Browsing by Subject "CONDENSATION"

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  • Seppa, Jeremias; Reischl, Bernhard; Sairanen, Hannu; Korpelainen, Virpi; Husu, Hannu; Heinonen, Martti; Raiteri, Paolo; Rohl, Andrew L.; Nordlund, Kai; Lassila, Antti (2017)
    Due to their operation principle atomic force microscopes (AFMs) are sensitive to all factors affecting the detected force between the probe and the sample. Relative humidity is an important and often neglected-both in experiments and simulations-factor in the interaction force between AFM probe and sample in air. This paper describes the humidity control system designed and built for the interferometrically traceable metrology AFM (IT-MAFM) at VTT MIKES. The humidity control is based on circulating the air of the AFM enclosure via dryer and humidifier paths with adjustable flow and mixing ratio of dry and humid air. The design humidity range of the system is 20-60 % rh. Force-distance adhesion studies at humidity levels between 25 % rh and 53 % rh are presented and compared to an atomistic molecular dynamics (MD) simulation. The uncertainty level of the thermal noise method implementation used for force constant calibration of the AFM cantilevers is 10 %, being the dominant component of the interaction force measurement uncertainty. Comparing the simulation and the experiment, the primary uncertainties are related to the nominally 7 nm radius and shape of measurement probe apex, possible wear and contamination, and the atomistic simulation technique details. The interaction forces are of the same order of magnitude in simulation and measurement (5 nN). An elongation of a few nanometres of the water meniscus between probe tip and sample, before its rupture, is seen in simulation upon retraction of the tip in higher humidity. This behaviour is also supported by the presented experimental measurement data but the data is insufficient to conclusively verify the quantitative meniscus elongation.
  • Odeh, Issam; Arar, Sharif; Al-Hunaiti, Afnan; Sa'aydeh, Hiyam; Hammad, Ghada; Duplissy, Jonathan; Vuollekoski, Henri; Korpela, Antti; Petäjä, Tuukka; Kulmala, Markku; Hussein, Tareq (2017)
    The quality and chemical composition of urban dew collections with dust precipitates without pre-cleaning of the collecting surface WSF (white standard foil) were investigated for 16 out of 20 collected samples with collected volumes ranging from 22 to 230 ml. The collection period was from March to July 2015 at an urban area, Jubaiha, which is located in the northern part of the capital city Amman, Jordan. The obtained results indicated the predominance of Ca2+ and SO42- ions (ratio 2.2: 1) that originated from Saharan soil dust; where the collected samples were alkaline (mean pH = 7.35) with high mineralization (429.22 mg/L) exceeding the previously reported dew values in Amman-Jordan. A relocation of NaCl and to a less extent Mg2+ from sea to land by Saharan wind is indicated by the percent sea-salt fraction calculations (over 100 and 52, respectively). The collected samples exhibited high total organic carbon (TOC) values ranging from 11.86 to 74.60 mg/L, presence of particulate settled material with turbidity ranging from 20.10 to 520.00 NTU, and presence of undesired elements like boron (mean = 1.48 mg/L) that made it different in properties from other dew water collections at clean surfaces, and exceeding the standard limits for drinking water for these parameters set by Jordanian Drinking Water standards (JS286/2015)/WHO standard. The quality of this water is more close to that for raw or agricultural water but if it is meant to be used as potable source of water, at least sand and activated charcoal filters are needed to purify it.
