Journal articles on the topic 'Particle temperature measurement'
To see the other types of publications on this topic, follow the link: Particle temperature measurement.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Particle temperature measurement.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Mathissen, Marcel, Theodoros Grigoratos, Tero Lahde, and Rainer Vogt. "Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer." Atmosphere 10, no. 9 (September 17, 2019): 556. http://dx.doi.org/10.3390/atmos10090556.
Full textAbstract:
Brake wear emissions with a special focus on particle number (PN) concentrations were investigated during a chassis dynamometer measurement campaign. A recently developed, well-characterized, measurement approach was applied to measure brake particles in a semi-closed vehicle setup. Implementation of multiple particle measurement devices allowed for simultaneous measurement of volatile and solid particles. Estimated PN emission factors for volatile and solid particles differed by up to three orders of magnitude with an estimated average solid particle emission factor of 3∙109 # km−1 brake−1 over a representative on-road brake cycle. Unrealistic high brake temperatures may occur and need to be ruled out by comparison with on-road temperature measurements. PN emissions are strongly temperature dependent and this may lead to its overestimation. A high variability for PN emissions was found when volatile particles were not removed. Volatiles were observed under high temperature conditions only which are not representative of normal driving conditions. The coefficient of variation for PN emissions was 1.3 without catalytic stripper and 0.11 with catalytic stripper. Investigation of non-braking sections confirmed that particles may be generated at the brake even if no brakes are applied. These “off-brake-event” emissions contribute up to about 30% to the total brake PM10 emission.
2
Xu, Mindi, and Wei-Ching Li. "Measuring Particles and Bubbles in Process Chemicals at Controlled Temperatures." Journal of the IEST 42, no. 5 (September 14, 1999): 30–35. http://dx.doi.org/10.17764/jiet.42.5.y447143110270456.
Full textAbstract:
Microbubbles in semiconductor manufacturing process chemicals can be produced by mechanical disturbance to the chemicals or by changing the temperature and pressure. Bubbles suspended in liquid are easily miscounted as particles when an optical particle counter is used for measuring particles. A new technique, controlling sample temperature, has been developed. Samples for measuring particles are refrigerated to a temperature that eliminates bubbles and then introduced into a particle counter for measurement. The results from these experiments indicate that sample temperature strongly affects the particle counts due to the bubbles in the liquids. Effective temperatures for bubble suppression in several process chemicals have been selected based on the experiments. To better understand bubble suppression by controlling temperature, theoretical simulations for the microbubbles in the chemicals were conducted at various temperature conditions. The results from the experiments and the theoretical simulations are compared.
3
Flamant, G., N. Fatah, G. Olalde, and D. Hernandez. "Temperature Distribution Near a Heat Exchanger Wall Immersed in High-Temperature Packed and Fluidized Beds." Journal of Heat Transfer 114, no. 1 (February 1, 1992): 50–55. http://dx.doi.org/10.1115/1.2911266.
Full textAbstract:
Experimental results dealing with both particle and gas temperature distribution in the vicinity of a water-cooled wall immersed in fixed and fluidized beds are presented. The measurement of particle temperature is based on the use of a mobile optical fiber connected to a two-color radiometer. The gas temperature is obtained on the basis of the indications of a bare thermocouple. Particle and gas temperature fields are compared in fixed and fluidized beds for alumina and silicon carbide particles. In the fixed bed, temperature differences as large as 300°C between the gas and the solid are measured. In the fluidized bed, temperature decreases of both solid and gas phase are shown for large particle at incipient fluidization. The temperature variation reaches more than 100°C for corundum particles and 200°C in the gas. The temperature distribution in the solid phase is shown to be dependent on the thermophysical properties of the particles (thermal conductivity and emissivity).
4
Nesse Tyssøy, H., D. Heinrich, J. Stadsnes, M. Sørbø, U. P. Hoppe, D. S. Evans, B. P. Williams, and F. Honary. "Upper-mesospheric temperatures measured during intense substorms in the declining phase of the January 2005 solar proton events." Annales Geophysicae 26, no. 9 (September 1, 2008): 2515–29. http://dx.doi.org/10.5194/angeo-26-2515-2008.
Full textAbstract:
Abstract. Temperature measurements from the ALOMAR Weber Na lidar together with cosmic radio noise absorption measurements from IRIS and particle measurements from NOAA 15, 16 and 17 are used to study effects of geomagnetic activity on the polar winter upper-mesospheric temperature. On 21–22 January 2005 we have 14 h of continuous temperature measurement with the Na lidar coinciding with strong geomagnetic activity in the declining phase of one of the hardest and most energetic Solar Proton Event (SPE) of solar cycle 23. According to measurements by the imaging riometer IRIS in northern Finland, the temperature measurements coincide with two periods of increased cosmic radio noise absorption. Particle measurements from the three satellites, NOAA 15, 16 and 17 that pass through and near our region of interest confirm that the absorption events are probably due to particle precipitation and not due to changes in e.g. the electron recombination coefficient. The measured temperature variation at 85 and 90 km is dominated by a 7.6-h wave with downward phase propagation and a vertical wavelength of approximately 10 km. Assuming that the wave is due to a lower altitude source independent of the particle precipitation, we do not find any temperature modification that seems to be related to the absorption events. The average temperature is larger than expected above 90 km based on MSIS and the monthly mean from falling spheres, which could be due to particle precipitation and Joule heating prior to our measurement period. There is also a possibility that the identified wave phenomenon is an effect of the geomagnetic activity itself. Earlier studies have reported of similar wavelike structures in wind observations made by the EISCAT VHF radar during SPEs, and found it conceivable that the wave could be excited by the effect of energetic particles precipitating into the mesosphere.
5
Vetter, A. A. "Sensitivity of the Acoustical Resonance Measurement of Particle Loading in Gas-Solids Flow." Journal of Engineering for Gas Turbines and Power 110, no. 2 (April 1, 1988): 197–200. http://dx.doi.org/10.1115/1.3240103.
Full textAbstract:
Measurement of the frequency of transverse acoustic resonances of a duct can determine the mass loading and size of particles fluidized by a gas phase. A first-order perturbation-iteration acoustic analysis is applied to determine the sensitivity of this two-phase flow measurement, termed the Acoustical Resonance Measurement, to variations in particle size, particle size dispersion, particle heat capacity, temperature, and pressure for the application of pulverized coal fluidized by air.
6
Rassat, Scot D., and E. James Davis. "Temperature Measurement of Single Levitated Microparticles Using Stokes/Anti-Stokes Raman Intensity Ratios." Applied Spectroscopy 48, no. 12 (December 1994): 1498–505. http://dx.doi.org/10.1366/0003702944027921.
Full textAbstract:
A method has been developed to determine the temperature of single microparticles levitated in an electrodynamic balance. Particle temperatures were ascertained from the measured intensities of the Stokes and anti-Stokes Raman spectra. Temperatures near ambient were obtained for titanium dioxide and calcium nitrate microparticles with the use of a Raman-based calibration of the optical system to correct for wavelength-dependent effects. Higher temperatures were also measured with the use of a carbon dioxide infrared laser to electromagnetically heat the particle. In an effort to minimize particle instabilities caused by the heating beam, the Gaussian intensity profile of the beam was modified with an axicon beam expander to produce a doughnut-like intensity distribution. The temperature measurement technique and quantitative Raman composition analysis were applied to study dehydration of a calcium nitrate tetrahydrate particle.
