Records with Subject: Process Control
Showing records 1 to 25 of 3416. [First] Page: 1 2 3 4 5 Last
Adomian Decomposition, Firing Change Process Analysis and Synchronous Control of Fractional-Order Hindmarsh−Rose Neurons in Electromagnetic Field
Tengfei Lei, Haiyan Fu, Hongyan Zang, Lili Huang, Wenqiang Sun
November 30, 2023 (v1)
Keywords: firing, fractional-order HR neurons, ISI bifurcation diagram, synchronous control
In this paper, based on integer-order Hindmarsh−Rose (HR) neurons under an electric field, the fractional-order model is constructed, and the nonlinear term is decomposed by the Adomian decomposition method, and the numerical solution of the system is obtained. The firing behavior of the neuron model is analyzed by using a phase diagram, interspike interval (ISI) bifurcation diagram, sample entropy (SE) complexity, and largest Lyapunov exponent (LLE). Based on the sliding mode control theory, a chaos synchronization controller of the system is designed. Matlab simulation results show that the controller is realizable and effective, and also has the characteristic of fast response, which provides a reference for the control and application of a memristor neural network system.
Investigating the Mechanism of Continuous−Discrete Coupled Destabilization of Roadway-Surrounding Rocks in Weakly Cemented Strata under Varying Levels of Moisture Content
Lihui Sun, Zhixin Jiang, Yaxin Long, Qingfeng He, Haiyang Zhang
November 30, 2023 (v1)
Keywords: anchorage failure mechanism, continuous–discrete, destabilization mechanism, moisture content, weakly cemented rock
This study examines frequent disasters, including large-scale deformation and collapse, caused by underground mining in weakly cemented strata in Western China. The weakly cemented rock’s unique characteristics, including low strength and easy disintegration, demonstrate a different damage pattern than that traditionally seen in the central and eastern regions. Using Fast Lagrangian Analysis of Continua-Particle Flow Code (FLAC2D-PFC2D) coupling, we model the strata, focusing on the 3-1 coal seam roadway at Hongqinghe mine. This study investigates the damage−rupture−destabilization progression in the peripheral rock under varying levels of moisture content. Our findings indicate that a water content of ω = 5.5% is the threshold for roadway damage, and moisture content 5.5% abruptly increases cracks and shifts the rock’s force chain, causing significant deformation and affecting the ceiling the most. Moreover, higher levels of moisture content weaken the anchor solid’s performance, with... [more]
Discrete-Element-Method-Based Determination of Particle-Level Inputs for the Continuum Theory of Flows with Moderately Cohesive Particles
Kevin M. Kellogg, Peiyuan Liu, Christine M. Hrenya
November 30, 2023 (v1)
Keywords: cohesion, continuum theory, discrete element method, particle flows
In this work, the cohesion-specific inputs for a recent continuum theory for cohesive particles are estimated for moderately cohesive particles that form larger agglomerates via discrete element method (DEM) simulations of an oscillating shear flow. In prior work, these inputs (critical velocities of agglomeration and breakage and collision cylinder diameters) were determined for lightly cohesive particles via the DEM of simple shear flow—i.e., a system dominated by singlets and doublets. Here, the DEM is again used to extract the continuum theory inputs, as experimental measurements are infeasible (i.e., collisions between particles of a diameter of <100 μm). However, simulations of simple shear flow are no longer feasible since the rate of agglomeration grows uncontrollably at higher cohesion levels. Instead, oscillating shear flow DEM simulations are used here to circumvent this issue, allowing for the continuum theory inputs of larger agglomerate sizes to be determined efficient... [more]
Decentralized Control Strategy for Participation of Electric Vehicles in Distribution Voltage Control
Xin Fang, Juan Li, Yubo Yuan, Xiaodong Yuan
November 30, 2023 (v1)
Keywords: decentralized voltage control, electric vehicle, electric vehicle charging station, rolling optimization
With the accelerating transportation electrification, increasing numbers of electric vehicles (EVs) are connected to distribution networks via electric vehicle charging stations (EVCSs). Due to the uncertain charging behaviors of EV users, concentrated high-power EV charging during peak hours can result in significant undervoltage issues, affecting the regular operation of distribution networks and having detrimental effects on regular EV charging. Conventional EV charging scheduling methods are conducted in a centralized way, requiring extensive investment in communication infrastructure and intensive computing power. Accordingly, this paper proposes a novel decentralized voltage control scheme with the participation of EVs and EVCSs. The proposed control scheme first divides the distribution network into clusters based on a modified modularity index. Then, it applies the rolling optimization-based control of the EVs and EVCSs within each cluster to solve the regional voltage problems... [more]
