Scale Experiments Research Articles

Synthesis of Bishomocubanone Derivatives via Visible‐Light‐Induced Intramolecular [2+2] Cycloaddition Reaction

AbstractIn this paper, a visible‐light‐induced intramolecular [2+2] cycloaddition has been revealed to synthesize the bishomocubanone derivatives in moderate to excellent yield under mild conditions. This method demonstrated a broad substrate scope and excellent functional‐group tolerance, affording cubane precursors and a series of bishomocubanones. Meanwhile, a hundred‐gram scale experiment of this method has been employed to synthesize cubane precursors with 98% yield.

Bioinspired nanofilament coatings for scale reduction on steel.

Scaling of steel surfaces, prevalent in various industrial applications, results in significant operational inefficiencies and maintenance costs. Inspired by the natural hydrophobicity of springtail (Collembola) skin, which employs micro- and nanostructures to repel water, we investigate the application of silicone nanofilaments (SNFs) as a coating on steel surfaces to mitigate scaling. Silicone nanofilaments, previously successful on polymers, textiles, and glass, are explored for their hydrophobic properties and stability on steel. Our study demonstrates the successful coating of stainless steel with SNFs, achieving super-hydrophobicity and resilience under high shear stress and explosion/decompression tests. Scaling experiments reveal a 75.5% reduction in calcium carbonate deposition on SNF-coated steel surfaces. This reduction is attributed to altered flow dynamics near the super-hydrophobic surface, inhibiting nucleation and growth of scale. Our findings highlight the potential of bioinspired SNF coatings to enhance the performance and longevity of steel surfaces in industrial environments.

Primary trader preferences for participating in high-value markets in Black Pepper- A choice analysis

Facilitating the integration of primary traders into modern agricultural value chains, known as high-value markets (HVMs), presents a promising avenue for improving the sustainability of black pepper value chains in Kerala. Due to increased price volatility and risk exposure in trading conditions, primary traders are hesitant to prioritize quality aspects in their procurement decisions. A Best-Worst Scaling (BWS) experiment was employed with traders in the Agro-ecological units (AEUs) 12, 14, 15, 16, 17, 19, 20 and 21 of Kerala to comprehend their preferences regarding quality attributes that could promote sustained participation in HVMs. This study incorporates a unique aspect by examining the consistency of choices between the best and worst options, providing deeper insights into traders' decision-making processes and ensuring an accurate evaluation of preferences by minimizing biases. The choice experiment utilized fractional factorial and balanced incomplete block designs. The results indicate that traders predominantly favour a flexible, incentive-based pricing model and long-term formal relationships with buyers. Conversely, traders consistently rated premium payments and certification as the least favourable market attributes. Preference variations were influenced by traders' experience, income levels and location. The results reveal that primary traders possess the least understanding of factors that may facilitate their entry into HVMs. Our findings underscore the significance of educating traders on crucial market attributes that facilitate their participation in HVMs. Further research on their willingness to adapt to the requirements of HVMs to maximize the benefits to the system.

Climate and soil conditions shape farmers’ climate change adaptation preferences

AbstractClimate change poses a significant threat to agriculture and challenges farmers’ adaptive capacity. Understanding how farmers evaluate and prioritize different climate change adaptation measures under consideration of their natural environment is crucial yet widely overlooked. This study determines the relative importance that farmers attach to different adaptation measures and explores the role of climatic and soil conditions in this context. It uses a best‐worst scaling experiment with German arable farmers in combination with geospatial climate and soil information. Findings reveal a preference for incremental adaptation measures over more transformative ones. However, preferences varied considerably with average local temperature, precipitation, and soil quality. The finding that farmers’ adaptation preferences are highly diverse and context‐specific calls for tailored policies. It is crucial for policymakers to have a thorough understanding of farmers’ adaptation preferences. Based on the results, the study discusses multiple actions that policymakers can take to incentivize farmers to favor more effective adaptation measures.

