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M R Kholghy, G A Kelesidis, S E Pratsinis
Nucleation is an important, yet poorly understood step in soot formation. Here, the importance of reactive PAH dimerization in reducing soot nucleation reversibility is investigated by simulating soot formation in a so-called "nucleation" flame (P. Desgroux et al., Combust. Flame, 2017, 184, 153-166). There, inception of soot particles is prolonged at minimal subsequent growth. With only reversible PAH dimerization, the simulated soot concentration is negligible. Accounting however for PAH chemical bond formation after physical dimerization, stabilizes dimers by covalent bonds and increases the soot concentration by four orders of magnitude, in good agreement with Laser Induced Incandescence measurements...
March 15, 2018: Physical Chemistry Chemical Physics: PCCP
Rakesh Kumar Maurya, Mohit Raj Saxena, Piyush Rai, Aashish Bhardwaj
Currently, diesel engines are more preferred over gasoline engines due to their higher torque output and fuel economy. However, diesel engines confront major challenge of meeting the future stringent emission norms (especially soot particle emissions) while maintaining the same fuel economy. In this study, nanosize range soot particle emission characteristics of a stationary (non-road) diesel engine have been experimentally investigated. Experiments are conducted at a constant speed of 1500 rpm for three compression ratios and nozzle opening pressures at different engine loads...
March 12, 2018: Environmental Science and Pollution Research International
Milica Ljaljević Grbić, Nikola Unković, Ivica Dimkić, Peđa Janaćković, Milan Gavrilović, Olja Stanojević, Miloš Stupar, Ljubodrag Vujisić, Aleksa Jelikić, Slaviša Stanković, Jelena Vukojević
ETHNOPHARMACOLOGICAL RELEVANCE: Essential oils obtained from resins of Boswellia carteri Birdw. and Commiphora myrrha (Nees) Engl., commonly known as frankincense and true myrrh respectively, have been used extensively since 2800 B.C. for the treatment of skin sores, wounds, teeth, inflammation, and urinary tract diseases in traditional medicine; for preparation of mummification balms and unguents; and also as incense and perfumes. Since ancient times, burning of frankincense and myrrh in places of worship for spiritual purposes and contemplation (a ubiquitous practice across various religions) had hygienic functions, to refine the smell and reduce contagion by purifying the indoor air...
March 9, 2018: Journal of Ethnopharmacology
Florian Hirsch, Philipp Constantinidis, Ingo Fischer, Sjors Bakels, Anouk Rijs
We investigate the self-reaction of benzyl, C7H7 in a high tempera-ture pyrolysis reactor. The work is motivated by the observation that resonance-stabilized benzyl radicals can accumulate in reactive environments and contribute to the formation of polycyclic aromatic hydrocarbons (PAH) and soot. Reaction products are detected by IR/UV ion dip spectroscopy, using infrared radiation from the free electron laser FELIX, and are identified by comparison with com-puted spectra. Among the reaction products identified by their IR absorption are several PAH linked to toluene combustion such as bibenzyl, phenanthrene, diphenylmethane and fluorene...
March 12, 2018: Chemistry: a European Journal
Paul J Hadwin, Timothy A Sipkens, Kevin A Thomson, Fengshan Liu, Kyle J Daun
Time-resolved laser-induced incandescence (TiRe-LII) data can be used to infer spatially and temporally resolved volume fractions and primary particle size distributions of soot-laden aerosols, but these estimates are corrupted by measurement noise as well as uncertainties in the spectroscopic and heat transfer submodels used to interpret the data. Estimates of the temperature, concentration, and size distribution of soot primary particles within a sample aerosol are typically made by nonlinear regression of modeled spectral incandescence decay, or effective temperature decay, to experimental data...
March 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Tao Yu, Hecong Liu, Jiaqi Zhang, Weiwei Cai, Fei Qi
Volumetric tomography for combustion diagnostics is experiencing significant progress during the past few years due to its capability of imaging evolving turbulent flows. Such capability facilitates the understanding of the mechanisms behind complicated combustion phenomena such as lean blowout, acoustic oscillations, and formation of soot particles. However, these techniques are not flawless and suffer from high computational cost which prevents them from applications where real-time reconstructions and online monitoring are necessary...
March 1, 2018: Optics Letters
Nathan J Kempema, Marshall B Long
This Letter reports on the effect of self-absorption on measured temperature for color-ratio soot pyrometry with a color camera. A series of increasingly nitrogen diluted atmospheric pressure ethylene/air laminar coflow diffusion flames are studied, providing flames with different optical path lengths, soot loading, and soot optical properties. Numerical calculations are used to simulate the change in collected flame emission signal with and without light attenuation using experimentally measured maps of the soot absorption coefficient...
