Comprehensive modeling study of ozonolysis of oleic acid aerosol based on real-time, online measurements of aerosol composition

Real-time control of manufacturing processes is a challenging issue for nowadays industry. The need for ever more efficient production requires new strategies in order to make correct decisions in an acceptable time. In a large number of cases, operators working on a CNC machine tool have a reduced number of possibilities for interacting in real-time with the machine. Numerical simulation based control is in that sense an appealing alternative to the conventional approach since it provides the operator with an additional source of information, confirming his choices or in reverse suggesting a more adapted strategy. The main goal of this work is to propose a method to move from a bilateral approach (operator and CNC controller) to a trilateral one where the simulation is an active component of the manufacturing process. This paper focuses on a simple issue sometimes encountered in milling processes: how to remove a constant thickness of material at the surface of a part whose exact geometry is unknown? The difficulty lies in the choice of an appropriate trajectory for the tool. So far the method which is employed consists in acquiring the geometry of the part thanks to a palpation step made prior to milling. However, this step has to be repeated for each part and can become rather fastidious as the size of the part increases. The approach presented here gets rid of the palpation step and makes use of online measurements for identifying the real geometry and correcting the trajectory of the tool in accordance. By monitoring the forces applying on the tool (directly on the NC), we have access to the milling depth and therefore to the geometry of the part at several locations along the trajectory of the tool. This information is used as an input data for our numerical model running on an external device, which finally derives an approximation for the geometry. An optimized trajectory is then obtained and is updated on the machine. This procedure is repeated as the tool moves forward and it allows for a fast and robust on-line correction of the toolpath.

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Polarization properties of aerosol particles over western Japan: classification, seasonal variation, and implications for air quality

10.5194/acp-2015-904 ◽

2016 ◽

Cited By ~ 1

Author(s):

X. L. Pan ◽

I. Uno ◽

Y. Hara ◽

K. Osada ◽

S. Yamamoto ◽

...

Keyword(s):

Air Quality ◽

Aerosol Particles ◽

Threshold Value ◽

Sea Salt ◽

Spherical Particles ◽

Aerosol Composition ◽

Anthropogenic Pollutants ◽

Online Measurements ◽

Dependent Polarization ◽

Western Japan

Abstract. Ground-based observations of the polarization properties of aerosol particles using a polarization optical particle counter (POPC) were performed from October 2013 to January 2015 at a suburban site in the Kyushu area of Japan. By conducting an analysis of online measurements of aerosol composition, we investigated size-dependent polarization characteristics for three typical aerosol types (anthrop ogenic pollutants, dust, and sea salt). We found that, for supermicron particles, its depolarization ratio (DR, the fraction of s-polarized signal in the total back ward light scattering signal) generally increased with the particle size, and a threshold value of 0.1 could be used to identify the irsphericity. In summer, air pollution was less serious, and the DR of aerosol particles was relatively small due to the influence of spherical sea salt particles in high humidity conditions. This study indicated that air masses were transported across the Asian continent and contained not only anthropogenic pollutants, but also large amounts of non-spherical particles (i.e., dust), which could impact on the air quality in western Japan, especially in winter and spring. The variation of number fraction of spherical particles did not correlate with relative humidity averaged along the trajectories of air parcels, indicating the coexistence of hydrophobic substances (e.g., mineral dust and organics), although the sulfate and nitrate mass concentrations were high.

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Measured and modelled Cloud Condensation Nuclei (CCN) concentration in São Paulo, Brazil: the importance of aerosol size-resolved chemical composition on CCN concentration prediction

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-32353-2013 ◽

2013 ◽

Vol 13 (12) ◽

pp. 32353-32389 ◽

Cited By ~ 1

Author(s):

G. P. Almeida ◽

J. Brito ◽

C. A. Morales ◽

M. F. Andrade ◽

P. Artaxo

Keyword(s):

