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Records added in August 2024
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26. LAPSE:2024.1980
Green Supply Chain Optimization Based on Two-Stage Heuristic Algorithm
August 28, 2024 (v1)
Subject: Planning & Scheduling
Keywords: brainstorming optimization algorithm, green supply chain management, logistics planning, supply chain optimization
Green supply chain management is critical for driving sustainable development and addressing escalating environmental challenges faced by companies. However, due to the multidimensionality of cost−benefit analysis and the intricacies of supply chain operations, strategic decision-making regarding green supply chains is inherently complex. This paper proposes a green supply chain optimization framework based on a two-stage heuristic algorithm. First, anchored in the interests of intermediary core enterprises, this work integrates upstream procurement and transportation of products with downstream logistics and distribution. In this aspect, a three-tier green complex supply chain model incorporating economic and environmental factors is developed to consider carbon emissions, product non-conformance rates, delay rates, and transportation costs. The overarching goal is to comprehensively optimize the trade-off between supply chain costs and carbon emissions. Subsequently, a two-stage heur... [more]
27. LAPSE:2024.1979
Mus4mCPred: Accurate Identification of DNA N4-Methylcytosine Sites in Mouse Genome Using Multi-View Feature Learning and Deep Hybrid Network
August 28, 2024 (v1)
Subject: System Identification
Keywords: bioinformatics, deep learning, DNA N4-methylcytosine sites, feature fusion
N4-methylcytosine (4mC) is a critical epigenetic modification that plays a pivotal role in the regulation of a multitude of biological processes, including gene expression, DNA replication, and cellular differentiation. Traditional experimental methods for detecting DNA N4-methylcytosine sites are time-consuming, labor-intensive, and costly, making them unsuitable for large-scale or high-throughput research. Computational methods for identifying DNA N4-methylcytosine sites enable the rapid and cost-effective analysis of DNA 4mC sites across entire genomes. In this study, we focus on the identification of DNA 4mC sites in the mouse genome. Although there are already some computational methods that can predict DNA 4mC sites in the mouse genome, there is still significant room for improvement in accurately predicting them due to their inability to fully capture the multifaceted characteristics of DNA sequences. To address this issue, we propose a new deep learning predictor called Mus4mCP... [more]
28. LAPSE:2024.1978
Study of Draft Tube Optimization Using a Neural Network Surrogate Model for Micro-Francis Turbines Utilized in the Water Supply System of High-Rise Buildings
August 28, 2024 (v1)
Subject: Numerical Methods and Statistics
Keywords: draft tube, Francis turbine, high-rise buildings, radial basis function neural network, water supply system
With the increasing popularity of clean energy, the use of micro turbines to recover surplus energy in the water supply pipelines of high-rise buildings has attracted more attention. This study adopts a predictor model based on Radial Basis Function Neural Network (RBFNN) to optimize the draft tube shape for micro-Francis turbines. The predictor model is formed on a dataset provided by numerical simulations, which are validated by lab tests. Specifically, numerical investigations are carried out in the shape of a draft tube to determine an optimal model. Additionally, the superiority of the RBFNN model in nonlinear optimization is verified by comparing it with other models under the same date sets. After that, the design parameters are optimized using RBFNN and sequential quadratic programming algorithm (SQPA). Finally, the turbine prototype is fabricated and tested on a lab test rig. The experimental results indicate that the numerical method adopted in this research is accurate enoug... [more]
29. LAPSE:2024.1977
Assessment of Wearable Cooling and Dehumidifying System Used under Personal Protective Clothing through Human Subject Testing
August 28, 2024 (v1)
Subject: Process Design
Keywords: healthcare workers, personal protective equipment, thermal comfort, wearable cooling and dehumidifying system, wearing comfort
