The Influence of Mechanical-Angle on the Quartz Filter Features

Abstract. The sampling artifacts (both positive and negative) and the influence of thermal-optical methods (both charring correction method and the peak inert mode temperature) on the split of organic carbon (OC) and elemental carbon (EC) were evaluated in Beijing. The positive sampling artifact constituted 10% and 23% of OC concentration determined by the bare quartz filter during winter and summer, respectively. For summer samples, the adsorbed gaseous organics were found to continuously evolve off the filter during the whole inert mode when analyzed by the IMPROVE-A temperature protocol. This may be due to the oxidation of the adsorbed organics during sampling (reaction artifact) which would increase their thermal stability. The backup quartz approach was evaluated by a denuder-based method for assessing the positive artifact. The quartz-quartz (QBQ) in series method was demonstrated to be reliable, since all of the OC collected by QBQ was from originally gaseous organics. Negative artifact that could be adsorbed by quartz filter was negligible. When the activated carbon impregnated glass fiber (CIG) filter was used as the denuded backup filter, the denuder efficiency for removing gaseous organics that could be adsorbed by the CIG filter was only about 30%. EC values were found to differ by a factor of about two depending on the charring correction method. Influence of the peak inert mode temperature was evaluated based on the summer samples. The EC value was found to continuously decrease with the peak inert mode temperature. Premature evolution of light absorbing carbon began when the peak inert mode temperature was increased from 580 to 650 °C; when further increased to 800 °C, the OC and EC split frequently occurred in the He mode, and the last OC peak was characterized by the overlapping of two separate peaks. The discrepancy between EC values defined by different temperature protocols was larger for Beijing carbonaceous aerosol compared with North America and Europe, perhaps due to the higher concentration of brown carbon in Beijing aerosol.

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The Influence of Mechanical-stress on the Quartz Filter Features

Physical Science International Journal ◽

10.9734/psij/2018/19858 ◽

2018 ◽

pp. 1-6

Author(s):

Gao Ao ◽

Xia Gang ◽

Kong Yong

Keyword(s):

Mechanical Stress ◽

Transmission Spectrum ◽

Quartz Crystal ◽

Experimental System ◽

Center Wavelength ◽

Quartz Filter ◽

Filter Output ◽

Set Up ◽

The Relationship ◽

Correct Design

In order to study the effect of mechanical-stress on the quartz filter output, based on the elasto-optical effect of quartz crystal, the relationship between berifringent difference of quratz plate and mechanical-stress is deduced, the experimental system is set up by using Ultra-6600 UV spectrophotometer, and received the transmission spectrum of Lyot quartz birefringence filter, the transmission spectrum was investigated theoretically and experimentally in detail. The results show that when applied different mechanical stresses, the center wavelength of quartz birefringent filter changed, and the drifting direction of the center wavelength is related to the size of applied mechanical stress, the drifting size of the center wavelength is related to the direction of applied mechanical stress. It is helpful for the manufacturing, correct design and application of quartz birefringence filter.

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Thermal expansion effect on thickness-shear vibrations in a piezoelectric quartz filter with dot-ring electrodes

International Journal of Heat and Technology ◽

10.18280/ijht.360223 ◽

2018 ◽

Vol 36 (2) ◽

pp. 595-601

Author(s):

Xiangyang Li ◽

Jing Liu

Keyword(s):

Thermal Expansion ◽

Quartz Filter ◽

Piezoelectric Quartz ◽

Thermal Expansion Effect ◽

Expansion Effect ◽

Thickness Shear

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Measurement of carbonaceous aerosol with different sampling configurations and frequencies

Atmospheric Measurement Techniques ◽

10.5194/amt-8-2639-2015 ◽

2015 ◽

Vol 8 (7) ◽

pp. 2639-2648 ◽

Cited By ~ 6

Author(s):

Y. Cheng ◽

K.-B. He

Keyword(s):

