Stage Configuration Research Articles

Resilience enhancement of Islanded Microgrid by diversification, reconfiguration, and DER placement/sizing

Motivated by recent wide-scale deployment of Microgrids (MGs), this paper proposes an innovative framework for resilience enhancement of Islanded Microgrids (IMGs) against potential cyberattacks targeting IMG’s critical load curtailment. The proposed framework provides solutions for resilience enhancement in pre-attack (normal situation) and post-detection stages benefiting from three techniques, i.e., (i) ODPS: Optimal Distributed Energy Resources (DER) Placement and Sizing, (ii) OID: Optimal Intelligent Electronic Devices (IED) Diversification, and (iii) OPNR: Optimal Power Network Reconfiguration. The proposed approach improves all the phases of the resilience curve for an IMG, i.e., survive, sustain, and recovery. To improve the survive and sustain resilience phases, ODPS and OID techniques are used to optimally design the power and cyber configurations in pre-attack stage. In the operation phase, an OPNR technique is employed in both pre-attack and post-detection stages to effectively enhance the system resilience in survive and recovery phases. The effectiveness of the proposed approach is evaluated using IEEE 17- and 69-bus test systems operating as IMGs. The obtained results demonstrate significant improvements in the overall resilience of the underlying IMG.

3.3 kW narrow linewidth FBG-based MOPA configuration fiber laser with near-diffraction-limited beam quality

This paper demonstrates a narrow-linewidth fiber laser with near-diffraction-limited beam quality and high Raman suppression ratio by utilizing Master Oscillator Power-Amplifier structure based on narrow-bandwidth fiber Bragg gratings. The output power reaches 3.31 kW with a slope efficiency of 85.0 %. At the maximum output power, the 3 dB, 10 dB, and 20 dB linewidths are 0.40 nm, 1.20 nm, and 3.09 nm, respectively. The beam quality M2 factor is 1.32 and the Raman suppression ratio reaches 26.3 dB. A pair of narrow-bandwidth fiber gratings were used in the oscillator to compress the linewidth of the seed laser. We used backward-pumping configuration and plum-coiled gain fiber in the amplification stage to suppress the Raman effect and select transverse mode by fiber-bending. Finally, a compact all-fiber laser was obtained with narrow-linewidth, high beam quality, and effective suppression of the Raman effect. To the best of our knowledge, this is the highest output power for a sub-nanometer-linewidth laser using narrow-bandwidth fiber gratings and none-wavelength-locked laser diodes, which achieves near-diffraction-limit beam quality. This provides a solution for high-power narrow-linewidth laser sources with high beam quality.

Performance Estimation and Design Optimization of a Congested Automated Container Terminal

Container terminal capacity, as an important indicator of container terminal competitiveness, has become a primary concern of port managers, whereas container flows, which are supported by quay cranes, yard cranes, and automated guided vehicles, have a substantial influence on container terminal capacity. Container flows are analyzed in this article to estimate the performance of an automated container terminal considering traffic congestion, unbalanced task assignment, container batch arrival, and different berth and yard layouts. The operating system is formulated as a closed-queuing network with four stations. Theoretical analysis and the solution method are adopted to determine system capacity. The resource allocation and system design, specifically the number of vehicles, berth and yard layouts, and task assignment strategy, are optimized. Numerical experiments are conducted to provide management insights into port capacity planning, resource optimization, and layout design. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The construction of an automated container terminal (ACT) requires a sizable investment. Analyzing the performance of the container terminal with different configurations in the planning stage, which is before the construction of ports, is very important. Thus, planners can select better resource configurations. Generally, simulation is an intuitive way to estimate performance. However, formulating and running the simulation model with different configurations is time consuming. An analytic model for estimating the performance of an ACT is developed to reduce computational time in this article.