  • Kulmala, Markku; Nieminen, Tuomo; Nikandrova, Anna; Lehtipalo, Katrianne; Manninen, Hanna E.; Kajos, Maija K.; Kolari, Pasi; Lauri, Antti; Petaja, Tuukka; Krejci, Radovan; Hansson, Hans-Christen; Swietlicki, Erik; Lindroth, Anders; Christensen, Torben R.; Arneth, Almut; Hari, Pertti; Back, Jaana; Vesala, Timo; Kerminen, Veli-Matti (2014)
  • Stolzenburg, Dominik; Simon, Mario; Ranjithkumar, Ananth; Kuerten, Andreas; Lehtipalo, Katrianne; Gordon, Hamish; Ehrhart, Sebastian; Finkenzeller, Henning; Pichelstorfer, Lukas; Nieminen, Tuomo; Brilke, Sophia; Xiao, Mao; Amorim, Antonio; Baalbaki, Rima; Baccarini, Andrea; Beck, Lisa; Brakling, Steffen; Murillo, Lucia Caudillo; Chen, Dexian; Chu, Biwu; Dada, Lubna; Dias, Antonio; Dommen, Josef; Duplissy, Jonathan; El Haddad, Imad; Fischer, Lukas; Carracedo, Loic Gonzalez; Heinritzi, Martin; Kim, Changhyuk; Koenig, Theodore K.; Kong, Weimeng; Lamkaddam, Houssni; Lee, Chuan Ping; Leiminger, Markus; Li, Zijun; Makhmutov, Vladimir; Manninen, Hanna E.; Marie, Guillaume; Marten, Ruby; Mueller, Tatjana; Nie, Wei; Partoll, Eva; Petaja, Tuukka; Pfeifer, Joschka; Philippov, Maxim; Rissanen, Matti P.; Rorup, Birte; Schobesberger, Siegfried; Schuchmann, Simone; Shen, Jiali; Sipila, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Tauber, Christian; Tham, Yee Jun; Tome, Antonio; Vazquez-Pufleau, Miguel; Wagner, Andrea C.; Wang, Mingyi; Wang, Yonghong; Weber, Stefan K.; Wimmer, Daniela; Wlasits, Peter J.; Wu, Yusheng; Ye, Qing; Zauner-Wieczorek, Marcel; Baltensperger, Urs; Carslaw, Kenneth S.; Curtius, Joachim; Donahue, Neil M.; Flagan, Richard C.; Hansel, Armin; Kulmala, Markku; Lelieveld, Jos; Volkamer, Rainer; Kirkby, Jasper; Winkler, Paul M.; He, Xucheng (2020)
    In the present-day atmosphere, sulfuric acid is the most important vapour for aerosol particle formation and initial growth. However, the growth rates of nanoparticles (<10 nm) from sulfuric acid remain poorly measured. Therefore, the effect of stabilizing bases, the contribution of ions and the impact of attractive forces on molecular collisions are under debate. Here, we present precise growth rate measurements of uncharged sulfuric acid particles from 1.8 to 10 nm, performed under atmospheric conditions in the CERN (European Organization for Nuclear Research) CLOUD chamber. Our results show that the evaporation of sulfuric acid particles above 2 nm is negligible, and growth proceeds kinetically even at low ammonia concentrations. The experimental growth rates exceed the hard-sphere kinetic limit for the condensation of sulfuric acid. We demonstrate that this results from van derWaals forces between the vapour molecules and particles and disentangle it from charge-dipole interactions. The magnitude of the enhancement depends on the assumed particle hydration and collision kinetics but is increasingly important at smaller sizes, resulting in a steep rise in the observed growth rates with decreasing size. Including the experimental results in a global model, we find that the enhanced growth rate of sulfuric acid particles increases the predicted particle number concentrations in the upper free troposphere by more than 50 %.
  • Dingilian, Kayane K.; Halonen, Roope; Tikkanen, Valtteri; Reischl, Bernhard; Vehkamaki, Hanna; Wyslouzil, Barbara E. (2020)
    We studied the homogeneous nucleation of carbon dioxide in the carrier gas argon for concentrations of CO(2)ranging from 2 to 39 mole percent using three experimental methods. Position-resolved pressure trace measurements (PTM) determined that the onset of nucleation occurred at temperatures between 75 and 92 K with corresponding CO(2)partial pressures of 39 to 793 Pa. Small angle X-ray scattering (SAXS) measurements provided particle size distributions and aerosol number densities. Number densities of approximately 10(12)cm(-3), and characteristic times ranging from 6 to 13 mu s, resulted in measured nucleation rates on the order of 5 x 10(17)cm(-3)s(-1), values that are consistent with other nucleation rate measurements in supersonic nozzles. Finally, we used Fourier transform infrared (FTIR) spectroscopy to identify that the condensed CO(2)particles were crystalline cubic solids with either sharp or rounded corners. Molecular dynamics simulations, however, suggest that CO(2)forms liquid-like critical clusters before transitioning to the solid phase. Furthermore, the critical clusters are not in thermal equilibrium with the carrier gas. Comparisons with nucleation theories were therefore made assuming liquid-like critical clusters and incorporating non-isothermal correction factors.