Threshold for oscillatory-flow ripple initiation on cohesive and non-cohesive mixtures of sand and mud

ABSTRACT The threshold hydraulic condition of wave ripple initiation has been essential in a wide range of disciplines, including coastal engineering and geology, but remains unclear for the case of sand-mud mixtures as substrates. Scale experiments were conducted using an oscillating-bed to study wave ripple initiation in sand-mud mixtures, considering bed material, wave period and maximum orbital velocity. Four kinds of sand-mud mixtures were employed as bed material with different muds (cohesive kaolin and non-cohesive silt) and mixing ratios. Ripple initiation in the cases with sand-mud mixtures tended to require larger orbital velocity than pure sand, indicating that mud mixed in bed material hinders ripple formation and spreading of the ripple field. The results of the threshold for pure sand and 10% kaolin mixture show that cohesive mixed sand-mud hindered ripple formation and spreading. In contrast, in the case of the non-cohesive sand-silt mixture beds, the results differed depending on the proportion of sand and silt, which implied the effect of the strength of network structure. The inhibition of ripple initiation due to mud mixing observed in the present experiments is considered to have a significant effect, particularly in environments with limited wave action duration, such as intertidal zone.

Platelet storage in small bags as a model of platelet function in full-sized containers.

Evaluation of additive solutions, storage containers, new collection and storage methods, and other potential modifications is resource intensive, resulting in diversion of platelets away from blood bank inventories and significant time to complete study recruitments. Our goal was to evaluate the feasibility of a small bag for the study of platelet storage, and, by using a standardized respirometry test, separate daily metabolic capacity from observations made in the dynamic storage environment of changing pH, fuels, and end products. Single-donor apheresis platelets collected in 100% plasma had small volumes removed to meet secondary processing requirements. Small volumes (23 ± 1.4 mL) were placed in 50-mL bags constructed of platelet storage material, stored 7 days, and assessed with a panel of in vitro assays. Platelet bioenergetics (oxygen consumption and acid production rates) were measured with a respirometer. The patterns of platelet pH decline, activation, and potency by thrombin generation were consistent with historical reports. Lactate production rates (54.1 ± 11.3 μmol/1012plt/h) were significantly correlated with pH decrease, increased activation, and thrombin generation potency by Day 7. Respirometry revealed a reduction of the glycolytic capacity and accumulating damage to the oxidative system for ATP production over storage. Small bags present a storage profile of metabolic changes and activation consistent with historical data for full bag storage. Therefore, this system has promise to provide a platform for scaling experiments of platelet storage in a manner that maximizes platelets collected in research settings and does not compromise availability for patient treatment as exercised in this study.

Reduced scale experiment and numerical simulation study on different airflow organization modes in large ship painting workshop

Mechanical ventilation is a key means to improve indoor air quality in shipbuilding industry. Appropriate airflow organization will have a perceptible impact on environmental safety, personnel health, and energy conservation. Many ship painting workshops use fully mixed ventilation, making it difficult to meet indoor pollutant standards and save energy. Therefore, it is necessary to optimal design the airflow organization in the ship painting workshop reasonably. This article introduces three new air supply strategies for ship painting workshops, namely piston flow air supply, attached jet air supply, and side air supply, and compares them with the existing mixed air supply. Three operating scenarios have been established, including isothermal conditions in spring and autumn, cooling condition in summer, and heating condition in winter. The airflow and pollutant distribution of each airflow organization are compared through scale model experiments and numerical simulations. Finally, the most suitable strategy for the workshop in each season is selected and promoted for engineering applications.

Composites Based on Natural Zeolites and Green Materials for the Immobilization of Toxic Elements in Contaminated Soils: A Review.