Multi-Sized Granular Suspension Transport Modeling for the Control of Lost Circulation and Formation Damage in Fractured Oil and Gas Reservoirs
Jinhua Liu, Yayun Zhang, Dujie Zhang, Fan Li, Hexiang Zhou, Chengyuan Xu, Weiji Wang
November 30, 2023 (v1)
Keywords: fractured reservoir, gas and geothermal resources, multi-sized granule retention, oil, permeability damage, production enhancement, suspended granule transport
Transport and retention of multi-sized suspended granules are common phenomena in fracture media of oil, gas and geothermal reservoirs. It can lead to severe permeability damage and productivity decline, which has a significant impact on the efficient development of underground resources. However, the granule transport and retention behaviors remain not well understood and quantified. The novel stochastic model is proposed for the multi-sized suspended granule transport in naturally fractured reservoirs accounting for granule retention and fracture clogging kinetics. A percolation fracture network is proposed considering fracture connectivity evolution during suspended granule transport. Granule retention and fracture clogging dynamics equations are proposed to account for incomplete fracture clogging by retained granules. The microscale stochastic model is allowed for upscaling to predict the multi-sized granule transport behavior in naturally fractured reservoirs. The model solution... [more]
An Improved Fault Diagnosis Approach for Pumps Based on Neural Networks with Improved Adaptive Activation Function
Fangfang Zhang, Yebin Li, Dongri Shan, Yuanhong Liu, Fengying Ma
November 30, 2023 (v1)
Keywords: adaptive activation function, deep learning, fault diagnosis, pumping unit
Due to the complex underground environment, pumping machines are prone to producing numerous failures. The indicator diagrams of faults are similar to a certain degree, which produces indistinguishable samples. As the samples increase, manual diagnosis becomes difficult, which decreases the accuracy of fault diagnosis. To accurately and quickly judge the fault type, we propose an improved adaptive activation function and apply it to five types of neural networks. The adaptive activation function improves the negative semi-axis slope of the Rectifying linear unit activation function by combining the gated channel conversion unit to improve the performance of the deep learning model. The proposed adaptive activation function is compared to the traditional activation function through the fault diagnosis data set and the public data set. The results show that the activation function has better nonlinearity and can improve the generalization performance of the deep learning model and the ac... [more]
Review of Recent Advances in the Drive Method of Hydraulic Control Valve
Yanchao Li, Ruichuan Li, Junru Yang, Xiaodong Yu, Jikang Xu
November 30, 2023 (v1)
Keywords: displacement accuracy, drive performance, hydraulic control valve, response speed, spool drive
Hydraulic control valves are widely used in industrial production, agricultural equipment, construction machinery, and other large power equipment for controlling the pressure and flow of fluids in hydraulic systems. The driving method has a significant impact on the response and control accuracy of hydraulic valves. This paper reviews the driving methods of spools from five aspects: solenoid drive, material expansion drive, motor drive, hydraulic valve drive, and another drive. It summarizes the various schemes currently available for spool drive and analyzes each of them. After optimizing the driving method of the valve core, the control accuracy can reach 3%, and the minimum response time is 7 ms. According to the characteristics of the different drive methods, the differences between them are compared, the advantages and disadvantages of each drive method are analyzed, and the application scenarios for each drive method are identified. Solutions to the drawbacks of the existing dri... [more]
Bearing Fault Diagnosis Based on ICEEMDAN Deep Learning Network
Bo Liang, Wuwei Feng
September 21, 2023 (v1)
Keywords: convolutional block attention module, deep learning, deep residual network, Hilbert, ICEEMDAN, rolling bearing fault diagnosis