Economic Analysis of Membrane-Based Separation of Biocatalyst: Mode of Operation and Stage Configuration

Economic Analysis of Membrane-Based Separation of Biocatalyst: Mode of Operation and Stage Configuration

A Reduced Stage Configuration of Three-Phase Isolated AC/DC Converter for Auxiliary Power Units

This paper presents a reduced-stage three-phase isolated AC/DC converter topology used for auxiliary power units (APUs) in avionics and electric vehicle (EV) applications. Traditional two-stage cascaded AC/DC converters are widely used for these applications due to their ease of implementation and simple control schemes. With the objective of improving the power density of the APUs, the proposed converter achieves reduction in the number of active power devices along with a smaller DC link capacitance by implementing an unconventional structure with a bandpass filter, to allow only the required frequency components to transfer the rated power. To accurately characterize the proposed converter, a detailed formulation of the filter design for the circuit along with mathematical derivation of the control scheme is presented. In terms of achieving enhancement in the overall efficiency, a comparative study is presented that focusses on the conduction and switching losses incurred in the proposed topology as compared to the state of the art (SOA) two-stage AC/DC conversion topologies. The analyses portray efficiency improvement of 0.8% for a 6 kW rated load, with significant reduction in active device losses. Additionally, to support the formulations and derivations, simulation studies and experimental verifications are also presented. The results show an input power factor of 0.9918 (lagging) with a conversion efficiency of 97.6%, a tightly regulated output voltage with less than 1% peak-peak ripple and the input current total harmonic distortion (THD) of as low as 1.57%.

The Circus-Theater of Albacete: Acoustic characterization and analysis of its double stage configuration

A circus-theater is a particular type of theater space. It is mainly characterized by the possibility of interchanging the typical configuration of theater, where the stage house is settled in quasi-circularly to the audience area, to a circus configuration, in which the stage is totally surrounded by the audience area. Despite the abundant literature that tries to objectively and subjectively assess the acoustic characteristics of several theater spaces, there is scarce information about the acoustics of circus-theaters.This work is a first approach to the acoustic characterization of such theater spaces. The main goal of this paper is to acoustically evaluate a circus-theater; for that, objective “in situ” measurements have been carried out considering both stage configurations. ISO 3382-1 has been taken as the guidance to select the acoustic parameters to measure, together with some other well-known additional parameters of room acoustics.Measurements and characterization processes have been applied to the Circus-Theater of Albacete, as this is one of the few Spanish circus-theaters that still offers the possibility of using both stage configurations. Results allow to acoustically characterize a preliminary description of this kind of theater spaces, as well as comparatively study the theater and circus configurations from an acoustic point of view.

A Code for the Preliminary Design of Cooled Supercritical CO2 Turbines and Application to the Allam Cycle

Abstract This paper documents a thermo-fluid-dynamic mean-line model for the preliminary design of multistage axial turbines with blade cooling applicable to supercritical CO2 turbines. Given the working fluid and coolant inlet thermodynamic conditions, blade geometry, number of stages and load criterion, the model computes the stage-by-stage design along with the cooling requirement and ultimately provides an estimate of turbine efficiency via a semi-empirical loss model. Different cooling modes are available and can be selected by the user (stand-alone or combination): convective cooling, film cooling, and thermal barrier coating. The model is applied to attain the preliminary aero-thermal design of the 600 MW cooled axial supercritical CO2 turbine of the Allam cycle. Results show that a load coefficient varying from 3 to 1 throughout the machine, and a reaction degree ranging from 0.1 to 0.5 lead to the maximum total-to-static turbine efficiency of about 85%. Consequently, as opposed to uncooled CO2 turbines, a repeated stage configuration is an unsuited design choice for cooled sCO2 machines. Moreover, the study highlights that film cooling is considerably less effective compared to conventional gas turbines, while increasing the number of stages from 5 to 6 and adopting higher rotational speeds leads to an increased efficiency.

