Search

Thermal spray coating is an industrial process in which molten metal is sprayed at high velocity onto a surface as a protective coating. An automated electric arc wire thermal spray coating aerosol generator and inhalation exposure system was developed to simulate an occupational exposure and, using this system, male Sprague–Dawley rats were exposed to stainless steel PMET720 aerosols at 25 mg/m3 × 4 h/day × 9 day. Lung injury, inflammation, and cytokine alteration were determined. Resolution was assessed by evaluating these parameters at 1, 7, 14 and 28 d after exposure. The aerosols generated were also collected and characterized. Macrophages were exposed in vitro over a wide dose range (0–200 µg/ml) to determine cytotoxicity and to screen for known mechanisms of toxicity. Welding fumes were used as comparative particulate controls. In vivo lung damage, inflammation and alteration in cytokines were observed 1 day post exposure and this response resolved by day 7. Alveolar macrophages retained the particulates even after 28 day post-exposure. In line with the pulmonary toxicity findings, in vitro cytotoxicity and membrane damage in macrophages were observed only at the higher doses. Electron paramagnetic resonance showed in an acellular environment the particulate generated free radicals and a dose-dependent increase in intracellular oxidative stress and NF-kB/AP-1 activity was observed. PMET720 particles were internalized via clathrin and caveolar mediated endocytosis as well as actin-dependent pinocytosis/phagocytosis. The results suggest that compared to stainless steel welding fumes, the PMET 720 aerosols were not as overtly toxic, and the animals recovered from the acute pulmonary injury by 7 days. [ABSTRACT FROM AUTHOR]

The current pandemic highlights the significance and impact of air pollution on individuals. When it comes to climate sustainability, air pollution is a major challenge. Because of the distinctive nature, unpredictability, and great changeability in the reality of toxins and particulates, detecting air quality is a puzzling task. Simultaneously, the ability to predict or classify and monitor air quality is becoming increasingly important, particularly in urban areas, due to the well documented negative impact of air pollution on resident's health and the environment. To better comprehend the current condition of air quality, this research proposes predicting air pollution levels from real-time data. This study proposes the use of deep learning techniques to forecast air pollution levels. Layers, activation functions, and a number of epochs were used to create the suggested Long Short-Term Memory (LSTM) network based neural layer design. The use of proposed Deep Learning as a structure for high-accuracy air quality prediction is investigated in this research and obtained better accuracy of nearly 82% compared to earlier records. Determining the Air Quality Index (AQI) and danger levels would assist the government in finding appropriate ways to authorize approaches to reduce pollutants and keep inhabitants informed about the findings. [ABSTRACT FROM AUTHOR]

The quantification and prediction of particulate matter (PM) concentrations in the air are essential due to their negative impacts on human health and the environment. This study quantified PM concentrations and associated health effects at four natural gas-based power plants in Bangladesh. The measurement of PM 2.5 and PM 10 using the respirable dust samplers APS-113NL and APS-113BL, respectively from the year of 2015 to 2021 revealed that the concentration of both types of particles fluctuated over the years. The highest recorded levels of particles were in 2019, with PM 2.5 at 126 µg/m3 and PM 10 at 283 µg/m3 and the lowest recorded levels of particles were in 2017, with PM 2.5 at 76.3 µg/m3 and PM 10 at 203.3 µg/m3. In 2021, PM 2.5 and PM 10 concentrations were 88.5 and 225 µg/m3, respectively, lower than in the past two years. Statistical modeling assessed atmospheric contaminants analyzed time series data, and projected air quality. ARIMA, ETS, and ANN modeling methods have been used to predict the monthly average of PM 2.5 and PM 10 concentrations. RMSE, MAPE, MASE, and MAE have been utilized for model orders, time series analysis, and forecasting validation. There is a significant variation between the forecasting models and forecasts for average PM 2.5 and PM 10 concentrations in natural gas-fired power plants from 2022 to 2024. This study also conducted a face-to-face interview with over 100 employees using a structured questionnaire to assess the health effects they are facing due to poor air quality in the power generation complex and found that 2 and 13 % of employees had respiratory and skin issues, respectively. Nonetheless, regular health checks, air filtration, and renewable energy consumption may benefit residents and the environment. [ABSTRACT FROM AUTHOR]