7
Fincke, J. R., W. D. Swank, C. L. Jeffery, and C. A. Mancuso. "Simultaneous measurement of particle size, velocity and temperature." Measurement Science and Technology 4, no. 5 (May 1, 1993): 559–65. http://dx.doi.org/10.1088/0957-0233/4/5/003.
Full text
8
Fincke, J. R., D. C. Haggard, and W. D. Swank. "Particle Temperature Measurement in the Thermal Spray Process." Journal of Thermal Spray Technology 10, no. 2 (June 1, 2001): 255–66. http://dx.doi.org/10.1361/105996301770349358.
Full text
9
Fincke, J. R., C. L. Jeffery, and S. B. Englert. "In-flight measurement of particle size and temperature." Journal of Physics E: Scientific Instruments 21, no. 4 (April 1988): 367–70. http://dx.doi.org/10.1088/0022-3735/21/4/005.
Full text
10
Someya, Satoshi, Masao Iida, and Koji Okamoto. "C111 Development of Temperature Sensitive Particle for the temperature measurement in fluids." Proceedings of the Thermal Engineering Conference 2007 (2007): 97–98. http://dx.doi.org/10.1299/jsmeted.2007.97.
Full text
11
Hiranuma, N., S. Augustin-Bauditz, H. Bingemer, C. Budke, J. Curtius, A. Danielczok, K. Diehl, et al. "A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques." Atmospheric Chemistry and Physics 15, no. 5 (March 6, 2015): 2489–518. http://dx.doi.org/10.5194/acp-15-2489-2015.
Full textAbstract:
Abstract. Immersion freezing is the most relevant heterogeneous ice nucleation mechanism through which ice crystals are formed in mixed-phase clouds. In recent years, an increasing number of laboratory experiments utilizing a variety of instruments have examined immersion freezing activity of atmospherically relevant ice-nucleating particles. However, an intercomparison of these laboratory results is a difficult task because investigators have used different ice nucleation (IN) measurement methods to produce these results. A remaining challenge is to explore the sensitivity and accuracy of these techniques and to understand how the IN results are potentially influenced or biased by experimental parameters associated with these techniques. Within the framework of INUIT (Ice Nuclei Research Unit), we distributed an illite-rich sample (illite NX) as a representative surrogate for atmospheric mineral dust particles to investigators to perform immersion freezing experiments using different IN measurement methods and to obtain IN data as a function of particle concentration, temperature (T), cooling rate and nucleation time. A total of 17 measurement methods were involved in the data intercomparison. Experiments with seven instruments started with the test sample pre-suspended in water before cooling, while 10 other instruments employed water vapor condensation onto dry-dispersed particles followed by immersion freezing. The resulting comprehensive immersion freezing data set was evaluated using the ice nucleation active surface-site density, ns, to develop a representative ns(T) spectrum that spans a wide temperature range (−37 °C < T < −11 °C) and covers 9 orders of magnitude in ns. In general, the 17 immersion freezing measurement techniques deviate, within a range of about 8 °C in terms of temperature, by 3 orders of magnitude with respect to ns. In addition, we show evidence that the immersion freezing efficiency expressed in ns of illite NX particles is relatively independent of droplet size, particle mass in suspension, particle size and cooling rate during freezing. A strong temperature dependence and weak time and size dependence of the immersion freezing efficiency of illite-rich clay mineral particles enabled the ns parameterization solely as a function of temperature. We also characterized the ns(T) spectra and identified a section with a steep slope between −20 and −27 °C, where a large fraction of active sites of our test dust may trigger immersion freezing. This slope was followed by a region with a gentler slope at temperatures below −27 °C. While the agreement between different instruments was reasonable below ~ −27 °C, there seemed to be a different trend in the temperature-dependent ice nucleation activity from the suspension and dry-dispersed particle measurements for this mineral dust, in particular at higher temperatures. For instance, the ice nucleation activity expressed in ns was smaller for the average of the wet suspended samples and higher for the average of the dry-dispersed aerosol samples between about −27 and −18 °C. Only instruments making measurements with wet suspended samples were able to measure ice nucleation above −18 °C. A possible explanation for the deviation between −27 and −18 °C is discussed. Multiple exponential distribution fits in both linear and log space for both specific surface area-based ns(T) and geometric surface area-based ns(T) are provided. These new fits, constrained by using identical reference samples, will help to compare IN measurement methods that are not included in the present study and IN data from future IN instruments.
12
Xu, Guangwen, Takahiro Murakami, Toshiyuki Suda, Yoshiaki Matsuzawa, and Hidehisa Tani. "Particle circulation rate in high-temperature CFB: Measurement and temperature influence." AIChE Journal 52, no. 10 (2006): 3626–30. http://dx.doi.org/10.1002/aic.10959.
Full text
13
FUJITANI, YUJI, and TAKAHIRO KOBAYASHI. "MEASUREMENT OF AEROSOLS IN ENGINEERED NANOMATERIALS FACTORIES FOR RISK ASSESSMENT." Nano 03, no. 04 (August 2008): 245–49. http://dx.doi.org/10.1142/s179329200800109x.
Full textAbstract:
In relation to potential health risks, there is little available information on exposure to aerosols containing nanometer-size particles in work environments in factories producing engineered nanomaterials. We measured the concentrations and size distributions of particles of nanometer-sized to coarse-sized particles in an engineered carbon nanomaterial factory and a titanium dioxide factory. In addition, particles were collected with a quartz fiber filter in the engineered carbon nanomaterial factory, and their morphology was examined by scanning electron microscopy and their carbon composition was examined with a carbon analyzer. In the carbon nanomaterial factory, the particle number increased to more than 105 cm-3 when a vacuum cleaner was used to clean the inside of the producing device, and the particle number increased for particles with a diameter of about 100 nm compared with the background. This is the only case an increase in particle numbers is observed during this measurement. The emitted particles appear to consist of agglomerates of carbon nanomaterial particles smaller than 100 nm. The major fraction was the EC3 fraction (EC: elemental carbon; combustion at 800°C in a 98:2 He / O 2 atmosphere), which is a minor fraction in diesel engine particulate matter. This suggests that the combustion temperature can be used to differentiate atmospheric particulate matter from engineered carbon material. Personal sampling conducted in addition to stationary measurements in the titanium dioxide factory indicated that stationary measurements can be used to generate representative data on the basis of the particle number but not the particle mass.
14
Guo, Qiuting, Zheng Guo, Yang Tao, Zhao Zhang, Jun Lin, Jin Zuo, and Guangyuan Liu. "Supersonic gas flow impacting approach for solid-state synthesis at room-temperature: Temperature measurement." International Journal of Modern Physics B 34, no. 14n16 (June 2, 2020): 2040100. http://dx.doi.org/10.1142/s0217979220401001.
Full textAbstract:
Solid-state synthesis based on supersonic gas flow impingement at room-temperature is an alternative approach to traditional mechanochemical preparation. The supersonic airflow is generated by a convergent-diffusion nozzle with a design Mach number of 3.0. The solid material particles from the suction pipe in the coaxial nozzle can get very high kinetic energy in microseconds. Then the particles impact the target or collide with each other to achieve the transfer of kinetic energy to thermal or chemical energy. We utilize the infrared technology to successfully measure the solid particles’ temperature while they impact the target after gathered energy from the supersonic air gas. The results show that the average temperature of the silicon particles with an average particle diameter of 150 [Formula: see text]m after impacting the target is about [Formula: see text]C, and some of the temperature exceed [Formula: see text]C. It dedicates that the kinetic energy of the particles during the collision translate into internal energy indeed. The work of this paper lays a good foundation for further research on the low-temperature solid-phase reaction processes.