Soil contamination by toxic elements is a global problem, and the remediation of contaminated soils requires complex and time-consuming technology. Conventional methods of soil remediation are often inapplicable, so an intensive search is underway for innovative and environmentally friendly ways to clean up ecosystems. The use of amendments that stabilize the toxic elements in soil by reducing their mobility and bioavailability is one of the simplest and most cost-effective ways to remediate soil. This paper provides a summary of studies related to the use of composites based on natural zeolites and green materials for the immobilization of toxic elements in contaminated soils and highlights positive examples of returning land to agricultural use. The published literature on natural zeolites and their composites has shown that combinations of zeolite with biochar, chitosan and other clay minerals have beneficial synergistic effects on toxic element immobilization and soil quality. The effects of zeolite properties, different combinations, application rates, or incubation periods on toxic elements immobilization were tested in laboratory scale or field experiments, whereas the mobility of toxic elements in soil was evaluated by chemical extractions of toxic elements transferred to the plants. This review highlights the excellent potential of natural zeolites to be used as single or combined sustainable green materials to solve environmental pollution problems related to the presence of toxic elements.

The Mechanism of Formation of the Vibrational-Rotational Spectrum of the HCL Molecule

In this work, the harmonic and anharmonic vibrational frequencies of the HCl molecule have been determined by using the density functional theory method. Calculations have been performed at the B3LYP/6-311++G (3dp, 3df) levels of theory. Transitions between energy levels are analyzed in terms of wavenumber. The rotational constants of the HCl molecule, the wavenumbers corresponding to the rotational structure of the P, R, and Q branches in the spectrum, and their relative intensities at temperatures of 100, 200, and 300 K are calculated, and vibrational-rotational spectra are simulated. The vibrational-rotational spectrum of the HCl molecule is obtained in the range of 2600-3100 cm-1. It has been theoretically shown that when the distance between atomic nuclei in the HCl molecule increases compared to the steady state, the R branch in the spectrum, and when it decreases, the P branch is formed. Rotational constants and corresponding frequencies are calculated for each fundamental transition in rotational energy levels. All calculations use empirical and non-empirical methods. For H35Cl and H37Cl molecules, graphs of the number of fundamental transitions (m) in rotational energy levels and the wave number corresponding to these transitions are drawn. It is in good agreement with all scale experiment results. It is verified that the rotational constants (B) corresponding to the general degree of degeneration (2J+1)2 are similar to the values observed in the literature.

Numerical and experimental study on local scour in front of OWC-BWS under waves

In this paper, a system of an oscillating water column wave energy converter integrated with a vertical breakwater (OWC- BWS) was established, and the scour mechanism in front of OWC-BWS under wave actions was studied by laboratory scale experiments and gas-liquid-particle flow numerical simulation, respectively. The experiment investigates the comparison of scour test results between a conventional vertical breakwater and OWC-BWS. It shows that compared to a vertical breakwater without an OWC, the local scour phenomenon in front of the OWC-BWS was effectively mitigated (test results showed a 46.7% reduction in the maximum scour depth). For numerical simulation, a scour model under wave actions was established for further research on the local scour mechanism in front of the OWC-BWS. It was found that the local scour topography of an OWC-BWS is different from that of a vertical breakwater. The OWC device effectively weakens the scour in front of the OWC-BWS, which is because the flow field in front of the OWC-BWS shows frequent generation and shedding of vortexes. In addition, as a crucial part of the OWC-BWS, the effect of PTO was also studied, which found that the maximum equilibrium scour depth was significantly influenced under different PTO.

