Size Distribution Of Elements Research Articles

Direct Recycling of LixNi0.5Mn0.3Co0.2O2 from Production Scrap and End‐Of‐Life Batteries, Using Solid‐State Relithiation

AbstractDirect recycling of Li‐ion battery cathodes offers a sustainable and potentially cost‐effective alternative to conventional methods, often involving complex chemical processes and significant material losses. This study focuses on the relithiation of cathode materials from quality control reject (QCR) and end‐of‐life (EoL) Li‐ion cells to restore their physical structure, morphology, and electrochemical performance. Two NMC532/graphite pouch cells from the same manufacturer were studied. QCR cells, stored under ambient conditions, experienced corrosion and degradation before recycling, while EoL cells were cycled to the end of life. The cells were disassembled, and the cathode materials were delaminated using NaOH solution, then relithiated with LiOH at 700 °C for 15 hours in the air. Extensive characterization analyzed elemental composition, structural properties, thermal stability, and particle size distribution. Results indicated that relithiation successfully restored lithium content and improved the structural ordering and morphology of the cathode materials. The electrochemical performance of the relithiated cathodes exhibited good stability over 100 charge‐discharge cycles. The relithiated QCR samples achieved a capacity of 155.57 mAh g−1, while EoL samples reached 152.53 mAh g−1, comparable to pristine materials. This study highlights relithiation's potential to extend the lifecycle of Li‐ion cathodes, contributing to a more sustainable circular economy for battery materials.

Gas and particle emissions from rifle and pistol firing

Emissions were sampled from firing an M4 carbine rifle and a M9 (military issue of Beretta 75 FS 9 mm pistol) to develop sampling methods and assess potential exposures and range contamination issues. Breech and muzzle emissions were sampled from the rifle when firing M855A1 ammunition (lead (Pb)-free slugs) in single- and triple-shot burst mode and from single pistol shots when firing 9 mm XM1152 ammunition (not Pb-free). Emissions were sampled for carbon monoxide (CO), carbon dioxide (CO2), methane, hydrogen cyanide, ammonia, particulate matter by size, polycylic aromatic hydrocarbons, and volatile organics. Analyses on the particles included elemental composition, size distribution, carbon composition (black, total, organic, and elemental carbon), and particle composition and morphology. Emission concentrations from both the rifle and pistol were characterized by CO/CO2 ratios between, approximately, 1/1 and 2/1, respectfully, indicating incomplete carbon oxidation. The initial particle size distribution was dominated in number by particles smaller than 40 nm but the high particle concentrations led to rapid agglomeration. The abundance of CO and metals of inhalable particle size are noteworthy and indicate that further assessment of exposure would determine potential inhalation health hazards, particularly in indoor firing ranges.

Characterisation of urban aerosol size distribution by radiocarbon and PIXE analyses in a middle-European urban environment for source identification: a pilot study

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.

Source Apportionment of Particulate Matter in a Metal Workshop.

Metal workshops are workplaces with the substantial production of particulate matter (PM) with high metal content, which poses a significant health risk to workers. The PM produced by different metal processing techniques differs considerably in its elemental composition and size distribution and therefore poses different health risks. In some previous studies, the pollution sources were isolated under controlled conditions, while, in this study, we present a valuable alternative to characterize the pollution sources that can be applied to real working environments. Fine PM was sampled in five units (partially specializing in different techniques) of the same workshop. A total of 53 samples were collected with a temporal resolution of 30 min and 1 h. The mass concentrations were determined gravimetrically, and the elemental analysis, in which the concentrations of 14 elements were determined, was carried out using the X-ray fluorescence technique. Five sources of pollution were identified: background, steel grinding, metal active gas welding, tungsten inert gas welding, and machining. The sources were identified by positive matrix factorization, a statistical method for source apportionment. The identified sources corresponded well with the work activities in the workshop and with the actual sources described in previous studies. It is shown that positive matrix factorization can be a valuable tool for the identification and characterization of indoor sources.

