Sliding Mode Control Based DTC of Sensorless Parallel-Connected Two Five-Phase PMSM Drive System

Tounsi Kamel,Djahbar Abdelkader,Barkat Said,M. Al-Hitmi,Atif Iqbal 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

Sequential model predictive control for five‑level MMC‑based multi‑terminal HVDC systems

Ali Bouzidi,Said Barkat,Ali Akka,Mohamed Lokmane Bendaas 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.10

In this paper, a Sequential Model Predictive Control (SMPC) is proposed for controlling a Modular Multilevel Converter (MMC)-based Multi-Terminal high Voltage Direct Current (MTDC) grid. Based on an adequate predictive model of the grid side of each MMC unit, cost functions are designed and optimized to generate the appropriate switching states of each MMC. In addition to its ability to guarantee accurate power-sharing between deferent controlled MMCs units, the conspicuousfeatures of the propose MPC strategy are the sub-module capacitor voltages balancing and MMC circulating currents minimization. To validate the performance and the effectiveness of the proposed control approach in terms of its ability to achieve the desired performance under various operational conditions, comprehensive simulation studies are conducted on a four-terminal MMC-MTDC system.

L-rhamnose induces browning in 3T3-L1 white adipocytes and activates HIB1B brown adipocytes : L-RHAMNOSE INDUCES BROWNING IN WHITE ADIPOCYTES

Choi, Minji,Mukherjee, Sulagna,Kang, Nam Hyeon,Barkat, Jameel Lone,Parray, Hilal Ahmad,Yun, Jong Won Wiley Blackwell (John WileySons) 2018 IUBMB life Vol.70 No.6

<P>Induction of the brown adipocyte-like phenotype in white adipocytes (browning) is considered as a novel strategy to fight obesity due to the ability of brown adipocytes to increase energy expenditure. Here, we report that L-rhamnose induced browning by elevating expression levels of beige-specific marker genes, including Cd137, Cited1, Tbx1, Prdm16, Tmem26, and Ucp1, in 3T3-L1 adipocytes. Moreover, L-rhamnose markedly elevated expression levels of proteins involved in thermogenesis both in 3T3-L1 white and HIB1B brown adipocytes. L-rhamnose treatment in 3T3-L1 adipocytes also significantly elevated protein levels of p-HSL, p-AMPK, ACOX, and CPT1 as well as reduced levels of ACC, FAS, C/EBP, and PPAR, suggesting its possible role in enhancement of lipolysis and lipid catabolism as well as reduced adipogenesis and lipogenesis, respectively. The quick technique of efficient molecular docking provided insight into the strong binding of L-rhamnose to the fat-digesting glycine residue of (3)-adrenergic receptor (AR), indicating strong involvement of L-rhamnose in fat metabolism. Further examination of the molecular mechanism of L-rhamnose revealed that it induced browning of 3T3-L1 adipocytes via coordination of multiple signaling pathways through (3)-AR, SIRT1, PKA, and p-38. To the best of our knowledge, this is the first study to demonstrate that L-rhamnose plays multiple modulatory roles in the induction of white fat browning, activation of brown adipocytes, as well as promotion of lipid metabolism, thereby demonstrating its therapeutic potential for treatment of obesity. (c) 2018 IUBMB Life, 70(6):563-573, 2018</P>

Assessment of nutritional status in HIV-positive population

El Alama Hakim,Fatihi Touria,Benmoussa Adnane,Barkat Amina 경희대학교 융합한의과학연구소 2021 Oriental Pharmacy and Experimental Medicine Vol.21 No.1

The objective of this work is to assess the nutritional status of HIV-positive patients and to correlate it to the response to treatment and to certain parameters such as age, gender, socio-economic level, etc. to validate the various tools for assessing the nutritional status of the HIV-positive population. This prospective observational study was extended over a 6-month period and included 220 HIV-positive patients. The nutritional status of each patient was evaluated according to the following tools: exploitation sheet, anthropometric analysis, food survey and calculation of dietary intake, nutritional risk index and nutritional risk stratification. The sex ratio was 52.78, where 144 (65.46%) were women, the average age was 41.60 ± 11.05 years. The evaluation of energy intake showed that 82% of patients had a deficiency in intake relative to nutritional needs. The study population presented vitamin, mineral and micronutrient deficiencies. According to the nutritional risk stratification table we designed, 53% of patients were in grade 7 and 2% were in grade 12. Undernutrition among HIV-positive people was prevalent in the study population, which had a negative impact on the health status and well-being of patients. Correcting undernutrition states would correct anthropometric parameters and biological markers, thus reducing and/or stabilizing viral load and improving CD-ratio.

Sliding Mode Control Based DTC of Sensorless Parallel-Connected Two Five-Phase PMSM Drive System

Kamel, Tounsi,Abdelkader, Djahbar,Said, Barkat,Al-Hitmi, M.,Iqbal, Atif The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

Herbivore and phytohormone induced defensive response in kale against cabbage butterfly, Pieris brassicae Linn

Shahida Ibrahim,G.M. Mir,Abdul Rouf,Abdul Rasheed War,Barkat Hussain 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

The constitutive and induced resistance were studied in two varieties (Khanyari and Kawdari) of kale, Brassicaoleracea var. acephala in response to cabbage butterfly, Pieris brassicae infestation and exogenous application ofjasmonic acid (JA) and salicylic acid (SA). Phenols, condensed tannins, flavonoids and proteins were measuredat six days after JA (1 mM) and SA (1 mM) application and/or insect infestation. Plant damage and larvalweights were also recorded. Khanyari variety showed highest amounts of phenols (208.23 μg/g FW), condensedtannin (347.76 μg/g FW), flavonoids (175.61 μg/g FW) and proteins (0.71 mg/g FW) in plants pre-treated withJA and infested with insects. The PAL activity was high in response to JA application followed by insect infestation. Insects reared on Khanyari and Kawdari plants pre-treated with JA prior showed significantly reducedlarval weights (97.88 and 102.46 mg, respectively). Damage was low in plants pre-treated with JA in Khanyari at3, 6 and 9 days after treatment (10.52%, 8.52%, and 5.30%, respectively). Thus, JA can play an important role inplant defense in kale against P. brassicae.

THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW

Partnership, ALMA,Fomalont, E. B.,Vlahakis, C.,Corder, S.,Remijan, A.,Barkats, D.,Lucas, R.,Hunter, T. R.,Brogan, C. L.,Asaki, Y.,Matsushita, S.,Dent, W. R. F.,Hills, R. E.,Phillips, N.,Richards, A. M IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.808 No.1

Effect of wing form on the hydrodynamic characteristics and dynamic stability of an underwater glider

Muhammad Yasar Javaid,Mark Ovinis,Fakhruldin B.M. Hashim,Adi Maimun,Yasser M. Ahmed,Barkat Ullah 대한조선학회 2017 International Journal of Naval Architecture and Oc Vol.9 No.4

We are developing a prototype underwater glider for subsea payload delivery. The idea is to use a glider to deliver payloads for subsea installations. In this type of application, the hydrodynamic forces and dynamic stability of the glider is of particular importance, as it has implications on the glider's endurance and operation. In this work, the effect of two different wing forms, rectangular and tapered, on the hydrodynamic characteristics and dynamic stability of the glider were investigated, to determine the optimal wing form. To determine the hydrodynamic characteristics, tow tank resistance tests were carried out using a model fitted alternately with a rectangular wing and tapered wing. Steady-state CFD analysis was conducted using the hydrodynamic coefficients obtained from the tests, to obtain the lift, drag and hydrodynamic derivatives at different angular velocities. The results show that the rectangular wing provides larger lift forces but with a reduced stability envelope. Conversely, the tapered wing exhibits lower lift force but improved dynamic stability.

Effect of wing form on the hydrodynamic characteristics and dynamic stability of an underwater glider

Javaid, Muhammad Yasar,Ovinis, Mark,Hashim, Fakhruldin B.M.,Maimun, Adi,Ahmed, Yasser M.,Ullah, Barkat The Society of Naval Architects of Korea 2017 International Journal of Naval Architecture and Oc Vol.9 No.4

We are developing a prototype underwater glider for subsea payload delivery. The idea is to use a glider to deliver payloads for subsea installations. In this type of application, the hydrodynamic forces and dynamic stability of the glider is of particular importance, as it has implications on the glider's endurance and operation. In this work, the effect of two different wing forms, rectangular and tapered, on the hydrodynamic characteristics and dynamic stability of the glider were investigated, to determine the optimal wing form. To determine the hydrodynamic characteristics, tow tank resistance tests were carried out using a model fitted alternately with a rectangular wing and tapered wing. Steady-state CFD analysis was conducted using the hydrodynamic coefficients obtained from the tests, to obtain the lift, drag and hydrodynamic derivatives at different angular velocities. The results show that the rectangular wing provides larger lift forces but with a reduced stability envelope. Conversely, the tapered wing exhibits lower lift force but improved dynamic stability.

THE 2014 ALMA LONG BASELINE CAMPAIGN: OBSERVATIONS OF ASTEROID 3 JUNO AT 60 KILOMETER RESOLUTION

Hunter, T. R.,Kneissl, R.,Moullet, A.,Brogan, C. L.,Fomalont, E. B.,Vlahakis, C.,Asaki, Y.,Barkats, D.,Dent, W. R. F.,Hills, R. E.,Hirota, A.,Hodge, J. A.,Impellizzeri, C. M. V.,Liuzzo, E.,Lucas, R.,M IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.808 No.1

<P>We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum images of the asteroid 3 Juno obtained with an angular resolution of 0 ''.042 (60 km at 1.97 AU). The data were obtained over a single 4.4 hr interval, which covers 60% of the 7.2 hr rotation period, approximately centered on local transit. A sequence of 10 consecutive images reveals continuous changes in the asteroid's profile and apparent shape, in good agreement with the sky projection of the three-dimensional model of the Database of Asteroid Models from Inversion Techniques. We measure a geometric mean diameter of 259 +/- 4 km, in good agreement with past estimates from a variety of techniques and wavelengths. Due to the viewing angle and inclination of the rotational pole, the southern hemisphere dominates all of the images. The median peak brightness temperature is 215 +/- 13 K, while the median over the whole surface is 197 +/- 15 K. With the unprecedented resolution of ALMA, we find that the brightness temperature varies across the surface with higher values correlated to the subsolar point and afternoon areas and lower values beyond the evening terminator. The dominance of the subsolar point is accentuated in the final four images, suggesting a reduction in the thermal inertia of the regolith at the corresponding longitudes, which are possibly correlated to the location of the putative large impact crater. These results demonstrate ALMA's potential to resolve thermal emission from the surface of main belt asteroids and to measure accurately their position, geometric shape, rotational period, and soil characteristics.</P>