Chemical Composition ◽

Real Time ◽

Cloud Condensation Nuclei ◽

Bulk Composition ◽

Sao Paulo ◽

Aerosol Size Distribution ◽

São Paulo ◽

Condensation Nuclei ◽

Aerosol Composition ◽

The Impact

Abstract. Measurements of cloud condensation nuclei (CCN), aerosol size distribution and non-refractory chemical composition were performed from 16 to 31 October 2012 in the São Paulo Metropolitan Area (SPMA), Brazil. CCN measurements were performed at 0.2%, 0.4%, 0.6%, 0.8% and 1.0% water supersaturation and were subsequently compared with Köhler theory, considering the chemical composition. Real-time chemical composition has been obtained deploying for the first time in SPMA an Aerosol Chemical Ionization Monitor (ACSM). CCN closure analyses were performed considering internal mixture. Average aerosol composition during the studied period yielded 4.81 ± 3.05, 3.26 ± 2.10, 0.30 ± 0.27, 0.52 ± 0.32, 0.37 ± 0.21 and 0.04 ± 0.04 μg m−3 for organics, BC, NH4, SO4, NO3 and Cl, respectively. Particle number concentration was 12 813 ± 5350 cm−3, being a large fraction in the nucleation mode. CCN concentrations were on average 1090 ± 328 cm−3 and 3570 ± 1695 cm−3 at SS = 0.2% and SS = 1.0%, respectively. Results show an increase in aerosol hygroscopicity in the afternoon as a result of aerosol photochemical processing, leading to an enhancement of both organic and inorganic secondary aerosols in the atmosphere, as well as an increase in aerosol average diameter. Considering the bulk composition alone, CCN concentrations were substantially overpredicted (29.6 ± 45.1% at 0.2% supersaturation and 57.3 ± 30.0% at 1.0% supersaturation). Overall, the impact of composition on the calculated NCCN decreases with decreasing supersaturation, partially because using bulk composition introduces less bias for large diameters and lower critical supersaturations. Results suggest that the consideration of only inorganic fraction improves the calculated NCCN. Introducing a size-dependent chemical composition based on filter measurements from previous campaigns has considerably improved simulated values for NCCN (average overprediction error 3.0 ± 33.4% at 0.20% supersaturation and average under prediction error 2.4 ± 20.5% at 1.0% supersaturation). This study provides the first insight on aerosol real-time composition and hygroscopicity on a~site strongly impacted by emissions of a unique vehicular fleet due to the extensive biofuel usage.

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Corrigendum to “Comprehensive modeling study analyzing the insights of the NO–NO2 conversion process in current diesel engines” [Energy Convers. Manag. 84 (2014) 691–700]

Energy Conversion and Management ◽

10.1016/j.enconman.2014.06.012 ◽

2014 ◽

Vol 85 ◽

pp. 561

Author(s):

J. Benajes ◽

J.J. López ◽

R. Novella ◽

P. Redón

Keyword(s):

Diesel Engines ◽

Conversion Process ◽

Comprehensive Modeling ◽

Modeling Study

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Real-Time Simulation Modeling Study of the HVDC Circuit Breaker Based on Nodal Dynamic Equation

2019 IEEE 3rd Conference on Energy Internet and Energy System Integration (EI2) ◽

10.1109/ei247390.2019.9061956 ◽

2019 ◽

Author(s):

Bin Chang ◽

Chang Lin ◽

Yixuan Peng ◽

Jiapei Zhou ◽

Hui Pang ◽

...

Keyword(s):

Real Time ◽

Dynamic Equation ◽

Simulation Modeling ◽

Circuit Breaker ◽

Real Time Simulation ◽

Time Simulation ◽

Modeling Study

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Sources and atmospheric dynamics of organic aerosol in New Delhi, India: insights from receptor modeling

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-735-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 735-752 ◽

Cited By ~ 7

Author(s):

Sahil Bhandari ◽

Shahzad Gani ◽

Kanan Patel ◽

Dongyu S. Wang ◽

Prashant Soni ◽

...