Bearing fault diagnosis has evolved from machine learning to deep learning, addressing the issues of performance degradation in deep learning networks and the potential loss of key feature information. This paper proposes a fault diagnosis method for rolling bearing faults based on ICEEMDAN combined with the Hilbert transform (ICEEMDAN-Hilbert) and a residual network (ResNet). Firstly, the collected fault vibration signals are classified as fault samples and randomly sampled with a fixed length. The IMF components obtained by decomposing the bearing fault vibration signals using ICEEMDAN are able to maximize the restoration of fault vibrations. Then, the IMF components are transformed from one-dimensional time-domain signals to two-dimensional time-frequency domain images using Hilbert transformation. The RGB color images can be directly used in deep learning models without the need for manual labeling of a large amount of data, thereby avoiding the loss of key feature information. The... [more]
Experimental Study on the Influence of Wind Speed on the Start-Up Characteristics and Thermoelectric Generation Characteristics of Gravity Heat Pipe in Gangue Dump
Bailin Zhang, Shuhua Fang, Songlin Zhang, Runxu Zhang, Yu Zang
September 21, 2023 (v1)
Keywords: gravity heat pipe, start-up characteristic, thermoelectric generation, wind speed
As an efficient heat exchange component, the gravity heat pipe can effectively control the accumulated temperature inside gangue dumps and enable reuse of transferred heat. This study establishes a similar simulation experimental platform for gravity heat pipes to control gangue dumps and thermoelectric generation. The influence of wind speed on the start-up performance and isothermal performance of gravity heat pipes is analyzed, along with the impact of wind speed on their thermoelectric generation performance. Initially, the optimal working fluid height and heating height are determined, followed by a comparison and analysis of the isothermal performance, start-up performance, and thermoelectric generation performance of the gravity heat pipe under different wind speeds. The results indicate that at a wind speed of 1.0 m/s, the gravity heat pipe exhibits better start-up and isothermal performance. At a wind speed of 2.0 m/s, the thermoelectric power generation reaches its peak. In t... [more]
Study on the Reservoir Heterogeneity of Different Volcanic Facies Based on Electrical Imaging Log in the Liaohe Eastern Sag
Zongli Liu, Huanping Wu, Shanyi Zhang, Xiaoqing Zhao
September 21, 2023 (v1)
Keywords: electrical imaging log, heterogeneity, porosity spectrum, volcanic facies
The volcanic rocks of the Es3 Formation (the third member of the Eocene Shahejie) in the Liaohe Eastern Sag can be divided into four facies and twelve subfacies. The porosity spectrum, porosity bin, variation coefficient (VC), and porosity width derived from electrical imaging log data were applied to study and characterize the heterogeneity of four facies and nine subfacies, both qualitatively and quantitatively. However, the VC and porosity width cannot be used to quantitatively classify heterogeneity when the VC is small and the porosity width is large. In the present study, the authors propose a new parameter, Pvcd = variation coefficient × porosity width. Based on this parameter, using a combination of porosity spectra, porosity bin features, VC, and porosity width, lithofacies heterogeneity is divided into three categories. The first is weak heterogeneity, which has a Pvcd < 1.1, a VC < 0.15, and a porosity width < 6. The second is moderate heterogeneity, which has a Pvcd 1... [more]
Evaluation of Foam Gel Compound Profile Control and Flooding Technology in Low-Permeability Reservoirs
Xiaoyu Gu, Gejun Cai, Xuandu Fan, Yanlong He, Feifei Huang, Zhendong Gao, Shaofei Kang
September 21, 2023 (v1)
Keywords: compound profile control and flooding, foam, gel, low permeability reservoir
In the waterflooding development of fractured ultra-low permeability reservoirs, the heterogeneity is becoming increasingly serious. The development of large fracture channels leads to serious water channelling and low recovery, and the effect of conventional profile control is not ideal. This paper proposed gel foam composite profile control and flooding technology to solve the above problems. Herein, the new intelligent gel and foaming agent systems were optimized through laboratory experiments, and their performance was evaluated. The new intelligent gel system has the characteristics of low viscosity, easy preparation, good injection, slow cross-linking, high strength, and long-term effectiveness. The injection parameters were optimized, and the indoor injection scheme was formulated, that is, the optimal injection volumes of gel and foam slugs were 0.3 and 0.6 PV, respectively. The injection sequence of composite slugs was to inject gel slugs first, then foam slugs. The injection... [more]