Morphometric and soil texture analysis of soil material from wasp nests Sceliphron destillatorium (Illiger, 1807) (Apoidea: Sphecidae)

Background. The article presents the data obtained as a result of our research on the nests of an aboriginal wasp species on the territory of Ukraine – Sceliphron destillatorium (Illiger, 1807) that belongs to the family Sphecidae. We collected 54 wasp nests in different regions: Zakarpattia (n = 4), Ivano-Frankivsk (n = 1), Rivne (n = 12) and Lviv (n = 35) Regions. The data are presented as a result of measuring the main morphometric parame­ters of nests (length, width of cells and mass of nests) which are typical of the species under study. The paper also reports the results of the soil texture analysis of the soil material of twelve wasp nests from four different places of “mass nesting” and compares the results with the control samples of the surrounding soils in the corresponding areas. The study aimed at investigating the structure of the nests of S. destillatorium wasps, determining the soil texture of the soil material of nests from different regions of Ukraine and comparing them. Material and Methods. The nests of Sceliphron destillatorium wasps were the object of the study. The morphometric parameters of nests were measured with an automatic digital caliper 0–150 mm and Axis A500 technical chemical scales. The soil texture analysis was performed by the pipette method. The potentiometric method was used to determine the pH of the soil material. In addition, the determination of the CO2 carbonates was carried out according to the volumetric method. Results. We have analysed 54 nests of S. destillatorium. 46 nests were found in “mass nesting places” (in some places several samples were found): in Lviv (3 sites) and Rivne Regions (1 site – Rivne Nature Reserve). The content of granulometric elements was determined in twelve wasp nests from these places and twelve control soil samples were taken around the places of “mass nesting” (three samples of surrounding soil from each location). In order to compare the particle size distribution of elements in all analysed samples (24), we drew cumulative curves and determined coefficients of uniformity and curvature. Conclusions. Nest weighing revealed considerable variations in the mass of the nests – from 10.06 to 222.56 g – depending on the number of cells in a nest. The size of the nests also varied. The number of cells in the nests varied from 2 to 37 (mean = 13; n = 54 nests). As a result of the soil texture analysis of the nest soil material, we determined the percentage of granulometric elements used by the wasps for the construction of their nests. It was found that fine sand was one of the predominant fractions in all twelve nests. The similar content of all five fractions of soil material of wasp nests from different areas indicates that the soil texture of the nests which were built by S. destillatorium probably does not depend on their geographical location.

Integrating Simulation and Experimentation for Optimized Compaction Powder Forming: A Study on RVE Size, Friction, and Particle Size Distribution

This work comprehensively represents multi-particle finite element simulations for powder compaction, including examining representative volume element (RVE) size, friction effects, and particle distribution. The analysis provides valuable insights into the correlation between RVE size and relative density, facilitating a comprehensive understanding of the sensitivity of process parameters to relative density. Furthermore, the research investigates the impact of particle size distribution. Moreover, the study investigates the influence of friction between powder particles and the die wall. Results demonstrate that increased friction leads to a significant reduction in relative density.

Considering the Size Distribution of Elements in Particle Matter and Oxidation Potential: Association before and after Respiratory Exposure

Oxidation potential (OP), reflecting the redox activities of particle matter (PM), is considered an optimal measure to explain the biological effects of PM exposure. However, the size resolution of the relationship between OP and chemical composition in PM, especially how the relationship changes after respiratory exposure, has not been well investigated. In this study, size-resolved indoor PM10 samples were collected from a waste recycling plant from November to December 2021 using an Anderson eight-stage cascade impactor. OP, measured by a dithiothreitol (DTT) assay (defined as OPDTT), and elements, determined by inductively coupled plasma–mass spectrometry (ICP-MS) in size-resolved PM, were determined to check their relationships and the related human exposure risk. The results indicated that compared with PM0.4 and PM0.4–2.1, PM2.1–10 contributed the most to total OPDTT and its bound elements contributed the most to potential health risks, both before and after respiratory exposure. The association between OPDTT and the elements varied with PM size. Pearson correlation analysis showed that the PM0.4- and PM0.4–2.1-bound elements were moderate-to-strongly positively correlated with OPvDTT (r: 0.60–0.90). No significant correlation or dose–response relationship was found in PM2.1–10. After respiratory exposure, several PM0.4- and PM0.4–2.1-bound elements had a moderate-to-strongly positive correlation with deposition fluxes of OP (defined as OPFlux) (0.69–0.90). A generalized linear model analysis showed that the interquartile range (IQR) increase in the PM-bound elements (ng h−1) was associated with a 41.7–58.1% increase in OPFlux. Our study is a special case that enriches the knowledge of the association between OPDTT and the chemical composition of PM of different sizes, especially after respiratory exposure, but the generalizability of the findings to other settings or types of PM may be limited. The associations among OPDTT, other chemical compositions of PM, and human exposure risk merit further research.

