Changes In Size Distribution Research Articles

Numerical simulation of aerosol concentration effects on cloud droplet size spectrum evolutions of warm stratiform clouds in Jiangxi, China

Abstract. Changes in aerosol amount and size distribution significantly impact cloud droplet size distribution, as aerosols act as cloud condensation nuclei (CCNs) and influence the relative dispersion (ε) of cloud droplet spectra. Relative dispersion plays a key role in parameterizing cloud processes in general circulation models (GCMs) and microphysical schemes, affecting precipitation estimates and climate predictions. However, the effects of varying aerosol modes on cloud microphysics remain debated, depending on thermodynamic conditions and cloud type. This study simulates a warm stratiform cloud in Jiangxi, China, using the Weather Research and Forecasting (WRF) Spectra–Bin Microphysics scheme (SBM-FAST) from 18:00 on 24 December 2014 to 06:00 on 25 December 2014 (UTC). Satellite and aircraft observations were used to validate the simulation, showing good agreement in cloud structure. Sensitivity experiments were conducted by increasing nucleation, accumulation, and coarse-mode aerosols 5-fold and by reducing the total aerosol concentration to 1/5 of the control. Results show that higher aerosol concentrations enhance cloud formation and broaden droplet spectra, while lower concentrations suppress cloud development. Accumulation-mode aerosols increase small-droplet concentrations, while nucleation- and coarse-mode aerosols favor larger droplets. The correlation between ε and volume-weighted radius (Rv) shifts from positive to negative as Rv increases. This transition is driven by cloud droplet collision–coalescence, condensation, and activation. Increased accumulation-mode aerosol concentrations shift the ε–Rv correlation from negative to positive in the Rv range of 4.5–8 µm, while reduced aerosol concentrations strengthen the negative correlation. Regardless of different coalescence intensities, ε converges with the increase in number concentration of cloud droplets (Nc).

Effects of high-pressure and CaCl2 pretreatments on the salt taste-enhancing activity of hydrolysate derived from spent hen meat.

High-sodium intake has been proven to bring serious risks to public health. A potential sodium substitute of salt taste-enhancing hydrolysate (STEH) of protein has been focused on recently. The salt taste-enhancing activity (STEA) of STEH still needs to be improved. High-pressure and calcium chloride (CaCl2) pretreatments were reported to affect proteolysis and promote the release of bioactive peptides. Hence, we investigated effects of high-pressure and CaCl2 pretreatments on hydrolysis and STEA of STEH derived from spent hen. The pretreatments significantly influenced STEA of spent hen meat hydrolysate (SHH), especially 200 MPa pressure and 80 mmol L-1 CaCl2 pretreatments increased 27.1% salt taste intensity of SHH compared to that of blank (without pretreatments) according to sensory evaluation, the SHH umami also increased after pretreatments. In SHH, the proportion of peptides < 1000 Da increased up to 79.37% after the pretreatments compared to 73.68% of the blank. The degree of hydrolysis (DH) increased to 19.45% for moderate high-pressure (200 MPa) from 18.02% for blank, and the DH decreased after higher high-pressure and CaCl2 pretreatments, especially for CaCl2 in 80 mmol L-1. The change in particle size distribution of SHH has similar trends to DH. High-pressure and CaCl2 pretreatments increased STEA of SHH by affecting hydrolysis process. The STEA increase may be related to increased small-peptide proportion in SHH. Meanwhile, moderate high-pressure may promote protein unfolding and further increase DH according to particle size distribution of SHH. The combination of proteolysis and pretreatments of high-pressure and CaCl2 is a promising method to produce STEH. © 2024 Society of Chemical Industry.

