Browse
Subjects
Records with Subject: Optimization
Showing records 1 to 25 of 1511. [First] Page: 1 2 3 4 5 Last
Low-Carbon Economic Dispatch of Electricity and Cooling Energy System
Yubo Wang, Ling Hao, Libin Zheng, Lei Chen, Fei Xu, Qun Chen, Yong Min
February 10, 2024 (v1)
Subject: Optimization
Keywords: building thermal inertia, carbon trading mechanism, elastic thermal comfort, electric-cooling dispatch, pipeline thermal characteristics
In response to the issue of the hydropower consumption of run-of-river hydropower stations in Southwest China, the district cooling system can provide regulation capacity for hydropower utilization and suppress fluctuations caused by the uncertainty of hydropower. The innovative method is to utilize the thermal characteristics of pipelines and buildings, as well as the thermal comfort elasticity to shift the cooling and electricity loads, which helps to consume the surplus hydroelectric power generation. Taking the minimum total cost of coal consumption in thermal power units, hydropower abandonment penalty, and the carbon trading cost as the objective function, models were established for power supply balance constraints, heat transport constraints, and unit output constraints. The hybrid integer linear programming algorithm was used to achieve the low-carbon economic dispatch of the electric-cooling system. The calculation examples indicate that compared to the traditional real-time... [more]
Stick−Slip Characteristics of Drill Strings and the Related Drilling Parameters Optimization
Chao Wang, Wenbo Chen, Zhe Wu, Jun Li, Gonghui Liu
February 10, 2024 (v1)
Subject: Optimization
Keywords: drill string, drilling parameter, Optimization, stick–slip vibration
To eliminate or reduce stick−slip vibration in torsional vibration of the drilling string and improve the rate of penetration (ROP), a stick−slip vibration model of the drilling string considering the ROP was established based on the multidimensional torsional vibration model of the drilling string. The model was verified by simulation analysis. The characteristics of the drilling string stick−slip vibration in the three stages of stationary, slip, and stick were analyzed. This paper investigated the influence of rotary torque, rotary speed, and weight on bit (WOB) on stick−slip vibrations in the drill string. Based on this, the relationship between the drilling parameters and ROP was established. Drilling parameter optimization was completed for soft, medium-hard, and hard formations. Results showed that appropriately increasing torque and decreasing WOB can reduce or even eliminate stick−slip vibrations in the drill string and increase the ROP. The parameter optimization increased th... [more]
Prediction of Lost Circulation in Southwest Chinese Oil Fields Applying Improved WOA-BiLSTM
Xianming Liu, Wen Jia, Zhilin Li, Chao Wang, Feng Guan, Kexu Chen, Lichun Jia
February 10, 2024 (v1)
Subject: Optimization
Keywords: Bidirectional Long Short Term Memory, correlation analysis, improved whale optimization algorithm, lost circulation prior to drilling, prediction model
Drilling hazards can be significantly decreased by anticipating potential mud loss and then putting the right well control measures in place. Therefore, it is critical to provide early estimates of mud loss. To solve this problem, an enhanced WOA (Whale Optimization Algorithm) and a BiLSTM (Bidirectional Long Short Term Memory) optimization based prediction model of lost circulation prior to drilling has been created. In order to minimize the noise in the historical comprehensive logging data, a wavelet filtering technique was first used. Then, according to the nonlinear Spearman rank correlation coefficient between mud loss and logging parameter values from large to small, seven characteristic parameters were preferred, and the sliding window was used to extract the relevant data. Secondly, the number of neurons in the first and second hidden layers, the maximum training time, and the initial learning rate of the BiLSTM model were optimized using the enhanced WOA method. The BiLSTM ne... [more]
Coal and Gas Outburst Prediction Model Based on Miceforest Filling and PHHO−KELM
Liangshan Shao, Wenjing Chen
February 10, 2024 (v1)
Subject: Optimization
Keywords: coal and gas outburst prediction, Harris Hawk optimization algorithm with Piecewise chaotic mapping, kernel extreme learning machine, missing data filling, multiple filling of chained equations for random forests
