Journal articles on the topic 'Particulates'
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1
Hunter, C. E., H. A. Cikanek, and T. P. Gardner. "Evaluation of Some Factors Controlling DI Diesel Combustion and Exhaust Emissions." Journal of Engineering for Gas Turbines and Power 111, no. 3 (July 1, 1989): 379–86. http://dx.doi.org/10.1115/1.3240265.
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The combined effects of turbocharging, high fuel injection pressure, and reduced oil consumption on diesel exhaust emissions were investigated using a single-cylinder research engine. The influence of these exhaust emission control concepts on particulate composition was determined using a new particulate analysis method. In addition, the dependence of particulate composition on engine load and air utilization was examined using the microfumigation technique. Simultaneous application of these emissions control concepts reduced exhaust particulates by 70 percent. High injection pressure reduced the insoluble component of particulates, while reducing oil consumption and turbocharging the engine lowered both soluble and insoluble particulates. Reductions in oil-derived particulates with increasing engine load were partially attributed to increases in volumetric air utilization. Ninety percent of the lube oil found in exhaust particulates was unburned; however, similar concentrations of unburned and partially oxidized components were observed in fuel-derived particulates.
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Guo, Su Juan, Guo Zheng Kang, and Cheng Dong. "Numerical Simulations for Uniaxial Ratcheting of SiCP/6061Al Composites Concerning Particulate Arrangement." Advanced Materials Research 26-28 (October 2007): 317–20. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.317.
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Based on three dimensional cubic unit cell models containing several particulates with certain particulate arrangements, the monotonic tensile and uniaxial ratcheting behaviors of particulate reinforced metal matrix composites (i.e., T6-treated SiCP/6061Al composites) were numerically simulated by using elastic-plastic finite element code ABAQUS with help of newly developed user material subroutine (UMAT). In the simulations, the effects of different particulate arrangements inside the unit cell models on the monotonic tensile and ratcheting behaviors of the composites were discussed. It is shown that the effect of particulate arrangement on the ratcheting of the composite depends on the arranged modes and the number of particulates contained in the model, and the interaction between particulates can be represented reasonably by the cubic unit cell model with a suitable distribution of multi-particulates.
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Fang, Guor-Cheng, Yuh-Shen Wu, Wen-Jhy Lee, Te-Yen Chou, and I.-Chen Lin. "Seasonal variation in concentration and metallic constituents of atmospheric particulates near the western coast of central Taiwan." Toxicology and Industrial Health 22, no. 5 (June 2006): 193–201. http://dx.doi.org/10.1191/0748233706th262oa.
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In addition to determining the concentration and metallic constituents of particulate matter at Taichung Harbor in central Taiwan, this study attempts to characterize the mass, metallic elements, composition and concentrations of total suspended particulates (TSP), fine particles and coarse particles. Statistical approaches, such as the Spearman tests, were also adopted to determine the seasonal variations of concentrations of these pollutants. Experimental results indicate that the mean TSP, fine particulate and coarse particulate concentrations in spring and winter are higher than in summer and autumn on the western coast of central Taiwan. Spearman statistical analysis of metallic elements Mn and Pb showed high concentration coefficients for fine and coarse particulates on the western coast of central Taiwan. The order of mean metallic concentrations in TSP, coarse particulates and fine particles was Fe-Zn-Mg-Cu-Cr-Mn-Pb in TSP, Fe-Cu-Zn-Mg-Mn-Pb-Cr in coarse particulates and Fe-Cu-Mg-Pb-Zn-Mn-Cr in fine particulates.
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Kim, Yeon Ju, Yeon-Dong Kim, Hyungtae Kim, Dong Ji Ahn, Ha-Jung Kim, Won Uk Koh, and Young-Jin Ro. "Interaction between Dexamethasone, Ropivacaine, and Contrast Media Used in Interventional Pain Treatment: Considerations in Safety." Medicina 58, no. 12 (December 19, 2022): 1871. http://dx.doi.org/10.3390/medicina58121871.
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Background and Objectives: Although epidural steroid injections are used as an effective treatment, this technique is associated with rare but serious ischemic complications, especially when particulate steroids are used. However, recent studies have reported that even if non-particulate steroids are used, particulates are formed by the interaction with some local anesthetics (LA), causing ischemic complications. This observational study evaluated commonly used combinations of non-particulate steroids and LA with contrast media via microscopic analysis and analyzed the chemical properties of each mixture to identify the correlation of particulate formation. Materials and Methods: Commonly used clinical non-particulate and particulate steroids, contrast media, and LA agent combinations were evaluated macroscopically and microscopically. The pH values were also measured at both room temperature (26 °C) and body temperature (36 °C). Where particulates were observed, the particulate size was measured. Results: Macroscopically, the mixture of non-particulate steroid and ropivacaine had a slightly cloudy appearance at all concentrations, but there was no visible particulate. However, when observed under a microscope, the pH-dependent particulate formation was observed at all concentration combinations tested. (0.1% ropivacaine: from 19 μm to 70 μm, and 0.2% ropivacaine: from 37 μm to 108 μm at room temperature (26 °C)). When contrast media was mixed or the temperature was raised to body temperature (36 °C), the number and size of the particulates decreased or dissolved. Conclusions: The combination of ropivacaine and dexamethasone, a non-particulate steroid, mainly used in epidural injections, forms particulates. However, when mixed with contrast media, particulates are dissolved because of changes in pH and factors affecting particulate formation. In fluoroscopy-guided injections, the use of contrast media could resolve particulate formation.
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Fan, Long, and Shimin Liu. "Respirable nano-particulate generations and their pathogenesis in mining workplaces: a review." International Journal of Coal Science & Technology 8, no. 2 (February 11, 2021): 179–98. http://dx.doi.org/10.1007/s40789-021-00412-w.
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AbstractThere is a growing concern in mining community about the contribution of nano-particulates to miner’s health. Despite the health influence of respirable dusts and associated lung diseases have been recognized for decades in the mining industry, the nano-scale particulates accompanying with complicated physiochemical properties and their enormous contribution in quantity have been drawing attentions only in recent a few years because of the advancement of nano-science discipline. In this review, we examine the current regulations of dusts exposure and the dominant mass-based monitoring methods to point out the ignorance of nano-particulates in mining industry. The recognized mining-related nano-particulates sources are summarized to identify the mechanically generated finer particulates including particles and aerosols. In addition, the mechanism of adverse health impact on miner with exposure to nano-scale particulates is discussed in a detail to emphasize their substantial detriment as a potential respiratory hazard. Characterization of the complex physiochemical properties of nano-particulates are then summarized and discussed because these properties could be different from regular respirable dusts due to their dramatically increased surface area and particulate counts. The intent of this review is to demonstrate the potential of adverse health effect of nano-particulate on the mine personals throughout the mining cycle and to identify the research gaps of the mine nano-particulate characterization and quantification. We suggest that further understanding of the mining induced nano-particulate properties and their pathogenesis are critical for the future engineering control measure to mitigate the potential health threat for future miners.
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Danciulescu, Valeriu, Luoana Florentina Pascu, Mihaela Petrescu, Andreea Cozea, Raluca Diodiu, Gheorghita Tanase, and Maria Pasca. "The influence of emission sources on particulate matter pollution in adjacent areas." SIMI 2019, SIMI 2019 (September 20, 2019): 253–58. http://dx.doi.org/10.21698/simi.2019.fp33.
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Particulates generated by anthropogenic activities are found in the ambient air in varying amounts, in a wide range of sizes and in a wide variety of chemical composition. The concentration of particulates at one site, as well as their composition, are influenced by their origin and dispersion factors. By chemical and dimensional analysis of particulates in an area, we can draw preliminary conclusions about the origin and level of pollution in that area. This paper presents the results obtained by concomitant monitoring of particulates emissions and the concentration of particulate matter in ambient air in the adjacent area of an industrial plant. The result of the measurements obtained and their correlation with the specific conditions during the monitoring period lead us to the conclusion that the concentration of particulate matter at the emission sources directly influences the concentrations of particulate matter in the neighbouring area.
