Dual Topology Research Articles

Dual topologies for the space of multi-functions

Dual topology for the function space topologies for multifunctions are introduced and investigated. It is found that a topology T on CM(Y,Z) is splitting (resp. admissible) if and only if its dual pair (T+,T?) is splitting (resp. admissible). Similarly, the pair (T+,T?) is splitting (resp. admissible) if and only if its dual T(T+,T?) is splitting (resp. admissible).

Minimum transport-driven algorithm for water distribution network partitioning

Abstract This paper presents a novel algorithm driven by the minimization of the transport function for the partitioning of water distribution networks (WDNs) into district metered areas (DMAs). The algorithm is based on the linear programming (LP) embedded inside a multi-objective genetic algorithm, which enables engineering criteria, such as the minimization of the boundary pipes and the maximization of the uniformity of DMAs, to be considered in the partitioning. Furthermore, the application of the algorithm on the dual network topology based on segments and valves guarantees that configurations of DMAs that respect the real positions of isolation valves for WDN partitioning are obtained. After being described on a small WDN, it is successfully validated on a large size WDN, proving better performance than other algorithms in the scientific literature for the generation of engineeringly appealing DMA configurations, with almost identical hydraulic performance to the unpartitioned WDN.

Research on rotor unbalance magnetic pull compensation method based on modular winding d‐axis current injection

Due to the dual air-gap topology of the direct-drive permanent magnet motor with inner enhance force (IEF-DDPMM), the radial EM exciting force generated in the inner and outer air gaps when the rotor is eccentric will act on the same rotor, and the unbalanced magnetic pull (UMP) on the rotor will reduce the fatigue life of the rotor structure and bring many problems such as vibration and noise. Therefore, the rotor UMP compensation method of IEF-DDPMM based on modular winding d-axis current injection is proposed to suppress the harm caused by eccentricity. The expression of electromagnetic (EM) exciting force considering the cogging effect and current time harmonic without rotor eccentricity faults is derived by the analytical method. Also, the EM exciting force newly introduced due to the rotor eccentricity is analysed. The effects of different eccentricity types on torque characteristics, the fatigue life of the rotor structure and stator vibration of IEF-DDPMM are compared and analysed by the FEM. Finally, the IEF-DDPMM rotor eccentricity models are optimised based on the method. The performance of the motor before and after rotor UMP compensation is evaluated by FEM. The results show that the proposed method is correct and effective.

PV-based Grid Interactive PMBLDC Electric Vehicle with High Gain Interleaved DC-DC SEPIC Converter

In recent times, the prominence of permanent magnet BLDC motor is highly proliferating in all domestic, commercial, and industrial appliances, including the electric vehicle (EV) drives. The present research explicates the interfacing of a solar panel and grid with the electric vehicle like electric train. To produce higher dc voltage with a negligible switching loss, a novel interleaved SEPIC converter is employed in this study since can operate at low duty cycle. The output of the converter is associated with the BLDC motor-fed electric train and grid through a three-phase and single-phase inverters, respectively. The switching action of the inverter is controlled by a PI controller. During the daytime, the obtained output of PV is supplied to the electric train and grid, through which the solar power is fully used without any wastage, but at the night time, the power is supplied from the grid to EV through a converter. Thus the dual source topology with a single converter configuration is achieved. This low loss drive system requires no battery arrangements, which makes it simple and cost effective. The operation of the proposed converter is simulated in MATLAB and the test results are validated with the experimental prototype setup.

PyAutoFEP: An Automated Free Energy Perturbation Workflow for GROMACS Integrating Enhanced Sampling Methods.