Size distribution and source-specific risks of atmospheric elements in Dalian, a coastal city in north China

Trace elements in particles play an essential role in particle-related health and environmental effects and were recognized as primary source tracers. An understanding of the size-segregated elemental composition is critical for accurate source attribution and risk evaluation. The present study investigated the characteristics of 28 elements in the size-fractioned particles of a coastal megacity in north China. The size distribution of element concentration posed bimodal peak mode, and the proportion of most trace elements tended to increase with the decreasing particle size, especially toxic metals like Hg, Ga, Tl, As, Pb, Se, and Cd. Source attribution based on the size-segregated concentrations was conducted by positive matrix factorization. Natural sources such as crust and sea spray aerosol dominated the trace element concentration in the large particles, while anthropogenic sources such as traffic, biomass, coal combustion, and industry contributed the majority in the fine particles. The source-specific exposure risk calculation based on the size-segregated dataset showed a noncarcinogenic risk (HQ) of 6.62 for children, mainly contributed by Tl and As from biomass burning, petrochemical refining, and coal combustion. Compared with larger particles, the finer particles generated a higher HQ and carcinogenic risk, especially particles smaller than 0.49 μm. Fine particles primarily emitted from the petrochemical industry and coal combustion brought out the largest HQ, while fine particles from vehicle traffic and the petrochemical industry contributed the largest carcinogenic risk. Transport of sea spray aerosol contributed a considerable amount of the carcinogenic risk in the coastal urban area.

Combustion aerosols and suspended dust with controlled processes in Lhasa: Elemental analysis and size distribution characteristics

To explore air contamination resulting from special biomass combustion and suspended dust in Lhasa, the present study focused on the size distribution and chemical characteristics of particulate matter (PM) emission resulting from 7 types of non-fossil pollution sources. We investigated the concentration and size distribution of trace elements from 7 pollution sources collected in Lhasa. Combining Lhasa's atmospheric particulate matter data, enrichment factors (EFs) have been calculated to examine the potential impact of those pollution sources on the atmosphere quality of Lhasa. The highest mass concentration of total elements of biomass combustion appeared at PM0.4, and the second highest concentration existed in the size fraction 0.4–1 µm; the higher proportion (12 %) of toxic metals was produced by biomass combustion. The elemental composition of suspended dust and atmospheric particulate matter was close (except for As and Cd); the highest concentration of elements was all noted in PM2.5-10 (PM3-10). Potassium was found to be one of the main biomass markers. The proportion of Cu in suspended dust is significantly lower than that of atmospheric particulate matter (0.53 % and 3.75 %), which indicates that there are other anthropogenic sources. The EFs analysis showed that the Cr, Cu, Zn, and Pb produced by biomass combustion were highly enriched (EFs > 100) in all particle sizes. The EFs of most trace elements increased with decreasing particle size, indicating the greater influence of humanfactors on smaller particles.

Physicochemical characteristics of atmospheric particles in south western (Pune) region of India: Elemental size distribution, source analysis and risk assessment

Chemical characteristics of size-resolved particulate matter (PM) and bound elemental species were investigated under an intensive measurement campaign during winter of 2021 in urban dwelling of south western (Pune) region of India. During the study period, average mass concentrations of PM10, PM4, PM2.5 and PM1 were 182.4 ± 48.7 μgm−3, 76.2 ± 26.2 μgm−3, 63.5 ± 22.4 μgm−3, 17.7 ± 6.9 μgm−3 respectively. Diurnal variability indicated significant high concentration during night and early morning hours attributed to the high volume of heavy-duty vehicles. Bimodal distributions of PM mass concentrations in coarse fraction (Mass Median Aerodynamic Diameter (MMAD) ± Geometric Standard Deviation (GSD) = 4.32 ± 1.27) was noted while accumulation of elements was found higher in fine(0.43–2.1 μm) > coarse(2.1–5.8 μm) > large mode(5.8–10 μm) particles. As per size distribution characteristics, Mn, Pb, Cu, Sn, Zn, Mo were concentrated in coarse mode; As, Cr, Fe, Ni was concentrated in both large and coarse mode while Al, Si depicted multimodal distribution across coarse and fine range. High MMAD (≥1.8) and GSD (>1.2) of all elements pointed towards significance of coarse particles in this study region. Ni and Cr (VI) via inhalation exposure pathway pose highest hazard quotient (HQ) and excess lifetime cancer risk (ELCR) respectively within respirable size range(2.1–3.3 μm) while children were subject to potential health risk than adults mainly through ingestion mode of exposure. Principal Component Analysis (PCA) suggested crustal origin, resuspended road dust along with vehicular traffic and industrial emissions as major sources.

