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Acting as substrates for heterogeneous nucleation, native oxides in Al–Mg alloys have shown their potential for grain refinement. However, the limited knowledge about the nature of the oxides in Al–Mg alloys impedes the widespread application as native grain refiners. The aim of this work is to comprehensively investigate the native oxides in Al–Mg alloys through electron microscopy. Our results show that the predominant inclusions in Al–Mg alloys are oxides in three types of oxide films at the micrometer scales: young films, old films and oxide skins. All oxide films consist of discrete oxide particles of three types in nanometer scale depending on the Mg contents: γAl2O3 (< 0.4 wt.%), MgAl2O4 (0.08–3.5 wt.%) and MgO (> 2 wt.%). Specifically, MgAl2O4 particles have sizes ranging from a few tens to a few hundreds nanometer and possess an elementary shape of octahedron faceted by {111} planes. In Al–Mg alloys, the native oxides have a lognormal size distribution, with the average mean size fluctuating in accordance with the oxide configurations as Mg content varies. The agglomerating feature causes inhomogeneous sampling, and dual-peak lognormal curves are found for low-Mg-content alloys (0.08/0.4%), which could be eliminated by increasing the Mg content (2.0/3.5%) or by using the high-shear melt conditioning (HSMC) technology. Understanding the native oxides in Al–Mg alloys shall provide instructions on their application in grain refinement. [ABSTRACT FROM AUTHOR]

Human pluripotent stem cells (hPSCs) hold promise for regenerative medicine to replace essential cells that die or become dysfunctional. In some cases, these cells can be used to form clusters whose size distribution affects the growth dynamics. We develop models to predict cluster size distributions of hPSCs based on several plausible hypotheses, including (0) exponential growth, (1) surface growth, (2) Logistic growth, and (3) Gompertz growth. We use experimental data to investigate these models. A partial differential equation for the dynamics of the cluster size distribution is used to fit parameters (rates of growth, mortality, etc.). A comparison of the models using their mean squared error and the Akaike Information criterion suggests that Models 1 (surface growth) or 2 (Logistic growth) best describe the data. [ABSTRACT FROM AUTHOR]

Horses stay in different types of stables; especially during the cold season, they stay inside for most of the day. A stable is also a place where many people spend quite a lot of time either as employees who care for and train horses or as equine enthusiasts. Keeping horses in stables causes their constant exposure to high concentrations of particulate matter (PM) and molds in the air inside these facilities. The study was conducted in Udórz Stud Farm located in the southern region of Poland. It was carried out in two different types of stables: three runners and two box stables. The study continued for 2 years; samples were collected in each season of the year. The following devices were used: a six-stage Andersen-Graseby cascade impactor, the DustTrak™ II Aerosol Monitor 8530. The obtained results allowed for the conclusion that horses kept in box stables are exposed to lower concentrations of molds and yeasts than those kept in runners. Molds dominated in the stable air during humid periods—spring and autumn—while yeasts were more prominent during summer and winter. It was observed that cleaning stables reduces the morphotic elements of fungi in the air, even though it results in a higher level of particulate matter in the stable air. It should be noted that microclimate conditions were optimal for horses practically throughout the whole year. Key points: • In stables, there is a high level of air intoxication, both by yeast and by mold fungi • The concentrations of fungi in the air depend on the season and the stable cleaning procedure • The PM concentrations depend on the type of stable [ABSTRACT FROM AUTHOR]

This study, conducted in Debrecen, Hungary, aimed to analyse atmospheric particulate matter (APM or PM) through radiocarbon and PIXE analyses during the winter smog (23–25 January) and spring (15–18 May) seasons. The information presented in this pilot study aims to provide insight into the importance of utilising detailed characteristics of the mass size distributions of fossil carbon (ff) and contemporary carbon (fC) content. Additionally, it seeks to compare these characteristics with the size distributions of various elements to enable even more accurate PM source identification. In winter, APM concentrations were 86.27 μg/m3 (total), 17.07 μg/m3 (fC) and 10.4 μg/m3 (ff). In spring, these values changed to 29.5 μg/m3, 2.64 μg/m3 and 7.01 μg/m3, respectively. Notably, differences in mass size distribution patterns were observed between the two seasons, suggesting varied sources for contemporary carbon. Biomass burning emerged as a crucial source during the smog period, supported by similar MMAD (Mass Median Aerodynamic Diameter) values and a strong correlation (r = 0.95, p < 0.01) between potassium and fC. In spring, a significant change in the concentration and distribution of fC occurred, with a broad, coarse mode and a less prominent accumulation mode. Ff was found to have similar distributions as PM, with nearly the same MMADs, during both periods. Finally, a comprehensive comparison of modal characteristics identified specific sources for the various components, including biomass burning, vehicle exhaust, coal and oil combustion, vehicle non-exhaust, road dust, tyre abrasion, mineral dust and biogenic emission. This study showcases how using radiocarbon and PIXE analysis in size distribution data can enhance our understanding of the sources of PM and their effects on different size fractions of PM. [ABSTRACT FROM AUTHOR]

In aquaculture, biological hazards can be exposed to workers in the form of bioaerosols. This study is to evaluate the level of biological hazard exposure and to provide fundamental data for the health management of aquaculture workers in Korea. A field survey was conducted to measure bioaerosol exposure at ten aquaculture farms in areas where Korean aquaculture is concentrated. Airborne bacteria and fungi with size distribution and identification were measured by simultaneously monitoring temperature and relative humidity. Particularly, high concentrations of airborne bacteria and fungi were observed in farms G and H. Compared to the standards set by the Korean Ministry of Environment, both total airborne bacteria and fungi concentrations exceeded the limit in farms G and H, with the airborne fungi concentration showing four times higher than the standard. As a cause, it is believed to be the quantity and form of work. In size distribution, it was similar to previous study. However, the respirable size range accounted for more than 50% of total concentration, so extra caution should be needed. Staphylococcus spp., Micrococcus spp., Corynebacterium spp., and Bacillus spp. are dominant species for airborne bacteria whereas Cladosporium spp., Penicillium spp., Aspergillus spp., and Alternaria spp. are dominant species for airborne fungi. Most farms had concentrations below the standard, but two farms exceeded the standard, likely due to work type. And some caution is needed for respirable size bioaerosol. Further research is needed, considering additional factors such as tank type, fish species, and type of works. [ABSTRACT FROM AUTHOR]

Purpose: A comparative assessment was performed to evaluate the potential of particle sizing by an ensemble based conventional dynamic light scattering (DLS) technique and an emerging technology based on tunable resistive pulse sensing (TRPS) using particle by particle approach by evaluating three different types of vaccine formulations representing three case studies and showing the limitation of each technique, instrument variability, sensitivity, and the resolution in mixed population. Methods: Three types of in-house vaccine formulations- a protein antigen, an outer membrane vesicle and viral particles were simultaneously evaluated by TRPS based Exoid and two DLS instruments-Zetatrac and Zetasizer for particle size distribution, aggregates, and resolution of polydisperse species. Results: The data from first case study show the risk of possible size overestimation and size averaging in polydisperse samples in DLS measurements which can be addressed by the TRPS analysis. It also shows how TRPS may be utilized only to large size antigens due to its limited size range. The second case study highlights the difference in the sensitivities of two DLS instruments working on the same principle. The third case study show that how TRPS can better resolve the large aggregate species compare to DLS in polydisperse samples. Conclusion: This analysis shows that TRPS can be used as an orthogonal technique in addition to conventional DLS based methods for more precise and in-depth characterization. Both techniques are efficient in size characterization and produce comparable results, however the choice will depend on the type of formulation and size range to be evaluated. [ABSTRACT FROM AUTHOR]

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 μg/m3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 μg/m3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 μg/m3). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 μm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 μg/m3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10−5 to 1.79 ×10−4. During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10−4, with a rate of 96%. [ABSTRACT FROM AUTHOR]

