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Records with Type: Published Article
11320. LAPSE:2023.28135
Are Neural Networks the Right Tool for Process Modeling and Control of Batch and Batch-like Processes?
April 11, 2023 (v1)
Subject: System Identification
Keywords: data-driven model identification, neural networks, subspace identification
The prevalence of batch and batch-like operations, in conjunction with the continued resurgence of artificial intelligence techniques for clustering and classification applications, has increasingly motivated the exploration of the applicability of deep learning for modeling and feedback control of batch and batch-like processes. To this end, the present study seeks to evaluate the viability of artificial intelligence in general, and neural networks in particular, toward process modeling and control via a case study. Nonlinear autoregressive with exogeneous input (NARX) networks are evaluated in comparison with subspace models within the framework of model-based control. A batch polymethyl methacrylate (PMMA) polymerization process is chosen as a simulation test-bed. Subspace-based state-space models and NARX networks identified for the process are first compared for their predictive power. The identified models are then implemented in model predictive control (MPC) to compare the cont... [more]
11321. LAPSE:2023.28134
Characterization of Sargassum spp. from the Mexican Caribbean and Its Valorization through Fermentation Process
April 11, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: antioxidants, Aspergillus niger, liquid fermentation, Mexican Caribbean, Sargassum spp.
is a brown macroalga that has become a general environmental problem in the Mexican Caribbean. Despite the negative effects on the beaches, the algae contain compounds of biotechnological and agronomic interest. The possibility of using sargassum as a substrate under liquid media fermentation (LMF) processes will allow the obtention of bioactive compounds. In this research, five species of Sargassum from the Puerto Morelos region were collected from the beach. The samples were divided into natural Sargassum and washed Sargassum, and the total phenolic compounds (TPC), flavonoids (F), and antioxidant capacity (AOxC) were determined. Once the material was characterized, it was fermented in the LMF process using the Aspergillus niger strain, where the obtained extracts were analyzed. Three holopelagic and one benthic species were identified. The proximal analysis of the seaweed in natural and washed conditions shows adequate carbon−nitrogen ratio values for use as a substrate for microbia... [more]
11322. LAPSE:2023.28133
Onion (Allium cepa L.) Yield and Quality Depending on Biostimulants and Nitrogen Fertilization—A Chemometric Perspective
April 11, 2023 (v1)
Subject: Biosystems
Keywords: bioactive compounds, chemometric, classification, onion
The influence of biostimulants (B) and nitrogen (N) fertilization on the yield and quality of onions were investigated. Experiments in the field with directly seeded (DS) onions and those from sets (FS) were carried out in 2021 in the Autonomous Province of Vojvodina (Serbia). HumiBlack® (B1), Tifi® (B2), and Agasi® (B3) were used as B, and there was a control without B. Four N doses were used: 64, 100, 150 (standard dose), and 200 kg N/ha. The highest yields of DS onions (63.9 t/ha) and FS onions (52, 1 t/ha) were measured on treatment B2 × 150 kg N/ha. The highest total sugar content (80.6 g/100 g DM) was measured in FS onions under treatment B2 × 100 kg N/ha. Total nitrogen and protein content were the highest in DS onions treated with B2 × 200 kg N/ha, where total nitrogen was 2.3 g/100 g DM and protein content was 14.5 g/100 g DM. Depending on B and N, titratable acidity ranged from 1.7 to 3.6 g/100 g DM. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) w... [more]
11323. LAPSE:2023.28132
Analysis of Bottomhole Rock Stress in Deep-Well Drilling Considering Thermal-Hydro-Mechanical Coupling
April 11, 2023 (v1)
Subject: Optimization
Keywords: bottomhole stress field, deep-well drilling, finite element analysis, rock breakage mechanism, thermal-hydro-mechanical coupling