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Darien, B. J., P. Sims, T. Robinson, P. Manley, and R. Albrecht. "Characterization of Titanium Alloy Particulates to Study the in Vitro Release of Inflammatory Mediators by Human Peripheral Blood Monocytes." Microscopy and Microanalysis 4, S2 (July 1998): 940–41. http://dx.doi.org/10.1017/s143192760002482x.
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Particulate wear debris found around joint arthroplasties has been linked to the premature failure of artificial joints. Cytokines and eicosanoids released by macrophages are known mediators of inflammation and osteolysis. Previous in vitro studies of wear debris-mediated inflammation have relied upon poorly characterized particulates and peripheral blood cell fractions of mixed cellular composition. The objective of this study was to utilize titanium particulates that closely match wear debris found around joint arthroplasties and to study their effects on the biosynthesis of inflammatory mediators by isolated monocytes.To mimic wear debris that surrounds artificial joints, titanium alloy particulates (1-3 μm in diameter) were obtained. A submicron fraction of these particulates was isolated by differential sedimentation. The morphology, size and concentration of the resulting population was characterized utilizing scanning electron microscopy. Titanium particulate size was estimated from photomicrographs of calibrated latex microspheres mixed with titanium particles (Figure 1). A known volume of titanium particulates in suspension was applied to a carbon planchette and allowed to dry.
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Yu, Yun Jiang, Qiong Wang, Zhong Ren Nan, Yan Ping Zhang, Hai Peng Lin, and Sheng Li Wang. "Distribution Characteristics and Health Risk Assessment of Heavy Metal Pollutants on Air Particulate Matters in Lanzhou City." Advanced Materials Research 518-523 (May 2012): 961–69. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.961.
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In order to learn the present situation of heavy metals on particulate matters and evaluate their health risk, this paper cites the examples of District Xigu which is severely polluted and Town Yuzhong which is slightly polluted in Lanzhou city, the concentration of heavy metals attached on particulate matters in different seasons and different regions is measured, and the distribution proportion of heavy metals in different diameters of particulates is analyzed. Based on the health risk evaluation model recommended by USEPA, this paper evaluates health risks of pollution caused by heavy metals on atmosphere particulates at different sampling places in Lanzhou city. The result shows that heavy metal attached on particulate matter in Lanzhou city is distributed seasonally and regionally. Heavy metals on particulate matters in Lanzhou city are mainly attached on particulates of which the diameters are less than 10μm(PM10). In terms of horizontal gradient, the hazard index of heavy metal in the total suspension particulates in severely-polluted district of Lanzhou city in winter is greater than 1. In terms of vertical gradient, the hazard index of heavy metals on total suspension particulates 15m above ground in winter is greater than 1. These polluted aspects should be treated. The carcinogenic risk of chromium exceeds 10-6~10-4which is acceptable scope stipulated by USEPA and should be well handled.
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Li, Ming Di, Zhong Wang, Shu Ai Liu, Rui Na Li, and Yang Zhao. "Study on the Particulate Microstructure of Different Oxygenated Fuels." Advanced Materials Research 726-731 (August 2013): 1950–53. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1950.
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The microstructures of particulates fueled with ethanol/diesel, DMC/diesel, and biodiesel/diesel blends were studied using the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of oxygenated fuels on the microstructures of particulates were studied. The results showed that the particulates presented with chain and group like structures. The particulate size was approximately following the normal distribution. With the increase of oxygenated fuels blends ratios, the extent of agglomeration increased and the structure arrangement became closer.
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Roman, Monika, Kamil Roman, and Michał Roman. "Spatial Variation in Particulate Emission Resulting from Animal Farming in Poland." Agriculture 11, no. 2 (February 19, 2021): 168. http://dx.doi.org/10.3390/agriculture11020168.
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The article presents a spatial variation in particulate emission from animal farming in Poland. In addition, this paper estimates the PM2.5 and PM10 particulate emissions. The data on respective emissions sources have been acquired from the Central Statistics Authority (GUS) of 2019 (Local Data Bank). The emissions of PM2.5 and PM10 particulates were estimated from the structure of the emissions sources covered in the “EEA/EMEP Emission Inventory Guidebook” following the Tier 1 method. The research shows that, in Poland, the biggest share in particulate emission is found for poultry and cattle farming, which are the emissions of 5.5 and 3 m kg of particulates annually all across Poland, respectively. The highest pollution with PM2.5 resulting from animal farming was recorded for the Podlaskie (0.19 kg/ha), Wielkopolskie (0.16 kg/ha), and Mazowieckie (0.14 kg/ha) provinces, whereas the highest pollution with PM10 was recorded for the Wielkopolskie province (0.83 kg/ha). The key sources of particulate emission indicated in the study facilitate adapting the adequate method to reduce the particulate emissions in respective provinces. It is essential, especially due to the negative effect of particulates on human health.
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Grimm, Christian, Agnès Feurtet-Mazel, Oleg S. Pokrovsky, and Eric H. Oelkers. "Riverine Particulate Matter Enhances the Growth and Viability of the Marine Diatom Thalassiosira weissflogii." Minerals 13, no. 2 (January 26, 2023): 183. http://dx.doi.org/10.3390/min13020183.
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Riverine particulates dominate the transport of vital nutrients such as Si, Fe or P to the ocean margins, where they may increase primary production by acting as slow-release fertilizer. Furthermore, the supply of particulate surface area to the ocean is considered to be a major control of organic carbon burial. Taken together, these observations suggest a close link between the supply of riverine particulate material and the organic carbon cycle. To explore this link, we conducted microcosm experiments to measure the growth of the marine diatom Thalassiosira weissflogii in the presence and absence of different types and concentrations of riverine particulate material. Results demonstrate a strong positive effect of riverine particulate material on diatom growth with increased total diatom concentrations and slowed post-exponential death rates with increasing particulate concentration. Moreover, SEM and optical microscope investigations confirm that riverine particulates facilitate organic carbon burial through their role in the aggregation and sedimentation of phytoplankton. The supply of riverine particulate material has been shown to be markedly climate sensitive with their fluxes increasing dramatically with increasing global temperature and runoff. This pronounced climate sensitivity implies that riverine particulates contribute substantially in regulating atmospheric CO2 concentrations through their role in the organic carbon cycle.
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Patel, Murlidhar, Sushanta Kumar Sahu, and Mukesh Kumar Singh. "Fabrication and Investigation of Mechanical Properties of SiC Particulate Reinforced AA5052 Metal Matrix Composite." Journal of Modern Materials 7, no. 1 (July 6, 2020): 26–36. http://dx.doi.org/10.21467/jmm.7.1.26-36.
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In this present research particulate reinforced aluminium metal matrix composites are developed by using sand mould and liquid stir casting processing route in which AA5052 reinforced with 5 wt. % SiC particulates of 63µm particle size. The density, porosity, micro-hardness, and compressive strength of SiC particulate reinforced AA5052 MMC were investigated and compared these properties with similar properties of unreinforced AA5052. The microstructure of the developed composite was also analysed by using optical microscopy, SEM, and XRD. Developed particulate reinforced Al metal matrix composite gives improved hardness and compressive strength as compared to the unreinforced AA5052. The addition of 5 wt. % SiC particulates increases the density of AA5052.
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Wang, Hong Ming, Gui Rong Li, Yu Tao Zhao, and Zhao Zhang. "Effect of Combined Electromagnetic Field on Microstructure and Surface Quality of (Al2O3+Al3Zr)P/Al Composites." Advanced Materials Research 152-153 (October 2010): 1387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.1387.
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In the experiment Al-Zr(CO3)2 components were utilized to in situ synthesize the Al2O3, Al3Zr reinforced aluminum matrix composites. Low frequency and high frequency electromagnetic fields were combined and introduced into the fabrication of particulates reinforced aluminum matrix composites. The average size of particulate and grain size of matrix were refined to 0.5~1μm and 20~40μm separately. The particulates distributed uniformly in matrix. The Lorenz force improved the kinetic condition and accelerated the nucleation of endogenetic particulates. At the meniscus of solidifying billet the high frequency electromagnetic field was applied. The surface quality of billet was enhanced obviously.
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Molik, Artur, Marzena Trojanowska, Monika Łożyńska, and Ryszard Świetlik. "Seasonal variations in chromium concentration in urban atmospheric aerosol in the city of Radom." E3S Web of Conferences 28 (2018): 01024. http://dx.doi.org/10.1051/e3sconf/20182801024.