Healthcare professionals wearing personal protective equipment (PPE) during outbreaks often experience heat strain and discomfort, which can negatively impact their work performance and well-being. This study aimed to evaluate the physiological and psychological effects of a newly designed wearable cooling and dehumidifying system (WCDS) on healthcare workers wearing PPE via a 60 min treadmill walking test. Core temperature, mean skin temperature, heart rate, and subjective assessments of thermal sensation, wetness sensation, and thermal comfort were measured throughout the test. Additionally, ratings of wearing comfort and movement comfort were recorded during a wearing trial. The results showed that the WCDS significantly reduced core temperature, improved thermal sensation, and reduced wetness sensation compared to the non-cooling condition. The microclimatic temperature within the PPE was significantly lower in the cooling condition, indicating the WCDS’s ability to reduce heat bui... [more]
30. LAPSE:2024.1976
Experimental Analysis of the Mechanical Properties and Failure Behavior of Deep Coalbed Methane Reservoir Rocks
August 28, 2024 (v1)
Subject: Materials
Keywords: compressive strength of rock, deep coalbed methane reservoir, failure behavior, kaolinite, rock mechanical properties
A comprehensive understanding of the mechanical characteristics of deep coalbed methane reservoir rocks (DCMRR) is crucial for the safe and efficient development of deep coalbed gas resources. In this study, the microstructural and mechanical features of the coal seam roof, floor, and the coal seam itself were analyzed through laboratory experiments. The impact mechanisms of drilling fluid and fracturing fluid hydration on the mechanical properties and failure behavior of coal seam rocks were investigated. The experimental results indicate that the main minerals in coal seams are clay and amorphous substances, with kaolinite being the predominant clay mineral component in coal seam rocks. The rock of the coal seam roof and floor exhibits strong elasticity and high compressive strength, while the rock in the coal seam section shows a lower compressive capacity with pronounced plastic deformation characteristics. The content of kaolinite shows a good correlation with the mechanical prope... [more]
31. LAPSE:2024.1975
Development of Macro-Encapsulated Phase-Change Material Using Composite of NaCl-Al2O3 with Characteristics of Self-Standing
August 28, 2024 (v1)
Subject: Materials
Keywords: encapsulated phase-change material, enhanced thermal conductivity, high durability, molten salt, self-standing
Developing thermal storage materials is crucial for the efficient recovery of thermal energy. Salt-based phase-change materials have been widely studied. Despite their high thermal storage density and low cost, they still face issues such as low thermal conductivity and easy leaks. Therefore, a new type of NaCl-Al2O3@SiC@Al2O3 macrocapsule was developed to address these drawbacks, and it exhibited excellent rapid heat storage and release capabilities and was extremely stable, significantly reducing the risk of leakage at high temperatures for industrial waste heat recovery and in concentrated solar power systems above 800 °C. Thermal storage macrocapsules consisted of a double-layer encapsulation of silicon carbide and alumina and a self-standing core of NaCl-Al2O3. After enduring over 1000 h at a high temperature of 850 °C, the encapsulated phase-change material exhibited an extremely low weight loss rate of less than 5% compared with NaCl@Al2O3 and NaCl-Al2O3@Al2O3 macrocapsules, for... [more]
32. LAPSE:2024.1974
Three-Dimensional Heterogeneous Salt Cavern Underground Gas Storage Water Solution Cavity Model Study
August 28, 2024 (v1)
Subject: Modelling and Simulations
Keywords: gas storage, morphology prediction, salt cavern, water-soluble cavity building model
In recent years, with the rapid development of salt cavern gas storage reservoir construction in China, the characteristics of salt rock reservoirs with strong non-homogeneity and many interlayers have brought challenges to the dynamic prediction of water solution cavity construction. Aiming to solve this problem, this paper constructs a three-dimensional non-homogeneous salt cavern reservoir water-soluble cavity building prediction model, which takes into full consideration the non-homogeneity of salt rock reservoirs, interlayers, reservoir temperatures, and water injection process parameters, among other factors. By comparing the calculation results of the software compiled by the model with those of other numerical simulation software, we show that the model can accurately reflect the influence of geological parameters on the cavity morphology under the condition of non-uniform geological parameters, with higher simulation accuracy, and ultimately analyze individual examples. It can... [more]