Recognition Rate Versus Substitution Rate Curve: An Objective Utility Assessment Criterion of Simulated Training Data

Data augmentation is beneficial when the measured training data are insufficient to train a robust deep model. One of the promising techniques is to use simulated data generated by physics-based engines. For example, few-shot learning of synthetic aperture radar (SAR) targets could be benefited from simulated SAR images. However, the characteristics of the simulated training data significantly affect the performance of the trained model. Therefore, it is of great significance to evaluate the utility of simulated data objectively and effectively. A recognition rate versus substitution rate curve (RSC)-based assessment criterion is proposed, consisting of substitution rate (SR)-based dataset allocation stage and RSC-based evaluation stage. First, the differential dataset allocation is performed under a progressive SR to obtain paired reference and comparison training sets. Then, the reference and comparison classifiers are trained under different SRs using the same network and parameter configuration in the RSC criterion-based evaluation stage. AconvNet and AlexNet are selected as the backbones of the evaluation network. Especially, k-fold cross-validation is applied to alleviate selection bias. The difference between the integrals of RSCs is defined as the RSC score for the simulated dataset. Experiments conducted on the measured and simulated moving and stationary target acquisition and recognition (MSTAR) database demonstrate the rationality and validity of the proposed RSC criterion. Specifically, multisource simulated datasets are adopted, including the adversarial autoencoder-generated and electromagnetic simulation datasets. The proposed RSC criterion shows promising utility evaluation ability, flexibility, and extensibility compared with traditional full-reference image-quality assessment criteria.

Design of cascade thermoelectric generation systems with improved thermal reliability

This paper presents a comprehensive analysis of novel, unileg cascade thermoelectric systems. Unileg systems offer the flexibility of selecting a single (p- or n-) thermoelectric material in a thermoelectric system compared to two (n- and p-) materials. Finite element analysis simulations were performed to design and analyze two and three stages of cascade systems. Simulation results show that unileg cascade systems perform significantly (∼75%) better than their unicouple counterparts in both two and three stage configurations due to the elimination of the poorly performing thermoelectric leg. In addition to the enhanced thermoelectric power generation, thermal stress is lowered in unileg systems since the mismatch of the thermal expansion coefficient originating between different TE legs material can be minimized. Overall, the presented unileg systems show their promise for the future thermoelectric energy generation or cooling applications for electronics.

Smart Hydrant Monitoring System Prototype

In this article, we will develop a system that allows the monitoring of hydrants through an Arduino microcontroller in the city of Managua. Which will consist of 3 stages. A Stage of Sensors and Actuators, Communication Stage and Server Configuration. Which can be monitored from a subdomain of the Firebase platform.

Control of Three-Phase Grid Integrated Multiple Solar Photovoltaic Arrays-BES Based MG

In this article, a three-phase grid integrated multiple solar photovoltaic (PV) arrays-battery energy storage (BES) with a bidirectional converter-based microgrid (MG) system is presented. At dc links of main voltage source converter (VSC) and ancillary VSC, two solar PV arrays are utilized to obtain peak power in cost-effective and proficient single stage configuration through distinct incremental conductance maximum power point (MPP) tracking technique. The individual nonlinear loads are linked in parallel at terminals of VSCs, at the point of common coupling (PCC) and, which facilitate the MG expansion to transfer active power to the grid, and to enhance the reliability of MG in off-grid mode. The main VSC operates through the current control, in the grid interactive mode and during fault in the grid, its shifts transient free to the voltage control in an off-grid mode. At PCC, the voltage control, maintains the frequency and voltage, therefore, the ancillary VSC works with current control. A buck–boost converter is interlinks by BES across the main VSC, which regulates the load levelling and maintains voltage for MPPT at its dc link. In order to improve the dynamic performance of system, a feed-forward constituent of PV array power is utilized in the current control algorithm of VSCs, which also enhances the power quality issues. The MG's performance is found satisfactory for scenarios like, load variation, solar insolation change, load unbalance and during inaccessibility of solar power and the grid. The MG is modeled using MATLAB/ SIMULINK and validated in RT-LAB platform of a real time controller OPAL-RT (OP4510).