Size-fractionated ambient particulate matter induce toxicity: Oxidative potential, cytotoxic effect and inflammatory potential

Present study highlighted the importance of examining the toxicological profile of size-segregated particulate matter (PM) bound metals (Fe, Mn, Ni, Pb, Zn, Cu, Cr, Co, Cd) at urban site of Pune city, India. The total aerosol mass was composed of 61.2% and 38% fine and coarse particles, respectively with maximum distribution observed in 4.7–2.1 μm size mode. Elemental size distributions indicated the prime association of Fe, Mn and Zn with coarse sized PM, while remaining metals were predominantly associated with fine PM. Seasonal mass and elemental distribution profile of size-resolved PM was characterized with maximum concentration found in winter season. Enrichment factor analysis revealed the contribution of anthropogenic emissions to Co and Ni in fine mode while less enriched metals, Fe and Mn were allied with crustal and natural sources. Oxidative potential of particles in terms of Dithiothreitol (DTT) loss was found to be maximum in the size range of 4.7–1.1 μm with dominant contribution of PM bound metals (Fe, Cu, Cr, Mn, Ni, Pb, and Zn). On exposure to PM samples, prominent enhancement in the expression of cytokines (especially TNFα) as compared to the control has confirmed their inflammatory nature. Incubation of A549 cells with PM suspension (75 mg/ml) caused pronounced reduction (p < 0.01) in cell viability with significant morphological changes, associated with cell death. Respiratory deposition doses of PM in head region were found to be more impacted by coarse sized particles while contribution of fine PM was dominant in alveolar and tracheobronchial region, signifying serious health risks to the exposed population. In addition to the basic knowledge of toxicity mechanisms associated with size fractionated PM, these results together with the analysis of correlation between PM bound metals and biological assays will be relevant to better characterize the potential health risks and possible future mitigation strategies.

Different metal precursor based rapid synthesis of α-Ni(OH)2-type Ni-Co-Mn layered double hydroxides and its use as electrodes for high performance energy storage devices

Improvement in the specific capacity of battery type electrode material is vital for creating hybrid devices with superior electrochemical performance. To accomplish this, mixed metal hydroxides, Ni0.7Co0.2Mn0.1(OH)2, are synthesized via a simple co-precipitation method by rapid pH switching using chloride, nitrate, acetate and sulphate salts of Ni, Co and Mn. P-XRD analysis confirmed the formation of pure and highly crystalline materials stabilized in the α-Ni(OH)2 structure. Finely divided particle type microstructure with sub 100 nm size and homogenous distribution of elements are confirmed by FESEM and EDX analysis, respectively. Among the studied samples, the layered hydroxide synthesized using chloride salts (Ni0.7Co0.2Mn0.1 LDH-Cl) shows the highest specific surface area of 58.8 m2 g−1 and pore volume of 0.083 cc g−1. The compound exhibited a high specific capacity of 978 C g−1 at 1 A g−1. The observed capacity is much higher than all other double hydroxides studied here and those we have come across in the literature reports on similar metal hydroxides. The diffusion dominance (b = 0.55) and quantitative separation of diffusion and capacitive capacity at different scan rates for Ni0.7Co0.2Mn0.1 LDH-Cl is also studied by CV analysis. Nyquist plot equivalent circuit fitting shows low charge transfer resistance (Rct = 17.6 Ω) and Warburg impedance (Zw = 35 Ω) for Ni0.7Co0.2Mn0.1 LDH-Cl. The high-capacity retention of 90 % for 5000 CV cycles at 100 mV sec−1 and 99 % for 1000 GCD cycles at 5 A g−1 for Ni0.7Co0.2Mn0.1 LDH-Cl confirm its potential for use as a battery type electrode material for practical applications.

