Integration Operation Research Articles

Use of Heat Pumps in the Hydrogen Production Cycle at Thermal Power Plants

The paper considers the integration and joint operation of a methane steam reforming unit (MSRU) and a heat pump unit (HPU) at a thermal power plant (TPP) as one of the possible ways to follow the global decarbonization policy. Research methods are simulation modeling of a thermal power plant in the program “United Cycle” and analysis of thermodynamic cycles of heat pumps. The Petrozavodskaya combined heat and power plant (CHPP) was selected as the object of the research. During the research, technological schemes for hydrogen production at the Petrozavodskaya CHPP were developed: with steam extraction to MSRU from a live steam collector and with the use of production steam. A scheme for HPU integration is proposed to reduce the cost of hydrogen and to reduce waste heat. A heat pump is used to preheat natural gas before going to MSRU. A method for determining fuel costs for hydrogen production in the trigeneration cycle of a thermal power plant was developed. The minimum specific fuel consumption for hydrogen production—7.854 t ref.f./t H2—is achieved in the mode with steam extraction to MSRU from the turbine PT-60-130/13 (industrial extraction with a flow rate of 30 t/h). At this mode, the coefficient of fuel heat utilization is the highest among all modes with hydrogen production—66.18%.

Design of sampling-based noniterative algorithms for centroid type-reduction of general type-2 fuzzy logic systems

General type-2 (GT2) fuzzy logic systems (FLSs) become a popular research topic for the past few years. Usually the Karnik–Mendel algorithms are the most prevalent approach to complete the type-reduction. Nonetheless, the iterative quality of these types of computational intensive algorithms might impede applying them. For the improved types of algorithms, some noniterative algorithms can enhance the calculation efficiencies greatly, while it is still an open problem for comparing the relation between the discrete TR algorithms and corresponding continuous TR algorithms. First, the sum and integral operations in discrete and continuous noniterative algorithms are compared. Then, three kinds of noniterative algorithms originate from the type-reduction of interval type-2 FLSs are extended to complete the centroid type-reduction of general T2 FLSs. Four computer simulations prove that while changing the number of samples suitably, the calculational results of discrete types of algorithms may accurately gain on the related continuous types of algorithms, and the calculational times of discrete types of algorithms are obviously less than the continuous types of algorithms, this may offer the possible meaning for designing and applying T2 FLSs.

Real-Time Multi-Modal Human–Robot Collaboration Using Gestures and Speech

Abstract As artificial intelligence and industrial automation are developing, human–robot collaboration (HRC) with advanced interaction capabilities has become an increasingly significant area of research. In this paper, we design and develop a real-time, multi-model HRC system using speech and gestures. A set of 16 dynamic gestures is designed for communication from a human to an industrial robot. A data set of dynamic gestures is designed and constructed, and it will be shared with the community. A convolutional neural network is developed to recognize the dynamic gestures in real time using the motion history image and deep learning methods. An improved open-source speech recognizer is used for real-time speech recognition of the human worker. An integration strategy is proposed to integrate the gesture and speech recognition results, and a software interface is designed for system visualization. A multi-threading architecture is constructed for simultaneously operating multiple tasks, including gesture and speech data collection and recognition, data integration, robot control, and software interface operation. The various methods and algorithms are integrated to develop the HRC system, with a platform constructed to demonstrate the system performance. The experimental results validate the feasibility and effectiveness of the proposed algorithms and the HRC system.

A Novel 5G-advanced Core Network Intelligent Operation and Maintenance System

The 5G core network adopts Network Functions Virtualization technology, which forms a variety of virtual resources for general computing, storage, and network hardware to achieve dynamic and flexible deployment of network functions and resources based on needs. With large-scale commercial deployment of cloud-native 5G core network with network function virtualization technology, the operation and maintenance of 5G core network is facing new challenges. This paper describes the architecture and deployment characteristics of 5G core network, and analyses the challenges brought to operation and maintenance by new network characteristics such as SBA, NFV, MEC and separated UPF, as well as the difficulties of operation and maintenance of virtual deployed 5G core network. Combined with the architecture evolution and function enhancement of 5G-Advanced, the architecture and scheme of A Novel Intelligent 5G-Advanced Core Network Operation and Maintenance System are proposed. The architecture and scheme of 5G core network operation and maintenance system construction were proposed, and suggestions on the organizational structure of 5G core network cloud-network integration operation and maintenance were put forward, so as to provide reference for 5G core network cloud-network integration operation and maintenance. The proposed scheme improves the performance of operation and maintenance of 5G core network significantly.