Coal and gas outbursts are some of the most serious coal mine disasters, and effective prediction of coal and gas outbursts can reduce the likelihood of accidents and fatalities. Previously conducted studies have established that machine learning has achieved results in the prediction of coal and gas outbursts, but there is a problem that the available accident data of coal and gas outbursts are diminished or missing. This paper proposes a prediction model based on multiple filling of chained equations for random forests (miceforest) and the Harris Hawk optimization algorithm with Piecewise chaos mapping (PHHO) to optimize the kernel extreme learning machine (KELM) to solve the problem of missing data in coal and gas outburst prediction and to improve prediction accuracy in the case of missing data. Firstly, the miceforest algorithm was adopted to fill missing values in the salient samples, and then the PHHO algorithm was used to optimize the parameters of KELM. Finally, the datasets b... [more]
Redox Performance and Optimization of the Chemical Composition of Lanthanum−Strontium−Manganese-Based Perovskite Oxide for Two-Step Thermochemical CO2 Splitting
Hiroki Sawaguri, Daichi Yasuhara, Nobuyuki Gokon
February 10, 2024 (v1)
Subject: Optimization
Keywords: CO2 splitting, concentrated solar radiation, perovskite oxide, redox oxides, solar fuel, thermal stability, thermochemical cycle, X-ray photoelectron spectroscopy
The effects of substitution at the A- and B sites on the redox performance of a series of lanthanum−strontium−manganese (LSM)-based perovskite oxides (Z = Ni, Co, and Mg) were studied for application in a two-step thermochemical CO2 splitting cycle to produce liquid fuel from synthesis gas using concentrated solar radiation as the proposed energy source and CO2 recovered from the atmosphere as the prospective chemical source. The redox reactivity, stoichiometry of oxygen/CO production, and optimum chemical composition of Ni-, Co-, and Mg-substituted LSM perovskites were investigated to enhance oxygen/CO productivity. Furthermore, the long-term thermal stabilities and thermochemical repeatabilities of the oxides were evaluated and compared with previous data. The valence changes in the constituent ionic species of the perovskite oxides were studied and evaluated by X-ray photoelectron spectroscopy (XPS) for each step of the thermochemical cycle. From the perspectives of high redox react... [more]
Topology Structural Design and Thermal Characteristics Analysis of High-Efficiency Heat Conductive Path for the Spindle System
Yang Li, Zhongting Liu, Lei Li, Wenlei He, Zhaoyang Hou, Wanhua Zhao, Wenwu Wu
January 12, 2024 (v1)
Subject: Optimization
Keywords: continuum structure, heat conductive path, machine tool error, topology optimization
In order to enhance the heat dissipation of the spindle under working condition, thermal conductivity paths were designed based on the topology optimization method. The heat conductive path was proposed to be constructed in the bearing housing and the spindle housing, which was simplified as a toroidal model. Taking the heat dissipation weakness as the optimization objective, the topological structure with the highest thermal conductivity was obtained based on the OC and IPTO algorithms. In order to analyze the influence of the heat conductive path on the circumferential heat distribution of the spindle, the thermal characteristic of the model with heat conductive paths filled with copper was investigated. Compared with the general model, the heat conductive path could reduce the temperature of the spindle from 47 °C to 33 °C when the volume proportion of the high thermal conductivity material was 40%. At the same time, the strength of the heat conductive path was analyzed, and the siz... [more]
Optimization of Batch Crystallization of Magnetic Lysozyme Crystals and Study of the Continuous Crystallization Process
Shanshan Yang, Lixia Hou, Min Su
January 12, 2024 (v1)
Subject: Optimization
Keywords: continuous crystallisation, lysozyme, magnetic, tubular
Protein crystallization is a widely employed technique for purifying protein drugs, offering notable benefits such as cost-effectiveness and high purity. However, the success of this method is influenced by factors such as the molecular weight and spatial structure of proteins. The challenges associated with achieving crystallization and the prolonged duration required for crystallization induction pose limitations on its widespread industrial implementation. In this study, we employed lysozyme derived from egg white as a representative protein to investigate the polymer-assisted self-assembly of magnetic lysozyme. Through the optimization of the initial interstitial crystallization process of magnetic lysozyme, we manipulated the supersaturation level of lysozyme and applied magnetic nanoparticle treatment. As a result, we successfully reduced the crystallization time from 24 h to 60 min. Subsequently, the findings derived from the analysis of data pertaining to the interstitial cryst... [more]