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This paper presents seasonal variations in the occurrence of chromium in urban particulate matter (PM). Radom is an interesting area for this type of research due to its typical antiquated heating infrastructure. PM samples of two particulate fractions PM2.5 (particulates ≤ 2.5 µm) and PM10 (particulates ≤ 10 µm) were collected using a Copley cascade impactor Hi-Flow MOUDI Model 130. Chromium was determined in the samples using the GF-AAS technique. The concentration of chromium in PM2.5 was in the range of 0.38 to 3.2 ng/m3, whereas in PM10 it ranged from 0.43 to 4.1 ng/m3.
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Ramraji, K., K. Rajkumar, and P. Sabarinathan. "Tailoring of tensile and dynamic thermomechanical properties of interleaved chemical-treated fine almond shell particulate flax fiber stacked vinyl ester polymeric composites." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 11 (May 9, 2019): 2311–22. http://dx.doi.org/10.1177/1464420719849616.
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Natural fiber and particulates are being exploited to attain eco-friendly products for construction and automotive sectors. These sectors are moving towards the use of high damping characteristic natural biofibers and particulate-reinforced polymer composite as part of the structural components. In this work, woven flax fiber (0° and 90°) and almond shell particulates were used. They were subsequently treated with alkaline and acetylene chemical solution separately. Polymer composite laminates were prepared using a vinyl ester resin as matrix and by stacking flax fibers and almond particulates interleaved in an alternative sequence using the hand layup technique. This was followed by hydraulic pressing. Composite laminates were fabricated by varying the almond shell particulate weight fraction of 0%, 5%, 10%, and 15%. Mechanical properties such as tensile and flexural strength were experimentally measured. Dynamic thermomechanical analysis was conducted on the alkaline-treated and untreated composites with different frequencies for the assessment of the damping characteristics. The alkaline-treated interleaved almond shell and flax fiber composite showed considerably higher damping characteristics. This could be due to the improved adhesion between the matrix and reinforcements. An addition of almond shell particulate positively increased the strength and stiffness of composites.
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Yu, Hong, Mary Sue Brewer, Karen K. Leonas, James A. Knopp, and Patricia A. Annis. "Evaluation of a robotic transfer replicator: machine parameters that affect measurements of transfer of particulates from carpet surfaces to human skin versus human skin-like surfaces." Textile Research Journal 88, no. 19 (July 22, 2017): 2234–49. http://dx.doi.org/10.1177/0040517517718191.
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We have designed and built a robotic machine (robotic transfer replicator) to replicate the process by which various particulates are transferred from carpet surfaces to human skin. The particulates tested included bovine serum albumin, dust mites, paint dust, pesticides, and pollen. We have investigated the effect of time of transfer, applied pressure, skin-like receptor materials, particulate size, carpet composition and construction, and motion of the receptors on the percent transfer. The amount transferred was determined to be directly proportional to the amount of particulate applied to the carpet surface. The percent transfer values ranged from 0.05% to 28% for different combinations of particulates, carpet types, and method of transfer. The percent transfer was shown to be independent of receptor size or applied pressure. To explain the variations in the percent transfer, a three-zone model for particulate penetration into carpets is proposed. While the robotic transfer replicator was not capable of reproducing exactly the results from human finger transfer, it does provide a controlled and reproducible approach to the transfer process and the ability to use toxic or pathogenic materials that could not be used with human subjects.
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Cao, Yong, Da Di Zhang, Jing Liu, and Dan Yu. "The Horizontal and Vertical Distribution of Particulates in a Near-Road Environment." Advanced Materials Research 1065-1069 (December 2014): 3215–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.3215.
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The distribution of particulate matters is now receiving significant attention given their role in human health and respiratory related diseases. The concentrations of PM10, PM2.5 and PM1.0 were measured in different test points near the road. Two sampling campaigns were conducted in this study. The results indicated that a gradual decrease in the concentrations of particulate matters with distance from the edge of the road. The concentrations of these particulates decreased with the increase of height when the sites were under trees or other vegetations, while the concentrations of these particulates increased with the increase of height when the sites were higher than the height of trees or other vegetations.
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Fan, Hui. "Electroplating of Compound Ni–SiC Coatings and Improvement of Wear Resistance." Key Engineering Materials 426-427 (January 2010): 399–402. http://dx.doi.org/10.4028/www.scientific.net/kem.426-427.399.
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Ni-SiC nano-composite coatings with various contents of SiC nano-particulates were prepared by means of the conventional electrodeposition in a nickel-plating bath containing SiC nano-particulates to be co-deposited. The surface morphology and structural constituent in the electrolyte layer were observed by SEM and EDS. The dependence of SiC nano-particulates amount in the nano-composite coatings was investigated in relation to the SiC concentration in bath. The effect of SiC nano-particulate incorporation content on micro-hardness as well as wear-resistance was studied too. The results showed that the nano-Ni-SiC plating layer had smooth and flat surface, uniform microstructure as well as higher micro-hardness and wear-resistance than pure Ni coating. The optimum experimental parameters were derived at condition of, addition of 6g/L SiC nano-particulates in the bath, 40°C temperature, current density of 4A/dm2 , and a stirring rate of 250rpm.
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Williams, Mark. "Particulates." Hudson Review 40, no. 4 (1988): 620. http://dx.doi.org/10.2307/3851135.
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Zhong, Li Sheng, Yun Hua Xu, Na Na Wang, Xiao Jie Liu, Fang Xia Ye, and Shan Shan Hu. "Infiltration Casting and In Situ Fabrication of NbC Particulates – Reinforced Iron Matrix Composites." Advanced Materials Research 284-286 (July 2011): 269–72. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.269.
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Niobium carbide (NbC) particulates -reinforced iron matrix composites were prepared by in- situ fabrication method combining an infiltration casting with a subsequent heat treatment. The microstructure and wear-resistance of NbC particulate-reinforced iron matrix composites were studied using scanning electron microscopy, X-ray diffraction, and wear testing. The results indicate that at 1172 °C for 3 hours NbC particulate-reinforced iron matrix composites were fabricated, and the size of NbC reinforcement was 0.3–3.5 μm. The relative wear resistance of the composites was 5.4 times higher than that of gray cast iron under a 20 N load. This was achieved at 22 % NbC volume fraction. Wear of the composites manifests as grooves, broken carbide particulates and some micro-cracks.
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Saenz, Natalio, Heather Dillon, Shelley Carlson, and Gary Maupin. "Advanced Metallographic Techniques Applied to Diesel Particulate Filters." Microscopy Today 15, no. 5 (September 2007): 44–45. http://dx.doi.org/10.1017/s1551929500061253.
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Diesel Particulate Filters (DPFs) are designed to capture exhaust particulates from engines. The filter material collects the particulates deep in the substrate (deep-bed filtration) before transitioning to other filtration methods on the surface. The deep-bed filtration has been characterized by modeling studies but little experimental information about the particulate, or soot, penetration in the filter material is available. Traditional evaluation methods do not provide sufficient contrast between the soot and mounting resins.Due to the difficulty of locating carbon soot in the pores in these filters, ultra-thin section techniques (under 10-micron-thick sections) were used for the characterization of these samples. Under transmitted light, the carbon soot is black because it blocks the light, and the carbon in the resin material is relatively clear.
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Robinson, Timothy M., Paul A. Manley, Paul A. Sims, Ralph Albrecht, and Benjamin J. Darien. "Cytokine and Eicosanoid Production by Cultured Human Monocytes Exposed to Titanium Particulate Debris." Microscopy and Microanalysis 5, no. 5 (September 1999): 344–51. http://dx.doi.org/10.1017/s1431927699000173.