  • Jokinen, T.; Sipilä, M.; Kontkanen, J.; Vakkari, V.; Tisler, P.; Duplissy, E.-M.; Junninen, H.; Kangasluoma, J.; Manninen, H. E.; Petäjä, T.; Kulmala, M.; Worsnop, D. R.; Kirkby, J.; Virkkula, A.; Kerminen, V.-M. (2018)
    Formation of new aerosol particles from trace gases is a major source of cloud condensation nuclei (CCN) in the global atmosphere, with potentially large effects on cloud optical properties and Earth's radiative balance. Controlled laboratory experiments have resolved, in detail, the different nucleation pathways likely responsible for atmospheric new particle formation, yet very little is known from field studies about the molecular steps and compounds involved in different regions of the atmosphere. The scarcity of primary particle sources makes secondary aerosol formation particularly important in the Antarctic atmosphere. Here, we report on the observation of ion-induced nucleation of sulfuric acid and ammonia-a process experimentally investigated by the CERN CLOUD experiment-as a major source of secondary aerosol particles over coastal Antarctica. We further show that measured high sulfuric acid concentrations, exceeding 10(7) molecules cm(-3), are sufficient to explain the observed new particle growth rates. Our findings show that ion-induced nucleation is the dominant particle formation mechanism, implying that galactic cosmic radiation plays a key role in new particle formation in the pristine Antarctic atmosphere.
  • Lahtinen, Maarit; Mikkilä, Joona Aleksi; Mikkonen, Kirsi S.; Kilpeläinen, Ilkka (2021)
    The complex chemical structure and the fact that many areas in pulping and lignin chemistry still remain unresolved are challenges associated with exploiting lignin. In this study, we address questions regarding the formation and chemical nature of the insoluble residual lignin, the presence of fatty acids in kraft lignin, and the origin of secoisolariciresinol structures. A mild thermal treatment of lignin at maximum kraft-cooking temperatures (similar to 170 degrees C) with tall oil fatty acids (TOFA) or in an inert solvent (decane) produced highly insoluble products. However, acetylation of these samples enabled detailed chemical characterization by nuclear magnetic resonance (NMR) spectroscopy. The results show that the secoisolariciresinol (beta-beta) structure in kraft lignin is formed by rearrangement of the beta-aryl ether structure. Furthermore, fatty acids bind covalently to kraft lignin by reacting with the stilbene structures present. It is highly probable that these reactions also occur during kraft pulping, and this phenomenon has an impact on controlling the present kraft pulping process along with the development of new products from kraft lignin.
  • Lynch, Benjamin J.; Palmerio, Erika; DeVore, C. Richard; Kazachenko, Maria D.; Dahlin, Joel T.; Pomoell, Jens; Kilpua, Emilia K. J. (2021)
    We present observations and modeling of the magnetic field configuration, morphology, and dynamics of a large-scale, high-latitude filament eruption observed by the Solar Dynamics Observatory. We analyze the 2015 July 9-10 filament eruption and the evolution of the resulting coronal mass ejection (CME) through the solar corona. The slow streamer-blowout CME leaves behind an elongated post-eruption arcade above the extended polarity inversion line that is only poorly visible in extreme ultraviolet (EUV) disk observations and does not resemble a typical bright flare-loop system. Magnetohydrodynamic (MHD) simulation results from our data-inspired modeling of this eruption compare favorably with the EUV and white-light coronagraph observations. We estimate the reconnection flux from the simulation's flare-arcade growth and examine the magnetic-field orientation and evolution of the erupting prominence, highlighting the transition from an erupting sheared-arcade filament channel into a streamer-blowout flux-rope CME. Our results represent the first numerical modeling of a global-scale filament eruption where multiple ambiguous and complex observational signatures in EUV and white light can be fully understood and explained with the MHD simulation. In this context, our findings also suggest that the so-called stealth CME classification, as a driver of unexpected or "problem" geomagnetic storms, belongs more to a continuum of observable/nonobservable signatures than to separate or distinct eruption processes.
