Process Intensification Research Articles

Wall-Immobilized Biocatalyst vs. Packed Bed in Miniaturized Continuous Reactors: Performances and Scale-Up.

Sustainable biocatalysis syntheses have gained considerable popularity over the years. However, further optimizations - notably to reduce costs - are required if the methods are to be successfully deployed in a range of areas. As part of this drive, various enzyme immobilization strategies have been studied, alongside process intensification from batch to continuous production. The flow bioreactor portfolio mainly ranges between packed bed reactors and wall-immobilized enzyme miniaturized reactors. Because of their simplicity, packed bed reactors are the most frequently encountered at lab-scale. However, at industrial scale, the growing pressure drop induced by the increase in equipment size hampers their implementation for some applications. Wall-immobilized miniaturized reactors require less pumping power, but a new problem arises due to their reduced enzyme-loading capacity. This review starts with a presentation of the current technology portfolio and a reminder of the metrics to be applied with flow bioreactors. Then, a benchmarking of the most recent relevant works is presented. The scale-up perspectives of the various options are presented in detail, highlighting key features of industrial requirements. One of the main objectives of this review is to clarify the strategies on which future study should center to maximize the performance of wall-immobilized enzyme reactors.

The application of natural language processing for the extraction of mechanistic information in toxicology

To study the ways in which compounds can induce adverse effects, toxicologists have been constructing Adverse Outcome Pathways (AOPs). An AOP can be considered as a pragmatic tool to capture and visualize mechanisms underlying different types of toxicity inflicted by any kind of stressor, and describes the interactions between key entities that lead to the adverse outcome on multiple biological levels of organization. The construction or optimization of an AOP is a labor intensive process, which currently depends on the manual search, collection, reviewing and synthesis of available scientific literature. This process could however be largely facilitated using Natural Language Processing (NLP) to extract information contained in scientific literature in a systematic, objective, and rapid manner that would lead to greater accuracy and reproducibility. This would support researchers to invest their expertise in the substantive assessment of the AOPs by replacing the time spent on evidence gathering by a critical review of the data extracted by NLP. As case examples, we selected two frequent adversities observed in the liver: namely, cholestasis and steatosis denoting accumulation of bile and lipid, respectively. We used deep learning language models to recognize entities of interest in text and establish causal relationships between them. We demonstrate how an NLP pipeline combining Named Entity Recognition and a simple rules-based relationship extraction model helps screen compounds related to liver adversities in the literature, but also extract mechanistic information for how such adversities develop, from the molecular to the organismal level. Finally, we provide some perspectives opened by the recent progress in Large Language Models and how these could be used in the future. We propose this work brings two main contributions: 1) a proof-of-concept that NLP can support the extraction of information from text for modern toxicology and 2) a template open-source model for recognition of toxicological entities and extraction of their relationships. All resources are openly accessible via GitHub (https://github.com/ontox-project/en-tox).

From bowls to pots: The dairying revolution in Northwest Turkey, a view from Barcın Höyük, 6600 to 6000 BCE

Research has identified Northwest Turkey as a key region for the development of dairying in the seventh millennium BCE, yet little is known about how this practice began or evolved there. This research studies Barcın Höyük, a site located in Bursa’s Yenişehir Valley, which ranges chronologically from 6600 BCE, when the first evidence of settled life appears in the Marmara Region, to 6000 BCE, when Neolithic habitation at the site ceases. Using pottery sherds diagnostic by vessel category and type, this paper aims at identifying which ones may have been primarily used to store, process, or consume dairy products. Organic residue analysis of selected samples helped address the process of adoption and intensification of milk processing in this region over time. The lipid residue data discussed in this paper derive from 143 isotopic results subsampled from 173 organic residues obtained from 805 Neolithic potsherds and suggest that bowls and four-lugged pots may have been preferred containers for processing milk. The discovery of abundant milk residues even among the earliest ceramics indicates that the pioneer farmers arrived in the region already with the knowhow of dairying and milk processing. In fact, these skills and the reliance on secondary products may have given them one of the necessary tools to successfully venture into the unfarmed lands of Northwest Anatolia in the first place.

