Search results for "burning"
showing 10 items of 94 documents
Nonresonant dielectric hole burning spectroscopy of supercooled liquids
1997
The nonexponential response of propylene carbonate and glycerol near their glass transitions could be selectively altered using nonresonant spectral hole burning (NSHB) experiments. This observation provides evidence of the existence of a distribution of relaxation times in these supercooled liquids. NSHB is based on a pump, wait, and probe scheme and uses low-frequency large amplitude electrical fields to modify the dielectric relaxation. The temporal evolution of the polarization of the sample is then measured subsequent to a small voltage step. By variation of a recovery time inserted between pump and probe, the refilling of the spectral features could be monitored and was found to take …
Brown Carbon Aerosol in Urban Xi'an, Northwest China: The Composition and Light Absorption Properties.
2018
Light-absorbing organic carbon (i.e., brown carbon or BrC) in the atmospheric aerosol has significant contribution to light absorption and radiative forcing. However, the link between BrC optical properties and chemical composition remains poorly constrained. In this study, we combine spectrophotometric measurements and chemical analyses of BrC samples collected from July 2008 to June 2009 in urban Xi'an, Northwest China. Elevated BrC was observed in winter (5 times higher than in summer), largely due to increased emissions from wintertime domestic biomass burning. The light absorption coefficient of methanol-soluble BrC at 365 nm (on average approximately twice that of water-soluble BrC) w…
Biogenic and biomass burning organic aerosol in a boreal forest at Hyytiälä, Finland, during HUMPPA-COPEC 2010
2013
Abstract. Submicron aerosol particles were collected during July and August 2010 in Hyytiälä, Finland, to determine the composition and sources of aerosol at that boreal forest site. Submicron particles were collected on Teflon filters and analyzed by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFGs). Positive matrix factorization (PMF) was applied to aerosol mass spectrometry (AMS) measurements and FTIR spectra to identify summertime sources of submicron aerosol mass at the sampling site. The two largest sources of organic mass (OM) in particles identified at Hyytiälä were (1) biogenic aerosol from surrounding local forest and (2) biomass burning aerosol, …
The AeroCom evaluation and intercomparison of organic aerosol in global models
2014
This paper evaluates the current status of global modeling of the organic aerosol (OA) in the troposphere and analyzes the differences between models as well as between models and observations. Thirty-one global chemistry transport models (CTMs) and general circulation models (GCMs) have participated in this intercomparison, in the framework of AeroCom phase II. The simulation of OA varies greatly between models in terms of the magnitude of primary emissions, secondary OA (SOA) formation, the number of OA species used (2 to 62), the complexity of OA parameterizations (gas-particle partitioning, chemical aging, multiphase chemistry, aerosol microphysics), and the OA physical, chemical and op…
Influx of African biomass burning aerosol during the Amazonian dry season through layered transatlantic transport of black carbon-rich smoke
2020
Black carbon (BC) aerosols influence the Earth's atmosphere and climate, but their microphysical properties, spatiotemporal distribution, and long-range transport are not well constrained. This study presents airborne observations of the transatlantic transport of BC-rich African biomass burning (BB) smoke into the Amazon Basin using a Single Particle Soot Photometer (SP2) as well as several complementary techniques. We base our results on observations of aerosols and trace gases off the Brazilian coast onboard the HALO (High Altitude and LOng range) research aircraft during the ACRIDICON-CHUVA campaign in September 2014. During flight AC19 over land and ocean at the northeastern coastline …
Application of aerosol optical properties to estimate aerosol type from ground-based remote sensing observation at urban area of northeastern China
2015
Abstract Aerosol optical properties were derived from ground-based sunphotometer observations between 2009-2013 at three urban sites of Shenyang, Anshan, Fushun in northeastern China. The annual means for extinction aerosol optical depths (EAOD) at 500 nm were 0.57±0.38, 0.52±0.35, and 0.41±0.31 at Shenyang, Anshan, Fushun, respectively. The corresponding annual means for the extinction Angstrom exponents (EAE) computed for the wavelengths of 440 and 870 nm were 0.86±0.32, 0.86±0.34 and 0.91±0.35, respectively, indicating that urban area of Northeast China were affected by both coarse and fine particles. Hygroscopic growth in summer and incursions of dust aerosols in spring were evidently r…
Topical capsaicin application and axon reflex vasodilatation of the tongue: Neurogenic involvement in burning mouth syndrome.
2006
The aim of this study was to evaluate the effects of topical capsaicin application on human lingual mucosa and to assess if neurogenic inflammation might have a role in the pathogenesis of lingual diseases. Thirty patients (16 males and 14 females; mean age: 41.46 +/- 11.8 years; range: 23-60) were examined in our laboratory. The neurogenic inflammation was experimentally induced in the lingual mucosa close to 1) the left margin of the tongue and 2) the right margin of the tongue after ipsilateral nerve trunk anesthesia. The characteristics of lingual microcirculation were observed using computerized videocapillaroscopic techniques. The vasodilatation was observed close to the left margin o…
LA SINDROME DELLA BOCCA CHE BRUCIA
2007
Burning mouth syndrome (BMS) is characterized by burning sensations of the oral cavity in the absence of abnormalities of the oral mucosa. BMS predominantly affects middle-aged women. This condition has a multifactorial etiology. Multiple approaches to treatment have been described. This article examines BMS, its related factors, and treatment options.
Oral manifestations in patients with gastro-oesophageal reflux disease: a single-center case-control study
2008
OBJECTIVE: To assess the occurrence of oral pathological changes and symptoms in patients affected by gastro-oesophageal reflux disease (GERD). PATIENTS AND METHODS: 200 patients with GERD and 100 matched healthy controls were studied. Thorough visual examination of the dental and oral mucosal tissues was performed and medical history relevant to oral symptoms was collected. The primary outcome was defined as a statistically significant difference, between the study group and controls, in the presence of the following indicators: soft/hard palate and uvula erythema, tooth wear, xerostomia, oral acid/burning sensation, subjective halitosis and dental sensitivity. Statistical analysis include…
Excitonic energy level structure and pigment-protein interactions in the recombinant water-soluble chlorophyll protein. II. Spectral hole-burning exp…
2011
Persistent spectral hole burning at 4.5 K has been used to investigate the excitonic energy level structure and the excited state dynamics of the recombinant class-IIa water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The hole-burned spectra are composed of four main features: (i) a narrow zero-phonon hole (ZPH) at the burn wavelength, (ii) a number of vibrational ZPHs, (iii) a broad low-energy hole at ~665 and ~683 nm for chlorophyll b- and chlorophyll a-WSCP, respectively, and (iv) a second satellite hole at ~658 and ~673 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. The doublet of broad satellite holes is assigned to an excitonically coupled chlorophyll dim…