control stability
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2021 ◽  
Vol 13 (1) ◽  
pp. 2
Author(s):  
Houssein Al Attar ◽  
Mohamed Assaad Hamida ◽  
Malek Ghanes ◽  
Miassa Taleb

Electric Vehicle (EV) bidirectional charger technology is growing in importance. It defines the fact of returning the electricity stored in the batteries of EV to Grid (V2G), to Home (V2H), to Load (V2L), or in one word V2X mode. The EV onboard charger is divided into two parts: AC-DC and DC-DC converters. The isolated bidirectional DC-DC LLC resonant converter is used to improve the charger efficiency within both battery power and voltage ranges. It is controlled by varying the switching frequency based on a small signal modeling approach using the gain transfer function inversion method. The dimensions of the DC-DC LLC converter directly affect the charger cost. Moreover, they cause an important control frequency saturation zone, especially in V2X mode, where the switching frequency is out of the feasibility zone. The new challenge in this paper is to design an optimization strategy to minimize the LLC converter cost and improve the control frequency feasibility zone, for a wide variation of battery voltage and converter power, in the charging (G2V) and discharging (V2X) modes simultaneously. For our best knowledge, this optimization problem, in the case of a bidirectional (G2V and V2X) charger, is not yet considered in the literature. An optimal design that considers the control stability equations in the optimization algorithm is elaborated. The obtained results show a significant converter cost decrease and important expansion of control frequency feasibility zones. A comparative study between initial and optimized values, in G2V and V2X modes, is generated according to the converter efficiency.


Author(s):  
Illuru Sree Lakshmi

Abstract: An islanding detection and based control strategy is created in this exploration to accomplish the steady and independent activity of microgrids using the neural network based Virtual Synchronous Generator (VSG) idea during unplanned grid reconfigurations . Maybe of utilizing a design-orientedmethodology, this paper gives a rigorous and extensive hypothetical investigation and reaches a concise conclusion that is easy to execute and successful even in complex situations. Based on the results of the mutation sequence and voltage wavering, a neural network based islanding identification calculation is proposed, which requires less constraint strategy. The proposed neural network approach outperforms the thefrequency measured passive detection method in terms of detection speed and reliability. Broad recreations affirm the reasonableness of the proposed islanding location and control methodology. Additionally, think about the results of the reproductions for the PI regulator, fluffy organizations, and neural organizations. Keywords: Virtual Synchronous Generator, Islanding detection, Islanding operation, Droop control, Stability, Microgrids.


Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1560
Author(s):  
Estanislao Navarro ◽  
Adrián Mallén ◽  
Miguel Hueso

This paper concerns 3′-untranslated regions (3′UTRs) of mRNAs, which are non-coding regulatory platforms that control stability, fate and the correct spatiotemporal translation of mRNAs. Many mRNAs have polymorphic 3′UTR regions. Controlling 3′UTR length and sequence facilitates the regulation of the accessibility of functional effectors (RNA binding proteins, miRNAs or other ncRNAs) to 3′UTR functional boxes and motifs and the establishment of different regulatory landscapes for mRNA function. In this context, shortening of 3′UTRs would loosen miRNA or protein-based mechanisms of mRNA degradation, while 3′UTR lengthening would strengthen accessibility to these effectors. Alterations in the mechanisms regulating 3′UTR length would result in widespread deregulation of gene expression that could eventually lead to diseases likely linked to the loss (or acquisition) of specific miRNA binding sites. Here, we will review the mechanisms that control 3′UTR length dynamics and their alterations in human disorders. We will discuss, from a mechanistic point of view centered on the molecular machineries involved, the generation of 3′UTR variability by the use of alternative polyadenylation and cleavage sites, of mutually exclusive terminal alternative exons (exon skipping) as well as by the process of exonization of Alu cassettes to generate new 3′UTRs with differential functional features.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6899
Author(s):  
Fisnik Loku ◽  
Patrick Düllmann ◽  
Christina Brantl ◽  
Antonello Monti