Radar-Based Precipitation Nowcasting Based on Improved U-Net Model

Rainfall nowcasting is the basis of extreme rainfall monitoring, flood prevention, and water resource scheduling. Based on the structural features of the U-Net model, we proposed the Double Recurrent Residual Attention Gates U-Net (DR2A-UNet) deep-learning model to carry out radar echo extrapolation. The model was trained with mean square error (MSE) and balanced mean square error (BMSE) as loss functions, respectively. The dynamic Z-R relationship was applied for quantitative rainfall estimation. The reference U-Net model, U-Net++, and the ConvLSTM were used as control experiments to carry out radar echo extrapolation. The results showed that the model trained by BMSE had better extrapolation. For 1 h lead time, the rainfall nowcasted by each model could reflect the actual rainfall process. DR2A-UNet performed significantly better than other models for intense rainfall, with a higher extrapolation accuracy for echo intensity and variability processes. At the 2 h lead time, the nowcast accuracy of each model was significantly reduced, but the echo extrapolation and rainfall nowcasting of DR2A-UNet were better.

Impacts of riverbed aggradation on groundwater regime in a lowland area

Abstract In this study, the influence of riverbed silting on the groundwater regime in a lowland area was investigated. The study area is situated at the Rye Island (Žitný Ostrov) in Slovakia, along the Gabčíkovo – Topoľníky canal, which is part of the drainage-irrigation canal system constructed in this locality. The Rye Island is an area with very low slope (0.25 10–4) and good climatic conditions for aquatic vegetation, therefore the canals are influenced by intensive silting processes. The spatial and temporal patterns of surface water – groundwater exchange are significantly influenced by the thickness of riverbed sediments and their permeability. The aim of this study was to evaluate the thickness and hydraulic conductivity of bed sediments in the Gabčíkovo – Topoľníky canal and to examine their influence on the groundwater – surface water interaction in the area. The hydraulic conductivity of the sediments was assessed from undisturbed samples by the falling head method. The obtained data were used for numerical simulations of groundwater heads by the TRIWACO model for different drainage and infiltration resistance conditions in the area of interest. The results of this study can support the planning of canal maintenance.

Doors, Floors, Street

This paper, divided in five sections, is supported by established theoretical background. The paper points to the idea of human emancipation and to the potential role of architecture in helping the development of a more just and egalitarian society. The terms and concepts that are used in this essay have something in common; although they refer to different intellectual and disciplinary contexts, they have overlapping features which are critical to the understanding of an active, participatory culture in everyday life as a necessary aspect of society. People must take charge of their own lives and of the immediate conditions of living of their surroundings. The idea of co‑creation that is presented more fully in Section 5 benefits from the discussions in previous sections about the private and public space, the right to the city, Michel de Certeau’s views on walking, and Reyner Banham’s concept of the responsive environment. Co-creation is participation in its ultimate form. The fundamental idea is to plan and build a better world and better cities collectively. To make this easier, architects should also co-create more adaptable, controllable, and responsive buildings and urban spaces. Co-creation must be fostered, using intensive participatory processes, to define certain features of what is being done or built. However, this struggles against all odds to become a common practice in public policy. The search for social justice in the city still has a long way to go. Having said this, architecture and urban design are too important to be left out; they may not change the world but may help to make it better.

Process Intensification of the Continuous Synthesis of Bio-Derived Monomers for Sustainable Coatings Using a Taylor Vortex Flow Reactor

Process Intensification of the Continuous Synthesis of Bio-Derived Monomers for Sustainable Coatings Using a Taylor Vortex Flow Reactor

All Her Sons: Politics and Gender in the Jewish Cult at Rachel’s Tomb of the Last Three Decades

ABSTRACT The following paper explores the evolution of the cult of Rachel the Matriarch and its main folktales from the 1990’s until the present day. Whilst folktales surrounding the Biblical matriarch date back to the Rabbinic era, from the mid-nineteenth century onwards a unique Jewish cult at Rachel’s Tomb in Bethlehem significantly intensified. These rites, which were mostly female-led, were analyzed in a series of previous studies, most of which traced their development from their inception up to the 1990s. Since the Oslo Accords, however, the rituals and rites along with the folktales have evolved in profound ways. My research demonstrates the degree to which the political sphere impacts modern day Israeli-Jewish folk traditions, including bringing about the establishment of new traditions. Specifically, I argue that the rites, in the past mostly female-led, due to the increasing political significance of the cult, have undergone an intense process of masculinization.