Drilling is a key step in the exploitation of deep oil and gas resources. In order to clarify the stress state of the rocks and the mechanism of rock breakage in deep-well drilling, a thermal-hydro-mechanical coupling model for deep-well drilling was established, and the effects of drilling on the temperature, pressure, and stress in the formation were studied. Furthermore, the effects of the formation parameters and wellbore parameters on the bottomhole stress were analyzed. The results revealed that after the formation was drilled, the temperatures in different horizontal in situ stress directions were not significantly different, but the difference in the pore pressure between the maximum and minimum horizontal stress directions was large. The average effective stress at the bottom of the hole was the smallest, and in some areas, it was tensile stress. For deep-well drilling, as the formation pressure increased, the in situ stress increased, and the permeability decreased, leading t... [more]
11324. LAPSE:2023.28131
Peak Load Shifting Control for a Rural Home Hotel Cluster Based on Power Load Characteristic Analysis
April 11, 2023 (v1)
Subject: Process Control
Keywords: cluster control strategy, demand side management (DSM), load data analysis, PCM storage, rural home hotels
The large-scale rural home hotel clusters have brought huge pressure to the rural power grid. However, the load of rural home hotels not only has the inherent characteristics of rural residential buildings but is also greatly impacted by the occupancy rate, which is very different from conventional buildings. Therefore, the existing peak shifting strategies are difficult to apply to rural home hotels. In view of the above problems, this study took a typical visitor village in Zhejiang Province as the research object, which had more than 470 rural home hotels. First, through a basic information survey and power load data collection, the characteristics of its power load for heating, cooling and transition months were studied, and a “No Visitors Day” model was proposed, which was split to obtain the seasonal load curve for air conditioning. Then, combined with the characteristics of the air conditioning power load and the natural conditions of the rural house, a cluster control peak-load... [more]
11325. LAPSE:2023.28130
Design and Evaluation of Regenerated Landscapes of Factory Sites Based on Evaluation Factors
April 11, 2023 (v1)
Subject: Process Design
Keywords: evaluation factors, indicator system, Kailuan system of industrial heritage, regenerated landscape
Research in the field of industrial heritage regeneration suffers from high subjectivity and low reliability in design and evaluation. The study takes seven regeneration projects of the Kailuan family of industrial heritage as examples, designs four optimisation and improvement strategies and constructs an evaluation system containing four intermediate layers and 23 indicator layers based on the evaluation factor method to realise the evaluation of design solutions. The average evaluation value of the four intermediate layers was approximately 0.65, and the average evaluation value of the 23 evaluation indicators was approximately 0.68. The evaluation values of the four intermediate layers for the seven Kailuan projects showed that the evaluation of the park and the evaluation of the participants’ perceptions were roughly higher than the standard values, while the evaluation of the buildings and the evaluation of the environmental image had lower evaluation values. The correlations bet... [more]
11326. LAPSE:2023.28129
Dynamic Parameter Simulations for a Novel Small-Scale Power-to-Ammonia Concept
April 11, 2023 (v1)
Subject: Process Design
Keywords: Aspen Plus Dynamics®, dynamic process simulation, novel process design, power-to-ammonia
Ammonia is a promising carbon-free energy vector, hydrogen carrier, and efficient means for long-time hydrogen storage. Power-to-ammonia-to-power concepts, powered exclusively by electricity from renewable sources, will leave the carbon economy behind and enter a truly renewable era. However, the fluctuating nature of renewables requires a good dynamic behavior of such concepts. Employing the software Aspen Plus Dynamics®, this paper investigates the dynamic behavior of a novel containerized power-to-ammonia solution to be tested at the University of Genova in 2023. Implementing a novel kinetic reaction model, the impacts of several deviations from the optimal values of the cycle parameters are investigated. The simulations provide practical guidance on how to best and safely operate the cycle. A total of ten scenarios were simulated, of which six are acceptable, two are desirable, and two should be avoided. However, all scenarios can be safely controlled by the control infrastructure.