Effect of particle gradation and rock block content on soil-rock mixture shear strength parameters

Soil-rock mixture (SRM) is highly inhomogeneous and loose geomaterial found in the quaternary formation, composed of a certain percentage of rock blocks, fine-grained soil, and pores. In Peninsular Malaysia, SRM can commonly be found in the granitic formation covering the mountainous areas where slope failures are prone to occur due to deep tropical weathering, heavy rainfall, and steep terrain. Numerous research studies have been conducted to investigate the mechanical behaviour of SRM, especially the influence of rock block content. However, the effect of particle size distribution has been studied in limited detail. This study uses sieve analysis, specific gravity, compaction, and direct shear box tests to determine the shear strength parameters of weathered type SRM with particle size distribution. The sample collected was divided into well-graded, poorly-graded, and gap-graded types of particle size distribution with 30%, 50%, and 70% rock block content, respectively. The percentage of rock block content is crucial in controlling the shear strength parameters. The specific gravity, dry density, optimum moisture content, and estimated porosity values measured show a considerable difference when the particle size distribution (PSD) and rock block content change. The findings also show that for a well-graded SRM, cohesion and friction angle values show a non-linear relationship against the rock block content. Meanwhile, as the rock block content increases, the cohesion decreases and inversely has an increment of friction angle for poorly-graded SRM. In contrast, the cohesion of gap-graded SRM increases when the rock block content increases. Hence, by understanding the influence of particle size distribution on the shear strength parameters of SRM, a better evaluation can be made in designing slope hazard mitigation.

Technology for removing PM2.5 in clean coal processes

Most countries primarily utilize thermal power to meet their energy needs. However, thermal power generation generates a substantial amount of pollutants, such as particulate matter (PM), SOX, and NOX. These pollutants not only damage backend turbines and related equipment but also pollute the environment; thus, controlling their emissions is critical.This study developed a system operating under high temperature by integrating heating, pneumatic conveying, dust particulate supply, and filter material transport systems. This setup enables the simulation of the entry of syngas with PM at the output of a gasification unit. The developed composite filtration system was analyzed under various operational parameters, including different temperatures, inlet air velocities, and mass flow rates of filter material, to examine the changes in the dust particulate size distribution at its outlet and its PM2.5 collection efficiency. In a series of tests, the collection efficiency of this system reached at least 95% at operating temperatures between 20°C and 600°C. Each 100°C increase in the operating temperature resulted in a 0.63% decrease in the PM2.5 collection efficiency. The findings of this study lay the foundation for the future development of high-temperature gas purification systems.

Detection and analysis of ship emissions using single-particle mass spectrometry: A land-based field study in the port of rostock, Germany

The regulation of ship emissions has become more restrictive due to their significant impact on global air quality, particularly in coastal regions. According to the International Maritime Organization (IMO) regulations, current restrictions mainly limit the sulfur content of the fuel mass to 0.5 % and 0.1 % respectively. In compliance with these regulations, exhaust SO2 cleaning systems (scrubbers) and new low-sulfur fuels are increasingly used. For comprehensive monitoring of ship emissions, advanced measurement techniques are demanded. Our study reports on the results of a land-based field campaign conducted in the port of Rostock, Germany. The chosen location strategically positions the measurement setup to capture all incoming and outgoing ships passing within a distance of up to 2 km. Potential ship exhaust plumes are indicated by rapid changes in particle number and size distribution monitored by an optical particle sizer (OPS) and a scanning mobility particle sizer (SMPS). Additionally, single-particle mass spectrometry (SPMS) was used to qualitatively characterize ambient single-particles (0.2–2.5 μm) by their chemical signatures. In a one-week time span, the exhaust plumes of 73 ships were identified. The high sensitivity of SPMS to transition metals and polycyclic aromatic hydrocarbons (PAH) in individual particles make it possible to distinguish between different marine fuels.

Pilot-scale study of turbid particle evolutional/removal characteristics during coagulation-sedimentation-filtration (CSF): Effects of coagulant dosage and secondary dosing after breakage