15
Gkatzelis, G. I., D. K. Papanastasiou, K. Florou, C. Kaltsonoudis, E. Louvaris, and S. N. Pandis. "Measurement of nonvolatile particle number size distribution." Atmospheric Measurement Techniques 9, no. 1 (January 18, 2016): 103–14. http://dx.doi.org/10.5194/amt-9-103-2016.
Full textAbstract:
Abstract. An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50–60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15–20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.
16
Clausen, Sønnik, and Lasse Holst Sørensen. "Measurement of Single Moving Particle Temperatures with an FT-IR Spectrometer." Applied Spectroscopy 50, no. 9 (September 1996): 1103–11. http://dx.doi.org/10.1366/0003702963905150.
Full textAbstract:
A conventional scanning FT-IR spectrometer is used to measure the blackbody radiation through a rapidly moving pinhole in an experiment simulating a flying hot particle. The effects and errors from source movements are analyzed and verified through experiments. The importance of the scanning velocity, phase-correction method, and temperature variations during scanning is investigated. It is shown that a calibration of the system at one temperature is sufficient for accurate spectral radiance and temperature measurements throughout a broad temperature range. The temperature errors are reduced by a factor of 2–10 compared with results from a typical two-color pyrometer. A novel method is presented for measuring emission spectra from single moving particles passing the field of view of the spectrometer in a random manner.
17
DeMott, Paul J., Ottmar Möhler, Daniel J. Cziczo, Naruki Hiranuma, Markus D. Petters, Sarah S. Petters, Franco Belosi, et al. "The Fifth International Workshop on Ice Nucleation phase 2 (FIN-02): laboratory intercomparison of ice nucleation measurements." Atmospheric Measurement Techniques 11, no. 11 (November 19, 2018): 6231–57. http://dx.doi.org/10.5194/amt-11-6231-2018.
Full textAbstract:
Abstract. The second phase of the Fifth International Ice Nucleation Workshop (FIN-02) involved the gathering of a large number of researchers at the Karlsruhe Institute of Technology's Aerosol Interactions and Dynamics of the Atmosphere (AIDA) facility to promote characterization and understanding of ice nucleation measurements made by a variety of methods used worldwide. Compared to the previous workshop in 2007, participation was doubled, reflecting a vibrant research area. Experimental methods involved sampling of aerosol particles by direct processing ice nucleation measuring systems from the same volume of air in separate experiments using different ice nucleating particle (INP) types, and collections of aerosol particle samples onto filters or into liquid for sharing amongst measurement techniques that post-process these samples. In this manner, any errors introduced by differences in generation methods when samples are shared across laboratories were mitigated. Furthermore, as much as possible, aerosol particle size distribution was controlled so that the size limitations of different methods were minimized. The results presented here use data from the workshop to assess the comparability of immersion freezing measurement methods activating INPs in bulk suspensions, methods that activate INPs in condensation and/or immersion freezing modes as single particles on a substrate, continuous flow diffusion chambers (CFDCs) directly sampling and processing particles well above water saturation to maximize immersion and subsequent freezing of aerosol particles, and expansion cloud chamber simulations in which liquid cloud droplets were first activated on aerosol particles prior to freezing. The AIDA expansion chamber measurements are expected to be the closest representation to INP activation in atmospheric cloud parcels in these comparisons, due to exposing particles freely to adiabatic cooling. The different particle types used as INPs included the minerals illite NX and potassium feldspar (K-feldspar), two natural soil dusts representative of arable sandy loam (Argentina) and highly erodible sandy dryland (Tunisia) soils, respectively, and a bacterial INP (Snomax®). Considered together, the agreement among post-processed immersion freezing measurements of the numbers and fractions of particles active at different temperatures following bulk collection of particles into liquid was excellent, with possible temperature uncertainties inferred to be a key factor in determining INP uncertainties. Collection onto filters for rinsing versus directly into liquid in impingers made little difference. For methods that activated collected single particles on a substrate at a controlled humidity at or above water saturation, agreement with immersion freezing methods was good in most cases, but was biased low in a few others for reasons that have not been resolved, but could relate to water vapor competition effects. Amongst CFDC-style instruments, various factors requiring (variable) higher supersaturations to achieve equivalent immersion freezing activation dominate the uncertainty between these measurements, and for comparison with bulk immersion freezing methods. When operated above water saturation to include assessment of immersion freezing, CFDC measurements often measured at or above the upper bound of immersion freezing device measurements, but often underestimated INP concentration in comparison to an immersion freezing method that first activates all particles into liquid droplets prior to cooling (the PIMCA-PINC device, or Portable Immersion Mode Cooling chAmber–Portable Ice Nucleation Chamber), and typically slightly underestimated INP number concentrations in comparison to cloud parcel expansions in the AIDA chamber; this can be largely mitigated when it is possible to raise the relative humidity to sufficiently high values in the CFDCs, although this is not always possible operationally. Correspondence of measurements of INPs among direct sampling and post-processing systems varied depending on the INP type. Agreement was best for Snomax® particles in the temperature regime colder than −10 ∘C, where their ice nucleation activity is nearly maximized and changes very little with temperature. At temperatures warmer than −10 ∘C, Snomax® INP measurements (all via freezing of suspensions) demonstrated discrepancies consistent with previous reports of the instability of its protein aggregates that appear to make it less suitable as a calibration INP at these temperatures. For Argentinian soil dust particles, there was excellent agreement across all measurement methods; measures ranged within 1 order of magnitude for INP number concentrations, active fractions and calculated active site densities over a 25 to 30 ∘C range and 5 to 8 orders of corresponding magnitude change in number concentrations. This was also the case for all temperatures warmer than −25 ∘C in Tunisian dust experiments. In contrast, discrepancies in measurements of INP concentrations or active site densities that exceeded 2 orders of magnitude across a broad range of temperature measurements found at temperatures warmer than −25 ∘C in a previous study were replicated for illite NX. Discrepancies also exceeded 2 orders of magnitude at temperatures of −20 to −25 ∘C for potassium feldspar (K-feldspar), but these coincided with the range of temperatures at which INP concentrations increase rapidly at approximately an order of magnitude per 2 ∘C cooling for K-feldspar. These few discrepancies did not outweigh the overall positive outcomes of the workshop activity, nor the future utility of this data set or future similar efforts for resolving remaining measurement issues. Measurements of the same materials were repeatable over the time of the workshop and demonstrated strong consistency with prior studies, as reflected by agreement of data broadly with parameterizations of different specific or general (e.g., soil dust) aerosol types. The divergent measurements of the INP activity of illite NX by direct versus post-processing methods were not repeated for other particle types, and the Snomax® data demonstrated that, at least for a biological INP type, there is no expected measurement bias between bulk collection and direct immediately processed freezing methods to as warm as −10 ∘C. Since particle size ranges were limited for this workshop, it can be expected that for atmospheric populations of INPs, measurement discrepancies will appear due to the different capabilities of methods for sampling the full aerosol size distribution, or due to limitations on achieving sufficient water supersaturations to fully capture immersion freezing in direct processing instruments. Overall, this workshop presents an improved picture of present capabilities for measuring INPs than in past workshops, and provides direction toward addressing remaining measurement issues.