Process Optimization of Sea Buckthorn Fruit Powder Effervescent Tablets by Random Centroid Methodology Combined with Fuzzy Mathematical Sensory Evaluation
Yan Ma, Yali Lian, Xintao Meng, Mingqiang Xu, Ting Zhang, Hui Zou, Haiyan Yang
January 12, 2024 (v1)
Subject: Optimization
Keywords: effervescent tablet, random centroid methodology, sea buckthorn fruit powder, sensory evaluation
Solid beverages of effervescent tablets have good taste and portable features and are favored by consumers, but product quality and nutrition cannot meet the need of increasing nutritional requirements. Sea buckthorn fruit has a special flavor and nutrient-rich characteristics, but the related products of effervescent tablets have not been developed. In this paper, different additive contents (sea buckthorn fruit powder, erythritol, disintegrant, maltodextrin, polyvinylpyrrolidone (PVP)) were optimized using the random centroid method; the obtained effervescent effect sensory evaluation characteristics (appearance, beverage, appearance, taste, solubility) were used to establish a fuzzy mathematic model for sensory evaluation method of process optimizing; and the nutritional components and characteristics of optimized sea buckthorn powder effervescent tablets were compared to the ones of the commercial product. The results show that the optimal process conditions (47.7% sea buckthorn fr... [more]
Exploring Bayesian Optimization for Photocatalytic Reduction of CO2
Yutao Zhang, Xilin Yang, Chengwei Zhang, Zhihui Zhang, An Su, Yuan-Bin She
January 12, 2024 (v1)
Subject: Optimization
Keywords: Bayesian optimization, design of experiment, Machine Learning, photocatalytic reduction, reaction optimization
The optimization of photocatalysis is complex, as heterogenous catalysis makes its kinetic modeling or design of experiment (DOE) significantly more difficult than homogeneous reactions. On the other hand, Bayesian optimization (BO) has been found to be efficient in the optimization of many complex chemical problems but has rarely been studied in photocatalysis. In this paper, we developed a BO platform and applied it to the optimization of three photocatalytic CO2 reduction systems that have been kinetically modeled in previous studies. Three decision variables, namely, partial pressure of CO2, partial pressure of H2O, and reaction time, were used to optimize the reaction rate. We first compared BO with the traditional DOE methods in the Khalilzadeh and Tan systems and found that the optimized reaction rates predicted by BO were 0.7% and 11.0% higher, respectively, than the best results of optimization by DOE, and were significantly better than the original experimental data, which we... [more]
Special Issue on “Machine-Learning-Assisted Intelligent Processing and Optimization of Complex Systems”
Xiong Luo, Manman Yuan
November 30, 2023 (v1)
Subject: Optimization
Complex systems and their various characteristics have been widely considered in economic and industrial systems [...]
An Amended Crow Search Algorithm for Hybrid Active Power Filter Design
Shoyab Ali, Annapurna Bhargava, Akash Saxena, Abdulaziz S. Almazyad, Karam M. Sallam, Ali Wagdy Mohamed
November 30, 2023 (v1)
Subject: Optimization
Keywords: crow search algorithm, design, filter, numerical optimization, power quality, swarm intelligence
Hybrid Active Power Filter (HAPF) imbibes the advantages of both passive and active power filters. These filters are considered one of the important technologies for mitigating harmonic pollution in electrical systems. Accurate estimation of filter parameters is a key component to reduce harmonic pollution effectively. In recent years, several optimization approaches have been reported to solve this estimation problem; still, this area is worthy of further investigation. This paper is a proposal for an estimator that can estimate the parameter of HAPF configuration accurately. For evolving this estimator, first, an objective function that mathematically embeds filter parameters and harmonic pollution is presented. For handling the optimization process, an Amended Crow Search Algorithm (ACSA) is proposed. ACSA employs a local search algorithm (in the form of a pattern search) for obtaining optimal results. The analysis of the estimation process is carried out on two HAPF configurations.... [more]
Multi-Objective Optimization of a Novel Ribbed Honeycomb Heat Sink for an Electro-Hydrostatic Actuator
Yanpeng Li, Huijun Han, Mingzhong Li, Jinhu Zhang, Youwang Xing, Sheng Lei, Xiang Yu