Considering the limitations of treated water turbidity, a thorough understanding of the changes in turbid particle size distribution during coagulation-sedimentation-filtration (CSF) is crucial for enhancing the removal efficiency of particulate and dissolved contaminants from raw water. In this study, a pilot-scale experimental system was utilized to track the evolution of turbid particles and assess how the characteristics of these turbid particles affected the quality of treated water in the CSF processes under varying cases of polyaluminum chloride (PAC) coagulant dosage and secondary coagulant dosage after breakage. It was found that differently from the role of PAC coagulant dosage (without high-shear breakage), different levels of secondary coagulant dosing after breakage had minimal influence on the aggregate structure produced by mechanical stirring flocculation. During the overall CSF processes, the changing trend in the total particle number for the filtered water appeared to be more consistent with the corresponding changing trend for the settled water, as the PAC coagulant dosage increased. In addition, the combined effects of shear-induced breakage and secondary dosing could not only improve the removal efficiency of organic matter after inclined-tube sedimentation following mechanical stirring flocculation, but also enhance the removal efficiencies of water turbidity and particulate matter through sand filtration. In order to reduce the frequency of backwashing and extend the service life of the filter media, greater emphasis should be placed on detecting and removing the number of smaller-sized particles existing in the sixth unit of the flocculation tank together with the effluent of the sedimentation tank.

Effects of In-Row Spacing on Yield, Tuber Size Profiles, Bruise Damage, and Crop Values for Cultivars Alturas, Clearwater Russet and Ranger Russet in the Columbia Basin

Variety selection and cultural management practices are the most common considerations for improved profitability in potato production systems. Planting density investigations have led to both within and between-row spacing recommendations to maximize profitability for commonly grown potato cultivars. Planting density can significantly alter tuber set, tuber size distribution, yield and profitability depending on end-use of the crop. However, rarely have such investigations included an assessment of the residual effects of changes in tuber size distribution on tuber bruising (blackspot and shatter bruise) and associated financial returns. The physics of impact injury suggests that larger tubers are more prone to tuber bruising than smaller tubers when dropped from a similar height. In this study we varied the in-row spacing of seed to investigate the extent to which the associated changes in tuber size distribution affect tuber bruising and crop values. The results demonstrated that: (1) the extent of tuber bruising was directly correlated with total marketable yield as altered by in-row spacing; (2) marketable yields decreased as in-row spacing increased; (3) while the absolute yield (MT ha−1) of bruised tubers increased with closer in-row spacing, the spacing-induced shifts in tuber size distribution had no effect on the percentage of bruised tubers as a proportion of total yield; (4) larger tubers were more prone to bruising; and (5) closer in-row spacing significantly improved financial returns for both processing and seed contracts despite the increase in bruise yield.

Changes of gluten protein composition during sourdough fermentation in rye flour

AbstractBackground and ObjectivesCeliac disease (CD) is an immune‐mediated condition triggered by gluten consumption. Although more studies stated that gluten proteins are partially degrading during sourdough fermentation, it is still unclear whether the CD toxic epitopes are affected. Our aim was to examine the effect of controlled sourdough fermentation on the gluten content and composition with different sourdough starters in rye flour.FindingsDespite significant changes in protein size distribution and a decrease in secalin types confirmed by high‐performance liquid chromatography methods, the enzyme‐linked immunosorbent assay results showed increased gluten content after fermentation. The incomplete degradation of gluten and the potential resistance of celiac toxic epitopes may explain our results. As part of the R5 antibody binding, epitopes are supposed to be unavailable in the native form of secalins; they might be released and become accessible in the smaller protein fragments.ConclusionsIn comparison of the effect of different starter cultures, the results show that the different microbiological composition of the sourdough samples might be the reason for the differences in the protein degradation.Significance and NoveltyResults highlight the importance of a deeper investigation of the effects of gluten protein degradation on CD toxicity and the standardization of the fermentation process.