18
Mohapatra, Sasmita, Nabakumar Pramanik, Sudip K. Ghosh, and Panchanan Pramanik. "Synthesis and Characterization of Ultrafine Poly(vinylalcohol phosphate) Coated Magnetite Nanoparticles." Journal of Nanoscience and Nanotechnology 6, no. 3 (March 1, 2006): 823–29. http://dx.doi.org/10.1166/jnn.2006.117.
Full textAbstract:
Nanosized magnetite (Fe3O4) particles showing superparamagnetism at room temperature have been prepared by controlled coprecipitation of Fe2+ and Fe3+ in presence of highly hydrophilic poly(vinylalcohol phosphate)(PVAP). The impact of polymer concentration on particle size, size distribution, colloidal stability, and magnetic property has been extensively studied. The aqueous suspension of magnetite, prepared using 1% PVAP solution is stable for four weeks at pH 5–8. X-ray diffractograms show the formation of nanocrystalline inverse spinel phase magnetite. Transmission Electron Microscopy confirmed well dispersed cubic magnetite particles of size of about 5.8 nm. Dynamic Light Scattering measurement shows narrow distribution of hydrodynamic size of particle aggregates. Infrared spectra of samples show strong Fe—O—P bond on the oxide surface. UV-visible studies show aqueous dispersion of magnetite formed by using 1% PVAP solution is stable at least for four weeks without any detoriation of particle size. Magnetization measurements at room temperature show superparamagnetic nature of polymer coated magnetite nanoparticles.
19
Sahu†, Ranajit, Paul S. Northrop§, Richard C. Flagan‡, and George R. Gavalas§. "Char Combustion: Measurement and Analysis of Particle Temperature Histories." Combustion Science and Technology 60, no. 1-3 (July 1988): 215–30. http://dx.doi.org/10.1080/00102208808923985.
Full text
20
Omiya, Satoshi, Atsushi Sato, Kenji Kosugi, and Shigeto Mochizuki. "Estimation of the electrostatic charge of individual blowing-snow particles by wind tunnel experiment." Annals of Glaciology 52, no. 58 (2011): 148–52. http://dx.doi.org/10.3189/172756411797252167.
Full textAbstract:
AbstarctThere are some reports on the measurement of the charge-to-mass ratio of blowing-snow particles, but there are few studies concerned with individual snow-particle charge. We measured the charge-to-mass ratios using snow particles selected according to size, and discussed individual charges. Experiments were conducted in a cryogenic wind tunnel. Charge-to-mass ratios measured in our experiment were all negative and their absolute values tended to increase with a decrease in particle diameter. Individual snow-particle charges were calculated from the average of particle diameter distributions. The charges were all approximated by the power function of diameter at each temperature. Assuming that the coefficient of these approximations is a function of air temperature, we could easily predict the individual snow-particle charge.
21
Gkatzelis, G. I., D. K. Papanastasiou, K. Florou, C. Kaltsonoudis, E. Louvaris, and S. N. Pandis. "Measurement of non-volatile particle number size distribution." Atmospheric Measurement Techniques Discussions 8, no. 6 (June 25, 2015): 6355–93. http://dx.doi.org/10.5194/amtd-8-6355-2015.
Full textAbstract:
Abstract. An experimental methodology was developed to measure the non-volatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a non-volatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol, OA (40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50–60 % of the particles had a non-volatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon (BC) with an 80 % contribution, while OA was responsible for another 15–20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.
22
Safitri, Yulia, Irwan Irwan, and Cut Aja Rahmawati. "Pengaruh Penambahan Surfaktan Gum Arabic Terhadap Sifat Fisik dan Stabilitas Fluida Nano Titania (TiO2)." Jurnal Teknologi 21, no. 1 (April 22, 2021): 26. http://dx.doi.org/10.30811/teknologi.v21i1.2207.
Full textAbstract:
This study aims to examine the physical properties of titania (TiO2) by adding arabic gum surfactants to obtain stable nanofluid. Nano titania fluid preparation was carried out by dispersing titania nanoparticles and arabic gum in a homogenizer for 3 hours with particle variations in fraction volume and arabic gum surfactant concentration. The study was carried out by varying the volume of the particle fraction at 0.1%; 0.2%; 0.3%; 0.4% and 0.5% and arabic gum surfactant concentrations at 1%; 2%; 3%; 4%; and 5%. Measurements are also made at a temperature variation of 30 OC; 40 OC; and 50 OC. Measurement of physical properties is carried out by measuring the properties of electrical conductivity, density, viscosity, and stability of titania nanofluid. The measurement results indicate that the higher the concentration of surfactant and the volume fraction of particles, the electrical conductivity, density, and viscosity of nano titania fluid is increasing. Increased temperature will reduce the viscosity of titania nanofluid.
23
Mei, Fan, Steven Spielman, Susanne Hering, Jian Wang, Mikhail S. Pekour, Gregory Lewis, Beat Schmid, Jason Tomlinson, and Maynard Havlicek. "Simulation-aided characterization of a versatile water-based condensation particle counter for atmospheric airborne research." Atmospheric Measurement Techniques 14, no. 11 (November 23, 2021): 7329–40. http://dx.doi.org/10.5194/amt-14-7329-2021.
Full textAbstract:
Abstract. Capturing the vertical profiles and horizontal variations of atmospheric aerosols often requires accurate airborne measurements. With the advantage of avoiding health and safety concerns related to the use of butanol or other chemicals, water-based condensation particle counters have emerged to provide measurements under various environments. However, airborne deployments are relatively rare due to the lack of instrument characterization under reduced pressure at flight altitudes. This study investigates the performance of a commercial “versatile” water-based condensation particle counter (vWCPC, model 3789, TSI, Shoreview, MN, USA) under various ambient pressure conditions (500–920 hPa) with a wide range of particle total number concentrations (1500–70 000 cm−3). The effect of conditioner temperature on vWCPC 3789 performance at low pressure is examined through numerical simulation and laboratory experiments. We show that the default instrument temperature setting of 30 ∘C for the conditioner is not suitable for airborne measurement and that the optimal conditioner temperature for low-pressure operation is 27∘. Under the optimal conditioner temperature (27∘), the 7 nm cut-off size is also maintained. Additionally, we show that insufficient droplet growth becomes more significant under the low-pressure operation. The counting efficiency of the vWCPC 3789 can vary up to 20 % for particles of different chemical compositions (e.g., ammonium sulfate and sucrose particles). However, such variation is independent of pressure.
24
Nicolaou, Georgios, Robert Wicks, George Livadiotis, Daniel Verscharen, Christopher Owen, and Dhiren Kataria. "Determining the Bulk Parameters of Plasma Electrons from Pitch-Angle Distribution Measurements." Entropy 22, no. 1 (January 16, 2020): 103. http://dx.doi.org/10.3390/e22010103.