It is of great significance to understand the particle distribution characteristics at different heights to effectively control particle pollution. Based on fractal theory, the fractal dimension of outdoor particles in a high-rise building in Xi’an and its relationship with the concentration of particles with different particle sizes are discussed and analyzed in this paper. The results indicate that the atmosphere in Xi’an is mainly composed of fine particles and that the average proportion of particles ranging from 0 to 1.0 µm is approximately 99.885% of the total particulates. The fractal dimension of particles in the atmosphere at different heights ranges from 5.014 to 5.764, with an average fractal dimension of 5.456. In summer, the fractal dimension of the outdoor particles on the 17th floor was the largest, at 5.764. The fractal dimension in summer is relatively high, being 0.158 higher than that in winter on average. The larger the fractal dimension, the higher the proportion of fine particles. In addition, the fractal dimension can characterize the adsorption of toxic and harmful gases by particles well. It provides parameter support for understanding particle distribution and the effective control of atmospheric particles at different heights and application values.

Thermal spray coating involves spraying a product (oftentimes metal) that is melted by extremely high temperatures and then applied under pressure onto a surface. Large amounts of a complex metal aerosol (e.g., Fe, Cr, Ni, Zn) are formed during the process, presenting a potentially serious risk to the operator. Information about the health effects associated with exposure to these aerosols is lacking. Even less is known about the chemical and physical properties of these aerosols. The goal was to develop and test an automated thermal spray coating aerosol generator and inhalation exposure system that would simulate workplace exposures. An electric arc wire-thermal spray coating aerosol generator and exposure system was designed and separated into two areas: (1) an enclosed room where the spray coating occurs; (2) an exposure chamber with different measurement devices and controllers. The physicochemical properties of aerosols generated during electric arc wire-thermal spray coating using five different consumable wires were examined. The metal composition of each was determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), including two stainless-steel wires [PMET720 (82 % Fe, 13 % Cr); PMET731(66 % Fe, 26 % Cr)], two Ni-based wires [PMET876 (55 % Ni, 17 % Cr); PMET885 (97 % Ni)], and one Zn-based wire [PMET540 (99 % Zn)]. The particles generated regardless of composition were poorly soluble, complex metal oxides and mostly arranged as chain-like agglomerates and similar in size distribution as determined by micro-orifice uniform deposit impactor (MOUDI) and electrical low-pressure impactor (ELPI). To allow for continuous, sequential spray coating during a 4-hr exposure period, a motor rotated the metal pipe to be coated in a circular and up-and-down direction. In a pilot animal study, male Sprague-Dawley rats were exposed to aerosols (25 mg/m3 × 4 h/d × 9 d) generated from electric arc wire- thermal spray coating using the stainless-steel PMET720 consumable wire. The targeted exposure chamber concentration was achieved and maintained during a 4-hr period. At 1 d after exposure, lung injury and inflammation were significantly elevated in the group exposed to the thermal spray coating aerosol compared to the air control group. The system was designed and constructed for future animal exposure studies to generate continuous metal spray coating aerosols at a targeted concentration for extended periods of time without interruption.

Particulate matter (PM) and ozone (O3) are dominant air pollutants that contribute to development and exacerbation of multiple cardiopulmonary diseases. Mature adults with cardiovascular disease (CVD) are particularly susceptible to air pollution-related cardiopulmonary morbidities and mortalities. The aim was to investigate the biologic potency of ultrafine particulate matter (UFPM) combined with O3 in the lungs of mature adult normotensive and spontaneously hypertensive (SH) Wistar-Kyoto rats. Conscious, mature adult male normal Wistar-Kyoto (NW) and SH rats were exposed to one of the following atmospheres: filtered air (FA); UFPM (∼ 250 μg/m3); O3 (1.0 ppm); or UFPM + O3 (∼ 250 μg/m3 + 1.0 ppm) combined for 6 h, followed by an 8 h FA recovery period. Lung sections were evaluated for lesions in the large airways, terminal bronchiolar/alveolar duct regions, alveolar parenchyma, and vasculature. NW and SH rats were similarly affected by the combined-pollutant exposure, displaying severe injury in both large and small airways. SH rats were particularly susceptible to O3 exposure, exhibiting increased injury scores in terminal bronchioles and epithelial degeneration in large airways. UFPM-exposure groups had minimal histologic changes. The chemical composition of UFPM was altered by the addition of O3, indicating that ozonolysis promoted compound degradation. O3 increased the biologic potency of UFPM, resulting in greater lung injury following exposure. Pathologic manifestations of CVD may confer susceptibility to air pollution by impairing normal lung defenses and responses to exposure.