Atmospheric particles have been significantly affecting urban air quality and urban-oriented living in an increasing share of the population in Bangladesh. This study assessed the concentration of PM1.0, PM2.5, and PM10 in Khulna, one of the largest cities in Bangladesh located near the Bay of Bengal. The maximum average concentrations were recorded 415 ± 184.01 µg/m3 for PM10, 302 ± 109.89 µg/m3 for PM2.5, and 143 ± 45.05 µg/m3 for PM1.0. These values are several times higher than the World Health Organization air quality standard and Bangladesh National Ambient Air Quality Standard. According to the size and fractional distribution of PM, most of the monitoring locations were dominated by fine particles. Carcinogenic and non-carcinogenic risks due to exposure to ambient PM1.0, PM2.5 and PM10 were also quantified to illustrate the relevant potential human health risks. The excess lifetime cancer risk (ELCR) values of PM1.0 ranged from 8.6E0–4 to 6.0E–07 and PM2.5 varied between 8.6E–04 and 6.0E–07 exceeded the allowable limit at every location indicating the potential cancer-developing risk to the urban population. The health quotient (HQ) values also crossed the least permissible value at most of the locations depicting strong non-carcinogenic risks. Average HQ values of PM2.5 varied from 1.07 to 20.13 while PM10 ranged from 0.44 to 8.3. This research revealed children and elderly people as the most vulnerable age groups with the highest carcinogenic risks through exposure to atmospheric PM in Khulna city. Therefore, air pollution reduction plans and risk mitigation strategies should be developed and implemented by the government authorities. [ABSTRACT FROM AUTHOR]

False alarm resistant smoke detectors must pass the inflight smoke-detection certification test for implementation in aircraft. Inflight certification testing uses artificial smoke generators due to health and safety. Currently, there are no objective parameters to quantify an artificial smoke generator's aerosol production for certification testing. Therefore, this study's design was to create a framework for potential guidelines for standardizing an artificial smoke generator's aerosol production. Although the aerosols created by artificial smoke generators look like real smoke, there are inconsistencies between models that could create smoke detectors not activating during certification testing. Aerosols created by artificial smoke generators must be similar to smoke for many of the false alarm resistant smoke detectors to alarm. Therefore, verifying which artificial smoke generators produce an aerosol with similar particle characteristics to smoke is essential for the implementation of false alarm resistant detectors in aircraft. Furthermore, standardizing the artificial smoke generators for the total quantity of aerosol produced, rate of aerosol production, and repeatability of aerosol production and quantifying the effects of the ambient environment is necessary to ensure the reliability and integrity of the certification test. One possible result of a non-standard aerosol production during certification testing, specifically in regards to an unexpected overabundance of aerosol production, may cause the certification of smoke detection system that would not alarm the specified threat. Conversely, insufficient aerosol production during certification testing could create the requirement of a lower smoke detection threshold than intended, creating an unfair financial burden. This study found that artificial smoke generators produce an aerosol with similar particle size distributions and light scattering characteristics to smoke created by smoldering foam, smoldering wood, and lithium-ion battery thermal runaway vent-gas. Therefore, it is reasonable to conclude that aerosols from the tested artificial smoke generators are capable of alarming most false alarm resistant smoke detectors. Furthermore, there were measurable differences in the total quantity of aerosol produced and the rate of aerosol production between smoke generators used by four major airframe manufacturers for smoke-detection certification testing. In addition, changes in ambient temperature and pressure that may occur during a typical flight profile affected an individual smoke generator's production of aerosol. Sufficiently heating the smoke generator's mineral oil before aerosol production can mitigate the effects of varying ambient temperatures. [ABSTRACT FROM AUTHOR]

The application of immunomagnetic nanoparticles (IMNs) enables the isolation of rare circulating tumor cells (CTCs) from blood. Precise capture of CTCs with specific tumor phenotypes is achieved by attaching specific ligands to the surface of IMNs. The captured CTCs need to exhibit high bioactivity and proliferation ability for subsequent detection after co-culturing. The process of CTC enrichment using magnetic nanoparticles entails several issues, such as nonspecific capture and biological toxicity. Modifying the size of nanoparticles allows for altering the capture efficiency of nanoparticles for CTCs, as well as their biological activity and proliferation ability. In this study, two different sizes of magnetic nanoparticles are utilized to capture CTCs under diverse conditions. The capture efficiency of magnetic nanoparticles is assessed at different incubation times, along with determining the time needed to achieve and sustain the optimal capture efficiency. Fluorescence staining is employed to detect the bioactivity and cellular integrity of the captured CTCs. Subsequent to co-culturing with nanoparticles, the number of CTCs is measured every 24 h, and the survival rate is determined after 96 h. [ABSTRACT FROM AUTHOR]

A method is developed to produce large titanium monolithic burning particles with a diameter of 250–550 μm. The combustion of titanium particles in free fall in air is investigated. The characteristic times of the beginning of fragmentation, end of fragmentation, and end of burning as well as the laws of motion of particles (in particular, coordinate and velocity at the starting moment of fragmentation) are determined using video recording. The size of particles at which the fragmentation mode changes from "star" to "fir branch" is estimated. [ABSTRACT FROM AUTHOR]

The development of environmentally friendly materials based on natural and biodegradable sources, such as starch, represents an interesting alternative to attend to the environmental problems caused by excess waste from petroleum-based packaging. The use of emulsions to obtain edible films is a novel strategy to be explored to determine how formulation and constitution affect film properties. In such context, gelatinized tapioca starch (TS) and oregano essential oil (OEO) were used to produce new active edible films using casting technique and their physical and antimicrobial properties were studied. Regarding the emulsion constitution, which was obtained employing an high-speed homogenizer, exposure to ultrasound (US) and surfactant Tween 80 (T80) content, had relevant effects on micro (0.2 to 105 μm) and nanometric (63 to 212 nm) size distributions of the TS particles and the OEO droplets. Exposure to US reduced (4.8–34 μm) and stabilized microparticles but promoted nanoparticle aggregation during storage, independently of T80 addition. T80 helped to stabilize coarse emulsions showing a Sauter diameter of 21.4 μm along storage. Films from coarse emulsions containing OEO and T80 were stiffer (stress at break: 1.8 MPa), less soluble in water (≈ 35%) and yellowish than films without T80. In addition, surfactant promoted a discontinuous microstructure of the film matrix. Both films containing OEO showed a good capacity to inhibit the growth of spoilage microorganisms (≈ 2.5–4 log cycles reductions). Due to their performance as physical and antimicrobial barriers, the films can be proposed as active packaging alternatives to stabilize and release natural preservatives to promote food preservation during storage and as a tool to support environmental sustainability. [ABSTRACT FROM AUTHOR]

Municipal solid waste incineration (MSWI) fly ash is a collection of aggregates with different particle sizes, and the size distribution played an important role in its physicochemical and pollution characteristics. In this work, MSWI fly ash was divided into four size distributions (> 100 mesh, 100–200 mesh, 200–400 mesh, and < 400 mesh) with the negative pressure screen analyzer. The composition, structure, and morphology of MSWI fly ash, the total amounts, leaching toxicity, and chemical speciation distribution of heavy metals in MSWI fly ash varied with size distribution and was investigated. The results uncover that the phase composition of MSWI fly ash is almost the same regardless of size distribution, but the content varied. As the particle size decreases, the spherical particles of MSWI fly ash increase and its surface shape tends to be regular. There is no significant mathematical correlation between the leaching concentration or total amounts of heavy metals and size distribution of MSWI fly ash, but most heavy metals tend to deposit on fine particles. The residual and carbonate fractions form the main chemical speciation of heavy metals in MSWI fly ash, and carbonate states of high proportion facilitate the migration and leaching of heavy metals. This study highlights the importance of size distribution on enrichment of heavy metals on MSWI fly ash. And it also proposes that the influence of the incineration process, municipal wastes composition, and other factors on performances of MSWI fly ash remains to be clarified further. [ABSTRACT FROM AUTHOR]