Experimental Study of Sound Pressure Level in Hydraulic Power Unit with External Gear Pump
Alexander Mitov, Krasimir Nedelchev, Ivan Kralov
September 21, 2023 (v1)
Keywords: experimental study, external gear pump, sound pressure level
The article presents the results of an experimental study of the sound pressure level (SPL) caused by a hydraulic power unit with an external gear pump. The study was carried out with a specially developed laboratory experimental setup based on a common architecture used in hydraulic power units. Both the hydraulic system and the measuring equipment used are described in detail. The design of the experimental studies performed, including two main configurations with specific parameters regarding the operating modes of the system, is presented. The experimental results obtained are presented in the form of magnitude frequency responses which are compared in accordance with the experiment design. An analysis of the results obtained is performed using various quantitative indicators. For specific operating modes, parametric models were derived by approximation of the experimental data. The resulting models can serve in future work to reduce the SPL by passive or active means (e.g., freque... [more]
Research on the Stability of the Spacer Fluid Interface in Dual-Layer Pipe Dual-Gradient Drilling
Guorong Wang, Xiaolei Li, Lin Zhong, Zhiyu Lv
September 21, 2023 (v1)
Keywords: dual-layer pipe dual-gradient drilling, pressure system, spacer fluid interface, stability
Dual-layer pipe dual-gradient drilling technology is an emerging technology for solving the problem of the narrow safety density window in deepwater drilling. The unstable spacer fluid interface in this technology directly affects the dual-gradient pressure system in the annulus, causing changes in the drilling mud performance and affecting the control of bottom hole pressure and rock removal with drilling mud. Therefore, the key to the stable operation of dual-layer pipe dual-gradient drilling technology is to maintain the stability of the spacer fluid interface. Based on this, a seawater-spacer fluid-drilling mud annular flow model was established in this study, with a bottom hole pressure control step of 0.2 MPa, and the spacer fluid height after a single control was used as the evaluation index to study the influence of annular flow velocity, the spacer fluid properties, and the drill string rotation speed on the stability of the spacer fluid interface. The results show that in the... [more]
Low-Power Very-Large-Scale Integration Implementation of Fault-Tolerant Parallel Real Fast Fourier Transform Architectures Using Error Correction Codes and Algorithm-Based Fault-Tolerant Techniques
M. Kalpana Chowdary, Rajasekhar Turaka, Bayan Alabduallah, Mudassir Khan, J. Chinna Babu, Ajmeera Kiran
September 21, 2023 (v1)
Keywords: ABFT, ASIC, FFT, FPGA, soft errors
As technology advances, electronic circuits are more vulnerable to errors. Soft errors are one among them that causes the degradation of a circuit’s reliability. In many applications, protecting critical modules is of main concern. One such module is Fast Fourier Transform (FFT). Real FFT (RFFT) is a memory-based FFT architecture. RFFT architecture can be optimized by its processing element through employing several types of adder and multipliers and an optimized memory usage. It has been seen that various blocks operate simultaneously in many applications. For the protection of parallel FFTs using conventional Error Correction Codes (ECCs), algorithmic-based fault tolerance (ABFT) techniques like Parseval checks and its combination are seen. In this brief, the protection schemes are applied to the single RAM-based parallel RFFTs and dual RAM-based parallel RFFTs. This work is implemented on platforms such as field programmable gate arrays (FPGAs) using Verilog HDL and on application-s... [more]
Dynamic Analysis of a Bolted Joint Rotor-Bearing System with a Blade−Casing Rubbing Fault
Chuanmei Wen, Zhimin Zhu, Xuezhong Fu, Tianliang Long, Bing Li
September 21, 2023 (v1)
Keywords: bending stiffness, blade–casing rubbing fault, bolted joint, dynamic analysis, rotor system
