Optimal frequency control in microgrid system using fractional order PID controller using Krill Herd algorithm

This paper investigates the use of fractional order Proportional, Integral and Derivative (FOPID) controllers for the frequency and power regulation in a microgrid power system. The proposed microgrid system composes of renewable energy resources such as solar and wind generators, diesel engine generators as a secondary source to support the principle generators, and along with different energy storage devices like fuel cell, battery and flywheel. Due to the intermittent nature of integrated renewable energy like wind turbine and photovoltaic generators, which depend on the weather conditions and climate change this affects the microgrid stability by considered fluctuation in frequency and power deviations which can be improved using the selected controller. The fractional-order controller has five parameters in comparison with the classical PID controller, and that makes it more flexible and robust against the microgrid perturbation. The Fractional Order PID controller parameters are optimized using a new optimization technique called Krill Herd which selected as a suitable optimization method in comparison with other techniques like Particle Swarm Optimization. The results show better performance of this system using the fractional order PID controller-based Krill Herd algorithm by eliminates the fluctuations in frequency and power deviation in comparison with the classical PID controller. The obtained results are compared with the fractional order PID controller optimized using Particle Swarm Optimization. The proposed system is simulated under nominal conditions and using the disconnecting of storage devices like battery and Flywheel system in order to test the robustness of the proposed methods and the obtained results are compared.У статті досліджено використання регуляторів пропорційного, інтегрального та похідного дробового порядку (FOPID) для регулювання частоти та потужності в електромережі. Запропонована мікромережева система складається з поновлюваних джерел енергії, таких як сонячні та вітрогенератори, дизельних генераторів як вторинного джерела для підтримки основних генераторів, а також з різних пристроїв для накопичування енергії, таких як паливна батарея, акумулятор і маховик. Через переривчасту природу інтегрованої відновлювальної енергії, наприклад, вітрогенераторів та фотоелектричних генераторів, які залежать від погодних умов та зміни клімату, це впливає на стабільність мікромережі, враховуючи коливання частоти та відхилення потужності, які можна поліпшити за допомогою вибраного контролера. Контролер дробового порядку має п’ять параметрів порівняно з класичним PID-контролером, що робить його більш гнучким та надійним щодо збурень мікромережі. Параметри PID-контролера дробового порядку оптимізовані за допомогою нової методики оптимізації під назвою «зграя криля», яка обрана як підходящий метод оптимізації порівняно з іншими методами, такими як оптимізація методом рою частинок. Результати показують кращі показники роботи цієї системи за допомогою алгоритму «зграя криля», заснованого на PID-контролері дробового порядку, виключаючи коливання частоти та відхилення потужності порівняно з класичним PID-контролером. Отримані результати порівнюються з PID-контролером дробового порядку, оптимізованим за допомогою оптимізації методом рою частинок. Запропонована система моделюється в номінальному режимі роботи та використовує відключення накопичувальних пристроїв, таких як акумулятор та маховик, щоб перевірити надійність запропонованих методів та порівняти отримані результати

Effect of iron and growth inhibitors on siderophores production by Pseudomonas fluorescens

The ability of Pseudomonas to grow and to produce siderophores is dependent on the iron content and the type of carbon sources in the medium. Under conditions of low-iron concentration the Pseudomonas isolates studied produced yellow-green fluorescent iron-binding peptide siderophores and the biosynthesis of this siderophores was affected by several different environmental parameters. Four basal media, supplemented with different concentration of iron, were employed to study the effect of iron and different organic carbon sources on siderophore production in Pseudomonas fluorescens. The highest siderophores concentration was obtained in succinate medium. Ferric iron increased the growth yield and completely repressed siderophores production above 200 μg/l, but had a positive effect below 160μg/l. Penicillin and lead elicited the production of siderophores in the presence of excess iron. Pre-treatment of the standard succinate medium with a,a-dipyridyl and 8-hydroxyquinoline to reduce the concentration of iron diminished both the growth yield and siderophore production, but a,a-dipyridyl increased significantly the amount of siderophores produced in the presence of 0.20 mg/l of the chelating ion.African Journal of Biotechnology Vol. 4 (7), pp. 697-702, 200

Health e-learning using virtual-reality technology in Algerian universities

Background: The virtual reality environments around the world are increasingly used in many areas, including education, where they offer new learning opportunities. This technology (virtual reality) is used as an information resource or as an educational tool where the student takes an active part in learning by interacting with the device. For the past ten years or so, virtual environments have been used in teaching, especially in history and science. Methods: Our work focuses on the educational potential offered by this technology at the Algerian University, and for this we have experimented virtual reality applications intended for the education of medicine using a virtual reality helmet “VR BOXâ€, which is a viewer hosting a smartphone. The students and teachers were looking through the VR BOX at a virtual human body and exploring the different body organs in 3D. Results: This simulation, not otherwise possible in class with the classical teaching tools, offered students and teachers the opportunity to immerse themselves in an extremely realistic environment and allowed them to have a fun, memorable and fascinating experience. According to them, the use of this technology could intervene, in addition to the course, to facilitate the understanding of concepts difficult to explain. One of the main advantages of using this technology, say some teachers, is above all the interest and the motivation it arouses among the students. Conclusion: The study presented in this article demonstrates the results of using virtual-reality environments for e-learning in the Algerian University in general, and for Health e-learning in particular. Furthermore, this experience and in view of the availability of virtual reality tools in Algeria at a very reasonable price, shows that virtual reality is very promising for the class of tomorrow and seems reinvigorating the teaching in Algeria as well as elsewhere

Immunotherapy for B-Cell Neoplasms using T Cells expressing Chimeric Antigen Receptors : From antigen choice to clinical implementation

Immunotherapy with T cells expressing chimeric antigen receptors (CAR) is being evaluated as a potential treatment for B-cell neoplasms. In recent clinical trials it has shown promising results. As the number of potential candidate antigens expands, the choice of suitable target antigens becomes more challenging to design studies and to assess optimal efficacy of CAR. Careful evaluation of candidate target antigens is required to ensure that T cells expressing CAR will preferentially kill malignant cells with a minimal toxicity against normal tissues. B cells express specific surface antigens that can theoretically act as targets for CAR design. Although many of these antigens can stimulate effective cellular immune responses in vivo, their implementation in clinical settings remains a challenge. Only targeted B-cell antigens CD19 and CD20 have been tested in clinical trials. This article reviews exploitable B cell surface antigens for CAR design and examines obstacles that could interfere with the identification of potentially useful cellular targets