November 30, 2023 (v1)
Subject: Optimization
Keywords: electro-hydrostatic actuator, heat sink, multi-objective particle swarm optimization
The electro-hydrostatic actuator (EHA) is a new type of power-by-wire (PBW) actuation system, which is utilized to realize a more electric aircraft. However, EHA suffers from serious thermal problems, due to its high integration and high power density. Therefore, a reasonable heat dissipation structure is an essential method for solving this problem. In this paper, a novel ribbed honeycomb heat sink (RHCS) developed by combining a ribbed heat sink (RHS) with a honeycomb heat sink (HCS) is proposed. Moreover, the optimization of heat sink parameters was achieved by using a multi-objective particle swarm optimization algorithm (MOPSO). Initially, the thermal resistance and mass models of the HCS were constructed, based on which the optimal structural parameters of the honeycomb cell were obtained. In addition, the thermal resistance model of RHCS was constructed using the response surface method, and parameters such as rib spacing, height and width were obtained based on MOPSO. Finally,... [more]
Gangue Source Reduction Technology and Process Optimization Based on Underground Coal Gangue Photoelectric Separation
Wei Zhou, Wanghao Xia, Liangliang Liu, Liansheng Li, Qiuyu Zeng, Shujie Wang, Jinbo Zhu
November 30, 2023 (v1)
Subject: Optimization
Keywords: coal gangue photoelectric sorting, gangue source reduction, jet separation, process layout, underground gangue discharge
The precise identification of damp, sticky coal gangue; efficient jet nozzle separation; and process layout in a narrow, restricted space are essential technologies for gangue source reduction based on underground gangue photoelectric separation, which is critical for the long-term growth of coal mines. In this paper, the X-ray absorption fine structure (XAFS) method was used to identify the X-ray absorption law of different atoms in coal-based minerals and explore the differences in the microscopic crystal properties of coal gangue; the numerical simulation calculation of four commonly used nozzles—namely, flat, convergent, flat−convergent, and streamline—was carried out using Fluent software for coal gangue jet separation to optimize the nozzle morphology and parameters. The technical characteristics of the underground layout of the photoelectric separation system for coal gangue were expounded, and the technological layout of the separation system was explored. The results showed th... [more]
Optimization of Cost−Carbon Reduction−Technology Solution for Existing Office Parks Based on Genetic Algorithm
Zhenlan Dou, Lu Jin, Yinhui Chen, Zishuo Huang
September 21, 2023 (v1)
Subject: Optimization
Keywords: carbon reduction, cost benefits, existing office parks, Genetic Algorithm, retrofit, whole life cycle
With limited investment costs, how to fully utilize the carbon-reduction capacity of a campus in terms of buildings, equipment, and energy is an important issue when realizing the low-carbon retrofit of office parks. To this end, this paper establishes a mathematical optimization model for the decarbonization-based retrofit of existing office parks, based on the genetic algorithm, taking into account the relationship between cost, energy-consumption, and carbon-emissions, and taking the maximum carbon reduction of the park over its whole life as the optimization goal. The validity of the model was verified in conjunction with a case study of an office park in Nanchang, China. The case study shows that, compared with current typical parks, the carbon reduction through an office park’s decarbonization retrofit has a non-linear correlation with the investment cost, and when the total investment cost of the park is above CNY 60 million, the increase in carbon reduction with the increase in... [more]
Optimization Study of Inert Gas Distribution for Multiple-Bay Fuel Tank
Lei Shao, Jiawei He, Xia Lu, Weihua Liu
September 21, 2023 (v1)
Subject: Optimization
Keywords: inerting system, optimization scheme, TOPSIS method, ventilation mode
Inert gas distribution has a great influence on the inerting effect, especially for the multiple-bay fuel tank. In order to find out the optimal scheme, an optimization method based on the entropy-weight improvement TOPSIS method is proposed, and an experimental system of inert gas distribution is established to measure the speed index and uniformity index. The results show that the position of the inlet and outlet has a significant effect on the overall inerting effect. The inerting scheme designed by the entropy-weight improvement TOPSIS method can not only reduce the flow demand of inert gas but also make the oxygen distribution more uniform. The optimization inerting scheme of the Boeing 747 aircraft has improved the average speed index by 3.01% and the average uniformity index by 26.18%. The smoke visualization experiment also showed that the scheme designed by the entropy-weight improvement TOPSIS method has the denser white smoke, which means that the scheme has better performan... [more]