Real scale experiments on the wave-induced burial and mobilization of Unexploded Ordnance on the seafloor

As a result of armed conflicts, huge amounts of Unexploded Ordnance devices (UXO) and Discarded Munition Material (DMM) are expected to be located on the seafloor, especially in coastal regions. During Offshore Construction, strategical site monitoring and systematic remediation activities, the behavior of such objects in waves and currents is of huge interest as potential mobilization of objects after a survey or clearance activity could change the situational picture again. From findings and reports it often is assumed that UXO and DMM tend to migrate over the seafloor for long distances. Here, anthropogenic effects like fishing or dredging activities are underestimated. More scientific approaches clearly show that mobilization and migration of UXO over long distances does not occur. However, theoretical analysis remain theories until they are proven by experiments. For this reason, three large representative objects were investigated under real scale wave conditions in the Delta Flume of Deltares. The objects represent real scale models of UXO found in the North Sea as well as academically shaped objects. All objects as well as the Flume Tank were intensively instrumented to measure the full environmental conditions as well as the behavior of the objects. The sediment represents typical sand as found in the North Sea and the seabed morphology and soil conditions were closely monitored during the experiments. The experiments support the theoretical models that predict burial but no mobilization also under extreme wave conditions.

The Influence of Thermal Management Concepts on the Battery Behavior - Insights from a New Coupled Numerical Modelling Approach on the Battery Module Scale and Corresponding Experiments

Battery electric vehicles (BEVs) are the future mainstream drivetrain solution for the individual mobility sector. However, the fast charging capability of BEVs, which is seen as a key enabler for a broad customer acceptance and a convenient e-mobility is a remaining challenge in the development of battery systems. During fast charging, increased heat losses occur in the battery cells and the electrical connectors of a battery module. The battery thermal management then plays a crucial role to keep the battery temperature in the recommended range and to avoid accelerated degradation of the cells. Most of the conventional battery thermal management concepts in today’s BEVs are not efficient in managing the increased heat losses which leads to currently limited fast charging rates. Therefore, new thermal management solutions are being discussed and developed. A promising approach is the direct liquid cooling of batteries, also known as immersion cooling. With immersion cooling, the cells, cell tabs and electrical connectors are in contact with a dielectric fluid. Immersion cooling has the potential to increase the temperature homogeneity within and between the cells and to decrease or even prevent subsequent cell degradation.For the development of efficient thermal management systems for future BEVs and to use the full potential of concepts like immersion cooling, the influence of the thermal management on the battery cells must be understood and evaluated in detail. Considering that, a deep understanding of the interacting electrical, electrochemical, thermal and fluid dynamic phenomena occurring inside a battery module is required. Therefore, in this contribution, numerical simulations and corresponding experiments with battery modules in application-related setups are combined to study the effects of the thermal management on the battery behavior. The two fundamentally different concepts of immersion cooling and state-of-the-art bottom cooling are investigated as well as variations of each of those concepts. In the immersion cooled module, particular attention is paid to the fluid flow distribution and the effect different flow concepts on the thermal and electrochemical conditions in the cell.The numerical studies are based on a new coupled modelling approach (Fig. 1). Detailed thermal models of the 65 Ah automotive NMC/Si-Gr pouch cells are set up in a 3D CFD environment based on the analysis of the disassembly of the cell and the measurements of its thermophysical properties. Then, networks of electrochemical models of the cell are electrically and thermally coupled to the 3D models and the module components. This holistic approach allows for the investigation of e.g., the interaction of the cooling fluid flow with the current and temperature distribution and its effect on the local electrochemical cell behavior like the anode potential during fast charging.The corresponding experimental battery modules in a 3s2p configuration (Fig. 2) are explicitly designed and built for the validation of the numerical models. The cells and module components are equipped with extensive temperature measurements to capture thermal gradients within and between the cells. The modules are then installed and operated in separate climate chambers and connected to individual cooling circuits (Fig. 3) to ensure defined and equal boundary conditions as basis for the comparison of concepts and concept variations.The performance differences in various operating points including fast charging are demonstrated and analyzed. Furthermore, the variation of boundary conditions e.g., the volume flow rate or the fluid temperature allows for the analysis of relevant differences in the cooling concepts’ operating principles.The results from simulation and experiment illustrate the weak spots of the conventional concepts that are used in today’s BEVs. Furthermore, the numerical models reveal the critical local conditions inside the cells that are provoked by high loads in combination with inefficient thermal management concepts. Furthermore, the results show the benefits of immersion cooling over conventional concepts and its potential to increase the lifetime of battery systems by steering the battery temperature and temperature homogeneity with suitable fluid flow conditions. At the same time, the fast charging capability of BEVs can be increased significantly with immersion cooling.The good agreement of numerical and experimental results (Fig. 4) show that the presented modelling approach can be used as a tool for the design and the optimization of thermal management concepts. The application-related setup in this study ensures transferability of the findings from experiment and simulation to automotive applications and will help researchers and developers from industry and academia towards developing better thermal management solutions for BEVs. Figure 1