Exposure to particulate matter (PM) and pollutant gas (NOx) is associated with increased cardiopulmonary morbidity and mortality. Mobile source emissions contribute to PM and NOx emissions significantly in urban areas. Hybrid Electric Vehicles (HEVs) plays an important role to reduce emissions. While sales of electric vehicles has been increasing, electric vehicles have to overcome issues with charging time, driving range, and production/sales cost for more widespread market penetration. Hybrid electric vehicles have a potential to serve as a bridge technology between current internal combustion engine powered vehicles and zero emissions vehicles such as electric vehicles and fuel cell vehicles. Current regulations require emissions to be tested on a chassis dynamometer. However, it is known that on-road emissions can be quite different from that those measured on regulatory driving cycles in the lab. In this study, emissions from two HEVs with different combustion technologies (gasoline direction injection vs port fuel injection) were compared using PEMS (portable emissions measurement system) and tailpipe sensors under cold weather conditions. The study has found the frequency and duration of re-ignition events vary depending on the type of HEV. Prius (PFI HEV) showed more frequent re-ignition events compared to Sonata (GDI HEV) for both city and highway driving conditions. Prius re-ignited almost every one minute while Sonata re-ignited every two minutes on average during the city driving condition. Reignition events affected emissions profile significantly during the city driving condition. As a result, Prius showed higher NOx emissions during the city driving condition while Sonata showed higher NOx emissions during the cold-cold start and highway driving condition. For PM emissions, PFI technology is known to make minimal amount of soot which is shown in the cold-cold start result while GDI technology is more prone to generating soot. This gap is reduced in city and highway driving condition due to more frequent re-ignition events of the PFI HEV (referring to Prius). Future studies should include more vehicles to understand whether the re-ignition events are vehicle specific or technology specific.View the NCST Project Webpage

Metal-organic frameworks (MOF) are emerging materials with fantastic properties and wide applications. The release of metal ions from MOF materials is usually regarded as the origin of soluble MOF toxicity. However, whether the stable MOF particulates would induce environmental hazards is not clear. Herein, we aimed to reveal the particulate toxicity of MOF materials using the insoluble UiO-66 as the representative MOF and Phanerochaete chrysosporium as the model microorganism. UiO-66 nanoparticles (NPs) were synthesized by solvothermal method and their diameter was 68.4 ± 8.5 nm. UiO-66 NPs were stable in the culture system and the dissolution rate of 500 mg/L group was 0.26% after 14 d incubation. UiO-66 NPs did not affect the fungus growth according to the fresh weight increases and unchanged dry weights. Fungus mycelia kept even at concentrations up to 500 mg/L. Ultrastructural observation showed that UiO-66 NPs did not enter the fungal cells, but slightly destroyed the cell wall. UiO-66 NPs inhibited the laccase activity and promoted the activity of manganese peroxidase. The overall impact on the decomposition activity of P. chrysosporium was low in dye coloration test and sawdust degradation assay. Meaningful oxidative stress was aroused by UiO-66 NPs, as indicated by the decreases of catalase, glutathione, and total superoxide dismutase, and the increases of H2O2. Our results collectively suggested that the MOF particulates could induce mild mechanical damage to fungi and the toxicity was low comparing to other instable MOF materials.

The objective of this study was to determine the extent that nebulized glycosylated caffeic acid phenylether ester-4-O-alpha-D-glucopyranoside (G-CAPE) attenuates particulate-induced airway inflammation in healthy horses. Our hypothesis was that nebulization with G-CAPE would result in improved respiratory scores, higher arterial oxygen partial pressure, and less inflammatory airway infiltrates in horses with induced airway inflammation, compared with untreated controls. Five healthy adult horses were housed inside a climate controlled, closed barn on straw bedding and fed ad lib moldy grass hay for 16 days to induce airway inflammation. An experimental crossover study was performed in which animals were treated with 200 mg G-CAPE dissolved in 45 mL of 10% triethanolamine (G-CAPE group) or 45 mL of 10% triethanolamine (CONTROL group), and clinical respiratory scoring, arterial blood gases, and bronchoalveolar lavages (BALs) were collected at predetermined time points up to 24 h post nebulization. While the mean neutrophil percentage decreased in treated horses compared to controls (9.3 ± 2.0 and 16.9 ± 2.4, respectively) at 6 hours post treatment (t = 6 h), the difference did not achieve statistical significance (p = 0.1154). Blood gas analysis did not differ significantly between groups. There was a significant difference in the mean respiratory scores of G-CAPE-treated horses between baseline and at 1-h post treatment (from 3.2 ± 0.7 to 1.6 ± 0.7, p = 0.0013). This study demonstrates that a single nebulized dose of G-CAPE decreased clinical respiratory scores 1 h post administration and decreased BAL percentage of neutrophils 6 h post administration in horses with particulate induced airway inflammation. This compound shows promise as an anti-inflammatory and warrants further investigation.

