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Dingyu Hou, Xiaoqing You
Hydrogen abstraction reactions of polycyclic aromatic hydrocarbons (PAH) by H atoms play a very important role in both PAH and soot formation processes. However, large discrepancies up to a few orders of magnitude exist among the literature rate constant values. To increase the reliability of the computed rate constants, it is critical to obtain highly accurate potential energy surfaces. For this purpose, we have investigated the energetics of hydrogen abstraction from benzene and naphthalene using both high level-of-theory quantum chemistry methods and a series of density functional theory (DFT) methods, among which M06-2X/6-311g(d,p) has the best performance with a mean unsigned deviation from the CCSD(T)/CBS calculations of 1...
November 14, 2017: Physical Chemistry Chemical Physics: PCCP
Jialei Zhu, Joyce E Penner, Guangxing Lin, Cheng Zhou, Li Xu, Bingliang Zhuang
Secondary organic aerosol (SOA) nearly always exists as an internal mixture, and the distribution of this mixture depends on the formation mechanism of SOA. A model is developed to examine the influence of using an internal mixing state based on the mechanism of formation and to estimate the radiative forcing of SOA in the future. For the present day, 66% of SOA is internally mixed with sulfate, while 34% is internally mixed with primary soot. Compared with using an external mixture, the direct effect of SOA is decreased due to the decrease in total aerosol surface area and the increase of absorption efficiency...
November 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
Junfeng Wang, Qi Zhang, Min-Dong Chen, Sonya Collier, Shan Zhou, Xinlei Ge, Jianzhong Xu, Jinsen Shi, Conghui Xie, Jianlin Hu, Shun Ge, Yele Sun, Hugh Coe
Refractory black carbon (rBC) aerosol is an important climate forcer, and its impacts are greatly influenced by the species associated with rBC cores. However, relevant knowledge is particularly lacking at the Tibetan Plateau (TP). Here we report, for the first time, highly time-resolved measurement results of rBC and its coating species in central TP (4730 m a.s.l), by using an Aerodyne soot particle aerosol mass spectrometer (SP-AMS), which selectively measured rBC-containing particles. We found that the rBC was overall thickly coated with an average mass ratio of coating to rBC (RBC) of ~7...
November 13, 2017: Environmental Science & Technology
Christoph G Birngruber, Florian Veit, Juliane Lang, Marcel A Verhoff
The corpse of a 71-year-old woman was found on the floor of her smoke-filled room. The source of the fire was the mattress of a double bed on which newspapers had apparently been set aflame. The woman's history in conjunction with the finding situation suggested an act of suicide. No signs of soot inhalation or soot swallowing were found at autopsy. Other vital signs were absent. Severe cardiac disease was the most notable pre-existing medical condition. Although the concentration of COHb in heart blood was low (3%), the concentration of cyanide was found to be 4...
November 6, 2017: Forensic Science International
Thomas Christiansen, Marine Cotte, René Loredo-Portales, Poul Erik Lindelof, Kell Mortensen, Kim Ryholt, Sine Larsen
For the first time it is shown that carbon black inks on ancient Egyptian papyri from different time periods and geographical regions contain copper. The inks have been investigated using synchrotron-based micro X-ray fluorescence (XRF) and micro X-ray absorption near-edge structure spectroscopy (XANES) at the European Synchrotron Radiation Facility (ESRF). The composition of the copper-containing carbon inks showed no significant differences that could be related to time periods or the geographical locations...
November 10, 2017: Scientific Reports
Gianluigi De Falco, Chiara Colarusso, Michela Terlizzi, Ada Popolo, Michela Pecoraro, Mario Commodo, Patrizia Minutolo, Mariano Sirignano, Andrea D'Anna, Rita P Aquino, Aldo Pinto, Antonio Molino, Rosalinda Sorrentino
Chronic obstructive pulmonary disease (COPD) is considered the fourth-leading causes of death worldwide; COPD is caused by inhalation of noxious indoor and outdoor particles, especially cigarette smoke that represents the first risk factor for this respiratory disorder. To mimic the effects of particulate matter on COPD, we isolated peripheral blood mononuclear cells (PBMCs) and treated them with combustion-generated ultrafine particles (UFPs) obtained from two different fuel mixtures, namely, pure ethylene and a mixture of ethylene and dimethylfuran (the latter mimicking the combustion of biofuels)...