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Phagocytosis of particulate wear debris from arthroplasties by macrophages induces an inflammatory response that has been linked to implant loosening and premature failure of artificial joints. Inflammatory mediators released by phagocytic macrophages such as tumor necrosis factor-a (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) are believed to play a central role in the pathogenesis of aseptic loosening. The objective of this study was to characterize titanium alloy particulates that closely match wear debris found around joint arthroplasties and to study their effects on the biosynthesis of inflammatory mediators by cultured monocytes. Peripheral blood monocytes were isolated from healthy human volunteers. Monocytes were cultured in 96-well plates for 24 h, washed, and exposed to three concentrations of titanium particulates and controls from 18Ð24 h. Supernatants were assayed for TNF-α, IL-1β, IL-6, and PGE2 activity. Energy dispersive X-ray spectroscopy (EDX) verified the titanium alloy to be Ti6A14V. Scanning electron microscopy (SEM) analysis showed significant titanium particulate heterogeneity with approximately 95% of the particles <1 micrometer in diameter. SEM and EDX technology was useful in the characterization of the titanium particulates utilized for in vitro models of titanium-induced cytokine release by monocytes. Incubation of titanium particulates (in concentrations similar to those found around loosened prosthetic joints) with cultured monocytes significantly increased their production of TNF-α, IL-1β, and PGE2.
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Lu, Mei Fang, Mei Chuan Huang, Kuang Hung Cheng, and Jim Jui Min Lin. "Size and Composition of Ambient Particulates in the Yueguangshan-Tunnel, Taiwan." Advanced Materials Research 726-731 (August 2013): 2074–78. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.2074.
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The aim of this study is to investigate the characteristics of size distribution and chemical composition of ambient particulates inside a tunnel. Inside the tunnel, the average concentration of PM2.5and PM2.5-10was 479 and 444 μg/m3respectively. The average mass-size distribution showed a trimodal distribution (25-30, 4.0-5.0, and 2.5, PM2.5-10, and PM>10were 25%, 40%, and 35% of the total suspended particulates. Because of the poor air ventilation inside the tunnel, the particulates accumulate inside the tunnel. The dominated species of PM2.5were EC (average concentration 122.91 μg/m3, 25.78%), OC (47.68 μg/m3, 10.53%), SO42-(37.42 μg/m3, 8.24%), and NO3-(35.01 μg/m3, 7.95%), and were EC ( 131.77 μg/m3, 29.87%), OC (53.74 μg/m3, 12.15%), SO42-(31.35 μg/m3, 7.11%), and NO3-(28.10 μg/m3, 6.42%) for PM2.5-10. Results from this study showed that the concentrations of coarse particulate matter and several metals are apparently dominated by re-suspended matter rather than emissions from vehicles, e.g., Al, Ca, and Fe. Therefore, ambient particulate matter is caused by not only vehicle exhaust emission but also dusty roads and traffic-generated dust.
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Cha, Yingying, Saeed Abbasi, and Ulf Olofsson. "Indoor and outdoor measurement of airborne particulates on a commuter train running partly in tunnels." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 1 (April 7, 2016): 3–13. http://dx.doi.org/10.1177/0954409716642492.
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Wear processes from mechanical braking, rail/wheel contact, the railway electrification system and re-suspended materials due to the turbulence of passing trains in tunnels and stations have been suggested to be the main contributors to particulate matter levels inside trains. In this study, onboard monitoring was performed on a commuter train stopping at underground and aboveground stations. The concentration and size distribution of particulates were monitored for both indoor and outdoor levels. The results show that the levels of PM10 and PM2.5 inside the train were about one-fifth of the outdoor levels. Significant increases in indoor particulate number concentrations were observed in tunnel environments and there was a slight increase when the doors were open. Differences in the size distributions of micro- and nano-sized particulates could be identified for different tunnels.
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Huboyo, Haryono S., and Sudarno Sudarno. "Analysis of Particulates and SO2 Removal from Coal Combustion Emissions Using Cyclone and Wet Scrubber With Textile Wastewater Feed." TEKNIK 41, no. 3 (November 30, 2020): 239–45. http://dx.doi.org/10.14710/teknik.v41i3.33883.
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Reuse of wastewater in the industry is mostly accomplished for watering plants. In a closed cycle, however, industrial wastewater can be returned through treatment to save water usage. This study aims to analyze textile wastewater's ability to be used as scrubbing liquid in the SO2 gas and particulate removal from coal combustion using a packed wet scrubber. Usually, the textile industry uses boiler fueled by coal and discharging base/alkaline wastewater. The method is carried out experimentally using a prototype device using a combination of cyclone and scrubber, with a source of coal combustion gas emissions. We did experiments using textile wastewater four times and two times using clean water as a control. We monitor the SO2, particulate emission in the gas stream, and pH, sulfate levels, and TSS levels in collected wastewater according to SNI. SO2 gas and particulates from coal combustion will be absorbed by the scrubber's wastewater spray so that SO2 will dissolve into sulfate, particulate matter into TSS. The study results using textile wastewater showed the removal efficiency of particulates on cyclone by 34-78%. The removal efficiency of SO2 on wet scrubber was only 24.7%. There was an increase in TSS levels after passing through the scrubber by 46%. The rise in TSS and sulfate concentrations in the wastewater indicates the absorption of SO2 and particulates into wastewater. Based on this result, we can use textile wastewater for controlling the emission of SO2 and particulate from coal combustion by feeding it for the scrubber. However, the efficiency of this process is not optimal.
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Suraya, Sulaiman, Shamsuddin Sulaiman, Ali Munira, and Abdul Aziz Fazilah. "Effect of TiC Particulates on the Microstructure and Mechanical Properties of Aluminium-Based Metal Matrix Composite." Advanced Materials Research 903 (February 2014): 145–50. http://dx.doi.org/10.4028/www.scientific.net/amr.903.145.
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In this research, metal-matrix composites (MMCs) of aluminium-11.8% silicon alloy matrix reinforced with titanium carbides particulates were fabricated by the casting technique. Aluminium-11.8% silicon alloy is selected as the matrix material and titanium carbide as particulates are mixed in different weight percentages, 5%, 10%, 15% and 20%wt. The cylinder composite castings are made by pouring the composite mixture in copper permanent-molds. The microstructure and mechanical properties of these composite materials were investigated. The effects of reinforced materials on weight percentages addition of particulate on the particulate distribution in aluminium-11.8% silicon alloy composites and SEM observation of the fracture surfaces of tensile tested specimens were deliberate. Moreover, cylinder castings without particulate addition are made and compared with the result based on the properties and microstructural features. It is found that the microstructure and mechanical properties of composites significantly improved by the use of particle reinforced into aluminium alloy.
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Springer, K. J. "Diesel Lube Oils—Fourth Dimension of Diesel Particulate Control." Journal of Engineering for Gas Turbines and Power 111, no. 3 (July 1, 1989): 355–60. http://dx.doi.org/10.1115/1.3240261.
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Particulate emission control, for the HD diesel engine, has previously been considered a three-dimensional problem involving: (1) combustion of the fuel by the engine, (2) fuel modification, and (3) exhaust aftertreatment. The lube oil contribution may be considered a fourth dimension of the problem. Historically, the heavy-duty engine manufacturer has met emission standards for smoke (1968 to present), CO, HC, and NOx (1974 to present) and particulates (1988 to present) through changes in engine design. This paper uses the allocation method to estimate the reduction in lube oil consumption needed to meet 1991 and 1994 U.S. particulate emission standards. This analysis places the contribution of lube oil as a source of exhaust particulates into prospective with the contributions from fuel sulfur and fuel combustion. An emissions control strategy to meet future regulations is offered in which reductions from fuel modification, combustion improvement, reduced lube oil consumption, and exhaust particulate trap-catalysts are all involved.
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Emura, Satoshi, and Masuo Hagiwara. "Effect of Heat Treatment on the Creep Properties of Ti-22Al-27Nb/TiB Composite." Key Engineering Materials 345-346 (August 2007): 545–48. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.545.
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A TiB particulate-reinforced Ti-22Al-27Nb (mol%) alloy, based on the orthorhombic intermetallic phase, was prepared using gas atomization powder metallurgy method. In the as-atomized condition, extremely fine TiB particulates of less than 1-μm diameter and 5-μm length were dispersed in the matrix. After annealing heat treatment (heat treated at 1423 K with subsequent furnace cooling), this composite exhibited a lamellar matrix microstructure and showed better creep properties than a composite produced using conventional ingot metallurgy method, with coarse TiB particulates of 5-μm diameter and 40-μm length. Coarsening of the matrix microstructure and growth of TiB particulates occurred after annealing heat treatment at higher temperature (ca. 1473 K). Creep-resistance improvement was also observed, which seemed to be mainly attribute to the effect of the matrix microstructure. From measurements of stress components and activation energy, all composites showed an identical creep mechanism: dislocation-controlled creep.