Numerical Optimization Study of the Resistance Coefficient of U-Shaped Air Distributor
Zhijing Wu, Jinfeng Wang, Jing Xie
September 21, 2023 (v1)
Subject: Optimization
Keywords: air distributor, flow channel structure, orthogonal test design, pressure loss, resistance coefficient
In this paper, the optimization of the flow channel structure of the U-shaped air distributor is proposed. Fluent meshing was used to mesh the multipatch meshing of the original model of the grid air distributor, and then the CFD numerical simulation was carried out by using Fluent 2022R1 to obtain the internal air flow state of the air distributor flow channel. Through the orthogonal experimental design and a comprehensive analysis method, the optimal size structure for resistance performance is obtained as S = 60 mm, RL = 125 mm, L = 160 mm, D = 100 mm, the resistance coefficient of the new structure as 1.375, and the pressure loss as 56.87 Pa, by using 3D modeling software (SOLIDWORKS 2015) and Fluent. Compared with the initial scheme, the resistance coefficient and pressure loss are reduced by 3.03% and 6.29%, respectively. To summarize, the research in this paper offers a substantial contribution to the realm of energy conservation and emission abatement in ship air conditioning s... [more]
Multi-Response Optimization Analysis of the Milling Process of Asphalt Layer Based on the Numerical Evaluation of Cutting Regime Parameters
Teodor Dumitru, Marius Gabriel Petrescu, Maria Tănase, Costin Nicolae Ilincă
September 21, 2023 (v1)
Subject: Optimization
Keywords: ANOVA, asphalt concrete, chip section area, cutting forces, DEM, DOE, GRA, milling teeth, Optimization
The present study aimed to optimize the process parameters (milling depth and advanced speed) for an asphalt milling operation using a multi-response approach based on Taguchi design of experiments (DOE) and Grey Relational Analysis (GRA). Nine simulations tests were conducted using Discrete Element Method (DEM) in order to determine the forces acting on the cutting tooth support and tip. The considered performance characteristics were cutting forces (smaller is better category) and chip section area (larger is better category). A Grey Relational Grade (GRG) was determined from GRA, allowing to identify the optimal parameter levels for the asphalt milling process with multiple performance characteristics. It was found that that the optimal milling parameters for multi-response analysis are a milling depth of 200 mm and an advanced speed of 30 mm/min. Furthermore, analysis of variance (ANOVA) was used to determine the most significant factor influencing the performance characteristics.... [more]
A Comprehensive Asset Evaluation Method for Oil and Gas Projects
Muzhen Zhang, Ailin Jia, Zhanxiang Lei, Gang Lei
September 21, 2023 (v1)
Subject: Optimization
Keywords: asset comprehensive evaluation method, asset grading and ranking, cloud model, linear weighted, new oil and gas field project
The rapid and accurate evaluation of oil and gas assets, specifically for new development projects, poses a significant challenge due to the various project types, limited data availability, brief periods for assessment and decision making, and constraints arising from varying contractual and taxation conditions, political stability, and societal factors. This study leverages the grading standards of the evaluation index system for new oil and gas field development projects, along with relevant mathematical theories and methods for project evaluation and optimization. We developed an asset evaluation approach for new oil and gas projects by analyzing the assets of six new oil and gas field development projects in Brazil. This analysis resulted in the grading and ranking of new projects, and we tested and demonstrated four asset optimization techniques. After a comparative analysis with conventional evaluation results, we established an oil and gas project asset optimization approach ce... [more]
The Characteristics of Fracturing Fluid Distribution after Fracturing and Shut-In Time Optimization in Unconventional Reservoirs Using NMR
Xin Huang, Lei Wang, Nan Wang, Ming Li, Shuangliang Wu, Qun Ding, Shucan Xu, Zhilin Tuo, Wenqiang Yu
September 21, 2023 (v1)