Full textAbstract:
Electrostatic analysers measure the flux of plasma particles in velocity space and determine their velocity distribution function. There are occasions when science objectives require high time-resolution measurements, and the instrument operates in short measurement cycles, sampling only a portion of the velocity distribution function. One such high-resolution measurement strategy consists of sampling the two-dimensional pitch-angle distributions of the plasma particles, which describes the velocities of the particles with respect to the local magnetic field direction. Here, we investigate the accuracy of plasma bulk parameters from such high-resolution measurements. We simulate electron observations from the Solar Wind Analyser’s (SWA) Electron Analyser System (EAS) on board Solar Orbiter. We show that fitting analysis of the synthetic datasets determines the plasma temperature and kappa index of the distribution within 10% of their actual values, even at large heliocentric distances where the expected solar wind flux is very low. Interestingly, we show that although measurement points with zero counts are not statistically significant, they provide information about the particle distribution function which becomes important when the particle flux is low. We also examine the convergence of the fitting algorithm for expected plasma conditions and discuss the sources of statistical and systematic uncertainties.
25
Hiranuma, N., S. Augustin-Bauditz, H. Bingemer, C. Budke, J. Curtius, A. Danielczok, K. Diehl, et al. "A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of seventeen ice nucleation measurement techniques." Atmospheric Chemistry and Physics Discussions 14, no. 15 (August 28, 2014): 22045–116. http://dx.doi.org/10.5194/acpd-14-22045-2014.
Full textAbstract:
Abstract. Immersion freezing is the most relevant heterogeneous ice nucleation mechanism through which ice crystals are formed in mixed-phase clouds. In recent years, an increasing number of laboratory experiments utilizing a variety of instruments have examined immersion freezing activity of atmospherically relevant ice nucleating particles (INPs). However, an inter-comparison of these laboratory results is a difficult task because investigators have used different ice nucleation (IN) measurement methods to produce these results. A remaining challenge is to explore the sensitivity and accuracy of these techniques and to understand how the IN results are potentially influenced or biased by experimental parameters associated with these techniques. Within the framework of INUIT (Ice Nucleation research UnIT), we distributed an illite rich sample (illite NX) as a representative surrogate for atmospheric mineral dust particles to investigators to perform immersion freezing experiments using different IN measurement methods and to obtain IN data as a function of particle concentration, temperature (T), cooling rate and nucleation time. Seventeen measurement methods were involved in the data inter-comparison. Experiments with seven instruments started with the test sample pre-suspended in water before cooling, while ten other instruments employed water vapor condensation onto dry-dispersed particles followed by immersion freezing. The resulting comprehensive immersion freezing dataset was evaluated using the ice nucleation active surface-site density (ns) to develop a representative ns(T) spectrum that spans a wide temperature range (−37 °C < T < −11 °C) and covers nine orders of magnitude in ns. Our inter-comparison results revealed a discrepancy between suspension and dry-dispersed particle measurements for this mineral dust. While the agreement was good below ~ −26 °C, the ice nucleation activity, expressed in ns, was smaller for the wet suspended samples and higher for the dry-dispersed aerosol samples between about −26 and −18 °C. Only instruments making measurement techniques with wet suspended samples were able to measure ice nucleation above −18 °C. A possible explanation for the deviation between −26 and −18 °C is discussed. In general, the seventeen immersion freezing measurement techniques deviate, within the range of about 7 °C in terms of temperature, by three orders of magnitude with respect to ns. In addition, we show evidence that the immersion freezing efficiency (i.e., ns) of illite NX particles is relatively independent on droplet size, particle mass in suspension, particle size and cooling rate during freezing. A strong temperature-dependence and weak time- and size-dependence of immersion freezing efficiency of illite-rich clay mineral particles enabled the ns parameterization solely as a function of temperature. We also characterized the ns (T) spectra, and identified a section with a steep slope between −20 and −27 °C, where a large fraction of active sites of our test dust may trigger immersion freezing. This slope was followed by a region with a gentler slope at temperatures below −27 °C. A multiple exponential distribution fit is expressed as ns(T) = exp(23.82 × exp(−exp(0.16 × (T + 17.49))) + 1.39) based on the specific surface area and ns(T) = exp(25.75 × exp(−exp(0.13 × (T + 17.17))) + 3.34) based on the geometric area (ns and T in m−2 and °C, respectively). These new fits, constrained by using an identical reference samples, will help to compare IN measurement methods that are not included in the present study and, thereby, IN data from future IN instruments.
26
Crumeyrolle, Suzanne, Jenni S. S. Kontkanen, Clémence Rose, Alejandra Velazquez Garcia, Eric Bourrianne, Maxime Catalfamo, Véronique Riffault, et al. "Measurement report: Atmospheric new particle formation at a peri-urban site in Lille, northern France." Atmospheric Chemistry and Physics 23, no. 1 (January 5, 2023): 183–201. http://dx.doi.org/10.5194/acp-23-183-2023.
Full textAbstract:
Abstract. Formation of ultrafine particles (UFPs) in the urban atmosphere is expected to be less favored than in the rural atmosphere due to the high existing particle surface area acting as a sink for newly formed particles. Despite large condensation sink (CS) values, previous comparative studies between rural and urban sites reported higher frequency of new particle formation (NPF) events over urban sites in comparison to background sites as well as higher particle formation and growth rates attributed to the higher concentration of condensable species. The present study aims at a better understanding the environmental factors favoring, or disfavoring, atmospheric NPF over Lille, a large city in the north of France, and to analyze their impact on particle number concentration using a 4-year long-term dataset. The results highlight a strong seasonal variation of NPF occurrences with a maximum frequency observed during spring (27 events) and summer (53 events). It was found that high temperature (T>295 K), low relative humidity (RH <45 %), and high solar radiation are ideal to observe NPF events over Lille. Relatively high CS values (i.e., ∼2×10-2 s−1) are reported during event days suggesting that high CS does not inhibit the occurrence of NPF over the ATmospheric Observations in LiLLE (ATOLL) station. Moreover, the particle growth rate was positively correlated with temperatures most probably due to higher emission of precursors. Finally, the nucleation strength factor (NSF) was calculated to highlight the impact of those NPF events on particle number concentrations. NSF reached a maximum of four in summer, evidencing a huge contribution of NPF events to particle number concentration at this time of the year.
27
Garimella, Sarvesh, Daniel A. Rothenberg, Martin J. Wolf, Robert O. David, Zamin A. Kanji, Chien Wang, Michael Rösch, and Daniel J. Cziczo. "Uncertainty in counting ice nucleating particles with continuous flow diffusion chambers." Atmospheric Chemistry and Physics 17, no. 17 (September 14, 2017): 10855–64. http://dx.doi.org/10.5194/acp-17-10855-2017.
Full textAbstract:
Abstract. This study investigates the measurement of ice nucleating particle (INP) concentrations and sizing of crystals using continuous flow diffusion chambers (CFDCs). CFDCs have been deployed for decades to measure the formation of INPs under controlled humidity and temperature conditions in laboratory studies and by ambient aerosol populations. These measurements have, in turn, been used to construct parameterizations for use in models by relating the formation of ice crystals to state variables such as temperature and humidity as well as aerosol particle properties such as composition and number. We show here that assumptions of ideal instrument behavior are not supported by measurements made with a commercially available CFDC, the SPectrometer for Ice Nucleation (SPIN), and the instrument on which it is based, the Zurich Ice Nucleation Chamber (ZINC). Non-ideal instrument behavior, which is likely inherent to varying degrees in all CFDCs, is caused by exposure of particles to different humidities and/or temperatures than predicated from instrument theory of operation. This can result in a systematic, and variable, underestimation of reported INP concentrations. We find here variable correction factors from 1.5 to 9.5, consistent with previous literature values. We use a machine learning approach to show that non-ideality is most likely due to small-scale flow features where the aerosols are combined with sheath flows. Machine learning is also used to minimize the uncertainty in measured INP concentrations. We suggest that detailed measurement, on an instrument-by-instrument basis, be performed to characterize this uncertainty.