This paper focuses on studying the microbiological properties of the Tibetan Palace Museum, which is located on the Qinghai-Tibet Plateau and contains a vast collection of cultural heritage artifacts. The air quality of the museum is critical to the preservation of these artifacts, and factors such as microbial species, concentration, and particle size distribution are important indicators of air quality. The paper examines the concentration levels, particle size distribution, species diversity, and correlation between environmental factors and microorganisms in the museum. The study found that the concentration of bacteria was 2–3 times higher than normal, while the concentration of fungi was lower than average. The predominant microorganisms in the museum were Bacillus cereus, Bacillus psychrodurans, and Neurospora terricola. The research also discovered that the concentration of microorganisms was positively correlated with PM2.5 concentration and negatively correlated with temperature, relative humidity, and PM10 concentration. The study concludes that the museum's micro-environment is not ideal for the preservation of ancient books and cultural relics, and more research is necessary to identify the general microbiological traits and eradicate hazardous species in plateau museums. [ABSTRACT FROM AUTHOR]

Extensive use of Al2O3 nanoparticles in consumer and industrial products has led to concerns about their potential environmental impacts in the recent years. In most studies concerning Al2O3 aggregation and disaggregation, more was to consider the single factor that influences their environmental behaviors. Understanding the combined abiotic factors that influence the fate, transport, and stability of nanoparticles in a complex aquatic system has become extremely important. Here, we reported and analyzed the major abiotic factors such as typical solution pH, electrolyte cations in different valences (Na+ and Ca2+), and the presence of humic acid (HA) that influence the stability, aggregation, and disaggregation behaviors of Al2O3 nanoparticles in a complex aquatic system. Dynamic light scattering technique combined with fluorescence spectroscopic analysis was used to explore the aggregation mechanisms. Experimental results indicated that Al2O3 nanoparticle stability was mainly controlled by the steric hindrance, van der Walls, and electrostatic interactions between HA and Al2O3 nanoparticles. Aggregation kinetics and attachment efficiency studies induced by the addition of Na+ and Ca2+ cations confirmed that divalent electrolytes could reduce the large energy barrier between the charged colloidal particles more efficiently, and induce a more aggressive aggregation of the particles. Additionally, the bridging effect of HA with Ca2+ was also an important mechanism for the aggregation enhancement, which had been confirmed by the fluorescence excitation-emission matrix (EEM) spectra analysis. These findings are useful in understanding the environmental challenges of inorganic colloidal particles in natural environments. [ABSTRACT FROM AUTHOR]

Data on microporosity (micropore size distribution) in the range from several angstroms to several nanometers, obtained by measuring the positron annihilation lifetime (PALS method) and by measuring CO2 sorption (low-temperature gas sorption, LTGS) are collated for a number of polymers with amorphous (polyetherimides, PEI) and semicrystalline (polyphenylene oxides, PPO) structures. The microporosity estimates based on the positron annihilation and CO2 sorption data are compared with published data obtained both experimentally and by the group contribution method for the permeability of these materials. The discrepancies found and their possible causes are discussed. [ABSTRACT FROM AUTHOR]

Seasonal atmospheric particulate matter samples with different particle sizes (< 2.5 μm [PM2.5], 2.5–5 μm [PM2.5–5], 5–10 μm [PM5–10], and 10–100 μm [PM10–100]) were collected to analyze the mass concentration and distribution characteristics of nine water-soluble ions (WSIs; F−, Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, and Ca2+) in Lvliang in China. The results of chemical composition analysis indicated that the average concentration of total WSIs was 29.08 µg·m−3 and accounted for 40.45% of PM2.5, 80.99% of which was attributable to SO42−, NH4+, and NO3−; the concentration demonstrated obvious distribution characteristics. NO3− and NH4+ primarily exist as NH4NO3 and (NH4)2SO4, respectively, in fine particles but as NaNO3 and NH4Cl, respectively, in coarse particles. The PM2.5 was alkaline overall, and K+ and NH4+ caused the highest RC/A values in autumn. Stationary sources contribute more to WSIs in particulates than mobile sources. The secondary transformation degree of SO2 was higher than that of NOx, especially in fine particles. The positive matrix factorization (PMF) and potential source contribution function (PSCF) models were combined to determine the sources of WSIs in PM2.5. Through use of the PMF model, five source factors were categorized: secondary aerosols (43.0%), biomass combustion (21.7%), coal combustion (17.6%), dust (10.9%), and vehicular traffic (6.8%). The results of the PSCF model suggested that the transport of pollutants from Shanxi, northwestern Shaanxi, Gansu, Inner Mongolia and Henan, had the greatest effect on air quality in Lvliang. [ABSTRACT FROM AUTHOR]

Precipitate-hardened high-entropy alloys (HEAs) exhibit great mechanical strength and exceptional ductility. However, the existing model fails to accurately predict the yield strength contributing from the solid solution strengthening and precipitate strengthening in the HEAs due to the neglect of the crucial roles including the complex chemical element, precipitate-size distribution, and the precipitate-spatial distribution. Moreover, a unified strength model for analyzing the yield strength in the HEAs is still lacking. A developed precipitate strengthening model considering the size distribution and spatial distribution is established and shows a higher accuracy compared to the existing model. The results show that the precipitate strengthening is the dominant contribution to the yield strength. It reveals that the effect of spatial distribution on precipitate strengthening is more pronounced than that of the precipitate-size distribution. This developed model provides a theoretical framework for determining the precipitate strengthening and the yield strength of HEA, and then subsequently guides the design of the high-strength HEAs. [ABSTRACT FROM AUTHOR]

Key message: In even-aged, monoculture eucalypt forest, symmetric inter-tree competition was far more important in determining tree growth rates than asymmetric competition. Tree size principally determined competitive ability at any time. In even-aged, monoculture forests, individual tree growth rates are much affected by the amount of the resources required for growth (particularly light, water and nutrients) that are available to them from the site on which they are growing. In turn, those amounts are much affected by competition for them between neighbouring trees. Competition may be 'symmetric', when tree growth rates are directly proportional to tree sizes, or 'asymmetric' when growth rates vary disproportionately with tree sizes. Using a large data set from blackbutt (Eucalyptus pilularis Smith) forests of sub-tropical eastern Australia, methods were devised to quantify the effects of symmetric and asymmetric competition; they were determined as the change each causes in individual tree growth rates over growth periods of a few years. It was found that symmetric competition was by far the principal determinant of tree growth rates. Asymmetric competition had much lesser effects, but was sufficient to alter substantially the development with age of the frequency distribution of tree sizes. It is concluded that the size of a tree at any time is the principal determinant of both its metabolic capabilities for growth and its competitive status and, hence, its growth rate. [ABSTRACT FROM AUTHOR]

With the implementation of sulfur emission regulations, influences of particulate matter (PM) emitted by marine diesel engines on nearshore atmospheric environment and human health are of increasingly concern. Whatever measures are chosen to meet sulfur emission regulations, the emission characteristic and influencing factors of PM should also be determined. In this study, number and mass emissions, volatility, main composition, and toxicity of PM from marine 4- and 2-stroke diesel engines were investigated. It was found that the size distribution curves of particle number are multiple peaks. Fuels and engines types influence the modal distribution of particles number concentration. For light diesel oil and low-sulfur heavy fuel oil (HFO), particle number was dominated by nucleation and accumulation mode respectively, and particle mass was dominated by accumulation mode. Reduction of fuel sulfur content (FSC) could reduce the particles mass, number and fraction of volatile substance emissions, and small-size particles had the most volatility. Particulate organic carbon (OC) was the main substance, especially for marine 2-stroke diesel engine burning HFO (high- or low-sulfur), while particulate OC contained a large number of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The PAHs also had very high toxicity when the engine was burning HFO. The use of low-sulfur HFO cannot make the marine diesel engine meet the current and upcoming PM regulations, and after-treatment technologies or cleaning fuel should be needed. [ABSTRACT FROM AUTHOR]