Functional variations in efficiency of PSII during leaf ontogeny in the tropical plant Saraca asoca

Leaf ontogeny of tropical evergreen tree species lasts several months with changes in size, shape, colouration and internal tissue distribution of leaves. Leaf initiation in Saraca asoca generally occurs once in a year during February–April, followed by very limited leafing thereafter. We measured the rate of photosynthesis, chlorophyll a fluorescence, energy quenching and PSII functions during the leaf ontogeny process. Observations were taken up to 35 days after opening of lamina (DAOL). Significant increase in the synthesis and accumulation of photosynthetic pigments but negative net photosynthesis was noticed during initial days of the ontogeny. The leaf moved from heterotrophy to autotrophy with gradual improvement of PSII functions. The ratio of intercellular CO2 (Ci) and ambient CO2 (Ca) showed significant change at ≥11 DAOL. Increase in the age of the leaf (between 5 and 28 DAOL) caused decrease in O-J rise and corresponding increase in J-I and I-P rise as well as of fluorescence maximum (FM) of the OJIP curve. The improvement of the electron transport components of the donor side of PSII was seen with increase in the functional oxygen evolving complex. The functional improvements of the donor and acceptor side of PSII during leaf ontogeny are discussed.

Impact of PCLNPG Nanopolymeric Additive on the Surface and Structural Properties of PPSU Ultrafiltration Membranes for Enhanced Protein Rejection

This research explored the use of a partially cross-linked graft copolymer (PCLNPG) as an innovative nanopolymer pore-forming agent to enhance polyphenylsulfone (PPSU) membranes for protein separation applications. The study systematically examined the impact of incorporating PCLNPG at varying concentrations on the morphological and surface properties of PPSU membranes. A thorough characterization of the resulting PPSU-PCLNPG membranes was performed, focusing on changes in morphology, water affinity, porosity, pore size, and pore size distribution. The experimental findings demonstrated that the use of PCLNPG led to a significantly more porous structure, as confirmed by SEM analysis, with notable increases in porosity and pore size (nearly double). Additionally, the hydrophilicity of the PPSU membrane was remarkably enhanced. Performance evaluations revealed a substantial improvement in pure water flux, with the flux nearly tripling. The BSA retention was directly correlated with the concentration of the PCLNPG pore former for a loading range of 0.25–0.75 wt.%. The incorporation of PCLNPG also reduced the membrane fouling propensity by reducing both cake layer resistance (Rc) and pore plugging resistance (Rp). These results underscore the potential of PCLNPG-PPSU membranes for wastewater reclamation and nutrient recovery applications.

Effects of Mesozooplankton Growth and Reproduction on Plankton and Organic Carbon Dynamics in a Marine Biogeochemical Model

AbstractMarine mesozooplankton play an important role for marine ecosystem functioning and global biogeochemical cycles. Their size structure, varying spatially and temporally, heavily impacts biogeochemical processes and ecosystem services. Mesozooplankton exhibit size changes throughout their life cycle, affecting metabolic rates and functional traits. Despite this variability, many models oversimplify mesozooplankton as a single, unchanging size class, potentially biasing carbon flux estimates. Here, we include mesozooplankton ontogenetic growth and reproduction into a 3‐dimensional global ocean biogeochemical model, PISCES‐MOG, and investigate the subsequent effects on simulated mesozooplankton phenology, plankton distribution, and organic carbon export. Utilizing an ensemble of statistical predictive models calibrated with a global set of observations, we generated monthly climatologies of mesozooplankton biomass to evaluate the simulations of PISCES‐MOG. Our analyses reveal that the model and observation‐based biomass distributions are consistent ( = 0.40, total epipelagic biomass: 137 TgC from observations vs. 232 TgC in the model), with similar seasonality (later bloom as latitude increases poleward). Including ontogenetic growth in the model induced cohort dynamics and variable seasonal dynamics across mesozooplankton size classes and altered the relative contribution of carbon cycling pathways. Younger and smaller mesozooplankton transitioned to microzooplankton in PISCES‐MOG, resulting in a change in particle size distribution, characterized by a decrease in large particulate organic carbon (POC) and an increase in small POC generation. Consequently, carbon export from the surface was reduced by 10%. This study underscores the importance of accounting for ontogenetic growth and reproduction in models, highlighting the interconnectedness between mesozooplankton size, phenology, and their effects on marine carbon cycling.

