 1.58 years) participated in two trials during physical education lessons (20-min SSFG and 20-min SSUFG) in a counterbalanced, randomized crossover design. The response times and feeling mood were measured for all participants post-exercise through the Sternberg paradigm and feeling scale. For the response times, the paired samples t-test revealed a significantly better reaction time after SSUFG at the “One item level” of the Sternberg paradigm (p = 0.014, Hedges’ g = 0.27, small effect) and (p = 0.010, Hedges’ g = 0.74, medium effect), at “Three item level” (p = 0.000106, Hedges’ g = 1.88, very large effect). The SSFG also showed vigor at the “Five item level” (p = 0.047, Hedges’ g = 0.61, medium effect). For the feeling mood, the feeling score was significantly higher after the SSUFG session than the SSFG session and the increase in feeling scores observed after switching from SSFG to SSUFG was significantly different (p < 0.001) from the decrease observed in feeling scores after switching from SSUFG to SSFG. Therefore, the results of the study allow the teacher to introduce new sports and reflect on the motor tasks he or she proposes for boys with overweight during physical education classes

Composition and Anticoagulant Potential of Chondroitin Sulfate and Dermatan Sulfate from Inedible Parts of Garfish (Belone belone)

Glycosaminoglycans (GAGs) play a crucial role due to their significant biomedical functions. Chondroitin sulfate (CS) and dermatan sulfate (DS), the main representative family of GAGs, were extracted and purified from garfish (Belone belone) by-products, i.e., skin (GSB), bones (GCB), and heads (GHB), and their composition and anticoagulant activity were investigated. CS/DS were purified by ion-exchange chromatography with yields of 8.1% for heads, 3.7% for skin, and 1.4% for bones. Cellulose acetate electrophoresis was also explored for analyzing the extracted CS/DS. Interestingly, GHB, GSB, and GCB possessed sulfate contents of 21 ± 2%, 20 ± 1%, and 20 ± 1.5%, respectively. Physico-chemical analysis showed that there were no significant differences (p &gt; 0.05) between the variances for sulfate, uronic acid, and total sugars in the GAGs extracted from the different parts of fish. Disaccharide analysis by SAX-HPLC showed that the GSB and GCB were predominately composed of ΔDi-4S [ΔUA-GalNAc 6S] (74.78% and 69.22%, respectively) and ΔDi-2,4S [ΔUA2S-GalNAc 4S] (10.92% and 6.55%, respectively). However, the GHB consisted of 25.55% ΔDi-6S [ΔUA-GalNAc 6S] and 6.28% ΔDi-2,6S [ΔUA2S-GalNAc 4S]. Moreover, classical anticoagulation tests were also used to measure their anticoagulant properties in vitro, which included the activated partial thromboplastin time, prothrombin time, and thrombin time. The CS/DS isolated from garfish by-products exhibited potent anticoagulant effects. The purified CS/DS showed exceptional anticoagulant properties according to this research and can be considered as a new agent with anticoagulant properties

The Effect of Spatial Ability in Learning From Static and Dynamic Visualizations: A Moderation Analysis in 6-Year-Old Children

Previous studies with adult human participants revealed mixed effects regarding the relation between spatial ability and visual instructions. In this study, we investigated this question in primary young children, and particularly we explored how young children with varying levels of spatial abilities integrate information from both static and dynamic visualizations. Children (M = 6.5 years) were instructed to rate their invested mental effort and reproduce the motor actions presented from static and dynamic 3D visualizations. The results indicated an interaction of spatial ability and type of visualization: high spatial ability children benefited particularly from the animation, while low spatial ability learners did not, confirming therefore the ability-as-enhancer hypothesis. The study suggests that an understanding of children spatial ability is essential to enhance learning from external visualizations

Assessment of Radio Frequency Electromagnetic Field Exposure Induced by Base Stations in Several Micro-Environments in France