LED lights are widely used in household appliances, automotive lighting, decorative materials, and other fields due to their high energy efficiency. At the same time, LED waste is also growing rapidly. LED lamps contain some valuable elements, such as Ga and In, as well as some toxic and hazardous substances. Properly processing and recycling of LED lamps are significant for resources recovery and ecological protection. The particle size distribution, morphology, and elemental composition of the separated products of the LED light strip were analyzed. The results show that with the extension of the crushing time, the contents of Fe, Cu and C increased, while the contents of Si did not change significantly in the lamp bead powder. The contents of Cu, C and Si in magnetic materials decreased, more than 98% of the Fe entered the magnetic product following magnetic separation. Taking into considering the peeling off of the lamp bead powder and the distribution of elements in it, the optimal crushing time appears to be 9 s. The Ga-containing particles in − 0.074 mm were fully dissociated. The relative content of Ga and In in this particle size range reached 22.30% and 16.46%, respectively. In the thermogravimetric analysis of the LED lamp, the pyrolysis temperature was 400 °C, and the largest weightlessness peak was found to appear at 462 °C. The Mineralogy analysis provides a basic data for the recycling of waste LEDs, and a recycling process for waste LED is developed. [ABSTRACT FROM AUTHOR]

Recently, several experimental and theoretical studies have demonstrated the feasibility of enhancing the sonochemical production of hydrogen via methanol pyrolysis within acoustic cavitation bubbles (i.e. sonolysis of aqueous methanol solution). This review includes both the experimental and theoretical achievements in the field of hydrogen production by methanol sonolysis. Additionally, the limits of the process's applicability and plausible solutions are highlighted. The impact of different parameters influencing the process performance is discussed. Finally, the effects of methanol concentration on the size distribution of active cavitation bubbles are analyzed. [ABSTRACT FROM AUTHOR]

A mathematical simulation of the formation of the secondary liquid droplets as a result of the collision of their primary droplets has been performed by the VOF method. The influence of different factors on the conditions of fragmentation of liquid droplets and on their integral characteristics was investigated. The ratios between the surface areas of liquid droplets after and before their collision were calculated. It was established that the ratio between the surface areas of the liquid droplets of equal sizes is smaller than that of the liquid droplets having different sizes and that the centered collision of liquid droplets is most efficient. The critical Weber number of liquid droplets, an increase in which does not cause significant changes in the characteristics of their secondary droplets, was determined. [ABSTRACT FROM AUTHOR]

An electrical low-pressure impactor was used to measure the particulate matter (PM) characteristics in a formal e-waste recycling plant. The size distributions based on particle mass, number, and lung deposited surface area (LDSA) in different workshops were on-site detected and compared. The results show that PM emission characteristics were related to recycling processes and auxiliary activities. Coarse particles (PM10–2.5) possessed the main mass percentage in the workshops, and fine particles (PM2.5) mass constituted 27–46% of the PM10 mass. A unimodal distribution pattern was observed for the size distribution of LDSA values, and the peak value of LDSA at different sampling sites except TV-D workshop was observed at a diameter of 0.2 μm. When grouped by job tasks, TV dismantling and printed circuit board (PCB) heating had the highest PM pollution. The PCB heating process led to the continuous emission of fine particles, and the LDSA concentration was the highest (237 μm2/cm3). In addition, the usage of a forklift truck for material movement can cause fine particle emissions from diesel engine combustion. All the results can provide basic information for the characterization of PM emitted from various e-waste recycling processes, and for assessing the exposure risk of PM. [ABSTRACT FROM AUTHOR]

This work proposes a novel horizontal high-shear granulator for iron ore granulation before sintering process. The granulation behavior such as growth process and structure of granules were firstly analyzed, followed by the effects of operation conditions such as water content, initial particle size distribution, and the concentrate ratio. The results show that the granule size increased significantly with increasing the granulation time, and the structure of granule can be divided into three types: non-nuclei, single-nuclei, and multi-nuclei. Water promotes the coalescence and growth of particles, and a better granulation performance was obtained at the water content of 8.8wt% under the current raw material conditions. Increasing the nuclei particle ratio led to an increase in average size of granules and permeability of the granules bed, but a decrease in growth index. Besides, with increasing of concentrate ratio, granulation performance such as granule size, bed permeability, and uniformity became worse. [ABSTRACT FROM AUTHOR]

In order to discuss the particle size distribution characteristics in the roadside microenvironment. ELPI+ was used to collect size distribution data of atmospheric particles from four typical roadsides in downtown Tianjin, China. And the traffic flow data and meteorological data were monitored at the same time. It was found through statistical analysis that the number concentrations of PM1 and PM2.5 were 43,089 cm−3 and 43,268 cm−3, respectively. The particle number concentrations were much higher in winter. Besides, it decreased with the particle size. The particulate matter was dominated by nanoparticles (6–27 nm), accounting for 80.53% on average. The particle area, volume, and mass concentrations generally increased with the increase in particle size. For the four types of roads, the overall trends of particle size distribution were basically the same. And the particle number concentrations were higher at artery roads and outer ring road than at the other two roads. The correlation analysis results showed that the particle number and mass concentrations had negative correlations with traffic volume and vehicle speed. The meteorological parameters also affected the particle concentration levels. The particle size distribution was the result of combination effects of the nucleation, traffic emission, and secondary aerosol in the urban roadside microenvironment. [ABSTRACT FROM AUTHOR]

The study on the light absorption of carbonaceous components is a research hotspot in the field of aerosol optical. Size distribution and lensing effect have great influence on the absorption of elemental carbon (EC) and brown carbon (BrC). However, few studies were conducted on the spatial variations of BC and BrC absorption with different size ranges in different regions. In this study, the mass concentration, absorption coefficient and mass absorption efficiency (MAE) of size-resolved carbonaceous components in three functional areas of Nanjing were compared based on offline sampling and experimental analysis. Bimodal and unimodal size distributions were found for EC and BrC mass concentrations at the three sites, respectively. Affected by the emission of diesel vehicles and aggregation condensation, high EC concentration in the size range of 0.56–1 μm was found at the suburban site. Due to the secondary formation from VOCs, high BrC concentration in the size range of 0.18–0.32 μm was observed at the industrial site. High EC concentration in the size range of 0.18–0.32 μm caused by diesel emission was the main reason for the high EC absorption in the regional area. Compared with vehicle emissions, the absorption capacity of secondary BrC was weaker. The variation of MAE values caused by various sources was the key factor leading to BrC absorption, which varied greatly in different regions. This study is helpful to understand the variation of light absorption of carbonaceous component and its source influence in a typical polluted city in the Yangtze River Delta, which provides important data support for the comprehensive evaluation of the role of aerosol light absorption in the change of radiative forcing in different regions. [ABSTRACT FROM AUTHOR]