A major challenge in the development of multi-vendor HVDC networks are converter control interactions. While recent publications have reported interoperability issues such as persistent oscillations for first multi-vendor HVDC setups with AC-side coupling, multi-terminal HVDC networks are expected to face similar challenges. To investigate DC-side control interactions and mitigate possible interoperability issues, several methods based on the converters’ and DC network’s impedances have been proposed in literature. For DC network’s impedance modelling, most methods require detailed knowledge of all converters’ design and controls. However, in multi-vendor HVDC networks, converter control parameters are not expected to be shared due to proprietary reasons. Therefore, to facilitate impedance-based stability analyses in multi-vendor MTDC networks, methods that do not require the disclosure of the existing converter controls are needed. Here, detailed impedance measurements can be applied; however, they are time-consuming and require new measurement for a single configuration change. This paper proposes an equivalent impedance calculation method suitable for multi-vendor DC networks, which for available black-box models or converter impedance characteristics can be modularly applied for various network configurations, including different control settings and operating points, while significantly reducing the required time for obtaining an equivalent DC network impedance.


2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A1-A1
Author(s):  
T Altree ◽  
A Aishah ◽  
K Loffler ◽  
R Grunstein ◽  
D Eckert

Abstract Introduction Noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. Selective norepinephrine reuptake inhibitors (SNRIs) such as reboxetine combined with an antimuscarinic reduce obstructive sleep apnea (OSA) severity. The effects of reboxetine alone on OSA severity are unknown. Methods Double-blind, placebo-controlled, three-way crossover trial in 16 people with OSA. Each participant completed three overnight polysomnograms (~1-week washout). Single doses of reboxetine 4mg, placebo, or reboxetine+oxybutynin 5mg were administered before sleep (randomized order). The primary outcome was apnea-hypopnea index (AHI). Secondary outcomes included other polysomnography parameters, next day sleepiness and alertness. Endotyping analysis was performed to determine the medications’ effects on OSA pathophysiological mechanisms. Results Reboxetine reduced the AHI by 5.4 [95% CI -10.4 to -0.3] events/h, P=0.03 (men: -24±27%; women: -0.7±32%). The addition of oxybutynin did not further reduce AHI. Reboxetine alone and reboxetine+oxybutynin reduced overnight hypoxemia versus placebo (e.g. 4% oxygen desaturation index 10.4±12.8 vs. 10.6±12.8 vs. 15.7±14.7 events/h, P=0.02). Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control stability. Men had higher baseline loop gain. Larger reductions in AHI with reboxetine occurred in those with high loop gain. Neither drug intervention changed next day sleepiness or alertness. Discussion A single 4mg dose of reboxetine modestly reduces OSA severity without further improvement with the addition of an antimuscarinic. Reboxetine increases breathing stability via improvements in pharyngeal collapsibility and respiratory control. These findings provide new insight into the role of SNRIs on upper airway stability during sleep and have important implications for pharmacotherapy development for OSA.


Actuators ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 252
Author(s):  
Nathir Rawashdeh ◽  
Nader Abu-Alrub

In this work, a design of a gripper for the underwater OpenROV vehicle is presented. OpenROV is an open-source underwater vehicle design for remote underwater exploration. It can enable systems of underwater internet of things and real-time monitoring. Mechanical aspects of the presented gripper design are discussed including actuation, motion transmission, kinematics and general arrangement, which resembles a delta robot. The Denavit-Hartenberg (DH) notation will be employed to define reference frames on one of the fingers in order to build transformation matrices and the forward kinematics matrix. The results from the forward kinematics are used to define the workspace that can be covered by each finger. The maximum force from the fingertip is estimated using Newton-Euler equations. Finally, the transfer function and the mass moment of inertia of the second link in the finger, that is, the fingertip is calculated for control simulations. A control stability analysis is provided and shows a stable system.