33. LAPSE:2024.1973
A Fractional Creep Model for Deep Coal Based on Conformable Derivative Considering Thermo-Mechanical Damage
August 28, 2024 (v1)
Subject: Materials
Keywords: conformable derivative, deep coal, fractional creep model, thermo-mechanical damage
In deep high-geostress and high-temperature environments, understanding the creep deformation of deep coal is of great significance for effectively controlling coal deformation and improving gas control efficiency. In this paper, the Abel dashpot is defined based on the conformable derivative, and a damage variable is introduced into the conformable derivative order, thereby constructing a damaged Abel dashpot. Combining the Weibull distribution and the Drucker−Prager yield criterion, the thermo-mechanical coupling damage variable is defined, and the coupling damage variable is introduced into the damaged Abel dashpot to establish a thermo-mechanical coupling damaged Abel dashpot. Based on the traditional framework of the Burgers creep model, a three-dimensional fractional creep model of deep coal considering the influence of thermo-mechanical coupling damage is proposed. Experimental data on coal creep under different temperatures and stress conditions are utilized to validate the eff... [more]
34. LAPSE:2024.1972
Bioprocess Design and Evaluation of Hydrothermal Hydrolysates from Sargassum sp. for Enhancing Arthrospira platensis Growth and Protein Content
August 28, 2024 (v1)
Subject: Process Design
Keywords: Biomass, biorefinery, blue biotechnology, circular bioeconomy, cyanobacteria, mixotrophic cultivation
The proliferation of Sargassum biomass in various coastal areas has led to environmental and socio-economic problems. However, due to their unique composition, these biomasses offer versatile applications, prompting research into their potential in third-generation biorefineries. In this study, the hydrothermal processing of Sargassum sp. was evaluated under specific conditions at 190 °C/50 min and 150 °C/30 min. The resulting hydrolysates (liquid phase) were used as alternative culture media for cultivation. Nine treatments for the cultivation of Arthrospira platensis were assessed, varying the concentration of hydrothermal hydrolysates (HH) at 190 °C/50 min: T1 (5% v/v), T2 (10% v/v), and T3 (15% v/v). T4 (5% v/v), T5 (10% v/v), and T6 (15% v/v), maintaining the same HH conditions, and with the addition of 0.7 g/L NaNO3; and treatments T7, T8, and T9 had concentrations of 5%, 10%, and 15% of HH, respectively, at 150 °C/30 min with the addition of 0.7 g/L NaNO3, respectively. Each tre... [more]
35. LAPSE:2024.1971
Research and Application of Non-Steady-State CO2 Huff-n-Puff Oil Recovery Technology in High-Water-Cut and Low-Permeability Reservoirs
August 28, 2024 (v1)
Subject: Materials
Keywords: CO2 huff-n-puff, low-permeability reservoir, non-steady state, on-site pilot test
In response to the issues of poor water flooding efficiency, low oil production rates, and low recovery rates during the high-water-cut period in the low-permeability reservoirs of the Mutou Oilfield, the non-steady-state (NSS) CO2 huff-n-puff oil recovery technology was explored. The NSS CO2 huff-n-puff can improve the development effect of low-permeability reservoirs by replenishing the reservoir energy and significantly increasing the crude oil mobility. Experimental investigations were carried out, including a crude oil and CO2−crude oil swelling experiment, minimum miscibility pressure testing experiment, high-temperature and high-pressure microfluidic experiment, and NSS CO2 huff-n-puff oil recovery on-site pilot test. The experimental results showed that the main mechanisms of NSS CO2 huff-n-puff include dissolution, expansion, viscosity reduction, and swept volume enlargement, which can effectively mobilize the remaining oil from the various pore throats within the reservoir. T... [more]
36. LAPSE:2024.1970
Bacteriostatic Activity of Janthinobacterium lividum and Purified Violacein Fraction against Clavibacter michiganensis
August 28, 2024 (v1)
Subject: Biosystems
Keywords: adenosine triphosphatase, ATP-ase, bacteriostatic activity, Clavibacter michiganensis, intermicrobial interactions, Janthinobacterium lividum, violacein