Free energy perturbation (FEP) calculations are now routinely used in drug discovery to estimate the relative FEB (RFEB) of small molecules to a biomolecular target of interest. Using enhanced sampling can improve the correlation between predictions and experimental data, especially in systems with conformational changes. Due to the large number of perturbations required in drug discovery campaigns, the manual setup of FEP calculations is no longer viable. Here, we introduce PyAutoFEP, a flexible and open-source tool to aid the setup of RFEB FEP. PyAutoFEP is written in Python3, and automates the generation of perturbation maps, dual topologies, system building and molecular dynamics (MD), and analysis. PyAutoFEP supports multiple force fields, incorporates replica exchange with solute tempering (REST) and replica exchange with solute scaling (REST2) enhanced sampling methods, and allows flexible λ values along perturbation windows. To validate PyAutoFEP, it was applied to a set of 14 Farnesoid X receptor ligands, a system included in the drug design data resource grand challenge 2. An 88% mean correct sign prediction was achieved, and 75% of the predictions had an error below 1.5 kcal/mol. Results using Amber03/GAFF, CHARMM36m/CGenFF, and OPLS-AA/M/LigParGen had Pearson's r values of 0.71 ± 0.13, 0.30 ± 0.27, and 0.66 ± 0.20, respectively. The Amber03/GAFF and OPLS-AA/M/LigParGen results were on par with the top grand challenge 2 submissions. Applying REST2 improved the results using CHARMM36m/CGenFF (Pearson's r = 0.43 ± 0.21) but had little impact on the other force fields. CHARMM36-YF and CHARMM36-WYF modifications did not yield improved predictions compared to CHARMM36m. Finally, we estimated the probability of finding a molecule 1 pKi better than a lead when using PyAutoFEP to screen 10 or 100 analogues. The probabilities, when compared to random sampling, increased up to sevenfold when 100 molecules were to be screened, suggesting that PyAutoFEP would likely be useful for lead optimization. PyAutoFEP is available on GitHub at https://github.com/lmmpf/PyAutoFEP.

Dummy Atoms in Alchemical Free Energy Calculations.

In calculations of relative free energy differences, the number of atoms of the initial and final states is rarely the same. This necessitates the introduction of dummy atoms. These placeholders interact with the physical system only by bonded energy terms. We investigate the conditions necessary so that the presence of dummy atoms does not influence the result of a relative free energy calculation. On the one hand, one has to ensure that dummy atoms only give a multiplicative contribution to the partition function so that their contribution cancels from double-free energy differences. On the other hand, the bonded terms used to attach a dummy atom (or group of dummy atoms) to the physical system have to maintain it in a well-defined position and orientation relative to the physical system. A detailed theoretical analysis of both aspects is provided, illustrated by 24 calculations of relative solvation free energy differences, for which all four legs of the underlying thermodynamic cycle were computed. Cycle closure (or lack thereof) was used as a sensitive indicator to probing the effects of dummy atom treatment on the resulting free energy differences. We find that a naive (but often practiced) treatment of dummy atoms results in errors of up to kBT when calculating the relative solvation free energy difference between two small solutes, such as methane and ammonia. While our analysis focuses on the so-called single topology approach to set up alchemical transformations, similar considerations apply to dual topology, at least many widely used variants thereof.

Multi-physics design and analyses of dual rotor synchronous reluctance machine

Dual rotor topology of synchronous reluctance machine is here proposed to improve the motor torque density and reduce the torque ripple. Thus, allowing synchronous reluctance machine to merge into EV and HEV applications. This paper presents a multi-physics design and analyses of three double rotor synchronous reluctance machine, 24/4, 36/4 and 48/4 stator slot/rotor pole combinations, through electromagnetic, mechanical and thermal analysis. First, a genetic algorithm optimization process linked to magnetic FEA has been used. The optimization is set to target the highest torque, lowest torque ripple and core loss. Mechanical study and investigation of the magnetic and rotational forces on the rotor ribs and stator tooth-tip structure have been considered to guarantee the mechanical robustness. Furthermore, the design assembly structure to ease heat dissipation from the stator has been investigated thermally. Finally, a comparison with a conventional single-rotor synchronous reluctance machine having the same size and operating conditions have been made to highlight the advantages of the double rotor synchronous reluctance machine. From the comparison it has been concluded that the double rotor machine produced 45% higher torque and 40% less torque ripple compared to its single rotor counterpart. Synchronous Reluctance Machines, Double Rotor Machine, Structural Analysis, Double Airgap Machines. • The design of a novel double rotor synchronous reluctance machine is presented. • A multi-physics design process and genetic algorithm global optimization are used. • The double rotor machine showed higher power density when compared to the single rotor. • Lower torque ripple is found in the double rotor machine when compared to the single rotor. • The higher power density and lower torque ripple are essential for automotive application.