  • Atashi, Nahid; Rahimi, Dariush; Al Kuisi, Mustafa; Jiries, Anwar; Vuollekoski, Henri; Kulmala, Markku; Vesala, Timo; Hussein, Tareq (2020)
    In this study, we performed model simulations to investigate the spatial, seasonal, and annual dew yield during 40 years (1979-2018) at ten locations reflecting the variation of climate and environmental conditions in Jordan. In accordance with the climate zones in Jordan, the dew formation had distinguished characteristics features with respect to the yield, seasonal variation, and spatial variation. The highest water dew yield (an overall annual mean cumulative dew yield as high as 88 mm) was obtained for theMountains Heights Plateau, which has a Mediterranean climate. The least dew yield (as low as 19 mm) was obtained inBadia, which has an arid climate. The dew yield had a decreasing trend in the past 40 years due to climate change impacts such as increased desertification and the potential of sand and dust storms in the region. In addition, increased anthropogenic air pollution slows down the conversion of vapor to liquid phase change, which also impacts the potential of dew formation. The dew yield showed three distinguished seasonal patterns reflecting the three climates in Jordan. TheMountains Heights Plateau(Mediterranean climate) has the highest potential for dew harvesting (especially during the summer) thanBadia(semi-arid climate).
  • Lehtipalo, Katrianne; Yan, Chao; Dada, Lubna; Bianchi, Federico; Xiao, Mao; Wagner, Robert; Stolzenburg, Dominik; Ahonen, Lauri R.; Amorim, Antonio; Baccarini, Andrea; Bauer, Paulus S.; Baumgartner, Bernhard; Bergen, Anton; Bernhammer, Anne-Kathrin; Breitenlechner, Martin; Brilke, Sophia; Buchholz, Angela; Mazon, Stephany Buenrostro; Chen, Dexian; Chen, Xuemeng; Dias, Antonio; Dommen, Josef; Draper, Danielle C.; Duplissy, Jonathan; Ehn, Mikael; Finkenzeller, Henning; Fischer, Lukas; Frege, Carla; Fuchs, Claudia; Garmash, Olga; Gordon, Hamish; Hakala, Jani; He, Xucheng; Heikkinen, Liine; Heinritzi, Martin; Helm, Johanna C.; Hofbauer, Victoria; Hoyle, Christopher R.; Jokinen, Tuija; Kangasluoma, Juha; Kerminen, Veli-Matti; Kim, Changhyuk; Kirkby, Jasper; Kontkanen, Jenni; Kuerten, Andreas; Lawler, Michael J.; Mai, Huajun; Mathot, Serge; Mauldin, Roy L.; Molteni, Ugo; Nichman, Leonid; Nie, Wei; Nieminen, Tuomo; Ojdanic, Andrea; Onnela, Antti; Passananti, Monica; Petäjä, Tuukka; Piel, Felix; Pospisilova, Veronika; Quelever, Lauriane L. J.; Rissanen, Matti P.; Rose, Clémence; Sarnela, Nina; Schallhart, Simon; Schuchmann, Simone; Sengupta, Kamalika; Simon, Mario; Sipilä, Mikko; Tauber, Christian; Tome, Antonio; Trostl, Jasmin; Väisänen, Olli; Vogel, Alexander L.; Volkamer, Rainer; Wagner, Andrea C.; Wang, Mingyi; Weitz, Lena; Wimmer, Daniela; Ye, Penglin; Ylisirniö, Arttu; Zha, Qiaozhi; Carslaw, Kenneth S.; Curtius, Joachim; Donahue, Neil M.; Flagan, Richard C.; Hansel, Armin; Riipinen, Ilona; Virtanen, Annele; Winkler, Paul M.; Baltensperger, Urs; Kulmala, Markku; Worsnop, Douglas R. (2018)
    A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NOx suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.