Subject: Optimization
Keywords: distribution characteristics, fracturing fluid, NMR, post-fracturing shut-in, shut-in duration, unconventional reservoir
Post-fracturing shut-in, as an important means of improving the energy efficiency of fracturing fluid, has been widely used in the development process of unconventional reservoirs. The determination of the shut-in duration is key to the effectiveness of shut-in measures. However, the distribution characteristics of the fracturing fluid during the post-fracturing shut-in period in unconventional reservoirs, such as the Chang 7 reservoir, were not clear, and the shut-in duration needed further optimization. Therefore, this paper employed low-field nuclear magnetic resonance (NMR) technology to study the distribution characteristics of the fracturing fluid during the post-fracturing shut-in period in unconventional reservoirs and optimized the shut-in duration. The study showed that the Chang 7 reservoir had a complex pore structure and relatively low porosity and permeability. During the shut-in process, the filtrate was distributed in pore throats with radii ranging from 0.0012 μm to 0.... [more]
Improved Faster R-CNN Network for Liquid Bag Foreign Body Detection
Bo Huang, Jianhong Liu, Qian Zhang, Kang Liu, Xiang Liu, Jian Wang
September 21, 2023 (v1)
Subject: Optimization
Keywords: attention mechanism, Faster R-CNN, feature fusion, foreign body detection, K-means, ResNet152
The production quality of medical fluid bags is closely related to patient health. In this paper, we used medical fluid bags to detect whether they contained foreign bodies. A visual acquisition system for the fluid bag was built. Vignetting correction was performed on the acquired images, and a foreign body recognition detection method based on an improved Faster R-CNN model was proposed. The feature extraction network of Faster R-CNN was discussed and studied regarding the characteristics of small foreign objects in liquid bags, and the ResNet152 network replaced the VGG16 network; furthermore, the feature fusion and attention mechanism were added to the feature extraction, and CIoU replaced the IoU loss function; the anchor box parameters were optimized and improved using the K-means clustering algorithm, and ROI Align replaced the ROI Pooling module. The improved network in this paper was compared with the Faster R-CNN model, which is a modification of feature extraction networks,... [more]
Hydrodistillation and Steam Distillation of Fennel Seeds Essential Oil: Parameter Optimization and Application of Cryomilling Pretreatment
Nina Marčac, Sandra Balbino, Petra Tonković, Ana Marija Medved, Ena Cegledi, Sanja Dragović, Verica Dragović-Uzelac, Maja Repajić
September 21, 2023 (v1)
Subject: Optimization
Keywords: cryogenic grinding, essential oil isolation, Foeniculum vulgare Mill., optimal conditions, volatiles, yield
The aim of this study was to examine the effectiveness of cryomilling (CM) pretreatment on the isolation of fennel seeds essential oil (EO). Therefore, the study included (i) the process optimization and comparison of the efficiencies of hydrodistillation (HD) and steam distillation (SD); (ii) the evaluation of the effect of the CM application prior to the distillation method (selected based on the results obtained in the first part) on the EO yield; (iii) the evaluation of possible quality differences of the EOs obtained with the performed isolation methods. The obtained results showed that HD (at a solid to liquid ratio 1:10 and a distillation time of 120 min) was more efficient in terms of the EO yield compared to SD (at a pressure of 0.83 bar and distillation time of 117 min as optimal conditions). Moreover, an increased EO yield or even reduced distillation time was observed when HD was combined with a 3 min or 5 min CM pretreatment. GC-MS analysis showed no qualitative difference... [more]
First Law Optimization and Review of Double and Triple-Effect Parallel Flow Vapor Absorption Refrigeration Systems
Md. Azhar
September 20, 2023 (v1)
Subject: Optimization
Keywords: Optimization, parallel flow, thermodynamic analysis, triple effect, vapor absorption refrigeration system
Parallel flow double and triple-effect vapor absorption cooling systems (VACS) are trying to meet the challenges of vapor compression cooling systems due to their better performance. Therefore, the present study deals with the review, thermodynamic analysis, and optimization of operating parameters for both double and triple-effect VACS. Lithium bromide water was selected as the working fluid, while liquified petroleum gas (LPG) and compressed natural gas (CNG) were taken as the source of energy to drive both the VACS. Detailed First Law analysis, i.e., coefficient of performance (COP), was examined along with the optimization of operating parameters (such as salt concentration and operating generators temperature at different pressure levels) and the volume flow rate of the gases. Optimization was carried out for maximum COP of the VACS using an iterative technique. Our results show that the COP of the triple-effect system was approximately 32% higher than the double effect, while 15−... [more]