Printable conductive composites show potential in wearable electronic, capacitor, stretchable sensors, and conductors. Incorporating metal nanoparticles in composites is a leading method to achieve high performance. In this study, we present a method for preparing silver flakes with ultra-smooth surfaces and excellent electron transfer properties by combining a waterborne acrylic resin template method with an intensive energy ultrasonic technique. By varying the ultrasonic treatment time from 20 to 80 min, the size distribution of the silver flakes was controlled, ranging from 15.7 to 5.04 μm. Scanning electron microscopy results indicate that the intensive energy ultrasonic treatment does not affect the surface morphology of the silver flakes. Additionally, the electron transport difficulties arising from internal defects in silver flakes prepared by traditional methods have been mitigated. The influence of size distribution and filler content on the electrical conductivity of silver conductive composites has been investigated. The study identified a correlation between the particle size distribution of flake silver powder and the volume resistivity of the conductive composite material, wherein a reduction in particle size distribution leads to a corresponding decrease in volume resistivity. Furthermore, an increase in the filler content of the composite material was found to result in a reduction in its volume resistivity. Using flake silver powder with a median particle size (d0.5) of 5.38 μm as a representative sample, the volume resistivity was observed to increase from 8.50 × 10−5 Ω·cm to 8.63 × 10−3 Ω·cm as the silver content was decreased from 25 to 4 wt %. Concurrently, an examination of the conductive properties and the formation of the conductive network demonstrated alignment with the theoretical steady-state model.Silver flakes with ultra-smooth surface and excellent electron transfer property is prepared by combining vacuum-evaporated nanofilms method and intensive energy ultrasonic technique.Graphical Abstract: Printable conductive composites show potential in wearable electronic, capacitor, stretchable sensors, and conductors. Incorporating metal nanoparticles in composites is a leading method to achieve high performance. In this study, we present a method for preparing silver flakes with ultra-smooth surfaces and excellent electron transfer properties by combining a waterborne acrylic resin template method with an intensive energy ultrasonic technique. By varying the ultrasonic treatment time from 20 to 80 min, the size distribution of the silver flakes was controlled, ranging from 15.7 to 5.04 μm. Scanning electron microscopy results indicate that the intensive energy ultrasonic treatment does not affect the surface morphology of the silver flakes. Additionally, the electron transport difficulties arising from internal defects in silver flakes prepared by traditional methods have been mitigated. The influence of size distribution and filler content on the electrical conductivity of silver conductive composites has been investigated. The study identified a correlation between the particle size distribution of flake silver powder and the volume resistivity of the conductive composite material, wherein a reduction in particle size distribution leads to a corresponding decrease in volume resistivity. Furthermore, an increase in the filler content of the composite material was found to result in a reduction in its volume resistivity. Using flake silver powder with a median particle size (d0.5) of 5.38 μm as a representative sample, the volume resistivity was observed to increase from 8.50 × 10−5 Ω·cm to 8.63 × 10−3 Ω·cm as the silver content was decreased from 25 to 4 wt %. Concurrently, an examination of the conductive properties and the formation of the conductive network demonstrated alignment with the theoretical steady-state model.Silver flakes with ultra-smooth surface and excellent electron transfer property is prepared by combining vacuum-evaporated nanofilms method and intensive energy ultrasonic technique. [ABSTRACT FROM AUTHOR]

In this study, the electric spark discharge method was used to prepare a cuprous iodide nanocolloid (CuINC); specifically, an electrical discharge machine was used to prepare a CuINC under five sets of pulse width modulation (Ton–Toff) parameters, and ultraviolet–visible spectrophotometry and a zetasizer were used to evaluate the most suitable parameter set. Copper wires were used as electrodes (copper content = 99.7%, diameter = 1 mm), and deionized water mixed with iodine was used as the dielectric fluid. The analysis results indicated that the CuINC prepared under Ton–Toff = 10–10 µs had absorbance of 1.8 and a zeta potential of − 31.9 mV. The resultant CuINC had the highest concentration and suspension stability; this indicated that Ton–Toff = 10–10 µs is the most suitable parameter combination for preparing a CuINC. X-ray diffraction revealed a complete CuI crystal structure. Transmission electron microscopy images showed that most of the CuI nanoparticles were smaller than 5 nm and that the nanoparticles were evenly dispersed. The electric-discharge-based production process employed in this study is rapid and simple, and the end products have favorable suspension power. The method is a safe, environmentally friendly, and rapid method of preparing CuINCs. [ABSTRACT FROM AUTHOR]

We conducted impact experiments using targets composed of particles with size distributions and projectiles with a size larger than or comparable with the maximum size of particles in targets. The pattern and particle concentration in the ejecta curtain were investigated. The results show three types of ejecta curtain features: (i) filament pattern extending throughout the entire curtain and high concentration, (ii) filament pattern and low concentration, and (iii) mesh-like pattern with a structure on smaller scales than the entire curtain and low concentration. When the target consists of particles using a bimodal size distribution with size differences of more than one order of magnitude, the filament pattern appears, exhibiting case (i). If the target consists of particles with various sizes with size differences of more than one order of magnitude, the filament pattern appears, but the concentration decreases, appearing the features of case (ii). Case (iii) occurs when the target consists of particles with a single size or when the mass of particles with a certain size is dominant. Thus, the size distribution of the particles in the targets determines the pattern and particle concentration in the ejecta curtain. Based on these results, we confirm that the pattern in the ejecta curtain caused by the impact of the Small Carry-on Impactor (SCI) in the Hayabusa2 mission showing case (i) is consistent with the evaluated sizes and masses of grains and boulders in the ejecta curtain. [ABSTRACT FROM AUTHOR]

The particulate matter (PM) emitted by printers during printing pollute the indoor air, which can pose a health hazard for the people indoors. The source strength, decay characteristics, and mechanism of the PM emitted by printers were studied. A sealed chamber was used for printing experiments, and the particle number concentrations were monitored in real time using an Electrical Low-Pressure Impactor (ELPI+). Our findings highlight the negative impact of printing on the indoor environment. The printers directly emitted particles covering three size ranges: 15.8–94.5 nm, 94.5–313 nm, and 313–949 nm. The emission rates of PM0.1 and PM0.1-1 by the printers were 1.57×108–53.83×108/min and 3.46×108–143.81×108/min, respectively. The printer and the amount of toner used both affected the emission of particles, especially PM0.1-1. The particles emitted were mostly decayed within 1 h after printing; moreover, the decay of PM0.1-1 was slower than that of PM0.1. The decay rates of PM0.1 were 0.016–0.083/min in the 0–30 min period and approached 0 in the 30–60 min period. The decay rates of PM0.1-1 were 0.015–0.127/min within 60 min after printing and differed little across periods. One hour after printing, all but a very small proportion of particles measuring 54.5–94.5 nm was decayed in the chamber, indicating that particles of that size were decayed with greater difficulty. [ABSTRACT FROM AUTHOR]

We investigated the effects of sugar concentration on the electroporation, size distribution and average size of giant unilamellar vesicles (GUVs). GUVs were prepared from 40 mol% of 1,2-dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG) and 60 mol% of 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipids. Pulsed electric field was applied to the 40%DOPG/60%DOPC-GUVs and it induced lateral electric tension (σc) in the membranes of vesicles. The σc-induced probability of rupture (Ppore) and the rate constant of rupture (kp) of GUVs under the sugar concentration, c = 40, 100 and 300 mM, were determined. Both the Ppore and kp increased with the increase of σc, but higher tension was required to generate the same values of Ppore and kp with increasing c. We also investigated average sizes of GUVs from the size distribution of vesicles under various sugar concentrations. With the increase of c, the peak of the size distribution histograms shifted to the region of smaller vesicles. The average size decreased 1.6-fold when c increased from 10 to 300 mM. These investigations help to understand various biomedical, biophysical, and biochemical processes in vesicles and cells. Electroporation, size distribution and average size of charged GUVs were investigated under various sugar concentrations. The sugar concentration influences the electroporation of vesicles and the average size of GUVs. [ABSTRACT FROM AUTHOR]

Today air pollution caused by particulate matter (PM) is a global issue, especially in densely populated and high-traffic cities. The formation of reactive oxygen species (ROS) by various toxicological studies is considered as one of the important effects caused by airborne particles that can lead to adverse effects on human health. In this study, to answer the question of whether particle size affects oxidative potential (OP), we searched the main databases, including PubMed, Scopus, Embase, and Web of Science, and defined search strategy based on the MESH terms for the above-mentioned search engines. All articles published until 2021 were searched. An ANOVA was run using R software to show the correlation between the size distributions of particulate matter and oxidative potential (base on mass and volumetric units) in ambient air. As expected, the regression results showed that the relationship between particle size and OP values for the studies based on mass-logarithm has a significant difference in the different distribution size categories, which was related to the difference between the <2.5 and < 1 categories. However, ANOVA analysis did not show a significant difference in the volumetric OP logarithm in the different distribution size categories. In this study, it was found that sizes higher than 2.5 μm did not have much effect on human health, and it is recommended that future research focus on PM2.5. [ABSTRACT FROM AUTHOR]