  • Stolzenburg, Dominik; Fischer, Lukas; Vogel, Alexander L.; Heinritzi, Martin; Schervish, Meredith; Simon, Mario; Wagner, Andrea C.; Dada, Lubna; Ahonen, Lauri R.; Amorim, Antonio; Baccarini, Andrea; Bauer, Paulus S.; Baumgartner, Bernhard; Bergen, Anton; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Mazon, Stephany Buenrostro; Chen, Dexian; Dias, Antnio; Draper, Danielle C.; Duplissy, Jonathan; El Haddad, Imad; Finkenzeller, Henning; Frege, Carla; Fuchs, Claudia; Garmash, Olga; Gordon, Hamish; He, Xucheng; Helm, Johanna; Hofbauer, Victoria; Hoyle, Christopher R.; Kim, Changhyuk; Kirkby, Jasper; Kontkanen, Jenni; Kuerten, Andreas; Lampilahti, Janne; Lawler, Michael; Lehtipalo, Katrianne; Leiminger, Markus; Mai, Huajun; Mathot, Serge; Mentler, Bernhard; Molteni, Ugo; Nie, Wei; Nieminen, Tuomo; Nowak, John B.; Ojdanic, Andrea; Onnela, Antti; Passananti, Monica; Petäjä, Tuukka; Quélever, Lauriane L. J.; Rissanen, Matti P.; Sarnela, Nina; Schallhart, Simon; Tauber, Christian; Tome, Antonio; Wagner, Robert; Wang, Mingyi; Weitz, Lena; Wimmer, Daniela; Xiao, Mao; Yan, Chao; Ye, Penglin; Zha, Qiaozhi; Baltensperger, Urs; Curtius, Joachim; Dommen, Josef; Flagan, Richard C.; Kulmala, Markku; Smith, James N.; Worsnop, Douglas R.; Hansel, Armin; Donahue, Neil M.; Winkler, Paul M. (2018)
    Nucleation and growth of aerosol particles from atmospheric vapors constitutes a major source of global cloud condensation nuclei (CCN). The fraction of newly formed particles that reaches CCN sizes is highly sensitive to particle growth rates, especially for particle sizes <10 nm, where coagulation losses to larger aerosol particles are greatest. Recent results show that some oxidation products from biogenic volatile organic compounds are major contributors to particle formation and initial growth. However, whether oxidized organics contribute to particle growth over the broad span of tropospheric temperatures remains an open question, and quantitative mass balance for organic growth has yet to be demonstrated at any temperature. Here, in experiments performed under atmospheric conditions in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN), we show that rapid growth of organic particles occurs over the range from -25 degrees C to 25 degrees C. The lower extent of autoxidation at reduced temperatures is compensated by the decreased volatility of all oxidized molecules. This is confirmed by particle-phase composition measurements, showing enhanced uptake of relatively less oxygenated products at cold temperatures. We can reproduce the measured growth rates using an aerosol growth model based entirely on the experimentally measured gas-phase spectra of oxidized organic molecules obtained from two complementary mass spectrometers. We show that the growth rates are sensitive to particle curvature, explaining widespread atmospheric observations that particle growth rates increase in the single-digit-nanometer size range. Our results demonstrate that organic vapors can contribute to particle growth over a wide range of tropospheric temperatures from molecular cluster sizes onward.
  • Yan, Chao; Yin, Rujing; Lu, Yiqun; Dada, Lubna; Yang, Dongsen; Fu, Yueyun; Kontkanen, Jenni; Deng, Chenjuan; Garmash, Olga; Ruan, Jiaxin; Baalbaki, Rima; Schervish, Meredith; Cai, Runlong; Bloss, Matthew; Chan, Tommy; Chen, Tianzeng; Chen, Qi; Chen, Xuemeng; Chen, Yan; Chu, Biwu; Dällenbach, Kaspar; Foreback, Benjamin; He, Xucheng; Heikkinen, Liine; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kokkonen, Tom; Kurppa, Mona; Lehtipalo, Katrianne; Li, Haiyan; Li, Hui; Li, Xiaoxiao; Liu, Yiliang; Ma, Qingxin; Paasonen, Pauli; Rantala, Pekka; Pileci, Rosaria E.; Rusanen, Anton; Sarnela, Nina; Simonen, Pauli; Wang, Shixian; Wang, Weigang; Wang, Yonghong; Xue, Mo; Yang, Gan; Yao, Lei; Zhou, Ying; Kujansuu, Joni; Petäjä, Tuukka; Nie, Wei; Ma, Yan; Ge, Maofa; He, Hong; Donahue, Neil M.; Worsnop, Douglas R.; Kerminen, Veli-Matti; Wang, Lin; Liu, Yongchun; Zheng, Jun; Kulmala, Markku; Jiang, Jingkun; Bianchi, Federico (2021)
    Intense and frequent new particle formation (NPF) events have been observed in polluted urban environments, yet the dominant mechanisms are still under debate. To understand the key species and governing processes of NPF in polluted urban environments, we conducted comprehensive measurements in downtown Beijing during January-March, 2018. We performed detailed analyses on sulfuric acid cluster composition and budget, as well as the chemical and physical properties of oxidized organic molecules (OOMs). Our results demonstrate that the fast clustering of sulfuric acid (H2SO4) and base molecules triggered the NPF events, and OOMs further helped grow the newly formed particles toward climate- and health-relevant sizes. This synergistic role of H2SO4, base species, and OOMs in NPF is likely representative of polluted urban environments where abundant H2SO4 and base species usually co-exist, and OOMs are with moderately low volatility when produced under high NOx concentrations.