In this study, the authors evaluate the hygroscopicity and droplet kinetics of fresh and aged emissions from new generation gasoline direct injector engines retrofitted with a gasoline particulate filter (GPF). Furthermore, ageing and subsequent secondary aerosol formation is explored in (NH4)2SO4-seeded and non-seeded experiments. The authors explore the impacts on measured and predicted hygroscopicity, CCN-activity, and droplet kinetics of secondary aerosol mixed with initially insoluble carbonaceous materials versus very soluble (NH4)2SO4 seed. The chemical composition and density of the secondary aerosol (SA) formed from aging is measured with an HR-TOF-AMS and a custom-built APM-SMPS system. The supersaturated and subsaturated hygroscopicity of the fresh and aged emission is measured with a DMT Streamwise Thermal Gradient CCN counter and a hygroscopicity tandem differential mobility analyzer (HTDMA), respectively. The measurements show that the fresh gasoline emissions are only slightly hygroscopic in both supersaturated and subsaturated environments. Photochemical aging and subsequent condensation of the secondary aerosol formed from the co-emitted gas phase precursors increases the hygroscopicity of gasoline emissions. Without the GPF, both subsaturated and supersaturated hygroscopicity. When the engine was retrofitted with the GPF, the secondary aerosol (SA) experiments were seeded with (NH4)2SO4. In these experiments the presence of the condensing SA depresses the hygroscopicity of the salt-secondary aerosol mixture. The hygroscopicity was also depressed in the subsaturated regime with time. These changes in the hygroscopicity with aging were additionally sensitive to aerosol dry size distribution. The authors also used threshold droplet growth analysis (TDGA) to evaluate the effects of the condensing SA on droplet kinetics. These results have important implications for the assessment of cloud-aerosol indirect effects of salt-seeded and black carbonaceous aerosol cores. The authors concluded that in the new generation GDI vehicles the point of aerosol emissions will have significant influence on the impacts of the secondary and primary aerosols on climate.View the NCST Project Webpage

[Display omitted] Insulin is a biotherapeutic protein, which, depending on environmental conditions such as pH, has been shown to form a large variety of aggregates with different structures and morphologies. This work focuses on the formation and characteristics of insulin particulates, dense spherical aggregates having diameters spanning from nanometre to low-micron size. An in-depth investigation of the system is obtained by applying a broad range of techniques for particle sizing and characterisation. An interesting observation was achieved regarding the formation kinetics and aggregate characteristics of the particulates; a subtle change in the pH from pH 4.1 to pH 4.3 markedly affected the kinetics of the particulate formation and led to different particulate sizes, either nanosized or micronsized particles. Also, a clear difference between the secondary structure of the protein particulates formed at the two pH values was observed, where the nanosized particulates had an increased content of aggregated β-structure compared to the micronsized particles. The remaining characteristics of the particles were identical for the two particulate populations. These observations highlight the importance of carefully studying the formulation design space and of knowing the impact of parameters such as pH on the aggregation to secure a drug product in control. Furthermore, the identification of particles only varying in few parameters, such as size, are considered highly valuable for studying the effect of particle features on the immunogenicity potential. [ABSTRACT FROM AUTHOR]

The presence of metalloids and heavy metals in the environment is of critical concern due to their toxicological impacts. However, not all metallic species have the same risk level. Specifically, the physical, chemical, and isotopic speciation of the metal(loids) dictate their metabolism, toxicity, and environmental fate. As such, speciation analysis is critical for environmental monitoring and risk assessment. In the past two decades, surface-enhanced Raman spectroscopy (SERS) has seen significant developments regarding trace metal(loid) sensing due to its ultrahigh sensitivity, readiness for in situ real-time applications, and cost-effectiveness. However, the speciation of metal(loid)s has not been accounted for in the design and application of SERS sensors. In this Perspective, we examine the potential of SERS for metal(loid) speciation analysis and highlight the advantages, progress, opportunities, and challenges of this application.