Bolted joints are widely used in aeroengine rotor systems to connect multiple components into an integrated structure and provide sufficient stiffness. The mechanical properties of a bolted joint have a significant effect on rotor dynamics. For modern aeroengine designs, the blade-tip clearance is gradually reduced to improve efficiency, which may lead to rubbing damage and affect safe operation. The mechanical properties of a bolted joint change significantly during the blade−casing rubbing process and influence the dynamic properties of the rotor system. Based on the finite element (FE) modeling method, a 15-node bolted joint rotor system model is established in this paper, in which the bolted joint is represented by a 2-node joint element, and the blade−casing rubbing force is considered. The Newmark method is used to solve the motion equations. The dynamic model is validated by comparing the frequency response characteristics for different numbers of blades with the results provide... [more]
Diagenesis and Diagenetic Mineral Control on Reservoir Quality of Tight Sandstones in the Permian He8 Member, Southern Ningwu Basin
Pengbao Zhang, Shuheng Tang, Donglin Lin, Yanjun Chen, Xiaoxuan Wang, Zhenxing Liu, Feng Han, Peng Lv, Zhoupeng Yang, Xiaoqu Guan, Jiahua Hu, Yan Gao
September 21, 2023 (v1)
Keywords: diagenesis, He8 member, mineral genesis, Ningwu Basin, porosity prediction
The sandstone reservoirs of the He8 member within the Lower Permian Shihezi Formation are important targets for oil and gas exploration in the southern Ningwu Basin. This study utilized thin-section identification, scanning electron microscopy, and X-ray diffraction analysis to examine the petrological features and reservoir characteristics, and evaluate the impact of the mineral composition and diagenesis type on the porosity of the sandstone reservoir. Additionally, a multiple linear regression prediction model was developed to predict the distribution of promising sandstone reservoirs in the study area. The results of the analysis revealed that the sandstone of the He8 member is mainly composed of feldspathic lithic sandstone, followed by lithic sandstone. The main reservoir type is characterized by secondarily dissolved pores and micropores within kaolinite aggregates. The low porosity (ranging from 0.2% to 10.7%) and permeability indicate that the He8 member is a tight sandstone r... [more]
Theoretical Basis and Technical Method of Permeability Enhancement of Tectonic Coal Seam by High Intensity Acoustic Wave In Situ
Weidong Li, Yongmin Zhang, Dalong Wang, Cunqiang Chen, Yongyuan Li, Youzhi Zhao, Shuo Zhang, Jing Ren, Yong Qin
September 21, 2023 (v1)
Keywords: coal seam fissure, coal seam permeability enhancement, controllable shockwave, high-strength acoustic wave, interlayer drilling, structurally controlled coal bed
Tectonic coal seams are characterized by soft, low permeability and high gas outburst. The traditional gas control method is the intensive drilling and extraction in this seam, which is not only large in engineering quantity, high in cost, difficult to form holes and low in extraction efficiency, but also easy to induce coal and gas outburst, which is a difficult problem for global coal mine gas control. To solve this difficult problem, the controllable shockwave equipment developed by the author’s team and successfully applied in the practice of permeability enhancement of coal seam, combined with the principles of shock vibration sound wave generation and shock wave attenuation and evolution in the rock stratum, a new idea of loading a controllable shock wave in the roof and floor of coal seam is proposed. The shock wave first attenuates and evolves into a high-strength sound wave in the roof and floor rock stratum, and then enters and loads into the coal seam to achieve the purpose... [more]
ROV Sliding Mode Controller Design and Simulation
Fushen Ren, Qing Hu
September 21, 2023 (v1)
Keywords: fuzzy control, PID control, ROV, simulate, sliding mode control, Unity3D
Underwater robots play a vital role in the exploration and development of marine resources and the inspection and maintenance of offshore platforms. In this paper, the motion control technology of ROV is studied, the kinematics and dynamics of ROV are analyzed, the kinematics and dynamics models of ROV are established, and the degrees of freedom of the models are decouple according to the control requirements. The fluid damping coefficient of ROV was obtained using Fluent software, and an ROV control system based on sliding mode variable structure was designed. The saturation function was introduced into the sliding mode controller to reduce the adverse effects of buffeting. The classical PID controller, fuzzy PID controller, and sliding mode controller designed in this paper were simulated and analyzed by Simulink. A semi-physical simulation platform based on Unity3D was established. It can be seen from the simulation results and the pool experiment results that the performance of the... [more]