2021 ◽  
Vol 118 (40) ◽  
pp. e2111391118
Author(s):  
Thang Van Nguyen

Targeted protein degradation by the ubiquitin–proteasome system represents a new strategy to destroy pathogenic proteins in human diseases, including cancer and neurodegenerative diseases. The immunomodulatory drugs (IMiDs) thalidomide, lenalidomide, and pomalidomide have revolutionized the treatment of patients with multiple myeloma (MM) and other hematologic malignancies, but almost all patients eventually develop resistance to IMiDs. CRBN, a substrate receptor of CUL4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase, is a direct target for thalidomide teratogenicity and antitumor activity of IMiDs (now known as Cereblon E3 ligase modulators: CELMoDs). Despite recent advances in developing potent CELMoDs and CRBN-based proteolysis-targeting chimeras (PROTACs), many questions apart from clinical efficacy remain unanswered. CRBN is required for the action of IMiDs, but its protein expression levels do not correlate with intrinsic resistance to IMiDs in MM cells, suggesting other factors involved in regulating resistance to IMiDs. Our recent work revealed that the CRL4CRBN-p97 pathway is required for degradation of natural substrate glutamine synthetase (GS) and neosubstrates. Here, I show that USP15 is a key regulator of the CRL4CRBN-p97 pathway to control stability of GS and neosubstrates IKZF1, IKZF3, CK1-α, RNF166, GSPT1, and BRD4, all of which are crucial drug targets in different types of cancer. USP15 antagonizes ubiquitylation of CRL4CRBN target proteins, thereby preventing their degradation. Notably, USP15 is highly expressed in IMiD-resistant cells, and depletion of USP15 sensitizes these cells to lenalidomide. Inhibition of USP15 represents a valuable therapeutic opportunity to potentiate CELMoD and CRBN-based PROTAC therapies for the treatment of cancer.


2021 ◽  
Vol 5 (1) ◽  
pp. 3-13
Author(s):  
Gabriela Teixeira ◽  
Stacy Ondina ◽  
Alexandre Bella Cruz ◽  
Tania Mari Bellé Bresolin

Acne affects most young people and its topical treatment with antibacterials is associated with increased bacterial resistance to antibiotics and adverse effects. As an alternative, ozone therapy stands out through the application of ozonized oils. The objective of this work was to raise the scientific evidence about the effectiveness in the treatment of acne, in addition to the techniques of characterization and stability of ozonated oils. This is an exploratory, descriptive study with a quantitative approach, based on the analysis of scientific references in a bibliographic review of the expository type, of the last 20 years. Among the selected references, only four manuscripts reporting clinical studies of ozone therapy, with controversial results. Seven articles with the physicochemical characterization of ozonated oils were found. The major part of manuscripts reported the use of sunflower, sesame and olive oil. The more common techniques used to characterize the ozonation process are the peroxide value (PV) and the iodine index (Ii), which represents the proportion of unsaturated groups, whose values increase and decrease, respectively with ozonization progress. The viscosity of oils is increased by the formation of polymeric peroxides; the FTIR spectrum, which identifies the decrease in the stretch bands C = C, in addition to ozone formation, monitored by NMR, are also employed. Increased antimicrobial activity has been demonstrated with the ozone level of the oils, but the activity against Cutibacterium acne has not been reported. Only two article reported satisfactory stability for 6 months of refrigerated ozonized oil or kept at room temperature, showing the need for more specific research to support the application of ozonized oils in the treatment of acne and stability data of these products.


2021 ◽  
pp. 26-41
Author(s):  
Yu. Romasevych ◽  
◽  
V. Loveikin ◽  
A. Shevchuk ◽  
I. Bolbot ◽  
...  

In the article, experimental studies of the neurocontroller of a laboratory installation of a quadrocopter link are presented. The latter is a nonlinear dynamic system. The input vector of the neurocontroller included the angle of inclination of the rod (a beam of the quadcopter) relative to the horizon, its angular velocity, and the angular velocity of the propeller. The output signal of the neurocontroller is proportional to the supply voltage of the propeller drive. In the article, the planning of experimental studies was carried out and eight indicators were selected, according to which the quality of the control process was evaluated. In addition, a qualitative analysis of the control process of the dynamic system motion was carried out with the corresponding graphical dependencies. The data obtained showed a good quality of control at a zero setpoint angle. For other values of the setpoint (-0.52 and -1.05 rad), the neurocontroller provides the rod aboutness to the setpoint angle and the control stability. However, the quality of control is not high. The reason for this effect has been established in the work. In order to improve the quality of control, the neurocontroller was modified by including an integral component in its structure. At the same time, the steady-state control error has significantly decreased with minor changes in other estimated indicators.


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