An Exploratory Study of Food Waste in the Hospitality Industry of Pokhara

One-third of the global food production is wasted globally. Food production is a resource intensive process and safe disposal of food wasted requires additional resources. In tourism industry food is just more than fulfillment of basic needs. Food is linked with the experience. Food wastage in hospitality is accepted as a major challenge with multifaced consequences and awareness to address the issue of food waste is also increasing. In the context of developing countries like Nepal the topic is still under-studied. Therefore, this study is focused on owners and managers perspective on food wastage in tourism industry of Pokhara with the objectives of identifying current composition and causes of food waste and established approaches to mitigate it. This study was carried out with key informants’ in-depth interview and on-site observations. Unrealistic expectations, unsustainable consumption patterns, lack of general public awareness and management limitations on wastage controlling were major themes identified by the study. The findings call for quantitative study in mass scale to know the exact situation of the food waste in hospitality industry of Pokhara.

Effect of pH and temperature on tropane alkaloids within a processing strategy to provide safe infant cereal-based food

Tropane alkaloids (TAs) are secondary metabolites from weeds that can contaminate cereals and vegetables during harvest. Due to their toxicity, the Regulation (EC) 2023/915 sets maximum levels for atropine and scopolamine in cereal-based foods for infants containing millet, sorghum, buckwheat or their derived products. The aim of this study was to evaluate the effect of pH and temperature on the stability of TAs, as possible parameters in thermal processing to mitigate this chemical hazard in cereal-based infant food. The effect of pH (4 and 7) and temperature (80 °C and 100 °C) was assessed in buffer solutions. Also, treatment at 180 °C was performed in spiked and naturally incurred millet flour to assess the effect of high temperature, simulating cooking or drying, on the stability of TAs in the cereal matrix. The fate of 24 TAs was assessed by UHPLC-MS/MS. TAs showed high thermostability, although it was variable depending on the specific compound, pH, temperature and treatment time. In buffer solutions, higher degradation was found at 100 °C and pH 7. In spiked millet flour at 180 °C for 10 min, scopolamine and atropine contents decreased by 25 % and 22 %, similarly to other TAs which also showed a slow thermal degradation. Atropine, scopolamine, anisodamine, norscopolamine, scopine and scopoline were found in naturally contaminated millet flour. Interestingly, naturally incurred atropine was more thermostable than when spiked, showing a protective effect of the cereal matrix on TAs degradation. The present results highlight the need for an accurate monitorization of TAs in raw materials, as this chemical hazard may remain in infant cereal-based food even after intense thermal processing.

Multiphysics performance of surrogate models on skewed pole surface-mounted permanent magnet motors

Purpose Evaluating the multiphysics performance of an electric motor can be a computationally intensive process, especially where several complex subsystems of the motor are coupled together. For example, evaluating acoustic noise requires the coupling of the electromagnetic, structural and acoustic models of the electric motor. Where skewed poles are considered in the design, the problem becomes a purely three-dimensional (3D) multiphysics problem, which could increase the computational burden astronomically. This study, therefore, aims to introduce surrogate models in the design process to reduce the computational cost associated with solving such 3D-coupled multiphysics problems. Design/methodology/approach The procedure involves using the finite element (FE) method to generate a database of several skewed rotor pole surface-mounted permanent magnet synchronous motors and their corresponding electromagnetic, structural and acoustic performances. Then, a surrogate model is fitted to the data to generate mapping functions that could be used in place of the time-consuming FE simulations. Findings It was established that the surrogate models showed promising results in predicting the multiphysics performance of skewed pole surface-mounted permanent magnet motors. As such, such models could be used to handle the skewing aspects, which has always been a major design challenge due to the scarcity of simulation tools with stepwise skewing capability. Originality/value The main contribution involves the use of surrogate models to replace FE simulations during the design cycle of skewed pole surface-mounted permanent magnet motors without compromising the integrity of the electromagnetic, structural, and acoustic results of the motor.

Advances in design of internals: Applications in conventional and process intensification units

Internals within reactors play an important role in the chemical industry, and numerous studies focus on their investigation and development. This review discusses the application of internals in both conventional and Process Intensification (PI) units, including stirred tanks, fluidized beds, bubble columns, tubular vessels, trickle beds, spinning disks, rotating packed beds, rotating fluidized beds, and microreactors. It emphasizes enhancing mass and heat transfer through internals such as baffles, packing, heat exchange elements, and wall modifications. Recurring themes include phase distribution, interfacial area, slip velocities, heat transfer, and pressure drop. While internals offer benefits, challenges such as fouling and catalyst attrition are acknowledged, yet often under-quantified. Practical aspects, including manufacturing and safety, are often overlooked. The review highlights the urgent need for comprehensive evaluations, incorporating detailed Computational Fluid Dynamics (CFD) simulations and experimental studies. Based on previous research, this work aims to provide insights into innovative reactor designs that ultimately lead to optimal efficiency and energy balance in chemical processes.