Distributed Fixed-Time Secondary Control for MTDC Systems Using Event-Triggered Communication Scheme
Xiaoyue Zhang, Xinghua Liu, Peng Wang
September 20, 2023 (v1)
Keywords: distributed fixed-time control, event-triggered communication scheme, MTDC system
Multi-terminal DC transmission (MTDC) systems have attracted much attention due to their significant advantages in long-distance and high-capacity transmission. To improve their reliability and operation performance, a distributed fixed-time secondary control of frequency restoration and active power sharing is proposed under event-triggered communication, which only depends on the states of each AC grid and its neighbors. By utilizing Lyapunov theory, we prove that the MTDC system with the fixed-time secondary control can be stable in a settling time, and the conditions of the settling time are established for fixed-time algorithms. In addition, we simulate a five-terminal MTDC system in Matlab/Simulink. Several cases of MTDC systems are exhibited to showcase how well the suggested controller works when dealing with load changes and attacks. The comparison of the number of event-triggered instants shows that the proposed control method can effectively reduce communication resources.
Identifying the Saturated Line Based on the Number of Idle Places: Achieving Precise Maximal Permissiveness without Deadlocks Using Control Transitions or Control Places
Ter-Chan Row, Shih-Chih Lee, Yen-Liang Pan
September 20, 2023 (v1)
Keywords: deadlock prevention, deadlock recovery, flexible manufacturing systems, Petri nets
In the flexible manufacturing system deadlock prevention domain, researchers’ almost final target is to seek the maximally permissive controllers for solving the deadlock problems of flexible manufacturing systems. However, it seems a challenging work. Whatever you adopt, what kinds of methods, policies, and strategies, it seems complicated to obtain optimal controllers for deadlock prevention even if they claim their algorithms are optimal until the deadlock recovery is developed. Therefore, many experts, including us, have decided to design all kinds of actual maximally permissive recovery policies based on control transitions. It is a pity that these policies usually solve some particular flexible manufacturing systems’ deadlock problems. The controllers failed to recover the deadlock situation of flexible manufacturing systems once the idle or resource places were changed. In other words, these policies could never know or identify the real number of maximally permissive controller... [more]
Fault Diagnosis Based on Fusion of Residuals and Data for Chillers
Zhanwei Wang, Boyang Liang, Jingjing Guo, Lin Wang, Yingying Tan, Xiuzhen Li, Sai Zhou
September 20, 2023 (v1)
Keywords: chillers, data, fault diagnosis, fusion, residual
Feature data refer to direct measurements of specific features, while feature residuals represent the deviations between these measurements and their corresponding benchmark values. Both types of information offer unique insights into the system’s behavior. However, conventional diagnostic systems often struggle to effectively integrate and utilize both types of information concurrently. To address this limitation and improve diagnostic performance, a hybrid method based on the Bayesian network (BN) is proposed. This method enables the parallel fusion of feature residuals and feature data within a unified diagnostic model, and a comprehensive framework for developing this hybrid method is also given. In the hybrid BN, the symptom layer consists of residual nodes representing feature residuals and data nodes representing measured feature data. By applying the proposed method to two chillers and comparing it with state-of-the-art existing methods, we demonstrate its effectiveness and sup... [more]
Nonlinear Adaptive Generalized Predictive Control for PH Model of Nutrient Solution in Plant Factory Based on ANFIS
Yonggang Wang, Ning Zhang, Chunling Chen, Yingchun Jiang, Tan Liu
September 20, 2023 (v1)
Keywords: adaptive neuro-fuzzy inference system (ANFIS), generalized predictive control (GPC), nonlinear adaptive control, nutrient solution, pH control, plant factory