11327. LAPSE:2023.28128
Classification of Tumor in Brain MR Images Using Deep Convolutional Neural Network and Global Average Pooling
April 11, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: deep learning, global average pooling, magnetic resonance imaging, medical imaging, transfer learning, tumor detection
Brain tumors can cause serious health complications and lead to death if not detected accurately. Therefore, early-stage detection of brain tumors and accurate classification of types of brain tumors play a major role in diagnosis. Recently, deep convolutional neural network (DCNN) based approaches using brain magnetic resonance imaging (MRI) images have shown excellent performance in detection and classification tasks. However, the accuracy of DCNN architectures depends on the training of data samples since it requires more precise data for better output. Thus, we propose a transfer learning-based DCNN framework to classify brain tumors for example meningioma tumors, glioma tumors, and pituitary tumors. We use a pre-trained DCNN architecture VGGNet which is previously trained on huge datasets and used to transfer its learning parameters to the target dataset. Also, we employ transfer learning aspects such as fine-tune the convolutional network and freeze the layers of the convolutiona... [more]
11328. LAPSE:2023.28127
Data-Driven Prediction of Li-Ion Battery Degradation Using Predicted Features
April 11, 2023 (v1)
Subject: Energy Systems
Keywords: end-of-life, feature engineering, Gaussian process mode, Li-ion battery degradation, multi-step lookahead, voltage and temperature curves
For their emergent application in electric vehicles, the development of fast and accurate algorithms to monitor the health status of batteries and aid decision-making in relation to maintenance and replacement is now of paramount importance. Data-driven approaches are preferred due to the difficulties associated with defining valid models for system and parameter identification. In recent years, the use of features to enhance data-driven methods has become commonplace. Unless the data sets are from multiple batteries, however, such approaches cannot be used to predict more than one cycle ahead because the features are unavailable for future cycles, in the absence of different embedding strategies. In this paper, we propose a novel approach in which features are predicted for future cycles, enabling predictions of the state of health for an arbitrary number of cycles ahead, and, therefore, predictions for the end-of-life. This is achieved by using a data-driven approach to predict volta... [more]
11329. LAPSE:2023.28126
Characterization on Structure and Fractal of Shale Nanopore: A Case Study of Fengcheng Formation in Hashan Area, Junggar Basin, China
April 11, 2023 (v1)
Subject: Materials
Keywords: fractal dimension, Halaalate mountain, low-temperature nitrogen adsorption, pore structure, shale oil
The Lower Permian Fengcheng Formation in Halaalate Mountain in the Junggar Basin has enormous potential for shale oil, while few investigations on quantifying pore structure heterogeneity have been conducted. Thus, total organic carbon (TOC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and low-temperature N2 adsorption tests were conducted on the shales collected from the HSX1 well in the Hashan region to disclose the microscopic pore structure and its heterogeneity. Results show that the selected shales mainly consist of quartz, plagioclase, calcite, and clay minerals. The primary pore types are intergranular pores in quartz and carbonate and intragranular pores in clays, while organic matter (OM) pores are rare. Typical types of H2 and mixed H2-H3 were observed. Type H3 shale pore size distributions (PSD) are unimodal, with a peak at about 70 nm, while Type H2-H3 shales are bimodal, with peaks at about 70 nm and 3 nm, respectively. Type H3 shales have lower D2 than T... [more]
11330. LAPSE:2023.28125
Estimation of Chlorine Concentration in Water Distribution Systems Based on a Genetic Algorithm
April 11, 2023 (v1)
Subject: Optimization
Keywords: chlorine, Genetic Algorithm, hydraulic network, model calibration, Optimization, water quality
This paper proposes a methodology based on a genetic algorithms (GA) to calibrate the parameters of a chlorine decay model in a water distribution system (WDS). The proposed methodology first contemplates that a GA is implemented using historical measurements of chlorine concentration at some sensed nodes to calibrate the unknown values corresponding to both the bulk and wall reaction coefficients. Once both parameters are estimated, the optimal-fit chlorine decay model is used to predict the decay of chlorine concentration in the water at each node for any concentration input at the pumping station. Then, a second GA-based algorithm is implemented to obtain the minimal chlorine concentration needed at the input to ensure that every node in the system meets the official normativity requirements for free chlorine in a WDS. The proposed methodology performed satisfactorily for a WDS simulated in EPANET with a GA implemented in MATLAB, both for the estimation of the reaction coefficients... [more]