2017: Frontiers in Immunology
Kunio Kaiho, Naga Oshima
Sixty-six million years ago, an asteroid approximately 9 km in diameter hit the hydrocarbon- and sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot and sulfate aerosols and causing extreme global cooling and drought. These events triggered a mass extinction, including dinosaurs, and led to the subsequent macroevolution of mammals. The amount of hydrocarbon and sulfur in rocks varies widely, depending on location, which suggests that cooling and extinction levels were dependent on impact site...
November 9, 2017: Scientific Reports
Daniel Freno, James Sahawneh, Sarah Harrison, Tim Sahawneh, Scott Patterson, Steven A Kahn
BACKGROUND: Upper airway injuries can be fatal in burn patients if not recognized, a scenario that causes a significant amount of anxiety for physicians providing initial assessment of burn patients. Early elective intubation is often performed; sometimes unnecessarily. However, some providers employ nasolaryngoscopy for patients presenting with facial burns or signs/symptoms of upper airway injury in order to assess the need for intubation, but this practice is not considered standard of care and may also be unnecessary...
November 6, 2017: Burns: Journal of the International Society for Burn Injuries
Giovanni Ferraro, Emiliano Fratini, Riccardo Rausa, Piero Baglioni
HYPOTHESIS: Soot is a black powder-like substance consisting of carbonaceous amorphous particles, formed by incomplete combustion of hydrocarbons. In the last decades, industrial research on lubricant oils has grown to develop more efficient formulations, mainly to reduce the formation of soot in oil so to increase engine lifetime. The comprehension of the mechanism of soot formation and particles growth/aggregation in times during real applications is of fundamental importance for the design of better performing lubricants...
October 10, 2017: Journal of Colloid and Interface Science
Bijay Kumar Poudel, Jae Hong Park, Jiseok Lim, Jeong Hoon Byeon
Labeling of aerosol particles with a radioactive, magnetic, or optical tracer has been employed to confirm particle localization in cell compartments, which has provided useful evidence for correlating toxic effects of inhaled particles. However, labeling requires several physicochemical steps to identify functionalities of the inner or outer surfaces of particles, and moreover, these steps can cause changes in size, surface charge, and bioactivity of the particles, resulting in misinterpretations regarding their toxic effects...
October 23, 2017: Nanotoxicology
Raphael Mansmann, Thomas Dreier, Christof Schulz
Photomultiplier tubes (PMTs) are widely used as detectors for laser-induced incandescence (LII), a diagnostics method for gas-borne particles that requires signal detection over a large dynamic range with nanosecond time resolution around the signal peak. Especially when more than one PMT is used (i.e., for pyrometric temperature measurements) even small deviations from the linear detector response can lead to significant errors. Reasons for non-linearity observed in other PMT measurement techniques are summarized and strategies to identify non-linear PMT operation in LII are outlined...
October 1, 2017: Applied Optics
Fredrik R Westlye, Keith Penney, Anders Ivarsson, Lyle M Pickett, Julien Manin, Scott A Skeen
This work presents the development of an optical setup for quantitative, high-temporal resolution line-of-sight extinction imaging in harsh optical environments. The application specifically targets measurements of automotive fuel sprays at high ambient temperature and pressure conditions where time scales are short and perceived attenuation by refractive index gradients along the optical path (i.e., beam steering) can be significant. The illumination and collection optics are optimized to abate beam steering, and the design criteria are supported by well-established theoretical relationships...
June 10, 2017: Applied Optics
Da Li, Nan Zeng, Dongjian Zhan, Yuerong Chen, Maomao Zeng, Hui Ma
Soot is the main light-absorbing particle in the visible range. Light scattering and absorption by air particulates can change their optical polarization state, and the information upon polarization can reflect the nature of particles. In this paper, a polarization scattering method has been developed for the feasibility study concerning differentiating soot from other typical air particulates. Simulation results indicate that S2/S0 at the scattering angle of 115° can identify the soot particles specifically...