28
Spjut, R. E., A. F. Sarofim, and J. P. Longwell. "Laser heating and particle temperature measurement in an electrodynamic balance." Langmuir 1, no. 3 (May 1985): 355–60. http://dx.doi.org/10.1021/la00063a016.
Full text
29
Adachi, S., H. Totsuji, K. Takahashi, Y. Hayashi, and M. Takayanagi. "Particle temperature measurement using pair distribution function in complex plasmas." Journal of Physics: Conference Series 327 (December 6, 2011): 012043. http://dx.doi.org/10.1088/1742-6596/327/1/012043.
Full text
30
Drobyshevskii, A. S., and A. B. Gots. "Measurement of particle velocity in a high-temperature gas stream." Soviet Powder Metallurgy and Metal Ceramics 24, no. 2 (February 1985): 132–34. http://dx.doi.org/10.1007/bf00799717.
Full text
31
Borzone, L. A., and C. D. Riquelme. "THE MEASUREMENT OF PARTICLE TEMPERATURE IN A FLUID1ZED BED DRYER." Drying Technology 15, no. 5 (May 1997): 1593–601. http://dx.doi.org/10.1080/07373939708917310.
Full text
32
Vandličkova, Miroslava, Iveta Markova, Katarina Holla, and Stanislava Gašpercová. "Evaluation of Marblewood Dust’s (Marmaroxylon racemosum) Effect on Ignition Risk." Applied Sciences 11, no. 15 (July 26, 2021): 6874. http://dx.doi.org/10.3390/app11156874.
Full textAbstract:
The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size < 100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).
33
Bertram, T. H., J. A. Thornton, and T. P. Riedel. "An experimental technique for the direct measurement of N<sub>2</sub>O<sub>5</sub> reactivity on ambient particles." Atmospheric Measurement Techniques Discussions 2, no. 2 (March 4, 2009): 689–723. http://dx.doi.org/10.5194/amtd-2-689-2009.
Full textAbstract:
Abstract. An experimental approach for the direct measurement of trace gas reactivity on ambient aerosol particles has been developed. The method utilizes a newly designed entrained aerosol flow reactor coupled to a custom-built chemical ionization mass spectrometer. The experimental method is described via application to the measurement of the N2O5 reaction probability, γ(N2O5). Laboratory investigations on well characterized aerosol particles show that measurements of γ(N2O5) observed with this technique are in agreement with previous observations, using conventional flow tube methods, to within ±20% at atmospherically relevant particle surface area concentrations (0–1000 μm2 cm−3). Uncertainty in the measured γ(N2O5) is discussed in the context of fluctuations in potential ambient biases (e.g., temperature, relative humidity and trace gas loadings). Under ambient operating conditions we estimate a single-point uncertainty in γ(N2O5) that ranges between ±(1.3×10−2+0.2×γ(N2O5)), and ±(1.3×10−3+0.2×γ(N2O5)) for particle surface area concentrations of 100 to 1000 μm2 cm−3, respectively. Examples from both laboratory investigations and field observations are included alongside discussion of future applications for the reactivity measurement and optimal deployment locations and conditions.
34
Bertram, T. H., J. A. Thornton, and T. P. Riedel. "An experimental technique for the direct measurement of N<sub>2</sub>O<sub>5</sub> reactivity on ambient particles." Atmospheric Measurement Techniques 2, no. 1 (June 16, 2009): 231–42. http://dx.doi.org/10.5194/amt-2-231-2009.
Full textAbstract:
Abstract. An experimental approach for the direct measurement of trace gas reactivity on ambient aerosol particles has been developed. The method utilizes a newly designed entrained aerosol flow reactor coupled to a custom-built chemical ionization mass spectrometer. The experimental method is described via application to the measurement of the N2O5 reaction probability, γ (N2O5). Laboratory investigations on well characterized aerosol particles show that measurements of γ (N2O5) observed with this technique are in agreement with previous observations, using conventional flow tube methods, to within ±20% at atmospherically relevant particle surface area concentrations (0–1000 μm2 cm−3). Uncertainty in the measured γ (N2O5) is discussed in the context of fluctuations in potential ambient biases (e.g., temperature, relative humidity and trace gas loadings). Under ambient operating conditions we estimate a single-point uncertainty in γ (N2O5) that ranges between ± (1.3×10-2 + 0.2×γ (N2O5)), and ± (1.3×10-3 + 0.2×γ (N2O5)) for particle surface area concentrations of 100 to 1000 μm2 cm−3, respectively. Examples from both laboratory investigations and field observations are included alongside discussion of future applications for the reactivity measurement and optimal deployment locations and conditions.
35
Schiemann, M., V. Scherer, and S. Wirtz. "Optical Coal Particle Temperature Measurement under Oxy-Fuel Conditions: Measurement Methodology and Initial Results." Chemical Engineering & Technology 32, no. 12 (December 2009): 2000–2004. http://dx.doi.org/10.1002/ceat.200900354.
Full text
36
Moroni, M., and A. Cenedese. "Penetrative convection in stratified fluids: velocity and temperature measurements." Nonlinear Processes in Geophysics 13, no. 3 (August 7, 2006): 353–63. http://dx.doi.org/10.5194/npg-13-353-2006.
Full textAbstract:
Abstract. The flux through the interface between a mixing layer and a stable layer plays a fundamental role in characterizing and forecasting the quality of water in stratified lakes and in the oceans, and the quality of air in the atmosphere. The evolution of the mixing layer in a stably stratified fluid body is simulated in the laboratory when "Penetrative Convection" occurs. The laboratory model consists of a tank filled with water and subjected to heating from below. The methods employed to detect the mixing layer growth were thermocouples for temperature data and two image analysis techniques, namely Laser Induced Fluorescence (LIF) and Feature Tracking (FT). LIF allows the mixing layer evolution to be visualized. Feature Tracking is used to detect tracer particle trajectories moving within the measurement volume. Pollutant dispersion phenomena are naturally described in the Lagrangian approach as the pollutant acts as a tag of the fluid particles. The transilient matrix represents one of the possible tools available for quantifying particle dispersion during the evolution of the phenomenon.
37
Gougeon, P., and C. Moreau. "In-flight particle surface temperature measurement: Influence of the plasma light scattered by the particles." Journal of Thermal Spray Technology 2, no. 3 (September 1993): 229–33. http://dx.doi.org/10.1007/bf02650470.
Full text
38
Dibaji, Seyed Ahmad Reza, Berk Oktem, Lee Williamson, Jenna DuMond, Todd Cecil, Jimin P. Kim, Samanthi Wickramasekara, Matthew Myers, and Suvajyoti Guha. "Characterization of aerosols generated by high-power electronic nicotine delivery systems (ENDS): Influence of atomizer, temperature and PG:VG ratios." PLOS ONE 17, no. 12 (December 20, 2022): e0279309. http://dx.doi.org/10.1371/journal.pone.0279309.