March 1, 2018: Optics Letters
Xiaowei Cong
Outdoor air pollution may be associated with cancer risk at different sites. This study sought to investigate outdoor air pollution from waste gas emission effects on multiple cancer incidences in a retrospective population-based study in Shanghai, China. Trends in cancer incidence for males and females and trends in waste gas emissions for the total waste gas, industrial waste gas, other waste gas, SO2 , and soot were investigated between 1983 and 2010 in Shanghai, China. Regression models after adjusting for confounding variables were constructed to estimate associations between waste gas emissions and multiple cancer incidences in the whole group and stratified by sex, Engel coefficient, life expectancy, and number of doctors per 10,000 populations to further explore whether changes of waste gas emissions were associated with multiple cancer incidences...
February 27, 2018: Environmental Science and Pollution Research International
Zhaojun Wen, Xinping Duan, Menglin Hu, Yanning Cao, Linmin Ye, Lilong Jiang, Youzhu Yuan
In this study, the effects of copper (Cu) additive on the catalytic performance of Ag/SBA-15 in complete soot combustion were investigated. The soot combustion performance of bimetallic Ag-Cu/SBA-15 catalysts was higher than that of monometallic Ag and Cu catalysts. The optimum catalytic performance was acquired with the 5Ag1 -Cu0.1 /SBA-15 catalyst, on which the soot combustion starts at Tig =225°C with a T50 =285°C. The temperature for 50% of soot combustion was lower than that of conventional Ag-based catalysts to more than 50°C (Aneggi et al...
February 2018: Journal of Environmental Sciences (China)
Patrick Louchouarn, Shaya M Seward, Gerard Cornelissen, Hans Peter H Arp, Kevin M Yeager, Robin Brinkmeyer, Peter H Santschi
Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal. Station SG-6, sampled at the site of the submerged waste pit, had the highest dioxin/furan concentrations reported for the Houston Ship Channel/Galveston Bay (HSC/GB) system (10,000-46,000 pg/g), which translated into some of the highest reported World Health Organization Toxic Equivalents (TEQs: 2000-11,000 pg/g) in HSC sediments...
February 20, 2018: Environmental Pollution
David R Johnson, Robert E Boyd, Anthony J Bednar, Charles A Weiss, Matt S Hull, Jessica G Coleman, Alan J Kennedy, Cynthia J Banks, Jeffery A Steevens
The synthesis of carbon-based nanomaterials is often inefficient, generating large amounts of soot with metals as waste by-product. Currently, there are no specific regulations for disposal of engineered nanomaterials or the waste by-products resulting from their synthesis, so it is presumed that by-products are disposed of the same as the parent (bulk) materials. Here we study the terrestrial toxicity of soot from gadolinium metallofullerene nanomanufacturing on earthworms (Eisenia fetida) and isopods (Porcellio scaber)...
February 23, 2018: Environmental Toxicology and Chemistry
K Donaldson, W A Wallace, T A Elliot, C Henry
By the mid-19th century about 200,000 miners were employed in a UK coal mining industry still growing with the advances of the Industrial Revolution. Coal miners were long known to suffer poor health but the link to inhaling dust in the mines had not been made. In 1813 George Pearson was the first to suggest that darkening of lungs seen in normal individuals as they aged was caused by inhaled soot from burning oil, candles and coal, which were the common domestic sources of heat and light. In 1831 Dr James Craufurd Gregory first described black pigmentation and disease in the lungs of a deceased coal miner and linked this to pulmonary accumulation of coal mine dust...
September 2017: Journal of the Royal College of Physicians of Edinburgh
Tafeng Hu, Junji Cao, Chongshu Zhu, Zhuzi Zhao, Suixin Liu, Daizhou Zhang
Many studies indicate that the atmospheric environment over the southern part of the Tibetan Plateau is influenced by aged biomass burning particles that are transported over long distances from South Asia. However, our knowledge of the particles emitted locally (within the plateau region) is poor. We collected aerosol particles at four urban sites and one remote glacier site during a scientific expedition to the southeastern Tibetan Plateau in spring 2010. Weather and backward trajectory analyses indicated that the particles we collected were more likely dominated by particles emitted within the plateau...