Pollutant characteristics and size distribution of trace elements during stormwater runoff events

Priority trace elements As, Cu, Cr, Ni, Pb, and Zn are largely present in urban stormwaters and should be controlled due to their impact on water bodies. As it has been observed that there are numerous limitations in the purification performance of roadway stormwater runoff treatment systems, the particulate size distribution of trace elements was studied extensively to assess the colloidal fractions present in stormwater runoff of a high-traffic roadway site (100 000 vehicles/day). Besides the evaluation of the total Event Mean Concentrations (EMCs) and dissolved concentrations, a complete fractionation scheme of low settling phase of runoff water (<30 µm) was applied to a series of rain events, considering 8 µm and 5 kDa, as relevant cut-offs between particulate/colloidal elements, and colloidal/truly dissolved elements. The intra-event size distribution was also considered to assess the first-flush effect and the variation of the physical speciation. The high-level traffic associated with climatic conditions (rainfall depth) are responsible for very high EMCs for Zn and Cu, together with a significant exceedance of the European environmental water standards (<0.45 µm concentrations). Ni, Cr and Pb are mainly present as particulate and colloidal metals. Therefore, considering a more complete size distribution is relevant for these elements. For As, Cu and Zn, the conventional fractionation at 0.45 µm seems to be sufficient to evaluate the highly mobile fraction. The results also indicate that, while the main particulate load may be collected within the early volumes of the rainfall events (about 30%), the variability of rain intensity during long events induces changes in particulate and colloidal metals in the runoff. The treatment of runoff must then be considered as a whole in view of the variability of trace metal size distribution. This suggests that urban stormwater runoff treatment systems which employ only the settleable fraction are not sufficient to limit the chemical and ecological risks to receiving water bodies.

The Study of Modification of PVC-materials by Rice Husk Ash Including Activated by Cationic Surfactant and Wollastonite on Its Basis

This article examines the use of waste rice processing as a promising fillers for PVC finishing materials. Due to the presence of amorphous silicon dioxide these fillers improve the performance properties of filled PVC, while lignin and cellulose in their composition accelerate biodegradation when buried in the soil. The use of these wastes allows solving the problems of “green” chemistry and closed-cycle economy and reducing the cost of finished polymer products. The paper studies the effect of ash of rice husk and synthetic wollastonite on its basis on the diffusion processes occurring during mixing of PVC and plasticizer. Activation of the RHA surface by CATAPAV significantly affects its elemental and particle size distribution and structure porosity, leading to a decrease in the porosity of the filler, reducing its particle size and narrowing the distribution of particles and pores in size. At use of silicate fillers of optimum composition growth of tensile strength, thermal stability and decrease of plasticizer migration from PVC compositions, owing to plasticizer retention in pores of these fillers is reached.

Investigation of reducing trace elements and PM emission from coal combustion by blending coal

The fine particles and their associated trace elements derived from coal combustion had a severe adverse effect on the environment or human health. In this paper, HLH (lignite) and HS (bituminous) were blended under the predetermined ratio, and the blended coal was burned in a drop tube furnace (DTF). The particle size distribution (PSD) of particulate matter (PM) and trace elements (As, Se, Pb and Cd) were investigated during the blending coal combustion. The experimental results demonstrated that the mass concentration of PM from HLH coal combustion was higher than that of HS coal, which was attributed to the thermal instability of the minerals in HLH (lignite). In addition, it was found that PSD of PM was not consistent with that of trace elements. The blending coal combustion not only suppresses PM formation, but also reduces As, Se, Pb and Cd emission due to lowering ash fusion temperature of blending coal and liquidus capture of fine particles. Compared with the calculated values, the mass concentration of PM0.2–0.5, PM0.5–1.0, PM1.0–2.5 and PM2.5–10 from HS1HLH1 (the mass ratio of HS/HLH was 1.0) combustion was reduced by 6.06 %, 45.02 %, 50.17 % and 55.59 %, respectively. At the same time, the reduction efficiency of As, Se, Pb, and Cd emission concentration in PM0.2–0.5 by HS1HLH3 were the highest (about 91.7 %, 71.06 %, 83.45 % and 73.50 %), and their emission concentration was 0.16, 0.95, 0.97 and 0.02 μg/m3. While HS1HLH1 was the most effective for reducing As, Se, Pb, and Cd emission in PM0.5–10. Lastly, above 50 % As, Pb and Cd in PM10 was existed as the mobile phase during raw coal combustion, which had a harmfulness for the environment or human being. HS1HLH1 could stabilize Se, Pb, and Cd, and their residual fraction in PM10 were 59.4 %, 49.1 % and 29.2 %, respectively.