DNA-binding protein from starved cells (Dps) takes a special place among dodecamer mini-ferritins. Its most important function is protection of bacterial genome from various types of destructive external factors via in cellulo Dps–DNA co-crystallization. This protective response results in the emergence of bacterial resistance to antibiotics and other drugs. The protective properties of Dps have attracted a significant attention of researchers. However, Dps has another equally important functional role. Being a ferritin-like protein, Dps acts as an iron depot and protects bacterial cells from the oxidative damage initiated by the excess of iron. Here we investigated formation of iron oxide nanoparticles in the internal cavity of the Dps dodecamer. We used anomalous small-angle X-ray scattering as the main research technique, which allows to examine the structure of metal-containing biological macromolecules and to analyze the size distribution of metal nanoparticles formed in them. The contributions of protein and metal components to total scattering were distinguished by varying the energy of the incident X-ray radiation near the edge of the metal atom absorption band (the K-band for iron). We examined Dps specimens containing 50, 500, and 2000 iron atoms per protein dodecamer. Analysis of the particle size distribution showed that, depending on the iron content in the solution, the size of the nanoparticles formed inside the protein molecule was 2 to 4 nm and the growth of metal nanoparticles was limited by the size of the protein inner cavity. We also found some amount of iron ions in the Dps surface layer. This layer is very important for the protein to perform its protective functions, since the surface-located N-terminal domains determine the nature of interactions between Dps and DNA. In general, the results obtained in this work can be useful for the next step in studying the Dps phenomenon, as well as in creating biocompatible and solution-stabilized metal nanoparticles. [ABSTRACT FROM AUTHOR]

Synthesis of useful products from waste material improves the process economy and sustainability. Cellulose nanocrystals (CNCs) have unique properties like nanoscale dimensions and excellent mechanical strength. CNCs can be synthesized from Banana pseudostem, the renewable agro-waste. In a two-step process for isolation of CNCs, chemically purified cellulose (CPC) was obtained from raw fibers and CNCs were isolated from CPC by acid hydrolysis method. The effect of chemical treatments on properties of prepared CNCs was investigated. The effect of hydrolysis reaction time on the morphology of cellulose nanocrystals was also studied. It was observed that partial lignin and hemicellulose with other extractives were removed during alkali treatment. FTIR analysis indicated that peaks at 1730 cm−1 and 1250 cm−1 only were present in the spectrum of raw fibers. It indicated the removal of lignin, hemicellulose, and waxes after pre-treatment. The spectrum for treated cellulose indicated that most of the lignin and hemicelluloses were washed out in alkali treatment. Rod-like nanocrystals with average length 500 nm and diameter 80 nm were observed from FE-SEM images. Increase in crystallinity with successive treatments, from raw fibers (18.2%) to CNCs (64.2%), was observed from XRD analysis. CNCs have lower thermal stability than the raw fibers as observed from thermogravimetric analysis. The percentage crystallinity was found to be 18.2% for raw fibers. The diffractogram of raw fibers also indicated increase in % crystallinity value upon alkali treatment (52.4%) and bleaching treatment (62.6%). The hydrodynamic size (Z average) of CNC was 140.3 nm. [ABSTRACT FROM AUTHOR]

Keeping horses in good condition requires providing them with living conditions that meet welfare requirements. These animals should be accommodated with suitable space, access to high nutritional fodder and water, and a suitable microclimate in their shelters. When it comes to the environment in the stables, a serious problem is created by particulate matter (PM), which consists of bacteria. PM concentration may be responsible for developing multiple lower respiratory tract diseases in horses, including allergies and recurrent airway obstruction (RAO). In turn, these ailments may lead to decreasing equine physical and mental fitness. Additionally, people who spend time in the stables are exposed to the same harmful factors. The study was conducted in Udórz Stud Farm located in the southern region of Poland. The study was carried out in 2 different types of stables: 3 runners (a type of stable where horses are housed together and occasionally linked up, e.g., for feeding or grooming) and 2 box stables. The research continued for 2 years and the samples were collected in each season. The bioaerosol samples were collected using a six-stage Andersen-Graseby cascade impactor to assess size distribution and concentrations of airborne bacteria. PM concentration was analyzed using the DustTrak™ II Aerosol Monitor 8530, while microclimate parameters were measured using the Kestrel 5000 Weather Meter. There are almost no studies concerning size distribution of airborne bacteria, individual PM fractions, and the impact of everyday handling on the changes in the bioaerosol and PM concentration. This preliminary study provided basic information on this subject. We have revealed a strong correlation between high PM and bacterial aerosol concentrations. Higher contamination levels were recorded in runners, as compared to box stables. The highest bacterial aerosol level was detected in the spring. The analysis of the fractions of the bacterial aerosol in the stables indicated the highest share of ultra-fine fraction (0.65–2.1 µm), while respirable fraction (below 4.7 µm) exceeded 75%. It was established that the concentration of the bacterial aerosol inside the stables was many times higher than outside. It depended significantly on everyday activities undertaken in the stables, like feeding or cleaning. Taking the above into account, a different cleaning system should be developed (a wet cleaning system, with the use of water) and excrement should be removed more frequently. [ABSTRACT FROM AUTHOR]

The Mössbauer effect (ME) spectroscopy is a powerful tool to obtain information about magnetic nanoparticles (NP). Here we correlate parameters that can be obtained from a ME spectrum (relative fractions of magnetite and maghemite and the volume dependent parameter λ = K V / k B T ) with other relevant quantities, such as DC saturation magnetization and X-ray diffraction NP mean diameter, D XRD . The study was performed on the decanted pellets of six different batches of NP obtained using the same synthesis procedure. It was observed that λ 1 / 3 presents a linear correlation with D XRD from which the effective anisotropy K for the entire ensemble of the batches could be calculated. The fraction of magnetite retrieved from ME spectra was well correlated to the saturation magnetization. In addition, it was observed that the magnetic response of the supernatant obtained after washing and centrifuging the synthesis product, decreases with λ , according to the fact that larger NP decant more easily during centrifugation. [ABSTRACT FROM AUTHOR]

Size-segregated aerosol particles were collected using a high volume MOUDI sampler at a coastal urban site in Xiamen Bay, China, from March 2018 to June 2020 to examine the seasonal characteristics of aerosol and water-soluble inorganic ions (WSIIs) and the dry deposition of nitrogen species. During the study period, the annual average concentrations of PM1, PM2.5, PM10, and TSP were 14.8 ± 5.6, 21.1 ± 9.0, 35.4 ± 14.2 μg m−3, and 45.2 ± 21.3 μg m−3, respectively. The seasonal variations of aerosol concentrations were impacted by the monsoon with the lowest value in summer and the higher values in other seasons. For WSIIs, the annual average concentrations were 6.3 ± 3.3, 2.1 ± 1.2, 3.3 ± 1.5, and 1.6 ± 0.8 μg m−3 in PM1, PM1-2.5, PM2.5–10, and PM>10, respectively. In addition, pronounced seasonal variations of WSIIs in PM1 and PM1-2.5 were observed, with the highest concentration in spring-winter and the lowest in summer. The size distribution showed that SO42−, NH4+ and K+ were consistently present in the submicron particles while Ca2+, Mg2+, Na+ and Cl− mainly accumulated in the size range of 2.5–10 μm, reflecting their different dominant sources. In spring, fall and winter, a bimodal distribution of NO3− was observed with one peak at 2.5–10 μm and another peak at 0.44–1 μm. In summer, however, the fine mode peak disappeared, likely due to the unfavorable conditions for the formation of NH4NO3. For NH4+ and SO42−, their dominant peak at 0.25–0.44 μm in summer and fall shifted to 0.44–1 μm in spring and winter. Although the concentration of NO3–N was lower than NH4–N, the dry deposition flux of NO3–N (35.77 ± 24.49 μmol N m−2 d−1) was much higher than that of NH4–N (10.95 ± 11.89 μmol N m−2 d−1), mainly due to the larger deposition velocities of NO3–N. The contribution of sea-salt particles to the total particulate inorganic N deposition was estimated to be 23.9—52.8%. Dry deposition of particulate inorganic N accounted for 0.95% of other terrestrial N influxes. The annual total N deposition can create a new productivity of 3.55 mgC m−2 d−1, accounting for 1.3–4.7% of the primary productivity in Xiamen Bay. In light of these results, atmospheric N deposition could have a significant influence on biogeochemistry cycle of nutrients with respect to projected increase of anthropogenic emissions from mobile sources in coastal region. [ABSTRACT FROM AUTHOR]