February 14, 2018: Science of the Total Environment
Seuk-Cheun Choi, Seul-Hyun Park
In the present study, the soot particles produced from diffusion flames burning biodiesel fuel were thermophoretically sampled and the carbon nanostructure of soot particles were imaged using a high resolution transmission electron microscopy (HRTEM). The HRTEM images of soot particles were then quantitatively analyzed using a digital image processing algorithm developed and implemented as part of this work. The HRTEM interpretations with an aid of image processing support feasibility of use of the developed image processing technique for carbon nanostructure quantification...
March 1, 2018: Journal of Nanoscience and Nanotechnology
Won-Ju Lee, Seul-Hyun Park, Se-Hyun Jang, Hwajin Kim, Sung Kuk Choi, Kwon-Hae Cho, Ik-Soon Cho, Sang-Min Lee, Jae-Hyuk Choi
Diesel soot particles were sampled from 2-stroke and 4-stroke engines that burned two different fuels (Bunker A and C, respectively), and the effects of the engine and fuel types on the structural characteristics of the soot particle were analyzed. The carbon nanostructures of the sampled particles were characterized using various techniques. The results showed that the soot sample collected from the 4-stroke engine, which burned Bunker C, has a higher degree of order of the carbon nanostructure than the sample collected from the 2-stroke engine, which burned Bunker A...
March 1, 2018: Journal of Nanoscience and Nanotechnology
Pravin Jagdale, Samera Salimpour, Md Hujjatul Islam, Fabio Cuttica, Francisco C Robles Hernandez, Alberto Tagliaferro, Alberto Frache
Polydimethylsiloxane has exceptional fire retardancy characteristics, which make it a popular polymer in flame retardancy applications. Flame retardancy of polydimethylsiloxane with different nano fillers was studied. Polydimethylsiloxane composite fire property varies because of the shape, size, density, and chemical nature of nano fillers. In house made carbon and bismuth oxide nano fillers were used in polydimethylsiloxane composite. Carbon from biochar (carbonised bamboo) and a carbon by-product (carbon soot) were selected...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Xiaohui Chen, Ruting Xu, Yanting Xu, Hui Hu, Shouquan Pan, Hongkun Pan
Sawdust was expected to remove impurities in waste lubricant, and was modified with sodium hydroxide and triethanolamine, which can ameliorate its surface properties and improve its adsorption capacity. The increase of hydroxyl groups, the decrease of carbonyl groups and grafting new azyl after modification were beneficial for the adsorption of impurities. The surface area of modified sawdust is 0.969 m 2 g -1 , which is nearly 1.39 times as much as raw sawdust. The point of zero charge for modified sawdust decreased from 6...
February 1, 2018: Journal of Hazardous Materials
Veronika Pilz, Kathrin Wolf, Susanne Breitner, Regina Rückerl, Wolfgang Koenig, Wolfgang Rathmann, Josef Cyrys, Annette Peters, Alexandra Schneider
BACKGROUND: Long-term exposure to ambient air pollution contributes to the global burden of disease by particularly affecting cardiovascular (CV) causes of death. We investigated the association between particle number concentration (PNC), a marker for ultrafine particles, and other air pollutants and high sensitivity C-reactive protein (hs-CRP) as a potential link between air pollution and CV disease. METHODS: We cross-sectionally analysed data from the second follow up (2013 and 2014) of the German KORA baseline survey which was conducted in 1999-2001...
January 31, 2018: International Journal of Hygiene and Environmental Health
M S Swapna, S Sankararaman
The present work describes a solution for the effective use of the hazardous particulate matter (diesel soot) from the internal combustion engines (ICEs) as a potential material emitting white light for white light emitting diodes (WLEDs). The washed soot samples are subjected to Field Emission Scanning Electron Microscopy (FESEM), High- Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive Spectroscopy (EDS), UV-Visible, Photoluminescent (PL) Spectroscopy and quantum yield measurements. The CIE plot and Correlated Color Temperature (CCT) reveals the white fluorescence on photoexcitation...
February 5, 2018: Journal of Fluorescence
Hong-Wei Zang, He-Long Li, Yue Su, Yao Fu, Meng-Yao Hou, Andrius Baltuška, Kaoru Yamanouchi, Huailiang Xu
Coherent radiation in the ultraviolent (UV) range has high potential applicability to the diagnosis of the formation processes of soot in combustion because of the high scattering efficiency in the UV wavelength region, even though the UV light is lost largely by the absorption within the combustion flames. We show that the third harmonic (TH) of a Ti:sapphire 800 nm femtosecond laser is generated in a laser-induced filament in a combustion flame and that the conversion efficiency of the TH varies sensitively by the ellipticity of the driver laser pulse but does not vary so much by the choice of alkanol species introduced as fuel for the combustion flames...
February 1, 2018: Optics Letters
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