Particulate Matter ◽

Chemical Speciation ◽

Fine Particulate Matter ◽

Monitoring Network ◽

Airborne Particulate Matter ◽

Carbonaceous Aerosol ◽

Monitoring Networks ◽

Quartz Filter ◽

Sampling Duration ◽

The Impact

Abstract. A common approach for measuring the mass of organic carbon (OC) and elemental carbon (EC) in airborne particulate matter involves collection on a quartz fiber filter and subsequent thermal–optical analysis. Although having been widely used in aerosol studies and in PM2.5 (fine particulate matter) chemical speciation monitoring networks in particular, this measurement approach is prone to several types of artifacts, such as the positive sampling artifact caused by the adsorption of gaseous organic compounds onto the quartz filter, the negative sampling artifact due to the evaporation of OC from the collected particles and the analytical artifact in the thermal–optical determination of OC and EC (which is strongly associated with the transformation of OC into char OC and typically results in an underestimation of EC). The presence of these artifacts introduces substantial uncertainties to observational data on OC and EC and consequently limits our ability to evaluate OC and EC estimations in air quality models. In this study, the influence of sampling frequency on the measurement of OC and EC was investigated based on PM2.5 samples collected in Beijing, China. Our results suggest that the negative sampling artifact of a bare quartz filter could be remarkably enhanced due to the uptake of water vapor by the filter medium. We also demonstrate that increasing sampling duration does not necessarily reduce the impact of positive sampling artifact, although it will enhance the analytical artifact. Due to the effect of the analytical artifact, EC concentrations of 48 h averaged samples were about 15 % lower than results from 24 h averaged ones. In addition, it was found that with the increase of sampling duration, EC results exhibited a stronger dependence on the charring correction method and, meanwhile, optical attenuation (ATN) of EC (retrieved from the carbon analyzer) was more significantly biased by the shadowing effect. Results from this study will be useful for the design of China's PM2.5 chemical speciation monitoring network, which can be expected to be inaugurated in the near future.

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Photocyclization of N-(3-chloro-2-benzo[b]thienocarbonyl)-N'-monosubstituted thioureas

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19862839 ◽

1986 ◽

Vol 51 (12) ◽

pp. 2839-2847 ◽

Cited By ~ 8

Author(s):

Peter Kutschy ◽

Ján Imrich ◽

Juraj Bernát ◽

Pavol Kristian ◽

Oľga Hritzová ◽

...

Keyword(s):

Hydrogen Bond ◽

High Pressure ◽

Intramolecular Hydrogen Bond ◽

Ground States ◽

Phenyl Isothiocyanate ◽

Quartz Filter ◽

Discharge Lamp ◽

Intramolecular Hydrogen

N-(3-Chloro-2-benzo[b]thienocarbonyl)-N'-monosubstituted thioureas, when irradiated with a high-pressure mercury discharge lamp through a pyrex or quartz filter, give the corresponding benzothienothiazine derivatives in lower yields than the analogous N',N'-disubstituted thioureas. The reactivity lowering of the N'-monosubstituted thioureas is ascribed to the intramolecular hydrogen bond C=O...H-N due to which these compounds in their ground states exist in the six-membered cyclic conformation unfavourable for the cyclization. The photolysis of N'-phenylthiourea results - due to a stronger hydrogen bond - in splitting of the molecule to give 3-chlorobenzo[b]thiophene-2-carboxamide and phenyl isothiocyanate.

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Mode Control and Related Studies of VHF Quartz Filter Crystals

IEEE Transactions on Sonics and Ultrasonics ◽

10.1109/t-su.1971.29627 ◽

1971 ◽

Vol 18 (4) ◽

pp. 238-246 ◽

Cited By ~ 5

Author(s):

T.J. Lukaszek

Keyword(s):

Quartz Filter ◽

Mode Control

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Determination of gaseous and particulate carbonyls (glycolaldehyde, hydroxyacetone, glyoxal, methylglyoxal, nonanal and decanal) in the atmosphere at Mt. Tai

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-2725-2013 ◽

2013 ◽

Vol 13 (1) ◽

pp. 2725-2758 ◽

Cited By ~ 2

Author(s):

K. Kawamura ◽

K. Okuzawa ◽

S. G. Aggarwal ◽

H. Irie ◽

Y. Kanaya ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Time Resolved ◽

Quartz Filter ◽

Clear Sky ◽

Carbonyl Derivatives ◽

The North ◽

The North China Plain ◽

Upward Transport

Abstract. Gaseous and particulate semi-volatile carbonyl compounds were determined every three hours in the atmosphere of Mount Tai (elevation, 1534 m) in the North China Plain during 2–5, 23–24 and 25 June, 2006 under a clear sky condition. Using two-step filter cartridge in a series, particulate carbonyls were first collected on a quartz filter and then gaseous carbonyls were collected on a quartz filter impregnated with O-benzylhydroxylamine (BHA). After the two-step derivatization with BHA and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), carbonyl derivatives were measured using a gas chromatography. The gaseous concentrations were obtained as follow: glycolaldehyde (range 0–1271 ng m−3, average 555 ng m−3), hydroxyacetone (0–707 ng m−3, 163 ng m−3), glyoxal (198–1396 ng m−3, 720 ng m−3), methylglyoxal (410–3170 ng m−3, 1376 ng m−3), n-nonanal (0–236 ng m−3, 71 ng m−3), and n-decanal (0–159 ng m−3, 31 ng m−3). These concentrations are among the highest ever reported in the urban and forest atmosphere. We found that gaseous carbonyls are more than 10 times more abundant than particulate carbonyls. Time-resolved variations of carbonyls did not show any a clear diurnal pattern, except for hydroxyacetone. We found that glyoxal, methylglyoxal and glycolaldehyde positively correlated with levoglucosan (a tracer of biomass burning), suggesting that a contribution from field burning of agricultural wastes (wheat crops) is significant for the bifunctional carbonyls in the atmosphere of Mt. Tai. Upward transport of the pollutants to the mountaintop from the low lands in the North China Plain is a major process to control the distributions of carbonyls in the upper atmosphere over Mt. Tai.

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