causes plant diseases and is included in the list of microorganisms subject to export control. Janthinobacterium lividum is capable of synthesizing a pigment with antagonistic potential. The purpose of the study was to evaluate the activity of J. lividum VKM B-3705D and the pigment fraction against C. michiganensis VKM Ac-1402. The results of spectrophotometric and nuclear magnetic resonance analysis showed that the pigment synthesized by the J. lividum VKM B-3705D corresponds to violacein. The J. lividum strain demonstrated potential bacteriostatic activity against C. michiganensis VKM Ac-1402 when both strains were co-cultured. Compared to the control (DMSO), the violacein solution suppressed the specific growth of Clavibacter by 57.7%. The mechanism of suppression of the growth of Clavibacter is discussed. One of the ways to suppress the growth of C. michiganensis may be the inhibition of key enzymes. Violacein inhibited the activity of adenosine triphosphatase (ATPase, EC 3.6.1.3)... [more]
37. LAPSE:2024.1969
Mechanism and Model Analysis of Ultralow-Temperature Fluid Fracturing in Low-Permeability Reservoir: Insights from Liquid Nitrogen Fracturing
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: cryogenic fluid, fracturing mode, gas transportation, liquid nitrogen fracturing mechanism, low-permeability reservoirs
Ultralow-temperature fluids (such as liquid nitrogen, liquid CO2) are novel waterless fracturing technologies designed for dry, water-sensitive reservoirs. Due to their ultralow temperatures, high compression ratios, strong frost heaving forces, and low viscosities, they offer a solution for enhancing the fracturing and permeability of low-permeability reservoirs. In this study, we focus on the combined effects of high-pressure fluid rock breaking, low-temperature freeze-thaw fracturing, and liquid-gas phase transformation expansion on coal-rock in low-permeability reservoirs during liquid nitrogen fracturing (LNF). We systematically analyze the factors that limit the LNF effectiveness, and we discuss the pore fracture process induced by low-temperature fracturing in coal-rock and its impact on the permeability. Based on this analysis, we propose a model and flow for fracturing low-permeability reservoirs with low-temperature fluids. The analysis suggests that the Leidenfrost effect an... [more]
38. LAPSE:2024.1968
Study on Pyrolysis Behavior of Avermectin Mycelial Residues and Characterization of Obtained Gas, Liquid, and Biochar
August 28, 2024 (v1)
Subject: Materials
Keywords: avermectin mycelial residues, biochar, nitrogen migration, pyrolysis
The proper disposal of antibiotic mycelial residue (AMR) is a critical concern due to the spread of antibiotics and environmental pollution. Pyrolysis emerges as a promising technology for AMR treatment. In this study, we investigated the effect of pyrolysis temperature on the thermal decomposition behavior and product characteristics of avermectin (AV) mycelial residues. Various characterization techniques were employed to analyze thoroughly the compositions and yields of the obtained gas, liquid, and biochar products. The results indicated that most of the organic matter such as protein, carbohydrate, and aliphatic compounds in AV mycelial residues decomposed intensely at 322 °C and tended to end at 700 °C, with a total weight loss of up to 72.6 wt%. As the pyrolysis temperature increased, the biochar yield decreased from 32.81 wt% to 26.39 wt% because of the enhanced degradation of volatiles and secondary reactions of the formed aromatic rings. Accordingly, more gas components were... [more]
39. LAPSE:2024.1967
Effect of Y2O3 Content on Microstructure and Wear Resistance of Laser Cladding Layer of Stellite-6 Alloy
August 28, 2024 (v1)
Subject: Materials
Keywords: abrasion resistance, high-speed steel, laser cladding, macroscopic morphology, microstructure
Laser cladding technology is an effective surface modification technique. In order to prepare coating with excellent properties on the surface of the cold heading die punch, stellite-6 cladding coating with different proportions of Y2O3 was prepared on the surface of W6Mo5Cr4V2 high-speed steel using laser cladding technology in this paper. The effects of different Y2O3 contents on the macroscopic morphology, microstructure, phase analysis, microhardness, and tribological properties of the stellite-6 coatings were investigated. It was determined that the optimal Y2O3 content for the stellite-6 powder was 2%. The results showed that the coating with 2%Y2O3 had the least number of pores and cracks and exhibited good surface flatness when joined. The microstructure became finer and denser, composed mainly of branch, cellular, equiaxed, and columnar grains. The coating consisted mainly of γ-Co, Fe-Cr, and Co3Fe7 strengthening phases, indicating good metallurgical bonding between the coatin... [more]
40. LAPSE:2024.1966
Sustainable Napier Grass (Pennisetum purpureum) Biochar for the Sorptive Removal of Acid Orange 7 (AO7) from Water