Burning effects on the soils of the Mexican Maya Lowlands: Current evidence for understanding past events

The slash-and-burn cultivation system is a millenarian practice still used in many countries today, with significant environmental impacts. However, identifying evidence of this agricultural method in soil records is challenging due to natural and human factors that can obscure or alter fire signals. This challenge is particularly evident in the Yucatán Peninsula, where the ancient Maya practiced slash-and-burn agriculture in a dynamic tropical karst environment, making it difficult to pinpoint the origins and consequences of this practice. In this study, we use a recent agricultural burning in a karstic landscape in Chiapas as a model to understand alterations in soil properties. We then apply these insights to identify similar features at a Maya site on the Yucatán Peninsula, specifically at Coyote Quarry. For both cases, we conducted micromorphological analysis, soil physical-chemical characterization, thermogravimetry and differential scanning calorimetry analysis, and radiocarbon dating of mollusk shells, soil organic carbon, and charcoal fragments (the latter exclusively at Coyote Quarry). Our findings reveal significant effects on the soils from the Chiapas site post-burning, including changes in grain size distribution, pH, and total organic and inorganic carbon. These results were compared to those obtained from the Coyote Quarry soils and pedosediments. Key findings include micromorphological features, the presence of charcoal and other burned materials, and pyrogenic carbon identified through thermal analyses. The preservation of these burned features was facilitated by the typical karstic vertical soil erosion and redeposition as pedosediments in karstic depressions. The intrinsic association of the fire signals found in these karstic sinkholes and their radiocarbon dates enables us to link this evidence to the initiation of slash-and-burn agriculture by the Maya in the Yucatán Peninsula during the transition between the Archaic and Early Pre-Classic periods.

Studying the Gas Sensitivity and Magnetic Properties of Magnesium Ferrite Prepared by the Sol-Gel Route

Nickel-doped manganese–magnesium ferrite (NixMn0.25-xMg0.75Fe2O4) was prepared using the auto-combustion method. X-ray diffraction patterns showed a single ferrite spinel phase in all the prepared samples. The crystallite size ranged from 24.30 to 28.32 nm, increasing with increasing the Ni content. The porous structure of all the samples was verified with a scanning electron microscope. FE-SEM images were used to confirm the production of spherical or semi-spherical nanoparticles with little change in particle size distribution. The study revealed that the nanoparticles were small enough to behave superparamagnetically. According to the magnetic tests conducted with the VSM at room temperature, the hysteresis loop region is practically non-existent, indicating typical soft magnetic materials. In addition, the conductance responses of the magnesium ferrite nanocomposite were measured by exposing it to the oxidizing gas (NO2) at different operating temperatures. The results showed that the sensor with the nano ferrite sample of (x = 0.20) has a good sensitivity of 707.22% as well as response and recovery times.

Long Time Dynamics for Platinum Surface Area Loss in PEM Fuel Cells

Proton exchange membrane (PEM) fuel cells may emerge as a dominant clean energy source for heavy duty transport vehicles. Amongst other considerations, the lifetime performance of the fuel cell cathode catalyst layer is a key component of their future viability and a focus in the development of many proposed membrane electrode assemblies (MEAs). Typical targets of the lifetime of a PEMFC stack are on the order of thousands of hours of operation. However, running degradation tests spanning those long timescales is often impractical; and consequently, extensive work has been done developing and implementing accelerated stress tests (AST's) in order to screen proposed cathode catalyst materials for fuel cells.Much value is obtained by accurate and robust lifetime prediction models which are able bridge the gap between degradation from AST's in differential cells, and degradation of the catalyst layer in a fuel cell stack under realistic operating conditions. In other words, by parameterizing a model on short-time, subscale ASTs and extrapolating to a stack after tens of thousands of hours of operation. Commonly in such models, the electrochemically active surface area (ECSA) of platinum is used as the primary state-of-health parameter and predicted using either data-driven models or physics-based models. On one hand, data-driven models may be well suited to utilize large sets of stack data, but offer weaker extrapolation potential, conversely fitting physics-based models on global measurements of stack data is rarely a well-conditioned inverse problem.In this talk we present a scaling law on the long-time behavior of the ECSA obtained from analysis of governing physics equations from the literature. It is assumed that the primary loss mechanism is the coarsening of platinum particles, and the chief technique used is the method of averaging, which allows for the separation of two timescales: the short timescale of platinum oxide formation and dissolution, and the longer timescale over which the particle size distribution changes and a performance loss can be detected. The physics-derived asymptote for the ECSA evolution is then applied to several experiments and found to be in good agreement, allowing for a simple, streamlined lifetime prediction method for PEM fuel cells.