Recently, the monitoring of the radiofrequency electromagnetic field (RF-EMF) exposure induced by cellular networks has received a great deal of attention. In this work, a set of 70 microenvironments (MEs) located in urban and rural areas are selected in France under, on the one hand, the French Beyond5G project, and on the other hand, the 5G expOsure, causaL effects and rIsk perception through citizen engagement (GOLIAT) EU project. The purpose of this study is to assess the RF-EMF DL exposure in residential areas, downtowns, business areas, train stations, and public transport rides. For that, we employ the personal ExpoM-RF4 dosimeter placed inside a backpack to perform the measurements in different MEs. To take into consideration the effect of the presence of the human body near the dosimeter, we propose a correction approach that is mainly based on comparing the measurements given by ExpoM-RF4 to the ones provided by a reference system using the Tektronix real-time spectrum analyzer (RTSA) far from the body. Then, we use metrics, such as the quadratic mean, standard deviation, and median of the electric (E) field to carry out a comparative study between different MEs with different RF bands. It was found that the RF-EMF exposure levels for all MEs are well below the maximum allowable exposure limit prescribed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). In addition, we perform clustering analyses using the K-Means technique to group the MEs with comparable exposure levels. The results show that the exposure level is low, but generally higher in MEs located in Paris than in the other considered areas (i.e., Massy and three villages, namely Igny, Bures-sur-Yvette and Gif-Sur-Yvette). For example, we observe that outdoor MEs can be grouped into three clusters, where the average total E fields (ATEFs) are 0.77 V/m, 0.35 V/m, and 0.08 V/m for the MEs belonging to the first, second and third clusters, respectively. Note that the first cluster here mainly contains the MEs located in Paris. This can be explained by the important number of antennas deployed in that area to serve the huge amount of users. We also observe few locations with exceptions confirming the presence of heterogeneous environments in the vicinity of some areas.</p

Laparoscopic Extirpation of Adrenal Gland Ganglioneuroma Incidentally Diagnosed During Evaluation for Patchy Alopecia Areata in an Adolescent Boy

We present a 17-year-old boy with an incidentally diagnosed left adrenal ganglioneuroma (GN) during the diagnostic work up of alopecia areata (AA). Clinical Presentation and Intervention Laboratory investigations revealed only vitamin D deficiency. Laparoscopic adrenalectomy was performed and GN was confirmed histologically. At follow-up, the vitamin D supplements improved the vitamin D levels followed by the gradual regression of AA. However, AA recurred 18 months later despite the normal serum vitamin D levels and no tumor recurrence. Conclusion. Further studies should reveal the relationship between AA and GN as well as the role of vitamin D in AA

Encysted hydrocele of the canal of Nuck in an 11-month-old child with a past history of duodenal atresia and Arnold-Chiari malformation: A case report.

Hydrocele of the canal of Nuck is a rare developmental disorder and represents of a homolog of hydrocele of spermatic cord in males. Hydrocele of the canal of Nuck is a very rare cause of inguinal swelling in female infants and children. It results from the failure of obliteration of the distal portion of evaginated parietal peritoneum within the inguinal canal, which forms a sac containing fluid. We describe a case of hydrocele of the canal of Nuck in an 11-month-old girl with a past medical history of duodenal atresia and Arnold-Chiari malformation. Physical examination and ultrasound revealed a soft, cystic, noncompressible, and non-fluctuant labial mass measuring approximately 5 cm. The patient underwent surgical exploration through a right skin crease incision. The cystic lesion was histologically confirmed to be a non-communicated hydrocele of canal of Nuck. The child is doing well at 1-year follow-up with no swelling or recurrence on the operated side. Hydrocele of the canal of Nuck is a rare developmental disorder but should be considered in a differential diagnosis in young girls with an inguino-labial swelling.The publication of this article was funded by the Qatar National Librar

L'Islam. Morale et politique, 1986

Chikha Elisabeth. L'Islam. Morale et politique, 1986. In: Hommes et Migrations, n°1102, avril 1987. Islam de France et de Belgique. pp. 11-12