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Lurton, T., J. B. Renard, D. Vignelles, M. Jeannot, R. Akiki, J. L. Mineau, and T. Tonnelier. "Light scattering at small angles by atmospheric irregular particles: modelling and laboratory measurements." Atmospheric Measurement Techniques 7, no. 4 (April 7, 2014): 931–39. http://dx.doi.org/10.5194/amt-7-931-2014.
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Abstract. We have investigated the behaviour of light scattering by particulates of various sizes (0.1 μm to 100 μm) at a small scattering angle (below 20°). It has been previously shown that, for a small angle, the scattered intensities are weakly dependent upon the particulates' composition (Renard et al., 2010). Particles found in the atmosphere exhibit roughness that leads to large discrepancies with the classical Mie solution in terms of scattered intensities in the low angular set-up. This article focuses on building an effective theoretical tool to predict the behaviour of light scattering by real particulates at a small scattering angle. We present both the classical Mie theory and its adaptation to the case of rough particulates with a fairly simple roughness parameterisation. An experimental device was built, corresponding to the angular set-up of interest (low scattering angle and therefore low angular aperture). Measurements are presented that confirm the theoretical results with good agreement. It was found that differences between the classical Mie solution and actual measurements – especially for large particulates – can be attributed to the particulate roughness. It was also found that, in this low angular set-up, saturation of the scattered intensities occurs for relatively small values of the roughness parameter. This confirms the low variability in the scattered intensities observed for atmospheric particulates of different kinds. A direct interest of this study is a broadening of the dynamic range of optical counters: using a small angle of aperture for measurements allows greater dynamics in terms of particle size. Thus it allows a single device to observe a broad range of particle sizes whilst utilising the same electronics.
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Shukla, Pravesh Chandra, Tarun Gupta, Nitin Kumar Labhsetwar, and Avinash Kumar Agarwal. "Development of low cost mixed metal oxide based diesel oxidation catalysts and their comparative performance evaluation." RSC Advances 6, no. 61 (2016): 55884–93. http://dx.doi.org/10.1039/c6ra06021h.
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A four cylinder diesel engine was used to evaluate the performance of two non-noble metal based diesel oxidation catalysts for emission parameters such as particulate mass, elemental/organic carbon (EC/OC), and trace-metal content in particulates.
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Babalola, Saheed Adeoye, Kenneth Kanayo Alaneme, Samuel Ranti Oke, Lesley Heath Chown, Nthabiseng Beauty Maledi, and Michael Oluwatosin Bodunrin. "Hot compression behaviour and microstructural evolution in aluminium based composites: an assessment of the role of reinforcements and deformation parameters." Manufacturing Review 8 (2021): 6. http://dx.doi.org/10.1051/mfreview/2021004.
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The response of two different types of aluminium matrix composites (AMCs) reinforced with silicon carbide ceramic particulates or nickel metallic particulates to hot compression testing parameters was evaluated. The composites were produced via two-step stir-casting technique. Axisymmetric compression testing was performed on the samples at different deformation temperatures of 220 and 370 °Ϲ, 0.5 and 5 s−1 strain rates and total strains of 0.6 and 1.2. The initial and post-deformed microstructures were studied using optical and scanning electron microscopy. The results show that flow stress was significantly influenced by imposed deformation parameters and the type of reinforcements used in the AMCs. Nickel particulate reinforced aluminium matrix composite (AMC) showed superior resistance to deformation in comparison with silicon carbide reinforced AMC under the different testing conditions. In both AMCs, work hardening, dynamic recovery and dynamic recrystallisation influenced their response to imposed parameters. The signature of dynamic recrystallisation was very apparent in aluminium matrix composite reinforced with nickel particulates.
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Dorscheidt, Frank, Stefan Pischinger, Johannes Claßen, Stefan Sterlepper, Sascha Krysmon, Michael Görgen, Martin Nijs, Pawel Straszak, and Abdelrahman Mahfouz Abdelkader. "Development of a Novel Gasoline Particulate Filter Loading Method Using a Burner Bench." Energies 14, no. 16 (August 11, 2021): 4914. http://dx.doi.org/10.3390/en14164914.
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In view of the deliberations on new Euro 7 emission standards to be introduced by 2025, original equipment manufacturers (OEMs) are already hard at work to further minimise the pollutant emissions of their vehicles. A particular challenge in this context will be compliance with new particulate number (PN) limits. It is expected that these will be tightened significantly, especially by including particulates down to 10 nm. This will lead to a substantially increased effort in the calibration of gasoline particulate filter (GPF) control systems. Therefore, it is of great interest to implement advanced methods that enable shortened and at the same time more accurate GPF calibration techniques. In this context, this study presents an innovative GPF calibration procedure that can enable a uniquely efficient development process. In doing so, some calibration work packages involving GPF soot loading and regeneration are transferred to a modern burner test bench. This approach can minimise the costly and time-consuming use of engine test benches for GPF calibration tasks. Accurate characterisation of the particulate emissions produced after a cold start by the target engine in terms of size distribution, morphology, and the following exhaust gas backpressure and burn-off rates of the soot inside the GPF provides the basis for a precise reproduction and validation process on the burner test bench. The burner test bench presented enables the generation of particulates with a geometric mean diameter (GMD) of 35 nm, exactly as they were measured in the exhaust gas of the engine. The elemental composition of the burner particulates also shows strong similarities to the particulates produced by the gasoline engine, which is further confirmed by matching burn-off rates. Furthermore, the exhaust backpressure behaviour can accurately be reproduced over the entire loading range of the GPF. By shifting GPF-related calibration tasks to the burner test bench, total filter loading times can be reduced by up to 93%.
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Shetty, Raviraj, Prakash Rao Gurupur, Jamaluddin Hindi, Adithya Hegde, Nithesh Naik, Mohammed Sabraz Sabir Ali, Ishwargouda S. Patil, and Madhukar Nayak. "Processing, Mechanical Characterization, and Electric Discharge Machining of Stir cast and Spray Forming-Based Al-Si Alloy Reinforced with ZrO2 Particulate Composites." Journal of Composites Science 6, no. 11 (October 26, 2022): 323. http://dx.doi.org/10.3390/jcs6110323.
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High performance lightweight structures made of metal matrix composites (MMCs) are in demand for application in variety of industries such as aircraft, spacecraft, automobile, marine, sports equipment, etc. However, uniform distribution of the reinforcement phase to improve the mechanical properties and quality of MMCs has been the challenge for the manufacturing industries. Hence, researchers are focusing on the development of traditional low-cost method of producing metal matrix composites. In the view of above facts, an attempt is made to study the processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites in this paper. Hence, this paper concentrates on experimentally identifying the effect of stir cast and spray forming processing techniques followed by hot pressing on micro hardness, compressive strength, and tensile strength using Taguchi’s design of experiments for aluminum silicon matrix alloy reinforced with zirconium dioxide particulates. From the extensive experimentation on aluminum and silicon reinforced with the ZrO2 powder particulates, it was observed that there was an improvement in selected mechanical properties as the percentage of ZrO2 increased with 13 wt.% of silicon under spray forming processing technique compared to stir cast composites. This may be due to uniform distribution homogenous dispersion, larger work hardening rate, and structure of dislocation tangles around the ZrO2 particulates that occurred during spray forming processing technique. Further, results obtained from the interaction plot, contour plot, main effects plot, and analysis of variance (ANOVA) proved to be successful for identifying the optimum processing parameters for Si-Al alloy reinforced with zirconium dioxide particulate composites. Further, this paper also discusses wear study using pin on disc wear testing apparatus on spray forming processed aluminum and silicon (13.0 wt.%) alloy reinforced with the ZrO2 powder particulates based on Taguchi’s design of experiments followed by second order model generation for wear using response surface methodology. Finally, electrode wear study of spray forming processed aluminum and silicon alloy reinforced with the ZrO2 powder particulates using electric discharge machining by varying peak current (A), pulse on time (μs), and pulse off time (μs) using brass, copper, and graphite as electrode material based on L27orthogonal array. The understanding gained from the design of experiments in this paper can be used to develop future guidelines for processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites.