A Single-Stage Three Phase CT-Type MLI for Grid Integration and for Supplying Critical Loads

Power system reliability and resiliency involves availability of uninterrupted power supply to loads. With ever-increasing natural and man-made disturbances in power grid, the need of alternate renewable based source of supply is gaining more attention. This paper presents an efficient renewable energy-based single stage configuration for standalone application to provide uninterrupted power supply to critical loads in case of grid power interruption. This configuration can also be used for grid integration during peak load demand of power. The advancement in research of Multilevel Inverter (MLI) relating to high voltage with high power energy control enabled increased use of MLI in renewable energy, especially PV and fuel cell-based systems. The renewable energy-based configuration proposed in this paper uses Cross T-Type (CT-Type) MLI which provides quality output power from solar PV, fuel cell etc. Moreover, the absence of any DC-DC converter reduces complexity and makes the system more economical for grid integration. The overall system performance improves compared to existing methods in terms of total harmonic distortion (THD), total standing voltage (TSV), number of levels, number of components requirement and efficiency.

Effect of multi-staging in vacuum membrane distillation on productivity and temperature polarization

MSVMD (multi-stage vacuum membrane distillation) has recently gained attention as means of enhancing the performance of single stage configuration. The present study is aimed to analyze the impact of multi-staging in VMD (vacuum membrane distillation) on productivity and the associated temperature polarization. Another goal is to determine the point of inversion, a point after which further multi-staging is no more beneficial both in terms of permeate productivity (flux) and associated temperature polarization. After validation with the experimental data, a parametric analysis of MSVMD performance is carried out numerically. Further, the permeate productivity and associated temperature polarization phenomenon were analyzed simultaneously under varying membrane specifications. The optimum number of stages, giving the maximum possible performance of MSVMD, is estimated for variation in most prominent process variables and membrane specifications. The point of inversion was found to be above 40 stages for varying process variables, however, it remained well below 20 stages for variation in some of the prominent membrane characteristics.

A Novel Fundamental Frequency Switching Operation for Conventional VSI to Enable Single-Stage High-Gain Boost Inversion with ANN Tuned QWS Controller

Single-stage high-gain inverters have recently gained much research focus as interfaces for inherent low voltage DC sources such as fuel cells, storage batteries, and solar panels. Many impedance-assisted inverters with different input stage configurations have been presented. To decrease passive component sizes, these inverters operate at high-frequency switching. The high-frequency switching optimizes the passive component sizes but introduces many challenges in the form of high-frequency inductor design, control complexity, high-frequency gate driver requirements, high semiconductor losses, and electromagnetic interferences. This article proposes a novel fundamental frequency switching operation for the conventional voltage source inverters (VSI) to operate as a single-stage high-gain inverter. As the novel operational strategy changes the behavior of conventional VSI from buck inverter to a boost inverter, it is hereafter termed as a novel inverter. By virtue of the operation strategy, switches withstand peak inverse voltage (PIV) equal to DC link voltage, unlike other impedance assisted boost inverters where PIV across switches is the amplified DC voltage. The proposed inverter can invert low-level DC voltage to high voltage AC with low total harmonic distortion (THD) in a single stage without the help of any external filter. A novel quarter-wave symmetric phase-shift controller is proposed for variable voltage and frequency control of proposed inverters tuned by a back-propagation thin-plate-spline neural network (BPTPSNN). Mathematical analysis with experimental validation is presented. Experimentation is carried out on a prototype of 2 kW for single-phase resistive load, induction motor, and non-linear loads.