Machine learning-assisted effective thermal management of rotor-stator systems

Rotor-stator systems are widely used to facilitate highly effective energy management and process intensification but have complex design characteristics, such as skittish flow and heat transfer. Due to the difficulty in obtaining heat transfer data for thermal management of rotor-stator systems, uneconomical designs with large margins often occur. Here, we propose a comprehensive design process using machine learning guided by convective heat transfer experimental data. We organize domain knowledge involving advection and convective heat transfer using a test rig employing a naphthalene sublimation method on large surfaces. Detailed heat transfer data elucidates that local thermal-fluid characteristics are non-linear as the operating conditions change, which is supported by numerical simulation models. We develop a machine learning-based heat transfer prediction model using pure experimental data and derive the optimal algorithm model. Thermal analysis via 2D thermal circuits provides an effective design process and enables rapid quantified evaluation of critical performance considerations. An improved rotor-stator system simultaneously achieves high heat flux of 1.9 kW/m2 and low thermal resistance of 17.1 K/W to both disks. We expect our experiment-based machine learning-assisted thermal management will serve as a robust and informative indicator for improving the efficiency and feasibility of applications with multivariate thermal-fluid systems.

Quantification of water, soil and nutrient losses in the Farinha river basin, Carolina - MA, in the Cerrado biome

Natural resources, such as soil and water, play a crucial role in sustaining life on Earth. When used appropriately, these resources can mitigate environmental impacts. However, inadequate soil management practices can result in negative effects, such as the intensification of erosion processes and significant losses of soil, water and nutrients essential for plant growth. Thus, considering that the Farinha River basin - MA is located in the Cerrado biome and has a large part of its area occupied by highly erodible soils, the aim was to quantify water, soil and nutrient losses using a rainfall simulator. The experimental design adopted was entirely randomised (DIC), in a bifactorial scheme with 5 replications. Factor 1 considered two types of soil management systems (Anthropised Area and Non-Anthropised Area), while factor 2 involved three simulated rainfall intensities (80mm.h-¹, 110mm.h-¹ and 130mm.h-¹). The response variables assessed were losses of water, soil and nutrients and organic matter.The averages were subjected to analysis of variance and, if significant, the Tukey test was applied at 5% probability using Past 4.03 software. The results indicated significant losses of soil, water and nutrients associated with both the soil management system and the rainfall intensities, as well as making it possible to quantify the nutrients lost in runoff water on site. The conclusion is that the combination of inadequate soil management practices and intense rainfall can exacerbate erosion processes and the leaching of macro and micronutrients, resulting in an increasing need to incorporate fertilisers and correctives into agroforestry activities. Furthermore, it is important to emphasise that water erosion also contributes to an increase in soil and nutrient loss, which can lead to adverse environmental impacts, such as contamination of water resources and degradation of soil quality.

Hydrogen production in protruded millisecond microchannel reactors by catalytically reforming methanol

Flow of a fluid past a body is a very complicated phenomenon. Computational fluid dynamics is used for studying the characteristics of flow past an array of hemispherical protrusions that is disposed on the wall surfaces of a millisecond microchannel reactor. Protrusions can be used to improve the transport processes involved, but the causes of the phenomena are still incompletely understood. Parametric analyses are performed under different sets of circumstances to delineate the role of geometric features and operation conditions in reactor performance. Dimensionless quantities are used to simplify the characterization of the reactor system with multiple interacting transport phenomena. The mechanisms involved in the intensified processes are analysed, and performance improvement recommendations are presented. The results indicate that the protruded reactor behaves effectively and good yields can be obtained with only milliseconds residence of the mixtures within the channels. The reactor offers the unique advantage for hydrogen production from methanol in that process intensification is realized while preserving the energy balance between the exothermic and endothermic processes. However, the flow rates, feed compositions, and channel dimensions must be adjusted as needed to maximize production of hydrogen and minimize pressure drops. While the thermal diffusivity dominates the overall reactor behaviour, expectable compromises have to be made between hydrogen productivity and pressure drop. The results have implications for hydrogen production and beyond for the study of transport phenomena in microchemical systems.