11331. LAPSE:2023.28124
Finite−Discrete Element Method Prediction of Advanced Fractures in Extra-Thick Coal Seams Based on a Constitutive Model of Rock Deformation−Fragmentation Failure Process
April 11, 2023 (v1)
Subject: Materials
Keywords: constitutive model, extra-thick coal seam, finite–discrete element method, pre-grouting technology, roof fall disaster
Roof fall is a frequent and destructive disaster in the working face of extra-thick coal seams. The important technology for disaster elimination is roof grouting, and the key to its success is to accurately predict the distance of the advanced fractures based on a reasonable rock constitutive relationship. In this paper, the constitutive relationship reflecting the progressive failure process of rock was established, including the elastic−plastic constitutive relation of intact rock, the fracture constitutive relation of non-penetrating fracture, and the shear friction constitutive relation of penetrating fracture. On this basis, the finite−discrete element method (FDEM) numerical calculation method was developed. Taking Yushupo Coal mine with a 16-m-thick coal seam as an example, the numerical results showed that the fractures in the roof appear 15~35 m ahead of the working face, and the maximum value of advance bearing pressure is between 16 and 30 MPa. Meanwhile the laboratory test... [more]
11332. LAPSE:2023.28123
Non-Toxic and Flexible Radiation-Shielding Composites Based on Natural Rubber Containing Elemental W Fillers for Efficient Shielding against X/γ-rays
April 11, 2023 (v1)
Subject: Materials
Keywords: elemental W fillers, mechanical properties, radiation-shielding composites, shielding properties, X/γ-rays
Conventional radiation-shielding composites usually contain lead, which results in high toxicity and poor portability. Tungsten (W) is an ideal radiation-shielding element that can replace lead due to its high atomic number and non-toxicity. In this work, radiation-shielding composites were prepared using natural rubber (NR) as a matrix and three different particle size powders, namely W, WO3 and WC, as fillers. The results show that, for X-rays, the linear attenuation coefficient of radiation-shielding composites based on natural rubber containing WC with a particle size of 50 μm (50 WC/NR) is 27.005 cm−1 at an X-ray tube voltage of 40 kV, which is more than 14 times the linear attenuation coefficient of NR. For γ-rays, a linear attenuation coefficient of 50 WC/NR achieves 8.320 cm−1 at 81 keV, which is over 55 times the linear attenuation coefficient of NR. In addition, 50 WC/NR had the highest elongation at break at 548.989% and had the lowest hardness at 62 HA. In summary, 50 WC/NR... [more]
11333. LAPSE:2023.28122
Development of Combined Methods Using Non-Destructive Test Methods to Determine the In-Place Strength of High-Strength Concretes
April 11, 2023 (v1)
Subject: Modelling and Simulations
Keywords: combined methods, compressive strength, highstrength concrete, non-destructive test methods, response surface method
This study aims to develop combined methods with dual and triple use of different non-destructive test (NDT) methods and to examine the effectiveness of these methods. For this purpose, nine different high-strength concrete series were produced, and destructive and NDT methods were applied to these samples on the 3rd and 90th days. Surface hardness, ultrasonic pulse velocity, and penetration resistance were considered from NDT methods. Analyses were made on the response surface method using the NDT measurements and compressive strength values obtained, and four different mathematical models were developed. Models 1, 2, and 3 were designed with dual use of NDT methods, and model 4 was designed with triple use. The absolute relative deviation values for all the developed models’ early and final-age strengths were below 10%. It is of great importance to determine concrete quality with high accuracy and practicality, especially in places like Elazig, where there are thousands of newly cons... [more]
11334. LAPSE:2023.28121
Application of PLC-Based Spectrophotometric System Nitrogen Protection Device to Automated Direct Measurement of Target Substances in Zinc Hydrometallurgy
April 11, 2023 (v1)
Subject: Process Control
Keywords: automated control, nitrogen protection device, PLC, spectrophotometric system, zinc hydrometallurgy