Electrochemical Exfoliation of Naturally Occurring Layered Mineral Stibnite (Sb2S3) for Highly Sensitive and Fast Room‐Temperature Acetone Sensing

AbstractThe analysis of exhaled acetone is used as a noninvasive diagnosis for diabetes. Compared with traditional breath analysis tools, chemiresistive gas sensors have attracted more attention for real‐time monitoring, owing to the possibility of integration and facile operation. However, most reported room‐temperature acetone gas sensors suffer from complicated preparation, costly raw materials, or relatively long response and recovery time. In this work, naturally occurring layered mineral stibnite is used to prepare Sb2S3 by a one‐step method of electrochemical cathodic exfoliation. As‐prepared Sb2S3 displays an amorphous feature with porous, hierarchical nanostructure, and its formation mechanism is rationally proposed. The porous, hierarchical and amorphous Sb2S3‐based gas sensors show excellent gas sensing performance toward acetone at room temperature, with the high response up to 1.46 toward 100 ppm acetone, and fast gas response and recovery toward acetone at room temperature (7 s for response and 30 s for one response–recovery cycle), which is one of the top three shortest response times among the reported room‐temperature acetone gas sensors. The electrochemical cathodic exfoliation may offer a new strategy for facile preparation of mineral materials, and the discussed devices may hold great promise for developing cost‐effective and high‐performance acetone sensors at room temperature.

A Dual-Frequency Terahertz Metasurface Capable of Distinguishing the Handedness of Circularly Polarized Light

Circularly polarized light can present more optical properties of chiral materials and is widely used to analyze and detect biomolecules. In this paper, a dual-frequency terahertz circular polarization detection structure, which is based on multilayer metamaterials, is proposed. The proposed structure consists of a dual-frequency quarter-wave plate, a polyimide spacer, and a filter. The simulation results show that the structure can distinguish the handedness of circularly polarized light by filtering. The extinction ratios are 4 dB and 5.26 dB at 0.952 THz and 1.03 THz, respectively, and the maximum transmittance efficiency reaches 40%. Given the advantages of easy integration and dual-frequency operation, our design is bound to facilitate the development of multi-frequency detection in biomedical imaging devices.

Multiple refinement and integration network for Salient Object Detection

The purpose of the salient object detection (SOD) task is to suppress the background noise and segment the salient foreground regions. Some previous methods considered the strategies of background suppression and multi-level feature fusion. Other methods encountered the problem that single-scale convolution features are difficult to capture the correct object size. This paper reconsiders the above problems and proposes a comprehensive solution to achieve SOD for improving the detection performance and ensuring relatively fewer parameters. First, it is difficult to achieve a better refinement effect through only one refinement operation. To this end, a multi-scale denoising module (MSDM) and multi-pooling refinement module (MPRM) are proposed to jointly complete the refinement task of multi-level features. Besides, it is difficult to fully integrate complementary features through only one feature integration operation. Mutual learning module (MLM) is proposed to preliminarily integrate multi-level features. To reduce information redundancy, multi-attention (MA) mechanism is used to assist further integration. The proposed algorithm is called multiple refinement and integration network (MRINet). Experimental results on five benchmark datasets show that MRINet outperforms state-of-the-art methods on multiple evaluation metrics. Moreover, our ResNet-based algorithm only contains 25.202 million parameters, which is less than other ResNet-based algorithms and can run at over 37 fps on a single GPU. The code will be available at https://github.com/dc3234/MRINet.

Fast calculation of orbital angular momentum flux density of partially coherent Schell-model beams on propagation.

Optical coherence has recently become a degree of freedom to modulate the orbital angular momentum (OAM) flux density of a partially coherent beam during propagation. However, the calculation of the OAM flux density for the partially coherent beam involves partial differential and four-dimensional integral operations, which poses drawbacks for its fast numerical calculations. In this paper, we present an efficient numerical protocol for calculating the OAM flux density of any partially coherent Schell-model beam propagating through a paraxial ABCD optical system by only adopting two-dimensional (2D) Fourier transforms. The general formalism is established in detail for the fast numerical calculation of the OAM flux density. It is found that the operation number in the developed algorithm is independent on the spatial coherence states of the beam. To demonstrate the validity of our algorithm, we calculate the OAM flux density of the partially coherent Laguerre-Gaussian beams during propagation with both the analytical and numerical methods. The obtained results are consistent well with each other. Moreover, the OAM flux density properties of two other classes of Schell-model beams, having no analytical solutions, are investigated as the specific examples. Our method provides a convenient way for studying the correlation-induced OAM density changes for any Schell-model beam propagation through a paraxial optical system.