May 10, 2017: Applied Optics
Changlin Zhan, Jiaquan Zhang, Jingru Zheng, Ruizhen Yao, Ping Wang, Hongxia Liu, Wensheng Xiao, Xianli Liu, Junji Cao
Aerosol samples of PM2.5 and PM10 were collected every 6 days from March 2012 to February 2013 in Huangshi, a typical industrial city in central China, to investigate the characteristics, relationships, and sources of carbonaceous species. The PM2.5 and PM10 samples were analyzed for organic carbon (OC), elemental carbon (EC), char, and soot using the thermal/optical reflectance (TOR) method following the IMPROVE_A protocol. PM2.5 and PM10 concentrations ranged from 29.37 to 501.43 μg m(-3) and from 50...
October 18, 2017: Environmental Science and Pollution Research International
Ségolène Vandevelde, Jacques Élie Brochier, Christophe Petit, Ludovic Slimak
Soot marks, witnesses of past human activities, can sometimes be noticed in concretions (speleothem, travertine, carbonated crust, etc.) formed in cavities. We demonstrate here that these deposits, generally ignored in archaeological studies, turned out to be a perfectly suitable material for micro-chronological study of hominin activities in a site. At the Grotte Mandrin (Mediterranean France), thousands of clastic fragments from the rock walls were found in every archaeological level of the shelter. Calcareous crusts containing soot deposits are recorded on some of their surfaces...
November 2017: Journal of Human Evolution
Sushil Kumar Bharti, Dhananjay Kumar, Sangeeta Anand, Poonam, Shymal Chandra Barman, Narendra Kumar
Airborne particulate matters were collected during the period of October 2015 to September 2016 in Lucknow at different sampling sites. The annual mean concentration of particulate matter was found to be relatively higher than the limits prescribed by National ambient air quality standards (NAAQS), United State Environmental Protection Agency (USEPA) and World Health Organization (WHO). Particulate matters were studied for morphological analysis, elemental composition and functional group variability with the help of Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) followed by Fourier Transform Infrared spectroscopy (FTIR)...
September 14, 2017: Micron: the International Research and Review Journal for Microscopy
Ulrich M Hanke, Christopher M Reddy, Ana L L Braun, Alysha I Coppola, Negar Haghipour, Cameron P McIntyre, Lukas Wacker, Li Xu, Ann P McNichol, Samuel Abiven, Michael W I Schmidt, Timothy I Eglinton
Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate (14)C records for two complementary PyC molecular markers, benzene polycarboxylic acids (BPCAs) and polycyclic aromatic hydrocarbons (PAHs), preserved in aquatic sediments from a suburban and a remote catchment in the United States (U...
November 7, 2017: Environmental Science & Technology
Shuqin Jiang, Xingnan Ye, Ruyu Wang, Ye Tao, Zhen Ma, Xin Yang, Jianmin Chen
Measurements of particle size distribution and size-resolved particle volatility were conducted using a volatility tandem differential mobility analyzers (V-TDMA) in the urban area of Shanghai during wintertime in January 2014. The nonvolatile mode particles with VSF exceeding 0.85 were always externally mixed with more-volatile mode particles. The average VSF ranged from 0.58 to 0.65 for 100-400nm particles, increasing with the increase of particle size. On average, the nonvolatile mode contributed 15-20% of number fraction for 50-400nm particles...
February 15, 2018: Science of the Total Environment
A A Gusarov, I Yu Makarov, V A Fetisov
The specific features of soot deposition after a shot fired from the Kalashnikov AK-74 assault rifle are determined by the influence of the multiple factors, with the effect of the muzzle brake (MB) designed to enhance fire density and decrease the fire recoil energy being prevalent over other factors. The special windows, slots and holes in the muzzle brake mechanism are responsible for the appearance of the specific topographic features of soot deposition formed by the combustion gases passing through the assembly...
2017: Sudebno-meditsinskaia Ekspertiza
Yanyan Zhang, Joseph J Pignatello, Shu Tao
Aging soot in soil under neutral aqueous condition for 30days significantly (p<0.05) reduced the apparent gastrointestinal bioaccessibility (Bapp) of polycyclic aromatic hydrocarbons (PAHs) and PAH derivatives (d-PAHs) natively present in a composite fuel soot sample. Bapp was determined under fasting conditions by a previously developed in vitro digestive model that includes silicone sheet as a third phase absorptive sink in the small intestinal stage. Redistribution of contaminants from soot to soil, determined in independent experiments, was too small to affect Bapp...
February 15, 2018: Science of the Total Environment
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