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Dong, Y. S., C. Guo, Ping Hua Lin, L. H. Yin, and Yong Ping Pu. "Preparation of Porous Poly (L-Lactic Acid) (PLLA) Scaffold by Porogen Leaching and Freeze Drying." Key Engineering Materials 288-289 (June 2005): 381–84. http://dx.doi.org/10.4028/www.scientific.net/kem.288-289.381.
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The poly (L-lactic acid) (PLLA) porous scaffolds were prepared by porogen leaching combined freeze drying with the porogen particulates of ice in this paper. The ice particulates are made of distilled water sprayed into liquid nitrogen through a nozzle under a certain pressure. The pore morphology, porosity and residual porogen of the scaffolds was studied. There is no residual porogen when the ice particulate is used and the leaching mechanism of porogen is discussed. The scaffolds are composed of macro and micro pores and with a porosity of 80-90%. The macro pores are formed by ice particulate and the micro pores by thermal induced phase separation of solvent. The pore size can be changed easily by altering the size of ice particulate. The MTT assay was used to estimate cellular activity by L-929 cells culture in vitro. The results demonstrate that the scaffolds have no cytotoxicity. It could confidently be stated that the combined process seems to be a promising technique for the fabrication of porous polymer scaffold.
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Blanuša, Tijana, Zeenat Jabeen Qadir, Amanpreet Kaur, James Hadley, and Mark B. Gush. "Evaluating the Effectiveness of Urban Hedges as Air Pollution Barriers: Importance of Sampling Method, Species Characteristics and Site Location." Environments 7, no. 10 (October 1, 2020): 81. http://dx.doi.org/10.3390/environments7100081.
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Urban hedgerows can act as barriers to roadside particulate air pollution, but details on methodologies to quantify pollutant capture, most efficient species to use, and practical planning advice are still evolving. We aimed to compare three widely used approaches to quantify particulate accumulation and deposition, and to ascertain the most cost-effective and robust approach for the rapid screening of various types of hedges. Secondly, using the most efficient methodology, we screened the summertime deposition of particulates on roadside hedges in Reading (UK), not just on species with differing leaf surface characteristics, but also along a transect of the hedge depth. Finally, we also compared particles’ capture by hedge leaf surfaces in locations with different traffic intensities, to try and ascertain the extent of reduction of particles’ concentration in various hedge types and urban locations. Results suggest that the gravimetric determination of particulate capture was most rapid and cost-effective, while being least technically demanding. We confirmed that hairy and more complex leaves captured most particulates, particularly in the >10 μm range. However, species choice only had a significant impact on the extent of capture on major roads, where the pollutant concentrations were highest. Furthermore, only hedge depths in excess of 2 m were found to noticeably reduce the concentration of fine particles in species with less capacity for particulates’ capture. Findings complement the growing body of knowledge to guide urban and landscape planners in choosing the most appropriate species to mitigate air quality in various urban contexts.
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Suhana, J., and M. Rashid. "Evaluation of Radiological Hazards of Particulates Emissions From a Coal Fired Power Plant." Chemical Product and Process Modeling 11, no. 3 (September 1, 2016): 197–203. http://dx.doi.org/10.1515/cppm-2015-0073.
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Abstract Natural minerals may contain radionuclides of natural origin of Uranium-238 (238U) and Thorium-232 (232Th) decay series. Similarly, coal like any other minerals found in nature contains trace amount of such naturally occurring radionuclides including Potassium-40 (40K). The generation of electricity by coal fired power plant (CFPP) releases particulates emission to the atmosphere and deposited on the surrounding area that may increase the natural background radiation level within the facility. This paper presents an evaluation of the natural radioactivity concentration found in the particulates emission from a typical CFPP in Malaysia. Standard Gaussian dispersion model approach was used to predict the potential radiological hazards arising from the particulates released from the stack. The predicted maximum ground level particulate (Cmax) concentration and downwind distance (X) was 52 µg m–3 and 1,600 m of away from the CFPP, respectively. The air dispersion modelling results recorded that the calculated Cmax released from the CFPP was found lower than the national and international ambient air quality limits, which means that radiological hazards due to inhalation of natural radionuclides in particulate released to the environment is insignificant. The findings revealed that, this activity does not impose any significant radiological risk to the human population at large and the operation is in compliance with the national legislation and international practice.
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Parkash, Om, Arvind kumar, and Basant Singh Sikarwar. "CFD modeling of slurry flow erosion wear rate through mitre pipe bend." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 236, no. 5 (January 5, 2022): 2256–67. http://dx.doi.org/10.1177/09544062211026353.
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Erosive wear caused by particulates slurry is one of the major concerns in the pipe bend which may results in the failure of the pipe flow system. In the present work, erosion wear rate through mitre pipe bend caused by silica sand particulates slurry has been investigated using ANSYS Fluent code. The solid spherical particulates of size 125 µm and 250 µm having density of 2650 Kg/m3, were tracked to compute the erosion wear rate using Discrete Phase Method (DPM) model. The particulates were tracked using Eulerian-Lagrange approach along with k-ɛ turbulent model for continuous fluid phase. The silica particulates were injected at solid concentration of 5% and 10% (by weight) from the pipe inlet surface for wide range of velocities viz. 1–8 ms−1. The erosion wear rate was computed through four computational erosion models viz. Generic, Oka, Finnie and Mclaury. Furthermore, the outcomes obtained through Generic models are verified through existing experimental data in the literture. Moreover, the results of DPM concentration, turbulence intensity and particle tracking were predicted to analyze the secondary flow behaviour through the bend cross section. Finally, the effect of particulate size, solid concentration and flow velocity were discussed on erosion wear rate through bend cross section. The findings show that the locality of maximum erosive wear is positioned at the extrados of the bend outlet cross section. Additionally, it is found that Mclaury model offers higher erosion rate as compared to the other models and provides benchmark for designing the slurry pipeline system.
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OKEDERE, OYETUNJI BABATUNDE, ADEWOLE JOHNSON ADESANMI, JACOB ADEMOLA SONIBARE, OLUSOLA ADEDAYO ADESINA, and GBADEBO OMONIYI ADENIYI. "TOTAL SUSPENDED PARTICULATES FROM CRUDE OIL SPILL." Journal of Engineering Studies and Research 27, no. 4 (December 15, 2021): 53–59. http://dx.doi.org/10.29081/jesr.v27i4.299.
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Total suspended particulates emitted during crude oil spill were investigated using laboratory simulation experiments. This was with a view to establishing the toxicity potentials of emitted particulates. Climatic and spill media conditions similar to those obtainable in real life were created in an environmental chamber and the total particulates emitted during spills involving three crude oil samples of Nigerian origin were measured with Quick Take sampler. The toxicity potentials of the emitted particulates were subsequently determined by dividing the 24- hour averaging period concentrations of the particulates by the statutory limit. The statutory limits used were those of Nigeria’s Federal Ministry of Environment (FMENV), World Bank and the World Health Organization (WHO). For temperatures between 15 ºC and 35 ºC and spill media (over fresh water, sea water and soil), the extrapolated 24 – hour averaging period concentrations ranged between 186.79 – 584.28 μgm-3, 186.98 - 584.48 μgm-3 and 247.40- 350.21 μgm-3 for sample A; 183.44 – 571.99 μgm-3, 183.63 -572.19 μgm-3 and 244.05-337.92 μgm-3 for sample B and 178.41 – 566.96 μgm-3, 178.61 - 567.16 μgm-3 and 332.89- 280.60 μgm-3 for sample C. The observed TSP concentrations breached the WHO (lower limit) and World Bank limits at all temperatures and over all spill media and consequently the toxicity potentials exceeded 1.0 which were indications of hazards to human health. The study concluded that particulate emissions during crude oil could be high enough to pose threats and suggested adequate protection for cleaning up workers.
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Jordan, J. L., J. E. Spowart, M. J. Kendall, B. Woodworth, and C. R. Siviour. "Mechanics of particulate composites with glassy polymer binders in compression." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2015 (May 13, 2014): 20130215. http://dx.doi.org/10.1098/rsta.2013.0215.