Impacts of Nano SiO2 Addition on the Formation of Ultrafine Particulate Matter during Coal Combustion

Clay minerals composed of Si and Al could help reduce ultrafine particulate matter (PM) formation as an additive during coal combustion while currently unacceptable high adding dosages (normally 3–5 wt.%) are required due to their inadequate capture efficiency. To find additives that could effectively reduce the formation of ultrafine PM, coal combustion with a novel nano SiO2 additive (&lt;100 nm) was performed to evaluate its effects on reducing ultrafine PM. The generated PM10 was sampled to characterize their particle size distribution, mass yield, size-resolved composition and micromorphology. The results showed that adding a small dosage (0.6%) of nano SiO2 reduced the mass yield of ultrafine PM by 30.70%, showing a much higher ultrafine PM capture efficiency than an existing micron-sized natural clay mineral. However, its performance on different coals varied due to disparities in ash content and composition in coal. A composition analysis revealed that the Na content in the ultrafine PM was decreased after adding nano SiO2, indicating that nano SiO2 inhibited the migration of volatile alkali metals such as Na into ultrafine PM because the Na-containing mineral vapor reacted with the nano SiO2 additive particles with a large specific surface area at a high temperature and inhibited their transformation into ultrafine PM via homogenous nucleation. Changes in the element size distributions and micromorphology showed that the majority of the added nano SiO2 particles reacted or coalesced with each other and/or the minerals embedded in coal, finally growing into a larger PM.

Experimental study on PM10 formation characteristics of co-combustion with pulverized coal and sludge

At present, the output of municipal sludge in China is increasing year by year, and co-combustion of sludge and pulverized coal for power generation is a means to treat sludge in large quantities. However, the co-combustion of sludge and pulverized coal will generate a lot of particulate matter (PM). In this paper, the formation characteristics of particulate matter (PM10) produced by the co-combustion of sludge and pulverized coal were studied. The effect of the furnace temperature and the sludge mixing ratio on the mass-based particle size distribution and elemental composition of PM10 in sludge, coal combustion and co-combustion was discussed. The experiment results show that the mass-based particle size distribution of PM10 produced by pulverized coal and sludge combustion are both bimodal, while the elemental composition and particle size distribution of PM10 are different. Whether burning alone or co-firing, increasing the furnace temperature will increase the mass yield of PM10. Increasing the temperature promotes particle fragmentation more than the melting aggregation of particulate minerals, increasing PM0.4–10 yield. The mass yield of PM10 produced by coal combustion is higher than that of sludge. In the sludge addition ratio range ≤ 30%, increasing the sludge addition ratio will reduce the mass yield of PM10. The synergistic effect exists between sludge and pulverized coal co-combustion. Compared to the weighted calculation results, the content of main elements Si, Ca, Fe and S in PM0.4 decreases, while in PM0.4–10 the content of Si decreases and the content of Ca, Fe, Al, and P increases. At a low sludge addition ratio of 10%, the elemental composition of PM10 with the particle size distribution trend is consistent with that of pulverized coal, and sludge co-firing takes negligible effect on PM10 formation.

Solubility of aerosol minor and trace elements in Xiamen Island, Southeast China: Size distribution, health risk and dry deposition