Thermal pretreatment by torrefaction is known to produce improved properties in biomass fuels, but the role of pellet size on key properties in commercially available hardwood derived fuel has not been investigated to date. In this study, densified Australian woody biomass was torrefied over different temperatures (250–300 °C), time (30 and 60 min) and mean pellet size (7 ± 0.5 mm and 15 ± 0.5 mm). Benchmarking, relative to raw fuel properties, is reported in terms of proximate analysis, high heating value (HHV) and water immersion tests as well as FTIR and thermal stability (TGA). Significant differences of 23.55% in mass loss (ML) and 10% in hygroscopic behaviour were observed at varied pellet size. FTIR analysis of the samples identified reduction of polar species such as the hydroxyl (-OH) functional group during torrefaction. This increased the hydrophobicity of torrefied pellets. Torrefaction of larger sized pellets was also accompanied with lower hemicellulose and cellulose degradation. A correlation predicted the HHV of the torrefied pellets which fits well with the actual HHV's of the wide body of literature with an average difference of less than 1 MJ/kg. Pellet sizing was found to impact the fuel properties only at milder torrefaction conditions. As such, with the increase in torrefaction severity, the effect of pellet size became insignificant. The outcomes emphasise the need to describe pellet size distributions when reporting torrefaction performance indicators, particularly if commercial scale torrefaction is used at higher temperatures and longer times. [ABSTRACT FROM AUTHOR]

Urban air pollution and exposure-related health impacts are being noticed and discussed very intensely in India. On the other hand, source-specific control is the primary focus for policymakers; however, diverse and complex sources make it difficult to immediately see the action and consequent impacts on better air quality. Many cities across the world have witnessed high air pollution levels at traffic junctions, more so in all Indian cities. Site-specific air pollution reduction can be a promising solution for managing the pollution level at highly polluted locations. CSIR-National Environmental Engineering Research Institute, India, has designed and developed Wind Augmentation and purifYing Unit (WAYU) to remove particulate and gaseous pollutants from urban hot spots such as traffic locations. In the present study, the authors attempted to evaluate the performance of two different designs of WAYU for the removal of particulate matters from polluted air at different traffic locations in Delhi City, the national capital territory of India. The performance analyses show that the current design of WAYU removes PM10 and PM2.5 concentrations in the range of 34–49% and 19–25%, respectively from the inlet air. The total PM collected from all WAYU devices was 34.19 kg from 120,557 operating hours' at all the sampling sites. The PM removal rate depends on the size-segregated particulate matter pollution load in the ambient air. [ABSTRACT FROM AUTHOR]

The present study examines the impact of urban attributes such as heterogeneous traffic, land use activities and meteorological factors on road dust resuspension and ambient particulate matter (PM) concentrations at urban roads. Silt load (SL) and PM emission rates from urban roads were quantified for 18 locations in Chennai and compared with 10 locations in Delhi city. Further, a detailed analysis was carried out for Chennai city alone to understand the size distribution of road dust, seasonal variation of SL, ambient PM concentrations and meteorological factors. Results indicated that the highest silt load values were observed on roads close to construction sites (Chennai = 34 g/m2 day and Delhi = 40 g/m2 day). Further, seasonal variation observations depicted that water stagnation on roads and poor drainage conditions during monsoon led to high silt load concentrations and subsequent PM emissions during post-monsoon season. Due to fugitive emissions and heavy-duty commercial vehicular (HCV) movement at construction sites, the 24-h average PM concentrations and total mass exposures (MET) were found to be highest compared to other locations (PM10 = 183.3 ± 25 μg/m3, PM2.5 = 80.7 ± 6.7 μg/m3 and MET = 2.66 μg/min). The PM2.5 and PM10 emission rates were also found to be higher at construction sites (PM2.5 = 6.65 and PM10 = 27.525 g/VKT) followed by the dumpsite (PM2.5 = 6.52 and PM10 = 26.96 g/VKT). The higher proportion of HCVs at dumpsite has led to higher PM emission rates. Further, the size distribution analysis of silt load showed that on average, 13–18% of dust deposited on roads is finer than 10 microns, 6–9% dust is finer than 2.5 microns and 4–6% of particulates is finer than 1 micron. The observations of the present study imply that traffic, land use and seasonality have a significant impact on road dust deposition and resuspension. [ABSTRACT FROM AUTHOR]

High-Si spheroidal graphite (SG) iron is a relatively new addition to the family of SG irons. While the industry has been successful in producing class 500-14 and 600-10 irons there is a paucity of published research data on the efficiency of inoculation on shrinkage and porosity reduction. The critical phase is the end of solidification when, as the amount of eutectic graphite generated decreases, graphite expansion may become insufficient to compensate the solidification shrinkage, increasing the risk of micro-shrinkage (microporosity) formation. The goal of this industrial research was to assess the efficiency of eight commercial inoculants in minimizing porosity occurrence in a 3.45%C, 3.75%Si SG iron. Metallographic analysis was conducted on the TA cups to evaluate the nodule count and size distribution. SEM analysis was used to study the type of nuclei, and tomography to quantify the amount of porosity in each TA cup. An attempt was made to correlate the graphite formation rate during eutectic solidification with the porosity level. Inoculants rich in Zr seem to produce the best results. [ABSTRACT FROM AUTHOR]

Exposure of microbial agents in the air of indoor dwellings is associated with effects on respiratory and general health. The current study was conducted in the urban area of Delhi Metropolis for the seasonal quantitative assessment of viable microbial indoor air quality. Bioaerosol measurement was conducted by using Anderson six stage impactor with cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 µm) throughout the all the seasons (April 2019 to March 2020). Meteorological parameters such as temperature and relative humidity were measured to check their effect on microbial survival. Air quality index data of the sampling area were recorded by DPCC air quality monitoring system, Ashok Vihar, Delhi. The highest (1654 ± 876.87 CFU/m3) and lowest (738 ± 443.59 CFU/m3) mean bacterial concentration in houses was recorded in August and December, respectively. Similarly, the highest fungal concentration (1275 ± 645.22 CFU/m3) was found in August and the lowest in (776 ± 462.46 CFU/m3) in January. Bacterial respirable fraction shows an irregular pattern in different seasons. In the case of fungi, the respirable fraction of 2.1 and 1.1 contributes more than 60% of total culturable bioaerosols in all seasons. Bacterial genera including Staphylococcus, Micrococcus, and Streptobacillus were most dominant, and Cladosporium, Aspergillus, Penicillium, and Alternaria were the most dominant fungal genera observed indoors. The results of this study suggest that higher respirable fungal fraction might penetrate deeper into the lungs and cause various health effects. A higher concentration of bioaerosols in outdoor areas than indoor shows that the source of indoor bioaerosols is outdoor air. [ABSTRACT FROM AUTHOR]