Title: Study of Structural Evolution of Silicon-Based Anodes in Lithium-Ion Batteries

The need for electrification across various sectors has led to increased demand for high-performance lithium-ion batteries (LIBs). Today’s commercial LIBs typically make use of a pure-graphite anode which offers long lifespans but a relatively meager capacity of 372 mAh/g. Silicon, by comparison, offers a theoretical capacity of 3600 mAh/g but generally suffers from short life spans due to numerous effects. Combining silicon and graphite active materials to form a composite anode can result in electrodes with improved capacities over pure-graphite systems and enhanced longevity over pure-silicon ones. However, introducing silicon to an otherwise stable graphite electrode can induce failure of the electrode partly due to the volumetric expansion/contraction that silicon experiences during lithiation/delithiation cycles. Understanding the morphological evolution of silicon particles in composite electrodes - particularly in a lithiated state - can yield a more comprehensive understanding of the interactions between the active materials which will contribute to the realization of anodes with improved capacities and lifespans. To date, characterizing lithiated silicon-containing anodes has been difficult owing to the reactivity of the lithiated materials and a lack of suitable methods to probe within an electrode’s bulk. In this work, we demonstrate recent successes in imaging lithiated silicon-composite and silicon oxide-composite electrodes via micro and nanoscale computed tomography (MicroCT, NanoCT) and electrochemical analysis to quantify (1) changes in particle size distributions over charge/discharge cycles, (2) lithium content in silicon particles as a function of depth from the electrode’s surface, (3) changes in particle morphology, and (4) electrode thickness. The development of this technique represents a significant step towards characterizing the physical behavior of silicon particles within electrodes without destroying the surrounding structures.

Utilization of Lead Nitrate to Enhance the Impact of Hydroxamic Acids on the Hydrophobic Aggregation and Flotation Behavior of Cassiterite.

Lead nitrate (LN) is frequently employed as an activator in the flotation of cassiterite using hydroxamic acids as the collectors. This study investigated the effect of LN on the hydrophobic aggregation of cassiterite when benzohydroxamic acid (BHA), hexyl hydroxamate (HHA), and octyl hydroxamate (OHA) were used as the collectors through micro-flotation, focused beam reflectance measurement (FBRM) and a particle video microscope (PVM), zeta potential, and the extended DLVO theory. Micro-flotation tests confirmed that LN activated the flotation of cassiterite using the hydroxamic acids as collectors. Focused beam reflectance measurement (FBRM) and a particle video microscope (PVM) were used to capture in situ data on the changes in size distribution and morphology of cassiterite aggregates during stirring. The FBRM and PVM image results indicated that the addition of LN could promote the formation of hydrophobic aggregates of fine cassiterite, when BHA or HHA was used as the collector, and reduce the dosage of OHA needed to induce the formation of hydrophobic aggregates of cassiterite. The extended DLVO theory interaction energies indicated that the presence of LN could decrease the electrostatic interaction energies (Vedl) and increase the hydrophobic interaction energies (Vhy) between cassiterite particles, resulting in the disappearance of the high energy barriers that existed between the particles in the absence of LN. Thus, cassiterite particles could aggregate in the presence of LN when BHA, HHA, or a low concentration of OHA was used as the collector.

Tail Morphology of Near-Sun Comet C/2020 F3 (NEOWISE)

We study the morphological changes of bright near-Sun comet C/2020 F3 (NEOWISE) using a series of multi-color wide-field images obtained in 2020 July 8–30, as the comet receded from 0.3 to 0.8 au from the Sun. Syndyne–synchrone modeling shows that the dusts that makes up the visible tail were mostly produced at and after perihelion. The images show changes of dust size distribution throughout the observations, with a gradual depletion of micron-sized particles. We discuss caveats in using the syndyne–synchrone model to study tail dynamics of comets at small perihelion distances. The r-band images consistently show a straight, non-dust tail throughout our observations that is likely to be made by neutral sodium atoms and H2O+ molecules.