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: acid orange 7 (AO7), batch sorption, biochar, elephant grass, fixed-bed study, lignocellulosic waste, pyrolysis
The unregulated discharge of synthetic dyes from various anthropogenic and industrial activities has resulted in the contamination of different environmental compartments. These dyes can contaminate water bodies, soil, and even the air, resulting in many environmental and health issues. True colors may persist for long periods, thereby affecting the aesthetics and ecology of dye-contaminated areas. Furthermore, they pose potential risks to aquatic life and human health through the ingestion or absorption of dye-contaminated water or food. Acid orange 7 (AO7) is a synthetic azo dye used in the textile, tanning, food, pharmaceutical, paint, electronics, cosmetics, and paper and pulp industries. AO7 can have various human health implications, such as dermatitis, nausea, severe headache, respiratory tract irritation, and bone marrow depletion, due to its high toxicity, mutagenicity, and carcinogenicity. Efforts to regulate and mitigate dye pollution (AO7) are crucial for environmental sust... [more]
41. LAPSE:2024.1965
Electrochemical Polishing Method for Titanium Alloys with a Microgroove Structure
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: electrochemical polishing, electrolyte flow rate, removal behavior, TI–6Al–4V, zinc chloride
TI−6AL−4V alloys are widely used in various fields owing to their excellent corrosion resistance, high-temperature resistance, and low-temperature toughness. Herein, a microgroove fixture was used to simulate the microgrooves in a titanium alloy with different aspect ratios to study the influence of the electrolyte flow rate on the polishing effect. The optimization of the electrochemical polishing parameters was conducted using experiments and simulations. The effects of process parameters, such as the concentration of sodium chloride (NaCl) and zinc chloride (ZnCl2), polishing time, and processing voltage, on the quality of the post-polished surface were studied. Experiments were conducted on microgrooves with different aspect ratios under the optimized polishing process parameters. Changes in the surface elements of the microgrooves after polishing were detected. The experimental results indicated that the optimal electrochemical polishing solution flow rate, NaCl concentration, ZnC... [more]
42. LAPSE:2024.1964
Study on the Evolution of Physicochemical Properties of Carbon Black at Different Regeneration Stages of Diesel Particulate Filters Regenerated by Non-Thermal Plasma
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: carbon black, diesel particulate filter, non-thermal plasma, oxidation, regeneration
As a new type of aftertreatment technology, non-thermal plasma (NTP) can effectively decompose the particulate matter (PM) deposited in diesel particulate filters (DPFs). In this paper, a regeneration test of a DPF loaded with carbon black was carried out using an NTP injection system, and the changes of oxidative activity, elemental content, and occurrence state, microstructure and graphitization degree of carbon black were analyzed to reveal the evolution of the physicochemical properties of carbon black at different regeneration stages of the DPF regenerated by NTP. As the regeneration stage of the DPF advanced, Ti, Tmax, and Te of the carbon black at the bottom of the DPF decreased, which were higher than those at the regeneration interface. After the NTP reaction, the proportion of C element decreased to less than 80%, while the proportion of O element increased to more than 20%; C-O was converted to C=O and the relative content of C=O increased. The average microcrystalline lengt... [more]
43. LAPSE:2024.1963
Polyhydroxyalkanoate Production by Actinobacterial Isolates in Lignocellulosic Hydrolysate
August 28, 2024 (v1)
Subject: Materials
Keywords: bioplastic, biopolymer, Gordonia, Micromonospora, polyhydroxyalkanoate synthase
Polyhydroxyalkanoate (PHA) polymers are environmentally friendly alternatives to conventional plastics. In support of a circular bioeconomy, they can be produced by growing microbial strains in waste materials, including lignocellulosic biomass, such as Canola fines (straw). In this study, PHA and polyhydroxybutyrate (PHB) production by a selection of seven wild-type actinobacterial strains, including three strains of Gordonia species, were assessed. When grown in defined media and hydrolysates of Canola fines, the highest amounts of PHB were produced by Nocardia gamkensis CZH20T (0.0476 mg/mL) and Gordonia lacunae BS2T (0.0479 mg/mL), respectively. Six strains exhibited a substrate preference for cellobiose over glucose, xylose, and arabinose in the hydrolysates. Analysis of Fourier transform infrared spectra indicated that the strains produced co-polymers of short- and medium-chain-length PHAs. None of the core phaABC genes were found on defined operons in the genomes of the top PHB-... [more]