Trends and sources of air pollution at twenty-five traffic Intersections (TIs) before and during covid-19 lockdown were investigated in Ibadan, Nigeria. The relationships among climatic parameters, vehicular counts and ten air pollutants which includes particulate matter (PM1, PM2.5, PM10 & Total Suspended Particles-TSP) and gaseous pollutants (CO, NO2, SO2, NH3, total volatile organic compounds-TVOCs, and ground level O3) measured simultaneously at TIs were analysed. Results indicated significant decrease in mean concentrations of all pollutants studied except NO2 with 212% increase during the study period. Concentrations of gaseous pollutants CO, SO2, NH3, TVOCs and ground level O3 reduced by 7.92%, 24.80%, 1.58%, 44.08% and 4.28%, respectively while particulates concentrations of PM1, PM2.5, PM10 and TSP concentrations decreased by 49.64%, 60.79%, 81.21% and 84.17%, respectively during lockdown. An integrated source apportionment approach using Pearson’s correlation, Airflow backward trajectories arriving in the study area and Principal component analysis (PCA) identified vehicular emission as the primary source of studied air pollutants at TIs before and during lockdown in Ibadan. Emission from residences, roadside fuel combustion and local air transport of pollutants from nearby upwind areas with industries and farming activities were identified as secondary sources of air pollution affecting the study area.

Background: Some evidences have shown the association between air pollution exposure and the development of interstitial lung diseases. However, the effect of air pollution on the progression of restrictive ventilatory impairment and diffusion capacity reduction is unknown. This study aimed to evaluate the effects of long-term exposure to ambient air pollution on the change rates of total lung capacity, residual volume, and diffusion capacity among the elderly.Methods: From 2016 to 2018, single-breath helium dilution with the diffusion capacity of carbon monoxide was performed once per year on 543 elderly individuals. Monthly concentrations of ambient fine particulate matters (PM2.5) and nitric dioxide (NO2) at the individual residential address were estimated using a hybrid Kriging/Land-use regression model. Linear mixed models were used to evaluate the association between long-term (12 months) exposure to air pollution and lung function with adjustment for potential covariates, including basic characteristics, indoor air pollution (second-hand smoke, cooking fume, and incense burning), physician diagnosed diseases (asthma and chronic airway diseases), dusty job history, and short-term (lag one month) air pollution exposure.Results: An interquartile range (5.37 ppb) increase in long-term exposure to NO2 was associated with an additional rate of decline in total lung volume (- 1.8% per year, 95% CI: - 2.8 to - 0.9%), residual volume (- 3.3% per year, 95% CI: - 5.0 to - 1.6%), ratio of residual volume to total lung volume (- 1.6% per year, 95% CI: - 2.6 to - 0.5%), and diffusion capacity (- 1.1% per year, 95% CI: - 2.0 to - 0.2%). There is no effect on the transfer factor (ratio of diffusion capacity to alveolar volume). The effect of NO2 remained robust after adjustment for PM2.5 exposure.Conclusions: Long-term exposure to ambient NO2 is associated with an accelerated decline in static lung volume and diffusion capacity in the elderly. NO2 related air pollution may be a risk factor for restrictive lung disorders. [ABSTRACT FROM AUTHOR]

The research investigates the morphology and wear behaviours of Al–Mg-Si alloy reinforced with palm kernel shell powder (PKSP) for developing composites. PKSP with particle size of 100 μm was prepared for the studies at different weight percentages of 3, 6, 9, 12, and 15 PKSP to developed composites for the investigations. The PKSP was characterized by X-ray fluorescence (XRF). The morphology of the alloy and composites was characterized by scanning electron microscopy (SEM) attached with energy-dispersive spectroscopy (EDS). The XRF revealed elements such as carbon (C) and oxygen (O2) with other elements as traces. The PKSP as a reinforcer had improved the morphology and wear rate behaviours positively. Morphologies revealed that the composites produced showed no voids and discontinuities of PKSP particulates in the composites. The wear resistance of the matrix and composites increases with increase in load and decreases with increase in the weight percentage of PKSP. The minimum wear rate was obtained at the load of 10 N while highest at an applied load of 30 N. The wear rate of the alloy lost under load of 10 N was 1.31 times greater than that of alloy reinforced with 15 wt.% PKSP with minimum wear rate. The composites could be used as brake rotors, pistons, and connecting rods in the automobile industries. [ABSTRACT FROM AUTHOR]