Due to the fast material reaction in zinc hydrometallurgy, the traditional national standard photometric method cannot capture the characteristic information of target substances in real time. Herein, a nitrogen protection device is built based on ultraviolet spectrophotometry, supplemented by a programmable logic controller (PLC), to form an automatic control system for the direct detection of target substances (SO42−, Pb2+ and S2−) in zinc hydrometallurgy. The baseline straightness comparison results show that the nitrogen atmosphere can effectively improve the stability of the instrument. Furthermore, the detection sensitivity of SO42−, Pb2+ and S2− under the nitrogen atmosphere is higher than that of the air atmosphere, manifesting in sensitivity increases of 16.23%, 18.05% and 17.91%, respectively. Additionally, devices based on PLC systems show advantages over manual control both in states feedback and information backtrack. Moreover, the regulation time and nitrogen consumption... [more]
11335. LAPSE:2023.28120
Performance of Biomass and Exopolysaccharide Production from the Medicinal Mushroom Ganoderma lucidum in a New Fabricated Air-L-Shaped Bioreactor (ALSB)
April 11, 2023 (v1)
Subject: Optimization
Keywords: bioprocess optimization, exopolysaccharide, Ganoderma lucidum, smart bioreactor, wall growth
Conventional stirred-tank bioreactor (STR) designs are optimised for cultures of bacteria but not fungal cultures; therefore, a new Air-L-Shaped Bioreactor (ALSB) was fabricated. The ALSB was designed to eliminate the wall growth and clumping of fungal mycelium in STRs. Ganoderma lucidum was used as a fungal model and its biomass and exopolysaccharide (EPS) production were maximised by optimising the agitation rate, glucose concentration, initial pH, and aeration via response surface methodology (RSM). The ALSB system generated 7.8 g/L of biomass (biomass optimised conditions: 110 rpm, 24 g/L glucose, pH 5.6, and 3 v/v of aeration) and 4.4 g/L of EPS (EPS optimised conditions: 90 rpm, 30 g/L glucose, pH 4, and 2.5 v/v of aeration). In combination, for both optimised conditions, biomass (7.9 g/L) and EPS (4.6 g/L) were produced at 110 rpm, 30 g/L glucose, pH 4, and 3 v/v of aeration with minimal wall growth. The data prove that the ALSB is a blueprint for efficient economical fungal cul... [more]
11336. LAPSE:2023.28119
Numerical Simulation and Field Test Research on Vibration Reduction of PDC Cutting of Pebbled Sandstone under Composite Impact Load
April 11, 2023 (v1)
Subject: Modelling and Simulations
Keywords: composite impactor, discrete element method, impact drilling, PDC cutter, pebbled sandstone
Downhole vibrations caused by rock breaking when drilling through pebbled sandstone formations negatively affect the rate of penetration (ROP) and the safety of downhole tools. Therefore, it is of great significance to study the cutting characteristics of pebbled sandstone and find a method of reducing the drilling vibrations of pebbled sandstone formations. Based on the DEM (discrete element method), a simulation model of pebbled sandstone considering the random filling of high-strength gravels was established by using the random polygon distribution method. The influence of gravel content on the strength parameters and the breaking state of the pebbled sandstone samples was analyzed. Additionally, a DEM model of PDC cutting rocks loaded by a spring−mass system was established, and the Stribeck effect of contact friction between the PDC cutter and the rock was analyzed. The periodic vibration and the stick−slip phenomenon of the cutting system during the drilling process were presente... [more]
11337. LAPSE:2023.28118
Optimization of Polyphenol Extraction with Potential Application as Natural Food Preservatives from Brazilian Amazonian Species Dalbergia monetaria and Croton cajucara
April 11, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: Amazon, Croton cajucara, Dalbergia monetaria, natural additives
Scientific interest has currently focused on natural products as a feasible approach for new food additives to replace synthetic preservatives. Thereby, the objective of this work was to optimize the polyphenol extraction from native Amazonian plant species Dalbergia monetaria L.f. and Croton cajucara Benth., and they were determined by the total content of these compounds. Accordingly, the hydroalcoholic extract’s phytocomposition was analyzed by ultra-high-performance liquid chromatography−diode array detector (UPLC-DAD) and various assays to determine the antioxidant capacity (e.g., 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, ferric reduction power, peroxidation inhibition). In addition, response surface methodology applying a central composite design was used to optimize the antioxidant compound extraction conditions. Extract phytochemical profiles identified polyphenols such as (-)-epigallocatechin gallate, rutin, and hyperoside in both species. Furthermore, D. m... [more]
11338. LAPSE:2023.28117
A Tool Condition Monitoring System Based on Low-Cost Sensors and an IoT Platform for Rapid Deployment
April 11, 2023 (v1)
Subject: Information Management
Keywords: industrial internet of things, IoT platform, logistic regression, Modelling, tool condition monitoring