44. LAPSE:2024.1962
Recent Advances in Biochar: Synthesis Techniques, Properties, Applications, and Hydrogen Production
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: biochar, Biomass, biomass selection, hydrogen production, pyrolysis
The field of material sciences has evolved vastly in the last two decades, largely due to the discovery of carbon nanomaterials such as graphene and its derivatives. Although they offer positive characteristics, the cost of production and material processing of these carbon nanomaterials has limited their application. However, scientists have started searching for cheaper and more environmentally friendly alternatives. Biochar, a carbonaceous material derived from biowaste, is the most viable alternative, as it offers characteristics on par with traditional carbon nanomaterials. This review will discuss the production of biochar from biomass, methods of production, the effects various conditions have on the production of biochar, biomass selection, current biochar applications, and the potential biochar has to produce hydrogen as an energy carrier.
45. LAPSE:2024.1961
Organic Waste for Bioelectricity Generation in Microbial Fuel Cells: Effects of Feed Physicochemical Characteristics
August 28, 2024 (v1)
Subject: Biosystems
Keywords: bioelectricity generation, COD removal, feed physicochemical characteristics, microbial fuel cell, organic wastes
Food waste (FW), piggery waste (PW), and activated sludge (AS) were investigated as potential organic feeds for bioelectricity generation in laboratory-scale microbial fuel cells (MFCs). The MFCs fed by FW gained the highest maximum power density at 7.25 W/m3, followed by those fed by PW at 3.86 W/m3 and AS at 1.54 W/m3. The tCOD removal in the FW-, PW-, and AS-MFCs reached 76.9%, 63.9%, and 55.22%, respectively, within a 30-day retention time. Food waste, which resulted in the highest power density and tCOD removal, was selected for a series of following tests to investigate the effects of some physicochemical properties of organic feed on the performance of MFCs. The effect of feed particle size was tested with three controlled size ranges (i.e., 3, 1, and <1 mm) in MFCs. A smaller feed particle size provided a higher power density of 7.25 W/m3 and a tCOD removal of 76.9% compared to the MFCs fed with organic waste with a larger particle size. An increment in feed moisture from 70... [more]
46. LAPSE:2024.1960
Target Tracking Two Degrees of Freedom State Feedback Control for Continuous Flow Microfluidic Chips Temperature Controller
August 28, 2024 (v1)
Subject: Process Control
Keywords: 2DOF, MIMO, SFC, temperature control
Microfluidic chips represent a cutting-edge technology for manipulating fluids within micrometer-scale spaces and are gradually becoming a new favorite platform in life science research. Precise and fast zonal temperature control is essential for accelerating biological experiments. However, current multi-channel temperature controllers typically rely on multiple channel sets to achieve single set-point control, which results in discrepancies between the fluid temperature distribution and sensor temperature due to the distributed temperature field in the fluid channel. To estimate the actual temperature and implement gradient temperature control, this paper introduces an extension of the target tracking (TT) two degrees of freedom (2DOF) state feedback control (SFC) method, followed by a presentation of simulation and experimental results. Through comparisons with an enhanced PID system in both simulation and experimentation, the paper demonstrates an 8.96% reduction in the maximum tem... [more]
47. LAPSE:2024.1959
Kinetics of Vegetable Oils (Rice Bran, Sunflower Seed, and Soybean) Extracted by Pressurized Liquid Extraction in Intermittent Process
August 28, 2024 (v1)
Subject: Environment
Keywords: Ethanol, kinetic study, pressurized liquid extraction, rice bran, rolled soybean, sunflower