Rainwater can be harvested from different roofs of rural buildings, which can be stored for multipurpose depending on its quality. This technical note describes rainwater quality collected directly from the atmosphere and after passing through four types of roofs that are: French ceramic (roof1/Agronomy school building), fiber cement (roof2/farm machinery shed), or French ceramic (roof3/sheep housing), and French ceramic (roof4-swine housing) located inside Agroveterinary School Campus (CAV/UDESC) in Lages, Santa Catarina state, Brazil. The parameters analyzed were pH, color, turbidity, dissolved oxygen, total coliforms, and thermotolerant coliforms. Results showed that pH "in natura" rainwater was variable and below 7.0 with an average of 6.02. However, after passing through the roof, there was an increase in the pH (average) to 6.34 (roof1), 6.90 (roof2), 7.14 (roof3) and 6.50 (roof4). The rainwater also presented variations in the parameters of turbidity, dissolved oxygen, and coliforms after passing through roofs. Thus, the rainwater can potentially be used for non-potable purposes, being then advised of their use without treatment for cleaning of nearby environments of these rural buildings, as well as the irrigation of trees and ornamental plants, among others. [ABSTRACT FROM AUTHOR]

Lubricant foaming and its mitigation is an active area of research driven by demands from modern machinery that require foam-free lubricant operation over extended periods and under adverse conditions. Tackling lubricant foaming has proven to be challenging due to interdependent foam stabilization mechanisms and a multitude of antifoam inactivation routes. This perspective briefly outlines the key challenges faced by researchers in this field. Overcoming these challenges to create lubricants with superior foaming characteristics requires the development of new lubricant and antifoam chemistry as well as a shift from the existing trial-and-error methods to mechanistic-insight-driven lubricant formulation and antifoam design. [ABSTRACT FROM AUTHOR]

Some of the most important questions in the development of sustainable transportation are identify fuels that will reduce emissions, provide diversification from fossil fuels, reduce greenhouse gas emissions, be produced from renewable sources, and that can be produced in a sustainable manner. An alternative diesel fuel that could be used for particulate matter (PM) reductions and be produced from renewable sources could represent a key advance for the transportation sector in terms of sustainability, diversification for the marketplace for the alternative fuels, emissions reductions, and reductions in greenhouse gases. Dimethyl carbonate (DMC) is a potentially new fuel that could represent an important advance in the diesel fuel area. DMC can be produced from renewable sources such as grass, manure, or trees. Preliminary tests at the University of California at Riverside have also indicated PM reductions of about 76% at only a 20% blend with diesel fuel, which is about double or triple the reductions typically found for biodiesel at a comparable blend level, and comparable to the reductions found for diesel particulate filters (DPFs). Although these preliminary results indicate the promise of DMC as a PM mass reduction strategy, it is important to more completely characterize the emissions and viability of DMC before it can be more widely used in the fuel market or for in-field demonstrations. The objective of this study was to conduct a preliminary evaluation of the viability of DMC as a transportation fuel for fleet and wider applications. This included a literature review to address questions related to air emissions, impact on vehicle system durability and parts, and any potential storage issues. This study also included some additional emissions testing to evaluate any emissions of toxic species, and to look at some optimization of blend level in terms of a full range of emissions components.View the NCST Project Webpage

Utilizing solid particles as a heat-transfer medium in concentrated solar power applications has gained growing attention lately. Unlike molten salts, solid particles offer many benefits, which include: high operating temperatures (greater than 1000 °C), a lack of freezing issues and corrosivity, abundant availability, high thermal energy storage capacity, a low cost, and applicability in direct irradiation. Comprehensive knowledge of thermophysical and optical properties of solid particles is essential to ensure an effective harnessing of solar energy. The most important considerations when selecting solid particles include: thermophysical and optical properties, thermal resistance, crack resistance, satisfactory health and safety risks, availability, and low cost. It is also imperative to consider optical and thermophysical characteristics that might change from what they were "as received" after cyclic heating for a long period. Therefore, the knowledge of thermal performance of particulate materials becomes significant before using them as a heat-transfer medium. In this study, some particulate materials were chosen to study their feasibilities as heat-transfer and storage media for a particle-based central receiver tower system. These particulate materials included white sand, red sand, ilmenite, and Carbobead CP. The candidate particulate materials were heated at high temperatures for 6 h and then cooled to room temperature. After that, cyclic heating was performed on the particulate materials for 500 h at 1200 °C. The optical properties were represented by weighted solar absorptance, and the thermophysical properties of the particulates were measured "as received" and after cyclic heating (aging). EDX and XRD were conducted to quantify the chemical composition and interpret the changes in appearance associated with the particulate materials after cyclic heating. The results showed a considerable agglomeration in all particulates except for white sand in the 6 h heating test, and high agglomeration in the ilmenite. A slight decrease in the optical properties in the white sand and Carbobead CP was found after the aging test. The specific heat was decreased for red and white sand. The EDX and XRD results for white sand and Carbobead CP showed chemical stability, indicating high durability and reliability. [ABSTRACT FROM AUTHOR]