Assessment of the effectiveness of coarse resolution fire products in monitoring long-term changes in fire regime within protected areas in South Africa

Although high-resolution satellite and in situ airborne observations are becoming a common data source for fire monitoring, reconstruction of the historical fire record is based on less suitable data. In many regions, managers and policy-makers rely solely on coarse resolution global fire datasets. This study assessed the suitability of readily available products to accurately depict several fire metrics by comparing them to the manually derived fire scars within three natural reserves in South Africa (2003–2020). Contrary to previous findings, we showed that MCD64A1 and FireCCI51 products detected the majority of the burned area (70–97 %) within protected areas and showed high temporal consistency. Additionally, active and burned area products accurately detected the length and the peak of the fire season. Nonetheless, we found neither medium nor coarse resolution data suitable for evaluating long-term changes in fire size distribution. Coarse resolution burned area products demonstrated a very limited capacity to detect fires smaller than 100 ha, while a lack of sufficient non-cloudy Landsat images led to substantial gaps in fire reconstruction, bringing an unknown level of uncertainties in fire metrics estimates. Similarly, the only available medium-resolution burned area product (GABAM) was unsuitable for fire monitoring since unmapped areas were classified as unburned, making no distinction between regions with an absence of data and an absence of fires. Meanwhile, the performance of FireCCILT11 was ranked the lowest among all the available fire products. Given the lack of resources in many protected areas in South Africa and the pressing need to evaluate current and historical fire management practices and policies, we conclude that, in the absence of a more accurate higher-resolution alternative, MCD64A1 was the most suitable product for capturing year-to-year fluctuations in fire activity and a combination of MODIS and VIIRS active fire products for monitoring changes in fire seasonality.

Intrinsic CO2 nanobubbles in alkaline aqueous solutions

Nanobubbles (NBs) and their derivative, bulk nanobubbles (BNBs), have been widely studied due to their potential wide range of applications. However, the stable existence of intrinsic NBs and BNBs in solutions is still controversial. This study investigates the existence and behaviour of unknown nano-entities in dilute alkaline solutions using Field-Flow Fractionation Multi-Angle Light Scattering (FFF-MALS), resulting in the first report of the presence, size distribution, and size distribution changes under different treatments. The results suggest that neutral and acidic pure solutions of salts at concentrations below the solubility product do not contain detectable nano entities. Alkaline solutions, on the other hand, such as carbonate buffer and sodium hydroxide, do contain nano scatterers in the range of ∼100 nm diameter that cannot be removed by boiling or filtration. Reducing the pH of the solutions or freezing reduces their number densities. The freeze-thaw procedure strongly suggests that these nano entities are BNBs. Zeta Nanoparticle Tracking Analysis (ZNTA) shows the zeta potential and the concentration in agreement with previous literature. It can be concluded that intrinsic BNBs in alkaline solutions are an integral part of the total nano-entity population. This study highlights the importance of considering intrinsic BNBs when investigating nanoparticles in alkaline solutions with analytical methods such as Static Light Scattering (SLS), which can detect low number densities in the original liquid state that may not be plausible by other detection methods due to their detection thresholds or acquisition of sample preparation methods of drying or freezing that do not allow real-time observations.

Ultrasonic Levitation for Airway Humidification.

This study employs the transmitter part of an ultrasonic proximity sensor to generate a powerful ultrasonic field for medical humidification. This field is created using an arrangement of small ultrasonic transmitter transducers configured in an acoustic levitator-style setup. As droplets pass through this ultrasonic field, they undergo disintegration, leading to an accelerated evaporation process. The research findings highlight a significant change in droplet size distribution due to ultrasonics, resulting in a notable increase in the rate of evaporation. As a result, this study presents a conceptual framework for reimagining humidification devices for lung therapeutic purposes through the utilization of simple sensor technology.