Full textAbstract:
The aerosol characteristics of electronic nicotine delivery systems (ENDS) are important parameters in predicting health outcomes since parameters such as aerosol particle size correlate strongly to aerosol delivery and deposition efficiency. However, many studies to date do not account for aerosol aging, which may affect the measurement of ultra-fine particles that typically coagulate or agglomerate during puff development. To reduce aerosol aging, we herein present a unique instrumentation method that combines a) positive pressure ENDS activation and sample collection, b) minimization of both sample tubing length and dilution factors, and c) a high-resolution, electrical low-pressure impactor. This novel approach was applied to systematically investigate the effects of coil design, coil temperature, and propylene glycol to vegetable glycerol ratios on aerosol characteristics including aerosol mass generation, aerosol count generation, and the mass and count size distributions for a high-powered ENDS. Aerosol count measurements revealed high concentrations of ultra-fine particles compared to fine and coarse particles at 200°C, while aerosol mass measurements showed an increase in the overall aerosol mass of fine and coarse particles with increases in temperature and decreases in propylene glycol content. These results provide a better understanding on how various ENDS design parameters affect aerosol characteristics and highlight the need for further research to identify the design parameters that most impact ultra-fine particle generation.
39
Kawahara, Seiichi, Yoshinobu Isono, Keiko Washino, Toshiko Morita, and Yasuyuki Tanaka. "High-Resolution Latex State 13C-NMR Spectroscopy: Part II. Effect of Particle Size and Temperature." Rubber Chemistry and Technology 74, no. 2 (May 1, 2001): 295–302. http://dx.doi.org/10.5254/1.3544951.
Full textAbstract:
Abstract Latex state C-NMR measurements were made for colloidal dispersions of polymer, using the observation conditions similar to those used in solution state measurement. The colloidal dispersion which showed broad and bimodal distributions in particle size was fractionated by centrifugation into four fractions with different volume mean particle diameter ranging from 0.121 to 1.31 µm with narrow and unimodal distributions. The signal to noise ratio, half width and intensity of each resolved carbon resonance for the fractionated dispersions were dependent upon the particle diameter. The intensity of the carbon resonances increased to 100% as the particle diameter decreased and temperature was raised. This is explained with respect to the increase in diffusion coefficient of Brownian motion of the particle. The intensity and the half width of the signals were superimposed against the diffusion coefficient of Brownian motion.
40
Hammann, E., A. Behrendt, F. Le Mounier, and V. Wulfmeyer. "Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)<sup>2</sup> Observational Prototype Experiment." Atmospheric Chemistry and Physics 15, no. 5 (March 12, 2015): 2867–81. http://dx.doi.org/10.5194/acp-15-2867-2015.
Full textAbstract:
Abstract. The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.
41
Waara, M., H. Nilsson, R. Slapak, M. André, and G. Stenberg. "Oxygen ion energization by waves in the high altitude cusp and mantle." Annales Geophysicae 30, no. 9 (September 3, 2012): 1309–14. http://dx.doi.org/10.5194/angeo-30-1309-2012.
Full textAbstract:
Abstract. We present a comparative study of low frequency electric field spectral densities and temperatures observed by the Cluster spacecraft in the high altitude cusp/mantle region. We compare the relation between the O+ temperature and wave intensity at the oxygen gyrofrequency at each measurement point and find a clear correlation. The trend of the correlation agrees with the predictions by both an asymptotic mean-particle theory and a test-particle approach. The perpendicular to parallel temperature ratio is also consistent with the predictions of the asymptotic mean-particle theory. At times the perpendicular temperature is significantly higher than predicted by the models. A simple study of the evolution of the particle distributions (conics) at these altitudes indicates that enhanced perpendicular temperatures would be observed over many RE after heating ceases. Therefore, sporadic intense heating is the likely explanation for cases with high temperature and comparably low wave activity. We observe waves of sufficient amplitude to explain the highest observed temperatures, while the theory in general overestimates the temperature associated with the highest observed wave activity, indicating that such high wave activity is very sporadic.
42
Fincke, J. R., W. D. Swank, and C. L. Jeffery. "Simultaneous measurement of particle size, velocity, and temperature in thermal plasmas." IEEE Transactions on Plasma Science 18, no. 6 (1990): 948–57. http://dx.doi.org/10.1109/27.61509.
Full text
43
Hollis, K., and R. Neiser. "Particle Temperature and Flux Measurement Utilizing a Nonthermal Signal Correction Process." Journal of Thermal Spray Technology 7, no. 3 (September 1, 1998): 392–402. http://dx.doi.org/10.1361/105996398770350873.
Full text
44
Tomeczek, Jerzy, and Juliusz Wójcik. "A method of direct measurement of solid fuel particle ignition temperature." Symposium (International) on Combustion 23, no. 1 (January 1991): 1163–67. http://dx.doi.org/10.1016/s0082-0784(06)80376-0.
Full text
45
Park, Chaehyeong, Myoungki Song, Gyutae Park, Kyunghoon Kim, Taehyoung Lee, Sanguk Lee, Jongtae Lee, and Min-Suk Bae. "Real-World Vehicle Emission Rate of Particle Size Distributions Based on Measurement of Tunnel Flow Coefficient." Applied Sciences 11, no. 2 (January 15, 2021): 794. http://dx.doi.org/10.3390/app11020794.
Full textAbstract:
This study aims to analyze the seasonal number concentrations corresponding to each particle size derived from the measurements of exhausts from approximately seven million vehicles on real-world using a pair of the scanning mobility particle sizer to determine the vehicle emission rate. The actual tunnel flow coefficient was investigated for car emission rate based on the measurements of individual physical parameters (i.e., cross section area and length of the tunnel, tunnel wind speed and traffic volume). The mode of particle diameter according to temperatures in respective seasons exhibited a high correlation together with rapid changes at temperature above the breakthrough point. The temperature acted as major cause of determination of final condensation diameter, which is also dependent on diverse environmental effects comprising particle number concentration. The traffic volume of ordinary cars increased by more than twice as much in the period of Asian New Year, the traffic volume of buses/RVs/trucks decreased by more than 25% during weekdays. As a result, the particle number concentration discharged from a unit vehicle was 6.96 × 1012 N/veh·km during weekdays, and the values of weekends appeared as 6.08 × 1012 N/veh·km. The overall averaged particle number concentration based on the actual seasonal road measurements shows 5.82 × 1012 N/veh·km.
46
Parekh, Kinnari, R. V. Upadhyay, and V. K. Aswal. "Monodispersed Magnetic Fluids: Synthesis and Characterization." Solid State Phenomena 155 (May 2009): 155–62. http://dx.doi.org/10.4028/www.scientific.net/ssp.155.155.
Full textAbstract:
Magnetite and Co ferrite particles were synthesized with control of particle size distribution via non-aqueous route. The XRD pattern shows the formation of single phase spinel structure with the particle size of 96 Å and 80 Å respectively for magnetite and cobalt ferrite. TEM image of the same shows the particles are nearly spherical with the size matches with that obtained from X-ray and the size distribution is less than 5%. Magnetic measurement also shows the particles of uniform size with high value of saturation magnetization at room temperature compared to that obtained by other route. SANS study confirms our results of monodispersed particles with spherical shape.