Keyword(s):

Source Apportionment ◽

Chemical Characterization ◽

Organic Aerosol ◽

Receptor Modeling ◽

World Health ◽

Aerosol Composition ◽

Time Resolved ◽

Online Measurements ◽

Using Data ◽

Health Organization

Abstract. Delhi, India, is the second most populated city in the world and routinely experiences some of the highest particulate matter concentrations of any megacity on the planet, posing acute challenges to public health (World Health Organization, 2018). However, the current understanding of the sources and dynamics of PM pollution in Delhi is limited. Measurements at the Delhi Aerosol Supersite (DAS) provide long-term chemical characterization of ambient submicron aerosol in Delhi, with near-continuous online measurements of aerosol composition. Here we report on source apportionment based on positive matrix factorization (PMF), conducted on 15 months of highly time-resolved speciated submicron non-refractory PM1 (NR-PM1) between January 2017 and March 2018. We report on seasonal variability across four seasons of 2017 and interannual variability using data from the two winters and springs of 2017 and 2018. We show that a modified tracer-based organic component analysis provides an opportunity for a real-time source apportionment approach for organics in Delhi. Phase equilibrium modeling of aerosols using the extended aerosol inorganics model (E-AIM) predicts equilibrium gas-phase concentrations and allows evaluation of the importance of the ventilation coefficient (VC) and temperature in controlling primary and secondary organic aerosol. We also find that primary aerosol dominates severe air pollution episodes, and secondary aerosol dominates seasonal averages.

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Composition and properties of atmospheric particles in the eastern Atlantic and impacts on gas phase uptake rates

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-9299-2009 ◽

2009 ◽

Vol 9 (23) ◽

pp. 9299-9314 ◽

Cited By ~ 43

Author(s):

J. D. Allan ◽

D. O. Topping ◽

N. Good ◽

M. Irwin ◽

M. Flynn ◽

...

Keyword(s):

Optical Absorption ◽

Size Distribution ◽

Cape Verde ◽

Sea Salt ◽

Differential Mobility ◽

Aerosol Composition ◽

Ambient Humidity ◽

Uptake Rates ◽

Online Measurements ◽

Good Agreement

Abstract. Marine aerosol composition continues to represent a large source of uncertainty in the study of climate and atmospheric chemistry. In addition to their physical size and chemical composition, hygroscopicity plays a significant role, increasing the particles' surface areas and scattering potential. Simultaneous aerosol measurements were performed on board the RRS Discovery and at the Cape Verde atmospheric observatory during the Aerosol Composition and Modelling in the Marine Environment (ACMME) and Reactive Halogens in the Marine Boundary Layer (RHAMBLE) experiments. These included online measurements of number and dry size and bulk collection for offline analysis of aqueous ions. In addition, the measurements on board the Discovery included online measurements of composition using an Aerodyne Aerosol Mass Spectrometer, optical absorption using a Multi Angle Absorption Photometer, ambient humidity size distribution measurements using a humidified differential mobility particle sizer (DMPS) and optical particle counter (OPC) and hygroscopicity measurements with a hygroscopicity tandem differential mobility analyser (HTDMA). Good agreement between platforms in terms of the sea salt (ss) and non sea salt (nss) modes was found during the period when the Discovery was in close proximity to Cape Verde and showed a composition consistent with remote marine air. As the Discovery approached the African coast, the aerosol showed signs of continental influence such as an increase in particle number, optical absorption, enhancement of the nss mode and dust particles. The Cape Verde site was free of this influence during this period. Chloride and bromide showed concentrations with significant deviations from seawater relative to sodium, indicating that atmospheric halogen processing (and/or acid displacement for chloride) had taken place. The time dependent ambient size distribution was synthesised using humidified DMPS and OPC data, corrected to ambient humidity using HTDMA data. Heterogeneous uptake rates of hypoiodous acid (HOI) were also predicted and the nss accumulation mode was found to be the most significant part of the size distribution, which could act as an inert sink for this species. The predicted uptake rates were enhanced by around a factor of 2 during the African influence period due to the addition of both coarse and fine particles. The hygroscopicity of the nss fraction was modelled using the Aerosol Diameter Dependent Equilibrium Model (ADDEM) using the measured composition and results compared with the HTDMA data. This was the first time such a reconciliation study with this model has been performed with marine data and good agreement was reached within the resolution of the instruments. The effect of hygroscopic growth on HOI uptake was also modelled and ambient uptake rates were found to be approximately doubled compared to equivalent dry particles.

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