Purpose: The size was a key factor influencing the drug loading, release, and delivery efficacies of poly (lactic-co-glycolic) acid (PLGA) microspheres (MS). The purpose of the study was to explore a novel and simple method to prepare uniform-sized PLGA MS for drug delivery. Methods: Different from routine homogenizer, a vortex shaker was employed for emulsification during the preparation of PLGA MS. To enhance the homogeneity of resulted PLGA MS, a glass bead was used to facilitate the emulsification. The size of PLGA MS was controlled by adjusting the working frequency and time of vortex shaker. Then, selective centrifugation was used to further enrich PLGA MS of desired size. The resulted PLGA MS were systematically evaluated in anti-tubercular drug delivery. Results: Compared with the routine stirring-based method, the novel method possessed a higher efficiency of emulsification and resulted in more homogenous MS under similar conditions. The produced PLGA particles were of a narrow size distribution, which could be 1 to 5 μm by adjusting the working frequency and time of vortex shaker. The narrow size distribution made it rather easy to enrich PLGA MS of specific size through selective centrifugation. Then, to evaluate the potential of the PLGA MS for drug delivery, 2–3-μm sized PLGA MS were selected to deliver anti-tubercular drug rifampicin (RFP). In vitro experiments demonstrated that the loaded RFP could be well-controlled release and delivered into macrophages. Anti-tubercular experiments showed that the uniform-sized MS as carriers of RFP significantly enhanced the therapeutic efficacy of the drug. Conclusion: Collectively, the study provided a novel and simple method for preparing uniform-sized PLGA MS, which may be of potentially wide applications. [ABSTRACT FROM AUTHOR]

This paper studied on the microplastics (MPs) pollution in the surface water of the Songhua River in China. MPs were detected in all sampling sites of the river, the abundance of MPs ranged from 1.09 to 15.97 items/L, and the average abundance was 5.72 ± 4.02 items/L. Human interference had a significant impact on the abundance of MPs, and abundance in the downstream were higher than those in the upstream in the urban area along the Songhua River. In this study, MPs with size <0.5 mm and size [0.5,1) mm were the main sizes; fiber and debris were the most common types; yellow was the dominant color. MPs in the Songhua River might have similar sources and degradation experiences, because the size, type, and color had no significant difference (P>0.05) in different sampling sections. PE, PET, and PS were the most common polymers of MPs, accounting for 33.55%, 29.68%, and 18.71%, respectively. [ABSTRACT FROM AUTHOR]

The physicochemical properties of coal dust from fine filters in the degassing system of a Kuznetsk Basin mine are studied. The dust sample is investigated by atomic-emission spectroscopy, IR spectroscopy, dynamic light scattering, and thermal analysis. The dust undergoes technical analysis and granulometric analysis; the textural characteristics of its pore structure are analyzed by adsorption. Finally the change in chemical composition of the mineral components in the dust is expressed as a function of the particle size. [ABSTRACT FROM AUTHOR]

Caseins (αS1, αS2, β and κ) are the main protein fraction of bovine milk. Together with nanoclusters of amorphous calcium phosphate (CaP) and divalent cations, they combine to form a polydisperse distribution of particles called casein micelles. A casein micelle model is proposed which is consistent with the way in which intrinsically disordered proteins interact through predominantly polar, short, linear, motifs. Using the model, an expression is derived for the size distribution of casein micelles formed when caseins bind to the CaP nanoclusters and the complexes further associate with each other and the remaining mixture of free caseins. The result is a refined coat-core model in which the core is formed mainly by the nanocluster complexes and the coat is formed exclusively by the free caseins. Example calculations of the size distribution and surface composition of an average bovine milk are compared with experiment. The average size, size distribution and surface composition of the micelles is shown to depend on the affinity of the nanocluster complexes for each other in competition with their affinity for free caseins, and on the concentrations of free caseins, calcium ions and other salts in the continuous phase. [ABSTRACT FROM AUTHOR]

The study describes an analytical model of laser beam scattering on an inhomogeneous ensemble of erythrocytes. The model takes into account erythrocyte variation in size, shape, and spatial orientation. A relationship is established between an experimentally determined parameter: visibility of the diffraction pattern, and a characteristic serving as a measure of inhomogeneity of erythrocyte size and shape in a blood specimen. This relationship is shown to be monotonous, which means that erythrocyte variation in size and shape can be assessed based on measurements of the diffraction pattern visibility. [ABSTRACT FROM AUTHOR]

The present study was carried out to estimate the spatiotemporal variation of fungal bioaerosols, in and around a landfill site in Delhi. The sites were deep in the landfill to nearby residential areas. Fungal bioaerosol sampling was done with the help of Anderson six stage viable cascade impactor on monthly basis for one year from June 2015 to May 2016 at seven different sites in and around the landfill site. The entire sampling period was classified in five different seasons, viz., winter, spring, summer, monsoon and autumn, characteristic of Delhi. It was observed in monsoon season concentration was maximum at most of the sites while lowest during autumn season. Contrary to this, it was also found that concentrations of fine fraction of bioaerosols were significantly high even during autumn at sites deep in the landfill while low in the residential areas near landfill. As such no significant pattern was observed with the coarse fraction of fungal bioaerosols. Typical relations of fungal concentration with the meteorological parameters were also observed. It was noticed that concentration was directly related to temperature and wind speed while inversely related to humidity. Fine and coarse fractions of bioaerosols showed a very good and positive relationship with each other. Among the eight fungal genera identified from the samples of Okhla landfill sites, Penicillium, Aspergillus and Rhizopus were found in abundance at all the seven sites in all the five seasons. Alternaria and Fusarium were found in abundance in spring, summer and winter seasons whereas Cladosporium in autumn and winter. Aspergillussps was present in all the five seasons. [ABSTRACT FROM AUTHOR]

Size-fractionated samples were collected at five coastal urban sites in Fujian Province, southeast China, in 2016 and 2017 to determine the trace elements using ICP-MS. Ca, Fe, Al, Mg, and K were the most abundant elements among the studied elements in TSP, much higher than those of heavy metals. The annual mean concentrations of Pb, As, V, Ni, Cd, and Mn were within the acceptable limits of the World Health Organization and the Ministry of Ecology and Environment of China while Cr(VI) exceeded the limits. Most elements exhibited clear seasonal patterns with maxima over the cold season and minima over the warm season. The spatial variabilities in concentrations of the measured elements were not significant except Ni and V. However, the size distribution pattern of each element was quite similar across the region. Characteristic size distributions of elements allowed identification of three main groups: (a) unimodal distribution in the coarse fraction for Ca, Al, Mg, and Ba; (b) unimodal distribution in the fine fraction for Pb, Se, As, Ag, V, Ni, Zn, and Cd; and (c) bimodal or multimodal distribution for Fe, Mn, Cr, K, and Cu. The combination of the size-fractionated concentrations, enrichment factors, correlation coefficients, and factor analysis offered the identification of mixed sources such as vehicular exhaust and wear, heavy fuel oil combustion, and resuspension of road dust. Non-carcinogenic health risks associated with inhalable exposure to airborne metals were higher than the safety threshold (hazard index > 1) across the region, suggesting non-carcinogenic health risks via inhalation. Mn, V, and Ni contributed 74–83% of the total non-carcinogenic risk. The assessment investigation of carcinogenic health risks revealed V and Cr(VI) as elements with the largest carcinogenic risks, accounting for more than 95% of the overall inhalation risk. Nevertheless, the carcinogenic risks for children and adults were between 10−6 and 10−4, within the range considered acceptable by the US EPA. In terms of the size-fractionated risk, PM2.5 contributed 43–50% and 39–44% of the total non-carcinogenic and carcinogenic risks, respectively, indicating the potential health hazard of coarse particle–bound toxic metals was not negligible. [ABSTRACT FROM AUTHOR]