47
Vetrano, J. S., and C. H. Henager. "Measurement Of Interfacial Segregation In Aluminum-Magnesium Alloys Using A Feg-Tem And Eds." Microscopy and Microanalysis 5, S2 (August 1999): 160–61. http://dx.doi.org/10.1017/s1431927600014124.
Full textAbstract:
Aluminum-magnesium alloys are currently being utilized in lightweight automotive components and their good strength and weldability characteristics has made them candidates for increased use. The primary problem with using aluminum alloys for automotive applications is their relatively low formability. Superplastic forming (SPF) is a viable method for producing high elongations and is enabled in these alloys by the manipulation of intermetallic particles (e.g. Al3Sc) that restrict grain growth at the high homologous temperatures necessary for this technique [1]. SPF of Al-Mg-Mn-Sc alloy has yielded elongations of over 600% [2]. However, Al3Sc particles age rapidly at high temperatures which can reduce their strengthening characteristics following deformation. It has been experimentally observed that the addition of Zr to Al-Sc alloys retards the aging of the Al3Sc precipitates [3]. This is beneficial for high temperature conditions like superplastic forming and welding. In this study we examine the location of Zr in the strupturc and how it may be inhibiting particle aging.
48
Jia, Yufeng, Zhongqin Li, Chunhai Xu, Shuang Jin, and Haijun Deng. "A Comparison of Precipitation Measurements with a PWS100 Laser Sensor and a Geonor T-200B Precipitation Gauge at a Nival Glacial Zone in Eastern Tianshan, Central Asia." Atmosphere 11, no. 10 (October 10, 2020): 1079. http://dx.doi.org/10.3390/atmos11101079.
Full textAbstract:
Precipitation is a key process in the hydrologic cycle. However, accurate precipitation data are scarce in high mountainous areas, mainly restricted by complex topography, solid precipitation and sparse recording stations. In order to evaluate the quality of precipitation measurement, this study conducted a comparison campaign of precipitation measurements with the PWS100 laser sensor and the Geonor T-200B rain gauge for an entire year from 30 April 2018 to 1 May 2019 at an elevation of 3835 m in a nival glacial zone in eastern Tianshan, Central Asia. The results show that the daily precipitation values recorded by Geonor T-200B and PWS100 are well correlated and the annual precipitation amounts recorded by the two instruments differ by 7%, indicating good capabilities of both instruments in solid precipitation measurement. However, the amount of precipitation measured by Geonor T-200B was 36 mm lower in June to August and 120 mm higher in the remaining months compared with the values measured by PWS100. Our study indicated that Geonor T-200B is more efficient than PWS100 in terms of catching solid precipitation measurements. According to the PWS100 data, the experiment site was dominated by solid precipitation particles, accounting for 60% of total precipitation particles. Based on the precipitation particle and in-situ air temperature measurements, a set of temperature thresholds were established to discriminate rain, sleet and snow. The threshold temperature of rainfall and snowfall is −1.5 and 8 °C, respectively. When air temperature ranges from −1.5 to 8 °C, sleet occurs, meanwhile the ratio of rain to snow depends on air temperature.
49
Rose, D., S. S. Gunthe, E. Mikhailov, G. P. Frank, U. Dusek, M. O. Andreae, and U. Pöschl. "Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment." Atmospheric Chemistry and Physics 8, no. 5 (February 29, 2008): 1153–79. http://dx.doi.org/10.5194/acp-8-1153-2008.
Full textAbstract:
Abstract. Experimental and theoretical uncertainties in the measurement of cloud condensation nuclei (CCN) with a continuous-flow thermal-gradient CCN counter from Droplet Measurement Technologies (DMT-CCNC) have been assessed by model calculations and calibration experiments with ammonium sulfate and sodium chloride aerosol particles in the diameter range of 20–220 nm. Experiments have been performed in the laboratory and during field measurement campaigns, covering a wide range of instrument operating conditions (650–1020 hPa pressure, 293–303 K inlet temperature, 4–34 K m−1 temperature gradient, 0.5–1.0 L min−1 flow rate). For each set of conditions, the effective water vapor supersaturation (Seff, 0.05–1.4%) was determined from the measured CCN activation spectra (dry particle activation diameters) and Köhler model calculations. High measurement precision was achieved under stable laboratory conditions, where the relative standard deviations of Seff were as low as ±1%. During field measurements, however, the relative deviations increased to about ±5%, which can be mostly attributed to variations of the CCNC column top temperature with ambient temperature. The observed dependence of Seff on temperature, pressure, and flow rate was compared to the CCNC flow model of Lance et al. (2006). At high Seff the relative deviations between flow model and experimental results were mostly less than 10%, but at Seff≤0.1% they exceeded 40%. Thus, careful experimental calibration is required for high-accuracy CCN measurements – especially at low Seff. A comprehensive comparison and uncertainty analysis of the various Köhler models and thermodynamic parameterizations commonly used in CCN studies showed that the relative deviations between different approaches are as high as 25% for (NH4)2SO4 and 12% for NaCl. The deviations were mostly caused by the different parameterizations for the activity of water in aqueous solutions of the two salts. To ensure comparability of results, we suggest that CCN studies should always report exactly which Köhler model equations and parameters were used. Provided that the Aerosol Inorganics Model (AIM) can be regarded as an accurate source of water activity data for highly dilute solutions of (NH4)2SO4 and NaCl, only Köhler models that are based on the AIM or yield similar results should be used in CCN studies involving these salts and aiming at high accuracy. Experiments with (NH4)2SO4 and NaCl aerosols showed that the conditions of particle generation and the shape and microstructure of NaCl particles are critical for their application in CCN activation experiments (relative deviations up to 18%).
50
Vidaurre, German, John Hallett, and David C. Rogers. "Airborne Measurement of Liquid and Total Water Content." Journal of Atmospheric and Oceanic Technology 28, no. 9 (September 1, 2011): 1088–103. http://dx.doi.org/10.1175/jtech-d-10-05035.1.
Full textAbstract:
Abstract Two identical liquid water content (LWC) King probes—one total water content/liquid water content (TWC/LWC) Nevzorov probe and two constant-temperature T probes that are different in size to distinguish particles of different densities and diameters (section 2c)—were flown during the Alliance Icing Research Study (AIRS) II field campaign in the fall of 2003. This paper assesses measurements performed during several flights in mostly stratiform clouds. The two LWC King probes tracked well; however, discrepancies of up to 0.1 g m−3 for 1-s LWC measurements of 0.3 g m−3 were observed. Agreement between probes of different geometry and size was generally favorable, while levels of disagreement between the probes changed during numerous cloud penetrations from less than 20% up to a factor of 2, varying with flight conditions and microphysical structure of the cloud. Disagreement between probes was even larger when detecting ice water content (IWC). Measurement differences were attributed to different collection efficiencies resulting from preferred particle size, shape, and density and local aerodynamic effects around the aircraft. Measurements from a single probe are subject to uncertainty at a single point in time beyond the noise and drift level of the instrument. This uncertainty is evaluated considering particle habit, diameter, and density, and probe geometry and size, in addition to particle impact, breakup/splash, and bounce. From a working point of view, the intercomparison of several probes is subject to real but unknown spatial differences because of different locations between air samples. Comparison of identical probes is not appropriate because each measurement in itself is unique by definition. Thus, instead of duplication of instruments, subject to these levels of agreement, the use of a single probe is a practical approach while remaining aware of its limitations and capabilities.