Design Concept and Structural Configuration of Magnetic Levitation Stage with Z-Assist System

Magnetic levitation technology is expected to provide a solution for achieving nanometer-scale positioning accuracy. However, magnetic leakage limits the application of the magnetic levitation stage. To reduce magnetic density, motors should be installed at an appropriate distance from the table. This increases the axis interference between the horizontal thrust and the pitching, making it difficult to achieve stable levitation. In this study, a magnetic levitation stage system that has a unique motor structure fusing a gravity compensation function and pitching moment compensation is proposed. This compensation mechanism operates automatically using the passive magnetic circuit structure, ensuring that noises from the coil current and the timing gaps do not affect the driving characteristics and that neither wiring nor sensors are required. The basic characteristics were evaluated through the driving experiments, and the efficiency of the proposed gravity and pitching moment compensation system was demonstrated.

Renewable Source Automatic Switching System Apprised on IOT

Now a days non pollution power production is popular because of less pollution and eco-friendly. This paper presents a new system configuration of the front-end rectifier stage for automatic energy management system of renewable energy source. In today’s technology driven world electricity is one of the foremost things for our day-to-day life activities. As we all are oblivious of the fact that the renewable sources of energy are depleting at a lightning-fast rate. So, it’s time for us to shift the focus from conventional to non-conventional sources of energy to produce electricity. The output of the electricity produced by non-conventional sources is less than their counterparts. Renewable sources do not have any detrimental effect on the environment. Solar- wind and main automatic energy management system of renewable energy is basically an integration of solar plant and a wind energy plant. It will help in providing the uninterrupted power supply. As during bad weather conditions, the production can be shifted from one source to other with the help of a microcontroller. A microcontroller ensures the optimum utilization of resources and it also increases the efficiency of the combined system as compared to the individual mode of generation. It helps in decreasing the dependence on one single source and makes the system more reliable. The system can be used for both industrial and domestic applications. This configuration allows the two or more sources to supply the load depending on the availability of the energy sources and priority.

Probiotic Yeasts and Vibrio anguillarum Infection Modify the Microbiome of Zebrafish Larvae

The host microbiome plays an essential role in health and disease. Microbiome modification by pathogens or probiotics has been poorly explored especially in the case of probiotic yeasts. Next-generation sequencing currently provides the best tools for their characterization. Debaryomyces hansenii 97 (D. hansenii 97) and Yarrowia lipolytica 242 (Y. lipolytica 242) are yeasts that protect wildtype zebrafish (Danio rerio) larvae against a Vibrio anguillarum (V. anguillarum) infection, increasing their survival rate. We investigate the effect of these microorganisms on the microbiome and neutrophil response (inflammation) in zebrafish larvae line Tg(Bacmpx:GFP)i114. We postulated that preinoculation of larvae with yeasts would attenuate the intestinal neutrophil response and prevent modification of the larval microbiome induced by the pathogen. Microbiome study was performed by sequencing the V3-V4 region of the 16S rRNA gene and prediction of metabolic pathways by Piphillin in conventionally raised larvae. Survival and the neutrophil response were both evaluated in conventional and germ-free conditions. V. anguillarum infection resulted in higher neutrophil number in the intestinal area compared to non-infected larvae in both conditions. In germ-free conditions, infected larvae pre-inoculated with yeasts showed fewer neutrophil numbers than infected larvae. In both conditions, only D. hansenii 97 increased the survival of infected larvae. Beta diversity of the microbiota was modified by V. anguillarum and both yeasts, compared to non-inoculated larvae. At 3 days post-infection, V. anguillarum modified the relative abundance of 10 genera, and pre-inoculation with D. hansenii 97 and Y. lipolytica 242 prevented the modification of 5 and 6 of these genera, respectively. Both yeasts prevent the increase of Ensifer and Vogesella identified as negative predictors for larval survival (accounting for 40 and 27 of the variance, respectively). In addition, yeast pre-inoculation prevents changes in some metabolic pathways altered by V. anguillarum’s infection. These results suggest that both yeasts and V. anguillarum can shape the larval microbiota configuration in the early developmental stage of D. rerio. Moreover, modulation of key taxa or metabolic pathways of the larval microbiome by yeasts can be associated with the survival of infected larvae. This study contributes to the understanding of yeast–pathogen–microbiome interactions, although further studies are needed to elucidate the mechanisms involved.