Dust generation and dispersion continue to be a major concern for many in the industries that rely on bulk materials handling, and the ability to predict dust generation and dispersion remains challenging. This study looks at the use of computational fluid dynamics (CFD) and discrete element method (DEM) as a means of predicting dust generation and dispersion. The paper outlines work completed on predicting dust dispersion during the loading process of a bulk carrier using the Rotabox™ system for a stevedoring company at a port in Australia. CFD simulations are conducted to analyze the induced air flow generated inside the cargo hold of a bulk carrier including typical cross-wind conditions. Coupled CFD-DEM simulations are conducted to analysis the air flow inside the cargo hold driven by the unloading of the bulk material. Dust particle free-settling time is used to assess the dust cloud formation and dispersion based on the flow conditions predicted by CFD-DEM simulations. The study finds that the unloading process is likely to disperse dust into the cargo hold at a level that without dust suppression would result in dust being dispersed into the broader environment by the typical cross-wind conditions at the port. [ABSTRACT FROM AUTHOR]

This study assesses whether the use of Tessaria absinthioides (TA) pellets as a bioenergy resource is feasible or not. Its fuel properties were characterized and its combustion behavior assessed via a traditional log wood stove with a basket of wood pellets. Combustion of pinewood (Pinus radiata) commercial pellets (CP) was used as a reference in order to analyze experimental results. TA has a high ash content of 8.1% and an HHV of 17.47 MJ kg−1. Alkaline index on the TA pellets was of 1.46 kg alkali GJ−1, a relatively high value, which resulted from high sodium content in ash. Oven and exhaust temperatures during the combustion of TA and CP present similar behavior. The combustion chamber's highest temperature for CP was 841.15 °C, while for TA, the highest temperature was 685.65 °C. Furthermore, CO and PM emission was superior for TA pellets, averaging about 4943.6 ± 235.2 mg Nm−3 and 32.45 ± 6.49 mg MJ−1, respectively at 13% O2. Results obtained have shown that there were no apparent hindrances for an extensive use of TA as a bioenergy resource and use of pellet baskets to combust pellets in traditional wood log stoves. [ABSTRACT FROM AUTHOR]

The mechanism of separation methods, for example, liquid chromatography, is realized through rapid multiple adsorption‐desorption steps leading to the dynamic equilibrium state in a mixture of molecules with different partition coefficients. Sorting of colloidal particles, including protein complexes, cells, and viruses, is limited due to a high energy barrier, up to millions kT, required to detach particles from the interface, which is in dramatic contrast to a few kT for small molecules. Such a strong interaction renders particle adsorption quasi‐irreversible. The dynamic adsorption‐desorption equilibrium is approached very slowly, if ever attainable. This limitation is alleviated with a local oscillating repulsive mechanical force generated at the microstructured stimuli‐responsive polymer interface to switch between adsorption and mechanical‐force‐facilitated desorption of the particles. Such a dynamic regime enables the separation of colloidal mixtures based on the particle‐polymer interface affinity, and it could find use in research, diagnostics, and industrial‐scale label‐free sorting of highly asymmetric mixtures of colloids and cells. [ABSTRACT FROM AUTHOR]

Anti-inflammatory and proinflammatory responses in macrophages are influenced by cellular metabolism. Macrophages are the primary phagocyte in mucosal environments (i.e., intestinal tract and lungs) acting as first-line defense against microorganisms and environmental pollutants. Given the extensive contamination of our food and water sources with microplastics, we aimed to examine the metabolic response in macrophages to microplastic particles (MPs). Utilizing murine macrophages, we assessed the metabolic response of macrophages after polystyrene MP phagocytosis. The phagocytosis of MP by macrophages induced a metabolic shift toward glycolysis and a reduction in mitochondrial respiration that was associated with an increase of cell surface markers CD80 and CD86 and cytokine gene expression associated with glycolysis. The gastrointestinal consequences of this metabolic switch in the context of an immune response remain uncertain, but the global rise of plastic pollution and MP ingestion potentially poses an unappreciated health risk. Macrophage phagocytosis of microplastics alters cellular metabolism. - Macrophages cannot degrade PS MP. - MP phagocytosis increases glycolysis in murine macrophages. - MP phagocytosis reduces mitochondrial respiration in murine macrophages. [ABSTRACT FROM AUTHOR]