A Two-Stage Optimal Preventive Control Model Incorporating Transient Stability Constraints in the Presence of Multi-Resource Uncertainties
Qiulong Ni, Jingliao Sun, Xianyu Zha, Taibin Zhou, Zelun Sun, Ming Zhao
September 20, 2023 (v1)
Subject: Optimization
Keywords: multi-resource uncertainties, particle swarm algorithm, preventive control, transient stability constraints, two-stage model
The volatility and uncertainty introduced by increasingly integrated renewable energy pose challenges to the reliable and stable operation of the power system. To mitigate the operation risks, a two-stage optimal preventive control model that incorporates transient stability constraints and considers uncertainties from multiple resources is proposed. First, the uncertainties of different re-sources are modeled, with which the non-sequential Monte Carlo sampling method is used to correspondingly generate the scenarios. Thereafter, a two-stage control model that balances operational safety and economy and realizes preventive control and emergency control is built. The operation schedule from the preventive control stage aims to minimize the transient stability probability and operation costs. If any faults destabilize the system, the emergency control stage will be activated immediately to help the system recover stability with minimal control costs. To expedite the solving of the two-st... [more]
Cluster Optimization for Integrated Energy Systems Considering Multi-Energy Sharing and Asymmetric Profit Allocation: A Case Study of China
Shiting Cui, Peng Wang, Yao Gao, Ruijin Zhu
August 3, 2023 (v1)
Subject: Optimization
Keywords: asymmetric profit allocation, electricity, heat and oxygen coupling, IES cluster optimization, multi-energy sharing, Nash game
This study proposes a novel integrated energy system (IES) cluster optimization structure that uses multi-energy sharing, multi-Nash games, and asymmetric profit allocation according to the energy supply demand and energy development planning for Tibet. First, it integrates clean energy units such as concentrated solar power, power to hydrogen to power, and vacuum pressure swing adsorption to build a novel IES including electricity, heat, and oxygen. Second, multiple novel IESs are combined to form an IES cluster and the IES cluster is divided into three stages of optimization: the first stage is to achieve optimal multi-energy sharing under cluster optimization, the second stage is to conduct multi-Nash games to achieve optimal sharing cost, and the third stage is to conduct asymmetric profit allocation. Finally, the case study is conducted and the results show that the multi-Nash games and asymmetric profit allocation can effectively improve the renewable energy consumption of the IE... [more]
Optimization of Supercritical Carbon Dioxide Fluid Extraction of Medicinal Cannabis from Quebec
Hinane Boumghar, Mathieu Sarrazin, Xavier Banquy, Daria C. Boffito, Gregory S. Patience, Yacine Boumghar
August 3, 2023 (v1)
Subject: Optimization
Keywords: Box–Behnken, cannabinoids, Optimization, supercritical carbon dioxide
Research on cannabis oil has evolved to encompass the pharmaceutical industry for the therapeutic potential of the active compounds for pathologies such as Alzheimer, auto-immune disorders, and cancer. These debilitating diseases are best treated with cannabinoids such as tetrahydrocannabinol (∆9-THC), cannabigerol (CBG), and cannabinol (CBN), which relieve neuropathic pain and stimulate the immune system. We extracted cannabinoids from plants with supercritical CO2 and produced an extract with a total yield close to 26%. The three-level Box−Behnken experimental design considered four factors: Temperature, pressure, CO2 flow rate, and processing time, with predetermined parameters at low, medium, and high levels. The mathematical model was evaluated by regression analysis. The yield of ∆9-THC and CBG reached a maximum after 2 h and 15 g/min of CO2, 235 bar, 55 °C (64.3 g THC/100 g of raw material and 4.6 g CBG/100 g of raw material). After another 2 h of extraction time, the yield of C... [more]
Showing records 1 to 25 of 1511. [First] Page: 1 2 3 4 5 Last
[Show All Subjects]