A study of topological structures on equi-continuous mappings

Function space topologies are developed for EC(Y,Z), the class of equi-continuous mappings from a topological space Y to a uniform space Z. Properties such as splittingness, admissibility etc. are defined for such spaces. The net theoretic investigations are carried out to provide characterizations of splittingness and admissibility of function spaces on EC(Y,Z). The open-entourage topology and pointtransitive-entourage topology are shown to be admissible and splitting respectively. Dual topologies are defined. A topology on EC(Y,Z) is found to be admissible (resp. splitting) if and only if its dual is so.

Elucidation of the dimeric interplay of dual MRAP2 proteins in the zebrafish.

The melanocortin receptor accessory protein 2 (MRAP2) plays an essential role in the regulation of metabolic homeostasis and deletion of which results in severe obesity syndrome in mice and human. Mammalian MRAP2 is recognized as an endogenous physiological mediator through the potentiation of the MC4R signaling in vivo. Two isoforms of MRAP2 are identified in zebrafish genome, zMRAP2a and zMRAP2b. However, the mechanism of assembling dual topology and the regulatory roles of each complex on the melanocortin cascades remains unclear. In this study, we showed the bidirectional homo- and hetero-dimeric topologies of two zebrafish MRAP2 isoforms on the plasma membrane. Orientation fixed chimeric proteins could affect the trafficking and pharmacological properties of zMC4R signaling. Reciprocal replacement of zMRAP2a and zMRAP2b proteins elucidated the major participation of the carboxyl terminal as the functional domain for modulating zMC4R signaling. Our findings revealed the complex and dynamic conformational regulation of dual zebrafish MRAP2 proteins in vitro.

Evolution of Inverted Repeats in Membrane Transporters

The majority of membrane transport proteins of known structure exhibit internal repeat symmetry, with two or more structurally homologous domains. inverted repeat architecture, where the domains are antiparallel with respect to each other, is especially common. This architecture implies the existence of ancestral monomeric proteins that form dual-topology antiparallel dimers, before duplication and fusion led to the extant inverted repeat forms. The Fluc family of fluoride channels is the first family to be discovered that connects these two evolutionary extremes, with both dual topology and inverted repeat representatives. Here we use the Fluc family of fluoride channels to model genetic drift in a newly duplicated membrane protein. Using fluoride resistance assays, we pursue a deep mutational scan to describe how evolutionary forces like mutational robustness and paralogue interference play out after the duplication of single-domain membrane proteins. We connect these experiments to phylogenetic observations of the Fluc superfamily.

Biophysical Characterization and Structural Studies of Small Multidrug Resistance Family of Transporters

The Small Multidrug Resistance (SMR) family of membrane proteins is known for conferring resistance to a wide range of antibiotics and xenobiotic compounds in bacteria. Moreover, their small size and rare dual topology architecture have made them a suitable model system for studying membrane protein mechanism and evolution. Despite many years of research on multidrug exporters in the SMR family, the family's main function has remained a mystery. We show for the first time, using phylogenetic studies and membrane transport assays, that the majority members of this family are not drug exporters.