The biodegradable and naturally available waste Syzygium cumini particulates filled E‐glass fiber laminate‐reinforced composites were fabricated with different weight percentages. The present work is to develop a new composite from huge waste of S. cumini seeds. The two different combinations of composites with different concentration (10, 20, 30, 40, and 50 wt%) of reinforcement were fabricated through open layup molding techniques. Functional groups, X‐ray diffraction, surface morphology, carbon, hydrogen, nitrogen and sulphur (CHNS) elemental analysis, and mechanical characteristics (tensile, flexural strength, and hardness) of fabricated composites were evaluated. The maximum tensile strength, flexural strength, and maximum Shore D hardness of the composite were found to be 14.04 ± 0.5 MPa, 1603 ± 0.5 MPa, and 92 ± 0.5 SHN, respectively. By incorporating E‐glass fiber laminate on both sides of the S. cumini particulates filled epoxy composite enhanced mechanical properties compared with S. cumini particulates filled epoxy composites. The results showed that these composites can be utilized as panels for low strength applications. [ABSTRACT FROM AUTHOR]

The present study assessed the impacts of seasonal variation on the atmospheric abundance of gaseous air pollutants (SO2, NO2, O3, CO) and particulates (PM2.5 and PM10) at Gazipur city. The air pollution data was collected from the study area using a Continuous Air Monitoring Station (CAMS) (CAMS-4, Gazipur) of DoE from October 2017 to September 2018. The highest concentrations of air pollutants were found in the winter (PM2.5=208 μg/m3, PM10=300 μg/m3, NO2=45.1 ppb, CO=3.91 ppm, O3=4.17 ppb) as opposed to those of the post-monsoon (PM2.5=133μg/m3, PM10=169 μg/m3, NO2=23.52 ppb, CO=2.25 ppm, O3=7.71 ppb), pre-monsoon (PM2.5=115 μg/m3, PM10=216 μg/m3, NO2=33.5 ppb, CO=1.75 ppm, O3=4.23 ppb), and monsoon (PM2.5=37.5 μg/m3, PM10=85.6 μg/m3, NO2=13.9 ppb, CO=0.84 ppm, O3=4.23 ppb). The highest concentration of five air pollutants (PM10, PM2.5, NO2, CO, O3)indicated that the higher pollutant load in the winter was associated with large-scale polluted air transported from the brick kiln at a distance of 5-7 km at the sampling site. The wind-rose data analysis indicated that most of the air during the winter season came to the sampling site from the northern part of the Gazipur district, from the brickfield zones. In contrast, a reverse relationship between the rainfall and atmospheric pollution, temperature, and atmospheric pollution load was observed during the pre-monsoon, monsoon, post-monsoon, and winter. This finding revealed that the lowest concentration of air pollutants during monsoon was associated with the washout effect of precipitation on atmospheric pollutants. A moderate correlation (R2=0.58) between CO and O3 pollutants during the study indicated their atmospheric origin by photochemical reactions was associated with volatile organic compounds (VOCs). PM2.5 showed a positive correlation with PM10 (R2=0.84), indicating that both PM2.5 and PM10 were produced from similar pathways of fossil fuel combustion by automobiles and industrial activities. Further, the air quality index (AQI) analysis showed unhealthy atmospheric conditions throughout the year for city dwellers around the study area.

Coal-based energy production is the most utilized method of electricity production worldwide and releases the highest concentration of gaseous, particulate, and metallic pollutants. Toxicological research has shown that coal combustion by-products are carcinogens, endocrine disruptors, and cardiorespiratory toxins. This article aims to systematically review the epidemiological literature on the impact emissions from coal-based power production has on morbidity and mortality worldwide. Two thousand one hundred and fifty-two articles were retrieved based on search criteria. Word search of abstract and article text filtered the results to 95 articles. Forty articles were included after screening. The literature indicates a significant adverse effect from particulate matter and polyaromatic hydrocarbon emissions on morbidity and mortality. There is a lack of consistency of exposure assessment and inadequate control of significant potential confounders such as social economic status. Future research should focus on improving exposure assessment models, specifically source-apportionment and geographic information system methods to model power plant-specific emissions. [ABSTRACT FROM AUTHOR]