Search results for " burning"
showing 10 items of 29 documents
Nature of the non-exponential primary relaxation in structural glass-formers probed by dynamically selective experiments
1998
Several experimental methods feature the potential to distinguish between slow and fast contributions to the non-exponential, ensemble averaged primary response in glass-forming materials. Some of these techniques are based on the selection of subensembles using multi-dimensional nuclear magnetic resonance, optical bleaching, and non-resonant spectral hole burning. Others, such as the time-dependent solvation spectroscopy, measure microscopic responses induced by local perturbations. Using several of these methods it could be demonstrated for various glass-forming materials that the non-exponential relaxation results from a superposition of dynamically distinguishable entities. The experime…
The Impact of Candle Burning During All Saints’ Day Ceremonies on Ambient Alkyl-Substituted Benzene Concentrations
2013
Research findings concerning benzene, toluene, ethylobenzene, meta-, para- and ortho-xylene as well as styrene (BTEXS) emission at public cemeteries during All Saints’ Day are presented here. Tests were carried out at town-located cemeteries in Opole and Grodków (southern Poland) and, as a benchmark, at the centres of those same towns. The purpose of the study was to estimate BTEXS emissions caused by the candle burning and, equally important to examine, whether emissions generated by the tested sources were similar to the BTEXS emissions generated by road transport. During the festive period, significant increases in benzene concentrations, by 200 % and 144 %, were noted at the cemeteries …
Probing the low-temperature chemistry of ethanol via the addition of dimethyl ether
2018
Considering the importance of ethanol (EtOH) as an engine fuel and a key component of surrogate fuels, the further understanding of its auto-ignition and oxidation characteristics at engine-relevant conditions (high pressures and low temperatures) is still necessary. However, it remains difficult to measure ignition delay times for ethanol at temperatures below 850 K with currently available facilities including shock tube and rapid compression machine due to its low reactivity. Considering the success of our recent study of toluene oxidation under similar conditions [38], dimethyl ether (DME) has been selected as a radical initiator to explore the low-temperature reactivity of ethanol. In …
The association between burning mouth syndrome and sleep disturbance: A case-control multicentre study
2018
Objectives: To investigate the quality of sleep and the psychological profiles of a large cohort of Italian patients with burning mouth syndrome (BMS) and to clarify the relationships between these variables and pain. Methods: In this case–control study, 200 patients with BMS vs an equal number of age- and sex-matched healthy controls, recruited in 10 universities, were enrolled. The Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Hamilton Rating Scale for Depression (HAM-D), Hamilton Rating Scale for Anxiety (HAM-A), Numeric Pain Intensity Scale (NRS) and Total Pain Rating Index (T-PRI) were administered. Descriptive statistics, including the Mann–Whitney U test and …
Burning mouth syndrome: is acupuncture a therapeutic possibility?
2010
Burning mouth syndrome is a chronic pathology of unknown ethiopathogenesis. The aim of this study was to evaluate whether acupuncture can produce a reduction of the burning sensation by influencing the oral microcirculation. METHODS: Thirty patients (10 male and 20 female; mean age +/- SD = 65.4 +/- 2.17) and 30 healthy subjects (10 male and 20 female; mean age +/- SD = 62.06 +/- 6.72) were recruited for the study. The patients were treated with acupunctural techniques based on traditional Chinese medicine. Microcirculation was observed in vivo using videocapillaroscopy at three different times: t(0)) in the absence of acupuncture; t(1)) 1 minute after the insertion of the needles; and t(2)…
Salivary and serum levels of substance p, neurokinin A and calcitonin gene related peptide in burning mouth syndrome
2009
Background: Burning mouth syndrome (BMS) is an enigmatic condition with the etiopathogenesis remaining largely obscure. However, a neuropathic basis for BMS continues to be an area of active clinical and research interest. Aim: It is becoming increasingly evident that certain oral disorders may be modulated by imbalances in certain neuropeptides such as substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) therefore we measured SP, NKA and CGRP in the saliva and sera of BMS patients as well as controls. Subjects and Methods: Salivary and serum SP, NKA and CGRP were determined in the 26 female patients with burning mouth syndrome (age range 51-78, mean 65.69 yrs), a…
Slow Dielectric Relaxation of Supercooled Liqutos Investigated by Nonresonant Spectral Hole Burning
1996
ABSTRACTWhen supercooled propylene carbonate and glycerol are subjected to a large-amplitude, low-frequency electric field, a spectral hole develops in their dielectric relaxation that is significantly narrower than their bulk response. This observation of nonresonant spectral hole burning establishes that the non-Debye response is due to a distribution of relaxation times. Refilling of the spectral hole occurs abruptly, indicative of a single recovery rate that corresponds to the peak in the distribution. The general shape of the spectral hole is preserved during recovery, indicating negligible interaction between the degrees of freedom that responded to the field. All relevant features in…
Nonresonant Spectral Hole Burning in the Slow Dielectric Response of Supercooled Liquids
1996
Large-amplitude, low-frequency electric fields can be used to burn spectral holes in the dielectric response of supercooled propylene carbonate and glycerol. This ability to selectively modify the dielectric response establishes that the non-Debye behavior results from a distribution of relaxation times. Refilling of the spectral hole was consistent with a single recovery time that coincided with the peak in the distribution. Moreover, refilling occurred without significant broadening, which indicates negligible direct exchange between the degrees of freedom that responded to the field. Nonresonant spectral hole burning facilitates direct investigation of the intrinsic response of systems t…
Response-theory for nonresonant hole burning: Stochastic dynamics
2001
Using non-linear response theory the time signals relevant for nonresonant spectral hole burning are calculated. The step-reponse function following the application of a high amplitude ac field (pump) and an intermediate waiting period is shown to be the sum of the equilibrium integrated response and a modification due to the preparation via ac irradiation. Both components are calculated for a class of stochastic dipole reorientation models. The results indicate that the method can be used for a clearcut distinction of homogeneously and heterogeneously broadened susceptibilities as they occur in the relaxation of supercooled liquids or other disordered materials. This is because only in the…
First measurements of reactive α-dicarbonyl concentrations on PM2.5 aerosol over the Boreal forest in Finland during HUMPPA-COPEC 2010 – source…
2012
The first dataset for summertime boreal forest concentrations of two atmospherically relevant α-dicarbonyl compounds, glyoxal (Gly) and methylglyoxal (Mgly) on PM2.5 aerosol was obtained during the HUMPPA-COPEC-2010 field measurement intensive in Hyytiälä, Finland. Anthropogenic influences over the course of the campaign were identified using trace gas signatures and aerosol particle chemical composition analysis. The data evaluation allowed the identification of different events such as urban pollution plumes, biomass burning and sawmill emissions as sources of high Gly and Mgly concentrations. Mean aerosol concentrations during periods of biogenic influence were 0.81 ng m−3 for Gly and 0.…