Tool condition monitoring (TCM) systems are key technologies for ensuring machining efficiency. Despite the large number of TCM solutions, these systems have not been implemented in industry, especially in small- and medium-sized enterprises (SMEs), mainly because of the need for invasive sensors, time-consuming deployment solutions and a lack of straightforward, scalable solutions from the laboratory. The implementation of TCM solutions for the new era of the Industry 4.0 is encouraging practitioners to look for systems based on IoT (Internet of Things) platforms with plug and play capabilities, minimum interruption time during setup and minimal experimental tests. In this paper, we propose a TCM system based on low-cost and non-invasive sensors that are plug and play devices, an IoT platform for fast deployment and a mobile app for receiving operator feedback. The system is based on a sensing node by Arduino Uno Wi-Fi that acts as an edge-computing node to extract a similarity index... [more]
11339. LAPSE:2023.28116
Modeling of an Organic Rankine Cycle Integrated into a Double-Effect Absorption System for the Simultaneous Production of Power and Cooling
April 11, 2023 (v1)
Subject: Modelling and Simulations
Keywords: absorption cooling system, organic Rankine cycle, power production, waste heat recovery
Climate change is one of the main problems that humanity is currently facing due to carbon dioxide emissions caused by fossil fuel consumption. Organic Rankine cycles may play an important role in reducing these emissions since they can use industrial waste heat or renewable energies. This study presents the proposal and modeling of an organic Rankine cycle integrated into a double-effect absorption cooling system for the simultaneous production of power and cooling. The working fluids utilized were the ammonia−lithium nitrate mixture for the absorption system and benzene, cyclohexane, methanol, and toluene for the organic Rankine cycle. The influence of the primary operating parameters on the system performance was analyzed and discussed in terms of cooling load, turbine power, energy utilization factor, and exergy efficiency for a wide range of operating conditions. It was found that, for all cases, the cooling load was dominant over the turbine power since the minimum cooling load o... [more]
11340. LAPSE:2023.28115
Prediction of Longitudinal Superimposed “Sweet Spot” of Tight Gas Reservoir: A Case Study of Block G, Canada
April 11, 2023 (v1)
Subject: Energy Systems
Keywords: key parameters, longitudinal superimposed sweet spot, MIC, Pearson correlation coefficient, tight gas reservoir
In this paper, taking Block G in Canada as an example, combined with the data of the working area, the Pearson−MIC comprehensive evaluation method was adopted to optimize the key parameters of productivity. Based on the analytic hierarchy process, the weight of each parameter was calculated, the grade of evaluation index of the “sweet spot” was divided, the standard of the sweet spot was established, and the distribution of the superimposed sweet spot was finally depicted. The results show that lateral length, number of stages, volume of fluid, and amount of proppant are the key engineering parameters of horizontal well, and lateral length is an independent key engineering parameter. The cumulative gas production in the first two years was normalized on the lateral length to eliminate the engineering influence, and the total organic carbon (TOC) was finally determined as the key geological parameter, whereas porosity and water saturation were the secondary key parameters. The area of T... [more]
11341. LAPSE:2023.28114
Discussion on the Need for Harvested Rainwater Quality Standards Tailored to the Reuse Purpose
April 11, 2023 (v1)
Subject: Environment
Keywords: harvested rainwater quality, health and environmental risks, rainwater harvesting, rainwater use, recasted urban wastewater treatment directive, standards
Rainwater harvesting attracts rising interest in solving the new challenges associated with climate change and socio-economic development. Rainwater harvesting is addressed in various policies, but standards related to the harvested rainwater quality (HRWQ) are currently set mostly for reuse for agricultural purposes. This paper discusses the necessity for the introduction of specific legislative requirements for the HRWQ tailored to the reuse purpose, which would reduce the health and environmental risks. Based on a literature review of research outcomes regarding HRWQ parameters and existing legislation, the paper discusses the complexity of the factors influencing HRWQ and provides some thoughts for possible actions forward that could be undertaken toward the development of specific legislation. The actions include the application of a risk-based approach, the development of a database and guidance with technological solutions.