Atomically-thin Schottky-like photo-electrocatalytic cross-flow membrane reactors for ultrafast remediation of persistent organic pollutants

The remediation of persistent organic pollutants in surface and ground water represents a major environmental challenge worldwide. Conventional physico-chemical techniques do not efficiently remove such persistent organic pollutants and new remediation techniques are therefore required. Photo-electro catalytic membranes represent an emerging solution that can combine photocatalytic and electrocatalytic degradation of contaminants along with molecular sieving. Herein, macro-porous photo-electro catalytic membranes were prepared using conductive and porous stainless steel metal membranes decorated with nano coatings of semiconductor photocatalytic metal oxides (TiO2 and ZnO) via atomic layer deposition, producing highly conformal and stable coatings. The metal - semiconductor junction between the stainless steel membranes and photocatalysts provides Schottky - like characteristics to the coated membranes. The PEC membranes showed induced hydrophilicity from the nano-coatings and enhanced electro-chemical properties due to the Schottky junction. A high electron transfer rate was also induced in the coated membranes as the photocurrent efficiency increased by 4 times. The photo-electrocatalytic efficiency of the TiO2 and ZnO coated membranes were demonstrated in batch and cross flow filtration reactors for the degradation of persistent organic pollutant solution, offering increased degradation kinetic factors by 2.9 and 2.3 compared to photocatalysis and electrocatalysis, respectively. The recombination of photo-induced electron and hole pairs is mitigated during the photo-electrocatalytic process, resulting in an enhanced catalytic performance. The strategy offers outstanding perspectives to design stimuli-responsive membrane materials able to sieve and degrade simultaneously toxic contaminants towards greater process integration and self-cleaning operations.

A Novel Optimization Model of Integrated Energy System considering Thermal Inertia and Gas Inertia

Aiming at the energy multivariate heterogeneity of thermal system and natural gas system, a novel optimization model of integrated energy system considering thermal inertia and gas inertia is proposed. First, the dynamic characteristics of the thermal system in the integrated energy system are studied, and the inertia model of the heat network pipeline and thermal building is established. Second, the characteristics of natural gas pipeline network storage are studied, and the natural gas storage and pressure energy generation models are established. Then, the optimization objective of the minimum integrated operating cost of the integrated energy system is established, and the YALMIP solver is used to solve it. Finally, a numerical example is introduced to analyze the operating cost of the integrated energy system in different scenarios, and it is verified that the integrated energy system optimization model considering the inertia of the thermal and gas proposed in this paper can effectively improve the system regulation capability and reduce the system operating cost.

A Novel Method for Tunnel Digital Twin Construction and Virtual-Real Fusion Application

Tunnels play important roles in integrated transport infrastructure. A digital twin reproduces a real tunnel scene in virtual space and provides new means for tunnel digital maintenance. Aiming at the existing problems of video fragmentation, separation of video and business data, and lack of two- and three-dimensional linkage response methods in tunnel digital operation, in this paper, we propose a novel method for tunnel digital twin construction and virtual-real integration operation. Firstly, the digital management requirements of tunnel operations are systematically analyzed to clarify the purpose of digital twin construction. Secondly, BIM technology is used to construct a static model of the tunnel scene that conforms to the real tunnel main structure. Thirdly, a three-dimensional registration and projection calculation method is proposed to integrate tunnel surveillance video into a three-dimensional virtual scene in real time. Fourthly, multi-source sensing data are gathered and fused to form a digital twin scene that is basically the same as the real tunnel traffic operations scene. Finally, a management model suitable for digital twins is discussed to improve the efficiency of tunnel operations and management, and a tunnel in China is selected to verify this method. The results show that the proposed method is helpful to realize the application of two- and three-dimensional linkages of tunnel traffic smooth, accident rescue, facility management, and emergency response, and to improve the efficiency of tunnel digital management.