ITER-relevant 600 s steady-state extraction of negative hydrogen ions at the test facility ELISE

Abstract The neutral beam heating system for the future international fusion experiment ITER will be based on RF driven ion sources delivering a large (≈1×2 m2) and homogeneous negative hydrogen or deuterium ion beam of several ten Amperes over up to several hundred seconds. The size scaling experiment ELISE (Extraction from a Large Ion Source Experiment) is an integral part of the R&D road-map towards the ITER neutral beam heating system. Recently, 90 % of the ITER target for the extracted current density was achieved in hydrogen for 600 s, increasing the pulse length over that such current densities are possible by a factor of more than ten. For ten second beam pulses the ITER target current density was achieved. These breakthrough results are made possible by a steady-state capable HV power supply together with an improved version of internal potential rods and a modified topology of the magnetic filter field.

Building surface materials as potential sources of biocides: Insights from laboratory leaching investigations of different material types

Biocides are incorporated into building surface materials to protect them against algae and fungi growth. When such treated surfaces are exposed to precipitation, they may release these biocides, contaminating receiving water bodies. To regulate the use of biocidal products in line with the European Biocidal Products Regulation it is crucial to identify the precise origin of this type of pollutant. In this study, the leaching of a wide range of biocides and chemical elements from 15 materials was investigated through a laboratory scale experiment. The experimental setup was based on the standard method, SIS-CEN/TS 16637-2:2015. The materials tested included bitumen roofing felt and shingles, impregnated wood, as well as paints intended for concrete, wood, and metal surfaces. Each material was tested in duplicates. All materials were tested at a liquid volume to surface area ratio (L/A) of 22.5 L/m2. Sampling was carried out at three intervals: 6 h, 18 h, and 5 days with the leachant being renewed after each leaching step. The results were that diuron was the most commonly detected biocide from the materials tested. The largest number of biocides, including diuron and its degradation products 1-(3.4-dichlorophenyl) urea (DCPU) and diuron desdimethyl (DCPMU), terbutryn, carbendazim and monuron, were detected in the wood paints. Diuron was detected in all three types of wood paint with a mean areal release ratio of 64.6, 25800, and 5710 μg/m2 for the respective paints. Copper was detected in all leachates from impregnated wood, with mean concentrations of 687, 648, 1450, and 279 μg/L from the four tested wood types, respectively. Some of the biocides released were not reported on the data sheets of the tested materials, indicating a need to investigate broader than only based on the information provided by the manufacturers. Future use of biocides in building surface materials may change due to regulations, phase outs and introduction of new biocides, indicating that source identifications is a continuing effort.

Mesopredator release moderates trophic control of plant biomass in a Georgia salt marsh.