Investigation on flow and heat transfer characteristics of latent functionally thermal fluid for axisymmetric flows

The utilization of heat exchangers in energy and industrial production is vital for heat exchange and transfer. The latent functionally thermal fluid (LFTF), due to its exceptional properties, can be effectively utilized in double-pipe heat exchanger as a heat transfer fluid. This study delves into the convective and heat transfer characteristics of LFTF in symmetric flow conditions. Employing the lattice Boltzmann method (LBM), various dimensionless parameters are examined, including the height-to-diameter ratio (HDR) and inner diameter size. The results show that higher Rayleigh and Stefan numbers lead to more intense reactions and heat transfer processes. Additionally, a phase change temperature of 0.7 results in a total melting time that is 1.5 times longer than at a phase change temperature of 0.1. As the inner diameter increases, the average Nusselt number decreases faster, resulting in a shorter total melting time. Specifically, when the HDR is 0.5, the total melting time is 47.61% shorter compared to an HDR of 2. This is due to the fact that the temperature collects in the upper part of the study area resulting in faster melting in the upper part and hence shorter complete melting time the smaller the HDR. In summary, understand these relationships is crucial for optimizing heat transfer processes in industrial applications.

Co-occurrence of elevated arsenic and fluoride concentrations in Wuliangsu Lake: implications for the genesis of poor-quality groundwater in the (paleo-)Huanghe (Yellow River) catchment, China

The co-occurrence of high As and F concentrations in saline groundwater in arid and semi-arid regions has attracted considerable attention. However, the factors determining the elevated concentrations of the two elements in surface water in these regions have not been sufficiently studied, and their implications for the poor-quality of local groundwater (high levels of As, F, and salinity) are unknown. A total of 18 water samples were collected from Wuliangsu Lake, irrigation/drainage channels, and the Huanghe (i.e., Yellow River) in the Hetao Basin, China. The pH, concentrations of As and F as well as those of other major elements, and stable isotope (H and O) compositions were analyzed. The water samples had a high pH (7.85–9.01, mean 8.25) and high TDS (402–9778 mg/L, mean 1920 mg/L) values. In six of the 10 lake samples, As concentration was above 10 μg/L (maximum 69.1 μg/L) and, in one of them, F concentration was above 1.5 mg/L. Interestingly, the high As, F, and TDS values simultaneously detected in the lake water were similar to those previously reported in local groundwater, and all water samples showed a significant positive correlation between As and F concentrations (R2 = 0.96, p < 0.01), except for two samples with abnormally high Ca2+ levels. The results of stable isotope analysis and Cl/Br ratios suggested that the lake experienced strong evaporation, which is consistent with the high TDS values. Evaporative concentration is suggested as the main factor contributing to the elevated As and F concentrations in the lake water. In addition, the major ions (e.g., Na+, Cl−, HCO3−, and OH−) and pH in the lake water increased during evaporation, leading to desorption of As and F. Thus, the evaporation process, including evaporative concentration and desorption, was considered primarily responsible for the elevated As and F in the lake water. Based on the results of this study, we presume that the paleolakes in the study area have experienced intense evaporation process. As a result, As, F, and major elements accumulated in sediments (or residual lake water) and were buried in the fluvial basins; then, they were released into the groundwater through multiple (bio)hydrogeochemical processes. By combining the results of this study with those obtained from previous groundwater analyses, we propose a new hypothesis explaining the origin of elevated As and F concentrations in saline groundwater in arid and semi-arid regions.

Bone cement in total hip arthroplasty – Is it really green?

BackgroundTotal hip replacement (THR)is typically cemented, cementless or hybrid depending on patient factors and surgeon preference. To date no studies have evaluated waste generated with each of these procedures in relation to implant choice, and particularly waste related to consumables. We aimed to quantify the volume; type and ability to recycle this waste and suggest potential strategies for reducing the overall waste related to consumables in THR. MethodThis was a prospective review of all waste related to consumables in THR. The waste was weighed using a Salter 1066 BKDR15 scale, accurate to the nearest 1 ​g. The primary outcome was the amount of waste generated per case depending on implant choice (cemented vs. uncemented). Secondary outcomes included: proportion of clinical waste and proportion of recyclable waste. ResultsCemented THR generated a total of 1.89 ​kg of waste compared to 775 ​g for an uncemented THR. Cemented THR generated significantly more sterile (hazardous) waste than uncemented THR both as overall volume and as a proportion 763 ​g (40%) vs 76 ​g (10%). Significantly more of the waste related to uncemented THR was amenable to being recycled through conventional waste streams with simple changes in theatre 672 ​g (86%) compared to 989 ​g (52%) with cemented THR. Between 20 and 30% of waste packaging for both types of surgery compromised information booklets. ConclusionCemented hip replacement generates significantly more waste from consumables than uncemented and a greater amount of this waste is hazardous requiring intensive processing. For both implants a significant proportion of waste can be recycled with simple process changes in theatre. Industry partners have a responsibility to minimise unnecessary packaging and work with surgeons to improve sustainability.