Analysis and simulation of BECCS vertical integration model in China based on evolutionary game and system dynamics

Bioenergy with carbon capture and storage (BECCS) is a key negative emission technology in response to climate change. The industrial chain of BECCS is composed of multi-agent participants: farmers, middlemen, enterprises. This paper fills a gap in BECCS research by establishing a tripartite evolutionary game model and conducting system dynamics simulation to analyze the participants’ interaction and strategy choices on system equilibrium in supply chain of BECCS under vertical integration operation model, and further discussing the influence of policy incentives on BECCS. The results show that the willingness of both enterprises and middlemen participate in the cooperation is very low under current scenario. Therefore, appropriate incentives must be taken to promote commercial deployment of BECCS. From sensitivity analysis, the following useful references for practical applications of BECCS in the future are obtained: Compared with other factors, costs of carbon storage have a more significant impact on the evolutionary trajectories and are highly sensitive to evolutionary equilibrium. The government should subsidize carbon utilization and electricity tariffs, but could not provide an initial investment subsidy for BECCS retrofit. Vigorously developing middlemen and promoting the improvement of carbon trading market and carbon tax policies are also of great significance to implementation of BECCS.

Two-Dimensional Field-Effect Transistor Sensors: The Road toward Commercialization.

The evolutionary success in information technology has been sustained by the rapid growth of sensor technology. Recently, advances in sensor technology have promoted the ambitious requirement to build intelligent systems that can be controlled by external stimuli along with independent operation, adaptivity, and low energy expenditure. Among various sensing techniques, field-effect transistors (FETs) with channels made of two-dimensional (2D) materials attract increasing attention for advantages such as label-free detection, fast response, easy operation, and capability of integration. With atomic thickness, 2D materials restrict the carrier flow within the material surface and expose it directly to the external environment, leading to efficient signal acquisition and conversion. This review summarizes the latest advances of 2D-materials-based FET (2D FET) sensors in a comprehensive manner that contains the material, operating principles, fabrication technologies, proof-of-concept applications, and prototypes. First, a brief description of the background and fundamentals is provided. The subsequent contents summarize physical, chemical, and biological 2D FET sensors and their applications. Then, we highlight the challenges of their commercialization and discuss corresponding solution techniques. The following section presents a systematic survey of recent progress in developing commercial prototypes. Lastly, we summarize the long-standing efforts and prospective future development of 2D FET-based sensing systems toward commercialization.

Optimized economic operation of energy storage integration using improved gravitational search algorithm and dual stage optimization

This paper presents optimized energy storage and distribution network model under uncertainty of the power generation problem, based on an improved gravitational search algorithm (IGSA). Throughout the search phase, the IGSA uses a trial-and-error strategy to update the best agent. It also modifies the orbit of the poor agent in the late stages of the search and uses the coordinate descent approach to search for the optimal agent's position. A dual-stage optimization (DSO) model is employed for energy storage and uncertainty of energy generation. The hybrid IGSA-DSO used an adoptive speed inertia coefficient which ensures global and local searchability. The features of the proposed model were validated using IEEE-RTS 24 bus test system with various cases to realize the coordinated planning of the power grid and energy storage. Finally, the simulation shows interesting results of the proposed approach (IGSA-DSO), which reduces the investment cost by 0.248% comparatively.

Topology-Based Accurate Modeling of Current-Mode Voltage Regulator Modules for Power Distribution Network Design

Power distribution network (PDN) is essential in electronic systems to provide reliable power for load devices. Thus, modeling of PDNs in printed circuit boards and packages has been extensively studied in the past few decades. However, with the higher integration levels and operation bandwidths of modern voltage regulator module (VRM), there lacks an accurate model for transient load responses based on the widely used current-mode control topology. In this work, a topology-based behavior model, including both the power stage and control loops, is developed for the current-mode buck VRM. A novel method is also proposed to unify the modeling of the continuous and discontinuous conduction modes for transient load responses. Through the measurement-based characterization, the model parameters are optimized to match with the actual design. Furthermore, this model can be applied to both the time-domain and frequency-domain circuit simulations to predict the voltage droop and output impedance, respectively. The accuracy of the model is validated using an evaluation board containing the single-phase and multiphase VRMs. The proposed model for current-mode control VRM can be easily cascaded with other PDN components to enable a combined PDN analysis.

A novel sliding mode observer-based compound sliding mode current control with active damping for single phase grid-tied inverter system in weak grid

This paper proposes a novel sliding mode observer (SMO)-based compound sliding mode current control (CSMCC) strategy with active damping for the single-phase grid-tied inverter system in weak grid. To decrease the number of measurement sensors and thus reduce system cost, the SMO with rapid response and low chattering level is designed for estimating the inverter-side current and capacitor voltage of LCL-type filter, which is used for feedback control. To enhance robustness against the parameter variation of grid-tied inverter system, the CSMCC is put forward, which is composed of two parts. One part is the equivalent control for grid-tied inverter system with nominal parameters, and the other part is the reaching law-based second-order nonsingular terminal sliding mode control (NTSMC) for compensating the disturbance due to the parameter variations. Since an adaptive gain of switching function is employed and there is integral operation for this discontinuous switching function, the proposed NTSMC strategy not only speed up system response but also attenuate the system chattering level significantly. Moreover, for inhibition of inherent resonance resulting from LCL-type filter, the weighted average current-based active damping is used to provide feedback current for CSMCC. Comprehensive simulation and experimental results show that the proposed strategy can enable the grid-tied inverter system to not only have strong robustness against the filter parameters & grid impedance variations but also improve the quality of grid current, and have satisfactory suppression effect of background grid voltage harmonics on grid current.