11342. LAPSE:2023.28113
Finite Amplitude Oscillatory Convection of Binary Mixture Kept in a Porous Medium
April 11, 2023 (v1)
Subject: Energy Systems
Keywords: binary mixture, finite amplitude, heatlines, Nusselt number, oscillatory convection, porous media
In the present study, the double-diffusive oscillatory convection of binary mixture, 3He−4He, in porous medium heated from below and cooled from above was investigated with stress-free boundary conditions. The Darcy model was employed in the governing system of perturbed equations. An attempt was made, for the first time, to solve these equations by using the nonlinear analysis-based truncated Fourier series. The influence of the Rayleigh number (R), the separation ratio (ψ) due to the Soret effect, the Lewis number (Le), and the porosity number (χ) on the field variables were investigated using the finite amplitudes. From the linear stability analysis, expressions for the parameters, namely, R and wavenumbers, were obtained, corresponding to the bifurcations such as pitchfork bifurcation, Hopf bifurcation, Takens−Bogdnanov bifurcation and co-dimension two bifurcation. The results reveal that the local Nusselt number (NL) increases with R. The total energy is enhanced for all increasin... [more]
11343. LAPSE:2023.28112
Operating Parameters Optimization for the Production of Liposomes Loaded with Antibodies Using a Supercritical Fluid-Assisted Process
April 11, 2023 (v1)
Subject: Optimization
Keywords: antibody-based therapy, drug delivery, liposomes, supercritical fluids
Encapsulation of antibodies represents a significant advance to protect and deliver these therapeutics in a controlled manner, increasing the stability requested to cover the temporal gap between particle production and their administration. Furthermore, using encapsulation, extracellular, cell surface, and intracellular targets can be reached. This work examines the feasibility of encapsulating mouse IgG isotype control antibodies within phosphatidylcholine-based liposomes using a supercritical fluid-based process called SuperLip (Supercritical-assisted Liposome formation). This process allows a continuous production of both nano- and micrometric liposomes with high encapsulation efficiency working under mild operative conditions. The effect of some operative parameters has been studied on liposome mean diameter, particle size distribution, and antibody entrapment efficiency, comparing these data with those collected working with liposomes obtained by the thin-layer hydration techniqu... [more]
11344. LAPSE:2023.28111
Sapo-34 Obtained from Amazonian Flint Kaolin: Influence of Impurities of “Oxidized Fe/Ti” in Synthesis and Its Application in the Removal of Cationic Dye from Water
April 11, 2023 (v1)
Subject: Process Design
Keywords: Adsorption, Amazonian kaolin, dye, SAPO-34, separation process
Non-processed kaolin (flint kaolin) from a mine located in the Capim area (Amazon region, northern Brazil), usually considered as waste, was selected as a source of silicon and aluminum in the synthesis of SAPO-34. This is a molecular sieve and cationic exchanger chosen for tests focusing on the removal of methylene blue in aqueous solutions, which is a cationic dye widely used by textile industries in Brazil. The results revealed that the SAPO-34 has been successfully synthesized with typical cubic morphology, good crystallinity (>90%), and thermal stability (~998 °C). Although the oxidized Fe/Ti impurities contained in the flint kaolin affect the degree of crystallinity of the zeolitic product, its adsorptive properties are not significantly affected, which demonstrates the excellent adsorption results (pH = 11; % removal > 90%). It proved to be an adsorbent with considerable adsorption capacity (9.83 mg·g−1). The pH test confirmed the acidic surface characteristics (pH solution 2−4;... [more]
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