The research focuses on optimizing vegetable oil production processes for human consumption, emphasizing green and efficient extraction methods using renewable solvents with minimal toxic residues. Pressurized liquid extraction (PLE), especially with ethanol, is studied for its efficiency and low solvent usage in intermittent processes. By evaluating extraction parameters and kinetics, the study aims to determine optimal conditions for higher extraction rates and yields, providing insights into production costs and other factors. Specifically, the research examines the behavior of extraction kinetics for vegetable oils like rice bran, sunflower seeds, and rolled soybeans. It also seeks to determine mass diffusivity in semi-continuous processes and to model PLE in intermittent processes using Fick’s Law and Mathematica Wolfram Software v11.2. The effective diffusivity (Deff) for rice bran oil in pressurized ethanol varied between 13.09 and 15.70 × 10−12 m2/s, and the Deff value of sunfl... [more]
48. LAPSE:2024.1958
An Adaptive Discrete Integral Terminal Sliding Mode Control Method for a Two-Joint Manipulator
August 28, 2024 (v1)
Subject: Process Control
Keywords: adaptive control, discrete integral terminal sliding mode control, disturbance delay estimation, manipulator, trajectory tracking
In response to the trajectory tracking control problem of manipulators under measurement disturbances, a novel multi-input multi-output discrete integral terminal sliding mode control scheme is proposed. Initially, this scheme establishes a dynamic model of a two-joint manipulator based on the Lagrangian dynamics analysis method. Subsequently, a discrete integral terminal sliding mode control law based on the dynamic model of the two joints is designed, incorporating delayed estimation of unknown disturbances and discretization errors in the manipulator system. To enhance the trajectory tracking accuracy of the control scheme and suppress the impact of sliding mode chattering on the manipulator system, an adaptive switching term is introduced into the discrete integral terminal sliding mode control law. The paper derives an adaptive discrete integral terminal sliding mode control scheme and provides stability proof for the proposed approach. Simulation experiments are conducted to comp... [more]
49. LAPSE:2024.1957
Approach to Chemical Process Transition Control via Regulatory Controllers with the Case of a Throughput Fluctuating Ethylene Column
August 28, 2024 (v1)
Subject: Energy Systems
Keywords: chemical process transition, dynamic optimization, process control, process systems engineering, set-point optimization
For chemical processes, dynamic optimization is employed for process transition. On the basis of the multilayer control structure, the employment of dynamic optimization is affected by the regulatory control system. To avoid the adjustment of the regulatory control system, set-point optimization is proposed. For comparison, two types of optimization models, namely direct optimization and set-point optimization, are formulated. The superiority of set-point optimization is rigorously proven. By simulating the commercial process of a throughput-fluctuating ethylene column, the integrated absolute error and maximum deviation of product quality are reduced by more than 150% with set-point optimization. The results indicate that the approach to process transition via regulatory controllers not only avoids the insecurity caused by the switching of set-point controllers but also improves the optimization performance. In conclusion, the proposed optimization structure, namely set-point optimiza... [more]
50. LAPSE:2024.1956
Recent Advancements in Photo-Bioreactors for Microalgae Cultivation: A Brief Overview
August 28, 2024 (v1)
Subject: Process Design
Keywords: Biomass, bubble column, closed systems, cultivation, flat-panel, membrane, microalgae, PBR, photobioreactors, tubular
Inspired by the vast potential of microalgae in the bioeconomy and the numerous applications and benefits associated with their cultivation, a multitude of pilot- and industrial-scale microalgae production systems have been developed in recent years. Both open and closed cultivation systems have been successfully utilized, with closed photo-bioreactors (PBRs) emerging as the most versatile option for various applications and products, enabling the implementation of advanced optimization strategies. Therefore, this short review provides a comprehensive overview of the different PBR configurations and their recent applications, primarily in large-scale but also in pilot- and laboratory-scale microalgae cultivation. A detailed discussion of the advantages, limitations, specific applications and recent advancements of each type of PBR is presented to aid researchers, engineers and industry stakeholders in selecting the most suitable PBR design for their specific goals and constraints. More... [more]