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Whether used as structural components in design or matrix materials for composites, the mechanical properties of polymers are increasingly important. The compressive response of extruded polymethyl methacrylate (PMMA) rod with aligned polymer chains and Al–Ni–PMMA particulate composites are investigated across a range of strain rates and temperatures. The particulate composites were prepared using an injection-moulding technique resulting in highly anisotropic microstructures. The mechanics of these materials are discussed in the light of theories of deformation for glassy polymers. The experimental data from this study are compared with PMMA results from the literature as well as epoxy-based composites with identical particulates. The PMMA exhibited the expected strain rate and temperature dependence and brittle failure was observed at the highest strain rates and lowest temperatures. The Al–Ni–PMMA composites were found to have similar stress–strain response to the PMMA with reduced strain softening after yield. Increasing volume fraction of particulates in the composite resulted in decreased strength.
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Yu, Hui, Hua Shun Yu, Zhen Ya Zhang, Guang Hui Min, and Cheng Chen. "Microstructural Evolution and Mechanical Properties of AZ91 and SiCp/AZ91 Magnesium Alloys upon Rapid Solidification/Powder Metallurgy Followed by Hot Extrusion." Advanced Materials Research 146-147 (October 2010): 734–37. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.734.
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In this study, AZ91 and SiC particulates reinforced AZ91 (SiCp/AZ91) magnesium alloys were successfully fabricated using rapid solidification/powder metallurgy technique followed by hot extrusion. Microstructural evolution and mechanical properties of the monolithic AZ91 and SiCp/AZ91 magnesium alloys were evaluated. SiC particulates were well distributed with only few agglomerated particles. The porosity level and microhardness increased as SiCp content increased because the increased surface area of SiCp, harder ceramic phases and SiCp acted obstacles to the motion of dislocations. In addition, an increase in particulate reinforcement content was observed to decrease mechanical properties of the composite compared with the unreinforced counterpart due to increasing agglomerating regions and porosity, brittle interface debonding between matrix and SiCp.
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Huimei, SHAN, LUO Linbo, WANG Shaopei, LIAO Danxue, ZHAO Chaoran, and PENG Sanxi. "Sources and Eco-toxicological Effects of Ultrafine Particle Matters." E3S Web of Conferences 136 (2019): 06008. http://dx.doi.org/10.1051/e3sconf/201913606008.
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Environmental air pollution has become an important threat to human health. As one of the major air pollutants, atmospheric particulates have received attention widely. In which, ultrafine particulate matters (UPM) with diameter below 0.1μm have become the main components of ambient air particulates, posing a serious threat to the health of the organism. Therefore, this paper investigated and summarized the research on ultrafine particles at home and abroad, systematically analysed the sources of UPM in ambient air, investigated its toxicological effects of ultrafine particles on the respiratory system, cardiovascular system, and central nervous system of organisms. This study will provide a theoretical reference for environmental air protection and pollution control in China.
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Payment, Pierre, Eric Morin, and Michel Trudel. "Coliphages and enteric viruses in the particulate phase of river water." Canadian Journal of Microbiology 34, no. 7 (July 1, 1988): 907–10. http://dx.doi.org/10.1139/m88-158.
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The present study was undertaken to determine if indigenous enteric viruses and coliphages are free or associated with suspended particulate matter in natural waters. River water was filtered on filters of decreasing porosities (100–0.25 μm) that were pretreated with detergent to eliminate viral adsorption while retaining particulates. This filtered water was refiltered in virus-adsorbing conditions to retain free viruses. The virus-adsorbing filter retained most of the enteric viruses (77.4%) and coliphages (65.8%), which indicated that these viruses were probably free or associated with particles with a diameter of less than 0.25 μm. These observations are important because in water treatment plants small particulates are often the most difficult to eliminate.
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Cusack, M., J. M. Arrieta, and C. M. Duarte. "Source Apportionment and Elemental Composition of Atmospheric Total Suspended Particulates (TSP) Over the Red Sea Coast of Saudi Arabia." Earth Systems and Environment 4, no. 4 (November 24, 2020): 777–88. http://dx.doi.org/10.1007/s41748-020-00189-z.
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AbstractThis work presents a comprehensive study on concentrations and elemental composition of total suspended atmospheric particulates for a semi-urban site on the Red Sea coast, and on-board a research vessel, which collected off-shore samples along the Red Sea. We conducted one of the most extended measurement campaigns of atmospheric particulates ever for the region, with continuous measurements over 27 months. The overall mean concentrations (± st. dev.) of TSP were 125 ± 197 µg m−3 for the permanent semi-urban site, and 108 ± 193 µg m−3 for the off-shore mobile site. The region is frequently severely impacted by both localised and widespread dust storms, which on occasion, can increase atmospheric particulate concentrations to levels above mg m−3 (> 1000 µg m−3). Median concentrations were not as variable between seasons, indicating a stable, permanent presence of atmospheric particulates independent of the time of year. The primary chemical elements contributing to particulate mass were Na, Ca, S, Al and Fe. We employed Positive Matrix Factorisation (EPA PMF v5.0.14) to identify different major sources of particulates, which were crustal, marine, fuel oil combustion/secondary sulphate and mixed anthropogenic. The crustal source was characterised by tracers Al, Fe, K, Mg and Sn, and was present to some extent in the other identified sources due to the permanent presence of dust particles in the atmosphere. The fuel oil combustion/secondary sulphate source was identifiable by the almost exclusive presence of S, and to a lesser extent V, emitted from oil combustion as primary emissions and also secondary sulphate formation following the release of S to the atmosphere. A mixed anthropogenic source was characterised by Zn, Ni, Cr, Cu and Pb, emitted from traffic, industry, power generation and water desalination. This study highlights that the natural sources of particulates in this desert region give rise to frequent episodes of extremely poor air quality, and this problem is compounded by significant emissions of anthropogenic pollution, which has an impact across the entire Red Sea basin. Further stringent measures should be adopted to improve air quality across the region and prevent long-term damage to the health of the local population and ecosystems.
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Sulfikar, Sulfikar, Gotot Junarto, Muhammad Ardhias Syam, Andi Zulfikar Efendy, Mohamad Sahrir, and Hilda Ningsih. "A Snapshot of Antibiotic Resistances in Air Particulate of a Provincial Capital City, Indonesia." Jurnal Kimia Valensi 8, no. 1 (May 10, 2022): 42–53. http://dx.doi.org/10.15408/jkv.v8i1.24559.
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Bacteria may become resistant to antibiotics due to gene mutation or adopting resistance genes from other bacteria via horizontal gene transfer. The existence of toxic substances to bacteria, such as antibiotics, biocides, and heavy metals, may influence the pathway into the genome. This study aimed to detect the presence of antibiotic-resistance bacteria in air particulates in Makassar - a provincial capital located in Indonesia with a low to moderate air quality index (AQI). We determined the correlations between antibiotic resistance (resistance rate, RR) and the heavy-metal concentrations in the air particulates. Air particulate samples were taken from seven locations in the summer (Dry Season: July - August 2019). We analyzed the concentration of As, Cu, and Zn of the air particulates and determined RR from presumptive Escherichia coli (E. coli) isolated from the air particulates. We estimated the RR towards five antibiotics with different mechanisms of action: amoxicillin-clavulanate, chloramphenicol, amikacin, norfloxacin, and trimethoprim. The concentrations of the heavy metals were relatively low, ranging from (µg/Nm3) 0.001 – 0.009 for As, 0.001 – 0.003 for Cu, and 0.007 to 0.783 for Zn. We observed different antibiotic resistance at various locations, ranging from 25% to 100% RR. While there were indications of possible antibiotic resistance patterns in the different areas sampled, the power of this perspective snapshot was insufficient to make statistically valid generalizations.
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Vijayan, Akhil Marayikkottu, and Deborah A. Levin. "Kinetic modeling of fractal aggregate mobility." Physics of Fluids 34, no. 4 (April 2022): 043315. http://dx.doi.org/10.1063/5.0086310.