Aerosol element solubility is essential to evaluate the damage to the environment and human health. In this work, the size distribution of total and soluble elements in eight particle size ranges with diameter <0.25, 0.25–0.44, 0.44–1.0, 1.0–1.4, 1.4–2.5, 2.5–10, 10–16 and >16 μm was investigated in Xiamen Island, southeast China from March 2018 to June 2020. The results showed that both total and soluble elements exhibited significant size dependence without obvious seasonal variations, and their relative contributions to PM1 mass were much lower than in particles larger than 1 μm. The correlations between some elements in soluble fraction were quite different from those in total fraction and the correlations also varied with particle size due to their different solubility. The solubility of Al, Fe, Ag and Cr was relatively low compared with other elements. Moreover, the solubility of Na, Mg, Ca, Mn and Ag was less dependent on particle size while Al, Fe and other trace elements exhibited the highest solubility in PM1 and the lowest in PM>10. Overall, the solubility of elements is primarily a function of aerosol origin and size. The carcinogenic risks of metal exposure via inhalation for children (3.31 × 10−6) and adults (4.42 × 10−6) were slightly higher than the guideline of cancer risk with >60 % from V. As for non-carcinogenic risk, the hazard index values for children and adults were 1.59 and 0.53, respectively, with Mn, V and Ni together accounting for >85 % of the risk. >85 % of the size-dependent dry deposition fluxes of the selected soluble elements over the Xiamen Bay were contributed by particles larger than 10 μm due to their high deposition velocities. The atmospheric inputs of bioavailable Fe and Cu to the sea exceeded the required amounts relative to inorganic nitrogen to meet the growth of phytoplankton.

Physics-based sizing functions for ocean-to-estuary shallow-water models

Modeling ocean processes requires a discrete representation of the system geometry, which itself contains multiple degrees of freedom, especially for systems of large geographical scale. This paper assesses the unstructured meshing requirements for a large-scale, astronomic-tide model domain of the western North Atlantic Ocean, Gulf of Mexico and Caribbean Sea with telescopic focus of the South Atlantic Bight (United States southeastern seaboard) and its estuaries. The methodologies of localized truncation error analysis (LTEA), which account only for the model interior and LTEA plus complex derivatives (+CD), which account for the model interior and boundary, are exploited due to their foundations stemming directly from tidal physics. LTEA and LTEA+CD are applied for the M2 tidal harmonics resulting from linear and nonlinear solutions of the ADCIRC (advanced circulation) model based on a highly resolved uniform mesh. The resultant target element size distributions are interrogated distinctively for the inshore (estuarine) region of the South Atlantic Bight, the inlet-punctuated coastline, the shelf-slope-rise triad and deep ocean, and the open-ocean boundary. The relatively large size of the LTEA computational molecule makes it the suitable choice for the deep ocean, offshore and shelf regions where the tidal dynamics are predominantly linear and smoothly changing in space. LTEA+CD is the logical choice for the shallows and estuaries because of the spatial coverage afforded by the combined utility of interior and boundary estimators (computational molecules), as well as its accounting for the nonlinearities in the evaluation of local truncation error. The combination of the two methods enables an almost complete coverage of the domain for generating spacing requirements, with LTEA+CD extending beyond the interior-only definition of LTEA to capture the inshore regions and model boundaries. Implementing the approach with LTEA and LTEA+CD to target finer resolution in areas with sharper gradients in the hydrodynamics, while relaxing resolution in areas with smoother hydrodynamics, resulted in a mesh with a far-reduced number of elements (∼1.3M) relative to an overly resolved uniform mesh (>10M elements) that is comparable in accuracy with ±5% tidal amplitude error for 99% of the domain.

Terahertz waves dynamic diffusion in 3D printed structures

Applications of metamaterials in the realization of efficient devices in the terahertz band have recently been considered to achieve wave deflection, focusing, amplitude manipulation and dynamical modulation. Terahertz metamaterials offer practical advantages since their structures have typical sizes of hundreds microns and are within the reach of current three-dimensional (3D) printing technologies. Here, we propose terahertz photonic structures composed of dielectric rods layers made of acrylonitrile styrene acrylate realized by low-cost, rapid, and versatile fused deposition modeling 3D-printing. Terahertz time-domain spectroscopy is employed for the experimental study of their spectral and dynamic response. Measured spectra are interpreted by using simulations performed by an analytical exact solution of the Maxwell equations for a general incidence geometry, by a field expansion as a sum over reciprocal lattice vectors. Results show that the structures possess specific spectral forbidden bands of the incident THz radiation depending on their optical and geometrical parameters. We also find evidence of disorder in the 3D printed structure resulting in the closure of the forbidden bands at frequencies above 0.3 THz. The size disorder of the structures is quantified by studying the dynamics diffusion of THz pulses as a function of the numbers of layers of dielectric rods. Comparison with simulations of light diffusion in photonic crystals with increasing disorder allows estimating the size distributions of elements. By using a Mean Squared Displacement model, from the broadening of the pulses’ widths it is also possible to estimate the diffusion coefficient of the terahertz radiation in the photonic structures.