Contramodules

Contramodules are module-like algebraic structures endowed with infinite summation (or, occasionally, integration) operations satisfying natural axioms. Introduced originally by Eilenberg and Moore in 1965 in the case of coalgebras over commutative rings, contramodules experience a small renaissance now after being all but forgotten for three decades between 1970-2000. Here we present a review of various definitions and results related to contramodules (drawing mostly from our monographs and preprints arXiv:0708.3398, arXiv:0905.2621, arXiv:1202.2697, arXiv:1209.2995, arXiv:1512.08119, arXiv:1710.02230, arXiv:1705.04960, arXiv:1808.00937) - including contramodules over corings, topological associative rings, topological Lie algebras and topological groups, semicontramodules over semialgebras, and a "contra version" of the Bernstein-Gelfand-Gelfand category O. Several underived manifestations of the comodule-contramodule correspondence phenomenon are discussed.

Derivative Probes Signal Integration Techniques for High Energy Pulses Measurements

The paper presents problems related to the processing of signals recorded with differential field probes E and H. The fundamental problem to which special attention has been paid is the result of the integration operation. Due to the presence of constant/slowly-varying components in the raw signal, there is a drift present in the outcome of integration. This line wander can be enormous. This is particularly evident if the integration is performed in a standard manner, uniformly over the entire recorded waveform. The paper contains the Authors’ proposition to segment the signal and perform the integration independently in each of the sub-regions. This approach is based on the assumption of a local mean value instead of its global character for the recorded waveform. Although this leads to more complex signal processing, it gives significantly better results as it is suppressing the deterioration drift in the integrated signal more than 400 times. The results are presented on laboratory recordings and outdoor tests. In the first case, voltage pulses with durations of about 50 ns and rise times in the range of single ns were recorded. In the second case, high-energy electromagnetic pulse signals were used. It was formed by sinusoidal waveforms packets of 3 GHz frequency with a single packet duration of 5 μs and packet repetition frequency f ≤ 300 Hz.

Multi-Mission Thermoelectric Generator Fueling Testing and Integration Operations for Mars 2020

The Space Nuclear Power and Isotope Technologies (SNPIT) Division at Idaho National Laboratory fuels, performs acceptance testing, and provides spacecraft integration support of radioisotope power systems in support of National Aeronautics and Space Administration missions. Recently, the SNPIT team completed fueling, testing, and launch support of the Multi-Mission Radioisotope Thermoelectric Generator for the Mars 2020 Perseverance Rover mission.

Study on instability discriminating condition and permeability variation of triangle articulated structure in highly inclined goaf

The huge, inclined goaf formed by the mining of steeply inclined and extra thick coal seams has the characteristics of occupying a large space and being subject to complex breaking behavior of its overlying rock structure, especially the rock block structure characteristics of the interface area between the goaf and the lower working face which is difficult to be characterized, leading to a hidden danger when mining the lower working face. In response to the aforementioned problems, the following conclusions are drawing as follows: (1) with the aid of the contradiction method, the critical condition governing instability of the triangular articulated structure was obtained to explain the correctness of the assumption of the triangular hinged structure; (2) three-point truss structure was composed of key layer blocks; (3) in the stabilization stage of the triangular hinged structure, the fracture network area was extracted, and the centerline intensive equivalent method of a single fracture segment was adopted to directly measure the equivalent length. Meanwhile, the value of equivalent average width with the equivalent length of a single crack was calculated by integral operation and equivalent figure calculation; (4) the mathematical expressions of permeability which was positively exponential function related to the ratio of equivalent average width to equivalent length were derived. Furthermore, the vectorized solution of seepage rate was carried out respectively for the goaf area and the extracted network area by using COMSOL software. The distribution of the strong seepage area of CBM and the ratio of equivalent average width to equivalent length is found to be consistent to a large extent, which provides theoretical support for subsequent CBM management.