Predators regulate communities through top-down control in many ecosystems. Because most studies of top-down control last less than a year and focus on only a subset of the community, they may miss predator effects that manifest at longer timescales or across whole food webs. In southeastern US salt marshes, short-term and small-scale experiments indicate that nektonic predators (e.g., blue crab, fish, terrapins) facilitate the foundational grass, Spartina alterniflora, by consuming herbivorous snails and crabs. To test both how nekton affect marsh processes when the entire animal community is present, and how prior results scale over time, we conducted a 3-year nekton exclusion experiment in a Georgia salt marsh using replicated 19.6 m2 plots. Our nekton exclusions increased densities of plant-grazing snails and juvenile deposit-feeding fiddler crab and, in Year 2, reduced predation on tethered juvenile snails, indicating that nektonic predators control these key macroinvertebrates. However, in Year 3, densities of mesopredatory benthic mud crabs increased threefold in nekton exclusions, erasing the tethered snails' predation refuge. Nekton exclusion had no effect on Spartina biomass, likely because the observed mesopredator release suppressed grazing snail densities and elevated densities of fiddler crabs, whose burrowing alleviates soil stresses. Structural equation modeling supported the hypotheses that nektonic predators and mesopredators control invertebrate communities, with nektonic predators having stronger total effects on Spartina than mud crabs by controlling densities of species that both suppress (grazers) and facilitate (fiddler crabs) plant growth. These findings highlight that salt marshes can be resilient to multiyear reductions in nektonic predators if mesopredators are present and that multiple pathways of trophic control manifest in different ways over time to mediate community dynamics. These results highlight that larger scale and longer-term experiments can illuminate community dynamics not previously understood, even in well-studied ecosystems such as salt marshes.

Development of an efficient biocatalytic three-component reaction for synthesizing pyrrole derivatives

Multi-component reactions (MCRs) enable the development of efficient and atom-economic methods for synthesizing pyrrole derivatives. However, the current MCRs methods for synthesizing pyrrole derivatives in the enzymatic process have been unexploited. Herein, we developed a one-pot three-component enzymatic promiscuous catalytic system with green, efficient, and atom-economic to construct pyrrole derivatives. In this system, amines and 1,3-dicarbonyl compounds formed enamines with subsequent Michael addition with nitroolefins catalyzed by trypsin. A series of pyrrole derivatives were successfully obtained with moderate to good yield (up to 92 %). In addition, molecular simulations were conducted to gain insight into the source of differing tolerance of aromatic amides and fatty amines and the intrinsic effect of solvents in this system. This enzymatic catalytic one-pot three-component system has excellent functional tolerance, simple operation, and application potential for industrial production demonstrated by the gram scale experiment.

Assessing the sustainability and safety of polyethylene terephthalate (PET) liners for lead service lines (LSL) upgrades

Polyethylene Terephthalate (PET) liners have been proposed by industry as a more cost effective and less disruptive alternative to lead service lines (LSL) replacement. However, concerns have been raised about their aging under real-use conditions and their potential health and environmental impacts. In this study, two approaches were implemented. First, bench and pilot scale experiments were carried out to investigate the aging of a PET liner under conditions that simulate normal usage. Results show early surface oxidation and leaching of potentially hazardous metals (lead, zinc and titanium). No short-term fragmentation of the PET liner into microplastics was observed. Next, a life cycle assessment (LCA) compared the health and environmental impacts of three LSL upgrade alternatives: PET liners and full LSL replacement using either copper or PEX pipes. The installation phase was shown to be the main contributor to impact scores, while the benefits of PET liners are highly dependent on their lifespan. PEX pipes installed by torpedoing lower impacts as compared to PET liners and copper pipes for equal lifespan, while the use of PET liners remains less impactful regarding human health and ecosystem quality when a complete excavation is needed. LCA derived global human health effects due to ingestion of leached metals from PET liners, copper pipes and unreplaced LSL, and showed that PET liners and copper pipes significantly reduce health impacts by 14 and 80 DALY respectively compared to unreplaced LSL. Finally, the Integrated Exposure Uptake Biokinetic (IEUBK) model was used to assess the impact of lead exposure specifically for drinking water ingestion. Estimated Blood Lead Levels (BLL) in children and infants in households with long unreplaced LSL was up to 263.7% and 207.8% greater compared to either replacement with copper pipes or rehabilitation with PET liners, showing the clear benefits of corrective action. Combining experimental results, LCA and biokinetic modeling provides actionable information for utilities to select the best upgrade options, considering environmental, health and practical constraints, whilst identifying remaining data gaps. The relative benefits of PET liners should be carefully evaluated considering their lifespan under real-life conditions, the complete replacement costs after failure, and the growing evidence of micro- and nanoplastics (MNP) risks.