A plant factory is typically considered to be an exceedingly advanced product management system characterized by higher crop yields and better quality control. The pH value of the nutrient solution is crucial for determining the health and productivity of crops. However, the nutrient solution process exhibits inherent complexity, such as parameters uncertainty, multi-disturbances, and strong nonlinearity. Therefore, the traditional control method cannot meet the necessary requirements. The main objective of this paper is to address the issues of parameter uncertainty, strong nonlinearity, and multiple disturbances in the regulation process of the nutrient solution while achieving accurate control of the nutrient solution pH in a plant factory. This is performed so that a dynamic model of a nutrient solution for pH is developed and a nonlinear adaptive controller is presented, which comprises a linear adaptive generalized predictive controller, a nonlinear adaptive generalized predictiv... [more]
Factors That Control the Reservoir Quality of the Carboniferous−Permian Tight Sandstones in the Shilounan Block, Ordos Basin
Jing Wang, Fawang Ye, Chuan Zhang, Zhaodong Xi
September 20, 2023 (v1)
Keywords: diagenesis, pore structure, porosity, reservoir, tight sandstone gas
The Carboniferous−Permian, coal-bearing, sedimentary succession on the eastern edge of the Ordos Basin in the Shilounan Block contains large accumulations of hydrocarbon resources. During the exploration of coalbed methane and tight sandstone gas in the study area, multiple drilling wells in the tight sandstone reservoirs have yielded favorable gas logging results. The Benxi, Taiyuan, Shanxi, Shihezi, and Shiqianfeng formations contain multiple sets of sandstone reservoirs, and the reservoir quality and the controlling factors of its tight sandstones were affected by sedimentation, diagenetic alteration, and pore structure. This study comprehensively examines the sedimentary environment, distribution of sand bodies, and physical characteristics of tight sandstone reservoirs through drilling, coring, logging, and experimental testing. The results indicate that the Carboniferous−Permian tight sandstones are mainly composed of lithic sandstone and lithic quartz sandstone. The reservoir qu... [more]
Intelligent Control of Wastewater Treatment Plants Based on Model-Free Deep Reinforcement Learning
Oscar Aponte-Rengifo, Mario Francisco, Ramón Vilanova, Pastora Vega, Silvana Revollar
September 20, 2023 (v1)
Keywords: intelligent control, model-free deep reinforcement learning, reusing policy, waste water treatment plant
In this work, deep reinforcement learning methodology takes advantage of transfer learning methodology to achieve a reasonable trade-off between environmental impact and operating costs in the activated sludge process of Wastewater treatment plants (WWTPs). WWTPs include complex nonlinear biological processes, high uncertainty, and climatic disturbances, among others. The dynamics of complex real processes are difficult to accurately approximate by mathematical models due to the complexity of the process itself. Consequently, model-based control can fail in practical application due to the mismatch between the mathematical model and the real process. Control based on the model-free reinforcement deep learning (RL) methodology emerges as an advantageous method to arrive at suboptimal solutions without the need for mathematical models of the real process. However, convergence of the RL method to a reasonable control for complex processes is data-intensive and time-consuming. For this rea... [more]
Estimating APC Model Parameters for Dynamic Intervals Determined Using Change-Point Detection in Continuous Processes in the Petrochemical Industry
Yoseb Yu, Minyeob Lee, Chaekyu Lee, Yewon Cheon, Seungyun Baek, Youngmin Kim, Kyungmin Kim, Heechan Jung, Dohyeon Lim, Hyogeun Byun, Jongpil Jeong
September 20, 2023 (v1)
Keywords: advanced process control, change-point detection, continuous process, model parameter estimation, petrochemical
Several papers have proven that advanced process controller (APC) systems can save more energy in the process than proportional-integral-differential (PID) controller systems. Therefore, implementing an APC system is ultimately beneficial for saving energy in the plant. In a typical APC system deployment, the APC model parameters are calculated from dynamic data intervals obtained through the plant test. However, depending on the proficiency of the APC engineer, the results of the plant test and the APC model parameters are implemented differently. To minimize the influence of the APC engineer and calculate universal APC model parameters, a technique is needed to obtain dynamic data without a plant test. In this study, we utilize time-series data from a real petrochemical plant to determine dynamic intervals and estimate APC model parameters, which have not been investigated in previous studies. This involves extracting the data of the dynamic intervals with the smallest mean absolute... [more]
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