Optimization of Translational Flexure Joints Using Corrugated Units Under Stress Constraints

Abstract When optimizing corrugated flexure (CF) joints, most approaches for calculating the maximum stress on the CF beam depend on finite element analysis (FEA). The current paper introduces the design optimization for joints using CF units under stress constraints. The stress state is solved; based on that, the maximum displacement under stress constraints is deduced. The natural frequency formula of the translational joint is further derived from the results of the stiffness matrix. The stage configurations corresponding to the maximum displacement are optimized by restricting the off-axis/axial stiffness ratio and natural frequency of the joint. The optimal results of different types are validated by FEA and experiments.

Origin and evolution of unconformities in a continental rift basin: a case study from the Lishu Depression in Songliao Basin, China

A variety of unconformity types are commonly developed during the rifting of a continental basin. Identifying their origin and evolution is a prerequisite to understanding the complex tectono-sedimentary evolution of the basin and to evaluate the basin’s oil and gas resources. Based on the 2D/3D seismic, geophysical logging, and subsurface lithological data, the unconformities within the rift layer of the Lishu Depression in the Songliao Basin are identified as disconformities, nonconformities, and four “types” of angular unconformities. Their evolution and origin are analyzed by associating the unconformities with the basin’s tectonic evolution. The results show that the rifting of the Lishu Depression was not a continuous process. Instead, several regional tectonic episodes influenced the basin’s evolution. Episodic compressional events and a phase of extension along the main faults determined the basin configuration and sedimentary fill characteristics of different sub-rifting stages. The tectonic history and related paleogeomorphology changes are the dominant factors in the formation of these different unconformity types. During the rifting process, the type and distribution of unconformity varied. In the initial rifting stage, the basin developed a nonconformity and four types of angular unconformities as the result of both regional uplift and fault block tilt. Rotation and tilting of the fault blocks during the intensive rifting resulted in two types of angular unconformities. Finally, in the recession rifting stage, a different form of angular unconformity and disconformity developed, mainly as a result of the regional uplift and subsequent subsidence.

Optimizing multistage reverse electrodialysis for enhanced energy recovery from river water and seawater: Experimental and modeling investigation

• Fair comparison between single-stage and multistage reverse electrodialysis. • New “saving the gradient” electrical control strategy improves process performance. • To harvest energy from river water and seawater, applying two stages is optimal. • Reducing stack pressure drops favors multistage application. Reverse electrodialysis has been established as a promising method to harvest salinity gradient energy. To achieve market viability, an optimum process configuration is needed, in addition to material and stack development, to increase energy efficiency without compromising power density. Multistage reverse electrodialysis is a practical strategy providing several degrees of freedom, such as independent electrical control of the stages, asymmetric staging, and different configurations. This study tests a two-stage configuration experimentally, using seawater and river water (NaCl only), at several residence times and changing the electrical control. Furthermore, the results are compared with a numerical model that is subsequently used to predict the behavior of alternative multistage configurations. The results show that multistage reverse electrodialysis yields higher gross power density and energy efficiency than a single-stage configuration fed with the same salinity gradient. A new strategy named “saving the gradient” (i.e., lowering the discharge current in the first stage) increased the gross overall performance of the two stages up to 17% relative to single-stage and up to 6% relative to a sequentially optimized two-stage system. Modeling different configurations revealed that only two stages are needed when feeding seawater and river water. When retrieving 40% net energy efficiency, the net power density for a single stage is 0.86 W∙m −2 and 0.94 W∙m −2 for a two-stage system, representing an improvement of 9%. Multistage reverse electrodialysis is therefore a viable concept to enhance power and energy efficiency, and benefits from optimization through electrical control.