Avoid backtracking and burn your inputs: CONUS-scale watershed delineation using OpenMP

The Memory-Efficient Watershed Delineation (MESHED) parallel algorithm is introduced for Contiguous United States (CONUS)-scale hydrologic modeling. Delineating tens of thousands of watersheds for a continental-scale study can not only be computationally intensive, but also be memory-consuming. Existing algorithms require separate input and output data stores. However, as the number of watersheds to delineate and the resolution of input data grow significantly, the amount of memory required for an algorithm also quickly increases. MESHED uses one data store for both input and output by destructing input data as processed and a node-skipping depth-first search to further reduce required memory. For 1000 watersheds in Texas, MESHED performed 95% faster than the Central Processing Unit (CPU) benchmark algorithm using 33% less memory. In a scaling experiment, it delineated 100,000 watersheds across the CONUS in 13.64s. Given the same amount of memory, MESHED can solve 50% larger problems than the CPU benchmark algorithm can.

The Green Indium Patented Technology SCRIPT, for Indium Recovery from Liquid Crystal Displays: Bench Scale Validation Driven by Sustainability Assessment

Indium is considered a valuable and irreplaceable material for a variety of applications that improve the quality of human life. Due to its limited availability and the growing demand, it is mandatory to find sustainable solutions for indium recovery from end-of-life devices. The green indium patented technology SCRIPT (ITA202018000008207) focuses on recovering indium from ground LCD panels, developed through laboratory scale investigation. The process ensures high recovery efficiencies of indium (>90%), features a simple design, and fully exploits the solid residue with the production of a concrete for building applications. This manuscript presents a study focused on the validation and optimization of the patented SCRIPT technology at the bench scale, driven by sustainability assessment. Bench scale experiments successfully validated the technology, improving its technology readiness level. Furthermore, an environmental sustainability assessment highlighted the importance of treating the finest fraction, which has the highest indium concentration. Optimization tests at the bench scale demonstrated that water could be recirculated for more than five cycles. The economic sustainability tests highlighted that when the indium concentration in the material fed into the recycling plant is above 1000 mg/kg, the technology is cost effective and worth investment. Our study is fundamental for boosting indium recycling in the world. Moreover, our methodological approach represents a guideline for achieving sustainability goals within circular economy approaches for strategic metals in complex matrices.

Unsupervised learning bioreactor regimes

Efficient operation of bioreactors is crucial for the success of biomanufacturing processes. Traditional Computational Fluid Dynamics (CFD) simulations provide detailed insights but often involve lengthy computation times and complexity, hindering their practicality for real-time applications. This study introduces a novel multivariate unsupervised learning algorithm that clusters bioreactors into physically meaningful regions based on CFD-generated and real-world data. These clusters not only facilitate the determination of internal reactor regimes but also serve as a foundational step for developing compartment models. Our approach utilizes a custom k-means clustering algorithm, which ensures spatial continuity of clusters by incorporating geometric data, and optimizes the number of compartments to maximize physical significance and data retention. This optimization is guided by a Pareto front analysis, balancing the need for clear compartment definition with the preservation of maximum information from the dataset. The effectiveness and versatility of this methodology were verified through case studies involving a 202 m³ Rushton impeller bioreactor (steady state simulation) and an 840 m³ airlift reactor (dynamic simulation). In the airlift reactor, the clustering algorithm accounted for dynamic fluctuations by averaging the simulation results, providing a robust method for incorporating temporal variations into the compartment analysis. The findings highlight the advantages of 3-D compartmentalization in capturing the intricate dynamics of fluid motion and cellular activities, thereby advancing the design of bioreactors and scaling down experiments for more efficient industrial applications.