Modeling and control of DC/AC converters for photovoltaic grid-tie micro-inverter application

• Modeling and control for a Photovoltaic-based microinverter system. • An efficient maximum power point tracking algorithm is implemented here. • Both state-space modeling and small-signal analysis are carried out. • Enhancement of transient and dynamic performance by using a cascaded controller. • Finally, a 500 Watts, 110 V, 50 Hz microinverter prototype is fabricated and tested. This paper is devoted to the modelling and control for a low cost, high-power quality single-phase voltage source inverter (VSI) for a grid-tied PV-based micro-inverter system. The first stage includes a high-efficiency isolated boost dual half-bridge dc-dc converter topology which interfaces to the PV panel and produces a dc-link voltage. The second stage is comprised of a single-phase VSI circuit. A state-space average model for a 1-Φ VSI with low-pass LCL filter topology has been developed. The steady-state and dynamic performance of the system can be improved by using three cascaded control loops. The fast inner current controller is adopted to regulate the inductor current of the inverter thereby improved dynamic response of the system. The small-signal analysis is conducted to assess the robustness of the proposed controller. An outer dc bus voltage control loop is employed to keep the constant voltage across the dc-bus capacitor. Next, the grid-side current loop is employed to regulate the grid current with a low total harmonic distortion level. The Bode-diagrams are plotted to assess the stability of each control loops. Finally, a 500 Watts, 110 V, 50 Hz micro-inverter prototype is fabricated and tested. The simulation and experimental results are given to show the effectiveness of the proposed control scheme.

Modified LUO High Gain DC-DC Converter With Minimal Capacitor Stress for Electric Vehicle Application

The vigorous growth of electric vehicles in the field of automobile paves the way for the development of dc-dc converter. A novel high gain super Luo dc-dc converter is proposed in this article. A modification is suggested in the topology when the converters are cascaded for high gain. This suggested modification can be applied to any topology for reliable capacitor. The presented converter adds boosting (voltage multiplier) cell before the load to expand the voltage conversion ratio. This converter renders remarkable features like extended voltage gain, low voltage stress on power switches, minimal capacitor stress and less component count. The operating principle and steady-state analysis of the proposed topology is presented. The main feature of the proposed topology is reduced capacitor stress which is evaluated by reliability study with military handbook MIL-HDBK-217F. The significance of minimal capacitor stress with the failure of the capacitor is elaborated. Simulation on the derived topology is carried out with Matlab/Simulink and it validates the theoretical results. Furthermore, the proposed topology is extended with dual output which makes the restructured converter suitable for Electric vehicle application and the simulation of the dual output topology is performed and studied. The experimental results obtained from the 50 W prototype validate the complete steady-state analysis performed on the proposed topology.

Design and Analysis of Wideband Rectenna for IoT Applications

This work addresses the design analysis of a wideband rectifier for the broadband frequencies at 1GHz to 5GHz. In the paper, a new broadband antenna with a compact rectifier circuit is analyzed. Here, two types of rectifier circuits are analyzed: First rectifier circuit with HSMS series HSMS 270B Schottky diode and Second circuit with MOTOROLA series 5456a diode. Comparative analysis of both the circuit is also shown. Dual diode topology is introduced to enhance the performance of rectenna (Antenna with Rect ifier) in terms of power conversion efficiency (PCE). According to the simulation it shows, the second rectifier circuit with a proposed antenna shows a better efficiency response. From this device observed RF power at the output is 16.599dBm, 45.7mW, and 70.58% PCE at 0dBm input power. The proposed rectenna enables the power supply of low-power IoT devices that require the minimum power required to operate.

Performance Improvement of Dual Stator Axial Flux Spoke Type Permanent Magnet Vernier Machine

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.