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Although the mobility or transport parameters, such as lift drag and pitching moments for regular-shaped particulates, are widely studied, the mobility of irregular fractal-like aggregates generated by the aggregation of monomers is not well understood. These particulates which are ubiquitous in nature, and industries have very different transport mechanisms as compared to their spherical counterpart. A high-fidelity direct simulation Monte Carlo (DSMC) study of two fractal aggregates of different shapes or dimensions is undertaken in the slip and transitional gas regime to understand the underlying mechanism of gas-particle momentum transfer that manifests as the orientation-averaged mobility parameters of the particulates. The study specifically focuses on the viscous contribution of these parameters and develops a non-linear correlation for drag and lift parameters p and q obtained from DSMC by normalizing the axial and lateral forces. The drag parameter p predicted a monotonic increase in fractal particulate drag with respect to a spherical monomer while the lift parameter q shows an initial increasing trend but a decreasing tendency toward the high Mach number or high compressibility regime. The approximate model that captures the compressibility and rarefaction effects of the fractal mobility is used to study the evolution of these particulates in a canonical Rankine vortex to illustrate the wide disparity in the trajectories of the fractal aggregate vs a spherical geometry approximation generally found in the literature.
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Seng, T. H., S. Suratman, M. R. Abas, and N. M. Tahir. "Emission of Polycyclic Aromatic Hydrocarbons in Smoke Particulates at Three Different Combustion Stages from Burning of Rhizophora apiculate, Melaleuca leucadendron and Hevea brasiliensis Wood." Asian Journal of Chemistry 33, no. 4 (March 20, 2021): 892–96. http://dx.doi.org/10.14233/ajchem.2021.23125.
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The purpose of this study was to characterize and determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) emitted in smoke particulates from burning of Rhizophora apiculata, Melaleuca leucadendron and Hevea Brasilensis at the smouldering, flaming and charring stages. Smoke particulates were sampled using a total suspended particulate Hi-volume sampler (HVS) at a rate of 1.13 m3/min and PAHs were extracted with a mixture of dichloromethane-methanol (3:1 v/v) using ultrasonic agitation. Fractionation of PAHs was carried out on an alumina-silica column and analysis by gas chromatography-mass spectrometry (GC-MS). The results showed that most of the samples exhibited the highest total identified PAHs in the smouldering stage with formation of PAHs with three rings or more increasing from the smouldering to flaming stages and reducing as combustion entered the charring stage. Naphthalene, phenanthrene and pyrene were the dominant PAHs detected in the wood smoke particulates, depending on combustion stage. Overall the emission and formation of PAHs are strongly dependent on combustion stage as well as other factors such as wood morphology, species, moisture content and combustion temperature.
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Sakai, Mitsuaki, Yukio Sato, Shoko Sato, Satoshi Ihara, Masataka Onizuka, Yuzuru Sakakibara, and Hideto Takahashi. "Effect of relocating to areas of reduced atmospheric particulate matter levels on the human circulating leukocyte count." Journal of Applied Physiology 97, no. 5 (November 2004): 1774–80. http://dx.doi.org/10.1152/japplphysiol.00024.2004.
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A high level of atmospheric particulate matter induces an increase in circulating polymorphonuclear leukocyte (PMN) counts and an increase in serum inflammatory cytokine levels. The particulate level in Antarctica is extremely low compared with that in industrial countries. We hypothesized that this low level would reduce circulating leukocyte counts and serum inflammatory cytokine levels in people visiting Antarctica from industrial countries. The number density of particulates with aerodynamic diameters of <10.0 μm was measured in Japan and in Antarctica during the 41st Japanese Antarctic Research Expedition. Circulating leukocyte counts, granulocyte colony-stimulating factor and interleukin-6 levels, and pulmonary function were determined at regular intervals in 39 expedition members. The particulate number density was <1% of that measured in Japan. Total leukocytes, segmented and band-formed PMN, monocyte counts, and serum interleukin-6 levels decreased in Antarctica compared with the initial values measured in Japan. Pulmonary function parameters did not change except for maximal voluntary ventilation. Particulate matter levels had more significant effects on segmented PMN, band-formed PMN, and monocyte counts than cigarette smoking and the type of work. Exposure to reduced atmospheric particulates is considered to be a major factor for decreasing circulating leukocyte counts and serum cytokine levels.
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Orlowski, Gregory, Hiroshi Kataoka, and Kenneth Rock. "Validating cathepsins as selective therapeutic targets for the treatment of particulate-mediated sterile inflammatory disease. (P1373)." Journal of Immunology 190, no. 1_Supplement (May 1, 2013): 63.41. http://dx.doi.org/10.4049/jimmunol.190.supp.63.41.
Full textAbstract:
Abstract IL-1β mediates a multitude of debilitating, and sometimes fatal, acute and chronic inflammatory diseases. However, existing therapies for these diseases target IL-1β directly, suppressing both its pathologic and protective activities. We propose that cathepsins are therapeutic targets specific to IL-1β-mediated inflammatory diseases caused by sterile particulates. These particulates, such as cholesterol crystals (atherosclerosis), silica (silicosis) and monosodium urate (gout), activate the NLRP3 inflammasome in immune cells, leading to active IL-1β secretion. Rather than conferring protection, this response causes disease. Here, we show that a bioavailable inhibitor of cathepsins B, L & C, called K777, specifically suppresses particulate-mediated IL-1β production by primary macrophages. Using primary and immortalized macrophages deficient in cathepsins B & L, we demonstrate these proteases are critical targets likely responsible for much of K777’s effect. Moreover, we show for the first time that, unlike other NLRP3 stimuli, particulate-mediated inflammatory cell death is inflammasome-independent and cathepsin-dependent. Finally, in a murine model of acute peritonitis, both subcutaneous and intravenous K777 treatment substantially and preferentially reduced IL-1β-dependent neutrophil influx caused by particulate stimuli. Together, these data are the first to translate cathepsin inhibition in vitro into an in vivo model, validating cathepsins as potentially selective therapeutic targets in particulate-mediated inflammatory disease.
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Zhu, Bingheng, Qi Xu, and Pengxiang Li. "Investigation of the Flow and Heat Transfer Characteristics and Erosion Law of Particulate in LBE on the Subchannel." Science and Technology of Nuclear Installations 2022 (March 22, 2022): 1–8. http://dx.doi.org/10.1155/2022/2354978.
Full textAbstract:
A triangle subchannel model was established to study the flow and heat transfer characteristics of lead-bismuth eutectic (LBE) alloy and the erosion rate of the core channel by the particulate in LBE. Under different inlet velocities, particle types, particle diameters, and particle concentrations, the erosion law of the channel wall in LEB was investigated by using a discrete phase model (DPM). The results of this study showed that with the increase of inlet velocity, the outlet temperature of the LEB decreases and the heat transfer capacity was strengthened. The increase of inlet velocity will lead to the increase of erosion rate on the wall, and the change is exponential. The erosion rate of particulate in the low concentration is small but cannot be ignored; with increasing concentration of particulates, the erosion of the wall by particulates becomes serious. The effect of particulate density on the wall erosion rate can be ignored. The effect of changing the particle size on the erosion rate is more significant when the particle size is small, and at the same time, the erosion rate of the particles on the wall increases with the increase of the particle size.
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Prasannavenkatesh, Ramachandran, Ramachandran Andimuthu, Palanivelu Kandasamy, Geetha Rajadurai, Divya Subash Kumar, Parthasarathy Radhapriya, and Malini Ponnusamy. "Assessment of Population Exposure to Coarse and Fine Particulate Matter in the Urban Areas of Chennai, India." Scientific World Journal 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/643714.
Full textAbstract:
Research outcomes from the epidemiological studies have found that the course (PM10) and the fine particulate matter (PM2.5) are mainly responsible for various respiratory health effects for humans. The population-weighted exposure assessment is used as a vital decision-making tool to analyze the vulnerable areas where the population is exposed to critical concentrations of pollutants. Systemic sampling was carried out at strategic locations of Chennai to estimate the various concentration levels of particulate pollution during November 2013–January 2014. The concentration of the pollutants was classified based on the World Health Organization interim target (IT) guidelines. Using geospatial information systems the pollution and the high-resolution population data were interpolated to study the extent of the pollutants at the urban scale. The results show that approximately 28% of the population resides in vulnerable locations where the coarse particulate matter exceeds the prescribed standards. Alarmingly, the results of the analysis of fine particulates show that about 94% of the inhabitants live in critical areas where the concentration of the fine particulates exceeds the IT guidelines. Results based on human exposure analysis show the vulnerability is more towards the zones which are surrounded by prominent sources of pollution.