Application of Ensemble Algorithm Based on the Feature-Oriented Mean in Tropical Cyclone-Related Precipitation Forecasting

Tropical cyclones (TCs) are characterized by robust vortical motion and intense thermodynamic processes, often causing damage in coastal cities as they result in landfall. Accurately estimating the ensemble mean of TC precipitation is critical for forecasting and remains a foremost global challenge. In this study, we develop an ensemble algorithm based on the feature-oriented mean (FM) suitable for spatially discrete variables in precipitation ensembles. This method can adjust the locations of ensemble precipitation fields to reduce the location-related deviations among ensemble members, ultimately enhancing the ensemble mean forecast skill for TC precipitation. To evaluate the feasibility of the FM in TC precipitation ensemble forecasting, 18 landing TC cases in China from 2019 to 2021 were selected for validation. For precipitation forecasts of the landing TCs with a varying leading time, we conducted a comprehensive quantitative evaluation and comparison of the precipitation forecast skills of the FM and arithmetic mean (AM) algorithms. The results indicate that the field adjustment algorithm in the FM can effectively align with the TC precipitation structure and the location of the ensemble mean, reducing the spatial divergence among precipitation fields. The FM method demonstrates superior performance in the equitable threat score, probability of detection, and false alarm ratio compared with the AM, exhibiting an overall improvement of around 10%. Furthermore, the FM ensemble mean shows a higher pattern of the correlation coefficient with observations and has a smaller root mean square error than the AM ensemble mean, signifying that the FM method can better preserve the characteristics of the precipitation structure. Additionally, an object-based diagnostic evaluation method was used to verify forecast results, and the results suggest that the attribute distribution of FM forecast objects more closely resembles that of observed precipitation objects (including the area, longitudinal and latitudinal centroid locations, axis angle, and aspect ratio).

Effect of water content in ethanol on flame front wrinkling and curvature in a spark-ignition engine using OH PLIF imaging

The production of ethanol fuel involves separating water and ethanol by distillation and dehydration in an energy intensive process. To reduce the carbon footprint, hydrous ethanol is seen as a promising alternative. This study focused on the effect of water content in ethanol on flame development in a single-cylinder optical spark-ignition engine. Ethanol with 0%, 4% and 10% water content per volume was used with Port Fuel Injection (PFI) and Direct Injection (DI) for homogeneous and heterogeneous mixture preparation. Tests were also conducted with iso-octane for comparison. Flames captured by Planar Laser Induced Fluorescence (PLIF) of OH were spatially filtered to remove scales larger than the flame size, then the flame brush was quantified in terms of thickness, crossing frequency between instantaneous and filtered contours, and curvature. Increasing water content resulted in slower flame growth, with 10% hydrous exhibiting marginally higher flame speed than iso-octane. PFI led to faster flame growth and thicker flame brushes than DI at the same timing after ignition. When the brush thickness was normalised by flame radius, all hydrous fuels and iso-octane exhibited similar values with PFI, whilst anhydrous ethanol exhibited the thickest normalised brush. The alcohols maintained similar normalised thicknesses with DI and iso-octane exhibited the thickest normalised brush. When flames of the same radii were considered with PFI at the same timing, the fuels with sequentially lower laminar burning velocity were associated with larger crossing frequency. For PFI, increasing water content resulted in decreased flame roundness irrespective of size, with the 4% hydrous and iso-octane exhibiting similar values. With DI, anhydrous ethanol flames were rounder than the 4% hydrous when averaged over all cycles, but marginally rounder than the 10% hydrous and iso-octane. Increasing water content widened the curvature distribution and increased the mean with PFI. Flame roundness decreased with increase in mean curvature and Lewis number for both PFI and DI.