Dual Radiator Based Low Profile Fan Beam Antenna for Millimeter Wave Fencing System

The paper describes the design, development, and characterization of a low profile, lightweight and linearly polarized fan beam radiating array antenna for millimeter wave fencing system. Dual antenna topology has been proposed for each transmit and receive tower to obtain maximum coverage area compared to a single antenna configuration. The radiator placement (height) has been optimized to minimize the dead zone region. Proposed RF fencing system utilizes an 8x32 probe-fed microstrip patch array antenna developed on 10 mils RT Duroid dielectric substrate material. ANSYS's High-Frequency Structure Simulator (HFSS) full-wave EM software has been utilized for simulation and analysis of designed radiating array. VSWR of the realized antenna is 1.75:1 over the frequency band of 34.5 GHz to 35.5 GHz. The E-plane and H-plane HPBW of the developed antenna at 35 GHz is 8.4 and 2.2 degrees respectively. The measured gain of the antenna is better than 25.4dBi over the frequency band 34.5 GHz to 35.5 GHz.

Development and Analysis of a Dual Input Buck-Boost DC-DC Converter Topology for Hybrid Energy Applications

In this Paper, a Dual Input buck - boost DC-DC (DIDC) converter is introduced for the integration of two input energy sources. The converter is capable of integrating energy sources which have different V-I characteristics. The output equation of the DIDC converter is derived from different working states using voltage - second principle. The voltage and current stress analysis of the converter are also carried out. The detailed study of the converter is conducted in the MATLAB/Simulink platform and the results are validated through laboratory experiments.

An Integration of dual UPQC controller for power quality compensation by extending its voltage regulation at grid side as a STATCOM

This paper presents a modified controller by integrating dual unified power quality conditioners: iUPQC controller with its utilization in microgrid and power-quality utilizations. By applying this regulatory controller it extends the quality of power characteristics just like the UPQC controller it offers reactive power regulation both at load-side bus voltage and at grid-side bus voltage, which also compensates voltage swell & sag. At grid-side iUPQC controller will work as a STATCOM, by providing all the conventional UPQC applications both at the grid-side and load-side. Simulink consequences are providing to validate the latest predictability of the apparatus. Index Terms: Dual topology: iUPQC, unified power quality conditioner (UPQC), power quality, micro grids, STATCOM-static synchronous compensator.

The structural basis of promiscuity in small multidrug resistance transporters

By providing broad resistance to environmental biocides, transporters from the small multidrug resistance (SMR) family drive the spread of multidrug resistance cassettes among bacterial populations. A fundamental understanding of substrate selectivity by SMR transporters is needed to identify the types of selective pressures that contribute to this process. Using solid-supported membrane electrophysiology, we find that promiscuous transport of hydrophobic substituted cations is a general feature of SMR transporters. To understand the molecular basis for promiscuity, we solved X-ray crystal structures of a SMR transporter Gdx-Clo in complex with substrates to a maximum resolution of 2.3 Å. These structures confirm the family’s extremely rare dual topology architecture and reveal a cleft between two helices that provides accommodation in the membrane for the hydrophobic substituents of transported drug-like cations.

Single-Stage Hybrid Energy Storage Integration in Electric Vehicles Using Vector Controlled Power Sharing

The dual inverter topology driving an open-winding motor is well known in high voltage motor drive applications. This structure allows two energy sources to be directly connected to an open-winding motor. This enables the integration of supercapacitors into a battery electric vehicle (EV). Unlike existing solutions, this article demonstrates dynamic power sharing between the dual energy sources by controlling the active and reactive voltages of the twin inverters, thus enabling the use of the supercapacitor for either active power assist and/or reactive power assist. The dedicated vector-controlled power sharing method and energy management is shown to achieve power sharing in the dual inverter drive integrating a battery and supercapacitor, thereby eliminating the need for an additional cascaded dc/dc converter to extract/supply energy to the supercapacitor. It also enables improved efficiency by eliminating switching losses in the supercapacitor inverter during low power operation. The proposed voltage vector splitting method is also shown to achieve battery-to-supercapacitor power exchange for regulating the net energy in the supercapacitor without affecting motor operation. A laboratory prototype utilizing a 110-kW liquid-cooled EV motor and supercapacitor bank is developed to verify the practical implementation of the power and energy management strategy.